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With the rapid deployment of 5G wireless networks across the globe, precise positioning has become essential for many vertical industries reliant on 5G. The predominantly non-line-of-sight (NLOS) propagation instigated by the obstacles in the surrounding environment, especially in metro city areas, has made it particularly difficult to achieve high estimation accuracy for positioning algorithms that necessitate direct line-of-sight (LOS) transmission. In this scenario, correctly identifying the line-of-sight condition has become extremely crucial in precise positioning algorithms based on 5G. Even though numerous scientific studies have been conducted on LOS identification in the existing literature, most of these research works are based on either ultra-wideband or Wi-Fi networks. Therefore, this thesis focuses on this hitherto less investigated area of line-of-sight detection for 5G wireless channels. This thesis examines the feasibility of LOS detection using three widely used channel models, the Tapped Delay Line (TDL), the Clustered Delay Line (CDL), and the Winner II channel models. The 5G-based simulation environment was constructed with standard parameters based on 3GPP specifications using MATLAB computational platform for the research. LOS and NLOS channels were defined to transmit random signal samples for each channel model where the received signal was subjected to Additive White Gaussian Noise (AWGN), imitating the authentic propagation environment. Variable channel conditions were simulated by randomly alternating the signal-to-noise ratio (SNR) of the received signal. The research mainly focuses on machine learning (ML) based LOS classification. Additionally, the threshold-based hypothesis was also deployed for the same scenarios as a benchmark. The main objectives of the thesis were to find the statistical features or the combination of statistical features of the channel impulse response (CIR) of the received signal, which provide the best results and to identify the most effective machine learning method for LOS/NLOS classification. Furthermore, the results were verified through actual measurement samples obtained during the NewSense project. The results indicate that the time-correlation feature of the channel impulse response used in isolation would be effective in LOS identification for 5G wireless channels. Additional derived features of the CIR do not significantly increase the classification accuracy. Positioning Reference Signals (PRS) were found to be more appropriate than Sounding Reference Signals (SRS) for LOS/NLOS classification. The study reinforced the significance of selecting the most suitable machine learning algorithm and kernel function as relevant for the task of obtaining the best results. The medium Gaussian support vector machines ML algorithm provided the overall highest precision in LOS classification for simulated data with up to 98% accuracy for the Winner II channel model with PRS. The machine learning algorithms proved to be considerably more effective than conventional threshold-based detection for both simulated and real measurement data. Additionally, the Winner II model with the richest features presented the best results compared with CDL and TDL channel models.

Microgrids might enable environmental and economic improvements to the electric grid. The introduction of renewable energy sources to the power supply has opened new doors for a cleaner power system and novel grid structure changes such as microgrids. Microgrids are local power networks that can operate in grid-connected or islanded mode. One of the main challenges of microgrids is reliable and accurate protection. Intermittent generation and multiple modes of operation might change fault current behaviour drastically. Protection schemes must always function regardless of network topology, mode of operation, or generation level. Simulation case studies are helpful to test microgrid protection schemes for different microgrid states. In this thesis work, a microgrid is modelled to the needed extent for protection studies using PSCAD software. Protection use cases are simulated with PSCAD to demonstrate protection considerations for microgrids operating in grid-connected and islanded modes.

Trading between transmit waveform quality and power efficiency is one of the most challenging issues in radio transmitter implementation. To this end, digital predistortion is the de-facto solution for mitigating power amplifier (PA) nonlinear distortion in cellular base-stations due to its high flexibility and good linearization performance. Theoretically, it is convenient to describe predistorter (PD) transfer function as the mathematical inverse of the PA transfer function, and PD modeling is often performed through parametric methods. Thus, an additional feedback loop is required in the system for PD model parameter estimation. PA is an analog device and DPD is a part of digital front-end, implying that PA output signal is needed to be downconverted to baseband and sampled in the parameter estimation path. Consequently, it is required to employ additional components in the feedback loop such as attenuator, downconverter, and analog-to-digital converter (ADC). In order to be able to capture higher order nonlinearities, it is necessary to perform upsampling operation, which implies that in addition to digital-to-analog converters (DACs) in the forward loop, the components in the feedback loop should support higher bandwidths than the original transmission bandwidth. Additionally, to have a good linearization performance, a high resolution ADC is required. Having an ADC/DAC that supports wide bandwidth and has high resolution is directly increasing the material cost and power consumption. When future millimeter-wave (mmWave) systems are considered, adopting DPD becomes even more complex and costly due to wider waveform bandwidths and employing active antenna arrays. Alternative to DPD, receiver based approaches, referred to as digital post-distortion (DPoD), can be utilized to mitigate the nonlinear effects of transmitter PA. Naturally, receiver side techniques do not provide any improvement in terms of out-of-band (OOB) emission issues, rather they aim to improve received signal error vector magnitude (EVM). As the radiated power at mmWave is typically EVM limited and OOB emission requirements are relaxed compared to sub-6 GHz band, DPoD can offer means for improved network energy-efficiency. Several iterative DPoD methods are proposed in the literature such as power amplifier nonlinearity cancellation (PANC), and reconstruction of distorted signals (RODS). In this thesis, we present a non-iterative computationally efficient receiver side nonlinearity mitigation technique, referred to as digital post-inverse (DPoI), along with the parameter estimation approach targeting existing 5G NR standard-compliant reference signal. The receiver EVM performance of presented approach is analyzed by using computer simulations. It is seen that DPoI can reach similar or improved performance compared to the iterative PANC method, which is chosen as a reference DPoD method. Moreover, it is shown that both DPoD methods overperform ideally linearized transmitter PA under strong nonlinear conditions, which allows higher power efficiency when receiver side techniques are employed.

The popularity of renewable energy makes the use of battery energy storage systems (BESS) in the grid very attractive. BESS can support the intermittent power output of renewable energy sources. BESS can also provide a support during and after grid failure and even provide black-start capability in case of a blackout. Li-ion batteries are mainly used for these BESS because of their high energy density. In this thesis, the parameters affecting on the fault current of the battery in a BESS are modeled. In most studies around BESS, the inverter has gotten more attention than the battery part. However, the battery part behaves different than a simple DC voltage source. It is evaluated to what extent the behaviour of the battery affects the fault current fed by a BESS. The focus is on the open-circuit voltage (OCV) and internal resistance (Rint) of the battery. The state of charge (SoC), operating temperature, C-rate and state of health (SoH) of the battery affect this voltage and resistance. The behavior of the inverter is also taken into account to get a realistic BESS model. The developed model uses only data available in the manufacturer’s datasheets and information from existing studies. Today, a general fault model already exists for conventional generators, e.g., synchronous generators, but for inverter-based distributed energy resources (IBDER), e.g. BESS, there is not yet a generally accepted model for fault current calculations. There is a great need for simplified fault current models in the industry. These fault models are needed to get the overall dynamic fault response. One possible application is the sizing of overcurrent protection devices. If a BESS feeds in island mode, the available fault current will often be smaller due to the sensitive components that can handle less fault current than robust synchronous or asynchronous machines. These robust generators can provide high short-circuit currents for a short amount of time. The BESS model is incorporated into a simulation software program, here Matlab Simulink, to perform simulations

The increasing number of airports pursuing sustainability goals through electrification faces challenges when the existing electrical network cannot meet demands. In an effort to reduce the carbon footprint, airports need to take into account the environmental impact of the entire electrification process. It is, therefore, crucial to consider how electricity is generated. To minimize emissions and reduce the carbon footprint of airport operations, it's important to use renewable energy sources that are compatible with the airport's specific regulations. It might be challenging to meet the demand for electricity at all times when renewable energy sources (RES) like solar or wind power don't supply energy consistently or predictably. Batteries are frequently combined with RES to improve the system's overall efficiency in order to solve this problem. Properly forecasting future load patterns is crucial in determining the appropriate size and capacity of a renewable energy system that combines photovoltaic solar panels with battery energy storage systems. The present study investigates the feasibility of electrifying an airport using a microgrid solution that includes photovoltaic (PV) solar panels and battery energy storage systems (BESS). The study examines the energy flow of the airport under five different scenarios, which include the existing load, the addition of electric aircraft, the addition of E-bus load, the addition of electric ground handling equipment (GHE) loads, and the addition of electric vehicles. To accomplish this, we provide modeling and simulation to incorporate electrified loads that will be present in the future. Moreover, a pre-built simulator based on cost minimization is used to optimize the sizing of the PV and BESS components of the microgrid solution. Energy flow analysis, which gauges the amount of energy received and given to the network, is the foundation for the economic analysis of the microgrid solution. On the basis of this study, the annual cost of electricity purchase is then determined and compared.

With the ever-increasing demand for more powerful chips, it is necessary to integrate multiple circuits inside a chip. These chips are called a system on a chip (SoC). Even though SoCs integrate more and more functionality inside a single chip they still require a printed circuit board which at least provides power and input and output connectors. Tampere University together with multiple companies started SoC Hub project. The goal of this project is to develop a system on a chip and increase Finnish system on a chip design expertise. The target is to develop one system on a chip in a year with three SoCs in total. The goal of this master’s thesis is to design a printed circuit board that can be used to test the first iteration of the SoC. Printed circuit boards which are designed for testing have three main functions: provide power, provide input and output connectors and their circuitry, and to make testing as easy as possible. This system on a chip requires three different power rails, which must be turned on and off in a sequence and they must also be monitored in case of a fault. For this purpose, a power management system was developed in which a microcontroller monitors and controls the power rails. On the printed circuit board most of the input and output connectors use pin headers. The pin headers make testing easy as most signals are available in simple pin headers. Some signals also have more specialized connectors such as an SD card socket. Testability was also a major concern when deciding the stack up of the printed circuit board. All signals are routed on the outer layers so that they are easily available and can be slightly modified if needed. Some difficulties were also faced during the design process of the printed circuit board. Of these the biggest was the global chip shortage, because of which most of the chips that could have been used were not available. Due to chip shortage most of the chips had to be changed during the design phase and some chips had to be replaced by alternative means like using ready-made modules. Despite these problems the printed circuit boards were designed and manufactured before the SoCs arrived. The printed circuit boards were tested to be functional after which they could be used for their intended purpose of testing the SoCs.

Over the years, more distributed generation based on renewable energy sources are added to the distribution networks, therefore, active distribution network management is necessary to address local network congestion and voltage issues. Congestion control is one of the most hopeful approaches to resolving network issues among the diverse options. Traditionally, the transmission grid has been the level at which congestion management systems have been managed. However, the control method would have to be extended to the distribution network as well due to the widespread use of Distributed Generators (DGs) and the predicted harsh loading situations. Recently, scholars and others working in the electric grid industry have been more interested in strategies for reducing congestion in distribution networks and non-market-based approaches have been proposed. However, it might not be the best and most economical choice depending on the use case scenario. This paper presents an evaluation of four local flexibility market operators with the aim of reducing investment on the grid through network reinforcement. While network reinforcement is expensive, it is often the first option used by DSOs to address congestion issues since DSOs have done it repeatedly and are technically capable of doing so. In addition, reinforcement is a trustworthy solution. To address these problems based on the market, local flexibility markets are being developed. Flexibility markets are an effective strategy for maximizing the efficiency of the current distribution grids. Piclo Flex, Enera, GOPACS, and NODES are four innovative initiatives that incorporate flexibility markets that we evaluated in this thesis. There are differences amongst the projects in terms of the degree to which the flexibility markets are integrated into other existing markets, the quality of flexible service, the third-party market operators, the use of standardized commodities, and grid rules that require TSO-DSO/DSO-DSO coordination. Because each project has a unique vision, set of use cases, or level of project maturity, the answers to these questions vary. Our case study examination of the four ground-breaking projects will help the reader to understand the local flexibility markets and identify the most promising flexibility market operator to use when we are trying to postpone or defer network reinforcement which in turn reduces the investment on the grid.

DC/AC converters are power electronic devices which convert direct current (DC) electricity into alternating current (AC) electricity. They are known as inverters and are commonly used to connect renewable energy resources to the electricity grid, or to drive motors in electric transportation applications amongst many other uses. In the race to combat global climate change and reduce carbon emissions, the prevalence of renewable energy resources and electric transportation is set to increase, and with it, the need for energy efficient, low cost, and compact power electronic converters as an enabling technology. Inverter output needs to be conditioned using passive components as filters since it contains high levels of unwanted harmonic content which leads to undesirable effects in power systems and electrical machines. Strict industry standards dictate the level of filtering required. Passive components remain a stumbling block in improving the size, cost, and efficiency of inverter systems. It is for this reason that the development of fast and accurate design and modelling tools for passive components is needed in order to easily study and optimise their performance. In this thesis, a way of rapidly designing, modelling, and constructing filter inductors for DC/AC inverters is investigated. A design tool is developed to provide multiple design possibilities by varying geometric parameters. The designs are then analysed using a MATLAB Simulink inductor model which provides accurate information about the losses in the designed inductors. Of the hundreds of inductors designed, a few are selected to be constructed in an effort to validate the design tool and simulation model. The construction process highlighted challenges in prototyping inductors with non-standard geometries. Recommendations are given on how to improve the design tool, simulation model and construction process going forward.

Tämä työ on kirjallisuusselvitystyö erilaisista akkujen tila-analyysimenetelmistä. Työssä keskitytään käsittelemään erityisesti impedanssispektroskopian menetelmiä, etenkin kanttiaaltoja hyödyntävää pseudo-satunnoista binäärisekvenssiä (engl. pseudo.random binary sequencing, PSBS), sekä siniaaltoja hyödyntävää sähkökemiallista impedanssi spektroskopiaa (engl. electrochemical impedance spectroscopy, EIS). Työssä päätettiin tarkastella pääasiassa litium-ioni-akkuja (li-ion), sillä on ennustettu, että tulevaisuudessa pääosa akkujen kysynnän kasvusta tullaan kattamaan li-ioni-akuilla. Työssä luotiin simulaatio li-ioni-akun sähköisen mallin tutkimiseen Simulinkissä. Simulaation tarkoituksena on EIS- ja PRBS-menetelmien vertailu akkujen analysointimenetelminä. Työn simulaatio-osuudessa käsitellään myös, miten näiden kahden signaalityypin ominaisuuksien ja mittausjärjestelyn parametrien muutoksilla voidaan vaikuttaa mittaustuloksiin. Perinteinen EIS-menetelmä on todella hidas, joten se sopii paremmin sovellutuskohteisiin, joissa ei ole niinkään väliä, vaikka akkujärjestelmä joutuisikin olemaan vakaassa tilassa pitkiäkin aikoja. EIS-menetelmän parhaita puolia ovat sen tarkkuus, sekä vääristymiensietokyky. Perinteisessä EIS-menetelmässä käytettäviä siniaaltosignaaleja on kuitenkin hankalaa tuottaa. PRBS-menetelmä vaikuttaisi sopivan paremmin sähköautojen kaltaisiin järjestelmiin, joissa käyttöympäristö voi muuttua äkisti, ja joissa järjestelmää ei voi pitää pitkiä aikoja vakaassa tilassa. Tämä johtuu lyhyistä mittausajoista. PRBS-menetelmä sopii hyvin myös sulautettuihin järjestelmiin, mikä johtuu sen signaalien kanttiaaltomuodosta. Kanttiaaltoja on helpompaa tuottaa, ja ne vaativat vähemmän prosessointitehoa, kuin siniaallot. Epälineaariset vääristymät vaikuttavat kuitenkin PRBS-menetelmään herkemmin kuin perinteiseen EIS-menetelmään. This work is a literature review of different battery state analysis techniques. The focus is mainly on impedance spectroscopy methods, especially square wave signals using pseudorandom binary sequencing (PRBS) and traditional sinusoidal signals using electrochemical impedance spectroscopy (EIS). Lithium-ion batteries (LIBs) were chosen as the main battery type to be focused on because it has been predicted that most of the growth in demand for batteries in the future will be covered by LIBs. A simulation for examining an electrical model of a LIB was created in Simulink. The purpose of this simulation is to allow the comparison of EIS and PRBS methods as battery analysis methods. The simulation part also examines how changing different attributes of the two signal types and the measurement setup affect the measurement results. Traditional EIS is very slow, and thus it is better suited for applications where it does not matter if the battery system is needed to be at steady-state for long periods of time. The biggest advantage of the EIS method is perhaps its great accuracy as well as its resiliency to distortions. However, the sine wave signals used in traditional EIS are hard to produce. PRBS method appears to be better suited for systems such as electric vehicles, for which the operating conditions can change rapidly, and the system cannot be maintained in a steady-state for extended periods of time. This is due to short measurement times. The PRBS method is also easily implementable in embedded systems due to the square nature of the signals. Square waves are easier to produce, and they require less processing power than sinusoidal signals. However, PRBS method is more prone to nonlinear distortions than the traditional EIS method.

An on-body injector (OBI) is a medical device, which is designed to deliver larger volumes (>2mL) of drug subcutaneously via electromechanical or mechanical driving system and to be disposed of after its use making it a single-use device. Therefore, a high environmental impact can be expected. To address the issue of a possibly high environmental impact of single-use on-body injectors, this work aims to provide a comprehensive evaluation of the environmental impact of the full life cycle of OBIs and to develop work streams that are required to launch a take-back strategy to enable future recycling processes. The environmental impact is analysed using the Life Cycle Assessment (LCA) methodology and the Ecoinvent database. The first impact calculations are performed from the point of raw material extraction until the OBI reaches the distributor (cradleto-gate). The second impact calculations are performed with the full life cycle, including different end-of-life scenarios. Traditional landfill disposal is compared, to medical waste incineration and recycling through mail-back and take-back via pharmacy/hospital. In addition, hospital and supplier interviews are conducted to understand the practical measures surrounding take-back strategies. The cradle-to-gate LCA results indicate that the transportation part of the life cycle contributes to more than half of the environmental impact, followed by production and packaging. A single largest contributor is the production of the printed circuit board assembly (PCBA), and therefore its recycling should be prioritized in the end-of-life. The cradle-to-grave and cradle-to-cradle LCA results indicate that recycling through a mail-back scenario is environmentally better compared to take-back via a pharmacy or hospital. The differentiating factor is the lack of private car travel in a mail-back scenario. Both take-back scenarios were environmentally better than incineration. However, household disposal to a landfill was clearly less impactful due to the lack of energy and resource consumption in the process. Based on the hospital interview, a take-back program is feasible only with minimal exposure to hazardous material or with minimal effort by the personnel. Lastly, a sensitivity analysis of the LCA highlighted the importance of maximizing the take-back user engagement rate over maximizing the PCBA recycling rate. Vartaloon asennettu injektori (On-body injector, OBI) on lääketieteellinen laite, joka on suunniteltu annostelemaan suurempia määriä (>2mL) lääkettä ihonalaisesti sähkömekaanisen tai mekaanisen käyttöjärjestelmän kautta. OBI on kertakäyttöinen laite, jonka takia sen elinkaaresta voidaan odottaa aiheutuvan merkittäviä haitavaikutuksia ympäristölle. Vähentääkseen kertakäyttöisten vartaloon asetettavien lääkeruiskujen mahdollia negatiivisia ympäristövaikutuksia, tämän työn tavoitteena on muodostaa analyysi OBI:n koko elinkaaren ympäristövaikutuksista ja kehittää kattava suunnitelma takaisinottostrategialle kierrätyksen mahdollistamiseksi. Ympäristövaikutuksia analysoidaan käyttämällä Life Cycle Assessment (LCA) -metodologiaa ja Ecoinvent-tietokantaa. Ensimmäiset iteraatiot laskuista tehdään raakaaineen louhinnasta siihen asti, kunnes tuote saavuttaa jakelijan (cradle-to-gate). Seuraavat iteraatiot laskuista tehdään koko elinkaarelle, mukaan lukien myös erilaiset jäteskenaariot. Perinteistä kotitalousjätteeksi päätymistä verrataan lääkejätteen polttoon ja kierrätykseen postitse sekä apteekin tai sairaalan kautta tapahtuvaan takaisinottoon. Lisäksi työhön kuuluu haastatteluja sairaalan ja tuotetoimittajan edustajien kanssa. Cradle-to-gate laskujen tulokset osoittavat, että kuljetusosuus muodostaa yli puolet elinkaaren ympäristövaikutuksista. Seuraavaksi tulevat tuotannosta ja pakkauksesta aiheutuvat vaikutukset. Suurin yksittäinen tekijä on PCBA:n tuotanto ja siksi sen kierrätys tulisi asettaa etusijalle kierrätysprosessissa. Cradle-to-grave ja cradle-to-cradle laskujen tulokset osoittavat, että takasinotto postitse -skenaario on ympäristön kannalta parempi verrattuna apteekin tai sairaalan kautta tapahtuvaan palautukseen. Erottava tekijä on yksityisautolla tapahtuvan matkustuksen puute positus -skenaariossa. Molemmat takaisinottoskenaariot olivat ympäristön kannalta parempia vaihtoehtoja kuin lääkejätteen poltto. Kotitalousjätteen kautta kaatopaikalle sijoittamisella oli kuitenkin selvästi pienempi ympäristövaikutus kyseisen prosessin energian kulutuksen ja resurssien puutteen vuoksi. Sairaalahaastattelun perusteella takaisinotto-ohjelma on toteutettavissa vain sairaalahenkilöstön minimaalisella altistuksella vaarallisille aineille tai henkilöstön vähäisellä vaivalla. Lopuksi, LCA:n herkkyysanalyysi toi esiin sen, kuinka tärkeää on maksimoida laitteen käyttäjien osallistumisaste sen sijaan, että PCBA-kierrätysastetta pyrittäisiin maksimoimaan.

Area patrolling with a swarm of autonomous vehicles is a current research task in the defence and military industries. In order to maximize the area patrolled, the swarm members require decentralized path-planning to ensure both equal division of the patrol area between the swarm members and coverage of the whole area. In this thesis, five decentralized methods for swarm area patrolling is presented. The methods include learning-based methods neuroevolution, deep reinforcement learning and virtual physics optimized with genetical algorithm ,and direct path optimization methods constraint programming and simulated annealing. The thesis evaluates the methods in a custom simulator environment. The direct optimization methods are found to outperform the learning-based methods in both division of the patrol area and providing coverage to a larger area while also providing paths with less obstacles resulting in faster and safer patrolling.

Traditional overhead power transmission lines are designed and manufactured using worst case conditions or scenarios like high solar radiation, low/no wind speed, and high ambient temperature; and this makes them to have a fixed rating (static line rating). The fixed rating of this transmission lines can be optimized to accommodate more loads when wind at high speed cools the line by convection. The convective cooling from the atmospheric air or wind is the main factor affecting the line current carrying capacity (ampacity) which helps the line to accommodate more loads. The extra available capacity can be utilized in the power system to re-duce network congestion and minimize production curtailment of wind power system. This can be only achieved when dynamic line rating technologies are installed on the line to provide real time monitoring of the transmission line characteristics, and also calculate the ampacity of the transmission line which will be needed by the control center (system operators) to know the available allowance the system can still accommodate. This thesis report aims to compare and analyze various Dynamic Line Rating (DLR) technologies available in the market and recommend the best based on technical aspects (measurement accuracy, performance, reliability, efficiency, ease of installation and integration) and business aspect (cost of purchase and installation). This report will also help the reader to identify the classifications, applications, benefits, and drawbacks associated with the various DLR technologies. The importance and benefit of DLR for wind power system integration will be discussed in this report and also, the challenges associated with DLR technology implementation and integration into the power system will as well be discussed. Result showed that Power Donut had the best performance and measurement accuracy when compared to other temperature monitoring technologies, while any of the sag monitoring technologies can be installed depending on the span location, operational voltage, weather condition of the area, network design, and configuration.

Due to the rising demands of energy and decarbonization of the energy sector, use of renewable energy is on the rise. In fact, renewable energy is the future because use of conventional sources of energy does not assure clean environment and we do not have unlimited supply of coal, gas, or petroleum. Among the other renewable sources of energy, solar energy is quite popular and has been proven to be reliable in most of the countries. Photovoltaics (PV) technology has been the most popular technology used to convert solar radiations into usable form of energy. In my thesis, we get a brief overview of the operating principle behind solar PV technology and its history of evolution. The main characterestics involved when the development of PV technologies need to be considered have been discussed. The different PV technologies that exist today have been explained in brief. Different PV technologies have different efficiency rates, and each has its own advantages and disadvantages. The state of the art of the commercially maure PV technologies will be discussed elaborately. In the end, the challenges of PV technologies have been discussed.

Modern mobile networks require high-performance and low-power baseband processing systems. Those digital systems are designed as System-on-Chip (SoC), integrated circuits comprising billions of transistors into a single chip. The baseband processing SoCs are composed of several power-hungry engines such as the Layer-1 processing subsystem. That subsystem performs essential tasks for modern multicarrier and multiantenna techniques. Each task is executed in individual Intellectual Property (IP) blocks, independently developed, and progressively integrated into the subsystem. The most power-consuming functionalities of the subsystem are IFFT/FFT for OFDM symbol generation, decimation for the Physical Random-Access Channel (PRACH) signal extraction, sub-band filtering for mixed numerology carrier support, and Physical Resource Block (PRB) compression and decompression. The convergence of such high-computing processing tasks and multiple technologies into a single chip continuously increases the SoC power dissipation. Therefore, the power consumption is a crucial parameter on SoC design and must be estimated and tracked as early as possible in the design process to mitigate the problem through power optimizations. Nonetheless, the maturity of individual IP blocks at early design stages differs and generally does not include the final intended functionalities, which leads to inaccurate power estimates. The main objective of this thesis is to simulate and model the power consumption of a Layer-1 subsystem which is part of a Digital Front-End (DFE) SoC. The subsystem is a high-performance 4G/5G baseband processing accelerator for Layer-1 in the 3GPP base station functional stack. The subsystem power estimation for different FDD/TDD test cases is calculated using individual IP power simulations in different modes of operation. The baseline IP power simulations were carried out at the Register-transfer level (RTL) and repeated at various design stages. In addition, gate-level simulations were also used in the latest design stage to calibrate the power model. The latest gate-level simulations have more design information; thus, they are considered the closest to the real results and are used to compare the early RTL power simulations and the power model. In the worst case, using the first-round results of RTL simulations and without calibration, the power model produced a mean absolute error of 4.1% compared to the latest gate-level results. However, results also show that error decreases with calibration and as the design maturity progresses. In addition, a simple spreadsheet-like tool was developed to quickly estimate the subsystem power consumption for different test cases and processing capacities, allowing designers, integrators, and system architects to perform estimates without requiring new power simulations for each scenario. Finally, considering the concept of reuse of Intellectual Property (IP) blocks, the power database built serves as an accurate starting point for future similar projects.

Model predictive control (MPC) has gained a lot of attention for power electronic systems during the last two decades. Its ability to control multiple-input multiple-output (MIMO) and non-linear systems, apply constraints on the state, input and output variables, compensate for time delays, and achieve multiple, often conflicting, control objectives with a single control loop makes it well suited for power electronic systems. Challenges in implementing direct MPC in power electronic systems relate to its profound computational burden to solve the optimization problem in real time within a few tens of microseconds. A promising converter topology for medium to high power applications is the modular multilevel converter (MMC). Due to the MIMO nature of the MMC, MPC is a good choice to control the MMC. The possible switching states of the MMC increase exponentially with the number of submodules per MMC arm which further increases the computational burden of the controller. In this thesis, a direct MPC scheme with reference tracking for the MMC is presented and it is validated by simulations for a back-to-back MMC-based high-voltage direct current (HVDC) system with 20 submodules per arm. The controller is capable of achieving low output current total demand distortion (TDD), eliminating the circulating currents and balancing the submodule capacitors while operating at low switching frequency per switching device.

The end-to-end physical layer design of wireless communications based on deep learning algorithms is considered a promising approach since it aims to jointly optimize the transmitter and receiver to adapt to the channel conditions. This end-to-end design is based on the concept of the autoencoder which is a type of neural network (NN) that learns to reconstruct its input at the output. For practical scenarios, the over-the-air (OTA) channel and hardware effects such as carrier frequency offset (CFO) cannot be modeled accurately by mathematical expressions in the training process. This challenge could be overcome by deploying a two-phase training process. Moreover, timing synchronization is essential for continuous transmission schemes in practical systems. In drone communications, the system encounters time-varying Doppler shift, for which different scenarios are considered depending on the variation rate. Training a single model to deal with different scenarios efficiently can be a challenging problem in this research area. In this thesis, first, the implementation and finding the optimum hyper-parameter setting for the basic autoencoder model are investigated. Then, the two-phase training approach is validated using a simulated channel in GNU Radio. Furthermore, the training process of the offset estimator for timing synchronization in continuous transmission schemes is elucidated. Next, the implementation and hyper-parameter setting of the autoencoder model in the orthogonal frequency division multiplexing (OFDM) scheme with the cyclic prefix (CP) are investigated. At last, the OFDM-Autoencoder is studied for drone communication links encountering time-varying CFO. The effect of the time-varying CFO on the received samples is modeled in different scenarios depending on the variation rate. A training approach is proposed by which the OFDM-Autoencoder can handle time-varying CFO efficiently in all Doppler shift scenarios using the same structure. The study of hyper-parameter setting in the basic autoencoder model indicates that improper batch size degrades the performance close to 1 dB for a BLER of 1e−4. In the investigation of the two-phase training process, it has been shown that inaccurate modeling of the real channel in phase I has a significant impact on the performance of the initially trained model which can efficiently improve after the fine-tuning process. While the fine-tuning gain is negligible for low Eb/N0 range, in high Eb/N0 range, it achieves almost 1 dB gain for a BLER of 1e−3. The OFDM-Autoencoder can compensate perfectly for the time invariant CFO by employing CFO compensation NN in the time domain; such that it achieves BLER performance identical to the no-CFO scenario for most of the SNR range. Furthermore, the proposed training approach enables time-varying CFO compensation of OFDM-Autoencoder in almost all Doppler scenarios with the same structure. In the case of high-rate variation, the OFDM-Autoencoder can achieve almost 4 dB performance gain for a BLER of 1e−2 compared to a conventional system.

Kunnossapidon tärkeys on nykyaikana korostunut entisestään ja hyvin johdettuna se on lisäarvoa tuottava toiminto. Kunnossapidolla pystytään vaikuttamaan yrityksen laatuun, tuottavuuteen ja tuotannon tehokkuuteen. Kunnossapidolla on myös suuri merkitys yrityksen kilpailukyvylle, joka on nykyään myös integroitu osa yrityksen toimintaa. Tässä diplomityössä tarkoituksena oli kehittää Satasairaalan olemassa olevaa sähkötekniikan kunnossapitostrategiaa ja selvittää missä kehityksen kohteet ovat, jotta se täyttäisi tarvittavat vaatimukset ja kunnossapitostrategiaa pystyttäisiin hyödyntämään tehokkaammin tulevaisuudessa. Tutkielma alkoi teoriaosuudella, jossa käytiin läpi kunnossapitoa ja kunnossapitostrategiaa yleisellä tasolla. Siitä jatkettiin Satasairaalan lääkintätiloihin ja lääkintätiloja koskeviin vaatimuksiin sekä kerrottiin sairaalan sähkönjakelujärjestelmistä. Tutkielman viimeisimmässä ja tärkeimmässä osiossa olikin sitten tarkoitus kuvata käytännön osuutta ja vastata niihin tavoitteisiin, joita yhdessä Satasairaalan sähkötekniikan käyttöpäällikön kanssa olimme pohtineet. Suurin ongelma nähtiin siinä, että jatkuvien ja nopeaan tahtiin tehtävien muutostöiden sekä muun normaalin arjen pyörittämisessä on erittäin vaikea pysyä.

This Master of Science thesis aims to review and compare 4G Long-Term Evolution (4G) of wireless cellular technology versus Fifth Generation (5G) of wireless cellular technology from different points of view. The main perspectives of comparison are the overall architecture, used frequency bands, frame structures, and frame configurations, the network capabilities of maximum data throughput, and latency theoretically. On the other hand, comparing the field measurements of data throughput and latency, then concluding and originating the reasons behind the mismatching between the theoretical expectations and the obtained values of measurements. The compared cellular network technologies in the theoretical part are 4G, 5G NSA, and 5G SA. In contrast, in the actual measurements, the operated cellular networks are only 4G and 5G NSA. The conducted measurements in this thesis were performed in two environments, Urban and Suburban areas. The propagation environments were indoor, outdoor Non-Line of Sight, and outdoor. The measurements were performed in Tampere, Finland. Because of the continuous deployment of 5G networks and upgrade of 4G networks (because of 5G), three rounds of measurements have been performed. The first round of measurements took sixteen days. The measurements were discarded after checking them because of the upgrading and deployment of networks. The second round of measurements took five days. This round was discarded for the same reasons as before. The third round of measurements took eight days. This round of measurements was successful; therefore, it was considered and progressed. The utilized cellular network in measurement progress was “Elisa”. The 5G phase during the time of measurements was still being deployed, and thus 5G coverage was not available in some locations or times during the measurements. Therefore, more capacity, coverage, and better performance are still expected in the future (5G is not ready yet for typical coverage and expected capacity). OnePlus 8 5G was used as User Equipment (UE) to perform both 4G and 5G measurements. The UE has been forced to operate on 4G mode during the measurements of 4G and on 5G mode during the 5G measurements. Static locations have been chosen to perform the measurements of each of 4G and 5G. The results and their analysis are giving an idea about 4G and 5G cellular networks performance in Urban and Suburban areas with indoor, Non-Line of Sight, and Line of Sight outdoor propagation environments. That idea can be beneficial for understanding the 4G and 5G cellular networks performance and in 4G and 5G performance-enhancing in specific areas or spots, networks planning and deploying of 4G and 5G. The measurements and the scenarios of conducting them can form a foundation for more expanded and complicated scenarios and more intense measurements. The overall results have shown that 5G offers 11 % less latency, 18 % higher upload throughput, and 30 % higher download throughput, than 4G. The overall results have shown that 5G offered an overall 16 % less latency, 22 % higher upload throughput, and 37 % higher download throughput than 4G in the Urban area. The overall results have shown that 5G offered an overall 8 % less latency, 13 % higher upload throughput, and 24 % higher download throughput than 4G in the Suburban area. Overall, the 5G service in outdoor propagation environments was much better than 4G. In comparison, the case is opposite in indoor propagation environments unless the 5G received signal level is high enough to guarantee good 5G service quality and performance at UE (location 11).

Usage of wireless communications has seen a remarkable rise in the past decade. Significant strides in certain areas like Video on Demand and augmented reality, emergence of new inter-net-based services, and rapid increase in number of user-end devices calls for exceptional improvement in wireless network capacity and data rates. To address such needs use of higher frequency bands has been suggested. The unlicensed 60 GHz band with large bandwidth is deemed capable of carrying multi-gigabit transmissions over short distances. This thesis work is intended to analyze the characteristics of 60 GHz channel inside the tram using the channel sounding technique. The measurement locations were divided in two regions based on propagation environment. To characterize the channel, parameters such as path loss, shadowing, delay spread, and Rician k-factor have been reported. In addition to that, analysis on excess loss and propagation paths has also been performed. The results show how channel characteristics vary at different locations inside the tram. Moreover, it has been observed that characteristics of the channel are significantly influenced by propagation environment.

The objective of this work was to investigate the possibility of using the open source tools provided by The Yocto Project, especially the task and build engine BitBake, to replace the old device image toolchain called Imagetools, which is created by Teleste for its train information system devices. While Imagetools mainly use Debian Linux distribution as the base for device images, the build environment created in this work is capable of building a fully working custom Linux distribution named Teleste Sky Blue for Teleste’s embedded device DCU40, which is the main controller unit for Teleste’s train passenger information systems. The work begun by inspecting the Yocto recipes and instructions for DCU40’s processor card by Seco, which is the manufacturer of the card. These recipes covered the GPIO expanders, SPI and I²C. First of all, these few recipes were updated to support the newest stable Yocto Project version 3.1, codenamed Dunfell. Builds were tested by installing them on DCU40’s internal eMMC memory with the live USB flash drive image, which was generated with the BitBake, with network boot and in virtual environments. An automation script was written for pushing the cache items generated by the BitBake builds to Teleste’s company network file share which made subsequent builds faster. In the next phase, more features were added to the build to produce an image which would have the same base functionalities than the "base image" produced by Imagetools. These include kernel and software configurations, and Teleste’s platform packages which enabled a full support for DCU40’s features. The base software of a "base image" includes a Python interpreter with necessary packages, Java Runtime Environment with public and Teleste’s libraries, PostgreSQL with default database, and Lighttpd HTTP-server with Teleste’s Update Manager Web interface. New BitBake recipes were written for Teleste’s platform components and existing recipes from Yocto’s reference distribution named Poky and OpenEmbedded Layer Index were modified to match the existing Imagetools "base image". After the base features of DCU40 were added to the build, recipes were written for the rest of Teleste’s platform components, which are used in customer projects. Customer device images are also created with Imagetools, together with update packages uploaded from the Update Manager. However, with BitBake it is possible to automate the whole customer image creation process so that no other extra steps are needed to be taken in production for the customer project images. Also, the rest of the Imagetools features were added to the build environment, such as fully automated live USB flash drive image creation and VirtualBox image creation. In addition, more features were implemented to the build environment including Qemu virtualisation on command line for automated software tests, network booting of DCU40 with iPXE, and virtual machine images with nested virtualization support for virtual machine development and usage on DCU40. During the work, the environment was used in investigation of DCU40’s processor card’s Intel microcode update performance degradation related to Meltdown and Spectre vulnerability mitigations. Eventually more and more thought and planning was put in to the build environment itself so that it would be scalable and useful on developers PCs to CI servers. The build environment created in this work is a clean and portable Git repository, with documented features which could eventually supersede Imagetools and overcome the challenges and problems it has.

The System on Chip (SoC) field relies on tools and processes. Tools are used for design, automation and verification purposes. Automation tools do repetitive tasks and one of these tasks would be generation of register banks. Register banks are fast memory of SoC modules and each SoC module requires their own set of registers to suit module’s needs. Register bank generation tools enable developers to quickly generate registers for a SoC module according to a register configuration file. In this thesis project there is an existing register generator tool flow that uses IP-XACT as intermediate file format. This IP-XACT file is interpreted and VHDL is generated based on its’ data. The previously developed tool that does the conversion has become very fragile to changes and its’ programming language differs from the rest of the flow. This thesis describes the update to the IP-XACT to VHDL flow. A database is planned to be used as an intermediate format between IP-XACT and VHDL. A database approach would enable easy modifications, big and small, and the database is constructed in such a way that IP-XACT can be regenerated from it. Tool was developed for the flow and is available alongside the old implementation. The development was successful since the tool is able to transfer the information from IP-XACT file to database losslessly and then generate a VHDL file according to a register description from the IP-XACT file stored in the database. The tool has gone through verification and continues to be in development for extended functionality. Otherwise, the tool is in support mode and provides its’ intermediate database for other flows.

Power semiconductors play an important role in the fast development of power electronic de-vices. During last several decades power semiconductor switches have gone through evolution from thyristors and bipolar transistors to metal-oxide-semiconductor field-effect transistors (MOSFET) and insulated-gate bipolar transistors (IGBT). Traditionally these devices have been implemented by using silicon (Si). On the other hand, Si-based technology is quite mature and major innovations with them are hard to achieve. Wide bandgap materials (WBG) such as silicon carbide (SiC) and gallium nitride (GaN) have become dominant field of study during the 2010s. They are showing outstanding electrical properties compared to older Si-based technology and are believed to be the next revolutionary generation of power semiconductors. One major field of power electronic devices are variable-frequency drives (VFD) that control the rotation speed of an electrical motor. In this thesis the usage of SiC MOSFET in the line and motor converters of VFD is studied. Studied VFD is used to control the rotation speed of an ele-vator motor and thus the speed of an elevator car. In the original device the line and motor con-verters are implemented with Si IGBT modules and during the thesis these modules are replaced with SiC MOSFET modules. Much lower power losses in the semiconductor switches are believed to be achieved because of much lower switching losses of the SiC MOSFETs. Power losses of the device are first modelled and measured with Si IGBT modules. Based on these measurements about 1 kW power losses takes place in the device at the nominal motor current, 24 A. The distribution of these power losses is analytically modelled. Based on this mod-elling, about 46 % of the total losses are taking place in the Si IGBT modules in the line and motor converter and 19 % of the losses are taking place in single-phase inductors used in the LCL-filter of the device. Power losses taking place in these inductors can be reduced by increasing the switching frequency of the line converter which enables the usage of lighter filtering. Lighter filter-ing means that lower inductance is required, and the number of turns can be reduced in these inductors. Because of lower switching losses of SiC MOSFETs, switching frequency of line con-verter can be increased without dramatically increasing the switching losses of the SiC MOSFETs. Power losses of the device are modelled with SiC MOSFETs and based on models about 28 % power savings can be achieved with SiC MOSFETs. Power losses of the device are measured with SiC MOSFETs and was seen that power losses have decreased even more than was as-sumed, about 31 %. Next, the gate voltage of the SiC MOSFETs is increased to 20 V from the original 16 V that was used with IGBTs. With this change, even higher power savings are as-sumed to be achieved because on-resistance of MOSFETs should decrease with higher gate voltage leading to lower conduction losses and switching time of the MOSFETs should decrease with higher gate voltage leading to lower switching losses. Losses are again measured and is seen that the losses are higher with increased gate voltage. Current and voltage waveforms of MOSFETs are measured with oscilloscope and is seen that higher gate voltage causes much higher current oscillation which causes additional losses in the inductors cancelling out the lower conduction losses of SiC MOSFETs. Five new variants of single-phase inductors are designed for switching frequencies between 10 and 30 kHz. With these new variants about 1,4 – 6,6 % additional power savings are assumed to be achieved with higher switching frequencies. Losses are measured with all new variants and was seen that maximally about 1,4 % power savings is achieved at 14 kHz switching frequency.

Changes in the global energy infrastructure have increased the quantity of renewable clean energy. Solar thermal energy is plentiful in the summer and limited in the winter like here in Finland where the lattitude is high. This literature review tries to define seasonal solar thermal energy storage utilizing multiple storage strategies. The solution is thermal energy storage (TES).It collects energy in the summer, stores it for the winter, and then recovers it to meet heating needs or vice versa. There are numerous underground TES technologies that might be deployed.Lithiim ion battery and PCM are such technologies existing today.This study's aim is to compare different TES technology, comparing different TES materials (Ie,latent, Phase change Materials, Thermo Chemical Materials), future TES trend in Finland etc.

Laivan sähköverkko on moniulotteinen sähkönvoimajärjestelmä, joka eroaa monin tavoin julkisesta sähköverkosta. Sähköverkon pitää pystyä toimimaan itsenäisesti merellä ja siinä tuotanto tapahtuu lähellä kulutusta. Yksi tärkeimmistä laivan sähköverkon laskelmista on sähköbilanssi eli sähkönkuormituslaskelma. Sähköbilanssin muodostaminen on tärkeä osa laivan suunnittelua, sillä oikein laskettu bilanssi vaikuttaa huomattavasti laivan kaapeleiden mitoitukseen ja kustannuksiin. Tämän työn tarkoituksena on selventää laivan sähkösuunnittelua, sähköbilanssin laadintaa ja esittää kehitysehdotuksia tulevaisuutta varten. Työn teoriaosuudessa selvitetään laivan sähköverkon rakennetta ja laivan suunnittelun etenemistä. Teoriaosuudessa esitellään myös laivan automaatiota, tehonhallintajärjestelmän toimintaa ja sen päätehtäviä sekä yleisesti laivan bilanssilaskentaa. Työn yhteydessä toteutettiin Rauma Marine Constructions Oy:n rakentaman Aurora Botnian sähköbilanssi. Sähköbilanssin tekemistä analysoidaan ja havainnoidaan bilanssin laadinnan aikana ilmenneitä ongelmia ja haasteita. Lopuksi esitetään kehitysehdotuksia bilanssin tekemiselle tulevaisuudessa. Työn edetessä tuli ilmi, että suurimpia haasteita bilanssin laadinnassa on alkutietojen puute sekä tiedon perustuminen kokemukseen eikä niinkään mittaustuloksiin. Laivasuunnitteluprosessin ekosysteemiin tehdään kehitysehdotuksia. The ship’s electrical grid is an interesting electrical power system that differs in many ways from public network. The electrical grid must be able to operate independently at sea where consumption is close to production. One of the most important calculations of the ship’s electrical grid is the load balance. It is necessary to make the load balance correctly while it has a significant effect on the sizing and costs of the cables in the ship. The main purpose of this thesis is to clarify the electrical design of the ship, the load balance and to present development proposals for the future. The theory of the thesis clarifies the structure of the ship’s electrical grid and the ship’s electricity grid design. The theory also introduces ship automation, the operation of the power management system and its main tasks as well as the general principles of the load balance calculation. In connection with this thesis the load balance of Aurora Botnia, built by Rauma Marine Constructions Oy, was also made. The compilation of the load balance is analyzed and the problems and challenges that appeared during the project are identified. Finally development proposals for making the load balance in the future are presented. As the project progressed, it became clear that the biggest challenges in compiling the load balance are the lack of the initial data and the fact that the information is based on experience rather than measurement results. Development proposals are made for the ecosystem of the ship design process.

The incorporation of Distributed Energy Resources (DER) is growing in many power systems globally. This incorporation presents a significant challenge to the maintenance and service of new power systems, leading to a growing need for proactive distribution network services. Congestion is an issue that is rapidly emerging in distribution grids due to the upward increase penetration of DG in distribution systems. The DSOs are also obligated to evaluate and enhance their maintenance costs by implementing smart grid features and functions to minimize investment. Out of a variety of solutions, congestion control is amongst the most optimistic methods for solving network problems. Congestion control systems have historically been handled at the level of the transmission grid. However, with the extensive utilization of Distributed Generators (DGs) and the anticipated extreme loading conditions, the control technique would have to be extended to the distribution network also. Methods for controlling congestion in distribution systems have recently gained the attention of academics and others operating in the electric grid domain. A variety of techniques are being extensively explored to overcome the complexities of direct switching behaviour. However, non-market-based interventions wouldn't be the most successful and cost-effective option. Besides that, smart strategies that harness the flexibilities of users need to be built to leverage existing grid infrastructure effectively. Flexibility services can enable network operators to always resolve grid restrictions, sustain stability and quality of service, and optimize the integration of distributed power sources. The implementation of a local flexibility market (LFM) would enable flexible trade to be carried out by both processing and consumption units at the distribution stage, ensuring access to markets to DERs, a Distribution System Operators Support Tool (DSOs), and a valuable source for energy providers. The concept of the study is to resolve congestion in distribution systems through market processes, particularly the local flexibility market. This study provides a detailed analysis of four pioneering scalable business projects: Piclo Flex, Enera, GOPACS, and NODES. Attempts have been devoted to present a comprehensive summary of market architecture, which includes the framework, participation, placing bids, and clearing processes, of the local flexibility market initiatives produced in recent years. However, system operators need to cooperate for ensuring reliable, consistent, and cost-effective utilization of scalable facilities, since these tools can theoretically be used both locally and throughout the grid. This paper gives a comprehensive overview of synchronization schemes in power networks between transmission & distribution power grid, with a specific focus on the implementation of balancing as well as congestion control services.

The series compensation has been used at the main power transfer routes between northern and southern Finland, as well as in connections to Sweden, to increase the transmission capacity. In certain conditions the interaction between series compensated network and wind power plants may cause unstable subsynchronous oscillations. In Finland many new wind power generation sites will be built in the vicinity of the series compensated network, thus increasing the risk of subsynchronous oscillation phenomena. The subsynchronous oscillations can cause a disconnection of significant amount of wind power production and possibly damages in the wind turbines or series capacitors. This master’s thesis investigates the amount of potentially disconnecting wind power production capacity in the Finnish transmission system due to the subsynchronous oscillation phenomena and develops methods for validating the need and functionality of the subsynchronous oscillation protections in the wind turbines. The doubly-fed induction generator based (Type-3) wind turbines are identified to have a significant risk of causing undamped subsynchronous oscillations, while the full power converter based (Type-4) wind turbines are found to be generally immune to subsynchronous oscillation phenomena. The immunity of a single manufacturer Type-4 wind power plant model is also validated in the thesis. The maximum amount of potentially disconnecting wind power production capacity in single substation is defined using the estimated amount of production capacity from wind power plants with Type-3 wind turbines. The conservative estimations show that the highest amount of potentially disconnecting production capacity could be in range of 340–775 MW in 2022, 520–1225 MW in 2027 and 850–2225 MW in 2030. Fortunately, the amount of disconnecting wind power is likely not as great as the conservative estimation leads to believe, for example due to the risk of undamped subsynchronous oscillation being higher when the output power of the Type-3 wind turbine is lower. Defining more precise estimations will require additional studies in the future. The method for validating the need of subsynchronous oscillation protection in Type-4 wind turbines is developed in the thesis. The proposed method consists of three steps: 1) validation of the immunity to subsynchronous oscillations, 2) defining the worst-case scenario using parallel connected generic Type-3 wind power plant, and 3) discussions with the wind turbine manufacturer. It is proposed that if the investigated Type-4 wind turbines are not found to cause undamped subsynchronous oscillations itself and can withstand the worst-case subsynchronous oscillations caused by another nearby wind power plant, the specific subsynchronous oscillation protections should not be mandatory for the investigated wind turbine model. The method was illustrated on a single manufacturer Type-4 wind power plant model. Validating the functionality of Type-3 wind turbine subsynchronous oscillation protection can be performed for example by first injecting subsynchronous voltage or current of certain frequency on top of the fundamental voltage or current in the wind turbine terminal, and by varying the magnitude and the frequency of the injected current or voltage. Second, the selectivity of the protection should be more thoroughly investigated using another parallel connected Type-3 wind power plant in order to validate that the wind turbines that are most significantly causing the oscillations are disconnected first in the subsynchronous oscillation event. Sarjakompensointia on käytetty Suomessa kasvattamaan sähkön siirtokykyä pohjoisesta Suomesta eteläiseen Suomeen, sekä Ruotsin vaihtosähköyhteyksillä. Sarjakompensoidun verkon ja tuulivoimaloiden välillä on mahdollista syntyä alisynkronista vuorovaikutusta, joka voi aiheuttaa vaimentumattomia alisynkronisia värähtelyitä. Tulevaisuudessa huomattava määrä tuulivoimaa tullaan liittämään Suomessa sarjakompensoidun verkon läheisyyteen, mikä kasvattaa merkittävästi alisynkronisen vuorovaikutuksen riskiä. Alisynkroniset värähtelyt saattavat aiheuttaa merkittävän määrän tuulivoiman irtoamista, sekä mahdollisesti myös vaurioita tuuliturbiineissa tai sarjakondensaattoreissa. Diplomityössä arvioidaan alisynkronisten värähtelyiden takia irtoavan tuulivoimatuotannon määrää Suomen kantaverkossa, sekä kehitetään menetelmiä, joilla voidaan määrittää tuuliturbiineja alisynkronisilta värähtelyltä turvaavien suojauksien tarvetta sekä odotettua toimintaa. Kaksoissyötetyllä epätahtigeneraattorilla toimivalla tyypin 3 tuuliturbiinilla on tunnistettu olevan merkittävä riski joutua alisynkroniseen vuorovaikutukseen sarjakompensoidun verkon kanssa, johtaen tuuliturbiinin irtoamiseen verkosta. Täyden tehon taajuusmuuttajalla toimivat tyypin 4 tuuliturbiinit on todettu tavallisesti olevan immuuneja alisynkronisille vuorovaikutuksille. Yksittäisen tyypin 4 valmistajamallin immuniteetti validoitiin työssä. Alisynkronisten värähtelyiden takia tietyllä sähköasemalla mahdollisesti irtoavan tuulivoiman maksimimäärä arvioidaan asemalla olevien tyypin 3 tuulivoimaloiden tuotantokapasiteetin perusteella. Konservatiivisten arviointien perusteella alisynkronisen vuorovaikutuksen seurauksena suurin irtoava määrä tuulivoimatuotantoa voisi olla 340–775 MW vuonna 2022, 520–1225 MW vuonna 2027 ja 850–2225 MW vuonna 2030. Toisaalta pohdintojen perusteella todennäköisesti irtoava tuulivoiman teho olisi kuitenkin todellisuudessa reilusti alle konservatiivisen arvion johtuen esimerkiksi siitä, että tyypin 3 turbiinin riski joutua vuorovaikutustilanteeseen on suurempi mitä alhaisempi turbiinin tuottama hetkellinen teho on. Jatkotutkimukset ovat tulevaisuudessa tarvittavia tarkempien arvioiden selvittämiseksi. Tarve alisynkronisilta värähtelyiltä suojaavalle suojausfunktiolle tyypin 4 tuuliturbiineissa voidaan määrittää työssä kehitetyllä menetelmällä. Ehdotettu menetelmä koostuu kolmesta toimenpiteestä: 1) tyypin 4 laitoksen immuniteetin varmistaminen, 2) pahimman tilanteen määrittely käyttäen rinnalle kytkettyä geneeristä tyypin 3 tuulivoimalaitosta, ja 3) keskustelut tutkitun tyypin 4 tuuliturbiinin laitevalmistajan kanssa. Työssä ehdotetaan, että jos tutkittu tyypin 4 tuuliturbiini ei aiheuta alisynkronisia värähtelyitä ja kestää geneerisen tyypin 3 tuulivoimalaitoksen aiheuttaman pahimman vuorovaikutustilanteen, suojausfunktiota alisynkronisia värähtelyitä vastaan ei tarvitsisi vaatia kyseiseltä tuuliturbiinimallilta. Kehitettyä menetelmää käytettiin työssä yhden tyypin 4 valmistajamallin validointiin. Tyypin 3 tuuliturbiinin suojauksen toimintaa voidaan validoida syöttämällä alisynkronista virtaa tai jännitettä tuuliturbiinin terminaaliin, ja tutkimalla suojan toiminta-aikaa eri syötetyn virran tai jännitteen voimakkuudella ja taajuudella. Suojan selektiivisyyttä täytyy kuitenkin tutkia tarkemmin käyttämällä vähintään toista tyypin 3 tuulipuistomallia rinnalla, ja tutkimalla toimiiko suojat oikein, kun jompikumpi laitoksista pääasiassa aiheuttaa alisynkroniset värähtelyt.

Industrial areas are vast and have massive movement going in and out. Knowing who is in the area and where they are approximately located is one of the main goals in access control. To achieve this goal, the industrial area has to have dedicated infrastructure for it. The problem arises from the expensive investments and lack of easy scalability. This work describes a prototype system’s design and research based on computer vision and mobile devices that track people in a restricted industrial area. Using computer vision with IP cameras is more affordable to cover bigger areas and easier to scale the infrastructure to match the needs. The prototype system consists of two IP cameras that send video surveillance feed to the server to be analyzed and mobile devices that send sensor data from a user. The implemented system consists of two Xiaomi Redmi Note 8T phones as IP cameras that send surveillance feed wirelessly to Python-server to be processed. The server’s convolutional neural networks recognize a person from the image and aim to re-identify the person during the whole visit in the area. The person’s movement is followed on a map, where the location on the image is projected upon. If the person is not detected from the image, the location’s estimation is sought using the same person’s mobile device. By fusing these two tools, a more robust tracking system is created. Besides these tools, also an option to use satellite tracking in the system was researched. The system was tested by finding out if the system can operate well in the areas where the satellite tracking was having issues and if the satellite tracking can identify a person seen by the system’s cameras. Besides comparing the proposed system to the satellite tracking, the tracking visually and dead reckoning was analyzed. Finally, the system’s capability to follow multiple people was tested. The testing results indicate that it is possible to track multiple objects accurately by using visual detections. Besides visual tracking, it is also possible to get an estimated position based on dead reckoning when the object is not visually detected. The satellite tracking cannot follow the person properly in challenging environments, but it can be used to identify the person in the open areas.

Multi-User Multiple-Input Multiple-Output (MU-MIMO) scheme serves several users simultaneously using the same time-frequency resources and it achieves a larger capacity comparing to single-User MIMO. Spatial multiplexing requires beamforming techniques and the weights are adjusted by linear precoding to mitigate inter-user interference. A possible method in 5G New Radio is Eigen-based Zero-Forcing (EZF) beamforming which is optimum in terms of computational complexity. This thesis work aims to model a hardware accelerator for EZF downlink beamforming at the base station transmitter. Additionally, a computationally-optimized version of EZF beamforming is also modelled. Hardware implementation requires fixed-point modeling of both beamforming methods and the models are developed using 16-bit data accuracy. System performance is compared between floating-point and fixed-point models for both EZFbeamforming methods. The new data format results in a negligible performance loss, which indicates a fair tradeoff between implementation complexity and system performance.

Due to its economic and environmental advantages, solar photovoltaic (PV) energy has attracted significant interest in recent decades. In addition, thanks to the enormous potential of solar energy, today, photovoltaic (PV) energy is one of the fastest-growing clean energy resources. Thereby, the number of grid-connected photovoltaic (PV) systems installations is constantly growing worldwide than ever before. Commonly, solar photovoltaic (PV) power plants are comprised of hundreds or thousands of solar PV modules, which represent the main component for PV power production. However, due to various types of stresses, PV modules might be subjected to different kinds of failures and defects over their lifetime. Thus, the out-put power of the PV power plant might be dramatically reduced. The most common types of PV modules failures are snail trails, cracked PV cells, delamination, bypass diode failure, hot spots, EVA degradation, short-circuited sub-string, etc. Therefore, regular inspection is essential to maintain the optimal efficiency and energy yield of the PV systems. Different techniques are used for the detection of PV modules defects and failures. The most known inspection techniques are I-V curve measurement, electroluminescence (EL) imaging, fluorescence imaging, and infrared thermography. The conventional manual inspection methods such as visual inspection and I-V curve measurement are time-consuming, inaccurate, and require significant human work. Furthermore, some of the inspection techniques are applicable only to identify specific PV module defects and are not helpful for other defects types. In recent years, the infrared thermography technique has become increasingly popular for inspection defects and failures of PV systems. This technique is fast, contactless, and cost-effective. In this technique, defective PV modules can be detected by infrared camera depending on the temperature deviations of the modules. In this respect, unmanned aerial vehicles (UAV) or drones equipped with thermal infrared imaging have become a powerful technique to detect and identify the precise location of detective cells and PV modules in PV systems. In addition, this technique can be carried out under real operating conditions of the PV system. Moreover, applying drone thermography technology for PV systems inspection saves time and reduces maintenance costs compared to the traditional inspection methods. The main goals of this thesis are to explore and evaluate the use of aerial thermography technology to detect possible PV modules failures and defects at Tampere University Solar PV Power Research Station. This thesis was carried out in cooperation with Cleaner Future Oy. DJI Mavic 2 Enterprise Dual was used in this investigation as an inspection tool. The drone has dual infrared thermal and visual cameras. The practical measurements were carried out on 12th and 13th of May 2021. The thermographic and visual images of PV modules are captured during the measurements and subsequently extracted from DJI remote controller for further analysis. In this investigation, the achieved results showed that several defects and failures were detected by thermal drone camera, such as hot spots, EVA discoloration, and ac-cumulation of soiling. Finally, the study results have proven that the DJI Mavic 2 Enterprise Dual with its thermal and visual cameras was helpful and reliable to identify possible failures of PV modules at Tampere University Solar PV research power station.

Advancements in power electronics have led to the growing number of applications of DC distribution multi-converter systems in recent years. The dynamics and stability of multi-converter systems can be conveniently analyzed using methods based on the evaluation of DC network bus impedances. Therefore, efficient and fast wideband methods for measuring the frequency-responses of converter impedances as part of the bus impedance calculation are needed. The pseudo-random binary sequences (PRBS) are highly suitable broadband excitations for converter impedance identification due to many attractive properties such as easy generation, controllable frequency-domain parameters and low measurement time. The thesis work reviews the broadband methods for frequency-response measurements of a multi-converter network using PRBS, and provides studies of DC distribution systems and their stability analysis methods. A simulation approach and a practical experiments are presented in the work to verify the reviewed measurement techniques. The benefits of using binary excitations in power converter impedance estimation were successfully verified. In addition, some of the limitations and special considerations with the methods were briefly discussed. These limitations included the PRBS’s amplitude design tradeoff and its sensitivity to environment noise disturbances.

Millimetre-wave (mmWave) is an extremely valuable sensing technology for the detection of objects and providing the range, velocity, and angle of these objects. A mmWave radar, having synergies with the multi-beam light detection and ranging (LiDAR) and cameras, has been con-sidered as a must-have sensor in the connected and autonomous vehicles (CAV) in the future intelligent transportation systems (ITS). Besides the traditional target detection and ranging functions, the mmWave radar is expected to perform more intelligent tasks to improve road safety, for example recognizing the targets, especially the vulnerable road users like pedestri-ans and cyclists. mmWave radars are also used in indoor environments due to its high capabil-ity of working in low visibility conditions, such as smoke and debris. mmWave radar can provide the exact location of the human presence in the indoor environment with very high accuracy. The first part of the thesis addresses the radar basics and principles, followed by a detailed discussion on FMCW radar. Also, the first part describes the micro-Doppler (µ-D) in the radar system. The second part of the thesis concentrates on the machine learning basics followed by the detailed discussion on the convolutional neural networks (CNN), recurrent neural networks (RNN). The third part of the thesis describes a simulation study of the µ-D signatures of the pedes-trian and cyclist based on mmWave vehicle radar and investigates the recognition capabilities through both the CNN, RNN and mixed convolutional and recurrent approach respectively. The result demonstrates the usability of the mmWave radar µ-D information and complementary with the video and laser data streams in the CAV auto-piloting. A paper ‘’Shallow Neural Net-works for mmWave Radar Based Recognition of Vulnerable Road Users’’ has been published in the IEEE Xplore with this simulation study. The fourth part of the thesis concentrates on the experimental study of an object (human) detection in the indoor environment by using the Texas Instruments mmWave RADAR module. The experimental study results show the target movement in real-time by azimuth-static heatmap, range-doppler heatmap, and range-profile. The acquired data from the experiments are analyzed and demonstrated in the X-Y scatter plot which gives the analytical view of the target (human) movements.

The fifth-generation (5G) cellular network technology standard is bringing massive improvements and many new innovative features in cellular communications and 5G new radio (NR) based positioning is among them. Traditional Global Navigation Satellite System (GNSS) based positioning provides adequate positioning accuracy in outdoor environments but struggles where direct Line of Sight (LOS) communication with the satellites is not possible especially in indoor environments. This new 5G NR based positioning is a promising approach to improve the positioning accuracy in both indoor and outdoor environments. In order to implement this new positioning technology, either a dedicated reference signal for positioning could be introduced or existing reference signals could be utilized to carry out additional positioning responsibility. In our work, we have explored the possibility of availing these existing reference signals for positioning. At first, we have reviewed different wireless communication based positioning systems. Next, we have studied the time and frequency domain resource allocation of uplink and downlink reference signals. After that, we have analyzed and compared the performance, and geometrical influence of the reference signals for Time of Arrival (TOA) and Angle of Arrival (AOA) based positioning technique and demonstrated that these existing reference signals might be capable of positioning responsibility without introducing a dedicated positioning reference signal.

Increasing the usage of renewable resources makes the electricity market important in all countries. Day-ahead and intraday electricity markets play an important role in the electricity market all over the world. Trading on day-ahead markets happens on one whole day before real-time and all participants in the market buy and sell by relying on their estimations on this market. They have the ability to correct their transactions on the intraday market which closure time is just one hour before real-time. In this thesis, intraday and day-ahead electricity markets in Nordic countries, Germany, United Kingdom, Australia, and the USA have been studied. Various viewpoints of these two markets in selected countries are pursued. Introducing definitions, the impact of the type of electricity generation, energy storage, and demand response have been studied on the electricity market in each country. Extracting day-ahead prices and electricity generation and production from August 2019 to August 2020 is studied in this thesis. Comparing day-ahead electricity prices in all selected countries in one year from August 2019 to August 2020 has done. Intraday electricity market prices have been extracted for July for Nordic countries and Germany. After the study on the day-ahead and intraday electricity market, it is realized that a lack of balance between supply and demand is one of the factors that affect electricity prices in both intraday and day-ahead prices. Importing electricity from adjacent countries enhance day-ahead and intraday prices. A high share of hydropower generation causes smoothness and reduction in short term prices in both day-ahead and intraday markets. A high proportion of wind generation boosts intermittency in both electricity production and market prices. Increasing usage of renewable energies decreases average day-ahead prices in all selected countries from August 2019 to August 2020. It is also concluded that day-ahead and intraday electricity prices are relevant to each other but intraday prices mainly have higher values with more fluctuation.

The Thesis covers the comparative study of various Beamforming algorithms for mm-wave which are based on Hybrid MIMO systems. The simulation results based on MATLAB has been shown and compared.

In the past few years, the use of smart devices and the amount of data traffic have been increasing significantly as more and more practical applications using wireless networks were being developed. Hence, machine-type communication (MTC) becomes an important use case for current and future wireless technologies. It covers a wide range of usage areas, for example, industrial automation, smart agriculture, and personal healthcare. This thesis focuses on the application of MTC for autonomous robotics, especially in maritime environments. To minimize the human's interaction on operation, the unmanned offshore system requires an inter-connectivity among the vehicles to exchange telemetry messages, sensor data and to stream surveillance video to a ground station. It leads to a demand for a wireless connection, which works without session interruptions, and provides high data rate, and covers a wide range. Hence, this thesis aims to develop a high-speed long-range communication solution for autonomous maritime operations. To achieve that purpose, a system of directional radio interfaces utilizing IEEE 802.11 Wi-Fi is designed and implemented on three core components of the offshore system: ground control, Unmanned Surface Vehicle, and Unmanned Aerial Vehicle. Each subsystem incorporates mechanical structures and motors, networking devices, and electrical components to form a functional communication solution. In addition, a beam-steering algorithm is developed and implemented for directional radio interfaces. Then, the system is tested in practice and the performance is evaluated in terms of throughput and received signal strength. Moreover, the results are compared with reference theoretical radio propagation models. Here, the details of the system implementation, appropriate tests, and analysis are summarized, evaluated, and discussed.

The deployment of the ultra-dense network in next generation 5G new radio (NR) offers better network capacity and higher data rates. However, the ultra-dense network also causes numerous interferences, such as inter-cell, intra-cell, and inter-user interference. Interferences degrade SINR performances. Furthermore, the next generation 5G NR also suffers in higher path loss which degrades the SNR performances. On the other hand,5G networks will enable high accuracy positioning that can be leveraged to design and optimize wireless networks. In this thesis, we utilize this location information feature of 5G NR for managing the interference. Moreover, different existing interference mitigation approaches are described as background information of interference management. In this thesis beamforming technique has been considered to achieve higher location accuracy and to compensate the path loss. The aid of using beamforming is to achieve the higher antenna gain which enables to steer the transmit signal directly towards the desired user. The simulation result shows that the beamforming technique by using multiple antenna arrays significantly improves the SINR performance along with the SNR performance.

A sensor acts as a connecting medium between the physical world and electrical devices. Based on the power source, there are two types of sensors: active and passive. The passive sensor does not require any direct power source, and it is a less expensive device. Radio Frequency Identification (RFID) is a low-cost, reliable, and fast technology that uses radiofrequency to track down objects and their position. Passive ultra-high frequency (UHF) RFID tags are fast in object tracking, which can operate from several meters distance. To activate the passive tags it required the radio frequency from the RFID reader. Passive UHF RFID tags are extensively used in supply chain management, object tracking, etc. Due to low power data transmission capability, it is used in wireless sensing technology. Electronic waste is one of the leading causes of environmental pollution. In this thesis, the main goal was to implement and test a low-cost, environment-friendly moisture sensor. We manufactured passive UHF RFID tag on low-cost materials, i.e., commercially available dishwashing cloths as substrates. Three different substrate materials were used for moisture sensor fabrication. By using conductive thread and embroidery techniques, the moisture sensors were fabricated. In cases where hand stitching methods were complicated, the embroidery machine was used to fabricate the moisture sensors. For moisture testing, two methods were applied: submerging in water and spraying water. The soluble thread was used to give a circular shape to the moisture sensor tags to observe the bending effect and the substrate's shape-changing tendency after the moisture test on the sensor tags. In this thesis, mainly, three tests were performed to observe the moisture sensor tags' performance in different conditions. Firstly, all the sensors' tags were tested for observing the bending effect on the substrate materials. It was observed that all the materials had similar bending effects, and their read range decreased due to the increase of bending on the sensor tags. Secondly, moisture sensor tags of all the three materials were tested during initial dry, wet, and redried conditions without bending the moisture sensor tags. When redried from the wet condition, the moisture sensor tags' read ranges were improved but could not reach the level of initial dry condition. Compared to all the three substrate materials of moisture sensor tags, Material-2 showed better performance after the moisture testing on the tags. Finally, the moisture sensor tags were tested in a combination of bending and wet conditions. All the tags were tested in two different positions like sidewise bending and hanging from the top in bending condition. In both cases, Material-2 demonstrated better performance when compared to the other two materials. To conclude, though all the moisture sensor tags showed sensing properties within the UHF RFID band, for moisture sensor tag development, “Mikrokuituinen Iisi sieniliina” (Material-2) was better of the three materials, whereas “Talousliina 3m” (Material-3) is the least preferred. Keywords: RFID, UHF, Passive tags, Dishwashing cloth, Moisture sensor The originality of this thesis has been checked using the Turnitin OriginalityCheck service.

The emerging cellular wireless networks of the fifth-generation (5G) are intended to offer higher data speeds, increased quality of experience (QoE) for end-users, reduced end-to-end latency, and lower energy consumption. 5G wireless technology will cover a wide range of use case scenarios from enhanced mobile broadband (eMBB) to ultra-reliable low-latency communications (URLLC) and massive machine-type communications (mMTC). Cell search and synchronization are the initial requirements for all the wireless communication systems to establish an active link between the user device and the base station. In 5G new radio (NR) systems, User Equipment (UE) performs the initial cell search and synchronization for a base station to complete the downlink (DL) synchronization. The primary synchronization signal (PSS) and the secondary synchronization signal (SSS) are the two synchronization signal which are used to achieve the initial cell search and synchronization along with decoding the data in the physical broadcast channel (PBCH). To connect a UE to the network, uplink (UL) synchronization is also necessary. The random access procedure is performed by the UE for the UL synchronization and Radio Resource Control (RRC) connection. This thesis focuses on the synchronization process and the 5G NR radio access procedure. We study the existing algorithms for time and frequency synchronization. A simulation on downlink synchronization is performed considering the analysis of the broadcast channel (BCH) detection probability by using MATLAB 5G toolbox.

Electricity is a commodity, which has many different attributes from other products because of its unique features. It needs a special infrastructure for production, transportation, and consumption. In this thesis, the electricity system is discussed in two subsystems. The flow of electricity happens in the technical subsystem, and monetary value is discussed in the economic subsystem. Here is an attempt to do a comprehensive review of three different marketplaces: AEMO in Australia, CAISO in California, and Nord Pool in Nordic countries based on literature review and available public information. In these marketplaces, there is continuous or upcoming reform of the energy system, which can be strengthened by integrating different perspectives from current markets. Characteristics for a successful electricity market are also proposed at the end of the thesis. Currently, CAISO has a centralized wholesale energy market, while Nord Pool and AEMO have also decentralized properties. The critical issue with the centralized CAISO market is that they don’t have intra-day pricing that can be updated continuously when the renewable generation changes. Whereas Nord Pool and AEMO with their decentralized intraday market, has the flexibility to adjust the price according to renewable energy production as close to real-time. This iterative intra-day trading can address the coordination problem related to wind and solar power generation. The downside is that there is a risk of network constrain, which can be improved by analysing the network in more detail. The limitation of this study is using only three marketplaces where in the future it can be extended to more marketplaces