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This paper presents the use of a radial basis function artificial neural network to estimate sensor readings exploring the analytical redundancy via auto-association. However, in order to guarantee optimal performance of the network, the training and optimization processes have been modified. In the conventional training algorithm, even if a stop criterion, such as summed squared error, is reached, one or more of the individual performance metrics, including: i) accuracy; ii) robustness; iii) spillover and iv) filtering of the neural network, may not be satisfactory while validating sensor measurements. Essentially, the proposed modification in the training algorithm is based on seeking to ensure that one or more of the metrics are met. This paper describes the proposed algorithm including all of its mathematical foundation. Afterward, a data set of a water injection pump for an oil and gas processing unit was used to train the RBF network using the conventional and the modified algorithm, and the performance of each was evaluated. Furthermore, the AAKR model is applied to the same dataset as a quality reference parameter. Finally, a comparison analysis of the developed models is presented for each of the performance metrics, as well as for overall effectiveness, demonstrating that the main advantage of the proposed approach is to obtain the estimation results equivalent or superior to the AAKR with shorter runtime and the disadvantage of having higher complexity during the model training.

Transportation electrification is gaining notoriety in recent years as to fulfill the aim of reducing the fossil fuels consumption and to increase energy efficiency. Accordingly, integrated starter alternator is a compelling method to convert conventional vehicles into hybrid ones. A deal of benefits can be reached by using ISA systems. In general, it provides vehicles performance enhancement and also reduces fuel consumption. This paper aims to present simulation results and preliminary experimental achievements with a power electronics-based prototype driving a permanent magnet synchronous machine (PMSM). The ISA operation is demonstrated throughout providing cranking torque and assistant torque for constant power and constant torque conditions and afterward the generation mode. Details of the hardware design and control strategies, which include an ADALINE neural network for properly find the mechanical position and the application of a metaheuristic technique to tune the controllers of the motor control, have been also addressed.

This article presents a study of the sampling rate effect on electrical power measurements whose definitions are based on the Conservative Power Theory (CPT). The definitions of active power and reactive power of the CPT were applied in the MATLAB® software by varying the sampling rate and using a digital power meter as a reference. The measurements were performed in scenarios with linear and non-linear loads. Due to the usage of an integral in the CPT calculus, an error was verified associated with the reactive power being inversely proportional to the sampling rate. From the present study, it is possible to conclude that depending on the sample rate, the errors associated with the reactive power measurements are unacceptable and make the CPT implementation unfeasible. The results also presented effective information about the minimal sampling rate needed to make these errors neglected and to assist in choosing suitable microprocessors for the digital implementation of the CPT. It is worth mentioning that this paper was limited to assess how accurate the measurements of active and reactive powers were and important to highlight that the CPT has the additional contribution of dealing with distortion currents and consequently new portions of powers. For the latter, the influence of sampling rate may be crucial and new lines of investigation are motivated.

This paper proposes a novel phase-locked loop (PLL) algorithm based on a fractional order proportional plus integral (FOPI) controller, tuned through Genetic Algorithm (GA), together with an all-pass filter to generate the quadrature signals to overcome the phase peak response of the widely applied double second order generalized integrator PLL (DSOGI-PLL). For comparison criteria, this paper uses the steady-state phase-angle error, speed of response to disturbances and harmonic and unbalance rejection to confirm the viability and superior performance of the proposal.

This manuscript proposes a way to tune fractional-order proportional–integral controllers, to synthesize them in hardware and to evaluate them by using hardware-in-the-loop technique. In order to validate the tuned controllers, it was imposed to control a plant where two loops of control were necessary. The obtained results showed satisfactory performance for both designed controllers and proved that fractional calculus can be implemented on high-performance digital processors. Controllers were implemented on the Altera DE2-115 cyclone IV EP4CE115 board.

This work presents comparative analysis, obtained through MATLAB/Simulink® platform, of a proposed Hybrid Fuzzy Logic controller and a classic Proportional-Integral (PI) controller, intended for mitigating the effects of partial shading in photovoltaic generation systems connected to a low voltage distribution grid. In this analysis, a seven-level cascaded Half- Bridge multi-level converter, modulated by phase shifted sinusoidal pulse width modulation, with a robust Droop Control strategy, was adopted as power stage. The system was subjected to several scenarios of solar irradiation changes, comparing its dynamic behavior using both control methodologies. In such scenarios, the proposed Hybrid Fuzzy Logic presented superior performance supporting its applicability.

The proposed paper presents the construction process of a high efficient and high-immune misalignment tolerant loosely coupled inductive power transfer (LCIPT) system using dynamic wireless power transfer (WPT) concept to charge a 48 V battery bank at 500 W through 16 cm air-gap. The purpose of this work is to investigate the influence of a third coil functioning as a transmitter coil. The resonant circuit as well as the electronic power converters used to implement a prototype are deeply explained.

In this work, inductive power transfer systems with five different compensation topologies are considered: series–series, parallel–series, series–parallel, parallel–parallel and double-sided LCC. State-space models are deduced in order to help engineers perform suitable dynamic analysis in the design process. Linearization procedures such as small signal assumptions are not employed. Finally, an example illustrates how the proposed equations can be used for analysis purposes.

In this paper some anti-islanding detection methods are evaluated through MatLab/Simulink® models. The methods are embedded into the control system of a voltage source inverter that is used to inject power to the grid from a set of photovoltaic modules. Due to low efficiency of the passive methods in detection of islanding and to the high cost of implementing the remote methods, only the active methods will be evaluated. In that sense, this paper presents comparative analysis regarding Active Frequency Drift (AFD), Slip-Mode Frequency Shift (SMS) and Sandia Frequency Shift (SFS) methods. Commonly, the active methods are implemented combining the passive sub/overvoltage and sub/overfrequency protection methods. The simulations presented comply with the voltage and frequency limits established by IEEE Std 929-2000 and harmonic distortion established by IEEE Std 519-2014.

Este artigo sugere o conversor multinivel em ponte H em cascata como uma solucao para reduzir os efeitos do sombreamento parcial em sistemas fotovoltaicos conectados a rede eletrica. Baseia-se na premissa de individualizar o rastreamento do maximo ponto de potencia de cada grupo gerador fotovoltaico, que define o numero de niveis de inversao. Para distribuir a potencia disponivel em cada conjunto fotovoltaico, foi utilizada a modulacao por deslocamento de fase. A sincronizacao a rede eletrica e o rastreamento de energia ocorrem atraves de um controle droop robusto integrado a alguns controladores proporcionais e integrais. O uso de controle droop robusto elimina a necessidade de algoritmos convencionais de sincronizacao, simplificaa modulacao e reduz o numero de controladores a serem ajustados. Os resultados da simulacao confirmaram a estabilidade e o bom desempenho do controle devido as variacoes de irradiância. As limitacoes do sistema proposto sao apresentadas, bem como a discussao de possiveis solucoes sao abordadas.

O principal objetivo deste artigo e apresentar uma solucao de software simples e confiavel, implementada em um microcontrolador de baixo custo, para extracao de maxima potencia e controle do fluxo de potencia em um sistema fotovoltaico conectado a rede eletrica. O sistema e composto por um microinversor monofasico de duplo estagio capaz de processar energia proveniente de um painel fotovoltaico de 250 W e injeta-la na rede eletrica de baixa tensao em 127 V e 60 Hz. Uma analise completa do sistema e apresentada, bem como detalhes da implementacao digital. Por fim, os resultados experimentais comprovam a acao da estrategia de controle utilizada, demonstrando o rastreamento do ponto de maxima potencia e o desacoplamento entre os dois estagios de conversao.

This paper proposes a strategy to mitigate the effects of partial shading in grid-connected photovoltaic systems. In order to reach this goal, a cascaded H-bridge multilevel (CHB-ML) converter was selected and the energy balance was obtained based on phase-shifted pulse width modulation, which allows individual power tracking of each level. Many constraints have been noted as the research has been evolving. That's why an extensive literature review was done aiming to find solutions to select better ways to compensate shading effects in more severe situations. It was noticed that there is a relation between the photovoltaic strings voltages and the capability of energy transmission, since the output voltage of each level must be summed to obtain the appropriate grid voltage level. Simulation results were obtained through Simulink/MatLab. The results were collected considering three different scenarios of solar irradiance and the limits of operation were addressed in order to evaluate the restrictions of the proposed solution.

This paper presents a topological change of the power stage and an adaptation of the control method of a three-phase water pump drive supplied by photovoltaic energy. Because it is a product-oriented project, the modifications have proven to be very advantageous since they indicate a considerable reduction in the final cost of the equipment. Such a reduction is mainly due to the use of lower voltage power switches and the removal of high frequency elevating transformers. In addition to the topological improvements, the adaptation of the control method allowed a significant improvement in the reliability and robustness of the system operation, functioning without interruptions due to partial shading and without overvoltage in the DC bus during startups with extreme conditions of irradiation.

The dynamic model of the series-parallel-series (SPS) compensated resonant inductive power transfer (IPT) system is derived. It has been shown that the aforementioned compensation is suitable for electric vehicles (EV) on-road charging due to its high-misalignment tolerance between coils. This work does not restrict its analysis to small signals, i.e., linear approximations of functions. Furthermore, the final expressions can be easily adapted to the series-series (SS) and parallel-series (PS) configurations, for these are particular cases of the SPS compensation. Experimental tests on a 500 W prototype validate the proposed equations.

In this paper, a new synchronous machine (SM) modeling is presented using the field reconstruction method (FRM). The FRM for SM has been developed and covers the two main categories: non-salient and salient poles. The FRM concepts are described, and the basis function for stator and rotor is detailed for the target machines. The FRM model is then used as a tool of machine analysis. Specifically, the overall air gap flux density distribution was determined for an arbitrary condition and further the Maxwell stress tensor was used to determine the forces/torque. Moreover, the concept of FRM was used to develop a flux reconstruction formulation, in which the stator tooth flux was used to estimate the flux linkage and then the voltages under no-load condition. All the results were compared to finite element solutions and show that the FRM provides a very accurate solution with the advantage of high computational efficiency. The main contribution of this new modeling is the quickly electromagnetic flux density estimation which creates an opportunity for real-time implementations with fast interactive algorithm processing for machine performance optimization, machine control, analysis, and diagnosis.

The problem of allocating the closed-loop poles of linear systems in specific regions of the complex plane defined by discrete time-domain requirements is addressed. The resulting non-convex set is inner-approximated by a convex region described with linear matrix inequalities. The proposed approach enables a trade-off between computational complexity in terms of mathematical program size and conservativeness. A case study is then carried out on a step-up power converter, comparing three different techniques. Experimental results are provided to show how the proposed control strategy can be employed to enhance its start-up and transient responses when subjected to input voltage and load variations.

This paper presents a control strategy for harmonic compensation using a fuzzy logic controlled shunt active power filter generating a 400 kHz PWM control signal compatible with recent Silicon Carbide inverters. The designed controller uses the p-q Theory, a modified Fuzzy DC regulator instead of a PI Fuzzy and high speed current generation for the 400 kHz PWM control signal. This paper also describes and analyzes the improvement in increasing the switching frequency and its relation to the total harmonic distortion at the source and the filter inductors size. Such control presents a complexity in terms of speed which is solved by the use of a FPGA. The FPGA allows the Fuzzy DC controller to operate in parallel with the p-q Theory and the 400 kHz PWM generator, optimizing speed and hardware with the use of VHDL-2008 fixed-point libraries. The controller is synthesized in the Altera Cyclone $$^{\circledR }$$ IV EP4CE115 from DE2-115 board. The implementation is experimentally validated by “FPGA in the Loop” and compared with other similar solutions showing better performance and effectiveness.

Demand management of Plug-in Hybrid Electrical Vehicles (PHEV) is an important requirement for the reduction of greenhouse gases and better use of the energy sources. Smart grids can control the power demand of PHEV, based on the knowledge of the demand curves. However, this information is not always known by PHEV owners or charging stations due to loss of data or due to the charging is done in cities with conventional power grids. These problems can increase the peak demand and makes dynamic pricing more difficult to implement. This paper proposes the use of fuzzy demands estimations to reduce the impact of these problems. This estimator is the basis of assistant software applications for PHEV users and charging stations to get more information for a best load management for PHEV. Results demonstrate the advantage of this proposal in the demand management for PHEV.

In this paper, the use of differential evolution (DE), a global search technique inspired by evolutionary theory, to find the parameters that are required to achieve optimum dynamic response of parallel operation of inverters with no interconnection among the controllers is proposed. Basically, in order to reach such a goal, the system is modeled in a certain way that the slopes of P- ω and Q -V curves are the parameters to be tuned. Such parameters, when properly tuned, result in system's eigenvalues located in positions that assure the system's stability and oscillation-free dynamic response with minimum settling time. This paper describes the modeling approach and provides an overview of the motivation for the optimization and a description of the DE technique. Simulation and experimental results are also presented, and they show the viability of the proposed method.

An important trend is the use of plug and play microinverters attached to the PV panel, allowing the so called AC module. However, these converters are subjected to high temperature and humidity. Thus, in order to improve reliability and achieve long lifetime, this work proposes a new topology that provides inductive power decoupling and eliminates electrolytic and even film capacitors, using a single ceramic or mica capacitor. The topology also provides inductor miniaturization and efficiency improvements.

In this work, a Shunt Active Power Filter (SAPF) using a multilevel inverter operating in low switching frequency is used to improve the power quality in electric metro power supply systems. The proposed topology is a three level/phase voltage source Neutral Point Clamped (NPC) and the Conservative Power Theory (CPT) is used to extract the harmonic currents. A current control schema sensing only the grid side voltages and currents is used and a capacitor voltage controller that balances the natural point voltage is implemented. Simulation results validate the ability of this set to mitigate harmonic currents.

Made available in DSpace on 2018-11-28T12:40:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Due to the absence of communication needs and great reliability, the droop-control technique is a great choice for controlling of inverters that are subjected to load sharing or to work in an islanded mode. On the other hand, current-controlled inverters are often used in grid-connected systems due to their fast response to power the implementation of maximum power point tracking (MPPT) algorithms to maximize the power extracted from these systems. However, the application of such algorithms in grid-connected droop-controlled systems is hampered by differences in the dynamic responses of the respective techniques. In this context, this study presents the development of a strategy that enables a push-pull converter controlled by MPPT and a low-power plug and play grid-connected inverter governed by droop control to operate stably even under variations in solar radiation. The goal is achieved based on the following two approaches: designing the dc-link capacitor properly and using a control loop in order to adapt the droop curves in accordance with the available input power. Theoretical analysis and experimental results have proven the viability of the approach. Univ Fed Mato Grosso do Sul, Elect Engn Dept, BR-79074460 Campo Grande, Brazil Univ Fed Itajuba, Elect Engn Dept, BR-37500903 Itajuba, Brazil Sao Paulo Fed Inst Educ Sci & Technol, BR-01109010 Presidente Epitacio, Brazil Ecole Technol Super, Elect Engn Dept, Montreal, PQ H3C 1K3, Canada Univ Estadual Paulista, Fac Engn Ilha Solteira, BR-15385000 Ilha Solteira, Brazil Univ Estadual Paulista, Fac Engn Ilha Solteira, BR-15385000 Ilha Solteira, Brazil

This paper presents a 10 years experience of data driven models for sensor validation applied for petroleum and natural gas industry. Auto-associative kernel regression has been used as the main modeling method. The models achieved were embedded in software called Sentinell, which is used for sensors diagnosis. The software is being used in a natural gas compression station, and it has been evaluated in other industries such as: refineries, offshore petroleum platforms, and thermoelectric power plants. In this work the theoretical background is presented, as well as the performance metrics indexes used to evaluate the models. The developed methodology and the results in the real plants are presented and discussed. The experience of these previous works might open future applications in high reliability automated processes.

In the original published article, Emilio Tanowe Maddalena’s last name was spelled incorrectly. It is correct as reflected here. The original article has also been updated.

DOI: 10.14684/intertech.13.2014.105-110 This paper proposes the modeling of a Parallel Active Filter (PAF) using a search algorithm to define the optimum parameters of inductance (Lf), voltage (Vdc) and bandwidth (Bw), since these parameters are mandatory to improve the performance of the modulation using hysteresis. The design of FAP devices may be obtained through the search algorithm of optimal points. The simulation prevailing contributes to the security of the system that should receive the compensation device as the design considers the current load. After finding the parameters through the optimization technique (based on an evolutionary algorithm named Differential Evolution), the active filter performance was evaluated and some simulation results proved the validity of the proposal. The association of DE with instantaneous power theory berfore utilized in active parallel filters, was capable mitigate the currentes harmonics so traht eliminate the unbalance between phases, presenting satisfactory results. Index Terms - Differential evolution, parallel active filter, parameters optimization, instantaneous power theory.

DOI: 10.14684/intertech.13.2014.432-436 This paper presents a proposal for measurement, analysis and control of a three-phase power grid in four quadrants to identify the power flow using the described equations in VHDL, which are synthesized and implemented in FPGA. The results were validated using FPGA simulation techniques such as FPGA in-the-loop, co-simulation, embedded processing and the comparison with the experimental practical tests. Through the controller available resources it can minimize voltages and currents reading errors and delays, performing faster analysis and control response acting on the system with almost instantaneous decisions making. Index Terms - FPGA, VHDL, four quadrants, power flow, measurement.

DOI: 10.14684/intertech.13.2014.167-171 This work presents the development of a dsp-based device that performs electric signals processing from triphasic system in order to measure active, reactive and apparent power from a bus. Therefore, three algorithms will be embedded associated with pq Theory, Conservative Power Theory and Definitions IEEE Standard 1459-2010. The Hardware system consist of a signal conditioning board, that use voltage and current sensors; and a control board that contains a TMS320C6713 float point DSP, an interface control with keys and display, and ETHERNET module. After signal acquisition of voltages and currents the ADC0808 convert them to digital bits and outputted serially to DSP that apply the power algorithms. Some results are presented what is possible evaluate the model proposed from comparison among simulation and algorithm results since both are corresponding results being according to expected. Finally conclude that with advance of this work more results can be obtained. Index Terms - DSP, Smart Meter, Smart Grid, Power Theory.

DOI: 10.14684/intertech.13.2014.223-227 This paper proposes an analyse of fuel consumption in Diesel generator - GD with actuation primary machine of kind Internal Combustion Engine – ICE cycle Diesel. So, are essayed two types of distincts loads and both of 2 kW. The first is a Linear Load thats response signal is proportional to exciting signal; the second Load is Non-Linear Load thats response presents a distortion related to excitement entrance signal. The Linear Load was equipped with a non-controlled triphasic rectifier with inductive and capacitive filter in the output, also knows that LC filter. In the final is possible assess if the fuel consumption of GD changes to these loads. Therefore, during the essays the levels of voltage and aceleration of GD was sastifieds allowing compare the loads. A proportional control was implemented in the system acceleration of MCI, which enabled GD maintain voltage between 127 V to 130 V. Index Terms – gerador diesel; carga linear; carga nao linear; retificador trifasico; gerador sincrono

The objective of this paper is to present a support system to manage electricity consumption contracts for Smart Grid environment. The system modeling uses historical data consumption and energy trading rules to find the optimal contract structure. Focused Time Lagged Feed forward Network was used to model the historical data. The global search tool Differential Evolution was used to find the best contract structure. This paper presents the use of the tool with current Brazilian pricing rules. However, to change the rules for a dynamic scenario of Smart Grid can be easily implemented. The results are satisfactory and indicate the feasibility of the system for different cases.

Small synchronous generators may present an output voltage with a relatively high harmonic distortion. It comes from the fact that the flux density distribution along the air gap is not a pure sinusoidal waveform. In this paper the Field Reconstruction Method (FRM) is used as a tool for search the optimal field current excitation in order to achieve a flux distribution closer to sinusoidal. FRM is used as surrogate the Finite Element Technique due its high computational efficiency. A commercial machine is modeled and then a routine is developed to modify the current profile of field excitation in attempt to reduce the Total Harmonic Distortion (THD) in the output voltage waveform. The simulation results showed a voltage profile improvement.

This work presents a control methodology in order to enable connecting photovoltaic generators to the grid in such a way that the modules are always going to operate in their maximum power point (MPP). The work uses the droop control technique together with a MPPT method. The integration of these methods presents two crucial points. The first one is how the P-ω curve is modified according to the photovoltaic panel output power and the DC-DC converter output voltage. The second point is the establishment of a DC-link connecting the DC-DC converter to the inverter. Its goal is cancelling the impact caused by the different dynamic response of the methods. This work presents several advantages for environment and reliable and safe power system growing. The experimental results verify great tracking, stability and reliability, even during irradiation transients.

This paper describes the design and implementation of a 480W three-phase converter for photovoltaic water pumping systems. The converter is designed to present a high-efficiency and high lifetime market friendly product. With a single digital signal controller control and common ground gate-driving, the converter is a suitable solution for remote regions where a ½hp water pump is applicable. The control strategy integrates P&O MPPT and Space Vector Modulation. Simulation and experimental results are presented and show converter's efficiency up to 91.3%.

This paper proposes the design of a Tri-State Boost Current Source Inverter with a Modified Space Vector Pulse Width Modulation. This converter is promising for many renewable energy applications. The Modified Space Vector PWM was created in order to determinate the converter state times and generate the switching signals, depending on the photovoltaic panel MPPT algorithm output and the modulation index. The Tri-State Boost CSI eliminates the RHP zero that is present in the Traditional Current Source Inverter by adding a freewheeling state. The partial experimental results show that this converter can operate as expected and is suitable for stand-alone situations that require high efficiency and reliability. The target application of the converter is to track the point which occur the maximum power transfer from the panel to the load.