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We propose an asynchronous single flux quantum (SFQ) logic gate composed of a conventional clocked logic gate and an input signal merger that generates a self-clock for the clocked logic gate. By using this self-clocking, we can design any 0-preserving logic gate, including exclusive OR (XOR). The proposed asynchronous SFQ logic gates have adjustable allowable input skew by varying the delay between the merger and internal clock input for the clocked logic gate. We design and evaluate the asynchronous AND, OR, and XOR gates that have an allowable input skew of approximately 8 ps assuming the use of the 10 kA/cm 2 Nb fabrication process using the proposed design method. We experimentally confirm the correct operation of the asynchronous SFQ XOR gate. We design a completely asynchronous 4-bit-input carry-lookahead adder (CLA) using the designed asynchronous gates. We found that the circuit area and number of Josephson junctions required to design a 4-bit-input CLA can be reduced by > 50% compared to that of the synchronous concurrent-flow 4-bit-input CLA without deterioration of the throughput.

A SQUID tandem is a two-stage amplifier consisting of the front end SQUID at T << 1 K and the booster SQUID at T ∼ 4 K. We give an overview of the dc SQUID design for the tandem used in the recent 37-pixel frequency domain multiplexed (FDM) readout demonstration of X-ray calorimeters. The SQUID devices were fabricated with pillar-type Josephson junctions at the nominal JC = 500 A/cm2 critical current density. We further discuss possible improvements to the FDM tandem configuration, including (i) the class-B operation for better power efficiency, (ii) the input power combiner as an improvement over the simple T-junction summing, with the promise for larger multiplexing factors, and (iii) the new booster SQUID device. The new improved booster is a 8-parallel 66-series SQUID array fabricated with SWAPS Josephson junctions at the nominal JC = 1.5 kA/cm2 critical current density, and it shows dV/dΦ > 30 mV/Φ0 gain in the symmetric-slope operation, as well as ΦN ≈ 0.05 μΦ0 / Hz1/2 flux noise.

In this paper, a Phase-shift-modulated (PS) Resonant Two-switch Boosting Switched-capacitor Converter (RTBSC) and its modulation map are proposed. Compared with the traditional RTBSC, all diodes are replaced by active switches and then phase-shift modulation is applied. The advantages of the modified topology are obtained as follow. 1) The voltage gain can be regulated efficiently either below or above the nominal value even at light-load condition, making it suitable for applications with voltage fluctuations; 2) The conduction loss is reduced by replacing all diodes in RTBSC with low turn-on resistance transistors, especially for high-order and high-gain configuration; 3) All switches achieve the zero-voltage-switching (ZVS) turn-on operation; 4) The soft-charging property smooths the current profile. Aside from the topology modification, a comprehensive analysis of operation principle, voltage gain, component stress and ZVS region is given. On the basis, a modulation map with the optimal operation region is proposed. It provides a guideline to operate and design such converters in the target gain range, low component stress and ZVS region, making up for the lack of modulation map and design guideline in aforementioned literatures. A 120W prototype with low-voltage side 43-60V and high-voltage side 150V was designed to verify the above analyses.

Conventional Al-air battery has many disadvantages for miniwatt applications, such as the complex water management, bulky electrolyte storage and potential leakage hazard. Moreover, the self-corrosion of Al anode continues even when the electrolyte flow is stopped, leading to great Al waste. To tackle these issues, an innovative cotton-based aluminum-air battery is developed in this study. Instead of flowing alkaline solution, cotton substrate pre-deposited with solid alkaline is used, together with a small water reservoir to continuously wet the cotton and dissolve the alkaline in-situ. In this manner, the battery can be mechanically recharged by replacing the cotton substrate and refilling the water reservoir, while the thick aluminum anode can be reused for tens of times until complete consumption. The cotton substrate shows excellent ability for the storage and transportation of alkaline electrolyte, leading to a high peak power density of 73 mW cm−2 and a high specific energy of 930 mW h g−1. Moreover, the battery discharge capacity is found to be linear to the loading of pre-deposited alkaline, so that it can be precisely controlled according to the mission profile to avoid Al waste. Finally, a two-cell battery pack with common water reservoir is developed, which can provide a voltage of 2.7 V and a power output of 223.8 mW. With further scaling-up and stacking, this cotton-based Al-air battery system with low cost and high energy density is very promising for recharging miniwatt electronics in the outdoor environment.

This brief proposes a low voltage ultra-low power 10-bit 100-MS/s successive approximation register (SAR) analog-to-digital converter (ADC). To overcome the performance degradation due to the signal-related current fluctuation under lower supply voltage, an adaptive-biasing comparator with current self-compensation (CSC) technique is proposed to obtain a constant working current, reducing the minimum supply voltage from 0.7V in conventional ADCs to 0.55V. Since full-scale range shrinks with the supply voltage, voltage undershoot in power rail caused by capacitor digital-to-analog converter (C-DAC) deteriorates effective-number-of-bits (ENOB). Conventional solutions involve enhanced regulators and large decoupling capacitors, which cost remarkable power dissipation and large chip area. This brief presents a pulse-injection undershoot compensation technique which reduces the DAC-related supply fluctuation from a typical 15mV to 1.8mV, and improves the ENOB by 0.4 bit. The prototype was fabricated in TSMC 28nm HPC CMOS technology. The proposed SAR ADC achieves an SNDR of 54.7dB and an SFDR of 68dB with the power consumption of 0.16mW under 0.55V supply voltage, a figure of merit (FoM) of 3.6-fJ/conversion-step is achieved. The chip area of the ADC core is 130μm×225μm.

Electrical energy generated also comes from several energy, namely water, steam, nuclear, etc. In Indonesia the type of steam power plant is a type of power plant that is widely used, where one of the crucial problems that are often encountered in this generation system, namely the problem of stability. The stability of the electric power system is the ability of the system to return to normal or steady operation after a large load load switching or interference. Disruption or load switching that exist in the system must be muted and aligned in a certain time to be said to be stable. Causes of instability are disruptions in the form of large capacity load switching, and the type of interference. One aspect that affects the stability itself is the transient stability. The transient stability is related to the sudden influx of large-capacity loads and affect the performance of the generator, therefore it is necessary to analyze the voltage and frequency transient stability for the evaluation of the capability of the electrical system so that the system maintains the continuity of the supply of electrical energy to the load normally. Based on the research results, the current flowing before the disturbance of 98.9 A and current disturbance of 145.2 kA. This causes the voltage response to decrease 50% of the nominal, and the frequency increases to 50.36 Hz. The time required from the disturbance condition to a stable condition within 5 seconds. Thus, the voltage response does not meet the standards and the frequency is still within the standard according to the 2007 EMR Energy Regime during an emergency. So to keep the transient stability of voltage and frequency can be adjusted voltage with AVR, setting speed droop governoring and release and connection of load.

This paper studies the coordinated use of smart inverters with legacy voltage regulating devices to help increase the energy savings from conservation voltage reduction (CVR) in distribution systems with high photovoltaic penetration. Two voltage optimization algorithms are developed to evaluate the CVR benefit by considering two types of smart inverter functions: aggregated reactive power control and autonomous volt/VAR control. In each algorithm, smart inverters are coordinately controlled with the operation of legacy voltage regulating devices including load tap changers and capacitor banks. Both algorithms are tested on representative utility distribution system models. Simulation results demonstrate that the proposed algorithms can achieve around 1.8-3.6% energy savings when only using legacy voltage regulating devices and an additional 0.3-0.9% when adding smart inverters.

The steep voltage slopes of today’s wide-bandgap (WBG), fast-switching power semiconductors — like SiC and GaN — lead amongst other challenges to reflection on long cables and thereby overvoltage at inductive loads. To enable the use of these inverters with motors without specially reinforced insulation the voltage slopes need to be slowed down. This article presents a new low-loss countermeasure, which involves the parallel connection of two half-bridges via an interphase transformer. For this one half-bridge is delayed relative to the other one by a delay tuned to a resonant circuit. Undesired DC components in the cross-current of the interphase transformer occur due to non-idealities in the voltage symmetry. The subsequent DC magnetization ultimately can cause the core to saturate. The paper describes the effects due to inaccurate timings and the aspects to keep in mind when dimensioning the magnetic core. Also, this article describes an approach to deal with the undesired current components using a closed-loop control. For that, a special differential-mode shunt is used which enables a dedicated measurement of the cross-current mean value and mitigates the influence of the switching frequency. Finally, the controller concept is presented. The controller is implemented and verified on a 500 kVA SiC inverter test bench.

In this paper, the issues related to short-circuit calculations in hybrid AC/DC microgrids are discussed. The reference standard for short-current calculations in DC systems is the IEC 61660, which provides a mathematical formulation of the problem. The standard only includes radial DC grids and does not consider a more complex system, such as meshed DC systems or a hybrid AC/DC microgrid. This paper proposes a generalized approach that can be used independently of the characteristics of the hybrid system. The proposed approach is applied to four test microgrids with different distributed sources and number of nodes and the results are compared with those obtained simulating the same grids with Neplan 360®.

Artificial intelligence is used for various applications and is promising as an indispensable infrastructure in future societies. Neural networks are representative technologies that imitate human brains and exhibit various advantages. However, the size is bulky, the power is huge, and some advantages are not demonstrated because they are executed on Neumann-type computers. Neuromorphic systems are biomimetic systems from the hardware level to implement neuron and synapse elements, and the size is compact, the power is low, and the operation is robust. However, because the conventional ones are not composed of fully optimized hardware, the power is not yet minimal, and extra control circuits must be used. In this article, we developed a neuromorphic system using memcapacitors and autonomous local learning. By using memcapacitors, the power can be minimal, and by using autonomous local learning, the control circuits to handle the synapse elements can be deleted. First, the memcapacitors are completed in a cross-bar array, where the ferroelectric layers are sandwiched between the horizontal and perpendicular electrodes. The polarization and capacitance exhibit hysteresis due to the dielectric polarization. Next, autonomous local learning is introduced as follows. During the training phase, associative patterns to be memorized are directly sent, relatively high voltages are applied, and dielectric polarizations are induced. During the operation phase, relatively low voltages are applied, and input signals are weighted with the capacitances of the memcapacitors, summed, and transferred as the output signals. Finally, the experimental system is set up, and the experimental results are acquired. The memorized patterns during the training phase, distorted patterns as the input signals during the operation phase, and retrieved patterns as the output signals in the operation phase are shown. Researchers found that the retrieved patterns are completely the same as the memorized patterns. This means that the neuromorphic system works as an associative memory.

This study aimed to analyze the gap between the concepts of current and voltage between junior high school students and teachers in Indonesia. The number of samples was 720 students, class X, and 527 teachers who were selected by purposive sampling diagnostic test current, mains voltage, 30 question items valid and reliable. The results show that even with a simple circuit (one or two lamps and a battery), there are still gaps in the conception of current and voltage; if the circuit is more complicated, There will be many gaps in conception, namely: (1) consumption model, (2) local reasoning, (3) voltage source is seen as a constant current source rather than a fixed voltage source, (4) voltage difference, (5) series and parallel terms, (6) source electrons, (7) power consumption, (8) guess the answer choices, (9) the explanation does not match the correct choice.

A two-To-Three (2/3)-level dual-Active-bridge (DAB) converter is a promising dc-dc converter for medium-and high-voltage applications. That is due to its advantages like high power density, galvanic isolation, and capability of withstanding higher voltage ratings compared to the two-level DAB converters. However, the open-circuit fault (OCF) is critical for the 2/3-level DAB converters, resulting in various negative effects, e.g., dc bias, overshoot current, and capacitor voltage imbalance. To address these issues, it is necessary to develop fault diagnosis and fault-Tolerant control strategies. This article, thus, proposes a method to identify the faulty switch based on the dynamic characteristics when the OCF occurs. The midpoint voltages of the neutral-point-clamped bridge arms are employed as the fault diagnosis signals, where the faulty switch can be identified accurately based on the mean values and duty cycles of the midpoint voltages. Subsequently, a fault-Tolerant control scheme based on a complementary-switch-blocking method is proposed. In this scheme, when the OCF occurs on one switch, the gate-driving signal of its complementary switch is blocked, and the OCF negative effects, e.g., dc bias, overshoot current, and unbalanced capacitor voltages, can be alleviated significantly. Furthermore, the power transfer capability of the 2/3-level DAB converters is enhanced with the proposed scheme compared to the traditional bypass-Arm method. Finally, experimental tests are carried out to verify the theoretical analysis.

Current quantum systems based on spin qubits are controlled by classical electronics located outside the cryostat at room temperature. This approach creates a major wiring bottleneck, which is one of the main roadblocks toward truly scalable quantum computers. Thus, we propose a scalable memristor-based programmable DC source that could be used to perform biasing of quantum dots inside of the cryostat (i.e. in-situ). This novel cryogenic approach would enable to control the applied voltage on the electrostatic gates by programming the resistance of the memristors, thus storing in the latter the appropriate conditions to form the quantum dots. In this study, we first demonstrate multilevel resistance programming of a TiO2-based memristors at 4.2 K, an essential feature to achieve voltage tunability of the memristor-based DC source. We then report hardwarebased simulations of the electrical performance of the proposed DC source. A cryogenic TiO2-based memristor model fitted on our experimental data at 4.2 K was used to show a 1 V voltage range and 100 uV in-situ memristor-based DC source. Finally, we simulate the biasing of double quantum dots enabling sub-2 minutes in-situ charge stability diagrams. This demonstration is a first step towards more advanced cryogenic applications for resistive memories such as cryogenic control electronics for quantum computers.

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works This paper proposes a comprehensive analysis of the Modular Multilevel Converter (MMC) focusing on the different arm applied voltage components, that this paper will refer as degrees of freedom (DOFs), which must be considered in order to perform the internal energy balancing of the converter. The analysis relies on the commonly used differential and additive reference frames. By means of a steady-state analysis, the different voltages components applied and currents components flowing through the converter are studied and an in-depth discussion of the roles of each DOF in the converter is presented. Furthermore, the mathematical expressions of the power exchanged between the AC/DC networks and within the converter, between the arms (vertical) and among phase-legs (horizontal), are derived considering all the DOFs of the MMC, revealing potential interactions among the differential and additive quantities. Finally, the theoretical analysis is validated through comparisons between the values obtained with the mathematical expressions and the simulation results assuming different case scenarios.

Production potential of cow dung for the generation of electricity was investigated using microbial fuel cell (MFC). Cow dung was collected from FUTA farm and Ilesha Garage farm in Akure. Voltage and current was measured per day for 21 days and the electrode used for the set up are carbon-carbon and carbon-aluminium electrode. Proximate, physico-chemical and mineral composition were determined using standard methods. Isolation and identification of microorganisms present in the cow dung were determined before and after generation of voltage and current using microbiological techniques. The microorganisms isolated wereProvidencia alcalifaciens, P. rettgeri, P. stuartti, Escherichia coli, E. fergusonii, Morganella morganii, Staphylococcus haemolyticus,S. aureus,Micrococcus luteus,Fusarium solani, Saccharomyces cerevisiaeandMucor mucedo. The highest voltage 0.737±0 mV and electric current 1.265±0 mA were generated from FUTA cow dung. The pH ranged between 7.3 to 9.9 and the temperature ranged between 25 ˚C to 33 ˚C during generation of voltage and current. This study has shown that cow dung is a potential substrate for generation of electric current using fabricated double chamber MFC.

As a novel micro-propulsion system for small satellites (from micro to nano), the ionic liquid electrospray propulsion system is a promising candidate. However, performance measurement and evaluation of the Ionic Liquid Electrospray Thruster (ILET) is one of the most challenging issues for practical application, due to the difficulties in the development of a prototype and direct measurements of micro-thrust and small flow rate. To address this issue, a Modular Ionic Liquid Electrospray Thruster (MILET) prototype is constructed, and a diagnostic system for thrust and mass flow rate is specially developed based on an analytical balance method. With the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate as the propellant, a series of experiments is carried out on the MILET prototype under a wide operating condition through changing the applied voltage to control the thrust. Under different applied voltages, the thrust and the mass flow rate of the propellant are directly measured. The propulsive performance parameters of the thruster, such as thrust, specific impulse, thrust-to-power ratio, thruster efficiency, etc., are comprehensively analyzed. Then, a performance comparison is made between the MILET and other representative ILETs. With a relatively low applied voltage ranging from 1550 V to 2000 V, the MILET achieves a quasi-constant specific impulse of 1263 s with the averaged thrust-to-power ratio of 65.2 μN/W and thruster efficiency of 40.7%. The performance of ILET is also compared with other typical electric propulsions. The results demonstrate that the ILET exhibits an excellent ability of minimalization with high specific impulse and thruster efficiency, which guarantees a great superiority in micro propulsions. Finally, the ways to further improve the performance of ILET are discussed, which further confirms the potential prospect of ILET. The present result helps to advance the development and application of ILET.

Thomson coil actuators consist of an electric coil repelling a metallic disk. They are considered the fastest electromagnetic actuators for short travels and for this reason are favored for DC circuit breakers. Although the basic physics are understood, the actuator’s few components are very interdependent, making for a difficult analysis. Actuator design so far has thus been limited to trial and error based on finite-element models. In this paper, a novel approach is presented based on the electromagnetic frequency response of the actuator. This method is shown to be an intriguing analysis tool and various actuator design directions are presented. Experimental results provide a confirmation of the analysis.

This article proposes a capacitor condition monitoring (CM) method for modular multilevel converter (MMC) in motor drive applications. The proposed method is based on wavelet decomposition of transient voltage signals, which is independent of modulation schemes and control strategies. The equivalent series resistance (ESR) change can be detected with a moderate computation requirement. Both simulation and experimental results have verified the performance of the proposed method.

Conventionally, single phase shift control technique is used, for dual active bridge (DAB) which works efficiently at unity voltage conversion ratio and full load. However, when there is mismatch between primary voltage and reflected secondary voltage on primary side at light load, its efficiency reduces because of increased current stress and circulating power. Moreover, due to single control variable, its power flow controllability is confined. In this paper, isolated bi-directional T-type multilevel dual active bridge dc-dc converter topology is presented. It has five level voltages on both the primary and secondary side of high frequency transformer, which reduces the current stress and circulating power over wide operating range. It also has five control variables which gives extra edge for enhancing power flow controllability. Comparative analysis reveals that the proposed converter has high efficiency over wide operating range, due to reduced circulating power and current stress. Performance of the proposed T- type multilevel dual active bridge DC-DC converter topology has been verified via simulation in MATLAB.

In pressure sensors, four piezoresistors connected in a Wheatstone bridge are often provided with a voltage varying between 5 and 10 V. Unfortunately, this voltage is a source of drifts created by electric heating. This study focuses on the internal heating and piezoresistive effect of piezoresistors represented by the variation of their resistivity. To do this, we use the finite difference method (FDM) to solve the heat transfer equation, taking into account the conduction in Cartesian coordinates for the variable regime. We examine how the temperature affects the piezoresistivity in these sensors when the potential is applied. In this case, the variation of the temperature has been calculated as a function of applied voltage, as well as for the operating time of the sensor. Furthermore, the evolution of resistivity over time was determined for several geometric properties of the membrane using the mobility model. This was established for different doping levels. Additionally, the change in resistivity due to the application of voltage was evaluated. It was observed that resistivity is greatly affected by the temperature rise produced by the applied voltage when the device is actuated for a prolonged time. Consequently, this results in drifting in the output response of the sensor.

The use of equipment with a high non-linear load causes a decrease in the quality of power (Power Quality) at Malang City Point Apartment. Power quality analysis is an important requirement in the electrical system and needs special attention to save energy and costs. Savings can be achieved by reducing or even eliminating losses resulting from the use of non-linear loads. This thesis aims to present the results of an analysis of power quality conditions at Malang City Point Apartments. This analysis includes voltage, current, voltage and current imbalance, power factor, current THD and measured voltage. The system is designed using Web - Based Power Quality Meter (PM 5110) as a measurement tool, then the results are analyzed and compared with existing standards to evaluate power quality in Malang City Point Apartments. Among the various power quality problems measured, it was found that the main problems of power quality in Malang City Point Apartments were the occurrence of overvoltages and current harmonic distortion. So it is necessary to do repairs on this to overcome the overvoltage by reducing the operation of equipment that has a large load and repairing neutral conductors. Furthermore, to reduce the system harmonics, it is designed by designing a single tuned passive filter and simulated using the ETAP software version 16.0.0.

The present day ever escalating power demand moves the operating point ofthe distribution networks in the vicinity of the voltage stability boundaries.Any small reactive power unbalance between the generation and demandmay trigger voltage instability, which makes the voltage magnitude to fallslowly until a rapid change occurs. This paper presents an adaptive dragonflyoptimization based method for placement of shunt capacitor banks witha view of improving the voltage stability besides enhancing the voltageprofile and lowering the network losses. Simulation results on 33 and 69-node distribution networks exhibit the greater performances of the suggestedalgorithm.

In the hardware design of battery energy storage system (BESS) interface, in order to meet the high-voltage requirement of grid side, integrating 10-kV silicon-carbide (SiC) MOSFET into the interface could simplify the topology by reducing the component count. However, the conventional gate driver design is challenging and inextensible in BESS, since the high-voltage rating and high dv/dt bring the requirements of high-voltage isolation and low common-mode capacitance. Therefore, in this article, a scalable converter-based self-powered (SCS) gate driver is further proposed. A 5-kV input power extracting converter based on a voltage-balanced SiC MOSFET stack is constructed to self-power the gate driver, which exhibits simplification of basic topology and sufficient gate driver power handling capability regardless of the switching requirement of main loop power device. Besides this, the power extracting converter is designed to act as a clamping resistor-capacitor-diode (RCD) snubber circuit, which makes the SCS gate driver scalable to the series connection of power devices. Analysis and design consideration are given in detail, followed by the experimental verification using 10-kV/10-A SiC MOSFETs.

Wide voltage design has been widely used to achieve power reduction and energy efficiency improvement. The consequent increasing number of PVT corners poses severe challenges to timing analysis in terms of accuracy and efficiency, especially for low voltage corners. In this paper, a learning-based timing prediction framework is proposed to predict multi-corner path delays across wide voltage range by exploiting both the correlations of circuit topology information and timing analysis results from known corners, which are respectively captured by LSTM (Long Short-Term Memory) and MMoE (Multi-gate Mixture-of-Experts) networks. Experimental results demonstrate that with the proposed framework, the path delays at low voltages could be predicted across wide voltage range with rRMSE of less than 2.9% and 4.7% for seen and unseen circuits respectively. Compared with the learning-based models used in prior works, the proposed framework achieves significant prediction error reduction by up to 19.1×.

A new dc-dc converter with high voltage gain is proposed in this study. The proposed converter consists of two switches which are turned on and off simultaneously. Additionally, two Switched-Capacitor (SC) cells and one Energy Storage (ES) cell are utilized in the structure of the proposed converter. These result in high voltage gains at low values of the duty cycle. Besides, the voltage stress across the power devices is low and below half of the output voltage. Therefore, the MOSFET switches with low RDS-on and devices with reduced nominal voltage can be used in the proposed converter which in turn reduces the conduction and turn-on losses. The analysis of the voltage and current stresses of the devices is accomplished. The circuit performance is compared with other solutions in the literature in terms of voltage gain and normalized voltage stress of switches and diodes. Eventually, in order to verify the theoretical analysis, the experimental results are provided.

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works This paper proposes an optimization-based size reduction methodology for Modular Multilevel Converters (MMC), focusing on minimizing the converter's sub-module capacitor CSM. The analysis is performed considering both the converter's current and voltage limitations and the Transmission System Operator (TSO) Fault Ride Through (FRT) requirements. By means of a steady-state analysis, the time-domain expressions of the converter's arms energies are obtained and their behavior throughout the MMC's operating range is shown. Based on these expressions, the optimization-based problem to reduce the CSM size is developed and its constraints are imposed to ensure that the converter's voltage and current levels are within its design limitations. The suggested method is compared with different approaches for distinct active and reactive power set-points, where it is shown that the SM capacitor size can be reduced up to 24% in comparison with the method with worst performance and up to 7% regarding the best method used for comparison purposes. Furthermore, time-domain simulations of the MMC considering several AC voltage sags are performed in order to demonstrate that the dynamics of the SM capacitor and the arm applied voltages are within acceptable margins during the different operations.

This paper introduces a new modular cascaded multilevel inverter (MLI) which is composed of a cascaded connection of submodules (SMs). The combination of basic cells (BCs) with polarity changer H-Bridge produces the SMs, which is the basis of the introduced inverter. Owing to its high modularity, the proposed inverter can be extended to reach higher voltage levels. Hence, two extensions are suggested: 1) Extension based on cascading more BCs within each SM, and 2) Extension based on cascading more SMs. Using a set of algorithms, the magnitude of DC voltage sources is determined to synthesize the proper AC side voltage waveform. Furthermore, the proposed topology is optimized in different ways to achieve the desired purposes, such as maximizing the number of voltage levels, minimizing the number of switches and DC sources, and providing the least total standing voltage on the switches. Therefore, in each of the mentioned optimization goals, the optimal structure is obtained. A prototype of the presented MLI is defined and its performance is verified through several simulation studies in MATLAB/Simulink and experimental tests. Besides, a comprehensive comparison is made with the best performance of the existing alternatives to demonstrate the merits and superiorities of the proposed MLI.

This paper shows how to exploit the degree of freedom represented by the common-mode voltage, which is inherent in three-phase Cascaded H-Bridge (CHB) converters, to minimize the total Root Mean Square (RMS) current value of the distributed dc sources. An optimal common-mode voltage injection law is derived, constituting a Maximum Power Per Ampere (MPPA) modulation strategy with respect to the currents of the dc sources. The potential benefits introduced by the proposed algorithm are analyzed in the context of battery-fed CHB converters and validated experimentally with a three-time-constant Randles model of a battery cell. The MPPA strategy is compared with traditional common-mode voltage injection methods, and battery loss reduction is demonstrated. The obtained battery energy saving is dependent on the converter modulation index and power factor. Experimental tests on a 36-cell full-bridge CHB converter validates the simulation and numerical derivation. To demonstrate the efficacy of the proposed method in practical applications, a 3 MW Energy Storage System (ESS) and a 110 kW Battery Electric Vehicle (BEV) undergoing standard drive cycles are presented as case studies. Compared to traditional modulation strategies, the MPPA strategy reduces the battery losses by up to 10.9% in the ESS and 27.5% in the BEV application.

Publisher Copyright: Author In this paper, a single source five-level boost inverter has been proposed and analyzed. The proposed structure includes a five-level inverter and a single-input multi-output (SIMO) boost converter. In this structure, the DC link voltage has been controlled by controlling the implemented DC-DC boost converter. In addition, the inverter switching pattern has been obtained based on the pick current control (PCC) method. In order to test and prove the performance of the proposed structure, this system is tested with the local grid. Since the active and reactive powers have been controlled based on the PCC method, the generated energy in a renewable energy source can be transferred to the local grid with a controlled and high-quality current. In this paper, the proposed structure has been introduced and its operation in different modes has been analyzed completely. Furthermore, the design considerations of the required elements have been investigated. Also, the power loss analysis and the comparison results of the proposed converter with other similar structures have been presented. Finally, in order to test the practical performance of the proposed structure and prove the theoretical analysis, a 620 W laboratory prototype of this structure has been assembled and its performance with the local grid has been tested.

Electric discharge machining (EDM) routehas capability of machining hard materials. Even intricate shapes can be machined by this process. Traditional machining routes develop machining issues like tool wear and pitiable surface finish. It can be overcome by the EDM process. The objective of this work is to prepare AA6351-10wt%Al2O3-5wt%Gr composites through stir casting process. The manufactured composites were machined via EDM route and their machining characteristics material removal rate (MRR) and surface roughness (SR) were studied via Taguchi process. The results display that for MRR current is the major influencing parameter and for SR voltage is the foremostpersuading parameter.

Solar energy, wind energy etc. are the main sustainable energy sources used around the world. These sustainable energy sources are used in day-to-day life in various forms for numerous purposes. One of the highly used sustainable energy sources is the solar energy which with the help of photovoltaic (PV) cells can be made use for the generation of electrical power. However, these sources generate less voltage values and thus it requires a high gain converter. In this paper, a modified Luo with flyback DC to DC converter is presented that assures high voltage gain, single switch, less stress across the components and less ripple current. Furthermore, the simulations along with the hardware prototype for the presented converter is carried out and presented in this paper.

A new, effective pi-based control method for a neutral 3-level inverter with a unified series and shunt converter is provided in this work. The proposed series of shunting and 3-levels can restrict harmonic current source and combat interruptions of voltage such as voltage drops, swells, imbalances and harmonics. With serial integration and shared DC bus capacitors, it is constructed with Active filters (AFs). With the proportional integrated voltage controller, the DC voltage is continually maintained. The Synchronous SRF theory is utilized to gather APF reference signals and power response theory (p-q theory). For the switching signal the shunt and series APF signal generated by the control algorithm and the observed signal was supplied into two controllers. In the management of the APF Series, PI approaches are employed to enhance capacities and shift 3-tier conversion devices. The power, power and voltage harmonics and any correction for any other voltage disturbance are assessed in the proposed 3 level range and shunt converter with the Matlab-Simulink Software and SimPower System Tool Box. The results of the simulation show the performance of the three-story series & shunt converter's non-linear load for improving energy quality at the sharing point.

The tool and die applications are preferred the unconventional machining processes as they are popular in machining the difficult to cut type complex contour/ profile. The complex profile machined on hard material. Some special materials like Stainless Steel 12X18H10T withstand its inherent properties even it exposes at higher temperature. This investigation aims to expand its application by investigating its machinability in Electro Chemical machining process for surface finish. The process parameters like gap between work material and tool, discharge current, concentration of electrolyte and applied voltage at three levels. The Taguchi approach is used for optimizing the process parameters and confirmation runs also conducted for developing the mathematical modelling. For optimizing number of experiment the Taguchi L9 is utilized for this investigation.

Battery power has been a popular choice of delivering DC power to many portable RF systems including wireless sensor nodes/internet of Everything (IoE). An autonomously powered RF system of the orders of 100’s of µwatts is becoming increasingly popular in recent times because of integrated solutions in energy harvesting. The minimum sensitivity of an RF energy harvester and the targeted deliverable output voltage for a specific load resistance are dictated by threshold voltage of transistors used and reverse leakage of such transistors. A detailed look into the architectures of rectifiers can help tackle design problems in the RF-DC conversion process. So in this work we focused on the design of integrated RF energy harvesting by studying four important architectures of RF-DC converters. To achieve a fair comparison between these architectures, a matching network operating at 0.8 MHz is designed and applied for simulation. All of these converters are tested in LT-SPICE XVII using the same designed matching network and the rectifiers are implemented in 180 nm CMOS technology.

Pulsed electric field disinfection is an effective non-thermal water disinfection technology. Compared to conventional disinfection techniques, PEF inactivation has several advantages including no by-products. In this context, the use of silver ions in conjunction with a reverse osmosis filtration system has been proposed as a safe and cost-effective treatment approach that can be used in a point of use technologies. This system contains two silver meshes as electrodes inside a reverse osmosis membrane with the application of a pulsed electric field on it as a disinfection method, After conducting chemical and physical tests of the water samples before and after the treatment system, it was noticed that most of these characteristics were significantly affected by increasing the number of electrical impulses and the intensity of the applied voltage as a result of the increase in the ionization process of silver in water.

In General, a larger number of experimental data would be required for optimizing the performance efficiency of the electrodes in solid oxide fuel cells (SOFC), as it was likely to involve many complex chemical and physical reactions. Therefore, in this study, we have attempted the artificial intelligence (AI) technique for analyzing the performance of the anode and cathode electrodes of SOFC under various key parameters that normally influences the efficiency of the electrodes. Since the cost of SOFC elements is expensive, computational trials with the aid of AI would not only be curtailing the preparation cost but also ensures less time consumption. Among the variety of AI methods available in the literature, the Support Vector Machine (SVM) appears to be one of the excellent and effective machine learning techniques. Hence, we have developed a SVM model and predicted the maximum current density and power density of Nickel oxide-samarium-doped ceria (NiO-SDC) composite anode and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode electrodes of SOFC. The input parameters such as stack temperature, supply voltage were supplied to the SVM model and obtained maximum current density and power density as output and it decides the working performance of the electrodes. We have also predicted that the maximum current density and power density of 1160 mA cm2 and 225 mW cm2 respectively at 800 °C. To validate the results as predicted from SVM, we have experimented using Yttrium stabilized zirconia electrolyte-supported single cell with our prepared NiO-SDC anode and LSCF cathode which exhibited a maximum current and power density of 1170 mA cm2 and 227 mW cm2 at 800 °C using H2 as fuel. It has been found that that the theoretical predicted data current and power densities of the electrodes from the SVM approach reasonably agrees well with the experimental results.

This paper introduces a new active-neutral-point clamped (ANPC) seven-level inverter with a switched-capacitor technique. The introduced inverter generates a seven-level ac output voltage with a maximum voltage-boosting gain of 1.5. Also, a simple modulation technique was proposed, where the capacitors voltages are naturally balanced by the series-parallel connection of the input voltage source. Compared with seven-level inverter topologies, the proposed topology is simpler and its control system does not requires sensors or balancing circuits to stabilize the dc-link voltages. Additionally, the dc-link voltage requirement is reduced by 33.33%, eliminating the need for an intermediate dc-boosting stage and making the introduced inverter a good candidate for applications such as photovoltaic panels and full-cells systems, both characterized by a low input voltage. The operation and performance of the proposed topology is validated through simulation and experimental results.

The project is envisioned to convert DC output combined from the micro grid as the common dc bus into AC voltage. S3 inverter is used to obtain appropriate sine wave as output. Inverter generally has high Total Harmonic Distortion (THD) and by using our implementation on this project, less THD could be achieved. This topology of the inverter has only three semiconductor switches, one with a large frequency and another with a fundamental frequency. Therefore, the inverter is designated the S3.

Some studies verified that the pulsed current charging technique could extend the battery lifetime and improve the charging performance of lithium-ion batteries. However, some researchers are skeptical of this opinion because their studies have not found any advantages of pulsed current charging over conventional Constant Current (CC) charging. Positive Pulsed Current (PPC), the most common pulsed current mode, was selected for the investigation in this work. The effect of the PPC with various parameters, including the duty cycle, amplitude, and frequency, on the performance and lifetime of lithium-ion batteries, are investigated by experiments. According to the experimental results, the charging speed, charging capacity, and maximum rising temperature are mainly determined by the duty cycle and amplitude of the PPC. The battery lifetime with PPC under the frequency range from 0.05 Hz to 2 kHz has been verified to be extendable. Moreover, the battery lifetime extension can even be over 100% under a specific frequency PPC compared with CC charging. This is the first work that summarizes the law of the pulse frequency on battery lifetime extension. In the future, the pulsed current is expected to be used in fast charging technologies without compromising battery lifetime.

Here suggests the formation of a pair of CIBCs with raised performance for solar application by employing maximum power point tracking method. The suggested two level CIBCs contains a pair of interlaced boost converter (CIBC) coupled in concatenation to gather the utmost power from sunlight and to supply a rise in output voltage with low ripple. The simulation of PV system and power converters has been done MATLAB/simulink.

The aim of this paper is to have comparative analysis of open loop control provided for solar panel and the non isolated control provided for solar panel. Solar current and Voltage for the designed panel was determined and the maximum voltage and current are determined for the designed panel. Maximum efficient processing system has been determined by accounting two controllers for the designed solar panel.

One of the most serious issues that requires special attention is the protection of distribution networks. Using the proper protective equipment improves the safety of the power distribution network during fault conditions. Fault current limiter (FCL) is a type of modern preservation system used to protect power networks and equipment. The voltage restoration of buses during faulty conditions is one of the main concerns of power networks. A group of coordinated DC reactor type fault current limiters are designed and tested in this study to protect the network and restore its bus voltage during the fault period. The proposed FCLs coordination strategy is modelled and simulated in the MATLAB platform, and the results are validated.

Due to active power demand in the distributed power system, the large voltage deviation appears in the grid network. The battery energy storage system is optimal solution to support the active power when it is needed, which improves the voltage stability. To maintain the accuracy in the active power injection, the modified hysteresis current control of multilevel converter for grid connected battery storage system is proposed in this paper. It supplies accurate active power by estimating the exact reference current from the grid voltage at every sampling period. This novel control mechanism ensures that there will not be any mismatch in the active power requirement and supply; thereby it enhances the quality of grid under nay situation. The detailed control block diagram is addressed to generate the required PWM signals. And also, the detailed operating waveforms are discussed in this paper. The equivalent circuit of power transfer to grid is also reported in this paper. Mathematically it gives that the proposed approach can inject the actual active power needed by the system. To validate the proposed modified hysteresis current control scheme of multi-level converter, the entire simulation study has been developed and carried out in PSCAD/EMDTC software. The measured results observed and presented in this paper and also it confirms that the proposed has practical feasibilities to implement in the real system.

This paper proposed a modular three-phase multilevel inverter configuration using level doubling network (LDN). This configuration doubles voltage levels in each phase, preserving modularity and without increasing the device count and ratings. Preserved modularity and switching redundancies of the configuration support inverter fault-tolerant ability. A simple control algorithm imposing a popular level-shifted carrier arrangement is used to implement the proposed configuration. Performance of the proposed configuration and PWM is analyzed and validated for multiple case studies in the Simulink environment using MATLAB.

Unified Power Quality Conditioner (UPQC) is a cutting-edge Custom Power Device (CPD) that is being used to improve power quality in the distribution network. UPQC contributes to the distribution network by compensating for both voltage and current-related power quality disturbances. Its control strategy in unbalanced and distorted weak grid conditions is of particular interest for research. In addition, the performance of UPQC in the presence of unbalanced and non-linear harmonic loads is critical for maintaining desirable power quality. This paper investigates the implementation of UPQC control strategies and algorithms for improving power quality (PQ) and proposes a versatile control strategy to improve UPQC performance. When tested on a critical distribution network, the proposed dynamic control strategy provides better steady-state and dynamic response. Models developed in MATLAB/SIMULINK are used to validate the proposed control scheme.

In this paper, Sliding Mode Controller-based Distribution Static Compensator (DSTATCOM) is proposed for enhancement of power quality in the distribution network. The DSTATCOM plays a vital role to enhance the quality of power in the distribution network with linear and nonlinear loads under non-stiff sources. During the load disturbance in the systems, there is a sudden variation of voltage in DC link capacitor voltage connected with compensating device. The performance of DSTATCOM purely depends on the capacitor voltage level during load variation. It should be maintained within the prescribed limits. In general, the conventional controller is used in the converter to control dc-link capacitor voltage. Through, the conventional controller like PI transient response is still slow. Due to this reason, the harmonic elimination, load balancing, and reactive power compensation process are not satisfactory during different load variations in the distribution systems. To overcome these problems sliding mode controller is proposed in the control circuit for the proper operation of the compensator. The sliding mode controller regulates the DC link capacitor voltage to generate required reference currents. The reference currents play a vital role for switching pulse generation and control of DSTATCOM during various load disturbances. Sliding mode controller is designed to limit variation of DC-link voltage within limits. The proposed technique is modelled and its performance is simulated in MATLAB/SIMULINK platform and results are shown to validate the design and control of DSTATCOM under various load disturbance.

The most important variables to consider in the design of antennas for RFED applications and effective communications are low cost, low profile, and reduced size. The dipole antenna, often known as a dipole aerial, is the most basic and widely used type of antenna. Among other antennas, this is one of the most straightforward antenna layouts. It may be achieved by applying a sinusoidal voltage differential between two thin metallic rods. The dipole antenna is a particularly important type of RF antenna that is frequently used for radio transmission and reception. For many types of antennas, this antenna can be employed as a radiating or driving element. This Dipole antenna may be used in the radio frequency spectrum sections HF, VHF and UHF. The major advantage of a dipole antenna is that it can serve as both a broadcast transmitter and receiver. So, to obtain the most crucial factors, we'll design an antenna in COMSOL Multi Physics and display the results as Radiation patterns.

An innovative control method for 1-phase DSTATCOM incorporating communication network is discussed in this paper to obtain the coordinated control between the Distributed Generators and Compensators. The methodology is intended for micro grid supplying loads with feeders traversed physically distant apart from each other. The anticipated reactive compensation is constructed on confined measurement and the transmitted power through the cables. It ensures that the discussed approach minimizes the voltage level more efficiently while sustaining the voltage control even after a high-level dissemination of the DGs. The MATLAB simulations carried over thearbitary network confirm the DSTATCOM outstanding performances with different operating situations like utility side, mid of the feeder and end of the feeder. The impact of communication node breakdown is analyzed at various nodes and the significance of communication in loop control is validated through an arbitrary 5-bus system.

This paper discusses the analysis of a Quasi Z source inverter with a trouble-free boost control tactic for renewable energy applications. The non-availability of uninterrupted renewable energy sources in atmosphere weather conditions raises variation in output voltage and currents. This may affects the performance of conventional inverters with potential source (VSI), current source connected (CSI) and impedance source inverter (ZSI). To overcome the drawback of VSI, CSI and ZSI a quasi-Z source inverters (QZSI) are used. The QZSI performs multiple operations such as DC-to-DC, AC-to-AC, AC-to-DC and DC- to-AC conversions. Also, it may be used for each buck and boost operation, using the shoot through state. The QZSI is derived from the ZSI topology, with a minor modification of the impedance network and overcomes the troubles facing in ZSI. The design construction and simulation study of quasi-Z source inverter is performed using MATLAB/Simulink environment.

This paper investigates a single-phase multilevel dc-ac converter composed of four series/parallel-connected H-bridges with floating capacitors. System model, pulse-width modulation (PWM) strategies, and a control strategy have been presented. An important variable is the control of the dc-links voltages in the floating capacitor. Thus, an individual balancing of dc-links voltages using auxiliary variables and redundant voltage vectors are shown in this work for different dc-link voltage ratios. Simulations and experimental results with several power levels show how the operating characteristics.