Power Electronic Converter Systems Research Articles

Comparative Analysis and Performance Evaluation of Dual Active Bridge Converter Using Different Modulation Techniques

The development in the renewable energy systems and the necessity of the enhanced grid that includes the conventional energy sources and the renewable energy sources and storage systems have realized the importance of power electronics conversion systems. These interfaces are crucial for enhancing the efficiency as well as the control in bi-directional power flow. The use of HEVs as a means of preserving the future supply of fossil fuels, as well as the need for improving the efficiency of the power electronics interfaces required for efficient power management between the two energy sources of the vehicle, is discussed. Furthermore, the improvements in the Uninterruptible Power Supply (UPS) systems and regenerative power systems also require sophisticated power electronic conversion systems. To address these issues of modern technologies, the Dual Active Bridge (DAB) converter comes in as a potential solution. In this paper, several modulation techniques employed in DAB converters are discussed and compared in detail in order to find the best approach to control the converter’s performance in the whole range of its operation. The paper also presents an enhanced modulation strategy applied to DAB converters and built with FPGAs and MPC to minimize the power loss. This proposed optimization technique is more general and easier than the current ones. The performance of the converter is assessed in terms of efficiency, current stress, and the power of backflow, in addition to the proposed optimization and modulation techniques. The article also looks at the closed-loop performance under step load fluctuations and circuit performance as well as efficiency.

Testing Algorithms for Controlling the Distributed Power Supply System of a Railway Signal Box

Trends in the use of renewable energy sources to power buildings do not bypass objects for which maintaining a power supply is critical. This also applies to railway signal boxes. The aim of the research work was to test the multisource power supply system for a railway signal box with power electronic converter systems and a DC bus, built as part of the research project. The assumption for powering the railway signal box building was to use renewable sources, energy storage devices, and a 3 kV DC traction network as the second required power supply grid. Both power grids were connected by power electronic converters, and the power values of the converters were set based on the calculated power balance values using the values measured at the system nodes and the set constraints. The tests primarily tested the response of the power supply system to changes in load power and power generated by the photovoltaic source, as well as the charge level of the energy storage devices. The correctness of the control algorithm’s operation was assessed based on the recorded power values in the power supply system nodes. The tests were carried out for 60 scenarios that covered all normal and emergency operating conditions. During the tests, delays in response to changes in the power supplied to the converters and the values of circular power flow between the power grid connections were recorded. The recorded delays ranged from 2 to about 50 s and the circular power flows did not exceed 1500 W. Based on the results of the tests, it was found necessary to improve the power measurement system in the power supply system nodes and to improve the quality of communication and the transmission time of measurement data transmission time.

A Comprehensive Investigation into Bidirectional DC-DC Converters with Soft Switching for Electric Vehicles

Electric vehicles (EVs) are one of the the promising solutions for the environmental issues such as carbon emission and global warming. The high voltage traction battery in EVs is charged from utility grid by an EV charger. The Society of Automotive Engineers (SAE) standardize EV charges into two categories on-board chargers and off-board chargers. Usually, the on-board chargers are located inside the vehicle whereas, off-board chargers are not mounted on the vehicle. For onboard chargers, size and power density of charger become a prior matter of concern. The only way to reduce the size of a converter and thereby increase the power density is to operate power electronic conversion system (PECS) at very high switching frequency (HSF) resulting in reduced size of magnetic component in the charger configuration. However, HSF operation may lead to a high electromagnetic interference (EMI), loss in switch and switch duty. The work in this paper is focused on the development of high frequency bi-directional DC-DC converter (BD2C) stage priory used in on-board chargers due to distributed sources of energy as well as to manage the power distribution in the configuration. The power electronic BDCs are derived from boost and buck unit. The boost derived converter are current fed converters and offers advantages in terms of inherent voltage gain, short circuit protection and lower input current ripple. The voltage spikes across switches, high rated device selection, hard switching, snubber and auxiliary circuit requirements are some of the undesirable factors. This occurrence happened due to unbalance power transfer by the power electronics converter. Similarly, voltage fed converter offers good voltage control during power transfer.

Reliability prediction of a 30 kW power electronics converter

This paper describes the challenges involved for predicting reliability of power electronics converter systems and provides recommendations. To this aim, a case study for modelling a 30 kW inverter platform for power quality applications is presented. The converter is based on different circuit boards that were analysed by electronics reliability prediction. In addition, fans and an IGBT module were modelled by a Weibull failure distribution. The study underlines that the reliability assessment of complex electronics is a persisting challenge.

Parasitic Capacitive Couplings in Medium Voltage Power Electronic Systems: An Overview

Recent development within the field of medium voltage wide-bandgap semiconductor devices are drawing the attention from both researchers and industries, due to the demanding requirements for more efficient high-power energy conversion. The rapid development has entailed an increased awareness of the negative impact of increased rate of change in voltage, d vd t, and its derived issues caused by the inevitable parasitic capacitive couplings. This paper is dedicated to present an overview of the parasitic capacitive couplings in high-power medium voltage power electronic converter systems, using an example reference system enabled by medium voltage SiC MOSFETs. The definitions of capacitive couplings are presented and the impacts raised by parasitic capacitive couplings are reviewed. In addition, the similarities of different capacitive couplings introduced by components in practical medium voltage systems are presented and summarized. Lastly, the challenges and future work with respect to parasitic capacitive couplings in medium voltage power electronics converter systems are shared from the authors' perspective.

Optimized Non-Integer Load Frequency Control Scheme for Interconnected Microgrids in Remote Areas with High Renewable Energy and Electric Vehicle Penetrations

Renewable energy systems (RESs) have introduced themselves as vital solutions for energy supply in remote regions, wherein main utility supply systems are not available. The construction of microgrid (MG) systems is useful candidate for proper control and management with hybrid RESs. However, RESs-based MGs face reduced power system inertia due to the dependency of RESs on power electronic converter systems. Accordingly, preserving nominal operating frequency and reduced deviations in tie-line power are crucial elements for proper operation of interconnected MGs in remote areas. To overcome this problem, load frequency control (LFC) systems have proven featured solutions. Therefore, this paper proposes a new non-integer LFC method based on the fractional order (FO) control theory for LFC in interconnected MGs in remote areas. The proposed control is based on the three degree of freedom (3DoF) cascaded 1+proportional-integral-derivative-accelerated (PIDA) controller with FOPI controller, namely 3DoF 1+PIDA/FOPI LFC scheme. The proposed 3DoF 1+PIDA/FOPItakes the advantages of the accelerated term of PIDA control to improve power system transients, regarding maximum overshoot/undershoot and settling times. Additionally, it employs outer loop to reduce errors and faster inner loop to mitigate disturbances effects. The contribution of plug-in controlled electric vehicles (EVs) are considered to enhance the frequency regulation functions. An optimized design of the proposed 3DoF 1+PIDA/FOPI LFC scheme is proposed using the newly developed hybrid equilibrium optimizer (EO)-slime mould optimization (SMA) algorithm (namely EOSMA optimizer). The EOSMA combines the features of the EO and SMA powerful optimization algorithms. A two interconnected MGs in remote areas with RESs and EVs inclusions with high penetration levels is selected to verify the proposed 3DoF 1+PIDA/FOPI LFC scheme and the EOSMA optimizer. The results show high ability of the proposed controller and design scheme to minimize MGs’ frequency and tie-line power fluctuations and to preserve frequency stability and security.

A flexible power electronic converter system with rapid control prototyping for research and teaching

A flexible power electronic converter embedding a rapid control prototyping platform suitable to be applied in research test setups and teaching laboratories is proposed and described in this paper. The electronic system is composed of three subsystems, namely, i) three half-bridge power boards, ii) a dc-link capacitor bank with a half-bridge power module for active dc-link control, iii) an interfacing board, called motherboard, to couple the power modules with a control unit, iv) a digital control unit with rapid control prototyping functionalities for controlling power electronic circuits. Power modules integrate sensors with related conditioning circuits, driving circuits for power switches, and protection circuits. Conversion circuits exploit GaN electronic switches for optimal performance. The architecture and implementation of the system are described in detail in this manuscript. Main applications are in the implementation of conversion circuits for supplying arbitrary ac or dc voltages or currents, testing of new control algorithms for power electronic converters, testing of systems of electronic converters in, for example, smart nanogrids or renewable energy applications, training of undergraduate and graduate students.

Conversion and SISO Equivalence of Impedance Model of Single-Phase Converter in Electric Multiple Units

The direct-quadrature (DQ) model, mirror-frequency impedance (MFI) model, and harmonic state-space (HSS) model are three main modeling methods for single-phase power electronic converter systems. These models are established under three different frameworks: the dq-frame, the mirror-frequency frame, and the extended harmonic domain frame. The purpose of this article is to demonstrate how to create a unified modeling framework and to provide an unambiguous relationship between the impedances in these three domains. The unified model framework facilitates flexible and scalable modeling by making different models to be easily interconnected with other systems. In addition, to simplify the stability analysis and impedance measurement process, the three modeling methods are reduced to first-order single-input and single-output (SISO) equivalent models, respectively, based on the model reduction technique. Finally, the impedance measurement and stability analysis results of electric multiple units (EMUs) accessed vehicle-grid system demonstrate the accuracy of the conversion and SISO equivalence technique.

Inverse Application of Artificial Intelligence for the Control of Power Converters

This article proposes a novel application method, inverse application of artificial intelligence (IAAI) for the control of power electronic converter systems. The proposed method can give the desired control coefficients/references in a simple way because, compared to conventional methods, IAAI only relies on a data-driven process with no need for an optimization process or substantial derivations. Noting that the IAAI approach uses artificial intelligence to provide feasible coefficients/references for the power converter control, rather than building a new controller. After illustrating the IAAI concept, a conventional application method of artificial neural network is discussed, an optimization-based design. Then, a two-source-converter microgrid case is studied to choose the best droop coefficients via the optimization-based approach. After that, the proposed IAAI method is employed for the same microgrid case to quickly find good droop coefficients. Furthermore, the IAAI method is applied to a modular multilevel converter (MMC) case, extending the MMC operation region under unbalanced grid faults. In the MMC case, both simulation and experimental online tests validate the operation, feasibility, and practicality of IAAI.

Fault Diagosis of CHB Inverter Using Machine Learning

Renewable energy has gained popularity due to depleting natural resources and escalating fossil fuel and nuclear pollution. Power electronic engineers design grid-connected power conversion systems. MLIs provide more power and solutions. Cascaded H-Bridge (CHB) MLIs start with two or more 3L single-phase H-bridge inverters. Each H-bridge may produce three separate voltage levels. Combining the separated dc voltage sources produces a stepped output voltage with a step size equal to the magnitude of the connected sources. The present work develops a method for detecting and resolving switch failures in a three-phase CHB inverter, ensuring system dependability and allowing for system redundancy. The recommended approach uses Wavelet transform to extract features, then Decision Tree classifier to detect and characterise defects. Increased classification accuracy shows the DT-based fault diagnosis system's efficiency in identifying inverter switch faults.

Testing Reliability of Electronic Components and Converters Is Vital for Systems [From the Editor

<fig orientation="portrait" position="float" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <graphic orientation="portrait" position="float" xlink:href="bindra-3221629.tif"/> </fig> In modern energy production, storage, transmission, distribution, and consumption, power electronics has been playing a crucial role. Because power converters are critical links in electrical energy systems, impacting system security, safety, energy efficiency, and cost, the reliability of power electronic components and converter systems has become very important in these applications. In short, the reliability of energy systems is completely dependent on the reliability of electronic components and power converters. Consequently, testing is now considered a vital reliability engineering tool to investigate failure mechanisms, identify weakest points, and demonstrate robustness margins in components and converters. However, reliability testing is not simple and requires time, right amount of data, state-of-the-art testing facilities, and understanding of uncertainties of failure mechanism.

Application-Oriented Reliability Testing of Power Electronic Components and Converters

Power electronics have been and will continue to be an enabling technology for energy production, storage, transmission, distribution, and consumption. Power electronic converters are usually the critical links in electrical energy systems, affecting system security, safety, energy efficiency, and cost-of-ownership. As a result, the reliability requirements for power electronic components and converter systems generally become more stringent, for example, in e-mobility, renewable energy generation, and power system applications. Testing is one of the vital reliability engineering tools to investigate failure mechanisms, identify weakest points, and demonstrate robustness margins. It contributes to reliability growth along the product development process and the likelihood of failure reduction in field operation. The required resources (i.e., testing time, sample size, and testing facility) and the relevance of the testing results to field operation are two crucial considerations in implementing a reliability test. This article introduces the emerging application-oriented testing concepts and facilities through several component-level and converter-level examples.

Power Converter Topologies for Grid-Tied Solar Photovoltaic (PV) Powered Electric Vehicles (EVs)—A Comprehensive Review

The transport sector generates a considerable amount of greenhouse gas (GHG) emissions worldwide, especially road transport, which accounts for 95% of the total GHGs. It is commonly known that Electric vehicles (EVs) can significantly reduce GHG emissions. However, with a fossil-fuel-based power generation system, EVs can produce more GHGs and therefore cannot be regarded as purely environmentally friendly. As a result, renewable energy sources (RES) such as photovoltaic (PV) can be integrated into the EV charging infrastructure to improve the sustainability of the transportation system. This paper reviews the state-of-the-art literature on power electronics converter systems, which interface with the utility grid, PV systems, and EVs. Comparisons are made in terms of their topologies, isolation, power and voltage ranges, efficiency, and bi-directional power capability for V2G operation. Specific attention is devoted to bidirectional isolated and non-isolated EV-interfaced converters in non-integrated architectures. A brief description of EV charger types, their power levels, and standards is provided. It is anticipated that the studies and comparisons in this paper would be advantageous as an all-in-one source of information for researchers seeking information related to EV charging infrastructures.

Effect of Temperature Change on Acoustic Emission Signal in IGBT Transistors of Marine Propulsion System Converters

The article presents the results of tests related to failure analysis and finding ways to diagnose used semiconductor elements, among others, in power electronics converter systems on vessels and offshore facilities (drilling and production rigs and wind turbines). Diagnostic relationships were found between the temperature change in the above systems and the signals generated in the form of elastic waves of acoustic emission. The authors confirmed the influence of the transistor’s working temperature on its amplitude-frequency spectrum of acoustic emission signals emitted. The range of ‘safe temperatures’ was considered which means temperatures that do not directly affect the damage of the component.

Analysis and Design of a High-Efficiency SiC MOSFET 6-Phase Boost Rectifier

In this paper, the analysis and the design of a high-efficiency power electronic conversion system for offshore wind applications are presented. This system is composed of a 6-phase AC–DC converter based on the SiC power semiconductors, to be used to control the achievable power from the wind turbine electrical generator. Thanks to the phase redundancy, the proposed boost rectifier is suitable for applications where reliability and fault tolerance capability are the main targets. To select the appropriate power semiconductor devices, voltage and current ratings have to be determined. After that, the power loss equations are derived in order to evaluate the conversion efficiency. To design the appropriate DC-bus capacitor configuration, an analytical investigation is carried out by estimating the DC-bus RMS current and the voltage ripple. Finally, the thermal sizing of the system is calculated to identify a suitable heatsink. To validate the proposed analysis, the analytical results are compared to simulation ones using the Plexim/PLECS tool in the MATLAB/Simulink environment. For further validation, a prototype of the converter is built and the experimental results are carried out. The results demonstrate that the peak efficiency of the 6-phase boost rectifier can reach 98% at 100 kHz switching frequency.

Single phase multifunctional integrated converter for electric vehicles

In this paper, a single phase multifunctional integrated converter is proposed for electric vehicles (EVs) with single stage power conversion. The main objective of the proposed topology is to reduce the weight, size, and cost of the power electronic converter system used in EVs compared to the existing topologies that are already available in the industries. The novelty of the proposed topology includes: (i) single converter for charging, propulsion and regenerative braking; (ii) reduction of number of switches to reduce the switching and conduction losses; (iii) improving the efficiency by reducing the value of inductor; (iv) power factor correction for AC grid; and (v) improving the total harmonic distortion of the grid current. The complete analysis of the various modes of operation of the proposed topology is analyzed and implemented through MATLAB/Simulink software simulation and a power factor of 0.9999 and a current total harmonic distortion (THD) of 2.16% is achieved. The proposed topology is also compared with the existing topologies in terms of number of switches, diodes, inductors and capacitors used.

High Performance DC-to-AC Converter Using Snubberless H-Bridge Power Switches and an Improved DC-to-DC Converter

This paper presents the analysis, modeling, simulation, and implementation of a high performance DC-to-AC (DC-AC) converter. The system comprises of a combination of DC power source, stress less DC-to-DC (DC-DC) voltage converter, two snubberless power switches, and control unit. The system is portable, has a two-stage input voltage transformation and amplification with no transformer and occupies less space unlike the classical two-stage inverter systems. In addition, the system produces a constant DC boosted voltage with less stress on both the source and DC storage capacitor which are not found in conventional converters. The proposed power electronic converter system produced the following results: pure sine voltage and current waveforms, total harmonic distortion (THD) of 4.294%, power output of 5740W, efficiency of 98.9%, power loss of 60W and fast dynamic response. The target areas of applications of the proposed converter are in medium and small scale industries.

Energy Conversion System and Control of Fuel-Cell and Battery-Based Hybrid Drive for Light Aircraft

The paper presents a power electronic conversion system and its control for a fuel cell and a battery-based hybrid drive system for a motor glider. The energy conversion system is designed in such a way that the fuel cell gives power equal to the electric drive power demand for horizontal flight, whereas during motor glider take-off and climbing, the fuel cell is supported by the battery. The paper presents the power demand related to the assumed mission profile, the main components of the hybrid drive system and its holistic structure, and details of power electronics control. Selected stationary experimental test results related to the energy conversion and drive system are shown. Some results related to the aircraft tests on a runway are presented.

Velocity control of an induction motor fed by an inverter-DC/DC Buck power electronic converter

We present, for the first time, a formal stability proof for velocity control in induction motors fed by three-phase inverter-DC/DC Buck power electronic converters as power amplifier. Although our result is local, we take into account the complete dynamics of the induction motor and the three-phase inverter-DC/DC Buck power electronic converter system. Despite the complexity of the problem, our proposal is based on several proportional-integral control loops. The key to achieve this result is a novel passivity-based approach that we call energy-based control having a number of advantages over previous passivity-based approaches in the literature. An important problem that is considered is that of an unbalanced three-phase voltage source. This condition appears during the transient periods in the inverter-DC/DC Buck power electronic converter system. This is important because the standard models of induction motors are obtained under the assumption of a balanced three-phase voltage source.

Design of a model predictive controller for grid connected microgrids

Power electronics converter and inverter systems for microgrid operations are always stochastic in nature. When the system operates in grid tied mode the user always faces a steady state residual p...