Semiconductor Switching Devices Research Articles

High Frequency Modeling of Electric Machines Using Finite Element Analysis Derived Data

The use of wide band gap semiconductor switching devices in electric machine drives leads to a significant increase in power density and efficiency compared to conventional silicon-based solutions. However, this technology also presents challenges for the insulation design of electric machines since partial discharges (PDs) may occur due to high peak voltage stress as a result of fast and high frequency switching. To evaluate the risk of PD, it is necessary to understand the voltage distribution within the windings and associated insulation of an electric machine during converter operation. To this end a suitable high frequency model of the machine windings capable of predicting the internal voltage distribution is required. This paper proposes a method of constructing such a model based on finite element analysis (FEA) derived data. The FEA data used to parameterise the model in this work incorporates frequency dependant properties and homogenisation techniques to produce data which captures the high frequency behaviour of the machine. The developed model is compared with measurements in both frequency and time domains, demonstrating the utility and accuracy of the model.

A Modular Push–Pull–Flyback High-Voltage Pulse Generator for Electric Field Emulation During a Lightning Strike

To meet the requirements of simulating the electric field during a lightning strike, there is an urgent need for a voltage pulse generator that generates voltage pulses that are equivalent to the electric field during the lightning strike. A new pulse generator structure based on a push–pull DC–DC converter and a flyback converter is proposed. The pulses produced by the proposed generator have a variable voltage rise rate, and a modular design is used for the generator. Each module works independently and is powered by an exclusive lithium battery, which avoids the problems of the need for a high-voltage DC source, current sharing, and a complex control strategy in existing generators. The electrical behavior of the proposed generator during the switching transient is analyzed considering the effects of both the semiconductor switching device (insulated-gate bipolar transistor) and transformer. The method of selecting the specifications of each component and the method of designing the core component are presented in this study. The accuracy of the transient model and the feasibility of the proposed generator are verified in experiments, and a 60-stage prototype that produces pulses with amplitudes in excess of 1 MV, widths of 1–3 ms, and a variable voltage rise rate is developed.

The Development of Solid-state Pulse Generator based on Marx Circuit with Chopping Switch

A solid-state pulse source is mainly formed by replacing the spark switch in a traditional pulse source with semiconductor switch device. Compared with conventional gas switch devices such as spark switches, semiconductor switch devices have the advantages of high work repetition frequency, long service life, small size, high efficiency, high reliability, easy control, and active shutdown. However, there are still problems, such as the solid-state switch being easily broken down by high voltage, the rising and falling edges of the pulse being slow, and the loss is enormous. In this paper, a solid-state pulse generator based on Marx with a chopping switch circuit is developed, which effectively solves the above problems. The pulse generator comprises DC power, a switching power circuit, a Marx circuit with a chopping switch, a serial port touch screen, and an optical fiber transmission circuit.

Vibration Suppression of a Specific Harmonic Component by Teeth Flux Density Control Using Multi-Phase MATRIX Motor

In recent years, progress in power semiconductor switching devices has created more additional advantages that can be realized using multi-phase inverter-fed motors. The authors propose a MATRIX motor to realize electric motors with higher functionalities than conventional electric motors. Since the MATRIX motor is driven by H-bride inverters connected with each phase winding, it has a high degree of freedom in control. Moreover, these inverters can change their connections to different phase coils to realize a wide operating range. The voltage equation of each mode can be expressed using the transformation matrix when the winding connection is changed. Therefore, we call the proposed motor MATRIX motor. In addition, since motors are being applied to various applications that operate within proximity of people, further quietness of the motor is required. In this paper, we propose a method to suppress vibration caused by a specific harmonic order radial direction electromagnetic force via teeth flux density control using the MATRIX motor. The specific order radial force and vibration are suppressed by utilizing two features of the MATRIX motor. One is a high degree of freedom of current control owing to multi-phase drive and the other is local flux density observation. The effectiveness of the proposed method was clarified using experimental results.

A Single-Stage Quasi-Z-Source-Based 5-Level Grid-Tied PV Inverter With Reduced Leakage Current

This article presents a single-staged quasi-z-source (qZS)-based 5-level inverter topology for grid-tied photovoltaic applications. In this topology, two symmetrical qZS networks with a single dc source are fused with a 5-level hybrid inverter. When compared to the existing qZS-based 5-level inverters in the literature, the proposed power converter employs fewer semiconductor switching devices, enhancing its reliability. The objectives of boosting the voltage of the input PV source, as well as the synthesis of a 5-level output voltage are achieved with a modified level-shifted PWM scheme. Furthermore, closed-loop control schemes are implemented for the proposed power converter in both standalone and grid-tied modes of operation and its dynamic performance is assessed. The operability of the proposed power converter in the grid-tied mode of operation is demonstrated by injecting active power into the grid at the unity power factor (UPF). It is also shown that the proposed topology is capable of reducing the leakage current, which is one of the major safety concerns in transformerless PV systems. Experimental results obtained with a laboratory prototype, validate the operating principles of the power converter in both standalone and grid-tied modes of operation.

An Enhanced Fault-Tolerant and Autoreconfigurable BLDC Motor Drive for Electric Vehicle Applications

Semiconductor switching devices are susceptible to open-circuit (OC) and short-circuit (SC) faults, adversely affecting the reliability of power converters. This article proposes a multiple-switch fault-tolerant and autoreconfigurable brushless direct current (BLDC) motor drive configuration, suitable for electric vehicle applications, owing to its enhanced reliability. The proposed power circuit configuration, along with its fault diagnostic algorithm, is capable of achieving fault tolerance against multiple OC and SC faults. The proposed drive configuration is capable of delivering rated power to the BLDC motor even after the development of several faults in the power semiconductor switching devices. In this power converter, additional switching resources, provided to achieve fault tolerance, get connected only after the occurrence of faults. This feature avoids their unnecessary exposure before the occurrence of faults. Furthermore, the proposed topology requires fewer sensors to implement the fault diagnostic algorithm resulting in reduced cost and increased reliability. This article also presents an analysis that assesses the cost-effectiveness of the proposed drive configuration, which reveals that the additional cost to implement the proposed topology is not more than 6% of the total raw material cost of the conventional BLDC motor drive. Simulation and experimental studies validate the concept of the proposed drive configuration.

A single-phase level-shifted duty controlled multilevel rectifier-based EV charger for wide output voltage range

Nowadays, electric vehicles (EVs) are gaining popularity with customers and as an environmentally-friendly option owing to the rise in petroleum prices and pollution, respectively. The battery is the prime source of power for EVs. This paper presents, a level-shifted duty controlled multilevel power factor correction (PFC) AC-DC converter, followed by a phase-shifted full-bridge converter (PSFBC) as an efficient charging solution for EVs. The adopted topology uses fewer semiconductor switching devices than traditional multilevel converters, which minimises switching losses, making it a good choice for a compact EV charger. Complete system design is carried out for a single-phase, 3.3 kW, EV charger, with 220 vrms AC input and 48-72 V DC output voltage for batteries. This EV charger has improved the system reliability and efficiency, along with the near-unity power factor (UPF) in compliance with the international IEC-61000-3-2 PQ standard. MATLAB/Simulink and experimental results are presented to validate the aforementioned functionalities of this EV charger.

A design optimisation tool to minimise volume and failure rate of the modular multilevel converter and the thyristor-controlled rectifier

The unfolding of MVDC (Medium Voltage DC) systems has the prospects to enable the incorporation of power electronic converters with higher power density and reliability. A tool with an integrated design approach is required to minimise the overall system volume by identifying optimal components. In this paper, a component-level early-stage design tool has been developed to attain the minimum achievable volume and failure rate for MVDC power converters. The developed tool optimises the choice of semiconductor switching devices, required heatsink, and other passive components (including dc-link filters and inductors) to minimise failure rate and overall converter volume. The optimisation algorithm employs the non-dominated sorting genetic algorithm (NSGA-II) to evaluate designs based on developed fitness functions. The design tool demonstrates the trade-off when evaluating multiple converter topologies and helps make an informed decision. A comparative study between two converter topologies shows the outcomes in terms of targeted metrics (volume and failure rate). This tool is expected to benefit early-stage design to perform trade-off studies among power electronic converter topologies based on key metrics like volume and failure rate.

A Single-Phase Compact-Sized Matrix Converter with Symmetrical Bipolar Buck and Boost Output Voltage Control

The development of single-phase symmetrical bipolar voltage gain matrix converters (MC) is growing rapidly as they find their application in power systems for dynamic restoration of line voltages, high voltage AC–DC converters, and variable frequency controllers for many industrial processes. However, the existing trend in matrix converter technology is a buck–boost operation that has inherently serious issues of high voltage and current surges or stresses. This is a big source of the high voltage and current rating of semiconductor switching devices. There is also a problem of high ripples both for voltage as well for current, requiring large size of filtering capacitors and inductors. The non-symmetrical control of the voltage gain increases the control complication. A large count of operating transistors is critical regarding their cost, size, and power conversion losses, as the space and cost required by their gate control circuits are much larger than the size and cost of the switching transistors. Thus, in this research work, a new single-phase MC is introduced only employing six fully controlled switching devices, ensuring similar operation or outputs as is obtained from the existing topologies that require the use of eight or more fully controlled switching devices, and the reduction by two or more switching transistors helps to compact the overall size and lower the overall cost. The separation in its voltage buck and boost operation enables smooth control of the voltage gain through duty cycle control. The low values of the voltage and current surges reduce the power rating and losses of the switching devices. The flow of the current in the filtering inductor is kept unidirectional to avoid the current interruption and reversal problem once the operation of the converter is abruptly switched from inverting to non-inverting and vice versa. All these factors are comprehensively detailed through the circuit’s description and comparative analysis. Simulation and practical results are presented to confirm the effectiveness of the developed circuit topology.

Smart Hybrid Active Power Filter Power Quality Improvement

Filters are devices that remove undesirable or polluting particles from a required environment. Filters are used to ensure the purity of electrical power in electrical systems. Power filters are used to handle power quality concerns such as power factor, voltage stability, and harmonics. There are two types of filters: passive filters and active filters. The current waveform is injected by the active filter in response to the recognized harmonic in the unit. The active filter is made up of electronic semiconductor switching devices. It takes current from an external source (typically DC) and injects it into the system as a specified current waveform to eliminate harmonics. The ability to give signal gain through amplification and lower output impedance are two major advantages of active filters. Active harmonic filters have seen numerous adjustments and upgrades in their implementation to suit specific applications since its introduction. As a result, series and shunt active filters have been implemented to meet the application's needs. Shunt Active Power Filter as a Smart Impedance with proportional resonant (P + R) controller is presented in this work to reduce current harmonics. The results of a MATLAB simulation model are presented in this paper.

Modeling of a Flyback Converter Controlled by an IGBT for Generating a High-Frequency Pulse Voltage

With the rapid development of semiconductor devices, researchers have proposed different types of high-frequency pulse voltage generators based on power electronic converters to meet the requirements of microorganism inactivation, water pollution purification, and piezoelectric and dielectric electroactive polymer drives. The transient modeling of these high-voltage converters aids in understanding the electrical characteristics of the devices and optimizing their performances. This article analyzes the electrical behavior of a semiconductor switching device (i.e., an insulated gate bipolar transistor) used during the switching transient of the converter and constructs an electromagnetic transient model of the flyback converter that considers both the parasitic elements and the ferromagnetic losses of the transformer. The accuracy of the proposed model is then verified by comparing calculation results obtained using the model with experimental measurement results.

THD optimization in 15-level asymmetric reduced switch count multilevel PV inverter using optimization algorithms

Philosophers and industries have focused on designing multilevel inverters, which use significantly fewer power switches and dc sources to achieve high power, low switching, and less harmonic output distortion for medium voltage applications. Even so, these multilevel inverters have some downsides like the use of many electronic components, electromagnetic interference (EMI), bulky driver circuit complexity, significant reverse recovery times, and voltage balancing issues. A modern asymmetrical multilevel inverter with fewer switches and drivers than standard topology is introduced in this article. The powerful analogy addresses traditional inverter topologies of a similar structure. The proposed MLI is relatively simple and easy to extend for many output levels. The proposed design of MLI is implemented for 15 level output with precise and high-quality near sinusoidal waveform using seven switches, three dc sources and three diodes and hence the volume, cost and driver circuit complexity is considerably reduced. The novelty in the proposed topology is that reduced ON state semiconductor switching devices. The output of the MLI is evaluated with the parameter of total harmonic distortion (THD). To minimize the THD, optimization algorithms such as GA, PSO, WOA and HHA were implemented at fundamental switching PWM control method. The comparative analysis of these algorithms on proposed inverter performance is integral for this research. The efficacy of this topology enhances the integration of renewable energy sources.

Common-Mode Current Prediction and Analysis in Motor Drive Systems for the New Frequency Range of 2–150 kHz

Due to the significant advances in fast switching semiconductor devices, harmonic emissions caused by the adjustable speed drives (ASDs) have been changed in terms of frequency range and magnitude. The frequency range of 2–150 kHz has been distinguished as a new interfering frequency range, disturbing the distribution networks. This article proposes a behavioral model of an ac motor to predict the common-mode (CM) current in ASDs. An approach is presented to calculate the parameters of the model, through which the dominant impact of each element at a specific frequency is considered. Moreover, along with the proposed motor model, a system modeling strategy is presented for filter design considerations at an emerging frequency range of 2–150 kHz. To verify the effectiveness of the proposed model, real-time experiments are conducted. The results prove that the introduced model can accurately predict the resonances of the CM loop created by the motor. Consequently, the proposed model is suitable for electromagnetic interference (EMI) filter design covering the 2–150-kHz standard.

Measurement of nanosecond-scaled reverse recovery time by a CPU-based instrument

The dynamic characteristics imply the most important performance of semiconductor switching devices. Herein, a CPU-based instrument is designed for measuring the reverse recovery (RR) time (Trr) and RR charge (Qrr) of low power switching diodes. In the designed electrical system, the reverse voltage pulse is shaped by an emitter coupled logic (ECL) circuit constructed with microwave transistors to raise the pulse edges’ commutating-rate, which is applied to the device under test to yield the RR current (Irr) waveform. This waveform is converted into a voltage pulse with width equal to the RR time by voltage comparator consisted of the other ECL in the sampling circuit. This sampled pulse is sent to analog–digital converter and subsequently into an 89C2052-type CPU for calculating the values of Trr and Qrr, they are monitored by a liquid crystal displayer. The lowest metering range of about 3 ns of Trr is demonstrated, the displayed Trr value agrees with the one observed by oscilloscope, which verifies the design. Besides, the application of the ECL indicates a means of high-speed signal processing.

High Frequency Multipurpose SiC MOSFET Driver

This article describes a new multipurpose Silicone-Carbide (SiC) Metal Oxide Semiconductor Field Effect Transistor (MOSFET) driver, which was designed and manufactured for a high frequency operating SiC transistor as a semiconductor switching device of power converters. The design of the introduced driver enables to adjust the output voltage levels easily by choosing the integrated linear voltage stabilizers with suitable output parameters used for Printed Circuit Board (PCB) mounting. The voltage insulation of the proposed driver between the primary control side and the secondary output side is performed by MGJ6D12H24MC muRata Ps DC-DC converter with a declared dv/dt immunity 80 kV/1000 ms at 1.6 kV and by IX3180 IXYS High Speed gate driver optocouplers with a declared 10 kV/1000 ms minimum common mode rejection at 1.5 kV. The voltage insulation of these coupling elements is accompanied by safety gaps on the PCB. These insulation features enable the proposed driver to work on high frequencies as a high-side transistor of H-bridges as same as in other power converter topologies with a high frequency and high voltage stress of the insulation border. The proposed driver also provides the possibility of tripping the signal, when the short circuit of the controlled power transistor occurs.

Voltage Oscillation Suppression for the High-Frequency Bus in Modular-Multiactive-Bridge Converter

The electromagnetic interference issues, such as high-frequency oscillation (HFO) caused by the high dv/dt and parasitic elements, have been becoming a challenge in modern power electronics. Modular-multiactive-bridge (MMAB) converter, in which active bridge modules are linked with high-frequency transformers, is a typical power converter with a large number of switching semiconductor and magnetic devices. The mechanism of HFO in MMAB is studied by the analysis of the oscillation tank first. Then, from the perspective of the oscillation tank and the excitation source itself, two suppression strategies, including the passive voltage clamping method and active selected harmonic elimination general phase-shift modulation method, are proposed, respectively. Finally, the effectiveness of both methods is verified and compared by experimental results. The research results in this letter can be utilized in other topologies, such as dual active bridge, and may provide some inspiration to solve the similar HFO problem.

A cost‐effective and fault‐tolerant brushless direct current drive with open‐stator windings for low power electric vehicles

SummaryDual‐inverter‐driven open‐end winding brushless direct current motor (OEWBLDCM) drives are amenable for the implementation of some interesting fault‐tolerant features, which could find useful applications in low power electric vehicles (EVs). The power semiconductor switching devices in the dual‐inverter system are vulnerable to the development of open‐circuit faults (OCFs) and the short‐circuit faults (SCFs). This paper investigates the possibility of imparting complete fault‐tolerant capability to EVs, which employ OEWBLDC motors for propulsion. With the proposed dynamic post‐fault reconfiguration of the power circuit and the reconnection of the battery banks, it is possible to deliver the rated (i.e., 100%) post‐fault output power to the BLDC motor, despite the failure of a power semiconductor switching device (because of either an OCF or an SCF) in the dual‐inverter system. The feasibility evaluation of the proposed fault‐tolerant drive reveals that the aforementioned objectives are realizable at an affordable hike in the raw material cost of the propulsion system. Simulation studies and Experimental verification on a laboratory prototype validate the proposed fault‐tolerant OEWBLDCM drive.

Systematization of a Multilevel-Topology-Based Linear Amplifier Family for Noiseless DC–AC Power Conversion

Electrical power converters use semiconductor switching devices for larger loss reduction compared with non-switching power linear amplifier such as a class-B amplifier. However, it is well known that the switching operation produces harmonics and EMI noise, thus passive components are usually required for the suppression of these harmful sub-products. Use of recent fast power devices such as silicon carbide (SiC) and gallium nitride (GaN) devices produce larger dv/dt and di/dt than that of Si power devices and as a result above mentioned problem becomes more tangible. In this paper, the authors propose a concept of a family of multi-level linear amplifier (MLLA), which makes no switching power conversion possible. MLLA consist of series-connected switching devices and only one of them operates as a linear amplifier and the loss is much less than that of the class-B amplifier. The concept of the family is very useful when a proper MLLA topology might be selected for applications. In this paper, three kinds of MLLA—diode-clamped linear amplifier (DCLA), flying-capacitor linear amplifier (FCLA), and novel modular-cascaded linear amplifier (MCLA)—with four series connection of devices are investigated for the viewpoint of merits and demerits clarification and the efficiency over 82 % is demonstrated in the experiments.

Reliability Assessment of a Fault-Tolerant PV Multistring Inverter

In photovoltaic (PV) systems, the reliability of the system components, especially the power converters, is a major concern in obtaining cost effective solutions. In order to guarantee service continuity in the case of failure of elements of the PV converter, in particular, semiconductor switching devices, a solution is to design power converter with fault-tolerance capability. This can be realized by aggregating hardware redundancy on an existing converter, providing the possibility of replacement of faulty elements. This paper evaluates the reliability of a fault-tolerant power electronics converter for PV multistring application. The considered fault-tolerant design includes a single redundant switching leg, which is used in order to reconfigure the structure in case of a switch failure either on DC-AC or DC-DC stages. This paper details the reliability estimation of the considered PV multistring fault-tolerant converter. Furthermore, a comparison with a conventional structure without fault-tolerant capability is provided. The results show that the introduction of a single redundant leg allows for improving the converter mean time to failure by a factor of almost two and it reduces, by half, the power loss due to system-failure shutdowns in PV applications, while only increasing the converter cost by 2–3%.

Multifunction Control Strategy for Single-Phase AC/DC Power Conversion Systems With Voltage-Sensorless Power-Decoupling Function

In this article, a novel voltage-sensorless controller for the single-phase ac/dc power conversion systems with a self-adaptive power-decoupling function is proposed. Existing control strategies for achieving power decoupling usually require additional active switches or extra measurement circuits to a certain power-decoupling controller. By employing the proposed method, the decoupling voltage could be accurately evaluated with the fluctuations of the other measured state variables in the original converter, and the issues of instability and inaccuracy on power-decoupling control under transient conditions could be solved. Furthermore, the proposed control scheme involves a phase-shift modification to improve the power quality as well as achieve accurate power-decoupling reference, which could eliminate the harmonic influence on the original PFC circuit. Finally, a 1.2-kW single-phase PFC prototype using SiC-based semiconductor switching devices is tested to validate the proposed control scheme. The experimental results demonstrate that the power factor of 0.99 with total harmonic distortion around 3%, and a dc-link voltage with 5% ripple could be achieved with the proposed control strategy.