Semiconductor Switches Research Articles

A comprehensive review on various non-isolated power converter topologies for a light-emitting diode driver

Light-emitting diode (LED) lighting applications aided by an electronic power control have become very attractive in the recent years. For LED lighting applications, it is essential to design a converter with single/multi-output for handling multiple loads. As the LED load is more sensitive to the change in input/converter parameters, it is necessary to regulate the current concerning the design specifications. In this paper, several LED topologies are reviewed with a focus on power density, single/multi-load operation, size, and reliability. Several converter topologies are reviewed and compared in terms of power rating, number of semiconductor switches, isolation, and efficiency. Various modulation techniques used for dimming control are described in brief. The salient features of each converter topology are discussed with the power rating and application for which the topology can be preferred. So, the selection of the power factor correction (PFC) and low source side harmonics converter topology is presented. This paper will be helpful to the researchers who are working on the development of LED drivers.

Soft‐switched full‐bridge converter for LED lighting applications with reduced switch current

SummaryLighting systems using light‐emitting diode (LED) have drawn significant attention across the world. This is due to their promising features such as high energy efficiency, reduced greenhouse gas emission, and eco‐friendly nature. However, these systems require constant current regulators to provide constant illumination. This article proposes a soft‐switched full‐bridge LED driver circuit for dc‐grid applications with dimming control operation. The circuit consists of a soft‐switched full‐bridge converter to power different LED lamps with reduced device count from dc‐grid voltage. The semiconductor switches of the full‐bridge converter conduct a small current during on time due to interleaved inductor and equal current sharing of lamp‐2 and lamp‐3. This feature reduces the conduction losses. In addition, the proposed converter yields less component count per lamp, dimming operation through on–off control and zero voltage switching, which results in low switching losses. The detailed steady‐state analysis of the proposed converter for dc‐grid applications with dimming control operation is presented in this work. The performance of the proposed converter is compared with other similar topologies available in the recent literature. Numerical simulations and real‐time experimental validations are conducted to evaluate the steady‐state performance of the proposed converter topology for LED applications, driving multiple lamp loads from dc‐grid. It has been established that the efficiency of the proposed full‐bridge converter is 97.52% at the rated power.

Heteroepitaxial Growth of an Ultrathin β-Ga2O3 Film on a Sapphire Substrate Using Mist CVD with Fluid Flow Modeling.

β-Gallium oxide (Ga2O3) has received intensive attention in the scientific community as a significant high-power switching semiconductor material because of its remarkable intrinsic physical characteristics and growth stability. This work reports the heteroepitaxial growth of the β-Ga2O3 ultrathin film on a sapphire substrate via mist chemical vapor deposition (CVD). This study used a simple solution-processed and nonvacuum mist CVD method to grow a heteroepitaxial β-Ga2O3 thin film at 700 °C using a Ga precursor and carrier gases such as argon and oxygen. Various characterization techniques were used to determine the properties of the thin film. Additionally, a computational study was performed to study the temperature distribution and different mist velocity profiles of the finite element mist CVD model. This simulation study is essential for investigating low to high mist velocities over the substrate and applying low velocity to carry out experimental work. XRD and AFM results show that the β-Ga2O3 thin film is grown on a sapphire substrate of polycrystalline nature with a smooth surface. HR-TEM measurement and UV-visible transmission spectrometry demonstrated heteroepitaxial β-Ga2O3 in an ultrathin film with a band gap of 4.8 eV.

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 Tri-Port Current-Source Soft-Switching Medium-Voltage String Inverter for Large-Scale Solar-Plus-Storage Farms

This article presents a tri-port current-source soft-switching medium-voltage string inverter (TMVSI) to reduce the Levelized cost of energy (LCOE) of large-scale solar-plus-storage (SPS) farms. Throughout this work, the topology, operating principle, circuit simulation, control, and hardware design of the TMVSI are introduced. In addition, three key challenges compromising the performance of the TMVSI are addressed in this article. First, a new feed-forward compensation for model predictive control of the TMVSI is proposed to compensate for sampling and computational delay and high dc-link ripple with low computational cost and high scalability. Second, the use of laminated permanent magnets is proposed to reduce the losses of the MV medium-frequency transformer (MFT) in the TMVSI while increasing its saturation current. Finally, an improved U-shape winding pattern is proposed to decrease the leakage inductance of the MV MFT and reduce the voltage stress across semiconductor switches without adding cost or complexity. The effectiveness of the TMVSI is validated by experiments at up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$20\,\mathrm{kW/500\,V}$</tex-math></inline-formula> in different test cases with custom-built prototypes. The contributions of this work make the TMVSI a viable solution to SPS farms and unleash its potential for LCOE reduction.

Design and Analysis of Dual Input Z-Source Matrix Converter

Abstract: Series Z-Source community, connecting in helping vast o preferred concept of Z-supply dc hyperlink, changed into initially projected for boosting the output voltage of strength digital inverters. Throughout this paper, that idea is prolonged on a three-section oblique matrix converter. The converter relies upon at the ultra-sparse matrix topology characterised via way of means of the minimal vary of semiconductor switches. The collection Z-supply community is positioned among the three-transfer enter rectifier level and moreover the six-transfer output electric converter level, in both the wonderful or terrible rail. A short shoot-via nation produces the voltage raise. Associate in Nursing optimum pulse breadth modulation approach is advanced for better boosting capability of the converter and decrease of transfer losses. A evaluation is made among the matrix converters mistreatment collection and standard cascade Zsource networks. The inpouring modern-day and Z-supply capacitor’s voltage are decreased in the collection Z-supply matrix converter.

An energy efficient modified passive power filter for power quality enhancement in electric drives

In most industrial applications, AC drives are used. These drives require power electronic modules to convert AC to DC and also DC to AC. The power modules used for power conversion consist of power semiconductor switches. There is distortion in the voltage and current obtained from the power modules due to non-linear behaviors of semiconductor switches. To reduce the distortion in the input current, inductors are used along with the line impedance. A high value of inductance is required to maintain the percentage of THD within limits set by the latest standards. Along with the increased size and cost, it also reduces the power factor and output DC voltage at higher loads. The use of a passive power filter (PPF) is the conventional method followed for the reduction of percentage THD and promotion of the power factor. PPFs comprise passive elements such as the resistor, inductor, and capacitor. These passive elements are connected at the point of common coupling (PCC) in shunt to compensate for the harmonics present in the input current. In this study, a modified multi-tuned passive filter is considered to reduce the source current harmonics. A bridge rectifier with resistive load, three-phase induction motor drive, and linear resistive–inductive load is connected at the point of common coupling to analyze the harmonics present in the source current, and also unbalanced created in one phase. To achieve proper selection of the resistance value for the passive filter, the class topper optimization technique is used. To validate the simulation results obtained for the multi-tuned passive filter, the hardware is implemented with a three-phase AC induction motor drive load, in which the speed of the motor is controlled with voltage by a frequency control algorithm using an FPGA controller; The 50% THD is reduced by using the fifth-order filter alone, 75% by combining the fifth- and seventh-order filters, 85% by combining the 5th-, 7th-, 11th-, 13th-, and higher-order filters, and 90% for varying loads. For single-phase AC induction motor load, THD % is reduced to 4%, and for three-phase AC induction motor drive, THD % is reduced to 10% with the same value of the filter.

An efficient switched inductor–capacitor‐based novel non‐isolated high gain SEPIC for solar energy applications

AbstractThe solar photovoltaic (PV) sources have low voltage output and hence cannot be used directly in micro‐grid applications. Therefore, to boost the low voltage output, a novel high gain single‐ended primary inductor converter (SEPIC) is proposed in this manuscript. The proposed high gain SEPIC (HGS) has an advantage of obtaining high voltage gain at a low duty ratio and continuous input current, which makes it viable for PV applications. The proposed converter offers simple control, and the high gain is obtained without the use of any transformer or coupled inductor so the semiconductor switch will not experience a voltage overshoot during the turn‐off operation. Hence, the conduction losses of the converter switch are reduced, and the performance of the converter is enhanced. Additionally, this manuscript also investigates the effectiveness of the proposed HGS in integration with the PV array. An extensive performance evaluation of the proposed HGS is investigated and compared with different SEPIC topologies in irradiance change conditions. Experimental implementation of the proposed HGS confirms the theoretical analysis and verifies the performance. Also, the real time (RT) analysis of the proposed HGS with PV array is conducted to show the validation of high gain operation for the PV application.

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.

A Review of Open-Circuit Switch Fault Diagnostic Methods for Neutral Point Clamped Inverter

Due to numerous advantages, a neutral point clamped (NPC) inverter is a preferred choice for high-power applications and renewable technology. The reliability of the NPC inverter is a major concerning factor during the assessment of system performance as power semiconductor switches are vulnerable to abnormal conditions. Open-circuit (OC) switch faults are not as dangerous as short circuit (SC) faults but eventually have enough potential to cause cascaded failure to other components in the system and thus need to be supervised carefully. The OC faults result in a distortion of voltage and current signals in the NPC converter. Based on these signals, over the past few years, many efforts have been made to identify and localize the OC switch fault to the switch level in the NPC topology. In this paper, a review of different OC switch fault diagnostic methods is provided. Starting from the NPC inverter operation under healthy and faulty conditions, the various possible and unavailable switching states along with the deviation in pole voltage under different switch fault conditions is discussed. Then, based on the approach used for system-based fault detection, the OC fault detection methods are classified. The various OC methods are further discussed on the basis of signal, i.e., current, voltage or a combination of both signals used as a signature for fault detection. Emphasis is given to the principle involved, diagnostic variables utilized, the implementation approach and the diagnostic time required. Finally, the approaches are tabulated so as to provide a quick reference for NPC fault diagnostics.

Low Specific Contact Resistivity of 10−3Ω·cm2 for Ti/Al/Ni/Au Multilayer Metals on SI-GaN:Fe Substrate

For the application of third-generation compound semiconductors based on high-voltage, high-power, and high-frequency devices, particularly in photoconductive semiconductor switches (PCSSs), the ohmic contact preparation technology on semi-insulating substrates is crucial. However, iron-doped semi-insulating gallium nitride (SI-GaN:Fe) with low carrier concentration and high bulk resistivity has a very difficult time achieving good ohmic contact characteristics. Here, we have demonstrated preliminary results on an interesting class of good ohmic contact of Ti/Al/Ni/Au on Ga-face of SI-GaN:Fe. The results indicated that the Ti and Al thickness ratio is a critical parameter when determining the optimum annealing temperature and time for ohmic contact. With alloyed Ti/Al/Ni/Au stacks of 20 nm/120 nm/55 nm/45 nm on SI-GaN:Fe after annealing at 850 °C for 35 s in N2 atmosphere, a low specific contact resistivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-3}\,\,\Omega \cdot $ </tex-math></inline-formula> cm2 is achieved. At a future date, such excellent ohmic contact characteristics can be applied to the SI-GaN:Fe-based high-power PCSS.

A Novel 17-Level Reduced Component Single DC Switched-Capacitor-Based Inverter With Reduced Input Spike Current

Multilevel inverters (MLIs) have become common and resourceful as a result of the fast advancement of technology in the areas of high-voltage and high-power applications, among other things. Recently, MLIs have received a great deal of attention recently, due to the growing need to harness environmentally friendly energy. With reduced power electronics switches, diodes, and a voltage boost gain factor of 8, this article presents a single-phase 17-level switching capacitor inverter design. The proposed inverter uses single dc voltage source, two diodes, 14 power electronics switches, and three capacitors. The different mode of operation of topology is explained in detail, including their self-voltage balancing technique. Additionally, an inductor is used in the capacitor charging loop to avoid current spikes caused by the input dc source while charging the capacitor quickly, thereby increasing capacitor life expectancy significantly. Compared to previously the proposed single-input MLIs, the proposed inverter has a lower semiconductor switch count and a lower cost function value that are its distinguished feature. The performance of the topology is verified by MATLAB/Simulink, and furthermore, a laboratory prototype is utilized, which confirms the feasibility of the proposed topology.

Properties of Switching Transient in the Semi-Insulating GaAs Photoconductive Semiconductor Switch With Opposed Contacts

The properties of switching transient in the gallium arsenide photoconductive semiconductor switch (GaAs PCSS) are significant for improving the device lifetime. In this article, the properties of switching transient in the opposed-contact semi-insulating (SI) GaAs PCSS, including the physical process of the ultrafast switching, the characteristics of delayed breakdown, and the current density distribution, are studied, based on an effective 2-D, time-dependent numerical model. The numerical results demonstrate that there exists a positive feedback loop between the increase of the carrier density and the formation and evolution of the avalanche domains, which achieves the ultrafast switching of the opposed-contact SI-GaAs PCSS. The higher bias voltage and triggering optical intensity can promote the earlier formation of the avalanche domains and accelerate the evolution of the domains, leading to a shorter delay time and switching time. The triggering positions determine the distribution of the avalanche domains in the opposed structure, affecting the delay time, among which the cathode triggering leads to the shortest delay time. Current crowding in the opposed structure mainly occurs in the vicinity of the contacts, which first damages the edges of the contacts and makes the areas near the contacts present different failure characteristics. Our analysis indicates that anode triggering is effective for suppressing the current crowding to improve the lifetime of the opposed-contact PCSS.

Fault-Tolerant Operation of Bidirectional ZSI-Fed Induction Motor Drive for Vehicular Applications

This paper presents an efficient and fast fault-tolerant control scheme for a bidirectional Z-source inverter (BiZSI)-fed induction-motor drive system for vehicular applications. The proposed strategy aims for the fault detection, localization and diagnosis of the proposed system during switch failures in the inverter module. Generally, power–semiconductor switch failures in inverter modules occur due to open- and short-circuit faults. An efficient modulation scheme is proposed and design specifications are thoroughly derived to obtain high voltage gains across the BiZSI network. A suitably fast detection and diagnosis scheme to isolate the faulty leg and resume the normal operation is discussed in this paper. The control scheme is provided such that the faulty leg is isolated and the motor phase is fed from a redundant leg to resume the operation. A feasible localization algorithm based on experimentally derived values and switching vectors is implemented. In addition, a fast fault diagnosis method based on current estimation and motor speed variation is designed and implemented. Moreover, the most important advantages of the proposed strategy include lower hardware requirements and less harmonic distortion in the output currents. Finally, the simulation and experimental results are presented to validate the feasibility of the theoretical analysis. An extensive performance evaluation of the proposed system with fault ride-through capabilities is performed to prove its suitability for vehicular applications. To validate its merits, the proposed strategy is compared with similar fault-tolerant schemes currently used in the industry.

Molecular-Shape-Controlled Binary to Ternary Resistive Random-Access Memory Switching of N-Containing Heteroaromatic Semiconductors.

In organic resistive random-access memory (ReRAM) devices, deeply understanding how to control the performance of π-conjugated semiconductors through molecular-shape-engineering is important and highly desirable. Herein, we design a family of N-containing heteroaromatic semiconductors with molecular shapes moving from mono-branched 1Q to di-branched 2Q and tri-branched 3Q. We find that this molecular-shape engineering can induce reliable binary to ternary ReRAM switching, affording a highly enhanced device yield that satisfies the practical requirement. The density functional theory calculation and experimental evidence suggest that the increased multiple paired electroactive nitrogen sites from mono-branched 1Q to tri-branched 3Q are responsible for the multilevel resistance switching, offering stable bidentate coordination with the active metal atoms. This study sheds light on the prospect of N-containing heteroaromatic semiconductors for promising ultrahigh-density data-storage ReRAM application.

Density-Dependent Effects on Pulse Compression in GaN Photodetectors Probed by Monte Carlo Studies

With increases in the demand for faster electronic switching, requirements for higher operating voltages and currents, and the need to perform under harsh environments while operating at even higher frequencies, the research focus in photoconductive semiconductor switch (PCSS) technology has shifted to wide bandgap semiconductors. Here, we examine the possibility of pulse compression in carbon-doped PCSS devices based on the negative differential mobility concept for faster operation. Monte Carlo simulations are used to build in and model various effects on electron transport including degeneracy, charge polarization, and scattering within a three-valley model fitted to bandstructure calculations. The focus is on exploring the density dependence of pulse compression. Thresholds for the biasing fields naturally emerge. Predictive analysis of the output full-width half-maximum (FWHM) current waveforms, as well as the dynamics of the internal charge cloud behavior, and occupancy of the various valleys within GaN are all obtained. Our results show that an increase in carrier density can increase pulse compression and create pulse-widths that are smaller than the FWHM of the input optical excitation. This bodes well for enhanced repetition rates. Variations produced by moving the laser spot along the GaN PCSS length are also examined. Though data for GaN are not yet available, the trends compare well qualitatively with previous reports for GaAs.

Evaluation of Pulsed Spark Discharge for Triggering GaAs Photoconductive Semiconductor Switches

In this study, a 3 mm gap GaAs photoconductive semiconductor switch (GaAs PCSS) was triggered by pulsed spark discharge. The typical linear mode of GaAs PCSS was fulfilled at a low bias voltage. The on-state current waveform was similar to that of an optical pulse. The “nonlinear mode” was demonstrated at a bias voltage of 4 kV; concurrently, the peak current and the carriers’ multiplication rate were 33 A and 179, respectively. This study indicates that pulsed spark discharge is a promising candidate light source for the direct triggering of GaAs PCSSs.

Study of a Si-based light initiated multi-gate semiconductor switch for high temperatures

Light initiated multi-gate semiconductor switch (LIMS) is a kind of power electronic device which has many differences from traditional thyristor triggered by electric pulse. LIMS is triggered by laser, the turn-on time is smaller, and the anti-electromagnetic interferences is strong. The opening mode of LIMS is obviously different to traditional thyristor. After the laser into the gate area, a large number of electrons and holes will appear in P-base region, holes gather in the area of P-base in PN junction J2, and electrons gather in N-drift region around the PN junction J2. PN junction J2 will open first, then PN junction J3 opens. The delay time of the NPN and PNP thyristors is close to zero when the laser pulse is narrow and the peak power is high, so the turn-on velocity is fast. To optimize the characteristics of the LIMS at high temperatures, we propose a new structure of the LIMS with the optimization of the n+ layer, circular light gate, and the new-style edge termination. The diameter of the LIMS is 23 mm. The experiment results show that the leakage current of the proposed LIMS has been decreased from more than 1 mA to 500 μA at 125 °C, the output current of the LIMS is 10.2 kA with a voltage of 4 kV at 85 °C, and the output current of the LIMS is 12.1 kA with a voltage of 4 kV at − 55 °C. Additionally, di/dt is larger than 30 kA/μs.

A Study on Semiconductor Switch Characteristics for a High Repetitive Fast Rising Solid-State Modulator

In this study, semiconductor switches are analyzed, compared, and selected for solid-state pulsed power modulators with a high repetitive fast rise time. Characteristics of discharge switches are critical in the design of pulsed power modulators with a fast rise time of several tens of nanoseconds. Five types of switches, including insulated gate bipolar transistor (IGBT) and silicon carbide metal–oxide–semiconductor field-effect transistor (SiC-MOSFET), were analyzed to select a discharge switch in addition to a comparison considering their rise time, arc reliability, and cost. A test circuit was designed and used to compare the rise time of semiconductor switches. Finally, a 1200-V/40-A IGBT was selected as the best performing discharge switch. The rise time and cost of the selected IGBT were up to 30% slower than and 1/6 those of the comparison SiC-MOSFET, respectively. The selected IGBT was employed in a high-voltage pulsed power modulator with specifications of 10 kV, 80 A, a maximum repetition rate of 50 kHz, and a minimum pulsewidth of 100 ns. The modulator exhibited a rise time of 18 ns or less and an operating repetition rate of 50 kHz. Finally, the fast rise time of the selected switch and its arc reliability was verified.

A Fault-Tolerant Power Converter With Multi-Switch Fault Diagnosis and Repair Capability for 4-Phase 8/6 SRM Drives

In this article, a modular fault-tolerant power converter for 8/6 four-phase switched reluctance motor (SRM) drives is presented. The proposed converter can work for both open-circuit (OC) and short-circuit (SC) fault conditions in the power semiconductor switches. A semiconductor switch module and a relay circuit are used for achieving the fault tolerance feature. The proposed converter is modular and provides independent fault-tolerant control for all phases. It also uses a minimum number of switches when compared with other fault-tolerant converter topologies. The proposed converter is tested for a fault in single as well as multiple phases using MATLAB/Simulink software and is validated experimentally on a 0.6 hp 8/6 SRM using an FPGA-based hardware setup developed in the laboratory. Detailed results are presented and compared with existing fault-tolerant converter topologies. A fault repair time of 2 ms has been achieved for both open and SC faults.