Switch Voltage Stress Research Articles

Two-Switch Ultrahigh Step-Up DC–DC Converterer With Low Input Current Ripple and Low Switch Voltage Stress

Two-Switch Ultrahigh Step-Up DC–DC Converterer With Low Input Current Ripple and Low Switch Voltage Stress

Fully Soft Switched Bidirectional Buck–Boost Converter With Improved Voltage Conversion Ratio and Single Auxiliary Switch

In this paper, a fully soft-switched bidirectional buck/boost converter with improved voltage conversion ratio (VCR) and minimum semiconductor devices is proposed. An auxiliary circuit which employs only one active switch along with coupled inductors technique is utilized to increase VCR and provide soft switching condition for all semiconductor devices. Soft switching condition is provided at a wide power range while the leakage inductance energy of coupled inductors is absorbed in both power flow directions. The main switches are turned on at zero voltage-zero current switching and turn off at zero voltage switching, while the switches body diodes used as the converter diodes turn off at zero current switching which alleviates the diodes reverse recovery problem. Soft switching operation and low component count especially the active switches have contributed to realize a proper converter efficiency. Moreover, the converter has maintained continuous current at low voltage side, common ground between the high and low voltage sides and switches voltage stress similar to the basic bidirectional buck/boost topology. A converter prototype at 300W and 100kHz is implemented to confirm the converter theoretical operation and analysis.

A novel non-isolated step-down converter with low switch voltage stress

ABSTRACT This article is aimed at introducing a novel non-isolated step-down converter with superior advantages including reduced voltage stress on switching, enhanced efficiency as well as reduced number of required components. Improved distribution of voltage among several switches mitigates the stress exerted upon individual switches, thereby inflicting reduced voltage MOSFETS with smaller ON resistance. To show the superiority of the introduced converter over other converters of this kind through comparison, ON-OFF switching operations of two switches are performed under ZVS conditions, and as a result, a reduced switching loss is observed which is a proof for optimised efficiency. Finally, the design formula and simulations of the converter operating modes are discussed.

High Step-Up Quadratic Impedance Source DC-DC Converter Based on Coupled Inductor

In this paper, a new topology of quadratic impedance source DC-DC converters is proposed. In this topology, coupled inductor and auxiliary elements such as diodes and capacitors are used to increase the output voltage. The proposed converter can provide high voltage gain, low voltage sensitivity to duty cycle variations, continuous input current, the low voltage stress on the switch, diodes and capacitors, high efficiency, and common ground. First, the proposed converter is analyzed, and the components are designed. Moreover, loss analysis is given to prove its effectiveness. Then, the proposed converter is compared to other conventional converters to verify the claims. Finally, a 200W laboratory sample of the proposed converter is implemented to reconfirm the given theories. Based on the experimental results, the proposed converter’s efficiency is equal to 95.3%, and the switch voltage stress is reduced about 30% compared to the output voltage.

Wide voltage range and low current ripple bidirectional DC/DC converter

ABSTRACT Along with the prosperous growth of battery energy storage system being applied in renewable energy system, wide voltage range regulation and low current ripple bidirectional DC/DC converters attract much attention of researchers. Based on a basic boost–buck converter and voltage multiplying unit (VMU), this article proposes a two-stage DC/DC converter. The front stage is an input parallel output serial connected boost–buck converter and the back stage contains a dual-coupled inductors VMU. The storage inductors of the front stage aremagnetically coupled with those in back stage. Employing dual coupled inductors VMU can increase voltage gain while not increasing main switch voltage stress during step-up mode, which can widen the application scenarios. During step-down mode, a fully controlled method can obtain a greater step-down voltage ratio. Due to the interleaving control mode of the main switches, the current ripple of the battery side is lower when the converter works bidirectionally. The proposed converter has the advantages of widening voltage range regulation and lowering current ripple while avoiding extreme switch duty cycle. This article discusses theoretical step-up and step-down work mode of the proposed converter. Experimental results sampled from a 12 V/115 V prototype are presented to verify the analysis of the proposed converter.

Design Procedure for a High-Efficiency Class-E/F3 Power Amplifier

The switch voltage stress in a Class-E power amplifier (PA) is larger than that in any other switching PAs. A series resonant filter is added across the switch to filter out the third harmonic of the switch voltage and reduce the switch voltage stress. The new circuit is usually called a Class-E/F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> PA. The output power, the efficiency, and the component values of a Class-E/F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> PA can be <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sensiti</b> ve to the design of the harmonic filter. In this article, we perform a sensitivity analysis on Class-E/F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> PA and provide guideline to design a Class-E/F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> PA which is robust against variations in the harmonic filter components. We also provide new design equations to calculate the component values. To validate the proposed design guidelines and equations, a prototype circuit was designed and implemented. At <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DD</sub> = 4.5 V, the measured output power, the efficiency, and the switching frequency of the prototype PA were 0.96 W, 94.2%, and 800 kHz, respectively.

Transient response improvement of half‐bridge LLC resonant converter with full‐bridge rectifier for DC microgrid

AbstractLLC resonant converter has the features of low noise, high efficiency and power density, which is suitable to be integrated into DC microgrid. Due to severe stresses in the resonant tank, achieving fast and safe transient performance has been challenging for resonant converters. With less switch number and voltage stress, half‐bridge LLC resonant converter with full‐bridge rectifier (H‐F LLC resonant converter) are more suitable for high‐voltage application. To improve the transient response of the converter, this paper proposes a method based fixed center state trajectory for the converter to achieve soft start‐up. To reduce dynamic response time during start‐up, each step of fixed center state‐trajectory is designed optimally for the shortest path with symmetrical current limitation. In addition, the proposed method is also applicable to full‐bridge LLC converters. Moreover, according to the state‐plane analysis, load stepping‐up and stepping‐down transient state trajectories with the shortest path are carried out as well. To minimize the adverse effect of digital delay, fast load transient control based on 3D look‐up table is given based on FPGA‐EP3C25E144I7, which would also significantly reduce the computation requirement of the hardware controllers. The experimental results are verified on a 380V/12V LLC converter prototype at 130 kHz.

High gain coupled inductor SEPIC based boost inverter using extended SPWM

This research work designs a high gain coupled inductor SEPIC (CI-SEPIC) based boost inverter. This topology presents low switching voltage stress, high output DC and AC voltage and highly efficient system, which makes it suitable for renewable energy applications. A seventh order system is obtained through dynamic modelling of the CI-SEPIC converter for which PID controller is designed to track the reference value. The extended sine-wave pulse width modulation (ESPWM) has maintained the high gain without compromising the efficiency and ensured low voltage stress on the switching devices. Simulation and experimental results validated that CI-SEPIC based boost inverter with ESPWM achieved high dc gain of 15.98, boost factor of 25, exceptional dc-ac coupling with minimum possible capacitance of 3.3uF, decreased device stress by 33% and smaller size of the complete system.

Switched capacitor based 7-level and 9-level multilevel inverters with single DC source and reduced voltage stress

This paper proposes two different switched capacitor based Multilevel Inverter topologies having single dc voltage source. One of the proposed MLIs is a seven-level structure whereas the other circuit successfully generates a nine-level output voltage. The special features of the seven-level topology consist of reduced number of circuit elements, lower voltage stress on switches, and boosted output voltage. The nine-level MLI having unity gain also possess the reduced switch count along with lower value of switch voltage stress. Fundamental frequency based Nearest Level Control modulation and Level-Shifted Pulse Width Modulation have been used for generating the required voltage levels. Successful implementation of the proposed MLI circuits has been done with the help of a laboratory prototype and its results are presented and explained in the paper to show its practical suitability. Other type of analysis include loss analysis which has been done in PLECS software. From this analysis, the efficiency has been estimated. A comparative analysis of both the proposed structures has been carried out with some other similar topologies on different performance parameters. From the analysis and comparison, it is evident that the proposed MLIs are better than some of the existing topologies and can be used for industrial applications.

Ripple-Free Bidirectional DC–DC Converter With Wide ZVS Range for Battery Charging/Discharging System

A ripple-free bidirectional dc-dc converter (BDC) with wide soft-switching range is proposed for battery charging/discharging application in this paper. On battery side, the current ripple can maintain zero by two-phase interleaving technology in spite of the battery voltage and transfer power variation. Through series connection, high voltage conversion ratio and reduced voltage stresses of switches can be achieved effectively. The built-in transformer technology allows for a small magnetic component size, due to its inherent saturation avoidance. With the proposed control law, the control variables can be decoupled. The duty cycle is fixed by battery side voltage while the transfer power can be regulated monotonously by phase-shift angle. Theoretical derivation illustrates that soft switching can be obtained in all switches by adopting proper parameter design. Furthermore, comparative analysis shows the proposed converter is suitable for battery charging/discharging applications. The experimental verification proves the merits of the proposed converter by a 40-60V/400V 1 kW prototype.

A single phase modified Y-source inverter with high voltage gains and reduced switch stresses

Abstract This study is dedicated to develop a single-phase modified Y-source inverter (m-YSI) topology having a high boost factor and low switch voltage stress by adding a switch to the low voltage region. Thanks to this structure, continuous input current and wide control range are achieved regardless of winding factor. Since an external switch is used in the recommended modified Y-source inverter, the modulation index and duty ratio are controlled independently. Detailed analyses of the modified Y-source inverter were performed using Matlab/Simulink and its performance was compared with conventional Y-source inverters. Compared to selected conventional Y-source inverters, the proposed m-YSI has almost three times less voltage stress. A lower-cost topology has been obtained in which state-of-the-art control methods can be applied, thanks to a wide control range and circuit components with a low power ratio. This proposed model can be used as a double-stage micro-inverter in photovoltaic systems.

High Step-Up Boost-Cuk-Forward Converter with Reduced Switch Voltage Stress and Ripple-Free Input Current

High Step-Up Boost-Cuk-Forward Converter with Reduced Switch Voltage Stress and Ripple-Free Input Current

A Flat-Top Single-Ended Resonant Converter With Low Switch Voltage Stress

This paper proposes a flat-top single-ended resonant converter (SERC) for wireless charger with the merit of low switch voltage stress, by introducing a parallel LC network in series with the primary switch. A characteristics analysis of the proposed SERC is performed in time domain, obtaining the ZVS condition, power transfer capacity expression and the time requirement to achieve an ideal voltage cancelling. Due to the injected third harmonic, the voltage waveform of the switch can be shaped into a near trapezoid or a saddle shape. From the perspective of waveform superposition, we derive the conditions for the minimum switch voltage stress and the flat-top waveform of switch voltage. Finally, a 1900W prototype is built to verify the theoretical analysis. The experimental results show that the proposed converter achieved a flat-top switch voltage waveform and the voltage stress of 2.12 times the input voltage at full load, compared to that of 2.65 times the input voltage for the conventional one. Besides, the maximum efficiency is also increased to 93.33% from 92.32%.

Interleaved Boost-Integrated LC Series Resonant Converter With Frequency-Free Designed Transformer for Wide Voltage Range Applications

This paper presents a novel interleaved boost integrated LC series resonant converter with two output rectification modes, which are voltage-doubler rectifier mode and voltage-quadrupler rectifier mode with constant output voltage for wide input voltage range applications. Due to the symmetrical configuration of the rectifier, the voltage stress of switches and diodes on the secondary side are only half of the output voltage. With the proposed pulse frequency modulation, the maximum magnetic flux density <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B_m</i> of high frequency transformer is only related with the resonant frequency rather than the switching frequency. Hence, the transformer can be frequency-free designed. The zero-voltage-switching of the primary switches and zero-current-switching of the secondary switches and diodes are achieved, respectively. Moreover, the design procedure for some key parameters is presented. Finally, a 470 W prototype with a switching frequency range from 50 kHz to 140 kHz is built to verify the operation principles of the proposed converter and modulation.

Capacitor ripple reduction in T-type multilevel inverter operation for solar PV-application

Efficient and reliable power electronic converters are desired to integrate renewable energy sources into households or the grid. Multilevel inverters for their benefits are being explored for low-power applications. In this work, recently introduced 9-level T-Type switched-capacitor multilevel inverters are explored for 11-level operation, increasing their reliability in high-temperature conditions. The operation makes it capable of generating more voltage levels than the prior technology and diminishes capacitor inrush currents. Eventually, in 9-level operation, the undesired continuous high inrush current peaks are inevitable, which heat the capacitors due to electrolytic series resistance (ESR). This leads to early electrolyte evaporation and thus results in capacitance variation and an increase of ESR with time. In order to suppress the capacitor inrush currents, additional inductance of small value in the charging circuit is sought to mitigate these currents, but that leads to increased losses and increased switch ringing effect. In this work, the modulation of the inverter is performed to produce 11-levels at the inverter output. Inverter redundant states are so employed that the capacitors are always charged and discharged through the load. This results in reduction of inrush current peaks by approximately 20 times, thereby increasing the reliability and life of the inverter and making them more suitable for Solar PV applications in harsh weather conditions. This structure and modulation strategy also achieves lower switch voltage and current stresses. The improved topology and the modulation strategy are validated on the controller hardware-in-the-loop (CHIL) setup and PLECS environments. Further, the topologies are experimentally validated on a laboratory prototype.

A new symmetric modular eleven‐level inverter using single and double source unit for low voltage applications with reduced number of switches

AbstractThis study proposes a modular multilevel inverter for low‐voltage applications, including ac‐coupled renewables and energy storage systems. These inverters require many switches and gate drivers in their structures, which complicates the control system, reduces efficiency, and increases costs. This study introduces a new modular multilevel inverter that can produce five levels of positive voltage using only six power switches and five DC voltage sources. The basic unit is composed of a single‐ and double‐source (SDS) unit. SDS reduces the number of power electronic components, such as the insulated gate bipolar transistors, freewheeling diodes, gate driver circuits, dc voltage sources, and blocking voltage by switches. The proposed topology can boost the number of output voltage levels and decrease the number of switching devices and voltage stress using some combinations of basic submodules. The performance of the proposed 11‐level single‐phase inverter is compared with that of the conventional structures and recent symmetric topologies considering the number of switches, cost, and efficiency. The waveform quality and both the voltage and current harmonic characteristics were determined in accordance with IEEE 519–2014. Finally, an 11‐level prototype was constructed to validate the theoretical analysis, feasibility, and effectiveness of the proposed inverter.

A Novel Pull-Up Active-Clamping Wireless Charging Circuit with Low Cost and Voltage Stress

The traditional single-switch circuit has the advantages of fewer components, no shoot-through problems, and suitability for high-frequency wireless charging applications. However, because of the high voltage stress of the switch, the bulky inductor, and the narrow soft-switching range, its power and applications have some limitations. To relieve this problem, this paper proposes a pull-up active-clamping circuit, which not only offers a low component count with no bulky inductors, but also greatly reduces the switch voltage stress. In addition, a wide range of soft switching can be achieved by designing a primary-side compensation capacitor. A detailed parametric design method is given and compared with existing circuits from the aspects of switch voltage stress, component count, efficiency, cost, and so on. Finally, a 1 MHz, 180 W active-clamping wireless charging system is built to verify the proposed circuit and design method.

A High Step-Up Integrated Buck-Boost-Zeta Converter Using Three-Winding Coupled Inductor With Current Sharing Considered

This paper proposes a high-gain Buck-Boost-Zeta converter with three-winding coupled inductor, which is generated by differentially connecting the Buck-Boost converter and the Zeta converter and integrating the coupled inductor multiplier cell. An active switched-inductor is obtained at the input side by differential connection, which is used as the primary winding of the three-winding coupled inductor, and the multiplier cell is composed of the secondary winding and diode-capacitor. The diode-capacitor circuit in the topology is multiplexed as a passive clamp branch to absorb the leakage energy and the ZCS turn-on of the switches is achieved. Therefore, the proposed converter achieves higher voltage gain and lower switch voltage stress. At the same time, the proposed converter retains the continuous output current characteristic of the Zeta converter. The operation principles and performances of the proposed converter are analyzed in detail. Meanwhile, the imbalance currents of the primary windings caused by the leakage inductance error is analyzed and the coupled inductor current sharing method is given, which effectively alleviates the current pulsation of the primary winding. A 400W experimental prototype is built to verify the theoretical analysis.

Design analysis and control of step‐up converter with reduced switch stress

SummaryIn light of the increasing share of renewable energy sources (RES) in electricity generation, the research community is directing their attention toward developing highly efficient DC‐DC high‐gain step‐up converters. These converters are designed to exhibit reduced voltage stress on the switching devices (semiconductors). This paper presents a comprehensive study of a switch voltage stress‐reduced step‐up converter that offers a range of additional features, including the availability of a common ground point, continuous input current, simple two‐mode continuous conduction mode (CCM) operation, wide duty cycle range, and quadratic boosting factor. To achieve the aforementioned features, the converter utilizes two switches with the same operating modes, eliminating the need for complex switching circuitry. Operational modes, steady‐state analysis, and design considerations have been presented in detail. Comparative analysis indicates that the voltage conversion ratio per number of devices in the proposed topology is significantly higher than that of similar topologies. In addition, the voltage stress of switches is considerably less than the topologies addressed in the literature. The study further includes detailed mathematical and experimental analyses, small signal analysis, and hardware implementation to support the theoretical findings. The converter's efficiency has been thoroughly analyzed along with thermal analysis to ensure its reliability.

Impact of Space Vector Selection and Input Displacement Angle on Switch Voltage Stress of Current Source Rectifier

Three-phase current source rectifier (CSR) is concerned due to its flexible output voltage regulation, high reliability and fast dynamic response. Excessive voltage stress on the switch will increase the cost of the rectifier and reduce the reliability of the system. Therefore, it is essential to optimize the voltage stress of the switch. In this letter, the voltage stress of switch caused by each current vector in space vector modulation (SVM) is analyzed. Then, the vectors with low voltage stress are selected for combination to reduce the voltage stress of the switch without changing the topology. In addition, the vectors are re-optimized considering the effects of displacement angle. The re-optimized SVM can reduce the voltage stress by up to 13% under the leading or lagging power factor operation. Furthermore, the dc-link current ripple and modulation index range of different modulation methods are compared, and the effectiveness of the proposed modulation schemes are verified by experiments.