An Interleaved Boost Converter With Zero-Voltage Transition

This paper proposes a novel soft-switching interleaved boost converter composed of two shunted elementary boost conversion units and an auxiliary inductor. This converter is able to turn on both the active power switches at zero voltage to reduce their switching losses and evidently raise the conversion efficiency. Since the two parallel-operated elementary boost units are identical, operation analysis and design for the converter module becomes quite simple. A laboratory test circuit is built, and the circuit operation shows satisfactory agreement with the theoretical analysis. The experimental results show that this converter module performs very well with the output efficiency as high as 95%.     

ZVT-PWM AC-DC boost converter with ZCS auxiliary circuit

A low conduction loss, low-cost zero-voltage-transition-pulsewidth modulation (ZVT-PWM) boost converter with a zero current switching (ZCS) auxiliary circuit is developed to achieve high-conversion-efficiency operation. The unique locations of the resonant capacitor and inductor ensure that low switching stress and commutation losses are obtained in this converter. It is very suitable for high power-factor-correction pre-regulators     

A new soft-switched PWM boost converter with a lossless auxiliary circuit

A soft-switching scheme for the PWM boost converter is newly proposed to obtain the desirable features of both the conventional PWM boost and resonant converters such as ease of control, reduced switching losses and stresses, and low EMI. In order to achieve the soft-switching action, the proposed scheme employs an auxiliary circuit, which is added to the conventional boost converter and used to achieve soft-switching for both the main switch and the output diode while not incurring any additional losses due to the auxiliary circuit itself. The basic operations, in this paper, are discussed and design guidelines are presented. Through a 100?KHz, 60?W prototype, the usefulness of the proposed scheme is verified.     

Soft Switching Circuit for Interleaved Boost Converters

A zero-voltage switching-zero-current switching interleaved boost converter is proposed in this paper. An active circuit branch in parallel with the main switches is added and it is composed of an auxiliary switch and a snubber capacitor. By using this interleaved converter topology, zero current turn-on and zero voltage turn-off of the main switches can be achieved and the reverse-recovery loss of boost diode can be reduced. In addition, the auxiliary switches are zero-voltage transmission during the whole switching transition. A prototype of boost converter rated at 1.2kW has been built to confirm the effectiveness of the converter     

A New PWM-Controlled Quasi-Resonant Converter for a High Efficiency PDP Sustaining Power Module

A new pulsewidth modulation (PWM)-controlled quasi-resonant converter for a high-efficiency plasma display panel (PDP) sustaining power module is proposed in this paper. The load regulation of the proposed converter can be achieved by controlling the ripple of the resonant voltage across the primary resonant capacitor with a bidirectional auxiliary circuit, while the main switches are operating at a fixed duty ratio and fixed switching frequency. Hence, the waveforms of the currents can be expected to be optimized from the view-point of conduction loss. Furthermore, the proposed converter has good zero-voltage switching (ZVS) capability, simple control circuits, no hign-voltage ringing problem of rectifier diodes, no dc offset of the magnetizing current and low-voltage stresses of power switches. Thus, the proposed converter shows higher efficiency than that of a half-bridge LLC resonant converter under light load condition. Although it shows the lower efficiency at heavy load, because of the increased power loss in auxiliary circuit, it still shows the high efficiency around 94%. In this paper, operational principles, features of the proposed converter, and analysis and design considerations are presented. Experimental results demonstrate that the output voltage can be controlled well by the auxiliary circuit using the PWM method.      

A new, soft-switched, high-power-factor boost converter with IGBTs

A new soft-switching technique that improves performance of the high-power-factor boost rectifier by reducing switching losses is introduced. The losses are reduced by an active snubber which consists of an inductor, a capacitor, a rectifier, and an auxiliary switch. Since the boost switch turns off with zero current, this technique is well suited for implementations with insulated-gate bipolar transistors. The reverse-recovery-related losses of the rectifier are also reduced by the snubber inductor which is connected in series with the boost switch and the boost rectifier. In addition, the auxiliary switch operates with zero-voltage switching. A complete design procedure and extensive performance evaluation of the proposed active snubber using a 1.2 kW high-power-factor boost rectifier operating from a 90 V_rms-256 V_rms input are also presented     

A zero-voltage-switched PWM boost converter with an energyfeedforward auxiliary circuit

A zero-voltage-switched (ZVS) pulsewidth-modulated (PWM) boost converter with an energy feedforward auxiliary circuit is proposed in this paper. The auxiliary circuit, which is a resonant circuit consisting of a switch and passive components, ensures that the converter's main switch and boost diode operate with soft switching. This converter can function with PWM control because the auxiliary resonant circuit operates for a small fraction of the switching cycle. Since the auxiliary circuit is a resonant circuit, the auxiliary switch itself has both a soft turn on and turn off, resulting in reduced switching losses and electromagnetic interference (EMI). This is unlike other proposed ZVS boost converters with auxiliary circuits where the auxiliary switch has a hard turn off. Peak switch stresses are only slightly higher than those found in a conventional PWM boost converter because part of the energy that would otherwise circulate in the auxiliary circuit and drastically increase peak switch stresses is fed to the load. In this paper, the operation of the converter is explained and analyzed, design guidelines are given, and experimental results obtained from a prototype are presented. The proposed converter is found to be about 2%-3% more efficient than the conventional PWM boost converter     

Analysis, design, and implementation of an active clamp forward converter with synchronous rectifier

The system analysis, circuit design, and implementation of active clamp based forward converter with synchronous rectifier are presented in this paper. To release the energy stored in the leakage inductor and to minimize the spike voltage at the transformer primary side, active clamp circuit included one clamp switch and one clamp capacitor is adopted in the circuit. Based on the partial resonance with the output capacitor of switch and the leakage inductor of transformer, the main switch is turned on at zero voltage switching (ZVS). The clamp switch is also operated at ZVS operation based on the resonance of leakage inductor and clamp capacitor. The synchronous switches are used at the secondary side to further reduce the conduction losses. The experimental results based on the laboratory prototypes are presented to verify the circuit performance.     

辅助电路与主开关并联的单相全桥节能逆变器

为了改善逆变器的性能,提出了一种辅助电路与主开关并联的单相全桥节能逆变器.逆变器采用受限单极式正弦脉宽调制（Sinusoidal Pulse Width Modulation,SPWM）方法,在每个开关周期,只需要控制1个主开关和1个辅助开关的切换,辅助开关可以采用固定占空比控制,而且不需要设定谐振电流阈值来控制辅助开关.在每个开关周期的换流过程中,需要切换的主开关所并联的谐振电容的电压能变化到零,主开关能实现零电压软开通.辅助电路中无器件直接串联在直流母线上,可有效降低辅助电路通态损耗.分析了电路工作原理,实验结果表明主开关和辅助开关都实现了软切换.因此该拓扑能有效降低开关损耗和提高逆变器效率.     

具有低能耗辅助电路的三相谐振极逆变器

为优化三相逆变器的效率,提出了一种具有低能耗辅助电路的三相谐振极逆变器,其各相桥臂上分别设置了辅助电路.在辅助电路工作时,主开关可实现零电压软切换,辅助开关可实现零电流软切换,使开关损耗明显降低.此外,在辅助电路的谐振状态结束之后,谐振电感中的剩余电能将只通过1个二极管回馈给储能电容,降低了电能回馈时的辅助电路损耗,有...     

Optimized design of a fully soft-switched boost-converter suitable for power factor correction

A fully soft-switched boost-converter using a one auxiliary switch is presented here. It uses the minimum number of components in the auxiliary circuit with minimum current stress of the main switch. Since the resonant capacitor charges only through an inductor and a diode, the circuit conduction losses are minimized. The main and auxiliary insulated gate bipolar transistor (IGBT) switches share a common emitter connection, facilitating direct drive to them. Various operating modes of the converter are presented in detail and analysed. The choice of the resonating capacitor and inductor has been done through an optimization process based on the guiding equations working under different modes. In this optimization process, emphasis has been given on minimum voltage stress on the auxiliary switch for a wide duty cycle range of operation. Based on the design, the principle of operation has been verified with computer simulation. Experimental results from a laboratory prototype with active power factor correction confirms the operation of this converter.     

The novel resonant DC link three-level soft-switching inverter

ABSTRACT

In the paper, the novel topology of the resonant DC link three-level soft-switching inverter is proposed to reduce switching losses and improve the efficiency of three-level inverter at high switching frequency. Symmetrical auxiliary resonant circuits are set in the DC link of three-level hard-switching inverter. Moreover, the terminal voltage of the resonant capacitors between the DC buses periodically drops to zero via the resonance of auxiliary circuits. Furthermore, under such condition, the main switches of the three-level inverter would be operated, in order to achieve zero-voltage switching. Based on the equivalent circuits in different operating modes, the paper analyses the working process of the soft-switching inverter in detail. In addition, a 3 kW laboratory prototype of resonant DC link three-phase three-level soft-switching inverter is built. The experimental results show that the main switches and auxiliary switches of the inverter are operated under soft-switching conditions, and the efficiency is significantly improved compared with the three-level hard-switching inverter. Therefore, the proposed topology can effectively reduce switching losses and prove to be more practical in engineering.     

基于LPC2214的ZVZCS-PWM全桥变换控制器的研究

针对传统ZVZCS-PWMDC／DC全桥变换器在实现滞后桥臂开关管零电流开关过程中,存在着辅助谐振电路附加损耗较大,软开关实现方式复杂,功率开关管电压应力和电流应力高等缺点,介绍了一种新型次级箝位移相控制的ZVZCSPWMDC／DC全桥变换器。文中分析了该变换器实现软开关的原理,同时设计了变换器数字控制系统,控制器采用LPC2214型ARM芯片,并通过一台实验样机验证了这种软开关变换器相关理论的正确性以及该数字控制系统的可行性。     

A ZCS Current-Fed Full-Bridge PWM Converter With Self-Adaptable Soft-Switching Snubber Energy

A new soft-switched, current-driven full-bridge converter is presented. The structure utilizes a simple snubber formed by two unidirectional switches and a capacitor to realize soft-switching operation over a wide line and load range. All primary-side switches are operated with zero-current switching (ZCS) and the snubber switches are operated with zero-voltage switching. The energy used for soft-switching is self-adaptable. For a given input current, the snubber capacitor is charged to the minimum required energy for ZCS of the switches. Thus, less resonant energy is used and the conduction loss can be kept minimal. The cyclical switching operation and control of the converter will be discussed. By compromising the voltage stress on the switches and loss of duty cycle (i.e., the regulation range), an optimized design procedure of the circuit elements is derived. The input voltage range and load variation that ensure both output voltage regulation and soft switching are determined. By studying the small-signal characteristics of the entire system, a current-controlled feedback control circuit has been implemented with a DSP. The experimental results measured on a 5-kW, 530-V/15-kV prototype confirms the advantages of the proposed converter.      

推挽软开关光伏微型逆变器

为解决光伏微型逆变器对高效率、体积小、成本低的要求,研究了一种高效高增益升压推挽式隔离型电感—电容(LC)软开关串联谐振变流器。该变流器中功率开关管均能实现软开关。通过工作在升压模式下获得高输入输出增益可以有效的减少变压器匝比,提高转换效率。该变流器适用于光伏电池的能量升压转换场合。描述该变流器工作原理和电路特性,给出其拓扑结构,应用于一台试验样机光伏微型逆变器中,验证了该变流器的有效性和实用性。     

A composite soft-switching inverter configuration with unipolarpulsewidth modulation control

This paper presents a new composite soft-switching configuration for single-phase inverters where power bridge leg modules are used. The presented configuration consists of only one inductor and one capacitor as well as two low-power-rated switches/diodes for full-bridge circuits. It can realize snubber functions and/or resonant zero-current switching at any load current for switches in power inverters with unipolar sinusoid pulse width modulation control. The idea presented here is that soft-switching processes at turn-on and turn-off for each active switch in inverters can be different. The detailed circuit operational processes, simulation waveforms, and experimental results are included     

1-kW PFC converter with compound active-clamping

A PFC converter employing compound active clamping technique is proposed. It can effectively reduce the loss caused by diode reverse recovery. Both the main switch and the auxiliary switch can achieve soft-switching (ZVS) under certain conditions. The parasitic oscillation caused by the parasitic capacitance of the boost diode is eliminated. The voltage on the main switch, the auxiliary switch and the boost diode are clamped. The principle of operation and theoretical analysis are presented. The maximum voltage stress of switches and the soft-switching region with relation to the resonant inductor and resonant capacitance are investigated. A prototype of 1kW is built to test the proposed topology. The input voltage is from 90V/sub rms/ to 265V/sub rms/. The output voltage is 380V. The operation frequency is 100 kHz. The measured efficiency at full load with different input voltage is from 93.5% to 97.8%.     

节能型单相全桥谐振极逆变器

单相全桥逆变器处于硬开关状态时,随着开关频率的增大,开关损耗明显增大,影响逆变器效率的提高.为解决这一问题,提出了一种节能型单相全桥谐振极逆变器,在逆变器处于死区状态时,将要开通的主开关并联的谐振电容的电压能减小至零,主开关动作时能完成零电压软切换,双向辅助开关动作时能完成零电流软切换.讨论了电路的工作流程,实验结果表明主开关和辅助开关完成了软切换动作.该单相全桥软开关逆变器可以向高开关频率的场合推广应用.     

ZVT-PWM boost converter for unity power factor applications

A new single-phase ZVT-PWM boost converter with an active snubber is proposed to achieve unity power factor operations for a wide load range. The unique location of the resonant inductor and capacitor ensures that low switching stress and commutation losses are obtained in the converter. The proposed converter is suitable for high power factor correctors     

A Variable Frequency Phase-Shift Modulated Three-Level Resonant Single-Stage Power Factor Correction Converter

This paper presents a new single-stage three-level resonant power factor correction ac-dc converter suitable for high power applications (in the order of multiple kilowatts) with a universal input voltage range (90–265 Vrms). The proposed topology integrates the boost input power factor preregulator with a half-bridge three-level resonant dc-dc converter. The converter operation is controlled by means of a combination of phase-shift and variable frequency control. The phase-shift between the switch gate pulses is used to provide the required input current shaping and to regulate the dc-bus voltage to a set reference value for all loading conditions, whereas, variable frequency control is used to tightly regulate the output voltage. An auxiliary circuit is used in order to balance the voltage across the two dc-bus capacitors. Zero voltage switching (ZVS) is also achieved for a wide range of loading and input voltage by having a lagging resonant current in addition to the flowing of the boost inductor current through the body diodes of the upper pair of switches in the free wheeling mode. The resulting circuit, therefore, has high conversion efficiency and lower component stresses making it suitable for high power, wide input voltage range applications. The effectiveness of the proposed converter is verified by analysis, simulation, and experimental results.