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 three-phase soft-transition inverter with a novel controlstrategy for zero-current and near zero-voltage switching

This paper proposes a new soft-transition control strategy for a three-phase zero-current-transition (ZCT) inverter circuit. Each phase leg of the inverter circuit consists of an LC resonant tank, two main switches, and two auxiliary switches. The proposed strategy is realized by planning the switching patterns and timings of these four switches based on the load current information. It enables all the main switches and auxiliary switches to be turned on and turned off under zero-current conditions, and achieves a near zero-voltage turn-on for the main switches. Compared with existing ZCT strategies, the diode reverse recovery current and switching turn-on loss are substantially reduced, the current and thermal stresses in the auxiliary devices are evenly distributed over every switching cycle, and the resonant capacitor voltage stress is reduced from twice the DC bus voltage to 1.3-1.4 times the DC bus voltage. The proposed strategy is also suitable for three-phase power-factor-correction (PFC) rectifier applications. The operation principles, including a detailed analyst based on the state-plane technique, and a design rule are described in this paper. The circuit operation is first verified by a computer simulation, and is then tested with a 50-kW three-phase inverter to the full power level together with a three-phase induction motor in a closed-loop speed/torque control. Significant reductions in switching losses and voltage/current stresses over existing techniques have been experimentally demonstrated     

Zero-Voltage Transition Current-Fed Full-Bridge PWM Converter

In this paper, a new zero-voltage transition current-fed full-bridge converter with a simple auxiliary circuit is introduced for high step-up applications. In this converter, for the main switches, zero-voltage switching condition is achieved at wide load range. Furthermore, all semiconductor devices of the employed simple auxiliary circuit are fully soft switched. The proposed converter is analyzed and a prototype is implemented. The experimental results presented confirm the validity of the theoretical analysis. Finally, the proposed auxiliary circuit is applied to other current-fed topologies such as current-fed push-pull and half-bridge converters to provide soft switching.     

电流型零电压开关节能整流器

为解决电流型脉冲宽度调制（Pulse Width Modulation,PWM）整流器在高开关频率下硬切换时的开关损耗问题,提出了一种电流型零电压开关节能整流器,其辅助谐振电路位于直流环节,且与直流母线并联,只有1个辅助开关.在换流过程中,主开关能实现零电压切换,辅助开关能实现零电流切换,而且当整流器采用多电平PWM控制策略时,辅助电路在每个开关周期只需工作1次.分析了谐振换流过程,仿真结果表明特征仿真波形符合理论分析,开关器件切换时处于软开关状态,整流器能平稳运行.该电流型零电压开关节能整流器可以在高开关频率和大功率的应用场合实现高效率运行.     

改进软开关Buck ZCT-PWM开关电路设计及其Pspice仿真

介绍了典型的零电流转换ZCT（Zero Current Transition）PWM直流变换器的基本工作原理,分析了其存在的主开关电流应力大和辅开关硬关断的问题,提出了一种改进型开关电路。对其拓扑结构和工作原理进行了详细分析,设计了电路参数,并对其进行了Pspice仿真。结果证明此改进能够使辅助开关近似零电流关断,提高了变换器的性能。     

Active-clamp ZVS converter with step-up voltage conversion ratio

This article presents the circuit implementation and design considerations of a zero voltage switching (ZVS) converter with voltage step-up for battery-based applications. An active-clamp circuit including one auxiliary switch and one clamp capacitor is connected in parallel with the main switch to allow resonant behaviour by the output capacitances of switches and transformer leakage inductance during the transition interval. Thus, the ZVS turn-on of switches can be achieved. The switching losses and thermal stresses of the semiconductors are reduced. The circuit configuration, operation principle and design considerations of the converter are discussed in detail. Finally, experiments conducted on a laboratory prototype rated at 200 W are provided to verify the theoretical analysis and the effectiveness of the proposed converter.     

单相全桥三电平节能逆变器

随着开关频率的提高,单相全桥逆变器处于硬开关切换时的开关损耗也会明显增大,将导致逆变器处于低效率运行.为解决这一问题,提出了一种单相全桥三电平节能逆变器.通过设置辅助换流电路,利用谐振使主开关并联的电容的电压下降到零,主开关可实现零电压切换,而且在换流过程中,两组双向辅助开关可分别实现零电压切换和零电流切换.分析了电路的工作状态,实验结果表明主开关和辅助开关都能实现软切换.因此该单相全桥三电平逆变器可实现高效率运行.     

节能型谐振直流环节逆变器

为改善逆变器的运行效率,提出了一种节能型三相谐振直流环节软开关逆变电路,在直流环节增设了辅助电路.当主开关需要切换时,提前使辅助电路进入谐振状态,将直流环节电压变化到零,保证主开关完成零电压软切换,并且辅助开关也能完成软切换.通过控制辅助开关切换的间隔时间来调节直流环节电压保持为零的时间,使逆变器能根据需要来调整脉宽调制策略.详细说明了电路的工作过程.实验结果表明逆变器主开关和辅助开关能完成软切换.因此,该拓扑结构对于研发高性能谐振直流环节逆变器具有借鉴意义.     

A forward converter topology employing a resonant auxiliary circuit to achieve soft switching and power transformer resetting

This paper presents a forward converter topology that employs a small resonant auxiliary circuit. The advantages of the proposed topology include soft switching in both the main and auxiliary switches, recovery of the leakage inductance energy, simplified power transformer achieving self-reset without using the conventional reset winding, simple gate drive and control circuit, etc. Steady-state analysis is performed herein, and a design procedure is presented for general applications. A 35-75-Vdc to 5 Vdc 100-W prototype converter switched at a frequency of 200 kHz is built to verify the design, and 90% overall efficiency has been obtained experimentally at full load.     

A new single-phase ZCS-PWM boost rectifier with high power factor and low conduction losses

This paper proposes a new single-phase high-power-factor rectifier, which features regulation by conventional pulsewidth modulation (PWM), soft commutation, and instantaneous average line current control. A new zero-current switching PWM (ZCS-PWM) auxiliary circuit is configured in the presented ZCS-PWM rectifier to perform ZCS in the active switches and zero-voltage switching (ZVS) in the passive switches. Furthermore, soft commutation of the main switch is achieved without additional current stress by the presented ZCS-PWM auxiliary circuit. A significant reduction in the conduction losses is achieved because of the following reasons: 1) the circulating current for the soft switching flows only through the auxiliary circuit; 2) a minimum number of switching devices are involved in the circulating current path; and 3) the proposed rectifier uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. Seven transition states for describing the behavior of the ZCS-PWM rectifier in one switching period are described. The PWM-switch model is used to predict the system performance. A prototype rated at 1 kW, operating at 60 kHz, with an input alternating current voltage of 220 V/sub rms/ and an output voltage of 400 V/sub dc/, has been implemented in laboratory. An efficiency of 98.3% and a power factor over 0.99 have been measured. Analysis, design, and the control circuitry are also presented in this paper.     

A novel zero-Voltage-switching PWM boost rectifier with high power factor and low conduction losses

This paper proposes a new single-phase high-power-factor rectifier, which features regulation by conventional pulsewidth modulation (PWM), soft commutation, and instantaneous average line current control. A new zero-voltage-switching PWM (ZVS-PWM) auxiliary circuit is configured in the presented ZVS-PWM rectifier to perform ZVS in the main switches and the passive switches, and zero-current switching in the auxiliary switch. Furthermore, soft commutation of the main switch is achieved without additional current stress by the presented ZVS-PWM auxiliary circuit. A significant reduction in the conduction losses is achieved, since the circulating current for the soft switching flows only through the auxiliary circuit and a minimum number of switching devices are involved in the circulating current path, and the proposed rectifier uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. Nine transition states for describing the behavior of the ZVS-PWM rectifier in one switching period are described. A prototype rated at 1 kW, operating 80 kHz, with an input ac voltage of 220 V/sub rms/ and an output voltage of 400 V/sub dc/ has been implemented in the laboratory. An efficiency of 96.7% and power factor over 0.99 has been measured. Analysis, design, and the control circuitry are also presented in this paper.     

A novel ZCS-PWM power-factor preregulator with reduced conduction losses

This paper proposes a new single-phase high-power-factor rectifier, which features regulation by conventional pulsewidth modulation (PWM), soft commutation, and instantaneous average line current control. A new zero-current-switching PWM (ZCS-PWM) auxiliary circuit is configured in the presented ZCS-PWM rectifier to perform ZCS in the active switches and zero-voltage switching in the passive switches. Furthermore, soft commutation of the main switch is achieved without additional current stress by the presented ZCS-PWM auxiliary circuit. A significant reduction in the conduction losses is achieved, since the circulating current for the soft switching flows only through the auxiliary circuit and a minimum number of switching devices are involved in the circulating current path and the proposed rectifier uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. Nine transition states for describing the behavior of the ZCS-PWM rectifier in one switching period are described. The PWM switch model is used to predict the system performance. A prototype rated at 1 kW, operating 50 kHz, with an input ac voltage of 220 V/sub rms/ and an output voltage 400 V/sub dc/ has been implemented in laboratory. An efficiency of 97.3% and power factor over 0.99 has been measured. Analysis, design, and the control circuitry are also presented in this paper.     

Design and Application for PV Generation System Using a Soft-Switching Boost Converter With SARC

In order to improve the efficiency of energy conversion for a photovoltaic (PV) system, a soft-switching boost converter using a simple auxiliary resonant circuit, which is composed of an auxiliary switch, a diode, a resonant inductor, and a resonant capacitor, is adopted in this paper. The conventional boost converter decreases the efficiency because of hard switching, which generates losses when the switches are turned on/off. During this interval, all switches in the adopted circuit perform zero-current switching by the resonant inductor at turn-on, and zero-voltage switching by the resonant capacitor at turn-off. This switching pattern can reduce the switching losses, voltage and current stress of the switching device. Moreover, it is very easy to control. In this paper, we have analyzed the operational principles of the adopted soft-switching boost converter, and it is designed for PV generation system. Simulation and experimental results are presented to confirm the theoretical analysis.      

Novel zero-voltage and zero-current-switching full bridge PWMconverter using transformer auxiliary winding

A novel zero voltage and zero current switching (ZVZCS) full bridge (FB) pulse width modulation (PWM) converter is proposed to improve the demerits of the previously presented ZVZCS-FB-PWM converters, such as use of lossy components or additional active switches. A simple auxiliary circuit which includes neither lossy components nor active switches provides ZVZCS conditions to primary switches, ZVS for leading-leg switches and ZCS for lagging-leg switches. Many advantages including simple circuit topology, high efficiency, and low cost make the new converter attractive for high power (>2 kW) applications. The operation, analysis, features and design considerations are illustrated and verified on a 2.5 kW, 100 kHz insulated gate bipolar transistor (IGBT) based experimental circuit     

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     

Zero-Voltage and Zero-Current Switching Full-Bridge DC–DC Converter With Auxiliary Transformer

A novel zero-voltage and zero-current switching (ZVZCS) full-bridge phase-shifted pulsewidth modulation (PWM) converter using insulated gate bipolar transistors (IGBTs) with auxiliary transformer is proposed to improve the properties of the previously presented converters. ZVZCS for all power switches is achieved for full load range from no-load to short circuit by adding active energy recovery snubber and auxiliary circuits. The principle of operation is explained and analyzed and experimental results are presented. The features and design considerations of the converter are verified on a 3-kW, 50-kHz IGBT based experimental circuit.     

An improved self-resonant PWM forward converter

This paper presents a forward converter with a nondissipative cell which provides a soft switching converter operation. This approach is based on the principle of self-resonance, that is: an auxiliary voltage source feeds the resonant circuit, charging a capacitor which provides the condition for zero voltage switching (ZVS) turn on and turn off of the switches. The complete operating principle, relevant equations, simulation, and experimental results are presented     

Design of a novel ZVT soft-switching chopper

This paper presents a simple soft-switching chopper scheme with fixed timing control. A near-zero-voltage transition (near-ZVT) switching condition is realized by adding one auxiliary resonant snubber branch to a full-bridge two-quadrant chopper. The turn-off loss is reduced by lossless snubber capacitors in parallel with the main switches. The proposed design approach is to realize true ZVT at the rated load and near-ZVT under all other load current conditions. Computer simulation and hardware experiments have been implemented to verify the proposed concept, and the resulting voltage and current waveforms are shown from 30% to 150% load conditions in this paper. Under near-ZVT switching, the switching loss and dv/dt of the power device can be significantly reduced, and the reverse recovery problem of main switches can be avoided as compared to the hard-switching case. The design criteria for the resonant components are described with a practical example that has been used in a commercial magnetic levitation system. Under different load current conditions, the proposed design methodology has been fully verified with simulation and experimental results     

节能型单相全桥零电流开关谐振极逆变器

为改善以绝缘栅双极型晶体管（Insulated Gate Bipolar Transistor,IGBT）作为开关器件的单相全桥逆变器的效率,提出了一种节能型单相全桥零电流开关谐振极逆变器,在每个桥臂上分别并联1组辅助电路.在工作过程中,主开关和辅助开关都能完成零电流软切换,可消除IGBT拖尾电流造成的关断损耗.分析了电路工作过程,在2kW样机上的实验结果表明开关器件实现了零电流软切换.因此,该拓扑结构可实现以IGBT作为开关器件的单相全桥逆变器的节能运行.     

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...