变压器辅助换流的三相节能型谐振极逆变器

在谐振极软开关逆变器辅助电路的换流过程中,为避免剩磁通的累积导致变压器铁心饱和,提出了一种变压器辅助换流的三相节能型谐振极逆变器的拓扑结构,在二极管反向阻断的作用下,变压器的磁化电流无法形成稳态环流,从而使变压器中的能量全部向负载转移,磁化电流最终变化到零,实现了变压器的去磁复位.此外,逆变器的主开关和辅助开关可以分别完成零电压软切换和零电流软切换.分析了电路的换流过程.实验结果表明逆变器的开关器件完成了软切换,变压器磁化电流能减小到零.该拓扑结构对于研发高性能谐振极逆变器具有一定的参考价值.     

一种新的移相全桥零电压开关PWM变换器

对于移相全桥零电压开关PWM变换器,在全负载范围内实现所有开关器件零电压开关和减少占空比丢失之间是矛盾的。如果在电路中增加一个辅助电路,根据负载情况在续流期间为滞后桥臂的零电压开关提供能量,能在全负载范围内实现所有开关器件的零电压开关和减少占空比丢失,但电路中存在严重的环流问题。文中提出新的拓扑结构通过增加一个双向开关和相应的驱动电路,有效地减少了环流带来的损耗。实例分析和仿真验证了这种拓扑的优点。     

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.     

中小功率三相高频节能型谐振直流环节逆变器

为使中小功率三相逆变器实现在高开关频率下的节能运行,首次提出了一种新型三相谐振直流环节逆变器拓扑结构.设置在逆变器直流环节的辅助电路参与换流过程时,桥臂输入端的直流环节电压能周期性形成零电压状态,主开关和辅助开关都能完成零电压软切换.在高频金属氧化物半导体场效应晶体管（Metal Oxide Semiconductor Field Effect Transistor,MOSFET）作为该逆变器的开关器件时,实现零电压软切换能消除MOSFET的容性开通损耗,有利于优化逆变器效率.文中分析了电路的工作流程.2.5kW样机上的实验结果表明开关器件都处于零电压软切换.因此,该拓扑结构对于研发高性能的中小功率三相逆变器具有参考价值.     

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.     

高效率三相谐振极逆变器

为优化三相逆变器的性能,提出了一种高效率三相谐振极逆变器.在各相桥臂上增设的辅助谐振电路参与逆变器的换流过程时,桥臂上的各主开关并联的谐振电容的电压能周期性形成零状态,使主开关能完成零电压软切换,而且辅助谐振电路中的各开关器件也能完成零电流软开通和零电压软关断.开关器件实现软切换能降低开关损耗,从而使逆变器实现高效率运行.文中分析了电路的工作流程.3kW样机上的实验结果表明主开关和辅助开关都处于软切换.因此,该拓扑结构对于研发高性能三相逆变器具有借鉴价值.     

非对称半桥式开关电源的分析与设计

非对称半桥电路拓扑采用脉冲宽度调制技术,具有易实现零电压开关的优点,可广泛应用于家用电器,汽车电子等领域中。文中首先介绍了非对称半桥电路的工作原理,接着对其进行了稳态分析,重点给出了一个非对称半桥式开关电源的设计过程。考虑到拓扑结构参数和零电压开关的影响,对电路的输出电压进行了修正。此外,谐振电感和死区时间是确保零电压开关实现的两个重要参数,文中给出了其实际的设计过程,并通过仿真证明了其实现的可行性。     

新型单相全桥谐振直流环节逆变器

为改善单相全桥逆变器的性能,提出了一种新型单相全桥谐振直流环节逆变器.位于直流环节的辅助电路能提升直流母线电压稳态值,减少直流母线电压的零状态对直流电压利用率的负面影响.文中分析了逆变器的换流过程.实验结果表明开关器件完成了软切换,逆变器性能得到了改善.     

一种采用无源辅助电路的移相全桥变换器

文章研究了一种采用无源辅助电路的零电压开关移相全桥变换器,它是在传统全桥拓扑上加入了由电容和电感组成的无源辅助电路,从而可以在整个输入电压和全负载范围内实现原边所有开关管的零电压开关。文中详细分析了该变换器的工作原理及其特性,并对辅助电路参数进行了设计。在此基础上,设计完成了一台1.2kW（50V/24A）,开关频率为100kHz的样机,实验结果验证了该变换器的优越性。     

LLC谐振半桥变换器的设计

LLC谐振半桥变换器可以在全电压范围内、全负载条件下使得初级端 MOSFET实现ZVS（零电压开关）,次级整流二极管实现ZCS（零电流开关）,减少了开关损耗,大大提高了效率。而且在输入电压和负载范围变化比较大的情况下,其开关频率变化较小,有利于主参数的设计。这种变换器通常应用在高频功率变换领域。文中首先使用 FHA（基波近似原理）进行 LLC谐振半桥变换器的建模,然后分析了如何对变换器中的电气参数进行选择,最后设计了一个工作在70~150 kHz频率下300 W的 LLC谐振变换器。     

A 1-MHz Zero-Voltage-Switching Asymmetrical Half-Bridge DC/DC Converter: Analysis and Design

The asymmetrical half-bridge (AHB) topology discussed in this paper is one of the complementary driven pulse-width modulated converter topologies, which presents an inherent zero-voltage switching (ZVS) capability. In the previous work, the ideal operation of the converter and the ZVS realization process have been analyzed. However, the influence of the circuit parasitics on the output voltage drop and the design constraints of the circuit parameters to ensure the ZVS operation have not been investigated. The minimum load needed to ensure the ZVS operation is also not readily available. This paper presents a detailed and practical design for a 1-MHz AHB converter. A revised voltage transfer ratio of the converter is derived considering the influence of circuit parasitics and the ZVS transition. Two circuit parameters responsible for maintaining the ZVS operation are the transformer leakage inductance and the interlock delay time between the gate signals of two switches. A design method of the two parameters is proposed, which can ensure the ZVS transition. The possible ZVS range of the load variation is also investigated. A 50-W AHB converter with 1-MHz switching frequency was constructed, and a maximum efficiency of 91% was achieved.     

Interleaved ZVS Converter With Ripple-Current Cancellation

In this paper, an interleaved soft-switching converter with ripple-current cancellation is presented to achieve zero- voltage-switching (ZVS) turn-on and load current sharing. In order to achieve ZVS turn-on, an active snubber is connected in parallel with the primary winding of the transformer. The energy stored in the transformer leakage inductance and magnetizing inductance can be recovered so that the peak voltage stress of switching devices is limited. The resonance at the transition interval is used to realize ZVS turn-on of all switches. In order to achieve three-level pulsewidth-modulation (PWM) scheme, an addition fast-recovery diode is used in the converter. Three-level PWM scheme can reduce the ac ripple current on the output inductor such that the output inductor can be reduced. The current-doubler rectifier is adopted in the secondary side of the transformer to reduce the transformer secondary-winding current and output voltage ripple by canceling the current ripple of two output inductors. The output voltage is controlled at the desired value using the interleaved PWM scheme. These features make the proposed converter suitable for the dc-dc converter with high output current. The operation principles, steady state analysis, and design equations of the proposed converter are provided in detail. Finally, experiments based on a 600-W (12 V/50 A) prototype are provided to verify the effectiveness and feasibility of the proposed converter.     

Off-Nominal Operation of Class-E Amplifier at Any Duty Ratio

Design equations for satisfying the suboptimum operating condition, i.e., only the zero-voltage switching (ZVS) condition, of a class-E amplifier with a linear shunt capacitance at any duty ratio are derived. By exploiting the suboptimum class-E operation, various amplifier parameters such as operating frequency, output power, load resistance, and component values can vary, while the ZVS operation and high efficiency can be achieved. An example of a design procedure of the class-E amplifier is given. The theoretical results were verified with PSpice simulation and an experiment.     

A high-performance ZVS full-bridge DC-DC 0-50-V/0-10-A power supplywith phase-shift control

This paper presents a high-performance DC-DC switching mode power supply designed to deliver a regulated 0-50 V/0-10 A output. The proposed power supply is based on a modified version of the zero-voltage switching (ZVS) full-bridge (FB) phase-shift DC-DC converter, which incorporates commutation auxiliary inductors to provide ZVS for the entire load range as well as a commutation aid circuit to clamp the output diode voltage. The control strategy is based on two control loops operating in cascade mode. The inner loop maintains a regulated output current, whereas the external voltage loop regulates the output voltage, independently of load and input-voltage changes. In order to obtain a high-reliability converter, the control circuit has been implemented using just two integrated circuits (ICs). The phase-shift regulator UC3875 IC generates the gate drive signal to the MOSFET's. The control loop regulators are implemented using the TL074 IC. A theoretical analysis was conducted, and experimental results were obtained for a 0-50 V/0-10 A power supply operating at 100 kHz     

Analysis of Two Continuous Control Regions of Conventional Phase Shift and Transition Phase Shift for Induction Heating Inverter under ZVS and NON-ZVS Operation

This paper proposes an analysis of two continuous control regions of conventional phase shift and transition phase shift for a full-bridge series resonant inverter operating under zero voltage switching (ZVS) and nonzero voltage switching (NON-ZVS) conditions with the load of induction heating. A number of circuit operations for the cases of conventional phase-shift and transition phase-shift control regions under ZVS and NON-ZVS conditions are analyzed first. Various voltage and current equations of the operating circuits are then obtained and used for calculation of the waveforms with the aid of the MATLAB program. The calculated waveforms make possible the consideration of some important circuit parameters that are used to determine ZVS or NON-ZVS conditions. The theoretical results and the proposed method are also verified by experiments, using a prototype test set in our laboratory.      

基于TMS320F28335的恒流型馈能式电子负载的设计

针对电源设备出厂老化测试电能浪费问题,设计了一种基于TMS320F28335DSP的恒流型馈能式电子负载。描述了一种原边带箝位二极管的ZVS移相全桥变换器的工作特点,采用了一种简便易行的移相波形数字控制方法 ;基于DC/DC电压前馈、DC/AC电压电流双环控制方法,研制出一台3.5 kW试验样机。实验结果表明:该系统性能稳定、调节速度快,能很好地满足测试老化及馈网要求。     

Performance characteristics of the full-bridge zero voltageswitching PWM resonant converter

The authors present the exact analysis of the full-bridge zero voltage switching (ZVS) pulse width modulated (PWM) converter by using the state-plane technique. Based on the analysis, they derive the necessary conditions for ZVS operation and the performance characteristics of the converter in terms of characteristic curves from which the converter design procedure can be formulated. The performances of the converter operating outside the limits of ZVS operation, including the switching loss and the attainable efficiency under different load conditions, are also given. The analytical work is confirmed by experimental results     

Surge analysis of induction heating power supply with PLL

Surges are undesirable with respect to both the reliability and the efficiency of power devices. In this paper, the surge mechanism of an induction heating power supply is studied. First, a modified phase locked loop (PLL) controller is proposed such that the changing resonant frequency of the heated load can be tracked correctly and the zero voltage switching (ZVS) can be reliably maintained simultaneously. Then, a very simple and practical surge model is proposed. Surge analyses for both ZVS and non-ZVS modes are made in sequence. It is found that the extra energy built up in the line inductance during the reverse recovery process of the diodes plays a very important role in generating huge voltages. Finally, some simulation and measured results are provided to verify the validity of the proposed surge model     

Zero-voltage-switching PWM three-level converter with current-doubler-rectifier

This paper proposes a zero-voltage-switching (ZVS) pulse-width modulation three-level converter with current-doubler-rectifier, which achieves ZVS for all the switches under wide load range and in a wide line range. The rectifier diodes commutate naturally, therefore no oscillation occurs. The determination of the output filter inductance and the blocking capacitor is discussed in details. The experimental results are presented to verify the operation principle of the proposed converter.