多谐振软开关全桥Boost变换器

提出一种利用多谐振实现开关管软开关的全桥Boost变换器.其将变压器漏感作为谐振电感,利用电感与电容谐振实现桥臂开关管和箝位开关管的软开关.桥臂开关管工作于零电流开通与零电压关断状态.有源箝位电路既可抑制变换器工作时可能出现的振荡电压,又可将箝位电容吸收的能量返还回主电路,且箝位开关管工作于零电压开通与零电流关断状态.最后利用硬件实验验证了其多谐振软开关特性.     

基于UPC1909的有源箝位软开关变换器

在常规的硬开关电路中,由于变压器漏感及寄生电容的影响,常常在开关转换瞬间会产生很高的电压尖峰。本文采用有源箝位反激式变换器电路,实现了零电压零电流(ZVZCS)软开关变换,使电压尖峰得到了抑制。该电路成功地应用了UPCI909控制芯片,简化了传统的驱动电路。实验结果表明,主开关管两端电压被箝位在一定数值,实现了零电压零电流开关,效率达到90％。     

节能型三相桥式零电流开关整流器

为使三相桥式整流器实现节能运行,提出了一种节能型三相桥式零电流开关整流器拓扑结构,在各相桥臂上的辅助谐振电路处于工作状态时,整流器的开关器件能完成零电流软关断.三相桥式整流器通常以绝缘栅双极型晶体管（Insulated Gate Bipolar Transistor,IGBT）作为开关器件,实现零电流软关断能消除IGBT拖尾电流产生的关断损耗.分析了电路工作过程,在三相3kW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作为开关器件的三相桥式整流器的节能运行.     

了解主开关主动式箝位正向器转换

＂主动式箝位＂的开关周期,包含开关开启时电路的电压和电流,主要适用于主动式箝位正向转换器输出电感中存在连续电流的情况。图1所示的电路,正电流以箭头表示,并显示开关Q1（主动式箝位开关）和Q2．以及本身固有的本体二极管和汲源极电容。另外也显示Q3及Q4闸源极电容．因为这些电容会影响电流。     

基于有源箝位的IGBT过电压抑制技术

在介绍绝缘门极双极性晶体管(IGBT)在关断过程中产生过电压原理基础上,分析了传统的过电压抑制方法存在的问题,给出了一种基于有源箝位的IGBT过电压抑制策略。所给出的有源箝位电路由瞬态电压抑制器(TVS)构成,位于IGBT的集电极与门极之间。基于Saber的仿真结果证实了该策略可将IGBT关断时的过电压箝位在瞬态电压抑制器的设定值,能有效地减小IGBT关断时产生的过电压。     

一种新型零电流PWM Buck开关电路的设计

提出一种新型零电流开关PWM Buck电路,对其拓扑结构和工作原理进行了详细分析,仿真结果证明该电路中所有的开关管和二极管均能在软开关条件下完成导通和关断,且具有很小的电流应力,能有效解决IGBT关断时存在的"拖尾电流"问题.     

Boost ZCT-PWM变换器的改进及仿真分析

针对传统的Boost ZCT-PWM变换器中存在的主开关管硬开通和辅助开关管硬关断的问题,提出一种改进型的Boost ZCT-PWM变换器,使主开关管零电流开通,辅助开关管零电流通断,并且特别适用于IGBT作为开关器件的高电压、大功率应用场合。分析电路的工作原理并用PSpice仿真软件进行仿真研究。仿真结果表明所有开关器件实现了软开关,变换器的效率得到提高。     

三极管RBSOA测试仪的设计与实现

主要介绍了三极管反向偏压安全工作区(RBSOA)测试仪的硬件结构和相应的软件实现。该测试仪主要基于三极管的RBSOA及三极管的开关原理,并结合实际测试生产环境,设计了大功率电源供电电路、电流驱动电路、电压箝位电路、电流电压检测电路、单片机控制电路以及PC机的用户界面这6大模块。该测试系统采用了电感诱导控制电流和箝位电路限压,成功实现了对三级管集电极电流Ic和集电极-发射极电压Vce的控制;使用多点采样法,实现了可靠的电流电压检测。经过长期对不同型号和同一型号不同状况的三极管测试,成功验证了测试仪的性能和可靠性。     

一种改进的二极管箝位型多电平变换器拓扑

多电平电路在高压大功率领域的拓展受到其复杂电路拓扑的制约,因此近年来不断有新型多电平电路结构被提出。本文在传统多电平逆变器拓扑结构的基础上,提出了一种新型单相七电平电压源逆变器拓扑。新型电路拓扑是在传统的单相全桥五电平箝位二极管电路基础上,增加了两个开关器件,利用10个开关器件以及4个箝位二极管产生了7种不同的电平输出。详细分析了该逆变器的拓扑结构,给出了PWM控制策略。最后通过仿真实验验证了这种拓扑的可行性。该逆变器对传统箝位二极管逆变器在结构上做出了优化。     

大功率单相有源功率因数校正主电路的研究

在实际应用中，传统型单相有源功率因数校正主电路存在二极管反向恢复产生的电流冲击等问题。文中比较了三种改进型大功率单相有源功率因数校正主电路，其中包括串联高压碳化硅肖特基二极管主电路，从新型器件应用、主电路修正和软开关三方面分别解决电流冲击等问题，提高了大功率功率因数校正主电路的可靠性。     

New soft switching techniques for three phase voltage source inverters

Three new composite soft switching configurations for power inverters are presented. Each configuration incorporates an inductor to limit switch di/dt and diode reverse recovery current at turn-on, and realizes zero current switching at turn-off, with minimum active devices or passive components. Different features and applications of the configurations are considered. Simulations of three different inverter configurations are performed using PSpice and circuit switching waveforms are given, and experimental results confirmed analysis and simulations.     

软特性650V IGBT：低电磁干扰和电压尖峰的优化器件

近年来,功率半导体厂商致力于提高器件的开关速度,这带来了开关损耗降低和系统能效提升的益处。这些功率器件需要优化的直流电路寄生电感（Ls）。为了满足具有大电流的高功率应用的需求,推出了一种全新的芯片650V IGBT4,旨在提供更大的设计自由度。这款全新的IGBT4器件具备更好的关断软度,并且由于关断电流变化率di／dr...     

Overload robust IGBT design for SSCB application

This paper presents an optimised power semiconductor architecture based on the CIGBT approach to be used in solid-state circuit breaker (SSCB) applications where the conduction losses have to be as low as possible without compromising the forward voltage blocking capability. Indeed, a high overcurrent turn-off and short-circuit withstand capabilities have to be ensured. Starting from a standard NPT-IGBT design for switching applications, the results show that the proposed device, which is optimised by the application of the individual clustered concept, offers a reduction in conduction losses of 13%, without compromise on voltage blocking capability. An original design solution is implemented to further ensure short-circuit and overload turn-off capabilities at maximum ambient temperature and twice the nominal rated current.     

IGBT modules robustness during turn-off commutation

The behaviour in terms of robustness during turn-off of power IGBT modules is presented. The experimental characterisation is aimed to identify the main limits during turn-off in power IGBT modules in typical hard switching applications. In this paper an experimental characterization of high power IGBT modules at output currents beyond RBSOA, at high junction temperatures and under different driving conditions is presented. Several devices of different generations, current and voltage ratings have been considered. The experimental characterisation has been performed by means of a non-destructive experimental set-up where IGBT modules are switched in presence of a protection circuit that is able to prevent device failure at the occurrence of any possible instable behaviour. The experimental analysis confirms the very good robustness of high power IGBT modules which can withstand large current overstress well beyond the declared RBSOA limits even at temperatures larger than those one declared by manufacturers. A comparison between IGBT device generation is also presented.     

高速脉宽调制器的原理及应用

本文介绍了ＳＷ１８２５高速脉宽调制器的特点和原理，列举了典型应用的接线图；并对电路应用中的功耗、工作稳定性等进行了讨论。     

Utilization of an active-clamp circuit to achieve soft switching inflyback converters

Flyback derived power convertor topologies are attractive because of their relative simplicity when compared with other topologies used in low power applications. Incorporation of active-clamp circuitry into the flyback topology serves to recycle transformer leakage energy while minimizing switch voltage stress. The addition of the active-clamp circuit also provides a mechanism for achieving zero-voltage-switching (ZVS) of both the primary and auxiliary switches. ZVS also limits the turn-off di/dt of the output rectifier, reducing rectifier switching losses, and switching noise due to diode reverse recovery. This paper analyzes the behavior of the ZVS active-clamp flyback operating with unidirectional magnetizing current and presents design equations based on this analysis. Experimental results are then given for a 500 W prototype circuit illustrating the soft-switching characteristics and improved efficiency of the power converter. Results from the application of the active-clamp circuit as a low-loss turn-off snubber for IGBT switches is also presented     

A physical and circuit level approach for modeling turn-offcharacteristics of GTOs

In this paper, we present physical and circuit models, which are related via their parameters, to characterize the gated turn-off characteristics of thyristors. The physical model provides physical insight to the mechanism of turn-off in single islands, and investigates analytically, the dependence of storage time on external variables (anode and gate currents) and physical device parameters and dimensions. Such a characterization is useful since the current crowding effect (that limits current controllability in a multi-emitter structure) depends on the turn-off behavior of the unit cells. The circuit level approach provides a model which can be incorporated into CAD programs (such as SPICE) that can be used by application engineers to design a variety of power electronic circuits such as static VAr compensators (SVCs), The parameters of the circuit model are based on the physical model parameters and thus reflect the physical device properties and dimensions     

A soft switching active snubber optimized for IGBT's in singleswitch unity power factor three-phase diode rectifiers

This paper describes a soft switching active snubber for an IGBT operating in a single switch unity power factor three-phase diode rectifier. The soft switching snubber circuit provides zero-voltage turn-off for the main switch. The high turn-off losses of the IGBT due to current tailing are reduced by zero-voltage switching. This allows the circuit to be operated at very high switching frequencies with regulated DC output voltage, high quality input current and unity input power factor. Simulation and experimental results are included     

Actively clamped zero-current-switching quasi-resonant convertersusing IGBTs

Conventional zero-current-switching quasi-resonant power converters (ZCS-QRCs) suffer from the disadvantages of high switch current stress and variable switching frequency. This paper proposes the use of a “current-clamping circuit” to overcome these disadvantages. By incorporating such a circuit into the family of ZCS-QRCs, a new family of actively clamped ZCS-QRCs using insulated gate bipolar transistors (IGBTs) is derived. These power converters feature high (and constant) switching frequency and zero-current turn-off (without increased current stress), which are particularly useful for high-power applications where minority-carrier semiconductor devices (such as IGBTs and bipolar junction transistors) are used as power switches. The design criteria, simulation and experimental results are reported     

Class DE current-source parallel resonant inverter

This paper introduces a Class DE current-source parallel resonant inverter, along with its design procedure and experimental results. This circuit offers several desirable features. First, the proposed circuit lacks harmonic components of input current over the voltage-source inverters. Second, the source pin of the MOSFET is directly connected to the ground, so that it is not necessary to use a complicated gate-drive circuit. Third, by maintaining zero-current switching, power loss by the parasitic inductor at turn-off decreases. The measured efficiency is over 90% at the output power of 3.5 W and the operating frequency of 0.5 MHz