【摘要】 大功率高压直流输出变换器对电力电子器件的耐压等级要求较高,导致变换器成本增加、体积增大以及寿命减小。采用器件串联分压的方法成为目前降低器件耐压等级较为可行的方法之一,然而这种方法存在串联器件不均压的问题。本文探讨了大功率高压变换器中整流二极管串联的均压问题,通过对串联二极管等效网络的分析,找出了高压环境下二极管不均压的影响因素,讨论了分布电容及二极管串联个数对电位分布的影响,解释了桥式整流中二极管串联不均压现象,最后给出了不均压的解决方案。仿真和实验结果表明了高压环境下分布电容是造成二极管不均压的主要因素,通过添加均压电阻和均压电容能够有效减小其影响。更多还原

【Abstract】 The high voltage and high power converters require high voltage level of the power electronic devices,which would cause extra costs,large volume and short lifetime.One of feasible methods to derate the voltage of the devices is to use the elements coupled in series currently.However,the serial devices can not get equal voltage sharing.This paper discusses the problem of the voltage sharing in series coupled diodes,and some factors that influence this problem are gotten based on the analysis of the equivalent network of the coupled diodes.The influence of the parasitic capacitance and the number of the coupled diodes are discussed,and the phenomenon of unequal distribution of each diode in bridge rectifier circuit is resolved.At last the solution and the experiment verification are given.The simulation and the experiment indicate that the main factor that causes the voltage of the coupled diodes different under high voltage pressure is the parasitic capacitance,and the influence can be solved effectively by coupling a compensating resistance and a compensating capacitor in parallel with each switch.更多还原