中文摘要：

为了解决级联整流器的输出电压均压问题,改进了一种基于比例积分（Proportional Integral,PI）控制器的直流电压均衡方法,并将其应用于单相二极管箝位三电平级联整流器中.以三模块级联整流器为例,利用Matlab/Simulink进行了系统仿真,同时搭建了一套小功率实验平台并且实现了实验验证.仿真和实验结果表明：在采用改进的直流电压均衡控制算法下,可以有效地实现直流侧电压稳定,而且经改进的直流电压均衡控制算法更加简单,方便向更多级联模块扩展.

英文摘要：

Recently,it is a research hotspot how to keep output DC voltage balance for a cascaded rectifier system. To solve this problem,an improved DC voltage balancing strategy based on PI（ Proportional Integral） controller has been proposed and this method is applied to single-phase diode-clamped threelevel cascaded rectifier system. Three-module cascaded rectifier systems that includes simulation system based on Matlab / Simulink and low power experimental system are presented. The simulation and experimental results show that the DC voltages can be kept stable by applying the improved control strategy adopted. Furthermore,the improved control strategy is quite simple,and it is easy to be applied to more cascaded rectifier system.