H桥级联型整流器电容电压平衡控制策略

摘要

针对H桥级联型整流器( cascaded H-bridge rectifier, CHBR)的电容电压平衡问题,在建立CHBR数学模型的基础上,研究了一种基于PI控制的直流侧电容电压平衡控制策略,采用载波移相调制策略( carrier phase-shifted SPWM,CPS-SPWM) ,理论推导出调制比与有功功率之间的关系,得出该电容电压平衡控制的均压范围.搭建了三模块CHBR的仿真模型和试验样机,试验结果验证了该算法具有较好的均压能力.%Cascaded H-bridge rectifier( CHBR) are usually used in the high-voltage situations such as APF ( Active Power Filter) and PET ( Power Electronic Transformer) . Further, the capacitor voltage balancing is an important issue of this topology. Based on the mathematical model of CHBR, a novel PI-based capacitor voltage balancing method is proposed with the carrier phase-shifted SPWM technique. The relationship between the modulation index and the active power of cells is deduced by the mathematical analysis, and the voltage range of proposed capacitor voltage balance control is derived. A three-module CHBR simulation model, as well as an experimental prototype, is built. Experimental results indicate that the presented method has good performance on the capacitor voltage balance.