大容量多重化逆变器的输出电压谐波分析

针对目前缺乏对大容量多重化逆变器的输出电压谐波进行全面分析和比较的现状,根据多重化变压器的不同结构,将现有的典型多重化逆变器分为3类并从理论上推导出了它们的输出电压及谐波电压幅值表达式;给出了电压谐波畸变系数与重数和脉冲控制参数间的变化关系;对比分析了它们的电压谐波畸变率。理论和仿真分析结果的一致性表明由三电平逆变桥构成的多重化逆变器不仅能以较低的重数实现高压大容量输出,还可获得满意的电压谐波畸变率,且可有效减小变压器体积、重量和损耗,因而更适用于高压大容量电力电子装置。

Voltage Harmonic Analysis of the Multi-pulse Inverter with Large Capacity

Multi-pulse inverters in which power semiconductors with low switching frequency are used can not only reach high voltage and large capacity but also reduce harmonic distortion and switching losses greatly.In view of the absence of comprehensive analysis and comparison of the multi-pulse inverter output voltage harmonic performance,in this paper,three types of the multi-pulse inverter are classified according to the configuration of interphase transformers which are also called harmonic neutralizing magnetics.Firstly,three kinds of the output voltage and the harmonic voltage amplitude expression are proposed.Secondly,the curves of the output voltage THD(total harmonic distortion) varying with pulse control parameters are presented.Finally,the output voltage THD comparison of multi-pulse inverters is implemented by using the theoretical analysis and simulation method.The results show that the harmonic analysis method is valid and correct.For every multi-pulse inverter,there is a group of pulse control parameters which make the voltage THD least.The output voltage waveform quality of the first type of multi-pulse inverters based on the zigzag transformer is best.Furthermore,the multi-pulse inverter,which consists of three-phase three-level voltage-source inverter bridges connected together with interphase transformers,can be used to obtain the required voltage and power rating,keep the low THD,and decrease the dimension,weight,and loss of the interphase transformer efficiently,so it is more suitable for the power electronic circuit with the high voltage and large capacity.