三相四线制变流器非典型谐波产生机理探析

Non-characteristic Harmonic Analysis of Converter with Three-phase Four-wire Connection

变流器接线方式的改变直接影响变流器交、直流侧的谐波频率特征,甚至会出现幅值较大的非典型谐波分量。三相四线制整流电路的实际工作过程可等效为两个半波整流电路的叠加,首先分析了三相四线制变流器的工作过程,推导了其等效解析电路模型。并通过建立半波整流电路的谐波分析模型,推导其交、直流侧的谐波特征,揭示了各次谐波的产生机理。并对实际变频器工程案例的非典型谐波的产生过程进行溯源分析,指出谐波通道的存在是各非典型谐波产生的直接原因,并通过截断谐波通道的方法有效解决了实际工程中出现的较大的3次谐波问题。最后的现场测试结果和仿真实验均有效验证了理论分析的正确性和有效性。

The harmonic traits of converter is affected by the system connection,big non-characteristic harmonic will emerge,and the converter with three-phase four-wire connection can be regard as the superposition of two half-wave rectifiers. We deduced the equivalent circuit of the converter and analyzed the working course. Based on the harmonic analysis modeling,the harmonic generation mechanism and its frequency traits of the converter were revealed. Considering an actual engineering case of inverter,we traced to the source of the production course of the harmonic,and pointed out that the existing of the channels is the direct cause of the non-characteristic harmonic,through cutting off the channel,the 3th harmonic is restrained immediately. Finally,the practical test and simulation experiments prove the validity of the theory reasoning.