转移函数应用于变流器的谐波分析

运用转移函数法分析变流器两侧的谐波,考虑了晶闸管的换相过程以及触发角由于某种控制需要而受到余弦信号的调制过程,为工程实际中谐波的估算提供了方便和较为精确的方法.本文对转移函数作了简明的论述和推导;运用转移函数得到的谐波分析模型,对变流器端的谐波构成及其含量进行了分析;最后用仿真计算验证了公式的有效性和精确性.

Harmonic Analysis Using Transfer Function on the Converter

Transfer function (TF) is an accurate and convenient technique to evaluate harmonics on both alternating current (AC) and direct current (DC) sides of a converter, as it considers the commutation period between the thyristors and the firing angle variation for some control requirement in the circuit. This paper provides the derivation of transfer function suitable for 6-pulse rectifier in details. Then, it establishes the harmonic analysis model for a rectifier circuit with the obtained transfer function, in which the modulated firing angle by cosine-signal is considered. It also shows how the firing modulation can influence the characteristic and non-characteristic harmonics as well as interharmonics on both sides of the converter. Two examples, considering firing modulation or not, are given which show how to calculate harmonics, and comparisons are made with simulation software PSCAD/EMTDC as a check on the accuracy of the TF method.