基于开关函数法的新型换流变压器谐波分析

Harmonics Analysis of New Converter Transformer Based on Switching Function Method

介绍一种新型换流变压器,分析了其拓扑结构的特点,并简要地阐述了新型换流变压谐波屏蔽原理。重点分析了阀侧接入和未接滤波器时,网侧电流和阀侧负载电流的矩阵变换关系。在此基础上,推导了新型换流变压器网侧和阀侧电流的开关函数表达式,详细地计算了阀侧和网侧汇流处基波和谐波电流的幅值和相位。通过与接入滤波器时谐波电流的对比分析,显示了新型换流变压器将谐波电流抑制在阀侧而不让其流入网侧的优越性。通过对比仿真结果,表明了开关函数法用于新型换流变压器谐波计算理论的正确性,这也为新型换流变压器结构和参数的进一步设计提供了精确的科学数据。

A new converter transformer was presented. Its topological structure and operating principle of shielding harmonic current were introduced. The matrix relationship of primary current and load current was derived when the filters of convertor side are used or not in the system. Then the switching function of AC side and convertor side currents was deduced, by use of which the amplitude and phase of the harmonic current of convertor side and AC side were calculated. The calculation results show that the novel converter transformer can prevent the harmonic current at convertor side flowing to AC side. The comparison with simulation results indicates the reliability of the switching function method used in calculation of harmonic current, which supplies precise data and parameter for the further design.