基于Walsh函数的SHEPWM技术在电流型多电平变流器中的应用

Application of Selective Harmonic Elimination PWM Technique Based on Walsh Function in CSC

随着高温超导储能技术的发展,电流型变流器的储能效率问题必将得到解决,电流型多电平变流器(CSC)将在电力系统中得到广泛应用。本文以一种新型单相五电平变流器为例,研究了SHEPWM技术在电流型多电平变流器中的应用。利用基于Walsh函数把其对应的Fourier域内的非线性超越方程组转化为线性代数方程组,求解出了开关角关于基波幅值的分段线形方程,从而可实现输出电流的特定谐波抑制和在线控制。

With the development of superconductive technology of high temperature, multilevel current source converter(CSC)will be widely used in power system. Taking a single-phase 5-level CSC model for example, Selected Harmonic Elimination Pulse Width Modulation(SHEPWM)techniques applicable to multilevel CSC are studied in detail. The SHEPWM technique based on Walsh transform converters nonlinear equations in the Fourier domain to linear algebraic ones. The piecewise linear relation between current fundamental amplitude and switching angles is obtained, so current regulation and harmonic elimination can be realized online.