串联H桥多电平逆变器特定谐波控制组合法

针对串联H桥多电平逆变器输出阶梯电压波形中存在低频谐波的问题,提出了一种特定谐波控制组合法。该方法以梯形波调制为基础,利用等面积法原理和谐波注入组合法,通过简单的三角公式递推计算获得实现特定谐波消除的开关导通角,并对开关导通角进行优化,从而实现谐波抑制。以三相九电平串联H桥逆变器为例,进行了仿真和实验,结果验证了该方法的可行性和有效性。

Combination method of selective harmonic control for cascaded H-bridge multilevel inverter

In view of problem of low frequency harmonic in step voltage waveform of output of cascaded H-bridge multilevel inverter,a combination method of selective harmonic control was proposed.On the basis of trapezium waveform modulation,the method uses combination method of equal area principle and harmonic injection,switching conduction angle for selective harmonic elimination can be easily obtained by simple calculation of trigonometry formula deduction and optimized,so as to realize harmonic suppression.Taking three-phase nine-level cascaded H-bridge inverter as an example,simulation and experiment were conducted,and the result shows feasibility and validity of the method.