混合CHB逆变器优化调制策略的研究

Research on Hybrid CHB Inverter Optimization Modulation Method

在载波层叠脉宽调制(LS-PWM)的基础上提出一种混合频率优化调制策略,其中,高压单元采用正负反相层叠(POD)的控制方法,低压单元采用一种类似单极倍频的方法,并对正弦脉宽调制(SPWM)所得脉冲进行了逻辑运算与组合,不仅有效解决了传统混合调制所产生的电流倒灌和能量反馈的问题,而且改善了在混合频率调制下由于高压单元频率降低,输出相电压谐波性能较差的问题,从而降低了逆变器输出电压低次谐波的含量,提高了逆变器输出电能质量。最后搭建了Matlab/Sinmlink仿真模型和实验平台,仿真和实验研究证实了该调制策略的有效性和切实性。

A hybrid frequency optimization modulation strategy based on level-shifted pulse width modulation ( LSPWM ) is pro posed. The high-voltage unit adopts the phase opposite disposition ( POD) control method, and the lowvoltage unit adopts a method similar to the single-pole frequency multi plication. The logic operation and combination of the pulses obtained by sinusoidal pulse width modulation ( SPWM) not only effectively solve the problem of current backflow and energy feedback caused by traditional hybrid modulation, but also improve the harmonic characteristics of output phase voltage due to the frequency reduction of high voltage unit under mixed frequency modulation.The poor problem reduces the low harmonic content of the inverter output voltage and improves the quality of the inverter output power.Finally, the Matlab/Simulink simulation model and experimental platform are built.The simulation and experimental research confirm the validity and practicality of the modulation strategy.