基于调制比优化的单相逆变器主谐波滤除研究

摘要

In order to maximumly eliminate the main harmonic of the inverter output voltage,a method of determining modulation ratio is proposed.Firstly,the output voltage of the cascaded multilevel inverter under unipolar frequency multiplication is analyzed by using the double Fourier series theory,and the harmonic distribution of output voltage is deduced.Secondly,a method of selecting the SPWM modulation ratio is proposed to reduce the primary harmonic of the inverter output voltage under the condition that the amplitude of the fundamental wave is constant.Finally,the correctness and effectiveness of the proposed method are validated through software simulation and hardware experiments under different modulation ratios in the cascaded five-level inverter.%为了使逆变器输出电压的主要次谐波得到最大化的消除,提出了一种确定调制比的方法.首先,利用双重傅里叶级数理论,对级联多电平逆变器在单极性倍频SPWM调制下的输出电压进行分析,推导出输出电压的谐波分布情况.然后,在保证基波幅值不变的情况下,提出了一种选取SPWM调制比的方法,使逆变器输出电压主要次谐波降低.最后,在级联五电平逆变器中,对在不同调制比的情况下,通过软件仿真和硬件实验,验证了所提方法的正确性与有效性.