电容钳位H桥级联多电平逆变器功率均衡控制方法

摘要

针对电容钳位H桥级联多电平逆变器载波层叠SPWM调制方法中存在功率不均衡的问题,对该逆变器各个级联单元的有功功率输出进行理论分析,提出了一种改进载波层叠方式的功率均衡控制方法.该方法在不影响逆变器输出电压波形质量的前提下,通过保证该逆变器各个单元输出电压波形的基波幅值相等的方式,可以在一个输出周期内实现各个级联单元的输出功率均衡.以两单元电容钳位H桥级联多电平逆变器为例,进行了仿真分析和对比研究,详细给出了改进功率均衡控制法与传统控制方法下输出电压谐波失真(total harmonic distortion,THD)和输出功率的对比曲线,以及两种方法下逆变器输出的电压波形及其频谱图,结果验证了该控制方法的可行性与优越性.%In view of the problem of unbalanced power with SPWM modulation of the capacitor clamped H bridge cascaded multilevel inverter ,based on the analysis of active power output ,a power balance control scheme for carrier disposition SPWM strategies of was proposed based on active power analyzed .The scheme achieved the output power balance in one output cycle without effecting the quality of output volt -age,which ensures the fundamental voltage generated by each units in one phase is equal .The cascaded inverter composed by two cells was taken as the examples ,and the scheme was researched and simulated . The output voltage harmonic distortion and the output power of the improved power balance control meth -od and the traditional control method were given in detail ,and the voltage waveform and the spectrum dis-tribution of the inverter under the two methods were given in detail .The results verify the validity and su-periority of the proposed scheme .