混合九电平逆变器的脉冲宽度调制

为实现混合九电平逆变器在变压变频调速场合中的应用,该文在分析混合九电平逆变器脉冲宽度调制(PWM)方法的基础上,深入研究了混合九电平逆变器的死区效应,并提出一种改进的补偿方法。同时,为保证混合九电平逆变器的运行安全,采用注入零序电压的方法来控制H桥辅助逆变电路的电容电压平衡。实验结果验证了电容电压平衡控制方法的有效性,而且采用改进的死区补偿方法能够补偿死区效应导致的不正常脉冲,使得混合九电平逆变器能输出较好的电压波形,输出电压总谐波畸变率小于3%。

Pulse width modulation for hybrid 9-level inverters

The dead time of hybrid 9-level inverters was analyzed to develop a method to apply hybrid 9-level inverters to variable-voltage, variable-frequency drive systems. The method is based on the application of the pulse width modulation (PWM) method for hybrid 9-level inverters. The zero-sequence voltage was related to the reference voltage to balance the capacitor voltage in the H-bridge assistant inverter to ensure hybrid 9-level operational security. Experimental results demonstrated the effectiveness of the capacitor voltage balance control method. The modified dead time compensation method for the hybrid 9-level inverter effectively compensated for the abnormal pulse induced by dead time effect. The hybrid 9-level inverter then output better waveforms with a total harmonic distortion of the output voltage of less than 3%.