考虑死区的三相PWM逆变器共模电压抑制技术

Common-mode voltage suppression algorithm for three-phase PWM inverter in consideration of dead-band

为了实现对三相脉宽调制(PWM)逆变器死区条件下输出共模电压尖峰的有效抑制,提出混合调制算法.分析死区对临近矢量PWM(NSPWM)和等效零矢量PWM(AZSPWM1)输出共模电压的影响,揭示共模电压尖峰出现时需满足的负载功率因数和所处的扇区位置.为了消除共模电压尖峰,限定有关电压矢量的最小作用时间,并根据伏秒平衡原理,分别对NSPWM和AZSPWM1进行修正.分别分析最小作用时间对修正的NSPWM和AZSPWM1适用调制范围的影响,并将二者结合组成混合调制算法.结果表明:该混合调制算法可在全功率因数条件下宽调制范围内实现对共模电压尖峰的有效抑制.

A hybrid modulation algorithm was proposed in order to eliminate the spikes incurred by the dead-band on the common-mode voltage（CMV）output of three-phase pulse with modulation（PWM）inverter.The CMV output variations for both near state PWM（NSPWM）and active zero PWM1（AZSPWM1）involved with dead-band were analyzed.The regions in sectors and the related load power factor conditions when the CMV spikes emerge were deduced.The minimal time durations of the active voltage vectors were limited to eliminate the CMV spikes.Both the NSPWM and AZSPWM1 were modified according to the voltage-second integral principle.The influences brought by the limitations on the linear modulation range of both NSPWM and AZSPWM1 were analyzed respectively.Then the modified NSPWM and modified AZSPWM1 were combined as the hybrid modulation algorithm.The experimental results show that the CMV spikes caused by the dead-band are rejected by the proposed algorithm in full load power factor conditions and a wide linear modulation range.