开绕组电机驱动用双三电平逆变器的共模电压差抑制

开绕组电机驱动用双三电平逆变器拓扑在中压大功率变频驱动领域具有较好的优势。针对共直流源的开绕组拓扑共模电压差抑制的问题,提出了一种基于零序注入的SPWM调制策略,将两组逆变器的调制矢量互差120°后分别注入幅值相同的三次零序电压,保证系统任意时刻的低频和高频共模电压差均为零。在此基础上为了解决中点电压脉动问题,需要进一步的零序电压注入,同时不影响系统共模电压差抑制。文中通过仿真和实验证明了该调制策略的可行性和有效性。

The Differential Common Mode Voltage Elimination of Dual Three-Level Converter for Open-End Winding Motor Drives

The topology of the dual three-level converter for the open-end winding motor reflects a better advantage in the medium voltage high power field for AC drives. For the problem of the common mode voltage elimination with the one DC source open-end topology,a sinusoidal pulse width modulation( SPWM)modulation strategy with zero sequence injection is proposed. Two converters’modulation vectors are injected into the zero sequence voltage with the same magnitude and 120o angle difference, which ensures that the low and high frequency common-mode( CM)differential value is zero at any time. On this basis,in order to solve the neutral point voltage ripple,further zero sequence voltage injection is needed for the neutral point control with no effect on the differential value of CM suppression. Simulation and experimental results confirm the feasibility and validity of this modulation strategy.