无共模电压SVPWM多桥臂逆变器的拓扑结构演化与电机性能研究

三相开放式绕组永磁同步电动机(PMSM)可采用单电源双逆变器供电,与传统单逆变器供电的PMSM相比具有可选电压矢量多及控制方法灵活等优点,有利于改善电机驱动性能,但逆变器桥臂数量较多,硬件结构复杂。为此,针对无共模电压空间矢量脉宽调制(SVPWM)控制方法,对单电源双逆变器(即六桥臂)驱动拓扑结构进行演化,逐步减少桥臂数量,并对比分析各演化结构驱动下的电机性能。各演化结构虽然引入了额外的零序电流通路,但在无共模电压SVPWM控制下没有零序电压激励,因此并无零序电流产生,故拓扑结构的演化并不影响电机控制性能。该拓扑结构演化不仅为逆变器与电机绕组的选型设计提供参考,还揭示了无共模电压SVPWM的本质特性。

Investigation of Topology Evolution of Common-Mode-Voltage-Free SVPWM Multi-Leg Inverter and Motor Drive Performance

Compared with a traditional single inverter-fed permanent magnet synchronous motor( PMSM), the 3-phase open-end winding PMSM driven by single DC supply and dual inverters is benefited from more applicable voltage vectors,more flexible control method,as well as better drive performance,but suffers from the larger number of inverter legs and more complicated hardware structure. Therefore,in this paper,the drive topology of single-supply dual-inverter,i. e. six-leg inverter,with common-mode-voltage-free( CMVF)space vector pulse width modulation( SVPWM)is evolved so as to eliminate some of the inverter legs,whilst the motor performance with each evolved topology is comparatively analyzed. It is seen that the evolved topologies induce extra paths for the zero-sequence current which,however,is not actually generated due to the absence of the zero-sequence voltage under the CMVF SVPWM control. Thus,the motor performance is hardly deteriorated by the topology evolution. The proposed topology evolution not only provides a reference for the selection and design of the inverter and motor windings,but also reveals the innate character of the CMVF SVPWM.