Unified coordinated control strategy for two parallel inverters TPOW-PMSM system

Abstract

The three-phase open-winding permanent magnet synchronous motor (TPOW-PMSM) is generally used to drive electric vehicles. The voltage vector spatial distribution and fault-tolerant topological structure of a TPOW-PMSM system with two parallel inverters are analyzed in this paper. Then, based on the unified PWM modulation algorithm, a unified coordinated control strategy based on reference voltage vector 120º decoupling control is proposed. The speed and current double closedloop control systems of two parallel inverters are designed, and a PI + repetitive controller of the speed loop is designed to realize fast and stable speed control. The realization process does not require sector judgment or table lookup calculations, and the switching time of each bridge arm switch tube is determined by the instantaneous value of the three-phase voltage of the two parallel inverters, which simplifies the control algorithm. Experimental results show that the unified coordinated control strategy with the PI + repetitive controller can control the normal operation of a TPOW-PMSM, and realize smooth and reliable transitions from the normal operation state to the fault-tolerant operation state. The proposed unified coordinated control strategy with the PI + repetitive controller effectively suppresses the instantaneous value of system zero-sequence current, and inhibits the influence of the dead zone effect.