Space Vector PWM for Six-Phase Motor under Inverter Single-Leg Open-Circuit Fault

Abstract

A six-phase dual-Y shift-30° motor will be in poor operation after a fault of single-leg open-circuit occurs to a sixleg two-level inverter. To improve the operation performance of the motor, a method of space vector pulse width modulation (SVPWM) with fault-tolerance is proposed. The winding terminal connected to the bad leg is connected to the DC-link mid-point of the inverter. Then the motor fed by the five-leg inverter can get 32 stator winding voltage states, corresponding to 32 basic vectors which are all zero vectors in the 01-02 plane. With the 32 basic vectors, by using an optimal model four intermediate vectors are constructed which are all zero vectors in the $z_{1^{-}}z_{2}$ plane. The four intermediate vectors and some equivalent null vectors are used for synthesis to make the synthesized result track a desired vector. Experimental results show that the stator currents, electromagnetic torque and rotor speed of the proposed method are better than those of the sixphase SVPWM without fault-tolerance.