The Investigation of Multiphase Motor Fault Control Strategies for Electric Vehicle Application

Multiphase motors have the advantages of high power at low voltage, small torque ripple, high efficiency, and anti-interference operation at fault condition. The machines are especially suitable for the electric vehicle (EV) applications. In this paper, the five-phase induction motor is selected as an example. The fault-tolerant control strategies for different optimization objectives are proposed. For single-phase fault and two-phase fault, according to different constraints, the current amplitude equality method, the minimum stator copper loss method, the minimum torque ripple method is compared and analyzed. Considering that the fundamental and harmonic magnetic field are no longer decoupled after the fault, the problem of magnetic field coupling after the phase missing of the multiphase motor is analyzed in detail. Then, a method to suppress the coupling of spatial magnetic field is proposed, and the torque ripple is reduced from 23.53 to 3.55%. Finally, the effectiveness of the fault-tolerant control strategies are verified through the experimental comparison.