Research on optimal current control strategy for starting phase of five-phase motors

The optimal current control strategy for starting phase of five-phase motors is investigated in view of the short time and large load in the starting phase of the launch vehicle's integrated starter and generator system. First, the optimal injection rate of the third harmonic current is analyzed to reduce the phase current amplitude using the third harmonic current. Derivation of current matching relationship for MTPA control strategy in the fundamental space of five-phase motors to reduce phase current amplitude using reluctance torque. After that, the optimal current control strategy for the starting stage of a five-phase motor is proposed to derive the current matching relation that simultaneously utilizes harmonic currents and reluctance torque. Then, the simulation model is constructed and the optimal current control strategy is simulated and verified, and the phase current amplitude of the proposed control strategy is basically consistent with the theoretical value under the same torque. Finally, experimental verification is carried out on the principle prototype, and the phase current amplitude is reduced from 30.5A to 25.8A with the same load torque of 40 N·m, a reduction of 15.41%. The experimental results are basically consistent with the simulation results, verifying that the proposed strategy is effective.