Research on motor Harmonic injection control in Hybrid System to Suppress the Torsional Vibration

Based on the harmonic current injection method used to suppress the torsional vibration of the electric drive system in this paper, and the exploration of the selection of the phase and amplitude of the harmonic current based on vibration and noise. Through the adoption of the active harmonic current injection method, additional torque fluctuations are generated by actively injecting harmonic currents of specific amplitudes and phases, and closed-loop control is carried out to counteract the torque fluctuations of the motor body. The selection of the magnitude of the injected harmonic current is crucial and plays a vital role in the reduction of torque ripple. Incorrect harmonic currents may not achieve the optimal torque ripple suppression effect or even increase the motor torque ripple. Since the actively injected harmonic current is used to counteract the torque ripple caused by the magnetic flux linkage harmonics of the motor body, the target harmonic current command is very important, and the phase and amplitude of the harmonic current are set according to the following method. The phase and amplitude of the 5th harmonic current need to be selected. The amplitude of the 5th harmonic current involved in this paper is all based on the amplitude of the fundamental current as the reference object, and the phase of the 5th harmonic current is all based on the phase of the fundamental current as the reference object. To sum up, when a 5th harmonic current with an amplitude of 14% of the fundamental amplitude and a phase leading the phase of the fundamental current by 150 is injected into the three-phase current of the motor in this paper, the noise can be weakened better, and the weakening amplitude can reach 80%. The method for the phase and amplitude of the 7th harmonic current is the same as that of the 5th harmonic current.