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, the selection of the phase and amplitude of the harmonic current based on vibration and noise has been explored in this paper. 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. After incorporating the harmonic suppression control loop into the operational prototype, the harmonic content is conspicuously reduced, and the amplitude of the torque ripple is decreased by 50% while the average torque remains essentially unaltered. The improvement spans from 5 to 10 dB within the range from 1400 rpm to 1900 rpm, and from 1 to 5 dB within the range from 1000 rpm to 1250 rpm.