Current Harmonics Injection Method for Simultaneous Torque and Radial Force Ripple Mitigation to Reduce Acoustic Noise and Vibration in SRMs

Switched Reluctance Machines (SRMs) have high torque and radial force ripples compared to other type electric machines resulting in more acoustic noise and vibration. This paper introduces a new control method to reduce both the torque and radial force ripples as well as the specific harmonics of the radial force generation to minimize the acoustic noise and vibration in SRMs. The proposed method achieves these three objectives by injecting harmonics to the motor phase currents. The harmonic numbers of the phase currents to be injected are studied in detail in achieving the objectives. The magnitude and the phase of the injected currents are optimized globally through the multi-objective optimizations run iteratively during control design stage. Finite Element Analysis is performed to develop dynamic simulation of the SRM and implement the optimization to generate the current waveforms for various operating conditions. The current waveforms are applied to FEA models to predict the torque ripple and the acoustics noise through Multiphysics simulation packages. The final FEA simulations demonstrated that the proposed control method reduces the acoustic noise by 26.44 dBA, peak to peak torque ripple by 67% while achieving similar torque density compared with the conventionally controlled SRMs.