Direct Torque Control Speed Ripple Suppression Method for Permanent Magnet Synchronous Motor Based on Load Torque Observation

The space vector modulation-based direct torque control (SVM-DTC) based permanent magnet synchronous motor (PMSM) suffers from large speed ripples due to the periodic fluctuation of load torque. An adaptive load torque feedforward compensation method is proposed based on the observation of the periodic pulsation component in the load torque. The reference torque in the torque loop is compensated according to the torque feedforward. This method can effectively reduce the speed ripples and improve the steady-state performance meanwhile maintaining the advantages of the conventional SVM-DTC. The effectiveness of the proposed method is verified by conducting experiments on the 1.5kW air conditioning compressor.