High Frequency Torque Ripple Suppression for High Frequency Signal Injection Based Sensorless Control of SynRMs

The main limitation for the wide application of synchronous reluctance motors (SynRMs) is the torque ripple caused by the special structures and control method. To lower the cost of SynRM drive system and expand speed range of SynRMs, high frequency signal injection (HFSI) is an effective sensorless control scheme for SynRMs to achieve low and zero speed operation. For the sensorless control, the low frequency torque ripple caused by asymmetric phase currents has been studied by some researchers, however, the high frequency torque ripple and the audible noise produced by it is mostly neglected and needs further investigation. This paper proposes a novel scheme for HFSI method to acquire accurate rotor position information and suppress the high frequency torque ripple caused by high frequency signals at the same time. Applying the special injection scheme, high frequency torque ripple suppression is achieved. The effectiveness of the proposed method is verified in test-bench experiments.