An Amplitude-Adaption High-Frequency Signal Injection Method for SynRMs at Zero-Low Speed

In this article, an amplitude-adaption high-frequency signal injection (A-HFSI) method is proposed for synchronous reluctance motor (SynRM) sensorless control at zero-low speed to reduce the position estimation error and high-frequency (HF) current magnitude at load condition. Firstly, the conventional high-frequency signal injection (HFSI) scheme is presented. Following this, the influences of cross-saturation inductance on position estimation and the nonlinear characteristics on the high-frequency induced current are examined. Subsequently, an A-HFSI method is introduced, utilizing an enhanced position observation and amplitude-adaptation approach. This method effectively eradicates estimation errors and maintains a consistent HF current magnitude across varying load conditions. Experimental validation of the A-HFSI method is conducted on a 1.5-kW SynRM test bench.