Current Ripple Sampling based Angle Error Compensation for High-speed Permanent Magnet Synchronous Motor Sensorless Control Considering Inductance Saturation

Online parameter identification of high-speed permanent magnet synchronous machine (HSPMSM) has been studied extensively neglecting magnetic saturation. However, at heavy load condition, the difference between apparent inductance and incremental inductance generally exists, which will introduce a potential error in rotor position estimation for sensorless control. Unfortunately, previous research on HSPMSMs has not sufficiently investigated the angle error caused by this saturation. To address this issue, the influence of inductance mismatch on rotor position estimation is analyzed where the inductance error is found proportional to the estimated rotor position error. This analysis provides a potential conversion from apparent inductance identification, which is based on integral armature flux linkage, to a simpler non-integral angle error estimation. Consequently, a current-ripple-sampling (CRS) based highly sensitive angle error model is proposed in stationary frame. This method leverages the phase information of the current to enhance sensitivity to rotor position errors. Furthermore, compensation methods are developed to directly offset the angle error or identify the apparent inductance, thereby mitigating its impact. Experimental results validate the effectiveness of the proposed methods, both in mildly and heavily saturated cases.