Carrier signal injection based sensorless control methods for IPM synchronous machine drives

This paper presents a comparison of carrier signal injection methods for sensorless torque and motion control of interior permanent magnet synchronous machine (IPMSM) drives. Rotor position can be identified at standstill and higher speeds by using one of two spatial saliency based high frequency carrier signal injection methods: rotating vector in the stationary frame or pulsating vector in the estimated rotor frame. Carrier currents for both rotating and pulsating voltage carrier injection are derived by using an IPMSM model for high frequency. An appropriate carrier signal extraction and a spatial saliency tracking scheme for both injection methods are developed for robust sensorless control. By interfering with the spatial saliency, saturation-induced saliencies act as disturbances to the rotor position estimation. Modeling, measurement, and analysis of the undesirable saturation-induced saliencies are presented for both carrier signal injection methods.