A New β-axis Based High-Frequency Signal Injection Model for Low-Speed Sensorless IPMSM Drives

This paper presents a high frequency linear model for low-speed sensorless control of interior permanent magnet synchronous motor (IPMSM) drives. The proposed model uses a β-axis high frequency signal injection in order to model a new high frequency flux variable, which has similar properties to the standard electromotive force (EMF) used for high-speed sensorless control. Through the proposed model, the well established observer techniques from the literature can be used for rotor position and speed estimation. Thus, the low-speed sensorless scheme can be designed in similar form as the high-speed EMF based methods. Here, position and speed estimation are performed by an adaptive full-order observer, which is designed through a pole placement method and its stability constraints are investigated. Simulation results validate the proposed high frequency linear model and adaptive observer design method under sensorless vector control.