DSP-based control of sensorless IPMSM drives for wide-speed-range operation

A position sensorless control strategy of an interior permanent magnet synchronous motor (IPMSM) drive based on a digital signal processor (DSP) is proposed. To achieve sensorless wide-speed-range operation, a hybrid position estimation strategy combining the high frequency (HF) signal injection method with the electromotive force (EMF)-based method is presented. At low-speed range, an HF voltage signal is injected, and a rotor position observer is designed to improve the robustness to the load disturbance. At middle- and high-speed ranges, a sliding-mode observer based on the extended EMF of IPMSM is designed for sensorless operation. Moreover, during the switch-over area, the two position estimation methods are both enabled for the sensorless control. A software phase-locked loop and a dead-time compensation strategy are adopted to improve the position estimation accuracy. The experimental results demonstrate the feasibility of the control strategy with a sensorless IPMSM drive based on a DSP.