An improved adaptive observer for permanent magnet synchronous motor

This paper studies a speed sensorless permanent magnet synchronous motor (PMSM) drive system based on the adaptive observer method, analyzes the problem of instability in the low-speed electric mode according to the observer linearization method. To solve this problem, the observer augmented with a signal injection technique is researched. The simulation results show that the method is effective to enhance the system parameter robustness and speed observation precision, improve low speed performance of the speed sensorless vector control system.