Adaptive Observer Enhanced with Low-Frequency Signal Injection for Sensorless Control of PMSM

This paper presents a method for the sensorless control of permanent magnet synchronous motors, which combines the low-frequency current signal injection strategy having the characteristic of poor dynamic performance with the adaptive observer having poor low-speed performance. In low speed, the low-frequency signal module creates an error signal to adjust the adaptive model of the adaptive observer module. At high speeds, only the adaptive observer works. According to the simulation results shown in the following article, the proposed observer structure has a wide speed range and has both the steady-state accuracy and the great dynamic performance in low speed.