Study Of Sensorless Drive For Permanent Magnet Synchronous Motor Based On High Frequency Signal Injection

Permanent magnet synchronous motors (PMSM) have been widely used as AC drives due to their high efficiency, high power density and no excitation current, but the accurate rotor position and velocity are needed in High-performance PMSM vector control system to realize field orientation. Rotor position and velocity are acquired traditionally through mechanical sensors, these sensors are expensive, less reliability and not easy to be maintained. So, the sensorless drive of PMSM has become a hotspot of PMSM control. Although lots of research results appeared, most of them are based on fundamental machine equations, which limits the low speed and zero speed operation, and are sensitive to the machine parameters with bad robustness. To solve these problems, the method of high frequency signal injection to estimate rotor position and velocity are used in this paper.First, three basic structures of PMSM are introduced. PMSM vector control based on PMSM model is illustrated and the present sensorless control methods are discussed. Second, there are two kinds of high frequency signal injection method, rotating high frequency signal injection and fluctuating high frequency signal injection. The ways to extract rotor position of these two methods are analyzed and demonstrate their feasibility and validity with tools of MATLAB/SIMULINK. Finally, the fluctuating high frequency signal injection method is proved successfully on PMSM sensorless vector control based on the DSP chip TMS320F2812 of TI. The experimental results prove that this sensorless control can realize the low speed operation of machine and has less sensitivity to the variation of machine parameters.