Simulation and Experimental Studies of Speed Sensorless Control of Permanent Magnet Synchronous Motors for Mine Electric Locomotive Drive

This paper presents a novel sensorless control method of permanent magnet synchronous motors at standstill and low speed based on a low-frequency current signal injection. The approach superimposes a persistent LF current signal into the estimated d-axis to get the rotor position error angle-related signal by detecting the corresponding voltage response and current response. Then the rotor position and motor speed are obtained. Theoretical analysis and simulation results demonstrate that the approach can achieve sensorless control of permanent magnet synchronous motors at zero and low speed, ensure good dynamic and static performances, and achieve effective control when applied to servo system. Finally, a test prototype system which used a digital signal processor and space vector pulse width modulation technology has been developed. Experimental results show that the system has better static, the effectiveness and dynamic performance of the adaptive test signals in a sensorless controlled surface-mounted permanent magnet synchronous machines.