Simultaneous Sensorless Rotor Position and Torque Estimation for IPMSM at Standstill and Low Speed Based on High-Frequency Square Wave Voltage Injection

In this article, a method of simultaneous sensorless rotor position and torque estimation is proposed for interior permanent magnet synchronous machines at standstill and low speed. The proposed method estimates the torque using high-frequency inductances identified from the current variations due to high-frequency square wave voltage injections in the estimated
dq
-axes, which are simultaneously used for sensorless rotor position estimation. The proposed method is not dependent on the fundamental model and has taken the cross-coupling effect into consideration, allowing for low cost and fast torque estimation at standstill and low speed. Both simulations and experiments are carried out to verify the effectiveness of the proposed method.