Sensorless IPMSM position control system using a high frequency injection method

This paper proposes a sensorless IPMSM position control system based on a high frequency injection method. The proposed method uses 12-bit low resolution A/D converters to covert the stator currents of the IPMSM. In addition, a 0.67kHz injection voltage, which has a 30 V amplitude, is used. By measuring the stator currents, the injection current components related to the injection voltage can be obtained. Then an estimation method is proposed to obtain the estimated rotor position. After that, a compensation algorithm related to the saturation of the mutual inductance is implemented to reduce the rotor position estimation margin of error. Finally, a closed-loop system based on the high frequency injection method is implemented. Measured results show the proposed method can achieve satisfactory performance with a margin of error of only ±4 degree.