New Sensorless Control for Interior Permanent Magnet Synchronous Motors of Electric Vehicle

This paper addresses sensorless control of interior permanent magnet synchronous motors (IPMSM). Aiming at the sensor fault of electric vehicle, the sensorless fault-tolerant control technology was supplemented to improve the functional safety. Improved sliding mode observer (SMO) was constructed based on current state equation with the extended back electromotive force (EMF). Through bench calibration, motor parameters in the whole working area were identified and used by the observer adaptively, position estimation offset and system instability caused by the change of parameters were eliminated. The output of switching function was transformed from alpha beta frame to dq frame before low pass filter to avoid fundamental phase delay. In order to improve the dynamic performance of variables estimation, the execution frequency of sliding mode observer and switching function was higher than sampling frequency in DSP. The control method is validated with experimental results that show the effectiveness of the real-time implementation.