Comparison of Sensorless Control Methods for Interior Permanent Magnet Motor

This study compares the sliding mode control (SMO) and luenberger observer (LO) methods for sensorless control of interior permanent magnet (IPM) synchronous motors. In the SMO method, a low-pass filter (LPF) is used to minimize the chattering induced by the sign function, but this also introduces phase lag, impacting accuracy. On the other hand, LO eliminates the need for filters to avoid this disadvantage of SMO, but it is more challenging to model as it includes two additional parameters. Additionally, this approach enables extraction of the back electromotive force (EMF) without distortion while reducing chattering. Both SMO and LO use a normalized phase-locked loop (PLL) to accurately predict position and speed. Finally, simulations are conducted using an IPM motor, and the results compare both of the methods.