Sensorless Control of Permanent Magnet Synchronous Motor Based on New Integral Sliding Mode Observer

In order to solve the problem of vibration shaking in the sliding mode observer (SMO), a new integral SMO is proposed in this paper, and conventional discontinuous switching function is replaced by smooth hyperbolic tangent functions, which eliminates the low-pass filter. The stability of the SMO is analyzed by Lyapunov stability criterion. Then, the influence of boundary layer (BL) size on SMO back-EMF is analyzed, and the optimal boundary layer size is determined. In addition, using the phase-locked loop (PLL) in the rotating coordinate system instead of the PLL in the stationary coordinate system has higher dynamic performance, shorter response time, and can eliminate the influence of the oscillating component in the PLL. Lastly, the practicability and availability of the containment strategy presented in this paper are validated by comparing the waveforms of estimated current, estimated speed and estimated position between the conventional scheme and the presented scheme.