A second-order generalized integrator-linear extended state observer for sensorless control of permanent magnet synchronous motor

The high-frequency (HF) signal injection method is widely used in sensorless control of permanent magnet synchronous motors (PMSMs). Conventional strategies typically integrate a band-pass filter (BPF) with a phase-locked loop (PLL) to extract HF current responses and estimate rotor position. However, this approach introduces significant phase delay, restricts system bandwidth, and exhibits poor robustness against disturbances. To overcome these limitations, a strategy that integrates a second-order generalized integrator (SGI) with a linear extended state observer (LESO) was proposed. The SGI enables rapid demodulation of the HF current response with negligible phase lag, while the third-order LESO provides strong disturbance rejection by estimating and compensating for total system uncertainties in real time. The validity of the proposed sensorless control strategy has been demonstrated through simulations and experimental tests. Simulation and experimental results show that the SGI-LESO significantly reduces position-estimation error, improves disturbance rejection, and ensures smoother start and dynamic speed tracking.