Sensorless Control of PMSM Using Series Leading Corrected Linear Extended State Observer

The conventional linear extended state observer (LESO) exhibits low-pass filtering characteristics, which can lead to phase lag in the estimated back electromotive force (BEMF) during sensorless drive of permanent magnet synchronous motors (PMSMs). At the same time, excessively increasing the LESO bandwidth to reduce estimation errors can lead to system oscillations and introduce high-frequency noise interference. To address the issue, a LESO based on a series lead corrected network (SLC-LESO) is proposed. The module consists of the traditional LESO and the transfer function of the series lead correction network. By adjusting the parameters of the series lead corrected network and reasonably matching the bandwidth of LESO, phase lag in the BEMFs estimated by LESO can be corrected. It ensures that the steady-state rotor position estimation error does not exceed 6.5 degrees across the rotor electrical speed range of 150 to 1300 rad/s. Finally, a comparative experiment was conducted on a 400W PMSM test bench, and the results validate the effectiveness of the proposed method, with an overall 5% improvement in observation performance.