Restart Strategy for Sensorless PMSM Drive with Single Zero Voltage Vector in Railway Application

This paper proposes a control algorithm and a restart method for permanent magnet synchronous motors without position sensors in railway application. The method combines a Luenberger observer and a sensorless observation method based on PLL, allowing for accurate observation of rotor position and speed within the high-speed range of the motor. Additionally, the method utilizes the setting of the contactor to estimate the initial position and speed during the restart process using the current generated by a single zero voltage vector, enabling precise estimation of the motor's speed and position in the flux-weakening region. The effectiveness of the proposed algorithm is demonstrated through simulation.