Comparison of Sensorless Control Methods of PMSM Ship Propulsion Drives

Permanent magnet synchronous machines (PMSMs) play a major role in large electric transportation such as electric ships. This is due to its high efficiency and high torque density. For these large propulsion drive applications, high quality sensorless control is preferred since the reliability and safety are important considerations. In this paper the methods and performances of different observers for sensorless control of large ship-propulsion PMSM drives are compared. The observers are compared with each other to provide insightful information for the purpose of selecting the most suitable observer technique for implementation in PMSM ship propulsion. In this regard the sliding mode observer (SMO), the model reference adaptive system (MRAS) observer, the Luenberger observer and the Extended Kalman Filter (EKF) are applied for sensorless control. The MATLAB-simulation results of these observers for a 4-MW ship-propulsion PMSM are provided. The results show that the SMO has excellent dynamic performance compared to the other observers at both low and high machine speeds.