Parameter Estimation for Sensorless Position Control of PMSM Drives with Long Cables in Subsea Applications

There is an increasing interest in powering the subsea loads, such as subsea motor drives, from renewable energy sources, either from the shore or offshore. Due to the long distance from the motor controller to the motor, the use of sensor cables causes electromagnetic interference (EMI) and noise problems in the position information signals. Hence, the sensorless operation of subsea drives becomes important. In addition, variations in system parameters due to changes in operating conditions can result in the deterioration of the performance of drives, and may even lead to unstable operations. In this paper, a closed-loop observer-based method is proposed for estimating the speed and inductances of the equivalent system, which includes a transformer, cable, and motor inductances. The proposed estimation scheme is validated using MATLAB(2020a)/Simulink and Typhoon hardware-in-the-loop for a 500 kW, 4.2 kV interior permanent magnet synchronous motor (IPMSM).