Speed Sensorless Control based on Stator Currents for PMSG Wind Energy Conversion Systems

This paper proposes a novel speed sensorless control scheme for permanent-magnet synchronous generators (PMSGs) in variable-speed wind energy conversion systems (WECSs), where the rotor angle and speed are extracted by the synchronous reference frame phase-locked loop (SRF-PLL) from the stator currents. Unlike the conventional methods, the proposed control scheme utilizes only one current feedback controller to regulate the generator torque. In addition, the accuracy of rotor angle estimation is not affected by the stator resistance, which varies inevitably during operation. Overall, the proposed sensorless scheme is simple and has less dependency on generator parameters than the conventional methods. Simulation and experimental results have proved the effectiveness of the proposed method.