Sensorless Control of PMSG Wind Power Systems Based on ROGI-FLL

In this paper, a novel sensorless control scheme using the reduced-order generalized integrator (ROGI)-frequency-locked loop (FLL) for the permanent magnet synchronous generator (PMSG) wind turbine systems is proposed. Through analyzing the transfer functions, it is confirmed that the ROGI-FLL can behave like the frequency-adaptive integrators. Therefore, if the rotor back-EMFs found from the PMSG model are regarded as the ROGI inputs, the estimated rotor flux linkages can be considered as the ROGI outputs. Then, the rotor position and rotor speed can be estimated based on those rotor flux linkages. With the good harmonic rejection capability of ROGI, the proposed rotor flux estimation becomes robust against the measurement noises. Furthermore, it is not faced with the saturation in the case of the DC offset existed in the rotor back-EMFs. Through the simulation results, it is confirmed that despite the simplicity of the ROGI, the proposed sensorless control method can provide a similar performance to that using the existing dual SOGI-FLL-based sensorless control method.