A Novel Sensorless Unity Power Factor Control Method for Six-phase PMSG in Direct Drive Wind Energy Conversion Systems

In the high power direct drive wind energy conversion systems, the power factors of both the generator-side converter and the grid-side converter are controlled to one in order to make full use of the capability of the power converters. In this paper, a novel sensorless unity power factor control method based on the reference coordinate system rotating synchronously with the voltage of the generator-side converter is proposed to estimate the rotor speed of the six-phase PMSG. This method is very simple and only needs the measurement of the voltage phase of the generator-side converter. The power factor of the generator-side converter can be controlled to one easily and it can increase the capability of the converter. Simulation and experimental results verify the analysis and the conclusion.