Current Source Type PMSG Wind Turbine System with Three-phase Three-switch Buck-type Rectifier for Machine-side Converter

This paper proposes a three-phase three-switch buck-type rectifier converter as a MSC of wind turbine system. Owing to a novel switching modulation scheme eliminating the unwanted diode rectifier mode switching state, the proposed system exhibits the satisfying ac voltage and current waveform quality and torque ripple up to the level of typical current source rectifier even under wide power factor range. The proposed system has been verified through the HILS test on the PMSG wind turbine model of 5MW/4160V. The proposed converter has been shown to provide the stator current THD of 3.9% and torque ripple of 1% under rated power condition. In addition to the inherent advantage of reduced switch count of three-phase three-switch buck-type converter, the proposed switching modulation technique can make this converter a quite viable solution for a MSC placed inside of nacelle, which is under severe volume, weight, and mechanical vibration design limitation.