Current Zero-Crossing Duration Reduction of a Semicontrolled Open-Winding PMSG System Based on Third Harmonic Current Injection

The open-winding permanent-magnet synchronous generator (PMSG) fed by a semicontrolled converter is a promising configuration due to lower expense, simplified driving circuit, and reliable operation capability. When supplied by a common dc bus, the open-winding PMSG system can be more simplified. Because the voltage output by the diode converter is decided by the three-phase current polarity, the available voltage vector modulation range of the voltage source converter is limited. As a result, the current zero-crossing duration behavior is determined by the power factor angle, which will lead to zero-crossing voltage pulse disturbance, serious electromagnetic interference, and unexpected diode switching loss. This paper aims to reduce the current zero-crossing duration by injecting the third harmonic current into the zero-sequence current. A proportional resonant regulator is proposed to control the zero-sequence current. Finally, the proposed method is validated in a 1-kW semicontrolled open-winding PMSG experimental system.