Open-End Nine-Leg Half-Controlled Converter for Six-Phase Synchronous Generator-Based Wind Energy Conversion Systems

This paper presents a unidirectional converter for wind energy conversion systems (WECS) based on six-phase synchronous generators. The proposed configuration uses three two-level three-phase half-controlled converters, nine legs in total, connected in series with the generator stator windings, in an open-end winding configuration (OEW). Half-controlled converters are composed of three controlled switches and three non-controlled switches, reducing the overall cost of the system. The converters operating principles, pulse-width modulation (PWM), and generator control are discussed. Furthermore, the proposed system is compared with conventional configurations concerning harmonic distortion and semiconductor losses. Simulation and experimental results show the validity of the discussed strategies. Finally, it was verified that the proposed system maintains low-distorted currents over the generator stator windings, despite the uncontrolled switches.