A novel topology for improved DC bus utilization in PMSG based wind energy generation system

The permanent magnet synchronous generation (PMSG) systems are more popular for low and medium power wind generation applications. Since power converters used in the PMSG systems has a drawback like poorer DC bus utilization of a conventional inverter at lower wind speeds restrict the lower energy generation region. The lower limit of the generation system defined by rating, topology and PWM techniques used for the converters. In this work a new dual two level inverter based topology is proposed for the grid side converter for more DC bus utilization. This would not only extend the system lower limit to feed energy to the grid at lower wind speeds but also LVRT capability of the system. The two inverters in the proposed system interfaced to grid through a three phase transformer that inherently provide isolation between generation system and external power network. The new zero sequence voltage elimination PWM (ZSVEPWM) technique is developed for proposed configuration to eliminate the zero sequence voltages (ZSV). The complete elimination of ZSV facilitate to use common DC link. The efficacy of proposed converter with the ZSVEPWM to improve the overall operating range of PMSG based wind system is substantiated with the MATLAB simulations.