The proposed turbine system consists of a PMSG and a three phase voltage-doubling rectifier using passive elements only. Automatically，this rectifier operates in double voltage mode in low wind velocity，and operates in bridge mode in high wind velocity. Therefore，the proposed generator system can obtain the maximum power output of wind turbines in a large velocity region without using the control circuit. In this paper，we propose a way to improve wind generator’s efficiency for the control-circuit-less method. The effectiveness of the proposed method is demonstrated with experiment.
