Battery charger with MPPT function for stand-alone wind turbines

In this paper, a buck-type power converter as the battery charger for the stand-alone wind turbine is proposed. The proposed power converter can harvest the maximum power from the wind turbine while generating pulsating current for the battery bank to improve the charging efficiency. The maximum power point tracking (MPPT) function is realized by the circuit parameter design of the power converter and the characteristics of wind turbine. The pulsating battery charging current is implemented by the discontinuous conduction mode (DCM) operation of the proposed power converter with constant on-time control. Also, the over-speed protection of the wind turbine can be naturally achieved when high power output occurs. Simplicity is one of the major advantages of the proposed power converter. Hardware experimental results from a 400 W prototype circuit are presented to verify the performance of the proposed power converter.