Maximum output power control system of variable-speed small wind generators

This paper proposes a maximum output power control system for variable-speed small wind generators. The proposed control system adjusts the rotational speed of a single-phase AC generator to the optimum rotational speed, which yields the maximum output power according to the natural wind speed. Since this adjustment is performed on-line in order to adapt to variations in wind speed, the rotational speed of the single-phase AC generator is adjusted by controlling the generated current flowing in an FET (field-effect transistor) device, serving as the generated power brake, which is linked directly to the single-phase AC generator. In order to reduce heat loss from the FET device, a PWM (pulse width modulation) controller is introduced. An experimental model of the proposed control system was built and tested, and the validity and practicality of the proposed control system were confirmed by the experimental results.