Three-stage static power converter for battery charging feasible to small wind energy conversion systems

This paper presents the analysis, design, simulation, and experimental results for a three-stage static power converter for battery charging feasible to small wind energy conversion systems (SWECS). The system employs a boost converter cascaded with a Graetz bridge, what allows the implementation of a Maximum Power Point Tracker (MPPT) and the reduction of the mechanical speed under overvoltage conditions across the batteries. Besides, a buck converter is connected in series with the boost stage to ensure a constant voltage bus between the aforementioned topologies. Thus, it is possible to extract the maximum power over the entire wind speed range, and battery charging can be realized through conventional techniques. The complete design of the proposed battery charger including power, control, and supervisory circuits are presented and developed, considering a 300 W system, with the possibility of charging battery banks rated at 12 V or 24 V. Simulation results are presented to prove the existence of maximum power points in the wind generator. Finally, the experimental results of the developed prototype required to validate the functionality of the proposed study are presented and discussed.