Control strategy for bi-directional DC/DC converter of a stand-alone wind power system

A novel topology with a bi-directional DC/DC for stand-alone wind power system is adopted, which can maximize the battery life by monitoring and controlling its state of charge(soc) and charge/discharge process. According to the atmospheric conditions, the state of charge of the battery and the load conditions, six possible operation modes of the bi-directional DC/DC are also expounded. This paper proposes a hybrid control strategy with the combination of the PI control and the direct output current control to avoid the voltage surge of the DC bus caused by the mode switching. A 5kW wind power system test bench is developed to verify the effectiveness of the control strategy. The experimental results show that the voltage surge can be limited within 5% and the controller performs well in various wind speed and load conditions.