Output control of a wind power generating system with a battery load by fuzzy control

Abstract

In this paper, concerning wind power generating system in which batteries are connected to D.C. generator for load, development of control method and investigation on output characteristic by simulation were carried out. This control method is possible to take out wind energy effectively, using fuzzy reasoning by measurement of wind speed and windmill speed. Firstly, the stationary characteristics of the system were investigated in order to decide membership function. The windmill speed at stationary condition and batteries voltage which gives output (of generator) maximum were decided according to the windmill speed which is divided 5 classes according to struggle. Fuzzy rules were experiential decided as follows ; when there is a windmill speed to an acceleration state, windmill seed takes priority to control rules. On the contrary, when there is a windmill speed to slowdown state, wind speed takes it. As the results of investigation, effectiveness of output control by fuzzy reasining was confirmed for both cases of wind speed is fluctuating sinusoidally or for natural wind or wind speed is varying like natural wind. Especially, at the time of fluctuating wind speed, when frequency of wind speed becomes lower, effectiveness of output control becomes larger. In addition, for natural wind which was measured practically, it was made clear that larger energy generation is possible by practicing output control compared to constant load battery voltage.