The Research Of Passive Automatic Maximum Wind Energy Tracking Wind Power Generation System

Off-grid wind generator system output is typically used to charge the battery directly and do not control the wind power conversion part.Since power output characteristics of generator do not match with the maximum power output characteristics of wind turbine,which makes the wind turbine can not always run at the best tip speed ratio when wind speed changes, so wind energy utilization factor is low, generally less than 0.3. According to Bates, the limit theory of wind energy utilization coefficient was 0.593,so if wind turbine always run at the best tip speed ratio, the annual power output can be increased by 20% to 30%.This paper proposes a new off-grid wind turbine generator system which comprises two-winding permanent magnet synchronous generator, controlled saturable reactor, rectifier, battery and load. The generator contains two sets of winding named winding 1 and winding 2.The number of turns of winding 1 is more than that of winding 2,so at a low speed only winding 1 outputs power, while at higher speed, both winding 1 and winding 2 output power. The output power curve of the new system is approximately coincident with the maximum output power curve of wind turbine, which makes wind turbine run at the best tip speed ratio automatically.Based on assumptions,the design method has be proposed,and a 300W prototype has be produced.Simulation and experiment show that the new system can make wind energy utilization coefficient rise sharply.