Research On Fuzzy PI ControlStrategy Of Doubly-fed Wind Power System

With the continuous development of human society， energy and environmentalissues facing the world’s increasingly grim. Development of wind poweris verymeaningful to improving the environment and solving energy shortage as wind isanabundant clean energy. Because doubly fed wind power generation system has aseries of advantages，such as wide operating speed range， bi-directional power flow，power converters， low cost， light weight，it has become an international hotresearch scholar，and is currently the most extensive wind power generation system.Because double-fed wind power generation system has a lot of externaldisturbances which parameters is easilyfluctuate， under traditional PI controlstrategy the system’s control performance will be affected. While fuzzy controller onthe parameters of the controlled object is not high，and has excellent anti-disturbanceperformance， but its control precision is poor， and PI control has high precision butit asks system with precise mathematical model. Therefore，in order to improve thesystem’s dynamic response speed and anti-disturbance performance， this papercombined fuzzy control and traditional PI control technology together，using fuzzyrules correcting PI parameters， play their respective advantages.In the system’s network-side PWM converter control strategy study， based on theDC bus voltage， and d， q-axis current changes， fuzzy rules was used to adjust thevoltage loop and current loop proportional， integral parameters， a fuzzy PIcontroller was designed，at the same time， the pre-load current got a feed-forwardcompensation， the rectification grid side PWM converter’s performance is improved，and has a good dynamic characteristics.In order to simplify the mathematical model of the generator，a stator fluxoriented approach was used， the fuzzy control theory is introduced into thedoubly-fed generator’s no-load grid connection control， the rotor’s d， q-axiscurrent and the feedback given change in deviation and the deviation of the currentrate as the input of fuzzy PI controller， using fuzzy rules to adjust PI parameterstimely， simulation results show that the designed controller has a good performanceof dynamic response and adaptability in the no-load grid connection control. Analyzedthe system’s maximum wind power capture theory， after the completion ofgrid-connection， according to the variation of active and reactive power， fuzzy PI controller of the power out-loopand current inner-loopwere designed， the simulationresults show that the designed controller can allowing the system to achieve maximumwind energy tracking and active and reactive power decoupling control， whichachieved an ideal control effect.