Direct Drive Wind Energy Generation System Based On Buck-Boost Matrix Converter

With the deterioration of the human enviroment and growing shortage of global fossilenergy,countries all over the world pay more attention to renewable energy sources.Windenergy as renewable energy has many advantages,for example,wide of distribution range,richreserves,huge developing potential,large-scale use and so on.It has become the importantresource in every country of the world.The direct drive permanent magnet wind power systemhas become the main stream research because that the permanent magnet synchronousgenerator rotor is directly connected with wind turbine without growth gearbox,highefficiency,small impact on the grid and the advantage of low voltage ride through.Buck-Boost matrix converter(BBMC) not only possesses the advantage of adjustableinput power factor,sinusoidal input current,four-quadrant operation,bi-direction powerflow,but also have other advantages,such as,its voltage transfer ratio can be greater or lesserthan1,the modulation of output voltage and frequency can be adjusted,output sinusodal inputcurrent without LC filter,low harmonic content,without a filter capacitor in direct current link.Auto-disturbance-rejection control(ADRC) was applied to BBMC system in this paper,forreducing harmonic content,improving quality of output waveform and improving robustnessof system,then the BBMC is used as power converter for the direct drive permannent magnetwind power system.In this paper,the structural features and working principle of BBMC is introduced,and thecontrol strategies of BBMC,which includes sliding mode control,discrete sliding mode controland double-loop control strategy, are analyzed.The ADRC of BBMC system is built by usinginductor current and capacitor voltage as state variable,then the fundamental and designprocedures of ADRC is futher discussed.Next the working principle and running characteristicof wind turbine and permanent magnet synchronous generator are analyzed.And,themathematical model of wind turbine,permanent magnet synchronous generator and BBMCare built,for tracking the maximum wind energy source.The double closed loop controlstrategy is used in BBMC,which is composed of inner current loop and outer power loop,andcombine space vector pulse width modulation(SVPWM)technology.The simulation analysisdemonstrates the validity of the proposed method and the feasibility of the control strategy.At last,the prototype of BBMC is constructed.The DSP chip TMS320F2812was used asthe controler,and MOSFET as power switches.And,the experimental software is developed.Experimental results verify the validity and superiority of its control method andengineering design.