Study On Intelligent Grid-connected Controller For Offshore Wind Power System

Since one-time energy brings the environment problems and the energy crisis,new energy becomes the focus of study. As a kind of new energy with advantages offree from contamination, easy to collect, and inexhaustible, etc, wind energy attractsmuch attention. Compared with land wind, offshore wind power has more content,better quality and doesn’t take the limited land resources. So offshore wind powergeneration becomes trend of development. Grid-connected is the key of wind powerto be used fully. Inverter is the main converter equipment to realize grid-connected.This paper focuses on the study on grid-connected inverter for offshore wind powergeneration.Firstly, topological structure of various wind power generators is discussed.This paper chooses direct driving type permanent magnet synchronous generator asthe research object. Operating principle of the wind power generator which hasrated power of1.5MW is analyzed and mathematical model is established. Thecontrol strategy with variable pitch variable speed and constant frequency isproposed.Secondly, the defects of traditional Z-source inverter are analyzed. Consideringthe particularity of offshore wind power generation, this paper puts forward anoffshore wind power system applying the improved Z-source inverter forgrid-connected control. The operating principle is analyzed. The Z-source networkcircle parameters are designed. Through improvement, the sinusoidal pulse widthmodulation(SPWM) and space vector Pulse width modulation(SVPWM) twomodulation strategies are used to control improved Z-source inverter. Many ways ofinserting shoot-through zero vectors are researched respectively. Then thesimulation model build in Matlab realizes the function of boost and inversion.Finally, the mathematical model of improved Z-source inverter grid-connectedis established. Combined with the requirements of the inverter grid-connected, akind of double closed-loop control strategy with capacitor voltage outer ring andgird-connected current inner ring is proposed. The improved Z-source inverter unitpower factor grid-connected is realized in the simulation model.