Research Of Control Strategies In Wind Power System Based On SCIG Full-power Converter

With serious energy crisis and environmental concern, to develop clean energysources has become the theme of the contemporary world. Wind power technology hasbecome the research focus of all countries along with the wind energy developed andutilized rapidly. In this paper，the control method of wind power system with full-powerconverter based on squirrel-cage induction generator is stuidied in depth.The simulationresults show that the proposed operation control strategies are effective which have certainreference value in relative fields to research.There are complete works in this paper:(1) The several current wind power systems are introduced. It is analyzed themathematic model of the wind turbine, SCIG and the three phase iverter. Besides, thedesign of PI parameters is analysed when the three phase inverter is controlled.(2) The generator side converter is used a speed-sensorless direct torque controlstrategy, and a indirect vector control strategy is analyzed also. The grid side converter isused the network voltage oriented control with voltage and current dual close-loop strategy.And it is analysed the impact of the wind power system during the symmetrical voltagedips simply. To improve the LVRT of SCIG, this paper is used a unloading circuit to theDC-side and the grid side conveter run at STATCOM mode.(3) The simulation platform of the SCIG wind power system is based on Matlab/Si-muink. The simulation results show that by using speed-sensorless direct torque controlmethod, the generator side converter can adjust generator rotational speed quickly to meetthe dynamic responses of the wind turbine requirement. The grid side converter couldachieve the active and reactive power control independently, which also could stabilizevoltage. Its capability of LVRT can be improved by shedding loads during the voltage sagperiod.