The Study Of The DFIG High Performance Control Under The Actual Grid Environment

With the outstanding of the environmental pollution, and the exhausting of the fossil energy, as a pollution-free and renewable energy, the wind energy is booming nowadays. The main way for the wind power utilization is the Wind Power Generation. The capacity of the connected wind power generation has arised from kW to MW and even kMW, which means the coeffection between the large wind power generator and grid cannot be overlook. So the study of the wind power turbine control has to put on the agenda, and the focus of its control shifted from the ideal grid to the real grid. As a main type of the wind power generator, the Double-Fed Iduction Generator (DFIG) is especially sensitive to the grid because its stator is connect to the grid directly and its rotor connector to the grid through a back-to-back convertor. Based on the real grid situlation, this paper studied the enhenced control strategy of the DFIG under real grid situlation.This paper studied the Grid Side Convertor (GSC) and the Machine Side Convertor (MSC) of the DFIG control strategy while the grid voltage contain Negative sequence and harmonic component. Firstly, the mathmatical model of DFIG is built in static3-phase coordinates under this grid condition, and through coordinates transform, this model shifted to the synchronous, reverse synchronous, reverse5and7times synchronous reference frame. Then, Figure out the apparent power of the DFIG, analysis the control objectives of the GSC and MSC.After the seperater study of the DFIG control strategy when the grid contain Negative sequence and harmonic voltage, in consideration of the real condition is that the grid contain the Negative sequence and harmonic voltage at the same time, so this paper do a further study on the DFIG control strategy.Based on the PSCAD/EMTDC simulation platform, the study complated step-by-step. Firstly, the separate mathmatical model of the GSC and MSC is built under every grid condition, and simulate the each control strategy seperately. Then, a integrated DFIG model is built to simulate the control strategy.