Comparative study on current and voltage controlled voltage source converter based variable speed wind generator

Different structure and control algorithm can be used for control of power converter. One of the most common control techniques is decouple proportionate integral (PI) control of output active and reactive power to improve dynamic behavior of wind turbine. In this paper, a new current controlled voltage source converter (CC-VSC) scheme is proposed to control both the rotor and grid side converters of DFIG. The performance is verified by comparing the results with voltage controlled voltage source converter (VC-VSC) scheme. The earlier scheme offers the advantage of reduction of the number of PI controllers used in the rotor side converter without degrading dynamic and transient performances. Moreover, DC-link protection scheme can be omitted using the proposed CC-VSC based DFIG control, which reduces overall cost of the system. Simulation analysis by using PSCAD/EMTDC is carried out to find out the effectiveness of the proposed CC-VSC based control scheme of DFIG over the VC-VSC based control scheme.