Direct power control simultaneously in the rotor side converter and grid side converter of DFIG for wind turbines with elimination of network current harmonics

In this paper, direct power control (DPC) was used for active and reactive power control of DFIG in constant speed reference and variable turbine speed reference based on the optimal power curve. On the other hand, wide application of nonlinear loads in power networks has caused problems such as high current harmonics. Non-linear loads act like harmonic current sources and inject harmonic currents into the supply network. The presence of harmonics in the network causes the harmonic voltage drop and causes other consumers to receive distorted supply voltage, which may cause overheating of power factor correction capacitors, motors, transformers and cables, and mal-operation of some protection devices. Since DFIG is responsible for injection of active and reactive power to the network, it is possible to compensate for the fluctuation of power due to nonlinear loads in the network by proper power injection. Therefore, in this paper, direct power control is implemented to control the power of DFIG, and also to reduce the network current harmonics in the presence of nonlinear loads by using the proper control methods through the rotor side converter and grid side convertors. In this regard, the Matlab/Simulink software is used to simulate a system including a DFIG-based wind power unit and the results are analyzed and compared in different scenarios. The results indicate that accurate and fast control of the DFIG power is along with a significant reduction of network current harmonics.