Research on an Improved Control Strategy for Harmonics Restraint of DFIG System
An improved control strategy for harmonics restraint of doubly fed wind power system is studied in this paper. Considered low order current harmonics (5th, 7th and so on) caused by the distortion or unbalanced grid voltage conditions and the variations of generator itself parameters, an improved control strategy is proposed. In this control strategy, a proportional integral (PI) regulator paralleled with a harmonic resonant (R) controller in the synchronous reference frame is proposed for restraining the stator current harmonics. The control strategy presented in this paper has not effect on the control of fundamental current, and need not the harmonic separation filter and the sequence decomposition in multi reference frames. To verify the effectiveness of this control strategy, simulation model of DFIG system is developed in Matlab/Simulink, and experiments are implemented on the doubly fed experiment platform. The results of both simulations and experiments show that the control strategy proposed in this paper could restrain harmonic currents effectively and it is easy to implement digital control.
Y. F. Meng et al., "Research on an Improved Control Strategy for Harmonics Restraint of DFIG System", Applied Mechanics and Materials, Vols. 130-134, pp. 1338-1343, 2012