PR Control for Two-Stage Matrix Converter Excitation Doubly Fed Wind Generation System under Unbalanced Grid Voltage Conditions

This paper presents the analysis and operation of doubly fed induction generator (DFIG) excited by two-stage matrix converter under unbalanced network voltage conditions. Two-stage matrix converter has a real DC link, but does not contain large DC link energy storage capacitors compared with conventional PWM converters. Therefore, output current waveform will be directly affected when the grid side voltage is unbalanced. A new current control scheme, consisting of a proportional resonant (PR) controller, is presented which is implemented in the stationary αβ reference frame and capable of providing precise current control for two-stage matrix converter excitation doubly fed induction generator. Simulation studies are carried out on a DFIG generation system, and simulation results are provided to demonstrate the effectiveness of the proposed control strategy under unbalanced grid voltage conditions.