Comparative Study of Direct Power Control with Vector Control for Rotor Side Converter of DFIG

Abstract

This paper presents the implementation of direct power control(DPC) for the rotor side converter of doubly-fed induction generator(DFIG) connected to the wind generation system, as an alternative to the classical vector control(VC). In this paper, DPC is based on space voltage vector and the active and reactive power controllers. SVM (Space Vector Modulation) is applied to compose fixed-switching-frequency DPC strategy, which replaces the lookup-table method in conventional DPC. DFIG's mathematic model and the two control strategies are given, and the simulations of DFIG based on DPC and VC are made separately by MATLAB/Simulink. The control performance of the two control strategies are discussed based on the simulation work. And the differences of them are compared on the aspects of steady, dynamic and transient characteristics. This study makes a detailed analysis and provides evidence to the research of DFIG's control system. It sets up the foundation for the research of the DFIG's short circuit characteristics as well as the related protection configuration. And some useful suggestions about the selection of these two control strategies under different conditions are provided. (6 pages)