Study on Grid-Connected Converter for Permanent Magnet Direct-Driven Wind Power System

Abstract

According to characteristics of unidirectional flow of energy in permanent magnet wind power system, the paper proposes a two-quadrant three-level converter topology. Combined with method of the optimum tip speed ratio for tracking the maximum wind energy, the generator-side converter uses the double closed-loop control, speed outer loop and stator current inner loop control, whose control objective is to track the given generator speed. Grid-side converter uses the direct power control strategy based on virtual flux-linkage orientation. On the basis of MATLAB simulation platform, the permanent magnet wind power system simulation model was established. The simulation results show that the grid- and generator-side converter can operate with unity power factor, furthermore, verifies that the proposed converter structure is feasible.