A Study of Wind Power Inverter Operating in Grid-Connected and Stand-Alone Mode

Abstract

Wind turbine system (WTS) is a representative distributed power generation (DG). Establishment of WTS model and control strategies is of important practical significance. One critical field is the research of inverter system. It should be operated in stand-alone (SA) or grid-connected (GC) mode. The purpose of this thesis is to establish simulation platform of WTS inverter control model in Matlab/Simulink environment, which includes two typical DG control strategies, PQ and V/f. The wind fluctuation makes inverter output power harder to follow wind turbine (WT) power. In GC mode, PQ strategy was adopted to balance inverter output power and WT generated power. In SA mode, V/f strategy was applied to keep emergency load voltage stable. The bidirectional smooth transitions between SA and GC mode were well accomplished. Simulation proves the model can survive grid failures or load shedding. The study can be used in research of DG operation control.