Simplified method of doubly fed induction generator

Abstract

At present, doubly fed induction generator (DFIG) occupies the market of wind turbine due to its controllable rotor AC current, decoupled active and reactive power, and small converter capacity. However, the detailed model with power electronic switch components is complicated and computationally expensive for the simulation which restricts the scale and the speed of the wind power system simulation. This study first analyses the network topology and control strategy of DFIG system including the induction generator, AC–DC–AC converters which largely limit the speed of simulation, and the strategy of stator flux‐oriented vector control. Then a simplified modelling method based on the equivalence of control effect is proposed. Controlled voltage source based on energy balance is used to replace the pulse width modulation control part in both grid side and rotor side. Also, this study simplifies the crowbar circuit considering the low‐voltage ride‐through requirement. At last, this study gives the results of the simplified model and detailed model simulations in PSCAD environment which show accurate matching under different operation states and faults conditions. The results verify that the simplified model can overcome the complex process of power electronics device simulation and solve engineering problems.