电网电压不对称跌落下DFIG控制策略的仿真研究

Simulation Research on Control Strategy of Doubly Fed Induction Generatorunder Unbalance Power Grid

新能源并网下,三相不平衡工况频繁发生,产生的负序分量,将在双馈异步风力发电机(doubly fed induction generator, DFIG)系统中诱发定子侧有功、无功功率以及电磁转矩的二倍频脉动,直流母线侧电容电压二倍频脉动,网侧三相不对称电流等现象。本文建立DFIG在电网电压不平衡下网侧及转子侧的数学模型并提出相应的控制策略,基于LabVIEW仿真平台,模拟电网出现的各类电压不对称跌落工况,所述抑制策略的仿真结果能够很好的保证DFIG穿越故障,为实际运行提供理论依据。

Under the combination of new energy sources,three-phase unbalance conditions frequently occur,and the negative sequence component will induce double frequency pulsation of active and reactive power as well as electromagnetic torque on the stator side,double frequency pulsation of capacitor voltage on the DC bus side,three-phase asymmetric current on the grid side and other phenomena in the doubly fed induction generator(DFIG)system.In this paper,the mathematical models of DFIG on the grid side and the rotor side under unbalanced grid voltage are established and the corresponding control strategies are proposed.Based on the LabVIEW simulation platform,various voltage asymmetrical drop conditions of the grid are simulated.The simulation results of the suppression strategies can well ensure that the DFIG can ride through fault,and provide a theoretical basis for the actual operation.