双馈风电机组低电压穿越非线性变结构控制策略研究

提出一种基于精确线性化变结构控制的双馈感应风力发电机(DFIG)的低电压穿越控制器设计方法。建立了DFIG在同步旋转dq坐标系下的非线性数学模型,在此模型基础上,采用精确线性化将原非线性系统模型转化为线性系统模型。应用变结构控制原理设计DFIG的发电机转子侧及电网侧变流器的控制器,同时通过PI控制以稳定直流侧电容电压。最后,利用MATLAB仿真软件搭建了6×1.5 MW的DFIG系统仿真模型,仿真结果表明,所设计的控制器能够在电压跌落后抑制转子过电流以及直流母线过电压现象,实现了DFIG的低电压穿越。

A Study on the Non-linear Variable Structure Control Strategy for the Low Voltage Ride Through of the Doubly-fed Induction Generator

This paper presents a design method for the low voltage ride through controller of the doubly fed induction generator (DFIG) based on variable structure control of exact linearization.A nonlinear DFIG mathematical model is established in the synchronous rotating dq coordinate system.On that basis,the original nonlinear system model is transformed into a linear system model by means of exact linearization.A DFIG controller for the generator rotor side and the grid side is designed in the principle of variable structure control,and the DC side capacitor voltage is controlled through PI.Finally,a 6× 1.5MW DFIG system simulation model is built through MATLAB simulation software.Simulation results show that the designed controller can suppress rotor over-current and DC bus overvoltage after voltage drop,thus realizing low voltage ride through for the DFIG.