基于简化FCS-MPC的风电并网逆变器研究

Study of Wind Power Grid-Connected Inverters Based on Simplified FCS-MPC

三相风力发电并网逆变器的模型预测控制存在大量计算问题,导致控制指令的时间延迟,影响控制系统性能,严重阻碍系统应用。为克服上述难点,提出了一种在线简化有限控制集模型预测电流控制算法。该方法通过坐标变换构建αβ坐标下逆变器输出电流的预测模型,利用目标函数对逆变器输出的不同电压矢量进行评估,而无需使用脉宽调制模块。同时,结合电压空间矢量等效变换的原理,引入矢量扇区判断法,进而实现了预测控制过程的在线简化。最后,以带阻感负载三相并网逆变器为控制对象,建立了有限控制集模型预测控制仿真模型,分析了输出电流的稳态与动态性能。仿真结果验证了所提方法的有效性。

Model predictive control is widely applied in the three-phase grid-connected inverters. However, there is a large amount of calculation defects in the process of control, leading to the time delay of the control command, and hindering the application of the model predictive control. In order to solve the problem, a simplified finite control set model predictive current control method is proposed in this paper. The proposed method is achieved based on the stationary reference frame. The opti- mal voltage vector which minimizes a cost function is selected by using an iterative control algorithm without pulse width modulator. Meanwhile, to reduce the calculation defects, a sector distribution method is presented by using space vector modulation. Based on the three-phase grid-connected inverters with a resistive-inductive load, a system simulation model is established. The steady and transient performance of output currents are analyzed. Simulation results are presented to demonstrate the efficacy of the proposed method.