三相并网逆变器改进型直接功率预测控制

Improved predictive direct power control of three-phase grid-connected inverter

在三相并网逆变器数学模型基础上,提出了一种基于空间矢量调制的改进型直接功率预测控制,该控制方法在同步旋转坐标系下实现。由于控制系统实际延时两拍,需对下一拍的输出功率和电流进行预估,然后得到两拍后达到目标功率所需要的输出。采用2倍于控制频率的采样频率,准确计算出下一拍的并网功率、电流,同时采用邻域平均通过2次采样计算得到电感辨识值,提高辨识精度,据此计算下一个载波周期三相逆变电路的输出。利用MATLAB/Simulink搭建电路和控制模型进行仿真验证,并通过实验进一步验证,所提出的控制方法具有良好的动静态特性。

Based on the mathematical model of three-phase grid-connected inverter,an improved method of predictive direct power control based on SVPWM（Space Vector Pulse Width Modulation） is proposed,which is implemented in synchronous rotating coordinates. Since the delay of the control system is two cycles,the output power and current of next cycle should be estimated to obtain the grid-connecting power reference after two cycles. The sampling frequency twice the control frequency is adopted to accurately calculate the grid-connecting power and current of the next cycle. The neighborhood averaging method is applied to improve the accuracy of inductance identification by sampling twice,based on which,the three-phase inverter output of next carrier wave period is calculated. The circuit and control model are built with MATLAB/Simulink. The simulative and experimental results show the proposed method has better static and dynamic performance.