逆变器侧电流反馈的LCL型三相光伏并网逆变器解耦控制

为了实现LCL型三相光伏并网逆变器dq轴的解耦控制,同时提高系统的动态响应速度,在同步旋转坐标系下,提出一种适用于逆变器侧电流反馈的前馈解耦控制策略。并在电压外环中引入光伏阵列功率前馈、电流内环中引入电网电压前馈。视各耦合项为扰动,采用闭环传递函数的求解方法以获取实现解耦控制的前馈系数,同时分析了滤波器参数在发生变化时其对dq轴解耦效果的影响。通过Matlab建立系统仿真模型,仿真结果表明:所提解耦控制策略使LCL型三相光伏并网逆变器不仅实现了dq轴的解耦控制,而且在保证强鲁棒性及高入网电流质量条件下具有良好的动、静态性能。

Decoupling control strategy with inverter-side current feedback for LCL-type three-phase PV grid-connected inverter

In order to realize the decoupling control of dq axis for three-phase PV grid-connected system and speed up the system dynamic response speed, a decoulpling control strategy is proposed in the synchronous rotating reference frame. Meanwhile, PV array power feed-forward and full grid-voltage feed-forward control are respectively introduced into the voltage outer loop and current inner loop. The coupling terms are considered as disturbances, and the feed-forward decoupling coefficients are obtained by solving the closed loop transfer function, and the decoupling effect of the dq axis is analyzed when the filter parameters change. The system simulation model is established by Matlab, the simulation results show the proposed control strategy makes the three-phase PV grid-connected inverter with LCL filter not only realize the decoupling control of dq axis, but also has good static and dynamic performance under the condition of the strong robustness and high grid current quality. This work is supported by Science and Technology Support Project of Gansu Province (No. 1204GKCA038).