LCL型并网逆变器电流的自耦PID控制方法

Auto-coulping PID Control Method for LCL Grid-connected Inverter Current

针对三相并网逆变器功率突变时电流跟踪速度慢和超调量大的问题,提出了基于自耦PID控制理论的电流控制方法。该方法将LCL型三相并网逆变器的已知或未知内部动态与电网电压引起的扰动视为总扰动,进而非线性扰动系统可以被等价为线性扰动系统。构建了在总扰动反相激励下的受控误差系统,据此设计了基于速度因子的自耦PI电流控制器,理论分析了自耦PI闭环控制系统具有良好的鲁棒稳定性和抗扰动鲁棒性。仿真实验表明了该方法具有响应速度快、控制精度高、抗扰能力强的动态品质,其中响应时间约为2 ms,在分布式电源并网领域具有良好的应用前景。

A current control method based on auto-coupling PID control theory is proposed to address the issues of slow current tracking speed and large overshoot when the power of three-phase grid connected inverters suddenly changes.This method considers the known or unknown internal dynamics of LCL type three-phase grid connected inverter and the disturbances caused by the grid voltage as total disturbances,and then the nonlinear disturbance system can be equivalent to a linear disturbance system.Furthermore,a controlled error system under the inverse excitation of total disturbance is constructed.An auto-coupling PI current controller based on speed factor is designed accordingly.Theoretical analysis shows that the auto-coupling PI closed-loop control system has good robust stability and disturbance resistance robustness.Simulation experiments have shown that this method has dynamic qualities such as fast response speed,high control accuracy and strong anti-interference ability.The response time is about 2 ms,and the proposed method has good practical application prospects in the field of distributed power grid connection.