基于卡尔曼滤波的LCL并网逆变器有源阻尼策略

Kalman Filter-based Active Damping Strategy for LCL Grid-connected Inverter

提出利用卡尔曼滤波(Kalman filter)观测器对LCL滤波器的参数进行精确的在线估计的方法。根据LCL滤波器的状态方程设计卡尔曼滤波器,通过检测电网电压、逆变器侧电感电流以及将调制波经过逆变桥增益得到的逆变器输出电压送入卡尔曼滤波器估算出系统的状态量。通过卡尔曼滤波器估算出逆变器侧电感电流、并网电流以及电容电压。将逆变器侧电感电流与并网电流作差得到电容电流,将得到的电容电流与并网电流送入电流控制器,最终实现了有源阻尼与电网电压前馈的并网电流直接控制策略。

This paper proposed that Kalman filter observer was applied to the control system of LCL Grid- connected Inverter. The Kalman filter is designed according to the state equation of the LCL filte. By transmitting the grid voltage and inductance current on the inverter side detecting by sensor and inverter output voltage obtained by Modulation wave through invert-bridge gain to the Kalman filter so that the state parameters canbe estimated. Among them,the grid voltage and inverter output voltage as the system input, the inductance current at the inverter side is used as an observation to correct the preliminary estimate val- ue. The capacitive current and the grid connected current are fed into the current controller. Finally, the di- rect current control strategy of grid connected with active damping and grid voltage feed-forward is realized.