基于双采样的LCL型并网逆变器并网电流间接控制研究

Research on grid-connected current indirect control of LCL-type grid-connected inverter based on double sampling

在并网逆变器滤波方面,LCL型滤波器比LC型滤波器具有更加优良的高频谐波滤除能力,但是LCL型滤波器的谐振效应也给并网系统的稳定性带来一定的挑战。实际的并网逆变器通常采用逆变器侧电流和电容电压作为反馈进行控制,在分析LCL型并网逆变器结构的基础上,文章提出一种逆变器侧电流反馈控制并网电流和电容电压反馈抑制谐振的并网逆变器控制方案,无需逆变器外部增加电流传感器,给出了精确的并网电流参考值计算方法。实验验证了文章所提控制方案的有效性。

In terms of grid-connected inverter filtering,LCL-type filter has better high-frequency harmonic filtering ability than LC-type filter,but LCL-type filter also brings some challenges to the stability of grid-connected system.The resonance effect needs to be solved to ensure the stable operation of the system.The actual grid-connected inverter usually samples the inverter-side current and capacitor voltage as feedback for control.On the basis of analyzing the structure of LCL-type grid-connected inverter,this paper proposes a grid-connected inverter control scheme that uses inverter-side current feedback to control grid-connected current and capacitor voltage feedback to suppress resonance.It does not need to add current sensors outside the inverter.this paper also gives an accurate calculation method of grid-connected current reference value.Experiments verify the effectiveness of the proposed control scheme.