基于谐波状态空间理论的LCL型并网逆变器谐波交互及稳定性分析

电网的逐渐电力电子化引发了谐波谐振、系统不稳定。为获得系统详细的谐波交互情况和不稳定模式，针对三相LCL型并网逆变器，首先基于谐波状态空间(HSS)理论建立其双电流环控制下的数学模型；其次深入研究公共连接点处电网背景谐波电压对逆变器直流侧电压和交流侧电流的影响，以及直流侧电压扰动对交流侧的影响；同时推导出谐波交互的耦合系数矩阵，并分析耦合特性；然后在HSS数学模型的基础上，利用阻抗分析法揭示了弱电网情况下逆变器谐波振荡产生的机理；最后将实验、仿真模型结果与数学模型结果进行了对比，验证了数学模型的有效性以及理论分析结果的正确性。

Analysis on harmonic interaction and stability of LCL grid-connected inverter based on harmonic state space theory

The electronization of power grid causes harmonic resonance and system instability. In order to obtain the detailed harmonic interaction and instability mode of the system, the mathematical model of three-phase LCL grid-connected inverter under dual current loop control is established based on HSS(Harmonic State Space) theory firstly. Secondly, the influence of grid background harmonic voltage at PCC(Point of Common Coupling) on DC voltage and AC current of the inverter, and the influence of DC voltage disturbance on AC side are deeply studied. At the same time, the coupling coefficient matrix of harmonic interaction is derived, and the coupling characteristics are analyzed. Then, the mechanism of inverter harmonic oscillation in weak grid is revealed by impedance analysis method based on HSS mathematical model. Finally, the results of experiment and simulation model are compared with the results of mathematical model to verify the effectiveness of the established mathematical model and the correctness of theoretical analysis conclusion.