三相LCL型并网逆变器d-q阻抗建模及稳定性分析

摘要

In order to avoid the system instability during the dynamic interaction between the three-phase LCL-type grid-connected inverter and the power grid,the impedance model of the LCL filter is established in the d-q synchronous rotating coordinate system with the impedance analysis method,which is on the basis of considering the influence of the phase-locked loop and the current loop. Based on the established model and combined with simulation and experimental results, the influence of control parameters on system stability is analyzed in depth, with the generalized Nyquist curve and the current waveform in time domain as the indicatrix. It is concluded that the larger scale coefficient of the PLL and current loop can both make the system more unstable And the correctness of the model is verified.%为有效避免三相LCL型并网逆变器与电网动态交互过程中导致系统不稳定问题,在综合考虑锁相环和电流环影响的基础上采用阻抗分析方法在d-q同步旋转坐标系下建立了LCL滤波器的阻抗模型.基于所建模型并结合仿真和实验结果,以广义奈奎斯特曲线和电流时域波形为指示量,深入分析了控制参数对系统稳定性的影响,得出锁相环比例系数越大系统越不稳定,电流环比例系数越大系统越不稳定的结论,验证了所建立的阻抗模型的正确性.