光伏并网发电系统参数协调优化方法研究

光伏并网发电系统的参数设计对其稳定运行具有重要意义，为此，提出了一种光伏并网发电系统参数的协调优化方法。该方法通过建立包含光伏电池、并网逆变器、变压器和电网的光伏发电系统小信号数学模型，利用特征值分析（根轨迹图）得到各个特征值稳定情况下的系统参数边界值；在此基础上，建立了计及小干扰稳定性、阻尼比和稳定裕度的协调优化目标函数，并采用回溯搜索算法（backtracking search algorithm，BSA）对系统参数进行优化；通过仿真测试，对比分析了参数优化前后系统的动态响应。研究结果表明，在系统遭受到小扰动后，经过参数优化的光伏并网系统能够在0.1s内达到新的平衡点稳定运行，比未优化参数的系统动态响应提高了50%。 

Method of Parameter Coordination Optimization for Grid-Connected Photovoltaic System

The parameter design of grid-connected photovoltaic (PV) system is significant for its stable operation. In this work, a method of parameter coordination optimization was proposed for grid-connected PV system, by establishing the small-signal mathematical model of PV system, including PV cell, inverter, transformer and gird. By analyzing eigenvalues (root locus plot) in stable conditions, the boundary values of system parameters are available. Then the objective function for coordination optimization was built involving small-signal stability, damping ratio and stability margin. And the backtracking search algorithm (BSA) was adopted to optimize the system parameters. The simulation test is carried out to compare the dynamic system responses before and after parameter optimization. Simulation test results show that when system suffers small disturbances, the optimized grid-connected PV system can reach a new stable point within 0.1 s, and its dynamic response is improved 50% than that of the original system.