Photovoltaic (PV) generators have continuously increased in recent years, whose power is usually controlled through the perturbation and observation (P&O) method. In essence, the P&O method is nonlinear and discontinuous. Hence, the conventional small-signal stability analysis is not suitable anymore when the influence of the P&O-based power control is considered. Focusing on this problem, this paper adopts the nonlinear describing function (DF) method to conduct the accurate stability analysis of PV generators with consideration of P&O-based power control. The detailed procedures about the DF method are introduced, and then the related influence factors like perturbation size, filters, and so on are analyzed quantitatively. Furthermore, the comparison with the conventional stability analysis methods is made, which suggests that the DF method can effectively enhance the accuracy of the stability analysis. All the conclusions are verified by the real-time hardware-in-loop tests.

中文翻译：

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考虑基于 P&O 的功率控制的光伏发电机稳定性分析


近年来，光伏（PV）发电机不断增加，其功率通常通过扰动和观测（P＆O）方法进行控制。本质上，P&O 方法是非线性且不连续的。因此，当考虑基于P&O的功率控制的影响时，传统的小信号稳定性分析不再适用。针对这一问题，本文采用非线性描述函数（DF）方法，结合基于P&O的功率控制，对光伏发电机进行精确的稳定性分析。介绍了DF方法的详细流程，并对扰动大小、滤波器等相关影响因素进行了定量分析。此外，与传统的稳定性分析方法进行了比较，表明DF方法可以有效提高稳定性分析的准确性。所有结论均通过实时硬件在环测试得到验证。