光伏系统模型的多时间尺度降阶

为了解决光伏接入的电力系统模型复杂和分析困难的问题,提出了一种简单实用的光伏发电系统模型降阶方法。综合考虑主电路及控制策略建立了光伏发电系统小信号模型,分解模型中的多时间尺度特性以确定快速状态和慢速状态,并用相对速度估计法验证了快慢状态分解的正确性,避免了由摄动参数选取不当引起的降阶前后系统稳定性不一致的问题。通过忽略快动态变量对原模型进行降阶,添加校正项得到了零阶近似模型和一阶近似模型。最后在MATLAB中分别对比了降阶模型、校正模型与详细模型的动态响应和计算误差。研究结果表明,降阶模型和校正模型均能够正确反映详细模型在小扰动下的动态响应,且在提高计算速度、简化分析过程方面有明显优势。

Multi-time scale reduction of photovoltaic system models

In order to solve the model complexity and analysis difficulty of electric system joined up by photovoltaic power system, a simple and practical model reduction method of photovoltaic power system is proposed. Considering the main circuit and control strategy, a small signal model of photovoltaic power generation system is established. On this basis, the multi-time scale characteristics of the system model are decomposed to determine the fast and slow states. The correctness of the fast and slow states decomposition is verified by the relative velocity estimation method, which avoids the inconsistency of the stability of the system before and after the reduction caused by the improper selection of perturbation parameters. By ignoring the fast dynamic factors, the order of the model is reduced, and the zero-order approximation model and the first-order approximation model are obtained by adding correction terms. Finally, the dynamic responses and calculation errors of the reduced order model, the corrected model and the original model are compared in MATLAB. The results show that the reduced model and the correction model can correctly reflect the dynamic response of the detailed model under small perturbations, and have obvious advantages in improving the calculation speed and simplifying the analysis process.