光储直流微电网多运行工况稳定性分析

Stability Analysis of Optical Storage DC Microgrid under Multiple Operating Conditions

直流微电网的结构越来越复杂,运行工况也越来越多,而现有稳定性分析方法主要针对单一工况。因此研究适用于多工况运行系统的通用稳定性分析方法非常必要。首先,依据不同的运行工况建立光储直流微电网各单元的阻抗模型,利用稳态分析法结合劳斯判据推导得出系统稳定时负载功率及母线电容的边界条件;其次,通过重新定义系统环路增益表达式,得到更具通用性的基于母线电压控制变换器(BVCC)和母线电流控制变换器(BCCC)的稳定性判据,并利用该判据对系统多种运行工况进行稳定性分析,借助所得边界条件对稳定裕度较低的工况计算合适的系统参数,保证系统能够处于稳定运行状态;最后,搭建系统的仿真模型,通过对3种典型工况仿真分析,验证边界条件及稳定性分析结论的准确性。

As the structure of DC microgrid becomes more and more complex and there are more and more operating conditions.However,the existing stability analysis methods are mainly aimed at single operating condition.Therefore,it is necessary to study general stability analysis methods suitable for the system operating in multiple operating conditions.Firstly,the impedance model of each unit of optical storage DC microgrid is established according to different operating conditions,and the boundary conditions of load power and bus capacitance are derived by the method of steady state analysis combined with Routh criterion.Secondly,by redefining the loop gain expression of the system,a more general stability criterion based on BVCC and BCCC is obtained,and the system stability under various operating conditions is analyzed by using this criterion.With the help of the obtained boundary conditions,appropriate system parameters are calculated using the operating conditions with low stability margin to ensure that the system can be in stable operating state.Finally,the system simulation model is built,and the accuracy of the boundary conditions and stability analysis conclusions is verified by the simulation analysis of three typical working conditions.