基于小信号模型的船舶中压直流发电系统稳定性分析

Small Signal Model Based Stability Analysis for Shipboard Medium Voltage DC Generation Systems

为解决船舶中压直流综合电力推进系统的发电系统带恒功率负载存在的电压不稳定问题,采用基于小信号模型的特征值分析的方法,提出一种恒阻感支路同步发电机电压源(voltage-behind-reactance,VBR)模型结合二极管整流器平均值模型的建模方法,通过加入低通滤波器,解决了系统无法直接构成常微分方程的问题,建立了发电系统非线性常微分方程模型,数字仿真验证了其准确性。基于常微分方程模型建立系统的小信号模型,通过分析平衡点的特征值轨迹的方法实现了发电系统的稳定分析。对系统在不同的输入以及设计参数变化情况下的稳定性进行分析,得到了稳定区域,通过定量的数字仿真和定性分析相结合的方式验证了结果的正确性。

In order to solve the problem that the generation system with constant power loads can result in voltage instability in shipboard medium voltage DC integrated power systems, small signal model based eigenvalue stability analysis was employed in this paper. A constant RL-branch synchronous generator voltage-behind-reactance（VBR） model combining diode rectifier average value model modeling approach was proposed. Low pass filters are employed to solve the problem that the system can not be conducted in ordinary differential equation（ODE） form directly, and the nonlinear ODE model for the generation system was constructed. The model was validated by detailed numerical simulation. Based on the ODE model, the small signal model was constructed and the stability of the generation system was analyzed by the eigenvalue loci of equilibrium points. The stability of the system with different inputs and design parameters was investigated, and the stability regions were obtained. The results of the stability analysis were validated by both the quantitative simulation and qualitative analysis.