This paper presents a novel adaptive-based negative impedance strategy to solve the stability issue of DC microgrids with constant power loads (CPL). It is well known that constant power loads produce negative resistance characteristics, and its significance increases due the high penetration of CPL connected to a DC microgrid. The stability of DC power system starts deteriorating. Also, the stability problem becomes more sever if line inductance is not negligible. Therefore, the proposed strategy designed negative impedance at the source side of the converters which adapt the changes in CPL and DC link voltage deviations to adjust the parameters of negative impedance during live operation. The objectives of the proposed strategy are to provide improved stability margin as compared to the existing virtual negative stabilizer and reduces the voltage drop occurs in DC link voltage due to the consideration of the negative impedance. The adaptive virtual impedance is proposed to counteract the effect of large line inductance and CPL virtual resistance, thus enhancing the damping effect of the DC power system. The DC microgrid system with proposed strategy is carefully modeled using small signal analysis. Matlab Simulation is used to validate the effectiveness and the stable operation of a DC microgrid prototype with the proposed strategy under the variable CPL and the line impedance.

本文提出了一种新颖的基于自适应的负阻抗策略，以解决具有恒定功率负载 (CPL) 的直流微电网的稳定性问题。众所周知，恒功率负载会产生负阻特性，并且由于连接到直流微电网的 CPL 的高渗透性，其重要性增加。直流电源系统的稳定性开始恶化。此外，如果线路电感不可忽略，稳定性问题就会变得更加严重。因此，所提出的策略在变流器的源侧设计了负阻抗，以适应 CPL 和直流母线电压偏差的变化，以调整带电运行期间的负阻抗参数。与现有的虚拟负稳定器相比，所提出策略的目标是提供改进的稳定性裕度，并减少由于考虑负阻抗而在直流链路电压中出现的电压降。提出自适应虚拟阻抗来抵消大线路电感和CPL虚拟电阻的影响，从而增强直流电源系统的阻尼效果。使用小信号分析对具有所提出策略的直流微电网系统进行仔细建模。Matlab 仿真用于在可变 CPL 和线路阻抗下验证具有所提出策略的直流微电网原型的有效性和稳定运行。提出自适应虚拟阻抗来抵消大线路电感和CPL虚拟电阻的影响，从而增强直流电源系统的阻尼效果。使用小信号分析对具有所提出策略的直流微电网系统进行仔细建模。Matlab 仿真用于在可变 CPL 和线路阻抗下验证具有所提出策略的直流微电网原型的有效性和稳定运行。提出自适应虚拟阻抗来抵消大线路电感和CPL虚拟电阻的影响，从而增强直流电源系统的阻尼效果。使用小信号分析对具有所提出策略的直流微电网系统进行仔细建模。Matlab 仿真用于在可变 CPL 和线路阻抗下验证具有所提出策略的直流微电网原型的有效性和稳定运行。