基于I-V下垂控制的直流微电网动态特性分析与改善

本文对孤立直流微电网动态特性进行了分析,并提出了改善策略.在孤网条件下,电压主要靠系统中基于储能的DC/DC变换器进行控制,因此多DC/DC变换器动态特性即可反应系统全局的动态特性.本文中各DC/DC变换器采用I-V下垂控制,并以负载的变化量为输入,变换器输出电流、占空比及母线电压为状态变量对多DC/DC变换器进行了大信号模型的建立.基于上述模型,本文对输出电流动态特性的影响因素进行了根轨迹分析,最后提出自适应P控制策略以提高直流微电网中的动态特性.最后通过仿真对提出的模型及控制策略进行了验证.

Analysis and improvement of DC microgrid dynamic performance based on I-V droop control

The dynamic performance of DC microgrid has been analyzed and improved by this paper. In an islanded system, the bus voltage is controlled by paralleled DC/DC converters based on the energy storages, so the dynamic performance of the paralleled converters can reflect the dynamic of the system. In this paper, the I-V droop control method is used for the paralleled converters. The large signal model is built. In this model, the input is the load variation and the state variables are converters' output currents, duty ratios and the bus voltage. Based on this model, the root locus method is used to analyze the dynamic performance of the converters' output current. Thus, the adaptive P control method is proposed to improve the dynamic performance of the DC microgrid. The simulation has been conducted to verify the proposed model and the control method.