基于功率下垂特性的直流微电网分布式控制

针对直流微电网传统的下垂控制微源间功率分配不均导致系统环流以及直流母线电压偏移造成系统不稳定等问题,提出了一种基于功率下垂特性的直流微电网分布式控制。该方法通过引入微源输出电压、输出功率标幺值来效验微源的输出功率,确定各微源的运行条件,从而实现负载功率按照分配功率与额定功率成比例的方法精确分配,减少了系统环流;通过增加电压偏移量,有效补偿了下垂控制器及等效线路阻抗引起的电压降,使直流母线电压不受负载变化的影响而保持恒定。为了实现该方法,所有确定微源参考电压所需的信息都是通过低速通信网络进行传递。最后,在Matlab/Simulink中搭建两台变换器并联运行的实验模型,分别在低速通信网络故障和负载动态变化的工况下进行仿真试验,结果证明了该方法的可行性与有效性。

Distributed Control of DC Microgrid Based on Power Droop Characteristics

In view of the problems of traditional DC microgrid droop control such as system circulating current caused by power inequality among micro sources and system instability caused by the DC bus voltage deviation,a distributed control of DC microgrid based on power droop characteristics was proposed.In this method,the micro source output voltage and output power in per unit are introduced to verify the output power of the micro source and determine the operating conditions of each micro source,so as to realize the accurate distribution of load power according to the method that the distributed power is proportional to the rated power,and reduce the circulating current of the system;the voltage drop caused by the droop controller and the line impedance is compensated effectively by increasing the voltage deviation,so that the DC bus voltage is not affected by the load change and remains constant.In order to realize the method,all the information needed to determine micro source reference voltage is transmitted through the low-bandwidth communication(LBC)networks.Finally,the experimental model of two transformers parallel operation was built in the Matlab/Simulink,the simulation tests were carried out under the conditions of LBC network failure and load dynamic change respectively.The results prove the feasibility and effectiveness of the method.