双直流母线直流微电网的协调控制

Coordination Control of DC Microgrid with Two DC Buses

为便于不同电压等级的直流负荷接入直流微电网,设计了基于双直流母线构架的直流微电网协调控制策略。双直流母线直流微电网由2电压等级不同的独立直流微电网通过双向DC/DC变换器连接构成。将锂电池超级电容组成的混合储能系统应用于直流子网中,并根据双向变换器两侧子网的电压–功率下垂特性,对两侧电压进行了归一化处理,提出了适用于连接2直流子网的双向DC/DC变换器下垂控制;最后,通过d SPACE验证了系统协调控制策略的可行性。实验结果表明,此控制策略可以根据2直流子网电压大小有效控制子网间的功率传输,实现了整个系统功率的平衡,提高整个系统的运行可靠性。

In order to meet the demands of different DC voltage levels of DC loads, we put forward a coordination control strategy of DC microgrid with two DC buses. The proposed system contains two DC microgrids with different voltage levels, and the two microgrids are connected with a bidirectional converter which is used to keep balance of the power in both sides and improve the operational reliability of the entire system. Based on the droop characteristics of bidirectional converter, the droop control of Buck/Boost converter is proposed to achieve a power balance in the whole system. Besides, according to the high power density of super capacitor and the high energy density of battery, hybrid energy storage sys- tem（HESS） is adopted to optimize the system operation and prolong the service life of the battery. Finally, the availability of the control strategy is verified by dSPACE. The experimental results show that the power flow between the high and low voltage DC bus can be achieved through the control of the bidirectional converter, ensuring the stable operation of the system.