In this paper, an energy coordination control method based on intelligent multi-agent systems (MAS) is proposed for energy management and voltage control of a DC microgrid. The structure of the DC microgrid is designed to realize the mathematical modeling of photovoltaic cells, fuel cells and batteries. A two-layer intelligent MAS is designed for energy coordination control: grid-connection and islanding of a DC microgrid is combined with energy management of PV cells, fuel cells, loads and batteries. In the hidden layer and the output layer of the proposed neural network there are 17 and 8 neurons, respectively, and the “logsig” activation function is used for the neurons in the network. Eight kinds of feature quantities and 13 different actions are taken as the input and output parameters of the neural network from the micro-source and the load, and the as the control center agent’s decision-makers. The feasibility of the proposed intelligent multi-agent energy coordination control strategy is verified by MATLAB/Simulink simulation, and three types of examples are analyzed after increasing the load. The simulation results show that the proposed scheme exhibits better performance than the traditional approaches.
Based on the respective characteristics of line-commutated converter high-voltage direct current (LCC-HVDC) and voltage-source converter high voltage direct cur- rent (VSC-HVDC), two additional emergency DC power support (EDCPS) controllers are designed, respectively. In addition a coordinated control strategy based on a hybrid multi-infeed HVDC system for EDCPS is proposed. Considering the difference in system recovery between LCC-HVDC and VSC-HVDC in EDCPS, according to the magnitude of the amount of potential power loss, the LCC-HVDC and VSC-HVDC priority issues of boosting power for EDCPS are discussed in detail. Finally, a hybrid three-infeed HVDC that consists of two parallel LCC-HVDCs and one VSC-HVDC that is built in PSCAD/EMTDC are simulated. The effectiveness of the proposed approach is verified based on this hybrid three-infeed HVDC system.