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This paper studies a battery energy storage system based on the hexagonal modular multilevel direct ac/ac converter with focus on a control method for state-of-charge (SOC) balancing of the battery units. First, the system structure and the operating principle of the hexagonal multilevel converter, including the branch voltage and the power, are analyzed and simulated, respectively. Then, the mathematical model of the energy storage submodule consisting of the battery energy storage unit and H-bridge submodule cell is developed in PSCAD/EMTDC software. After that, a SOC balancing control strategy is proposed, including the branch SOC balancing between the converter’s six branches and the individual SOC balancing between the 14 cascaded converter cells in each branch, which is realized by controlling currents in branch modules. Currents in the branches are controlled by the internal model principle. Finally, the effectiveness of the control strategy is verified in simulation.

The emergence of microgrid technology provides a new method for distributed generation connecting to the grid. However, it creates a new problem that people need to think about how to manage a number of microgrids in a certain area to obtain higher power supply reliability. This paper studies a new distribution network topology named honeycomb distribution network which is proposed by our research group. Firstly, this paper makes a brief introduction of the topology and active microgrids and smart power/information exchange base stations in the topology. Secondly, mathematical probability method is used to analyze the power supply reliability of the topology. Finally, in order to show the high reliability of the topology more intuitively, revised formulas based on the minimum cut set method are introduced to calculate the reliability parameters of modificative IEEE-RBTS BUS6 F4 test system. Calculation results are shown to verify the high reliability of honeycomb distribution network.

This paper proposes a novel energy exchange node topology which can connect the AC and DC microgrids easily. On this basis, a reliable power flow control strategy is proposed to improve the performance of microgrids. A comprehensive analysis of the control strategies commonly used in AC and DC microgrids is presented. Then, the topology and power flow control strategy of the novel energy exchange node which can redistribute the energy of the island group are proposed. In order to verify its effectiveness and performance, a physical model is built and the simulation verification is carried out on MATLAB/Simulink software. The results show that the novel energy exchange node can effectively cooperate with the microgrid control strategies to realize the power flow exchange among the microgrids, which mean the realization of the energy redistribution among island group.

In this paper, we researched a vehicle terminal-based Intelligent Travel System. We gave the overall design of the system architecture, and gave the function of each module. The system could provide users with personalized service focus on users’ preferences and user-based personalized intelligent location information service. We proposed recommendation algorithm focus on user-based personalized intelligent location information, built a set of strong association rules, and optimized foundation algorithm. The results showed that the optimized algorithm had better performance and could satisfy the user’s personalized travel needs.

In the paper, the mobile payment technology is applied to smart travel. Firstly, we design the overall functional structure diagram of the mobile payment system and describe the main function modules. Secondly, we design database system and a hybrid encryption algorithm based on DES and ECC, which ensures the security of the system. Finally, we test and analyze the result of the mobile payment system.