Cooperative control for modular charging systems of virtual rail electric vehicles

摘要

Virtual rail electric vehicles have lately received great attention for public transportation due to their small pollution, low energy consumption, and safe characteristics. The virtual rail transit with onboard supercapacitors has been considered as an effective way to achieve the zero emission objective. However, the on-board supercapacitors require a modular charging system consisting of multiple charging modules due to the limited charging time. The classical decentralized charging method results in the current imbalance among charging modules, which may degrade the reliability and lifetime of the charging system. In this paper, a cooperative charging method is proposed for the modular charging system to alleviate the current imbalance among modules. The cyber-physical model of the modular charging system is established with state-space method and graph theory. A cooperative controller is designed with a voltage loop stabilizing the output voltage and a current loop balancing charging current of modules. Both simulation and experiment results are provided to verify the proposed charging method.