The Development of a Multi-port Slow Charger for Electric Vehicles

Background/Objectives: The EV charging infrastructure consists largely of the power supply facilities, charger, interface, and information system. Charger that supply electricity from an electricity provider to EV batteries can be classified as direct charging, noncontact charging, and battery exchange. Methods/Statistical Analysis: Direct charging is divided into slow charging and fast charging based on the charging time. At present, 90% of the charger market is slow chargers. The points to be solved of slow charger is the user discomfort and installation cost due to limitation of space and time. Findings: To solve this point, proposed the multi-port slow-charging system in this study. It reduced the installation and maintenance costs in comparison to existing chargers and improved user convenience by providing a multi-port charging feature, which enables multiple EVs to be charged simultaneously with one charger, and by providing a user interface through the driver's smart phone to implement the V2G standard. A prototype of the proposed multi-port slow-charging system was implemented, and performance tests were conducted in situations similar to the actual environment to verify the performance of the proposed system. An analysis of the performance test results reveals that the proposed system was above the KC(Korea Certification) standard values. Furthermore, the proposed multi-port slow-charging system can reduce costs by about 50%, compared to the existing charging system, based on the manufacturing and maintenance costs of the charger. Application/Improvements: The user interface of the charger was interfaced with the driver's smart phone, implementing a communication system that is similar to the V2G protocol in order to construct an ICT charging system that can be monitored remotely in real time. It is expected to contribute to the expansion of the EV charging infrastructure.