Study on Parallel Current Sharing Technology of Power Module in DC Charging Pile for Electric Vehicle

In order to meet the changing requirements of multiple types of electric vehicles, the layout and development of quick charging and DC charging piles are rapid. The modularized DC charging pile becomes the popular research field. Due to the differences in the parameters of each module in the charging pile, the current assumed by each module in parallel may not be the same, leading to the premature aging and damage of some modules and affecting the service life of the charging pile. In this paper, the isolated full-bridge DC/DC converter is taken as the power module topology, and the parallel current-sharing technology is studied. Two control methods are designed, one is the double-closed-loop cascade control of the voltage outer loop and the current inner loop, and the other is the adaptive double-loop based on charging mode. The current-sharing loop is added in the two controllers and the averaging-current method is adopted and the simulation verification of two-module and four-module in parallel is carried out. Through the comparison of load switching, the advantages of the he adaptive double-loop control method in the multimodule parallel connection, such as large stability margin and fast response speed, are validated.