A bidirectional three-level interleaved DC-DC converter for an electric vehicle charging station operating in a wide range of battery currents and voltages

Charging an Electrical Vehicle (EV) is a process dependent on the specs of their battery in each car with the charger being custom designed. This means that designing the converter for a general EV charging station is very challenging because it must accommodate a wide variety of currents/voltages/powers whilst maintaining a high conversion efficiency and low cost/size. To minimise the size of the magnetics, this paper proposes the use of both multilevel and interleaved technologies to easily support load voltage/current/power scale up. A 3-level flying capacitor converter topology usually deployed in DC/AC application is proposed to be integrated in a 2-channel interleaved implementation where each bidirectional three-level interleaved (B3LI) converter leg switches only half the load current and half the main DC source voltage. The system controller is equipped with phase current balancing and capacitor voltage equalisation control to maintain the system stability along with phase shedding control to reduce losses during low power operation. Simulations are implemented in PLECS software to validate the expected performance and operation of the proposed converter system.