Energy Management Algorithm for an Advanced EV Fast-Charging System with Bipolar DC-link, Energy Storage and Photovoltaics Integration

This article investigates an energy management algorithm for an advanced electric vehicle (EV) fast charging system with supplementary battery energy storage and photo-voltaics (PV) integration. The considered system is founded on a bipolar, three-wire DC-link for improved flexibility and ensures bidirectional power flow for the converters in order to support a myriad of operating modes. The system consists of a grid converter, isolated dc-dc converters for slow and fast vehicle charging, and non-isolated dc-dc converters: one interfacing the energy storage and another for the PV system. Given the wide possibilities for the operation of the system, an intricate flowchart-based algorithm is proposed for the control of the system. Finally, some of the operation modes are analyzed in detail and further validated using the experimental in-house built model, with the scaled system rated at 1500 V and with a power of up to 20 kW per single converter.