\Multi-objective isolated multiple active bridge DC/DC converter for electric vehicle chargers with local generation and storage for reducing the supplied power from the grid

• Development of an independent control method for multiple active bridge converters applied to EV chargers with local generation and storage. • Reduction of the grid energy consumption in the EV chargers by optimizing the power from local sources. • Incorporation of a reactive power control for increasing efficiency by adding a phase-shift between voltage and current of the same port. • Validation of the proposed solution in simulations and real experiments in a 1 kW prototype. • Power loss analysis. In order to reduce the impact of fast electric vehicle (EV) chargers on the grid, incorporating local generation and storage will play a key role. Thus, the power grid does not need to provide the full power to charge the EV battery but a fraction, reducing the cost of new grid infrastructure, particularly when EV chargers become massive. In this work, we propose the application of a multiple active bridge (MAB) converter for an EV charger consisting of a multiple-port system connected to the grid, the EV battery and local batteries and photovoltaic panels. This forms a 4-port or even larger system if required. For such a complex system, a MAB converter, as analyzed in this work, suits perfectly due to its intrinsic galvanic isolation and its reduced size, in comparison with a multi-converter solution, one per connected device. The paper details how to control the MAB converter to achieve independent objectives in each port, such as constant current/constant voltage charge for the EV battery, maximum power point tracking (MPPT) for photovoltaic generation and the reduction of power peaks supplied by the grid. The proposed control is validated through a 4-port converter simulation and a 3-port converter prototype. It shows that the suggested solution is 3.4% more efficient than the corresponding multi-converter solution, and using a reduced number of switches. For this particular example, the power peak delivered to the EV battery is 80 kW while the grid delivers only 20 kW, the exact fraction depends on the available local generation and storage. Furthermore, the proposed solution is 1.8% more efficient in comparison with state-of-the-art MAB control techniques under the same conditions. This efficiency increase is based on the reactive power control inside the converter.