Application and Development of a Double Asymmetric Voltage Modulation on a Resonant Dual Active Bridge

The growing market penetration of Electric Vehicles (EVs) requires very efficient bidirectional on-board chargers. These converters must allow the power transfer from the grid to the battery of the vehicle and vice versa, since Vehicle to Grid (V2G) applications enable a mitigation of the peak demand and help regulate both the voltage and the frequency of the grid. In this paper, an innovative double asymmetric modulation was studied and applied to a resonant Dual Active Bridge (DAB), CLLC resonant filter configuration. The results of the study showed a significant efficiency boost and an easier controllability of the converter with respect to more traditional modulations or variable frequency techniques, maintaining Zero-Voltage Switching (ZVS) conditions for all the switches in a wide operating range, from 28 to 100% of the maximum power (4–14 kW). A map of optimum points, where converter losses are minimized, is calculated offline through an algorithm in MATLAB R2024a and a proper interpolation between these points allows any output power for each possible voltage level of the battery to be achieved: from 250 V up to 400 V. The modulations are compared and evaluated through simulations carried out in PLECS, both offline and using hardware-in-the-loop (HIL), as well as through experimental tests.