Single-Stage Quad-Active-Bridge Series-Resonant AC-DC Converter: Modulation for Active and Reactive Power

The single-stage AC-DC converters have a high potential to be used in electric vehicle (EV) chargers for vehicle-to-grid (V2G) applications due to its durability, high efficiency and reduced volume. In V2G applications, bidirectional active and reactive power transfer are required. However, reactive power transfer in single-stage AC-DC converters can increase considerably the high frequency (HF) current, reducing the converter efficiency. With the aim of overcoming this limitation, this article proposes a novel modulation for a single-stage three-phase AC-DC Quad-Active-Bridge Series-Resonant (QABSR) converter. The proposed modulation allows to obtain a HF current with a constant and minimum amplitude throughout grid period. Experimental results validate the converter steady-state response for bidirectional active and reactive power transfer.