Hybrid Modulation for an SHB-FB Converter Employed in an Integrated Onboard Charger and Auxiliary Power Module

This paper presents a highly integrated EV charger that offers multiple charging modes, including a three-phase input 11kW on-board charger (OBC), an 11kW vehicle-toload (V2L) and a 2.6kW auxiliary power module (APM). The proposed multilevel, three-port topology simultaneously achieves magnetic and circuit integration while accommodating a three-phase (3P) 400-V AC input and a 700V DC bus using 650V GaN HEMTs. A mathematical model of the zero voltage switching (ZVS) boundary of the stacked half-bridge-full-bridge (SHB-FB) converter in the proposed integrated charger is built. Based on this, one hybrid modulation (HM) method is further proposed to improve the full-range efficiency of the SHB-FB converter in the OBC and V2L modes. A prototype is built to validate the proposed integration method and the HM method. Experimental results validate the OBC, V2L and APM modes of the proposed integrated charger and the effectiveness of the HM in improving the medium- and light-load efficiency by achieving full-range ZVS or quasi-ZVS (QZVS).