Multifunctional Onboard Charger for Electric Vehicles Integrating a Low-Voltage DC–DC Converter and Solar Roof

Abstract:
This project presents a multifunctional onboard charger (OBC) is proposed that integrates the power conversion circuits for a high-voltage battery (HVB) and low-voltage battery (LVB), where the solar roof is attached to the electric vehicle (EV). Control methods are presented for systematic operation in four modes depending on the energy sources [i.e., ac grid and photovoltaics (PVs)] and batteries (i.e., HVB and LVB): grid-to-vehicle (G2V), vehicle-to-grid (V2G), HVB-to-LVB (H2L), and HVB + PV-to-LVB (HP2L). The proposed OBC reduces the dc-link capacitance by including an active power decoupling (APD) circuit in the front-end. In addition, the proposed OBC achieves a high-power density and efficiency by selective operation of the topology depending on the mode. Previous studies were limited by the rated power of the low-voltage dc–dc converter (LDC), but the proposed OBC can effectively use power from the solar roof while charging the HVB and LVB simultaneously. The simulation results can be evaluated by using Matlab/Simulink Software.

Keywords: — Electric vehicle (EV), multifunctional onboard charger (OBC), OBC, photovoltaic (PV), solar roof.