Multi-module DC-DC converter-based fast chargers for neighborhood electric vehicles

Abstract

To allow a wide adoption of Neighborhood Electric Vehicles (NEVs), low-speed EVs, the EV battery's fast recharging is necessary. This will further increase the utilization of EVs due to the reduced charging duration. To achieve fast recharging, several studies have introduced advanced power electronics technologies to allow wider acceptance for EVs by the public. Among these power electronics conversion systems, the DC-DC conversion stage plays an essential role in supplying energy to the EV via charging the EV's battery. Accordingly, in this paper, a multi-module Input-Series Output-Parallel (ISOP) DC-DC converter is presented for NEVs. The multi-module ISOP DC-DC converter is Dual Active Bridge (DAB) based topology. Unlike the conventional ISOP DC-DC converter, only one H-bridge is employed at the input side, while the intermediate high-frequency transformer and the H-bridge employed at the output side are of modular structure. Since only one bridge with a single capacitor is used at the input side, the power balance between the employed DAB units is accomplished via direct output current sharing, where stability is ensured without using the input voltage sharing control approach. Two Matlab/Simulink model is presented to verify the presented concept using reflex charging algorithm, where the first model uses the small-signal model to present the behavior of the converter under transient condition, while the other Matlab/Simulink model is time-domain based simulation. The controller is tested using three DAB units with parameter mismatch where each unit is rated at 1. 5 kW to achieve an overall power of 4. 5 kW.