A Hybrid Three-Port Topology for Urban Charging Stations
Mohammadreza Khodaparast Klidbari, Naser Souri, Zahra Sadat Habibolahi, Hamid Montazeri Hedeshi
TL;DR
This paper addresses the need for flexible, efficient charging at urban EV stations by proposing a fixed-frequency, fixed-structure, hybrid three-port isolated DC-DC converter based on LLC resonance. The design uses a two-winding transformer to prevent circulating currents and a secondary-stage switch to achieve a wide output range, while enabling primary-side ZVS without feedback, reducing control complexity and component count. Experimental validation on a ~600 W prototype demonstrates 96% peak efficiency across asymmetric port loads, confirming the approach's viability for urban charging infrastructure. The work offers a practical, cost-effective solution for integrating fast and slow charging within a single, galvanically isolated converter platform.
Abstract
Electric vehicles are rapidly gaining popularity as a sustainable alternative to conventional gasoline. In urban areas, chargers with different ratings can accommodate the diverse needs of electric vehicles. However, the available multiport topologies have variable switching frequencies. This paper introduces a hybrid multiport isolated DC-DC converter for urban charging stations, incorporating fast and slow charging ports with a fixed switching frequency. It provides isolation and enables soft switching on the primary side of the converter without circulating current on its secondary side. The primary side does not need feedback, which reduces complexity. The second stage generates a wide output voltage range to charge the electric vehicle battery by employing a switch. In addition, the proposed topology offers reduced component count and simple control with fixed-frequency operation. This paper provides the concept and the operation modes. Experimental results are provided to validate its features. The prototype converter achieves 96\% peak efficiency.