Battery Charger for Electric Vehicle Traction Battery Switch Station

TLDR

The paper introduces a commercial fast charger designed for lithium‑ion electric vehicle propulsion batteries. The charger operates in a battery‑switch station using a dual‑stage AC/DC converter: a three‑phase full‑bridge diode rectifier with a shunt active power filter generates an uncontrolled DC bus that meets grid harmonic and power‑factor limits, while six interleaved dual‑parallel DC‑DC converters in the output stage charge the battery. The charger can operate in constant current, constant voltage, and constant power modes, and simulations and experiments confirm its functionality.

Abstract

This paper presents the functionality of a commercialized fast charger for a lithium-ion electric vehicle propulsion battery. The device is intended to operate in a battery switch station, allowing an up-to 1-h recharge of a 25-kWh depleted battery, removed from a vehicle. The charger is designed as a dual-stage-controlled ac/dc converter. The input stage consists of a three-phase full-bridge diode rectifier combined with a reduced rating shunt active power filter. The input stage creates an uncontrolled pulsating dc bus while complying with the grid codes by regulating the total harmonic distortion and power factor according to the predetermined permissible limits. The output stage is formed by six interleaved groups of two parallel dc-dc converters, fed by the uncontrolled dc bus and performing the battery charging process. The charger is capable of operating in any of the three typical charging modes: constant current, constant voltage, and constant power. Extended simulation and experimental results are shown to demonstrate the functionality of the device.