Power Quality Issues of a Battery Fast Charging Station for a Fully-Electric Public Transport System in Gothenburg City

Journal article, 2015

An automatic fast charger station with a power level of 120 kW is developed for city Bus Line 60 in Gothenburg, Sweden. There are some power quality issues towards the utility grid during the charger operation. The aim of this paper is to explain the project and to present the measurement results with respect to power quality issues. The main specifications of the battery, charger, charging infrastructure and bus route are explained. The measurement results show that the harmonic emission is within the prescribed limit despite the high amount of low-frequency harmonics because of a passive diode rectification. It is suggested to replace the passive diode rectifier with an active front-end converter to eliminate low order current harmonics and to obtain a unity power factor operation. The main contribution of this work is to demonstrate a practical example of an electric charging system for an electric public transport system in Gothenburg.