Research project on the integration of e-car charging stations in DC networks

The German Fraunhofer Institute for Manufacturing Engineering and Automation IPA is working with other partners from industry and research on the integration of charging stations for electric cars into commercial DC networks in the »DCI4Charge« project. Such DC grids are more cost-effective for industrial applications than AC grids, says Jonas Knapp, head of the Industrial Microgrids and Energy Storage project at Fraunhofer IPA. »More and more companies are therefore using direct current in production,« says Knapp.
It is therefore high time to also integrate the charging infrastructure for electric vehicle fleets into the system. Until now, this has only been possible in a roundabout way – i.e., with the help of rectifiers: As long as the charging stations in the parking lots are supplied by the AC grid, alternating current has to be converted into direct current in order to charge the batteries. In the case of AC charging stations, this is done in the vehicle’s on-board charger; in the case of fast charging stations, the AC is already rectified in the charging station. The aim of the DCI4Charge project – the abbreviation stands for industrial direct current for charging – is to supply the DC charging station directly from a company’s DC grid and, conversely, to provide virtual or temporary support for the industrial DC grid.
»By integrating the charging stations into the DC grid, we can not only save energy, but also use the capacity of the vehicle batteries to supply energy to the companies,« adds project manager Knapp. »In this way, consumption peaks can be buffered and energy costs reduced.«
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