Grid-friendly integration of electric vehicle fast charging station based on multiterminal DC link

Abstract

The success of the e-mobility will inevitably be linked to the network hosting capacity of new electrical vehicle chargers. A massive deployment of electrical vehicles will considerably stress the current LV distribution grids due to the load increase. Moreover, the integration of electrical vehicle fast charging stations may produce severe grid congestions if adequate countermeasures are not applied. This scenario allows to explore new ways of network operation to enhance the integration of the electrical vehicles avoiding additional network reinforcements. This paper proposes a new topology of electrical vehicle fast charging station based on a multiterminal DC-link arrangement but using the same power electronic devices of the conventional ones. Each terminal is connected to different LV feeders in such a way that the electrical vehicle charge can be shared between the upstream secondary substations. In addition, the multiterminal DC link is able to contribute to the LV voltage regulation by adequate reactive power injections. The proposal has been experimentally validated on a scaled-down system which mimics the main properties of an actual LV distribution system. The obtained results show that the proposed solution can be considered an e-mobility enabler due to the minimization of the charging impact and the maximization of the use of the current assets.