Impact of Fast-Chargers for Traction Batteries on Distribution Network

Abstract

High-power converters with high frequency pulse transformers are used in fast-chargers for electric vehicles to decrease their size and price. These converters and their input rectifiers have significant impact on distribution network. Distribution net impact can be split into 3 basic domains: EMC issues, unusually high local concentration of consumed power and presence of higher harmonics in input current. The third domain is the main objective of the article. An advantageous solution of input rectifier was proposed. A conception with a passive diode input rectifier and a DC-link with an extremely low capacity is used in this conception. Dimensioning of this DC-link capacitor to ensure mentioned low impact on distribution net is presented. The final part of the paper demonstrates overall applicability of RN14-140 fast-charger pattern via presentation of high harmonics of phase current measurements.