A comparative analysis of supraharmonic emission by DC fast chargers used for electric vehicle charging

In recent years, concerns about the environment and the depletion of fossil fuels have encouraged the incorporation of electric vehicle technology in the automotive market. As the increasing usage and growth of electric vehicles (EVs) along with the advancement of power electronic converters significantly impact the power quality of the electrical grid. This paper addresses a new ongoing power quality issue known as supraharmonics, which occurs in the frequency range of 2 to 150 kHz due to electric vehicle chargers. Among various levels of EV chargers, DC fast chargers have become more popular in recent years for quick charging of batteries. The charging time of the EV mainly depends on the optimized selection of the DC-DC converter implemented in the charging circuit. The effective use of a DC-DC converter should increase battery performance and lifespan. Consequently, this work investigates the supraharmonic emissions produced by a DC fast charging station with four number of chargers connected to an electrical distribution system. Several DC/DC converter topologies in EV fast chargers were designed and developed using MATLAB/Simulink software. The simulation has been carried out to analyze the supraharmonic emission from the designed converter topologies in different operating conditions. The results of the simulations have been analyzed for comparative analysis of supraharmonic emission from different converter topologies. Finally, from the analysis, a suitable converter topology with reduced supraharmonic emission has been suggested.