Variations in Supraharmonic Emission (2-150 kHz) of an EV Fast Charging Station under Different Supply- and Operating Conditions

This paper presents the outcome of a study of variations in the supraharmonic (SH) emission of an electric vehicle fast-charging station (FCS), under different supply voltage harmonic distortions and operating conditions. FCSs can operate under a broad range of operating conditions that can depend on the state of charge and capacity of the connected vehicle's battery, and this might result in different emissions. The aim is to determine the factors that influence the primary SH emission of the FCS by making a so-called "Supraharmonic fingerprint". A test set-up is developed to operate the FCS under different conditions and the emission in certain frequency bins with characteristic emission is analyzed. It is found that some SH components are related to injected low-frequency voltage harmonics. More important, all SH components show a strong relationship with the DC-output voltage of the charger, which will change during a charging session. The presented method can be applied to other power-electronic devices as well and the findings are a step towards modeling the SH emission of FCSs.