New Time-Domain Tuning of RF Filter for Evaluating Immunity of Vehicle DC Charging Communication

In the Combined Charging System (CCS) for DC charging of vehicles, Power line communication (PLC) is used in combination with the control pilot (CP) as communication system between the charging station and the electric vehicle (EV). This communication has been shown to be susceptible to conducted interference that is emitted on the charging cables. With the automotive industry shifting towards higher voltage system with 800 V on the DC-bus, fast-switching on-board converters are installed in order to ensure compatibility of the 800 V vehicle with 400 V DC EVSE - thus increasing the EMI threat. Filtering is often needed to provide sufficient protection. This paper presents a way to emulate and tailor an RF filter (that has a frequency dependent attenuation) towards a sufficient attenuation of an anticipated time-domain repetitive switching noise. A tailored current pulse model is used to emulate the inverter noise. The impact of theoretical filters is emulated by shaping the switching test pulse in an arbitrary wave generator settings. The PLC signaling response of the attenuated pulse is checked in a vehicle charging test jig. With this method, elaborate and time consuming in-vehicle filter testing with physical filters is evaded. Therefore, software tailoring of the filter performance is an attractive option that allows quick and flexible filter tuning.