A measurement port is required to quantify the voltage emissions.
This measurement device is connected in parallel to the
battery impedance emulating network. The measurement device
needs a high ohmic input to avoid a change of the emulation’s
input impedance. A 50 Ω source impedance of the measurement
port is required for RF measurement purposes. Therefore,
an impedance converter circuit was used for each traction
power line (T+ and T−). The 3 dB corner frequency of the
measurement port lies at ∼67 MHz, caused by the limited gainbandwidth
product of the operational amplifiers used. Fig. 10
shows a comparison of the CM and DM impedances of the HV
battery and its emulation.