Terminal Model Application For Characterizing Conducted Emi In Boost Converter System

A terminal model is a common method to create equivalent models of boost converters in order to predict conducted emissions. In this paper, a characterization board was designed to measure the voltages across and currents flowing into the input side of a DC-DC boost converter automatically by changing the load conditions using the relays as switches. After the equivalent source was determined, the induced noise voltage at the test load was compared to that predicted by the model. The results indicate that the agreement with the direct measurement is quite good up to 100 MHz when the load is within the characterization range. The model is able to correctly predict the conducted emission of the converter in situations quite different from the characterization conditions, for example when an EMI filter is added.