Evaluation of radiated EMI in 42 V vehicle electrical systems by FDTD simulation

In this paper, a full 3-D numerical scheme based on the finite-difference time-domain method is used to predict the electromagnetic (EM) radiated interference generated by 42-V vehicle power electronic driven electrical loads. An experimental setup has been arranged in order to validate the proposed simulation tool. To this aim, the features of a semi-anechoic EM chamber have been exploited in order to operate in a shielded test site for the measurement of near-field radiated emissions. Two different 3-D geometrical configurations of realistic vehicle installations of the loads are studied. A comparative analysis among measured and computed results is performed. A good agreement between simulated and measured data is obtained. The proposed approach is suitable for the prediction of radiated EM interference generated by dc/dc converters and, particularly, by dual-voltage vehicle electric plants. In fact, due to the presence of complicated layout, the prediction of EM emissions can be a useful task in order to evaluate the EM compatibility (EMC) compliance from the design stage. Furthermore, with the growing market penetration of the “More Electric Vehicle” (MEV) concept in designing new vehicle electrical architectures, low-cost test methods for EMC assessments and suitable technical standard requirements have to be introduced. The proposed simulation tool can be usefully adopted to this aim. As an important advantage, it requires only a current measurement in the time domain. Such measurement does not need the use of a special test site or of a radiated field measurement setup.