A Model of Electromagnetic Radiated Emissions for Dual Voltage Automotive Electrical Systems

In the automotive electromagnetic environment the impact of electromagnetic compatibility- (EMC) has to be considered since the design step, together with peifoimance and cost aspects, for obtaining reliable systems. Especially, for the new dual voltage vehicle electrical architectures where EMC oriented design is in a very early, stage and no suitable technical standard currently exists. In this paper a method for calculating the near field electromagnetic radiated emissions from a typical electrical load, used in a dual voltage automotive distributed architecture, is presented. The electrical load is an electrical drive with a 42/14V DC/DC step down converter devoted to fuel pumping. The method is based on the computation of the magnetic vector potential of a uniform current element and on the "image theory" and has been suitably validated by means of experiments. The calculation of electromagnetic radiated emissions requires only a time domain current measurement and does not present computational burden. The radiation model allows the prediction of radiated disturbance and the development of EMC oriented design and optimisation criteria of the vehicle electrical architecture. Moreover it can be used to define test methods for the development of suitable EMC technical standards for the new dual voltage vehicles.