Estimation of radiated emissions of an automotive HV-inverter in a distributed system

EMC measurements according to CISPR 25 during a component´s development process in the automotive industry are expensive and time-consuming. In order to avoid these disadvantages alternative measurement methods are desired. One of such pre-compliance methods for estimating radiated emissions is the transfer function method. With this method radiated emissions can be calculated based on disturbance current measurements on a component´s harness. This is possible due to the correlation between disturbance currents and radiated field. In this contribution the transfer function method is applied to a distributed automotive system comprising an automotive high voltage inverter, line impedance stabilization networks and an electric machine emulation. In order to characterize the radiated emissions of such a system a combination of two transfer functions is used. The method of combined transfer functions will be introduced and applied to a simplified setup showing its applicability. In addition, an extended setup will be analyzed for meeting specifications of the automotive industry.