DC-DC converter design for power distribution systems in electric vehicles using calorimetric loss measurements

In this contribution, a uni-directional converter is proposed which supplies the EV's safety-low voltage grid of 14 V DC directly from the drive battery voltage level of V_batt = 250...370 V. The converter consists of two power stages which are a hard-switching SiC boost converter and a softswitching resonant converter. Special attention is paid to the accurate loss modelling of the converter, where frequency-depending winding losses, magnetic core losses, and semiconductor switching losses are considered. The core and winding losses were validated by calorimetric measurements, which results are in good accordance with the simulations. As final result, a converter peak efficiency of 98.2% was achieved.