Calculated and Experimental Investigations of Resonant Step-Down DC-DC Converter Specifications for Electric Vehicles

The number of cars increases every year, so the ecology issues of transportation become more relevant from year to year. One of the solutions to the environmental problem is the gradual replacement of cars with internal combustion engines (ICE) by electric vehicles. However, electric transport is radically different in its design features from transport with ICE. One of such peculiarities is the necessity to supply the low-voltage electrical loads from the high voltage traction battery. The main aspects associated with the solution of this problem with the use of a special device - an isolating step-down DC-DC converter have been discussed. This paper complements the existing gaps in the following issues: power consumption by low-voltage equipment of the electric vehicle, the total load current changing, the energy balance of the auxiliary low-voltage battery (AB), the initial data for correct choice of circuit topology of converter. The results of calculated analysis and experimental dependence of the input/output characteristics of the step-down DC-DC converter under the urban traffic conditions are given. The requirements to the resonant step-down converters characteristics and positive energy balance to increase the auxiliary battery service life are formed as a result of the experimental data analysis.