Assessment of a Multi-Functional Converter System for Traction Electric Drives

The introduction of strict regulations in terms of air pollution is pushing automotive industry and heavy equipments vehicles manufacturers to integrate electric drives into the powertrain. To overcome the limitations on maximum battery voltage, a DC-DC bidirectional boost converter stage between the battery and the inverter is widely adopted by manufacturers. However, these converters are bulky, expensive and impact on the system efficiency. For this reason, Multi-Functional Converter Systems (MFCS) have been introduced in order to avoid the voltage boost stage and take advantage of the electric motor and the inverter to integrate the boost converter within these two components. This paper carries out a comparison between a traditional architecture, with a DC-DC boost converter stage, and a MFCS, to determine the best solution in terms of efficiency, weight and encumbrance.