Electrified Automotive Power train Architecture Using Composite DC-DC Converters

Electrified Automotive Power train Architecture Using Composite DC-DC Converters

 Abstract:

In a hybrid or electric vehicle powertrain, a boost dc-dc converter enables reduction of the size of the electric machine and optimization of the battery system. Design of the powertrain boost converter is challenging because the converter must be rated at high peak power, while eciency at medium to light load is critical for the vehicle system performance. By addressing only some of the loss mechanisms, previously proposed eciency improvement approaches oer limited improvements in size, cost and eciency trade-os. This paper shows how all dominant loss mechanisms in automotive powertrain applications can be mitigated using a new boost composite converter approach. In the composite dc-dc architecture, the loss mechanisms associated with indirect power conversion are addressed explicitly, resulting in fundamental eciency improvements over wide ranges of operating conditions. Several composite converter topologies are presented and compared to state-of-the-art boost converter technologies. It is found that the selected boost composite converter results in a decrease in the total loss by a factor of two to four for typical drive cycles. Furthermore, the total system capacitor power rating and energy rating are substantially reduced, which implies potentials for significant reductions in system size and cost.

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