Optimal Control and Design of Hybrid Electric Vehicles Including Bi-Directional DC-DC Converters

Abstract

The effect of using a bi-directional DC-DC converter on the hybrid electric vehicle performance is investigated. Dynamic programming is adopted as a control technique to determine the optimal drivetrain control signals, i.e. the power split as well as the DC-DC voltage ratio in order to minimize the overall fuel consumption. The proposed methodology is validated in the parallel hybrid topology. We will demonstrate that including a DC-DC converter and optimally controlling its operation yields a benefit of 24% fuel reduction, compared to a reference architecture, where a high voltage battery directly feeds the motor drive.