Hybrid Electric Vehicles, 2nd Edition

15HEV Component Sizing and Design Optimization

15.1 Introduction

One key research and development topic for hybrid electric vehicles (HEVs) is an innovative hybrid powertrain, whose parameters must be tuned for the desired performance of the hybrid vehicle [1]. A hybrid powertrain comprises electric motors, power electronics converters, energy storage devices such as batteries and ultracapacitors, and sophisticated controllers, in addition to such classical components as internal combustion engines (ICEs), transmissions, clutches, drive shafts, and differentials. Therefore, a hybrid powertrain is much more complicated than a conventional powertrain. The component sizing and system prototyping of a hybrid powertrain is difficult because of the many design options and the rapidly developing technologies in the automotive industries [2]. The cost and performance of the designed hybrid powertrain are determined by the chosen configuration and hundreds of design variables and parameters. A parametric design method can be used to determine hybrid vehicle component sizes. Example design variables include the power ratings of the fuel converter (ICE), motor controller, number of battery cells, final drive ratio, and control strategy parameters. The parametric design can yield a hybrid vehicle with a better performance than the baseline vehicle. The overall design is unlikely to be optimal, but it can be used as a rough design for further optimization so as to maximize fuel economy and ...