Transmission Design and Control Optimization of an Electric Vehicle Using Analytical Modeling Methods

Abstract

This paper introduces a framework to systematically optimize the design and control of an electric vehicle transmission, connecting powertrain sizing approaches with low-level gearbox design methods. To this end, we first create analytical models of the individual transmission components: gears, shafts, bearings, clutches, and synchronizers. Second, we construct a transmission by systematically configuring a topology with these components. Third, we integrate the composed transmission within a powertrain and vehicle model, and compute the minimum-energy control strategies and design, employing two solution algorithms, namely dynamic programming and exhaustive search, respectively, providing global optimality guarantees. Finally, we carry out the design and control optimization of a one- and two-speed transmission for a small electric family car, whereby we observe that a two-speed transmission can improve the energy consumption by 0.5% with respect to a one-speed transmission, whilst also satisfying the gradeability and performance requirements.