Energy Optimal Control of Motor Drive System for Extending Ranges of Electric Vehicles

Abstract

The short driving range per charge of electric vehicle is a critical shortcoming hindering its popularization and application. This article proposes an in-vehicle energy optimal control (EOC) to improve the efficiency of the motor drive system. This article first builds a vehicle's longitudinal dynamics model and a motor drive system's efficiency model. Then, a Lagrange-Euler-based optimal control theory is formulated with detailed proof. Based on the vehicle dynamics model, a cost function is constructed by considering the energy consumption and speed demand. Combining the cost function and the Lagrange-Euler-based optimal control theory, an in-vehicle EOC is proposed. The idea of the in-vehicle EOC is mainly to make the motor drive system operate in the high efficiency region as much as possible, which results in longer driving ranges. The in-vehicle EOC is validated on a co-simulation platform and the results show it outperforms the model predictive control method.