Range Extension Control of a Three-Wheel Electric Vehicle Prototype Based on Aggregation and Distribution

Abstract

This paper presents an approach for the range extension control of a three-wheel electric vehicle prototype. By using the torque distribution vector to aggregate motor speeds, the physical model of the vehicle is mapped to an aggregation-and-distribution model (AaDM), which possesses the passivity property. Based on the AaDM, motion control and energy optimization can be designed separately. In particular, a speed controller was designed for the system to operate in the automatic cruise mode. A disturbance observer was designed to operate in the human driving mode. In this study, the conditions for the controllers were obtained to sufficiently ensure the L₂ stability of the control system. The conditions can be checked conveniently without establishing the dynamical equation of the overall system. Under the practically reasonable assumption on motor parameters, the analytical solutions of the optimal torque distribution ratios and d-axis currents were approximately derived in this study. Various test scenarios were considered to validate the proposed control systems. The test results show that in either operation modes, the system can prevent wheel slip, thereby simultaneously improving motion control and energy minimization.