Real-time, energy-efficient traction allocation strategy for the compound electric propulsion system
Journal
IEEE/ASME Transactions on Mechatronics
Journal Volume
22
Journal Issue
3
Pages
1371-1380
Date Issued
2017
Author(s)
Abstract
This paper presents the development of a novel compound electric propulsion system for the ground vehicle with the emphasis on real-time, energy-efficient traction control strategy. The proposed compound electric propulsion system employs an induction motor (IM) and two permanent-magnet synchronous motors (PMSMs) to provide traction forces for the front and rear wheels, respectively; such design is aimed to improve energy efficiency and vehicle dynamics performance of conventional electric vehicles (EVs) using IM traction systems by exploiting complementary power characteristics of IM and PMSMs and dynamic traction allocation on all wheels. In this study, a practical traction allocation method, which is based on the power fusion and instantaneous power minimization (IPM) concepts, is proposed to dynamically control the torque loads for the IM and PMSMs such that all motors can be operated in respective high-efficiency regions. The optimal operating points (torque, speed) of IM and PMSMs are searched off-line through the IPM process, and the efficiency maps of the IM and PMSMs are combined and transformed into an optimal efficiency map of the compound electric propulsion system. To verify the feasibility and efficacy of the proposed traction allocation strategy, hardware in the loop simulation experiments were conducted with an activemotor dynamometer, IM and PMSM, and a vehicle simulator. Experiments using the U.S. EPA Urban Dynamometer Driving Schedule (FTP-72) show that the compound electric propulsion system with the proposed traction allocation algorithm can reduce energy consumption by ∼24% as compared with the conventional IM traction system. In addition, the performance of the proposed traction allocationmethod is compared with alternative methods and analyzed under different control command update rates. © 2017 IEEE.
Other Subjects
Dynamometers; Electric lines; Electric machine control; Electric propulsion; Electric traction; Energy efficiency; Energy utilization; Ground vehicles; Induction motors; Magnets; Permanent magnets; Propulsion; Synchronous motors; Traction (friction); Traction control; Transportation; Vehicles; Wheels; Electric propulsion systems; Hardware in-the-loop simulation; Optimal operating point; Permanent magnet motor; Permanentmagnet synchronous motor (PMSMs); Reduce energy consumption; Road vehicle electric propulsion; Urban dynamometer driving schedules; Traction motors
Publisher
Institute of Electrical and Electronics Engineers Inc.
Type
journal article