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Mathematical Problems in Engineering
Volume 2016, Article ID 2548967, 14 pages
Research Article

Design of a Load Torque Based Control Strategy for Improving Electric Tractor Motor Energy Conversion Efficiency

1School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, No. 5, Jinhua South Road, Beilin District, Xi’an 710048, China
2Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, No. 48, Xiyuan Road, Jianxi District, Luoyang 471003, China

Received 12 January 2016; Revised 23 March 2016; Accepted 31 March 2016

Academic Editor: Luis J. Yebra

Copyright © 2016 Mengnan Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In order to improve the electrical conversion efficiency of an electric tractor motor, a load torque based control strategy (LTCS) is designed in this paper by using a particle swarm optimization algorithm (PSO). By mathematically modeling electric-mechanical performance and theoretical energy waste of the electric motor, as well as the transmission characteristics of the drivetrain, the objective function, control relationship, and analytical platform are established. Torque and rotation speed of the motor’s output shaft are defined as manipulated variables. LTCS searches the working points corresponding to the best energy conversion efficiency via PSO to control the running status of the electric motor and uses logic and fuzzy rules to fit the search initialization for load torque fluctuation. After using different plowing forces to imitate all the common tillage forces, the simulation of traction experiment is conducted, which proves that LTCS can make the tractor use electrical power efficiently and maintain agricultural applicability on farmland conditions. It provides a novel method of fabricating a more efficient electric motor used in the traction of an off-road vehicle.