Torque Control Strategies for AWD Electric Vehicles

[摘要] There is a fundamental shift occurring in the design of passenger vehicles for NorthAmerican markets. While for decades automotive manufacturers have relied on internalcombustion engines burning fossil fuels, the early 21st century has seen a departure fromconventional thinking about powertrain design towards two new design paradigms: hybridelectric vehicles (HEVs), and fuel cell vehicles (FCVs).Hybrid electric vehicles incorporate a high power electric motor and an electrical storagesystem which are used for motive power in addition to their conventional internal combustionengine (ICE). Fuel cell vehicles use a stack of individual cells to produce electric powerwhich is then used in an electric motor to move the vehicle. They are generally fueled by astream of high purity hydrogen, and produce only water as an emission. Both vehicle typesuse electric motors as an integral component in their configuration.The objective for this thesis is to propose a control strategy for the traction motors of a hybridor electric vehicle. In particular, it addresses the question of how to split torque between twoonboard electric motors while considering the efficiency, stability, and traction of the vehicle.This work is based upon two hybrid vehicles: a Chevrolet Equinox converted to a Fuel CellHEV, and a Chrysler Pacifica converted to an internal combustion engine HEV.A torque control strategy is recommended that focuses on improved efficiency whileaddressing vehicle stability, and traction control. The strategy also incorporates powertraincomponent protection. Simulations indicate that the manner in which torque is split betweenthe motors can have a large impact on the total efficiency of the powertrain; greater than 7%improvement fuel economy is projected by using an intelligent torque control system over aiiiFTP-75 drive cycle. It is recommended that this work be extended to incorporate regenerativebraking and a more thorough analysis of vehicle stability and drivability.

[发布机构] University of Waterloo

[关键词] Mechanical Engineering