A New Method of Utilizing Ultra-Capacitor Energy Sources in Hybrid Electric Vehicles Over a Wide Speed Range


In previous research, the authors introduced a unique method to directly use an ultra-capacitor (UC) without using a dc/dc converter as the peak traction power source of the (hybrid) electric vehicles. That method works well in urban driving cycles where the motor speed is usually lower than half rated speed. Considerable energy efficiency improvement was achieved compared to conventional methods using a dc/dc converter as the UC interface. However, the acceleration and braking at higher speeds with only ultra-capacitor sources still require a dc/dc converter. In this paper, a new methodology is proposed to directly use UC to provide peak power up to the full vehicle speed. Two UC charging options are also proposed. The overall cost reduction compared to the previous methods is considerable. Detailed simulations verify the effectiveness of the proposed methodology. Lab validation is ongoing.

Meeting Name

22nd Annual IEEE Applied Power Electronics Conference and Exposition (2007: Feb. 25-Mar. 1, Anaheim, CA)


Electrical and Computer Engineering

Keywords and Phrases

Automobile Electronic Equipment; Automobile Parts And Equipment; Automobiles; Capacitance; Capacitors; Conservation; Cost Reduction; Costs; Dielectric Devices; Efficiency; Electric Automobiles; Electric Currents; Electric Equipment; Electric Traction; Electric Vehicles; Energy Storage; Exhibitions; Finance; Industrial Economics; Power Electronics; Profitability; Speed; Ultrasonics; Vehicles; Applied (CO); Charging (Materials); Conventional Methods; DC/DC Converters; Driving Cycles; Energy Efficiency Improvement (EEI); Hybrid Electric Vehicles (HEVs); Motor Speeds; New Methods; Peak Powers; Traction Power; Ultracapacitor (UC); Vehicle Speeds; Wide Speed Range; Energy Efficiency

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


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© 2007 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Mar 2007