Optimization of permanent magnet brushless machine for biomechanical energy harvesting applications

For electrical power generation over long durations, it would be desirable to harvest energy normally wasted during ordinary human activities such as walking. It is a challenge, however, to produce substantial electricity from walking. Most energy harvesting research has concentrated on generating electricity from the compression of the shoe sole, with the best devices generating 0.8 W, reported by Paradiso (2005). This thesis addresses a noteworthy departure, which is a spring-loaded backpack that harnesses the vertical movements of a load to generate electricity during normal walking. A mechanical apparatus can be used to convert the linear motion to a rotary one. Based on characteristics of the motion, a brushless permanent magnet generator is chosen as the candidate for this energy conversion rather than the linear permanent magnet generator used previously in the literature. The split ratio, i.e. the ratio of the stator bore diameter to the stator outer diameter, is considered as one of the important parameters in designing cylindrical permanent magnet brushless machines. The objective function of motor constant per unit volume is studied in this work. The optimal split ratio is investigated analytically for motors having overlapping and non-overlapping windings, and accounting for the influence of the air gap flux distribution, the stator tooth-tips and the end-windings. It is shown that the split ratio can notably influence the motor constant (i.e. torque efficiency) of a permanent magnet brushless motor.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2010

Author dc:creator

• Sayyah, Arash

Contributors dc:contributor

• Chapman, Patrick L.

• Optimization
• permanent magnet brushless machine
• energy harvesting

Statement dc:rights

• Copyright 2010 Arash Sayyah

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/16490

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F16490