The disadvantages of the Brushless DC Motor over the AC motors are:
higher maintenance (due to brushes)
more expensive
In addition to the above the Brushless DC Motors have the same advantages over AC motors but they also have more advantages over Brushed DC Motors
lower maintenance (no brushes)
even higher starting torque ( Due to rare earth magnets)
even higher efficiency (over 90%) on sub fractional motors
even more compact design
better heat dissipation
lower noise
This paper presents the design of an axial-field permanent-magnet (PM) brushless dc motor drive for use on an electric bicycle. Details of the motor and the electronic converter are given. Performance analysis using the finite element method is briefly discussed. A prototype motor was constructed for verifying the actual performance. Good correlation between the theoretical and experimental results has been obtained. Test results confirmed the feasibility of the proposed motor design.
