Power Control of a Brushless Permanent Magnet Electric Machine for Exercise Bikes

This paper presents a power control structure for a brushless permanent magnet electric machine, where both generating and motoring operation modes using the same power stage coexist using a digital control scheme. In the generating mode, desired dynamic output such as constant power and constant torque can be achieved for use in an exercise bicycle, where the input power generated by pedaling is transferred into the battery in the form of electrical energy to provide braking resistance, known as the regenerative braking. The user controls the resistance via a closed-loop torque controller to the desired exercise, also the study uses three position Hall sensors instead of an expensive encoder, to perform the commutation and speed estimation. Both the theoretical derivation and experimental verification for the proposed control scheme are presented in this paper, which is implemented using a TI TMS320F240 digital signal processor. Copyright © 2002 IFAC