Date

12-2009

Degree Name

BS in Electrical Engineering

Department

Electrical Engineering Department

Advisor

Ali Shaban

Abstract

The project is a circuit that will basically supply current from the battery to the different stator coils at opportune moments. With a hall-effect sensor on the shaft as a feedback to a microcontroller, I was able to toggle switches based on the position of the shaft at the moments where we would be using as little power as possible. The operation of the control circuit works similar to a stepper motor; it takes a signal from the microcontroller that is sent to some FET drivers, which in turn sends signals to the FETs to open or close as the shaft is rotating. Since the stator coils are set at a certain angle apart from each other, it was an advantage to know where the starting point was, and extrapolate where every other magnet was with respect to the coils by putting the hall-effect sensor in line with one set of permanent magnets. This way, current was only sent to the stator coils when it was necessary to turn the motor. The idea was that we could conserve power by drawing from the battery less often, but made little progress in the final testing stages in conjunction with the motor. We ran into many problems with the inductor coils on the stator due to a communication error, so the core for the inductors needed to be completely redesigned.

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