Chopper control of DC disc-armature motor using power MOSFETs

A closed-loop current controller using power MOSFETs has been constructed for two-quadrant chopper control of a DC disc armature motor intended for use in an electric cycle. Theoretical analysis shows that lower energy requirements and higher efficiency are obtained using constant current, rather than voltage, control, and that approximately 30% of the energy expended in accelerating to maximum speed would be available for regeneration. The practical difficulties of using MOSFETs for motor control are discussed, and experimental results are presented which agree well with the theory.