ABSTRACT
This chapter reviews the basics of direct current (DC) motor and various control theories. The DC motor offers a standard model for electro-mechanical systems, and the operational principles constitute the basics of the whole motor control theory: back EMF, torque generation, current control, torque-speed control, field-weakening, etc. DC motors are popularly used since torque/speed controllers are simple, and their costs are much lower than the inverter costs. However, DC motors are inferior to alternating current (AC) motors in power density, efficiency, and reliability. The DC field is generated by either field winding or permanent magnets (PMs). Armature winding is wound on a shaft. An electric motor is a machine that converts electrical oscillation into the mechanical oscillation. Although a DC source is supplied to the machine, an alternating current is developed in the armature winding by brush and commutator, i.e., the armature current polarity changes through a mechanical commutation made of brush and commutator.
