Electric Motors

To propel an electric vehicle, electricity must be converted to mechanical force. Electric motors use current flowing through wires to create magnetic fields that interact with other magnetic fields in the motor to create motion.

DC Motors

DC motors are electro-mechanical machines which take DC inputs to generate torque. These machines include Brushed DC, Brushless DC machines (BLDC), and homopolar machines among others. While some use mechanical commutators like brushes, some DC machines commutate electrically based on the rotor position.

Brushed DC Motor

Brushed DC Motors are the conventional hobbyist motor and come in two main varieties: Permanent Magnet Based (PMDC) and Field-Winding Based (FWDC). They use mechanical brushes to commutate the the flow of current through the rotor to generate a torque. Because of this, they are easy to control, and do not require a position sensor to track the rotation of the motor. For the PMDC machine, the flux generated by the rotor interacts with the permanent magnet flux to generate torque. For the FWDC machine, the permanent magnets are replaced by another set of coils which generate the stator flux. This allows the machines to operate at high speeds using flux weakening techniques.

For FSAE applications, Brushed DC machines can reduce system complexity; however, at higher power levels, these machines have low efficiencies and must have regular maintenance of brushes. In addition, these machines have relatively low torque and power density which can increase system mass and cause packaging issues. For these reasons, they are not commonly used in FSAE powertrains.

Brushless DC Motor

Known for their trapezoidal waveforms. Typically uses an encoder to track the rotation of the motor.

AC Synchronous Motors

Known for their sine waves. Typically uses a resolver to track the rotation of the motor. Can also use sensorless feedback based on the back EMF of the motor.