ABSTRACT
This chapter explains brushless direct current (BLDC) motors and drives. The BLDC motor operates in such a way as to emulate the operation of a shunt DC motor with brushes, or a permanent-magnet DC motor. The chapter describes the alternating current imposed on the stator windings in the BLDC must be switched in synchronism with the rotor position in order to maintain field-orientation, or optimal stator current and rotor flux interaction, as the commutator, brushes, and windings act to provide in a DC machine. It discusses the advantages, disadvantages, and fundamentals of operation of the permanent-magnet BLDC motor. The chapter presents equations that can be used in a computer program simulation model for a BLDC motor and drive. Sensorless BLDC motor control refers to the operation of the BLDC without its usually required rotor position sensor. The surface-mounted magnet BLDC back-electromotive force waveshape is often dependent on the magnetic orientation of the magnets.
