Brushless DC Motor is a DC motor without brushes and commutator.
The structure is a permanent magnet AC synchronous motor, which uses power electronic technology (frequency converter) to input AC signals to the motor. But these AC signals are not sine waves, but bidirectional direct currents, and their waveforms are not limited. However, new vector control technology has used sine wave control for brushless DC motors, which has greatly improved torque ripple and low-speed performance .
The simpler structure has a magnet and two sets of (four) coils, and the two sets of coils switch on and off in turn. The magnet is the rotor and the coil is the stator. When the magnets are aligned with the coils, the coils are disconnected and the next coil is activated.
Compared with traditional brushed DC motors, brushless ones are more reliable.