Stator (Outer Ring): Stacked silicon steel sheets with embedded three-phase windings (A/B/C), generating a rotating magnetic field by passing alternating current.
Rotor (Inner Ring): Permanent magnets (neodymium iron boron/ferrite), providing a fixed magnetic field; no windings, no brushes.
Position Sensors: Hall effect sensors (3, distributed 120°) or back EMF detection (without Hall effect sensors), providing real-time feedback on rotor position and commutation signals to the controller.
Controller (Electronic Speed Controller, ESC): The core "brain," containing an MCU and MOSFET drivers, switching the three-phase current sequentially according to the Hall effect signals to achieve commutation, speed regulation, forward/reverse rotation, and protection.
Working Principle (Electronic Commutation, No Physical Contact)
Initial State: Hall effect sensors detect the position of the rotor permanent magnet and send a signal to the controller.
Stator Field Establishment: The controller drives MOSFETs to energize two phase windings of the stator (e.g., A+, B-), generating a magnetic field in a fixed direction.
Rotor Following: The stator magnetic field and the rotor permanent magnets repel each other at their like poles and attract each other at their unlike poles, causing the rotor to rotate 60°.
Electronic Commutation (Key): After the rotor rotates 60°, the Hall effect signal changes, and the controller switches the energizing phase sequence (e.g., A+, C-), causing the stator magnetic field to rotate 60°, pulling the rotor to continue rotating.
Continuous Operation: Repeating the "60° commutation" cycle, the stator forms a continuously rotating magnetic field, and the rotor rotates synchronously; speed regulation = adjusting the PWM duty cycle/frequency, changing the magnetic field strength/speed.
Simple Analogy: Brushed motors use "mechanical levers" to switch current; brushless motors use "electronic switches" for precise commutation, with no friction throughout the entire process.
