Key characteristics of the Variable Speed Brushless DC motor  :

• Synchronous, external commutation

• No brush noise, durable, robust

• Flat speed versus torque characteristics

• Position/Speed Servo

How it works:

The Brushless DC motor   does not operate directly off a DC voltage source. The Brushless DC motor   has a rotor with permanent magnets, a stator with windings and commutation that is performed electronically. Typically three Hall sensors are used to detect the rotor position and commutation is performed based on Hall sensor inputs. The DC Brushless motor is clean, fast and efficient, and creates no sparks, making it a safer choice in explosive environments. The linear current/torque relationship results in smoother acceleration. In sensorless control, back EMF zero crossing is used for commutation. This motor type has a longer life than Brushed DC motor  s.

Typical requirements for Variable Speed Brushless DC motor  s:

Input:

• Typically torque, speed, position, and/or direction

• Inputs can be analog voltage, potentiometer, switches, or digital communications

Control:

• Basic I/O for firmware bit-bang for 6-step

• 3 phase PWMs for hardware PWM

• Comparators for speed sensing in sensorless control, over-current detection

• Capture/Compare/PWM or input captures for speed sensing

Feedback:

• Hall-effect sensors, optical encoder, tachometer, or back-EMF voltage

Driver:

• 3 phase Inverter