This document discusses brushless DC motors. It explains that brushless DC motors are synchronous motors that use electronic commutation instead of brushes to create the rotating magnetic field. Hall sensors detect the rotor position and the commutation circuit controls current to the stator windings accordingly. Brushless DC motors have advantages like higher efficiency, longer life, and no sparking compared to brushed DC motors. They find applications in devices like electric vehicles, industrial equipment, appliances and consumer electronics.

1. Brushless Dc motor
Presented by:
Sanjeet kumar
Registration No.-1308143
Branch: Electrical & Electronics Engineering

2. Brushless Dc Motor
• Brushless DC Motors are a type of
synchronous motor.
 magnetic fields generated by the stator and rotor
rotate at the same frequency
 no slip
 Has no brushes and commutators.
 Rotation of the rotor depends on the accurate
position with stator.

3. • Detected by Hall Sensor,
mounted on rotor, shifted at
60º or 120º phase shift.
• Electronic commutation
used to vary the PWM duty-
cycle for speed control,
using software.
• Available in single-phase,
2-phase, and 3-phase
configurations

4. BLDC Motor Stator

5. BLDC Motor Rotors

6. Working of Brushless dc motor
 As there is no commutator ,the
current direction of the conductor
on the stator controlled
electronically.
 Rotor consists the permanent
magnet where as stator consist a no.
of windings. Current through these
winding produces magnetic field
and force.
 Hall sensor used to determine the
position during commutation.

7. Commutation of BLDCM…
 Brushless DC motor requires external commutation circuit to
rotate the rotor.
 Rotor position is very important.
 HALL SENSOR senses the position of the coil accurately.

8. Working Procedure
• When electric current passes through a coil in a magnetic field, the magnetic force
produces a torque which turns the motor.
• Force in Motor:
• F=ILB
• F = Force
• B = Magnetic Field
• L = Length of Conductor
• I = Current in Conductor
• Torque in Motor:
• T = IBA sin θ
• A = LW
• L = Length of Winding
• W = Width of Winding

9. Hall-Effect
• If a current-carrying conductor is kept in a
magnetic field, the magnetic field exerts a
force on the moving charge carriers, tending to
push them to one side of the conductor,
producing a measurable voltage difference
between the two sides of the conductor.

10. Hall-Effect Sensors
• Need 3 sensors to determine the position of the
rotor
• When a rotor pole passes a Hall-Effect sensor,
get a high or low signal, indicating that a
North or South pole

11. Transverse Sectional View of Rotor

12. Commutation Sequence
• Each sequence has
 one winding energized positive (current into the
winding)
 one winding energized negative (current out of the
winding)
 one winding non-energized

13. Torque-Speed Characteristic

15. Advantage
 In BLDC motor PM are on the rotor &
electromagnets are on the stator
controlled by software. Thus the
advantages are:
1. Because of computer control it is more
precise & more efficient.
2. There is no sparking & less electrical
noise.
3. Voltage and current rating is high.
4. High speed can be achieved.
5. As there is no brushes it requires no
servicing.
6. It has longer life.
7. Low Radio Frequency Interference and
electromagnetic Interference.

16. Disadvantage
 Requires Complex Drive Circuitry.
 Requires additional Sensors.
 Expensive.
 Some designs require manual labor.
(Hand wound Stator Coils)

17. Applications
• PMBLDC motors are
increasingly being used in a wide
spectrum of applications:
• domestic equipments,
• automobiles
• information technology equipment
• industries
• public life appliances
• transportation
• aerospace, defence equipments, power
tools, toys, vision and sound equipments
• medical and health care equipment
ranging from microwatts to megawatts.

19. Presented By:
Sanjeet Kumar
sanjeetkumar2101@gmail.com
+91-8968143473