Brushless DC Motor(BLDC) A BLDC is simply a normal dc motor turned inside out,that means the coil is on the out side and the magnets are inside The stator consists of several coils which current is led through Creating a magnetic field that makes the rotor turns

1. Brushless DC Motors
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2. Motor Basics
• What is a motor
Converts electrical energy into kinetic energy
• How it works

3. Brushless DC Motor(BLDC)
Principles
• A BLDC is simply a normal dc motor turned inside out,
that means the coil is on the out side and the magnets
are inside
• The stator consists of several
coils which current is led through
Creating a magnetic field that
makes the rotor turns

4. Construction
• Stator consists of stacked steel
laminations with windings placed in
the slots that are axially cut along the
inner periphery
• Rotor is made of permanent magnet and can vary from two to
eight pole pairs with alternate North (N) and South (S) poles.
Ferrite magnets and Rare earth alloy magnets are used in rotor

5. Unlike a brushed DC motor, the commutation
of a BLDC motor is controlled electronically.
It is important to know the rotor position in order
to understand which winding will be energized
following the energizing sequence.
Rotor position is sensed by different ways some
of them are
1) Hall sensors
2) Optical encoders

6. Hall Sensors
When a magnetic field applied to a system with electric current a
hall voltage Perpendicular to the field and to current is generated.
This was discovered by Edwin Hall in 1879.

7. How it works
• Halls Sensors sense
the position of the
coils
• The Decoder
Circuit turns
appropriate switches
on and off
• The voltage
through the specific
coils turns the motor

8. Torque generation
Fig 2
Fig 1
Fig 3

10. TORQUE/SPEED CHARACTERISTICS

11. Advantages
• Increased Reliability & Efficiency
• Longer Life
• Elimination of Sparks from Commutator
• Reduced Friction
• Faster Rate of Voltage & Current

12. Disadvantages
• Requires Complex Drive Circuitry
• Requires additional Sensors
• Higher Cost
• Some designs require manual labor
(Hand wound Stator Coils)

13. Applications
Consumer: Hard Drives, CD/DVD
Drives, PC Cooling Fans, toys, RC
airplanes, air conditioners

14. Medical: Artificial heart,
Microscopes, centrifuges,
Arthroscopic surgical tools, Dental
surgical tools and Organ transport
pump system.

15. Vehicles: electronic power steering,
personal electric vehicles
Airplanes: an electric self launching
sailplane, flies with a 42kW DC/DC
brushless motor and Li-Ion batteries and
can climb up to 3000m with fully charged
cells

16. Closing thoughts
Given the existing availability and firstcost
penalty, BLDC technology will find greatest
acceptance wherever its performance
advantage over a wide speed range can be
combined with its excellent variable-speed
capabilities. we can expect this combination to
yield an efficiency improvement of at least
30 percent over single-speed AC induction
motors
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