brushless dc motor

1. A SEMINAR ON
BRUSHLESS DC MOTOR
SUBMITTED TO;
Mr. KULDEEP BHARDWAJ
Mr. DINESH TIWARI
SUBMITTED BY;
VINAY SINGH
E.E. 3rd year
1404620904

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

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. CONVENTIONAL DC MOTOR

5. PMBLDC MOTOR

6. 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

7. 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

8. 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.

9. HALL EFFECT

10. 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

11. FEATURES CONVENTIONAL DC
MOTOR
PMBLDC MOTOR
Maintenance High low
Commutation method Mechanical contact
between brushes &
commutator.
Electronic switching using
power semiconductor
devices i.e.,
transistor,MOSFET
Detecting method Automatically detected by
brushes
Rotor position can be
detected by using sensor
i.e., Hall sensor, optical
sensor
controllable Speed controllable is
difficult
Speed can be easily
controllable, so that it is
possible to have very high
speed

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

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

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

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