Brushless DC Motor - PowerPoint PPT Presentation

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Brushless DC Motor

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Classical DC motors are no doubt good and simple but inefficient in some ways.• Although dc motors possess good control characteristics and ruggedness, their performance and applications are inhibited due to sparking and commutation problems.• The Permanent Magnet Brushless DC (PMBLDC) motor is able to overcome the limitations mentioned above and satisfy the requirements of a variable speed drive – PowerPoint PPT presentation

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Title: Brushless DC Motor


1
NSPEES 2012
  • BRUSHLESS D.C MOTORS
  • Prepared by

  • Deepak Kumar Mohapatra
  • Pijush
    Kumar Banerjee

2
Contents
  • Abstract.
  • Introduction.
  • Basics of a motor.
  • Classification.
  • Brushed motors.
  • BLDCM.
  • Working procedure.
  • Applications.
  • Advantages.
  • Disadvantages.
  • Conclusion.
  • Reference.

3
Abstract
  • Permanent magnet (PM) brushless DC motors (BLDCM)
    are generated by virtually inverting the stator
    and rotor of PM DC motors.
  • These motors are actually fed by rectangular AC
    waveform.
  • The advantage is the removal of brushes, leading
    to eliminate many problems associated with
    brushes.
  • Another advantage is the ability to produce a
    larger torque because of the rectangular
    interaction between current and flux.

4
Introduction
  • Classical DC motors are no doubt good and simple
    but inefficient in some ways.
  • Although dc motors possess good control
    characteristics and ruggedness, their performance
    and applications are inhibited due to sparking
    and commutation problems.
  • The Permanent Magnet Brushless DC (PMBLDC) motor
    is able to overcome the limitations mentioned
    above and satisfy the requirements of a variable
    speed drive.

5
MOTOR
  • MOTOR
  • gtgt Converts electrical energy to mechanical
    energy.
  • ORIGIN...
  • gtgt Nicola Tesla introduces electric motor
  • in December 1889.
  • gtgt He identifies the principle of rotating
    magnetic field.

6
Main parts of brushed motor...
  • Commutator
  • gtgt Facilitate collection of current from the
    armature conductors.
  • Brush
  • gtgt Collects current from the commutator.

7
Classification
8
BLDCM
  • Has no brushes and commutators.
  • Rotation of the rotor depends on the accurate
    position with stator.
  • 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.

9
Working of BLDCM
  • 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.

10
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.

11
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
  • FILB
  • F Force
  • B Magnetic Field
  • L Length of Conductor
  • I Current in Conductor
  • Torque in Motor
  • T IBA sin ?
  • A LW
  • L Length of Winding
  • W Width of Winding

12
Simulation Of BLDCM
13
Output Of Simulation
14
Speed Torque Characteristics
15
Working Procedure
  • 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.

16
Pros
  • In BLDC motor PM are on the rotor
    electromagnets are on the stator controlled by
    software. Thus the advantages are
  • Because of computer control it is more precise
    more efficient.
  • There is no sparking less electrical noise.
  • Voltage and current rating is high.
  • High speed can be achieved.
  • As there is no brushes it requires no servicing.
  • It has longer life.
  • Low Radio Frequency Interference and
    electromagnetic Interference.

17
Cons
  • Requires Complex Drive Circuitry.
  • Requires additional Sensors.
  • Expensive.
  • Some designs require manual labor.
    (Hand wound Stator Coils)

18
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
Reference
  • http//en.wikipedia.org/wiki/Alternator
  • http//en.wikipedia.org/wiki/Electric_motor
  • http//www.basler.com
  •  Thompson, Sylvanus P., Dynamo-Electric
    Machinery, A Manual for Students of Electro
    techniques, Part 1, Collier and Sons, New York,
    1902
  • White, Thomas H.,"Alternator-Transmitter
    Development (1891-1920)". EarlyRadioHistory.us.
  • S.M.L.Kabir, R.Shuttle worth, Brushless Exciter
    Model.

20
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