Predefined Speed Control of BLDC Motor - PowerPoint PPT Presentation

About This Presentation
Title:

Predefined Speed Control of BLDC Motor

Description:

This predefined speed control of BLDC motor runs a motor at user desired speed by using EEPROM for storing speed. It is an effective speed control method. – PowerPoint PPT presentation

Number of Views:1876

less

Transcript and Presenter's Notes

Title: Predefined Speed Control of BLDC Motor


1
ssss
Predefined Speed Control of BLDC Motor
2
Predefined Speed Control of BLDC Motor
Introduction
  • The aim of the project is to control the speed of
    a BLDC motor using a microcontroller with the
    help of SVPWM-technique. A brushless DC (BLDC)
    motor drive is characterized by higher
    efficiency, lower maintenance, and higher cost.
    Therefore, it is necessary to have a low-cost but
    effective BLDC motor controller. Based on the
    principle of PWM, speed of the motor can be
    controlled. 

http//www.edgefxkits.com/
3
Predefined Speed Control of BLDC Motor
Block Diagram
http//www.edgefxkits.com/
4
Predefined Speed Control of BLDC Motor
Hardware Components
  • 8051 series Microcontroller
  • LCD
  • Transformer
  • Voltage Regulator
  • Capacitors
  • Resistors
  • Diodes
  • BLDC Fan
  • EEPROM

http//www.edgefxkits.com/
5
Predefined Speed Control of BLDC Motor
Software Components
  • Keil compiler
  • Languages Embedded C or Assembly.

http//www.edgefxkits.com/
6
Predefined Speed Control of BLDC Motor
MICROCONTROLER
  • The AT89C52 is a low-power, high performance CMOS
    8-bit microcomputer with 8Kbytes of Flash
    programmable and erasable read only memory
    (PEROM).
  • The on-chip Flash allows the program memory to be
    reprogrammed in system or by a conventional
    nonvolatile memory programmer.

http//www.edgefxkits.com/
7
Predefined Speed Control of BLDC Motor
Features
  • 8K Bytes of In-System Reprogrammable Flash
    Memory
  • Endurance 1,000 Write/Erase Cycles
  • Fully Static Operation 0 Hz to 24 MHz
  • Three-level Program Memory Lock
  • 256 x 8-bit Internal RAM

http//www.edgefxkits.com/
8
Predefined Speed Control of BLDC Motor
BLDC Motor
  • The BLDC motor is an AC synchronous motor with
    permanent magnets on the rotor (moving part) and
    windings on the stator (fix part).
  • Permanent magnets create the rotor flux and the
    energized stator windings create electromagnet
    poles.
  • The rotor is attracted by the energized stator
    phase.

http//www.edgefxkits.com/
9
Predefined Speed Control of BLDC Motor
BLDC Motor
  • By using the appropriate sequence to supply the
    stator phases, a rotating field on the stator is
    created and maintained.
  • The lead between the rotor and the rotating field
    must be controlled to produce torque and this
    synchronization implies knowledge of the rotor
    position.

http//www.edgefxkits.com/
10
Predefined Speed Control of BLDC Motor
Principle of BLDC Motor
  • Frequency inverter used as Commutator.
  • Commutation depends on rotor position.
  • Speed control by motor voltage.
  • Angle between mmfs of a stator and rotor is fixed
    to 90 degree.
  • Motor behaves like a DC Motor.
  • No commutation occurs on spinning shaft.

http//www.edgefxkits.com/
11
Predefined Speed Control of BLDC Motor
Circuit Operation
The operation of the circuit can be explained in
three parts.
  • Control circuit
  • Motor driver and Gate driving circuit
  • Converter circuit

http//www.edgefxkits.com/
12
Predefined Speed Control of BLDC Motor
Control Circuit
  • Control circuit gives out the switching signals
    to the converter bridge.
  • A microcontroller is dedicated to generate the
    switching pulses.
  • The microcontroller is programmed to give out
    pulse according to SVPWMM technique.
  • Program is compiled in Keil software.

http//www.edgefxkits.com/
13
Predefined Speed Control of BLDC Motor
Control Circuit
  • The HEX code generated is loaded into the
    Microcontroller.
  • The controller used is AT89C52.
  • The controller is operated at 11.059 MHz
    frequency.

http//www.edgefxkits.com/
14
Predefined Speed Control of BLDC Motor
Motor Driver And Gate Driving Circuit
  • Instead of using an inverter and a regulator we
    have used a motor driver HW30A which acts as
    inverter to supply the voltage for the Motor.
  • HW30A is an inbuilt Inverter which is having
    Inverter circuit as well as MOSFET Driver
    circuit.
  • We are using this type of technique because of
    on using general inverter.

http//www.edgefxkits.com/
15
Predefined Speed Control of BLDC Motor
Motor Driver And Gate Driving Circuit
  • We are facing the difficulties like large Heat
    dissipation, so that this heat would cause a heat
    sinking problem which in turn results in the
    failure of the Inverter.
  • By using this motor driver the circuit complexity
    is reduced and the heat dissipation problem, is
    also reduced.

http//www.edgefxkits.com/
16
Predefined Speed Control of BLDC Motor
Converter Circuit
  • The converter circuit is provided by the Motor
    driver.
  • The D.C supply is fed through a bridge
    rectifier.
  • The switches in the Motor driver are turned ON
    and OFF as per the program.
  • The rectifier circuit is made of diodes.
  • The component used is IN4007 which is capable of
    blocking a reverse voltage of 1000 V DC and can
    carry a current of 10A continuous.

http//www.edgefxkits.com/
17
Predefined Speed Control of BLDC Motor
Converter circuit
  • All these components are placed on General PCB.
  • Control circuit and gate driving circuit
    components are soldered directly on the Pcb.
  • Whereas, the power components as connected with
    suitable connectors as they carry larger
    currents.

http//www.edgefxkits.com/
18
Predefined Speed Control of BLDC Motor
Working
  • The basic construction of a brushless dc consists
    of a fan blade attached to a permanent magnet
    rotor that surrounds the electromagnetic coils of
    the stator and associated control electronics.
  • A typical biphase brushless fan motor is made
    from a permanent magnet rotor assembly that
    surrounds four electromagnetic coils.
  • The coils work in pairs, with coils A and C
    forming one phase
  • and coils B and D the other phase.

http//www.edgefxkits.com/
19
Predefined Speed Control of BLDC Motor
Working Principle
  • A Halleffect sensor monitors rotor position,
    providing feedback to the embedded MCU for
    commutation, speed regulation, and fault
    detection.
  • Commutation between the two phase windings in the
    dc fan takes place electronically by alternately
    applying power to L1 and L2.
  • Dead zones between the power pulses limit
    current for speed control and helps minimize a
    cogging effect when the rotor magnets align with
    the stator coils.
  • The on and off power of the commutation period
    resembles the output from a pulse width
    modulator.

http//www.edgefxkits.com/
20
Predefined Speed Control of BLDC Motor
Working Principle
  • The MCU uses a PWM to control the period of the
    motor drivers and, thus set fan speed.
  • Feedback from the Hall sensor monitors actual fan
    rpm and indicate when communication should take
    place.
  • The MCU continuously monitors motor speed by
    measuring the output period of the Hall effect
    sensor.
  • A period that run shorter than the target length
    indicates motor speed is too fast.

http//www.edgefxkits.com/
21
Predefined Speed Control of BLDC Motor
Speed Control Of BLDC Motor
  • Pulse width modulation is a commonly used
    technique for controlling power to an electrical
    device.
  • The PWM switching frequency has to be much faster
    than what would affect the load.
  • Typically switchings have to be done several
    times a minute in an electric stove, 120 Hz in a
    lamp dimmer, from few kilohertz (kHz) to tens of
    kHz for a motor drive and well into the tens or
    hundreds of kHz in audio amplifiers and computer
    power supplies

http//www.edgefxkits.com/
22
Predefined Speed Control of BLDC Motor
Speed Control Of BLDC Motor
  • The term duty cycle describes the proportion of
    on time to the regular interval or period of
    time.
  • A low duty cycle corresponds to low power,
    because the power is off for most of the time.
  • Duty cycle is expressed in percent, 100 being
    fully on.
  • The main advantage of PWM is that power loss in
    the switching devices is very low.

http//www.edgefxkits.com/
23
Predefined Speed Control of BLDC Motor
Speed Control Of BLDC Motor
  • When a switch is off there is practically no
    current and when it is on, there is almost no
    voltage drop across the switch.
  • Power loss, being the product of voltage and
    current, is thus in both cases close to zero.
  • The desired speed can be obtained by changing the
    duty cycle.
  • The PWM in microcontroller is used to control
    the duty cycle of DC motor.
  • Average
    VoltageD Vin

http//www.edgefxkits.com/
24
Predefined Speed Control of BLDC Motor
SIMULATION RESULTS FOR VARIOUS PWM PULSES
  • The speed control technique employed here is
    pulse width modulation (PWM) technique.
  • The duty cycle determines the speed of the motor
  • Average voltage D
    Vin
  • The average voltage obtained for various duty
    cycles is also mentioned and as the duty cycle
    percentage decreases average voltage also
    decreases from the supply voltage.

http//www.edgefxkits.com/
25
Predefined Speed Control of BLDC Motor
SIMULATION RESULTS FOR VARIOUS PWM PULSES
  • Duty cycle is defined as the percentage of time
    the motor is ON.
  • Therefore, the duty cycle is given as
  • Duty Cycle 100 x Pulse
    Width/Period
  • Where,
  • Duty Cycle in ()
  • Pulse Width Time
    the signal is in the ON or high state(sec)
  • Period Time of one
    cycle (sec).

http//www.edgefxkits.com/
26
Predefined Speed Control of BLDC Motor
Applications
  • BLDC motors fulfill many functions originally
    performed by brushed DC motors.
  • Cost and control complexity prevents BLDC motors
    from replacing brushed motors completely in
    lowest cost areas.
  • High power BLDC motors are found in electric
    vehicles and hybrid vehicles.

http//www.edgefxkits.com/
27
Predefined Speed Control of BLDC Motor
Advantages
  • Voltage and current rating is high.
  • High speed can be achieved.
  • As there is no brushes it requires no servicing.
  • There is no sparking less electrical noise.

http//www.edgefxkits.com/
28
Predefined Speed Control of BLDC Motor
Conclusion
  • The hardware for closed loop control of BLDC
    motor using microcontroller is designed. By using
    the PWM technique speed of the BLDC motor was
    controlled and it was made to run at exactly
    entered speed. In future this hardware will be
    implemented and the speed control will be
    observed.

http//www.edgefxkits.com/
29
http//www.edgefxkits.com/
Write a Comment
User Comments (0)
About PowerShow.com