Electronics- Inductive Output Transducersdenethor.wlu.ca/pc300/lectures/outbeam.pdf · Output Transducers DC motors Methods to reverse current to PM DC motor Electronics Inductive

Output TransducersDC motors

Methods to reverse current to PM DC motor

ElectronicsInductive Output Transducers

Terry Sturtevant

Wilfrid Laurier University

June 9, 2014

Terry Sturtevant Electronics Inductive Output Transducers


Methods to reverse current to PM DC motorSolenoid

Output transducers

also called “actuators”basically of two typesresistiveinductiveinductive loads require a few special considerations




Output transducers

also called “actuators”

basically of two typesresistiveinductiveinductive loads require a few special considerations




Output transducers

also called “actuators”basically of two types

resistiveinductiveinductive loads require a few special considerations




Output transducers

also called “actuators”basically of two typesresistive

inductiveinductive loads require a few special considerations




Output transducers

also called “actuators”basically of two typesresistiveinductive

inductive loads require a few special considerations




Output transducers

also called “actuators”basically of two typesresistiveinductiveinductive loads require a few special considerations




Solenoid

consists of a coil and plungercan be of either “push” or “pull” type“pull” type are much more common




Solenoid

consists of a coil and plunger

can be of either “push” or “pull” type“pull” type are much more common




Solenoid

consists of a coil and plungercan be of either “push” or “pull” type

“pull” type are much more common




Solenoid





Solenoid





Solenoid

plunger in




Solenoid




Solenoid

plunger out




Induced EMF

Quickly changing voltage across inductor produces inducedEMFinduced voltage tries to counteract change in currentcan produce big voltage spikesA diode across a coil will limit voltages to ≈ 0.7V .A zener diode can limit voltages the other way to about thezener voltage.




Induced EMF

Quickly changing voltage across inductor produces inducedEMF

induced voltage tries to counteract change in currentcan produce big voltage spikesA diode across a coil will limit voltages to ≈ 0.7V .A zener diode can limit voltages the other way to about thezener voltage.




Induced EMF

Quickly changing voltage across inductor produces inducedEMFinduced voltage tries to counteract change in current

can produce big voltage spikesA diode across a coil will limit voltages to ≈ 0.7V .A zener diode can limit voltages the other way to about thezener voltage.




Induced EMF

Quickly changing voltage across inductor produces inducedEMFinduced voltage tries to counteract change in currentcan produce big voltage spikes

A diode across a coil will limit voltages to ≈ 0.7V .A zener diode can limit voltages the other way to about thezener voltage.




Induced EMF

Quickly changing voltage across inductor produces inducedEMFinduced voltage tries to counteract change in currentcan produce big voltage spikesA diode across a coil will limit voltages to ≈ 0.7V .

A zener diode can limit voltages the other way to about thezener voltage.




Induced EMF

Quickly changing voltage across inductor produces inducedEMFinduced voltage tries to counteract change in currentcan produce big voltage spikesA diode across a coil will limit voltages to ≈ 0.7V .A zener diode can limit voltages the other way to about thezener voltage.




No diode to reduce induced EMF

I ≡ 0

Initially I = 0.





I = 0

+

-

Induced voltage tries to maintain I = 0.





I ?

Eventually current is established determined by resistance in circuit.





I ?

-

+

Induced voltage tries to maintain I at the previous value.





I = 0

Eventually current is reduced to I = 0.




Diode to reduce induced EMF

I ≡ 0

Initially I = 0.





I = 0

+

-

Induced voltage tries to maintain I = 0, but cannot exceed VZ .





I ?

Eventually current is established determined by resistance in circuit.





I ?

-

+

Induced voltage tries to maintain I but cannot exceed ≈ 0.7V .





I = 0

Eventually current is reduced to I = 0.




Current requirements

A solenoid requires more current to move plunger than to holdit.Maintaining current larger than necessary wastes power andproduces heat.Several options exist for adjusting current between moving theplunger and holding it.





A solenoid requires more current to move plunger than to holdit.

Maintaining current larger than necessary wastes power andproduces heat.Several options exist for adjusting current between moving theplunger and holding it.





A solenoid requires more current to move plunger than to holdit.Maintaining current larger than necessary wastes power andproduces heat.

Several options exist for adjusting current between moving theplunger and holding it.





A solenoid requires more current to move plunger than to holdit.Maintaining current larger than necessary wastes power andproduces heat.Several options exist for adjusting current between moving theplunger and holding it.




Series resistor




Series resistor




Series resistor

pick




Series resistor

pick

hold




Series resistor

hold




Multiple supplies




Multiple supplies

Vh

Vp




Multiple supplies

pick

Vh

Vp




Multiple supplies

hold

pick

Vh

Vp




Multiple supplies

holdVh

Vp




Multiple supplies

hold

pick

Vh

Vp

Vp > Vh




Pulse width modulation to limit current

pick

holdclock




Solenoids in action: Relays

A relay is a device for switching, which is based on a solenoid.The solenoid is used to open and close a switch.An internal spring returns the solenoid to its original position.





A relay is a device for switching, which is based on a solenoid.

The solenoid is used to open and close a switch.An internal spring returns the solenoid to its original position.





A relay is a device for switching, which is based on a solenoid.The solenoid is used to open and close a switch.

An internal spring returns the solenoid to its original position.





A relay is a device for switching, which is based on a solenoid.The solenoid is used to open and close a switch.An internal spring returns the solenoid to its original position.




Relay OFF

NO

commonNC




Relay ON

NO

commonNC




Permanent Magnet DC Motor (PMDC)Brushless DC motorsStepper motorsServo motors

DC motor types

Four main types of DC motorsPermanent MagnetBrushlessStepperServo





DC motor types

Four main types of DC motors

Permanent MagnetBrushlessStepperServo





DC motor types

Four main types of DC motorsPermanent Magnet

BrushlessStepperServo





DC motor types

Four main types of DC motorsPermanent MagnetBrushless

StepperServo





DC motor types

Four main types of DC motorsPermanent MagnetBrushlessStepper

Servo





DC motor types

Four main types of DC motorsPermanent MagnetBrushlessStepperServo





DC motor

PMDC (Permanent Magnet DC)uses permanent fixed magnetsarmature on shaft has electromagnetcommutator on shaft reverses current direction every halfrotationspeed controlled by currentcontinuous motion





DC motor

PMDC (Permanent Magnet DC)

uses permanent fixed magnetsarmature on shaft has electromagnetcommutator on shaft reverses current direction every halfrotationspeed controlled by currentcontinuous motion





DC motor

PMDC (Permanent Magnet DC)uses permanent fixed magnets

armature on shaft has electromagnetcommutator on shaft reverses current direction every halfrotationspeed controlled by currentcontinuous motion





DC motor

PMDC (Permanent Magnet DC)uses permanent fixed magnetsarmature on shaft has electromagnet

commutator on shaft reverses current direction every halfrotationspeed controlled by currentcontinuous motion





DC motor

PMDC (Permanent Magnet DC)uses permanent fixed magnetsarmature on shaft has electromagnetcommutator on shaft reverses current direction every halfrotation

speed controlled by currentcontinuous motion





DC motor

PMDC (Permanent Magnet DC)uses permanent fixed magnetsarmature on shaft has electromagnetcommutator on shaft reverses current direction every halfrotationspeed controlled by current

continuous motion





DC motor

PMDC (Permanent Magnet DC)uses permanent fixed magnetsarmature on shaft has electromagnetcommutator on shaft reverses current direction every halfrotationspeed controlled by currentcontinuous motion





Permanent magnet DC motor






























Brushless DC motor

uses fixed electromagnetsarmature on shaft has permanent magnetscontinuous motioncapable of holding one positionneed to sense positioncan use a hall effect sensor or sense induced voltage in unusedcoils





Brushless DC motor

uses fixed electromagnets

armature on shaft has permanent magnetscontinuous motioncapable of holding one positionneed to sense positioncan use a hall effect sensor or sense induced voltage in unusedcoils





Brushless DC motor

uses fixed electromagnetsarmature on shaft has permanent magnets

continuous motioncapable of holding one positionneed to sense positioncan use a hall effect sensor or sense induced voltage in unusedcoils





Brushless DC motor

uses fixed electromagnetsarmature on shaft has permanent magnetscontinuous motion

capable of holding one positionneed to sense positioncan use a hall effect sensor or sense induced voltage in unusedcoils





Brushless DC motor

uses fixed electromagnetsarmature on shaft has permanent magnetscontinuous motioncapable of holding one position

need to sense positioncan use a hall effect sensor or sense induced voltage in unusedcoils





Brushless DC motor

uses fixed electromagnetsarmature on shaft has permanent magnetscontinuous motioncapable of holding one positionneed to sense position

can use a hall effect sensor or sense induced voltage in unusedcoils





Brushless DC motor

uses fixed electromagnetsarmature on shaft has permanent magnetscontinuous motioncapable of holding one positionneed to sense positioncan use a hall effect sensor or sense induced voltage in unusedcoils





Brushless DC motor





Brushless DC motor





Brushless DC motor





Brushless DC motor





Brushless DC motor





Brushless DC motor





Stepper motor

uses fixed electromagnetsarmature on shaft has soft iron corei.e. no permanent magnetssimilar operation to brushless motorsdiscrete stepsdrive electronics controls speed and directionhalf-stepping is possiblecan hold in position





Stepper motor

uses fixed electromagnets

armature on shaft has soft iron corei.e. no permanent magnetssimilar operation to brushless motorsdiscrete stepsdrive electronics controls speed and directionhalf-stepping is possiblecan hold in position





Stepper motor

uses fixed electromagnetsarmature on shaft has soft iron core

i.e. no permanent magnetssimilar operation to brushless motorsdiscrete stepsdrive electronics controls speed and directionhalf-stepping is possiblecan hold in position





Stepper motor

uses fixed electromagnetsarmature on shaft has soft iron corei.e. no permanent magnets

similar operation to brushless motorsdiscrete stepsdrive electronics controls speed and directionhalf-stepping is possiblecan hold in position





Stepper motor

uses fixed electromagnetsarmature on shaft has soft iron corei.e. no permanent magnetssimilar operation to brushless motors

discrete stepsdrive electronics controls speed and directionhalf-stepping is possiblecan hold in position





Stepper motor

uses fixed electromagnetsarmature on shaft has soft iron corei.e. no permanent magnetssimilar operation to brushless motorsdiscrete steps

drive electronics controls speed and directionhalf-stepping is possiblecan hold in position





Stepper motor

uses fixed electromagnetsarmature on shaft has soft iron corei.e. no permanent magnetssimilar operation to brushless motorsdiscrete stepsdrive electronics controls speed and direction

half-stepping is possiblecan hold in position





Stepper motor

uses fixed electromagnetsarmature on shaft has soft iron corei.e. no permanent magnetssimilar operation to brushless motorsdiscrete stepsdrive electronics controls speed and directionhalf-stepping is possible

can hold in position





Stepper motor

uses fixed electromagnetsarmature on shaft has soft iron corei.e. no permanent magnetssimilar operation to brushless motorsdiscrete stepsdrive electronics controls speed and directionhalf-stepping is possiblecan hold in position





Single stepping





Single stepping





Single stepping





Single stepping





Single stepping





Single stepping





Half stepping





Half stepping





Half stepping





Half stepping





Half stepping





Half stepping





Half stepping





Half stepping





Half stepping





Half stepping





Half stepping





Half stepping





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedback

internal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronics

uses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to control

default width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)

longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one direction

shorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other direction

pulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)

often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree travel

digital input does not have induced EMF problemsinternal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problems

internal electronics handles that





Servo motor

PMDC motor with position sensing and feedbackinternal electronicsuses a digital pulse to controldefault width keeps motor stationary (e.g. 1.5 ms)longer pulse makes motor rotate in one directionshorter pulse makes motor rotate in the other directionpulse must be repeated periodically (e.g. every 20 ms)often limited to less than 360 degree traveldigital input does not have induced EMF problemsinternal electronics handles that





Induced EMFs and motors

Same problem as with solenoidscan produce big voltage spikesDiodes across the coils can be used the same way






Same problem as with solenoids

can produce big voltage spikesDiodes across the coils can be used the same way






Same problem as with solenoidscan produce big voltage spikes

Diodes across the coils can be used the same way






Same problem as with solenoidscan produce big voltage spikesDiodes across the coils can be used the same way





dpdt switchbipolar supplyH bridge





dpdt switch

bipolar supplyH bridge





dpdt switchbipolar supply

H bridge





dpdt switchbipolar supplyH bridge




DPDT switch

V+

V−

common (to RL)

common (to RL)




DPDT switch

V+

V−

common (to RL)

common (to RL)

6

6




DPDT switch

V+

V−

common (to RL)

common (to RL)

?

?




Bipolar supply

V+

V−

RL




Bipolar supply

V+

V−

RL

-




Bipolar supply

V+

V−

RL

�




H bridge

V+

V−

RL1

2

3

4




H bridge

V+

V−

RL1

2

3

4-




H bridge

V+

V−

RL1

2

3

4�


Electronics- Inductive Output Transducersdenethor.wlu.ca/pc300/lectures/outbeam.pdf · Output Transducers DC motors Methods to reverse current to PM DC motor Electronics Inductive

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