IE1206 Embedded Electronics - KTH...Ex6 Le10 LC-osc, DC-motor, CCP PWM LP-filter Trafo Le12 Ex7...

Preview:

Citation preview

  • IE1206 Embedded Electronics

    Transients PWM

    Phasor jω PWM CCP CAP/IND-sensor

    Le1

    Le3

    Le6

    Le8

    Le2

    Ex1

    Le9

    Ex4 Le7

    Written exam

    William Sandqvist william@kth.se

    PIC-block Documentation, Seriecom Pulse sensorsI, U, R, P, serial and parallel

    Ex2

    Ex5

    Kirchhoffs laws Node analysis Two-terminals R2R AD

    Trafo, Ethernet contactLe13

    Pulse sensors, Menu program

    Le4

    KC1 LAB1

    KC3 LAB3

    KC4 LAB4

    Ex3Le5 KC2 LAB2 Two-terminals, AD, Comparator/Schmitt

    Step-up, RC-oscillator

    Le10Ex6 LC-osc, DC-motor, CCP PWM

    LP-filter TrafoLe12 Ex7 Display

    Le11

    •••• Start of programing task

    •••• Display of programing task

  • William Sandqvist william@kth.se

    Transformer

  • William Sandqvist william@kth.se

    Voltage ratio

    2

    1

    2

    1

    2211 d

    d

    d

    d

    N

    N

    U

    U

    tNU

    tNU

    =

    Φ=Φ=

    N1 : N2

  • William Sandqvist william@kth.se

    Ideal transformer I0 = 0

    N1⋅I0 = N1⋅ I1 – N2⋅ I2

    Magnetisig current I0 ≈ 0 is smallcompared to the work currents I1 and I2. The transformer itself has a high inductance.

  • William Sandqvist william@kth.se

    Current ratio

    2

    1

    2

    1

    1

    2

    2211

    0021 )0,(

    N

    N

    U

    U

    I

    I

    IUIU

    IPPP

    =≈

    ⇒⋅=⋅==

    N1 : N2

  • William Sandqvist william@kth.se

    Eddy current losses

    Eddy currents – currents inside the iron core is prevented with lacquered ( = isolation ) sheet metal.

  • William Sandqvist william@kth.se

    E I -core

    • EI-core is very economical to manufacture!

  • William Sandqvist william@kth.se

    E I -core

  • William Sandqvist william@kth.se

    Toroid

    Toroid core has a low leakage field – so it will not disturb nearby electronics!

    How do one wind such a transformer?

  • William Sandqvist william@kth.se

    Automatic Winding of toroidal core

  • William Sandqvist william@kth.se

  • William Sandqvist william@kth.se

    Transformer (15.4)

  • William Sandqvist william@kth.se

    Transformer (15.4)

    2

    1

    1

    2

    2

    1

    2

    1

    =

    ⇒=

    I

    I

    U

    U

  • William Sandqvist william@kth.se

    Transformer (15.4)

    2

    1

    1

    2

    2

    1

    2

    1

    =

    ⇒=

    I

    I

    U

    U

    8102,010010 1111 =⋅−=⇒=−⋅− UUIR

  • William Sandqvist william@kth.se

    Transformer (15.4)

    2

    1

    1

    2

    2

    1

    2

    1

    =

    ⇒=

    I

    I

    U

    U

    8102,010010 1111 =⋅−=⇒=−⋅− UUIR

    42

    8

    2

    112 ==⋅= UU

  • William Sandqvist william@kth.se

    Transformatorn (15.4)

    2

    1

    1

    2

    2

    1

    2

    1

    =

    ⇒=

    I

    I

    U

    U

    8102,010010 1111 =⋅−=⇒=−⋅− UUIR

    42

    8

    2

    112 ==⋅= UU 4,01

    212 =⋅= II

  • William Sandqvist william@kth.se

    Transformer (15.4)

    2

    1

    1

    2

    2

    1

    2

    1

    =

    ⇒=

    I

    I

    U

    U

    8102,010010 1111 =⋅−=⇒=−⋅− UUIR

    42

    8

    2

    112 ==⋅= UU 4,01

    212 =⋅= II

    Ω=== 104,0

    4

    2

    22 I

    UR

  • William Sandqvist william@kth.se

  • William Sandqvist william@kth.se

    2

    2

    2

    121

    2

    2

    2

    2

    1

    21

    2

    22

    1

    1

    1

    2

    22

    1

    11

    RN

    NR

    I

    U

    N

    N

    IN

    N

    UN

    N

    I

    U

    I

    UR

    I

    UR

    =

    ====

    RN

    N ⋅

    2

    2

    1

    Transforming impedances

  • William Sandqvist william@kth.se

    2

    2

    2

    121

    2

    2

    2

    2

    1

    21

    2

    22

    1

    1

    1

    2

    22

    1

    11

    RN

    NR

    I

    U

    N

    N

    IN

    N

    UN

    N

    I

    U

    I

    UR

    I

    UR

    =

    ====

    RN

    N ⋅

    2

    2

    1

    Transforming impedances

  • William Sandqvist william@kth.se

    Ex. Transforming impedances

    A transformer has the voltage ratio 240V/120V.

    We have two capacitors 1µF and 16 µF. How should one connect to get 5 µF ?

  • William Sandqvist william@kth.se

    Ex. Transforming impedances

    )4/(

    12

    1

    1

    221

    2

    CCZ

    CZ

    ωω

    ω

    =⋅=

    ⇒=

    A transformer has the voltage ratio 240V/120V.

    We have two capacitors 1µF and 16 µF. How should one connect to get 5 µF ?

  • William Sandqvist william@kth.se

    Ex. Transforming impedances

    )4/(

    12

    1

    1

    221

    2

    CCZ

    CZ

    ωω

    ω

    =⋅=

    ⇒=

    16 Fµ4 Fµ

    A transformer has the voltage ratio 240V/120V.

    We have two capacitors 1µF and 16 µF. How should one connect to get 5 µF ?

  • William Sandqvist william@kth.se

  • William Sandqvist william@kth.se

    Series and parallel connection of inductors

    (Ex. 15.6) Assuming that none of the coils parts magnetic lines of force with each other but are completely independent components, they can be treated series and parallel inductors just as if they were resistors.

    H36

    4444

    4

    64444

    4

    ERS =+

    +⋅+

    +⋅+

    =L

  • William Sandqvist william@kth.se

    Series and parallel connection of inductors?We have previously studied serial and parallel coils as if they were completely independent components that do not share magnetic lines with each other.

    We are now treating coils with interconnected flow

    ??

  • Inductive coupling

    William Sandqvist william@kth.se

    d

    du r i

    t

    ϕ= ⋅ +

    A portion of the flow in the coil 1 is interconnected with flow from the coil 2.

    11 1 1 1 1 1 2

    d

    du r i i L i M

    t

    ϕ ϕ= ⋅ + = ⋅ + ⋅In same way: 2

    2 2 2 2 2 2 1

    d

    du r i i L i M

    t

    ϕ ϕ= ⋅ + = ⋅ + ⋅

    Induction

  • Inductive coupling

    William Sandqvist william@kth.se

    1 21 1 1 1

    2 12 2 2 2

    d d

    d dd d

    d d

    i iu r i L M

    t ti i

    u r i L Mt t

    = ⋅ + +

    = ⋅ + +

    1 1 1 1 1 2

    2 2 2 2 2 1

    j j

    j j

    U r I L I MI

    U r I L I MI

    ω ωω ω

    = ⋅ + += ⋅ + +

    jω-method:

    ± M is called mutual inductance

    21LL

    Mk =

    Coupling factor:

    The coupling factor indicates how much of the flow a coil has in common with another coil

    An ideal transformer has coupling factor k = 1 (100%)

  • Series with mutual inductance

    William Sandqvist william@kth.se

    Series connection has the same current

    212111 LLL IMjILjU ωω ±= 121222 LLL IMjILjU ωω ±=

    1 2 1 2 12 21

    1 2( )L L L LI I I U U U M M M

    U I j L M L Mω= = = + = = ⇒

    = ⋅ ± + ±

    1 2( 2 )U

    j L L MI

    ω= + ±

    11121 LL IUML 22212 LL IUML

    Derive:

  • Series with mutual inductance

    William Sandqvist william@kth.se

    MLLLTOT 221 ++= MLLLTOT 221 −+=

    Series connection has the same current I1 = I2 =I

    M can can contribute or counter act to the flow, this gives ±sign. Therefore, coil winding polarity is usually indicated by adot convention in schematics.

    M-dot M-dot M-dot M-dot

  • ”Dot” convention

    William Sandqvist william@kth.se

    An increasing current in to a dot results in induced voltages with directions that would give increasing currents out of other dots.

  • ”Dot” convention

    William Sandqvist william@kth.se

    An increasing current in to a dot results in induced voltages with directions that would give increasing currents out of other dots.

  • In parallel with mutual inductance

    William Sandqvist william@kth.se

    MLL

    MLLLTOT 221

    221

    −+−⋅=

    MLL

    MLLLTOT 221

    221

    ++−⋅=

    TOTL TOTL

    Parallel connected coils Antiparal conected coils

  • Ex. 15.7 Series connection

    William Sandqvist william@kth.se

    51 =L 102 =L 153 =L

    212 =M 323 =M

    113 =M

    [H]

  • Ex. 15.7 Series connection

    William Sandqvist william@kth.se

    51 =L 102 =L 153 =L

    212 =M 323 =M

    113 =M

    [H]

    LTOT =

    L1 + M12 – M13 +

    L2 + M12 – M23 +

    L3 – M23 – M13 =

    = 5 +2 –1 + 10 + 2 – 3 + 15 –3 –1 = 26 [H]

  • William Sandqvist william@kth.se

  • Measuring the mutual inductance?

    William Sandqvist william@kth.se

    +TOTL −TOTL

    MLLLTOT 221 ++=+ MLLLTOT 221 −+=−

  • Measuring the mutual inductance?

    William Sandqvist william@kth.se

    +TOTL −TOTL

    MLLLTOT 221 ++=+ MLLLTOT 221 −+=−

    4−+ −= TOTTOT LLM

  • Variometer (to an antique radio)

    William Sandqvist william@kth.se

    )(

    221αfM

    MLLLTOT=

    ±+=

  • William Sandqvist william@kth.se

  • A bad actuator can become a good sensor

    William Sandqvist william@kth.se

    1906

  • The industry's "rugged" position sensor

    William Sandqvist william@kth.se

  • Differential transformer

    William Sandqvist william@kth.se

    LVDT Linear Variable Differential Transformer

    The secondary coils are connected in series but with opposite polarity – when the core is in the middle U = 0.

    core

    primary coil

    secondary coilsecondary coil

  • LVDT design

    William Sandqvist william@kth.se

  • William Sandqvist william@kth.se

    The output voltage is relatively high – it makes this a popular sensor …

    LVDT principle

  • LVDT probe

    Output signal changes phase180°°°° exactly when the core pass the middle point.

    William Sandqvist william@kth.se

    A XOR-gate kan indicate this change.

  • A LVDT probe can keep track on that the thicknes is correct.

    Guess application?

    It is important to ensure that the ATM does not distribute "double" bills …

    William Sandqvist william@kth.se

  • William Sandqvist william@kth.se

    Periodic differential transformer

    Renywell Spherical encoder

    LVDT-principel witin a core, and then keep track on how many cores that have passed.

    A similar sensor?

  • William Sandqvist william@kth.se

Recommended