Controlled Rectiers EE-463 STATIC POWER CONVERSION-I

EE-463 STATIC POWER CONVERSION-I

Controlled Recti�ersOzan Keysan

keysan.me

O�ce: C-113 • Tel: 210 7586

1 / 46

http://keysan.me/

Thyristor Recti�ers

2 / 46

Thyristor Recti�ersHVDC Transmission Systems

2 / 46


DC Motor Drives

2 / 46


DC Motor Drives

Traction Applications

2 / 46


DC Motor Drives

Traction Applications

Industrial Loads (Welding, Heating etc)

2 / 46


3 / 46

Thyristor Recti�ersGeneral Schematic

3 / 46


4 / 46

Thyristor Recti�ersOperating Quadrants

Capable of supplying negative Vd (Q4, Inversion) 4 / 46

Simple Circuits

5 / 46

Simple CircuitsThyristor with R load

Can you plot the voltage output?

5 / 46

Simple CircuitsThyristor with R load

6 / 46

Simple CircuitsThyristor with RL load

Can you plot the voltage output?

7 / 46

Simple CircuitsThyristor with RL load

8 / 46

Simple CircuitsLoad with DC Source

Can you plot the voltage output?9 / 46

Load with DC Source

10 / 46

Thyristor with RL load

but let's add a freewheeling diode

11 / 46

Thyristor with freewheeling diode

12 / 46

Single Phase Thyristor Recti�er

13 / 46

Single Phase Thyristor Recti�erIdeal Case

Can you plot the output voltages? 14 / 46

It is identical to diode recti�er with α = 0

15 / 46

What about with a large �ring angle?

16 / 46

How can you calculate the average voltage?

17 / 46


V = cos(α)dα2 V s2

–√

π

17 / 46


Diode recti�er


–√

π

α = 0 →

17 / 46


Diode recti�er


–√

π

α = 0 →

α < π/2 → V d > 0

17 / 46


Diode recti�er


–√

π

α = 0 →

α < π/2 → V d > 0

α > π/2 → V d < 0

17 / 46

Operating Modes

18 / 46

Power Flow

19 / 46

Power Flow

P = ∫ p(t)dt1

T

19 / 46

Power Flow

P = ∫ p(t)dt1

T

P = ∫ (t)dt = 0.9 cos(α)Id1

Tvd VsId

19 / 46

Line Current

Shifted by , but still a square waveα

20 / 46

Line Current

Shifted by , but still a square wave

Harmonics, THD, I1?

α

20 / 46

Line Current

Shifted by , but still a square wave

Harmonics, THD, I1?

What about PF, DPF?

α

20 / 46

Real Power, Apparent Power

21 / 46

Real Power, Apparent Power

MultiSim 21 / 46

https://www.multisim.com/content/kRQKTtG5FCPiYqpQ89p5jD/controlled-rectifier

Single Phase Recti�er with Resistive Load

Voltage Waveform?

22 / 46


23 / 46


Average Voltage?

23 / 46


V = (1 + cos(α))dαV s2

–√

π24 / 46

Single Phase Recti�er with R-L Load (ContinuousCurrent)

25 / 46

Single Phase Recti�er with R-L Load (ContinuousCurrent)

26 / 46

Single Phase Recti�er with R-L Load (DiscontinuousCurrent)

27 / 46

Single Phase Recti�er with Freewheeling Diode

28 / 46


Can you plot the voltage, current waveform?

28 / 46


Can you plot the voltage, current waveform?

What are the advantages, disadvantages?28 / 46

How can you make this circuit cheaper?

29 / 46

Full Bridge Half Controlled Recti�er

30 / 46


D1, D2 works as freewheeling diodes

30 / 46


D1, D2 works as freewheeling diodes

Vd cannot be negative30 / 46

Full Bridge Half Controlled Recti�erAlternative (Same Output)

D3 can be removed (depending on load, and thyristor gate signals)31 / 46

Commutation

32 / 46

CommutationWith source side inductance (Ls)

32 / 46

Commutation

33 / 46

CommutationCan you plot the voltage and current outputs?

33 / 46

CommutationE�ect on the output voltage

34 / 46


= (cos(α) − cos(α+ u)) = 2ωAu 2–√ Vs LsId

34 / 46


= (cos(α) − cos(α+ u)) = 2ωAu 2–√ Vs LsId

cos(α+ u) = cos(α) −2ωLsId

2–√ Vs

34 / 46

CommutationVoltage drop due to commutation

35 / 46


Δ = =VduAu

π

2ωLsId

π

35 / 46


Δ = =VduAu

π

2ωLsId

π

= 0.9 cos(α) −Vd Vs2ωLsId

π

35 / 46

ExampleMohan Ex. 6.1

36 / 46

Practical Thyristor Converter

37 / 46


Consider a case as a DC motor drive

37 / 46


Continuous Conduction (id is always > 0)

38 / 46



Average voltage with commutation?

38 / 46



Average voltage with commutation?

≈ 0.9 cos(α) −Vd Vs

2ωLsId,min

π38 / 46



Average Current?

39 / 46



Average Current?

=Id−Vd Ed

rd39 / 46


What happens if Id is small?

40 / 46


Discontinuous Conduction

41 / 46


Discontinuous Conduction

42 / 46

Inverter Mode

43 / 46

Inverter Mode90 < Firing Angle < 180

43 / 46


Average power<0 (Power �ows from DC to AC)

Only with active power source on DC side 43 / 46


44 / 46

Inverter ModeThyristor Voltage

45 / 46


Extinction Angle ( )γ = 180 − (α + u)

45 / 46


Extinction Angle ( )

Extinction time should be larger than thyristor turn-o� time ( )!

γ = 180 − (α + u)

tq 45 / 46

You can download this presentation from:keysan.me/ee463

46 / 46

http://keysan.me/ee463

Controlled Rectiers EE-463 STATIC POWER CONVERSION-I

Documents

Transcript of Controlled Rectiers EE-463 STATIC POWER CONVERSION-I