Post on 03-Jan-2022
EE-463 STATIC POWER CONVERSION-I
Controlled Recti�ersOzan Keysan
keysan.me
O�ce: C-113 • Tel: 210 7586
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Thyristor Recti�ers
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Thyristor Recti�ersHVDC Transmission Systems
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Thyristor Recti�ersHVDC Transmission Systems
DC Motor Drives
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Thyristor Recti�ersHVDC Transmission Systems
DC Motor Drives
Traction Applications
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Thyristor Recti�ersHVDC Transmission Systems
DC Motor Drives
Traction Applications
Industrial Loads (Welding, Heating etc)
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Thyristor Recti�ers
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Thyristor Recti�ersGeneral Schematic
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Thyristor Recti�ers
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Thyristor Recti�ersOperating Quadrants
Capable of supplying negative Vd (Q4, Inversion) 4 / 46
Simple Circuits
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Simple CircuitsThyristor with R load
Can you plot the voltage output?
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Simple CircuitsThyristor with R load
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Simple CircuitsThyristor with RL load
Can you plot the voltage output?
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Simple CircuitsThyristor with RL load
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Simple CircuitsLoad with DC Source
Can you plot the voltage output?9 / 46
Load with DC Source
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Thyristor with RL load
but let's add a freewheeling diode
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Thyristor with RL load
but let's add a freewheeling diode
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Thyristor with freewheeling diode
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Thyristor with freewheeling diode
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Single Phase Thyristor Recti�er
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Single Phase Thyristor Recti�er
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Single Phase Thyristor Recti�erIdeal Case
Can you plot the output voltages? 14 / 46
It is identical to diode recti�er with α = 0
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It is identical to diode recti�er with α = 0
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What about with a large �ring angle?
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What about with a large �ring angle?
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How can you calculate the average voltage?
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How can you calculate the average voltage?
V = cos(α)dα2 V s2
–√
π
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How can you calculate the average voltage?
Diode recti�er
V = cos(α)dα2 V s2
–√
π
α = 0 →
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How can you calculate the average voltage?
Diode recti�er
V = cos(α)dα2 V s2
–√
π
α = 0 →
α < π/2 → V d > 0
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How can you calculate the average voltage?
Diode recti�er
V = cos(α)dα2 V s2
–√
π
α = 0 →
α < π/2 → V d > 0
α > π/2 → V d < 0
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Operating Modes
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Power Flow
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Power Flow
P = ∫ p(t)dt1
T
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Power Flow
P = ∫ p(t)dt1
T
P = ∫ (t)dt = 0.9 cos(α)Id1
Tvd VsId
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Line Current
Shifted by , but still a square waveα
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Line Current
Shifted by , but still a square wave
Harmonics, THD, I1?
α
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Line Current
Shifted by , but still a square wave
Harmonics, THD, I1?
What about PF, DPF?
α
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Real Power, Apparent Power
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Real Power, Apparent Power
MultiSim 21 / 46
Single Phase Recti�er with Resistive Load
Voltage Waveform?
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Single Phase Recti�er with Resistive Load
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Single Phase Recti�er with Resistive Load
Average Voltage?
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Single Phase Recti�er with Resistive Load
V = (1 + cos(α))dαV s2
–√
π24 / 46
Single Phase Recti�er with R-L Load (ContinuousCurrent)
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Single Phase Recti�er with R-L Load (ContinuousCurrent)
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Single Phase Recti�er with R-L Load (DiscontinuousCurrent)
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Single Phase Recti�er with Freewheeling Diode
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Single Phase Recti�er with Freewheeling Diode
Can you plot the voltage, current waveform?
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Single Phase Recti�er with Freewheeling Diode
Can you plot the voltage, current waveform?
What are the advantages, disadvantages?28 / 46
How can you make this circuit cheaper?
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Full Bridge Half Controlled Recti�er
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Full Bridge Half Controlled Recti�er
D1, D2 works as freewheeling diodes
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Full Bridge Half Controlled Recti�er
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
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CommutationWith source side inductance (Ls)
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CommutationWith source side inductance (Ls)
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Commutation
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CommutationCan you plot the voltage and current outputs?
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CommutationCan you plot the voltage and current outputs?
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CommutationE�ect on the output voltage
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CommutationE�ect on the output voltage
= (cos(α) − cos(α+ u)) = 2ωAu 2–√ Vs LsId
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CommutationE�ect on the output voltage
= (cos(α) − cos(α+ u)) = 2ωAu 2–√ Vs LsId
cos(α+ u) = cos(α) −2ωLsId
2–√ Vs
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CommutationVoltage drop due to commutation
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CommutationVoltage drop due to commutation
Δ = =VduAu
π
2ωLsId
π
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CommutationVoltage drop due to commutation
Δ = =VduAu
π
2ωLsId
π
= 0.9 cos(α) −Vd Vs2ωLsId
π
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ExampleMohan Ex. 6.1
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Practical Thyristor Converter
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Practical Thyristor Converter
Consider a case as a DC motor drive
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Practical Thyristor Converter
Consider a case as a DC motor drive
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Practical Thyristor Converter
Continuous Conduction (id is always > 0)
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Practical Thyristor Converter
Continuous Conduction (id is always > 0)
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Practical Thyristor Converter
Continuous Conduction (id is always > 0)
Average voltage with commutation?
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Practical Thyristor Converter
Continuous Conduction (id is always > 0)
Average voltage with commutation?
≈ 0.9 cos(α) −Vd Vs
2ωLsId,min
π38 / 46
Practical Thyristor Converter
Continuous Conduction (id is always > 0)
Average Current?
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Practical Thyristor Converter
Continuous Conduction (id is always > 0)
Average Current?
=Id−Vd Ed
rd39 / 46
Practical Thyristor Converter
What happens if Id is small?
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Practical Thyristor Converter
Discontinuous Conduction
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Practical Thyristor Converter
Discontinuous Conduction
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Inverter Mode
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Inverter Mode90 < Firing Angle < 180
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Inverter Mode90 < Firing Angle < 180
Average power<0 (Power �ows from DC to AC)
Only with active power source on DC side 43 / 46
Inverter Mode90 < Firing Angle < 180
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Inverter ModeThyristor Voltage
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Inverter ModeThyristor Voltage
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Inverter ModeThyristor Voltage
Extinction Angle ( )γ = 180 − (α + u)
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Inverter ModeThyristor Voltage
Extinction Angle ( )
Extinction time should be larger than thyristor turn-o� time ( )!
γ = 180 − (α + u)
tq 45 / 46