6-1

Chapter 6

Thyristor Converters

• Controlled conversion of ac into dc

6-2

Thyristor Converters

• Two-quadrant conversion

6-3

Primitive circuits with thyristors

6-4

Thyristor Triggering

• ICs available

6-5

Full-Bridge Thyristor Converters

• Single-phase and three-phase

6-6

Single-Phase Thyristor Converters

• Two groups with two thyristor each

6-7

1-Phase Thyristor Converter Waveforms

• Assuming zero ac-side inductance

6-8

Average DC Output Voltage

• Assuming zero ac-side inductance

6-9

Input Line-Current Waveforms

• Harmonics, power and reactive power

6-10

1-Phase Thyristor Converter

• Finite ac-side inductance; constant dc output current

6-11

Thyristor Converter Waveforms

• Finite ac-side inductance

6-12

Thyristor Converter: Discontinuous Mode

• This mode can occur in a dc-drive at light loads

6-13

Thyristor Converter Waveforms

• PSpice-based simulation

6-14

Thyristor Converter Waveforms: Discontinuous Conduction Mode

• PSpice-based simulation

6-15

DC Voltage versus Load Current

• Various values of delay angle

6-16

Thyristor Converters: Inverter Mode

• Assuming the ac-side inductance to be zero

6-17

Thyristor Converters: Inverter Mode

• Family of curves at various values of delay angle

6-18

Thyristor Converters: Inverter Mode

• Importance of extinction angle in inverter mode

6-19

Thyristor Converters: Inverter Mode

• Waveforms at start-up

6-20

3-Phase Thyristor Converters

• Two groups of three thyristors each

6-21

3-Phase Thyristor Converter Waveforms

• Zero ac-side inductance; purely dc current

6-22

DC-side voltage waveforms assuming zero ac-side inductance

6-23

Input Line-Current Waveform

• Zero ac-side inductance

6-24

Input line-current waveforms assuming zero ac-side inductance

6-25

Three-Phase Thyristor Converter

• AC-side inductance is included

6-26

Current Commutation Waveforms

• Constant dc-side current

6-27

Input Line-Current Waveform

• Finite ac-side inductance

6-28

Input Line-Current Harmonics

• Finite ac-side inductance

6-29

Input Line-Current Harmonics

• Typical and idealized

6-30

Three-Phase Thyristor Converter

• Realistic load

6-31

Thyristor Converter Waveforms

• Realistic load; continuous-conduction mode

6-32

Thyristor Converter Waveforms

• Realistic load; discontinuous-conduction mode

6-33

Thyristor Inverter

• Constant dc current

6-34

Thyristor Inverter Waveforms

• Finite ac-side inductance

6-35

Thyristor Inverter

• Family of curves at various values of delay angle

6-36

Thyristor Inverter Operation

• Importance of extinction angle

6-37

Thyristor Converters: Voltage Notching

• Importance of external ac-side inductance

6-38

Limits on Notching and Distortion

• Guidelines

6-39

Thyristor Converter Representation

• Functional block diagram