Line commutated converters, also known as rectifier circuits, use natural commutation to convert alternating current into direct current. They can be uncontrolled rectifiers, controlled rectifiers, or semi-controlled rectifiers. A half wave controlled rectifier with a resistive load produces an output voltage equal to the peak input voltage multiplied by the duty cycle, while one with an inductive load has a higher effective output voltage due to freewheeling diodes. Full wave control circuits use two SCRs or a triac to rectify each half cycle, operating in either a midpoint or bridge configuration to produce direct current without or with freewheeling diodes.

1. Line Commutated Converters
or
Rectifier Circuits
Converters which work on the principle of
natural commutation are called line-commutated
converters

2. Classification
• Uncontrolled rectifiers
• Controlled rectifiers or full controlled rectifiers
• Semi-controlled rectifiers or half controlled
rectifiers

3. Half wave controlled rectifier with
resistive load

4. • O/p load Voltage:

5. Half wave controlled rectifier with
Inductive load

9. Effective value of load with free wheeling diode is:

10. Full Wave Control circuit
• Two SCR’s or a Triac are used for full-wave AC
• Symmetrical triggering is used in each half-cycle.
Two basic configurations for full wave circuits:
1. Mid-point configuration:-require center tap
transformer.
2. Bridge circuit: requires no input transformer.

11. Mid-point configuration
• M-2 connection:-means single phase full wave circuit
with two SCR’s. k/as two pulse converters.
• M-6 connection:- is a three phase full wave circuit with
6 SCR’s. k/as six pulse converters.
Bridge circuit configuration
• B-2 connection: Single phase
• B-6 connection: Three Phase

15. DC output voltage without freewheeling
diode

16. DC o/p voltage with free wheeling
diode

17. DC o/p voltage with free wheeling
diode

18. 3 Phase full wave controlled bridge
rectifier