Phase-Controlled Converters

PHASE-CONTROLLED CONVERTERS

1. Introduction

`Rectifier are used to convert A.C to D.C supply.

`Rectifiers can be classified as single phase rectifier and three phase rectifier. Single phase rectifier are classified as 1-Փ half wave and 1-Փ full wave rectifier. Three phase rectifier are classified as 3-Փ half wave rectifier and 3-Փ full wave rectifier. 1-Փ Full wave rectifier are classified as1-Փmid point type and 1-Փ bridge type rectifier. 1-Փ bridge type rectifier are classified as 1-Փ half controlled and 1-Փ full controlled rectifier. 3-Փ full wave rectifier are again classified as 3-Փmid point type and 3-Փ bridge type rectifier. 3-Փ bridge type rectifier are again divided as 3-Փ half controlled rectifier and 3-Փ full controlled rectifier.

2. Single phase half wave circuit with R-L load

Output current io  rises gradually. After some time io  reaches a maximum value and then begins to decrease.

At π, vo =0 but io is not zero because of the load inductance L. After π interval SCR is reverse biased but load current is not less then the holding current.

At β>π, io reduces to zero and SCR is turned off.

At 2π+β SCR triggers again 

α is the firing angle

3. Single phase full converter

4. Single phase half wave circuit with RLE load

5. Single phase full wave converter:

6. Single phase semi converter: