This document discusses three-phase converters that convert AC power to DC power for loads. It specifically describes three-phase half-wave controlled rectifiers, which are made up of three single-phase half-wave converters connected together. It provides the equation to calculate the average DC output voltage of a three-phase half-wave converter and discusses that the thyristor conducts from 30 degrees to 180 degrees for a resistive load. The document concludes by describing a problem to calculate firing angle, average/RMS load current, and efficiency for a 3-phase converter operating from a 230V 50Hz supply with a 10 ohm resistive load and 50% of maximum output voltage required.

1.  TEAM MEMBERS:
 S.MADHURA LAKSHMI-14F29
 RAGHU RAMAN
 PRIYADHARSHAN

2.  Three phase converters are 3-phase controlled rectifiers
which are used to convert ac input power supply into dc
output
power across the load.
 Features of 3-phase controlled rectifiers:
 Operate from 3 phase ac supply voltage.
 They provide higher dc output voltage and higher dc
output power.
 Higher output voltage ripple frequency
 Three phase controlled rectifiers are extensively used in
high power variable speed industrial dc drives.

3.  Three single phase half-wave converters are connected
together to form a three phase half-wave converter as
shown in the figure.

4.  R LOAD

5.  In the case of a three-phase half wave controlled rectifier with
resistive load, the thyristor T1 is triggered at wt=30degree+alpha
and T1 conducts up to wt= 180degree=3.14 radians.
 When the phase supply voltage an v decreases to zero at wt=3.14
the load current falls to zero and the thyristor T1 turns off. Thus
T1 conducts from wt=30degree to 180degree
 Hence the average dc output voltage for a 3-pulse converter (3-
phase half wave controlled rectifier) is calculated by using the
equation

7.  A 3-phase M-3 conuerter is operated from 3-
phase, 230 Vi 50 Hz supply with load
resistance R = 10 n. An auerage output
uoltage of 50% of the maximum pos§.ible
output uoltage is required. Determine (a)
the firing angle (b) auerage and rms "Glues
of load current and (c) rectification
efficiency.

10. Thank You For Your Co-operation.