Theory of operation, Output rectification and control – Lincoln Electric INVERTEC V250-S User Manual
Page 29
E-5
THEORY OF OPERATION
E-5
OUTPUT RECTIFICATION
AND CONTROL
The AC output from the main transformer secondary
is rectified to a DC output and applied to the output
terminals. Output voltage and current feedback infor-
mation, which is fed to the control board, is sensed at
the output terminals and shunt. The control board
monitors the panel controls and remote control recep-
tacle and compares these commands to the feedback
information to determine how the output should be
controlled to optimized welding results. The control
board controls the IGBT switching through pulse width
modulation circuitry. See
IGBT Operation Discussion
in this section.
FIGURE E.4 OUTPUT RECTIFICATION AND CONTROL
INVERTEC V250-S
INPUT
LINE
SWITCH
INPUT
RECTIFIER
R
E
C
O
N
N
E
C
T
S
W
I
T
C
H
AUXILIARY
TRANSFORMER
FAN
MOTORS
POWER BOARD
MAIN
TRANSFORMER
SHUNT
POSITIVE
OUTPUT
TERMINAL
NEGATIVE
OUTPUT
TERMINAL
THERMAL
LIGHT
REMOTE
RECEPTACLE
OUTPUT
CONTROL
STRIKE
CONTROL
ARC
FORCE
CONTROL
MODE
SWITCH
LOCAL/
REMOTE
SWITCH
RELAY
CAPACITOR
CAPACITOR
IGBT
IGBT
IGBT
IGBT
CURRENT
TRANSFORMER
18VAC
GATE SIGNALS
THERMOSTATS
O
V
E
R
V
O
L
T
A
G
E
PROTECTION SIGNAL
CR1 RELAY DRIVE SIGNAL
CR1
IGBT
CONTROL BOARD
A"
L
E
A
D
"
F
E
E
D
B
A
C
K
F
E
E
D
B
A
C
K
NOTE: Unshaded areas of block logic diagrams are the subject of discussion.