Lincoln Electric SVM199-A Welder User Manual


 
THEORY OF OPERATION
E-7 E-7
INVERTEC® V450-PRO
INSULATED GATE BIPOLAR
TRANSISTOR (IGBT)
OPERATION
An IGBT is a type of transistor. IGBT are semiconduc-
tors well suited for high frequency switching and high
current applications.
Example A in Figure E.6 shows an IGBT in passive
mode. There is no gate signal, zero volts relative to the
source, and therefore, no current flow. The drain termi-
nal of the IGBT may be connected to a voltage supply;
but since there is no conduction, the circuit will not sup-
ply current to components connected to the source.
The circuit is turned OFF like a light switch.
FIGURE E.6 - IGBT OPERATION
Example B shows the IGBT in an active mode. When
the gate signals a positive DC voltage relative to the
source, is applied to the gate terminal of the IGBT, it is
capable of conducting current. A voltage supply con-
nected to the drain terminal will allow the IGBT to con-
duct and supply current to the circuit components cou-
pled to the source. Current will flow through the con-
ducting IGBT to downstream components as long as
the positive gate signal is present. This is similar to
turning ON a light switch.
DRAIN
SOURCE
GATE
A. PASSIVE
B. ACTIVE
BODY REGION
DRAIN DRIFT REGION
BUFFER LAYER
INJECTING LAYER
DRAIN
SOURCE
G
ATE
B
ODY REGION
DRAIN DRIFT REGION
BUFFER LAYER
INJECTING LAYER
n+n+
P
n
-
n+
P+
n
+n+
P
n-
n+
P+
POSITIVE
V
OLTAGE
A
PPLIED
DRAIN
SOURCE
GATE
A. PASSIVE
B. ACTIVE
BODY REGION
DRAIN DRIFT REGION
BUFFER LAYER
INJECTING LAYER
DRAIN
SOURCE
G
ATE
B
ODY REGION
DRAIN DRIFT REGION
BUFFER LAYER
INJECTING LAYER
n+ n+
P
n
-
n+
P+
n
+ n+
P
n-
n+
P+
POSITIVE
V
OLTAGE
A
PPLIED
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