Kemppi miniarc 140 - Operating Principle and Main Circuit; Operating Principle Explanation; Main Circuit Diagram Overview

Operating principal
VDC
t
105
13µs
Max. 0,5
n. + 320 V
1/3
V1
V2
When IGBT-transistors V1 and V2 are not conductive, no power is transferred. The power is
adjusted by changing the IGBT-transistors conductive timings (PWM).
Main circuit
+ t + t
X3
X1
X2
R69R70
L2
C28
C22C5
L1
R59 R54
C43
V26 V23
V9
C1, C2, C3
V5, V32
V1, V31
V2, V3, V4V6, V7, V8
T001T2
K1
T001
U
R64
U
V29, V 30
C39
R65
R66
C38
V27, V28
R63
X18
X17
L001
L002
X003
X004
X16
X3
X2
Z001
Minarc power sources are ”dual-Forward”-inverter power sources, controlled by PWM method.
The switching components are IGBT-transistors. Inverter operating frequency is approx. 80 kHz.
Below is a picture of the ”dual-forward”-inverter operating principal:
4