Kemppi WELDFORCE KPS 3500, Руководство по обслуживанию, Страница: 4 / 18

Operation principle
KEMPPI
WELDFORCE
TM
-power sources are versatile, MIG/MAG- and MMA-suitable inverters .
KEMPPI
WELDFORCE
TM
-power sources are based on IGBT technology and controlled by PWM
principle. The inverter frequency changes by the load, in range of 14 - 24 kHz.
KEMPPI
WELDFORCE
TM
-power sources are microprocessor controlled, so all welding
characteristics are programmatically generated.
KEMPPI WELDFORCE
TM
-power source´s operation principle is shown below:
appr. + 570 V
C2
C3
V2
V3
T1
KEMPPI
WELDFORCE
TM
-power source´s
power stage is a traditional half bridge,
where the intermediate circuit DC-voltage is
halved by working capacitors C2 and C3.
IGBT-transistors work as power switches.
When both IGBTs are non-conductive, no
power is transferred.
When the upper IGBT V2 is conductive, the
main transformer T1´s primary side has
positive voltage. When the lower IGBT is
conductive, there is negative voltage.
Power is adjusted by altering the IGBT-
transistors conductive timings (PWM).
The main transformer T1´s secondary
voltages are rectified by a full-wave
rectifier.
Voltage over the lower IGBT with minimum values.
(MIG 10A/14,5V)
100V, 20µs/DIV
U
V3
Voltage over the lower IGBT with maximum values
(MIG 450A/36,5V)
100V, 20µs/DIV
4