A001 Control Card - Kemppi MinarcTig Evo 200 Service Manual

Service manual MinarcTig Evo 200
diode and PFC choke) keeps the primary currents and voltage in the same phase.
This rises the power factor up to 0,98. PFC is boost type and raises the DC-link volt-
age up to 390VDC.

Power section is based on dual forward architecture with 60 kHz switching frequency.
IGBTs have two stages: ON/conducting and OFF/demagnetizing. OFF-stage must
last longer comparing to ON-stage because main transformer needs to be demagnet-
ized or otherwise it goes to saturation.

IGBT module has integrated NTC resistor for over heat protection: In 0-40° C envi-
ronment temperature range resistance varies between 14-2,8kΩ if the machine is
cool (values are not exact because some components affect the measured value). In
the overheat situation NTC resistance reduces and machine stops the inverter at the
500Ω point. Note that NTC has descending nominal curve: When temperature rises
resistance lowers.

Z001 card has auxiliary power supply that delivers auxiliary voltages to Z001 card.
There are two secondary voltages: +16VDC for the IGBT gate driver circuits and
+24VDC for the cooling fan and charging relay.

DC-link with three 470μF electrolytic capacitors. Machine current is measured in the
DC-link and feedback goes to the A001 card.

Secondary rectifier has two working and four demagnetizing diode packages. Each
package holds two diodes so total quantity is double.

Cooling fan control circuit. Control signal comes from the P001 card. Note that cool-
ing fan uses +24VDC that is in the primary side.

Dual forward inverter gate driver circuit. Control signal is coming from the A001 card.

Spark protection against HF ignition sparks

3.4.2. A001 Control card


MMA dynamics function. Adjustment is made in panel setup.

A001 card has auxiliary power supply; it rectifies the auxiliary transformers secondary
voltage 20VAC to 28VDC. Switching circuit regulates it to +24VDC, and produces un-
regulated +8VDC, from which a +5VDC regulated supply is generated.

PWM circuit for controlling the inverter. Secondary current is measured in the shunt
and feedback is used to make correct adjustments. PWM circuit adjusts also open
circuit voltage and its level can be selected from panel software (+95VDC or 30VDC
VRD).

Secondary voltage measuring. Value is delivered to P001 card.

Connection to P001 card.

Gas valve control circuit. P001 microprocessor gives control signal to A001 card.

Control to DC-link soft start charging relay and over voltage watch.

PFC control circuit. Control signal comes from the microprocessor on the P001 card.

Under voltage watch. It shuts down the inverter and information is delivered to micro-
processor on the P001 card.
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Kemppi Oy
Version 1.1.5. 29.9.2015