Lincoln Electric SVM161-A service manual Figure E.3 Main Igbt Inverter Board

Page 37

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E-3

THEORY OF OPERATION

E-3

 

FIGURE E.3 - MAIN IGBT INVERTER BOARD

Fan

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Superimposition

 

 

 

 

 

 

 

 

 

 

 

 

board

 

 

 

 

 

 

 

 

 

 

 

24 VDC

Bus board

 

 

 

 

 

 

 

 

 

AC DC Gate drive signals

 

 

 

Input

 

 

 

 

 

 

 

 

 

HF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

board

 

 

 

 

 

board

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Voltage Feedback

 

 

 

 

 

15,+5-+24,+15,48,-

info.reconnect

.ACcktturnon

supplyvolthigh

feedbackvoltage

feedbackcurrent

 

 

 

 

Current Feedback

 

 

 

 

 

 

 

 

 

Output

 

 

 

 

 

 

 

 

 

 

 

 

IGBT

 

Diode

 

 

 

 

 

 

 

 

 

 

 

 

 

Thermostat

 

 

 

Output

 

 

 

 

 

 

 

Thermostats

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Filter bd.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(bypass)

 

Main IGBT

 

 

 

 

 

 

 

 

 

 

 

 

 

& Power board

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

_

 

 

 

 

 

 

 

 

IGBT's

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Output

RF coil

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Choke

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

infothermostat

metervoltinput

metercurrentinput

 

DC blocking

 

 

Current

 

 

 

 

 

ckt.AConturn

+515,-+15,

infoset

PWMonturn

capacitor board

 

 

 

 

 

Input

 

 

 

Hall

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Main

 

Output

 

 

 

Choke

 

 

 

 

 

 

 

Output

Device

 

 

 

 

 

 

 

 

 

 

 

 

Transformer

board

Transistor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Module

 

 

 

 

 

 

 

 

 

 

 

 

 

24 VDC Remote 2/4 path (D + E)

 

 

 

 

HF control signal

 

 

 

 

 

 

 

888

 

 

 

 

+48, +24

 

 

 

 

 

Control board

Display & LED

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

board

 

 

 

 

Control

(D + E)

Remote 2/4

Knob

 

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48 VDC

Gas

Solenoid

MAIN IGBT INVERTER BOARD

The filtered input voltage, from the Input Board, is applied through an input choke to the Main IGBT Inverter Board. This input voltage is rectified, regulat- ed and a unity power factor output is developed for the main welding IGBTs. This unity power factor circuit provides several advantages over a traditional bridge rectifier circuit. Among these advantages are that the UPFR operates over a wide range of voltages, there is no need for any manual circuit changes when the input voltages are changed from 115VAC to 230VAC and there is absolute voltage stability maintained on the IGBT electrolytic capacitors. The four main welding IGBTs are located on a large center mounted heat sink assembly.

The pre-charge and auto reconnect circuits are posi- tioned on the Main IGBT Inverter Board. When power is first applied to the V205T the rectified DC input volt- age is applied to the input capacitors through a current limiting circuit. The capacitors are charged slowly and current limited for approximately five seconds. After five seconds a relay closes and the pre-charge circuit is bypassed and a controlled DC input voltage is applied to the weld capacitors and IGBTs making them ready for welding output demands when the IGBTs are gated on. The auto reconnect circuit receives and processes a low-level voltage signal from the Bus Board. This low level signal is utilized to adjust for the

Remote 75, 76, 77 A, B, C

different voltage requirements needed by the weld IGBT circuits. A signal is also sent to the Control Board so that when the input voltage is reduced the output of the machine will be limited accordingly.

The Auxiliary power portion of the board generates several voltages through flyback topology and a 50KHZ switching frequency. These various voltages (+24, +15, +5, +48 and –15) are utilized to operate the control and protection electronics, the gas solenoid, the trigger circuit and the fan motor.

The Main IGBT Inverter Board receives command and pre-set signals from the Control/Display board. It also receives feedback information, both voltage and cur- rent, from the Output Filter Board and Hall Effect Device via the Bus Board. It processes this informa- tion and generates the correct pulse width modulation signal (PWM) that is applied to the gates of the weld IGBTs. This controls and regulates the output of the machine. The thermostats signals are connected to the Main IGBT Inverter Board. This status information is passed on to the Control Board. In the case of an over temperature condition the Control Board will prevent output until the machine cools and the thermostats reset.

Low-level analog signals are generated on the Main IGBT Inverter Board and sent to the Control/Display Board for meter set and actual display values.

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NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion

INVERTEC® V205-T AC/DC™

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Contents Invertec V205-T AC/DC Invertec V205-T AC/DC SafetyCan be dangerous Electric Shock can kill ARC Rays can burnWelding Cutting Powered equipmentCylinder may explode Sparks can cause fire or If damaged ExplosionSûreté Pour Soudage a L’Arc Précautions DE SûretéSafety Methods of Reducing Emissions Mains Supply Master Table of Contents for ALL Sections Table of Contents Installation Section Operating Temperature Range Storage Temperature Range InstallationStacking Select Suitable LocationTilting Environmental AreaInput Connections Reconnect Procedure230V Input Attachment Plug Installation115V Input Engine Driven GeneratorOutput and GAS Connection for TIG Welding Figure A.1 Output ConnectionsWork Cable Connection Shielding GAS Connection Remote Control ConnectionInvertec V205-T AC/DC Table of Contents Operation Section Operation Safety InstructionsGeneral Description Welding CapabilityRear Control Panel Figure B.1 OPERATIONB-3Figure B.2 Controls and SettingsLocal/Remote push button Selects the welding Step DiagramTIG DC TIG AC Indicator Parameter Default SET UP MenuWelding Polarity Output LimitationsFigure B.7 Copper TIG Welding Steel TIG WeldingTips for AC TIG Welding Filler MaterialProtective GAS AC TIG Welding Quick Start UPDC TIG Welding Quick Start UP Table of Contents Accessories Section Optional Accessories AccessoriesCompatible Equipment Cable PlugsTable of Contents Maintenance Section Safety Precautions MaintenanceInput Filter Capacitor Discharge Procedure Routine MaintenanceFigure D.1 Major Component Locations 3MAINTENANCEInvertec V205-T AC/DC 1TABLE of CONTENTS-THEORY of Operation Section E-1 Input Board and BUS Board Theory of OperationFigure E.3 Main Igbt Inverter Board Main Igbt Inverter BoardOutput Module Transistor Board Main TransformerOutput Module and Clamping Board Superimposition BoardHigh Frequency HF Board CONTROL/DISPLAY BoardOutput Filter Board Passive Active Insulated Gate Bipolar Transistor Igbt Operation1TABLE of Contents Troubleshooting and Repair F-1 HOW to USE Troubleshooting Guide Troubleshooting and RepairElectric Shock can kill PC Board Troubleshooting ProceduresIgbt Perform the Input Filter Board Igbt Inverter Board Test Secondary Output Board Assembly Test See the Output Filter Display Troubleshooting and Repair External DiagnosticsFigure F.2 Troubleshooting and Repair Internal DiagnosticsLED Internal DiagnosticsInvertec V205-T AC/DC Materials Needed Test DescriptionCapacitor Solder Resistor Pads Input Filter Capacitor Discharge ProcedureInput Filter Board Test Input Filter Board Test ProcedureInput Filter Board Input Filter Board Invertec V205-T AC/DC Main Igbt Inverter Board LOW Voltage Test Figure F.6 Main Igbt Inverter Board Location Main Igbt Inverter Board LOW Voltage TestLED Main Igbt Inverter Board LOW Voltage TestFigure F.7 Main Igbt Inverter Board Location TP2 MF2CONTROL/DISPLAY Board Test Figure F.8 CONTROL/DISPLAY Board Location CONTROL/DISPLAY Board TestFigure F.9 CONTROL/DISPLAY Board Location CN2Figure F.10 Plugs CN1, CN2 & CN7 CN1BUS Board Test Figure F.11 BUS Board Location BUS Board TestTable F.6 Plug CN3 Test Points Table F.5 Plug CN2 Test PointsTable F.7 Plug CN4 Test Points Table F.8 Plug CN7 Test PointsCN1 CN2 Main Inverter Board Power Factor Section Test Table F.10 Voltage Checks with 115 VAC Applied to Machine Main Inverter Board Power Factor Section TestTable F.11 Resistance Checks TP9 Gndpwr RL1 Invertec V205-T AC/DC Output Filter Board Test Figure F.16 Output Filter Board Location Output Filter Board TestFigure F.18 Output Filter Board Plug CN1 Figure F.17 Output Filter Board Plug LocationInvertec V205-T AC/DC Secondary Output Board Assembly Test Figure F.19 Secondary Power Board Location Secondary Output Board Assembly TestOFF GA-SA Table F.14 Output Diode Resistance Check Mode Positive Meter Negative Meter Expected Reading ProbeMain Inverter Board Welding Logic and Inverter Section Test Welding Logic and Inverter Section Test Main Inverter BoardTable F.18 LED Check in Stick Mode Table F.16 Feedback Voltage SignalsTable F.15 LED Function Table F.17 Voltage Checks with 115 VAC Applied to MachineFigure F.22 Main Board Inverter Section TP9 Ground Power Invertec V205-T AC/DC Input Filter Board Removal and Replacement Figure F.24 Input Filter Board Location Input Filter Board Removal and ReplacementRV1 RV2 Invertec V205-T AC/DC Main Igbt Board Removal and Replacement Figure F.27 Main Igbt Board Location Main Igbt Board Removal and ReplacementRV1 RV2 CN4 RV3 RV4 CN5 RV5 RV7 RV6 Invertec V205-T AC/DC CONTROL/DISPLAY Board Removal and Replacement Figure F.29 CONTROL/DISPLAY Board Location CONTROL/DISPLAY Board Removal and ReplacementCN2 Invertec V205-T AC/DC Output Filter Board Removal and Replacement Figure F.32 Output Filter Board Location Removal and ReplacementPhillips Head Screws CN1 Output Diodes Removal and Replacement To Replace ANY of the Output Diodes D1, D2, D3 or D4 Output Diodes Removal and ReplacementOutput Transistor Removal and Replacement Figure F.36 Output Transistor Location Output Transistor Removal and ReplacementPlug CN1 5mm Allen Bolts Invertec V205-T AC/DC Table of Contents Diagram Section ELECTriCaL DiaGramS
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