Lincoln Electric V205-T service manual Figure E.3 Main Igbt Inverter Board

Page 33

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E-3

E-3

THEORY OF OPERATION

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

ckt.AConturn

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

 

 

 

Remote

48 VDC75, 76, 77 A, B, C

Gas

Solenoid

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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 cir- cuit 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 main- tained 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 cur- rent limiting circuit. The capacitors are charged slow- ly 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 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 pre- vent output until the machine cools and the ther- mostats 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.

V205-T AC/DC

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Contents Invertec V205-T AC/DC Safety Electric Shock can kill Cylinder may explode if damaged Sûreté Pour Soudage a L’Arc Précautions DE SûretéMaster 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 Connection for Stick Output and GAS Connection for TIG Welding Figure A.1Work Cable Connection Shielding GAS Connection Remote Control ConnectionV205-T AC/DC Table of Contents Operation Section General Description Safety InstructionsWelding Capability LimitationsFigure B.1 Rear Control Panel Figure B.1Figure 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.5 Copper TIG Welding Steel TIG WeldingTips for AC TIG Welding Filler MaterialProtective GAS AC TIG Welding Quick Start UPDC TIG Welding Quick Start UP Accessories Table of ContentsCompatible Equipment Optional AccessoriesCable Plugs TIG Torch KitsTable of Contents Maintenance Safety Precautions Input Filter Capacitor Discharge ProcedureRoutine Maintenance Table of Contents Theory of Operation Section Theory of Operation General DescriptionInput Board and BUS Board Figure E.3 Main Igbt Inverter Board Main Igbt Inverter BoardOutput Module Transistor Board Main TransformerOutput Module and Clamping Board Superimposition BoardOutput Filter Board CONTROL/DISPLAY Board High Frequency HF BoardFigure E.6 Igbt Insulated Gate Bipolar Transistor Igbt OperationTable of Contents Troubleshooting & Repair Section HOW to USE Troubleshooting Guide Troubleshooting & RepairElectric Shock can kill PC Board Troubleshooting ProceduresOutput Problems Function Problems Function Problems Secondary Power Board Test Welding Problems Figure F.1 External Diagnostics Troubleshooting & Repair External DiagnosticsFigure F.2 Troubleshooting & Repair Internal DiagnosticsLED Internal DiagnosticsV205-T AC/DC Description Input Filter Capacitor Discharge ProcedureDischarge Procedure Input Filter Capacitor Discharge ProcedureInput Filter Board Test Input Filter Board Figure F.5 Input Filter Board V205-T AC/DC Main Igbt Inverter Board LOW Voltage Test Main Board Table F.1 Test Points LEDFigure F.7 Main Igbt Inverter Board Location TP2 MF2CONTROL/DISPLAY Board Test Control/Display Board Figure F.9 CONTROL/DISPLAY Board Location CN2 CN7 CN1Table F.2 Plug CN1 Test Points CN1Table F.3 Plug CN2 Test Points Table F.4 Plug CN7 Test PointsBUS Board Test BUS Board Table 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 PointsCN4 CN2Main Inverter Board Upfr Section Test Table F.10 Voltage Checks with 115 VAC Applied to Machine Figure F.14 Upfr Location on Main BoardDD1 MF9 TP9 Gndpwr RL1V205-T AC/DC Output Filter Board Test Troubleshooting and RepairOutput Filter Board Figure F.18 Output Filter Board Plug CN1 Figure F.17 Output Filter Board Plug LocationV205-T AC/DC Secondary Power Board Test Secondary Power Board Table F.13 Voltage Checks with 115 VAC Applied to Machine Figure F.20 Secondary Power Board Test Point LocationsV205-T AC/DC Main Inverter Board Welding Logic and Inverter Section Test Figure F.21 Main Board Location Main Inverter BoardTable F.17 LED Check in Stick Mode Table F.15 Feedback Voltage SignalsTable F.14 LED Functions Table F.16 Voltage Checks with 115 VAC Applied to MachineTP14 TP15 TP16 TP19 TP31 CN4/1-2 Short Circuit Ohms CN5/1-2 MF15 VDS MF12 MF16 VDS Figure F.23 Main Board Lower Left TP9 Ground PowerV205-T AC/DC Input Filter Board Removal and Replacement Input Filter Board Removal and Replacement RV1 V205-T AC/DC Main Igbt Board Removal and Replacement Main Igbt Board Removal & Replacement CN2 CN1 V205-T AC/DC CONTROL/DISPLAY Board Removal and Replacement CONTROL/DISPLAY Board Removal & Replacement CN3 CN7V205-T AC/DC Output Filter Board Removal and Replacement Removal and Replacement Casefront Mounting Screws Phillips Head Screws CN1 CN2 Output Diodes Removal and Replacement Figure F.35 Output Diode Location Output DiodesOutput Transistor Removal and Replacement Output Transistor Removal and Replacement Plug CN1 5mm V205-T AC/DC Table of Contents Electrical Diagrams Section Electrical DiagramsWiring Diagram V205-T AC/DC Standard Diagram SVM Error Reporting Form
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