Reliability Issues of
IGBT based Converters
March’2017
1
2
Period Total Failure per 100 loco
SR BUR SR BUR
2015-16 19 9 5.3 2.5
2016-17 29 17 4.6 2.7
IGBT Converter Failure Comparison
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Period Total Failure per 100 loco
SR BUR SR BUR
2015-16 47 29 6.7 5.6
2016-17 37 15 5.2 2.1
GTO Converter Failure Comparison
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Period Total Failure per 100 loco
VCU Transient VCU Transient
2015-16 51 61 4.8 5.8
2016-17 35 50 2.6 3.8
Central Electronics - Failure Comparison
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Period Total Failure per 100 loco
2015-16 465 44
2016-17 456 34
Total Failure Comparison of 3-ph loco
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Performance of M/s. ABB make Converters (IGBT)
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SN Cause of Failure No. of Failures
2015-16 16-17 (Feb’17)
1 Duagon Card defective 10 4
2
Software Malfunctioning (Time out
initialization, harmonic filter current
high, etc) 44 36
3 PEC (controller card) defective 11 11
4 Gate Driver Unit (GDU) cards 14 10
5 Pump Failure / Fan Failure 2 6
6 Loose connector/OFC/ Cable
defective 6 4
7 PEBB (Power Module) Failure 12 18
8 Others (transient, contactor stuck
up, MCB trip etc) 52 32
9 TOTAL 151 121
10 Total Population 115 156
11 FRPCPY 131 85
Performance of M/s. ABB make Traction Converter
Major issues
• Software issues
• Failure of Duagon card
• Failure of PEBB modules
• Failure of PEC card
Performance of M/s. ABB make Traction Converter
Software issues already addressed:
• Time-out initialization,
• Wrong logic of coolant level,
• Mapping of display of DDS message,
• Harmonic filter contactor stuck ON/OFF etc.
The software version 37 (416T37AB) has been put in regular use.
Performance of M/s. ABB make Traction Converter
Software issues
Pending Software issues
• Harmonic Filter Over current.
• Time out release shut down due to non availability of timely signal from converter to VCU (within 150 ms) for DC link voltage discharge.
• The final iteration of the software version 38 addressing all the pending issues has been downloaded in 6 locos in Sept’2016.
ELS/GZB - 2 locos
ELS/TKS - 3 locos
ELS/AQ - 1 loco
• Performance is under watch for its regular use.
Performance of M/s. ABB make Traction Converter Software issues
Root cause: Firmware malfunctioning. The
modified firmware downloaded in all locos.
Firm has recently provided modified Duagon card
(D709) with optical connection in place of
hardwired electrical connection provided in
existing duagon card (D429).
Last 10 months - no failure of firmware of Duagon
card.
This problem has been addressed.
Performance of M/s. ABB make Traction Converter
Failure of Duagon card
Firm has mentioned the reason of failures as: • Particle impurity in the IGBT conduction area
• Thermal paste missing from the screw holes
Defective lot of IGBTs (23 locos) identified and replaced.
Failure still persisting.
(12 cases in 2015-16 to 18 cases in 2016-17.)
Reports of recent failures are still awaited.
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Performance of M/s. ABB make Traction Converter
Failure of PEBB Modules
Problem identified as flash memory corruption and use of wrong PEC tool.
Firm has upgraded the DOS file management system to reliance file management system to address failures of flash memory corruption.
Proper PEC tool (latest version PEC 3.0) to be used for downloading by sheds.
O/p voltage communication problem due to short circuit addressed by removal of ‘0’ voltage level.
Performance under watch.
Performance of M/s. ABB make Traction Converter
Failure of PEC Card
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SN Cause of Failure
No. of Failures
2015-16 2016-17
(Feb’17)
1 IGBT burst (inverter module) 2 3
2 Converter module 0 1
3 PCB cards 5 6
4 Battery charger module 0 1
5 Software malfunctioning 4 12
6 Misc. 6 10
7 TOTAL 24 33
8 Total Population 21 29
9 FRPCPY 114 124
Performance of M/s. ABB make Aux. Converter
Major issues
• Software issues
• Failure of PCB cards
• IGBT burst
Performance of M/s. ABB make Aux. Converter
Software issues - Resolved
Performance of M/s. ABB make Aux. Converter
• FLG Redundancy
• FLG Redundancy is now made available for auxiliary
converters.
• DDS Mapping issues
• DDS For traction and aux converters is available, will be cut
into the fleet by June-2017
• MVB Failure
• The time life sign monitoring of the FLG has been relaxed to
avoid spurious faults
Software issues - Pending
Performance of M/s. ABB make Aux. Converter
• Ventilation Adaptation
• Updation rate optimized to improve the ventilation
feedback from BUR to the VCU/Traction Converter.
• However problem still in one loco of RPM (30479). Firm
shall use data logger to capture the data to find the real
cause.
Failure of PCB cards
• Main Controller card (1 case) due to
power supply short at terminal.
• Gate Drive Unit (5 cases) – Failures are
under investigation by firm.
Performance of M/s. ABB make Aux. Converter
IGBT failures
• Earth fault detection system was causing
flow of circulating current through IGBT.
• The earth fault detection from the
output side has been removed in 1 loco
no 30095 in ELS/BRC (Jan’17).
• Performance under watch.
Performance of M/s. ABB make Aux. Converter
20
Performance of M/s. BHEL make Converters (IGBT)
21
SN. Cause of Failure
No. of Failures
2015-16 2016-17
(Feb’17)
1 Power Module/PMI/USID 57 90
2 VIU/DCU Card 17 26
3 Coolant Pump 1 11
4
Software Malfunctioning
(Harmonic filter stuck, ASC
pulsing stopped, TFP oil
pressure not OK, etc)
10 14
5 Pressure Switch 42 15
6 Misc. (Transient /random faults) 16 26
7 Total Failures 143 182
8 Total Population (loco) 140 176
9 FRPCPY 112 112
Performance of M/s. BHEL make Traction Converter
1. Software malfunctioning
2. Failure of VIU/DCU card
3. Failure of Power Module
4. Pressure switch failure
5. Coolant leakage/fluctuation
Performance of M/s. BHEL make Traction Converter
Major issues
Software version 371 (416T371BH) approved for regular cut-in after extensive field trial in June’2016.
It has addressed followings :
(i) ASC pulsing stop message;
(ii) Transformer oil pressure not OK;
(iii) Protective turn-off time out;
(iv) Fine tuning of DC link to eliminate locking of traction converter electronics.
Performance of M/s. BHEL make Traction Converter
Software malfunctioning
Problem still persists
(i) Harmonic contactor stuck ON/OFF, time delay increase from 1 sec. to 1.2 seconds;
(ii) Earth fault protection: TC to be isolated if problem occur 2-3 times.
Software is uploaded in 1 loco each of ELS/BIA & ELS/LGD (Feb’17).
Performance is under watch.
Performance of M/s. BHEL make Traction Converter
Software malfunctioning
• Precaution should be taken for uploading the software with laptop dedicated for this purpose to avoid software corruption.
• Track burnt/resistor burnt found – Poor manufacturing. BHEL advised.
• Current transformer changed from ABB to LEM make to address this problem.
Performance of M/s. BHEL make Traction Converter
Failure of VIU/DCU cards
• Filter circuit introduced in PMI to address Usid_low error. Still problem not completely resolved.
• Light intensity measurement in optic fibre cable connection being done 100%.
• Approval given for regular use of Mitsubishi make IGBTs.
• In spite of above action plan, no improvement in the failures of Power Modules.
Performance of M/s. BHEL make Traction Converter
Failure of Power Module/PMI
• Problem with Layher make pressure sensor.
• Honeywell make pressure switch has also been used in 10 locos on trial basis.
• Performance of both makes under watch.
• M/s BHEL to use Honeywell make pressure switch.
Performance of M/s. BHEL make Traction Converter
Failure of Pressure switch
• Leakage observed in cooling circuit with threaded joints.
Modified flange coupling
• Performance found satisfactory.
• Being implemented on all new locos.
Performance of M/s. BHEL make Traction Converter
Coolant leakage/fluctuation
• Overflow of coolant and air trap in pipe line
• Additional connection in between conservator and pipe line provided to solve these problems.
• Performance of revised arrangement found satisfactory.
• BHEL has been advised to use this arrangement on regular basis.
Performance of M/s. BHEL make Traction Converter
Coolant leakage/fluctuation
Existing arrangement Modified arrangement
Performance of M/s. BHEL make Traction Converter
Coolant leakage/fluctuation
Failures - - BHEL make Auxiliary Converter
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SN Cause of Failure
No. of Failures
2015-16
2016-17
(Feb’17)
1 Inverter module 21 35
2 Controlled rectifier module 9 7
3 ACI card 11 17
4 AMC card 0 8
5 MVB Fibre interface (MFI card) 3 4
6 Battery Charger 12 11
7 Software malfunctioning 7 7
8 Misc 9 11
Total Failures 94 100
Total Population (loco) 93 180
FRPCPY 102 61
1. Inverter Module
2. Controlled Rectifier Module
3. ACI card
4. AMC card
5. Battery charger
6. Software malfunctioning
Performance of M/s. BHEL make Aux. Converter
Major issues
Performance of M/s. BHEL make Aux. Converter
Inverter Module
• Di/dt error:
―No conclusive report submitted by BHEL
• Miscellaneous:
Random failure – 9, No defect – 5
• Mostly failures are due to components of PCBs like
PCB mounted contactors – K1, K2, K3, K4 etc.
Resistors and capacitors.
• BHEL advised to look into these to improve
reliability.
Performance of M/s. BHEL make Aux. Converter
Controlled Rectifier Module
• Discrete components failure of PCB:
― Failure of components on Gate Driver
― No conclusive report submitted by BHEL
Performance of M/s. BHEL make Aux. Converter
ACI card
• No defect found – 9 cases
• Software corruption – 5 cases
• Track Burnt/resistor burnt – 3 cases
― Failed component are relays, K4-Aux contactor, K1-
contactor due to over voltage/current.
― Resistor/track burnt.
Performance of M/s. BHEL make Aux. Converter
AMC card
• This is a controller card to Gate drive unit.
• Failures are attributed to inadequate biasing
for power supply regulator
• Resistance value changed in the card to
ensure powering even at low voltage.
• Problem mainly due to Measurement Sensors (LEM
make) in imported modules.
• Out of 45 such sensors, 35 have been replaced by
firm.
• In indigenous module, high rating LEM sensors are
being used.
Performance of M/s. BHEL make Aux. Converter
Battery charger
• Problem of software locking of modules.
• No message against BA voltage less than 92 V.
• BA voltage charger message “BA not charging” should be generated by both BUR2 and BUR3.
• Software has been upgraded to version 187.2.
• Performance under watch.
Performance of M/s. BHEL make Aux. Converter
Software Malfunctioning
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Performance of M/s. CGL make Converters (IGBT)
SN Cause of failure 2016-17 (Feb’2017)
1 Power module 6
2 PCB cards 2 3 Coolant pump 1 4 Software malfunctioning 25 5 Others 6
Total 40 Total Population (Loco) 18 FRPCPY 241
Performance of M/s. CGL make Traction Converter
1. Software malfunctioning
2. Power Module failure
3. PCB cards
Performance of M/s. CGL make Traction Converter
Major issues
Following problem addressed:
• Filter current > max. – IGBT firing strategy improved to reduce harmonics.
• Spurious message of TM isolation – Software modified.
• Harmonic filter isolation – Filter adaptation timings have been modified.
Performance of M/s. CGL make Traction Converter
Software malfunctioning
Following problem addressed
• Spurious DC link earth fault message of DC link
positive and negative side – Software filter used to eliminate the problem of spurious generation of
signals.
• TFP pressure > limit – Logic changed.
Performance of M/s. CGL make Traction Converter
Software malfunctioning
Following problem still unresolved:
• Ventilation level mismatch in alt. ‘C’
converters.
Software shall be modified as has been done for
converters supplied as per CLW specification of Alt-D
by 15.04.17
[ELS/TATA – 3, GMO – 7, LDH – 4]
Performance of M/s. CGL make Traction Converter
Software malfunctioning
Following problem still unresolved:
• BUR current increase (> limit of 400 Amp)
This problem is observed during low OHE voltage with
consequent increase in input current of auxiliary converter
which leads to main power OFF.
• Time delay will be introduced to 200 ms (presently
instantaneous) to observe the triggering of
protection action. This may eliminate this problem.
Performance of M/s. CGL make Traction Converter
Software malfunctioning
Performance of M/s. CGL make Traction Converter
Power Module Failure
• In 4 cases, the temperature sensor (SCI/Spain
make) found defective due to problem in welding
process between sensor & cable.
• Firm shall replace sensors by Floricon make within 2
months time (31.05.17) in all the traction
converters.
• 2 cases of IGBT burst. Burst IGBT sent to OEM
(Hitachi) for investigation.
Performance of M/s. CGL make Traction Converter
PCB cards failure
• There are 2 cases of PCB cards failure.
• Failed PCB cards were sent to their principals M/s
CAF/Spain.
• This was investigated in detail and software bugs
were detected. There was no other component
failure.
• Modified software uploaded in all PCB cards.
SN Cause of failure 2015-16
2016-17 (Feb’2017)
1 Power supply card (KUC153 A02)
74 100
2 BUR processor card (CCPU card) 9 33 3 INVCC-01 electronic card 21 51 4 Inverter module 0 1 5 Others 0 15
Total 104 201 Total Population (Loco) 182 217 FRPCPY 57 101
Performance of M/s. CGL make Aux. Converter
1. Failure of PS card (KUC153A02)
2. Failure of BUR processor card (CCPU)
3. Failure of Inverter Control Card (INVCC)
Performance of M/s. CGL make Aux. Converter
Major issues
• Failure was due to large variation in the -24 V supply
• The firm has resolved the issue by regulating the -
24 V supply in the power supply card. The modified
card to be supplied for the field trial in 16 locos.
• Alternatively VCU card (KUB921) Modified and
provided in 80 locos. Performance satisfactory so far
(6 months).
• Performance of KUB921 card is better and therefore
decided that this modification will be implemented
in balance 135 locomotives.
Performance of M/s. CGL make Aux. Converter
Failure of PS card (KUC153A02)
• Switching over from one BUR to another BUR not taking place in case of failure.
• Over sensitively of input channel.
• Sensitivity from 10 V being increased to 36 V by firm.
• Modified cards have been provided in 23 locos for field
trial (TKD – 7, AQ – 2, BRC – 4, GZB – 2, KYN – 2, LGD –
4, VSKP – 2).
• Performance under watch.
Performance of M/s. CGL make Aux. Converter
Failure of BUR processor card (CCPU)
• Spurious inverter fault message in INVCC card.
• To resolve this problem the resistance to sense the
over current has been increased in gate driver and
corresponding software modification in INVCC
card.
• Firm is replacing the cards with modified software
and replacement of resistance in driver card.
• Modified cards have been provided in 23 locos for
field trial (TKD – 7, AQ – 2, BRC – 4, GZB – 2, KYN –
2, LGD – 4, VSKP – 2).
Performance of M/s. CGL make Aux. Converter
Failure of INVCC card
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Performance of M/s. BTIL make Converters (IGBT)
SN Cause of Failure No. of failures 16-17 (Feb’17)
1 Power Module 25
2 Software Malfunctioning 28
4 GDU/DCU card 7
5 Cooling blower 10
6 Others 8
Total Failures 78
Total Population 108
FRPCPY 78
Performance of M/s. BTIL make Traction Converter
• Failure of Power modules
• Software problem
• Cooling blower motor failures
• GDU/DCU card failures
Performance of M/s. BTIL make Traction Converter
Major issues
• Failure noticed in locos turned out from July’2016 to Oct’2016 (mostly line side).
• Investigation report inconclusive due to heavy damage of IGBT.
• Suspected manufacturing defects.
• After replacement, no repeat failure.
Performance of M/s. BTIL make Traction Converter
Failures of Power Modules
• Presently 2 IGBT parallel combination (4.5 KV, 1100 Amp. Rating)
• To avoid mismatch in paralleling, single IGBT of higher rating (4.5 KV, 1500 Amp, Hitachi make).
• 41 locos are in service with 1500 Amp rating IGBT.
• Performance under watch.
Performance of M/s. BTIL make Traction Converter
Failures of Power Modules
• Protective action not allowing DJ to reclose if OHE voltage >29 kV (Particularly after crossing NS) .
―Limit proposed to increase to 30 kV.
• Issue of limitation of the TE in case module of other converter isolated.
―Interlocking signal modified.
• Modified software will be uploaded in locos (ELS/BRC & VSKP) before adopting it on regular basis.
• Time out DC link circuit charge B1 & B2 message leads to bogie isolation and main power off.
• Data being captured in loco of ELS/BRC & ELS/GMO to find the root cause.
Performance of M/s. BTIL make Traction Converter
Software problems
• Imported (Nicotra, German make) fotor failrue due to stator winding failures.
• M/s BTIL proposed to use other make Zielhabegg make.
• Proposed to put on trial basis to watch its performance.
Performance of M/s. BTIL make Traction Converter
Cooling blower failures
• Gate Driver Unit (GDU) failed mostly at the time of power module failures.
• DCU card failures attributed to bad workmanship while crimping fibre optic cables of the card.
• Reason of failures identified for needful action.
Performance of M/s. BTIL make Traction Converter
Card failures
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Performance of M/s. Medha make Propulsion system
SN Cause of Failure No. of failures
2015-16 16-17
(Feb’17)
1 Card failure 0 4
2 VCU problem 1 1
3 Software Malfunctioning (Time out
initialization, Time mis-match etc) 1 1
4 Converter contactor 2 2
5 Power Module 3 0
6 TM speed sensors 0 5
7 Loose connector / OFC/ Cable
defective 0 1
8 Others / Misc. 5 2
Total 12 16
Population 9 22
FRPCPY 150 79
Performance of M/s. Medha make Propulsion
• Speed Sensors failure
• PCB card
• VCU problem
• Converter contactor
Performance of M/s. Medha make Propulsion system
Major issues
Tooth wheel of other make installed which resulted in
missing pulsed at speed>100 KMPH
Performance of M/s. Medha make Propulsion system
1. Speed Sensors failure
2. VCU Problem
Input card pin not connected properly and bent causing
short circuit.
3. Converter contactor
Pick up voltage adjusted. No problem at present.
• Grounding issue in TCN card (MU) – 2 nos.
• Voltage sensor card failed due to defect in LEM sensor
– 1 no.
• Battery charger controlled card changed on precaution.
Nothing found in Lab – 1 no.
Performance of M/s. Medha make Propulsion system
4. PCB card
Thanks !
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