Reliability Issues of IGBT based Converters - Indian...

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

3


SR BUR SR BUR

2015-16 47 29 6.7 5.6

2016-17 37 15 5.2 2.1

GTO Converter Failure Comparison

4


VCU Transient VCU Transient

2015-16 51 61 4.8 5.8

2016-17 35 50 2.6 3.8

Central Electronics - Failure Comparison

5


2015-16 465 44

2016-17 456 34

Total Failure Comparison of 3-ph loco

6

Performance of M/s. ABB make Converters (IGBT)

7

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


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.


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.


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.

12


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.


Failure of PEC Card

14

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


Software issues - Resolved


• 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


• 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.


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.


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


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.


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.



• 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.


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.


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.


Failure of Pressure switch

• Leakage observed in cooling circuit with threaded joints.

Modified flange coupling

• Performance found satisfactory.

• Being implemented on all new locos.


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.



Existing arrangement Modified arrangement



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


Performance of M/s. BHEL make Aux. Converter

Major issues


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.


Controlled Rectifier Module

• Discrete components failure of PCB:

― Failure of components on Gate Driver

― No conclusive report submitted by BHEL


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.


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.


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.



Software Malfunctioning

39

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


2. Power Module failure

3. PCB cards


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.



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.



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]



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.




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.


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)


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.


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).



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).


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


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.


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.



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.


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.


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.


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


Major issues

Tooth wheel of other make installed which resulted in

missing pulsed at speed>100 KMPH


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.


4. PCB card

Thanks !

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Reliability Issues of IGBT based Converters - Indian...

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