smart embedded voltage control sensor for fc tools09 ......série1 série2 série3 cell voltage (mv)...

Laboratoire d' Intégration des Systèmes et des Technologies1

Alain [email protected]

CEA LIST

Smart embedded Voltage Control Sensor for individual elements of o fuel cell stack

FC_tools 09 TrondheimFrancis ROY

[email protected]

PAN-HPAN-H

Direction de la Recherche et de l’Innovation Automobile


FISYPAC project

FiSYPAC is the first project which leads to the vehicle integration of GENEPAC fuel cell stacks.

GENEPAC technology :

high performances 1.5kW/L and 1kW/kg

Technical Achievements :

Speed:155 km/h H2

= 1,1kg/100km Autonomy :500 km

Vehicle architecture :

Electrical motor

Li-Ion battery (75-500kms)

Charged by recovering energy

High pressure storage tank 1.5kW/L

1kW/kg

FCS on-line features:

60°-85°C

20-140A

10-16 bars on H2

entrance

50% of humidity

FISY

PAC

Life

tim

e im

prov

emen

tFISYPAC

Staionary

performance


Outline

Fisypac

: the fuel cell controlSpecification of monitoring moduleDesign of the moduleTest and validationsNew approach with sensors based on GMRDesigns Tests and validationsConclusions


FISYPAC: the fuel cell

control

Voltage control dispersion – 0,3V to 1,28V for an individual cell– 38,4V to 153,6V for the stack)

Resolution – +/-1% from 60°C to 85°C (nominal

temperature) => +/-10mV– +/-5% from -20°C to 60°C (intermediate)

Alarm thresholds– 0,4V information / 0,3V emergency

Control loop– 500ms

Board mechanical constraints– Screwed on stack back-bone – No compatibility between electronic space

common standards and Individual cell plug: minimum flat cable wiring

– Arrangement to equilibrate flat cable wiring between cells and board

Galvanic insulation– Simple opto

electronic components assume 1500V galvanic insulation between stack (350V with large tolerance) and vehicle grounded units

Board organization– Induced a splitting into three modules of the

functions embedded on the boardCAN networking

– CAN 1 : for each fuel cell emergency frames with alarm and emergency bits positioned when thresholds are crossed

– CAN 2 : for each fuel cell current voltage values

Data reading collected from cell wires coming from upper part A

Data reading collected for cell wires coming from lower part B

Reading and diagnosys system

CAN_1CAN_2

12V

Treatments and Diagnosis module

Opto coupling insulation

Opto coupling insulation

A

A

B

B


FISYPAC : transfer

mechanism

Galvanic insulation fixed to 1500V between fuel cells and 12V battery

Galvanic insulation fixed to 1500V between fuel cells and 12V battery

Opto-electronic barrelOpto-electronic barrel

V/F conversion Counter

First conversion: linearity, few influence of temperature

100100100

Second conversion: using counter functions of the computer

Computer

• analog signals are affected by emissivity and photo current restitution in presence of temperature

• binary signals are less sensible to opto barrel

Fuel Cell


FISYPAC: cell

for measuring

Measured cell = PR(i+1)

Ground PR(i)

Supply cell = PR(i+20) AA extern supply

AM extern ground

AS converted cell voltage

AC(i) shut down

Opto barrel

Regulator

Cell supplyV/F

conversion

Opto barrel

Opto barrel

Regulator

V/F conversion

Measured cell

Ground cell

Printed

board

mock-up

Cell supply

Measured cell

Ground cell


FISYPAC : scanning, treatment and transfer

Prototyping board (as near as possible final embedded board)

– ARM MAC7111 (automotive guarantees)– I/O, timers– CAN– JTAG probe for downloading and

debugging– Development PC with debuggind,

dowlnoading, compiler and CAN interface

Binary to counted signals– Best choice for timer conversion functions

Test bench – combining mock-up with 12 measurements

cells, prototype board and sell simulation (supply)

– Embedded software nearby FISYPAC application

Results – For each measured cell, linearity of computed

data versus analog supply simulating cell voltage

• External supply to replace fuel cell• 10mV increments to verify accuracy and

repeatability– Computation to determine coefficients of linear

function which identify the transfer response of measurement cell

– Control of emergency thresholds– CAN frames organization (automotive protocol)

ARM MAC7111microcontroller

Available I/O and counters

2 CAN drivers

JTAG debug


Monitoring module : some

results

0

500

1000

1500

2000

2500

3000

0 1000 2000 3000 4000 5000 6000 7000

Digital counting

Série1 Série2 Série3

Série7 Série9Cell v

olta

ge (m

V)

Mock-up validation– Precision < 10mV effective– No significant variation du to temperature or

batches dispersion– Efficient calibration

Convert. tension/fréquence AD654_circuit 1, régulateur LM2936 et optocoupleur HCPL063L à différents paliers de température (tens. entrée conv. = 0,6V, tens. sortie opto. = 3,3V)

58550

58600

58650

58700

58750

58800

58850

5 10 15 20 25

Tension entrée régulateur (V)

Fréq

uenc

e so

rtie

opto

coup

leu

fréq.@85°Cfréq.@60°Cfréq.@20°Cfréq.@0°Cfréq.@-20°C


Computed voltage– Computed voltage restitute correct cell voltage– Occurrence of event (modification of threshold voltage, exchange of

batteries– Without further temperature tests

0

200

400

600

800

1000

1200

1400

1 101 201 301 401Scrutations

VOIE_0 VOIE_1 VOIE_2VOIE_3 VOIE_4 VOIE_5VOIE_6 VOIE_7 VOIE_8VOIE_9 VOIE_10 VOIE_11

Com

pute

d ce

ll vol

tage

(mV)

New threshold (300mV)

0

200

400

600

800

1000

1200

1400

1 101 201 301 401Scanning loop

VOIE_0 VOIE_1 VOIE_2VOIE_3 VOIE_4 VOIE_5VOIE_6 VOIE_7 VOIE_8VOIE_9 VOIE_10 VOIE_11

Com

pute

d ce

ll vol

tage

(mV)

Changing of battery n°10


FISYPAC : final board

Prototype board– Design based of 12 cells mock-

ups– Use of printed boards layers to

equilibrate charge of the pile and access to the counters of treatment module

– calibration of all elements – Final validation of embedded

software (automotive protocol PSA)

– Test and validation at LITEN facility

– Test and validation in-situ in automotive conditions

• In lab conditions• On-going on road conditions

Automatic

purge of cells

CAN connectors

JTAGconnec

tors

Full remote

on-

line monitoring

Futur on-line monitoring


640660680700720740760780800820

0 40 80 120 160 200 240Cell identifiers (pile FISYPAC)

-40

-20

0

20

40

60

carte bancdelta

Com

pute

d ce

ll vo

ltage

(mV) D

ifference (mV)

840

860

880

900

920

940

0 40 80 120 160 200 240Cells identifers (FISYPAC stack)

-40-20020406080100

prototype boardPSA facilityDifferenceC

ompu

ted

volta

ge(m

V) Diffrence(m

V)

600

700

800

900

1000

0 20 40 60 80 100 120Cell identifiant (carte 1)

Com

pute

d ce

ll vo

ltage

(mV)

Diagnosys board

Flat cable to the stack

Ombilic of flat cables

Tests on LITEN facility


FISYPAC: GMR technology

Features:

• a current circulating into bias lines induces a magnetic field detected by resistors which value depend of the magnetic field encountered (nanned GMR).

•The magnetic field is not affected by the insulation layers between bias lines and GMR resistor, which allows an intrinsic galvanic insulation

•The linearity of the conversion is very efficient

Individual fuel cell

Bias current Amplifiers

100100100

CA/N ComputingGMR

-2

-1,5

-1

-0,5

0

0,5

1

1,5

2

-70 -50 -30 -10 10 30 50 70

Ibias (mA)

U (V

)

1mA1mA2mA2mA2.96mA2.96mA3mA3mA4mA4mA4,44mA4,44mA

Vsup Bias lines

Variable resistors

Ibias

Vstack

or

Vcell

GMR cell VGMR

ground


FISYPAC : behavior

of a single GMR cell

Behavior of a single GMR– Very linear comportment of cell

voltage conversion– Inherent low offset– Sensitivity to temperature

• Appears as homogeneous and linear

• Computed correction (treatment module)

• Compensation by technology• Not possibility to evaluate lot

effect production– Next step, design of a barrel

Single GMR cell

Bias line and cell voltage simulation

Amplification

-40

-20

0

20

40

0 0,5 1 1,5 2 2,5 3

VIN+ - VIN-(mV à 20°C)VIN+ - VIN-(mV à 40°C)VIN+ - VIN-(mV à 60°C)VIN+ -VIN- (mV à 85°C)VIN+ - VIN-(mV à 0°C)VIN+ - VIN- (mV à -20°C)

ESSAI

Vin+

- Vi

n- /

mV

Vcel / V


FISYPAC : behavior

of a single barrel

Barrel design– Could

be

seen

as nano and

micro design and production with

various

processes

• Low

offset• Few drifts observed

in tempature

environments• Some

drifts on bias

resistors– No dispersion on the barrel

Insulation

difficulties

Barrel of 8 GMR cells

Bias lines

GMR outputs

1,35

1,45

1,55

1,65

1,75

0 0,5 1 1,5 2 2,5 3cell voltage (V)

V+0°C V-0°CV+20°C V-20°CV+-20°C V--20°CV+40°C V-40°CV+60°C V-60°CV+85°C V-85°C

VGMR

(V)


FISYPAC: the GMR module

Design of an hybrid model – GMR barrel – Discrete instrumentation stage

Packaging – Multilayer– Interconnection

Results– Linearity– Existing offset– Accuracy

GMR barrel

A1_750 = -0,2834x + 1,8796R2 = 0,9995

A2_750 = -0,2739x + 1,7504R2 = 0,9996

A3_750 = -0,2803x + 1,6948R2 = 0,9996

A5_750 = -0,2353x + 1,8196R2 = 0,9996

A6_750 = -0,2411x + 1,7728R2 = 0,9997

A7_750 = -0,2454x + 1,6846R2 = 0,9996

A8_750 = -0,2426x + 1,761R2 = 0,9996

1

1,2

1,4

1,6

1,8

2

2,2

2,4

-1,5 -1 -0,5 0 0,5 1 1,5

Cell Voltage (V)

AMPL

I (V)


To conclude

Applications involving a large number of cells or stacks needs an efficient and faithful smart embedded control board to deal with

emergency technics

when single or multiple cells become degraded or failedOur on-line monitoring tools are involved in an automotive application?

Validation for validation is on-going. Recent GMR technology offers an appreciable opening to modern nano

or micro sensors for monitoring of cell or stack voltage (and probably other parameters not yet tracked). The prototype board will be soon produced and validate on 200-400 cells stacks.Nevertheless, as for electronic technologies, such an innovative

approach will deal with industries interest only when technologies become stable with a significant life-time. This will be done for designers and founders when an identified volume market will be appreciate.


The end…

Thank you for your attention!!

Curtesy

PSA

smart embedded voltage control sensor for fc tools09 ......série1 série2 série3 cell voltage (mv)...

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