Modeling, simulation, and concept studies of a fuel cell hybrid electric vehicle powertrain [Elektronische Ressource] / von Markus Özbek

Modeling, Simulation, and Concept Studies of a
Fuel Cell Hybrid Electric Vehicle Powertrain
Von der Fakult¨at fur¨ Ingenieurwissenschaften,
Abteilung Maschinenbau und Verfahrenstechnik
der
Universit¨at Duisburg-Essen
zur Erlangung des akademischen Grades
eines
Doktors der Ingenieurwissenschaften
Dr.-Ing.
genehmigte Dissertation
von
¨Markus Ozbek
aus
S¨ odert¨alje, Schweden
Gutachter: Univ.-Prof. Dr.-Ing. Dirk S¨ offker
Prof. Dr.-Ing. Dieter Schramm
Tag der mundlichen¨ Prufung:¨ 29. M¨arz 2010Dedicated to my grandfather
¨Musa Ozbek
1907 - 2010
who lived a long and prosperous lifeIV
Acknowledgement
The work presented in this thesis was initiated by the German federation of indus-
trial research associations (AiF) together with the German association of powertrain
technology (FVA) and conducted during my doctoral studies at the Chair of Dy-
namics and Control at the University of Duisburg-Essen.
First of all, I would like to thank my supervisor Univ.-Prof. Dr.-Ing. Dirk S¨ offker for
his great support, encouragement, and help. Without him, this work would never
initiate nor finish.
I would also like to thank Prof. Dr.-Ing. Dieter Schramm for his effort being the
co-reviewer for my thesis.
This work was conducted in collaboration with the Chair of Energy Technology
at the University of Duisburg-Essen and a great appreciation is given to rer.-nat.
Prof. Angelika Heinzel, Dr.-Ing. Jurgen¨ Roes, their technical support Jochen Binde-
mann, and especially my working partner Lars Wulb¨ eck.
I would like to thank all my long time working partners at the Chair of Dynamics
and Control; Hammoud Al-Joummaa, Kai-Uwe Dettmann, Dennis Gamrad, Frank
Heidtmann, Yan Liu, Matthias Marx, and Mahmud-Sami Saadawia for their help
and support and our secretaries Yvonne Vengels and Doris Schleithoff for their help
with the administration. I wish them all the best in their future work. I would also
like to thank all students who I supervised in their project works, bachelor-, and
master theses. This includes Nguyen Binh, Andr´e Heßling, Xinfeng Huang, Sebas-
tian Krins, Bertrand Teck Ping Ng, Yew Kok Poong, Adalbert Rudnicki, Theresia
Rusch, Tharsis Ghim Han Teoh, and Shen Wang. I wish them all good luck in their
studies.
Special thanks are given to my prior supervisor and mentor, Prof. Svante Gunnarsson
at the Chair of Automatic Control at Link¨ oping University in Sweden, for giving
me the interest for control technique.
Finally but mostly I would like to thank my brothers and sisters and especially my
parents whom without their love and support I would never be able to conduct this
work.
¨Duisburg, May 2010 Markus OzbekV
Contents
Nomenclature VIII
1 Introduction 1
1.1 Fuelcels.................................. 3
1.2 New powertrain technologies . . . . . . . . . . . . . . . . . . . . . . . 4
1.2.1 Hybridvehicles.......................... 5
1.2.2 Zero-emission electric vehicles . . . . . . . . . . . . . . . . . . 7
1.3 State-of-the-Art.............................. 8
1.4 Project goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2 Hardware-in-the-Loop test rig 10
2.1 Fuelcelsystem.1
R2.1.1 Ballard Nexapowermodule..................13
2.1.2 Alternativefuelcelsystem ...................14
2.1.3 Lifetimeoffuelcels .......................17
2.2 Energystorageaccumulators19
2.2.1 SuperCaps.............................19
2.2.2 Bateries..............................20
2.3 DC/DC-converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.4 Electricmotors..............................23
2.4.1 Drive-motor24
2.4.2 Load-motor25
2.5 Implementationandexperimentalstudies................25
2.5.1 Load profile implementation . . . . . . . . . . . . . . . . . . . 25
2.5.2 Vehicleimplementation......................27VI Contents
3 Modeling the hybrid powertrain 28
3.1 Fuelcelsystemmodel..........................28
3.1.1 PEMfuelcellstackmodel....................29
3.1.2 Air supply system model . . . . . . . . . . . . . . . . . . . . . 30
3.1.3 Temperaturedynamicsmodel..................35
3.2 SuperCapmodel .............................36
3.3 Batterymodel...............................38
3.3.1 Capacitymodel..........................38
3.3.2 Voltagemodel.40
3.4 DC/DC-converter model . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.5 Validationofthecomponentmodels...................44
3.5.1 Validationofthefuelcelmodel.................4
3.5.2 ValidationoftheSuperCapmodel................47
3.5.3 Validationofthebatterymodel.................50
3.5.4 Validation of the DC/DC-converter . . . . . . . . . . . . . . . 55
3.5.5 Validationofthehybridsystem.................57
4 Control of hybrid system components 59
4.1 Controloffuelcelsystems........................59
4.2 Controlofthefuelcelsystem......................60
4.2.1 Efficiencyconstraint.61
4.2.2 Static Feed-Forward control . . . . . . . . . . . . . . . . . . . 62
4.2.3 Linearizationofthefuelcelmodel...............63
4.2.4 Optimalcontrol..........................64
4.2.5 Gain-schedulingcontrol .....................6
4.2.6 Hydrogenvalvecontrol......................67
4.3 Results...................................69
4.4 Control of DC/DC-converter . . . . . . . . . . . . . . . . . . . . . . . 73Contents VII
5 Parametrization and evaluation 75
5.1 Systemdesignfromgivenloadprofiles .................75
5.1.1 Degre-of-Hybridization(DoH) .76
5.1.2 BateriesorSuperCaps......................79
5.1.3 Sizing the SuperCaps of the hybrid system . . . . . . . . . . . 80
5.1.4 Simulationresults.........................82
5.2 Choiceoftopology............................83
5.2.1 Topology A: Basic topology . . . . . . . . . . . . . . . . . . . 83
5.2.2 TopologyB:Rangeextender...................84
5.2.3 TopologyC:Fulhybrid.....................86
5.2.4 Topology D: Extended topology . . . . . . . . . . . . . . . . . 88
5.3 Evaluation of the dynamics of the hybrid system . . . . . . . . . . . . 89
6 Powermanagement 93
6.1 Theory...................................93
6.2 PMI:Ratelimiter............................94
6.3 PMI:Maximumfuelcelpower.....................96
6.4 PMII:ConstantSoC-level .......................96
6.5 Experimentalresultsandevaluation...................96
7 Summary and outlook 102
7.1 Scientificcontribution ..........................102
7.2 Limitations................................103
7.3 Futureaspects...............................103
Bibliography 105VIII
Nomenclature
Constants
Symbol Parameter Unit Value
b Blower motor constant [Nms/rad] 2.3e-4cm
d Blower diameter [m] 0.0508c
k A Product between thermalst st
conductivity and conducting
surface area of stack [J/K] 6.0
k Blower motor constant [Nm/A] 0.089cm
k Blower motort [Vs/rad] 0.0752v
m C Product between mass andst p,st
specific heat capacity of stack [J/K] 2e4
m Vehicle total mass [kg] 201.3veh
n Number of fuel cells [-] 45fc
p Ambient pressure [Pa] 101325amb
p Blower p [Pa]cp
t Membrane thickness [cm] 3e-3m
2A Fuel cell active area [cm]50fc
2A Vehicle front area [m]0.83veh
C Vehicle drag coefficient [-] 0.37d
C Specific air heat capacity [J/kgK] 1004p,a
C Specific coolant heat capacity [ 4183p,cool
C Specific vapor heat capacity [J/kgK] 1860p,v
F Faraday constant [C] 96485
ΔG Difference of Gibbs free energyf
for fuel cell reactants [J/mol] 237.2e3
2J Inertia of blower motor [kgm ] 7.245946e-4cm
2J of blower and motor [kgm ] 7.25e-4cp
L Inductance of blower motor [H] 4.98e-3cm
M Vapor molar mass [kg/mol] 18.02e-3v
M Hydrogen molar mass 2e-3H2
M Nitrogen molar mass [kg/mol] 28e-3N2
M Oxygen molar mass [kg/mol] 32e-3O2
23N Avogadro’s number [-] 6.022x10
R Universal gas constant [J/molK] 8.3145
R Air gas constant [J/kgK] 286.9a
R Battery internal resistance [Ω] 0.08bat
R Blower motorcm
internal resistance [Ω] 0.32
R Vehicle gear ratio [m] 5gearNomenclature IX
Symbol Parameter Unit Value
R SuperCap internal resistance [Ω] 0.012i,sc
R Vapor gas constant [J/kgK] 461.5v
R Hydrogen gas constant 4124.3H2
R Nitrogen gast [J/kgK] 296.8N2
R gas constant 259.8O2
R Vehicle wheel radius [m] 0.223w
T Ambient temperature [K] 298amb
T Coolant water temperature [K] 353cool
T Blower inlet temp [K] 298cp,in
3V Anode volume [m ] 1.08e-4an
γ Air heat capacity ratio [-] 1.4a
δ Corrected pressure [-] 1
η Blower motor efficiency [%] 100cm
θ Corrected temperature [-] 298/288
3ρ Air density [kg/m]1.23a
ΔH Hydrogen higher heating value [J/kg] 141.9e9u,H2
Δ H condensation enthalpy of the wa- [J/kg] 2260e3v
ter
ΔS Reaction entropy [J/molK] -326.36X Nomenclature
Variables
Symbol Parameter Unit
E Fuel cell open circuit voltage [V]o,fc
i Blower motor current [A]cm
i SuperCap current [A]sc
i Fuel cell stack current [A]st
I Battery current [A]bat
2J Vehicle wheel inertia [kgm ]w
m Hydrogen mass in anode [kg]H2
m Nitrogen mass in cathode [kg]N2
m Oxygen mass in cathode [kg]O2
m Water mass in anode [kg]w,an
m Water mass in cathode [kg]w,ca
Ma Inlet mach number [-]
M Vehicle wheel torque from air resistance [Nm]