Lakmal Karunarathne An Intelligent Power Management System for Unmanned Aerial Vehicle ...

247 Pages·2012·40.68 MB·English

CRANFIELD UNIVERSITY
Defence College of Management and Technology
DepartmentofEngineering&AppliedScience
PhD Thesis
AcademicYear2012
Lakmal Karunarathne
An Intelligent Power Management System for
Unmanned Aerial Vehicle Propulsion
Applications
Supervisor
Dr J.T. Economou
copyright⃝cCranfieldUniversity2012.Allrightsreserved.Nopartofthispublicationmaybereproducedwithoutwrittenpermissionofthe
copyrightholder.

Abstract
ElectricpoweredUnmannedAerialVehicles(UAVs)haveemergedasapromi-
nentaviationconceptduetotheadvantageoussuchasstealthoperationand
zeroemission. Inaddition,fuelcellpoweredelectricUAVsaremoreattrac-
tive as a result of the long endurance capability of the propulsion system.
Thisdissertationinvestigatesnovelpowermanagementarchitectureforfuel
cell and battery powered unmanned aerial vehicle propulsion application.
The research work focused on the development of a power management
system to control the hybrid electric propulsion system whilst optimizing
thefuelcellairsupplyingsystemperformances.
The multiple power sources hybridization is a control challenge associated
withthepowermanagementdecisionsandtheirimplementationinthepower
electronic interface. In most applications, the propulsion power distribu-
tion is controlled by using the regulated power converting devices such as
unidirectional and bidirectional converters. The amount of power shared
withtheeachpowersourceisdependedonthepowerandenergycapacities
of the device. In this research, a power management system is developed
for polymer exchange membrane fuel cell and Lithium-Ion battery based
hybrid electric propulsion system for an UAV propulsion application. Ini-
tially, the UAV propulsion power requirements during the take-off, climb,
endurance,cruisingandmaximumvelocityaredetermined. Apowerman-
agement algorithm is developed based on the UAV propulsion power re-
quirement and the battery power capacity. Three power states are intro-
duced in the power management system called Start-up power state, High
power state and Charging power state. The each power state consists of
thepowermanagementsequencestodistributetheloadpowerbetweenthe
battery and the fuel cell system. A power electronic interface is developed
withaunidirectionalconverterandabidirectionalconvertertointegratethe
fuel cell system and the battery into the propulsion motor drive. The main
objective of the power management system is to obtain the controlled fuel
cellcurrentprofileasaperformancevariable. Therelationshipbetweenthe
fuel cell current and the fuel cell air supplying system compressor power
isinvestigatedandareferencedmodelisdevelopedtoobtaintheoptimum
compressor power as a function of the fuel cell current. An adaptive con-
troller is introduced to optimize the fuel cell air supplying system perfor-
mancesbasedonthereferencedmodel. Theadaptiveneuro-fuzzyinference
system based controller dynamically adapts the actual compressor operat-
ingpowerintotheoptimumvaluedefinedinthereferencemodel. Theon-
linelearningandtrainingcapabilitiesoftheadaptivecontrolleridentifythe
nonlinearvariationsofthefuelcellcurrentandgenerateacontrolsignalfor
thecompressormotorvoltagetooptimizethefuelcellairsupplyingsystem
performances.
Thehybridelectricpowersystemandthepowermanagementsystemwere
developed in real time environment and practical tests were conducted to
validatethesimulationresults.
Acknowledgements
I would like to extend my heartily gratitude to my supervisor, Dr. John
Economou for giving me the PhD research opportunity in Cranfield Uni-
versity. I appreciate all the guidance, encouragement and support given
by John throughout my time at Cranfield. As a perceptive lecturer, John’s
comments, feedbacks and suggestions were extremely helpful to focus on
my research objectives. In addition, the support given for publishing the
researchworksininternationalconferencesandjournalswasadmirable.
I am pleased to appreciate the constructive comments given by Professor
Jiabin Wang and Dr. Craig Lawson during the viva. I would like to thanks
PhDthesiscommitteeandProfessorKevinKnowleswhowerealwayssup-
porting and guiding me throughout the project. It is my pleasure to thank
ShrivenhamCampustechnicalstaffmembers,Ms. StaceyPaget,Mr. David
WaselyandMr. BarryGray.
My heartfelt gratitude goes to my parents, sister, brother and brother in-
law who are always looking forward for a bright future for me. Finally,
a graceful appreciation goes to my wife Kusum, for encouraging me and
sharingjoyfulthoughtsevenIwasfarawayfromhersight.
Contents
Contents i
ListofFigures vii
ListofTables xiii
Nomenclature xviii
1 Introduction 1
1.1 ResearchBackground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 ElectricPropulsionandPowerManagement . . . . . . . . . . . . . . . . 3
1.3 FuelCellControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 ResearchObjectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 ControlApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.6 OverviewofDissertation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2 LiteratureReview 11
2.1 LiteratureReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
i
CONTENTS
2.2 ElectricPropulsionTechnology . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3 ElectricPropulsioninAerospaceApplications . . . . . . . . . . . . . . . 14
2.4 FuelCellandBatteryHybridElectricSystem . . . . . . . . . . . . . . . . 18
2.4.1 HybridSystemPowerManagement . . . . . . . . . . . . . . . . . 19
2.5 IntelligentPowerManagement . . . . . . . . . . . . . . . . . . . . . . . . 25
2.5.1 AdaptiveNeuroFuzzyControl . . . . . . . . . . . . . . . . . . . . 26
2.6 FuelCells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.6.1 FuelCellHistory . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.6.2 FuelCellTypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.6.3 PEMFuelCellDevelopment . . . . . . . . . . . . . . . . . . . . . 35
2.7 PEMFCSystemControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3 PEMFuelCellSystemsand
CathodeDynamics 41
3.1 PEMFuelCells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
3.2 CellVoltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
3.2.1 OpenCircuitVoltage . . . . . . . . . . . . . . . . . . . . . . . . . . 44
3.2.1.1 PressureEffect . . . . . . . . . . . . . . . . . . . . . . . . 45
3.2.1.2 TemperatureEffect . . . . . . . . . . . . . . . . . . . . . 47
3.3 PEMFuelCellPolarization . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3.3.1 ExchangeCurrentDensity . . . . . . . . . . . . . . . . . . . . . . . 48
3.3.2 ActivationLoss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.3.3 OhmicLoss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.3.4 ConcentrationLoss . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.3.5 PEMFuelCellOperationalVoltage . . . . . . . . . . . . . . . . . 53
3.4 CathodeDynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.4.1 AirFlowRate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.5 AirSupplySystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.5.1 AirPressurization . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.6 FuelCellNetPower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
3.6.1 VoltageGain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.6.2 NetPowerGain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
ii
CONTENTS
4 UAVPropulsionPower
Requirements 63
4.1 UAVMissionProfile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.1.1 LongEnduranceMission . . . . . . . . . . . . . . . . . . . . . . . 65
4.2 UAVPerformanceRequirements . . . . . . . . . . . . . . . . . . . . . . . 66
4.3 TotalAircraftWeight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.4 Take-offPerformances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.4.1 RateofClimb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.5 AircraftLevelFlightOperation . . . . . . . . . . . . . . . . . . . . . . . . 73
4.6 MissionMaximumVelocities . . . . . . . . . . . . . . . . . . . . . . . . . 74
4.7 PropellerEfficiencyandMotorShaftPower . . . . . . . . . . . . . . . . . 75
4.7.1 DCMotorandPropellerMatching . . . . . . . . . . . . . . . . . . 76
4.7.2 MissionPowerProfileforLongEnduranceMission . . . . . . . . 78
4.8 RangeoftheMission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5 ElectricPropulsionSystem 83
5.1 ElectricPropulsionSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.2 PermanentMagnetBrushlessDCmotor . . . . . . . . . . . . . . . . . . . 84
5.2.1 OperationalPrincipals . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.2.2 MotorControlApproach . . . . . . . . . . . . . . . . . . . . . . . 89
5.2.3 MotorSpecifications . . . . . . . . . . . . . . . . . . . . . . . . . . 91
5.3 DCBusPower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
5.4 BatterySystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
5.4.1 BatteryCharacteristics . . . . . . . . . . . . . . . . . . . . . . . . . 96
5.4.2 BatterySizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
5.5 PowerConverters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
5.6 PEMFuelCellSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
5.7 SimulationModels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
6 IntelligentPowerManagement 107
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
6.2 PowerManagementSystem . . . . . . . . . . . . . . . . . . . . . . . . . . 108
6.2.1 Start-upState . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
6.2.2 ChargingState . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
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CONTENTS
6.2.3 HighPowerState . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
6.3 FuelCellPowerConditioningUnit . . . . . . . . . . . . . . . . . . . . . . 114
6.3.1 UnidirectionalConverterVoltageandCurrentLimits . . . . . . . 115
6.4 BDCVoltageandCurrent . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
6.5 OperationPrinciple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
6.5.1 VoltageModeController . . . . . . . . . . . . . . . . . . . . . . . 117
6.5.2 CurrentModeController . . . . . . . . . . . . . . . . . . . . . . . 118
6.6 Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
6.6.1 FiniteStateMachineSimulation . . . . . . . . . . . . . . . . . . . 120
6.6.2 Start-upStateTransitions . . . . . . . . . . . . . . . . . . . . . . . 121
6.6.3 HighPowerStateTransitions . . . . . . . . . . . . . . . . . . . . . 122
6.7 SimulationResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
6.7.1 CaseStudy(I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
6.7.2 CaseStudy(II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
7 FuelCellControland
PowerManagement 135
7.1 FuelCellSystemControlApproaches . . . . . . . . . . . . . . . . . . . . 136
7.2 AdaptiveControlStrategy . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
7.3 ANFISControllerOperation . . . . . . . . . . . . . . . . . . . . . . . . . . 141
7.3.1 FuzzyLogicDecisions . . . . . . . . . . . . . . . . . . . . . . . . . 143
7.3.1.1 FuzzificationInterface . . . . . . . . . . . . . . . . . . . . 143
7.3.1.2 RuleBaseSystem . . . . . . . . . . . . . . . . . . . . . . 144
7.3.1.3 FuzzyInferenceMachine . . . . . . . . . . . . . . . . . . 145
7.3.1.4 DefuzzificationInterface . . . . . . . . . . . . . . . . . . 146
7.3.2 AdaptiveProcess . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
7.3.3 ANFISMATLABModel . . . . . . . . . . . . . . . . . . . . . . . 150
7.4 CompressorandMotorModels . . . . . . . . . . . . . . . . . . . . . . . . 153
7.4.1 CompressorMap . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
7.5 Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
7.5.1 ANFISResults. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
7.5.2 PlantResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
7.5.3 CompressorPowerComparison . . . . . . . . . . . . . . . . . . . 165
iv
CONTENTS
8 PowerConvertersDesign
andControl 169
8.1 DCBusVoltageRegulation . . . . . . . . . . . . . . . . . . . . . . . . . . 170
8.2 UnidirectionalPowerConverterTopology . . . . . . . . . . . . . . . . . . 172
8.2.1 UDCTheoryofOperation . . . . . . . . . . . . . . . . . . . . . . 173
8.2.2 UnidirectionalPowerConverterDesign . . . . . . . . . . . . . . 175
8.2.2.1 InductorDesign . . . . . . . . . . . . . . . . . . . . . . . 176
8.2.2.2 DCBusCapacitance . . . . . . . . . . . . . . . . . . . . . 179
8.3 BidirectionalConverterTopology . . . . . . . . . . . . . . . . . . . . . . . 180
8.3.1 BDCTheoryofOperation . . . . . . . . . . . . . . . . . . . . . . . 181
8.3.2 BidirectionalConverterDesign . . . . . . . . . . . . . . . . . . . 182
8.3.2.1 BDCBoostModeOperation . . . . . . . . . . . . . . . . 182
8.3.2.2 BDCBuckModeOperation . . . . . . . . . . . . . . . . 185
8.3.2.3 Inductance . . . . . . . . . . . . . . . . . . . . . . . . . . 186
8.3.3 LVSideCapacitance . . . . . . . . . . . . . . . . . . . . . . . . . . 186
8.4 PulseWidthModulationandEmbeddedControl . . . . . . . . . . . . . . 188
8.4.1 MicrocontrollerPWMSignalControl . . . . . . . . . . . . . . . . 190
9 Experiments,Resultsand
Discussions 193
9.1 TheHybridElectricExperimentalSetup . . . . . . . . . . . . . . . . . . . 193
9.2 Experiment(1): Start-UpStateTest . . . . . . . . . . . . . . . . . . . . . . 194
9.2.1 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
9.2.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
9.2.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
9.3 Experiment(2): HighPowerandChargingPowerStatesTest . . . . . . . 201
9.3.1 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
9.3.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
9.3.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
10 ConclusionandFuturework 207
10.1 PowerManagement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
10.2 FuelCellControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
10.3 PotentialFutureResearch . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
v