fmatter
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CONTENTS |
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xiii |
B.2.3 |
Dynamic Programming, 374 |
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B.2.4 |
Linear Quadratic Control, |
378 |
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B.3 Stochastic and Adaptive Control, |
381 |
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B.3.1 |
Minimum-Variance Prediction and Control, 382 |
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B.3.1.1 |
Minimum-Variance Prediction, 382 |
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B.3.1.2 |
Minimum-Variance Control, 385 |
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B.3.2 |
Self-Tuning Control, 387 |
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B.3.3 |
Model Reference Adaptive Control, 389 |
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B.3.4 |
Model Predictive Control, |
391 |
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B.4 Fault-Tolerant Control, 392 |
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B.4.1 |
Hardware Redundant Control, 394 |
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B.4.2 |
Software Redundant Control, 394 |
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References, 395 |
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Index |
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397 |
PREFACE
During the last decade, hybrid electric vehicles have come on the market and new techniques have been dramatically advanced and widely used. In the evolution of the design of hybrid vehicle systems, there exist several paramount challenges. These are driven by the stricter requirements for fuel economy and emissions and by progress in the technical development of power electronics, batteries, and other major components.
Hybrid electric vehicles, combining an internal combustion engine with one or more motors for propulsion, operate in the changing environments of different fuels, load levels, and weather conditions. Hybrid electric vehicle system engineers are now being challenged to expand their horizons and extend their concepts and methods not only so they can be applicable to incompletely modeled systems but also to the systems whose models are initially poorly defined but can be improved online during operation.
Modeling and control have played key roles in technological development, from overall system performance analysis to the calculation of manufacturing and servicing cost of new design. To articulate these challenges and encouraged by current hybrid vehicle system advancement, the author thought it necessary to publish a book on the hybrid electric vehicle system modeling and control.
The material assembled in this book is an outgrowth of my over ten years of work on hybrid vehicle research, development, and production at National Research Council Canada, Azure Dynamics and General Motors. This book is intended to contribute to a better understanding of hybrid vehicle systems and to present all the major aspects of hybrid vehicle modeling, control, simulation, performance analysis, and preliminary design.
xv
xvi |
PREFACE |
There are many good articles about hybrid vehicle system modeling, simulation, and control algorithms available. However, up until now, there has not been a book that more systemically and deeply explores the connections between performance analysis, modeling, and control design. The motivation behind this book has been to provide adequate coverage to meet the ever-increasing demand for engineers to look for rigorous methods for hybrid vehicle design and analysis. It is hoped that the sought-after conciseness and the selected examples illustrating the methods of the modeling, simulation, and control will achieve this.
The book consists of nine chapters and two appendices. Chapter 1 provides an introduction to hybrid vehicle system architecture, energy flow, and control of a hybrid vehicle system. Chapter 2 reviews the main components of a hybrid system and their characteristics, including the internal combustion engine, electric motor/generator, energy storage system, and fuel cell system.
Chapter 3 presents the detailed mathematical models of hybrid system components for system design and simulation analysis, including the internal combustion engine, transmission system, motor, generator, battery system, and vehicle body system and driver. The models presented in this chapter can be used for either individual component analysis or building a whole vehicle simulation system.
Chapter 4 introduces the power electronics and electric motor drives applied in hybrid vehicle systems. The characteristics of commonly used power electronic switches are presented first, and then the operation principles of the DC–DC converter and DC/AC inverter are introduced. The brushless DC motor and AC induction motor and their control principles are also introduced for hybrid vehicle applications. Plug-in charger design is presented in the last part of the chapter.
Chapter 5 addresses the energy storage system modeling and controls. The related algorithms play a very important role in hybrid vehicle systems because they directly affect the overall fuel economy and drivability and safety of a vehicle; however, due to the measurement availability, hybrid vehicle system engineers are facing technical challenges in the vehicle required algorithms. State-of-charge determination algorithms and the technical challenges faced in development are introduced. Then, the power capability algorithms and state- of-life algorithms are discussed. The hybrid vehicle cell balancing algorithm, battery cell core temperature estimation method, and battery system efficiency calculation are also presented.
Chapter 6 is concerned with the solution of energy management problems in the presence of different drive cycles. Both direct and indirect methods of optimization are discussed. The methods presented in this chapter can be treated as the most general and practical techniques for the solution of hybrid vehicle energy management problems.
Chapter 7 elaborates other control problems in hybrid vehicle systems, including active engine fluctuation torque dumping control, voltage ripple control in high-voltage buses, thermal control of the energy storage system, motor traction and anti-rollback control, and electric active suspension system control.
Chapter 8 discusses the characteristics of AC-120, AC-240, and rapid public plug-in charging for the emerging plug-in hybrid and pure battery-powered
PREFACE |
xvii |
vehicles. The impact of plug-in charging on electric grid and power distribution systems is presented. In addition, the various plug-in charging strategies, including the optimal charging strategy, are introduced.
Chapter 9 presents the techniques of sizing components and simulating system performance at the concept or predesign stage of a hybrid vehicle system. Typical test cycles related with hybrid vehicle systems are detailed, and the calculations of fuel economy and emissions are given.
Appendix A reviews system identification and the state and parameter estimation methods. The commonly used mathematical models are introduced for hybrid vehicle system control algorithm development. The recursive least-squares and generalized least-squares techniques are presented for parameter estimation. The Kalman filter and extended Kalman filter are also introduced to state estimation and joint parameter and state estimation. In addition, needed computation stability enhancement techniques of practical hybrid vehicle systems are presented.
Appendix B briefly introduces some advanced control methods which are needed to improve the performance of a hybrid electric vehicle system. These include system pole placement control, the objective function-based optimal control, dynamic programming-based optimal control, and minimum variance and adaptive control techniques for systems with stochastic behaviors. To enhance the reliability and safety of a hybrid vehicle system, fault-tolerant control strategies are also briefly introduced.
This book is written as an engineering reference book on hybrid vehicle system analysis and design. It is suitable for a training course on hybrid vehicle system development with supplemental materials. It should enable design engineers to understand hybrid vehicle system control algorithm design and development. It can also be used for both undergraduateand graduate-level hybrid vehicle system modeling and control courses. I hope that the efforts here succeed in helping you understand better this most interesting and encouraging technology.
WEI LIU, Ph.D., PE, P Eng
NOMENCLATURE
Ad |
Air mass density |
AH /C |
Heating/cooling surface area between battery pack and |
|
heating/cooling channel |
Ah |
Ampere-hour |
Ca |
Air density correction coefficient for altitude |
CapBOL |
Battery Ah capacity at beginning of life |
CapEOL |
Designed battery Ah capacity at end of life |
Cbat_life |
Battery life cost weight factor |
Cc |
Specific heat of coolant |
Cd |
Vehicle aerodynamic drag coefficient |
Cds |
Source-to-drain capacitance of MOSFET |
Cdiff |
Diffusion capacitance of second-order electrical circuit battery |
|
model |
Cdl |
Double-layer capacitance of the first order and second-order |
|
electrical circuit battery model |
Cdyn |
Dynamic capacitance of battery electrical circuit model |
Cele |
Electric power cost weight factor |
Cenergy_balance |
Imbalanced energy cost weight factor |
Cess |
Specific heat of battery system |
Cfuel |
Fuel cost weight factor |
Cgd |
Parasitic capacitance from gate to drain of MOSFET |
Cgs |
Parasitic capacitance from gate to source of MOSFET |
D |
Duty cycle of PWM control method |
Dcf |
Distance between center of gravity and front wheel of vehicle |
xix
xx |
NOMENCLATURE |
Dcr |
Distance between center of gravity and rear wheel of vehicle |
Ea |
Back electromotive force |
Ea |
Activation energy of battery |
F |
Faraday constant, number of Coulombs per mole of electrons |
|
(9.6485309 × 104 C · mol−1) |
Fa |
Frontal area of vehicle |
Factuator_max |
Maximum output force of actuator of active suspension system |
Fwf |
Friction force acting on front wheel of vehicle |
Fwr |
Friction force acting on rear wheel of vehicle |
Gactuator(s) |
Transfer function of actuator of active suspension system |
G(Cap) |
Decline of Ah capacity of battery system |
G(R) |
Increment of internal resistance of battery system |
H2 |
Hydrogen gas |
Hcg |
Height from center of gravity to road of vehicle |
Hgen d |
Battery heat generation |
Ibalancing_max |
Maximum balancing current of battery system |
IFAV |
Maximum average forward current |
IFRMS |
Maximum RMS forward current |
IFSM |
Maximum forward surge current |
IH |
Holding current of thyristor |
IGM |
Maximum peak positive gate current of thyristor |
Imax _chg |
Maximum allowable charge current of battery system |
Imax _dischg |
Maximum allowable discharge current of battery system |
J |
Motor rotor inertia |
Jaxle |
Lumped inertia on axle transferred from powertrain |
Jeng |
Lumped engine inertia |
Jfd |
Final drive inertia |
Jgr |
Gear box inertia |
Jmot |
Lumped motor inertia |
Jtc |
Lumped torque converter inertia |
Jwh |
Vehicle wheel inertia |
K |
Proportional gain of PID controller |
Kactuator |
Gain of actuator from input voltage to output force of active |
|
suspension system |
Ke |
Voltage constant of BLDC motor |
Km |
Torque constant of BLDC motor |
LiFePO4 |
Lithium iron phosphate |
Lm |
Magnetizing inductance |
Lr |
Rotor phase inductance |
Lr |
Load rate of torque converter |
Ls |
Motor stator phase inductance |
Mc |
Total coolant mass of energy storage system |
Mess |
Mass of energy storage system |
NC |
Teeth number of carrier of planetary gear set |
NOMENCLATURE |
xxi |
NR |
Teeth number of ring gear of planetary gear set |
NS |
Teeth number of sun gear of planetary gear set |
O2 |
Oxgen gas |
Pacc |
Lumped accessory power |
Pa_pct |
Acceleration pedal position in percentage |
Pbrake_pct |
Brake pedal position in percentage |
Pbat |
Battery power |
Pct |
Percentage grade ability |
Peng |
Engine power |
Pmot |
Motor power |
Pmax _chg_bat |
Maximum allowable battery charging power |
Pmax_dischg_bat |
Maximum allowable battery discharging power |
Pmax_prop_mot |
Maximum allowable motor propulsive power |
Pmax_regen_mot |
Maximum allowable motor regenerative power |
Ppump |
Operation power of heating/cooling system pump |
PVeh |
Vehicle demand power |
Q |
Battery reaction quotient |
Qc |
Surface-convection heat transfer |
˙ H /C |
Energy transfer rate of heater/chiller |
Q |
|
R |
Electrical resistance |
RBOL |
Battery internal resistance at beginning of life |
REOL |
Battery internal resistance at end of life |
Rct |
Charge transfer resistance of second-order electrical circuit |
|
battery model |
Rdiff |
Diffusion resistance of second-order electrical circuit battery |
|
model |
Rdyn |
Dynamic resistance of battery electrical circuit model |
Ress |
Internal resistance of battery system |
Rg |
Universal gas constant: R = 8.314472 J · K−1 · mol−1 |
Rint |
Battery cell internal resistance |
Rohm |
Ohmic resistance of battery electrical circuit model |
Rr |
Motor rotor phase resistance |
Rs |
Motor stator phase resistance |
Rwf |
Reaction force acting on front wheel vehicle |
Rwr |
Reaction force acting on rear wheel vehicle |
SOCinit |
Initial state of charge of battery |
SOCtarget |
Target state of charge of battery |
Tactuator |
Time constant of actuator from input voltage to output force |
Tc |
Coolant temperature |
Tc_init |
Initial coolant temperature |
Tc_sp |
Coolant temperature setpoint |
Td |
Derivative time constant of PID controller |
Tess |
Energy storage system temperature |
xxii |
NOMENCLATURE |
Tess_init |
Initial battery system temperature |
Tess_sp |
Temperature setpoint of energy storage system |
Ti |
Integral time constant of PID controller |
TJ |
Maximum junction temperature of power electronics |
TS |
Period of the PWM signal or sampling time period |
VBE |
Base–emitter voltage of bipolar transistor |
VCE |
Collector–emitter voltage of bipolar transistor |
VDRM |
Peak repetitive forward blocking voltage of thyristor |
Vdynamic |
Voltage on dynamic component of battery electrical circuit |
|
model |
VGM |
Maximum peak positive gate voltage of thyristor |
VGS |
Gate voltage of MOSFET |
Vmax |
Maximum allowable battery system terminal voltage |
Vmin |
Minimum allowable battery system terminal voltage |
V 0 |
Standard cell potential |
Vo |
Potential of battery electrical circuit model |
Voc |
Open-circuit voltage |
VR |
Maximum reverse voltage of power diode |
VRRM |
Peak repetitive reverse blocking voltage of thyristor |
VRSM |
Nonrepetitive peak reverse voltage of thyristor |
VRWM |
Maximum working peak reverse voltage of power diode |
Vterminal |
Battery system terminal voltage |
a |
Acceleration |
fd |
Final drive ratio |
ffuel |
Fuel economy |
femi_CO |
Carbon monoxide emissions |
femi_HC |
Hydrocarbon emissions |
femi_NOx |
Nitrogen oxide emissions |
femi_PM |
Particulate matter emissions |
gCO_hot |
Hot carbon monoxide emission rate |
gfuel_hot |
Hot fuel economy rate |
gHC_hot |
Hot hydrocarbon emission rate |
gm |
MOSFET transconductance |
gNox_hot |
Hot nitrogen oxide emission rate |
gPM_hot |
Hot particulate matter emission rate |
gr |
Gear ratio |
h |
Heat transfer coefficient |
hbat |
Battery heat transfer coefficient |
ids |
d axis or air-gap flux current of AC induction motor |
iqs |
q axis or torque current of AC induction motor |
iQs |
Stator quadrature-axis current of AC induction motor |
iDs |
Stator direct-axis current of AC induction motor |
iQr |
Rotor quadrature-axis current of AC induction motor |
iDr |
Rotor direct-axis current of AC induction motor |
NOMENCLATURE |
xxiii |
kaero |
Aerodrag factor |
kchg |
Charging power margin factor |
kd |
Distortion factor of plug-in charger |
krrc |
Rolling resistance coefficient |
ksc |
Road surface coefficient |
ksplit |
Split coefficient to engine and electric motor |
m˙ c |
Mass flow rate of coolant |
mv |
Manufacturer rated gross vehicle mass |
mv a |
Vehicle acceleration force |
mv g |
Gross weight of vehicle |
ne |
Number of electrons transferred in cell reaction |
rC |
Carrier radius of planetary gear set |
rds |
Source-to-drain resistance of MOSFET |
ro |
MOSFET output resistance |
rR |
Ring gear radius of planetary gear set |
rS |
Sun gear radius of planetary gear set |
rwh |
Effective wheel rolling radius |
sr |
Speed ratio of torque converter |
vQs |
Stator quadrature-axis voltage of AC induction motor |
vDs |
Stator direct-axis voltage of AC induction motor |
vQr |
Rotor quadrature-axis voltage of AC induction motor |
vDr |
Rotor direct-axis voltage of AC induction motor |
S |
Delta entropy of reaction |
ψ |
Motor rotor magnetic flux |
Qs |
Motor stator quadrature-axis flux linkage |
Ds |
Motor stator direct-axis flux linkage |
Qr |
Motor rotor quadrature-axis flux linkage |
Dr |
Motor rotor direct-axis flux linkage |
α |
Road incline angle |
λ |
Forgetting factor of recursive least-squares estimator |
λfuel |
Fuel economy temperature factor |
λCO |
Carbon monoxide emission temperature factor |
λHC |
Hydrocarbon emission temperature factor |
λNOx |
Nitrogen oxide emission temperature factor |
λPM |
Particulate matter emission temperature factor |
δ(t) |
Dirac delta function |
ηbat |
Battery efficiency |
ηchg |
Battery charge efficiency |
ηfd |
Final drive efficiency |
ηgr |
Gear box efficiency |
ηH/C |
Heater/chiller efficiency |
ηmot |
Motor efficiency |
ηpt_eng |
Engine power drivetrain efficiency |
xxiv |
NOMENCLATURE |
ηpt_mot |
Electric motor power drivetrain efficiency |
ηtc |
Torque converter efficiency |
μA |
Membership function of fuzzy logic |
τa |
Acceleration torque |
τaccess |
Lumped torque of mechanical accessories |
τC |
Coulomb friction torque |
τcct |
Closed-throttle torque of engine |
τcom |
Compression torque |
τcrank |
Cranking torque |
τdemand |
Vehicle demand torque |
τe |
Electromagnetic torque |
τeng |
Engine torque |
τload |
Load torque |
τloss |
Lumped loss torque |
τmot |
Motor torque |
τregen |
Regenerative torque |
τr |
Torque ratio of torque converter |
τs |
Static friction torque |
τtrac |
Traction torque from powertrain |
τv |
Viscous friction torque |
ω |
Vehicle wheel angular velocity |
ωc |
Angular velocity of carrier of planetary gear set |
ωeng |
Angular velocity of engine |
ωmax _eng |
Maximum allowable angular velocity of engine |
ωmot |
Angular velocity of motor |
ωmax _mot |
Maximum allowable angular velocity of motor |
ωR |
Angular velocity of ring gear of planetary gear set |
ωs |
Synchronous speed of AC induction motor |
ωs |
Angular velocity of sun gear of planetary gear set |