Chris_Mi_handout
.pdf
Giving Speed Profile
•Solve for forces needed for given velocity profiles, such as UDDS and SAE driving cycles
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Example 1
•An electric vehicle has the following parameter values:
•m=692kg, CD = 0.2, AF = 2m2, C0 = 0.009,
•C1 = 1.75*10-6 s2/m2, ρ = 1.18 kg/m3, g = 9.81 m/s2
•The vehicle is going to accelerate with constant tractive force. Maximum force that can be provided by the vehicle drive line is 1500N.
–(a) find terminal velocity as a function of FT and plot it
–(b) if FT 500N, find VT, plot v(t), and calculate the time required to accelerate to 60mph
–(c) Calculate the instantaneous and average power corresponding to 0,98 VT.
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Solutions to Example 1 |
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POW1 |
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nx |
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pCDAF |
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GAIN |
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C11 |
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GAIN |
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2DGraphSel1 |
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FTR |
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SIGN1 |
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MUL1 |
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52.00 |
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CONST |
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FAD=0.5*p*CD*AF*V^2 |
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SUM3 |
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grade |
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mg |
m_1 |
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40.00 |
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Velocity |
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CONST |
SINE |
GAIN |
GAIN |
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I |
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FCT_SINE1 |
Fgxt=mg*sin(beta) |
INTG1 |
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C1 |
SUM2 |
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GAIN |
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Shee... |
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I |
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PowerINTG2 |
Energy |
20.00 |
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C0 |
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MUL2 |
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mg1 |
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CONST |
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GAIN |
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Froll=mg*(Co+C1*V^2) |
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SUM1 |
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MUL3 |
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0 |
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0 |
100.00 |
189.00 |
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CONST |
N0018 |
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Speed |
GAIN |
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FTR |
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GAIN1 |
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Example 2
•An electric vehicle has the following parameter values:
•m = 800kg, CD = 0.2, AF = 2.2m2, C0 = 0.008,
•C1 = 1.6*10-6 s2/m2, density of air ρ = 1.18 kg/m3, and acceleration due to gravity g = 9.81 m/s2
•The vehicle is on level road. It accelerates from 0 to
65mph in 10 s such that its velocity profile is given by
v(t) = 0.29055t 2 |
0 ≤ t ≤10s |
–(a) Calculate FTR(t) for 0 < t < 10 s
–(b) Calculate PTR(t) for 0 < t < 10 s
–(c) Calculate the energy loss due to non conservative forces Eloss.
–(d) Calculate ∆eTR.
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Solutions to Example 2
Speed
Tractive |
Energy |
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Summary
•Vehicle performance can be simulated using simulation tools such as Simplorer or Simulink, based on vehicle dynamic equations
•Vehicle performance can include
–Simulating vehicle speed, acceleration, and gradeability for given traction force
–Simulating vehicle performance for a given velocity profile by controlling the traction force
–Determine the required traction effort for a given velocity profile (driving cycles), acceleration and gradeability requirement
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10
Hybrid Electric Vehicles: Control,
Design, and Applications
Prof. Chris Mi
Department of Electrical and Computer Engineering
University of Michigan - Dearborn
4901 Evergreen Road, Dearborn, MI 48128 USA
email: chrismi@umich.edu
Tel: (313) 583-6434
Fax: (313)583-6336
Part 4
Energy Sources and Energy Storage
2
Contents
zComparison of energy sources
zOnboard energy storage
zEnergy converters
zBattery
zFuel cell
zUltra-capacitors
zFlywheels
zOther renewable energy sources
3
Energy Source, Energy
Converter, and Energy Storage
zEnergy refers to a source of energy, such as gasoline, hydrogen, natural gas, coal, etc.
zRenewable energy source refers to solar, wind, and geothermal, etc.
zEnergy converter refers to converting energy from one form of energy source to another form, such as electric generator, gasoline/diesel engine, fuel cell, wind turbine, solar panel, etc.
zEnergy storage refers to intermediate devices for temporary energy storing, such as battery, water tower, ultra-capacitor, and flywheel.
4
Comparison of Energy
Sources/storage
Energy |
Nominal Energy |
source/storage |
Density (Wh/kg) |
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Gasoline |
12,300 |
Natural gas |
9,350 |
Methanol |
6,200 |
Hydrogen |
28,000 |
Coal (bituminous) |
8,200 |
Lead-acid battery |
35 |
Sodium-sulfur battery |
150-300 |
Flywheel (steel) |
12-30 |
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Why Battery
zBatteries
-Popular choice of energy source for EV/HEVs
-Desirable characteristics of batteries are:
High-peak power
High specific energy at pulse power
High charge acceptance
Long calendar and cycle life
-Extensive research on batteries
There is no current battery that can deliver an acceptable combination of power, energy and life cycle for highvolume production vehicles
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z
z
z
Battery Basics
Constructed of unit cells containing chemical energy that can be converted to electrical energy
Cells can be grouped together and are called a battery module
Battery modules can be grouped together in a parallel or serial combination to yield desired voltage/current output and are referred to as a battery pack.
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e- |
Charge |
Discharge |
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N |
P |
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Ion |
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migration |
electrolyte
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Battery Cell Components
zPositive Electrode
-oxide or sulfide or some other compound that is capable of being reduced during cell discharge
zNegative Electrode
-a metal or an alloy that is capable of being oxidized during cell discharge
-Generates Electrons in the external circuit during discharge
zElectrolyte
-medium that permits ionic conduction between positive and negative electrodes of a cell
-must have high and selective conductivity for the ions that take part in electrode reactions
-must be a non-conductor for electrons in order to avoid selfdischarge of batteries.
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Battery Cell Components
zSeparator
-Is an layer of electrically insulating material, which physically separates electrodes of opposite polarity
-Separators must be permeable to the ions of the electrolyte and may also have the function of storing or immobilizing the electrolyte
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Battery Types
zPrimary Battery
-Cannot be recharged. Designed for a single discharge
zSecondary Battery
-Batteries that can be recharged by flowing current in the direction opposite of discharge
Lead-acid (Pb-acid)
Nickel-cadmium (NiCd)
Nickel-metal-hydride (NiMH)
Lithium-ion (Li-ion)
Lithium-polymer (Li-poly)
Sodium-sulfur
Zinc-air (Zn-Air)
Secondary batteries are primary topic for HEV/EV’s
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Batteries: In Depth
Battery |
Energy Density |
Energy Density |
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(Wh/kg) Theoretical |
(Wh/kg) |
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Practical |
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Lead-acid |
108 |
50 |
Nickel-cadmium |
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20-30 |
Nickel-zinc |
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90 |
Nickel-iron |
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60 |
Zinc-chlorine |
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90 |
Silver-zinc |
500 |
100 |
Lithium metal sulphide |
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170 |
Sodium-sulfur |
770 |
150-300 |
Aluminum-air |
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300 |
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Lead Acid Battery
zFirst lead acid battery produced in 1859
zIn the early 1980’s, over 100 million lead acid batteries produced per year
zLong Existence due to :
-Relatively low cost
-Availability of raw materials (lead, sulfur)
-Ease of manufacture
-Favorable electrochemical characteristics
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Cell Discharging
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Cell Discharging
zPositive Electrode Equation
-PbO2+4H++SO42-+2e ÆPbSO4+2H2O
zNegative Electrode Equation
-Pb+ SO42-ÆPbSO4+2e.
zOverall Equation
-Pb+PbO2+2H2SO4Æ2PbSO4 +2H2O
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