1 regenerative electric flight synergy and integration of dual-role machines j. philip barnes aiaa...
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Regenerative Electric FlightSynergy and Integration
of Dual-role MachinesJ. Philip Barnes AIAA 2015-1302
07 Jan 2015 original 23 Feb 2015 Update
Adobe Acrobat Document
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Presentation Contents
Regenerative Electric-powered Flight J. Philip Barnes
The visionaries
Brushless MGM-GiGBT
VM
Power Electronics
Brushed MG
SynergyIntegration
WindpropRegenosoar
3
Hermann Glauert
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
“Consider the case of a windmill on an aeroplane”
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Paul MacCready
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
Regenerative electric flightconcept “with caution,” ‘99
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Presentation Contents
Regenerative Electric-powered Flight J. Philip Barnes
The visionaries
Brushless MGM-GiGBT
VM
Power Electronics
Regenosoar
Windprop
Brushed MG
• Angle of attack = 0, hub-to-tip • wr tanb = Vo Therefore:
• r tanb = Vo / w = R tan btip
• Approaches "Betz Condition“
Blade section Looking outboard,Blade at 3 o’clock
Cho
rd li
ne
b
Rotor velocity diagram - "Pinwheeling" & “Betz” conditions
Axial wind
Vo
Vo
Rotationalwind, w r
Rel
ativ
ew
ind
W1
b
Vo
W2
Hel
ical
wak
e
w r
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
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Windprop Blade Angle and Operational Mode
V
wr
b
W
Pinwheel
V
wr
L b
W
Propeller
V w
r -L
b
W
Turbine
Define: “Speed ratio,” s v / vpinwheel = v / [ wR tanbtip ]
Similar to advance ratio (J) but meaningful for 3 modes
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
J. Philip Barnes www.HowFliesTheAlbatross.com
• Non-rotational (axial) inflow• Axial velocity locally conserved • Final swirl imparted suddenly• Helical vortex wake, ea. blade• Wake ~ aligned with meanline• Wake-induced velocity (Vi)
• Glauert: 2Viq at "rotor out"• Absolute velocity (V) increased• Relative wind (W) decreased• Immediate static pressure rise
Propeller blade - comprehensive velocity diagram
Relativewind W1
a
Wq w r - Viq
f
V1
z Ze
ro-li
ft lin
e
Rotational wind
Axial wind
V1 Vo+Vix
Hel
ical
wak
evo
rtex
shee
t
W2
V1
w r - 2Viq
V2
Blade section Looking outboardBlade at 3 o’clock
Chord line
Viq
Vix
Vi
Prop/turbine flowfield is complex. Numerically integrate wake-induced velocities and apply the boundary conditions to solve for blade loading
b
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Speed Ratio, s ≡ v / ( w R tan bt) 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
B=2
2
B=8
8
Force Coef., F ≡ f/(qpR2)
Low-RPM 8 Blades bt = 30o
0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8
0.0
0.2
0.4
0.6
0.8
1.0
h
Speed Ratio, s ≡ v / ( w R tan bt)
Efficiency
Turbine t w / (f v)
Propeller f v / ( t w)
Pinwheel
Regeneration Max efficiency
Windprop Efficiency and Thrust
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
• Comparable efficiency by mode• Eight blades spin slow & quiet• Climb power ~ 7x cruise power
Two windprops, samethrust and diameter
High-RPM 2 Blades bt = 14o
2
8
Propeller ~ cruise
Propeller ~ climb
Regen capacity
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Presentation Contents
Regenerative Electric-powered Flight J. Philip Barnes
The visionaries
Windprop
Motor-Generators
M-GiGBT
VM
Power Electronics
Regenosoar
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em
t
w
eb
N turns
Generating
i
Bi
Change to generator mode:Same direction of rotationSame sign of EMF Same ratio, EMF/speedSame ratio, torque/currentTorque & current reversed
em
t
w
eb
N turns
Motoring
B
iB
i
Motor-generator Principles
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
Motoring mode:Any motor is a generatorEMF proportional to RPMTorque propor. to current
tw = em iem= k w t = k i
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0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
Speed Ratio, kw/eb = EMF Ratio, em /eb
Non-dimensional Characterization of Permanent-magnet DC Motor-generator-battery System Performance ~ Theory and Test Data
Motor-generator & Battery: Efficiency Envelope and Test Data
REGENERATIONLMCLTD.net
MOTORINGEEMCO 427D100
CURRENT GROUP, i Rt / e
b
TORQUE GROUP, t Rt / (k e
b )
Phil
Barn
es A
pr-0
8-20
11
100% Duty Cycle
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
THEO. EFFICIENCY, kw/e b e
b /(kw)
Windprop synergy
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“Equivalent brushed” machine
BLDC M-G & inverter-rectifier: Equivalent-brushed machine
M-G & inverter/rectifier system has “brushed-DC” equivalent
M-Geb
i
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
Inverter-Rectifier
t
w
Brushless motor-gen: Electronically commutate 2 of 3 phases
kw
tw = em iem= k w t = k i
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Presentation Contents
Regenerative Electric-powered Flight J. Philip Barnes
The visionaries
Windprop
Brushless MGM-GiGBT
VM
Power Electronics
Brushed MG
Regenosoar
15
“Six-pack” inverter-rectifier ("inverting" for motoring)
• Inverter converts 2-wire DC to 3-wire "AC“• Alternating transistor “diagonal pairs”• Commutation toggles each phase 0-to-VB
• Relatively low frequency at full power
VB
VB
12
3
1
2
3-7V 15V S
N
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
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Six-pack inverter-rectifier (rectification for regeneration)
eB
12
3
• M-G max delta EMF exceeds battery EMF• Six-pack rectifies 3-wire AC into 2-wire DC• Battery recharged through flyback diodes• IGBTs unidirectional: commutation ignored
Snapshote1 - e3 > eB
1
2
3
Current to battery!
Diodes provide"free" regen!
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
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Cruise efficiency penalty when “chopping” the main current
• Typical PWM switching freq. f ≈ 20 kHz (inaudible)• Per-iGBT switching energy loss S ≈ 20 mJ per cycle • Chopping loss = f S = 0.4 kW ≈ 10% in loitering flight
DC boost converter eliminates part-power chopping loss
BLDC commutation voltage waveform (full power) has “relatively-low” frequency ion
iav| |
dt| t |
Commutation with chopping PWM superimposed (cruise)has “very-high” frequency
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
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DC boost converter - efficiency and regen application
"Evaluation of 2004 Toyota Prius,"Oakridge National Lab, U.S. Dept. of Energy
233 Vdc in
5 10 15 20 kW
Regen
M-G
Motor
PWMiGBT
CL VB
• DC boost converter efficiently integrates windprop & motor-gen• IGBT gate PWM duty cycle adjusts battery or M-G voltage boost• Efficient bi-directional power over the full operating range
Climb Regen
Cruise
97% power-conditioning efficiency for any mode
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
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“Chop” Vs. “boost” architectures compared
"Chopper" architecturePWM main current chop540V battery10% loss at loiterRegen: none or inefficient
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
M-G
i
t w
PWM superimposed on commutation
Inverter-Rectifier
540Vbatt.
"Boost" architecturePWM sets DCBC boost200V battery03% loss at loiterRegen capable & efficient
M-G
i
DC BoostConverter
2-way boost t w
PWM
Inverter-Rectifier
Commutation
200Vbatt.
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Presentation Contents
Regenerative Electric-powered Flight J. Philip Barnes
The visionaries
Windprop
Brushless MGM-GiGBT
VM
Power Electronics
Brushed MG
Regenosoar
Regenerative Electric-powered Flight J. Philip Barnes 21
Counter rotorsSymmetric flowZero net torque
8-blade rotorsLow RPM, quiet, Low tip Mach
Compact power trainBatt., M-G, ctrl, cables
Regenosoar, 1 of 2
Regenerative Electric-powered Flight J. Philip Barnes 22
Ground handlingNo assistance req'dWinglet tip wheels
Pusher Config.Laminar flow,No helix upset
Pod-air-cooled MG & PE
Regen parked in the windWith safety perimeter
Regenosoar, 2 of 2
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Steady-state climb or descent ~ New Formulation, New Insight
Glider, soaring bird, or "clean" regen• T/D = 0 (no thrust)• Sink rate (-dz/dt) = nn(D/L)V
With or without propulsion system• Sink increases with g-load (nn)• D/L also increases with (nn)
Regen operating mode T/D• climb 4.6 • cruise = 1.0 • pinwheel glide -0.1• efficient regen (thermal) -0.7 • capacity regen (descent) -2.0
L= nn W
T-Df
W
g
V
g
Therefore,Vdz/dtrate,climb3)
(T/D)(D/W)T/W2)D/Ln(L/W)(D/L)D/W1)
V(D/W)]V[(T/W)L/Wndefine V/W;bymultiply
state}{steadyWDT
n
n
γ
γ
γ
sin
sin
sin
Derive steady-climb Equation:
Note: nn= cos g /cos f*
cL = nn W/ (qS)
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
* SAE 2004-01-3088 EQN 5.2, dg/dt = 0
1][(T/D)V(D/L)ndz/dt n
“Total Sink”“TotalClimb”
WindpropEffect
“Clean” sink rateUpdraft
D
TV
L
Dnuz nt 11
“Physics” require: • Updraft (or descent)• High L/D, low sink• High system efficiency
• Regen “fallouts” incl.• Steep final descent• Landing thrust reversal• Ground wind recharge
Regenosoar: Physics and fallouts
Based on weather & geography,potential for “flight without fuel”
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0
0
0
0
1
0
0
0
000
2
00
0
0
0
3
4
Radius from Centerline, m0 100 200 300 400 5000100200300400500
Elevation, zo ~ m
0
500
1000
1500
2000
2500
3000
3500
4000
u, m/s
Thermal Updraft Contours
Total Energy = Kinetic + Potential
Total Energy = Kinetic + Potential + Stored
• 1oC warmer-air column• 20-minute lifetime• ~ solar power x 10
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
U ~ m/s
Elevation, zo ~ m
12
34
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Climb & regeneration in the Thermal – Climb rate
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
Optimum
Equilibrium Regeneration
Climb rate, m/s
27Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
Equilibrium Regeneration
Optimum
Climb & regeneration in the Thermal – Energy rate
Energy rate, m/s
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Regenosoar point performance
Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
Parameter ↓ Climb, max L/D
Cruise,
max cL0.5/cD
Pinwheel, max L/D
Regen ridge lift
Regen Thermal
Regen descent
Updraft, u ~ m/s 0.00 0.00 0.00 2.0 3.7 0.0
Rotor speed ratio, s ≡ V/ [w R tanbt] 0.57 0.85 1.00 1.15 1.75 1.75
Windprop (rotor) speed ~ RPM 1282 1138 731 841 380 553
Windprop efficiency (prop. or turb.) 0.63 0.84 0 0.85 0.64 0.64
DCBC voltage gain (Gb : Gm) 2.68 : 1 1.4 : 1 n/a 1 : 1.12 1 : 2.66 1 : 1.97
MG speed ratio, ne = Gm k w / (Gb b) 0.530 0.900 0 1.045 1.120 1.209
Motor-gen & control efficiency, he 0.51 0.84 0 0.73 0.84 0.79
Boosted EMF (Gbb : Gmm) Volts 537 : 284 280 : 252 n/a 200 : 209 200 : 224 200 : 242
System efficiency 0.32 0.70 0 0.62 0.54 0.50
Battery energy storage rate ~ kW -44.0 -7.1 0 2.1 1.6 4.6
Battery current (output), ib ~ Amps 220 35.3 0 -10.5 -7.9 -22.9
Vehicle total shaft power ~ kW 22.4 5.9 0 -2.9 -1.9 -5.8
Total climb ~ m/s -8.1 -1.6 -0.9 0.5 2.4 -2.3
29Regenerative Electric-powered Flight J. Philip Barnes www.HowFliesTheAlbatross.com
A "regen" is coming soon to an airport near you!
Conclusion – Regenerative Electric Flight
M-GiGBT
VM
Synergy
Integration
inv.rect