regen - HowFliesTheAlbatross.com

Report
Regenerative Electric Flight
Synergy and Integration
of Dual-role Machines
J. Philip Barnes AIAA 2015-1302
07 Jan 2015 original
23 Feb 2015 Update
1
Presentation Contents
Windprop
Regenosoar
The visionaries
Integration
Synergy
VM
iGBT
M-G
Brushless MG
Power Electronics
Brushed MG
Regenerative Electric-powered Flight J. Philip Barnes
2
Hermann Glauert
“Consider the case of a
windmill on an aeroplane”
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
3
Paul MacCready
Regenerative electric flight
concept “with caution,” ‘99
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
4
Presentation Contents
Windprop
Regenosoar
The visionaries
VM
iGBT
M-G
Brushless MG
Power Electronics
Brushed MG
Regenerative Electric-powered Flight J. Philip Barnes
5
Rotor velocity diagram - "Pinwheeling" & “Betz” conditions
wr
Blade section
Looking outboard,
Blade at 3 o’clock
Vo
Axial
wind
Vo
b
b
• Angle of attack = 0, hub-to-tip
• wr tanb = Vo Therefore:
• r tanb = Vo /w = R tan btip
• Approaches "Betz Condition“
Rotational
wind, w r
Vo
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
Windprop Blade Angle and Operational Mode
Propeller
b
L
Turbine
Pinwheel
b
b
V
V
V
wr
wr
wr
-L
W
W
W
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
7
Propeller blade - comprehensive velocity diagram
W2
Blade section
Looking outboard
Blade at 3 o’clock
w r - 2Viq
V1
Chord line
b
Axial
wind
V1  Vo+Vix
V2
Vix
Viq
Vi
•
•
•
•
•
•
•
•
•
•
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
f
z
Rotational wind
Wq  w r - Viq
a
V1
Relative
wind W1
J. Philip Barnes
Prop/turbine flowfield is complex.
Numerically integrate wake-induced
velocities and apply the boundary
conditions to solve for blade loading
www.HowFliesTheAlbatross.com
Windprop Efficiency and Thrust
1.0
Efficiency
8
0.8
2
0.6
h
Low-RPM 8 Blades bt = 30o
Propeller
f v / (t w)
0.4
Turbine
t w / (f v)
0.2
Speed Ratio, s ≡ v / (w R tan bt)
0.0
0.5
1.0
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
0.9
Propeller ~ climb
0.8
B=8
0.7
• Comparable efficiency by mode
• Eight blades spin slow & quiet
• Climb power ~ 7x cruise power
B=2
0.6
0.5
0.4
Propeller
~ cruise
0.3
0.2
0.1
Force Coef.,
F ≡ f/(qpR2)
Regeneration
Max efficiency
Regen
capacity
0.0
-0.1
Pinwheel
High-RPM 2 Blades bt = 14o
2
-0.2
8
-0.3
-0.4
0.5
Two windprops, same
thrust and diameter
Speed Ratio, s ≡ v / (w R tan bt)
0.6
0.7
0.8
0.9
1.0
1.1
Regenerative Electric-powered Flight
1.2
1.3
1.4
J. Philip Barnes
1.5
1.6
1.7
1.8
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9
Presentation Contents
Windprop
Regenosoar
The visionaries
MotorGenerators
VM
iGBT
M-G
Power Electronics
Regenerative Electric-powered Flight J. Philip Barnes
10
Motor-generator Principles
t
w
B
em
i
i
Change to generator mode:
Same direction of rotation
Same sign of EMF
Same ratio, EMF/speed
Same ratio, torque/current
Torque & current reversed
B
eb
Motoring
Motoring mode:
Any motor is a generator
EMF proportional to RPM
Torque propor. to current
Regenerative Electric-powered Flight
tw = em i
em= k w
t=ki
i
t
w
em
i
B
eb
Generating
J. Philip Barnes
www.HowFliesTheAlbatross.com
11
Motor-generator & Battery: Efficiency Envelope and Test Data
Non-dimensional Characterization of Permanent-magnet DC
Motor-generator-battery System Performance ~ Theory and Test Data
1.0
100% Duty Cycle
0.8
REGENERATION
MOTORING
0.6
LMCLTD.net
EEMCO 427D100
0.4
Windprop
synergy
0.2
Phil Barnes Apr-08-2011
0.0
-0.2
-0.4
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Speed Ratio, kw/eb = EMF Ratio, em /eb
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
12
BLDC M-G & inverter-rectifier: Equivalent-brushed machine
kw
i
InverterRectifier
eb
t
M-G
w
tw = em i
em= k w
t=ki
Brushless motor-gen: Electronically commutate 2 of 3 phases
M-G & inverter/rectifier system has “brushed-DC” equivalent
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
13
Presentation Contents
Windprop
Regenosoar
The visionaries
VM
iGBT
M-G
Brushless MG
Power Electronics
Brushed MG
Regenerative Electric-powered Flight J. Philip Barnes
14
“Six-pack” inverter-rectifier ("inverting" for motoring)
VB
1
2
2
-7V 15V
VB
•
•
•
•
1
3
3
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
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
15
Six-pack inverter-rectifier (rectification for regeneration)
Snapshot
e1 - e3 > eB
1
1
eB
Diodes provide
"free" regen!
2
2
3
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
Regenerative Electric-powered Flight
J. Philip Barnes
Current to battery!
www.HowFliesTheAlbatross.com
16
Cruise efficiency penalty when “chopping” the main current
BLDC commutation voltage
waveform (full power) has
“relatively-low” frequency
Commutation with chopping
PWM superimposed (cruise)
has “very-high” frequency
ion
iav
| t | | | dt
• 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
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
17
DC boost converter - efficiency and regen application
233 Vdc in
97% power-conditioning
efficiency for any mode
Cruise
Regen
Climb
Regen
5
Motor
VB
L
PWM
C
M-G
10
15
20 kW
"Evaluation of 2004 Toyota Prius,"
Oakridge National Lab, U.S. Dept. of Energy
iGBT
• 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
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
18
“Chop” Vs. “boost” architectures compared
PWM superimposed
on commutation
i
540V
batt.
"Chopper" architecture
PWM main current chop
540V battery
10% loss at loiter
Regen: none or inefficient
M-G
InverterRectifier
w
t
Commutation
i
"Boost" architecture
PWM sets DCBC boost
200V battery
03% loss at loiter
Regen capable & efficient
Regenerative Electric-powered Flight
200V
batt.
DC Boost
Converter
PWM
J. Philip Barnes
M-G
InverterRectifier
2-way
boost
www.HowFliesTheAlbatross.com
t
w
19
Presentation Contents
Windprop
Regenosoar
The visionaries
VM
iGBT
M-G
Brushless MG
Power Electronics
Brushed MG
Regenerative Electric-powered Flight J. Philip Barnes
20
Regenosoar, 1 of 2
8-blade rotors
Low RPM, quiet,
Low tip Mach
Counter rotors
Symmetric flow
Zero net torque
Compact power train
Batt., M-G, ctrl, cables
Regenerative Electric-powered Flight J. Philip Barnes
21
Regenosoar, 2 of 2
Pusher Config.
Laminar flow,
No helix upset
Regen parked in the wind
With safety perimeter
Ground handling
No assistance req'd
Winglet tip wheels
Pod-air-cooled MG & PE
Regenerative Electric-powered Flight J. Philip Barnes
22
Steady-state climb or descent ~ New Formulation, New Insight
Derive steady-climb Equation:
L= nn W
V
T  D  W sin γ {steady state}
multiply by V/W; define nn  L/W
g
V[(T/W)  (D/W)]  V sin γ
1) D/W  (L/W)(D/L)  nnD/L
2) T/W  (T/D)(D/W)
T-D
f
g
3) climb rate, dz/dt  V sin γ
Therefore,
W
dz/dt  nn (D/L) V [(T/D)  1]
Note: nn= cosg /cosf *
cL = nn W/ (qS)
* SAE 2004-01-3088 EQN 5.2, dg/dt = 0
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)
Regenerative Electric-powered Flight
J. Philip Barnes
Regen operating mode
• climb
• cruise
• pinwheel glide
• efficient regen (thermal)
• capacity regen (descent)
www.HowFliesTheAlbatross.com
T/D
 4.6
= 1.0
 -0.1
 -0.7
 -2.0
23
Regenosoar: Physics and fallouts
Based on weather & geography,
potential for “flight without fuel”
“Clean”
Updraft sink rate

zt  u  nn
“Total
Climb”
D
V
L
Windprop
Effect
T



1

e

1


D


“Total Sink”
“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
Thermal Updraft Contours
4000
E le v a tio n , z o ~ m
Elevation, zo ~ m
• 1oC warmer-air column
• 20-minute lifetime
• ~ solar power x 10
3500
0
0
0
0
u , m /s
U ~ m/s
3000
2500
2000
1
1
2
1500
2
0
3
3
1000
500
4
4
Total Energy
= Kinetic
+ Potential
Total Energy
= Kinetic
+ Potential
+ Stored
0
0
0
0
0
0
0
0
0
0
500
0
400
300
200
100
0
100
200
300
400
500
R a d iu s fro m C e n te rlin e , m
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
25
Climb & regeneration in the Thermal – Climb rate
Climb rate, m/s
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
26
Climb & regeneration in the Thermal – Energy rate
Energy rate, m/s
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
27
Regenosoar point performance
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 tanb t]
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
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 eb)
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 (Gbeb : Gmem) 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), i b ~ 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
Parameter ↓
DCBC voltage gain (Gb : Gm)
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
28
Conclusion – Regenerative Electric Flight
VM
iGBT
M-G
Integration
inv.
rect
A "regen" is coming soon
to an airport near you!
Synergy
Regenerative Electric-powered Flight
J. Philip Barnes
www.HowFliesTheAlbatross.com
29

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