1 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

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

2

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”

4

Paul MacCready


Regenerative electric flightconcept “with caution,” ‘99

5



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


7

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


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

9

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


• 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

10



The visionaries

Windprop

Motor-Generators

M-GiGBT

VM

Power Electronics

Regenosoar

11

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


Motoring mode:Any motor is a generatorEMF proportional to RPMTorque propor. to current

tw = em iem= k w t = k i

12

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


THEO. EFFICIENCY, kw/e b e

b /(kw)

Windprop synergy

13

“Equivalent brushed” machine

BLDC M-G & inverter-rectifier: Equivalent-brushed machine

M-G & inverter/rectifier system has “brushed-DC” equivalent

M-Geb

i


Inverter-Rectifier

t

w

Brushless motor-gen: Electronically commutate 2 of 3 phases

kw

tw = em iem= k w t = k i

14



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


16

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!


17

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


18

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


19

“Chop” Vs. “boost” architectures compared

"Chopper" architecturePWM main current chop540V battery10% loss at loiterRegen: none or inefficient


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.

20



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

23

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)


* 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”

25

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


U ~ m/s

Elevation, zo ~ m

12

34

26

Climb & regeneration in the Thermal – Climb rate


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

28

Regenosoar point performance


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

1 Regenerative Electric Flight Synergy and Integration of Dual-role Machines J. Philip Barnes AIAA 2015-1302 07 Jan 2015 original 23 Feb 2015 Update.

Documents

w propeller v r

absolute velocity v

tip r tan

oclock chord line v

r tan tip similar

r relative wind w

f fq r

blade wake