New Type of Linear Switched Reluctance Generator for Wave

New Type of Linear Switched Reluctance Generator for Wave Energy Applications

L. García-Tabarés, M. Lafoz, M. Blanco, J. Torres, D. Obradors, J. Nájera, G. Navarro,

CIEMAT

F. García, A. Sánchez

WEDGE GLOBAL

GOBIERNO

DE ESPAÑA

MINISTERIO

DE CIENCIA, INNOVACIÓN

Y UNIVERSIDADESCentro de Investigaciones

Energéticas, Medioambientales

y Tecnológicas

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 764014

The World of Wave Energy Converters

UNDIGEN

Wedge Global (ES)

Point Absorber

Attenuator


The Heaving Point Absorber (HPA) Type WEC

FLOAT(Body 1)

SPAR +

INERTIA TANK(Body 2)

POWER TAKE-OFF (PTO)

OSCILLATING WATERSURFACE

In a HPA the energy is produced from the relative displacementbetween the two bodies in the Power Take-Off. A Point Absorberhas a small dimension compared to wave length and is able toharvest energy from any wave direction.

The W1 WEDGE Point Absorber


The Physics of Point Absorbers

FLOAT BODY 1

SPAR + INERTIA TANK

BODY 2

POWER TAKE-OFF

H(t)

OSCILLATING WATER SURFACE

BODY 1 WAVE EXCITATION FORCE & BOUYANCY

BODY 1 RADIATION FORCE: Damping

BODY 2 WAVE EXCITATION FORCE & BOUYANCY

BODY 2 RADIATION FORCE: Damping

PTO FORCE: To be converted into electrical power

BODY 1 TOTAL MASS

BODY 2 TOTAL MASS

GROUND

GROUND

Fw 0 FPTO a

Zj

v1RPTO 0

Force induced by the wave

Force produced

by the PTO

A Point Absorber is an oscillating system with acorresponding mechanical model, which can also beexpressed in terms of the equivalent electric circuit. Thecircuit allows an easy determination of the required force atthe PTO to extract the maximum energy from the wave.


GOALS: - Development of a new type of PTO based on SRM• Force Density x 2• IPCR x2• FtWE up to 80%• Capex/kW down by 25%• LCoE down by 30%

- Modularity & Crosscuting up to 500 kN & 3m/s- 3rd Generation of superconducting PTOs- Bussines models based on “open hardware models”

Participant Organization name Type Country

1 (C) Wedge Global S.L. WEC Developer Spain2 CIEMAT Pubilc R&D Center Spain3 WavEC - Offshore Renewables R6D Center Portugal4 CorPower Ocean WEC Developer Sweden5 Centipod LTD WEC Developer UK6 Hydrocap Energy SAS WEC Developer France7 OCEM Energy Technology srl Power Electronics Italy8 Columbus Superconductors (AGS) Superconductors Italy9 Engie Fabricom Installation & Services Belgium10 EDP Center New Energy Technologies R&D Center Portugal11 Asociación Española de Normalización Regulatory Body Spain

CENTIPOD LTD.

The SEA TITAN Project


The Principles of the Switched Reluctance Machines

ACTIVE SIDE

PASSIVE SIDE

THE CONCEPT OF THE MULTITRANSLATOR RECTANGULAR SWITCHED RELUCTANCE MACHINE

AC

TIV

ES

IDE

PA

SS

IVE

SID

EThe CYLINDRICAL SINGLE-SIDED SRM

A

B

C

-A-B-C

AC

TIV

E

SID

E

PA

SS

IVE

S

IDE


The Azimuthal SRM

PASSIVE SIDE

ACTIVE SIDE

The AZIMUTHAL SRM (Detail of One Phase)

AC

TIV

E S

IDE

PA

SS

IVE

SID

E

The AZIMUTHAL SRM(3-Phase Arrangement)


Configurations for the Azimuthal SRM

Pas

sive

Fix

ed

Act

ive

Mo

vin

g

Pas

sive

Fix

ed

Act

ive

Mo

vin

g

Act

ive

Mo

vin

g

Pas

sive

Fix

ed

Pas

sive

Fix

ed

Act

ive

Mo

vin

g

Pas

sive

Mo

vin

g

Act

ive

Fix

ed

Act

ive

Fix

ed

Pas

sive

Mo

vin

g

Pas

sive

Mo

vin

g

Act

ive

Fix

ed

Act

ive

Fix

ed

Pas

sive

Mo

vin

g

s/2

l

e

d

LONG SIDE MOVING

ms/2

s

s

l

e

d

SHORT SIDE MOVING

m


First Magnetic Calculations of the Azimuthal SRM

F

-F2D Model 1D Model

Coils Aspect Ratio has a great importance in the Force vs Position Curve

0

5000

10000

15000

20000

25000

30000

35000

40000

0 20 40 60 80 100 120 140 160 180

Force(N)

RelativePosition(mm)

QFModel

1DModel

QFAverage

0

2

4

6

8

10

12

14

16

18

20

0

5000

10000

15000

20000

25000

30000

35000

40000

0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9

Losses(k

W)

Force(N)

InnerDiameter(m)

FB2.0T

FB2.1T

PB2.0T

FP2.1T

Forcefor2.1T

Forcefor2.0T

Lossesfor2.1T

Lossesfor2.0T

Machine Size Optimization

0

2000

4000

6000

8000

10000

12000

14000

16000

0 20 40 60Force(N/n)

Posiition(mm)

1.8T

2.0T

2.1T

-2000

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0 50 100 150

Force(N/m

)

Position(m)

1.8T

2.0T

2.1T

(mm)


3-D Magnetic Calculations for the Azimuthal SRM

α

-5000

0

5000

10000

15000

20000

25000

30000

35000

40000

0 20 40 60 80 100 120 140 160 180

Force(N)

Displacement(mm)

α=0Maxwell

α=15Maxwell

α=22.5Maxwell

α=0Opera

α=15Opera

a=22.5Opera

QF

1D

0.79%

0.77%

0.72% 0.70%

0.68%

0.61%0.83% Force calculations using 3Dcodes have also beenperformed. The forceevolution is very sensitiveto the wedge angle of thepoles.


Current waveforms to design powerelectronics and power losses.

Flux & ForceTables

Postprocessing

Matlab-Simulink Model

SRM Model

Complete Simulation of the Azimuthal SRM

280 147

133

266

80 892,0

500 R220 R

67

Conceptual Design

FEM Modeling

Conceptual & FEM Design

&


COMPLETE AMSRM PROTOTYPE MACHINE

ACTIVE SIDE

PASSIVE SIDE

The Azimuthal SRM Prototype Overall DesignACTIVE

SIDE COILS

PASSIVESIDE RINGS

CONNECTING FLANGES BETWEEN RINGS

ROLLING GUIDES


The Azimuthal SRM Additional Calculations

133 147

90

1,5

60

257

271

32

DC Joule Losses AC Losses Iron Losses

TH

ER

MA

L C

ALC

ULA

TIO

NS

++

ME

CH

AN

ICA

L C

ALC

ULA

TIO

NS

Gap Misalignment

Stresses on the Passive Side Stresses on the Active Side


Testing the Azimuthal SRM

ACTIVESIDE 2(Generator)

ACTIVESIDE 1(Motor)

The PTO will be tested in a Back to Back configuration in which one of the machines acts as a generator and the other as a motor, both driven by an independent converter.


Towards a Superconducting Azimuthal SRM

Rext Rint

A superconducting version of an AMSRM is theoretically attractive because:

• The machine has only one side with coils and this side can be stationary.• Increasing the field from 2.1T to only 2.3 T and the current density from 5

Amm-2 to 30 Amm-2 would mean increasing the force by a factor of 8.• MgB2 can be an ideal candidate for the required levels of J & B, ......... BUT:

AC losses can be inadmissible high and this requires special wireconfiguration and different operation of the machine (Single-Pulse and notMulti-Pulse).

-50000

0

50000

100000

150000

200000

250000

300000

0 10 20 30 40 50 60

Force(N)

J(A/mm2)

ForcevsCurrentDensityfordifferentFieldValues

F2,1T

F2,3T

F2,5T

Force decreases due to the worst coil aspect ratio

Fundamental Period

≈0,067 s <>15Hz

Switching Period ≈ 0,0067s÷0,001s <>150Hz÷1kHz


• Heaving Point Absorbers are consolidated candidates for WECs

• Their capability to harvest energy is increased by hosting high force PTOs

• PTOs must produce a “vector” force (controllable in magnitude & phase)

• In April 2018 started the Sea Titan Project to develop a new concept of PTO based on a linear Switched Reluctance Machine.

• This PTO is based on an Azimuthal configuration that saves iron and has a better adaptation to the WEC geometry.

• The main deliverable of the Project is a 70 kN, 3ms-1 prototype to be tested horizontally at CIEMAT premises.

• This prototype has been magnetically, mechanically and thermally calculated and its design is practically finished.

• Additionally, Sea Titan considers the conceptual design of a superconducting version based on Mg B2 .

Summary & Conclusions

THANK YOU VERY MUCH !!!!!

Documents

New Type of Linear Switched Reluctance Generator for Wave