“EcoSwing has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 656024.”

“Herein we reflect only the author's view. The Commission is not responsible for any use that may be made of the information it contains.”

Results of Ground-Based TestsD.8.3 – Public results of ground based tests at Fraunhofer IWESRecapped by Hans Kyling, Fraunhofer IWES

2

Fraunhofer IWES DyNaLab

Load

Application

System

Grid Simulation

DriveGantry Crane Key features:

Drive5° inclined drive train

10/15 MW (nominal/peak) - Twin Synchronous Direct Drive

8.6/13 MNm (nominal/peak)

Flexible coupling

Hydraulic safety coupling (adjustable 8-15 MNm)

Hydraulic load application systemThrust: ± 1900 kN, Radial : ± 2000 kN

Bending: ± 20000 kNm (rotating y-, z-axis)

Dynamic: 0-2 Hz (30% of max. load)

0-g unit for weight compensation (150 to)

Grid simulation10/20/36 kV tappings

44 MVA installed converter capacity

LVRT & HVRT simulation.

• Integration planning of specimen to existing test bench• Cooling• Mechanical adaption• Electrical• Communication specimen <-> test bench• DAQ

• Development of a detailed test plan• Align test requirements with all partners• Needed sensors

• Development of a detailed schedule for the test campaign• Test bench time slot not freely moveable• Clear responsibilities for tasks (nine parties have to coordinate their efforts).

3

Ground test site preparation

Ecoswing test setup

4

Test bench

CoolingDUT

DUT

Transformer

Converter

Rotor adaption

Cooling system, cryo compressors

5

The generator stator and rotor need to be integrated into the DyNaLab cooling system:

Generator requirements:

Stator HX Rotor Compressor

Cooling power [kW]250 + x at rated operation

8 kW per compressor

Water flow [l/min] 635 l/m 9 l/min per compressor)

Water Tin max [°C] < 35 °C < 35 °C

Water Tout max. [°C] 46 °C Tbd

Cooling liquid Water/Glycol Water/Glycol

Cooling mixture 60:40 60:40

Rated pressure drop [bar] 0.5 bar 0.5 bar

• Cooling down period faster then calculated 14 days compared to 18 days

• Good thermal design

• Cooling power of cold heads higher than anticipated

• Overall temperature level was lower then anticipated:

• Thermal design was estimated very conservative

• Cryostat vacuum better then expected

• 2.7∙10-10 bar and self-sustaining

• No pump required during operation

8/27/2019Confidential and Proprietary 6

Cryogenics performance

Lifting

Period

Faster then

computed

Lower then

computed

Aligned test plan

Model validation

Functionaltests

9 partners(expertises,

points ofview)

7

Test plan development

8

Test SpecificationsExample: Efficiency test

9

Mechanical AdaptionTower Adaption

10

Mechanical AdaptionRotor Adaption

Max. desired test load Max. tolerable short time load

Fx (kN) 0 0 (axially free support)

Fy (kN) 0 3,000

Fz (kN) 0 3,000

Mx (kNm) +3,000 / -0 +3,600 /-0

My (kNm) 0 3,800

Mz (kNm) 0 3,800

Table 1: Design Loads for Tower Head Adaptation.

11

Verification on Kinematics of Rotor Adaption – FEM based

Pure driving torque of 3 MNm was applied and resulting torque on driven side added up to 2964 kNm

12

Verification on Kinematics of Rotor Adaption – MBS based

Ramping up speed and torque Ramping up speed and torqueand additional constant shear force

-> Simulation confirms expected behaviour of rotor adaption.

Inneraxial forceson loadcell(s)

• Measurement of input torque next to generator main shaft flange

• Force lever system

• Symmetrical arrangement

• 3 calibrated load cells.

13

Torque measurement system

Verification on compression test bench Verification for tension rod assembly

Validation measurements on load cells

14

Bolt connection through load cell

Tension loading with reference load cell

Clamping factor was experimentally determined for each tension rod.

By measuring the compression load on the cell the rod tension can be determined.

15

Assembly at IWESHall, EcoSwing generator

16

Assembly at IWESLifting, Installation at DyNaLab

✓First excitation up to 40 A

✓Switch to rotary helium supply

✓First excitation up to 285 A

✓First rotation

✓Converter tuning

✓Short circuit test

✓Short circuit and No-Load test

× Quench of one HTS coil

✓First grid connection

✓1 MW power to grid for approx. 1 h with defective coil (120 A rotor current 470 A design current)

17

Conducted tests / occured events

8/27/2019

Some detail findingsPermanent short circuit test

0

100

200

300

400

500

600

700

800

0 20 40 60 80 100 120

Stat

or

curr

ent

(Arm

s)

rotor current (A)

Short Circuit test at 15rpm

Isc = 121 A

8/27/2019

Some detail findingsPermanent short circuit test

No signs of unexpected heating in stator or in bearings

• Stator voltage reached nominal at 260 A rotor current

• The no-load curve does not show any unexpected behavior and is better than the calculated one.

• The reason for this is MAYBE better behavior of stator core when high saturated.

8/27/2019 20

Some detail findingsNo load tests

8/27/2019

Some detail findings Harmonics

0.00000%

0.02000%

0.04000%

0.06000%

0.08000%

0.10000%

0.12000%

0.14000%

0.16000%

0.18000%

3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95

VOLTAGE HARMONICS at 71V

0.00000%

0.20000%

0.40000%

0.60000%

0.80000%

1.00000%

1.20000%

1.40000%

1.60000%

1.80000%

3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95

VOLTAGE HARMONICS at 690V

• At 10% of Un extremely low harmonics

• 0.16% (H5)

• Reason is the large mechanical airgap, allowed by superconducting technology

• At 100% Un still very low harmonics• 1.6% (H11 grows because of saturation)• Reason for this is MAYBE the extremely

large airgap – which is unique for HTS machines – therefore this is ONLY possible with HTS machine.

• During the test we experienced a quench

• A quench is the transition from superconducting to non-superconducting

• This can be damaging when localized on one hot spot

• In our case this was localized to one of the rotor coils

• There are several possible reasons for this quench like an undetected defect of the superconducting tape or a damage of the coil during mounting

• A detailed investigation is planned

• To avoid further damage we proceeded with partial rotor excitation.

8/27/2019 22

Some detail findingsQuench

8/27/2019 23

Some detail findings Partial power test

0

50000

100000

150000

200000

250000

300000

0 100 200 300 400 500 600

Out

put P

ower

Stator Current Iq

EcoSwing: Power of 1 Converter (of 4)

P (1/4 Converter), 14.5 rpm [W]

Commissioning with converter successful and reached 1 MW

Commutation angle found, dq axis decoupled.

8/27/2019 24

Partial power testRotor adaption load cells unfiltered

The operational loads

measured on the

rods of the rotor

adaption seem to

have a noisy signal,

but…

8/27/2019 25

Partial power testRotor adaption load cells transient unfiltered

For the three

rods average

operational

loads

of 325, 306.5

bzw. 336 kN

are measured.

Additionally there are

amplitudes of 32, 28.5

bzw. 27 kN oscillating

with the rotation

frequency.

8/27/2019 26

Partial power testRotor adaption load cells transient unfilteredOperational Loads in Rod Direction

For the three

rods average

operational

loads

of 325, 306.5

bzw. 336 kN

are measured.

Additionally there are

amplitudes of 32, 28.5

bzw. 27 kN oscillating

with the rotation

frequency.

8/27/2019 27

Partial power testRotor adaption load cells transient unfilteredOperational Loads in Rod Direction

The resulting load

of all load cells

should be 0 in case

of pure torque

transmission.

The resuling forces of

all three load cells

are plotted for a

rotating coordinate

system.in x and y

direction. The raw

data as well as low

pass filtered signal is

given

The resulting shear

force consists of a

two parts:

1) 13.5 kN constant

shear force due

to eccentricity

2) ~27 kN periodic

shear force due

to mass of

adaption

8/27/2019 28

Partial power test: Power measurementsalong drivetrain and its naming

• The power was evaluated at 4 positions along the drivetrain.

• Pos. 1 & 4 based on electrical power measurements

• Pos. 2 & 3 based on strain gauge measurements using the rotational speed to calculate the acting power

8/27/2019 29

Partial power testPower comparison – low pass filtered

Remark:

Drop outs in power

signal on junction box

are due to an error in

the measurement

system

8/27/2019 30

Partial power test Major losses along drivetrain

Test bench

losses

Specimen

losses

8/27/2019 31

Partial power testPower comparison – low pass filtered

Comparing two different

working points one can see

that the mechanical

measurements do not scale

linearly to the electrical

ones.

The measurements

are not linear to each

other for different

power ranges.

Remark:

Drop outs in power

signal on junction box

are due to an error in

the measurement

system

8/27/2019 32

Partial power testPower comparison stable operation – low pass

It is not plausible that the

highest power is

measured for the load cell

position, but the deviation

is within the given

uncertainties.

Power deviations

from power input

at driving engine

in kW

Power deviations

from power input

at driving engine

in %

• Positioning of the sensors • Image of positions 1 & 8 as installed

33

First evaluation of acceleration measurements on stator

• Ramping up to 13 rpm

Two speeds led to a small excitement

• Colormap during power production

Three eigenfrequencies could be identifed.

34

First evaluation of acceleration measurements on stator

600.000.00 Hz

30.00

0.00

s

Tim

e

0.02

0.00

Am

plit

ude (

Peak)

g

489.8229.43

5.96

AutoPow er Gen_Stator_BackPlate:P1:+X WF 61 [0-30 s]

32.000.00 s

Time (Throughput)

13.00

0.00

Am

plit

ude

rpm

1.00

0.00

Am

plit

ude

0.76

0.00

Am

plit

ude

g4.94 10.46

2.52

4.98

F 1002:PECMC.RotSpeed

B2 1019:Gen_Stator_BackPlate:P1:+X only reduced values available

B2 1020:Gen_Stator_BackPlate:P1:+Y only reduced values available

B2 1021:Gen_Stator_BackPlate:P1:+Z only reduced values available

Superconductivity has matured sufficiently that we can follow an ambitious plan:

• Design, develop and manufacture a full scale multi-megawatt direct-drive superconducting wind generator

• Execute ground-based testing in Fraunhofer IWES’ DyNaLab

• Install and operate this superconducting drive train on an existing modern wind turbine in Thyborøn, Denmark(3 MW Class, 14 rpm, 128 m rotor)

• Prove that a superconducting drive train is cost-competitive.

The consortium and its plan

✓

✓