Dr. Longya Xu

The Ohio State University

Dec., 2008

1. Introduction

� Major Wind Power System Configurations

� Challenges to Remain in Power Grid

� HVDC - Promising in Wind Power

2. What and Why DEBRM2. What and Why DEBRM

� System Configuration

� Features of Magnetic Structure

� DEBRM in Wind Power Generation

3. Conclusions

MW

New Installation

Cumulative Inst.

MW

2q Stator windings2p Stator windings GearsGears

Bi-Directional Inverters

Dual Stator Windings

No windings, No Slip Rings and Brushes, No Magnets on Rotor!!

Segmental Reluctance Rotor

[ ] [ ] [ ][ ]{ }

[ ] [ ] [ ] [ ] [ ]

[ ] [ ] [ ] [ ] [ ]r

r

dV i r L i

dt

d di r L i L i

dt dt

d di r L i L i

d dtω

θ

= +

= + +

= + +

α

θ

Sample 2-Phase

AC Machine

[ ]

0 0 sin cos

0 0 cos sin

sin cos 0 0

cos sin 0 0

sr r sr r

sr r sr r

r

sr r sr r

sr r sr r

K K

K KL

K K

K K

θ θθ θ

θθ θθ θ

− − − ∂ = +

∂ − − −

�

�

� � � �

�

�

rd dtθ α

β

θr

� All windings - magnetically coupled

� Lmutual - rotor position dependent

� Speed (motion induced) voltage exists

[ ] [ ]speed r

r

dV L i

dω

θ

=

� Electromagnetic torque

Electromechanical power

[ ] [ ] [ ]0 1

2

Tce

r r

LWT i i

θ θ∂∂

= =∂ ∂

EM m eP Tω=

2x 10

-4 2p=2 airgap flux

0 1 2 3 4 5 6 7-2

-1

0

1

Rotor angle

0 1 2 3 4 5 6 7-2

-1

0

1

2x 10

-4 2p=2 airgap flux

Rotor angle

0 1 2 3 4 5 6-2

-1.5

-1

-0.5

0

0.5

1

1.5

2x 10

-4 2p=2 airgap flux

0.02

0.04

0.062p=2 excited 2p=4 mutual inductance lAa-red lAb-blue lAc-green

Air gap Flux

Variation With

Rotor Rotating

Mutual

Inductance (Flux

0 50 100 150 200 250 300 350-0.06

-0.04

-0.02

0

0 50 100 150 200 250 300 350-0.06

-0.04

-0.02

0

0.02

0.04

0.06

Rotor angle

2p=2 excited 2p=6 mutual inductance lAa-red lAb-blue lAc-green

Inductance (Flux

Linkage)

Variation

Mutual

Inductance (Flux

Linkage)

Variation

p + q = prWith the above equation , the rotor speed

nr of the machine will be determined bynr of the machine will be determined by

60 ( )p q

r

f fn

p q

±=

+

Can Be Made Very Low Speed without Severe Size Penalty!!

Design Requirements:Design Requirements:Design Requirements:Design Requirements:Design Requirements:Design Requirements:Design Requirements:Design Requirements:

DirectDirectDirectDirectDirectDirectDirectDirect--------Driven:Driven:Driven:Driven:Driven:Driven:Driven:Driven: No gear boxNo gear boxNo gear boxNo gear boxNo gear boxNo gear boxNo gear boxNo gear box

Power Rating: Power Rating: Power Rating: Power Rating: Power Rating: Power Rating: Power Rating: Power Rating: 2,000,000w2,000,000w2,000,000w2,000,000w2,000,000w2,000,000w2,000,000w2,000,000wPower Rating: Power Rating: Power Rating: Power Rating: Power Rating: Power Rating: Power Rating: Power Rating: 2,000,000w2,000,000w2,000,000w2,000,000w2,000,000w2,000,000w2,000,000w2,000,000w

SpeedSpeedSpeedSpeedSpeedSpeedSpeedSpeed RangeRangeRangeRangeRangeRangeRangeRange: : : : : : : : 1010101010101010--------30rpm30rpm30rpm30rpm30rpm30rpm30rpm30rpm

Max. Torque: Max. Torque: Max. Torque: Max. Torque: Max. Torque: Max. Torque: Max. Torque: Max. Torque: 750,000 Nm750,000 Nm750,000 Nm750,000 Nm750,000 Nm750,000 Nm750,000 Nm750,000 Nm

Voltage:Voltage:Voltage:Voltage:Voltage:Voltage:Voltage:Voltage: 690 volts690 volts690 volts690 volts690 volts690 volts690 volts690 volts

Current: Current: Current: Current: Current: Current: Current: Current: 1,700 amps1,700 amps1,700 amps1,700 amps1,700 amps1,700 amps1,700 amps1,700 amps

Rotating PartStationary Part

Rotor Pole Number：2pr=240

Dual Stator Pole Numbers：2p=60 2q=180

Stator OD：3698.4mm Stator ID：3200mm

Rotor OD：3850mm Rotor ID：3700mmRotor OD：3850mm Rotor ID：3700mm

Effective L：1300mm

Estimated Weight of Copper：7.3T

Estimated Weight of iron ：25T

Estimated Weight of Total ：35T

-100.00

0.00

100.00

200.00

Y1 [Wb]

Ansoft Corporation Maxwell2DDesign1XY Plot 4

Curve Info

FluxLinkage(Winding2A)

Setup1 : Transient

FluxLinkage(Winding2B)

Setup1 : Transient

FluxLinkage(Winding2C)

Setup1 : Transient

0.00 50.00 100.00 150.00 200.00Time [ms]

-100.00

-50.00

0.00

50.00

100.00

Y1 [Wb]

Ansoft Corporation Maxwell2DDesign1XY Plot 5

Curve Info

FluxLinkage(Winding6A)

Setup1 : Transient

FluxLinkage(Winding6B)

Setup1 : Transient

FluxLinkage(Winding6C)

Setup1 : Transient

10.00 20.00 30.00 40.00 50.00Time [ms]

-200.00

转矩-功角曲线

200

400

600

800

1000

kNm）

Torque-Power Angle

-1000

-800

-600

-400

-200

0

200

0 100 200 300 400 500

功率角（°）

转矩（kNm

Power Angle

Torque

Machine

Performance

Doubly Fed IMG Direct-Driven PMG DEBRM Generator

Gear Box Required No No/Flexible

Size and Weight Small Very Big Big/Small

Inverter Capacity 30% 100% 100-30%

Brushes -Slip Rings Required No No

Permanent Magnets No Required No

Control Complexity Complex Less Complex Complex

Manufacturing Conventional Conventional Rotor-New

HVDC Compatibility No Yes Yes

Costs Less Heavy Less

• Wind power technologies are growing in fast-pace. Advanced wind

power generation system demands new technologies to enhance

system reliability and reduce costs;

• DEBRM has no windings, no brushes and slip rings on the rotor，with a rugged structure、and easy maintenance, showing high

potentials;

• It is possible to build doubly excited, directly driven wind power • It is possible to build doubly excited, directly driven wind power

generating system using DEBRM. Compared to PM direct-driven

systems, DEBRM direct-driven system needs no permanent magnets

and has a controllable field;

• Operated in the doubly excited mode, the capacity of the inverter in

DEBRM wind system is only a fraction of the total system capacity;

• DEBRM based wind power generation system is suitable for HVDC

power transmission for off-shore wind farm.