Permanent Magnet Generators For Wind Power

[Institute Name]

CONTENTS

1.INTRODUCTION4

1.1Electromechanical conversion in wind turbines4

1.2Advantages and disadvantages of direct-drive electromechanical conversion6

1.3Problem definition9

1.4Overview of this thesis10

1.5Comparison of Direct-Drive and Geared Generator Concepts for Wind Turbines11

2.Basic Machine Principles14

2.1Overview of PM Machine Types14

2.2Advantages of PM machines versus wound rotors and switched reluctance machines.14

2.2.1Synchronous machine vs. induction machine15

2.2.2Synchronous machine vs. switched reluctance machine15

2.2.3Synchronous machine: PM excitation vs electrical excitation16

2.3Description of existing PM machine topologies21

2.3.1Air gap orientation: Radial (R) or axial (A)22

2.3.2Stator core orientation: longitudinal (L) or transverse (T)23

2.3.3PM orientation with respect to air gap: surface-mounted (SM) or flux concentrating (FC)24

2.3.4Copper housing: slotted (S) or slotless (SL)25

2.4PM machines considered for further investigation25

2.4.1Conventional PM synchronous machine25

2.4.2Conventional PM synchronous machine with flux concentration26

2.4.3Slotted axial-flux PM machine27

2.4.4TORUS29

2.4.5Surface-mounted transverse-flux PM machine29

2.4.6Flux-concentrating transverse-flux PM machine31

3.Wind power32

3.1General32

3.2Basic principle33

3.3Power and efficiency rates35

3.4Basic comparison with conventional electricity production and benefits of wind power37

3.5Costs of wind energy38

3.6Wind turbine power control39

3.7Stall controlled rotors39

3.8Variable speed rotors40

3.9Trends40

3.9.1Turbines have grown larger and taller40

3.9.2Investment costs have decreased41

3.9.3Turbine efficiency has increased41

3.10Wind turbine technology42

3.10.1Technology42

3.10.2Rotor and blades42

3.10.3Nacelle43

3.10.4Gearbox43

3.10.5Braking system43

3.10.6Control system43

4.gearbox44

4.1background44

4.2problems associated with gearboxes44

4.3Observations on the Basic Problems45

4.4Gearbox advantages46

4.5Gearbox disadvantages50

5.Wind Turbine, Gearbox and PMG configurations52

5.1Configurations52

5.2Units in MathCAD53

5.3Wind Turbine configuration54

5.4GEARBOX configuration55

5.5Permanent Magnet Generator configuration56

6.Converters, Transformer and Cables configuration58

6.1Medium Voltage Converter Cable configuration58

6.2LV Generator - Converter Cable configuration61

6.3Medium Voltage Converter configuration64

6.4LV Converter configuration66

6.5MV Converter - Transformer Cable configuration67

6.6LV Generator - Transformer Cable configuration69

6.7TRANSFORMER configuration72

7.RESULTS74

7.1Direct Drive Permanent Magnet Generator + Medium Voltage Converter Results76

7.2Direct Drive Permanent Magnet Generator + Low Voltage Converter Results77

7.3Geared Permanent Magnet Generator + 6 Low Voltage Converter Results78

7.4Results summery79

8.CONCLUSION81

APPENDIX A-BIBLIOGRAPHY88

appendix B-FUTURE WORK92

APPENDIX C: Further Wind Power Overview95

 INTRODUCTION

Electromechanical Conversion in Wind turbines

Wind power is an expanding percentage of the power provided to the public electrical power network. An mean yearly development rate of 31% in the established Wind power capability has been discerned over the last couple of years [1]. To a certain span, this powerful development rate is assisted by the ecological principles and levy inducements of the diverse nationwide governments. However, another working out component has been the declining output cost of Wind power [2]. Wind power is now nearly comparable with other more customary causes of electric power like coal, gas and atomic lifetime [3]. Technology development is absolutely one of the key components in producing Wind power more cost productive and reliable.

Wind turbines can be made with either constant-speed or variable-speed mechanical input. One of the localities where technological improvement have performed a foremost function in the last years is the development of innovative variable-speed Wind turbines. The variable-speed Wind turbine has some benefits, like higher power extraction from the Wind [4], smaller disturbance at reduced Wind pace and cleaner power move to the grid [5]. For these causes, the variable-speed Wind turbine is taking an expanding share of the market nowadays. Variable-speed can be accomplished in some ways. However, two configurations of variable-speed electromechanical converters are nowadays keeping attention: the direct-drive synchronous generator with power electrical devices converter and the doubly-fed induction generator with gearbox.

The  wind  power lifetime has been evolved very rapidly in the past couple of years. With the increasing penetration ...