ELECTRO-MECHANICAL INTERACTION IN GAS TURBINE-GENERATOR SYSTEMS FOR MORE-ELECTRIC AIRCRAFT A thesis submitted to the University of Manchester for the degree of Doctor of Philosophy in the Faculty of Engineering and Physical Sciences 2012 THOMAS FEEHALLY SCHOOL OF ELECTRICAL AND ELECTRONIC ENGINEERING Table of Figures ......................................................................................................... 10 Abstract ...................................................................................................................... 15 Declaration ................................................................................................................. 16 Copyright statement .................................................................................................. 16 Acknowledgement ..................................................................................................... 17 Table of Abbreviations ............................................................................................. 18 Table of Notation ....................................................................................................... 20 Chapter 1 Introduction .............................................................................................. 22 1.1 Background .......................................................................................................... 22 1.1.1 Environmental Considerations ....................................................................... 22 1.1.1.1 Aviation and Climate Change .......................................................................................... 22 1.1.2 Aircraft operating costs .................................................................................. 23 1.1.3 Reducing fuel burn and maintenance requirements ....................................... 24 1.2 Aims and Objectives of research ....................................................................... 25 1.3 Significant contribution ...................................................................................... 26 1.4 Overview of thesis ............................................................................................... 26 Chapter 2 Literature review ..................................................................................... 29 2.1 The Aero Gas Turbine ........................................................................................ 29 2.1.1 The Turbofan .................................................................................................. 30 2.1.2 Improving efficiency of GT powered aircraft ................................................ 32 2.1.2.1 Pressure ratio .................................................................................................................... 32 2.1.2.2 Geared GT ........................................................................................................................ 32 2.1.2.3 Open rotor GT .................................................................................................................. 32 2.1.2.4 Airframe design ............................................................................................................... 33 2.1.2.5 Secondary power systems ................................................................................................ 33 2.1.2.6 Summary of methods to improve GT power aircraft effeciency ...................................... 34 2.2 Aircraft Secondary Power Systems ................................................................... 34 2.2.1 Secondary power offtake ............................................................................... 34 2.2.2 Comparison of Secondary Power Distribution Systems ................................ 36 2.2.2.1 Hydraulic ......................................................................................................................... 36 2.2.2.2 Pneumatic ......................................................................................................................... 40 2.2.2.3 Electrical .......................................................................................................................... 40 2.2.2.4 Summary of secondary power systems on traditional aircraft ......................................... 43 2 2.2.3 Electrification of Aircraft Secondary Power Systems ................................... 44 2.2.3.1 History of Aircraft Electrification .................................................................................... 44 2.2.3.2 The Advantages and Disadvantages of Aircraft Electrification ....................................... 45 2.2.3.3 Electrification of Hydraulic and Pneumatic Systems ....................................................... 47 2.2.3.4 Summary Aircraft Electrification ..................................................................................... 48 2.2.4 All-Electric Aircraft ....................................................................................... 49 2.2.5 More-Electric Aircraft .................................................................................... 50 2.2.5.1 Boeing 787 MEA ............................................................................................................. 51 2.2.5.2 More-Electric Engine ....................................................................................................... 51 2.2.6 Aero GT Electrical-Mechanical System ........................................................ 53 2.2.6.1 Mechanical offtake and drivetrain ................................................................................... 53 2.2.6.2 Electrical generation and distribution .............................................................................. 54 2.2.6.3 Electro-mechanical system .............................................................................................. 55 2.2.6.4 Impact of GT structure ..................................................................................................... 56 2.2.6.5 Design Challenges Associated with the More-Electric Aircraft ...................................... 57 2.2.7 Summary of electrical secondary power systems .......................................... 59 2.3 Electro-Mechanical Interaction ......................................................................... 60 2.3.1 Land based generation ................................................................................... 60 2.3.2 Industrial automation ..................................................................................... 61 2.3.2.1 Vibration mitigation by control ........................................................................................ 62 2.3.3 Automotive ..................................................................................................... 62 2.3.3.1 Drivetrain dynamics ......................................................................................................... 63 2.3.4 Marine ............................................................................................................ 64 2.3.5 Wind power generation .................................................................................. 65 2.3.6 Aero ................................................................................................................ 66 2.3.7 Summary of electro-mechanical interaction review ...................................... 67 2.4 Aero Electrical generation and distribution ..................................................... 68 2.4.1 Aero electrical generation system .................................................................. 68 2.4.1.1 Aero distribution solutions ............................................................................................... 69 2.4.1.2 Aero Generation Solutions ............................................................................................... 73 2.4.1.2 Summary of aircraft electrical generation and distribution methods ............................... 74 2.5 The Doubly-Fed Induction Generator .............................................................. 75 2.5.1 The DFIG system ........................................................................................... 75 2.5.2 Wind turbine applications .............................................................................. 76 2.5.3 DFIG operation .............................................................................................. 76 2.5.4 As an aero generator ...................................................................................... 77 2.5.5 Field Orientated Control ................................................................................ 78 2.5.5.1 Direct and indirect FOC ................................................................................................... 79 2.5.6 Review of DFIG control schemes .................................................................. 79 3 2.5.6.1 Control with rigid grid connection ................................................................................... 79 2.5.6.2 Stand-alone control .......................................................................................................... 80 2.5.7 Types of machine arrangement ...................................................................... 80 2.5.7.1 Brushless Doubly-Fed Induction Machine ....................................................................... 80 2.5.7.2 Cascaded induction machine ...........................................................................................