MASTER THESIS Hardware and Software Implementation of a Control Pod for Airborne Wind ...

117 Pages·2012·4.44 MB·English

MASTER THESIS

Hardware and Software
Implementation of a Control Pod for
Airborne Wind Energy

Estudis: Enginyeria en
Electrònica/Màster d’Enginyeria
Electrònica
Autor: Josep Albert Caba Monton
Director/a: Daniel Toal
Any: 2011-2012
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To my family. Thanks for always being there for me.
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ACKNOWLEDGMENT

I would like to acknowledge the advice and guidance of Dr. Daniel Toal. I would also
like to thank Dr. Edin Omerdic for all the help and time spent teaching and helping me. Finally,
I want to thank Joseph Coleman, for his priceless help and unconditional support.
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TABLE OF CONTENTS

ACKNOWLEDGMENT ...................................................................................... 3
TABLE OF CONTENTS ...................................................................................... 4
TABLE OF FIGURES .......................................................................................... 6
TABLE OF TABLES.......................................................................................... 10
ABSTRACT .................................................................................................... 11
1. Introduction ............................................................................................ 12
1.1 Wind farming at high altitudes ..................................................................................... 12
1.2 Project introduction ...................................................................................................... 13
1.3 System Description ....................................................................................................... 14
2. HARDWARE ............................................................................................ 15
2.1 AIR PART GENERAL DIAGRAM ...................................................................................... 16
2.1.1 SbRIO ................................................................................................................... 16
2.1.2 IMU ...................................................................................................................... 19
2.1.3 MOTOR ................................................................................................................ 24
2.1.4 NI9505 ................................................................................................................. 27
2.1.5 ENCODER ............................................................................................................. 38
2.1.6 GPS ...................................................................................................................... 40
2.1.7 ISOLATION ........................................................................................................... 45
2.1.8 POWER SUPPLY ................................................................................................... 47
2.1.9 WIFI ..................................................................................................................... 60
2.1.10 FINAL BOARD ............................................................................................................. 63
3. SOFTWARE .............................................................................................. 64
3.1 IMU ............................................................................................................................... 64
3.2 MOTOR+NI9505 ............................................................................................................ 79
3.2.2 REAL-TIME PART .................................................................................................. 94
3.3 WIFI CONNECTION ........................................................................................................ 95
3.4 BATTERY CONTROL ....................................................................................................... 97
3.5 GPS ................................................................................................................................ 99
3.6 REAL-TIME PART ......................................................................................................... 101
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3.6.1 User Interface .................................................................................................... 101
3.6.2 Real-Time Implementation................................................................................ 103
4.FUTURE WORK ........................................................................................ 108
5.CONCLUSIONS ......................................................................................... 109
6.REFERENCES ............................................................................................ 111
APPENDIX ................................................................................................... 113
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TABLE OF FIGURES
Figure 1. Increasing windspeed and power density in relation to altitude(O'Gairbith 2010) .... 12
Figure 2.European Wind Atlas, (1989), Riso National Laboratory .............................................. 12
Figure 3.Winch with recovery motor .......................................................................................... 13
Figure 4.System Outline(Coleman,2011) .................................................................................... 14
Figure 5.Airborne and ground station hardware layout ............................................................. 15
Figure 6.Airborne layout ............................................................................................................. 16
Figure 7.Interface labview with SbRIO. ....................................................................................... 17
Figure 8.Real time interface with SbRIO's FPGA module ............................................................ 18
Figure 9.SPI communication example ......................................................................................... 19
Figure 10.Transceivers connection diagram ............................................................................... 20
Figure 11.Schematic of airbone's IMUs ....................................................................................... 21
Figure 12.Schematic of kite's IMU ............................................................................................... 22
Figure 13.Shematic of kite's IMU receiving part ......................................................................... 22
Figure 14.SbRIO'S IMU PCB ......................................................................................................... 23
Figure 15.Kite's IMU PCB ............................................................................................................. 23
Figure 16.Re40 operating range .................................................................................................. 24
Figure 17.DC motor rotor ............................................................................................................ 26
Figure 18.Dc motor model .......................................................................................................... 27
Figure 19.NI9505 block diagram ................................................................................................. 28
Figure 20.Encoder-ni9505 connection diagram .......................................................................... 29
Figure 21.Ni9505 current sensor schematic ............................................................................... 30
Figure 22.Current sense during on PWM period ........................................................................ 30
Figure 23. Current sense during off PWM period ....................................................................... 31
Figure 24.Relation between inductance and correct current measures .................................... 32
Figure 25.Instrumentation amplifier ........................................................................................... 33
Figure 26.Current sensor diagram .............................................................................................. 34
Figure 27.ADC SPI protocol ......................................................................................................... 34
Figure 28.ADC-Transduction from digital output into current ................................................... 35
Figure 29.Connection between the motor, ni9505 and current sensor ..................................... 35
Figure 30.H-bridge representation with clockwise direction ...................................................... 36
Figure 31.Two-Phase encoder output signals ............................................................................. 38
Figure 32.Mr-1024 CPT encoder output signal ........................................................................... 39
Figure 33.Gps 610-f picture ......................................................................................................... 40
Figure 34.2J402U external antenna ............................................................................................ 41
Figure 35.Antenna's gain at 5V ................................................................................................... 41
Figure 36.Serial communication example ................................................................................... 42
Figure 37.Gps board schematic ................................................................................................... 43
Figure 38.Gps board layout ......................................................................................................... 44
Figure 39.Position, Current consumption and speed when inverting motor direction .............. 45
Figure 40.Isolation of the ni9505 ................................................................................................ 46
Figure 41.Transceiver configuration ........................................................................................... 48
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Figure 42.Sensing,control and communication power conversion efficiency and consumption 49
Figure 43.Maximum duty cycle 50%, 0.02616Nm load ............................................................... 51
Figure 44. Maximum duty cycle: 50%, 0.01308Nm torque ......................................................... 51
Figure 45.Power consumption approximation ........................................................................... 52
Figure 46.Maximum duty cycle: 50%, 0.01308Nm torque.......................................................... 53
Figure 47.Power consumption approximation ........................................................................... 53
Figure 48.battery discharge CAPACITY (%).................................................................................. 56
Figure 49.Battery management schematics ............................................................................... 59
Figure 50.Wifi configuration ....................................................................................................... 60
Figure 51.Network diagram ........................................................................................................ 61
Figure 52.Final board schematics ................................................................................................ 63
Figure 53.Final board layout ....................................................................................................... 63
Figure 54.IMU-FPGA-Real-time interface data exchange ........................................................... 64
Figure 55.SPI protocol modes ..................................................................................................... 66
Figure 56.ADIS 16407 SPI data format ........................................................................................ 67
Figure 57.Writing and reading for adis16407 example ............................................................... 67
Figure 58.Time stall and read rate time ...................................................................................... 68
Figure 59.Table with burst mode registers ................................................................................. 68
Figure 60.Burst Mode .................................................................................................................. 69
Figure 61.SCLK generation code .................................................................................................. 69
Figure 62.One period of SCLK ...................................................................................................... 70
Figure 63.SCLK Generation of 16 falling edges ........................................................................... 70
Figure 64.CS generation .............................................................................................................. 70
Figure 65.One SCLK block with CS ............................................................................................... 71
Figure 66.Two SCLK blocks with CS ............................................................................................. 71
Figure 67.Mosi generation code ................................................................................................. 71
Figure 68.Mosi generation signal ................................................................................................ 72
Figure 69.Reading code ............................................................................................................... 72
Figure 70.MOSI and MISO implementation ................................................................................ 72
Figure 71.IMU implementation of the FPGA part ....................................................................... 73
Figure 72.Real signals obtained................................................................................................... 73
Figure 73.Burst mode code ......................................................................................................... 74
Figure 74.SPI signal at 1hz ........................................................................................................... 75
Figure 75.Zoom of SCLK's falling edge at 1Hz ............................................................................. 75
Figure 76.SPI signal at maximum speed ...................................................................................... 76
Figure 77.Zoom OF SCLK'S falling edge at maximum speed ....................................................... 77
Figure 78.SPI signal at maximum working speed ........................................................................ 77
Figure 79.SPI signal at maximum working frequency SCLK's falling edge zoom ......................... 78
Figure 80.Interaction between the four modules ....................................................................... 79
Figure 81.True count case ........................................................................................................... 81
Figure 82.False count case .......................................................................................................... 81
Figure 83.Communication with mcp3001 ................................................................................... 82
Figure 84.ADC reading code ........................................................................................................ 83
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Figure 85.ADC data conversion into current ............................................................................... 83
Figure 86.PWM generation LOOP (current trigger also present) ............................................... 84
Figure 87.Sample current loop .................................................................................................... 84
Figure 88.Only proportional control present .............................................................................. 85
Figure 89.Only integral control present ...................................................................................... 86
Figure 90.Proportional and integral control ............................................................................... 86
Figure 91.Proportional and derivative control ............................................................................ 87
Figure 92.PID control loop........................................................................................................... 87
Figure 93.Current loop code ....................................................................................................... 88
Figure 94.Position loop code ....................................................................................................... 88
Figure 95.Maximum duty Cycle=25%, No load ........................................................................... 89
Figure 96.Maximum duty Cycle=50%, No load ........................................................................... 89
Figure 97.Maximum duty Cycle=100%, No load ......................................................................... 90
Figure 98.Maximum duty Cycle=50%, No load, Inversion while turning ................................... 90
Figure 99.Maximum duty Cycle=100%, No load, Inversion while turning .................................. 90
Figure 100.Maximum duty cycle=25%, 0,02616Nm torque ....................................................... 91
Figure 101.Maximum duty cycle=50%, 0,02616Nm torque ....................................................... 91
Figure 102.Maximum duty cycle=100%, 0,02616Nm torque ..................................................... 91
Figure 103.Maximum duty cycle=25%,inversion while turning .................................................. 92
Figure 104.Maximum duty cycle=50%, INVERSION while turning .............................................. 92
Figure 105.Maximum duty cycle=25% ........................................................................................ 92
Figure 106Maximum duty cycle=50% ......................................................................................... 93
Figure 107Maximum duty cycle=25%, INVERSION while turning ............................................... 93
Figure 108Maximum duty cycle=50%, INVERSION while turning ............................................... 93
Figure 109.Project's explorer window ........................................................................................ 95
Figure 110.Air and ground pod, FPGA module ........................................................................... 95
Figure 111.Air and ground pod, Real-time module .................................................................... 96
Figure 112.ADC LabVIEW code .................................................................................................... 97
Figure 113.ADC output - equivalent cell charge ......................................................................... 97
Figure 114.ADC real-time module conversion ............................................................................ 98
Figure 115.GPS code ................................................................................................................... 99
Figure 116.GPRMC table ........................................................................................................... 100
Figure 117.GPS user interface ................................................................................................... 100
Figure 118.Real-time part, user interface ................................................................................. 101
Figure 119.Joystick control VI, user interface ........................................................................... 102
Figure 120.Airborne attitude and compass INDICATOR, user interface ................................... 102
Figure 121.Fpga initialization and waiting until ni9505s drivers are enabled .......................... 103
Figure 122.Real-time code ........................................................................................................ 104
Figure 123. XGYRO register conversion example ...................................................................... 105
Figure 124.Position graph code................................................................................................. 105
Figure 125. Current graph code ................................................................................................ 106
Figure 126.Speed graph code .................................................................................................... 106
Figure 127.Test Box ................................................................................................................... 109
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Figure 128.Outdoors test .......................................................................................................... 109
Figure 129.Avoided CO2 from renewable energy 1990 to 2008 .............................................. 110
Figure 127b.Mounted pod ........................................................................................................ 110
Figure 130.Final board connection diagram ............................................................................. 113
Figure 131.Two boards version connection diagram ................................................................ 114
Figure 132.PCB1 Conection:Transceiver IMU and Motor1 current Sensor .............................. 115
Figure 133. PCB2 Connection: Battery management ADC and Motor2 current Sensor ........... 116
Figure 134.Final board connection ........................................................................................... 117
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TABLE OF TABLES
Table 1.NI9505 protection .......................................................................................................... 28
Table 2.Current-voltage equivalence .......................................................................................... 33
Table 3.Current-voltage equivalence .......................................................................................... 33
Table 4.Sensors and communicaton part power consumption .................................................. 48
Table 5.Total power CONSUMPTION (without actuation part) using regulators ....................... 50
Table 6. Total power consumption (without actuation part) using dc/dc converters ................ 50
Table 7.Equivalence between gear-head’s input and output Speed .......................................... 51
Table 8.Battery comparison ........................................................................................................ 55
Table 9.sensing and communication parts power consumption ................................................ 56
Table 10.Power consumption with converters efficiency ........................................................... 57
Table 11.Motor power consumption .......................................................................................... 58
Table 12.Wifi comparison ........................................................................................................... 62
Table 13.Unit table of IMU's registers ...................................................................................... 104