Design and Implementation of On-board Electrical Power ... - OUFTI-1

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Figure 4.1: P-V curve of a solar panel for several insolation values (expressed in units ofG nom ) and at T = 15 ◦ C.P out = η −1 P in (4.2)where η is the efficiency of the corresponding converter. The efficiency of a converterdepends on the output current. However, for simplicity, we assume that this efficiency isconstant. The converters are indeed used in a limited range of output currents.Finally, percentages of utilization are attributed to each operation mode and the consumedpower is integrated on one orbit.4.3.1 Operation modes of subsystems and corresponding power needs• EPSEPS has two modes:• OBC1. ON: EPS is always active and 5mA are consumed (on batteries bus).2. ON+Heater: When active, the heater consumes around 500mW on the batteriesbus. This must be added to the consumption of EPS.OBC1 and OBC2 are always active and consume 10mW each. The OBC1 consumptionis 2mA on the 5V bus. The OBC2 consumption is 3.3mA on the 3.3V bus.• EPS2 (Experimental EPS)EPS2 has three modes:1. OFF: EPS2 consumes no power.42
Figure 4.2: P-V curve of a solar panel for tree temperatures and under a full insolation(G nom ).• COM2. Supply: it supplies the 3.3V bus, with an efficiency of at most 50% (for 100mA).In this case, the 3.3V converter of EPS lets EPS2 supply the subsystems. Theefficiency of EPS2 quickly decreases as the output current decreases. As a consequence,rather than setting an efficiency of 50% for the 3.3V bus when EPS2 isactive, we assume that a constant power of 300mW is consumed.3. Test: EPS2 supplies a load in which 100mA are dissipated, the efficiency is 50%(total 660mW consumed), and this lasts only a few seconds.COM has two modes:1. Rx only: COM is always “listenning” on the D-STAR and AX.25 receive (Rx)channel. Corresponding consumption is at most 20mA on the 3.3V bus.2. Rx + Tx (receive and transmit): When a D-STAR signal or AX.25 signal is transmitted,the COM consumption is 35 mA on the 3.3V bus and 208 to 347mA onthe 7.2V bus, these currents corresponding to Tx RF signal power of 750mW andan amplifier efficiency ranging from 30% to 50%.• BeaconBeacon is always active. Its consumption is 15mA on the 3.3V bus and 28 to 46mA onthe 7.2V bus, these currents corresponding to a Tx RF signal power of 100mW and anamplifier efficiency ranging from 30% to 50%.43
Page 2 and 3: AcknowledgementsI want to thank the
Page 4 and 5: Contents1 Introduction 91.1 Cubesat
Page 6 and 7: 4.4.2 Mean case . . . . . . . . . .
Page 8 and 9: B Power budget worksheet 106C Pictu
Page 10 and 11: design and the tests are delegated
Page 12 and 13: Chapter 2Requirements of the EPS2.1
Page 14 and 15: • The Single-Event Upset (SEU)Thi
Page 16 and 17: the P-POD. RBF pins must fit within
Page 18 and 19: Figure 2.6: Top view of the PC104 c
Page 20 and 21: Chapter 3Design of EPS architecture
Page 22 and 23: • Voltage (4) and current (5) at
Page 24 and 25: Figure 3.6: The equivalent circuit
Page 26 and 27: of our Lithium-Polymer batteries va
Page 28 and 29: Figure 3.12: I-V curve of a solar p
Page 30 and 31: 3.3.3 CapacityA important value to
Page 32 and 33: Parameter SLPB723870H4 SLPB554374HN
Page 34 and 35: of the batteries is kept between -2
Page 36 and 37: Over Charge Prohibition 4.275 ± 0.
Page 38 and 39: supplied in 5V. The circuit will be
Page 40 and 41: Chapter 4The Power Budget4.1 Introd
Page 44 and 45: 4.3.2 Efficiency of convertersTo at
Page 46 and 47: Figure 4.3: Consumptions in % in me
Page 48 and 49: Chapter 5Electrical Design of EPS5.
Page 50 and 51: V outV in= D. (5.1)Since D ≤ 1, t
Page 52 and 53: The power losses in the inductor ar
Page 54 and 55: ∆i L,1 + ∆i L,2 = 0, (5.16)V in
Page 56 and 57: Using the value of ∆i L given by
Page 58 and 59: There is no data about the case to
Page 60 and 61: Capacitor selectionFour 10µF ceram
Page 62 and 63: • Output voltage: 5V.• Maximum
Page 64 and 65: Figure 5.12: Burst mode operation (
Page 66 and 67: Figure 5.14: Simplified schematics
Page 68 and 69: Figure 5.15: Worksheet for 3.3V con
Page 70 and 71: sequently, the k was chosen above 0
Page 72 and 73: where G 1 is the initial control-to
Page 74 and 75: Figure 5.21: Measured Bode diagram
Page 76 and 77: Figure 5.26: Equivalence between th
Page 78 and 79: C f =12πf f R 0f,L f = R 2 0f C f
Page 80 and 81: Figure 5.37: Schematics of the firs
Page 82 and 83: R KR >1.45V100mA − 1.3A35= 23.07
Page 84 and 85: The schematics is shown on figure 5
Page 86 and 87: A commercial model meets all requir
Page 88 and 89: Figure 5.45: Schematics of the heat
Page 90 and 91: PrefixX7X5Y5Z5SuffixTemperature ran
Page 92 and 93:
6.2.1 The second dissipation system
Page 94 and 95:
• The antenna deployment system.
Page 96 and 97:
6.3.3 TestsThe engineering model of
Page 98 and 99:
7.3 ActivitiesAs OUFTI-1 is designe
Page 100 and 101:
8.1.2 DesignA model of Li-Po batter
Page 102 and 103:
[15] Fabien Jordan, Phase B Electri
Page 104 and 105:
TaK = 273 + TaC;%Photo-current ther
Page 106 and 107:
Appendix BPower budget worksheetIn
Page 108 and 109:
108
Page 110 and 111:
Appendix CPictures of the prototype
Page 112 and 113:
Appendix DSchematics of the enginee
Page 114 and 115:
876543213V3 CONVERTER AND INPUT FIL
Page 116:
87654321ANTENNA DEPLOYMENT CIRCUITB
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