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

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of the batteries is kept between -22 ◦ C and +37 ◦ C [7]. The batteries will be maintained above0 ◦ C by a 500mW heater. According to Fig. 3.20, a beneficial side effect of the heater is tokeep the batteries capacity beyond 1,100mAh.Figure 3.20: Variation of voltage of KOKAM SLPB554374H during discharge for severaltemperatures [20].The batteries have been successfully tested in vacuum by Philippe Ledent.3.4 Battery protection circuitsThe KOKAM batteries are delivered with a protection circuit module (PCM). The role of thePCM is to protect the batteries against over-charge, over-discharge and over-currents. Thesemodules are directly soldered on the batteries terminals. Each battery has its own PCM.The choice can be made to keep that circuit or to make our own. Our first choice was touse the protection circuits of the manufacturer (KOKAM).The operating temperature range of the KOKAM PCM is -10 ◦ C to 50 ◦ C and the storagetemperature range of the KOKAM PCM is -20 ◦ C to 60 ◦ C. Given that the PCM is in directcontact with the batteries, and that the temperature of the batteries is maintained between0 ◦ C and 45 ◦ C, the temperature of the PCM is expected to stay in a good range.The schematics of the KOKAM PCM is shown on figure 3.21.3.4.1 Electrical characteristicThe electrical charateristics are shown in the table 3.4.34
Figure 3.21: Schematics of the KOKAM PCM [21].3.4.2 Over charge protection (i.e. over-voltage protection)The PCM disconnects the battery when the voltage reaches 4.275V. The connection is establishedagain when the voltage drops to 4.075V. This prevents the battery from beingdamaged by an over charge. However, to operate in optimal condition, the battery voltageshould not rise over 4.2V. Another circuit, the dissipation system, will be designed to preventthe batteries voltage to get over 4.2V.3.4.3 Over discharge protection (i.e. under-voltage protection)The PCM disconnects the battery if the voltage drops to 2.6V. The connection is establishedagain when the voltage is higher than 2.9V.3.4.4 Over current protectionThe over-current protection is a fuse. The fuse melts with a current between 2A and 4A(depending upon voltage). There will be two batteries in parallel, so that the current in eachbattery should not be higher than half of the current consumed in the CubeSat. Nevertheless,the CubeSat is supposed to be functional with only one battery. Then, the total currentconsumed in the satellite must be kept under 2A during eclipse.35
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 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 42 and 43: Figure 4.1: P-V curve of a solar pa
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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