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

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TaK = 273 + TaC;%Photo-current thermal coefficientK0 = 2.72e-4/Isc_Tref;%Photo-current (G=1 et T=Tref)Iph = Isc_Tref * G * (1 + K0*(TaK - Tref));%Diode saturation current (T=Tref)Id_Tref = Isc_Tref / (exp(q*Voc_Tref/(n*k*Tref))-1);%Diode saturation current (T=Tak)Id = Id_Tref * (TaK/Tref)^(3/n) * exp(-(Vg * q/(n*k))*(1/TaK - 1/Tref));%Calculation of serie resistance RsVpmax_Tref = 2.427; %voltage at maximum power for T=TrefIpmax_Tref = 0.529; %current at maximum power for T=TrefRs = (Voc_Tref-Vpmax_Tref)/Ipmax_Tref;%Iterative calculation of IscI = zeros(size(V));for i=1:10 \%number of iteration = 10for j=1:length(V);I(j) = I(j) - (Iph - I(j) - Id*(exp(q*(V(j)+I(j)*Rs)/(n*k*Tref)) -1))/...(-1 - (Id*(exp(q*(V(j)+I(j)*Rs)/(n*k*Tref)) -1))*q*Rs/(n*k*Tref));endendThe second function gives the voltage at the terminal of the used Schottky diode as afuntion of the current flowing in the diode.vmax = 3.5;function vv = v_diode(vi)% by Pierre Thirion% Use of function : V = v_diode(I)% V = Voltage on diode terminals [V]% V is computed by linear interpolation, on the basis of real measurements% of the I-V curve of the diode.% I = Current in the diode [A]% mesures (except the first)d_v = [0 0.141 0.213 0.227 0.24 0.25 0.26 0.27 0.280.3 0.32 0.34 0.36 0.38 0.39 0.4 0.41 0.42 0.44 0.460.48 0.5 0.52 0.54 0.56 0.58 ] ;d_i = [0 0.00001 0.00002 0.00003 0.0005 0.00007 0.0001 0.00017 0.000230.00047 0.00095 0.00206 0.0036 0.0095 0.015 0.021 0.031 0.04 0.072 0.1220.184 0.27 0.358 0.46 0.605 0.9 ];vv = zeros(size(vi));for k = 1:(length(vi)-1)104
endi = vi(k);dii = (d_i - i);co = 0;for j = 1:(length(dii)-1)if ((dii(j) 0))co = j;endend% linear interpolationif (co == 0)elsea = (i - d_i(co+1)) / (d_i(co) - d_i(co+1));v = d_v(co)*a + d_v(co+1)*(1-a);endvv(k) = v;The following code gives an exemple of the use of the above functions to plot to I-V andP-V curves of a solar cell under full insolation and at a temperature of 28 ◦ C.v = [0:0.05:vmax];ia = Cell_GaAs(v, 1, 25);da = v_diode(ia);va = 2*v-da;figure;plot(va,ia)AXIS([0 2*vmax 0 0.6])GRID ONXLABEL(’Voltage [V]’)YLABEL(’Current [A]’)figure;pa = ia.*va;plot(va,pa)AXIS([0 2*vmax 0 3])GRID ONXLABEL(’Voltage [V]’)YLABEL(’Power [W]’)105
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AcknowledgementsI want to thank the
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Contents1 Introduction 91.1 Cubesat
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4.4.2 Mean case . . . . . . . . . .
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B Power budget worksheet 106C Pictu
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design and the tests are delegated
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Chapter 2Requirements of the EPS2.1
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• The Single-Event Upset (SEU)Thi
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the P-POD. RBF pins must fit within
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Figure 2.6: Top view of the PC104 c
Page 20 and 21:
Chapter 3Design of EPS architecture
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• Voltage (4) and current (5) at
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Figure 3.6: The equivalent circuit
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of our Lithium-Polymer batteries va
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Figure 3.12: I-V curve of a solar p
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3.3.3 CapacityA important value to
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Parameter SLPB723870H4 SLPB554374HN
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of the batteries is kept between -2
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Over Charge Prohibition 4.275 ± 0.
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supplied in 5V. The circuit will be
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Chapter 4The Power Budget4.1 Introd
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Figure 4.1: P-V curve of a solar pa
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4.3.2 Efficiency of convertersTo at
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Figure 4.3: Consumptions in % in me
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Chapter 5Electrical Design of EPS5.
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V outV in= D. (5.1)Since D ≤ 1, t
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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 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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