CN102928714B - Moonlet sun array life forecast method based on I-V curve and energy balance - Google Patents

Abstract

The invention provides a moonlet sun array life forecast method based on I-V curve and energy balance. Aiming at the problems that the existing moonlet sun array life forecast method has few damage regularity space environment influencing factors, is limited in life forecast of unit cells to the large extent, cannot forecast the whole life of a sun array, and the like, the moonlet sun array life forecast method is based on space environment simulation tests, and a sun array integral life forecast module is provided taking important space environment factor influence including sun and earth distance factors, track earth shadow time, included angles of sun rays and sun array normals, temperature and sun radiation into account, further the problem of generality of life forecast taking the sun array important life influence factors into account and sun array integral life forecasting suitable for different bathes and different types is solved. The I-V curve is a current and voltage curve of a solar unit cell. The moonlet sun array life forecast method is based on tests, and has good model generality and strong engineering practical applicability.

Description

A kind of moonlet sun battle array life-span prediction method based on I-V curve and energy balance

Technical field

The invention belongs to moonlet sun battle array electric powder prediction, be specifically related to a kind of moonlet sun battle array life-span prediction method based on I-V curve and energy balance.

Background technology

Moonlet is applied to all space fields except manned space flight, is included in remote sensing, communication, navigation, technical identification, space science etc. and has brought into play important effect.Power-supply system is the key service system of satellite, be responsible for to produce, storage and for the whole life period of satellite provides the stable continual energy by electric loading for whole star, its power supply capacity, power supply quality directly affect operating state, reliability and the useful life of satellite.Performance, reliability that power-supply system is controlled have very high requirement.

Because different satellite transit tracks have its obvious environmental quality, cause the satellite system performance degradation rule and characteristic of different orbital motions to be distinguished to some extent.The orbit major part of moonlet is middle low orbit, affected by complex space environment, as: solar pressure, ionosphere, charged particle etc., the excursion of solar incident angle in 1 year is large, and moonlet turnover shadow is frequent, high and low temperature alternative conversion etc., sun battle array intermittent work often, operating time is short, and operating current is large, and high/low-temperature impact is violent.These factors inevitably will exert an influence to the performance of satellite and life-span.Final under the comprehensive function of inside and outside factor, cause thrashing.Fig. 1 has provided, because each subsystem failure of moonlet causes the shared ratio situation of moonlet global failure.Hence one can see that, and power-supply system lost efficacy and occupies most of ratio, and the inefficacy of sun battle array is the main factor that power-supply system lost efficacy.

Yet, because moonlet belongs to non repairable product, and be subject to the restriction of quality and size, can not take the method for redundant component to improve the reliability of moonlet sun battle array, make the life prediction of moonlet sun battle array play important guiding effect for design, production, the use of moonlet.

The method that is applied at present moonlet sun battle array life prediction under space environment condition can be summarized as: (one), ultraviolet acceleration lifetime test method: set up the ultraviolet acceleration lifetime test device under space environmental simulation, solar cell is carried out to ultraviolet acceleration lifetime test technical research, obtain the delta data of solar batteries along with the ultraviolet irradiation time.By experimental data processing, acquisition solar batteries, along with the attenuation law of equivalent ultraviolet irradiation time, adopts and adds severe judgement according to theory, the injuring rule of research ultra-violet radiation to solar cell, the battery life under prediction ultraviolet irradiation environment; (2), thermal strain extremum method: take experimental test as the fundamental analysis thermal strain development law of solar panel after thermal cycle repeatedly, proposition is usingd thermal strain maximum (or residual heat strain) as the Damage Parameter of multi-layer bonded joint structure, sets up the methods such as Mathematical Modeling in pre-shoot the sun monomer battery structure life-span.Wherein, ultraviolet acceleration lifetime test method has only been considered this space environment condition of ultraviolet, and compared with other life-span influencing factor, a little less than the impact relatively of ultraviolet, the single ultra-violet radiation of carrying out can not well disclose the injuring rule of sun battle array under complex space environment condition to the injuring rule research of sun battle array; Thermal strain extremum method is from having set up the data model of cell by test, for through experimental test, and only consider that the life prediction of cell under temperature impact is effective, for sun monomers such as different batches, different models, Life Prediction Model need to be re-established, and sun battle array bulk life time forecasting problem cannot be solved.

Summary of the invention

The problem existing for current moonlet sun battle array life prediction, the present invention proposes a kind of moonlet sun battle array life-span prediction method based on I-V curve and energy balance, on the basis of space environment simulation test, be structured in the sun battle array bulk life time forecast model under the important space such environmental effects such as angle, temperature, solar radiation of considering the solar distance factor, track ecliptic time, sunray and sun tactical deployment of troops line, and then part solves and considers the life prediction of the important life-span influencing factor of sun battle array and the versatility problem that sun battle array bulk life time is predicted.Electric current and voltage curve that described I-V curve is sun cell.

The technical solution used in the present invention is: a kind of moonlet sun battle array life-span prediction method based on I-V curve and energy balance, and the method realizes as follows:

The angle of step 1, the solar distance factor, track ecliptic time, sunray and sun tactical deployment of troops line is determined;

In the local time of according to orbit altitude, southbound node and prediction initial time, calculate the Changing Pattern of angle of the solar distance factor, orbital period Te, track ecliptic time, every rail sunray and the sun tactical deployment of troops line of every day, obtain time dependent quantitative data, for follow-up sun battle array I-V curve and Energy Balance Analysis;

Step 2, sun battle array I-V curve model are determined;

According to sun battle array characteristic, build sun battle array computation model, consider the impact of solar incident angle, irradiation decay, day ground factor, loss factor factor simultaneously, calculate sun battle array output voltage, output current under Various Seasonal, different track condition and different operating mode, to characterize sun battle array power output in real time and change in long term situation;

The I-V curvilinear characteristic point of standard state of take is parameter, considers the impact of multiple environmental factor on the sun battle array life-span, calculates the output characteristic of sun battle array; Utilize the computer analyzing model of formula (Equ.1) sun battle array I-V curve, obtain the I-V characteristic curve of the sun battle array under different condition; This model, when intensity of illumination is less than 2 solar constants, has very high accuracy; The light conditions of sun-synchronous orbit moonlet meets this condition:

$\left\{\begin{array}{c}I={\mathrm{Isc}}^{\′}(1-C_1\×\{\exp [V/(C_2\×V_{\mathrm{ov}}\′)]-1\left\}\right)\\ C_1=[1-({I_{\mathrm{mp}}}^{\′}/{\mathrm{Isc}}^{\′})]\×\left\{\exp \right[-{V_{\mathrm{mp}}}^{\′}/(C_2\×{V_{\mathrm{ov}}}^{\′}){]}^{}\}\\ C_2=[({V_{\mathrm{mp}}}^{\′}/{V_{\mathrm{ov}}}^{\′})-1]/1n(1-{I_{\mathrm{mp}}}^{\′}/{\mathrm{Isc}}^{\′})\end{array}\right.---(\mathrm{Equ}.1)$

In formula:

I---output current, unit is A;

Isc'---sun battle array short circuit current, canonical parameter or measured value, unit is A;

C ₁---formula coefficient 1;

V---sun battle array output voltage, unit is V;

C ₂---formula coefficient 2;

V _ov'---sun battle array open circuit voltage, canonical parameter or measured value, unit is V;

I _mp'---sun battle array best operating point output current, canonical parameter or measured value, unit is A;

V _mp'---sun battle array best operating point output voltage, canonical parameter or measured value, unit is V;

Sun battle array open circuit voltage and best operating point output voltage computation model are as follows:

$\left\{\begin{array}{c}{V}_{\mathrm{ov}}\′=(V_{\mathrm{ov}}+{\mathrm{\β}}_{\mathrm{VBOL}}\×(T-25))\×0.98\×0.98\×N_s\×K_{\mathrm{VRAD}}\\ V_{\mathrm{mp}}\′=(V_{\mathrm{mp}}+{\mathrm{\β}}_{\mathrm{VBOL}}\×(T-25))\×0.98\×0.98\×N_s\×K_{\mathrm{VRAD}}\end{array}\right.---(\mathrm{Equ}.2)$

In formula:

V _ov---single solar cell open circuit voltage, unit is V;

V _mp---single solar cell best effort point voltage, unit is V;

β _vBOL---single solar cell beginning of lifetime voltage temperature coefficient, unit is V/ ℃;

K _vRAD---sun battle array open circuit voltage irradiation declines and falls the factor;

T---sun battle array temperature, unit is ℃;

Sun battle array short circuit current and best operating point Current calculation model are as follows:

$\left\{\begin{array}{c}\mathrm{Isc}\′=({\mathrm{Isc}}_{}+{\mathrm{\α}}_I\×(T-25))\×0.98\×0.98\×0.98{\×N}_p\×\cos \mathrm{\θ}\left(t\right)\×F_{\mathrm{rd}}\×K_{\mathrm{IRAD}}\\ I_{\mathrm{mp}}\′=(I_{\mathrm{mp}}+{\mathrm{\α}}_I\×(T-25))\×0.98\×0.98\×0.98\×N_p\×\cos \mathrm{\θ}\left(t\right)\×F_{\mathrm{rd}}\×K_{\mathrm{IRAD}}\end{array}\right.---(\mathrm{Equ}.3)$

I _sC---single solar cell short circuit current, unit is A;

I _mp---single solar cell best operating point electric current, unit is A;

α _i-single solar cell current temperature coefficient, unit is A/ ℃;

θ (t)---the angle of sunray and sun battle array normal direction in a circle track, unit is degree;

T-sun battle array temperature, unit is ℃;

K _iRAD-sun battle array short circuit current irradiation declines and falls the factor;

F _rd---the solar distance factor;

Utilize the impact of " sun battle array open circuit voltage and short circuit current irradiation decline and falls factor computation model " prediction LEO track radiation environment on the decay of satellite solar cell output parameter, in this model, Isc is K _iRAD, Vov is K _vRAD;

A. mode input parameter-definition is as follows:

Battery types: unijunction GaAs solar cell; Quartz glass coverslip thickness: 120 μ m; Orbit altitude: 300km ~ 3000km; Inclination angle: only for 99 °; Chronomere: month;

B. model output parameter is defined as follows:

Peak power output P _max, short circuit current I _sc, open circuit voltage V _ov, its output form: provide P _max, I _scand V _ovafter m month, P _max, I _scand V _ovfor the percentage of initial value, provide P _max, I _scand V _ovfunction about time month;

For this sun battle array open circuit voltage and short circuit current irradiation decline, the computation model of the factor falls below:

Multiple orbital attitudes displacement damage dose is calculated as follows: x is orbit altitude, and month is month number in-orbit, and y is the displacement damage dose calculating;

When 300km<=x<=600km, computing formula is:

y＝14（A ₀+A ₁·x+A ₂·x ²+A ₃·x ³+A ₄·x ⁴+A ₅·x ⁵）·month （Equ.4）

Wherein, A0=-5.72637E6, A1=69074.68933, A2=-329.19032,

A3=0.77634，A4=-9.13546E-4，A5=4.49106E-7

When 600km<x<=1000km, computing formula is:

y＝14（A ₀+A ₁·x+A ₂·x ²+A ₃·x ³+A ₄·x ⁴）·month （Equ.5）

Wherein, A0=-5.80893E7, A1=321272.30685, A2=-663.23216, A3=0.59526, A4=-1.77968E-4 is when 1000km<x<=3000km, and computing formula is:

y＝14（A ₀+A ₁·x+A ₂·x ²+A ₃·x ³+A ₄·x ⁴+A ₅·x ⁵）·month （Equ.6）

Wherein, A0=5.01219E8, A1=-1.76649E6, A2=2453.54778,

A3=-1.65135，A4=5.32602E-4，A5=-5.18233E-8

The computation model of the Pmax of GaAs/Ge solar cell, Isc and Voc is:

Peak power output decay, the i.e. computation model of Pmax:

P _max=1.0-C×log10(1+(y/Dx)) （Equ.7）

Wherein, C=0.242, Dx=3.47e9, y is the displacement damage dose calculating;

Short circuit current decay, the i.e. computation model of Isc:

K _IRAD=Isc=1.0-C×log10(1+(y/Dx)) （Equ.8）

Wherein, C=0.213, Dx=8.3e19

Open circuit voltage decay, the i.e. computation model of Voc:

K _VRAD=Vov=1.0-C×log10(1+(y/Dx)) （Equ.9）

Wherein, C=0.07, Dx=1.8e9

Step 3, sun battle array energy balance computation model are determined;

When carrying out energy balance calculating, according to the data that data or ground provide in-orbit, the critical condition of energy balance is monitored in real time, if sun battle array provides the unnecessary electric weight Q of energy _residual(c) by the occasion of changing zero into, show that sun battle array is in major injury state, and Q _residual(c) calculating formula is:

$Q_{\mathrm{residual}}\left(c\right)=I_{\mathrm{SA}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-I_{\mathrm{load}\_\mathrm{mean}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-1.02\&times;{\&Integral;}_0^{\mathrm{te}}{I}_d\left(t\right)\&times;\mathrm{dt}---(\mathrm{Equ}.10)$

Wherein:

Q _residual(c)---c encloses the available unnecessary electric weight of sun battle array in-orbit, and unit is C;

Te---time shade phase, unit is s;

I _sA(c)---c encloses square formation current clamp point current value in-orbit, and unit is A;

I _{load_mean}(c)---illumination period load current I _load(A), it is that c encloses the mean value of load current each cycle in-orbit, and unit is A;

I _d(t)---the shade phase, battery discharging electric current, unit is A;

According to the equation of designated period of time sun battle array I-V curve, providing corresponding area of illumination busbar voltage V _{s_bus}and sun battle array isolating diode and power cable pressure drop sum V _{s_dioline}time, obtain sun battle array operating voltage clamped point V on this designated period of time I-V curve _op1the current value I at place _{s_op1}; From energy balance, calculated, the sun battle array of this designated period of time provides the unnecessary electric weight Q of energy _residual(c) can be expressed as:

$Q_{s-\mathrm{residual}}\left(c\right)=I_{s\_\mathrm{opl}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-I_{s\_\mathrm{load}\_\mathrm{mean}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-1.02\&times;{\&Integral;}_0^{\mathrm{te}}{I}_d\left(t\right)\&times;\mathrm{dt}---(\mathrm{Equ}.11)$

In formula:

I _{s_op1}---give directions sun battle array operating voltage clamped point V on I-V curve in period _op1the current value at place, unit is A;

I _{s_load_mean}---the mean value of all load current data of designated period of time area of illumination load current/in-orbit, unit is A;

I _d(t)---designated period storage battery is at the discharge current value in shadow region, and unit is A;

Sun battle array operating voltage point output power computation model is as follows;

P _sA(t)＝V _bus(t)Iop1(t)， I _sa(t)＝I _op1(t)

Further can obtain:

P _{s_op1}(c)＝V _{s_bus}(c)I _{s_op1}(c)

V _{s_op1}(c)＝V _{s_bus}(c)+V _{s_dioline} （Equ.12）

In formula:

In the circle orbital period constantly, from 0<t<Te, wherein, Te is the orbital period to t--c, and unit is s;

P _sA---sun battle array power output, unit is W;

P _{s_op1}(c)---c circle sun battle array is output as clamped point V _{s_op1}time power output, unit is W;

I _{s_op1}(c)---sun battle array operating voltage clamped point V on c circle I-V curve _{s_op1}time current value, unit is A;

V _{s_bus}---area of illumination busbar voltage, unit is V;

V _{s_dioline}---sun battle array isolating diode and power cable pressure drop sum, unit is V;

For power-supply system in-orbit, because making illumination period busbar voltage, power-supply controller of electric remains definite value, thereby, can think: under the prerequisite of the normal work of power-supply controller of electric, illumination period busbar voltage is constant all the time; Meanwhile, obtaining V _{s_dioline}after value, can be enough I-V curve by above-mentioned foundation obtain designated period of time clamped point current value I _{s_op}(c), for energy balance, calculate;

If system prediction obtains certain designated period of time Q _residual(c)=0, illustrates that now sun battle array is to the longevity;

Wherein, while carrying out the calculating of batteries discharging current, the discharging current of batteries depends on the discharge power of batteries, electric discharge regulator efficiency, batteries supply line fissipation factor, battery voltage factor;

Shadow region, batteries discharging current is:

$I_d\left(t\right)=\frac{(I_{\mathrm{load}}\left(t\right)-I_{\mathrm{SA}}\left(t\right))\&times;V_{\mathrm{bus}}}{{\mathrm{\&eta;}}_{\mathrm{BDR}}\&CenterDot;{\mathrm{\&eta;}}_{\mathrm{line}}\&CenterDot;V_{\mathrm{bat}}\left(t\right)}$

In formula:

In the circle orbital period constantly, from 0<t<Te, wherein, Te is the orbital period to t--c, and unit is s;

I _load(t)--the time dependent function of load current demand in-orbit; η _bDR--electric discharge regulator efficiency;

N _ine--batteries supply line fissipation factor;

V _bat(t)--batteries discharge voltage; Based on the track battery discharging first pressing of the circle of c in-orbit and electric discharge final pressure value, can think approx V _bat(t) by electric discharge, be just depressed into electric discharge final pressure linear change;

V _bus: busbar voltage during electric discharge, unit is V;

Wherein: shadow region sun battle array I _sA(t) electric current is zero, V _bat(t) be an integrand, this function is by storage battery discharge in-orbit first pressing and electric discharge final pressure definite linear function.

Wherein, described sun battle array temperature is calculated as follows by sun battle array temperature model:

Sun battle array temperature changes with the variation of satellite turnover shadow state, shadow zone, ground, and sun battle array temperature declines gradually, until be down to out the minimum temperature before shadow; Illumination period, sun battle array temperature rises rapidly from going out movie queen, until reach photoperiodic equalized temperature point, after this temperature remains unchanged until satellite enters the ground shadow phase of next rail ring, goes round and begins again;

The simplified model of sun battle array variations in temperature is as follows:

Within the ground shadow phase, sun battle array temperature drops to ground shadow phase minimum temperature from the highest photoperiodic equilibrium temperature linearity, goes out movie queen, and sun battle array temperature rose to 60 ℃ from ground shadow phase minimum temperature in 8 minutes, in 20 minutes, rise to the highest equilibrium temperature of illumination period from 60 ℃, until enter shadow next time;

The highest photoperiodic equilibrium temperature, the default value of shadow phase minimum temperature be respectively:

The highest photoperiodic equilibrium temperature T _sAS; Ground shadow phase minimum temperature T _sAE.

Advantage of the present invention is:

(1), influencing factor of many life-spans is comprehensive: the present invention be take test as basis, considers the sun battle array bulk life time forecast model under the important space such environmental effects such as angle, temperature, solar radiation of the solar distance factor, track ecliptic time, sunray and sun tactical deployment of troops line;

(2), model commonality: for sun-synchronous orbit moonlet sun battle array, comprising: the bulk life time of Si and all types of solar battery arrays of GaAs is predicted, avoided carrying out to specific monomer battery the limitation of life prediction;

(3), engineering practicability: the application's sun battle array life-span prediction method belongs to the method that physical model combines with data-driven.In modeling process, taked part simplified way, meanwhile, the parameter that the needed data of model gather based on existing moonlet, easily obtains, simplify the problems such as the complexity of Life Prediction Model and data acquisition difficulty, and then there is stronger engineering practicability.

Accompanying drawing explanation

Fig. 1 causes moonlet failure ratio row relations of distribution figure for each subsystem failure;

Fig. 2 is sun battle array life prediction flow chart;

Fig. 3 is moonlet solar cell characteristic parameter decay calculation flow chart;

Fig. 4 is sun battle array year solar distance factor variations law curve figure;

Fig. 5 is solar incident angle year Changing Pattern curve chart;

Fig. 6 is HY-1B moonlet sun battle array I-V curve chart;

Fig. 7 provides unnecessary electric weight temporal evolution curve chart for sun battle array.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in detail.

A moonlet sun battle array life-span prediction method based on I-V curve and energy balance, the method realizes as follows:

The angle of step 1, the solar distance factor, track ecliptic time, sunray and sun tactical deployment of troops line is determined;

In the local time of according to orbit altitude, southbound node and prediction initial time, call STK software, calculate the Changing Pattern of angle of the solar distance factor, orbital period Te, track ecliptic time, every rail sunray and the sun tactical deployment of troops line of every day, obtain time dependent quantitative data, for follow-up sun battle array I-V curve and Energy Balance Analysis.

Step 2, sun battle array I-V curve model are determined;

According to sun battle array characteristic, build sun battle array computation model, consider the impact of the factors such as solar incident angle, irradiation decay, day ground factor, loss factor simultaneously, calculate sun battle array output voltage, output current under Various Seasonal, different track condition and different operating mode, to characterize sun battle array power output in real time and change in long term situation.

The I-V curvilinear characteristic point of standard state of take is parameter, considers the impact of multiple environmental factor on the sun battle array life-span, calculates the output characteristic of sun battle array.Utilize the computer analyzing model of Equ.1 sun battle array I-V curve, can obtain the I-V characteristic curve of the sun battle array under different condition.This model, when intensity of illumination is less than 2 solar constants, has very high accuracy.The light conditions of sun-synchronous orbit moonlet meets this condition:

$\left\{\begin{array}{c}I={\mathrm{Isc}}^{\&prime;}(1-C_1\&times;\{\exp [V/(C_2\&times;V_{\mathrm{ov}}\&prime;)]-1\left\}\right)\\ C_1=[1-({I_{\mathrm{mp}}}^{\&prime;}/{\mathrm{Isc}}^{\&prime;})]\&times;\left\{\exp \right[-{V_{\mathrm{mp}}}^{\&prime;}/(C_2\&times;{V_{\mathrm{ov}}}^{\&prime;}){]}^{}\}\\ C_2=[({V_{\mathrm{mp}}}^{\&prime;}/{V_{\mathrm{ov}}}^{\&prime;})-1]/1n(1-{I_{\mathrm{mp}}}^{\&prime;}/{\mathrm{Isc}}^{\&prime;})\end{array}\right.---(\mathrm{Equ}.1)$

In formula:

I---sun battle array output current, unit is A;

ISC '---sun battle array short circuit current, canonical parameter or measured value, unit is A;

C ₁---formula coefficient 1;

V---sun battle array output voltage, unit is V;

C ₂---formula coefficient 2;

V _ov' _ _ _ _ _ battle array open circuit voltage, canonical parameter or measured value, unit is V;

I _mp'---sun battle array best operating point output current, canonical parameter or measured value, unit is A;

V _mp'---sun battle array best operating point output voltage, canonical parameter or measured value, unit is V.

(1) sun battle array characteristic feature point calculation of parameter model;

(1.1) sun battle array open circuit voltage and best operating point output voltage:

$\left\{\begin{array}{c}{V}_{\mathrm{ov}}\&prime;=(V_{\mathrm{ov}}+{\mathrm{\&beta;}}_{\mathrm{VBOL}}\&times;(T-25))\&times;0.98\&times;0.98\&times;N_s\&times;K_{\mathrm{VRAD}}\\ V_{\mathrm{mp}}\&prime;=(V_{\mathrm{mp}}+{\mathrm{\&beta;}}_{\mathrm{VBOL}}\&times;(T-25))\&times;0.98\&times;0.98\&times;N_s\&times;K_{\mathrm{VRAD}}\end{array}\right.---(\mathrm{Equ}.2)$

In formula:

V _ov---single solar cell open circuit voltage (AM0 of QJ 1019-1995 regulation, 25 ℃), unit is V;

V _mp---single solar cell best effort point voltage (AM0 of QJ 1019-1995 regulation, 25 ℃), unit is V;

β _vBOL---single solar cell beginning of lifetime voltage temperature coefficient (during 1 ℃ of the temperature change of solar cell, the changing value of its output voltage), unit is V/ ℃;

K _vRAD---sun battle array open circuit voltage irradiation declines and falls the factor;

T---sun battle array temperature, unit is ℃.

(1.2) sun battle array short circuit current and best operating point Current calculation model:

$\left\{\begin{array}{c}\mathrm{Isc}\&prime;=({\mathrm{Isc}}_{}+{\mathrm{\&alpha;}}_I\&times;(T-25))\&times;0.98\&times;0.98\&times;0.98{\&times;N}_p\&times;\cos \mathrm{\&theta;}\left(t\right)\&times;F_{\mathrm{rd}}\&times;K_{\mathrm{IRAD}}\\ I_{\mathrm{mp}}\&prime;=(I_{\mathrm{mp}}+{\mathrm{\&alpha;}}_I\&times;(T-25))\&times;0.98\&times;0.98\&times;0.98\&times;N_p\&times;\cos \mathrm{\&theta;}\left(t\right)\&times;F_{\mathrm{rd}}\&times;K_{\mathrm{IRAD}}\end{array}\right.---(\mathrm{Equ}.3)$

I _sC---single solar cell short circuit current (AM025 ℃ of condition of QJ 1019-1995 regulation), unit is A;

I _mp---single solar cell best operating point electric current (AM0 of QJ 1019-1995 regulation, 25 ℃ of conditions), unit is A;

α _i---single solar cell current temperature coefficient (during 1 ℃ of the temperature change of solar cell, the changing value of its output current), unit is A/ ℃;

θ (t)---the angle of sunray and sun battle array normal direction in a circle track, unit is degree;

T---sun battle array temperature, unit is ℃;

K _iRAD---sun battle array short circuit current irradiation declines and falls the factor;

F _rd---the solar distance factor.

(2) sun battle array open circuit voltage and short circuit current irradiation decline and fall factor computation model;

This model is for predicting the impact of LEO track radiation environment on the decay of satellite solar cell output parameter, and in model, Isc is K _iRAD, Vov is K _vRAD.

A. mode input parameter-definition is as follows:

Battery types: unijunction GaAs solar cell; Quartz glass coverslip thickness: 120 μ m; Orbit altitude: 300km ~ 3000km; Inclination angle: only for 99 °; Chronomere: month;

B. model output parameter is defined as follows:

Peak power output P _max, short circuit current I _sc, open circuit voltage V _ov(output form: provide P _max, I _scand V _ovafter m month, P _max, I _scand V _ovfor the percentage of initial value, provide P _max, I _scand V _ovfunction about time month);

Be below the calculating formula of this computation model:

(2.1) multiple orbital attitudes displacement damage dose calculates

X is orbit altitude, and month is month number in-orbit, and y is the displacement damage dose (proton displacement damage dose) calculating.

When 300km<=x<=600km, computing formula is:

y＝14（A ₀+A ₁·x+A ₂·x ²+A ₃·x ³+A ₄·x ⁴+A ₅·x ⁵）·month （Equ.4）

Wherein, A0=-5.72637E6, A1=69074.68933, A2=-329.19032,

A3=0.77634，A4=-9.13546E-4，A5=4.49106E-7

When 600km<x<=1000km, computing formula is:

y＝14（A ₀+A ₁·x+A ₂·x ²+A ₃·x ³+A ₄·x ⁴）·month （Equ.5）

Wherein, A0=-5.80893E7, A1=321272.30685, A2=-663.23216, A3=0.59526, A4=-1.77968E-4 is when 1000km<x<=3000km, and computing formula is:

y＝14（A ₀+A ₁·x+A ₂·x ²+A ₃·x ³A ₄·x ⁴+A ₅·x ⁵）·month （Equ.6）

Wherein, A0=5.01219E8, A1=-1.76649E6, A2=2453.54778,

A3=-1.65135，A4=5.32602E-4，A5=-5.18233E-8

(2.2) computation model of the Pmax of GaAs/Ge solar cell, Isc and Voc

Peak power output decay (computation model of Pmax):

P _max=1.0-C×log10(1+(y/Dx)) （Equ.7）

Wherein, C=0.242, Dx=3.47e9, y is the displacement damage dose calculating.

Short circuit current decay (computation model of Isc):

K _IRAD=Isc=1.0-C×log10(1+(y/Dx)) （Equ.8）

Wherein, C=0.213, Dx=8.3e19

Open circuit voltage decay (computation model of Voc):

K _VRAD=Vov=1.0-C×log10(1+(y/Dx)) （Equ.9）

Wherein, C=0.07, Dx=1.8e9

(3) sun battle array temperature model;

Sun battle array temperature changes with the variation of satellite turnover shadow state.Shadow zone, ground, sun battle array temperature declines gradually, until be down to out the minimum temperature before shadow; Illumination period, sun battle array temperature rises rapidly from going out movie queen, until reach photoperiodic equalized temperature point, after this temperature remains unchanged until satellite enters the ground shadow phase of next rail ring, goes round and begins again.

The simplified model of sun battle array variations in temperature is as follows:

Within the ground shadow phase, sun battle array temperature drops to ground shadow phase minimum temperature from the highest photoperiodic equilibrium temperature linearity, goes out movie queen, and sun battle array temperature rose to 60 ℃ from ground shadow phase minimum temperature in 8 minutes, in 20 minutes, rise to the highest equilibrium temperature of illumination period from 60 ℃, until enter shadow next time.

The highest photoperiodic equilibrium temperature, the default value of shadow phase minimum temperature be respectively:

The highest photoperiodic equilibrium temperature T _sAS; Ground shadow phase minimum temperature T _sAE.

Step 3, sun battle array energy balance computation model;

(1) energy balance is calculated;

According to the data that data or ground provide in-orbit, the critical condition of energy balance is monitored in real time, if sun battle array provides the unnecessary electric weight Q of energy _esidual(c) by the occasion of changing zero into, show that sun battle array is in major injury state, and Q _esidual(c) calculating formula is:

$Q_{\mathrm{residual}}\left(c\right)=I_{\mathrm{SA}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-I_{\mathrm{load}\_\mathrm{mean}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-1.02\&times;{\&Integral;}_0^{\mathrm{te}}{I}_d\left(t\right)\&times;\mathrm{dt}---(\mathrm{Equ}.10)$

Wherein:

Q _residual(c)---c encloses the available unnecessary electric weight of sun battle array in-orbit, and unit is C;

Te---time shade phase, unit is s;

I _sA(c)---c encloses square formation current clamp point current value in-orbit, and unit is A;

I _{load_mean}(c)---illumination period load current I _load(A) (mean value of c circle load current each cycle in-orbit), unit is A;

I _d(t)---the shade phase, battery discharging electric current, unit is A;

From ' sun battle array operating voltage point output power computation model ', according to the equation of designated period of time sun battle array I-V curve, providing corresponding area of illumination busbar voltage V _{s_bus}and sun battle array isolating diode and power cable pressure drop sum V _{s_dioline}time, can obtain sun battle array operating voltage clamped point V on this designated period of time I-V curve _op1the current value I at place _{s_opl}.From energy balance, calculated, the sun battle array of this designated period of time provides the unnecessary electric weight Q of energy _esidual(c) can be expressed as:

$Q_{s-\mathrm{residual}}\left(c\right)=I_{s\_\mathrm{opl}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-I_{s\_\mathrm{load}\_\mathrm{mean}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-1.02\&times;{\&Integral;}_0^{\mathrm{te}}{I}_d\left(t\right)\&times;\mathrm{dt}---(\mathrm{Equ}.11)$

In formula:

I _{s_op1}---give directions sun battle array operating voltage clamped point V on I-V curve in period _op1the current value at place;

I _{s_load_mean}---the mean value of all load current data of designated period of time area of illumination load current/in-orbit;

I _d(t)---designated period storage battery is at the discharge current value in shadow region;

If system prediction obtains certain designated period of time Q _residual(c)=0, illustrates that now sun battle array is to the longevity.

(2) sun battle array operating voltage point output power computation model;

P _SA(t)＝V _bus(t)I _op1(t)， I _SA(t)＝I _op1(t)

Further can obtain:

P _{s_OP1}(c)＝V _{s_bus}(c)I _{s_op1}(c)

V _{s_op1}(c)＝V _{s_bus}(c)+V _{s_dioline} （Equ.12）

In formula:

In the circle orbital period constantly, from 0<t<Te(wherein, Te is the orbital period to t--c), unit is s;

P _sA---sun battle array power output, unit is W;

P _{s_OP1}(c)---c circle sun battle array is output as clamped point V _{s_op1}time power output, unit is W;

I _{s_opl}(c)---sun battle array operating voltage clamped point V on c circle I-V curve _{s_op1}time current value, unit is A;

V _{s_bus}---area of illumination busbar voltage, unit is V;

V _{s_dioline}---sun battle array isolating diode and power cable pressure drop sum, unit is V;

For power-supply system in-orbit, because making illumination period busbar voltage, power-supply controller of electric remains definite value, thereby, can think: under the prerequisite of the normal work of power-supply controller of electric, illumination period busbar voltage is constant all the time; Meanwhile, after obtaining Vs_dioline value, can be enough I-V curve by above-mentioned foundation obtain designated period of time clamped point current value I _{s_op1}(c), for energy balance, calculate.

(3) battery discharging Current calculation;

The discharging current of batteries depends on the discharge power of batteries, the factors such as regulator efficiency, batteries supply line fissipation factor, battery voltage of discharging.

Shadow region, batteries discharging current is:

$I_d\left(t\right)=\frac{(I_{\mathrm{load}}\left(t\right)-I_{\mathrm{SA}}\left(t\right))\&times;V_{\mathrm{bus}}}{{\mathrm{\&eta;}}_{\mathrm{BDR}}\&CenterDot;{\mathrm{\&eta;}}_{\mathrm{line}}\&CenterDot;V_{\mathrm{bat}}\left(t\right)}$

In formula:

In the circle orbital period constantly, from 0<t<Te(wherein, Te is the orbital period to t--c), unit is s;

I _load(t)--the time dependent function of load current demand in-orbit;

η _bDR--electric discharge regulator efficiency

η _line--batteries supply line fissipation factor

V _bat(t)--batteries discharge voltage; Based on the track battery discharging first pressing of the circle of c in-orbit and electric discharge final pressure value, can think approx V _bat(t) by electric discharge, be just depressed into electric discharge final pressure linear change;

V _bus: busbar voltage during electric discharge, unit is V;

Wherein: shadow region sun battle array I _sA(t) electric current is zero, V _bat(t) be an integrand, this function is by storage battery discharge in-orbit first pressing and electric discharge final pressure definite linear function.This patent is only considered the life prediction problem of sun battle array; suppose that all normal or storage batterys of storage battery and power-supply controller of electric operating state and power-supply controller of electric performance degradation do not exert an influence to sun battle array; thereby, herein storage battery discharge in-orbit first pressing and electric discharge final pressure can process by definite value.

Embodiment 1 is as follows:

The present invention is a kind of moonlet sun battle array life-span prediction method based on I-V curve and energy balance, described life-span prediction method is sun battle array performance degradation process to be considered as to the degenerative process of energy balance, thereby, having considered under moonlet running space environmental factor (comprising: the angle of the solar distance factor, track ecliptic time, sunray and sun tactical deployment of troops line, temperature, solar radiation etc.) impact, set up the sun battle array comprehensive life forecast model with better versatility.Figure 2 shows that the overview flow chart of life-span prediction method of the present invention, concrete implementation step is as follows:

The angle of step 1, the solar distance factor, track ecliptic time, sunray and sun tactical deployment of troops line is determined;

In the local time of according to orbit altitude, southbound node and prediction initial time, call STK software, calculate the Changing Pattern of the angle of the solar distance factor, orbital period, track ecliptic time, track sunray and sun tactical deployment of troops line, obtain time dependent quantitative data, for follow-up sun battle array I-V curve and Energy Balance Analysis.

Step 2, sun battle array I-V curve model;

(1) sun battle array open circuit voltage and short circuit current irradiation decline and fall factor computation model;

What Fig. 3 provided is the quantitative calculation process of LEO track radiation environment to solar cell characteristic parameter influence of fading.In conjunction with Fig. 3, first, according to moonlet orbit altitude displacement calculating damage dose function y=f (month) (wherein, relevant parameter is referring to Equ.4 ~ Equ.6) over time.

Secondly, utilizing formula Equ.8-9 to calculate respectively sun battle array open circuit voltage irradiation declines and falls factor function K over time _vRAD=gv (month) declines and falls factor function K over time with sun battle array short circuit current irradiation _iRAD=gI (month).

(2) sun battle array characteristic feature point calculation of parameter model;

For computing formula Equ.2-3, wherein, V _ov, V _op, β _vBOL, I _sC, I _mp, α _i, N _pn _sbe all known parameters data; θ (t), F _rdby above-mentioned steps, calculate; K _iRAD, K _vRADfunction for month; By sun battle array temperature model, obtained the temperature data of illumination period sun battle array.Above-mentioned parameter data and function are brought into Equ.2 and can obtain sun battle array open circuit voltage and best operating point output voltage, sun battle array short circuit current and best operating point electric current, can be expressed as follows:

$\left\{\begin{array}{c}{V}_{\mathrm{ov}}\&prime;=V_{\mathrm{ov}}\left(\mathrm{month}\right)\\ V_{\mathrm{mp}}\&prime;=V_{\mathrm{mp}}\left(\mathrm{month}\right)\end{array}\right.$ $\left\{\begin{array}{c}\mathrm{Isc}\&prime;=\mathrm{Isc}\left(\mathrm{month}\right)\\ I_{\mathrm{mp}}\&prime;=I_{\mathrm{mp}}\left(\mathrm{month}\right)\end{array},---(\mathrm{Equ}.14)\right.$

Formula Equ.14 is brought into Equ.1, respectively computing formula coefficient C ₁, C ₂, and then can set up the time dependent rule of sun battle array I-V curve, can be expressed as:

I＝V(month) （Equ.15）

By three characteristic points on I-V curve, be open circuit voltage point (V _oc'), short circuit current point (I _sC') and maximum power point (I _mp', V _mp') with the illumination under different condition, temperature and irradiation loss coefficient, revise after, this analytical expression of substitution, can obtain the I-V characteristic curve of the sun battle array under different condition.

Step 3, sun battle array energy balance computation model;

By V _{s_bus}, V _{s_dioline}value is calculated V by Equ.12 _{s_op1}value, calculates corresponding I by formula Equ.15 _{s_op1}value, and then set up I _{s_opl}and the functional relation between time month;

For the parameter η in Equ.13 _bDR, η _line, V _busfor known quantity, at shadow region I _sA(t) be zero, I _load(t) utilize existing moonlet in-orbit the average of load current data do approximate processing, i.e. I _load(t) :=I _{load_mean}(c), wherein, ' :=' expression ' being defined as ', I _sA(t)=0A.

Battery discharging Current calculation: shade phase, battery discharging electric current I _d(t) V in formula _bat(t) as an integrand.This function is by storage battery discharge in-orbit first pressing and electric discharge final pressure definite linear function, and its electric discharge first pressing is constant, and electric discharge final pressure is by having moonlet battery discharging final pressure mean approximation.

For Equ.11Te, te is known, V _{s_op1}and integration item can be asked by foregoing description, I _{s_load_mean}(c) utilize existing moonlet illumination period load current mean approximation.Above-mentioned parameter, bring Equ.11 into, due to I _{s_load_mean}(c) * (Te-te) and be approximately constant term, and I _{s_op1}(c) by Equ.12 and Equ.15, determined, thereby, I _{s_op1}(c) can be expressed as: I _{s_op1}(c)=I _{s_op1}(month), final, obtain Q _{s_residual}(c)=Q _{s_residual}(month), obtain the time dependent function of unnecessary electric weight that sun battle array provides energy, thereby can determine the sun battle array life-span.

Embodiment 2 is as follows:

It is object that the present embodiment be take China space flight HY-1B moonlet sun battle array, by elaborating of the present embodiment, further illustrates implementation process of the present invention and engineering application process.

The angle of step 1, the solar distance factor, track ecliptic time, sunray and sun tactical deployment of troops line is determined;

15:00PM ± 30min in the local time of moonlet orbit altitude 645km, southbound node---in the local time of according to orbit altitude, southbound node and prediction initial time, call STK software, calculate solar distance factor F _rd, orbital period, track ecliptic time, track sunray and sun tactical deployment of troops line the Changing Pattern of angle theta (t), obtain time dependent quantitative data, for follow-up sun battle array power output, calculate and Energy Balance Analysis.

F _rd=[1,033 1.023 1.008 0.991 0.977 0.968 0.968 0.976 0.991 1.008 1.024 1.033] (the solar distance factor of every month in a year, as shown in Figure 4); Orbital period: Te=100.8min; Track ecliptic time: te=33.5217min minute; Solar incident angle θ (t) has periodically, is illustrated in figure 5 solar incident angle year variation rule curve.

Step 2, sun battle array I-V curve model;

(1) sun battle array open circuit voltage and short circuit current irradiation decline and fall factor computation model;

Because the orbit altitude of HY-1B moonlet is 645km, according to formula Equ.5 displacement calculating damage dose y month Changing Pattern: y=f (month) in time.Utilizing formula Equ.8-9 to calculate respectively sun battle array open circuit voltage irradiation declines and falls factor function K over time _vRAD=gv (month) declines and falls factor function K over time with sun battle array short circuit current irradiation _iRAD=gI (month).

(2) sun battle array characteristic feature point calculation of parameter model;

For computing formula Equ.2-3, wherein, V _ov=2.65V, V _mp=2.32V, β _vBOL=-6.7mV/ ° C, I _sC=0.396A, I _mp=0.375A, a _i=0.014mA/cm ²° C, N _p=114, N _s=18, T=82 ° of C(be from sun battle array temperature model, illumination period, and sun battle array temperature can rise to rapidly equilibrium temperature, thereby this sentences the highest equilibrium temperature T _sAS=82 ° of C are as HY-1B moonlet sun battle array temperature); θ (t), F _rdby step 1, provided, and K _vRAD=gv (month), K _iRAD=gI (month).And then, set up respectively shape as the expression formula of Equ.14, the expression formula obtaining is brought into Equ.1, and finally set up the time dependent rule of HY-1B moonlet sun battle array I-V curve, Fig. 6 is the I-V curve of a certain given time in HY-1B moonlet sun battle array life cycle.

Step 3, sun battle array energy balance computation model;

By V _{s_bus}=29.3V, V _{s_dioine}=2.0 V values are calculated V by Equ.12 _{s_op1}=31.3V value, calculates corresponding I by formula Equ.15 _{s_op1}value, and then set up I _{s_op1}and the functional relation I between time month _{s_opl}=I _{s_opl}(month);

For the parameter η in Equ.13 _bOR=0.92, η _line=0.9673, V _bus=28.6V is known quantity, I _load(t), at shadow region I _sA(t)=0A, as calculated: I _load(t) :=I _{load_mean}(c)=9.0A, wherein, ' :=' expression ' being defined as '.

The shade phase, battery discharging electric current I _d(t) V in formula _bat(t) as an integrand.This function is by storage battery discharge in-orbit first pressing and electric discharge final pressure definite linear function, and its electric discharge first pressing is constant, electric discharge final pressure is by having moonlet battery discharging final pressure mean approximation, and electric discharge first pressing is 1.383 V*18(batteries Series Sheet accumulator body numbers)=24.8940V, electric discharge final pressure average 21.6V.

Te=100.8min, te=33.5217min, and by the V calculating _{s_op1}and i _{s_load_mean}(c)=11.4A brings Equ.11 into, due to I _{s_load_mean}(c) * (Te-te) and be approximately constant term, and I _{s_op1}(c) by Equ.12 and Equ.15, determined, thereby, I _{s_op1}(c) can be expressed as: I _{s_op1}(c)=I _{s_op1}(month), thus, Equ.11 is converted into Q _{s_residual}(c)=Q _{s_residual}(month), obtain the time dependent function of unnecessary electric weight that sun battle array provides energy, Figure 7 shows that unnecessary electric weight curve over time.As seen from the figure, unnecessary electric weight, along with the solar distance factor, under the comprehensive function of the cycle influencing factors such as solar incident angle, presents obvious periodicity, and unnecessary electric weight continuous decrease, is sun battle array end of life position with horizontal line intersection.

Claims (2)

1. the moonlet sun battle array life-span prediction method based on I-V curve and energy balance, is characterized in that: the method realizes as follows:

The angle of step 1, the solar distance factor, track ecliptic time, sunray and sun tactical deployment of troops line is determined;

In the local time of according to orbit altitude, southbound node and prediction initial time, calculate the Changing Pattern of angle of the solar distance factor, orbital period Te, track ecliptic time, every rail sunray and the sun tactical deployment of troops line of every day, obtain time dependent quantitative data, for follow-up sun battle array I-V curve and Energy Balance Analysis;

Step 2, sun battle array I-V curve model are determined;

According to sun battle array characteristic, build sun battle array computation model, consider the impact of solar incident angle, irradiation decay, the solar distance factor, loss factor factor simultaneously, calculate sun battle array output voltage, output current under Various Seasonal, different track condition and different operating mode, to characterize sun battle array power output in real time and change in long term situation;

The I-V curvilinear characteristic point of standard state of take is parameter, considers the impact of multiple environmental factor on the sun battle array life-span, calculates the output characteristic of sun battle array; Utilize the computer analyzing model of formula (Equ.1) sun battle array I-V curve, obtain the I-V characteristic curve of the sun battle array under different condition; This model, when intensity of illumination is less than 2 solar constants, has very high accuracy; The light conditions of sun-synchronous orbit moonlet meets this condition:

$\left\{\begin{array}{c}I={I_{\mathrm{SC}}}^{\&prime;}\&times;(1-C_1\&times;\{\exp [V/(C_2\&times;{V_{\mathrm{ov}}}^{\&prime;})]-1\left\}\right)\\ C_1=[1-({I_{\mathrm{mp}}}^{\&prime;}/{I_{\mathrm{SC}}}^{\&prime;})]\&times;\left\{\exp \right[-{V_{\mathrm{mp}}}^{\&prime;}/(C_2\&times;{V_{\mathrm{ov}}}^{\&prime;})\left]\right\}\\ C_2=[({V_{\mathrm{mp}}}^{\&prime;}/{V_{\mathrm{ov}}}^{\&prime;})-1]/\ln (1-{I_{\mathrm{mp}}}^{\&prime;}/{I_{\mathrm{SC}}}^{\&prime;})\end{array}\right.---(\mathrm{Equ}.1)$

In formula:

I---sun battle array output current, unit is A;

I _sC'---sun battle array short circuit current, canonical parameter or measured value, unit is A;

C ₁---formula coefficient 1;

V---sun battle array output voltage, unit is V;

C ₂---formula coefficient 2;

V _ov'---sun battle array open circuit voltage, canonical parameter or measured value, unit is V;

I _mp'---sun battle array best operating point output current, canonical parameter or measured value, unit is A;

V _mp'---sun battle array best operating point output voltage, canonical parameter or measured value, unit is V;

Sun battle array open circuit voltage and best operating point output voltage computation model are as follows:

$\left\{\begin{array}{c}{V_{\mathrm{ov}}}^{\&prime;}=(V_{\mathrm{ov}}+{\mathrm{\&beta;}}_{\mathrm{VBOL}}\&times;(T-25))\&times;0.98\&times;0.98\&times;\mathrm{Ns}\&times;K_{\mathrm{VRAD}}\\ {V_{\mathrm{mp}}}^{\&prime;}=(V_{\mathrm{mp}}+{\mathrm{\&beta;}}_{\mathrm{VBOL}}\&times;(T-25))\&times;0.98\&times;0.98\&times;\mathrm{Ns}\&times;K_{\mathrm{VRAD}}\end{array}\right.---(\mathrm{Equ}.2)$

In formula:

V _ov---single solar cell open circuit voltage, unit is V;

V _mp---single solar cell best effort point voltage, unit is V;

β _vBOL---single solar cell beginning of lifetime voltage temperature coefficient, unit is V/ ℃;

K _vRAD---sun battle array open circuit voltage irradiation declines and falls the factor;

T---sun battle array temperature, unit is ℃;

N _sfor known parameters data;

Sun battle array short circuit current and best operating point Current calculation model are as follows:

$\left\{\begin{array}{c}{I_{\mathrm{SC}}}^{\&prime;}(I_{\mathrm{SC}}+{\mathrm{\&alpha;}}_I\&times;(T-25))\&times;0.98\&times;0.98\&times;0.98\&times;N_P\&times;\cos \mathrm{\&theta;}\left(t\right)\&times;F_{\mathrm{rd}}\&times;K_{\mathrm{IRAD}}\\ {I_{\mathrm{mp}}}^{\&prime;}=(I_{\mathrm{mp}}+{\mathrm{\&alpha;}}_I(T-25))\&times;0.98\&times;0.98\&times;0.98\&times;N_P\&times;\cos \mathrm{\&theta;}\left(t\right)\&times;F_{\mathrm{rd}}\&times;K_{\mathrm{IRAD}}\end{array}\right.---(\mathrm{Equ}.3)$

I _sC---single solar cell short circuit current, unit is A;

I _mp---single solar cell best operating point electric current, unit is A;

α _i---single solar cell current temperature coefficient, unit is A/ ℃;

θ (t)---the angle of sunray and sun battle array normal direction in a circle track, unit is degree;

T---sun battle array temperature, unit is ℃;

K _iRAD---sun battle array short circuit current irradiation declines and falls the factor;

F _rd---the solar distance factor;

N _pfor known parameters data;

Utilize the impact of " sun battle array open circuit voltage and short circuit current irradiation decline and falls factor computation model " prediction LEO track radiation environment on the decay of satellite solar cell output parameter, in this model, Isc is K _iRAD, Vov is K _vRAD;

A. mode input parameter-definition is as follows:

Battery types: unijunction GaAs solar cell; Quartz glass coverslip thickness: 120 μ m; Orbit altitude: 300km～3000km; Inclination angle: only for 99 °; Chronomere: month;

B. model output parameter is defined as follows:

Peak power output P _max, short circuit current I _sc, open circuit voltage V _ov, its output form: provide P _max, I _scand V _ovafter m month, P _max, I _scand V _ovfor the percentage of initial value, provide P _max, I _scand V _ovfunction about time month;

Below for being somebody's turn to do " sun battle array open circuit voltage and short circuit current irradiation decline and falls factor computation model ":

Multiple orbital attitudes displacement damage dose is calculated as follows: x is orbit altitude, and month is month number in-orbit, and y is the displacement damage dose calculating;

When 300km<=x<=600km, computing formula is:

y＝14(A ₀+A ₁·x+A ₂·x ²+A ₃·x ³+A ₄·x ⁴+A ₅·x ⁵)·month (Equ.4)

Wherein, A0=-5.72637E6, A1=69074.68933, A2=-329.19032,

A3＝0.77634，A4＝-9.13546E-4，A5＝4.49106E-7

When 600km<x<=1000km, computing formula is:

y＝14(A ₀+A ₁·x+A ₂·x ²+A ₃·x ³+A ₄·x ⁴)·month (Equ.5)

Wherein, A0=-5.80893E7, A1=321272.30685, A2=-663.23216, A3=0.59526, A4=-1.77968E-4

When 1000km<x<=3000km, computing formula is:

y＝14(A ₀+A ₁·x+A ₂·x ²+A ₃·x ³+A ₄·x ⁴+A ₅·x ⁵)·month (Equ.6)

Wherein, A0=5.01219E8, A1=-1.76649E6, A2=2453.54778,

A3＝-1.65135，A4＝5.32602E-4，A5＝-5.18233E-8

The computation model of the Pmax of GaAs/Ge solar cell, Isc and Voc is:

Peak power output decay, the i.e. computation model of Pmax:

P _max＝1.0-C×log10(1+(y/Dx)) (Equ.7)

Wherein, C=0.242, Dx=3.47e9, y is the displacement damage dose calculating;

Short circuit current decay, the i.e. computation model of Isc:

K _IRAD＝Isc＝1.0-C×log10(1+(y/Dx)) (Equ.8)

Wherein, C=0.213, Dx=8.3e19

Open circuit voltage decay, the i.e. computation model of Voc:

K _VRAD＝Vov＝1.0-C×log10(1+(y/Dx)) (Equ.9)

Wherein, C=0.07, Dx=1.8e9

Step 3, sun battle array energy balance computation model are determined;

When carrying out energy balance calculating, according to the data that data or ground provide in-orbit, the critical condition of energy balance is monitored in real time, if sun battle array provides the unnecessary electric weight Q of energy _residual(c) by the occasion of changing the arbitrary value that is less than or equal to zero into, show that sun battle array is in major injury state, and Q _residual(c) calculating formula is:

$Q_{\mathrm{residual}}\left(c\right)=I_{\mathrm{SA}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-I_{\mathrm{load}\_\mathrm{mean}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-1.02\&times;{\&Integral;}_0^{\mathrm{te}}{I}_d\left(t\right)\&times;\mathrm{dt}---(\mathrm{Equ}.10)$

Wherein:

Q _residual(c)---c encloses the available unnecessary electric weight of sun battle array in-orbit, and unit is C;

Te is the orbital period, and unit is s;

Te---time shade phase, unit is s;

I _sA(c)---c encloses square formation current clamp point current value in-orbit, and unit is A;

I _{load_mean}(c)---illumination period load current I _load(A), it is that c encloses the mean value of load current each cycle in-orbit, and unit is A;

I _d(t)---the shade phase, battery discharging electric current, unit is A;

According to the equation of designated period of time sun battle array I-V curve, providing corresponding area of illumination busbar voltage V _{s_bus}and sun battle array isolating diode and power cable pressure drop sum V _{s_dioline}time, obtain sun battle array operating voltage clamped point V on this designated period of time I-V curve _op1the current value I at place _{s_op1}; From energy balance, calculated, the sun battle array of this designated period of time provides the unnecessary electric weight Q of energy _residual(c) can be expressed as:

$Q_{S\_\mathrm{residual}}\left(c\right)=I_{s\_\mathrm{op}1}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-I_{S\_\mathrm{load}\_\mathrm{mean}}\left(c\right)\&times;(\mathrm{Te}-\mathrm{te})-1.02\&times;{\&Integral;}_0^{\mathrm{te}}{I}_d\left(t\right)\&times;\mathrm{dt}---\mathrm{Equ}.11$

In formula:

I _{s_op1}---give directions sun battle array operating voltage clamped point V on I-V curve in period _op1the current value at place, unit is A;

I _{s_load_mean}---the mean value of all load current data of designated period of time area of illumination load current/in-orbit, unit is A;

I _d(t)---designated period storage battery is at the discharge current value in shadow region, and unit is A;

Sun battle array operating voltage point output power computation model is as follows:

P _SA(t)＝V _bus(t)I _op1(t)，I _SA(t)＝I _op1(t)

Further can obtain:

P _{s_op1}(c)＝V _{s_bus}(c)I _{s_op1}(c)

V _{s_op1}(c)＝V _{s_bus}(c)+V _{s_dioline} (Equ.12)

In formula:

T--c moment in the circle orbital period, 0<t<Te, wherein, Te is the orbital period, unit is s;

P _sA---sun battle array power output, unit is W;

P _{s_op1}(c)---c circle sun battle array is output as clamped point V _{s_op1}time power output, unit is W;

I _{s_op1}(c)---sun battle array operating voltage clamped point V on c circle I-V curve _{s_op1}time current value, unit is A;

V _{s_bus}---area of illumination busbar voltage, unit is V;

V _{s_dioline}---sun battle array isolating diode and power cable pressure drop sum, unit is V;

For power-supply system in-orbit, because making illumination period busbar voltage, power-supply controller of electric remains definite value, thereby, can think: under the prerequisite of the normal work of power-supply controller of electric, illumination period busbar voltage is constant all the time; Meanwhile, obtaining V _{s_dioline}after value, can be enough I-V curve by above-mentioned foundation obtain designated period of time clamped point current value I _{s_op1}(c), for energy balance, calculate;

If system prediction obtains certain designated period of time Q _residual(c)=0, illustrates that now sun battle array is to the longevity;

Wherein, while carrying out the calculating of batteries discharging current, the discharging current of batteries depends on the discharge power of batteries, electric discharge regulator efficiency, batteries supply line fissipation factor, battery voltage factor;

Shadow region, batteries discharging current is:

$I_d\left(t\right)=\frac{(I_{\mathrm{load}}\left(t\right)-I_{\mathrm{SA}}\left(t\right))\&times;V_{\mathrm{bus}}}{{\mathrm{\&eta;}}_{\mathrm{BDR}}\&CenterDot;{\mathrm{\&eta;}}_{\mathrm{line}}\&CenterDot;V_{\mathrm{bat}}\left(t\right)}---(\mathrm{Equ}.13)$

In formula:

T--c moment in the circle orbital period, 0<t<Te, wherein, Te is the orbital period, unit is s;

I _load(t)--the time dependent function of load current demand in-orbit;

η _bDR--electric discharge regulator efficiency;

η _line--batteries supply line fissipation factor;

V _bat(t)--batteries discharge voltage; Based on the track battery discharging first pressing of the circle of c in-orbit and electric discharge final pressure value, can think approx V _bat(t) by electric discharge, be just depressed into electric discharge final pressure linear change;

V _bus: busbar voltage during electric discharge, unit is V;

Wherein: shadow region sun battle array I _sA(t) electric current is zero, V _bat(t) be an integrand, this function is by storage battery discharge in-orbit first pressing and electric discharge final pressure definite linear function.

2. a kind of moonlet sun battle array life-span prediction method based on I-V curve and energy balance according to claim 1, is characterized in that: described sun battle array temperature is calculated as follows by sun battle array temperature model:

Sun battle array temperature changes with the variation of satellite turnover shadow state, shadow zone, ground, and sun battle array temperature declines gradually, until be down to out the minimum temperature before shadow; Illumination period, sun battle array temperature rises rapidly from going out movie queen, until reach photoperiodic equalized temperature point, after this temperature remains unchanged until satellite enters the ground shadow phase of next rail ring, goes round and begins again;

The simplified model of sun battle array variations in temperature is as follows:

Within the ground shadow phase, sun battle array temperature drops to ground shadow phase minimum temperature from the highest photoperiodic equilibrium temperature linearity, goes out movie queen, and sun battle array temperature rose to 60 ℃ from ground shadow phase minimum temperature in 8 minutes, in 20 minutes, rise to the highest equilibrium temperature of illumination period from 60 ℃, until enter shadow next time;

The highest photoperiodic equilibrium temperature, the default value of shadow phase minimum temperature be respectively:

The highest photoperiodic equilibrium temperature T _sAS; Ground shadow phase minimum temperature T _sAE.