JP2002270877A - Method for simulation-calculating solarlight generating amount and computer readable data storage medium with calculating program recorded therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that since a general method for drawing I-V, P-V curves in a designated solar radiation intensity/solar battery temperature from characteristics values (Isc, Iop, Vop, Voc, α, β, Rs, K) in a reference state (solar radiation intensity 1 kw/m<2> , solar battery temperature of 25 deg.C) of the solar battery is not established, a method for accurately calculating the monthly and yearly solarlight generating amounts by simulating for general purpose is not sufficiently established. SOLUTION: A method for calculating by simulating the solarlight generating amount comprises the steps of (1) obtaining basic characteristic value (IL, Co, n, Rsh, Rs) at 20, b and c deg.C as a general purpose method for forming the I-V curve at the solar radiation intensity, solar battery temperature designated from the I-V curve of the reference state, obtaining the basic characteristic values at the designated temperature by a curve interpolation, obtaining the values by a Newton method by using these values, and forming the I-V curve. Or, the method comprises the steps of (2) converting the points of the I-V curve of the reference state via a 'practical I-V curve conversion formula', and forming the I-V curve. The generating amount is calculated by simulating by applying these two methods to a practical use and as a core part of the 'solarlight generating amount simulating calculating program'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION As shown in FIG.
It converts solar light energy directly into electrical energy. That is, an electromotive force is generated by applying a photovoltaic effect, which is a kind of photoelectric effect. When light (photon) with appropriate energy enters the solar cell,
Free electrons and holes are generated. Pn in solar cell semiconductor
The electrons and holes that have reached the vicinity of the junction diffuse to the n-type semiconductor side and the p-type semiconductor side, respectively, and collect at both electrode portions, so that power can be taken out and a voltage and a current are generated. The present invention relates to a method for accurately predicting (simulating) the annual power generation of a solar cell, in addition to predicting and calculating the monthly and annual solar energy incident on the light receiving surface of a solar cell actually installed. In general, in order to accurately predict and calculate the amount of solar cell power generated each month and year, the voltage-current curve (IV kerf)
It is necessary to obtain the maximum power or the power at the operating voltage by using this IV curve and to integrate and obtain it.
The present invention relates to a method for producing an IV kerf and a PV kerf in a solar cell and a method for calculating a solar power generation amount using the method.

[0002]

2. Description of the Related Art An example of an annual simulation calculation of solar radiation energy received by a solar cell is a report of a commissioned work result of the New Energy Agency (Japan Meteorological Association).
"R & D of technology for developing photovoltaic power generation systems for practical use: Basic research on power generation" (1987)). However, in this report, there is hardly any case in which the calculation of solar radiation energy on the light receiving surface is performed by accurate simulation calculation up to the power generation amount of the solar cell. As an example of accurate simulation calculation up to the power generation, a paper published by the present inventors, that is, a paper 1 of the Institute of Electrical Engineers of Japan (Iga et al .:
"Development of PV power generation simulation calculation program using IV kerf creation method", Denki Kagaku D115 vol.6,199
Only seen in 5). The reason why there is no accurate prediction calculation up to the power generation amount is that the technique for drawing the IV curve at the specified solar radiation intensity and solar cell temperature has not been sufficiently established. The present inventor has described the “practical IV kerf” as a technique for drawing this IV kerf described in the above-mentioned paper 1 of the Institute of Electrical Engineers of Japan.
We have invented a method of creating power generation and have already developed a simulation calculation method for power generation using this method. However, in the “method of preparing a practical IV kerf” described in this paper, the IV kerf of the solar cell to be calculated is based on the IV kerf of a specific single-crystal solar cell (Showa Shell Sekiyu GL133) in the standard state.
The question remains whether it can be applied to other single-crystal solar cells, polycrystalline and amorphous solar cells accurately.

[0003]

In view of the state of the prior art as described above, a more general-purpose and accurate IV kerf preparation method was invented, and a simulation calculation of the amount of photovoltaic power generation was carried out using the method. What you want to do. In the present invention, the IV kerf at a specified solar radiation intensity and solar cell temperature is used.
As a method of creating the characteristic values, the characteristic values (Isc, Iop, V) of the reference state of the calculation target solar cell (solar intensity 1 KW / m ² , solar cell temperature 25 ° C.)
op, Voc, Rs) to obtain the basic characteristic value (IL, Co, n, Rsh) by solving the basic characteristic equation of the solar cell.
V-curves are being created. Then, based on the IV kerf in the reference state, the IV kerf at the solar radiation intensity and solar cell temperature designated by the following two methods (1) and (2) is drawn. (1) At a solar radiation intensity of 1 kw / m ² , the standard temperature (a ° C = 25 ° C)
From IV kerf at other temperatures (b ° C, c ° C)
-V kerf is calculated, basic characteristic values (IL, Co, n, RsR, Rs) at each temperature are obtained, and the basic characteristic values at the designated temperature are respectively obtained by curve interpolation. Then, from these basic characteristic values, Create an IV calf with the specified temperature and solar radiation intensity. (2) For each point on the IV kerf in the reference state,
V-curve conversion formula "to convert to specified temperature and solar radiation intensity.

[0004]

According to a first aspect of the present invention, there is provided a method for calculating a simulation of a solar power generation amount, wherein a basic formula of a solar cell is I = IL-IO * {exp (q (V + RsI) / nKoT) -1}-(V + RsI) / Rsh IO = CoT ³ exp (-qEg / nKoT) where I: output current [A] Co: saturation current temperature coefficient V: output voltage [V] Eg: energy gap [eV] IL: photovoltaic Current [A] T: Absolute temperature of solar cell element [K] IO: Saturation current [A] Ko: Boltzmann constant [J / K] Rs: DC resistance [Ω] q: Electric charge [C] Rsh: Parallel resistance [Ω] n: For each of the basic characteristic values (IL, Co, n, Rsh, Rs) in the junction constant, obtain the values of a ° C., b ° C., and c ° C., and use the solar cell basic formula again to obtain each a ° C. , B ° C, and c ° C, the respective basic characteristics (IL, Co,
n, Rsh, Rs), create a voltage-current curve (IV curve) at the specified solar radiation intensity and solar cell temperature, calculate the Pmax point on this IV curve, or the power at the specified voltage, and calculate this month / year. It is characterized by integrating and calculating the monthly and annual power generation. The method for calculating a simulation of the amount of photovoltaic power generation according to claim 2 is to create a voltage-current curve in a reference state from the solar cell characteristic values (Isc, Iop, Vop, Voc) by a solar radiation / temperature conversion formula. A voltage-current curve (IV curve) at the designated solar radiation intensity and designated solar cell temperature is created from the curve, the Pmax point on this IV curve or the power at the designated voltage is calculated, and this is integrated monthly and yearly to obtain a monthly and yearly sum. It is characterized by calculating the amount of power generation. The method for calculating the amount of simulation of the amount of photovoltaic power generation according to claim 3 includes, together with the features of claim 1, {01} voltage V, current I, photovoltaic current IL at a solar radiation intensity of 1 kw / m ² , saturation current temperature coefficient Co, junction constant n, parallel resistance Rs
Function including h, series resistance Rs, and solar cell temperature T (absolute temperature): Func (V, I, IL, Co, n, Rsh, Rs, T) = IL-CoT ³ exp (-
qEg / nk0T) * (exp (q * (V + Rs * I) / (n * k0 * T)) -1)-(V + Rs *
I) / Rsh-I, and then {02} the function Func (V,
A function obtained by differentiating I, IL, Co, n, Rsh, Rs, T) with a variable V: Dif (V, I,
IL, Co, n, Rsh, Rs, T) were created, and the {03} solar cell's reference state (solar cell temperature Ta (298 K (ta = 25 ° C.)), solar radiation intensity Ea (1
kw / m ² )) The short circuit current Isca and the optimum current I
opa-point P1 (0, Isca), P2 of the optimum voltage Vopa and the open circuit voltage Voca
Select (Vopa, Iopa), P3 (Voca, 0), {04}
(V, I, IL, Co, n, Rsh, Rs, T) = T at reference temperature T (298
K), the value of the series resistance Rs at the reference temperature Rsa, and the P1, P2,
Substituting the value of point P3 and setting IL, Co, n, and Rsh as unknowns.Relational expression: Func (0, Isca, IL, Co, n, Rsh, Rsa, Ta) = 0, Relational expression: Func (Voca , 0, IL, Co, n, Rsh, Rsa, Ta) = 0, Relationship: Func (Vopa, Iopa, IL, Co, n, Rsh, Rsa, Ta) = 0 Dif (V, I, IL, Co, n, Rsh, Rs, T) = 0
Into the reference state temperature Ta (298 K), the value Rsa at the reference temperature and the value of the point P2 (Vopa, Iopa) to the series resistance Rs, IL, Co, n, Rsh as unknown, Relational expression: Dif (Vopa, Iop
a, IL, Co, n, Rsh, Rsa, Ta) = 0, and then {06} the four relational expressions: Func (0, Isca, IL, Co, n, Rsh, Rsa, Ta) = 0,
Func (Voca, 0, IL, Co, n, Rsh, Rsa, Ta) = 0, Func (Vopa, Iopa,
IL, Co, n, Rsh, Rsa, Ta) = 0, Dif (Vopa, Iopa, IL, Co, n, Rsh, R
A solution A (ILa, Coa, na, Rsha) satisfying sa, Ta) = 0 is calculated by a nonlinear solution program, and then the {07} function: Func (V, I, IL, Co, n, Rsh, Rs, T) = 0 IL, Co, n, Rsh
Substituting the solution A (ILa, Coa, na, Rsha), further substituting the value of the reference state temperature Ta (298 K) and the series resistance Rs for T, and the relational expression of the variables V and I: Func (V , I, ILa, Coa, na, Rsha, Rsa, T
a) = 0, and {08} This equation is again solved by a nonlinear solution program for about 40 to 50 points of V with respect to V, and the voltage (V) -current (I) and voltage (V) in the reference state are obtained. )-Power (P)
(Power (P) = Voltage (V) x Current (I)) (approximately 40-50 points)
And the voltage V-current I curve (IV
Curve), voltage V-power P curve (PV curve), and then {09} the solar radiation intensity Eb of the solar cell (here 1kw
/ m ^2), the solar cell temperature Tb (absolute temperature: TbK = tb (℃) Voltage at + 273) Vb, for determining the current Ib, solar radiation intensity in the reference state of the solar cell Ea (1kw / m ^2), a solar cell Temperature Ta
(298 K: absolute temperature: Ta = ta + 273), the short-circuit current Isca, the series resistance Rsa, and the short-circuit current Is when the temperature changes by 1 ° C.
the open circuit voltage when the temperature changes by 1 ° C.
Voc fluctuation value β and curve correction factor K Conversion equation (Va, Ia) → (Vb, Ib): Ib = Ia + α * (tb-ta) Vb = Va + β * (tb-ta)-Rsa * (Ib-Ia)-K * Ib * (tb
-ta), and each of the voltage-current points created in the above {08} or each point on the IV curve connecting the points is Ia, V
Use as a value irradiance Eb (1kw / m ^2), the solar cell temperature Tb
Find each point (voltage Vb-current Ib: about 40-50 points) in (K),
Create IV curve and PV curve connecting these points,
Next, from the IV curve created in {10} above {09}, any five non-adjacent points are selected, and these points (VQ1, I
Q1), (VQ2, IQ2), (VQ3, IQ3), (VQ4, IQ4), (VQ5, IQ5) Substituting 0 for variables V, I, and making IL, Co, n, Rsh, Rs an unknown number, Relational expression: Func (VQ1, IQ1, IL, Co, n, Rsh, Rs, Tb) = 0, Relational expression: Func (VQ2, IQ2, IL, Co, n, Rsh, Rs, Tb) = 0, Relational expression: Func (VQ3, IQ3, IL, Co, n, Rsh, Rs, Tb) = 0, Relational expression : Func (VQ4, IQ4, IL, Co, n, Rsh, Rs, Tb) = 0, relational expression: Create Func (VQ5, IQ5, IL, Co, n, Rsh, Rs, Tb) = 0, The solution B (ILb, Cob, nb, Rshb, Rsb) of the five relational expressions is calculated by a nonlinear solution program, and then {11}
Voltage at the solar cell's solar radiation intensity Ec (here, 1 kw / m ² ) and solar cell temperature Tc (absolute temperature: Tc (K) = tc (° C) +273)
Regarding the relationship between Vc and current Ic, similarly to the above {09}, the conversion equation (Va, Ia) → (Vc, Ic): Ic = Ia + α * (tc−ta) Vc = Va + β * (tc− ta)-Rsa * (Ic-Ia)-K * Ic * (tc
-Create an IV curve and PV curve using ta), {12}
Select any five points that are not close to each other on the IV curve created in {11} and calculate their values (VR1, IR1), (VR2, IR2), (VR
3, IR3), (VR4, IR4), (VR5, IR5) with the above relational expression: Func (V, I, I
(L, Co, n, Rsh, Rs, Tc) = 0
Relational expression: Func (VR1, IR1, IL, Co, n, Rsh, Rs, Tc) = 0, Relational expression: Func (VR2, IR2, IL, Co, n, Rsh, Rs , Tc) = 0, Relational expression: Func (VR3, IR3, IL, Co, n, Rsh, Rs, Tc) = 0, Relational expression: Func (VR4, IR4, IL, Co, n, Rsh, Rs, Tc ) = 0, relational expression: Func (VR5, IR5, IL, Co, n, Rsh, Rs, Tc) = 0, and the solution C (ILc, Coc, nc, Rshc, Rsc) of the five relational expressions
Is calculated by the nonlinear solution program, and then {13} is specified (that is, at each time every month)
The solar radiation intensity Em and the solar cell temperature tm are taken in, and the temperature ta (25 ° C .: absolute temperature Ta (K) = ta (° C.) + 2 in the {14} reference state is taken.
73), the solution A (ILa, Coa, na, Rsha) of the {06} and the solution B (ILa, Coa, na, Rsha) of the {10} at the temperature tb (Celsius: Tb = tb + 273).
b, Cob, nb, Rshb, Rsb), the solution C (ILc, Coc, nc, Rshc, Rsc) of the {12} at the temperature tc (Celsius: Tc = tc + 273) and the input value Rsa, respectively (IL, Co , n, Rsh, Rs), curve interpolation is performed for three points, and the characteristic value M (ILm, Com, n
m, Rshm, calculates Rsm), then after corrected by {15} IL by irradiance Em actually measured the ^{ILm 'm = ILm × Em ÷} Ea (Ea = 1 (KW / m 2), wherein Relational expression: Func (V, I, IL, Co, n, Rsh, R
s, T) = 0 by substituting IL ^′ m, Com, nm, Rshm, Rsm, and Func (V, I,
IL ^′ m, Com, nm, Rshm, Rsm, Tm) = 0, and the voltage (V) -current
The relationship (I) (approximately 40 to 50 points) is obtained by a nonlinear solution program, and the relationship between voltage (V) and current (I) or I
-V curve and PV curve are created, and {16} the power at the Pmax point on this IV kerf or the power at the voltage specified as a parameter is calculated, and this value is calculated as the power value for each month and time, and is integrated monthly and yearly. It is characterized by calculating monthly and annual power generation. According to a fourth aspect of the present invention, in addition to the feature of the second aspect, the solar power generation amount simulation calculation method fetches a solar radiation intensity Em and a solar cell temperature tm specified at {20} (that is, at each time every month), and {21} the {}. Reference conditions created from 01｝ to 08 ｛(insolation intensity 1 kw / m ² , solar cell temperature 25
C)), the conversion formula (Va, Ia) → (Vk, Ik) using the Isca, α, β, Rsa, k of {09} with respect to the voltage Va−current Ia value (about 40 to 50 points): Ik = Ia + Isca * (Em / Ea-1) + α * (tm-ta) Vk = Va + β * (tm-ta)-Rsa * (Ik-Ia)-K * Ik * (tm
-ta), convert these voltage V-current I value or IV curve and PV curve connecting them, and {22} power at Pmax point on this IV kerf or power at voltage specified as parameter , And this value is used as a power value for each time of each month to calculate the monthly / annual power generation amount by monthly / annual integration. A computer-readable data storage medium storing a processing program of the method for calculating a simulation of the amount of photovoltaic power generation according to claim 5,
The invention described in 2, 3, or 4 is characterized in that these methods include a processing program that can be executed.

The features of the first, second, third and fourth aspects of the present invention are not limited to a specific single-crystal solar cell, but include other single-crystal solar cells.
Also for polycrystalline and amorphous solar cells, the IV kerf of the specified solar radiation intensity and solar cell temperature can be generally and accurately created, and the power generation amount of the solar cell can be accurately calculated by simulation. The features of the first and third aspects are that, similarly to the second and fourth aspects, in addition to being able to simulate and calculate the power generation amount of the solar cell with high accuracy, the solar radiation intensity is 1 KW / m ² at other temperatures. If characteristic values (for example, Isc, Iop, Vop, Voc at 55 ° C., etc.) are given, by using these values,
Even if α, β, Rs, and K are not available, an IV kerf of designated solar radiation intensity and solar cell temperature can be created, and simulation calculation of power generation can be performed. The feature of claim 5 is that since it is computer-readable from a storage medium in which a simulation calculation program for the amount of solar radiation and the amount of power generation according to the first, second, third, and fourth aspects is recorded, the amount of solar power generation under arbitrary conditions can be easily determined. Simulation calculation is possible,
It is directly useful for a wide range of applications in the design and operation of solar power generation systems.

Here, matters and terms related to the present invention will be described. First, an outline of a photovoltaic power generation simulation calculation program will be described (see IEEJ paper 1).
FIG. 2 shows a block diagram of the solar power generation amount simulation calculation program, and includes three subprograms: (1) (solar cell) light receiving surface solar radiation energy calculation subprogram, and (2) solar cell (module) temperature calculation. It consists of a subprogram and (3) a solar cell output calculation subprogram.

(1) The characteristics of the solar radiation energy calculation subprogram on the light receiving surface are as follows: The solar radiation amount of a solar cell installed at an arbitrary point, an inclination or an azimuth, or a solar cell of various tracking methods during a designated period is accurately determined. The base of the calculation time is 30 minutes, including the calculation of the solar cell calculation described later, so that the calculation can be performed. -As a method of obtaining the solar radiation on the light receiving surface of the solar cell, as shown in Fig. 3, the total solar radiation on the horizontal plane is separated into direct light components and scattered light components, and the light receiving surface solar radiation intensity is calculated by a method with high calculation accuracy for each. And the total amount of solar radiation on the light-receiving surface of the sun, including the amount of solar radiation reflected on the ground. -Monthly average-In order to calculate the monthly average daily amount of solar radiation from the total daily amount of solar radiation, it is obtained by a method having high calculation accuracy as shown in FIG. 4 in the following procedure. a. Calculate the sunrise and sunset times on the 15th of each month. b. Y = a * s so that the monthly average minus the total solar radiation is the area of the basic sine curve (the horizontal hatching in FIG. 4)
Find a of in (π / to * t). Where t ₀ is (sunset-sunrise)
It's time. c. Y = so that the monthly average-total daily solar radiation is the area of the sine curve twice as long as the period (the vertical hatching in FIG. 4)
Find b of b · sin ((2π / to) * t-π / 2) + b d. The value of y at each time is obtained from the formula of the basic sine curve (b) and the sine curve of twice the cycle (c), and the average value is defined as the solar radiation intensity at each time.

(2) The features of the solar cell module temperature calculation subprogram are as follows:-Intensity of light on the light-receiving surface at each monthly average time (every 30 minutes: the same applies hereinafter) calculated in (1) above; Using the input values of the outside air temperature and the wind speed for each monthly average time calculated from the outside air temperature, the solar cell (module) temperature is obtained by a multiple regression equation.

(3) As described above, the characteristics of the solar cell output calculation subprogram are as follows. In the prior art, the IV kerf at each month and each time is based on the IV kerf of a specific sun at best, as described in the IEEJ Technical Paper 1. Creating. An object of the present invention is to provide a general-purpose IV kerf creation method which is not limited to a specific type of solar cell and a solar cell power generation amount simulation calculation method using the method.

Next, terms and the like will be described. O The temperature of a solar cell is generally called "solar cell module temperature", but in the present invention, is shortened and also called "solar cell temperature". This temperature is usually measured with a thermocouple embedded in the solar cell module. In addition, the solar cell is called by the name of cell → module → array depending on the stage of its configuration.

Regarding the symbols used for the solar cell temperature, t (° C.) shown in lower case is Celsius and T is shown in upper case.
(K) indicates the absolute temperature. That is, T (K) = t (° C.) + 273. The capital letter T is mainly used in the solar cell basic formula, and t is used in other places.

Regarding the output and power generation amount of the solar cell, the product of the instantaneous generated voltage V and the instantaneous generated current I of the solar cell is called the output (unit: W or KW) of the solar cell, and the integrated value of the time is the power generation amount. (Unit wh or kwh).

The basic characteristic formula of the solar cell is as follows. I = IL-Co * T ³ * exp (-qEg / nKoT) * (exp (q (V + RsI) / nKoT) -1)-
(V + RsI) / Rsh where the symbols are as follows. I: Output current [A] Co: Saturation current temperature coefficient V: Output voltage [V] Eg: Energy gap [eV] IL: Photovoltaic current [A] T: Solar cell element absolute temperature [K] IO: Saturation current [ A] Ko: Boltzmann's constant [J / K] Rs: DC resistance [Ω] q: Electron charge [C] Rsh: Parallel resistance [Ω] n: Junction constant The above equation is theoretically based on the basic equation of semiconductor. It is a formula.
To find each point on the IV kerf from this equation, transfer I on the left side of this equation to the right side, and Func (V, I, IL, Co, n, Rsh, Rs, T) = IL-Co * T ³ * exp (-qEg / nKoT)
* (exp q (V + RsI) / nKoT-1)-(V + RsI) / Rsh-I and create a function of basic characteristic value (IL, Co, n, Rsh, Rs) , I is solved by a nonlinear solution program. See IEEJ paper 2 (Iga: "IV kerf preparation method using voltage-current characteristic equation in solar cell light irradiation state and its utilization", IEEJ D116, No. 10, 1996).

In the present invention, the characteristic values are properly used as follows. The basic characteristic value is a basic characteristic in the solar cell basic formula. (1) (Solar cell) basic characteristic value: IL, Co, n, Rsh, Rs (2) (Solar cell) characteristic value: Isc, Iop, Vop, Voc, α, β, Rs, K Rs is used in both (1) and (2).

The conversion formula is as follows. (1) `` Practical IV curve conversion formula '' I1 = I2 + Isc (E1 / (E2) -1) + α (t1-t2) V1 = V2 + β (t1-t2) -Rs (I1-I2)- K ・ I1 ・ (t1-t2) (2) Inverse conversion formula of “practical IV curve conversion formula” (application of reverse) (It is a modified version of V2 and I2 in (1) by solving the formula) I2 = I1 + Isc (E2-E1) / E2 + α (t2-t1) V2 = V1 + β (t2-t1) -Rs (I2-I1) -K ・ I1 ・ (t2-t1) 1) and (2) are commonly known JIS8913,891
Unlike the 4,8919 formula, it is a new and excellent formula. The equation (1) is used in Japanese Patent Application No. 6-2626 and the above-mentioned paper 1 of the Institute of Electrical Engineers of Japan (see FIG. 8). The symbols used in these equations are V2, I2, E2, and t2, respectively, for the voltage value, current value, solar radiation intensity, and solar cell temperature in the reference state. The voltage value, the current value, the solar radiation intensity, and the solar cell temperature in the designated state are defined as V1, I1, E1, and t1. Α: fluctuation value of Isc when temperature changes by 1 ° C. (A /
° C) β: Voc fluctuation when temperature changes by 1 ° C (V / ° C) Rs: Module series resistance (Ω) K: Curve correction factor (Ω) Isc: Short-circuit current Top: Optimal current Vop: Optimal voltage Voc: Release voltage. FIG. 8 shows a list of conversion equations of the voltage-current value in the reference state and the voltage-current value under the solar radiation intensity at measurement and the solar cell temperature condition. Equations (1) and (2) in the lower column of FIG. 8 correspond to “practical IV curve conversion equations”, and equations (3) and (4) in the right column of FIG.
It corresponds to the inverse conversion formula of "IV curve conversion formula". This figure is IEEJ paper 3 (Iga: "Solar cell pyranometer using a practical IV curve creation method", IEEJ, Vol. 117, No. 10, 1997)
The rightmost column and the lower column are the formulas of the author, and the lower column is a patent application filed in Japanese Patent Application No. 6-2626 before publication of a paper. In general, the formula in the leftmost or middle column may still be used. FIG. 6 shows a relationship between the voltage V and the current value I of the solar cell in a state of receiving sunlight. FIG.
As shown in the following, the voltage-current relationship curve is transformed into an IV curve (or
A voltage-power relationship curve called an IV curve is called a PV curve (or PV curve). The voltage (Vop) at the maximum power (Pmax) is called an optimum voltage, and the current (Iop) at that time is called an optimum current.

[0016]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 illustrates a “method of creating an IV curve of designated solar radiation intensity / solar cell temperature” which is a core part of power generation calculation in the solar power generation simulation calculation method of the present embodiment. In S11, the characteristic values (Isc, Io
p, Vop, Voc, α, β, Rs, K), and constants (Eg, Ko,
e), and in S13, the reference state of the solar cell (solar intensity 1k
w / m ² , solar cell temperature 25 ° C) (IL, Co,
n, Rsh) to the basic solar cell characteristic equation I = IL-Co * T ³ exp (-qEg / nKoT) * (exp (q (V + RsI) / nKoT) -1)-(V
+ RSI) / Rsh Determined by solving. That is, by substituting the characteristic values (Isc, Iop, Vop, Voc) given to the above basic characteristic expressions, four nonlinear simultaneous equations are created and solved. The calculated basic characteristic value is IL
Assuming that a, Coa, na, and Rsha, these basic characteristic values are again substituted into the solar cell basic characteristic expression in S14, and a relational expression between the voltage V and the current I is obtained. In this relational expression, the current I with respect to the voltage V is obtained by solving this characteristic expression, the relation of IV is obtained, and an IV curve in a reference state is created.

In step S15, by applying the “practical IV curve conversion formula” to each point on the IV curve created in step S14, the IV at the designated solar radiation intensity and designated solar cell temperature is obtained.
Find the curve (S19).

On the other hand, in S16, while the solar radiation intensity remains at 1 kw / m ² , an IV curve at a temperature b ° C. or c ° C. other than 25 ° C. is obtained by a “practical IV curve conversion formula”. S20 is b
The basic characteristic values IL, Co, n, Rsh, and Rs are obtained by solving the basic characteristic formula using the values of 5 to 8 points on the IV curve at ° C.
Ask for. In S21, the basic characteristic value at c ° C. is similarly obtained. In step S22, a basic characteristic value at the designated solar cell temperature is obtained from the respective basic characteristic values at 25 ° C, b ° C, and c ° C by curve interpolation.

The basic characteristic value at the specified voltage obtained here
IL adds solar intensity correction. In S23, the basic characteristic value obtained in this manner is applied to the solar cell basic characteristic formula to obtain the relationship between the voltage V and the current I, that is, an IV curve. FIG. 2 is a block diagram of the “photovoltaic power generation amount simulation calculation program” developed by the present inventor, which is already shown in the IEEJ Transactions 1. As described above, the core part of the present invention, "method of creating an IV curve at a specified solar radiation intensity and solar cell temperature," is a "solar cell output calculation subprogram".
Incorporated in

FIG. 3 and FIG. 4 illustrate the characteristic functions included in the “solar power generation amount simulation calculation program”.

FIG. 5 is a diagram of a data storage medium and a computer in which a "solar power generation amount simulation calculation program" including the present invention is recorded.

[0022]

According to the method of the first, second, third and fourth aspects, the following effects can be expected by a method of creating an IV curve at a specified solar radiation intensity and solar cell temperature and performing a simulation calculation of the amount of photovoltaic power generation. (1) In general, not only specific types and specific solar cells,
By inputting the characteristic values (Isc, Iop, Vop, Voc, Rs, α, β, K) of the solar cell, the monthly / annual power generation of the system using the solar cell can be accurately calculated. In other words, the amount of power generation can be calculated without being affected by the type of the solar cell to be applied, which is useful for designing and operating an effective solar power generation system. (2) By combining the above-mentioned “photovoltaic power generation simulation calculation program (IEEJ thesis 1)” and the present invention to form a system, it is possible to calculate power generation with higher accuracy and accuracy. The effect of the power generation simulation calculation becomes more effective. (3) In the simulation calculation of the amount of photovoltaic power generation, finer and more accurate calculation than the method of multiplying the calculated value of the amount of solar radiation on the light-receiving surface by the conversion efficiency to calculate the amount of power generation, which has been conventionally performed in most places. Because of this, deeper and more detailed analysis is possible. That is, detailed evaluation of the effect by the parameter becomes possible. (4) In the method of creating an IV curve at the specified solar radiation intensity and solar cell temperature and simulating and calculating the amount of photovoltaic power generation according to claims 1 and 3, the effects described in (1), (2) and (3) above are obtained. In addition, the characteristic values (Isc, Iop, Vop, Voc, α, β, R
s, K) are not available, that is, the reference temperature (2
IV curve and I at temperatures other than 5 ° C (eg 55 ° C)
If the values of sc, Iop, Vop, and Voc are obtained, calculation may be possible. In claim 5, I- according to claims 1, 2, 3, and 4
A program based on a method of calculating the amount of photovoltaic power generation, including a method of creating a V-curve, is stored in a recording medium, and is easily read and calculated by a computer when necessary. Therefore, it is widely useful for the design, construction and operation of photovoltaic power generation systems.

[Brief description of the drawings]

FIG. 1 is a block diagram of a method for creating an IV curve of designated solar radiation intensity and solar cell temperature.

FIG. 2 is a block diagram of a solar power generation amount simulation calculation program (developed already).

FIG. 3 is a flowchart for calculating the amount of solar radiation on the light receiving surface of a solar cell.

FIG. 4 is a diagram illustrating creation of an insolation curve by monthly average time.

FIG. 5 is a diagram of a data storage medium and a computer on which a solar power generation amount simulation calculation program is recorded.

FIG. 6 shows solar cell output characteristic curves (IV curve, PV curve).

FIG. 7 is a diagram of a mechanism of solar power generation.

FIG. 8 is a conversion equation of a voltage V-current value I at the time of measurement of solar irradiance and solar cell temperature to a reference state (IEEE's paper 3: “Solar cell pyranometer using a practical IV curve creation method, (Electronics D, Vol. 117, No. 10, 1997)

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Computer main body 2 Keyboard 3 Mouse 4 Monitor 5 Storage medium 17 Computer

Claims (5)

[Claims] [Claim 1] Basic solar cell formula I = IL-IO * {exp (q (V + RsI) / nKoT) -1}-(V + RsI) / Rsh IO = CoT ³ exp (-qEg / nKoT) Where, I: output current [A] Co: saturation current temperature coefficient V: output voltage [V] Eg: energy gap [eV] IL: photovoltaic current [A] T: solar cell element absolute temperature [K] IO: saturation Current [A] Ko: Boltzmann's constant [J / K] Rs: DC resistance [Ω] q: Electron charge [C] Rsh: Parallel resistance [Ω] n: Basic characteristic value (IL, Co, n) in junction constant , Rsh, Rs), the values of a ° C., b ° C., and c ° C. are obtained, and the respective values of a ° C., b
Calculate the respective basic characteristics (IL, Co, n, Rsh, Rs) at the specified temperature by interpolating the values at ℃ and c ℃, and again use the solar cell basic formula to specify the solar radiation intensity and the voltage at the solar cell temperature -A photovoltaic power generation system that creates a current curve (IV kerf), finds the power at the Pmax point or a specified voltage on this IV kerf, and integrates this monthly and yearly to determine the monthly and annual power generation. Quantity simulation calculation method. 2. A reference-state voltage-current curve is created from the characteristic values (Isc, Iop, Vop, Voc) of the solar cell, and the designated solar radiation intensity and designated solar radiation are calculated from the voltage-current curve using a solar radiation / temperature conversion formula. A voltage-current curve (IV curve) at battery temperature is created, the power at the Pmax point on this IV curve or at a specified voltage is determined, and this is integrated monthly and annually to determine the monthly and annual power generation. Solar power generation simulation calculation method. 3. {01} voltage V, current I, solar radiation intensity 1 kw / m ²
Current IL, saturation current temperature coefficient Co, junction constant n, parallel resistance Rsh, series resistance Rs, solar cell temperature T (absolute temperature)
Function: Func (V, I, IL, Co, n, Rsh, Rs, T) = IL-Co
T ³ exp (-qEg / nk0T) * (exp (q * (V + Rs * I) / (n * k0 * T)) -1)-
(V + Rs * I) / Rsh-I is created, and then {02} a function obtained by differentiating the function Func (V, I, IL, Co, n, Rsh, Rs, T) with the variable V: Dif (V, I, IL, Co, n, Rsh, Rs, T) and create {03} solar cell reference state (solar cell temperature Ta (298K (ta =
25 ° C)) and the solar radiation intensity Ea (1 kw / m ² )).
Short-circuit current Isca, optimal current Iopa-optimal voltage Vopa, open voltage Voca points P1 (0, Isca), P2 (Vopa, Iopa), P3 (Voca, 0) are selected, {04} the function Func (V, I, IL, Co, n, Rsh, Rs, T) = 0, the reference temperature Ta (298 K) at the solar cell temperature T, the value Rsa at the reference temperature at the series resistance Rs, and the P1, P2, P3. Substituting the value of the point and making IL, Co, n, Rsh an unknown.Relationship: Func (0, Isca, IL, Co, n, Rsh, Rsa, Ta) = 0, Relational equation: Func (Voca, 0 , IL, Co, n, Rsh, Rsa, Ta) = 0, relational expression: Func (Vopa, Iopa, IL, Co, n, Rsh, Rsa, Ta) = 0, and the function Dif ( V, I, IL, Co, n, Rsh, Rs, T) = 0, the reference state temperature Ta (298 K), the series resistance Rs and the reference temperature value R
sa, and the value of point P2 (Vopa, Iopa)
o, n, Rsh as unknowns, relational expression: Dif (Vopa, Iopa, IL, Co,
n, Rsh, Rsa, Ta) = 0, and then {06} the above four relational expressions: Func (0, Isca, IL, Co, n, Rsh, Rs
a, Ta) = 0, Func (Voca, 0, IL, Co, n, Rsh, Rsa, Ta) = 0, Func (V
opa, Iopa, IL, Co, n, Rsh, Rsa, Ta) = 0, Dif (Vopa, Iopa, IL, C
o, n, Rsh, Rsa, Ta) = 0 Solution A (ILa, Coa, na, Rsha)
Is calculated by a nonlinear solution program. Then, {07} the above function: Func (V, I, IL, Co, n, Rsh, Rs, T) = 0 IL,
Substituting the solution A (ILa, Coa, na, Rsha) into Co, n, Rsh,
Further, T represents the reference temperature Ta (298 K) and the series resistance Rs.
And the relational expression of the variables V and I: Func (V, I, ILa, Coa,
na, Rsha, Rsa, Ta) = 0 and {08}
Find the solution of I to V at ~ 50 points and calculate the voltage in the reference state.
(V)-current (I) and voltage (V)-power (P) (power (P) = voltage
(V) × current (I)) (approximately 40-50 points), and the voltage V-current I curve (IV curve) and voltage V-
A power P curve (PV curve) is created, and then {09} the solar radiation intensity Eb of the solar cell (here, 1 kw / m ² ),
In order to obtain the voltage Vb and the current Ib at the solar cell temperature Tb (absolute temperature: Tb (K) = tb (° C.) + 273), the solar radiation intensity Ea (1 kw / m ² ) in the reference state of the solar cell and the solar cell temperature Ta (298
K: absolute temperature: Ta = ta + 273), the short-circuit current Isca, the series resistance Rsa, the variation value α of the short-circuit current Isc when the temperature changes by 1 ° C., and the open-circuit voltage Voc when the temperature changes by 1 ° C.
Conversion factor (Va, Ia) → (Vb, Ib): Ib = Ia + α * (tb−ta) Vb = Va + β * (tb−ta) −Rsa * (Ib-Ia)-K * Ib * (tb
-ta), and each of the voltage-current points created in {08} or each point on the IV curve connecting them is represented by Ia, V
Used as a value, solar radiation intensity Eb (here 1 kw / m ² ), each point in solar cell temperature Tb (K) (voltage Vb-current Ib: about 40-50 points)
, And create an IV curve and a PV curve connecting these points. Then, select any five non-close points from the IV curve created in {10} above {09}, and select these points ( VQ1, IQ1), (VQ2, I
Q2), (VQ3, IQ3), (VQ4, IQ4), (VQ5, IQ5)
c (V, I, IL, Co, n, Rsh, Rs, Tb) = 0
Let IL, Co, n, Rsh, Rs be unknown.Relationship: Func (VQ1, IQ1, IL, Co, n, Rsh, Rs, Tb) = 0, Relationship: Func (VQ2, IQ2, IL, Co , n, Rsh, Rs, Tb) = 0, Relationship: Func (VQ3, IQ3, IL, Co, n, Rsh, Rs, Tb) = 0, Relationship: Func (VQ4, IQ4, IL, Co, n , Rsh, Rs, Tb) = 0, and a relational expression: Func (VQ5, IQ5, IL, Co, n, Rsh, Rs, Tb) = 0 is created, and a solution B (ILb, Cob, nb, Rshb, Rsb) is calculated by a nonlinear solution program, and then {11} the solar radiation intensity Ec of the solar cell (here, 1 kw / m ² ),
The relationship between the voltage Vc and the current Ic at the solar cell temperature Tc (absolute temperature: Tc (K) = tc (° C.) + 273) is also obtained in the same manner as in the above {09}, by the conversion equation (Va, Ia) → (Vc, Ic). : Ic = Ia + α * (tc-ta) Vc = Va + β * (tc-ta)-Rsa * (Ic-Ia)-K * Ic * (tc
-ta) to create an IV curve and a PV curve, and select any five points that are not close to each other from the IV curve created in {12} above {11}, and these values (VR1, IR1), (VR2, IR
2), (VR3, IR3), (VR4, IR4), (VR5, IR5)
(V, I, IL, Co, n, Rsh, Rs, Tc) = 0
Let Co, n, Rsh, Rs be unknown.Relational expression: Func (VR1, IR1, IL, Co, n, Rsh, Rs, Tc) = 0, Relational expression: Func (VR2, IR2, IL, Co, n , Rsh, Rs, Tc) = 0, Relational expression: Func (VR3, IR3, IL, Co, n, Rsh, Rs, Tc) = 0, Relational expression: Func (VR4, IR4, IL, Co, n, Rsh , Rs, Tc) = 0, and a relational expression: Func (VR5, IR5, IL, Co, n, Rsh, Rs, Tc) = 0 is created, and the solution C (ILc, Coc, nc, Rshc, Rsc)
Is calculated by a nonlinear solving program. Then, the solar radiation intensity Em and the solar cell temperature tm specified at {13} (that is, at each time each month) are taken in, and the temperature ta (Celsius) in the {14} reference state is obtained. 25 ° C: Absolute temperature Ta
(K) = ta (° C.) + 273), the solution A (ILa, Coa,
na, Rsha), the solution B (ILb, Cob, nb, Rshb, Rsb) of the {10} at the temperature tb (° C .: Tb (K) = tb (° C.) + 273), and the temperature tc
(Celsius: Tc = tc + 273), the solution C (ILc, Coc,
nc, Rshc, Rsc) and input value Rsa (IL, Co, n, Rs
h, Rs), the curve is interpolated at three points and the specified temperature tm
Then, the characteristic value M (ILm, Com, nm, Rshm, Rsm) is calculated, and then, ｛15｝ ILm is set to IL ^′ m = ILm × E by the designated solar radiation intensity Em.
After correcting by m ÷ Ea (Ea = 1 (KW / m ² )), the relational expression: F
unc (V, I, IL, Co, n, Rsh, Rs, T) = 0 when IL ^′ m, Com, nm, Rshm, Rsm
And Func (V, I, IL ^′ m, Com, nm, Rshm, Rsm, Tm) = 0
The voltage (V) -current (I) relationship (approximately 40-50 points) is obtained by a nonlinear solution program, and the voltage (V) -current (I) relationship or the IV curve, PV A curve is created, and the power at the Pmax point on this IV kerf or the power at the voltage specified as a parameter is found, and this value is used as the power value for each month and time, and the monthly and yearly power is accumulated. A method for calculating a simulation of the amount of photovoltaic power generation, characterized in that the amount is calculated. 4. A reference state (insolation intensity of 1 kW / infrared light) designated by {20} (ie, at each time of each month) and the solar cell temperature tm taken in {21} above {01} to {08}. m ² , solar cell temperature 25 ° C)
Regarding the current Ia value (about 40 to 50 points),
Using ca, α, β, Rsa, k, conversion formula (Va, Ia) → (Vk, Ik): Ik = Ia + Isca * (Em / Ea-1) + α * (tm-ta) Vk = Va + β * (tm-ta)-Rsa * (Ik-Ia)-K * Ik * (tm
-ta), convert these voltage V-current I value or IV curve and PV curve connecting them, and {22} power of Pmax point on this IV kerf or power at voltage specified as parameter And calculating this value as the power value for each time of each month, and calculating the monthly / annual power generation amount by monthly / yearly integration. 5. A computer-readable data storage medium on which a processing program of the method for calculating the amount of photovoltaic power generation simulation according to claim 1, 2, 3, or 4 is recorded.