JP2012015199A - Predicted electric power generation amount calculating device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide predicted electric power generation amount calculating device and method that can predict an electric power generation amount of each constituent component of a solar battery string.SOLUTION: A solar battery array is constructed by electrically connecting solar battery strings in parallel, and each of the solar battery strings generates electric power by receiving sunlight and is constructed by electrically connecting solar battery string constituent elements in series. A predicted power generation amount calculating device 1 for calculating a predicted power generation amount of the solar battery string constituent component for the solar battery array has a solar radiation intensity receiver 2 for receiving a solar radiation intensity, array voltage calculating means for calculating a voltage at the time when the maximum power generation amount of the solar battery array is achieved, string current calculating means for calculating current of the solar battery string, predicted voltage calculating means for calculating a predicted voltage of the solar battery string constituent component, and predicted power generation amount calculating means for calculating the predicted power generation amount of the solar battery string constituent component.

Description

  The present invention relates to a predicted power generation amount calculation device and a predicted power generation amount calculation method for a solar cell.

  In general, a solar cell array is configured by connecting a plurality or a single solar cell string in parallel, and the solar cell strings in the same array are often connected via a backflow prevention diode. ing. A solar cell string is obtained by connecting one or more solar cell modules in series, and one solar cell module is formed by connecting one or more solar cell clusters in series. A solar battery cluster is configured by connecting a single bypass diode in parallel to a plurality of solar battery cells connected in series with each other.

  Therefore, for example, a solar cell module configured by three clusters has a configuration as shown in FIG. In FIG. 13, black squares indicate solar cells, and here, a case where 10 cells are included in one cluster is shown. Hereinafter, the solar cell string component means a solar cell cluster (or solar cell). Generally, a solar cell cluster is used as a solar cell string component, but when calculating the power generation amount of a solar cell array using a solar cell module without a bypass diode, as a solar cell string component, It is necessary to use solar cells.

  Conventionally, a method for obtaining a maximum output value of the entire solar cell array under a situation during power generation of the solar cell array is known. For example, in patent document 1, in the solar cell array comprised from the string of solar cell clusters, the rated value of the output current and output voltage of each solar cell cluster, the solar radiation intensity and temperature of each solar cell cluster, and the solar cell cluster A method for obtaining the maximum output value of the entire solar cell array on the basis of the string arrangement pattern is disclosed.

  Here, the current and voltage that can be output from the solar cell indicate the maximum current (short-circuit current) when the solar cell is short-circuited, that is, the output voltage is 0 V, and the maximum voltage (open-circuit voltage) when the solar cell is opened. In this case, the current becomes zero. When the load resistance connected to the solar cell is changed, the current and voltage that can be output from the solar cell are connected between the two points and traced on the curve representing the current-voltage relationship of the solar cell, ie, the IV curve. Change. Therefore, the output current and voltage of the solar cell are characterized and described by the IV curve.

  Patent Document 1 discloses a method of displaying a current and a voltage that can be output by a solar cell, that is, an IV curve by approximating them by rectangular superposition without performing complicated calculations. Patent Document 1 discloses a method of displaying an approximate IV curve of a whole solar cell array by overlapping rectangles.

JP 2007-3390 A

  However, Patent Document 1 does not disclose a method for obtaining the power generation amount of each solar cell string component during power generation of the solar cell array. If the power generation amount of each solar cell string component is not required, it is unclear how much each solar cell string component contributes to power generation, and appropriate evaluation such as optimal arrangement of each solar cell string component is possible. There is a problem that it is difficult.

  Therefore, the present invention has been made to solve the above problems, and an object thereof is to provide a predicted power generation amount calculation device and a predicted power generation amount calculation method capable of predicting the power generation amount of each solar cell string component. .

  In order to solve the above-described problem, the predicted power generation amount calculation apparatus of the present invention electrically connects a solar cell string configured by electrically connecting solar cell string components that receive sunlight and generate power, in series. A predicted power generation amount calculation device for calculating a predicted power generation amount of a solar cell string component for a solar cell array configured to be connected in parallel, the solar radiation intensity receiving unit receiving solar radiation intensity of the solar cell string component; The array voltage calculating means for calculating the array voltage, which is the voltage of the solar cell array when the maximum power generation amount of the solar battery array is obtained based on the solar radiation intensity received by the solar radiation intensity receiving means, and the array voltage calculating means String current calculating means for calculating a string current that is a current of the solar cell string at the calculated array voltage, and the string Based on a predicted voltage calculation means for calculating a predicted voltage, which is a predicted voltage of the solar cell string component in the flow, a string current calculated by the string current calculation means, and a predicted voltage calculated by the predicted voltage calculation means And a predicted power generation amount calculating means for calculating a predicted power generation amount of the solar cell string constituent elements.

  Moreover, the predicted power generation amount calculation method of the present invention includes a solar cell string that is configured by electrically connecting solar cell string components that receive sunlight to generate electric power in series, and is electrically connected in parallel. For the solar cell array to be configured, the predicted power generation amount calculation device for calculating the predicted power generation amount of the solar cell string component receives the solar radiation intensity reception step for receiving the solar radiation intensity of the solar cell string component, and the predicted power generation amount calculation device. An array voltage calculation step for calculating an array voltage that is a voltage of the solar cell array when the maximum power generation amount of the solar cell array is obtained based on the solar radiation intensity received in the solar radiation intensity reception step, and a predicted power generation amount calculation device Calculates a string current that is a current of the solar cell string at the array voltage calculated in the array voltage calculation step. A tring current calculation step, a predicted power generation amount calculation device that calculates a predicted voltage that is a predicted voltage of a solar cell string component in a string current, and a predicted power generation amount calculation device includes a string current calculation step. A predicted power generation amount calculating step of calculating a predicted power generation amount of the solar cell string constituent element based on the string current calculated in step (b) and the predicted voltage calculated in the predicted voltage calculation step.

  According to the present invention, the array voltage is calculated based on the received solar radiation intensity, and the string current at the calculated array voltage is calculated. In addition, a predicted voltage in the calculated string current is calculated, and a predicted power generation amount of the solar cell string constituent element is calculated based on the calculated string current and the calculated predicted voltage. That is, in the solar cell array that generates power by receiving sunlight based on solar radiation intensity at the solar cell string component, the predicted power generation amount for each solar cell string component can be calculated. Thereby, it becomes clear how much each solar cell string component contributes to power generation at the time of power generation of the solar cell array, and appropriate evaluation of each solar cell string component can be performed.

  Further, in the predicted power generation amount calculation device of the present invention, the array voltage calculation means calculates and calculates the current and voltage that can be output by the solar cell string component based on the solar radiation intensity received by the solar radiation intensity receiving means. Based on the current and voltage that can be output by the solar cell string components, the current and voltage that can be output by the solar cell string are calculated, and based on the current and voltage that can be output by the calculated solar cell string, the solar cell The current and voltage that can be output by the array are calculated, the array voltage is specified based on the calculated current and voltage that can be output by the solar cell array, and the string current calculation means is the solar current calculated by the array voltage calculation means. Based on the current and voltage that the battery string can output and the array voltage calculated by the array voltage calculation means, Preferably, the predicted voltage calculating means calculates the predicted voltage based on the maximum voltage that can be output by the solar cell string constituent element calculated by the array voltage calculating means and the array voltage. is there.

  According to the present invention, the current and voltage that can be output by the solar cell string component are calculated based on the received solar radiation intensity, and the calculated current and voltage that can be output by the solar cell string component are obtained. Based on this, the current and voltage that can be output by the solar cell string are calculated. Further, based on the current and voltage that can be output by the calculated solar cell string, the current and voltage that can be output by the solar cell array are calculated, and based on the current and voltage that can be output by the calculated solar cell array, Specify the array voltage. Furthermore, the string current is specified based on the calculated current and voltage that can be output from the solar cell string and the calculated array voltage, and the solar cell string component can be output based on the specified string current. The maximum voltage is calculated, and the predicted voltage is calculated based on the maximum voltage that can be output by the calculated solar cell string component and the array voltage. Furthermore, the predicted power generation amount of the solar cell string component can be calculated based on the calculated predicted voltage of the solar cell string component and the string current. That is, the predicted power generation amount of the solar cell string component can be calculated in the solar cell array that generates power by receiving sunlight based on solar radiation intensity at the solar cell string component. Thereby, it becomes clear how much each solar cell string component contributes to power generation at the time of power generation of the solar cell array, and appropriate evaluation of each solar cell string component can be performed.

  Further, in the predicted power generation amount calculation device of the present invention, the predicted voltage calculation means uses the string element that is the voltage of the solar cell string component as the maximum voltage that can be output by the solar cell string component calculated by the array voltage calculation means. The string maximum voltage, which is the maximum voltage of the solar cell string in the string current, is calculated based on the string element maximum voltage as the maximum voltage, and the array voltage calculated by the array voltage calculation unit is calculated with respect to the string element maximum voltage. It is also preferable to calculate the predicted voltage by multiplying the voltage maintenance ratio that is a ratio to the calculated maximum string voltage.

  According to the present invention as described above, the maximum voltage that can be output by the calculated solar cell string component is the string element maximum voltage that is the voltage of the solar cell string component, and the string maximum voltage is based on the string element maximum voltage. Is calculated. Also, the predicted voltage is calculated by multiplying the string element maximum voltage by a voltage maintenance ratio that is a ratio of the calculated array voltage to the calculated string maximum voltage.

  In general, when the voltage of each solar cell string component in the solar cell string is obtained from the current of the solar cell string, the voltage of the solar cell string component changes greatly with a slight change in the current of the solar cell string. It may be difficult to make a decision. This phenomenon is seen when the voltage of the solar cell array is below the voltage that can be generated by the solar cell string. Therefore, the present invention can predict the voltage of the solar cell string component by using the voltage maintenance rate. In practice, due to slight non-uniformity of solar radiation between solar cells, etc., the voltage burden ratio between each solar cell string component may differ from the voltage predicted using the voltage maintenance rate, This approximation makes it possible to allocate the power generation amount of the solar cell array to each solar cell string component.

  Further, in the predicted power generation amount calculation device of the present invention, the array voltage calculation means calculates the current and voltage that can be output from the solar cell string component based on the solar radiation intensity received by the solar radiation intensity receiving means. Based on the current and voltage that can be output from the solar cell string component, the current and voltage that can be output from the solar cell string are calculated, and based on the calculated current and voltage that can be output from the solar cell string, A current and voltage that can be output from the array are calculated, and an array voltage is calculated based on the calculated current and voltage that can be output from the solar cell array. Based on the current and voltage that can be output from the battery string and the array voltage calculated by the array voltage calculation means, The predicted voltage calculating means calculates the predicted current based on the current and voltage that can be output from the solar cell string component calculated by the array voltage calculating means and the string current calculated by the string current calculating means. It is also preferable to calculate the voltage.

  According to the present invention, the current and voltage that can be output from the solar cell string component are calculated based on the received solar radiation intensity, and the current and voltage that can be output from the solar cell string component are calculated. Based on this, an outputable current and voltage of the solar cell string are calculated. Further, based on the current and voltage that can be output from the calculated solar cell string, the current and voltage that can be output from the solar cell array are calculated, and based on the current and voltage that can be output from the calculated solar cell array, Calculate the array voltage. Further, a string current is calculated based on the calculated output current and voltage of the solar cell string and the calculated array voltage, and is calculated as an output current and voltage of the calculated solar cell string component. The predicted voltage of the solar cell string component is calculated based on the string current. That is, the predicted power generation amount of the solar cell string component can be calculated in the solar cell array that generates power by receiving sunlight based on solar radiation intensity at the solar cell string component. Thereby, it becomes clear how much each solar cell string component contributes to power generation at the time of power generation of the solar cell array, and appropriate evaluation of each solar cell string component can be performed.

  Further, in the predicted power generation amount calculation device of the present invention, the state of the solar cell string constituent elements constituting the solar cell array is displayed so as to correspond to the physical position of the solar cell string constituent elements in the actual solar cell array. It is also preferable that the display unit further displays a numerical value or a figure based on the predicted power generation amount of the solar cell string component calculated by the predicted power generation amount calculation unit as the state of the solar cell string component. It is.

  According to the present invention, the state of the solar cell string component constituting the solar cell array is displayed so as to correspond to the physical position of the solar cell string component in the actual solar cell array, A numerical value or a figure based on the calculated predicted power generation amount of the solar cell string component can be displayed as the state of the solar cell string component. As a result, it is possible to display how much the solar cell string components contribute to power generation for the installed or planned solar cell array, and determine the appropriateness of the arrangement of the solar cell string components. can do. For example, when there is a possibility that the amount of power generation is reduced due to the shadow of an obstacle such as a utility pole, it is effective to calculate and compare the power generation amount of each solar cell string component when there is no shadow. . By this comparison, it is possible to evaluate a decrease in the amount of power generation due to the shadow.

  In the predicted power generation amount calculation device of the present invention, the display means uses the numerical value or the figure based on the solar radiation intensity received by the solar radiation intensity receiving means as the state of the solar cell string constituent element, and the predicted power generation amount of the solar cell string constituent element. It is also preferable to display together with a numerical value or a figure based on.

  According to such this invention, the numerical value or figure based on the received solar radiation intensity is displayed as a state of the said solar cell string component. Thereby, about the solar cell array installed or to be installed, the state based on the solar radiation intensity can be displayed together with the state based on the predicted power generation amount of the solar cell string component. By comparing the two, for example, the solar cell string component whose power generation amount is reduced due to the direct influence of the shadow, and the shadow of other solar cell string components that are not themselves shadowed, Thus, it is possible to separate the solar cell string constituent elements whose power generation amount is reduced. If there are many solar cell string components whose power generation has been reduced due to the direct influence of shadows, the installation of solar cells in the shadowed area is the cause of the decrease in power generation. It is necessary to review the installation location. On the other hand, if there are many solar cell string components that are not shaded but are affected by the shadows of other solar cell string components and the amount of power generation is reduced, the connection of solar cells can be optimized, There is a possibility that the amount of power generation can be recovered by using a small converter or small inverter corresponding to a small solar cell. Furthermore, the optimization of connection, the use of a small converter, and a small inverter have the advantage that the amount of power generation can be recovered by a simple facility modification even in an already installed solar power generation system. That is, the present invention can be used not only for designing as a preparation for system installation but also for diagnosing and improving an installed system.

  According to the present invention, it is possible to provide a predicted power generation amount calculation device and a predicted power generation amount calculation method capable of predicting the power generation amount of each solar cell string component.

It is a functional block diagram which shows the function of the prediction electric power generation amount calculation apparatus of this embodiment. It is a hardware block diagram of the prediction electric power generation amount calculation apparatus of this embodiment. It is a block diagram of the solar cell array of this embodiment. It is the figure which modeled the rectangular IV curve of the solar cell cluster of this embodiment (the 1). It is the figure which modeled the rectangular IV curve of the solar cell cluster of this embodiment (the 2). It is the figure which modeled the rectangular IV curve of the solar cell cluster of this embodiment (the 3). It is the figure which showed the continuous IV curve of the solar cell cluster of this embodiment (the 1). It is the figure which showed the continuous IV curve of the solar cell cluster of this embodiment (the 2). It is the figure which showed the continuous IV curve and continuous PV curve of the solar cell array of this embodiment. It is a figure which shows the solar radiation condition and power generation condition of a solar cell cluster displayed by the prediction power generation amount calculation apparatus of this embodiment (the 1). It is a figure which shows the solar radiation condition and power generation condition of a solar cell cluster displayed by the prediction power generation amount calculation apparatus of this embodiment (the 2). It is a flowchart figure which shows the process of the prediction electric power generation amount calculation apparatus of this embodiment. It is a figure which shows an example of a structure of a solar cell module.

  Hereinafter, preferred embodiments of a predicted power generation amount calculation apparatus and a predicted power generation amount calculation method according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a functional block diagram showing the configuration of the predicted power generation amount calculation device 1 of the present embodiment. As shown in FIG. 1, the predicted power generation amount calculation device 1 includes a solar radiation intensity receiving unit 2 (a solar radiation intensity receiving unit), an array voltage calculating unit 3 (an array voltage calculating unit), and a string current calculating unit 4 ( A string current calculating unit), a predicted voltage calculating unit 5 (predicted voltage calculating unit), a predicted power generation amount calculating unit 6 (predicted power generation amount calculating unit), and a display unit 7 (display unit).

  As shown in FIG. 1, the array voltage calculation unit 3 includes a solar cell array voltage calculation function 3a, a solar cell array IV curve calculation function 3b, a solar cell string IV curve calculation function 3c, and a solar cell string component continuous IV. The curve calculation function 3d (or the solar cell string component rectangle IV curve calculation function 3e) is included.

  The predicted power generation amount calculation device 1 is configured by hardware such as a CPU. FIG. 2 is a hardware configuration diagram of the predicted power generation amount calculation apparatus 1. As shown in FIG. 2, the predicted power generation amount calculation apparatus 1 shown in FIG. 1 physically includes a CPU 51, a RAM 52 and a ROM 53 that are main storage devices, an input device 54 such as a numeric keypad that is an input device, a display, and the like. The computer system includes an output device 55, a communication module 56 that is a data transmission / reception device, and an auxiliary storage device 57 such as a hard disk. The functions of the functional blocks shown in FIG. 1 are such that predetermined computer software is loaded on hardware such as the CPU 51 and the RAM 52 shown in FIG. 2 to control the input device 54, the output device 55, and the communication under the control of the CPU 51. This is realized by operating the module 56 and reading and writing data in the RAM 52 and the auxiliary storage device 57.

  Hereinafter, each functional block of the predicted power generation amount calculation device 1 will be described based on the functional blocks shown in FIG. The predicted power generation amount calculation device 1 is a solar cell that is configured by electrically connecting solar cell strings that are configured by electrically connecting solar cell string components that receive sunlight to generate electric power in series. For the battery array, the predicted power generation amount of the solar cell string component is calculated.

  FIG. 3 is a diagram showing an example of the configuration of the solar cell array. In FIG. 3, the solar cell array AR1 is configured by electrically connecting a solar cell string ST1 and a solar cell string ST2 in parallel. Solar cell string ST1 is configured by electrically connecting solar cell module MD11 and solar cell module MD12 in series. Similarly, the solar cell string ST2 includes a solar cell module MD21 and a solar cell module MD22 that are electrically connected in series.

  The solar cell module MD11 is configured by electrically connecting a solar cell cluster CL11 and a solar cell cluster CL12 in series. Similarly, the solar cell module MD12 is configured by electrically connecting a solar cell cluster CL13 and a solar cell cluster CL14 in series. Similarly, the solar cell module MD21 is configured by electrically connecting a solar cell cluster CL21 and a solar cell cluster CL22 in series. Similarly, the solar cell module MD22 is configured by connecting a solar cell cluster CL23 and a solar cell cluster CL24 electrically in series.

  Note that the solar cell string ST1 can also be regarded as a configuration in which the solar cell cluster CL11, the solar cell cluster CL12, the solar cell cluster CL13, and the solar cell cluster CL14 are electrically connected in series. Similarly, the solar cell string ST2 can also be regarded as a configuration in which the solar cell cluster CL21, the solar cell cluster CL22, the solar cell cluster CL23, and the solar cell cluster CL24 are electrically connected in series.

  The solar radiation intensity receiving unit 2 receives the solar radiation intensity of each of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 that are solar cell string components from an external terminal. In the present embodiment, the form in which the solar radiation intensity is received from an external terminal will be described below. However, the solar radiation intensity may be input by an input unit, or may be stored in advance in a storage unit.

  Based on the solar radiation intensity received by the solar radiation intensity receiver 2, the array voltage calculator 3 calculates an array voltage that is a voltage of the solar battery array AR1 when the maximum amount of power generation of the solar battery array AR1 is obtained. Moreover, the array voltage calculation part 3 is based on the solar radiation intensity received by the solar radiation intensity receiving part 2, and the current and voltage which can be output by the solar battery clusters CL11-14 and the solar battery clusters CL21-24 (solar battery string configuration) Element IV curve), and based on the calculated IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24, currents and voltages that can be output by the solar cell string ST1 and the solar cell string ST2 ( (IV curve of solar cell string) is calculated, and based on the calculated IV curves of solar cell string ST1 and solar cell string ST2, the current and voltage (IV curve of solar cell array) that can be output by solar cell array AR1 are calculated. And based on the calculated IV curve of the solar cell array AR1 The array voltage may be identified.

  The string current calculation unit 4 calculates a string current that is a current of the solar cell string ST1 and the solar cell string ST2 at the array voltage calculated by the array voltage calculation unit 3. Further, the string current calculation unit 4 is based on the IV curve of the solar cell string ST1 and the solar cell string ST2 calculated by the array voltage calculation unit 3 and the array voltage calculated by the array voltage calculation unit 3. May be specified.

  The predicted voltage calculation unit 5 calculates a predicted voltage that is a predicted voltage of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 in the string current. Further, the predicted voltage calculation unit 5 calculates the predicted voltage based on the array voltage and the maximum voltage that can be output by the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 calculated by the array voltage calculation unit 3. It may be calculated. In addition, the predicted voltage calculation unit 5 calculates the maximum voltage that can be output from the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 calculated by the array voltage calculation unit 3, and the solar cell clusters CL11 to 14 and solar cells. The string element maximum voltage that is the voltage of the clusters CL21 to 24 is used, and the string maximum voltage that is the maximum voltage of the solar cell string ST1 and the solar cell string ST2 in the string current is calculated based on the string element maximum voltage. The predicted voltage may be calculated by multiplying the array voltage calculated by the array voltage calculation unit 3 by a voltage maintenance ratio that is a ratio of the calculated string maximum voltage.

  The predicted voltage calculation means is calculated by the array voltage calculation means and the current and voltage that can be output by the solar cell string component calculated by the array voltage calculation means, the string current calculated by the string current calculation means, and the array voltage calculation means. The predicted voltage of the solar cell string component may be calculated based on the array voltage. In addition, the predicted voltage calculation unit 5 is a solar cell cluster that is calculated from the current and voltage that can be output by the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 calculated by the array voltage calculation unit 3, and the string current. The maximum voltage that can be output from the CL 11 to 14 and the solar cell clusters CL 21 to 24 is set as the string element maximum voltage, and the maximum voltage that can be output from the solar cell string ST1 and the solar cell string ST2 in the string current based on the string element maximum voltage. The string maximum voltage is calculated, and the predicted voltage is calculated by multiplying the string element maximum voltage by the voltage maintenance ratio that is the ratio of the array voltage calculated by the array voltage calculation unit 3 to the calculated string maximum voltage. May be calculated.

  Further, the predicted voltage calculation unit 5 uses the string current calculated by the string current calculation unit 4 and the solar cell string component continuous IV curve calculated by the solar cell string component continuous IV curve calculation function 3d described later. The predicted voltage of the solar cell string component may be calculated. The predicted voltage calculation unit 5 includes a string current calculated by the string current calculation unit 4, a solar cell string component rectangle IV curve calculated by a solar cell string component rectangle IV curve calculation function 3e described below, The predicted voltage of the solar cell string constituent element may be calculated from the array voltage calculated by the array voltage calculation unit 3.

  The predicted power generation amount calculating unit 6 is based on the string current calculated by the string current calculating unit 4 and the predicted voltage calculated by the predicted voltage calculating unit 5, and the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to CL21. 24 predicted power generation amounts are calculated.

  Next, each function included in the array voltage calculation unit 3 will be described. The solar cell array voltage calculation function 3a is a function for calculating a voltage when the generated power of the solar cell array becomes maximum. The solar cell array voltage calculation function 3a calculates a voltage when the generated power of the solar cell array becomes maximum from the relationship between the current and voltage output by the solar cell array (that is, the IV curve of the solar cell array).

  The solar cell array IV curve calculation function 3b is a function for calculating the relationship between the current and voltage output by the solar cell array (that is, the IV curve of the solar cell array). The solar cell array IV curve calculation function 3b adds the relationship between the current and voltage output by the solar cell string calculated by the solar cell string IV curve calculation function 3c (that is, the IV curve of the solar cell string) in the current direction. Thus, the IV curve of the solar cell array is calculated. However, in this case, in the case of a system provided with a backflow prevention diode in the solar cell string, in consideration of the effect of the backflow prevention diode, the solar cell array IV curve calculation function at a voltage at which the current of the solar cell string is negative. In 3b, it is necessary to add the current of the solar cell string as 0.

  The solar cell string IV curve calculation function 3c is a function for calculating the relationship between the current and voltage output by the solar cell string (that is, the IV curve of the solar cell string). The solar cell string IV curve calculation function 3c includes a current output by the solar cell string component calculated by the solar cell string component continuous IV curve calculation function 3d (or the solar cell string component rectangular IV curve calculation function 3e), and The IV curve of the solar cell string is calculated by adding the voltage relationship (that is, the IV curve of the solar cell string component) in the voltage direction. However, at this time, since the solar cell string component includes a bypass diode, in the current where the voltage of the solar cell string component is negative, the voltage of the solar cell string component is set to 0 or a minute voltage generated by the bypass diode. According to the drop, it is necessary to add as a negative value of about −2V to −0.5V. Actually, in such a current, the solar cell string IV curve calculation function 3c is preferably performed by adding the voltage as zero.

The relationship between the current and voltage output by the solar cell string component (IV curve) can be obtained from the following parameters.
Solar cell rating 1 (required)
Maximum output operating point current (Ipm0) under standard conditions (irradiance 1 kW / m ² , solar cell temperature 25 ° C.)
Maximum output operating point voltage (Vpm0) in standard condition
Solar cell rating 2 (optional)
Short-circuit current in standard state (Isc0)
Open-circuit voltage in the standard state (Voc0)
These two are necessary when calculating a continuous IV curve.
Temperature dependence of solar cell voltage (β (% / ° C))
This is necessary when considering voltage changes due to temperature changes in solar cells.
Temperature dependence of solar cell current (α (% / ° C))
This is necessary when considering current changes due to temperature changes in solar cells.
Situation 1 where solar cells are placed (required)
Solar radiation intensity Situation 2 where solar cells are placed (optional)
Solar cell temperature This is necessary when considering changes in voltage or current due to changes in solar cell temperature.

Although most of the above parameters can be substituted by the corresponding parameters of the solar cell module, for the two of Vpm0 and Voc0, the corresponding parameters of the solar cell module are the solar cell cluster configuration included in the solar cell module. It is necessary to find by dividing by the number of elements. Here, the standard state refers to a state in which the solar radiation intensity is 1 kW / m ² and the solar cell temperature is 25 ° C.

  Among the above parameters, Ipm0, Vpm0, Isc0, Voc0, α, β may be obtained from an external terminal via the communication module 56 as given data specific to the solar cell used, or an input device 54 may be used for input, or may be stored in the ROM 53. On the other hand, among the above parameters, “solar radiation intensity” means the radiant energy intensity of the sun irradiated to each solar cell cluster. In the present embodiment, the solar radiation intensity receiving unit 2 is described as receiving solar radiation energy intensity irradiated to individual solar cell clusters. However, the solar radiation intensity receiving unit 2 receives solar radiation data of each region unit, It is good also as a structure which calculates the solar radiation intensity of each solar cell cluster from the position of a solar cell cluster, a normal line direction, the spatial arrangement | positioning of the object which makes a shadow, etc. The temperature of the solar cell can be actually measured, but it is preferable to calculate it according to an empirical rule from the temperature, solar radiation intensity, etc., and input it to the calculating means of the present invention.

  The IV curve of the solar cell string constituent element can be obtained by solving a characteristic equation derived from an equivalent circuit of the solar cell. The IV curve obtained by this method is referred to as “continuous IV curve” in the present invention.

  The solar cell string component continuous IV curve calculation function 3d is a function of calculating the IV curve of the solar cell string component at the actual solar radiation intensity and solar cell temperature as a continuous IV curve. A method for obtaining a continuous IV curve of a solar cell component by the solar cell string component continuous IV curve calculation function 3d will be exemplified below.

  First, the solar cell string component continuous IV curve calculation function 3d includes Isc0 which is a short-circuit current in the standard state of the solar cell component, Voc0 which is an open voltage in the standard state of the solar cell component, and a standard state of the solar cell component The continuous IV curve in the standard state of the solar cell component is determined from the four of the maximum output operating point current (Ipm0) and the maximum output operating point voltage (Vpm0) in the standard state of the solar cell component. Next, the solar cell string component continuous IV curve calculation function 3d multiplies the voltage of the continuous IV curve in the standard state by (1 + β × Δ), where Δ (° C.) is an increase in solar cell temperature from 25 ° C. Obtain a continuous IV curve after temperature-voltage correction (however, since β is normally a negative value, it is usually multiplied by (1− | β | × Δ)). Subsequently, the solar cell string component continuous IV curve calculation function 3d multiplies the current of the continuous IV curve after temperature-voltage correction by (1 + α × Δ) to obtain a continuous IV curve after temperature correction. However, the correction by α is usually not so large and can be omitted.

Finally, the solar cell string component continuous IV curve calculation function 3d performs correction based on solar radiation intensity as follows. That is, the solar cell string component continuous IV curve calculation function 3d obtains a continuous IV curve after correcting the solar radiation intensity by multiplying a parameter iph described later by x and not changing the other three parameters. Can do. Alternatively, the solar cell string component continuous IV curve calculation function 3d calculates Isc0 × (1−x) × (1 + α × Δ) from the current of the continuous IV curve after temperature correction, where the solar radiation intensity is x (kW / m ² ). ), The IV curve of the solar cell string component can also be determined as a continuous IV curve.

  When the IV curve of the solar cell constituent element is obtained as a continuous IV curve, the solar cell string IV curve calculation function 3c is used to obtain the continuous IV curve of the solar cell string based on the obtained IV curve. The IV curve calculation function 3b makes it possible to obtain a continuous IV curve of the solar cell array.

  On the other hand, it is also preferable to obtain the IV curve of the solar cell string constituent element by approximating it with a rectangle. The IV curve obtained by this method is referred to as “rectangular IV curve” in the present invention.

  The solar cell string component rectangle IV curve calculation function 3e is a function for calculating the IV curve of the solar cell string component as a rectangular IV curve. A method for obtaining the rectangular IV curve of the solar cell string component by the solar cell string component rectangular IV curve calculation function 3e will be described below. This method is based on the method disclosed in the patent document (Japanese Patent Laid-Open No. 2007-3390).

The rectangular IV curve is a method of approximating the IV curve by dividing the voltage into a finite number of voltage ranges and making one current correspond to each voltage range. Specifically, the IV curve is expressed as follows.
In the range of 0 <voltage ≦ V1, current = I1
In the range of V1 <voltage ≦ V2, current = I2
In the range of V2 <voltage ≦ V3, current = I3
In the range of V3 <voltage ≦ V4, current = I4
...
However, 0 <V1 <V2 <V3 <V4 ...
Further, I1>I2>I3> I4...

In this method, the rectangular IV curve of the solar cell string component is determined as follows. That is, the maximum output operating point voltage (Vpm0) in the standard state of the solar cell string component, the maximum output operating point current (Ipm0) in the standard state of the solar cell string component, the temperature rise Δ from 25 ° C. of the solar cell, the solar radiation Based on the intensity x, the temperature dependency β of the solar cell voltage, and the temperature dependency α of the solar cell current, the solar cell string component rectangular IV curve calculation function 3e calculates the maximum output operation in the usage state of the solar cell string component. The point output voltage Vpm and the maximum output operating point current Ipm in the usage state of the solar cell string component are approximated as follows.
Vpm = Vpm0 × (1 + Δ × β)
Ipm = Ipm0 × x × (1 + Δ × α)
Using this result, the solar cell string component rectangular IV curve calculation function 3e determines the rectangular IV curve of the solar cell string component as follows.
In the range of current ≦ Ipm, voltage = Vpm
In the range of Ipm <current, voltage = 0 (or voltage drop due to bypass diode)

  Based on the solar cell string component rectangle IV curve calculated by the solar cell string component rectangle IV curve calculation function 3e, the solar cell string IV curve calculation function 3c calculates a rectangle IV curve of the solar cell string. Furthermore, based on the solar cell string rectangular IV curve calculated by the solar cell string IV curve calculation function 3c, the solar cell array IV curve calculation function 3b calculates a rectangular IV curve of the solar cell array.

(Calculation method of predicted power generation)
Hereinafter, in the solar cell array AR1 of FIG. 3, the predicted power generation amount calculation device 1 calculates the predicted power generation amount of the solar cell cluster solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 that are the solar cell string components. A typical procedure will be described with reference to FIGS.

First, the predicted power generation amount calculation device 1 determines the maximum output operating point current Ipm and the maximum output operating point voltage Vpm of the solar cell module MD11, the solar cell module MD12, the solar cell module MD21, and the solar cell module MD22 from an external terminal. Receive. Here, it is assumed that the solar cell module MD11, the solar cell module MD12, the solar cell module MD21, and the solar cell module MD22 are received as Ipm0 being “5.0A” and Vpm0 being “42V”. The values of Ipm0 and Vpm0 are those in the standard state when the solar radiation intensity is 1 kW / m ² and the solar cell temperature is 25 ° C. Moreover, the predicted power generation amount calculation device 1 receives the temperature dependence β of the solar cell voltage. Here, it is assumed that β is received as “−0.3% / ° C.”. This means that when the temperature of the solar cell increases by 1 ° C., the solar cell voltage decreases by 0.3%. Further, the predicted power generation amount calculation device 1 receives the solar cell temperature function T. Here, it is assumed that T is received as “(temperature + 40 × insolation intensity (kW / m ² )) ° C.”. In general, the solar cell temperature depends on the installation state, the wind speed, the air temperature and the like in addition to the solar radiation intensity, but is expressed here as a function of the solar radiation intensity and the air temperature.

Next, the solar radiation intensity receiving unit 2 receives the solar radiation intensity of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24. Here, the solar cell cluster CL11 and the solar cell cluster CL12 are shaded, and the solar cell cluster CL11 and the solar cell cluster CL12 are “0.1 kW / m ² ”, the solar cell cluster CL13, the solar cell cluster CL14, and the sun. Assume that the battery cluster CL21 to the solar battery cluster CL24 receive “0.8 kW / m ² ” as the solar radiation intensity. These solar radiation intensity | strengths are the actual values by a solar radiation meter, for example. As the solar radiation intensity received by the solar radiation intensity receiving unit 2, the solar radiation intensity when there is no shadow is calculated, and the presence or absence of the influence of the shadow is determined in consideration of the obstacle. You may use what was calculated by subtracting by 70%.

Next, the array voltage calculation unit 3 calculates the rectangular IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 based on the solar radiation intensity received by the solar radiation intensity receiving unit 2. First, the procedure in which the array voltage calculation unit 3 calculates the current that can be output from the solar cell cluster CL11 will be described. The array voltage calculation unit 3 calculates the current that can be output from the solar cell cluster CL11 by multiplying the Ipm of the solar cell cluster CL11 by the solar radiation intensity of the solar cell cluster CL11. Here, the Ipm of the solar cell cluster CL11 is 5.0A equal to the Ipm of the solar cell module MD11, and the solar radiation intensity of the solar cell cluster CL11 is 0.1 kW / m ^2. The current that can be output from the battery cluster CL11 is calculated as 0.1 × 5.0A = 0.5A. In the same calculation method, the array voltage calculation unit 3 sets the current of the solar battery cluster CL12 to 0.5 A, the current that can be output from the solar battery cluster CL13, the solar battery cluster CL14, and the solar battery cluster CL21 to the solar battery cluster CL24. Is calculated as 4A.

Next, a procedure in which the array voltage calculation unit 3 calculates a voltage that can be output from the solar cell cluster CL11 will be described. First, the array voltage calculation unit 3 calculates the temperature of each solar cell cluster. Here, it is assumed that the solar cell cluster temperature is given as the outside air temperature + 40 × x ° C. when the solar radiation intensity is xkW / m ² , the outside air temperature is 25 ° C., and the solar cell cluster CL 11 has a solar radiation intensity of 0.1. A case of 1 kW / m ² will be described. In this case, the array voltage calculation unit 3 calculates the temperature of the solar cell cluster CL11 as 25 ° C. + 40 × 0.1 ° C. = 29 ° C. Next, the array voltage calculation unit 3 is β (here, −0.3% / ° C.) which is a voltage increase rate when the temperature of the solar cell cluster CL11 is increased by 1 ° C. from 25 ° C. which is the standard state. The voltage ratio is calculated as 1− (29−25) × 0.3 ÷ 100 = 0.908. Next, the array voltage calculation unit 3 calculates a voltage that can be output from the solar cell cluster CL11 by multiplying Vpm0 of the solar cell cluster CL11 and the voltage ratio. Here, since the solar cell module MD11 is configured by serial connection of the solar cell cluster CL11 and the solar cell cluster CL12, Vpm0 of the solar cell cluster CL11 is 21V which is half of 42V that is Vpm0 of the solar cell module MD11. is there. Therefore, the array voltage calculation unit 3 calculates the voltage that can be output from the solar cell cluster CL11 as 21 × 0.988 = 20.7748V. In the same calculation method, the array voltage calculation unit 3 sets the voltage of the solar cell cluster CL12 to 20.748V, the voltage that can be output from the solar cell cluster CL13, the solar cell cluster CL14, and the solar cell cluster CL21 to the solar cell cluster CL24. Is calculated as 18.984V.

  Thereafter, according to the method described in the patent document (Japanese Patent Laid-Open No. 2007-3390), the array voltage that is the voltage of the solar cell array AR1 when the array voltage calculation unit 3 obtains the maximum power generation amount of the solar cell array AR1. The procedure for calculating is described. The array voltage calculation unit 3 represents each solar cell cluster by a rectangle in which the height represents current and the width represents voltage based on the calculated rectangular IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24. To do. At that time, the solar cell cluster when the current is Ipm0 and the voltage is Vpm0 is expressed by a standard rectangle, and the height of the square is expanded and contracted according to the ratio of the outputable current and Ipm0, and the outputable voltage and Vpm0 The width of the quadrangle is expanded or contracted according to the ratio.

  FIG. 4 shows a quadrangle based on the rectangular IV curves of the solar cell clusters CL11-14 and the solar cell clusters CL21-24. For example, for solar cell cluster CL11, the current that can be output is 0.5A, and Ipm is 5.0A, so the height is 10% compared to the standard rectangle. Further, for the solar cell cluster CL11, the outputtable voltage is 20.748V and Vpm is 25V, so the width is about 83% compared to the standard rectangular shape. In addition, as shown in FIG. 4, the array voltage calculation unit 3 arranges quadrangles that represent solar cell clusters in a horizontal row for each solar cell string.

  Next, the array voltage calculation unit 3 rearranges from the left in the descending order of the current that can be output from the solar cell string in each solar cell string, that is, the height of the quadrangle representing the solar cell string, from the state of FIG. . Moreover, the array voltage calculation part 3 arranges the square of each solar cell string in piles. At this stage, the state shown in FIG. 5 is obtained. In FIG. 5, in the solar cell string ST1, the solar cell cluster CL13 and the solar cell cluster CL14 whose output voltages are larger than those of the solar cell cluster CL11 and the solar cell cluster CL12 are on the left side of the solar cell cluster CL11 and the solar cell cluster CL12. Sorted by Further, in FIG. 5, a quadrangle representing a solar cell cluster included in the solar cell string ST1 and a quadrangle representing a solar cell cluster included in the solar cell string ST2 are arranged one above the other.

  Next, the array voltage calculation unit 3 is a voltage that is a horizontal distance from the position to the left end of the boundary line and a vertical distance to the lower end of the boundary line at a position on the boundary line formed by a plurality of quadrangles. A position where the product with the current is maximum is calculated, and a voltage based on the position is calculated as an array voltage. FIG. 6 shows the maximum current, voltage, and power at the positions of the respective boundaries (1) to (7). In FIG. 6, since the maximum power is obtained in (6), the array voltage calculation unit 3 specifies 75.936 V that is the voltage in (6) as the array voltage.

  Next, the string current calculation unit 4 specifies the string currents of the solar cell string ST1 and the solar cell string ST2 based on the voltage position (6) at which the maximum power is obtained in FIG. In the voltage position of (6), the height of the solar cell string ST1 is the height (0.5A) of the solar cell cluster CL12, and the height of the solar cell string ST2 is the height (4A) of the solar cell cluster CL24. Therefore, the string current calculation unit 4 specifies the string current of the solar cell string ST1 as 0.5A and the string current of the solar cell string ST2 as 4A.

  Next, the predicted voltage calculation unit 5 calculates the predicted maximum voltages of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24. First, the predicted voltage calculation unit 5 obtains the maximum voltage that can be generated at 0.5 A that is the string current of the solar cell string ST1 for the solar cell clusters CL11 to 14. From FIG. 6, the predicted voltage calculation unit 5 has 20.748V as the maximum voltage that can be generated by the solar cell cluster CL11 and the solar cell cluster CL12, and 18.984V as the maximum voltage that can be generated by the solar cell cluster CL13 and the solar cell cluster CL14. Is calculated. Similarly, the predicted voltage calculation unit 5 obtains the maximum voltage that can be generated at 4A that is the string current of the solar cell string ST2 for the solar cell clusters CL21 to 24. Specifically, from FIG. 6, the predicted voltage calculation unit 5 calculates 18.984 V as the maximum voltage that can be generated by the solar cell clusters CL21 to CL24.

  Next, the predicted voltage calculation unit 5 calculates 79.464 V, which is the sum of the maximum voltages that can be generated by the calculated solar cell clusters CL11 to CL14, as the string maximum voltage of the solar cell string ST1. Similarly, the predicted voltage calculation unit 5 calculates 75.936 V, which is the sum of the maximum voltages that can be generated by the calculated solar cell clusters CL21 to CL24, as the maximum voltage of the strings of the solar cell strings ST2. Next, the predicted voltage calculation unit 5 maintains a voltage that is a ratio of the array voltage 75.936V to the maximum string voltage 79.464V of the solar cell string ST1 with respect to the calculated maximum voltage of each solar cell cluster CL11-14. By multiplying by the rate, the predicted voltage of each solar cell cluster CL11-14 is calculated. Similarly, the predicted voltage calculation unit 5 maintains a voltage that is a ratio of the array voltage 75.936V to the maximum string voltage 75.936V of the solar cell string ST2 with respect to the calculated maximum voltage of each solar cell cluster CL21-24. By multiplying by the rate, the predicted voltage of each solar cell cluster CL21-24 is calculated. For example, the predicted voltage calculation unit 5 multiplies 20.748, which can be generated by the solar cell cluster CL11, by 75.936 / 79.464, which is a voltage maintenance ratio, to calculate the predicted voltage of the solar cell cluster CL11. Is calculated to be about 19.827V.

  The operation of the predicted voltage calculation unit 5 will be generally described below. The array voltage calculation unit 3 sets the voltage of the solar cell array calculated by the solar cell array voltage calculation function 3a as Vary. The string current calculation unit 4 calculates the current of the solar cell string from the IV curve of the solar cell string calculated by the solar cell string IV curve calculation function 3c and Varry. This is called Istring. The predicted voltage calculation unit 5 first calculates the maximum voltage that each solar cell string component can output from the rectangular IV curve of each solar cell string component calculated by the solar cell string component rectangular IV curve calculation function 3e and the above Istring. Is determined as Vmax (i). Here, the suffix i is 1 ≦ i ≦ n, where n is the number of solar cell string components included in the solar cell string.

Next, in the string, the maximum voltage Vmax (i) that can be output by each solar cell string component is summed, and the voltage that can be output by the solar cell string is calculated as Vmax.
Vmax = Vmax (1) + Vmax (2) + Vmax (3) +... Vmax (n)
Next, the voltage maintenance ratio of the string is calculated as Varry / Vmax. Finally, the output voltage V (i) of each solar cell string component is predicted as follows.
V (i) = Vmax (i) × voltage maintenance ratio

  Next, the predicted power generation amount calculation unit 6 includes the string current 0.5A of the solar cell string ST1 calculated by the string current calculation unit 4 and the predicted voltage of the solar cell clusters CL11 to 14 calculated by the predicted voltage calculation unit 5. To calculate the predicted power generation amount of the solar cell clusters CL11-14. Similarly, the predicted power generation amount calculation unit 6 multiplies the string current 4A of the solar cell string ST2 calculated by the string current calculation unit 4 and the predicted voltage of the solar cell clusters CL21 to 24 calculated by the predicted voltage calculation unit 5. Thus, the predicted power generation amount of the solar cell clusters CL21 to 24 is calculated. For example, the predicted power generation amount calculation unit 6 calculates 0.5 × 19.827 = about 9.913 W as the predicted power generation amount of the solar cell cluster CL11. Similarly, the predicted power generation amount calculation unit 6 is about 9.913 W as the power generation amount of the solar cell cluster CL12, about 9.070 W as the power generation amount of the solar cell cluster CL13 and the solar cell cluster CL14, and the solar cell cluster CL21 to the solar cell cluster. About 75.936 W is calculated as the power generation amount of CL24.

(Another form of calculation method for predicted power generation)
Based on the solar radiation intensity received by the solar radiation intensity receiving unit 2, the array voltage calculation unit 3 outputs currents and voltages that can be output from the solar battery clusters CL11 to 14 and the solar battery clusters CL21 to 24 (of the solar cell string components). (IV curve) may be calculated. Further, the array voltage calculation unit 3 outputs currents and voltages that can be output from the solar cell string ST1 and the solar cell string ST2 based on the calculated IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 ( The IV curve of the solar cell string may be calculated. Further, the array voltage calculation unit 3 calculates the current and voltage that can be output from the solar cell array AR1 (IV curve of the solar cell array) based on the calculated IV curves of the solar cell string ST1 and the solar cell string ST2. May be. Furthermore, the array voltage calculation unit 3 may calculate the array voltage based on the calculated IV curve of the solar cell array AR1.

  The string current calculation unit 4 calculates the string current based on the IV curves of the solar cell string ST1 and the solar cell string ST2 calculated by the array voltage calculation unit 3 and the array voltage calculated by the array voltage calculation unit 3. May be. The predicted voltage calculation unit 5 is based on the IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 calculated by the array voltage calculation unit 3 and the string current calculated by the string current calculation unit 4. The predicted voltage may be calculated.

  Thereafter, in the solar cell array AR1 of FIG. 3, the predicted power generation amount calculation device 1 calculates the predicted power generation amount of the solar cell cluster solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 that are the solar cell string components. The specific procedure will be described with reference to FIGS.

First, the array voltage calculation unit 3 calculates the IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 at the solar radiation intensity of 1 kW / m ² . In general, an IV curve in a solar cell is obtained by solving a characteristic equation based on an equivalent circuit of the solar cell (see, for example, the following URL: http://www.eko.co.jp/eko/a /sys040101.html).

When the current of the solar cell is i and the voltage is v, the characteristic equation is expressed as follows, where iph, i0, a, Rs, and Rsh are constants.
i = iph-i0 {Exp (a * (v + i * Rs))-1}-(v + i * Rs) / Rsh
In order to obtain these parameters in the standard state of solar electrons, the following four equations can be used.
At current 0, voltage Voc0.
Voltage 0 at current Isc0.
Voltage Vpm0 at current Ipm0.
The power is maximum (stop value) at the current Ipm0 and the voltage Vpm0.
However, as described above, since there are five parameters, it is not possible to determine all of them. Therefore, the problem can be solved by setting Rsh = ∞ or Rs = 0 and determining the remaining four parameters.

The array voltage calculation unit 3 is “5.4 A” as the short-circuit current Isc of the solar cell module MD11, solar cell module MD12, solar cell module MD21, and solar cell module MD22, and “5.0A” as the maximum output operating point current Ipm. , Receiving “50V” as the open circuit voltage Voc and “42V” as the maximum output operating point voltage Vpm, and solving the characteristic equation using these values, the solar cell clusters CL11-14 at the solar radiation intensity of 1 kW / m ² , And the IV curve of solar cell cluster CL21-24 is calculated. 7 and 8 are diagrams showing IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24. FIG. A curve a in FIG. 7 shows the IV curves of the solar cell cluster CL11 and the solar cell cluster CL12 calculated by the array voltage calculation unit 3 at the solar radiation intensity 1 kW / m ^2, and a curve b in FIG. 8 shows the solar radiation intensity 1 kW / m 2. ⁴ shows the IV curves of the solar cell cluster CL13, the solar cell cluster CL14, and the solar cell clusters CL21 to 24 calculated by the array voltage calculation unit 3 in FIG.

Next, the array voltage calculation unit 3 calculates the IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 based on the actual solar radiation intensity received by the solar radiation intensity receiving unit 2. Here, the solar cell cluster CL11 and the solar cell cluster CL12 are shaded, and the solar radiation intensity receiving unit 2 is configured such that the solar battery cluster CL11 and the solar cell cluster CL12 have solar radiation intensity of 0.1 kW / m ² , the solar cell cluster CL13, It is assumed that the solar cell clusters CL14 and the solar cell clusters CL21 to CL24 receive the solar radiation intensity as 0.8 kW / m ² .

That is, the array voltage calculation unit 3 calculates the IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 at the solar radiation intensity by multiplying the parameter relating to the short circuit current in the characteristic equation by the solar radiation intensity ratio. To do. A curve a ′ in FIG. 7 shows the IV curves of the solar cell cluster CL11 and the solar cell cluster CL12 calculated by the array voltage calculation unit 3 at the solar radiation intensity of 0.1 kW / m ^2, and a curve b ′ in FIG. intensity 0.8 kW / ^{m 2} photovoltaic cluster CL13 is calculated by the array voltage calculation unit 3 in a diagram showing the IV curve of the solar cell clusters CL14, and photovoltaic cluster CL21～24.

  Furthermore, the array voltage calculation unit 3 converts the IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 indicated by the curve a ′ in FIG. 7 and the curve b ′ in FIG. 8 into the solar cell string ST1 and the solar cell. By combining in the string ST2, the IV curves of the solar cell string ST1 and the solar cell string ST2 are calculated. When combining, for example, when the current becomes a negative value, the value of the current is set to “0”.

  Next, the array voltage calculation unit 3 calculates the IV curve of the solar cell array AR1 by synthesizing the IV curves of the solar cell string ST1 and the solar cell string ST2. In the synthesis, for example, when the voltage becomes a negative value, the voltage value is set to “0”. FIG. 9 is a diagram illustrating an IV curve of the solar cell array AR1 calculated by the array voltage calculation unit 3. Curve c in FIG. 9 shows the relationship between voltage and current (continuous IV curve) in solar cell array AR1, and curve d in FIG. 9 shows the relationship between voltage and power in solar cell array AR1 (continuous) derived from curve c. PV curve). Next, the array voltage calculation part 3 calculates | requires the array voltage which is a voltage when the maximum electric power generation amount of solar cell array AR1 is obtained from the curve d of FIG. Here, the array voltage calculation unit 3 calculates 75.008 V as the array voltage.

  Thereafter, the string current calculation unit 4 uses the array voltage 75.. Calculated by the array voltage calculation unit 3 in the string IV curve of the solar cell string ST1 and the string IV curve of the solar cell string ST2 calculated by the array voltage calculation unit 3. The current at 008 V is calculated as the solar cell string ST1 and the solar cell string ST2 string current, respectively. Here, the string current calculation unit 4 calculates 0.490A as the string current of the solar cell string ST1, and calculates 3.976A as the string current of the solar cell string ST2.

  Next, the predicted voltage calculation unit 5 is the solar cell calculated by the string current calculation unit 4 in the cluster continuous IV curves of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 calculated by the array voltage calculation unit 3. The voltages at the string currents of the battery string ST1 and the solar cell string ST2 are calculated as the predicted voltages of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24, respectively. Here, the predicted voltage calculation unit 5 sets the predicted voltage of the solar cell cluster CL11 and the solar cell cluster CL12 to 15.363V, the predicted voltage of the solar cell cluster CL13 and the solar cell cluster CL14 to 22.141V, and the solar cell cluster CL21 to the solar cell. The predicted voltage of the battery cluster CL24 is calculated as 18.752V.

  The predicted power generation amount calculation unit 6 includes the string currents of the solar cell strings ST1 and the solar cell strings ST2 calculated by the string current calculation unit 4, the solar cell clusters CL11 to 14 calculated by the predicted voltage calculation unit 5, and By multiplying the predicted voltages of the solar cell clusters CL21 to 24, the predicted power generation amounts of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 are calculated. Here, the predicted power generation amount calculation unit 6 sets the predicted power generation amount of the solar cell cluster CL11 and the solar cell cluster CL12 to 7.525V, the predicted voltage of the solar cell cluster CL13 and the solar cell cluster CL14 to 10.845V, and the solar cell clusters CL21 to CL21. The predicted voltage of the solar battery cluster CL24 is calculated as 74.559V.

(Display cluster status)
The display unit 7 displays the state of the solar cell string constituent elements constituting the solar cell array on the output device 55 so as to correspond to the physical position of the solar cell string constituent elements in the actual solar cell array. The display unit 7 displays a numerical value or a figure based on the predicted power generation amount of the solar cell string component calculated by the predicted power generation amount calculation unit 6 on the output device 55 as the state of the solar cell string component. Further, the display unit 7 uses the numerical value or graphic based on the solar radiation intensity received by the solar radiation intensity receiving unit 2 as the state of the solar cell string constituent element and the numerical value or graphic based on the predicted power generation amount of the solar cell string constituent element. You may display on the output device 55. FIG.

  Fig.10 (a) is a figure which shows the actual solar radiation state in a solar cell array. Each of the five columns in FIG. 10A shows a solar cell string. Each solar cell string is composed of eight circles, and one circle corresponds to a solar cell cluster. That is, in the solar cell array of FIG. 10A, eight solar cell clusters are electrically connected in series to form one solar cell string, and the five solar cell strings configured as such are electrically connected. Are connected in parallel to form one solar cell array. In FIG. 10A, the circle corresponding to the solar cell cluster indicates the solar radiation state in the solar cell cluster, the white circle indicates the sun, and the black circle indicates the shade. That is, in FIG. 10A, only the upper right solar cell cluster is shaded, and the other solar cell clusters are sunny.

  FIG.10 (b) or FIG.10 (c) shows the electric power generation state which the solar cell cluster in the solar cell array under the condition of Fig.10 (a) can take. FIG. 10B shows a power generation state when the solar cell array maintains a current in the situation of FIG. 10A, and FIG. 10C shows the solar cell array in the situation of FIG. Indicates the power generation state when the voltage is maintained. The squares in FIGS. 10B and 10C correspond to the solar cell clusters indicated by the circles in FIG. 10A, and the physical positions thereof also correspond. Further, the connection relationship between the solar cell clusters in FIG. 10 (a) corresponds to the connection relationship between the solar cell clusters in FIG. 10 (b) and FIG. 10 (c). As for the physical configuration, FIG. 10 (a) corresponds to FIG. 10 (b) and FIG. 10 (c).

  In FIG. 10B and FIG. 10C, the square corresponding to the solar cell cluster indicates the power generation amount in the solar cell cluster, and the white square indicates 100% power generation amount that can be output by the solar cell cluster. Black squares indicate 0% power generation. In the solar cell string in the first row from the top in FIG. 10B, the solar cell cluster on the upper right is shaded, so that the power generation amount is indicated by a black square with 0%, and the other solar cell clusters have a power generation amount of 100%. It is indicated by a white square. FIG. 10 (b) shows the state when the solar cell array maintains the current, and the solar cell clusters in the solar cell strings other than the first row from the top are 7/8 times the white square to maintain the current. A hatched square indicates that the power generation amount is 87.5%, and the power generation amount is reduced to 87.5%.

  On the other hand, FIG. 10C shows the state when the solar cell array maintains the voltage. In this case, the solar cell strings in the first column from the top cannot generate power, and the solar cell clusters in the remaining solar cell strings It shows that the amount of power generation is 100%. In this case, the current of the solar cell array is about 4/5 times.

  When FIG. 10 (b) and FIG. 10 (c) are compared, it is the state of FIG. 10 (b) that has a large amount of power generation as a solar cell array. Therefore, the display unit 7 displays the diagram shown in FIG. 10B on the output device 55 when the solar cell array is in the state shown in FIG. In FIG. 10B, a graphic based on the predicted power generation amount of the solar cell cluster is displayed on the display unit 7, but a numerical value based on the predicted power generation amount may be displayed, and a numerical value or graphic based on the solar radiation intensity may be displayed. May be displayed at the corresponding location.

  FIG. 11A shows a state where two solar cell clusters from the right in the first solar cell string from the top in FIG. 10A are shaded. 11 (b) or 11 (c) shows a power generation state that can be taken by the solar cell cluster in the solar cell array under the situation shown in FIG. 11 (a). FIG. 11B shows a power generation state when the solar cell array maintains current in the situation of FIG. 11A, and FIG. 11C shows the solar cell array in the situation of FIG. Indicates the power generation state when the voltage is maintained.

  In the case of FIG. 11 (b), the power generation amount in the hatched square is 6/8 times that of the white square, and in the case of FIG. 11 (c), the current is about 4/5 times as in FIG. 10 (c). When FIG. 11B and FIG. 11C are compared, it is the state of FIG. 11C that has a large amount of power generation as a solar cell array. Therefore, the display unit 7 displays the diagram shown in FIG. 11C on the output device 55 when the solar cell array is in the state of FIG.

(Process flow)
Next, processing of the predicted power generation amount calculation device 1 will be described. FIG. 12 is a flowchart showing the process of the predicted power generation amount calculation apparatus 1.

  First, the solar radiation intensity receiving unit 2 receives solar radiation intensity of the solar cell clusters CL11 to 14 and the solar battery clusters CL21 to 24 (S1, solar radiation intensity receiving step). Next, the array voltage calculation unit 3 calculates the array voltage of the solar cell array AR1 based on the solar radiation intensity (S2, array voltage calculation step). Next, the string current calculation unit 4 calculates the string current of the solar cell strings ST1 and ST2 based on the solar radiation intensity and the array voltage (S3, string current calculation step). Next, the predicted voltage calculation unit 5 calculates the predicted voltages of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 based on the solar radiation intensity (S4, predicted voltage calculation step). Next, the predicted power generation amount calculation unit 6 calculates the predicted power generation amounts of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 based on the string current and the predicted voltage (S5, predicted power generation amount calculation step). ). Next, the display unit 7 displays the states of the solar cell clusters CL11 to 14 and the solar cell clusters CL21 to 24 on the output device 55 based on the predicted power generation amount (S6).

(Points to note in power generation calculation)
The calculation of the predicted power generation amount is preferably performed in consideration of the installation direction of each solar cell and the influence of a shadow falling on each solar cell. If these are not taken into account, the solar radiation intensity on the solar cell string component cannot be accurately calculated, and thus the predicted power generation amount may not be accurately evaluated. Specifically, the IV curve of the solar cell string constituent element is calculated in consideration of the installation direction and the shadow.

  The calculation of the power generation amount of the solar cell array and the predicted power generation amount of the solar cell string components is preferably performed in units of 2 hours at the longest from the instantaneous value. If the calculation is performed in units of time longer than this, since the solar radiation intensity of the solar cell string component and the relative value of the solar radiation intensity between the solar cell string components change during that time, the predicted power generation amount cannot be accurately calculated. There is a fear. When calculating and displaying the power generation amount of the solar cell array and the predicted power generation amount of each solar cell string component over 2 hours, divide the target time zone into multiple time zones of 2 hours or less. It is preferable to calculate and display the power generation amount of the solar cell array and the predicted power generation amount of each solar cell string component for each time zone, and to calculate and display the entire target time zone by integrating them.

(Another form of IV curve calculation method)
As a method of calculating the IV curve of the solar cell string constituent element, a method of calculating as a “continuous IV curve” and a method of calculating as a “rectangular IV curve” have been described. However, the present invention is not limited to these two methods.

In the method of calculating the rectangular IV curve when the short-circuit current of the solar cell string component in the operating state is Isc, the open circuit voltage is Voc, the maximum output operating point current is Ipm, and the maximum output operating point voltage is Vpm, the IV curve The IV curve is approximated by connecting the following three points with a straight line.
First point: voltage = 0, current = Ipm
Second point: voltage = Vpm, current = Ipm
Third point: voltage = Vpm, current = 0
A method of approximating the IV curve by connecting the following three points with straight lines instead of the above three points can be exemplified as a third method following the “continuous IV curve” and the “rectangular IV curve”.
First point: voltage = 0, current = Isc
Second point: voltage = Vpm, current = Ipm
Third point: voltage = Voc, current = 0

Further, in the method of calculating the “continuous IV curve” mentioned as a method of approximating the IV curve by a smooth function, when determining the IV curve of the solar cell string component based on the characteristic equation, the parameter is set to four. In order to reduce, an approximation of either setting the series resistance Rs as 0 or setting the shunt resistance Rsh as ∞ was performed. As another method, a method of determining the coefficient a of the exponential function by the following equation and approximating the IV curve with a smooth function including both Rsh and Rs can be exemplified.
a = q / (nd × k × Tb)
q: Elementary quantity of electricity nd: Diode factor (1 for silicon solar cells)
k: Boltzmann constant Tb: absolute temperature of solar cell

  DESCRIPTION OF SYMBOLS 1 ... Predicted electric power generation calculation device, 2 ... Solar radiation intensity receiving part, 3 ... Array voltage calculation part, 4 ... String current calculation part, 5 ... Predictive voltage calculation part, 6 ... Predictive electric power generation calculation part, 7 ... Display part.

Claims (7)

Regarding a solar cell array configured by electrically connecting solar cell strings configured by electrically connecting solar cell string components that receive sunlight to generate electricity in series, the solar cell string A predicted power generation amount calculation device that calculates a predicted power generation amount of a component,
Solar radiation intensity receiving means for receiving solar radiation intensity of the solar cell string component;
Based on the solar radiation intensity received by the solar radiation intensity receiving means, an array voltage calculating means for calculating an array voltage that is a voltage of the solar battery array when the maximum power generation amount of the solar battery array is obtained;
String current calculation means for calculating a string current that is a current of the solar cell string at the array voltage calculated by the array voltage calculation means;
Predicted voltage calculation means for calculating a predicted voltage that is a predicted voltage of the solar cell string component in the string current;
A predicted power generation amount calculating unit that calculates a predicted power generation amount of the solar cell string component based on the string current calculated by the string current calculation unit and the predicted voltage calculated by the predicted voltage calculation unit; ,
A predicted power generation amount calculation device comprising: The array voltage calculation means includes
Based on the solar radiation intensity received by the solar radiation intensity receiving means, calculates the current and voltage that can be output by the solar cell string component,
Based on the calculated current and voltage that can be output by the solar cell string component, calculate the current and voltage that can be output by the solar cell string,
Based on the calculated current and voltage that the solar cell string can output, calculate the current and voltage that can be output by the solar cell array,
Based on the calculated current and voltage that can be output by the solar cell array, the array voltage is identified,
The string current calculation means calculates the string current based on the current and voltage that can be output by the solar cell string calculated by the array voltage calculation means and the array voltage calculated by the array voltage calculation means. Identify,
The predicted voltage calculation means calculates the predicted voltage based on the maximum voltage that can be output by the solar cell string component calculated by the array voltage calculation means and the array voltage.
The predicted power generation amount calculation device according to claim 1. The predicted voltage calculation means includes
The maximum voltage that can be output by the solar cell string component calculated by the array voltage calculation means is the string element maximum voltage that is the voltage of the solar cell string component,
Based on the string element maximum voltage, a string maximum voltage that is a maximum voltage of the solar cell string at the string current is calculated;
The predicted voltage is calculated by multiplying the string element maximum voltage by a voltage maintenance ratio that is a ratio of the array voltage calculated by the array voltage calculation means to the calculated string maximum voltage.
The predicted power generation amount calculation apparatus according to claim 2. The array voltage calculation means includes
Based on the solar radiation intensity received by the solar radiation intensity receiving means, calculate a current and voltage that can be output by the solar cell string component,
Based on the calculated output current and voltage of the solar cell string component, the output current and voltage of the solar cell string are calculated,
Based on the calculated current and voltage that can be output from the solar cell string, the current and voltage that can be output from the solar cell array are calculated,
Based on the calculated output current and voltage of the solar cell array, the array voltage is calculated,
The string current calculation means calculates the string current based on the output current and voltage of the solar cell string calculated by the array voltage calculation means and the array voltage calculated by the array voltage calculation means. Calculate
The predicted voltage calculation means is configured to perform the prediction based on the current and voltage that can be output from the solar cell string component calculated by the array voltage calculation means and the string current calculated by the string current calculation means. Calculate the voltage,
The predicted power generation amount calculation device according to claim 1. Display means for displaying the state of the solar cell string component constituting the solar cell array so as to correspond to the physical position of the solar cell string component in the actual solar cell array,
The display means displays a numerical value or a figure based on the predicted power generation amount of the solar cell string component calculated by the predicted power generation amount calculation unit as a state of the solar cell string component,
The predicted power generation amount calculation device according to any one of claims 1 to 4, wherein: The display means uses a numerical value or a figure based on the solar radiation intensity received by the solar radiation intensity receiving means as a state of the solar cell string constituent element together with a numerical value or a figure based on the predicted power generation amount of the solar cell string constituent element. indicate,
The predicted power generation amount calculation device according to claim 5. Regarding a solar cell array configured by electrically connecting solar cell strings configured by electrically connecting solar cell string components that receive sunlight to generate electricity in series, the solar cell string A predicted power generation amount calculation device for calculating a predicted power generation amount of a component element receives a solar radiation intensity reception step of receiving the solar radiation intensity of the solar cell string component element;
The predicted power generation amount calculation device calculates an array voltage that is a voltage of the solar cell array when the maximum power generation amount of the solar cell array is obtained based on the solar radiation intensity received in the solar radiation intensity receiving step. An array voltage calculation step;
The predicted power generation amount calculation device calculates a string current that is a current of the solar cell string in the array voltage calculated in the array voltage calculation step;
A predicted voltage calculating step in which the predicted power generation amount calculating device calculates a predicted voltage that is a predicted voltage of the solar cell string component in the string current;
The predicted power generation amount calculation device calculates the predicted power generation amount of the solar cell string component based on the string current calculated in the string current calculation step and the predicted voltage calculated in the predicted voltage calculation step. A predicted power generation amount calculating step to calculate,
Calculation method of predicted power generation including

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