WO2013046554A1

WO2013046554A1 - Solar cell array and solar power system

Info

Publication number: WO2013046554A1
Application number: PCT/JP2012/005661
Authority: WO
Inventors: 大二兼松
Original assignee: 三洋電機株式会社
Priority date: 2011-09-29
Filing date: 2012-09-06
Publication date: 2013-04-04
Also published as: JP2014239083A

Abstract

Provided is a solar cell array (100d) in which a plurality of solar cell modules (11, 12, 13, 21, 22, 23) are connected in serial parallel in a matrix shape. At least one of both ends of the plurality of solar cell modules (11, 12, 13, 21, 22, 23) is connected to voltage sources (E1, E2, E3). For instance, it would be permissible the voltage sources (E1, E2, E3) to be connected in parallel to respective parallel stages of a serial parallel circuit wherein the plurality of solar cell modules (11, 12, 13, 21, 22, 23) are connected in serial parallel.

Description

Solar cell array and photovoltaic system

The present invention relates to a solar cell array including a plurality of solar cell modules and a solar power generation system.

】 In response to global warming and nuclear accidents, attention has been focused on natural energy. In particular, solar power generation has become popular not only for business use but also for home use. Since the power generated by one solar cell is small, a plurality of solar cells are combined to form a solar cell module (also referred to as a solar cell panel), and a plurality of solar cell modules are combined to form a solar cell array. It is formed. The plurality of solar cell modules forming the solar cell array are connected in series to ensure a desired voltage, and are further connected in parallel to ensure a desired current (for example, see Patent Document 1).

JP 2006-173539 A

When some solar cell modules of the plurality of solar cell modules constituting the solar cell array are shaded, some of the solar cell modules do not generate power, so the output power of the solar cell array is greatly reduced. The main cause of this power decrease is a decrease in output current, and even if a bypass diode is provided, the power decrease cannot be avoided.

This invention is made | formed in view of such a condition, The objective is a power fall when a part of solar cell module stops an electric power generation in a solar cell array provided with the series parallel circuit to which the several solar cell module was connected. It is in providing the technique which suppresses.

A solar cell array according to an aspect of the present invention is a solar cell array in which a plurality of solar cell modules are connected in series and parallel, and a voltage source is connected to at least one end of the plurality of solar cell modules. .

Another aspect of the present invention is a solar power generation system. This solar power generation system includes a solar cell array in which a plurality of solar cell modules are connected in series and parallel, and a voltage source connected to at least one end of the plurality of solar cell modules.

According to the present invention, in a solar cell array including a series-parallel circuit to which a plurality of solar cell modules are connected, it is possible to suppress power reduction when some of the solar cell modules stop generating power.

5 is a diagram showing a solar cell array according to Comparative Example 1. FIG. 10 is a diagram showing a solar cell array according to Comparative Example 2. FIG. It is a figure which shows the solar cell array for demonstrating the basic principle of this invention. It is a figure which shows the IV characteristic for demonstrating the basic principle of this invention. It is a figure which shows an example of the solar cell array which concerns on embodiment of this invention. It is a figure which shows the structural example of the solar cell array shown in FIG. It is a figure which shows another example of the solar cell array which concerns on embodiment of this invention. It is a figure which shows the structural example of a small-scale photovoltaic power generation system. It is a figure which shows the structural example of the solar energy power generation system which concerns on the embodiment which added the voltage source for electric current compensation to the solar energy power generation system shown in FIG. FIG. 10 is a diagram illustrating an internal configuration example of the AC-DC converter unit illustrated in FIG. 9. It is a figure which shows the structural example of a large-scale photovoltaic power generation system. It is a figure which shows the structural example of the photovoltaic power generation system which concerns on the embodiment which added the voltage source for electric current compensation to the photovoltaic power generation system shown in FIG. It is a figure which shows the structural example of the solar energy power generation system which concerns on the embodiment which added the voltage source for electric current compensation to the solar energy power generation system (one of the solar cell modules has failed) shown in FIG. It is a figure which shows the structural example of the solar energy power generation system which concerns on the photovoltaic power generation system (shadow on a part of solar cell module) shown in FIG. It is a figure which shows the state which the some solar cell module failed in the solar power generation system shown in FIG. It is a figure which shows the structural example (series type) of the photovoltaic power generation system which concerns on the photovoltaic power generation system shown in FIG. It is a figure which shows the structural example (parallel type) of the photovoltaic power generation system which concerns on the photovoltaic power generation system shown in FIG.

First, the basic principle of the present invention will be described. FIG. 1 is a diagram showing a solar cell array 100a according to Comparative Example 1. The solar cell array 100a according to Comparative Example 1 includes a plurality of series circuits in which a plurality of solar cell modules are connected in series, and the plurality of series circuits are connected in parallel. In the example of FIG. 1, a first series circuit in which a 1.1 solar cell module 11, a 1.2 solar cell module 12, and a 1.3 solar cell module 13 are connected in series, and a 2.1 solar cell module. 21, 2.2 solar cell module 22 and 2.3 solar cell module 23 are connected in parallel to the second series circuit connected in series.

The solar cell module includes a current source I that generates a photocurrent proportional to incident light, a diode D, a parallel resistance Rsh (shunt resistance) caused by a leakage current of a pn junction, and a series resistance Rs of a connection that collects current at a terminal. Approximated.

In the circuit shown in FIG. 1, when the 1.2 solar cell module 12 is shaded, the 1.2 solar cell module 12 does not generate power. In this case, not only the current of the 1.2 solar cell module 12 becomes invalid, but also the current of the entire first series circuit including the 1.2 solar cell module 12 becomes invalid. Therefore, the output power of the entire solar cell array 100a is about ½. In addition, a malfunction may occur in the 1.2 solar cell module 12 due to the electric power generated by the 1.1 solar cell module 11 and the 1.3 solar cell module 13.

FIG. 2 is a diagram showing a solar cell array 100b according to Comparative Example 2. The solar cell array 100b according to Comparative Example 2 has a configuration in which the nodes of the corresponding stages of the first series circuit and the second series circuit are connected as compared with the solar cell array 100a according to Comparative Example 1. That is, a node between the 1.1 solar cell module 11 and the 1.2 solar cell module 12 and a node between the 2.1 solar cell module 21 and the 2.2 solar cell module 22 A node between the 1.2 solar cell module 12 and the 1.3 solar cell module 13, a node between the 2.2 solar cell module 22 and the 2.3 solar cell module 23, and Is connected.

Thereby, even when the 1.2th solar cell module 12 is shaded, the 1.2th solar cell module 12 is kept in forward bias by the electromotive voltage of the 2.2th solar cell module 22. Therefore, it can suppress that a malfunction generate | occur | produces in the 1.2st solar cell module 12. FIG. However, the point that the output power of the entire solar cell array 100b is about ½ is the same as in Comparative Example 1.

FIG. 3 is a diagram showing a solar cell array 100c for explaining the basic principle of the present invention. The solar cell array 100c has a configuration in which a second voltage source E2 is added as compared with the solar cell array 100b according to Comparative Example 2. The second voltage source E <b> 2 is connected to both ends of the 1.2 solar cell module 12 and the 2.2 solar cell module 22. That is, the second voltage source E2 is shaded and functions as an alternative battery for the 1.2th solar cell module 12 that is not generating power.

FIG. 4 is a diagram showing IV characteristics for explaining the basic principle of the present invention. The horizontal axis represents voltage and the vertical axis represents current. 4 shows the IV characteristics of the solar cell array 100a (without partial shadow) shown in FIG. 1, the IV characteristics of the solar cell array 100a (with partial shadow) shown in FIG. 1, and the solar cell array 100b shown in FIG. Experimental data of IV characteristics (with partial shadows) and IV characteristics of the solar cell array 100c (with partial shadows) shown in FIG. 3 are shown. For the sake of convenience, each solar cell module was replaced with a solar cell having a small output. The output voltage at the maximum power point of each solar battery cell is about 1 V, and the output current at that time is about 70 mA. The electromotive voltage of the second voltage source E2 is about 1V. The above-mentioned “with partial shadow” refers to a state in which a solar cell corresponding to the first solar cell module 12 is shaded and the solar cell does not generate power. Hereinafter, for ease of explanation, the solar battery cell is referred to as a solar battery module in accordance with the description example in FIGS. 1 to 3.

As a result of the experiment, the maximum power point of the solar cell array 100a (without partial shadow) shown in FIG. 1 is 415.4 mW, and the maximum power point of the solar cell array 100a (with partial shadow) shown in FIG. 1 is 206.9 mW, shown in FIG. The maximum power point of the solar cell array 100b (with partial shadow) was measured as 248.8 mW, and the maximum power point of the solar cell array 100c (with partial shadow) shown in FIG. 3 was measured as 418.7 mW. Moreover, the maximum current point of the solar cell array 100c (with partial shadow) shown in FIG. 3 was measured to be 141.4 mA.

When comparing the maximum power points of the solar cell array 100a (with partial shadow) shown in FIG. 1 and the solar cell array 100c (with partial shadow) shown in FIG. 3, the former is 206.9 mW and the latter is 418.7 mW. That is, by adopting the circuit configuration shown in FIG. 3, an increment of 418.7-206.9 = 211.8 mW can be obtained. If the power input to the solar cell array 100c by the second voltage source E2 is 70.7 mW, the net increment is 211.8-70.7 = 141.1 mW. The electric power that the second voltage source E2 inputs to the solar cell array 100c is assumed to be a half current (141.4 / 2) at the maximum power point of the solar cell array 100c and an electromotive voltage (1V) of the second voltage source E2. did.

A series circuit to which a non-power generating solar cell module belongs is basically invalid, but by connecting a voltage source having an electromotive voltage equivalent to that of the solar cell module in parallel with the solar cell module, the solar cell module Can be restored in a pseudo manner. That is, the electromotive force of the voltage source restores the electromotive force of the series circuit, which is a large plus.

FIG. 5 is a diagram showing an example of the solar cell array 100d according to the embodiment of the present invention. The solar cell array 100d according to the embodiment includes a series-parallel circuit in which a plurality of solar cell modules are connected in series and parallel in a matrix. A solar cell array 100d shown in FIG. 5 is a series-parallel circuit having a series number of 3 and a parallel number of 2, similar to the

solar cell arrays

100b and 100c shown in FIGS. The number of series and the number of parallel are not limited to these numbers. However, the number of series is assumed to be plural. As will be described later, the parallel number may be one.

In the solar cell array 100d according to the embodiment, a voltage source other than the solar cell module is connected in parallel to each parallel stage of the series-parallel circuit. The voltage sources connected to the respective parallel stages are connected in series, and the plurality of voltage sources connected in series are connected between the positive electrode side output terminal and the negative electrode side output terminal of the solar cell array 100d.

In the example shown in FIG. 5, the first voltage source E1 is connected in parallel with the 1.1st solar cell module 11 and the 2.1st solar cell module 21, and the second voltage source E2 is the 1.2th solar cell module 12. The third voltage source E3 is connected in parallel with the 1.3 solar cell module 13 and the 2.3 solar cell module 23. The first voltage source E1, the second voltage source E2, and the third voltage source E3 are connected in series, and the series circuit is connected between the positive electrode side output terminal and the negative electrode side output terminal of the solar cell array 100d.

In the circuit configuration shown in FIG. 5, the sum of the currents flowing through the parallel stages is all equal according to Kirchhoff's current law. Accordingly, the 1.1 solar cell module 11, the 1.2 solar cell module 12, the 1.3 solar cell module 13, the 2.1 solar cell module 21, the 2.2 solar cell module 22, and the second. When a shadow occurs in any one of the three solar cell modules 23, the current is compensated by the first voltage source E1, the second voltage source E2, or the third voltage source E3 as an alternative power source for the non-power generating solar cell module. Is done. Therefore, the amount of decrease in the output power of the solar cell array 100d is less than the state in which the first voltage source E1, the second voltage source E2, and the third voltage source E3 are not connected even if the electromotive force of the voltage source that compensates the current is subtracted. Reduced.

The same applies when a shadow is generated in two solar cell modules (for example, the 1.1 solar cell module 11 and the 1.2 solar cell module 12) belonging to the same series circuit. However, when a partial shadow occurs in all the solar cell modules belonging to the same series circuit, the amount of decrease in the output power of the solar cell array 100d becomes substantially equal to the electromotive force of the voltage source that compensates for the current. E1, the second voltage source E2, and the third voltage source E3 are substantially equal to the state where they are not connected.

When a shadow is generated in two solar cell modules belonging to the same parallel stage (for example, the 1.1 solar cell module 11 and the 2.1 solar cell module 21), as an alternative power source for the non-power generating solar cell module The current for one solar cell module is supplemented by the first voltage source E1, the second voltage source E2, or the third voltage source E3. In the state where the first voltage source E1, the second voltage source E2 and the third voltage source E3 are not connected, the series-parallel circuit is invalid, but in the state where they are connected, one series circuit is valid. . In order to enable two series circuits, two voltage sources connected to each parallel stage may be provided in parallel.

FIG. 6 is a diagram showing a configuration example of the solar cell array 100d shown in FIG. In the solar cell array 100e shown in FIG. 6, a step-down circuit (more specifically, a step-down DC-DC converter) is used as a voltage source. That is, the first DC-DC converter 31, the second DC-DC converter 32, and the third DC-DC converter 33 are used as the first voltage source E1, the second voltage source E2, and the third voltage source E3.

The positive output terminal + Vout of the first DC-DC converter 31 is connected to the positive output terminal of the solar cell array 100e, and the negative output terminal -Vout of the first DC-DC converter 31 is the positive output of the second DC-DC converter 32. Connected to terminal + Vout. The negative output terminal -Vout of the second DC-DC converter 32 is connected to the positive output terminal + Vout of the third DC-DC converter 33, and the negative output terminal -Vout of the third DC-DC converter 33 is the negative electrode of the solar cell array 100e. Connected to the side output terminal. The positive input terminal + Vin of the first DC-DC converter 31, the second DC-DC converter 32, and the third DC-DC converter 33 is connected to the positive output terminal of the solar cell array 100e, and the negative input terminal -Vin is connected to the sun. Connected to the negative output terminal of the battery array 100e. The output voltage of the solar cell array 100e is used as the power supply voltage for the first DC-DC converter 31, the second DC-DC converter 32, and the third DC-DC converter 33.

A general switching power supply can be used for the first DC-DC converter 31, the second DC-DC converter 32, and the third DC-DC converter 33. The type of switching power supply is not particularly limited.

FIG. 7 is a diagram showing another example of the solar cell array 100f according to the embodiment of the present invention. A solar cell array 100f shown in FIG. 7 includes a series circuit in which a plurality of solar cell modules are connected in series. More specifically, it includes a series circuit in which a 1.1st solar cell module 11, a 1.2th solar cell module 12, and a 1.3th solar cell module 13 are connected in series.

In the solar cell array 100f shown in FIG. 7, a voltage source is connected to both ends of each of the plurality of solar cell modules. The voltage sources connected to the respective solar cell modules are connected in series, and the plurality of voltage sources connected in series are connected between the positive electrode side output terminal and the negative electrode side output terminal of the solar cell array 100f.

In the example shown in FIG. 7, the first voltage source E1 is connected in parallel with the 1.1 solar cell module 11, the second voltage source E2 is connected in parallel with the 1.2 solar cell module 12, and the third voltage A source E3 is connected in parallel with the 1.3st solar cell module 13. The first voltage source E1, the second voltage source E2, and the third voltage source E3 are connected in series, and the series circuit is connected between the positive electrode side output terminal and the negative electrode side output terminal of the solar cell array 100f. That is, as compared with the solar cell array 100d shown in FIG. 5, the 2.1 solar cell module 21, the 2.2 solar cell module 22, and the 2.3 solar cell module 23 are omitted. The first voltage source E1, the second voltage source E2, and the third voltage source E3 are configured by the first DC-DC converter 31, the second DC-DC converter 32, and the third DC-DC converter 33 as shown in FIG. Also good.

As described above, according to the present embodiment, in a solar cell array including a series-parallel circuit to which a plurality of solar cell modules are connected, by connecting a voltage source for current compensation in parallel with the solar cell module, It is possible to suppress power reduction when some of the solar cell modules stop generating power. Moreover, a self-contained system can be constructed by acquiring the power supply voltage of the voltage source from the output of the solar cell array. In this case, wiring from the power system is not necessary.

In the above-described embodiment, the circuit configuration for acquiring the operating power source of the voltage source from the output of the solar cell array is shown, but the present invention is not limited to this. The AC voltage supplied from the power system may be rectified and used. Further, in a system in which a solar power generation system and a power storage system cooperate, a voltage charged in a storage battery from a solar battery or a power system may be used.

In the

solar cell arrays

100d, 100e, and 100f shown in FIGS. 5, 6, and 7, one voltage source is connected to all the stages of the series-parallel circuit or series circuit, but it is not always necessary to connect the voltage source to all the stages. Absent. For example, it is conceivable that a voltage source is not connected to a stage having a low probability of being a shadow.

Moreover, a plurality of voltage sources may be connected in parallel to one stage within the range of the number of solar cell modules belonging to each stage. As the number of voltage sources increases, the number of solar cell modules that can compensate the current increases, but the cost and circuit scale increase. That is, both are in a trade-off relationship.

Next, an example of retrofitting the above-mentioned voltage source for current compensation to an existing photovoltaic power generation system will be described. FIG. 8 is a diagram illustrating a configuration example of a small-scale photovoltaic power generation system 500a. The small-scale photovoltaic power generation system 500a is mainly used for residential use. The photovoltaic power generation system 500 a includes a solar cell array 100 and a power conditioner 40. The solar cell array 100 is installed on the roof of a house.

The solar cell array 100 shown in FIG. 8 has the same connection form as the solar cell array 100a shown in FIG. That is, a plurality of series circuits in which a plurality of solar cell modules are connected in series are provided, and the plurality of series circuits are connected in parallel. In the example shown in FIG. 8, a first series in which a 1.1 solar cell module 11, a 1.2 solar cell module 12, a 1.3 solar cell module 13 and a 1.4 solar cell module 14 are connected in series. The circuit and the second series circuit in which the 2.1 solar cell module 21, the 2.2 solar cell module 22, the 2.3 solar cell module 23, and the 2.4 solar cell module 24 are connected in series are parallel. It is a configuration to be connected.

The output wiring of the first series circuit and the output wiring of the second series circuit are bundled in a connection box (not shown) and connected to the power conditioner 40. The power conditioner 40 converts the DC power generated by the solar cell array 100 into AC power. The power conditioner 40 adjusts the amplitude and frequency of the output voltage to a specified range of amplitude and frequency. The power conditioner 40 supplies the generated AC power to a load in the home. Moreover, it can be made to reverse flow to a commercial system.

FIG. 9 is a diagram illustrating a configuration example of the photovoltaic power generation system 500b according to the embodiment in which a voltage source for current compensation is retrofitted to the photovoltaic power generation system 500a illustrated in FIG. Hereinafter, changes between the two will be described.

First, the worker connects the nodes of the corresponding stages of the first series circuit and the second series circuit of the solar cell array 100 by wiring. That is, the worker is between the node between the 1.1 solar cell module 11 and the 1.2 solar cell module 12, and between the 2.1 solar cell module 21 and the 2.2 solar cell module 22. Connect the nodes with wiring. Similarly, a node between the 1.2 solar cell module 12 and the 1.3 solar cell module 13 and a node between the 2.2 solar cell module 22 and the 2.3 solar cell module 23 Connect with wiring. Similarly, a node between the 1.3 solar cell module 13 and the 1.4 solar cell module 14, and a node between the 2.3 solar cell module 23 and the 2.4 solar cell module 24. Connect with wiring. This addition of wiring corresponds to a change from the solar cell array 100a shown in FIG. 1 to the solar cell array 100b shown in FIG.

Next, an AC-DC converter unit 30 is installed as a voltage source for current compensation. The input terminal of the AC-DC converter unit 30 is connected to the output wiring of the power conditioner 40. The AC-DC converter unit 30 has two input terminals. The output terminal of the AC-DC converter unit 30 is connected to the wiring added to the solar cell array 100 by the above-described operation, and the positive side output wiring and the negative side output wiring of the solar cell array 100. Since the number of these wires is the number of series stages + 1, the number of output terminals of the AC-DC converter unit 30 is (the number of series stages + 1). In the example shown in FIG.

FIG. 10 is a diagram showing an internal configuration example of the AC-DC converter unit 30 shown in FIG. The AC-DC converter unit 30 includes a plurality of isolated AC-DC converters connected in cascade. The number of AC-DC converters corresponds to the number of series stages. In the example shown in FIG. 10, the AC-DC converter unit 30 includes a first AC-DC converter 31a, a second AC-DC converter 32a, a third AC-DC converter 33a, and a fourth AC-DC converter 34a.

The output AC voltage of the power conditioner 40 is input to each of the AC-DC converters 31a to 34a. Each of the AC-DC converters 31a to 34a converts the AC voltage into a DC voltage corresponding to the electromotive voltage of one solar module while stepping down the AC voltage. The first AC-DC converter 31a applies the generated DC voltage to both ends of the 1.1 solar cell module 11 and both ends of the 2.1 solar cell module 21 in parallel. Similarly, the second AC-DC converter 32 a applies the generated DC voltage in parallel to both ends of the 1.2 solar cell module 12 and both ends of the 2.2 solar cell module 22. Similarly, the third AC-DC converter 33 a applies the generated DC voltage to both ends of the 1.3 solar cell module 13 and both ends of the 2.3 solar cell module 23 in parallel. Similarly, the fourth AC-DC converter 34 a applies the generated DC voltage to both ends of the 1.4 solar cell module 14 and both ends of the 2.4 solar cell module 24 in parallel. Thereby, the electrical configuration similar to the

solar cell arrays

100d and 100e shown in FIGS. 5 and 6 can be created.

Note that an example in which a DC-DC converter is used in the solar cell array 100e shown in FIG. In the photovoltaic power generation system 500b shown in FIG. 9, a DC-DC converter may be used instead of the AC-DC converter. In that case, the DC-DC converter uses a DC voltage input to the power conditioner 40 as an input voltage.

In a general high voltage DC-DC converter, an input DC voltage is DC-AC converted to generate an AC voltage, the generated AC voltage is transformed with a transformer, and the transformed AC voltage is rectified and smoothed. Output DC voltage is generated. Therefore, if the input voltage is an AC voltage, the first DC-AC conversion can be omitted, and the circuit scale and power loss due to the conversion can be reduced. In view of this point, an example in which an AC-DC converter is used is given in the photovoltaic power generation system 500b shown in FIG. The AC-DC converter may be handled in the same way as a general load, and commercial power may be directly supplied to the AC-DC converter.

FIG. 11 is a diagram illustrating a configuration example of a large-scale photovoltaic power generation system 500c. The large-scale photovoltaic power generation system 500c is mainly used for industrial use. For example, it is installed in an office building, factory, commercial facility, public facility or the like.

The solar cell array 100 shown in FIG. 11 has the same connection form as the solar cell array 100a shown in FIG. That is, a plurality of series circuits in which a plurality of solar cell modules are connected in series are provided, and the plurality of series circuits are connected in parallel. In the example shown in FIG. 11, a series-parallel circuit having 9 serial numbers and 4 parallel numbers is shown.

FIG. 12 is a diagram illustrating a configuration example of a photovoltaic power generation system 500d according to the embodiment in which a voltage source for current compensation is retrofitted to the photovoltaic power generation system 500c illustrated in FIG. Hereinafter, changes between the two will be described.

It is also possible to change the photovoltaic power generation system 500c shown in FIG. 11 to an electrical configuration as shown in FIG. However, when the solar cell array 100 becomes large-scale, the work of installing wirings that cross-connect the nodes between the respective series stages becomes large-scale. Therefore, in the photovoltaic power generation system 500c shown in FIG. 12, the connection form of the solar cell array 100 is changed.

The worker reconnects a series circuit in which a plurality of solar cell modules are connected in series to a parallel circuit, and connects the parallel circuits in series. In the example shown in FIGS. 11 and 12, the 1.1-th solar cell modules 11 to 1.9 solar cell modules 19 connected in series are reconnected to a parallel circuit. Similarly, the 2.1-th solar cell module 21 to the 2.9-th solar cell module 29 connected in series are reconnected to the parallel circuit. Similarly, the 3.1-th solar cell module 31 to the 3.9-th solar cell module 39 connected in series are reconnected to the parallel circuit. Similarly, the 4.1-th solar cell module 41 to the 4.9-th solar cell module 49 connected in series are reconnected to the parallel circuit. The worker connects four newly generated parallel circuits in series. Therefore, the reconnected solar cell array 100 is a series-parallel circuit having a parallel number of 9 and a serial number of 4. Before and after reconnection, the values of the output voltage and output current of the solar cell array 100 change, but the value of the output power multiplied by both does not change.

Next, an AC-DC converter unit 30 is installed as a voltage source for current compensation. The input terminal of the AC-DC converter unit 30 is connected to the output wiring of the power conditioner 40. The AC-DC converter unit 30 has two input terminals. The output terminal of the AC-DC converter unit 30 is connected to each node of a series circuit formed by the above-described four parallel circuits of the solar cell array 100. Since the number of nodes is the number of series stages + 1, the number of output terminals of the AC-DC converter unit 30 is (the number of series stages + 1). In the example shown in FIG.

The AC-DC converter unit 30 shown in FIG. 12 can also be configured as shown in FIG. In the AC-DC converter unit 30 shown in FIG. 12, the number of solar cell modules that one AC-DC converter is in charge of (9 in the example shown in FIG. 12) is large. Therefore, a plurality of AC-DC converters may be installed in parallel for each series stage. For example, two first AC-DC converters 31 a may be connected in parallel to both ends of the 1.1 solar cell module 11 to the 1.9 solar cell module 19. In this case, even if a failure occurs in two of the 1.1 solar cell module 11 to the 1.9 solar cell module 19, the two currents can be compensated by the two first AC-DC converters 31a.

According to the retrofitting method of the voltage source shown in FIG. 12, the work amount of the worker can be reduced compared to the retrofitting method shown in FIG. Therefore, it is suitable for application to a large-scale photovoltaic power generation system 500. The retrofit method shown in FIG. 10 is not limited to the application to the small-scale photovoltaic power generation system 500, and the retrofit method shown in FIG. 12 is not limited to the application to the large-scale photovoltaic power generation system 500. The retrofit method can be applied to the solar power generation system 500 of any scale.

Heretofore, an example in which a voltage source for current compensation is retrofitted to all the solar cell modules included in the solar cell array 100 has been described. Hereinafter, an example in which the voltage source is retrofitted only for a solar cell module in which power generation is incomplete will be described.

FIG. 13 is a diagram illustrating a configuration example of the photovoltaic power generation system 500e according to the embodiment in which a voltage source for current compensation is retrofitted to the photovoltaic power generation system 500c illustrated in FIG. 11 (one of the solar battery modules is broken). is there. In the solar cell array 100 shown in FIG. 13, the 2.8 solar cell module 28 has failed. When a solar cell module breaks down, it is usually replaced with a new one, but the solar cell module may be difficult to obtain due to the end of production.

Therefore, the AC-DC converter unit 30 is installed. The AC-DC converter unit 30 includes one AC-DC converter. The output terminals of the AC-DC converter are connected to both ends of the failed 2.8 solar cell module 28. The AC-DC converter applies a voltage corresponding to the electromotive voltage to both ends of the 2.8 solar cell module 28.

As described above, according to the retrofitting method of the voltage source shown in FIG. 13, the retrofitting method can be installed at a lower cost than the retrofitting method shown in FIG. Also, the amount of work can be reduced because less wiring is required.

FIG. 14 is a diagram illustrating a configuration example of the photovoltaic power generation system 500f according to the embodiment in which a voltage source for current compensation is retrofitted to the photovoltaic power generation system 500c illustrated in FIG. 11 (shadowed on a part of the solar cell module). It is. In the solar cell array 100 shown in FIG. 14, the 4.8 solar cell module 28 and the 4.9 solar cell module 29 are incompletely generated due to the shadow of the tree.

In this case, an AC-DC converter unit 30 including two AC-DC converters is installed. The output terminals of the two AC-DC converters are respectively connected to both ends of the 4.8 solar cell module 48 and both ends of the 4.9 solar cell module 49 where shadows are generated. One AC-DC converter that outputs twice the output voltage is provided, and twice the output voltage is applied to both ends of the 4.8 solar cell module 48 and the 4.9 solar cell module 49 connected in series. May be. The same applies to three or more series.

The occurrence of the shadow may change after the solar cell array 100 is installed. For example, if a high building is erected around after installation, a new shadow is generated. Therefore, a method of installing a converter that becomes an alternative power source for the solar cell module in the shadowed area after the fact is very effective.

FIG. 15 is a diagram showing a state in which a plurality of solar cell modules have failed in the photovoltaic power generation system 500c shown in FIG. In the photovoltaic power generation system 500g shown in FIG. 15, three of the 1.9 solar cell module 19, the 2.2 solar cell module 22, and the 3.5th solar cell module 35 are out of order. It is conceivable to connect an AC-DC converter to each end of each solar cell module in the manner shown in FIGS. Hereinafter, a method capable of simplifying the routing of the wiring will be described.

FIG. 16 is a diagram illustrating a configuration example (series type) of a photovoltaic power generation system 500h according to the embodiment in which a voltage source for current compensation is retrofitted to the photovoltaic power generation system 500g illustrated in FIG. In the photovoltaic power generation system 500h shown in FIG. 16, three faulty solar cell modules are collected in one place. Specifically, the worker replaces the broken 2.2 solar cell module 22 with the normal 1.7 solar cell module 17. Further, the failed 3.5th solar cell module 35 and the normal 1.8th solar cell module 18 are exchanged. Thus, the failed solar cell modules can be combined into one series circuit formed by the 1.7 solar cell module 17, the 1.8th solar cell module 18, and the 1.9 solar cell module 19. it can.

The AC-DC converter unit 30 shown in FIG. 16 includes one AC-DC converter that outputs three times the output voltage. The output terminal of the AC-DC converter is connected to both ends of the series circuit. The AC-DC converter applies a voltage corresponding to the electromotive voltage of three solar cell modules connected in series to both ends of the series circuit.

FIG. 17 is a diagram illustrating a configuration example (parallel type) of the photovoltaic power generation system 500i according to the embodiment in which a voltage source for current compensation is retrofitted to the photovoltaic power generation system 500g illustrated in FIG. Also in the photovoltaic power generation system 500i shown in FIG. 17, three faulty solar cell modules are collected in one place. Specifically, the worker replaces the failed 2.2 solar cell module 22 with the normal 2.9 solar cell module 29. Also, the failed 3.5th solar cell module 35 and the normal 3.9 solar cell module 39 are exchanged. Furthermore, both ends of the 1.9 solar cell module 19, the 2.9 solar cell module 29, and the 3.9 solar cell module 39 are connected in parallel by wiring. Thereby, the failed solar cell modules can be combined into one parallel circuit formed by the 1.9 solar cell module 19, the 2.9 solar cell module 29, and the 3.9 solar cell module 39. it can.

The AC-DC converter unit 30 shown in FIG. 17 includes three AC-DC converters connected in parallel. The common output terminals of the three AC-DC converters connected in parallel are connected to both ends of the parallel circuit. The three AC-DC converters connected in parallel make up for the power generation current of three solar cell modules connected in parallel.

As described above, according to the retrofitting method shown in FIGS. 16 and 17, the wiring operation can be simplified by collecting a plurality of faulty solar cell modules in one place.

The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there.

The invention according to the present embodiment may be specified by the items described below.

[Item 1]
A solar cell array in which a plurality of solar cell modules are connected in series and parallel in a matrix,
A solar cell array, wherein a voltage source is connected to both ends of at least one of the plurality of solar cell modules.

According to this aspect, it is possible to suppress a decrease in the output power of the solar cell array when at least one solar cell module stops power generation due to a shadow or the like.

[Item 2]
2. The solar cell array according to item 1, wherein the voltage source is connected in parallel to each parallel stage of a series-parallel circuit in which the plurality of solar cell modules are connected in series and parallel.

According to this aspect, even when any of the solar cell modules constituting the solar cell array stops generating power, it is possible to compensate for the power reduction due to the stop of power generation.

[Item 3]
The voltage source is a step-down circuit;
The output terminals of the step-down circuit connected to each parallel stage are connected in series,
The input terminals of the plurality of step-down circuits connected in series are connected between the positive output terminal and the negative output terminal of the solar cell array,
3. The solar cell array according to item 2, wherein an output voltage of the solar cell array is used as a power supply voltage for the plurality of step-down circuits.

According to this aspect, a self-contained system that does not require an external power source can be constructed.

[Item 4]
A solar cell array in which a plurality of solar cell modules are connected in series and parallel;
A voltage source connected to at least one end of each of the plurality of solar cell modules;
A photovoltaic power generation system comprising:

According to this aspect, a solar power generation system with stable output power can be constructed.

[Item 5]
The voltage source is connected to both ends of a solar cell module in which power generation is incomplete among a plurality of solar cell modules constituting the solar cell array after the solar cell array is installed. 4. The photovoltaic power generation system according to 4.

According to this aspect, a low-cost system can be constructed by connecting a voltage source only to a solar cell module that needs assistance.

[Item 5]
A power conditioner that converts the DC power generated by the solar cell array into AC power;
The voltage source is an AC-DC converter, and the AC-DC converter applies a DC voltage generated using an AC voltage output from the power conditioner as an input voltage to both ends of the solar cell module. Item 6. The photovoltaic power generation system according to item 4 or 5.

100a, 100b, 100c, 100d, 100e, 100f solar cell array, 11th 1.1 solar cell module, 12th 1.2 solar cell module, 21st 2.1 solar cell module, 49th 4.9 solar cell module , I current source, D diode, Rs series resistance, Rsh parallel resistance, E1 first voltage source, E2 second voltage source, E3 third voltage source, 31 first DC-DC converter, 32 second DC-DC converter, 33 th 3DC-DC converter, 30 AC-DC converter unit, 31a 1st AC-DC converter, 32a 2nd AC-DC converter, 33a 3rd AC-DC converter, 34a 4th AC-DC converter, 500a, 500b,

500c

500d, 500e, 500f, 500g, 500h, 500i solar power system.

The present invention can be applied to a solar power generation system using a solar cell array in which a plurality of solar cell modules are connected in series and parallel.

Claims

A solar cell array in which a plurality of solar cell modules are connected in series and parallel in a matrix,
A solar cell array, wherein a voltage source is connected to both ends of at least one of the plurality of solar cell modules.
The solar cell array according to claim 1, wherein the voltage source is connected in parallel to each parallel stage of a series-parallel circuit in which the plurality of solar cell modules are connected in series and parallel.
The voltage source is a step-down circuit;
The output terminals of the step-down circuit connected to each parallel stage are connected in series,
The input terminals of the plurality of step-down circuits connected in series are connected between the positive output terminal and the negative output terminal of the solar cell array,
The solar cell array according to claim 2, wherein an output voltage of the solar cell array is used as a power supply voltage for the plurality of step-down circuits.
A solar cell array in which a plurality of solar cell modules are connected in series and parallel;
A voltage source connected to at least one end of each of the plurality of solar cell modules;
A photovoltaic power generation system comprising:
The voltage source is connected to both ends of a solar cell module incompletely generating power among a plurality of solar cell modules constituting the solar cell array after the solar cell array is installed. Item 5. A photovoltaic power generation system according to item 4.
A power conditioner that converts the DC power generated by the solar cell array into AC power;
The voltage source is an AC-DC converter, and the AC-DC converter applies a DC voltage generated using an AC voltage output from the power conditioner as an input voltage to both ends of the solar cell module. The photovoltaic power generation system according to claim 4 or 5.