JP2003134667A - Photovoltaic power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photovoltaic power generation device capable of MPPT control over all solar cell panels even if power generation characteristics varies among the solar cell panels. SOLUTION: There are provided a plurality of blocks of solar cell panels, a junction box wherein the output of each block of solar cell panels is separately converted into a DC voltage, to provide a common prescribed voltage which is collected, and a power conditioner which inversely converts the DC output collected in the junction box into an AC power, so as to perform linkage operation with the power system. In DC voltage conversion, a step-up chopper is follow-up controlled so that the output of each block of solar cell panels comes to be a maximum power point. The power conditioner comprises an inverter which inversely converts the DC output of the junction box into an AC power of such voltage and frequency as to link with the power system, and a system linkage protecting function which releases the linkage if an abnormal current or voltage occurs during linkage operation for protection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar power generation device, and more particularly to a technique for effectively taking out the output of a plurality of blocks of solar cell panels to perform interconnection operation with a power system.

[0002]

2. Description of the Related Art Photovoltaic power generation using solar cells, unlike other power generation systems using natural energy, can be easily installed on the roof or wall of a building, and there is no concern about noise or other pollution. It has come to be expected as a pollution power generation system. In recent years, it has become possible to perform interconnection operation with the electric power system, and when performing solar power generation in general households, it is common to use a grid interconnection inverter to perform grid interconnection with a commercial AC power source. .

The actual system of the solar power generator is shown in FIG.
The configuration shown in is adopted. That is, the outputs of the plurality of blocks of solar cell panels 11, 12, ... 1n are connected and collected via the backflow prevention diodes 201, 202, ... 20n in the junction box 20 installed outdoors. Maximum power point tracking control (Maximum Power Point Tracking Control) by the boost chopper 30 in the power conditioner 30 installed indoors.
(ower Point Tracking, hereinafter referred to as MPPT control), boosts the voltage to a predetermined DC voltage, converts the AC power into AC power of a frequency and voltage that can be interconnected by the inverter 30, and interconnects with the power system 5 to which the load 4 is connected. Drive. The junction box 20 and the power conditioner 30 shown in FIG.
Then, the switches and the like are omitted, and the protection function and the like are not shown.

[0004]

However, in the above-mentioned method, when a plurality of blocks of solar cell panels are installed on the roof surface in different directions or when solar cell panels having different power generation characteristics are used, the solar cells as shown in FIG. The optimum operating voltage differs for each battery panel, and the battery voltage is equalized by the backflow prevention diode, so that there is a problem that optimum MPPT control cannot be performed.

Further, MPPT control can be performed by installing solar cell panels having the same characteristics in the same position direction, but the effect of shadows caused by trees and the like must be eliminated, and the installation location is restricted. There were challenges.

The present invention has been made under such a background, and even if a plurality of blocks of solar cell panels are installed on the roof surfaces in different directions or even if the solar cell panels having different power generation characteristics are used, It is an object of the present invention to provide a photovoltaic power generation device that can perform MPPT control on a battery panel.

It is another object of the present invention to provide a solar power generation device in which the connection box installed outdoors is of a high function type and the power conditioner installed indoors is of a single function type, and the equipment configuration balance is improved. .

[0008]

According to a first aspect of the present invention, a solar cell panel having a plurality of blocks and installed outdoors,
The output of each block of the solar cell panel is individually converted into a DC voltage to obtain a common predetermined voltage, and then a connection box for collecting current is installed indoors, and the DC output of the collected connection box is converted into AC power. Provided is a solar power generation device, which is equipped with a power conditioner that performs reverse conversion and is operated in an interconnected manner with a power system.

According to the present invention, in a junction box installed outdoors, the outputs of a plurality of blocks of solar cell panels are individually converted into direct-current voltages to obtain a predetermined common voltage, and then current is collected to obtain a common predetermined voltage. Since the power conditioner installed indoors converts the power into AC power for interconnection operation with the power system, even if the solar radiation intensity between the solar cell blocks is different or the solar cell panels have different characteristics, the system As always you can get a high output.

According to a second aspect of the present invention, in the solar power generation device according to the first aspect, the DC voltage conversion is performed so that the output of each block of the solar cell panel becomes a maximum power point by a step-up chopper. It is characterized by performing follow-up control.

According to the present invention, in a junction box installed outdoors, the output of a plurality of blocks of solar cell panels is individually MPPT-controlled by using a step-up type chopper to control a DC voltage so as to have a common predetermined voltage. After that, since the current is collected, even if the solar cell panels have different solar intensities or have different characteristics, the output of each solar cell panel can be effectively taken out, and the system is high. You can get the output.

According to a third aspect of the present invention, in the solar power generation device according to the first or second aspect, the power conditioner is an alternating current of a voltage and a frequency at which the DC output of the junction box can be connected to a power system. It is characterized by including an inverter that reversely converts the electric power and a grid interconnection protection function that releases and protects the grid when an abnormal current or an abnormal voltage is generated during interconnection operation.

According to the present invention, after the voltage is converted in the junction box, the collected DC power is inversely converted into AC power having a voltage and a frequency that can be interconnected with the power system in the power conditioner installed indoors. Since the power conditioner does not have a step-up chopper, only the inverter and the grid interconnection protection function are stored, and the burden on the power conditioner installed indoors is eliminated. Can be reduced.

The invention described in claim 4 is the invention according to claims 1 to 3.
In the solar power generation device described in any one of 1 above, the connection box installed outdoors is a high-performance type, and the power conditioner installed indoors is a single-function type, so that the device configuration balance is improved. I will provide a.

According to this invention, the junction box installed outdoors has a boosting chopper function, and the output of the solar cell panels of a plurality of blocks is MPPT-controlled to convert it into a direct current voltage, and then the high-performance junction box collects electricity. Since the power conditioner installed indoors is a single-function power conditioner that has only an inverter that converts to AC power and performs interconnection operation with the power system, and a grid interconnection protection function for interconnection operation. Since the size of the power conditioner can be reduced and heat generation due to loss can be suppressed, the balance of the device configuration of the entire device can be improved, and low cost and miniaturization can be realized.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a solar power generation device according to an embodiment of the present invention. In this figure, reference numerals 11, 12, ... 1
n is a solar cell panel, and the outputs thereof are connected to the input terminals of the boost choppers 21, 22, ... 2n of the junction box 2, respectively.

The output side of the step-up choppers 21, 22, ..., 2n is connected to form one output, which is input to the inverter 31 of the power conditioner 3. The inverter 31 inversely converts the DC power into AC power and outputs the AC power to perform an interconnection operation with the power system 5 to which the load 4 is connected. Since the system interconnection protection function 32 performs interconnection, the voltage, current, and
Although the protection is performed by detecting the frequency or the temperature, the detailed functions and the switches and the like of each part for protection are omitted from the description and illustration.

Next, referring to FIGS. 2 to 4, the characteristics of the solar cell panels 11, 12, ... 1n actually installed and the step-up choppers 21, 22, ..
The control of 2n and the inverter 31 will be described. FIG. 2A shows solar cell panels 11, 12, 13 having the same characteristics.
And 14 are installed on the east, north, west, and south roof surfaces of the house with a parquet roof. Further, as shown in FIG. 2B, the angles formed by the respective roof surfaces with the horizontal plane are 25 °.

FIG. 3 is a diagram showing the generated voltage-output power characteristics of the solar cell panel installed on each roof surface shown in FIG. This characteristic diagram shows the output power characteristic around 12:00 (noon). The maximum output power is the maximum power P14 of the output power P14 of the solar cell panel 14 installed on the south side.
0 is the largest, the maximum power P120 of the output power P12 of the solar cell panel 12 installed on the north side is the smallest, and the maximum power of the output power P11 and P13 of the solar cell panels 11 and 13 installed on the east side and the west side. P110 and P130 show intermediate values.

As can be seen from FIG. 3, since the respective solar cell panels have different voltages when outputting the maximum power, the MPPT control is individually performed by the boost chopper for each solar cell panel as shown in FIG. , Inverter 3
By boosting the voltage from 1 to a common predetermined voltage for outputting 200 V AC, it is possible to perform control such that the system always obtains the maximum power.

FIG. 4 is a diagram showing the transition of the maximum power output by the solar cell panel installed on each roof surface shown in FIG. 2 with time. In this figure, the output P110 of the solar cell panel 11 installed on the east side is about 11:30, and the maximum power P1100 is obtained. Similarly, the output P140 of the solar panel 14 installed on the south side is maximum power P1400 at around 13:00, and the solar panel 1 installed on the west side
The output P130 of 3 is the maximum power P130 around 14:00.
0 has been obtained. The output P120 of the solar cell panel 12 installed on the north side is the maximum power P1 around 13:00.
Although 200 is obtained, the maximum power value P1200 is smaller than the maximum power value of the solar cell panel installed on the other surface, and the output characteristics are relatively broad due to the influence of scattered light.

Booster choppers 21 and 2 of the junction box 2 of FIG.
2 ... 2n performs MPPT control so as to respectively obtain the electric power obtained at the same time by each solar cell panel, and the total maximum electric power is obtained by the power conditioner 3
To the inverter 31 to perform the interconnection operation with the power system 5.

The operation of one embodiment of the present invention has been described above in detail with reference to the drawings. However, the present invention is not limited to this embodiment, and the design is within the scope of the present invention. The present invention includes modifications and the like. For example,
In the above embodiment, the case where the solar cell panels having the same characteristics are installed on different roof surfaces has been described.
The present invention is not limited to solar cells having the same characteristics,
The solar cell panels having different characteristics may be mixed. Therefore, an amorphous solar cell and a crystalline solar cell can be mixed and used. Further, even when the direct light of the solar cell panel does not reach due to the shadow of the tree, optimum control can always be performed.

[0024]

As described above, according to the present invention, the following effects can be obtained. According to the invention of claim 1, in the connection box installed outdoors, the outputs of the solar cell panels of the plurality of blocks are individually converted into direct-current voltages to have a predetermined common voltage, and then the current is collected to have a common predetermined voltage, Since the power conditioner installed indoors converts the power into AC power for interconnection operation with the power system, even if the solar radiation intensity between the solar cell blocks is different or the solar cell panels have different characteristics, the system As always you can get a high output.

According to the second aspect of the present invention, in the junction box installed outdoors, the output of the solar cell panels of a plurality of blocks is individually controlled by MPPT by using the step-up type chopper so that the output voltage becomes a common predetermined voltage. Since the current is collected after controlling the voltage, even if the solar radiation intensity between the solar cell blocks is different or even the solar cell panels have different characteristics, the output of each solar cell panel can be effectively extracted.
High output can be obtained as a system.

According to the third aspect of the present invention, after the voltage is converted in the junction box, the collected DC power is AC power having a voltage and a frequency that can be connected to the power system in the power conditioner installed indoors. Since the power conditioner does not have a step-up chopper and only the inverter and the grid interconnection protection function are stored, the power conditioner installed indoors The burden on the user can be reduced.

According to the invention of claim 4, the junction box installed outdoors has a step-up chopper function, and the output of a plurality of blocks of solar cell panels is controlled by MPPT to convert the voltage into a direct current, and then the power is collected. As a function connection box, the power conditioner installed indoors is an inverter that converts to AC power and operates in conjunction with the power system, and a single-function power conditioner that has only a system interconnection protection function for interconnection operation. Therefore, the size of this power conditioner can be reduced and heat generation due to loss can be suppressed, so that the balance of the device configuration of the entire device can be improved, and low cost and miniaturization can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a solar power generation device according to an embodiment of the present invention.

FIG. 2 is a diagram showing solar cell panels installed on each side of a roof of a building.

FIG. 3 is a diagram showing output characteristics of the solar cell panel of FIG.

FIG. 4 is a diagram showing changes in output characteristics of the solar cell panel of FIG. 2 depending on time.

FIG. 5 is a block diagram showing a configuration of a solar power generation device according to a conventional technique.

[Explanation of symbols]

11, 12, ... 1n ... Solar cell panel 2 ... Connection box 20 ... Connection box 201, 202, ... 20n ... Diode 21, 22, ... 2n ... Step-up chopper 3 ... Power conditioner 30 ... Power conditioner 301 ... Booster chopper 302 ... Inverter 31 ... Inverter 32 ... Grid connection protection function 4 ... load 5 ... Power system

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5F051 JA07 KA04 KA05 KA10                 5G066 HA13 HA30 HB06                 5H420 BB03 BB14 CC03 DD03 DD09                       EB04 EB09 EB10 EB39 KK06                       KK10

Claims (4)

[Claims] 1. A solar cell panel having a plurality of blocks, a connection box which is installed outdoors, and which individually collects the output of each block of the solar cell panel to convert it into a common predetermined voltage and then collects the current. A solar power generation device, which is installed indoors and is provided with a power conditioner that reversely converts the direct current output of the connection box that has been collected into alternating current power, and performs interconnection operation with an electric power system. 2. The photovoltaic power generation device according to claim 1, wherein the DC voltage conversion is controlled by a step-up chopper so that the output of each block of the solar cell panel becomes a maximum power point. . 3. The inverter for converting the DC output of the junction box into AC power having a voltage and frequency capable of being connected to an electric power system, and an abnormal current or an abnormal voltage during the interconnection operation. The photovoltaic power generation device according to claim 1 or 2, further comprising a grid interconnection protection function that releases the interconnection and protects it. 4. The equipment configuration balance is improved by making the junction box installed outdoors a high-performance type and the power conditioner installed indoors a single-function type. Or the described solar power generator.