JP2002262461A - Solar power generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar power generating device which derives a maximum power as a system by individually chopper-controlling each solar cell panel which is divided into a plurality of pieces. SOLUTION: The solar power generating device has the solar cell panel divided into a plurality of blocks, output control devices which are respectively disposed on every divided solar cell panel and makes respectively the maximum output control, and diodes each of which is serially connected to the output line of each control device and prevents crosscurrent among the respective outputs, and a bus voltage is gained by parallel-connecting the diodes on the output side of the respective diodes. The solar power generating device has the solar cell panel divided into the plurality of blocks, the output control devices which are respectively disposed on every divided solar cell panel and makes respectively the maximum output control, and bypass diodes each of which is parallel-connected to the output line of each control device, and the sum of the voltages of each output control device is obtained by serially connecting the output line of the output control devices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic power generator using a solar cell panel divided into a plurality of blocks.

[0002]

2. Description of the Related Art Unlike other natural energies, solar power generation using solar cells can be easily installed on the roof or wall of a building, and there is no need to worry about noise or other pollution.
It is expected to be an attractive power generation system. In recent years, it has become possible to perform reverse power flow operation, and when performing photovoltaic power generation in ordinary households, it is common to use a grid connection inverter to connect to a commercial AC power supply.

[0003] An example of the characteristic of the generated voltage versus the generated power of a solar cell is a curve as shown in FIG. 4 when the horizontal axis is the generated voltage, the vertical axis is the generated power, and the sunlight intensity is a parameter, as shown in FIG. The maximum power Pmax changes depending on the intensity of sunlight. Therefore, as a method for increasing the power generation efficiency, a maximum power point tracking control method (Maximum Power Point Tr Tr) in which the maximum power Pmax is always controlled to be extracted
acting (hereinafter, MPPT control method), and this method is usually employed.

[0004] An actual system for extracting predetermined electric power by a photovoltaic power generator has a configuration as shown in FIG. That is, a plurality of solar cell panels 11, 1
.. 1n are connected in parallel, and connected to the commercial AC power supply 7 via the inverting device 2 composed of the step-up chopper 80, the inverter 5, and the filter 6 to perform system interconnection.

[0005]

However, in the above-mentioned method, since a plurality of solar cell panels 11, 12,..., 1n are installed on the roof or wall of a building, there is a case where the solar cell panels 11, 12,. Or, the angle at which the panel faces the sun is different, so that the sunlight intensity received by the panel often does not become the same. If the solar high intensity received by each panel is different, the open power generation voltage slightly differs as shown in FIG. 4, but the maximum generated power Pmax is greatly different,
The generated voltage that gives the maximum generated power Pmax also differs.

[0006] For example, a solar cell panel receiving a solar light intensity of 1.0 kW / m2 has a maximum power Pa at a point a.
And the generated voltage at this time is Va. Also, 0.
The solar panel receiving the sunlight intensity of 4 kW / m2 gives the maximum power Pb at the point b, and the generated voltage at this time is Vb. Therefore, when operating with one boost chopper, if solar cell panels receiving different sunlight intensities are connected in parallel, the maximum power will be a voltage close to the generated voltage of a panel with a large internal impedance and a small maximum power. Has a problem that only smaller power than the maximum power can be extracted, and the power generated by the entire system is reduced.

The present invention has been made under such a background, and a solar power generation apparatus capable of extracting maximum power as a system by individually controlling a chopper for each of a plurality of divided solar cell panels. The purpose is to provide.

[0008]

According to the first aspect of the present invention, there is provided a solar cell panel divided into a plurality of blocks, an output control device provided for each of the divided solar cell panels, and each of which controls a maximum output. A diode that is connected in series to an output line of the control device and that prevents a cross current between respective outputs, and that is connected in parallel on the output side of the diode to obtain a bus voltage. I will provide a.

According to the present invention, the solar cell panel is divided into a plurality of blocks, the maximum output is individually controlled, and the common bus voltage is applied to the solar cell panel via the cross current prevention diode. The maximum output can be obtained as a system even if the values are different.

According to a second aspect of the present invention, there is provided a solar cell panel divided into a plurality of blocks, an output control device provided for each of the divided solar cell panels, for performing maximum output control, and an output of the output control device. And a bypass diode connected in parallel to a line, wherein an output line of the output control device is connected in series to obtain a sum voltage of the output control devices.

According to the present invention, it is possible to individually control the outputs of the divided solar cell panels to extract the maximum output and obtain the sum of the respective outputs. Even when performing this, it is not always necessary to use a boosting chopper.

According to a third aspect of the present invention, in the solar power generation device according to the first or second aspect, the solar cell panel is an amorphous silicon solar cell having no bypass diode.

According to the present invention, in an amorphous silicon solar cell having no bypass diode, the influence of solar radiation intensity is strong, but even in such a case, a maximum output can be obtained as a system.

According to a fourth aspect of the present invention, in the photovoltaic power generator according to the first or third aspect, the output control device performs control to obtain the common bus voltage by a step-up chopper. .

According to the present invention, the output of each solar cell panel can be effectively taken out by controlling the DC voltage so that the common bus voltage is obtained by using the step-up chopper. Obtainable.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a solar power generation device according to one embodiment of the present invention. In this figure, reference numerals 11, 12,..., 1n denote solar cell panels divided into a plurality of sheets, and outputs thereof are connected to boosting choppers 21, 22,. The outputs of the boost choppers 21, 22,..., 2n are commonly connected via diodes 31, 32,.
This is the input of the inverter 5. The output of the inverter 5 is connected to a commercial AC power supply 7 via a filter 6 to perform a system interconnection operation.

FIG. 2 shows the boost choppers 21 and 22 of FIG.
... is a connection diagram in which a 2n portion is formed into a specific circuit. In this figure, a boost chopper 21 includes a DC current detector 211 for detecting a current of a solar cell panel, a capacitor 212, a reactor 213, and an IGBT 21 for performing a switching operation.
4 and a control device 215. Since the boost choppers 22,..., 2n have the same configuration, these components are not denoted by reference numerals.

Next, the operation of the photovoltaic power generator according to one embodiment of the present invention will be described with reference to FIGS. 1, 2 and FIG. Solar cell panel 1 divided into a plurality
Because 1, 12, ..., 1n are installed on the roof or wall of a building, there are objects that shade the neighboring buildings, or the solar panels face different angles at which the solar panels face the sun. In many cases, the sunlight intensity received by the lights does not become the same. When the solar high intensity received by each solar cell panel is different, the open power generation voltage is slightly different as shown in FIG. 4, but the maximum generated power Pmax is greatly different,
The generated voltage that gives the maximum generated power Pmax also differs.

For example, a solar cell panel receiving a sunlight intensity of 1.0 kW / m 2 has a maximum power Pa at a point a.
And the generated voltage at this time is Va. Also, 0.
The solar panel receiving the sunlight intensity of 4 kW / m2 gives the maximum power Pb at the point b, and the generated voltage at this time is Vb. Therefore, in the conventional method in which solar panels receiving different sunlight intensities are connected in parallel, and converted into AC power by one inverter to perform system interconnection, the maximum power generated by the solar panel is large. The voltage becomes close to the generated voltage Va of the panel having a small internal impedance, and only a power smaller than the maximum power can be taken out from the panel having a small maximum power.

Therefore, as shown in FIG. 1 or FIG. 2, step-up choppers 21, 22,..., 2n are provided for the plurality of divided solar cell panels 11, 12,. Control is performed individually.
The step-up chopper 21 controls the DC output voltage by detecting the current of the solar cell panel 11 and the voltage of the capacitor 212 by the DC current detector 211 with the chopper control device 215 and controlling the switching of the IGBT 214.

Under the control of the chopper controller 215, I
While the GBT 214 is ON, the reactor 213
Current flows through the IGBT 214 through the
Energy is stored in 3. Next, when the IGBT 214 is turned off, a back electromotive force is generated in the reactor 213,
The sum of the voltage due to the back electromotive force and the voltage of the capacitor 212 becomes the output voltage, and the current that has just passed through the reactor 213 is output. Therefore, the chopper control device 2
By changing the ON duty of the IGBT 214 by the control of No. 15, the output of the solar cell panel 11 is controlled while the output of the inverter 5 and the filter 6 is controlled to a voltage suitable for the system interconnection with the commercial power source 7 by controlling the DC output voltage. Can be maximized.

By controlling the solar cell panels 12,..., 1n in the same manner as the solar cell panel 11, the operating point of each solar cell panel can be set at the maximum output point, and the power generation stress of each solar cell Can be maximized.

Next, another embodiment of the present invention will be described. FIG. 3 is a block diagram showing a configuration of a solar power generation device according to another embodiment of the present invention. In this figure, the solar cell panel 11 is connected to a chopper 81, and the solar cell panel 12 is connected to a chopper 82. The outputs of the choppers 81 and 82 are connected in series,
The sum of the output voltages is input to the inverter 5.

Here, the choppers 81 and 82 maximize the solar cell panels 11 and 12, respectively, and
Control is performed so that the sum of the outputs of the choppers 81 and 82 becomes a voltage suitable for system interconnection. In this case, the chopper may be a step-down chopper instead of a step-up chopper, and may be any as long as it has a voltage suitable for system interconnection. In particular, in a method of connecting a plurality of solar cell panels using an amorphous solar cell without a bypass diode in series, the power generation stress of each solar cell panel can be maximized according to this embodiment.

The operation of one embodiment of the present invention has been described in detail with reference to the drawings. However, the present invention is not limited to this embodiment, and a design change or the like within a range not departing from the gist of the present invention. The present invention is also included in the present invention. For example, the switch element used in the chopper is not limited to the IGBT, but may be another element. Further, the number of solar cell panels in other embodiments is not limited to two, but may be three or more.

[0026]

As described above, according to the first aspect of the present invention, a chopper is provided for each of a plurality of divided solar cell panels, and the choppers are individually controlled to obtain a maximum output. Since the bus voltage is established by connecting in parallel via a cross current prevention diode, the maximum output can be obtained as a system even when the solar radiation intensity between the solar cell blocks is different, and the system interconnection can be performed stably. The effect that can be obtained is obtained. In addition, by controlling the choppers provided for each solar cell individually, interference between the choppers can be prevented, and an effect that a stable operation can be performed can be obtained.

According to the second aspect of the present invention, a chopper is provided for each of a plurality of divided solar cell panels, and the choppers are individually controlled to obtain a maximum output. Since the voltage is set, it is possible to obtain an effect that it is not always necessary to use the step-up chopper when the system is connected to the commercial power supply.

[Brief description of the 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 connection diagram in which a boost chopper portion of FIG. 1 is formed into a specific circuit;

FIG. 3 is a block diagram showing a configuration of a solar power generation device according to another embodiment of the present invention.

FIG. 4 is a characteristic diagram showing output characteristics of the solar cell panel.

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 panels 21, 22,... 2n step-up chopper 211. ... 3n ... diode 4 ... capacitor 5 ... inverter 6 ... filter 7 ... commercial AC power supply 81, 82 ... chopper 91, 92 ... capacitor

Continued on the front page (72) Inventor Hiroyuki Otake 3-1-1 Asahimachi, Nishibiwajima-cho, Nishi-Kasugai-gun, Aichi Prefecture Inside the Cooling Business Division of Mitsubishi Heavy Industries, Ltd. 1 F-term (Ref.) 5M066 CA08 DA08 HB06 JB04 5H420 BB03 BB12 BB14 CC03 CC09 DD09 DD10 EA10 EA20 EA40 EA48 EB04 FF03 FF04 FF22

Claims (4)

[Claims] 1. A solar cell panel divided into a plurality of blocks, an output control device provided for each of the divided solar cell panels and performing maximum output control, and connected in series to an output line of the control device. And a diode for preventing a cross current between the outputs of the photovoltaic devices, and a bus voltage is obtained by connecting in parallel at the output side of the diode. 2. A solar cell panel divided into a plurality of blocks, an output control device provided for each of the divided solar cell panels and performing a maximum output control, and a bypass connected in parallel to an output line of the output control device. A photovoltaic power generator comprising: a diode; and connecting the output lines of the output control devices in series to obtain a sum voltage of the output control devices. 3. The photovoltaic power generator according to claim 1, wherein the solar cell panel is an amorphous silicon solar cell having no bypass diode. 4. The photovoltaic power generation device according to claim 1, wherein the output control device performs control for obtaining the common bus voltage by a step-up chopper.