JPH0846231A - Solar generator system - Google Patents

Abstract

PURPOSE:To obtain the maximum power of all solar cell modules constituting a solar cell array. CONSTITUTION:In a solar generator system with a solar cell array constituted by connecting a plurality of solar cell modules 1 in parallel and an inverter 7 converting DC power output from the solar cell array into AC power and supplying load with AC power, a voltage regulator 8 adjusting DC voltage so that DC voltage output to the inverter 7 from each solar cell module 1 is equalized is mounted among each solar cell module 1 configuring the solar cell array and the inverter 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell power generation system which receives power from a solar cell which receives sunlight to generate power.

[0002]

2. Description of the Related Art In a solar cell power generation system, direct current power generated from a solar cell is converted into alternating current power of 50 Hz or 60 Hz, and this alternating current power is supplied to electric equipment operated by commercial alternating current power. There is.

For example, in a private residence, a plurality of solar cells are arranged on the roof of the building, and the DC power generated by the solar cells receiving sunlight is converted into AC power having the same frequency as the commercial frequency. The AC power is converted and supplied to electric equipment through a commercial distribution line system. Also,
When the power generated by the solar cells is low, the commercial power distribution system compensates for the shortage of commercial power to enable stable operation of electrical equipment.

By the way, when a solar cell is installed on the roof of a house, the shape of the surface of the roof on which the solar cell is placed is not always the shape obtained by combining the standard rectangular dimensions of the solar cell. In many cases, the left and right ends of each of them have an inclined trapezoidal shape. In addition, there are restrictions on the arrangement of solar cells depending on the roof design such as the installation of skylights.

9 and 10 show an example of a state in which solar cell modules are arranged on the roof of such a house. In FIG. 9, the solar cell modules 1 are arranged on the roof of the house 3 whose both ends are trapezoidal.

Further, in FIG. 10, a plurality of types of solar cell modules 1 having different dimensions are arranged on the roofs of the first and second floors of a two-story house 3.
As can be seen from FIGS. 9 and 10, in order to maximize the area of the roof of the house and arrange as many solar cell modules 1 as possible, a plurality of solar cell modules 1 may be arranged according to the individual shapes of the roof. It is necessary to prepare size and shape solar cells and use them in combination.

On the other hand, the solar cell module 1 is provided with a terminal for taking out a DC output on the back surface side as shown in FIG. The inside of the solar cell module 1 is configured by connecting a plurality of solar cells 2 in series as shown in FIG.

A plurality of solar cell modules 1 having such a structure are connected in series to form a string, and a plurality of strings are connected in parallel to use the whole as a solar cell array.

The output voltage of the solar cell array is controlled by the inverter so as to reach the maximum output voltage value ΣV (Pmax) at which the solar cell array outputs maximum electric power under constant solar radiation.

Here, when a plurality of types of solar cell modules according to the shape of the roof are combined and used as a solar cell array, the total ΣV (Pmax) of the solar cell module groups in each string connected in series is made uniform. Therefore, a solar cell module having a high V (Pmax) and a solar cell module having a low V (Pmax) are appropriately selected, and are combined in series so that the sum of them is approximately ΣV (Pmax).

FIG. 13 shows a connection configuration example of solar cell modules in a conventional solar cell power generation system. In FIG. 13, V (Pmax) of the solar cell module 1
ΣV (Pmax) of each solar cell string, which is the sum of the above, does not necessarily become equal to each other in the solar cell array, and has a certain width.

Such solar cell strings are connected in parallel with each other through the backflow prevention diode 4 in series, and the output of this parallel circuit is input to the inverter 7 through the switch 5. In this case, the backflow prevention diode 4
The switch 5 and the switch 5 are housed in a connection box 6.

The inverter 7 adjusts the DC voltage input through the backflow prevention diode 4 and the switch 5 of the connection box 6 to ΣV (Pmax), converts the AC voltage to AC, and outputs the AC voltage to the power distribution system.

However, in the solar cell power generation system having such a structure, the output voltage of the solar cell string varies depending on the characteristics of the modules of the solar cell, the shadow of the solar radiation, and the like. When connected in parallel to form a solar cell array, not all of the solar cell modules in each solar cell string can operate at the maximum power point.

The output voltage of the solar cell string is
Although they are arranged so as to be almost equal in advance, if there is a solar cell string lower than the voltage corresponding to ΣV (Pmax) of the entire solar cell array due to the effect of partial shadow, the backflow prevention diode 4 in series with this has a reverse polarity. Biased, the output of that solar cell string is turned off and the inverter cannot be powered.

[0016]

Thus, a solar cell array in which solar cell strings in which solar cell modules are connected in series are connected in parallel to form a solar cell array, and the DC output power thereof is converted into AC power by an inverter In the power generation system, multiple types of solar cell modules are prepared according to the shape of the roof of the house, etc., and these are selected and arranged appropriately, so if the output voltage of each solar cell module is not uniform, It is difficult to obtain the maximum power of all solar cell modules.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solar cell power generation system capable of obtaining the maximum power of all the solar cell modules constituting the solar cell array. .

[0018]

In order to achieve the above-mentioned object, the present invention constitutes a solar cell power generation system by the following means. The invention corresponding to claim 1 is
A solar cell power generation system including a solar cell array configured by connecting a plurality of solar cell modules in parallel, and an inverter that converts DC power output from the solar cell array into AC power and supplies the AC power to a load. In the above, a voltage adjusting means is provided between each solar cell module forming the solar cell array and the inverter so as to adjust the DC voltage output from each solar cell module to the inverter to be equal.

According to the second aspect of the invention, as the voltage adjusting means, the voltage varying means for varying the output voltage of the solar cell module, and the solar cell based on the voltage and current signals input from the solar cell module side. It is provided with means for obtaining an output voltage capable of operating the module at maximum power, and control means for controlling the voltage varying means based on the operating voltage obtained by this means and the preset input voltage of the inverter.

The invention corresponding to claim 3 is a solar cell array configured by connecting a plurality of solar cell modules in parallel, and a DC power output from this solar cell array is converted into AC power to load the load. In the solar cell power generation system having an inverter for supplying to the solar cell module, the solar cell module has voltage adjusting means for adjusting a DC voltage, and a plurality of solar cell modules are connected in series to form a solar cell string. A plurality of battery strings are further connected in parallel to form a solar cell array.

[0021]

In the solar cell power generation system of the invention according to the above-mentioned claims 1 to 2, even when the solar cell array is constructed by using a plurality of types of solar cell modules corresponding to the shape of the roof. , It is possible to obtain the maximum power of all solar cell modules.

Further, in the solar cell power generation system of the invention according to claim 3, in addition to the above-described effects, a plurality of solar cell modules are connected in series to form a solar cell string. By further connecting the solar cells in parallel to each other, it is possible to reduce the current value flowing in the connecting wire that is laid on the roof, as compared with the structure in which the solar cell modules are connected in parallel through the direct current collecting line. .

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In addition, here, in order to simplify the description, a case where the solar cell string and the solar cell module are the same will be described as an example.

FIG. 1 shows an example of the construction of a solar cell power generation system according to the present invention. The same parts as those in FIG. 13 are designated by the same reference numerals. In FIG. 1, a voltage regulator 8 is provided in the output circuit of each solar cell module 1 arranged on the roof. The voltage regulators 8 provided in the output circuits of the respective solar cell modules 1 are connected in parallel with each other via the backflow prevention diodes 4 in series, and the output of this parallel circuit is input to the inverter 7 via the switch 5. . In this case, the backflow prevention diode 4 and the switch 5 are housed in the connection box 6.

FIG. 2 shows a configuration example of a circuit in which the voltage regulator 8 is incorporated in the solar cell module 1. A plurality of solar cells 2 are connected in series, and the voltage regulator 8 is provided at both ends of this series circuit. Connecting. This voltage regulator 8 is housed inside the structure of the solar cell module 1 and is the same as a normal solar cell module in appearance, but its DC output draws out the maximum power of the solar cell module, and other solar cell modules. Has a voltage V in common with.

FIG. 3 is an external view showing a structural example of a solar cell module incorporating the voltage regulator 8. In FIG. 3, a flat voltage regulator 8 is housed in the space existing on the back side of the solar cell module 1.

FIG. 4 is a circuit diagram showing a configuration example of the voltage regulator 8. In FIG. 4, a switching circuit 13 that converts the direct current output of the solar cell module into a high frequency alternating current, and when the output of this switching circuit 13 is input via a transformer 14, converts the high frequency power into a direct current and outputs it to the inverter side. The solar cell module can be operated at maximum power based on the DC voltage and DC current of the solar cell module input from the voltage detector 9 and the current detector 10 provided on the input side of the rectifier 15, the switching circuit 13 The maximum power tracking control circuit 11 for obtaining the output voltage, the output voltage value calculated by the maximum power tracking control circuit 11, and the output voltage of the rectifier 15 detected by the voltage detector 20 are input, and the output voltage and the inverter input in advance. A switching circuit so that the ratio with the voltage VI set as the voltage value becomes the output voltage of the rectifier 15. The control circuit controls the 3 12
It consists of

In the above structure, the transformer 14 also plays a role of galvanically isolating the distribution line system to which the inverter is connected and the solar cell module. A filter for removing a DC ripple component and high frequency noise may be provided on the input side of the switching circuit 13 and the output side of the rectifier 15 as needed.

Next, the operation of the solar cell power generation system configured as described above will be described. Now, when the DC output generated by the solar cell module 1 is input to the voltage regulator 8, the voltage regulator 8 converts the output of the solar cell into a DC voltage V (Pmax) that outputs the maximum power of the solar cell module. In addition, the voltage on the input side of the inverter is controlled to be a predetermined constant voltage value VI. In this case, V (Pmax)
Changes depending on the solar radiation intensity at that time and the temperature of the module, so the voltage regulator 8 obtains the operating voltage for obtaining the maximum power of the solar cell module as the solar cell module voltage, and obtains the ratio of this solar cell module voltage and the inverter input voltage VI. .

The detailed operation of the voltage regulator 8 will now be described with reference to FIG.
Will be described with reference to. When the DC output of the solar cell module is input to the switching circuit 13, the switching circuit 13 converts the DC output into high-frequency AC and inputs the AC output to the rectifier 15 via the transformer 14. This rectifier 15
Then, the high frequency power is converted back to direct current and output to the inverter side.

At this time, in the maximum power tracking control circuit 11,
An output voltage capable of operating the solar cell module at maximum power is obtained based on the detection signals of the DC voltage and the DC current input from the voltage detector 9 and the current detector 10, and the voltage value is given to the control circuit 12. In this control circuit 12,
The switching circuit 13 is configured so that the ratio of the operating voltage for obtaining this maximum power and the voltage VI preset as the inverter input voltage becomes the input voltage detected by the voltage detector 9 and the output voltage detected by the voltage detector 20. To control.

With this operation, the outputs of the voltage regulators 8 connected to the output terminals of the respective solar cell modules are all made equal to the set voltage VI on the input side of the inverter, and are passed through the backflow prevention diode 4 in the junction box 6. Are added to the parallel circuit and further input to the inverter 7 through the switch 5.

Therefore, since the maximum electric power of all the solar cell modules constituting the solar cell array can be obtained, the inverter 7 is operated at an input voltage of a constant value VI,
AC power is output.

Next, another embodiment of the present invention will be described. Figure 5
Shows a circuit configuration example of the voltage regulator 8 incorporated in each solar cell module. In FIG. 5, the DC output of the solar cell module is input to the switching circuit 17 via the reactor 16. This switching circuit 17
Is for converting the DC output of the solar cell module into a high-frequency AC by a switching operation, the output voltage of which is stored in the capacitor 19 via the diode 18 and output as a DC voltage to the inverter side.

On the other hand, the DC voltage and the DC current of the solar cell module respectively detected by the voltage detector 9 and the current detector 10 provided on the input side of the switching circuit 13 are input to the maximum power tracking circuit 11. The maximum power follow-up circuit 11 obtains an output voltage capable of operating the solar cell module with the maximum power as in the above-described embodiment, and supplies the output voltage to the control circuit 12. Further, the inter-terminal voltage of the capacitor 19 detected by the voltage detector 20 is input to the control circuit 12, and the switching circuit 13 is controlled by the same operation as that of the above-described embodiment.

Therefore, even if the voltage detector 8 having such a structure is used, the same operational effect as that of the above-described embodiment can be obtained. Further, in this embodiment, since the transformer and the rectifier shown in FIG. 4 are not used, the circuit does not have an insulating function, but the components of the circuit are simplified and the cost can be reduced.

FIG. 6 shows another structural example of a solar cell module in which a voltage regulator is incorporated. In FIG. 6, the voltage regulator 8 is fixed to the back surface of the solar cell module 1, and its DC output terminal is a terminal for connecting to a DC current collecting line installed on the roof and a groove shape for passing the DC current collecting line. It has a hollow portion. FIG. 7 shows an example of a state in which the solar cell modules thus configured are connected in parallel to each other via a direct current collecting line.

In the configuration of each of the embodiments described above, all the solar cell modules having the voltage regulator are connected in parallel. For example, if the output voltage of the solar battery cell group connected in series in the solar battery module is about 40 V and the output of the voltage regulator is 200 V, AC1 can be easily used by the inverter.
It can be converted to electric power of 00V.

The present invention is not limited to the connection configuration of the above solar cell module, and the solar cell power generation system may be configured as the connection as shown in FIG. That is, a plurality of solar cell modules having voltage adjusting means for adjusting a DC voltage and outputting a predetermined constant voltage are connected in series to form a solar cell string, and a plurality of the solar cell strings are further connected in parallel. The solar cell array is configured as described above, and its output is input to the inverter 7.

With this connection structure, the value of the current flowing through the connection line on the roof can be reduced as compared with the structure in which the solar cell modules as shown in FIG. 7 are connected in parallel via the direct current collecting line. be able to.

It is to be noted that a string is formed by connecting a plurality of solar cell modules in series and a voltage regulator is provided for each string, or a voltage regulator is provided only for strings of different voltages. It goes without saying that the present invention also includes the case of collectively performing the above.

[0042]

As described above, according to the present invention, even when a solar cell array is constructed using solar cell modules having a plurality of types of shapes corresponding to the shape of the roof, all solar cell modules are formed. It is possible to provide a solar cell power generation system that can utilize the maximum power of

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a solar cell power generation system according to the present invention.

FIG. 2 is a circuit configuration diagram inside the solar cell module according to the embodiment.

FIG. 3 is an external view showing the back surface side of the solar cell module in the example.

FIG. 4 is a circuit configuration diagram of a voltage regulator in the embodiment.

FIG. 5 is a circuit configuration diagram of a voltage regulator according to a second embodiment of the present invention.

FIG. 6 is an external view showing a back surface side of a solar cell module according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram of a solar cell power generation system using the solar cell module according to the embodiment.

FIG. 8 is a circuit configuration diagram showing a fourth embodiment of the present invention.

FIG. 9 is an explanatory diagram showing an example of a solar cell module installed on the roof of a house.

FIG. 10 is an explanatory view showing another example of a solar cell module installed on the roof of a house.

FIG. 11 is an external view of a solar cell module used in the system.

FIG. 12 is a circuit configuration diagram of a solar cell module used in the system.

FIG. 13 is a circuit diagram showing a configuration example of a conventional solar cell power generation system.

[Explanation of symbols]

1 ... Solar cell module, 2 ... Solar cell, 3 ...
… Housing, 4 …… Backflow prevention diode, 5 …… Switch,
6 ... Junction box, 7 ... Inverter, 8 ... Voltage regulator,
9 ... Voltage detector, 10 ... Current detector, 11 ... Maximum power tracking control circuit, 12 ... Control circuit, 13, 17 ...
Switching circuit, 14 ... Transformer, 15 ... Rectifier, 16 ... Reactor, 18 ... Diode, 19 ...
… Capacitor.

Claims (3)

[Claims] 1. A solar cell array comprising a plurality of solar cell modules connected in parallel, and an inverter for converting DC power output from the solar cell array into AC power and supplying the AC power to a load. In the solar cell power generation system, voltage adjusting means is provided between each of the solar cell modules forming the solar cell array and the inverter so that the DC voltage output from each of the solar cell modules to the inverter becomes equal. A solar cell power generation system. 2. The voltage adjusting means can operate the solar cell module at maximum power based on the voltage varying means for varying the output voltage of the solar cell module and the voltage and current signals input from the solar cell module side. 2. The apparatus according to claim 1, further comprising: a means for obtaining an output voltage, and a control means for controlling the voltage varying means based on an operating voltage obtained by the means and a preset input voltage of the inverter. The solar cell power generation system described. 3. A solar cell array comprising a plurality of solar cell modules connected in parallel, and an inverter for converting DC power output from the solar cell array into AC power and supplying the AC power to a load. In the solar cell power generation system, the solar cell module has a voltage adjusting means for adjusting a DC voltage, a plurality of the solar cell modules are connected in series to form a solar cell string, and the solar cell strings are further arranged in parallel. A solar cell power generation system characterized in that a solar cell array is configured by connecting them.