KR20130087171A - Photovoltaic module, and photovoltaic system - Google Patents

Abstract

PURPOSE: A sunlight module including a junction box and a sunlight system thereof are provided to improve output current quality by including a first switching element and a second switching element. CONSTITUTION: A sunlight module includes a plurality of solar cells. A junction box (200) includes a DC/DC converter (530). The DC/DC converter converts a level of DC power to output the power. A first switching element (S1) supplies the DC power by switching the power. A fly back converter includes a second switching element (S2). [Reference numerals] (550) Control unit

Description

[0001] DESCRIPTION [0002] Photovoltaic modules, and photovoltaic systems [

The present invention relates to a photovoltaic module and a photovoltaic system, and more particularly, to a photovoltaic module and a photovoltaic system capable of improving output current quality.

With the recent depletion of existing energy sources such as oil and coal, interest in alternative energy to replace them is increasing. Among them, solar cells are attracting attention as a next-generation battery that converts solar energy directly into electrical energy using semiconductor devices.

On the other hand, the photovoltaic module means that solar cells for solar power generation are connected in series or parallel, and the photovoltaic module can include a junction box for collecting the electricity produced by the solar cell.

It is an object of the present invention to provide a solar module and a solar light system that can improve output current quality.

According to an aspect of the present invention, there is provided a solar module including: a solar cell module including a plurality of solar cells; and a dc / dc converter for level-converting and outputting a DC power supplied from the solar cell module The dc / dc converter includes a first switching element for switching and supplying a DC power supplied from the solar cell module, and a second switching element. The dc / dc converter includes a DC power source, And a flyback converter for outputting power.

According to another aspect of the present invention, there is provided a solar photovoltaic system comprising: a plurality of solar cell modules; and a power source for converting the level of DC power supplied from each solar cell module and a plurality of junction boxes including a dc / dc converter, wherein each of the dc / dc converters includes a first switching element for switching and supplying a DC power supplied from the solar cell module, and a second switching element, And a flyback converter that outputs the level-converted DC power using a power source.

According to an embodiment of the present invention, the dc / dc converter includes a first switching element for switching and supplying a DC power supplied from the solar cell module, and a second switching element, By including the flyback converter that outputs DC power, the output current quality can be improved.

Particularly, the dc / dc converter is operated in the first operation mode of the flyback converter and the second operation mode of the flyback converter due to the turning off of the second switching element by on / off repetition of the second switching element So that the output current quality can be improved.

1 is a front view of a solar module according to an embodiment of the present invention.
Fig. 2 is a rear view of the solar module of Fig. 1;
3 is an exploded perspective view of the solar cell module of FIG.
4 is an example of a bypass diode configuration of the solar module of FIG.
Fig. 5 illustrates a voltage versus current curve of the solar module of Fig.
6 illustrates a voltage versus power curve of the solar module of FIG.
7 is an example of an internal circuit diagram of a junction box of the solar module shown in Fig.
8A and 8B illustrate an embodiment and a comparative example of the output current outputted from the dc / dc converter of FIG.
9A to 9B are diagrams referred to in the description of the operation of the circuit diagram of Fig.
10 is another example of the internal circuit diagram of the junction box of the solar module shown in Fig.
11 is an example of a configuration diagram of a solar photovoltaic system according to an embodiment of the present invention.
12 is another example of the configuration of a solar photovoltaic system according to an embodiment of the present invention.
13A to 13B are views referred to explain power optimizing of a solar photovoltaic system according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.

The suffix "module" and " part "for components used in the following description are given merely for convenience of description, and do not give special significance or role in themselves. Accordingly, the terms "module" and "part" may be used interchangeably.

FIG. 1 is a front view of a solar module according to an embodiment of the present invention, FIG. 2 is a rear view of the solar module of FIG. 1, and FIG. 3 is an exploded perspective view of the solar module of FIG.

1 to 3, a solar module 50 according to an embodiment of the present invention includes a solar cell module 100 and a junction box 200 located on one side of the solar cell module 100 . The solar module 50 may further include a heat dissipating member (not shown) disposed between the solar cell module 100 and the junction box 200.

First, the solar cell module 100 may include a plurality of solar cells 130. The first sealing material 120 and the second sealing material 150 located on the lower surface and the upper surface of the plurality of solar cells 130 and the rear substrate 110 and the second sealing material 120 located on the lower surfaces of the first sealing material 120, And may further include a front substrate 160 positioned on the top surface of the sealing member 150.

First, the solar cell 130 is a semiconductor device that converts solar energy into electrical energy. The solar cell 130 includes a silicon solar cell, a compound semiconductor solar cell, A tandem solar cell, a dye-sensitized solar cell, or a CdTe or CIGS type solar cell.

The solar cell 130 is formed of a light receiving surface on which solar light is incident and a rear surface opposite to the light receiving surface. For example, the solar cell 130 includes a silicon substrate of a first conductivity type, a second conductivity type semiconductor layer formed on the silicon substrate and having a conductivity type opposite to that of the first conductivity type, An antireflection film formed on the second conductive type semiconductor layer and having at least one opening exposing a part of the surface of the second conductive type semiconductor layer; And a rear electrode formed on the rear surface of the silicon substrate.

Each solar cell 130 may be electrically connected in series, parallel, or series-parallel. Specifically, a plurality of solar cells 130 can be electrically connected by a ribbon 133. [ The ribbon 133 may be bonded to the front electrode formed on the light receiving surface of the solar cell 130 and the rear electrode collecting electrode formed on the rear surface of another adjacent solar cell 130. [

In the figure, it is illustrated that the ribbon 133 is formed in two lines, and the solar cell 130 is connected in series by the ribbon 133 to form the solar cell string 140. By this, six strings 140a, 140b, 140c, 140d, 140e and 140f are formed, and each string includes ten solar cells. Unlike the drawings, various modifications are possible.

On the other hand, each solar cell string can be electrically connected by a bus ribbon. 1 shows a first solar cell string 140a and a second solar cell string 140b respectively formed by bus ribbons 145a, 145c and 145e disposed under the solar cell module 100, The battery string 140c and the fourth solar cell string 140d illustrate that the fifth solar cell string 140e and the sixth solar cell string 140f are electrically connected. 1 shows the second solar cell string 140b and the third solar cell string 140c respectively by the bus ribbons 145b and 145d disposed on the top of the solar cell module 100, And that the battery string 140d and the fifth solar cell string 140e are electrically connected.

On the other hand, the ribbon connected to the first string, the bus ribbons 145b and 145d, and the ribbon connected to the fourth string are electrically connected to the first through fourth conductive lines 135a, 135b, 135c, and 135d, respectively The first to fourth conductive lines 135a to 135d are connected to the bypass diodes Da, Db, and Dc in the junction box 200 disposed on the back surface of the solar cell module 100. In the drawing, the first through fourth conductive lines 135a, 135b, 135c, and 135d extend through the openings formed on the solar cell module 100 to the back surface of the solar cell module 100. FIG.

It is preferable that the junction box 200 is disposed closer to an end of the solar cell module 100 where the conductive lines extend.

1 and 2, since the first to fourth conductive lines 135a, 135b, 135c, and 135d extend from the top of the solar cell module 100 to the back surface of the solar cell module 100, ) Is located at the upper part of the back surface of the solar cell module 100. FIG. Thereby, the length of the conductive line can be reduced, and the power loss can be reduced.

1 and 2, when the first to fourth conductive lines 135a, 135b, 135c, and 135d extend from the bottom of the solar cell module 100 to the back surface of the solar cell module 100, The solar cell module 200 may be positioned at the lower part of the back surface of the solar cell module 100.

The back substrate 110 may be, but is not limited to, a TPT (Tedlar / PET / Tedlar) type having a waterproof, insulating and ultraviolet shielding function as a back sheet. 3, the rear substrate 110 may be formed in various shapes such as a circular shape or a semicircular shape depending on the environment in which the solar cell module 100 is installed.

The first sealing member 120 may be attached to the rear substrate 110 to have the same size as the rear substrate 110 and a plurality of solar cells 130 may be formed on the first sealing member 120 And can be positioned adjacent to each other so as to achieve the same.

The second sealing member 150 may be positioned on the solar cell 130 and may be laminated to the first sealing member 120.

Here, the first sealant 120 and the second sealant 150 allow each element of the solar cell to chemically bond. The first sealing material 120 and the second sealing material 150 can be various examples such as an ethylene vinyl acetate (EVA) film.

On the other hand, the front substrate 160 is preferably placed on the second sealing material 150 so as to transmit sunlight, and is preferably made of tempered glass in order to protect the solar cell 130 from an external impact or the like. Further, it is more preferable to use a low-iron-content tempered glass containing a small amount of iron in order to prevent the reflection of sunlight and increase the transmittance of sunlight.

The junction box 200 is mounted on the back surface of the solar cell module 100 and can be power-converted using the DC power supplied from the solar cell module 100. Specifically, a capacitor unit (520 in FIG. 7) for storing DC power can be provided. Further, the junction box 200 may further include a dc / dc converter (530 in Fig. 7) for level-converting and outputting the DC power. In addition, the junction box 200 may further include bypass diodes (Da, Db, Dc) that prevent the current between the solar cell strings from flowing backward. Further, it may further include an inverter (540 in Fig. 7) for converting the direct current power into the alternating current power. This will be described later with reference to FIG.

As described above, the junction box 200 according to the embodiment of the present invention includes at least bypass diodes Da, Db, and Dc, a capacitor unit 520 (FIG. 7) (530 of FIG. 7).

When the junction box 200 is formed integrally with the solar cell module 100, the loss of the DC power generated in each solar cell module 100 is minimized, as in the solar cell system shown in FIG. 11 or FIG. So that it can be efficiently managed. On the other hand, the junction box 200 integrally formed can be called a MIC (Module Integrated Converter) circuit.

On the other hand, in order to prevent moisture penetration of the circuit elements in the junction box 200, a coating for preventing moisture permeation may be performed using silicon or the like inside the junction box.

An opening (not shown) is formed in the junction box 200 so that the first to fourth conductive lines 135a, 135b, 135c and 135d are connected to the bypass diodes Da, Db and Dc in the junction box Can be connected.

On the other hand, during operation of the junction box 200, high heat is generated from the bypass diodes Da, Db, and Dc, and the generated heat is transmitted to the specific solar cell 130 Can be reduced.

In order to prevent this, the solar module 50 according to the embodiment of the present invention may further include a heat dissipating member (not shown) disposed between the solar cell module 100 and the junction box 200. In order to disperse the heat generated in the junction box 200, the cross sectional area of the heat dissipating member (not shown) is preferably larger than the cross sectional area of the plate (not shown). For example, on the entire rear surface of the solar cell module 100. The heat dissipating member (not shown) is preferably formed of a metal material such as gold (Au), silver (Ag), copper (Cu), aluminum (Al), tungsten (W) or the like with good thermal conductivity.

On the other hand, an external connection terminal (not shown) for outputting a power-converted DC power or an AC power to the outside may be formed on one side of the junction box 160.

4 is an example of a bypass diode configuration of the solar module of FIG.

Referring to the drawings, bypass diodes Da, Db, and Dc may be connected corresponding to six solar cell strings 140a, 140b, 140c, 140d, 140e, and 140f. Specifically, the first bypass diode Da is connected between the first solar cell string and the first bus ribbon 145a, and is connected to the first solar cell string 140a or the second solar cell string 140b When the reverse voltage is generated, the first solar cell string 140a and the second solar cell string 140b are bypassed.

For example, when a voltage of approximately 0.6 V generated in a normal solar cell is generated, the potential of the cathode electrode is approximately 12 V (= 0.6 V * 20), as compared with the potential of the anode electrode of the first bypass diode Da Lt; / RTI > That is, the first bypass diode Da operates normally, not bypass.

On the other hand, when a hot spot occurs due to shading or foreign matter adhering to any solar cell of the first solar cell string 140a, the voltage generated in any one solar cell is approximately 0.6V (About -15 V), rather than a voltage of about < / RTI > Accordingly, the potential of the anode electrode of the first bypass diode Da becomes higher by about 15 V than that of the cathode electrode. Accordingly, the first bypass diode Da performs the bypass operation. Therefore, the voltage generated in the solar cell in the first solar cell string 140a and the second solar cell string 140b is not supplied to the junction box 200. [ In this way, when a reverse voltage generated in some solar cells is generated, it is possible to prevent destruction of the solar cell or the like by bypassing. In addition, except for the hotspot area, it is possible to supply the generated DC power.

Next, the second bypass diode Db is connected between the first bus ribbon 145a and the second bus ribbon 145b, and is connected to the third solar cell string 140c or the fourth solar cell string 140d When the reverse voltage is generated, the third solar cell string 140c and the fourth solar cell string 140d are bypassed.

Next, the third bypass diode Dc is connected between the first solar cell string and the first bus ribbon 145a, and is connected to the first solar cell string 140a or the second solar cell string 140b When the voltage is generated, the first solar cell string and the second solar cell string are bypassed.

4, unlike FIG. 4, six bypass diodes can be connected corresponding to six solar cell strings, and various other modifications are possible.

FIG. 5 illustrates a voltage vs. current curve of the solar module of FIG. 1, and FIG. 6 illustrates a voltage versus power curve of the solar module of FIG.

Referring to FIG. 5, as the open-circuit voltage Voc supplied from the solar cell module 100 increases, the short current supplied from the solar cell module 100 becomes smaller. According to the voltage-current curve L, the voltage Voc is stored in the capacitor unit 520 provided in the junction box 200.

Referring to FIG. 6, the maximum power Pmpp supplied from the solar cell module 100 may be calculated by a maximum power point tracking algorithm (MPPT). For example, while the open-circuit voltage Voc is decreased from the maximum voltage V1, power is calculated for each voltage, and it is determined whether the calculated power is the maximum power. Since the power increases from the voltage V1 to the voltage Vmpp, the calculated power is updated and stored. Then, the power decreases from the voltage Vmpp to the voltage V2, so that Pmpp corresponding to the voltage Vmpp is determined as the maximum power.

As described above, when hot spots do not occur, only one inflection point occurs in the voltage power curve L. Therefore, the maximum power can be easily calculated only by exploring the V2 section in the V1 section.

FIG. 7 is an example of an internal circuit diagram of a junction box of the solar module of FIG. 1, FIGS. 8A to 8B illustrate an example of a output current outputted from the dc / dc converter of FIG. 7 and a comparative example, FIG. 9B is a diagram referred to in the description of the operation of the circuit diagram of FIG.

Referring to FIG. 7, a junction box 200 according to an embodiment of the present invention includes a bypass diode unit 510, a capacitor unit 520, a dc / dc converter 530, an inverter 540, 550).

The junction box 200 outputs AC power. Since the junction box 200 is capable of AC power output, it can be called a junction box having a micro inverter.

The bypass diode section 510 is connected to the first to fourth conductive lines 135a, 135b, 135c and 135d arranged between the respective angles of the a-node, b-node, c- And third bypass diodes Da, Db, and Dc.

The capacitor unit 520 stores the DC power supplied from the solar cell module 100. Although three capacitors Ca, Cb and Cc are connected in parallel in the figure, they may be connected in series or in series-parallel combination.

 The dc / dc converter 530 performs level conversion using the DC power stored in the capacitor unit 520. In the figure, there are shown a first switching device S1 for switching and supplying a DC power supplied from a solar cell module, a flyback converter for converting the level by using a DC power supplied through a first switching device S1, (flyback converter).

The flyback converter includes a transformer T for amplifying and outputting a current according to a winding ratio, a second switching device S2 connected between the input side of the transformer T and the ground terminal for performing a switching operation, A diode D2 for conducting current in one direction, and a capacitor C1 for storing the amplified current or voltage.

The dc / dc converter 530 according to the embodiment of the present invention includes the first switching device S1 and the flyback converter to improve the output current quality by configuring the dc / dc converter as a non-insulation type . In particular, by allowing the flyback converter to operate in a buck converter mode, the output current quality is improved.

This will be described later with reference to Figs. 8A to 9B.

Meanwhile, the switching operation of the first switching device S1 and the second switching device in the dc / dc converter 530 is controlled by the control unit 550. [

Next, the inverter 540 converts the level-converted DC power from the dc / dc converter 530 into AC power. In the drawing, a full-bridge inverter is illustrated. Namely, the upper and lower arm switching elements Sa and Sb connected in series to each other and the lower arm switching elements S'a and S'b are paired, and two pairs of upper and lower arm switching elements are connected in parallel to each other (Sa & Sb & S'b). Diodes are connected in anti-parallel to each switching element Sa, S'a, Sb, S'b.

The switching elements in the inverter 540 are turned on / off based on the inverter switching control signal from the inverter control unit (not shown). As a result, AC power having a predetermined frequency is output. Preferably, it has a frequency (approximately 60 Hz) equal to the alternating frequency of the grid.

Meanwhile, a capacitor unit (not shown) may be further provided between the dc / dc converter 530 and the inverter 540 to store the level-converted dc power. The capacitor unit (not shown) may include a plurality of capacitors, similar to the capacitor unit 520 described above.

As shown in Fig. 7, a capacitor section for storing DC power in the junction box, a dc / dc converter for level-converting and outputting the stored DC power, and an inverter for converting the level- It is possible to easily supply AC power through the junction box. In addition, it is easy to install the solar module, and it is advantageous to expand the capacity of the solar system including a plurality of solar modules and the system configuration.

The input current sensing unit A senses an input current ic1 input to the dc / dc converter 530. The input voltage sensing unit B receives the input current ic1 input to the dc / dc converter 530, And senses the voltage vc1. The sensed input current ic1 and the input voltage vc1 are input to the control unit 550. [

The output current sensing unit C senses the output current ic2 output from the dc / dc converter 530 and the output voltage sensing unit B outputs the output And senses the voltage vc2. The sensed output current ic2 and the output voltage vc2 are input to the control unit 550. [

On the other hand, the control unit 550 may output a control signal for controlling the first switching device S1 and the second switching device S2 of the dc / dc converter 530 of FIG.

On the other hand, the control unit 550 may output an inverter control signal for controlling the switching element of the inverter 540.

The control unit 550 controls the first switching unit 530 in the dc / dc converter 530 based on at least one of the sensed input current ic1, the input voltage vc1, the output current ic2 or the output voltage vc2. The turn-on timing signal of the element S1 and the second switching element S2 can be outputted.

On the other hand, the control unit 550 can control the dc / dc converter 530 to calculate the maximum power point for the solar cell module 100 and accordingly output the DC power corresponding to the maximum power .

FIGS. 8A and 8B illustrate an embodiment and a comparative example of the output current outputted from the dc / dc converter of FIG. 7, and FIGS. 9A and 9B are views referred to in the description of the operation of the circuit diagram of FIG.

Referring to the drawings, the dc / dc converter 530 according to the embodiment of the present invention operates in two operation modes.

Specifically, the first operation mode (mode 1) and the second operation mode (mode 2) due to the turn-off of the second switching element S2 due to on / off repetition of the second switching element S2, As shown in FIG.

9A, when the first switching device S1 and the second switching device S2 are turned on, the DC power supplied from the solar cell module 100, specifically, the current flows through the first switching device S1 ), The input side of the transformer T, and the second switching element S2.

9B, when the first switching device S1 is turned on and the second switching device S2 is turned off, the DC power supplied from the solar cell module 100, specifically, the current Becomes unable to flow to the ground terminal.

9A and 9B are repeated, that is, when the second switching element S2 is turned on / off repeatedly while the first switching element S1 is turned on, The output side outputs the converted current according to the turns ratio of the transformer T. This mode may be referred to as a first mode of operation (mode 1) of the dc / dc converter 530. Accordingly, the voltage across the capacitor C1 may be equal to the voltage waveform in the first operation mode (mode 1) of Fig. 8A.

On the other hand, when the second switching element S2 is turned off as shown in Fig. 9C, the flyback converter can operate as a buck converter. Specifically, when the second switching device S2 is turned off, the energy stored on the output side of the transformer T is supplied to the internal diode (parasitic diode) of the second switching device S2 and the output side of the transformer T As a current component. At this time, the first switching device S1 may also be turned off.

The second switching element S2 is turned off for a predetermined time and the first switching element S1 is also turned off so that the internal diode (parasitic diode) of the second switching element S2, The current component flowing through the output side converges to zero. Accordingly, the voltage across the capacitor C1 may be the same as the voltage waveform in the second operation mode (mode 2) of Fig. 8A.

On the other hand, when there is no second operation mode, that is, in the first operation mode, the voltage across the capacitor C1 is biased by a constant voltage as shown in FIG. 8B do. Particularly, when there is no first switching element S1 and DC power is continuously supplied from the solar cell module 100, only the turn-off of the second switching element S2 during turn-on / So that the voltage of the transistor can not drop to 0V. As a result, the output current quality deteriorates, and in particular, the influence of the harmonic current component becomes large.

8A, when the dc / dc converter 530 is divided into a first operation mode (mode 1) and a second operation mode (mode 2) according to the embodiment of the present invention, The voltage at both ends is not biased but falls to 0V. Therefore, the current quality of the output current outputted from the dc / dc converter 530 can be improved. In particular, the harmonic current component is significantly reduced.

10 is another example of the internal circuit diagram of the junction box of the solar module shown in Fig.

10, a junction box 200 according to an embodiment of the present invention includes a bypass diode unit 510, a capacitor unit 520, a dc / dc converter 530, and a control unit 550 . Unlike the internal circuit diagram of FIG. 7, the internal circuit diagram of FIG. 10 is characterized in that it does not include the inverter 540.

Accordingly, the junction box 200 can output DC power. In this case, when the junction box 200 performs a power optimizing function, the junction box 200 may be referred to as a power optimizer.

As shown in FIG. 10, the DC power source can be easily supplied through the junction box by including the capacitor unit for storing the DC power source in the junction box and the dc / dc converter for converting and outputting the stored DC power source. In addition, it is easy to install the solar module, and it is advantageous to expand the capacity of the solar system including a plurality of solar modules and the system configuration.

7 and FIG. 10, the junction box 200 may include only the bypass diode 510 and the capacitor 520. Accordingly, the dc / dc converter 530 and the inverter 540 may be separately disposed outside the junction box 200. [

11 is an example of a configuration diagram of a solar photovoltaic system according to an embodiment of the present invention.

Referring to the drawings, the solar photovoltaic system of Fig. 11 includes a plurality of solar modules 50a, 50b, ..., 50n. Each solar module 50a, 50b, ..., 50n may include junction boxes 200a, 200b, ..., 200n for outputting AC power. The junction boxes 200a, 200b, ..., 200n may be referred to as junction boxes having microinverters. The alternating current power output from the junction boxes 200a, 200b, ..., as shown in FIG.

Meanwhile, the internal circuit of the junction box 200 of FIG. 7 according to the embodiment of the present invention can be applied to the microinverter of FIG.

7, each of the junction boxes 200a, 200b, ..., 200n includes a bypass diode unit 510, a capacitor unit 520, a dc / dc converter 530, an inverter 540, And may include a control unit 550. 7, the dc / dc converter 530 includes a first switching device S1 for switching the DC power supplied from the solar cell module to supply the DC power, a DC power supply (not shown) supplied through the first switching device S1, And a flyback converter for level-converting and outputting the output signal. The operation is the same as that of Figs. 8A to 9B.

12 is another example of the configuration of a solar photovoltaic system according to an embodiment of the present invention.

Referring to the drawings, the solar photovoltaic system of Fig. 12 includes a plurality of solar modules 50a, 50b, ..., 50n. Each solar module 50a, 50b, ..., 50n may include junction boxes 1200a, 1200b, ..., 1200n for outputting DC power. In addition, a separate inverter 1210 for converting the DC power output from each of the solar module modules 50a, 50b, ..., 50n into AC power is further provided. At this time, the junction boxes 1200a, 1200b, ..., 1200n may be junction boxes having power optimizers for efficiently outputting DC power.

Meanwhile, the internal circuit of the junction box 200 of FIG. 10 according to the embodiment of the present invention can be applied to the power optimizer of FIG.

10, each of the junction boxes 200a, 200b, ..., 200n includes a bypass diode unit 510, a capacitor unit 520, a dc / dc converter 530, and a control unit 550, . ≪ / RTI > 10, the dc / dc converter 530 includes a first switching device S1 for switching and supplying the DC power supplied from the solar cell module, a DC power supply And a flyback converter for level-converting and outputting the output signal. The operation is the same as that of Figs. 8A to 9B.

13A to 13B are diagrams for explaining power optimization of a solar photovoltaic system according to an embodiment of the present invention.

First, referring to FIG. 13A, a case where power optimizing is not applied will be described. In the case where a plurality of solar cell modules are connected in series as shown in the drawing, when hot spots are generated in some solar cell modules 1320 and some power loss occurs (for example, 70W power supply) A normal solar cell module 1310 also causes some power loss (for example, 70W power supply). Therefore, only 980W of power is supplied in total.

Next, referring to Fig. 13B, a case where power optimization is applied will be described. When a hot spot occurs in some solar cell modules 1320 and some power loss occurs (for example, 70W power supply), the current supplied from the corresponding solar cell module 1320 is supplied to another solar cell module 1310, The voltage output from the solar cell module 1320 is lowered so as to be equal to the current supplied from the solar cell module 1320. [ Accordingly, in the solar cell module 1320 in which the hot spot has occurred, some power loss occurs (for example, 70W power supply), but in the normal solar cell module 1310, Power supply). Therefore, a total power of 1340 W can be supplied.

As described above, according to the power optimizing, the voltage supplied from the solar cell module in which the hot spot occurs can be adjusted in accordance with the current supplied from another solar cell module. To this end, each solar cell module receives a current value or a voltage value supplied from another solar cell module, and can control a voltage output in the solar cell module.

On the other hand, according to the embodiment of the present invention, the junction box 200 of FIG. 10 can be applied to the power optimizer of FIG. 13B.

It is to be understood that the invention is not to be limited in its application to the details of construction and the manner in which the above described embodiments of the invention are put into practice, .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention.

Claims (14)

A solar cell module comprising a plurality of solar cells; And
And a junction box including a dc / dc converter for level-converting and outputting DC power supplied from the solar cell module,
The dc / dc converter includes:
A first switching device for switching and supplying a DC power supplied from the solar cell module; And
And a flyback converter having a second switching element and outputting a level-converted DC power using the DC power. The method according to claim 1,
The dc / dc converter includes:
A first operation mode of the flyback converter by on / off repetition of the second switching element,
And the second operation mode of the flyback converter due to the turning-off of the second switching element. 3. The method of claim 2,
The dc / dc converter includes:
And in the second mode of operation, operates in a buck converter mode. 3. The method of claim 2,
The dc / dc converter includes:
And in the second operation mode, when the second switching element is turned off, the first switching element is also turned off. The method according to claim 1,
Further comprising a controller for controlling the dc / dc converter based on at least one of an input power input to the dc / dc converter and an output power output from the dc / dc converter. 6. The method of claim 5,
The junction box includes:
And a control unit for controlling the solar cell module. The method according to claim 1,
The junction box includes:
And a bypass diode for bypassing a solar cell generating a reverse voltage among the plurality of solar cells. The method according to claim 1,
The junction box includes:
And an inverter for converting the level-converted DC power from the dc / dc converter into AC power and outputting the AC power. The method according to claim 1,
The junction box includes:
Wherein the solar cell module is integrated with the solar cell module. A plurality of solar cell modules;
And a plurality of junction boxes including a dc / dc converter for level-converting and outputting a DC power supplied from each of the solar cell modules corresponding to each of the solar cell modules,
Each of the dc / dc converters includes:
A first switching device for switching and supplying a DC power supplied from the solar cell module; And
And a flyback converter having a second switching element and outputting a level-converted DC power using the DC power. 11. The method of claim 10,
The dc / dc converter includes:
A first operation mode of the flyback converter by on / off repetition of the second switching element,
And the second operation mode of the flyback converter due to the turning-off of the second switching element. 12. The method of claim 11,
The dc / dc converter includes:
And in the second operation mode, when the second switching element is turned off, the first switching element is also turned off. 11. The method of claim 10,
The junction box includes:
And an inverter for converting the level-converted DC power from the dc / dc converter into an AC power and outputting the AC power. 11. The method of claim 10,
And an inverter for receiving DC power from each of the plurality of junction boxes, converting the DC power into an AC power, and outputting the AC power to the system.

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