KR102233898B1 - Transformer and power converting apparatus icnluing the same - Google Patents

Abstract

The present invention relates to a transformer and a power conversion device having the same. A power conversion device according to an embodiment of the present invention converts DC power from a solar cell module and includes a converter unit including a plurality of interleaving converters, and a control unit for controlling the converter unit, and the control unit includes a plurality of interleaving converters. The switching period of is varied, and the phase difference for the operation period between the plurality of interleaving converters is varied in response to the change of the switching period. This enables high-efficiency power conversion during power conversion.

Description

Transformer and power converting apparatus having the same

The present invention relates to a transformer and a power conversion device having the same, and more particularly, to a transformer capable of converting high-efficiency power during power conversion, and a power conversion device having the same.

Recently, as existing energy resources such as oil and coal are expected to be depleted, interest in alternative energy to replace them is increasing. Among them, solar cells are in the spotlight as a next-generation battery that directly converts solar energy into electrical energy using semiconductor devices.

Meanwhile, the solar module refers to a state in which solar cells for solar power generation are connected in series or in parallel, and the solar module may include a junction box that collects electricity produced by the solar cells.

An object of the present invention is to provide a transformer capable of converting high-efficiency power during power conversion, and a power conversion device having the same.

A transformer according to an embodiment of the present invention for achieving the above object is a bobbin formed with a hollow and including a winding guide portion for guiding a winding wound on a side thereof, a first protrusion inserted into the hollow, and surrounding the bobbin. A first core having first and second side portions spaced apart, a second protrusion inserted into the hollow, and third and fourth side portions that surround the bobbin and are spaced apart from each other, and are coupled to the bobbin together with the first core. A second core and a winding wound around a winding guide in the bobbin are provided.

On the other hand, the power conversion device according to an embodiment of the present invention for achieving the above object, a converter unit for converting DC power from a solar cell module, a control unit for controlling the converter unit, and a capacitor for storing a voltage output from the converter unit. Including, the converter unit includes a switching element, a transformer that performs power conversion by a switching operation of the switching element, and a diode element disposed at the output terminal of the transformer, the transformer is formed with a hollow, a winding winding on the side A bobbin including a winding guide portion for guiding the bobbin, a first protrusion inserted into the hollow, and a first core having first and second side portions spaced apart from each other surrounding the bobbin, a second protrusion inserted into the hollow, and a bobbin. A second core having third and fourth side portions that are surrounded and spaced apart from each other, and a second core coupled to the bobbin together with the first core, and a winding wound around a winding guide portion in the bobbin.

According to an embodiment of the present invention, the transformer includes a bobbin having a hollow formed therein and including a winding guide portion for guiding a winding wound on a side thereof, a first protrusion inserted into the hollow, and a first and spaced apart from each other surrounding the bobbin. A second core having a first core having a second side portion, a second protrusion inserted into the hollow, and third and fourth side portions surrounding the bobbin and spaced apart from each other, and coupled to the bobbin together with the first core, and By providing a winding wound around the winding guide portion in the bobbin, high-efficiency power conversion during power conversion is possible.

1 is an example of a configuration diagram of a solar system according to an embodiment of the present invention.
2 is a front view of a solar module according to an embodiment of the present invention.
3 is a rear view of the solar module of FIG. 2.
4 is an exploded perspective view of the solar cell module of FIG. 2.
5 is an example of a configuration of a bypass diode of the solar module of FIG. 2.
6 is an example of a block diagram of a power conversion module inside the junction box of FIG. 2.
7A is an example of an internal circuit diagram of the power conversion module of FIG. 6.
7A is an example of an internal circuit diagram of the power conversion module of FIG. 6.
7B is another example of an internal circuit diagram of the power conversion module of FIG. 6.
8A and 8B are diagrams illustrating a method of operating the power conversion module of FIG. 6.
9A to 9B are views referenced for explaining the operation of the tapped inductor boost converter of FIG. 7A.
10A and 10B are diagrams referenced for explaining that the converter unit of FIG. 6 outputs a pseudo DC power using an input power source.
11 is a diagram illustrating an example of a converter unit.
12 is a perspective view of a bobbin in a transformer according to an embodiment of the present invention.
13 to 17 are views referenced in the description of FIG. 12.

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

The suffixes "module" and "unit" for the constituent elements used in the following description are given in consideration of only the ease of preparation of the present specification, and do not impart a particularly important meaning or role. Therefore, the "module" and "unit" may be used interchangeably with each other.

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

Referring to the drawings, the solar system 10 of FIG. 1 may include a plurality of solar modules 50a, 50b, ..., 50n.

Each solar module (50a, 50b, ..., 50n) is provided with a plurality of solar cells, each solar cell module (100a, 1000b, ..., 100n) for generating a DC power supply, and each solar cell A junction box 200a that is attached to the back of the modules 100a, 1000b, ..., 100n and converts and outputs DC power from each solar cell module 100a, 1000b, ..., 100n into AC power. , 200b, ..., 200n).

At this time, the junction box (200a, 200b, ..., 200n) is a power conversion module (Fig. 6) that converts DC power from each solar cell module (100a, 1000b, ..., 100n) into AC power and outputs it. Of 700) may be provided.

The power conversion module (700 in FIG. 6) may include a bypass diode (Da, Db, Dc), a converter unit (530 in FIG. 6), and an inverter unit (540 in FIG. 6) on one circuit board. have. Such a power conversion module (700 in FIG. 6) may be referred to as a micro inverter.

On the other hand, in the embodiment of the present invention, a plurality of solar modules (50a, 50b, ..., 50n), each solar cell module (100a, 1000b, ..., 100n) and the junction box (200a, 200b) , ...,200n), it is possible to output AC power directly, so it may be called a solar AC module.

On the other hand, according to this configuration, by attaching a micro inverter that outputs AC power to each solar cell module (100a, 1000b, ..., 100n), even if the output of any one of the solar cell modules is lowered, a plurality of The photovoltaic modules 50a, 50b, ..., 50n are connected in parallel to each other, so that it is possible to supply AC power generated by a grid (grid).

In addition, unlike the string method in which a plurality of photovoltaic modules (50a, 50b, ..., 50n) are connected in series with each other, AC power is generated and output independently of each other and is connected in parallel. Regardless of the output, it is possible to stably output AC power to the system.

On the other hand, in an embodiment of the present invention, the transformer of the plurality of interleaving converters in the power conversion module (700 in FIG. 6) has a hollow, and a bobbin including a winding guide portion for guiding a winding wound on the side, is inserted into the hollow. A first core having a first protrusion portion, and first and second side portions spaced apart from each other surrounding the bobbin, a second protrusion portion inserted into the hollow, and third and fourth side portions spaced apart from each other surrounding the bobbin And a second core coupled to the bobbin together with the first core, and a winding wound around a winding guide portion in the bobbin. This enables high-efficiency power conversion at the time of power conversion. This will be described later with reference to FIG. 11 or less.

FIG. 2 is a front view of a solar module according to an embodiment of the present invention, FIG. 3 is a rear view of the solar module of FIG. 2, and FIG. 4 is an exploded perspective view of the solar cell module of FIG. 2.

2 to 4, the solar module 50 according to the embodiment of the present invention includes a solar cell module 100 and a junction box 200 positioned on one surface of the solar cell module 100. . In addition, the solar module 50 may further include a heat dissipation 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. In addition, the first sealing material 120 and the second sealing material 150 located on the lower and upper surfaces of the plurality of solar cells 130, the rear substrate 110 and the second located on the lower surface of the first sealing material 120 A front substrate 160 positioned on the upper surface of the sealing material 150 may be further included.

First, the solar cell 130 is a semiconductor device that converts solar energy into electrical energy, and includes a silicon solar cell, a compound semiconductor solar cell, and a stacked solar cell. It may be a tandem solar cell, a dye-sensitized type, or a CdTe, a CIGS type solar cell, or the like.

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

Each solar cell 130 may be electrically connected in series or in parallel or in series-parallel. Specifically, the plurality of solar cells 130 may be electrically connected by the 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 current collecting electrode formed on the rear surface of another adjacent solar cell 130.

In the drawing, the ribbon 133 is formed in two rows, and the solar cells 130 are connected in a row by the ribbon 133 to form a solar cell string 140. As a result, six strings 140a, 140b, 140c, 140d, 140e, and 140f are formed, and each string includes 10 solar cells. Unlike the drawings, various modifications are possible.

Meanwhile, each solar cell string may be electrically connected by a bus ribbon. FIG. 2 shows the first solar cell string 140a and the second solar cell string 140b, respectively, by the bus ribbons 145a, 145c, and 145e disposed under the solar cell module 100, respectively. It is exemplified that the battery string 140c and the fourth solar cell string 140d are electrically connected to the fifth solar cell string 140e and the sixth solar cell string 140f. In addition, FIG. 2 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 solar cell module 100. The battery string 140d and the fifth solar cell string 140e are electrically connected to each other.

Meanwhile, the ribbon connected to the first string, the bus ribbon 145b and 145d, and the ribbon connected to the fourth string are electrically connected to the first to fourth conductive lines 135a, 135b, 135c, and 135d, respectively. , The first to fourth conductive lines 135a, 135b, 135c, and 135d are provided with bypass diodes (Da, Db, and Dc in FIG. 6) in the junction box 200 disposed on the rear surface of the solar cell module 100. Connected. In the drawings, the first to fourth conductive lines 135a, 135b, 135c, and 135d extend to the rear surface of the solar cell module 100 through an opening formed on the solar cell module 100.

On the other hand, it is preferable that the junction box 200 is disposed closer to an end of the solar cell module 100 from which a conductive line extends.

2 and 3, since the first to fourth conductive lines 135a, 135b, 135c, and 135d extend from the top of the solar cell module 100 to the rear surface of the solar cell module 100, the junction box 200 ) Is located at the top of the rear surface of the solar cell module 100. Accordingly, the length of the conductive line can be shortened, so that power loss can be reduced.

The rear substrate 110, as a back sheet, has waterproof, insulating, and UV-blocking functions, and may be a TPT (Tedlar/PET/Tedlar) type, but is not limited thereto. In addition, although the rear substrate 110 is shown in a rectangular shape in FIG. 4, it may be manufactured in various shapes such as a circular shape or a semi-circular shape according to an environment in which the solar cell module 100 is installed.

On the other hand, on the rear substrate 110, the first sealing material 120 may be attached to the same size as the rear substrate 110 and formed, and on the first sealing material 120, a plurality of solar cells 130 They can be located adjacent to each other to achieve.

The second sealing material 150 may be positioned on the solar cell 130 and bonded to the first sealing material 120 by lamination.

Here, the first sealing material 120 and the second sealing material 150 allow the elements of the solar cell to be chemically bonded. The first sealing material 120 and the second sealing material 150 may be various examples such as an ethylene vinyl acetate (EVA) film.

On the other hand, the front substrate 160 is positioned on the second sealing material 150 to transmit sunlight, and is preferably a tempered glass to protect the solar cell 130 from external impacts. In addition, in order to prevent reflection of sunlight and increase the transmittance of sunlight, it is more preferable to use a low iron tempered glass containing less iron.

The junction box 200 is attached on the rear surface of the solar cell module 100 and may convert power using DC power supplied from the solar cell module 100. Specifically, the junction box 200 may include a power conversion module 700 that converts DC power into AC power and outputs it.

The power conversion module 700 may include a bypass diode (Da, Db, Dc), a converter unit (530 in FIG. 6), and an inverter unit (540 in FIG. 6) on one circuit board. Such, the power conversion module 700 may be referred to as a micro inverter.

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

On the other hand, an opening (not shown) is formed in the junction box 200, so that the first to fourth conductive lines 135a, 135b, 135c, and 135d described above are connected to the bypass diodes (Da, Db, and in FIG. 6) in the junction box. Dc) can be connected.

Meanwhile, an AC output cable 38 for outputting the converted AC power to the outside may be connected to one side of the junction box 200.

Meanwhile, the solar module 50 may include a frame 105 for fixing an outer portion of the solar cell module 10. Meanwhile, it is preferable that the thickness h2 of the junction box 200 is smaller than the thickness h1 of the frame 105 so that the junction box 200 does not protrude from the rear surface.

5 is an example of a configuration of a bypass diode of the solar module of FIG. 2.

Referring to the drawings, the bypass diodes Da, Db, and Dc may be connected to the 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 in 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 0.6V generated in a normal solar cell is generated, the potential of the cathode electrode is approximately 12V (=0.6V*20) compared to the potential of the anode electrode of the first bypass diode Da. It becomes higher. That is, the first bypass diode Da performs a normal operation rather than a bypass.

On the other hand, in a solar cell of the first solar cell string 140a, when a hot spot occurs due to shading or adhesion of foreign substances, the voltage generated in one solar cell is approximately 0.6V. A reverse voltage (approximately -15V) is generated, not the voltage of. Accordingly, the potential of the anode electrode of the first bypass diode Da is approximately 15V higher than that of the cathode electrode, and the first bypass diode Da performs a bypass operation. Accordingly, the voltage generated by the solar cells 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 occurs in some solar cells, by bypassing, it is possible to prevent destruction of the solar cell or the like. In addition, it is possible to supply the generated DC power except for the hotspot area.

Next, the second bypass diode Db is connected between the first bus ribbon 145a and the second bus ribbon 145b, and in 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 reversed from the first solar cell string 140a or the second solar cell string 140b. When voltage is generated, the first solar cell string and the second solar cell string are bypassed.

On the other hand, unlike FIG. 5, it is possible to connect six bypass diodes corresponding to six solar cell strings, and other various modifications are possible.

6 is an example of a block diagram of a power conversion module inside the junction box of FIG. 2.

Referring to the drawings, the power conversion module 700 inside the junction box may include a bypass diode unit 510, a converter unit 530, a capacitor C1, an inverter unit 540, and a control unit 550. have.

The bypass diode unit 510 includes bypass diodes Dc, Db, and Da respectively disposed between the first to fourth conductive lines 135a, 135b, 135c, and 135d of the solar cell module 100. It can be provided. At this time, the number of bypass diodes is one or more, and it is preferable that one is smaller than the number of conductive lines.

Bypass diodes (Dc, Db, Da) from the solar cell module 50, in particular, from the first to fourth conductive lines (135a, 135b, 135c, 135d) in the solar cell module 50, the solar direct current Receive power. In addition, the bypass diodes Dc, Db, and Da can be bypassed when a reverse voltage is generated from the DC power from at least one of the first to fourth conductive lines 135a, 135b, 135c, and 135d. have.

Meanwhile, the input power Vpv passed through the bypass diode unit 510 is input to the converter unit 530.

The converter unit 530 converts the input power Vpv output from the bypass diode unit 510. Meanwhile, the converter unit 530 may be referred to as a first power conversion unit.

For example, as shown in FIG. 8A, the converter unit 530 may convert the DC input power Vpv into a pseudo DC voltage. Accordingly, the pseudo DC power may be stored in the capacitor C1. Meanwhile, both ends of the dc terminal capacitor C1 may be referred to as a dc terminal, and the capacitor C1 may be referred to as a dc terminal capacitor.

As another example, the converter unit 530 may boost DC input power Vpv and convert it into DC power, as shown in FIG. 8A. Accordingly, the boosted DC power may be stored in the DC terminal capacitor C1.

The inverter unit 540 may convert DC power stored in the DC terminal capacitor C1 into AC power. Meanwhile, the inverter unit 540 may be referred to as a second power conversion unit.

For example, the inverter unit 540 may convert a pseudo DC voltage converted by the converter unit 530 into AC power.

As another example, the inverter unit 540 may convert the DC power boosted by the converter unit 530 into AC power.

Meanwhile, it is preferable that the converter unit 530 includes a plurality of interleaving converters to convert a pseudo DC voltage or convert a boosted current power source.

In particular, in the embodiment of the present invention, it is assumed that the converter unit 530 includes three or more interleaving converters.

In the drawing, n converters 610a, 610b, ... 610n are connected in parallel with each other. The energy conversion capacity of the n converters 610a, 610b, ... 610n may be the same.

The current by the DC input power supply (Vpv) decreases to 1/N in n converters 610a, 610b,...610n, and at the output terminals of n converters 610a, 610b,...610n, The output current of each converter is summed into one.

On the other hand, n converters (610a, 610b,...610n) are interleaved, and the current phase of each of the n converters (610a, 610b,...610n) is +(360°/N) compared to the reference phase. ), -(360°/N) or a phase delay close thereto.

In this way, when the n number of converters are interleaved, the ripple of the input current and the output current of the converter unit 530 is reduced, and thus, the capacity and size of the circuit elements in the power conversion module 700 are reduced. There is an advantage. Accordingly, the thickness of the junction box may be smaller than the thickness of the frame 105 of the solar cell module.

Meanwhile, as the interleaving converter, a tap inductor boost converter, a flyback converter, or the like may be used.

7A is an example of an internal circuit diagram of the power conversion module of FIG. 6.

Referring to the drawings, the power conversion module 700, a bypass diode unit 510, a converter unit 530, a dc terminal capacitor (C1), an inverter unit 540, a control unit 550, and a filter unit 560 ) Can be included.

7A illustrates a tapped-inductor boost converter as an interleaving converter. In the drawing, it is illustrated that the converter unit 530 includes a first tap inductor boost converter to a third tap inductor boost converter 611a, 611b, ... 611c.

The bypass diode unit 510 includes first to fourth conductive lines 135a, 135b, 135c, and 135d disposed between the nodes a, b, c, and d respectively corresponding to the first to fourth conductive lines 135a, 135b, 135c, and 135d. It includes a third bypass diode (Da, Db, Dc).

The converter unit 530 may perform power conversion using the DC power Vpv output from the bypass diode unit 510.

In particular, the first to third tap inductor boost converters 611a, 611b, ... 611c output the converted DC power to the dc terminal capacitor C1 by interleaving operation.

Among these, the first tap inductor boost converter 611a is connected to the tap inductor T1, the switching element S1 connected between the tap inductor T1 and the ground terminal, and to the output terminal of the tap inductor to perform one-way conduction. It includes a diode D1. Meanwhile, between the output terminal of the diode D1, that is, the cathode and the ground terminal, the dc terminal capacitor C1 is connected.

Specifically, the switching element S1 may be connected between the tap and the ground terminal of the tap inductor T. And, the output terminal (secondary side) of the tapped inductor T is connected to the anode of the diode D1, and the dc terminal capacitor C1 is connected between the cathode and the ground terminal of the diode D1. do.

Meanwhile, the primary side and the secondary side of the tapped inductor T have opposite polarities. Meanwhile, the tap inductor T may be referred to as a switching transformer.

Meanwhile, the primary side and the secondary side of the tapped inductor T are connected to each other as shown in the figure. Accordingly, the tapped inductor boost converter may be a non-insulated type converter.

On the other hand, when three tap inductor boost converters 611a, 611b, and 611c are connected in parallel to each other and driven in an interleaving method as shown in the figure, since the input current component is branched in parallel, each tap inductor boost converter ( The ripple of the current component output through 611a, 611b, and 611c is reduced.

On the other hand, each tap inductor boost converter 611a, 611b, and 611c can operate adaptively in response to the power required value of the output AC power source.

For example, when the power required value is approximately 90W to 130W, only the first converter 611a operates, or when the power required value is approximately 190W to 230W, only the first and second converters 611a and 611b operate, or When the required value is approximately 290W to 330W, all of the first to third interleaving converters 611a, 611b, and 611c can operate. That is, each tap inductor boost converter 611a, 611b, and 611c may selectively operate. Such an optional operation may be controlled by the controller 550.

The inverter unit 540 converts the DC power level-converted by the converter unit 530 into an AC power source. In the drawing, a full-bridge inverter is illustrated. That is, the upper and lower arm switching elements (Sa, Sb) and lower arm switching elements (S'a, S'b), which are respectively connected in series with each other, become a pair, and a total of two pairs of upper and lower arm switching elements are parallel to each other (Sa&S'a, Sb&S'b). Diodes are connected in reverse parallel to each of the switching elements Sa, S'a, Sb, S'b.

The switching elements in the inverter unit 540 are turned on/off based on the inverter switching control signal from the control unit 550. As a result, an AC power source having a predetermined frequency is output. Preferably, it is desirable to have the same frequency (approximately 60 Hz or 50 Hz) as the alternating current frequency of the grid.

The filter unit 560 performs lowpass filtering, understanding smoothing the AC power output from the inverter unit 540. To this end, in the drawings, inductors Lf1 and Lf2 are illustrated, but various examples are possible.

On the other hand, the converter input current detection unit (A) detects the input current (ic1) input to the converter unit 530, the converter input voltage detection unit (B), the input voltage input to the converter unit 530 ( vc1) is detected. The sensed input current ic1 and input voltage vc1 may be input to the controller 550.

On the other hand, the converter output current detection unit (C) detects the output current (ic2) output from the converter unit 530, that is, the dc end current, and the converter output voltage detection unit (D) is, in the converter unit 530 It detects the output voltage (vc2), that is, the dc voltage. The sensed output current ic2 and output voltage vc2 may be input to the controller 550.

On the other hand, the inverter output current detection unit (E) detects the current (ic3) output from the inverter unit 540, the inverter output voltage detection unit (F), the voltage (vc3) output from the inverter unit 540 Is detected. The sensed current ic3 and voltage vc3 are input to the controller 550.

Meanwhile, the controller 550 may output a control signal for controlling the switching element S1 of the converter unit 530 of FIG. 7. In particular, the control unit 550 is applied to at least one of the sensed input current (ic1), input voltage (vc1), output current (ic2), output voltage (vc2), output current (ic3), or output voltage (vc3). Based on this, a turn-on timing signal of the switching element S1 in the converter unit 530 may be output.

Meanwhile, the controller 550 may output an inverter control signal that controls each of the switching elements Sa, S'a, Sb, and S'b of the inverter unit 540. In particular, the control unit 550 is applied to at least one of the sensed input current (ic1), input voltage (vc1), output current (ic2), output voltage (vc2), output current (ic3), or output voltage (vc3). Based on this, the turn-on timing signals of each of the switching elements Sa, S'a, Sb, and S'b of the inverter unit 540 may be output.

Meanwhile, the control unit 550 may control the converter unit 530 to calculate a maximum power point for the solar cell module 100 and, accordingly, to output DC power corresponding to the maximum power.

7B is another example of an internal circuit diagram of the power conversion module of FIG. 6.

The power conversion module 700 of FIG. 7B is the same as the power conversion module 700 of FIG. 7A, a bypass diode part 510, a converter part 530, a DC terminal capacitor C1, and an inverter part 540. , A control unit 550, and a filter unit 560 may be included.

However, FIG. 7B illustrates a flyback converter as an interleaving converter in the converter unit 530. In the drawing, it is illustrated that the converter unit 530 includes a first flyback converter to a third flyback converter 612a, 612b, ... 612c.

In particular, the first flyback converter to the third flyback converter 612a, 612b, ... 612c, unlike the non-insulated type tap inductor boost converter, are of the isolated type, and each converted DC power supply by interleaving operation Is output to the dc terminal capacitor (C1).

Among these, the first flyback converter 612a is connected to the transformer (T11), the switching element (S11) connected between the primary side and the ground terminal of the transformer (T11), and the secondary side of the transformer (T11) to conduct one-way conduction. It includes a diode (D11) to perform. Meanwhile, between the output terminal of the diode D11, that is, the cathode and the ground terminal, a dc terminal capacitor C1 is connected. Meanwhile, the primary side and the secondary side of the transformer T11 have opposite polarities.

8A and 8B are diagrams illustrating a method of operating the power conversion module of FIG. 6.

First, referring to FIG. 8A, the converter unit 530 of the power conversion module 700 according to an embodiment of the present invention converts DC power from the solar cell module 100 into a pseudo DC voltage. Can be converted.

As shown in FIG. 7A, when the converter unit 530 is a tap inductor boost converter or the converter unit 530 is a flyback converter as shown in FIG. 7B, full-wave rectification is performed by switching on/off of the switching element S1 or S11. It can be converted into a pseudo DC voltage, which has the same envelope as the DC power supply. Accordingly, the pseudo DC power may be stored in the capacitor C1.

Meanwhile, the inverter 540 receives a pseudo DC voltage, performs a switching operation, and outputs it as AC power. Specifically, by using a pseudo DC voltage, which has the same envelope as the full-wave rectified DC power, it may be converted into AC power having + and-and output. In particular, it can be converted into an AC power source corresponding to the system frequency and output.

Next, referring to FIG. 8B, the converter unit 530 of the power conversion module 700 according to an embodiment of the present invention converts the DC power from the solar cell module 100 to a level, and specifically boosts, It can be converted to a boosted DC power supply.

As shown in FIG. 7A, when the converter unit 530 is a tap inductor boost converter or the converter unit 530 is a flyback converter as shown in FIG. 7B, DC power is supplied by switching on/off of the switching element S1 or S11. (Vp) can be converted into a boosted DC power supply. Accordingly, the boosted DC power may be stored in the capacitor C1.

The inverter 540 receives the boosted DC power, performs a switching operation, and outputs it as AC power. In particular, it can be converted into an AC power source corresponding to the system frequency and output.

9A to 9B are views referenced for explaining the operation of the tapped inductor boost converter of FIG. 7A.

Briefly describing the operation of the first tapped inductor boost converter 611a, when the switching element S1 is turned on, as shown in FIG. 9A, the input voltage Vpv, the primary side of the tapped inductor T1, And a closed loop through the switching element S1, and the first current I1 flows on the closed loop. At this time, since the secondary side of the tapped inductor T1 has a polarity opposite to that of the primary side, the diode D1 cannot conduct and is turned off. Accordingly, energy by the input voltage Ppv is stored in the primary side of the tapped inductor T1.

Next, when the switching element S1 is turned off, as shown in FIG. 9B, the input voltage Vpv, the primary side and the secondary side of the tapped inductor T1, and the diode D1, and the capacitor C1 Through the closed loop (closed loop) is formed, the second current (I2) flows on the closed loop. That is, since the secondary side of the tapped inductor T1 has a polarity opposite to that of the primary side, the diode D1 becomes conductive. Accordingly, the input voltage Ppv and energy stored in the primary and secondary sides of the tapped inductor T1 may be stored in the capacitor C1 through the diode D1.

In this way, the converter unit 530 can output a pseudo DC power supply or a high-efficiency high-voltage DC power supply by using the input voltage Ppv and the energy stored in the primary side and the secondary side of the tapped inductor T1. .

10A and 10B are diagrams referenced for explaining that the converter unit of FIG. 6 outputs a pseudo DC power using an input power source.

6 and 10A, the first to third interleaving converters 610a, 610b, and 610c in the converter unit 530 output a pseudo DC power using an input power Vpv that is DC.

Specifically, the converter unit 530 outputs a pseudo DC power having a peak value of approximately 330V by using a DC power supply of approximately 32V to 36V from the solar cell module 100.

To this end, the control unit 550 determines the duty of the switching elements of the first to third interleaving converters 610a, 610b, and 610c based on the detected input power (Vpv) and the detected output power (Vdc). Decide.

In particular, the lower the input voltage Vpv, the greater the duty of the switching element of the first to third interleaving converters 610a, 610b, and 610c, and the higher the input voltage Vpv, the smaller the duty of the switching element. .

Meanwhile, as the target output power Vdc is lower, the duty of the switching elements of the first to third interleaving converters 610a, 610b, and 610c decreases, and as the target output power Vdc is higher, the duty of the switching elements Becomes larger. For example, when the target output power Vdc has a peak value of approximately 330V, the duty of the switching element may be the greatest.

In Fig. 10A, the pseudo-DC power waveform Vslv outputted by the duty variable is illustrated, and the pseudo-DC power waveform follows the target sine waveform Vsin.

On the other hand, in the present invention, it is assumed that the switching frequency of the converter unit 530 is varied so that the pseudo DC power supply waveform Vslo more accurately follows the full-wave rectified waveform Vsin.

As shown in FIG. 10B, when the switching frequency of the converter unit 530 is fixed, the error ΔE2 between the pseudo DC power waveform Vslf and the target sine wave Vsin is determined by the converter unit 530 of FIG. 10A. When the switching frequency of is varied, it becomes larger than the error ΔE1 between the pseudo DC power waveform Vslv and the target sinusoidal waveform Vsin.

In the present invention, in order to reduce such an error, the switching frequency of the converter unit 530 is varied. That is, the switching frequency of the switching elements of the first to third interleaving converters 610a, 610b, and 610c is varied.

The control unit 550 sets the switching frequency of the converter unit 530 to increase as the rate of change of the target sine wave Vsin increases, that is, the switching period decreases, and the rate of change of the target sine wave Vsin decreases. As the value increases, the switching frequency of the converter unit 530 may be reduced, that is, the switching period may be controlled to increase.

In FIG. 10A, the switching period is set to Ta in the rising section of the target sine wave Vsin, and the switching period is set to be Tb, which is greater than Ta, in the peak section of the target sinusoidal waveform Vsin. . That is, the switching frequency corresponding to the switching period Ta is higher than the switching frequency corresponding to the switching period Tb. Thereby, the error ΔE1 between the pseudo DC power supply waveform Vslv and the target sine waveform Vsin can be reduced.

Meanwhile, it is also possible to describe the switching frequency variation of FIG. 10A as a switching mode technique of a switching element.

11 is a diagram illustrating an example of a converter unit.

Referring to the drawings, the converter unit is connected to a transformer 1110 for converting power according to the switching operation of the switching element S by a ratio of a primary winding and a secondary winding, and a secondary side. It includes a diode element (D) and a capacitor (C) for storing the converted power.

The transformer 1110 of FIG. 11 may be a transformer in the tapped inductor boost converter of FIG. 7A or a transformer in the flyback converter of FIG. 7B.

In this case, the primary and secondary turns of the transformer 1110 may have a ratio of 1:4, and the number of turns may be 4 and 20, respectively. Depending on the turns ratio and the number of turns, the secondary side voltage is boosted by approximately four times compared to the primary side voltage. Accordingly, the tapped inductor boost converter operates as a boost converter capable of boosting voltage.

12 is a perspective view of a bobbin in a transformer according to an embodiment of the present invention, and FIGS. 13 to 17 are views referenced in the description of FIG. 12.

First, referring to FIG. 12, a bobbin of a transformer may include a winding guide part 1317 that has a hollow shape and guides a winding 1610 wound around a side thereof.

The bobbin 1310 is disposed in the output direction of the primary winding 1610 and is disposed in the output direction of at least one first connection terminal 1359 and the secondary winding 1610, which are electrically connected to the circuit board. And, at least one second connection terminal 1349 electrically connected to the circuit board may be further included.

The bobbin 1310 includes an oval-shaped upper frame 1314 with a hollow, an oval-shaped lower frame 1315 spaced apart from the upper frame, and an upper frame 1314 and a lower frame 1315 In between, a winding guide portion 1317 may be disposed.

Meanwhile, the bobbin 1310 may further include first and second protrusions 1316 and 1318 for guiding the winding 1610 on the upper frame 1314.

At this time, the first and second protrusions 1316 and 1318 may be disposed at positions corresponding to the connection terminals 1339 and 1359. That is, it may be disposed on the upper frame 1314 of the position where the radius of curvature is the smallest. Accordingly, when winding the winding, it is possible to guide the winding.

Meanwhile, referring to FIG. 15, on the other hand, the winding 1610 includes a primary winding C01 and a secondary winding CO2. In this case, the primary winding C01 and the secondary winding CO2 are insulated from each other, and an insulating layer may be disposed therebetween.

In the drawing, it is exemplified that the output direction of the primary winding C01 wound around the winding guide portion 1317 and the output direction of the secondary winding 1610 are different from each other. Thereby, each can be connected to the circuit element.

On the other hand, depending on the winding ratio, it is preferable that the thickness of the primary winding 1610 is thicker than the thickness of the secondary winding CO2.

On the other hand, due to the difference in thickness of the windings, as shown in FIGS. 13 to 14, the length between the center of the hollow (Po) and the first connection terminal (1359), and the center of the hollow (Po) and the second connection terminal (1349) ) Can be designed differently.

Meanwhile, the ratio of the windings of the primary winding C01 and the secondary winding CO2 is 1:4, and the number of windings may be 4 and 20, respectively. Depending on the turns ratio and the number of turns, the secondary side voltage is boosted by approximately four times compared to the primary side voltage. Accordingly, the tapped inductor boost converter operates as a boost converter capable of boosting voltage.

Next, referring to FIGS. 13 to 14, the length between the center of the hollow (Po) and the second connection terminal (1349) than the length (le1) between the center of the hollow (Po) and the first connection terminal (1359) It is preferable that (le2) is longer.

For example, the length le1 between the center of the hollow Po and the first connection terminal 1359 may be approximately 20 to 21 mm, and between the center of the hollow Po and the second connection terminal 1349 The length le2 may be approximately 25 to 22 mm.

On the other hand, the length between the center of the hollow (Po) and the side of the bobbin in the direction of the first connection terminal (1359) (le3), between the center of the hollow (Po) and the side of the bobbin in the direction of the second connection terminal (1349) It is preferred that the length le4 is longer.

For example, the length (le3) between the center of the hollow (Po) and the side surface of the bobbin in the direction of the first connection terminal (1359) may be approximately 19 to 20 mm, and the center of the hollow (Po) and the second connection The length le4 between the side surfaces of the bobbin in the direction of the terminal 1349 may be approximately 20 to 21 mm.

Due to the structure of the bobbin, the height of the transformer can be lowered, and thus, in consideration of the thickness h1 of the frame 105 of the solar module, shown in FIG. 3, a power conversion device, that is, a junction box 200 The thickness h2 of) can be designed to be smaller.

16 illustrates a first core 1710 having a first protrusion 1705 inserted into the hollow, and first and second side portions 1707 and 1708 spaced apart from each other surrounding the bobbin 1310. Here, the first core 1710 may be a lower core coupled to the bobbin 1310.

The first side portion 1707 may include a straight portion 1707b and bent portions 1707a and 1707c that are bent on both sides of the straight portion 1707b, and the second side portion 1708 is a straight portion 1708b. ), bent portions 1708a and 1708c that are bent at both sides of the straight portion 1708b may be provided.

17 illustrates a transformer 1800 in which a second core 1720 corresponding to the first core 1710 is coupled to the bobbin 1310 together with the first core 170.

The second core 1720 is an upper core and has a structure corresponding to the first core 1710.

That is, a second protrusion inserted into the hollow, and third and fourth side portions surrounding the bobbin 1310 and spaced apart from each other are provided.

Meanwhile, the first connection terminals 1349 and 1347 are electrically connected to the circuit board 1900, and second connection terminals (not shown) are also electrically connected to the circuit board 1900.

According to the structure of the transformer 1800, compared to the related art, the height, that is, the thickness can be designed to be approximately 15 mm or less, and the power conversion efficiency can be 96% or more. Accordingly, high-efficiency power conversion is possible.

Further, the primary side inductance may be approximately 10 to 20 uH, and the secondary side inductance may be approximately 350 to 400 uH.

The transformer according to the present invention and the power conversion device having the same may not be limited to the configuration and method of the embodiments described as described above, but the embodiments are all or all of the respective embodiments so that various modifications can be made. Some may be selectively combined and configured.

In addition, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. In addition, various modifications are possible by those of ordinary skill in the art, and these modifications should not be understood individually from the technical spirit or prospect of the present invention.

Claims (17)

A converter unit for converting DC power from the solar cell module;
A control unit for controlling the converter unit; And
Including; a capacitor for storing the voltage output from the converter unit,
The converter unit,
A switching element, a transformer performing power conversion by a switching operation of the switching element, and a diode element disposed at an output terminal of the transformer,
The converter unit includes a plurality of interleaving converters,
When the power required value is in the first range, only a first converter among the plurality of interleaving converters operates, and when the power required value is in a second range higher than the first range, the first converter and the first converter among the plurality of interleaving converters 2 Only the converter works,
The transformer,
A bobbin formed with a hollow and including a winding guide portion for guiding a winding wound on a side thereof;
A first core including a first protrusion inserted into the hollow, and first and second side surfaces surrounding the bobbin and spaced apart from each other;
A second core having a second protrusion inserted into the hollow, and third and fourth side portions surrounding the bobbin and spaced apart from each other, and coupled to the bobbin together with the first core; And
And a winding wound around the winding guide in the bobbin,
The winding includes a primary winding and a secondary winding,
The bobbin,
At least one first connection terminal disposed in an output direction of the primary winding and electrically connected to a circuit board; And
And at least one second connection terminal disposed in the output direction of the secondary winding and electrically connected to the circuit board,
The number of turns of the secondary winding is greater than the number of turns of the primary winding,
The thickness of the primary winding is thicker than the thickness of the secondary winding,
The length between the center of the hollow and the second side of the bobbin in the direction of the second connection terminal is longer than the length between the center of the hollow and the first side of the bobbin in the direction of the first connection terminal Power conversion device. The method of claim 1,
The power conversion device, characterized in that the primary winding and the secondary winding have a turns ratio of 1:4, and the number of turns is 4 and 20 turns. The method of claim 1,
Power conversion device, characterized in that the height of the transformer is 15mm or less. The method of claim 1,
The power conversion device, characterized in that the output direction of the primary winding wound on the winding guide portion and the output direction of the secondary winding are different. delete The method of claim 1,
A power conversion device, characterized in that the length between the center of the hollow and the second connection terminal is longer than the length between the center of the hollow and the first connection terminal. delete The method of claim 1,
The bobbin,
Further comprising the first and second frames of an oval shape in which a hollow is formed,
Power conversion device, characterized in that the winding guide portion is disposed between the first and second frames. The method of claim 8,
The bobbin,
And first and second protrusions formed on the first frame and configured to guide the winding.
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