KR20180099244A - Power converting device and and photovoltaic module including the same - Google Patents

Abstract

The present invention relates to a power conversion device, and a photovoltaic module having the same. According to an embodiment of the present invention, the power conversion device comprises: a converter unit converting a level of an input first DC power source; an inverter unit converting a second DC power source from the converter unit into an AC power source; and a control unit controlling the converter unit and the inverter unit. The converter unit includes: a first switching device and a second switching device connected in series with each other; a transformer connected to the second switching device of the first switching device and the second switching device by a half bridge; a first inductor connected between the first switching element and the second switching element and having the first DC power source inputted thereto; and a second inductor and a boost capacitor connected in series with each other between both ends of the first switching element. As a result, a switching loss can be reduced within the power conversion device of a second stage.

Description

[0001] DESCRIPTION [0002] POWER CONVERSION DEVICE AND PHOTOVOLTAIC MODULES [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion device and a solar module having the same, and more particularly, to a power conversion device capable of reducing switching loss in a two-stage power conversion device, .

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.

Meanwhile, the photovoltaic module means that the solar cells for solar power generation are connected in series or in parallel.

On the other hand, when AC power is output to the grid using an inverter in a solar module, it is desirable to reduce the loss of output power. Accordingly, a method for reducing the loss of output power output from the solar module has been researched.

An object of the present invention is to provide a power conversion device capable of reducing switching loss in a two-stage power conversion device, and a solar module having the power conversion device.

It is another object of the present invention to provide a power conversion device capable of efficiently improving the power factor by constituting a multi-stage boosting in a two-stage power conversion device, and a solar module having the power conversion device.

According to an aspect of the present invention, there is provided a power conversion apparatus including a converter unit for converting a level of an input first DC power source, an inverter unit for converting a second DC power source from the converter unit into an AC power source, And a control unit for controlling the converter unit and the inverter unit, wherein the converter unit includes a first switching device and a second switching device, which are connected in series with each other, and a second switching device of the first switching device and the second switching device, A first inductor connected between the first switching device and the second switching device and to which the first DC power is input; and a second inductor connected in series between the two ends of the first switching device, And a boost capacitor.

According to another aspect of the present invention, there is provided a power conversion apparatus including a converter unit for converting a level of an input first DC power supply, a converter unit for converting a second DC power from the converter unit into an AC power And a control unit for controlling the converter unit and the inverter unit, wherein the converter unit includes: a boost converter for first boosting the first DC power; and a half bridge converter for boosting the first boosted power from the boost converter secondarily .

According to an aspect of the present invention, there is provided a solar module including a solar cell module having a plurality of solar cells, a converter unit for converting a level of an input first DC power source, And a control unit for controlling the converter unit and the inverter unit. The converter unit includes a first switching device and a second switching device, which are connected in series with each other, and a first switching device, A first inductor connected between the first switching device and the second switching device and to which the first DC power is inputted, and a second inductor connected between the first switching device and the second switching device, And a power conversion device including a boost capacitor and a second inductor connected in series to each other between both ends of the power conversion device.

According to another aspect of the present invention, there is provided a solar module including a solar cell module including a plurality of solar cells, a converter unit for converting a level of an input first DC power source, And a control unit for controlling the converter unit and the inverter unit, wherein the converter unit includes: a boost converter for primarily boosting the first DC power; and an inverter for boosting the first DC power from the boost converter And a half bridge converter for boosting the boosted power secondarily.

A power conversion apparatus and a solar module having the same according to the embodiment of the present invention includes a converter section for converting a level of an input first DC power supply and a converter section for converting a second DC power supply from the converter section to an AC power supply And a control unit for controlling the converter unit and the inverter unit, wherein the converter unit includes a first switching device and a second switching device, which are connected in series with each other, and a second switching device among the first switching device and the second switching device, A first inductor connected between the first switching device and the second switching device and to which the first DC power is input and a second inductor connected in series between the two ends of the first switching device, By including the second inductor and the boost capacitor, it is possible to reduce the switching loss in the two-stage power converter.

On the other hand, the first switching element can perform zero voltage switching based on the current flowing in the first inductor, the current flowing in the second inductor, and the current flowing in the third inductor, The switching loss in the device can be reduced.

In particular, the level of the current flowing through the blocking capacitor can be larger than the current flowing through the first inductor due to the second inductor in the converter section, and a path through which a reverse current flows in the first switching element is formed, Voltage switching at the time of switching. This makes it possible to reduce the switching loss in the two-stage power conversion apparatus.

On the other hand, since the DC component is removed from the transformer due to the blocking capacitor, the operation efficiency of the transformer can be improved.

On the other hand, due to the voltage doubler, the voltage on the output side of the transformer can be boosted again, so that the power factor can be efficiently improved.

On the other hand, since the inverter section operates in the dual-buck modulation mode, the number of switching times or the switching frequency is reduced to about half by the bipolar method, and consequently, the switching loss in the inverter section is also reduced. Further, since the current ripple of the output current is improved, it is possible to reduce the size of the filter portion and to reduce the total harmonic distortion (THD).

According to another aspect of the present invention, there is provided a power conversion apparatus and a solar module including the same, including: a converter section for converting a level of an input first DC power supply; And a control unit for controlling the converter unit and the inverter unit, wherein the converter unit includes: a boost converter for primarily boosting the first DC power; a half-boosting unit for boosting the first boosted power from the boost converter; By including the bridge converter, multi-stage boosting can be configured, and the power factor can be improved efficiently.

Meanwhile, according to another embodiment of the present invention, the power converter and the solar module including the power converter can boost the voltage on the output side of the transformer due to the voltage doubler, thereby improving the power factor more efficiently .

FIG. 1A is a diagram illustrating an example of a solar light system including a solar module according to an embodiment of the present invention.
1B is a view showing another example of a solar optical system including a solar module 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;
Fig. 4 is a circuit diagram showing the interior of the junction box in the solar module of Fig. 2. Fig.
5A to 5B show various examples of the power conversion device of the photovoltaic module.
6 is a circuit diagram of a power conversion device in a solar module according to an embodiment of the present invention.
7A to 13 are views referred to the description of the power conversion apparatus of FIG.
Figs. 14A to 14B are diagrams for explaining that the power conversion apparatus of Fig. 6 is mounted on a solar module.
FIG. 15 is an exploded perspective view of the solar cell module of FIG. 2. FIG.

In this specification, a method for controlling a power factor, which is a phase difference between an alternating current and an alternating voltage output from a solar module, is proposed as a method for reducing the loss of output power output from the solar module.

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. 1A is a diagram illustrating an example of a solar light system including a solar module according to an embodiment of the present invention.

Referring to the drawings, a solar light system 10a according to an embodiment of the present invention may include a solar module 50 and a gateway 80. [

The solar module 50 may include a solar cell module 100 and a junction box 200 including a power conversion device 500 (see FIG. 6) for power-converting the DC power from the solar cell module have.

In the drawing, the junction box 200 is shown attached to the back surface of the solar cell module 100, but is not limited thereto. It is also possible that the junction box 200 is provided separately from the solar cell module 100.

On the other hand, a cable oln for supplying the AC power outputted from the junction box 200 to the grid can be electrically connected to the output terminal of the junction box 200. [

Meanwhile, a gateway 80 may be located between the junction box 200 and the grid 90.

On the other hand, the gateway 80 can detect the alternating current io and the alternating voltage vo outputted from the solar module 50 flowing through the cable oln.

On the other hand, the gateway 80 can output a power factor adjustment signal for power factor adjustment based on the phase difference between the alternating current io and the alternating voltage vo output from the solar module 50. [

For this purpose, the gateway 80 and the solar module 50 can perform power line communication (PLC communication) using the cable 323.

On the other hand, the power conversion apparatus (500 of FIG. 6) in the solar module 50 can convert the DC power output from the solar cell module 100 into AC power and output it.

To this end, a converter unit (530 of FIG. 6) and an inverter unit (540 of FIG. 6) may be provided in the power conversion device (500 of FIG. 6) in the solar module 50.

In the present invention, the level of the direct current power from the solar cell module 100 is converted through the converter unit 530 in the power conversion apparatus 500 (FIG. 6), and thereafter, through the inverter unit 540, A two stage stage power conversion device that performs AC power conversion is described.

On the other hand, the present invention proposes a method of reducing loss of output power in a two stage stage power conversion apparatus. Particularly, a method of configuring the converter section 530 having a switching element to be zero voltage switching (ZVS) is proposed.

Further, when level conversion is performed using a single converter circuit at the level conversion of the converter unit 530, the power factor pf tends to deteriorate as the level change amount increases, so that multi- To improve the power factor.

1B is a view showing another example of a solar optical system including a solar module according to an embodiment of the present invention.

Referring to the drawings, a solar light system 10b according to an embodiment of the present invention may include a plurality of solar modules 50a, 50b, ..., 50n and a gateway 80. [

The solar cell system 10b of Fig. 1b differs from the solar cell system 10a of Fig. 1a in that a plurality of solar modules 50a, 50b, ..., 50n are connected in parallel with each other.

Each of the plurality of solar modules 50a, 50b, ..., 50n includes a solar cell module 100a, 100b, ..., 100n and a circuit for converting and outputting DC power from the solar cell module And junction boxes 200a, 200b, ..., 200n including devices.

In the drawing, the junction boxes 200a, 200b, ..., 200n are attached to the back surfaces of the solar cell modules 100a, 100b, ..., 100n, but the present invention is not limited thereto. It is also possible that the junction boxes 200a, 200b, ..., 200n are provided separately from the respective solar cell modules 100a, 100b, ..., 100n.

On the other hand, cables 31a, 31b, ..., oln for supplying AC power outputted from the junction boxes 200a, 200b, ..., 200n to the grid are connected to the junction boxes 200a, 200b, ..., ..., 200n, respectively.

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

Referring to the drawings, a solar module 50 according to an embodiment of the present invention may include a solar cell module 100 and a junction box 200 located on the back surface of the solar cell module 100.

The junction box 200 may include at least one bypass diode that is bypassed to prevent hot spots in the case of shadow generation or the like.

4 and the like, three bypass diodes (Da, Db, and Dc in FIG. 4) are provided corresponding to the four solar cell strings in FIG.

On the other hand, the junction box 200 can convert DC power supplied from the solar cell module 100. This will be described with reference to FIG. 4 and subsequent figures.

On the other hand, the solar cell module 100 may include a plurality of solar cells.

In the figure, a plurality of sinker cells are connected in series by ribbons (133 in FIG. 15) to form a 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. 2 is a sectional view showing the first solar cell string 140a and the second solar cell string 140b by the bus ribbons 145a, 145c and 145e disposed at the lower part of 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.

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 upper part 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 to fourth conductive lines (not shown) 4 conductive lines (not shown) are connected to the bypass diode (Da, Db, and Dc in FIG. 4) in the junction box 200 disposed on the back surface of the solar cell module 100 through openings formed in the solar cell module 100 ).

At this time, the opening formed in the solar cell module 100 may be formed corresponding to the region where the junction box 200 is located.

Fig. 4 is a circuit diagram showing the interior of the junction box in the solar module of Fig. 2. Fig.

Referring to the drawings, the junction box 200 can convert DC power from the solar cell module 100 and output the converted power.

Particularly, in connection with the present invention, the junction box 200 may include a power conversion device for outputting an AC power source.

To this end, the junction box 200 may include a converter unit 530, an inverter unit 540, and a control unit 550 for controlling the converter unit 530 and the junction unit 540.

The junction box 200 may further include a bypass diode 510 for bypassing, a capacitor 520 for storing DC power, and a filter 570 for filtering the AC power have.

The junction box 200 may further include a communication unit 580 for communication with an external gateway 80.

On the other hand, the junction box 200 includes an input current detection unit A, an input voltage detection unit B, a converter output current detection unit C, a converter output voltage detection unit D, an inverter output current detection unit E, And may further include a detection unit F.

On the other hand, the control unit 550 can control the converter unit 530, the inverter unit 540, and the communication unit 580.

The bypass diode 510 may include bypass diodes Dc, Db, and Da disposed between the first through fourth conductive lines (not shown) of the solar cell module 100, respectively . At this time, it is preferable that the number of the bypass diodes is one or more and smaller than the number of the conductive lines by one.

The bypass diodes Dc, Db and Da receive the solar direct current power from the solar cell module 100, particularly from the first to fourth conductive lines (not shown) in the solar cell module 100. The bypass diodes Dc, Db, and Da can be bypassed when a reverse voltage is generated in the DC power supply from at least one of the first to fourth conductive lines (not shown).

On the other hand, the DC power source through the bypass diode 510 can be input to the capacitor 520.

The capacitor unit 520 may store an input DC power input through the solar cell module 100 and the bypass diode unit 510. [

In the figure, the capacitor unit 520 includes a plurality of capacitors Ca, Cb, and Cc connected in parallel to each other. Alternatively, a plurality of capacitors may be connected in series- It is also possible to connect to the terminal. Alternatively, it is also possible that the capacitor unit 520 includes only one capacitor.

The converter unit 530 can convert the level of the input voltage from the solar cell module 100 via the bypass diode unit 510 and the capacitor unit 520. [

In particular, the converter unit 530 can perform power conversion using the DC power stored in the capacitor unit 520.

Meanwhile, the converter unit 530 according to the embodiment of the present invention will be described in detail with reference to FIG.

On the other hand, the switching elements in the converter unit 530 can be turned on / off based on the converter switching control signal from the control unit 550. [ Thereby, the level-converted DC power can be outputted.

The inverter unit 540 can convert the DC power converted by the converter unit 530 into AC power.

In the drawing, a full-bridge inverter is illustrated. Namely, the upper arm switching elements SW1 and SW3 and the lower arm switching elements SW2 and SW4 are paired in series and the two pairs of upper and lower arm switching elements are connected in parallel to each other (SW1 and SW2, SW3 and SW4) Lt; / RTI > Diodes may be connected in anti-parallel to each of the switching elements SW1 to SW4.

The switching elements SW1 to SW4 in the inverter unit 540 can be turned on and off based on the inverter switching control signal from the control unit 550. [ As a result, an AC power source having a predetermined frequency can be output. Preferably, it has a frequency (approximately 60 Hz or 50 Hz) that is equal to the alternating frequency of the grid.

On the other hand, the capacitor C may be disposed between the converter unit 530 and the inverter unit 540.

The capacitor C may store the level-converted DC power of the converter unit 530. [ On the other hand, both ends of the capacitor C may be referred to as a dc stage, and accordingly, the capacitor C may be called a dc-stage capacitor.

The input current detection unit A may sense the input current ic1 supplied from the solar cell module 100 to the capacitor unit 520. [

The input voltage detecting unit B may sense the input voltage Vc1 supplied from the solar cell module 100 to the capacitor unit 520. [ Here, the input voltage Vc1 may be equal to the voltage stored across the capacitor unit 520. [

The sensed input current ic1 and the input voltage vc1 may be input to the control unit 550. [

The converter output current detector C senses the output current ic2 output from the converter 530 or the dc converter current and the converter output voltage detector D outputs the output current ic2 output from the converter 530 And detects the output voltage vc2, i.e., the dc voltage. The sensed output current ic2 and the output voltage vc2 may be input to the control unit 550. [

On the other hand, the inverter output current detection unit E detects the current ic3 output from the inverter unit 540, and the inverter output voltage detection unit F detects the voltage vc3 output from the inverter unit 540 do. The detected current ic3 and the voltage vc3 are input to the control unit 550. [

Meanwhile, the control unit 550 may output a control signal for controlling the switching elements of the converter unit 530. In particular, the control unit 550 controls the control unit 550 so that at least one of the detected input current ic1, the input voltage vc1, the output current ic2, the output voltage vc2, the output current ic3, or the output voltage vc3 On timing signals of the switching elements in the converter unit 530 can be output.

On the other hand, the control unit 550 can output an inverter control signal for controlling each of the switching elements SW1 to SW4 of the inverter unit 540. In particular, the control unit 550 controls the control unit 550 so that at least one of the detected input current ic1, the input voltage vc1, the output current ic2, the output voltage vc2, the output current ic3, or the output voltage vc3 On timing signals of the respective switching elements SW1 to SW4 of the inverter unit 540 can be output based on the above-mentioned signals.

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

On the other hand, the communication unit 580 can perform communication with the gateway 80. [

For example, the communication unit 580 can exchange data with the gateway 80 by power line communication.

On the other hand, the communication unit 580 can receive the power factor adjustment signal Sph from the gateway 80. [

On the other hand, the communication unit 580 may transmit current information, voltage information, power information, and the like of the solar module 50 to the gateway 80. [

On the other hand, the filter unit 570 can be disposed at the output terminal of the inverter unit 540.

The filter unit 570 includes a plurality of passive elements and has a phase between the alternating current io and the alternating voltage vo output from the inverter unit 540 based on at least a part of the plurality of passive elements You can adjust the difference.

5A to 5B show various examples of the power conversion device of the photovoltaic module.

5A includes a capacitor unit 620, a converter unit 630, an inverter unit 640, and a filter unit 670. The power conversion apparatus 600a of FIG.

5A has an interleaved flyback converter. Since the transformers T1a and T1b are used, the input side and the output side are insulated and the voltage conversion ratio is excellent. However, There is a drawback that it is difficult to control the power factor (pf).

Next, the power conversion device 600b of the solar module in Fig. 5B includes a capacitor portion 620b, a power conversion portion 640b, and a filter portion 670b.

The power converter 640b of Fig. 5B further includes a diode Dbb and a switching element Sbb in addition to the switching elements S1b to S4b related to the full bridge inverter.

The power conversion unit 640b of FIG. 5B can control the power factor pf, but it has a low voltage conversion ratio as a non-insulation type, and has a separate protection Circuit and the like are required. In addition, there is a disadvantage in that a hard switching loss occurs due to hard switching at the time of switching, resulting in a low power conversion efficiency.

Correspondingly, in the present invention, the present invention proposes a method of reducing loss of output power in a two stage stage power conversion apparatus. Particularly, a method of configuring the converter section 530 having a switching element to be zero voltage switching (ZVS) is proposed.

Further, when level conversion is performed using a single converter circuit at the level conversion of the converter unit 530, the power factor pf tends to deteriorate as the level change amount increases, so that multi- To improve the power factor.

FIG. 6 is a circuit diagram of a power conversion apparatus in a solar module according to an embodiment of the present invention, and FIGS. 7A to 13 are views referred to the description of the power conversion apparatus of FIG.

Referring to the drawings, a power conversion device 500 in a solar module 100 according to an embodiment of the present invention includes a converter unit 530, an inverter unit 540, a control unit 550, The input current detection unit A, the input voltage detection unit B, the converter output current detection unit C, the converter 530, the converter unit 570, the converter unit 570, the bypass diode unit 510, the capacitor unit 520, An output voltage detection unit D, an inverter output current detection unit E, and an inverter output voltage detection unit F.

Hereinafter, the converter unit 530, the inverter unit 540, the control unit 550, the filter unit 570, and the like shown in FIG. 6 will be mainly described.

The power conversion apparatus 500 in the solar module 100 according to the embodiment of the present invention includes a converter unit 530 for converting the level of the first DC power supply, And a control unit 550 for controlling the converter unit 530 and the inverter unit 540. The converter unit 530 includes a first switching device 530 connected in series to the first switching device 530, A transformer 536 connected to the second switching element S2 of the first switching element S1 and the second switching element S2 by a half bridge and the second switching element S2 and the second switching element S2, A first inductor Lb connected between the first switching device S1 and the second switching device S2 and to which the first DC power is input and a second inductor Lb connected in series between the two ends of the first switching device S1, A second inductor La to be connected, and a boost capacitor Cs. This makes it possible to reduce the switching loss in the two-stage power converter.

The first DC power input to the converter unit 530 may be a DC power from the solar cell module 100 or a DC power from the capacitor 520 or a DC power from the bypass diode 510 .

Meanwhile, the converter unit 530 includes the first switching device S1 and the second switching device S2, the transformer 536, the first inductor Lb, the second inductor La, the boost capacitor Cs , A blocking capacitor Cb, and a third inductor (Lik).

The blocking capacitor Cb is connected between the first switching element S1 and the second switching element S2 and between the second inductor La and can operate to cancel the DC offset. Thus, the operation efficiency of the transformer 536 can be improved.

The third inductor L i may be connected between the second switching element S 2 and the input side of the transformer 536.

On the other hand, the second inductor La in the converter unit 530 can form a path through which a reverse current flows to the first switching element S1.

On the other hand, based on the current ilb flowing in the first inductor Lb, the current flowing in the second inductor La, and the current flowing in the third inductor Lb, Switching (ZVS) can be performed. This makes it possible to reduce the switching loss in the two-stage power conversion apparatus.

On the other hand, the second switching device S2 can perform the zero voltage switching (ZVS) based on the current ilb flowing through the first inductor Lb and the current flowing through the blocking capacitor Cb. This makes it possible to reduce the switching loss in the two-stage power conversion apparatus.

On the other hand, the converter unit 530 includes a first capacitor C1, a second capacitor C2, an output side of the transformer 536, a first capacitor C1 (C1) connected to the output side of the transformer 536, And a second diode D2 connected between the output side of the transformer 536 and the second capacitor C2. The first diode D1 may be connected between the output side of the transformer 536 and the second capacitor C2.

The first capacitor C1 and the second capacitor C2 and the first diode D1 and the second diode D2 can constitute a voltage doubler 538 and the voltage doubler 538 , The voltage on the output side of the transformer 536 can be boosted again, so that the power factor can be efficiently improved.

The circuit inside the converter unit 530 will be described in more detail. The circuit between the first switching device S1 and the second switching device S2 and the input terminal of the converter unit 530, which are connected in series to each other, , And a first inductor Lb may be disposed.

On the other hand, one end of the first switching device S1 may be connected to the ground terminal. The other end of the first switching device S1 and one end of the second switching device S2 may be connected.

On the other hand, a blocking capacitor Cb may be disposed between one end of the input side of the transformer 546 and the first switching device S1 and the second switching device S2.

On the other hand, a second inductor La and a boost capacitor Cs, which are connected in series to each other, may be disposed between one end of the input side of the transformer 546 and one end of the first switching device S1, that is, .

On the other hand, a third inductor (Lik) may be disposed between the other end of the transformer 546 on the input side and the other end of the second switching element S1.

On the other hand, an anode of the first diode D1 may be connected to one end of the output side of the transformer 546, and a cathode of the second diode D1 may be connected to the terminal of the output side of the transformer 546. [

The first capacitor C1 and the second capacitor C2 may be connected in series between the cathode of the first diode D1 and the anode of the second diode D1.

On the other hand, the other end of the output side of the transformer 546 can be connected between the first capacitor C1 and the second capacitor C2.

Next, the inverter unit 540 can be connected between both ends of the first capacitor C1 and the second capacitor C2. The filter unit 570 can be connected to the output terminal of the inverter unit 540.

7A and 7B, the converter unit 530 includes a boost converter 532 for first boosting the first DC power source, a half-boosting unit 530 for boosting the first boosted power from the boost converter 532, Bridge converter 537 as shown in FIG.

The boost converter 532 may include a first switching device S1, and a first inductor Lb. Accordingly, the converter unit 530 can perform primary boosting by operating the boost converter 532 using the first switching device S1 and the first inductor Lb.

The half bridge converter 537 may include a first switching device S1, a second switching device S2, and a transformer 536. [ Accordingly, the converter unit 530 operates as the half bridge converter 537 using the first switching device S1, the second switching device S2, and the transformer 536 to perform secondary boosting .

In this way, multi-stage boosting can be configured, and the power conversion apparatus 500 of FIG. 6 can efficiently improve the power factor.

7A and 7B, the converter unit 530 may further include a voltage doubler 538 for tertiary boosting the secondary boosted power from the bridge converter.

The voltage doubler 538 may include a first capacitor C1 and a second capacitor C2, a first diode D1 and a second diode D2. The converter unit 530 operates with the voltage doubler 538 using the first capacitor C1 and the second capacitor C2, the first diode D1 and the second diode D2 So that third boosting can be performed.

In particular, the first capacitor C1, the second capacitor C2, the first diode D1 and the second diode D2 in the converter unit 530 rectify the output-side power supply of the transformer 536, The tertiary boosting can be performed by inverting the reverse voltage on the output side of the transformer 536. [

On the other hand, since the voltage on the output side of the transformer 536 can be boosted again by the voltage doubler 538, the power factor can be improved more efficiently.

7B, the boost converter 532 may be referred to as a first boosting unit, the half bridge converter 537 may be referred to as a second boosting unit, and the voltage doubler 538 may be referred to as a second boosting unit 3 step-up part.

8A shows a circuit current path in the power inverter 500 at a dead time until the first switching element S1 is turned on after the second switching element S2 is turned off.

Next, Fig. 8B shows the circuit current path in the power inverter 500 when the first switching device S1 is turned on. According to Fig. 8B, it is possible to perform the zero voltage switching (ZVS) based on the current flowing in the second inductor La and the current flowing in the third inductor Lc.

Next, FIG. 8C shows the circuit current path in the power conversion device 500 when the turn-on is continued after the first switching device S1 is turned on.

The energy stored in the boost capacitor Cs is transferred to the output side of the transformer 536 and energy is stored in the blocking capacitor Cb when the first switching element S1 is turned on and the turn- have.

On the other hand, Fig. 8D shows the circuit current path in the power inverter 500 immediately before the turn-on of the first switching device S1. At this time, the current Icb flowing through the blocking capacitor Cb becomes equal to the sum of the current ilik flowing through the third inductor Lc and the current Ila flowing through the second inductor Lb.

On the other hand, FIG. 8E shows circuit current paths in the power inverter 500 when the first switching device S1 is turned on.

At this time, the current Icb flowing through the blocking capacitor Cb is equal to the sum of the current ilik flowing through the third inductor Lik and the current Ila flowing through the second inductor, and is supplied to the blocking capacitor Cb The flowing current Icb becomes larger than the current ilb flowing through the first inductor.

That is, when the first switching device S1 is turned on, the sum of the current ilik flowing through the third inductor Lik and the current Ila flowing through the second inductor is greater than the current ilb flowing through the first inductor .

Therefore, the free wheeling current flows into the body diode of the first switching element S1, and the turn-on becomes possible when the voltage Vs1 across the first switching element S1 becomes zero . Thus, zero voltage switching becomes possible.

8F is a graph showing the relationship between the current I il flowing through the third inductor L i and the current I la flowing through the second inductor L i of the first switching device S 1 and the second switching device S 2, A current Icb flowing in the blocking capacitor Cb, a current ilb flowing in the first inductor, and a current is1 flowing in the first switching device S1.

According to Fig. 8F, the first switching device S1 is turned on and the free wheeling current flows to the body diode of the first switching device S1 at the time point to, so that the zero voltage switching ZVS ).

This zero voltage switching of the first switching device S1 is possible because the second inductor La in the converter section 530 is disposed between the one end of the input side of the transformer 536 and the boost capacitor Cs .

That is, due to the second inductor La, the sum of the current ilik flowing in the third inductor Lik and the current Ila flowing in the second inductor at the time of turning on the first switching element S1, Becomes larger than the current (ilb) flowing in one inductor. Thus, zero voltage switching becomes possible. Therefore, the switching loss can be reduced.

On the other hand, FIG. 9A shows the circuit current path in the power conversion device 500 at the dead time until the second switching device S2 is turned on after the first switching device S1 is turned off.

Next, Fig. 9B shows the circuit current path in the power inverter 500 when the second switching element S2 is turned on. 9B, zero voltage switching ZVS can be performed based on the current ilb flowing through the first inductor Lb and the current Icb flowing through the blocking capacitor Cb.

At this time, energy is stored in the first inductor Lb and the boost capacitor Cs, and energy can be transferred to the output side of the transformer.

Next, FIG. 9C shows the circuit current path in the power conversion device 500 when the turn-on is continued after the second switching device S2 is turned on.

The energy stored in the blocking capacitor Cb can be transmitted to the output side of the transformer 536. In the case where the turn-on is continued after the second switching element S2 is turned on, the energy stored in the blocking capacitor Cb can be transmitted to the output side of the transformer 536. [

On the other hand, FIG. 9D shows the circuit current path in the power conversion device 500 immediately before the turn-on of the second switching device S2. At this time, the current Icb flowing through the blocking capacitor Cb becomes equal to the sum of the current ilik flowing through the third inductor Lc and the current Ila flowing through the second inductor Lb.

On the other hand, FIG. 9E shows the circuit current path in the power inverter 500 when the second switching device S2 is turned on.

At this time, the current Icb flowing through the blocking capacitor Cb is equal to the sum of the current ilik flowing through the third inductor Lik and the current Ila flowing through the second inductor, so that the zero voltage switching is always established do.

9F is a graph showing the relationship between the current I il flowing through the third inductor L i and the current I la flowing through the second inductor L i of the first switching device S 1 and the second switching device S 2, A current Icb flowing in the blocking capacitor Cb, a current ilb flowing in the first inductor, and a current is1 flowing in the first switching device S1.

According to Fig. 9F, at time t1, the second switching device S2 is turned on, and at this time, zero voltage switching (ZVS) is enabled. Therefore, the switching loss can be reduced.

Next, FIGS. 10A to 13 are diagrams referred to explain the dual buck modulation scheme of the inverter unit 540.

10A illustrates that the inverter unit 540 and the filter unit 570 are disposed between both ends of nodes c and d, which are the output terminals of the converter unit 530. [

In the figure, it is exemplified that the first to fourth switching elements SW1 to SW4 in the inverter unit 540 are provided.

10A and 10B are diagrams for explaining the operation of the third switching device SW3 in the inverter section 540 and the first switching device SW1 in the inverter section 540 by a bipolar modulation method And the duty of the switching control signal applied thereto, respectively.

(C) and (d) of FIG. 10 (b) show the third switching device SW3 in the inverter unit 540 and the first switching device SW1 in the inverter unit 540 by a dual buck modulation scheme ) Of the switching control signal, respectively.

Comparing FIGS. 10A and 10B with FIGS. 10B and 10C, the switching frequency in the dual buck modulation scheme is determined by the biopolar modulation method, So that the switching loss in the inverter unit 540 is reduced to about half. Further, since the current ripple of the output current is improved, it is possible to reduce the size of the filter portion and to reduce the total harmonic distortion (THD).

Specifically, FIGS. 10A and 10B are diagrams illustrating a third switching device SW3 in the inverter unit 540 by the bipolar modulation method of FIGS. 10A and 10B, And the first switching device SW1 in the inverter unit 540, respectively.

10C and 10D show waveforms of the voltage waveform Vgrida and the current waveform Igrida output from the inverter section 540 by the waveforms of FIGS. 10A and 10B, respectively For example.

On the other hand, FIGS. 10A and 10B are diagrams for explaining the operation of the third switching element SW3 (FIG. 10B) in the inverter section 540 by the dual buck modulation scheme of FIGS. 10C and 10D ) And the first switching device SW1 in the inverter unit 540, respectively.

10D and 10D show waveforms of the voltage waveform Vgridb and the current waveform Igridb output from the inverter section 540 in accordance with (a) and (b) For example.

10d, the switching loss of FIG. 10d is reduced, and further, the power factor can also be improved from approximately 94% to 97% to 98%.

11A to 11C are diagrams referred to explain the operation of the inverter unit 540 at the time of outputting the positive portion of the AC power source.

In the positive polarity of the AC power supply, the second switching device SW2 is continuously turned on.

First, FIG. 11A illustrates that the second switching device SW2 and the third switching device SW3 are turned on as a charge mode. The current path that flows through the output terminal of the converter section 530, the third switching element SW3, the first inductor L1 of the filter section 570, the second inductor L2 and the second switching element SW2, Can be formed. Accordingly, energy can be accumulated in the first inductor L1.

Next, FIG. 11B illustrates that the second switching device SW2 and the fourth switching device SW4 are turned on as a discharge mode. Accordingly, a current path through the first inductor L1, the second inductor L2, the second switching device SW2, and the fourth switching device SW4 of the filter unit 570 can be formed. Accordingly, the energy stored in the first inductor L1 can be output to the system.

11C, the third switching device SW3 is turned on, the output voltage waveform rises as a charge mode, and as shown in Fig. 11C (c), the fourth switching The element SW4 is turned on, and the output voltage waveform can be lowered as a discharge mode.

12A to 12C are diagrams referred to explain the operation of the inverter unit 540 at the time of negative partial output of the AC power source.

In the positive polarity of the AC power supply, the fourth switching device SW4 is continuously turned on.

First, FIG. 12A illustrates that the first switching device SW1 and the fourth switching device SW4 are turned on as a charge mode. The current path of the current flowing through the output terminal of the converter unit 530, the first inductor L2 of the filter unit 570, the first inductor L1 and the fourth switching unit SW4, Can be formed. Accordingly, energy can be accumulated in the second inductor L2.

Next, FIG. 12B illustrates that the second switching device SW2 and the fourth switching device SW4 are turned on as a discharge mode. Accordingly, a current path through the first inductor L1, the second inductor L2, the second switching device SW2, and the fourth switching device SW4 of the filter unit 570 can be formed. Accordingly, the energy stored in the second inductor L2 can be output to the system.

12C, the first switching device SW1 is turned on, and the output voltage waveform rises as a charge mode. As shown in Fig. 12C (c), the second switching The element SW2 is turned on, and as the discharge mode, the output voltage waveform can fall.

13 shows a block diagram within control 550 for operation of inverter 540 in a dual buck modulation scheme.

The control unit 550 includes a voltage converting unit 1303, a current converting unit 1305, an estimating unit 1310, an axis converting unit 1314, an axis converting unit 1312, a voltage command generating unit 1320, And a signal output unit 1330.

The voltage converting unit 1303 can convert the detected voltage Vou from the inverter output voltage detecting unit F into the two-phase voltages Vds and Vqs.

The current converting unit 1305 can convert the detected current Iou from the inverter output current detecting unit E into the two-phase currents Ids and Iqs.

)을 출력할 수 있다.The estimation unit 1310 estimates a phase based on the two-phase voltages Vds and Vqs from the voltage conversion unit 1303,

Can be output.

)에 기초하여, 정지 좌표계 기반의 2상 전류를 회전 좌표계 기반의 2상 전류(Idc,Iqc)로 변환한다.The axis conversion unit 1314 receives the two-phase currents Ids and Iqs from the current converting unit 1305 and the estimated phase (s) from the estimating unit 1310

Phase currents based on the stationary coordinate system into two-phase currents (Idc, Iqc) based on the rotating coordinate system.

The voltage command generation unit 1320 generates a voltage command based on the rotational coordinate system based on the rotational coordinate system based on the two-phase currents Idc and Iqc, the current command values Idc_ref and Iqc_ref, and the inductance, and outputs the two-phase voltage command values Vhdc and Vhqc Can be output.

)에 기초하여, 전압 지령 생성부(1320)로부터의 회전 좌표계 기반의 2상 전압 지령치(Vhdc,Vhqc)를, 정지 좌표계 기반의 2상 전압 지령치(Vhds)로 변환한다.Then, the axis conversion unit 1312 converts the estimated phase (

Phase voltage command values Vhdc and Vhqc based on the rotation coordinate system from the voltage command generation section 1320 into a two-phase voltage command value Vhds based on the stationary coordinate system.

The switching control signal output section 1330 outputs switching control signals Sic (i) to (iv) that can be input to the gate terminals of the first to fourth switching devices SW1 to SW4, based on the two-phase voltage command value Vhds based on the stationary coordinate system. Can be generated and output.

Accordingly, the first to fourth switching elements SW1 to SW4 in the inverter 540 perform the switching operation. In particular, a switching operation is performed based on a dual buck modulation scheme.

Figs. 14A to 14B are diagrams for explaining that the power conversion apparatus of Fig. 6 is mounted on a solar module.

First, referring to FIG. 14A, the power conversion apparatus 500 of FIG. 6 may be disposed on the upper rear frame FRa of the rear frames FRa to FRd of the solar module 50.

In particular, since the power converter 500 of FIG. 6 is not an interleaved system, only one transformer 536 can be used.

As a result, the configuration of the circuit elements in the power inverter 500 is simplified, and the volume of the power inverter 500 becomes smaller as compared with the case of using two transformers as shown in FIG. 5A.

Therefore, as shown in FIG. 3, the power conversion apparatus 500 does not have to be disposed in the separate junction box 200 on the back surface of the solar module 50. [

As a result, it is possible to be embedded or attached to the upper rear frame FRa of the back frame FRa to FRd of the solar module 50 as shown in the figure.

Specifically, a first cable connecting portion (CNA) and a second cable connecting portion (CNB) are disposed on both sides of the power inverter 500, and the first cable connecting portion CNA, the second cable connecting portion CNB, And the power conversion device 500 may be configured as a power conversion module 400, which is a single module.

That is, the power conversion module 400 may include a first cable connection unit (CNA), a second cable connection unit (CNB), and a power conversion unit 500.

On the other hand, an AC power cable is extended to the first cable connecting portion (CNA) and the second cable connecting portion (CNB), respectively, and can be connected to a power conversion device of an adjacent solar module.

Meanwhile, the power conversion module 400 is coupled to the upper rear frame FRa of the rear frames FRa to FRd of the solar module 50 in a sliding manner from the side, and may be fixed to an opening or the like with a screw or the like . The coupling by the screw method will be described with reference to Fig. 14B.

Fig. 14B illustrates a side view of the solar module 50. Fig.

Referring to the drawing, the power conversion module 400 can be attached to and detached from the upper rear frame FRa. To this end, a coupling member (for example, a screw) may be coupled to the opening formed in the upper rear frame FRa.

In the figure, it is exemplified that the upper rear frame FRa includes a first frame FRaa and a second frame FRab which are intersecting each other as a letter shape.

 A plurality of openings may be formed in each of the first frame FRaa and the second frame FRab and a plurality of screws Scpa, Scpb, Scpc and Scpd may be fastened to the respective openings.

The engagement direction of the first and second screws Scpa, Scpb, Scpc and Scpd among the plurality of screws Scpa, Scpb, Scpc and Scpd and the engagement direction of the third and fourth screws Scpc and Scpd , The fastening force is improved and the power conversion module 400 is firmly fixed to the upper rear frame FRa.

FIG. 15 is an exploded perspective view of the solar cell module of FIG. 2. FIG.

Referring to FIG. 15, the solar cell module 100 of FIG. 2 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.

The solar cell 130 is a semiconductor device that converts solar energy into electrical energy. The solar cell 130 may be a silicon solar cell, a compound semiconductor solar cell, a tandem solar cell, Dye-sensitized or CdTe, CIGS type solar cells, thin film solar cells, and the like.

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.

Thus, as described with reference to FIG. 2, six strings 140a, 140b, 140c, 140d, 140e, and 140f are formed, and each string may include ten solar cells.

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. Although the rear substrate 110 is shown as a rectangular shape in FIG. 4, the rear substrate 110 may be formed in various shapes such as a circular shape and a semicircular shape according to 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 power conversion apparatus and the solar module having the power conversion apparatus according to the present invention are not limited to the configuration and method of the embodiments described above, All or a part of the above-described elements may be selectively combined.

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 (18)

A converter unit for converting a level of an input first DC power supply;
An inverter unit for converting a second DC power from the converter unit to an AC power;
And a control unit for controlling the converter unit and the inverter unit,
The converter unit includes:
A first switching element and a second switching element which are connected in series with each other;
A transformer connected to the second switching device among the first switching device and the second switching device by a half bridge;
A first inductor connected between the first switching device and the second switching device and receiving the first DC power;
A second inductor connected in series between the two ends of the first switching element, and a boost capacitor. The method according to claim 1,
The converter unit includes:
A first capacitor connected to the output side of the transformer by a half bridge; a second capacitor;
A first diode connected between the output side of the transformer and the first capacitor;
And a second diode connected between the output side of the transformer and the second capacitor. The method according to claim 1,
The converter unit includes:
Wherein the first switching device and the first inductor are used as a boost converter to perform primary boosting. The method according to claim 1,
The converter unit includes:
Wherein the first switching device, the second switching device, and the transformer operate as a half bridge converter to perform secondary boosting. 3. The method of claim 2,
The converter unit includes:
Wherein the first capacitor, the first capacitor, the first diode, and the second diode are operated as a voltage doubler to perform third boosting by using the first capacitor, the second capacitor, the first diode, and the second diode. 6. The method of claim 5,
In the converter section,
Wherein the first capacitor, the second capacitor, the first diode, and the second diode rectify the output-side power supply of the transformer, and reverse the output-side reverse voltage of the transformer to perform the third boosting Power converter. The method according to claim 1,
The converter unit includes:
Further comprising a blocking capacitor connected between the first switching device and the second switching device and between the second inductor and operating for DC offset removal. 8. The method of claim 7,
The converter unit includes:
And a third inductor connected between the second switching device and the input side of the transformer. The method according to claim 1,
And the second inductor in the converter section,
Wherein a path through which a reverse current flows is formed in the first switching element. 9. The method of claim 8,
Wherein the first switching element comprises:
And performs zero voltage switching based on a current flowing in the first inductor, a current flowing in the second inductor, and a current flowing in the third inductor. 11. The method of claim 10,
When the first switching element is turned on,
Wherein a sum of a current flowing in the second inductor and a current flowing in the third inductor is larger than a current flowing in the first inductor. 11. The method of claim 10,
The energy stored in the boost capacitor is transferred to the output side of the transformer after the first switching element is turned on, and the energy is stored in the blocking capacitor. 9. The method of claim 8,
And a zero voltage switching is performed based on a current flowing through the first inductor and a current flowing through the blocking capacitor when the second switching element is turned on. 14. The method of claim 13,
And the energy stored in the blocking capacitor is transferred to the output side of the transformer after the second switching element is turned on. The method according to claim 1,
And a filter unit having a plurality of inductors connected to an output terminal of the inverter unit,
Wherein,
Wherein the inverter unit and the filter unit are controlled to operate in a dual-buck modulation scheme. A converter unit for converting a level of an input first DC power supply;
An inverter unit for converting a second DC power from the converter unit to an AC power;
And a control unit for controlling the converter unit and the inverter unit,
The converter unit includes:
A boost converter for primarily boosting the first DC power;
And a half bridge converter for secondarily boosting the primary boosted power from the boost converter. 17. The method of claim 16,
The converter unit includes:
Further comprising: a voltage doubler for tertiary boosting the secondary boosted power from the bridge converter. A solar cell module comprising a plurality of solar cells;
18. A solar module comprising: the power conversion device according to any one of claims 1 to 17.

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