KR20200022166A - Power converting apparatus and photovoltaic module including the same - Google Patents

Abstract

The present invention relates to a power converting device and a photovoltaic module having the same. According to an embodiment of the present invention, the photovoltaic module comprises: an inverter having first and second upper arm switching elements and first and second lower arm switching elements and converting direct current (DC) power into alternating current (AC) power from a converter; and a current detection unit connected between the first lower arm switching element in the inverter and the ground. The first and second upper arm switching elements and the first and second lower arm switching elements in the inverter include a gallium nitride transistor. When the photovoltaic module is regenerated, if the AC power outputted from the inverter is negative, the first lower arm switching element and the second upper arm switching element are turned on. Accordingly, high-speed switching is possible, reverse current during switching is reduced, and current detection during regeneration is enabled.

Description

Power converting apparatus and photovoltaic module having the same {Power converting apparatus and photovoltaic module including the same}

The present invention relates to a power converter and a solar module having the same, and more particularly, to a solar module capable of miniaturizing the power converter.

 The solar module includes a plurality of solar cells, and the solar cells may be connected in series or in parallel.

On the other hand, the power converter of the solar module converts a DC power supply into an AC power supply. In particular, when the power converter is attached to the solar module, there is a demand for miniaturization and high efficiency of the power converter.

On the other hand, the inverter in the power converter requires a high speed operation such as a fault ride through (FRT).

On the other hand, as a method of miniaturization and high efficiency of a power converter, research has been conducted on the replacement of silicon field effect transistors (FETs) to gallium nitride (GaN) transistors as switching elements used in inverters.

An object of the present invention is to provide a power conversion device capable of high-speed switching, the reverse current at the time of switching is reduced, the current detection at the time of regeneration and a solar module having the same.

Another object of the present invention is to provide a power converter capable of miniaturization and a solar module having the same.

In order to achieve the above object, a power converter and a photovoltaic module having the same according to an embodiment of the present invention include first and second phase arm switching elements and first and second lower arm switching elements, and direct current from a converter. An inverter for converting a power source into an alternating current power source, and a current detector connected between the first lower arm switching element and the ground in the inverter, wherein the first and second upper arm switching elements and the first and second lower arm switching elements in the inverter And a gallium nitride transistor, and when regenerating, when the AC power output from the inverter is negative, the first lower arm switching element and the second phase arm switching element are turned on.

On the other hand, when the regenerative AC power output from the inverter is positive, the first phase arm switching element and the first lower arm switching element operate at the first switching frequency, and the second phase arm switching element and the second lower arm switching element are The first phase arm switching element and the first lower arm switching element operate at a second switching frequency when the AC power output from the inverter is negative when the regenerative operation is performed at a second switching frequency lower than the first switching frequency. The first phase arm switching element and the first lower arm switching element operate at a first switching frequency.

On the other hand, when the alternating current power output from the inverter is positive, and the alternating current power output from the inverter is negative, the first phase arm switching element and the first lower arm switching element operate at a first switching frequency. The two phase arm switching element and the second lower arm switching element operate at a second switching frequency lower than the first switching frequency.

On the other hand, when the regenerative AC power output from the inverter is positive, the first phase arm switching element and the first lower arm switching element operate at the first switching frequency, and the second phase arm switching element and the second lower arm switching element are The first and second phase arm switching elements and the first and second lower arm switching elements may operate at a second switching frequency lower than the first switching frequency, and when the regenerative AC power outputted from the inverter is negative, Operate at a frequency.

On the other hand, the power conversion apparatus and a solar module having the same according to another embodiment of the present invention for achieving the above object, the first and second phase arm switching element and the first and second arm arm switching element, and the converter And a current detector connected between the first lower arm switching element in the inverter and the ground, and the first and second upper arm switching elements and the first lower arm switching element in the inverter And a gallium nitride transistor, wherein the second lower arm switching element includes a silicon field effect transistor. When the AC power output from the inverter is negative during regeneration, the first lower arm switching element and the second phase arm switching element include: Turn on.

On the other hand, when the regenerative AC power output from the inverter is positive, the first phase arm switching element and the first lower arm switching element operate at the first switching frequency, and the second phase arm switching element and the second lower arm switching element are The first phase arm switching element and the first lower arm switching element operate at a second switching frequency when the AC power output from the inverter is negative when the regenerative operation is performed at a second switching frequency lower than the first switching frequency. The first phase arm switching element and the first lower arm switching element operate at a first switching frequency.

On the other hand, when the alternating current power output from the inverter is positive, and the alternating current power output from the inverter is negative, the first phase arm switching element and the first lower arm switching element operate at a first switching frequency. The two phase arm switching element and the second lower arm switching element operate at a second switching frequency lower than the first switching frequency.

On the other hand, when the regenerative AC power output from the inverter is positive, the first phase arm switching element and the first lower arm switching element operate at the first switching frequency, and the second phase arm switching element and the second lower arm switching element are The first and second phase arm switching elements and the first and second lower arm switching elements may operate at a second switching frequency lower than the first switching frequency, and when the regenerative AC power outputted from the inverter is negative, Operate at a frequency.

According to an embodiment of the present invention, a power converter and a photovoltaic module having the same include a first and a second upper arm switching element and a first and a second lower arm switching element, and convert the DC power from the converter into an AC power source. An inverter to be converted and a current detector connected between the first lower arm switching element in the inverter and the ground, wherein the first and second upper arm switching elements and the first and second lower arm switching elements in the inverter include gallium nitride. And a transistor, and when regenerating, when the AC power output from the inverter is negative, the first lower arm switching element and the second phase arm switching element are turned on. Thereby, high speed switching is possible, the reverse current at the time of switching is reduced, and current detection at the time of regeneration is attained. Therefore, the inverter and the power converter can be miniaturized.

On the other hand, when the regenerative AC power output from the inverter is positive, the first phase arm switching element and the first lower arm switching element operate at the first switching frequency, and the second phase arm switching element and the second lower arm switching element are The first phase arm switching element and the first lower arm switching element operate at a second switching frequency when the AC power output from the inverter is negative when the regenerative operation is performed at a second switching frequency lower than the first switching frequency. The first phase arm switching element and the first lower arm switching element operate at a first switching frequency. Thereby, high speed switching is possible, the reverse current at the time of switching is reduced, and current detection at the time of regeneration is attained. Therefore, the inverter and the power converter can be miniaturized.

On the other hand, when the alternating current power output from the inverter is positive, and the alternating current power output from the inverter is negative, the first phase arm switching element and the first lower arm switching element operate at a first switching frequency. The two phase arm switching element and the second lower arm switching element operate at a second switching frequency lower than the first switching frequency. Thereby, high speed switching is possible, the reverse current at the time of switching is reduced, and current detection at the time of regeneration is attained. Therefore, the inverter and the power converter can be miniaturized.

On the other hand, when the regenerative AC power output from the inverter is positive, the first phase arm switching element and the first lower arm switching element operate at the first switching frequency, and the second phase arm switching element and the second lower arm switching element are The first and second phase arm switching elements and the first and second lower arm switching elements may operate at a second switching frequency lower than the first switching frequency, and when the regenerative AC power outputted from the inverter is negative, Operate at a frequency. Thereby, high speed switching is possible, the reverse current at the time of switching is reduced, and current detection at the time of regeneration is attained. Therefore, the inverter and the power converter can be miniaturized.

On the other hand, the power converter and the solar module having the same according to another embodiment of the present invention, the first and second phase arm switching element and the first and second lower arm switching element, and the direct current power from the converter And a current detector connected between the first lower arm switching element in the inverter and the ground, wherein the first and second phase arm switching elements and the first lower arm switching element in the inverter include a gallium nitride transistor. The second lower arm switching element includes a silicon field effect transistor, and when regenerating, when the AC power output from the inverter is negative, the first lower arm switching element and the second phase arm switching element are turned on. Thereby, high speed switching is possible, the reverse current at the time of switching is reduced, and current detection at the time of regeneration is attained. Therefore, the inverter and the power converter can be miniaturized.

On the other hand, when the regenerative AC power output from the inverter is positive, the first phase arm switching element and the first lower arm switching element operate at the first switching frequency, and the second phase arm switching element and the second lower arm switching element are The first phase arm switching element and the first lower arm switching element operate at a second switching frequency when the AC power output from the inverter is negative when the regenerative operation is performed at a second switching frequency lower than the first switching frequency. The first phase arm switching element and the first lower arm switching element operate at a first switching frequency. Thereby, high speed switching is possible, the reverse current at the time of switching is reduced, and current detection at the time of regeneration is attained. Therefore, the inverter and the power converter can be miniaturized.

On the other hand, when the alternating current power output from the inverter is positive, and the alternating current power output from the inverter is negative, the first phase arm switching element and the first lower arm switching element operate at a first switching frequency. The two phase arm switching element and the second lower arm switching element operate at a second switching frequency lower than the first switching frequency. Thereby, high speed switching is possible, the reverse current at the time of switching is reduced, and current detection at the time of regeneration is attained. Therefore, the inverter and the power converter can be miniaturized.

On the other hand, when the regenerative AC power output from the inverter is positive, the first phase arm switching element and the first lower arm switching element operate at the first switching frequency, and the second phase arm switching element and the second lower arm switching element are The first and second phase arm switching elements and the first and second lower arm switching elements may operate at a second switching frequency lower than the first switching frequency, and when the regenerative AC power outputted from the inverter is negative, Operate at a frequency. Thereby, high speed switching is possible, the reverse current at the time of switching is reduced, and current detection at the time of regeneration is attained. Therefore, the inverter and the power converter can be miniaturized.

1A is a diagram illustrating an example of a solar system including a solar module according to an embodiment of the present invention.
1B is a view showing another example of a solar 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.
4 is a circuit diagram illustrating a junction box inside the solar module of FIG. 2.
5A is a diagram illustrating peak current mode control and average current mode control of an inverter.
5B and 5C are diagrams showing the current detection method.
6A to 6B are diagrams showing an example of a conventional inverter circuit.
6C to 6F are views showing another example of the conventional inverter circuit.
7A to 7D are diagrams showing still another example of the conventional inverter circuit.
7E to 7H are diagrams showing still another example of the conventional inverter circuit.
8A to 8D are diagrams showing still another example of the conventional inverter circuit.
9A to 9D are diagrams showing an example of an inverter circuit according to an embodiment of the present invention.
10A to 10D are diagrams showing another example of the inverter circuit according to the embodiment of the present invention.
11A to 11D are diagrams showing still another example of the inverter circuit according to the embodiment of the present invention.
12 is an example of a circuit diagram of a power conversion device in a solar module according to an embodiment of the present invention.
13 is another example of a circuit diagram of a power converter in a solar module according to an embodiment of the present invention.
14A to 14E are views referred to for describing operation of FIGS. 12 to 13.

In this specification, a method of reducing the ripple of an input current input to a converter in a solar module is proposed.

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

The suffixes "module" and "unit" for components used in the following description are merely given in consideration of ease of preparation of the present specification, and do not impart any particular meaning or role by themselves. Therefore, the "module" and "unit" may be used interchangeably.

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

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

The solar module 50 may include a junction box 200 including a solar cell module 100 and a power converter (500 in FIG. 4) that converts and outputs DC power in the solar cell module. have.

In the drawing, the junction box 200 is attached to the back of the solar cell module 100, but is not limited thereto. The junction box 200 may be provided separately from the solar cell module 100.

Meanwhile, a cable oln for supplying AC power output from the junction box 200 to the grid may be electrically connected to an output terminal of the junction box 200.

The gateway 80 may be located between the junction box 200 and the grid 90.

On the other hand, the gateway 80 may detect an alternating current io and an alternating voltage vo output from the photovoltaic module 50 flowing through the cable oln.

Meanwhile, the gateway 80 may output a power factor adjustment signal for power factor adjustment based on a phase difference between the AC current io and the AC voltage vo output from the solar module 50.

To this end, the gateway 80 and the solar module 50 may perform power line communication (PLC communication) or the like using the cable 323.

On the other hand, the power converter (500 in FIG. 4) in the photovoltaic module 50 can convert the DC power output from the solar cell module 100 into an AC power, and output it.

To this end, a converter (530 of FIG. 4) and an inverter (540 of FIG. 4) may be provided in the power converter (500 of FIG. 4) in the solar module 50.

On the other hand, the present invention provides a method capable of high-speed switching, the reverse current at the time of switching is reduced, the current detection at the time of regeneration. This will be described below with reference to FIG. 9A.

Next, Figure 1b is a view showing another example of a solar system including a solar module according to an embodiment of the present invention.

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

Unlike the photovoltaic system 10a of FIG. 1A, the photovoltaic system 10b of FIG. 1B differs in that a plurality of photovoltaic modules 50a, 50b,..., 50n are connected in parallel with each other.

Each of the plurality of photovoltaic modules 50a, 50b, ..., 50n is a circuit that converts and outputs DC power in each of the photovoltaic modules 100a, 100b, ..., 100n and the photovoltaic module. Junction boxes 200a, 200b,..., 200n including the elements may be provided.

In the drawing, although each junction box 200a, 200b, ..., 200n is attached to the back surface of each solar cell module 100a, 100b, ..., 100n, it is not limited to this. Each junction box 200a, 200b, ..., 200n may be provided separately from each solar cell module 100a, 100b, ..., 100n.

On the other hand, the cables 31a, 31b, ..., oln for supplying the AC power output from each junction box 200a, 200b, ..., 200n to a grid are each junction box 200a, 200b,. .., 200n) can be electrically connected to the output terminal.

On the other hand, the inverter 540 in each power converter 500 in the plurality of photovoltaic modules 50a, 50b, ..., 50n of FIG. 1B can perform high-speed switching, and the reverse current at the time of switching is reduced. It is preferable that the current can be detected during regeneration. This will be described below with reference to FIG. 9A.

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

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

The junction box 200 may include at least one bypass diode, which is bypassed in order to prevent hot spots in case of shading.

In FIG. 4 and the like, corresponding to the four solar cell strings of FIG. 2, three bypass diodes (Da, Db, and Dc of FIG. 4) are illustrated.

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

On the other hand, the solar cell module 100 may be provided with a plurality of solar cells.

In the drawing, a plurality of Taeang cells are connected in a line by a ribbon (133 in FIG. 12), and thus, a solar cell string 140 is formed. As a result, six strings 140a, 140b, 140c, 140d, 140e, and 140f are formed, and each string includes ten solar cells. On the other hand, unlike the drawings, various modifications are possible.

On the other hand, each solar cell string may be electrically connected by a bus ribbon. FIG. 2 shows that the first solar cell string 140a and the second solar cell string 140b are formed by the bus ribbons 145a, 145c, and 145e disposed under the solar cell module 100, respectively. 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.

In addition, in FIG. 2, the 2nd solar cell string 140b and the 3rd solar cell string 140c are respectively comprised by the bus ribbon 145b and 145d arrange | positioned on the upper part of the solar cell module 100, The 4th aspect It illustrates 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), respectively. 4 conductive lines (not shown) are bypass diodes in the junction box 200 disposed on the rear surface of the solar cell module 100 through openings formed in the solar cell module 100 (Da, Db, and Dc of FIG. 4). ) Can be connected.

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

4 is a circuit diagram illustrating a junction box inside the solar module of FIG. 2.

Referring to the drawing, the junction box 200 may output the converted power by converting the DC power from the solar cell module 100.

In particular, in connection with the present invention, the junction box 200 may be provided with a power converter (500 in FIG. 4) for outputting AC power.

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

In addition, the junction box 200 may further include a bypass diode unit 510 for bypass, a capacitor unit 520 for DC power storage, and a filter unit 570 for filtering the AC power output. have.

On the other hand, 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 detector A, an input voltage detector B, a converter output current detector C, a converter output voltage detector D, an inverter output current detector E, and an inverter output voltage. The detection unit F may be further provided.

The controller 550 may control the converter 530, the inverter 540, and the communication unit 580.

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

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

On the other hand, the DC power that has passed through the bypass diode unit 510 may be input to the capacitor unit 520.

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

Meanwhile, in the drawing, the capacitor unit 520 is illustrated as having a plurality of capacitors Ca, Cb, and Cc connected in parallel to each other. Alternatively, the plurality of capacitors are connected in series or parallel mixing, or grounded in series. It is also possible to be connected to the stage. Alternatively, the capacitor unit 520 may include only one capacitor.

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

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

On the other hand, converter 530 according to an embodiment of the present invention will be described in more detail with reference to FIG.

Meanwhile, the switching elements in the converter 530 may be turned on / off based on the converter switching control signal from the controller 550. Thereby, the level-converted DC power supply can be output.

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

In the figure, a full-bridge inverter is illustrated. That is, the upper and lower arm switching elements S1 and S3 and the lower arm switching elements S2 and S4 respectively connected in series are paired, and a total of two pairs of upper and lower arm switching elements are parallel to each other (S1, S2, S3 and S4). Leads to. Diodes may be connected in anti-parallel to each switching element Q1 to Q4.

The switching elements Q1 to Q4 in the inverter 540 may be turned on / off based on the inverter switching control signal from the controller 550. As a result, an AC power supply having a predetermined frequency can be output. Preferably, it is preferable to have the same frequency (approximately 60 Hz or 50 Hz) as the alternating frequency of the grid.

Meanwhile, the capacitor C may be disposed between the converter 530 and the inverter 540.

The capacitor C may store the level converted DC power of the converter 530. On the other hand, both ends of the capacitor (C) may be referred to as the dc terminal, accordingly, the capacitor (C) may be called a dc terminal capacitor.

Meanwhile, the input current detector A may detect the input current ic1 supplied from the solar cell module 100 to the capacitor unit 520.

Meanwhile, the input voltage detector B may detect the input voltage Vc1 supplied from the solar cell module 100 to the capacitor unit 520. Here, the input voltage Vc1 may be the same as the voltage stored across the capacitor unit 520.

The sensed input current ic1 and the input voltage vc1 may be input to the controller 550.

Meanwhile, the converter output current detector C detects the output current ic2 output from the converter 530, that is, the dc terminal current, and the converter output voltage detector D outputs the output voltage output from the converter 530. (vc2), i.e., the dc terminal voltage. The sensed output current ic2 and output voltage vc2 may be input to the controller 550.

The inverter output current detector E detects a current ic3 output from the inverter 540, and the inverter output voltage detector F detects a voltage vc3 output from the inverter 540. The detected current ic3 and voltage vc3 are input to the control unit 550.

The controller 550 may output a control signal for controlling the switching elements of the converter 530. In particular, the controller 550 may be configured to at least one of the detected 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 the switching elements in the converter 530 may be output.

The controller 550 may output an inverter control signal for controlling the respective switching elements Q1 to Q4 of the inverter 540. In particular, the controller 550 may be configured to at least one of the detected input current ic1, input voltage vc1, output current ic2, output voltage vc2, output current ic3, or output voltage vc3. On the basis of this, the turn-on timing signals of the respective switching elements Q1 to Q4 of the inverter 540 may be output.

The controller 550 may control the converter 530 to calculate a maximum power point for the solar cell module 100 and to output a DC power corresponding to the maximum power.

On the other hand, the communication unit 580 may communicate with the gateway 80.

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

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

Meanwhile, the filter unit 570 may be disposed at an output terminal of the inverter 540.

The filter unit 570 includes a plurality of passive elements, and based on at least some of the plurality of passive elements, the phase difference between the alternating current io and the alternating voltage vo output from the inverter 540. Can be adjusted.

On the other hand, as a control method of the inverter 540, there are voltage mode control and current mode control. Dual current mode control includes Peak Current Mode Control (PCMC) and Average Current Mode Control (ACMC).

5A is a diagram illustrating peak current mode control and average current mode control of an inverter.

On the other hand, the peak current mode control (PCMC) has excellent characteristics when the response to the load change is fast. Accordingly, peak current mode control (PCMC) is suitable for inverter 540 in photovoltaic module 50.

According to Peak Current Mode Control (PCMC), in step 1 the switch is turned on and the actual inductor current rises (see * 1), in step 2 the actual inductor current matches the reference current and the switch stops (see * 2). In Step 3, Step 1 is again performed after a certain time has elapsed from Step 1 (see * 3).

5B and 5C are diagrams showing the current detection method.

First, referring to FIG. 5B, a current detector may be connected to a plurality of phase arm switching elements of the inverter 540 and a phase arm switching element among the lower arm switching elements.

That is, the current detector may be connected between the phase arm switching element of the inverter 540 and the inductor in the filter unit 570.

However, such a current detector has a maximum frequency band of detectable current of about 4 MHz and is relatively low.

Meanwhile, referring to FIG. 5C, a current detector may be connected to the plurality of upper arm switching elements and the lower arm switching element among the lower arm switching elements.

That is, the current detector may be connected between the lower arm switching element of the inverter 540 and the ground GND.

In this case, in the case of current detection, there is an advantage that the pure resistor and the high speed operational amplifier can detect up to a high frequency band of 100 MHz.

Therefore, when the peak current mode control PCMC is applied to the inverter 540, it is preferable that the current detector is connected between the lower arm switching element of the inverter 540 and the ground GND as shown in FIG. 5C.

6A to 6B are diagrams showing an example of a conventional inverter circuit.

Referring to the drawings, the inverter of FIGS. 6A to 6B includes a plurality of phase arm switching elements Q1 and Q3 and lower arm switching elements Q2 and Q4, and a plurality of phase arm switching elements Q1 and Q3 and lower arm switching. It illustrates that elements Q2 and Q4 are all silicon field effect transistors (FET).

6A to 6B illustrate that a current detector is connected between the lower arm switching element of the inverter and the ground GND.

6A illustrates a circuit operation according to a current path when the output AC power is positive, and FIG. 6B illustrates a circuit operation according to a current path when the AC power output is negative.

In the case of Fig. 6A, current detection is required, while in the case of Fig. 6A, current detection is not required.

In addition, in the case of FIG. 6B (a), current detection is required, while in the case of FIG. 6B (b), current detection is not necessary.

Meanwhile, according to the inverter of FIGS. 6A to 6B, in the case of FIG. 6A, reverse current may flow through the lower arm switching element Q2, and accordingly, reverse recovery quantity of charge Electric charge (Qrr) causes heat generation in the silicon field effect transistor (FET). This occurs repeatedly in the case of Fig. 6A (a).

Therefore, when using a silicon field effect transistor (FET), maintaining the switching frequency at 100 kHz is dangerous due to heat generation.

On the other hand, in the trend of miniaturization of inverters, etc., according to the inverters of FIGS. 6A to 6B, due to heat generation, there is a disadvantage in that miniaturization is difficult.

6C to 6F are views showing another example of the conventional inverter circuit.

Referring to the drawings, the inverter of FIGS. 6C to 6F includes a plurality of phase arm switching elements Q1 and Q3 and lower arm switching elements Q2 and Q4, and a plurality of phase arm switching elements Q1 and Q3 and lower arm switching. Among the elements Q2 and Q4, the first phase arm switching element Q1 and the first lower arm switching element Q2 are gallium nitride (GaN) transistors, and the second phase arm switching element Q3 and the second lower arm switching element Q4 exemplifies a silicon field effect transistor (FET).

6C to 6F illustrate that a current detector is connected between the lower arm switching element Q2 and the ground GND of the inverter.

FIG. 6C illustrates a circuit operation according to a current path when the AC power output during generation is positive, and FIG. 6D illustrates a circuit operation according to a current path when AC power output during generation is negative. do.

FIG. 6E illustrates a circuit operation according to a current path when the AC power output at the time of discharge is positive, and FIG. 6F illustrates a circuit operation according to a current path when the AC power output at the time of regeneration is negative. do.

On the other hand, in the case of (a) of Figs. 6C to 6F, current detection is required, but in the case of Figs. 6C to 6F, the current detection is not necessary.

On the other hand, in the gallium nitride (GaN) transistor, the reverse recovery amount Qrr of the charge is theoretically zero.

Thus, the reverse current appears to be quite small, on the order of 1%. Therefore, the problem as shown in Figs. 6A to 6B does not occur.

On the other hand, in the case of Figure 6g, the current detection unit can detect the current, in the case of Figure 6f, there is a disadvantage that the current detection is impossible.

7A to 7D are diagrams showing still another example of the conventional inverter circuit.

Referring to the drawings, the inverter of FIGS. 7A to 7D includes a plurality of phase arm switching elements Q1 and Q3 and lower arm switching elements Q2 and Q4, and a plurality of phase arm switching elements Q1 and Q3 and lower arm switching. Among the elements Q2 and Q4, the lower arm switching elements Q2 and Q4 are gallium nitride (GaN) transistors, and the phase arm switching elements Q1 and Q3 are silicon field effect transistors (FETs).

7A to 7D illustrate that a current detector is connected between the lower arm switching element of the inverter and the ground GND.

FIG. 7A illustrates a circuit operation according to a current path when the AC power output during generation is positive, and FIG. 7B illustrates a circuit operation according to a current path when AC power output during generation is negative. do.

FIG. 7C illustrates a circuit operation according to a current path when the AC power output at the time of discharge is positive, and FIG. 7D illustrates a circuit operation according to a current path when the AC power output at the time of regeneration is negative. do.

On the other hand, in the case of FIGS. 7A to 7D, current detection is required, but in the case of FIGS. 7A to 7D, current detection is not necessary.

On the other hand, in the gallium nitride (GaN) transistor, the reverse recovery amount Qrr of the charge is theoretically zero.

Therefore, in the case of FIGS. 7A and 7D, the reverse current flowing to the lower arm switching element Q2 is hardly issued.

However, in the case of FIGS. 7B and 7C (a), the reverse current flowing to the phase arm switching element Q1 is generated significantly.

7E to 7H are diagrams showing still another example of the conventional inverter circuit.

Referring to the drawings, the inverter of FIGS. 7E to 7H includes a plurality of phase arm switching elements Q1 and Q3 and lower arm switching elements Q2 and Q4, and a plurality of phase arm switching elements Q1 and Q3 and lower arm switching. Among the elements Q2 and Q4, the phase arm switching elements Q1 and Q3 are gallium nitride (GaN) transistors, and the lower arm switching elements Q2 and Q4 are silicon field effect transistors (FETs).

7E to 7H illustrate that a current detector is connected between the lower arm switching element Q2 and the ground GND of the inverter.

FIG. 7E illustrates a circuit operation according to a current path when the AC power output during generation is positive, and FIG. 7F illustrates a circuit operation according to a current path when AC power output during generation is negative. do.

FIG. 7G illustrates a circuit operation according to a current path when the AC power output at the time of discharge is positive, and FIG. 7H illustrates a circuit operation according to a current path when the AC power output at the time of regeneration is negative. do.

On the other hand, in the case of FIGS. 7E to 7H (a), current detection is necessary, but in case of FIGS. 7E to 7H (b), current detection is not necessary.

On the other hand, in the gallium nitride (GaN) transistor, the reverse recovery amount Qrr of the charge is theoretically zero.

Therefore, in the case of FIGS. 7F and 7G (a), almost no reverse current flowing to the phase arm switching element Q1 is generated.

However, in the case of Figs. 7E and 7H (a), the reverse current flowing to the lower arm switching element Q2 is generated significantly.

8A to 8D are diagrams showing still another example of the conventional inverter circuit.

Referring to the drawings, the inverter of FIGS. 8A to 8D includes a plurality of phase arm switching elements Q1 and Q3 and lower arm switching elements Q2 and Q4, and a plurality of phase arm switching elements Q1 and Q3 and lower arm switching. It illustrates that both the elements Q2 and Q4 are gallium nitride (GaN) transistors.

8A to 8D illustrate that a current detector is connected between the lower arm switching element Q2 and the ground GND of the inverter.

FIG. 8A illustrates a circuit operation according to a current path when the AC power output during generation is positive, and FIG. 8B illustrates a circuit operation according to a current path when AC power output during generation is negative. do.

FIG. 8C illustrates a circuit operation according to a current path when the AC power output at the time of discharge is positive polarity, and FIG. 8D illustrates a circuit operation according to a current path when the AC power output at the time of regeneration is negative polarity. do.

On the other hand, in the case of FIGS. 8A to 8D (a), current detection is required, but in the case of FIGS. 8A to 8D (b), current detection is not necessary.

On the other hand, in the gallium nitride (GaN) transistor, the reverse recovery amount Qrr of the charge is theoretically zero.

Therefore, in the case of FIGS. 8A to 8D, almost no reverse current flowing to the upper arm or the lower arm switching element is generated.

On the other hand, in the case of Figure 8c, the current detection unit can detect the current, in the case of Figure 8d, there is a disadvantage that the current detection is impossible.

9A to 9D are diagrams showing an example of an inverter circuit according to an embodiment of the present invention.

Referring to the drawings, the inverter of FIGS. 9A to 9D includes a plurality of phase arm switching elements Q1 and Q3 and lower arm switching elements Q2 and Q4, and a plurality of phase arm switching elements Q1 and Q3 and lower arm switching. It illustrates that both the elements Q2 and Q4 are gallium nitride (GaN) transistors.

9A to 9D illustrate that a current detector is connected between the lower arm switching element Q2 and the ground GND of the inverter.

9A illustrates a circuit operation according to a current path when the AC power output during generation is positive, and FIG. 9B illustrates a circuit operation according to a current path when AC power output during generation is negative. do.

FIG. 9C illustrates a circuit operation according to a current path when the AC power output at the time of discharge is positive, and FIG. 9D illustrates a circuit operation according to a current path when the AC power output at the time of regeneration is negative. do.

On the other hand, in the case of FIGS. 9A to 9D (a), current detection is required, but in the case of FIGS. 9A to 9D (b), current detection is not necessary.

Meanwhile, the switching frequencies of the first upper arm switching element Q1 and the first lower arm switching element Q2 among the plurality of upper arm switching elements Q1 and Q3 and the lower arm switching elements Q2 and Q4 and the second upper arm switching element ( The switching frequency of Q3) and the second lower arm switching element Q4 may be different.

For example, when the AC power output during the power generation of FIGS. 9A and 9B and the discharge of FIG. 9C is positive, the plurality of phase arm switching elements Q1 and Q3 and the lower arm switching elements Q2 and Q4 are used. The first upper arm switching element Q1 and the first lower arm switching element Q2 operate at the first switching frequency, and the second upper arm switching element Q3 and the second lower arm switching element Q4 are the first switching. Operate at a second switching frequency lower than the frequency.

Here, the first switching frequency may be 100KHz and the second switching frequency may be 50KHz.

On the other hand, when the AC power output when the regenerative power of FIG. 9D is negative, the first phase arm switching element Q1 and the first lower arm switching element among the plurality of phase arm switching elements Q1 and Q3 and the lower arm switching elements Q2 and Q4 are provided. Q2 may operate at the second switching frequency, and the second upper arm switching element Q3 and the second lower arm switching element Q4 may operate at the first switching frequency.

On the other hand, in the case of Figure 9c, the current detection unit can detect the current, in the case of Figure 9d, there is an advantage that the current can be detected.

That is, when the alternating current power output when the regenerative power of FIG. 9D is negative, the current is changed by the first lower arm switching element Q2, the first inductor, the grid, the second inductor, and the second phase arm switching in the resistance element of the current detector. Flow through element Q3.

That is, when the AC power output at the time of regeneration of FIG. 9D is negative, the controller 550 controls the first lower arm switching element Q2 and the second upper arm switching element Q3 to be turned on. This enables current detection.

10A to 10D are diagrams showing another example of the inverter circuit according to the embodiment of the present invention.

Referring to the drawings, the inverters of FIGS. 10A to 10D include a plurality of phase arm switching elements Q1 and Q3 and lower arm switching elements Q2 and Q4, and a plurality of phase arm switching elements Q1 and Q3 and a first phase. The lower arm switching element Q2 is a gallium nitride (GaN) transistor, and the second lower arm switching element Q4 is a silicon field effect transistor (FET).

10A to 10D illustrate that a current detector is connected between the lower arm switching element Q2 and the ground GND of the inverter.

10A illustrates a circuit operation according to a current path when the AC power output during generation is positive, and FIG. 10B illustrates a circuit operation according to a current path when AC power output during generation is negative. do.

FIG. 10C illustrates a circuit operation according to a current path when the AC power output at the time of discharge is positive, and FIG. 10D illustrates a circuit operation according to a current path when the AC power output at the time of regeneration is negative. do.

On the other hand, in the case of Figs. 10A to 10D, current detection is required, but in the case of Figs. 10A to 10D, current detection is not required.

Meanwhile, the switching frequencies of the first upper arm switching element Q1 and the first lower arm switching element Q2 among the plurality of upper arm switching elements Q1 and Q3 and the lower arm switching elements Q2 and Q4 and the second upper arm switching element ( The switching frequency of Q3) and the second lower arm switching element Q4 may be different.

For example, when the AC power output during the power generation of FIGS. 10A and 10B and the regeneration of FIG. 10C is positive, the plurality of phase arm switching elements Q1 and Q3 and the lower arm switching elements Q2 and Q4 are provided. The first upper arm switching element Q1 and the first lower arm switching element Q2 operate at the first switching frequency, and the second upper arm switching element Q3 and the second lower arm switching element Q4 are the first switching. Operate at a second switching frequency lower than the frequency.

Here, the first switching frequency may be 100KHz and the second switching frequency may be 50KHz.

On the other hand, when the AC power output during the regeneration of FIG. 10D has a negative polarity, the first phase arm switching element Q1 and the first lower arm switching element among the plurality of phase arm switching elements Q1 and Q3 and the lower arm switching elements Q2 and Q4 may be used. Q2 may operate at the second switching frequency, and the second upper arm switching element Q3 and the second lower arm switching element Q4 may operate at the first switching frequency.

On the other hand, in the case of Figure 10c, the current detection unit can detect the current, in the case of Figure 10d, there is an advantage that the current can be detected.

That is, when the alternating current power output when the regenerative power of FIG. 10D is negative, the current is changed by the first lower arm switching element Q2, the first inductor, the grid, the second inductor, and the second phase arm switching in the resistance element of the current detection unit. Flow through element Q3.

That is, when the AC power output at the time of regeneration of FIG. 10D is negative, the controller 550 controls the first lower arm switching element Q2 and the second upper arm switching element Q3 to be turned on. This enables current detection.

11A to 11D are diagrams showing still another example of the inverter circuit according to the embodiment of the present invention.

11A to 11D are similar to the inverter circuits of FIGS. 10A to 10D, the upper arm switching elements Q1 and Q3 and the first lower arm switching element Q2 are gallium nitride (GaN) transistors. The lower arm switching element Q4 exemplifies a silicon field effect transistor (FET).

For example, when the AC power output during the power generation of FIGS. 11A and 11B and the regeneration of FIG. 10C is positive, the plurality of phase arm switching elements Q1 and Q3 and the lower arm switching elements Q2 and Q4 are provided. The first upper arm switching element Q1 and the first lower arm switching element Q2 operate at the first switching frequency, and the second upper arm switching element Q3 and the second lower arm switching element Q4 are the first switching. Operate at a second switching frequency lower than the frequency.

Here, the first switching frequency may be 100KHz and the second switching frequency may be 50KHz.

On the other hand, when the AC power output at the time of regenerative of FIG. Q2 may operate at the first switching frequency, and the second upper arm switching element Q3 and the second lower arm switching element Q4 may operate at the first switching frequency.

That is, when the AC power output during the regeneration of FIG. 11D is negative, all of the inverter switching elements Q1 to Q4 may operate at a constant switching frequency.

On the other hand, in the case of Figure 11c, the current detection unit can detect the current, also in the case of Figure 11d, there is an advantage that the current can be detected.

That is, when the alternating current power output in the regenerative operation of FIG. 11D is negative, the current is changed by the first lower arm switching element Q2, the first inductor, the grid, the second inductor, and the second phase arm switching in the resistance element of the current detector. Flow through element Q3.

That is, when the AC power output at the time of regeneration of FIG. 11D is negative, the controller 550 controls the first lower arm switching element Q2 and the second upper arm switching element Q3 to be turned on. This enables current detection.

12 is an example of a circuit diagram of a power conversion device in a solar module according to an embodiment of the present invention.

Referring to the drawing, the power converter 1200 may include a converter 530 and an inverter module INVM.

The inverter module INVM includes a filter unit 570 including an inverter 540, a current detector configured to include resistors R1 and R2 and amplifiers OP1 and Op2, and first and second inductors L1 and L2. And a controller 550.

On the other hand, the inverter module INVM of FIG. 12 illustrates that each of the switching elements Q1 to Q4 in the inverter 540 is a gallium nitride (GaN) transistor, as shown in FIGS. 9A to 9D. .

The control unit 550 is a selector 1210 for detecting the signals detected by the first and second resistors R1 and R2 of the current detection unit and amplified by the amplifiers OP1 and OP2, respectively, and comparing the comparator ( 1215, a control signal generator 1220 for generating a pulse width control signal.

The control signal generator 1220 may generate and output a switching control signal input to the gate terminals of the switching elements Q1 to Q4 in the inverter 540.

13 is another example of a circuit diagram of a power converter in a solar module according to an embodiment of the present invention.

Referring to the drawing, the power converter 1300 may include a converter 530 and an inverter module INVM.

The inverter module INVM includes a filter unit 570 including an inverter 540, a current detector configured to include resistors R1 and R2 and amplifiers OP1 and Op2, and first and second inductors L1 and L2. And a controller 550.

Meanwhile, as shown in FIGS. 10A to 11D, the inverter module INVM of FIG. 13 may include the plurality of phase arm switching elements Q1 and Q3 and the first phase among the switching elements Q1 to Q4 in the inverter 540. The lower arm switching element Q2 is a gallium nitride (GaN) transistor, and the second lower arm switching element Q4 is a silicon field effect transistor (FET).

The control unit 550 is a selector 1210 for detecting the signals detected by the first and second resistors R1 and R2 of the current detection unit and amplified by the amplifiers OP1 and OP2, respectively, and comparing the comparator ( 1215, a control signal generator 1220 for generating a pulse width control signal.

The control signal generator 1220 may generate and output a switching control signal input to the gate terminals of the switching elements Q1 to Q4 in the inverter 540.

14A to 14E are views referred to for describing operation of FIGS. 12 to 13.

First, FIG. 14A is a diagram for explaining the operation of the switching elements Q1 to Q4 in the inverter when the AC power output during generation is positive.

Referring to the drawings, when the polarity of the reference sine wave is positive polarity, the second lower arm switching element Q4 is turned on, and when the polarity of the reference sine wave is negative polarity, the second phase arm switching element (Q3) is turned on.

At this time, the second upper arm switching element Q3 and the second lower arm switching element Q4 perform a switching operation at a second switching frequency, that is, 50 KHz, and the first upper arm switching element Q1 and the first lower arm switching. The element Q2 can perform a switching operation at a first switching frequency, that is, 100 KHz.

Next, FIG. 14B is a diagram for explaining the operation of the switching elements Q1 to Q4 in the inverter when the AC power output at the time of power generation is negative.

Referring to the drawings, when the polarity of the reference sine wave is positive polarity, the second phase arm switching element Q3 is turned on, and when the polarity of the reference sine wave is negative polarity, the second lower arm switching element (Q4) is turned on.

At this time, the second upper arm switching element Q3 and the second lower arm switching element Q4 perform a switching operation at a second switching frequency, that is, 50 KHz, and the first upper arm switching element Q1 and the first lower arm switching. The element Q2 can perform a switching operation at a first switching frequency, that is, 100 KHz.

Next, FIG. 14C is a diagram for explaining the operation of the switching elements Q1 to Q4 in the inverter when the AC power output at the time of discharge is positive.

Referring to the drawings, when the polarity of the reference sine wave is positive polarity, the second lower arm switching element Q4 is turned on, and when the polarity of the reference sine wave is negative polarity, the second phase arm switching element (Q3) is turned on.

At this time, the second upper arm switching element Q3 and the second lower arm switching element Q4 perform a switching operation at a second switching frequency, that is, 50 KHz, and the first upper arm switching element Q1 and the first lower arm switching. The element Q2 can perform a switching operation at a first switching frequency, that is, 100 KHz.

Next, FIG. 14D is a diagram for explaining the operation of the switching elements Q1 to Q4 in the inverter when the AC power output at the time of regeneration is negative.

Referring to the drawings, when the polarity of the reference sine wave is positive, the first phase arm switching element Q1 is turned on, and when the polarity of the reference sine wave is negative, the first lower arm switching element (Q2) is turned on.

At this time, the first upper arm switching element Q1 and the first lower arm switching element Q2 perform a switching operation at a second switching frequency, that is, 50 KHz, and the second upper arm switching element Q3 and the second lower arm switching The element Q4 can perform a switching operation at a first switching frequency, that is, 100 KHz.

FIG. 14E is a diagram for explaining the operation of the switching elements Q1 to Q4 in the inverter when the AC power output at the time of regeneration is negative.

Referring to the drawings, when the polarity of the reference sine wave is positive, the first phase arm switching element Q1 and the second lower arm switching element Q4 are turned on, turned off after being turned on, and a reference sine wave. When the polarity of the wave is negative, the first phase arm switching element Q1 and the second lower arm switching element Q4 are turned on and then turned off.

On the other hand, the first lower arm switching element Q2 operates complementarily with the first upper arm switching element Q1, and the second upper arm switching element Q3 operates complementarily with the second lower arm switching element Q4. do.

At this time, the first upper arm switching element Q1, the first lower arm switching element Q2, the second upper arm switching element Q3, and the second lower arm switching element Q4 are switched at a first switching frequency, that is, 100 KHz. can do.

The power converter and the solar module including the same according to the present invention are not limited to the configuration and method of the embodiments described as described above, but the embodiments may be modified in various ways. All or part may be selectively combined.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims (9)

A converter for converting a level of DC power input from the solar cell module;
An inverter having first and second upper arm switching elements and first and second lower arm switching elements, the inverter converting a direct current power source from the converter into an alternating current power source;
And a current detector connected between the first lower arm switching element and the ground in the inverter.
In the inverter, the first and second phase arm switching elements and the first and second lower arm switching elements include gallium nitride transistors,
And a first lower arm switching element and a second phase arm switching element are turned on when the AC power output from the inverter is negative during regeneration. The method of claim 1,
When the regenerative AC power output from the inverter is positive, the first upper arm switching element and the first lower arm switching element operate at a first switching frequency, and the second upper arm switching element and the second lower arm are operated. The switching device operates at a second switching frequency lower than the first switching frequency,
When the regenerative AC power output from the inverter is negative, the first upper arm switching element and the first lower arm switching element operate at the second switching frequency, and the first upper arm switching element and the first upper arm switching element are operated. The lower arm switching element operates at the first switching frequency. The method of claim 1,
During power generation, when the AC power output from the inverter is positive, and when the AC power output from the inverter is negative, the first phase arm switching element and the first lower arm switching element operate at a first switching frequency. And the second upper arm switching element and the second lower arm switching element operate at a second switching frequency lower than the first switching frequency. The method of claim 1,
When the regenerative AC power output from the inverter is positive, the first upper arm switching element and the first lower arm switching element operate at a first switching frequency, and the second upper arm switching element and the second lower arm are operated. The switching device operates at a second switching frequency lower than the first switching frequency,
When the regenerative AC power output from the inverter is negative, the first and second phase arm switching elements and the first and second lower arm switching elements operate at the first switching frequency. Inverter. A converter for converting a level of DC power input from the solar cell module;
An inverter having first and second upper arm switching elements and first and second lower arm switching elements, the inverter converting a direct current power source from the converter into an alternating current power source;
And a current detector connected between the first lower arm switching element and the ground in the inverter.
In the inverter, the first and second phase arm switching elements and the first lower arm switching element comprise gallium nitride transistors, and the second lower arm switching element comprises silicon field effect transistors,
And a first lower arm switching element and a second phase arm switching element are turned on when the AC power output from the inverter is negative during regeneration. The method of claim 5,
When the regenerative AC power output from the inverter is positive, the first upper arm switching element and the first lower arm switching element operate at a first switching frequency, and the second upper arm switching element and the second lower arm are operated. The switching device operates at a second switching frequency lower than the first switching frequency,
When the regenerative AC power output from the inverter is negative, the first upper arm switching element and the first lower arm switching element operate at the second switching frequency, and the first upper arm switching element and the first upper arm switching element are operated. The lower arm switching element operates at the first switching frequency. The method of claim 5,
During power generation, when the AC power output from the inverter is positive, and when the AC power output from the inverter is negative, the first phase arm switching element and the first lower arm switching element operate at a first switching frequency. And the second upper arm switching element and the second lower arm switching element operate at a second switching frequency lower than the first switching frequency. The method of claim 5,
When the regenerative AC power output from the inverter is positive, the first upper arm switching element and the first lower arm switching element operate at a first switching frequency, and the second upper arm switching element and the second lower arm are operated. The switching device operates at a second switching frequency lower than the first switching frequency,
When the regenerative AC power output from the inverter is negative, the first and second phase arm switching elements and the first and second lower arm switching elements operate at the first switching frequency. Inverter. A photovoltaic module comprising the power converter of any one of claims 1 to 8.

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