TWI857502B - Pv inverter - Google Patents

Abstract

A PV inverter includes a housing, at least one circuit board disposed in the housing, an current sensor disposed on the circuit board, an arc detection coil disposed on the circuit board, a self-test circuit disposed on the circuit board and at least one DC input terminal disposed on the housing and connected to the circuit board. The self-test circuit is configured to deliver a test signal for the arc detection coil to sense. The DC input terminal is configured to transmit a current to pass through the arc detection coil. The current sensor is configured to detect a magnitude of the current passing through the DC input terminal.

Description

Solar Inverter

The present disclosure relates to a solar inverter.

In a solar power system, solar panels are installed outdoors and connected to inverters, batteries and other components through cables. Under the influence of the outdoor environment, cables are easily damaged, and when cables are damaged, arcs may occur, which is very dangerous.

In view of this, one purpose of the present disclosure is to provide a solar inverter with an arc detection mechanism.

To achieve the above-mentioned purpose, according to some embodiments of the present disclosure, a solar inverter includes a housing, at least one circuit board disposed in the housing, an inductive flow sensor disposed on the circuit board, an arc detection coil disposed on the circuit board, a self-detection circuit disposed on the circuit board, and at least one DC input terminal disposed on the housing and connected to the circuit board. The self-detection circuit is configured to transmit a test signal for the arc detection coil to sense. The DC input terminal is configured to transmit a current through the arc detection coil, and the inductive flow sensor is configured to detect the magnitude of the current passing through the DC input terminal.

In summary, unlike the existing solar inverter that uses an arc detection coil wound around a ring-shaped core, the solar inverter disclosed herein integrates the arc detection coil and the self-detection circuit on a circuit board, which helps save cost and space, and can more conveniently perform arc detection and self-function detection on each solar string.

In order to make the description of the present disclosure more detailed and complete, reference may be made to the attached drawings and various embodiments described below. The elements in the drawings are not drawn to scale and are provided only for the purpose of illustrating the present disclosure. Many practical details are described below to provide a comprehensive understanding of the present disclosure. However, a person of ordinary skill in the relevant art should understand that the present disclosure can be implemented without one or more of the practical details, and therefore, these details should not be used to limit the present disclosure.

Referring to FIG. 1 , the solar power system 10 includes a plurality of solar panels 11 and a solar inverter 12. The solar inverter 12 is connected to the solar panels 11 and is configured to convert the direct current generated by the solar panels 11 into alternating current, and then output the alternating current to the power grid or power-consuming equipment. The solar inverter 12 includes an arc detection unit 13, and the arc detection unit 13 is configured to determine whether an arc fault occurs in the line between the solar inverter 12 and the solar panels 11. The solar inverter 12 also includes a DC switch 14. When the arc detection unit 13 determines that an arc fault occurs in the line between the solar inverter 12 and the solar panel 11, the DC switch 14 is configured to cut off the DC power supplied by the solar panel 11 to the solar inverter 12. The solar inverter 12 further includes a detection circuit controller 15. The detection circuit controller 15 is configured to inject a white noise or a high-frequency signal through a self-detection circuit (such as the self-detection circuit 38 of FIG. 2) to detect whether the arc detection unit 13 functions normally.

Furthermore, the solar inverter 12 can stop receiving energy from the solar panel 11 when the arc detection unit 13 determines that an arc fault occurs in the line between the solar inverter 12 and the solar panel 11 (for example, the solar inverter 12 can be shut down and stop operating, or the DC switch 14 can cut off the power supply from the solar panel 11 to the solar inverter 12). Because the solar panel 11 is a passive element, it will generate electricity when exposed to sunlight, unlike other DC power sources such as power supplies and batteries that can shut down when an abnormality is detected. Therefore, the solar power system 10 disclosed in the present invention integrates the arc detection function into the solar inverter 12, and the solar inverter 12 detects arc faults and cuts off power (stops drawing current from the solar panel 11) when an arc fault occurs to protect the solar power system 10.

Referring to FIG. 2 , the solar inverter 12 includes a housing 20 and one or more DC input terminals 25. The DC input terminals 25 are disposed on the wall of the housing 20 and connected to the solar panels 11 (omitted in FIG. 2 , see FIG. 1 ) to receive current from the solar panels 11. In some embodiments, each DC input terminal 25 is connected to a solar string, and each string may include one or more solar panels 11.

As shown in FIG. 2 , the solar inverter 12 further includes a circuit board 30, which is disposed in the housing 20 facing the DC input terminal 25 and connected to the DC input terminal 25. In this embodiment, the DC input terminal 25 is connected to the circuit board 30 via a cable 60. Specifically, the circuit board 30 has an opening 31, and one end of the cable 60 is connected to the DC input terminal 25 and extends through the circuit board 30 through the opening 31. In some embodiments, the cable 60 passes through the circuit board 30 and is connected to a connection interface (e.g., connection terminal 37) on the circuit board 30.

As shown in FIG. 2 , the solar inverter 12 further includes an electric current sensor 33 (illustratively, the specific structure is not shown) disposed on the circuit board 30, and the electric current sensor 33 is configured to detect the magnitude of the current passing through the DC input terminal 25. In other words, the circuit board 30 has the function of detecting the input current of the DC input terminal 25.

As shown in FIG. 2 , the solar inverter 12 further includes an arc detection coil 35, which is disposed on the circuit board 30 and is disposed around the opening 31 of the circuit board 30. Therefore, the DC input terminal 25 can transmit current through the arc detection coil 35 via the cable 60. In some embodiments, the arc detection coil 35 can be disposed on the surface of the circuit board 30. In other embodiments, the arc detection coil 35 can also be buried in the circuit board 30. The solar inverter 12 further includes a self-detection circuit 38, which is also disposed on the circuit board 30 and is disposed in a portion of the arc detection coil 35. The self-detection circuit 38 injects a white noise or a high frequency signal to detect whether the arc detection coil 35 can detect the white noise or the high frequency signal.

The arc detection coil 35 is, for example, a Rogowski coil. The arc detection coil 35 can be connected to the arc detection unit 13 via a signal line (see FIG. 1 ). The arc detection unit 13 can be disposed on the circuit board 30 or on other circuit boards. The arc detection unit 13 is configured to receive a signal (e.g., a voltage signal) from the arc detection coil 35, and perform signal processing and spectrum analysis on the received signal to determine whether an arc fault occurs in the string group corresponding to the DC input terminal 25. The arc detection unit 13 may include a filter, an amplifier, a digital signal processor, or other electronic components to perform filtering, amplification, Fourier analysis, and other operations to perform spectrum analysis to determine whether an arc fault occurs.

In the design of solar inverters, the current practice is to use an arc detection coil wound around a ring frame (core) to perform arc detection, and the self-detection circuit 38 is a partial section of the ring frame. However, this type of arc detection coil is relatively large, the wiring of the self-detection circuit 38 is also very messy, and the cost is also high. The solar inverter 12 disclosed in the present invention integrates the arc detection coil 35 and the self-detection circuit 38 together on the circuit board 30. This method can save the assembly space of the arc detection coil and the self-detection circuit, and the cost is also lower than that of the arc detection coil in the form of a ring frame. In addition, it is only necessary to arrange the arc detection coil 35 on the DC input terminal 25 on the circuit board 30 to perform arc detection on the corresponding string group separately.

Furthermore, the embodiment shown in FIG. 2 integrates the arc detection coil 35 and the self-detection circuit 38 on the original circuit board 30 used to match the DC input terminal 25 and having a current detection function, so that the structure of the solar inverter 12 becomes more streamlined.

It should be noted that FIG. 2 only representatively depicts one of the DC input terminals 25 connected to the circuit board 30 via the cable 60, and the arc detection coil 35 and the self-detection circuit 38 corresponding to one of the DC input terminals 25. In an actual product, each DC input terminal 25 of the solar inverter 12 may be connected to a cable 60, and a plurality of arc detection coils 35 may be disposed on the circuit board 30, each arc detection coil 35 passes through one of the DC input terminals 25 (i.e., surrounds one of the cables 60), and has a self-detection circuit 38 surrounding a portion of the arc detection coil 35.

In some embodiments, the circuit board 30 is a bus circuit board. Specifically, the circuit board 30 is configured to receive current from a plurality of DC input terminals 25 and output current through at least one output terminal (e.g., connection terminal 37) disposed on the circuit board 30, wherein the number of output terminals is less than the number of DC input terminals 25. Therefore, in these embodiments, the arc detection coil 35 and the self-detection circuit 38 are integrated into the original bus circuit board, making the structure of the solar inverter 12 more streamlined.

In some embodiments, the solar inverter 12 further includes an electromagnetic interference suppression capacitor 39 disposed on the circuit board 30. Therefore, in these embodiments, the arc detection coil 35 is integrated on the original circuit board 30 used to match the DC input terminal 25 and has the function of suppressing electromagnetic interference, so that the structure of the solar inverter 12 becomes more streamlined.

Please refer to FIG. 3. Different from the above-mentioned embodiment, in this embodiment, two or more DC input terminals 25 share one arc detection coil 35. Specifically, the circuit board 30 has a plurality of openings 31, each opening 31 is for a cable 60 to pass through, and each cable 60 is connected to a different DC input terminal 25. The arc detection coil 35 is arranged around the plurality of openings 31, so that the plurality of DC input terminals 25 transmit current through the arc detection coil 35 via the plurality of cables 60. The arc detection coil 35 can be connected to the arc detection unit via a signal line. The arc detection unit is configured to receive a signal from the arc detection coil 35 and perform signal processing and spectrum analysis on the received signal to determine whether an arc fault occurs in a string group corresponding to one of the DC input terminals 25. Some sections of the arc detection coil 35 also have a self-detection circuit 38 surrounding them to provide a self-detection function for the arc detection coil 35 and the arc detection unit.

Please refer to FIG. 4 and FIG. 5. Different from the above-mentioned embodiment in which the cable 60 is used to connect the DC input terminal 25, in this embodiment, the circuit board 30 is fixed on the DC input terminal 25. In some embodiments, the DC input terminal 25 is inserted into the opening 31 of the circuit board 30, and the end of the DC input terminal 25 is locked with a fastener 90 (e.g., a screw), thereby locking and fixing the circuit board 30 on the DC input terminal 25.

As shown in FIG. 4 and FIG. 5 , the solar inverter 12 further includes a connection terminal 37, which is disposed on the circuit board 30 and electrically connected to the DC input terminal 25 through the internal line 32 (indicated by a dotted line) of the circuit board 30. Therefore, the current will flow through the DC input terminal 25, the internal line 32 of the circuit board 30, and the connection terminal 37 in sequence. The connection terminal 37 can be externally connected to a cable 65 to transmit the current to other components of the solar inverter 12 (for example, a DC switch). The arc detection coil 35 is disposed around the DC input terminal 25 and the connection terminal 37, so that the current from the DC input terminal 25 passes through the arc detection coil 35. Some sections of the arc detection coil 35 are also provided with a self-detection circuit 38 to provide a self-detection function for the arc detection coil 35 and the arc detection unit. In some embodiments, the spiral coil formed by the arc detection coil 35 on the circuit board is a closed rectangular ring, and the self-detection circuit 38 is provided in a partial section of the closed ring. In some embodiments, the closed ring of the arc detection coil 35 can also be circular, elliptical, square or triangular, etc. In some other embodiments, the spiral coil formed by the arc detection coil 35 on the circuit board can also be an open rectangular ring, a circular ring, an elliptical ring, a square ring or a triangular ring, etc.

Please refer to FIG. 6 and FIG. 7. The difference between this embodiment and the embodiment shown in FIG. 2 is that the arc detection coil and the current flow sensor are arranged on different circuit boards. Specifically, in this embodiment, the current flow sensor is arranged on the circuit board 30 (see FIG. 2), and the solar inverter further includes a circuit board 50, and the arc detection coil 56 and its self-detection circuit 58 are arranged on the circuit board 50. The circuit board 50 has an opening 53, and the arc detection coil 56 is arranged around the opening 53. The circuit board 50 is mounted on the cable 60 connected to the DC input terminal 25. In other words, the cable 60 passes through the opening 53 of the circuit board 50, so that the arc detection coil 56 is surrounded by the cable 60. Therefore, the current from the DC input terminal 25 can pass through the arc detection coil 56 via the cable 60. A self-detection circuit 58 is provided at a portion of the arc detection coil 56 to provide a self-detection function for the arc detection coil 56 and the arc detection unit.

Please refer to FIG. 7 and FIG. 8. The difference between this embodiment and the embodiment shown in FIG. 4 is that the arc detection coil and the current flow sensor are arranged on different circuit boards. Specifically, in this embodiment, the current flow sensor is arranged on the circuit board 30 (see FIG. 2), and the solar inverter further includes a circuit board 50, and the arc detection coil 56 is arranged on the circuit board 50. The circuit board 50 has an opening 53, and the arc detection coil 56 is arranged around the opening 53. The circuit board 50 is mounted on the cable 65 connected to the connection terminal 37 on the circuit board 30. In other words, the cable 65 passes through the opening 53 of the circuit board 50, so that the arc detection coil 56 is surrounded by the cable 65. Therefore, the current from the DC input terminal 25 can pass through the arc detection coil 56 via the cable 65.

Please refer to FIG. 9. In this embodiment, the current sensor (see FIG. 2), the arc detection coil 56, and the self-detection circuit 58 are respectively arranged on the circuit boards 30 and 50, and the circuit board 50 is located between the circuit board 30 and the DC input terminal 25. The DC input terminal 25 is connected to the circuit board 30 through the cable 60. Specifically, one end of the cable 60 is fixedly connected to the DC input terminal 25, and after extending through the opening 53 of the circuit board 50, the other end is fixedly connected to the circuit board 30. The solar inverter further includes an electrical connector 70, which connects the circuit boards 30 and 50 and is electrically connected to the arc detection coil 56 arranged around the opening 53 through the internal line 57 of the circuit board 50. The electrical connector 70 may include a plurality of pins, and the sensing signal generated by the arc detection coil 56 may be transmitted to the circuit board 30 via the internal circuit 57 of the circuit board 50 and the electrical connector 70 .

In some embodiments, the arc detection unit (not shown) is disposed on the circuit board 30, and the sensing signal generated by the arc detection coil 56 is transmitted to the arc detection unit on the circuit board 30 through the electrical connector 70 for analysis. In other embodiments, the arc detection unit may also be disposed on other circuit boards, and the sensing signal generated by the arc detection coil 56 is first transmitted to the circuit board 30 through the electrical connector 70, and then transmitted to the arc detection unit disposed on the other circuit board through other lines for analysis. In some embodiments, the detection circuit controller (not shown) is disposed on the circuit board 30. The detection circuit controller 15 injects a white noise or high-frequency signal into the self-detection circuit 58 through the electrical connector 70 and the internal circuit 59 of the circuit board 50 to provide a self-detection function for the arc detection coil 56 and the arc detection unit.

Please refer to FIG. 10. Different from the embodiment shown in FIG. 9, in this embodiment, the circuit board 30 is fixed on the DC input terminal 25 (for example, fixed by fasteners 90 such as screws), and the circuit board 50 is located between the circuit board 30 and the wall of the housing 20 where the DC input terminal 25 is provided, and is sleeved on the DC input terminal 25 (in other words, the DC input terminal 25 extends through the opening 53 of the circuit board 50). The circuit boards 30 and 50 are connected through the electrical connector 70, and the electrical connector 70 is electrically connected to the arc detection coil 56 provided around the opening 53 through the internal line 57 of the circuit board 50. Some sections of the arc detection coil 56 are provided with a self-detection circuit 58 to provide a self-detection function for the arc detection coil 56 and the arc detection unit.

Please refer to FIG. 11, which shows a partial enlarged cross-sectional view of a circuit board 30/50 according to an embodiment of the present disclosure. This figure shows a cross-sectional view of a 6-layer (L1-L6) copper foil circuit board 30/50, and this part includes the aforementioned arc detection coil 35/56 and self-detection circuit 38/58. In this embodiment, the arc detection coil 35/56 is formed between layer L2 and layer L5 to form a spiral coil, and the self-detection circuit 38/58 is formed between layer L1 and layer L6 to form a spiral coil and surround a portion of the arc detection coil. In this embodiment, the spiral coil of the arc detection coil 35/56 and the spiral coil of the self-detection circuit 38/58 are coaxial (for example, both are centered on the air axis AC). The self-detection circuit 38/58 is configured to inject a white noise or high-frequency signal into the air axis AC to detect whether the arc detection coil 35/56 can detect the white noise or high-frequency signal in the air axis AC, so as to provide a self-detection function for the arc detection coil and the arc detection unit.

Please refer to FIG. 12, which shows a partially enlarged cross-sectional view of a circuit board 30/50 according to another embodiment of the present disclosure. Different from the embodiment shown in FIG. 11, in this embodiment, the arc detection coil 35/56 is formed between layer L2 and layer L5 to form a spiral coil, and the self-detection circuit 38/58 is formed between layer L3 and layer L4 to form a spiral coil and is located in the inner circle of a portion of the arc detection coil. In this embodiment, the spiral coil of the arc detection coil 35/56 and the spiral coil of the self-detection circuit 38/58 are coaxial (for example, both are centered on the air axis AC). The self-detection circuit 38/58 is configured to inject a white noise or a high frequency signal into the air shaft AC to detect whether the arc detection coil 35/56 can detect the white noise or the high frequency signal in the air shaft AC, so as to provide a self-detection function for the arc detection coil and the arc detection unit.

Please refer to FIG. 13, which shows a partial enlarged cross-sectional view of a circuit board 30/50 according to another embodiment of the present disclosure. Different from the embodiments shown in FIGS. 11 and 12, in this embodiment, the circuit board 30/50 is a circuit board with only 4 layers (L1-L4) of copper foil. The arc detection coil 35/56 is formed between layer L2 and layer L3 to form a spiral coil, and the self-detection circuit 38/58 is formed between layer L1 and layer L4 to form a spiral coil and surround a portion of the arc detection coil. In other embodiments, similar to the embodiment of FIG. 12 , the arc detection coil 35/56 is formed between layer L1 and layer L4 to form a spiral coil, and the self-detection circuit 38/58 is formed between layer L2 and layer L3 to form a spiral coil and is located in the inner circle of a partial section of the arc detection coil.

In summary, unlike the existing solar inverter that uses an arc detection coil wound around a ring-shaped core, the solar inverter disclosed herein integrates the arc detection coil and the self-detection circuit on a circuit board, which helps save cost and space, and can more conveniently perform arc detection and self-function detection on each solar string.

Although the present disclosure has been disclosed as above by way of embodiments, it is not intended to limit the present disclosure. Anyone skilled in the art may make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the definition of the attached patent application scope.

10: Solar power system 11: Solar panel 12: Solar inverter 13: Arc detection unit 14: DC switch 15: Detection circuit controller 20: Housing 25: DC input terminal 30: Circuit board 50: Circuit board 31: Opening 53: Opening 32: Internal wiring 57: Internal wiring 33: Inductive flow sensor 35: Arc detection coil 38: Self-detection circuit 56: Arc detection coil 58: Self-detection circuit 37: Connecting terminal 39: Electromagnetic interference suppression capacitor 60: Cable 65: Cable 70: Electrical connector 90: Fasteners L1~L6: Layers AC: Air shaft

In order to make the above and other purposes, features, advantages and embodiments of the present disclosure more clearly understandable, the attached drawings are described as follows: FIG. 1 is a schematic diagram showing a solar power system according to an embodiment of the present disclosure. FIG. 2 is an internal structure diagram of a solar inverter of the solar power system shown in FIG. 1. FIG. 3 is a partially enlarged cross-sectional view showing a solar inverter according to another embodiment of the present disclosure. FIG. 4 is a partially enlarged cross-sectional view showing a solar inverter according to another embodiment of the present disclosure. FIG. 5 is a front view showing the solar inverter shown in FIG. 4. FIG. 6 is a partially enlarged cross-sectional view showing a solar inverter according to another embodiment of the present disclosure. FIG. 7 is a front view showing the second circuit board of the solar inverter shown in FIG. 6. FIG. 8 is a partially enlarged cross-sectional view of a solar inverter according to another embodiment of the present disclosure. FIG. 9 is a partially enlarged cross-sectional view of a solar inverter according to another embodiment of the present disclosure. FIG. 10 is a partially enlarged cross-sectional view of a solar inverter according to another embodiment of the present disclosure. FIG. 11 is a partially enlarged cross-sectional view of a circuit board according to an embodiment of the present disclosure. FIG. 12 is a partially enlarged cross-sectional view of a circuit board according to another embodiment of the present disclosure. FIG. 13 is a partially enlarged cross-sectional view of a circuit board according to yet another embodiment of the present disclosure.

Domestic storage information (please note in the order of storage institution, date, and number) None Foreign storage information (please note in the order of storage country, institution, date, and number) None

12: Solar inverter

20: Shell

25: DC input terminal

30: Circuit board

31: Open mouth

33:Electromagnetic flow detector

35: Arc detection coil

37:Connection terminal

38: Self-test circuit

39: Electromagnetic interference suppression capacitor

60: Cable

Claims (13)

A solar inverter comprises: a housing; at least one circuit board disposed in the housing; an inductive flow sensor disposed on the at least one circuit board; an arc detection coil disposed on the at least one circuit board; a self-detection circuit disposed on the at least one circuit board, wherein the arc detection coil and the spiral coil formed by the self-detection circuit on the at least one circuit board are coaxial; and at least one DC input terminal disposed on the housing and connected to the at least one circuit board, wherein the self-detection circuit is configured to transmit a test signal for the arc detection coil to sense, and the DC input terminal is configured to transmit a current through the arc detection coil, wherein the inductive flow sensor is configured to detect the magnitude of the current passing through the DC input terminal. A solar inverter as described in claim 1, wherein the at least one circuit board includes a first circuit board, and the induction sensor, the self-detection circuit and the arc detection coil are arranged on the first circuit board. The solar inverter as described in claim 2 further comprises a cable connected to the DC input terminal, wherein the first circuit board has an opening, the cable extends through the opening, the arc detection coil is arranged around the opening, and the self-detection circuit is arranged in a partial section of the arc detection coil. The solar inverter as described in claim 2 further comprises a connecting terminal, wherein the first circuit board is fixed on the DC input terminal, the connecting terminal is arranged on the first circuit board and electrically connected to the DC input terminal through an internal circuit of the first circuit board, and the arc detection coil is arranged around the DC input terminal and the connecting terminal. A solar inverter as described in claim 2, wherein the at least one DC input terminal is plural, the first circuit board is configured to receive current from the DC input terminals and output current through at least one output terminal, wherein the number of the at least one output terminal is less than the number of the DC input terminals. The solar inverter as described in claim 2 further comprises an electromagnetic interference suppression capacitor, which is arranged on the first circuit board. The solar inverter as described in claim 1, wherein the at least one circuit board includes a first circuit board and a second circuit board, the current sensor is arranged on the first circuit board, the arc detection coil and the self-detection circuit are arranged on the second circuit board, and the self-detection circuit is arranged on a partial section of the arc detection coil. The solar inverter as described in claim 7 further comprises a cable connected to the DC input terminal and extending through the first circuit board, wherein the second circuit board is mounted on the cable. The solar inverter as described in claim 7 further comprises a connection terminal and a cable, wherein the first circuit board is fixed on the DC input terminal, the connection terminal is arranged on the first circuit board and electrically connected to the DC input terminal through an internal circuit of the first circuit board, the cable is connected to the connection terminal, and the second circuit board is sleeved on the cable. The solar inverter as described in claim 7 further comprises a cable and an electrical connector, the cable is connected between the DC input terminal and the first circuit board and passes through the second circuit board, the electrical connector connects the first circuit board and the second circuit board and is electrically connected to the arc detection coil through an internal circuit of the second circuit board. A solar inverter as described in claim 7, wherein the first circuit board is fixed on the DC input terminal, the second circuit board is located between the first circuit board and a wall of the housing, and is sleeved on the DC input terminal, and the solar inverter further includes an electrical connector, the electrical connector connects the first circuit board and the second circuit board, and is electrically connected to the arc detection coil through an internal circuit of the second circuit board. A solar inverter as described in claim 1, wherein the DC input terminal is configured to connect a solar panel, and the solar inverter further comprises an arc detection unit, the arc detection unit is configured to receive a signal from the arc detection coil, and based on the signal, determine whether an arc fault occurs in the line between the solar inverter and the solar panel, wherein the solar inverter is configured to stop receiving energy from the solar panel when an arc fault occurs. A solar inverter as described in claim 1, wherein the spiral coil formed by the arc detection coil on the at least one circuit board is a ring, and the self-detection circuit is arranged in a partial section of the ring.

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