Photovoltaic inverter and control method thereof

Abstract

This application provides a photovoltaic inverter and a control method thereof. The photovoltaic inverter includes an inverter circuit, a communication circuit, an arc detection circuit, and a transformer. The transformer includes a magnetic core, at least one primary coil, and at least two secondary coils. The primary coil and secondary coil of the transformer are wound around the magnetic core. One end of the first primary coil of the transformer is configured to connect to a power source, and the other end of the first primary coil is configured to connect to an input terminal of the inverter circuit. The first secondary coil of the transformer is configured to connect to the communication circuit, and the second secondary coil of the transformer is configured to connect to the arc detection circuit. By including the magnetic core in the transformer, both power line communication and arc detection are realized. According to this application, the communication circuit and arc detection circuit can be centrally arranged in the inverter, thereby reducing installation space while ensuring power supply safety, reducing design costs of the photovoltaic inverter, and achieving a simple structure, simple method, and high applicability.

Description

[Technical Field]

[0001] [Related Applications] This application claims priority to Chinese Patent Application No. 202310145355.9, entitled "PHOTOVOLTAIC INVERTER AND CONTROL METHODOF," filed with the State Intellectual Property Office of China on February 6, 2023, which is incorporated herein by reference in its entirety. [Technical field] The present application relates to the field of power electronics technology, in particular to a photovoltaic inverter and a control method thereof. [Background technology]

[0002] In the field of power electronics, photovoltaic inverters typically use inverter circuits to convert DC electrical energy into AC electrical energy, enabling electrical energy transmission between a power source and a load. For example, in the field of photovoltaic power supplies, photovoltaic inverters convert DC electrical energy output from a DC power source (e.g., a photovoltaic (PV) panel) into AC electrical energy, which is then supplied to a load or a power grid for use. Photovoltaic inverters typically establish a communication connection to the PV panel via a communication circuit and control the operating current (or voltage) of the photovoltaic inverter or the PV panel based on the operating status of the PV panel and the load (e.g., the load impedance and the PV panel's energy yield) to ensure that the PV panel outputs electrical energy to the load at maximum power. In practical applications, arc faults can generate large noise signals between the photovoltaic inverter and the PV panel. The photovoltaic inverter must detect the noise signal using an arc detection signal. When an arc fault exists in the system, the electrical connection between the photovoltaic inverter and the PV panel is disconnected to ensure the system's power supply safety. In the course of research and practice, the inventors have found that in the prior art, communication circuits and arc detection circuits are often distributed, occupying a large space, requiring high design costs, high power supply costs, and low adaptability. Summary of the Invention

[0003] This application provides a photovoltaic inverter and a control method thereof, which allows a communication circuit and an arc detection circuit to be centrally arranged in the inverter, thereby reducing the arrangement space while ensuring the safety of the power supply, reducing the design cost of the photovoltaic inverter, and providing a simple structure, simple method, and high applicability.

[0004] According to a first aspect, the present application provides a photovoltaic inverter. The photovoltaic inverter may include an inverter circuit, a communication circuit, an arc detection circuit, and a transformer. The transformer may include a magnetic core, at least one primary coil, and at least two secondary coils. The at least one primary coil and the at least two secondary coils are wound around the magnetic core. Here, one end of a first primary coil of the at least one primary coil of the transformer is configured to connect to a power source, and the other end of the first primary coil is configured to connect to an input terminal of the inverter circuit. A first secondary coil of the at least two secondary coils of the transformer is configured to connect to the communication circuit, and a second secondary coil of the transformer is configured to connect to the arc detection circuit. Since the transformer includes the magnetic core, both power line communication and arc detection are realized.

[0005] In the present application, a photovoltaic panel may be used as a power source and connected to a load using a photovoltaic inverter. The photovoltaic inverter can convert DC electrical energy supplied from the photovoltaic panel into AC energy, and the AC energy is provided to the load. Here, the photovoltaic inverter may include an inverter circuit, which may convert DC electrical energy into AC energy so that the electrical energy output by the photovoltaic inverter can be adapted to the AC load. In a photovoltaic power supply scenario, to ensure the efficiency of the photovoltaic power supply, the photovoltaic inverter may supply power using Maximum Power Point Tracking (MPPT) technology, i.e., control the output current of the PV panel (i.e., the input current of the photovoltaic inverter) based on the operating state and load of the PV panel (e.g., based on parameters such as the light conditions and output voltage of the PV panel, and parameters such as the impedance or power of the load) so that the PV cell operates at the maximum power point. Here, the photovoltaic inverter includes a communication circuit, which establishes a power line communication connection with the PV panel using the communication circuit. The photovoltaic inverter or the PV panel can control the operating current (or voltage) of the photovoltaic inverter or the PV panel based on the operating state and load of the PV panel (e.g., the load impedance and the energy yield of the PV panel), allowing the PV panel to output electrical energy to the load at maximum power. In practical applications, the power supply end typically includes multiple PV panels. As a result, the voltage at the DC end of the photovoltaic inverter (i.e., the end of the photovoltaic inverter that connects to the power source) is usually high. If the cable connection at the DC end is aged, has a faulty connector, a mismatched model, or a poor connection, or if two conductors of opposite polarity are close to each other and there is poor insulation between the two wires, an arc may occur as a function of the high voltage, which may endanger the safety of the power supply. Here, the photovoltaic inverter further includes an arc detection circuit, which can perform arc detection based on a noise signal between the photovoltaic inverter and the power source. If an arc is detected in the system, the electrical connection between the photovoltaic inverter and the power supply will be cut off in a timely manner to ensure the safety of the power supply.

[0006] Here, since a communication connection is established between the photovoltaic inverter and the power source to ensure the power supply safety of the system, in order to reduce the design space of the photovoltaic inverter, improve the circuit integration within the photovoltaic inverter, and reduce design costs, the photovoltaic inverter may connect the communication circuit and the arc detection circuit using a transformer so that the communication circuit and the arc detection circuit reuse a magnetic core within the transformer. The transformer may include a magnetic core, at least one primary coil, and at least two secondary coils. Here, the primary coil (e.g., a first primary coil) of the transformer may be connected between the inverter circuit and the power source, one secondary coil (e.g., a first secondary coil) may be connected to the communication circuit, and the other secondary coil (e.g., a second secondary coil) may be connected to the arc detection circuit. Because the primary coil (e.g., the first primary coil) and secondary coil (e.g., the first secondary coil and the second secondary coil) of the transformer are both wound around a magnetic core, the communication circuit and the arc detection circuit may transmit signals (e.g., a power line communication signal and a noise signal) via the primary coil of the transformer and the secondary coils of the transformer connected to the communication circuit and the arc detection circuit. Here, because the frequencies of the power line communication signal and the noise signal are not equal, mutual interference between the two signals can be avoided. It can further be understood that the communication circuit and the arc detection circuit may change parameters of the secondary coils connected to the communication circuit and the arc detection circuit (e.g., change parameters such as the number of turns, coil area, or winding diameter of the first secondary coil and the second secondary coil) so that the primary coil (e.g., the first primary coil) and the secondary coils connected to the communication circuit and the arc detection circuit resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit and the signal strength of the noise signal received by the arc detection circuit. In addition, the communication circuit and the arc detection circuit may perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, respectively, to further improve the transmission accuracy of the power line communication signal or the noise signal and improve the arc detection sensitivity of the photovoltaic inverter.

[0007] According to the present application, the communication circuit and the arc detection circuit can be centrally arranged in the photovoltaic inverter, thereby reducing the arrangement space while ensuring the safety of the power supply, reducing the design cost of the photovoltaic inverter, and providing a simple structure, a simple method, and high applicability.

[0008] Referring to the first aspect, in a first possible implementation, one end of a first primary coil is configured to be connected to a positive output terminal of a power supply, and the other end of the first primary coil is configured to be connected to a positive input terminal of an inverter circuit, and when an AC signal (e.g., a signal such as a noise signal or a power line communication signal) occurs between the power supply and the inverter circuit, the AC signal is transmitted via the primary coil of the transformer to the secondary coil and a circuit (e.g., a circuit such as a communication circuit or an arc detection circuit) connected to the secondary coil.

[0009] Referring to the first aspect or the first possible implementation of the first aspect, in a second possible implementation, at least one primary coil of the transformer may further include a second primary coil. The magnetic core may include a magnetically conductive material. One end of the second primary coil is configured to connect to a power supply. The other end of the second primary coil is configured to connect to an input terminal of the inverter circuit. The first primary coil is coupled to the first secondary coil. The second primary coil is coupled to the second secondary coil. The first primary coil and the first secondary coil, and the second primary coil and the second secondary coil are respectively disposed on two sides of the magnetic core separated by a magnetically conductive material. Here, the arc detection circuit may further perform arc detection between the power supply and the inverter circuit based on noise signals received by the second secondary coil and the second primary coil between the power supply and the inverter circuit.

[0010] Here, the primary coils (e.g., first primary coil and second primary coil) of the transformer may be connected between the inverter circuit and the power supply, one secondary coil (e.g., first secondary coil) may be connected to the communication circuit, and the other secondary coil (e.g., second secondary coil) may be connected to the arc detection circuit. Alternatively, the first primary coil may be coupled to the first secondary coil, and the second primary coil may be coupled to the second secondary coil. Since the primary coils (e.g., first primary coil and second primary coil) and secondary coils (e.g., first secondary coil and second secondary coil) of the transformer are both wound around a magnetic core, the communication circuit and the arc detection circuit may transmit signals (e.g., power line communication signals and noise signals) via the coupled primary coils of the transformer and the secondary coils of the transformer connected to the communication circuit and the arc detection circuit. Here, the frequencies of the power line communication signals and the noise signals are not equal, thereby avoiding mutual interference between the two signals. It can be further understood that the communication circuit and the arc detection circuit can change the parameters of each secondary coil connected to the communication circuit and the arc detection circuit (e.g., changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil and the second secondary coil) to cause the two groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit and the noise signal received by the arc detection circuit. The communication circuit and the arc detection circuit may also perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, respectively, to further improve the transmission accuracy of the power line communication signal or the noise signal. Furthermore, the transformer may further include a magnetic conductive material in the middle of the magnetic core. The magnetic conductive material divides the magnetic core into two sides and shields the signals transmitted on the two sides of the magnetic conductive material within the magnetic core, preventing mutual interference between the signals on the two sides of the magnetic conductive material.That is, two groups of coils in the transformer (e.g., a first primary coil and a first secondary coil, and a second primary coil and a second secondary coil) may be respectively arranged on two sides of the magnetic core separated by a magnetic conductive material, which may be other materials with high magnetic permeability, such as ferrite, amorphous, nanocrystalline, or powder core, and has a simple structure and good adaptability.

[0011] In the present application, the secondary coils connected to the communication circuit and the arc detection circuit may be respectively coupled to two primary coils of the transformer. This improves system integration and increases the flexibility of system design. For example, the parameters of the primary coil and the secondary coil in each group of coupled coils can be individually changed to make the resonant frequency of the coils more variable and adaptable to the frequencies of power line communication signals and noise signals in more application scenarios. Furthermore, by separately wiring and arranging the groups of coupled coils within the photovoltaic inverter, the photovoltaic inverter can be highly integrated and the flexibility and adaptability of its design can be improved.

[0012] Referring to the first aspect or any possible implementation of the first aspect, in a third possible implementation, the photovoltaic inverter further includes an arc self-detection circuit, and the second secondary coil is configured to connect the arc self-detection circuit and the arc detection circuit. Here, the arc self-detection circuit may transmit an arc self-detection signal based on the second secondary coil and the first primary coil, and may simulate a noise signal when an arc exists between the power source and the inverter circuit based on the arc self-detection signal. Here, the frequency of the arc self-detection signal is not equal to the frequency of the power line communication signal between the power source and the inverter circuit. Here, the arc detection circuit may further receive an arc self-detection signal based on the second secondary coil, and may simulate arc detection between the power source and the inverter circuit. Here, the photovoltaic inverter may further include an arc self-detection circuit. The arc self-detection circuit may generate an arc self-detection signal and simulate a noise signal that would be generated if an arc exists at the power source end, thereby testing the detection capability of the arc detection circuit in the photovoltaic inverter. Here, the arc self-detection circuit may be connected to a secondary coil (e.g., a second secondary coil) of the transformer, and the arc self-detection signal generated by the arc self-detection circuit may be transmitted via the second secondary coil to a primary coil (e.g., a first primary coil or a second primary coil) connected to the second secondary coil. Next, the arc detection circuit is coupled to the primary coil (e.g., the first primary coil or the second primary coil) using the secondary coil (e.g., the second secondary coil) connected to the arc detection circuit, and receives the arc self-detection signal transmitted by the primary coil (e.g., the first primary coil or the second primary coil). Here, the frequency of the power line communication signal and the frequency of the arc self-detection signal are not equal, thereby avoiding mutual interference between the two signals.It can be further understood that the communication circuit and the arc self-detection circuit change the parameters of each secondary coil connected to the communication circuit and the arc self-detection circuit (e.g., change the number of turns, coil area, winding diameter, etc. of the first secondary coil and the second secondary coil) to cause the two groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signals transmitted and received by the communication circuit and the signal strength of the arc self-detection signal transmitted by the arc self-detection circuit and received by the arc detection circuit. Furthermore, the communication circuit and the arc detection circuit may each perform filtering based on the frequency of the power line communication signal and the frequency of the arc self-detection signal to further improve the transmission accuracy of the power line communication signal or the arc self-detection signal and improve the arc detection sensitivity of the photovoltaic inverter.

[0013] Referring to the third possible implementation of the first aspect, in a fourth possible implementation, when the photovoltaic inverter includes an arc self-detection circuit, the at least two secondary coils in the transformer further include a third secondary coil. The third secondary coil and the at least one primary coil are wound around a magnetic core. The third secondary coil is coupled to the first primary coil, and the third secondary coil is coupled to the second primary coil. The third secondary coil is configured to connect to the arc self-detection circuit. Here, the arc self-detection circuit may transmit an arc self-detection signal based on the third secondary coil and the first primary coil, and may simulate a noise signal when an arc exists between the power source and the inverter circuit based on the arc self-detection signal.

[0014] Here, a primary coil (e.g., a first primary coil or a second primary coil) of the transformer may be connected between the inverter circuit and the power supply, one secondary coil (e.g., a first secondary coil) may be connected to the communication circuit, a second secondary coil (e.g., a second secondary coil) may be connected to the arc detection circuit, and a third secondary coil (e.g., a third secondary coil) may be connected to the arc self-detection circuit. Alternatively, the first primary coil may be coupled to the first secondary coil, and the second primary coil may be coupled to the second and third secondary coils. When the inverter includes only one primary coil, the first primary coil may be coupled to the first, second, and third secondary coils. Because the primary coils (e.g., first primary coil and second primary coil) and secondary coils (e.g., first secondary coil, second secondary coil, and third secondary coil) of the transformer are all wound around a magnetic core, the communication circuit, the arc detection circuit, and the arc self-detection circuit may transmit signals (e.g., power line communication signals, noise signals, and arc self-detection signals) via the coupled primary coils of the transformer and the secondary coils of the transformer connected to the communication circuit, the arc detection circuit, and the arc self-detection circuit. Here, the frequency of the power line communication signal is not equal to the frequency of the noise signal, and the frequency of the power line communication signal is not equal to the frequency of the arc self-detection signal, so that mutual interference when two signals are transmitted simultaneously in the photovoltaic inverter can be avoided.It can be further understood that the communication circuit, the arc detection circuit, and the arc self-detection circuit can change the parameters of each secondary coil (and the primary coil coupled to the secondary coil) connected to the communication circuit, the arc detection circuit, and the arc self-detection circuit (e.g., changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil, the second secondary coil, and the third secondary coil) to cause groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil, and the third secondary coil; or the first primary coil, the first secondary coil, the second secondary coil, and the third secondary coil) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit, the signal strength of the noise signal received by the arc detection circuit, or the signal strength of the arc self-detection signal received by the arc detection circuit. The communication circuit and the arc detection circuit may also perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, or the frequency of the arc self-detection signal, respectively, to further improve the transmission accuracy of the power line communication signal, the noise signal, or the arc self-detection signal, thereby improving the arc detection sensitivity of the photovoltaic inverter. Furthermore, the transformer may further include a magnetic conductive material in the middle of the magnetic core. The magnetic conductive material divides the magnetic core into two sides, shielding the signals transmitted on the two sides of the magnetic conductive material within the magnetic core and preventing mutual interference between the signals on the two sides of the magnetic conductive material. That is, two groups of coils in the transformer (e.g., the first primary coil and the first secondary coil, and the second primary coil, the second secondary coil, and the third secondary coil) may be arranged on two sides of the magnetic core, separated by a magnetic conductive material. Here, the magnetic conductive material may be other materials with high magnetic permeability, such as ferrite, amorphous, nanocrystalline, or powder core, which have a simple structure and good adaptability.

[0015] With reference to the fourth possible implementation of the first aspect, in a fifth possible implementation, both the first primary coil and the second primary coil have coils wound in opposite directions to suppress the common-mode component of a noise signal. Here, when a noise signal (or an arc self-detection signal) passes through, if the magnetic fluxes of the positive and negative coils generated by the common-mode component of the noise signal (or the arc self-detection signal) are equal, the parameters (e.g., number of turns, coil area, winding diameter) of the coils wound in opposite directions may be the same or different, which can further improve the arc detection accuracy of the system. This method is flexible, easy to operate, and has good adaptability.

[0016] With reference to the first aspect or any possible implementation of the first aspect, in a sixth possible implementation, the arc detection circuit may be further configured to detect the presence of an arc between the power source and the inverter circuit when the amplitude of the noise signal is equal to or greater than a first noise threshold. Here, the arc detection circuit may be further configured to detect the absence of an arc between the power source and the inverter circuit when the amplitude of the noise signal is less than a second noise threshold, where the second noise threshold is equal to or less than the first noise threshold. Here, it will be understood that the value of the first noise threshold (and / or the second noise threshold) may be determined based on the amplitude of the noise signal when an arc occurs in the system, or may be determined based on the first noise threshold (and / or the second noise threshold) acquired, collected, received, detected, stored, or otherwise obtained by the photovoltaic inverter. For example, the photovoltaic inverter or an external central control system may, during the operation process (or design process) of the photovoltaic inverter, calculate the amplitude of the noise signal generated when the photovoltaic system operates normally (no arc is generated) within the noise signal amplitude range, and the arc detection circuit may acquire the first noise threshold (and / or the second noise threshold) based on a relationship curve. This may be specifically set based on the application scenario. It should be understood that the first noise threshold (and / or the second noise threshold) may be a voltage value (current value or power value), a plurality of discrete voltage values ​​(current values ​​or power values), or a voltage range (current range or power range) including a plurality of discrete voltage values ​​(current values ​​or power values) or a continuous voltage value (current value or power value). The second noise threshold may be less than or equal to the first noise threshold. After determining that an arc has occurred when the second noise threshold is less than the first noise threshold, the arc detection circuit can prevent erroneous determination that an arc has been extinguished (or that no arc exists) in the system when the amplitude of the noise signal is sometimes less than the first noise threshold but is not stably less than the first noise threshold.This allows the arc detection circuit to avoid frequent disconnection and connection between the photovoltaic inverter and the power supply, or to avoid incorrectly determining when an arc has occurred and therefore not disconnecting the photovoltaic inverter and the power supply in a timely manner, thereby further improving the power supply safety of the system.

[0017] With reference to the sixth possible implementation of the first aspect, in a seventh possible implementation, the arc detection circuit may be further configured to perform at least one sampling of the noise signal and obtain the amplitude of the noise signal based on a result of the at least one sampling of the noise signal. Here, the arc detection circuit may sample the received noise signal at the same sampling point (or at different sampling points) within a continuous time period (or at multiple time points within a specific time interval), and obtain the amplitude of the noise signal by directly calculating (or averaging or weighted averaging) the result obtained by the sampling, or by performing a calculation such as a discrete Fourier transform or a wavelet transform on the sampling result to obtain the amplitude of the noise signal, thereby further improving the arc detection precision and accuracy of the system.

[0018] According to a second aspect, the present application provides a photovoltaic inverter control method. This control method can be applied to a photovoltaic inverter. The photovoltaic inverter may include an inverter circuit, a communication circuit, an arc detection circuit, and a transformer. The transformer may include a magnetic core, at least one primary coil, and at least two secondary coils. The at least one primary coil and the at least two secondary coils are wound around the magnetic core. One end of a first primary coil of the at least one primary coil of the transformer is configured to connect to a power source, and the other end of the first primary coil is configured to connect to an input terminal of the inverter circuit. A first secondary coil of the at least two secondary coils of the transformer is configured to connect to the communication circuit, and a second secondary coil of the transformer is configured to connect to the arc detection circuit. Both power line communication and arc detection are realized based on the transformer including the magnetic core. The method includes: implementing a power line communication connection between the photovoltaic inverter and the external central control system based on a power line communication signal of the external central control system transmitted and received by the first secondary coil and the first primary coil; and detecting an arc between the power supply and the inverter circuit based on a noise signal received by a second secondary coil and a first primary coil between the power supply and the inverter circuit, wherein the frequency of the noise signal is not equal to the frequency of the power line communication signal.

[0019] In the present application, a photovoltaic panel may be used as a power source and connected to a load using a photovoltaic inverter. The photovoltaic inverter can convert DC electrical energy supplied from the photovoltaic panel into AC energy, and the AC energy is provided to the load. Here, the photovoltaic inverter may include an inverter circuit, which may convert DC electrical energy into AC energy so that the electrical energy output by the photovoltaic inverter can be adapted to the AC load. In a photovoltaic power supply scenario, to ensure the efficiency of the photovoltaic power supply, the photovoltaic inverter may supply power using MPPT technology, i.e., control the output current of the PV panel (i.e., the input current of the photovoltaic inverter) based on the operating state and load of the PV panel (e.g., based on parameters such as the light conditions and output voltage of the PV panel, and parameters such as the impedance or power of the load) so that the PV cell operates at the maximum power point. Here, the photovoltaic inverter includes a communication circuit, which establishes a power line communication connection with the PV panel using the communication circuit. The photovoltaic inverter or the PV panel can control the operating current (or voltage) of the photovoltaic inverter or the PV panel based on the operating state and load of the PV panel (e.g., the load impedance and the energy yield of the PV panel), allowing the PV panel to output electrical energy to the load at maximum power. In practical applications, the power supply end typically includes multiple PV panels. As a result, the voltage at the DC end of the photovoltaic inverter (i.e., the end of the photovoltaic inverter that connects to the power source) is usually high. If the cable connection at the DC end is aged, has a faulty connector, a mismatched model, or a poor connection, or if two conductors of opposite polarity are close to each other and there is poor insulation between the two wires, an arc may occur as a function of the high voltage, which may endanger the safety of the power supply. Here, the photovoltaic inverter further includes an arc detection circuit, which can perform arc detection based on a noise signal between the photovoltaic inverter and the power source. If an arc is detected in the system, the electrical connection between the photovoltaic inverter and the power supply will be cut off in a timely manner to ensure the safety of the power supply.

[0020] Here, since a communication connection is established between the photovoltaic inverter and the power source to ensure the power supply safety of the system, in order to reduce the design space of the photovoltaic inverter, improve the circuit integration within the photovoltaic inverter, and reduce design costs, the photovoltaic inverter may connect the communication circuit and the arc detection circuit using a transformer so that the communication circuit and the arc detection circuit reuse a magnetic core within the transformer. The transformer may include a magnetic core, at least one primary coil, and at least two secondary coils. Here, the primary coil (e.g., a first primary coil) of the transformer may be connected between the inverter circuit and the power source, one secondary coil (e.g., a first secondary coil) may be connected to the communication circuit, and the other secondary coil (e.g., a second secondary coil) may be connected to the arc detection circuit. Because the primary coil (e.g., the first primary coil) and secondary coil (e.g., the first secondary coil and the second secondary coil) of the transformer are both wound around a magnetic core, the communication circuit and the arc detection circuit may transmit signals (e.g., a power line communication signal and a noise signal) via the primary coil of the transformer and the secondary coils of the transformer connected to the communication circuit and the arc detection circuit. Here, because the frequencies of the power line communication signal and the noise signal are not equal, mutual interference between the two signals can be avoided. It can further be understood that the communication circuit and the arc detection circuit may change parameters of the secondary coils connected to the communication circuit and the arc detection circuit (e.g., change parameters such as the number of turns, coil area, or winding diameter of the first secondary coil and the second secondary coil) so that the primary coil (e.g., the first primary coil) and the secondary coils connected to the communication circuit and the arc detection circuit resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit and the signal strength of the noise signal received by the arc detection circuit. In addition, the communication circuit and the arc detection circuit may perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, respectively, to further improve the transmission accuracy of the power line communication signal or the noise signal and improve the arc detection sensitivity of the photovoltaic inverter.

[0021] According to the present application, the communication circuit and the arc detection circuit can be centrally arranged in the photovoltaic inverter, thereby reducing the arrangement space while ensuring the safety of the power supply, reducing the design cost of the photovoltaic inverter, and providing a simple structure, a simple method, and high applicability.

[0022] Referring to the second aspect, in a first possible implementation, at least one primary coil of the transformer may further include a second primary coil. The magnetic core may include a magnetically conductive material. One end of the second primary coil is configured to connect to a power supply. The other end of the second primary coil is configured to connect to an input terminal of the inverter circuit. The first primary coil is coupled to the first secondary coil. The second primary coil is coupled to the second secondary coil. The first primary coil and the first secondary coil, and the second primary coil and the second secondary coil are respectively disposed on two sides of the magnetic core separated by a magnetically conductive material. The method may further include detecting an arc between the power supply and the inverter circuit based on noise signals received by the second secondary coil and the second primary coil between the power supply and the inverter circuit.

[0023] Here, the primary coils (e.g., first primary coil and second primary coil) of the transformer may be connected between the inverter circuit and the power supply, one secondary coil (e.g., first secondary coil) may be connected to the communication circuit, and the other secondary coil (e.g., second secondary coil) may be connected to the arc detection circuit. Alternatively, the first primary coil may be coupled to the first secondary coil, and the second primary coil may be coupled to the second secondary coil. Since the primary coils (e.g., first primary coil and second primary coil) and secondary coils (e.g., first secondary coil and second secondary coil) of the transformer are both wound around a magnetic core, the communication circuit and the arc detection circuit may transmit signals (e.g., power line communication signals and noise signals) via the coupled primary coils of the transformer and the secondary coils of the transformer connected to the communication circuit and the arc detection circuit. Here, the frequencies of the power line communication signals and the noise signals are not equal, thereby avoiding mutual interference between the two signals. It can be further understood that the communication circuit and the arc detection circuit can change the parameters of each secondary coil connected to the communication circuit and the arc detection circuit (e.g., changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil and the second secondary coil) to cause the two groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit and the noise signal received by the arc detection circuit. The communication circuit and the arc detection circuit may also perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, respectively, to further improve the transmission accuracy of the power line communication signal or the noise signal. Furthermore, the transformer may further include a magnetic conductive material in the middle of the magnetic core. The magnetic conductive material divides the magnetic core into two sides and shields the signals transmitted on the two sides of the magnetic conductive material within the magnetic core, preventing mutual interference between the signals on the two sides of the magnetic conductive material.That is, two groups of coils in the transformer (e.g., a first primary coil and a first secondary coil, and a second primary coil and a second secondary coil) may be respectively arranged on two sides of the magnetic core separated by a magnetic conductive material, which may be other materials with high magnetic permeability, such as ferrite, amorphous, nanocrystalline, or powder core, and has a simple structure and good adaptability.

[0024] In the present application, the secondary coils connected to the communication circuit and the arc detection circuit may be respectively coupled to two primary coils of the transformer. This improves system integration and increases the flexibility of system design. For example, the parameters of the primary coil and the secondary coil in each group of coupled coils can be individually changed to make the resonant frequency of the coils more variable and adaptable to the frequencies of power line communication signals and noise signals in more application scenarios. Furthermore, by separately wiring and arranging the groups of coupled coils within the photovoltaic inverter, the photovoltaic inverter can be highly integrated and the flexibility and adaptability of its design can be improved.

[0025] With reference to the second aspect or the first possible implementation of the second aspect, in a second possible implementation, the photovoltaic inverter further includes an arc self-detection circuit, and the second secondary coil is configured to connect the arc self-detection circuit and the arc detection circuit. transmitting an arc self-detection signal based on the second secondary coil and the first primary coil, and simulating a noise signal when an arc exists between the power source and the inverter circuit based on the arc self-detection signal, wherein the frequency of the arc self-detection signal is not equal to the frequency of the power line communication signal between the power source and the inverter circuit; The method may further include receiving an arc self-detection signal based on the second secondary coil to simulate arc detection between the power supply and the inverter circuit.

[0026] Here, the photovoltaic inverter may further include an arc self-detection circuit. The arc self-detection circuit may generate an arc self-detection signal and simulate a noise signal generated when an arc exists at the power supply end to test the detection capability of the arc detection circuit in the photovoltaic inverter. Here, the arc self-detection circuit may be connected to a secondary coil (e.g., a second secondary coil) of the transformer, and may transmit the arc self-detection signal generated by the arc self-detection circuit via the second secondary coil to a primary coil (e.g., a first primary coil or a second primary coil) connected to the second secondary coil. Next, the arc detection circuit is coupled to the primary coil (e.g., a first primary coil or a second primary coil) using the secondary coil (e.g., a second secondary coil) connected to the arc detection circuit, and receives the arc self-detection signal transmitted by the primary coil (e.g., a first primary coil or a second primary coil). Here, since the frequencies of the power line communication signal and the arc self-detection signal are not equal, mutual interference between the two signals can be avoided. It can be further understood that the communication circuit and the arc self-detection circuit change the parameters of each secondary coil connected to the communication circuit and the arc self-detection circuit (e.g., change the number of turns, coil area, winding diameter, etc. of the first secondary coil and the second secondary coil) to cause resonance at different frequencies in the two groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil), thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit and the signal strength of the arc self-detection signal transmitted by the arc self-detection circuit and received by the arc detection circuit. Furthermore, the communication circuit and the arc detection circuit may each perform filtering based on the frequency of the power line communication signal and the frequency of the arc self-detection signal, thereby further improving the transmission accuracy of the power line communication signal or the arc self-detection signal and improving the arc detection sensitivity of the photovoltaic inverter.

[0027] Referring to the second possible implementation of the second aspect, in a third possible implementation, when the photovoltaic inverter includes an arc self-detection circuit, the at least two secondary coils in the transformer further include a third secondary coil. The third secondary coil and the at least one primary coil are wound around a magnetic core. The third secondary coil is coupled to the first primary coil, and the third secondary coil is coupled to the second primary coil. The third secondary coil is configured to connect to the arc self-detection circuit. Before receiving the arc self-detection signal based on the second secondary coil, the method includes: The arc self-detection circuit may further include a step of transmitting an arc self-detection signal based on the third secondary coil and the first primary coil, and simulating a noise signal when an arc exists between the power supply and the inverter circuit based on the arc self-detection signal.

[0028] Here, a primary coil (e.g., a first primary coil or a second primary coil) of the transformer may be connected between the inverter circuit and the power supply, one secondary coil (e.g., a first secondary coil) may be connected to the communication circuit, a second secondary coil (e.g., a second secondary coil) may be connected to the arc detection circuit, and a third secondary coil (e.g., a third secondary coil) may be connected to the arc self-detection circuit. Alternatively, the first primary coil may be coupled to the first secondary coil, and the second primary coil may be coupled to the second and third secondary coils. When the inverter includes only one primary coil, the first primary coil may be coupled to the first, second, and third secondary coils. Because the primary coils (e.g., first primary coil and second primary coil) and secondary coils (e.g., first secondary coil, second secondary coil, and third secondary coil) of the transformer are all wound around a magnetic core, the communication circuit, the arc detection circuit, and the arc self-detection circuit may transmit signals (e.g., power line communication signals, noise signals, and arc self-detection signals) via the coupled primary coils of the transformer and the secondary coils of the transformer connected to the communication circuit, the arc detection circuit, and the arc self-detection circuit. Here, the frequency of the power line communication signal is not equal to the frequency of the noise signal, and the frequency of the power line communication signal is not equal to the frequency of the arc self-detection signal, so that mutual interference when two signals are transmitted simultaneously in the photovoltaic inverter can be avoided.It can be further understood that the communication circuit, the arc detection circuit, and the arc self-detection circuit can change the parameters of each secondary coil (and the primary coil coupled to the secondary coil) connected to the communication circuit, the arc detection circuit, and the arc self-detection circuit (e.g., changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil, the second secondary coil, and the third secondary coil) to cause groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil, and the third secondary coil; or the first primary coil, the first secondary coil, the second secondary coil, and the third secondary coil) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit, the signal strength of the noise signal received by the arc detection circuit, or the signal strength of the arc self-detection signal received by the arc detection circuit. The communication circuit and the arc detection circuit may also perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, or the frequency of the arc self-detection signal, respectively, to further improve the transmission accuracy of the power line communication signal, the noise signal, or the arc self-detection signal, thereby improving the arc detection sensitivity of the photovoltaic inverter. Furthermore, the transformer may further include a magnetic conductive material in the middle of the magnetic core. The magnetic conductive material divides the magnetic core into two sides, shielding the signals transmitted on the two sides of the magnetic conductive material within the magnetic core and preventing mutual interference between the signals on the two sides of the magnetic conductive material. That is, two groups of coils in the transformer (e.g., the first primary coil and the first secondary coil, and the second primary coil, the second secondary coil, and the third secondary coil) may be arranged on two sides of the magnetic core, separated by a magnetic conductive material. Here, the magnetic conductive material may be other materials with high magnetic permeability, such as ferrite, amorphous, nanocrystalline, or powder core, which have a simple structure and good adaptability.

[0029] With reference to the second aspect or any one of the possible implementations of the second aspect, in a fourth possible implementation, the step of detecting an arc between a power source and the inverter circuit based on a noise signal received by a second secondary coil and a first primary coil between the power source and the inverter circuit includes: detecting the presence of an arc between the power source and the inverter circuit when the amplitude of the noise signal is greater than or equal to a first noise threshold; and detecting that no arc exists between the power source and the inverter circuit when the amplitude of the noise signal is less than a second noise threshold, the second noise threshold being less than or equal to the first noise threshold.

[0030] It should be understood that the value of the first noise threshold (and / or the second noise threshold) may be determined based on the amplitude of a noise signal when an arc occurs in the system, or based on the first noise threshold (and / or the second noise threshold) acquired, collected, received, detected, stored, or otherwise obtained by the photovoltaic inverter. For example, the photovoltaic inverter or an external central control system may calculate the amplitude of a noise signal generated when the photovoltaic system operates normally (no arc is generated) within the noise signal amplitude range during the operation (or design) of the photovoltaic inverter, and the arc detection circuit may obtain the first noise threshold (and / or the second noise threshold) based on a relationship curve. This may be specifically set based on the application scenario. It should be understood that the first noise threshold (and / or the second noise threshold) may be a voltage value (current value or power value), a plurality of discrete voltage values ​​(current values ​​or power values), or a voltage range (current range or power range) including a plurality of discrete voltage values ​​(current values ​​or power values) or a continuous voltage value (current value or power value). Furthermore, the second noise threshold may be less than or equal to the first noise threshold. When the second noise threshold is less than the first noise threshold, the arc detection circuit determines that an arc has occurred, and then, if the amplitude of the noise signal is sometimes less than the first noise threshold but is not stably less than the first noise threshold, the arc detection circuit can prevent erroneous determination that the arc in the system has been extinguished (or that no arc exists). This allows the arc detection circuit to avoid frequent disconnections and reconnections between the photovoltaic inverter and the power source, or to avoid failure to timely disconnect the connection between the photovoltaic inverter and the power source due to erroneous determination of when an arc has occurred, thereby further improving the power supply safety of the system.

[0031] With reference to the fourth possible implementation of the second aspect, in a fifth possible implementation, the step of detecting an arc between the power source and the inverter circuit based on a noise signal received by the second secondary coil and the first primary coil between the power source and the inverter circuit includes: The method may further include performing at least one sampling of the noise signal, and obtaining an amplitude of the noise signal based on a result of the at least one sampling of the noise signal.

[0032] Here, the arc detection circuit can further improve the arc detection precision and accuracy of the system by sampling the received noise signal at the same sampling point (or at different sampling points) within a continuous time period (or at multiple time points within a specific time interval), and calculating the sampling results directly (or by averaging or weighted averaging) to obtain the amplitude of the noise signal, or by performing calculations such as a discrete Fourier transform or a wavelet transform on the sampling results to obtain the amplitude of the noise signal. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a diagram of an application scenario of a photovoltaic inverter according to an embodiment of the present application; FIG.

[0034] [Figure 2] FIG. 1 is a structural diagram of a transformer according to an embodiment of the present application.

[0035] [Figure 3] 1 is a schematic diagram of the structure of a photovoltaic inverter according to one embodiment of the present application;

[0036] [Figure 4] FIG. 2 is another structural diagram of a transformer according to an embodiment of the present application.

[0037] [Figure 5] 1 is a schematic diagram of another structure of a photovoltaic inverter according to an embodiment of the present application;

[0038] [Figure 6] FIG. 2 is another structural diagram of a transformer according to an embodiment of the present application.

[0039] [Figure 7] 1 is a schematic diagram of another structure of a photovoltaic inverter according to an embodiment of the present application;

[0040] [Figure 8] FIG. 2 is another structural diagram of a transformer according to an embodiment of the present application.

[0041] [Figure 9] 1 is a schematic flow chart of a control method according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0042] The photovoltaic inverter provided herein can be applied to multiple application fields, such as power generation using renewable energy, peak shaving and frequency modulation in conventional power generation, power supply to important equipment, and new energy vehicles. This can be specifically determined based on the actual application scenario and is not limited thereto. The photovoltaic inverter provided herein can be applied to different power supply systems, such as energy storage systems, uninterruptible power supply systems, and motor drive systems. This can be specifically determined based on the actual application scenario and is not limited thereto. The photovoltaic inverter provided herein can be applied to different application scenarios, such as an application scenario for controlling an inverter circuit in a photovoltaic power supply environment, an application scenario for controlling an inverter circuit in a power supply environment dedicated to photovoltaic energy storage, and other application scenarios. Next, an example of an application scenario for controlling an inverter circuit in a photovoltaic power supply environment will be described. Details will not be described again below.

[0043] Please refer to FIG. 1. FIG. 1 is a diagram of an application scenario of a photovoltaic inverter according to an embodiment of the present application. As shown in FIG. 1, in a power supply system that supplies power only using power storage, the power supply system includes a photovoltaic inverter 1, a power supply 2, and a load 3. The photovoltaic inverter 1 includes an inverter circuit 11. The power supply 2 may be connected to the load 3 via the inverter circuit 11. In some possible implementations, the power supply 2 may supply power to the load 3 via the inverter circuit 11. It should be understood that the power supply 2 provided in the present application can be applied to application scenarios that supply power to multiple types of power consuming devices, such as supplying power to base station equipment in remote locations with no mains or only poor mains, or supplying power to household appliances (such as refrigerators and air conditioners). This can be specifically determined based on the actual application scenario and is not limited here. It should also be understood that the load 3 in FIG. 2 can include a power grid. Here, the power grid can include power consuming devices and power transmitting devices, such as power transmission lines, power transmission stations, communication base stations, and household appliances. Here, the load 3 may further include a load (power consuming device or power transmitting device) having a nonlinear relationship between voltage and current during operation of a motor or a rectifier. In some possible implementations, the photovoltaic inverter may include an inverter circuit 11, which may convert DC electrical energy into AC electrical energy so that the electrical energy output by the photovoltaic inverter can accommodate the AC load. In a photovoltaic power supply scenario, to ensure the efficiency of the photovoltaic power supply, the photovoltaic inverter may supply power using a maximum power point tracking (MPPT) technique. Specifically, the output current of the PV panel (i.e., the input current of the photovoltaic inverter) may be controlled based on the operating state and load of the PV panel (e.g., based on parameters such as the light conditions and output voltage of the PV panel, and parameters such as the impedance or power of the load) to ensure that the PV cell operates at the maximum power point.Here, the photovoltaic inverter includes a communication circuit and establishes a power line communication connection with the PV panel via the communication circuit 12. The photovoltaic inverter controls the operating current (or voltage) of the photovoltaic inverter or the PV panel based on the operating state and load of the PV panel (e.g., the load impedance and the energy yield of the PV panel), allowing the PV panel to output electrical energy to the load at maximum power. In practical applications, the power supply end typically includes multiple PV panels. As a result, the voltage at the DC end of the photovoltaic inverter (i.e., the end of the photovoltaic inverter that connects to the power source) is usually high. If the cable connection at the DC end is aged, has a faulty connector, a mismatched model, or a poor connection, or if two conductors of opposite polarity are close to each other and there is poor insulation between the two wires, an arc may occur as a function of high voltage, potentially endangering the safety of the power supply. Here, the photovoltaic inverter further includes an arc detection circuit that can perform arc detection based on a noise signal between the photovoltaic inverter and the power source. If an arc is detected in the system, the electrical connection between the photovoltaic inverter and the power supply will be cut off in a timely manner to ensure the safety of the power supply.

[0044] Based on the establishment of a communication connection between the photovoltaic inverter and the power source to ensure the power supply safety of the system, it can be understood that the photovoltaic inverter may use a transformer 14 to connect the communication circuit 12 and the arc detection circuit 13, so that the communication circuit 12 and the arc detection circuit 13 reuse the magnetic core in the transformer 14, in order to reduce the design space of the photovoltaic inverter, improve the circuit integration within the photovoltaic inverter, and reduce the design cost. For specific details, please refer to FIG. 2 , which is a structural diagram of a transformer according to an embodiment of the present application. As shown in FIG. 2 , the transformer 14 may include one magnetic core, at least one primary coil, and at least two secondary coils. Here, one end of at least one primary coil (e.g., the first primary coil S1) of the transformer 14 is configured to be connected to a power supply, the other end of the at least one primary coil (e.g., the first primary coil S1) is configured to be connected to the input terminal of the inverter circuit 11, one secondary coil (e.g., the first secondary coil R1) of the at least two secondary coils of the transformer is configured to be connected to the communication circuit 12, and the other secondary coil (e.g., the second secondary coil R2) of the at least two secondary coils of the transformer 14 is configured to be connected to the arc detection circuit 13, and since the transformer 14 includes a magnetic core, both power line communication and arc detection are realized.

[0045] In some possible implementations, one end of at least one primary coil (e.g., the first primary coil S1) of the transformer 14 is configured to be connected to the positive output terminal of the power supply, and the other end of at least one primary coil (e.g., the first primary coil S1) of the transformer 14 is configured to be connected to the positive input terminal of the inverter circuit 11, and when an AC signal (e.g., a noise signal or a power line communication signal) occurs between the power supply and the inverter circuit 11, the AC signal may be transmitted via the primary coil of the transformer 14 to the secondary coil and a circuit (e.g., the communication circuit 12 or the arc detection circuit 13) connected to the secondary coil.

[0046] Here, the first primary coil S1 may have coils wound in opposite directions to suppress the common-mode component of the noise signal. Here, if the magnetic fluxes of the positive and negative coils generated by the common-mode component of the noise signal (or arc self-detection signal) are equal when the noise signal (or arc self-detection signal) passes through, the parameters (e.g., number of turns, coil area, winding diameter) of the coils wound in opposite directions may be the same or different, further improving the arc detection accuracy of the system. This method is flexible, easy to operate, and has good adaptability. It should be understood that the coil winding method and winding position on the magnetic core shown in FIG. 2 are examples for illustrative purposes. Other winding methods and winding positions are also applicable to the present application and may be specifically determined based on the application scenario. This is not limited here. The coil winding method and winding position on the magnetic core in the following structural schematic diagram of the transformer are also examples for illustrative purposes. Details will not be described again here.

[0047] Here, since the primary coil (e.g., first primary coil S1) and secondary coil (e.g., first secondary coil R1 and second secondary coil R2) of the transformer 14 are both wound around a magnetic core, the communication circuit 12 and the arc detection circuit 13 may transmit signals (e.g., power line communication signals and noise signals) via the primary coil of the transformer 14 and the secondary coils of the transformers connected to the communication circuit 12 and the arc detection circuit 13. Here, since the frequency of the power line communication signal and the frequency of the noise signal are not equal, mutual interference between the two signals can be avoided. It will be further understood that the communication circuit 12 and the arc detection circuit 13 may each change parameters of the secondary coils connected to the communication circuit 12 and the arc detection circuit 13 (for example, change parameters such as the number of turns, coil area, or winding diameter of the first secondary coil R1 and the second secondary coil R2) so that the primary coil (for example, the first primary coil S1) and each secondary coil connected to the communication circuit 12 and the arc detection circuit 13 resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit 12 and the signal strength of the noise signal received by the arc detection circuit 13. Furthermore, the communication circuit 12 and the arc detection circuit 13 may each perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal to further improve the transmission accuracy of the power line communication signal or the noise signal and improve the arc detection sensitivity of the photovoltaic inverter.

[0048] According to the present application, the communication circuit and the arc detection circuit can be centrally arranged in the photovoltaic inverter, thereby reducing the arrangement space while ensuring the safety of the power supply, reducing the design cost of the photovoltaic inverter, and providing a simple structure, a simple method, and high applicability.

[0049] Hereinafter, the photovoltaic inverter provided in the present application and the operating principle of the photovoltaic inverter will be described using an example with reference to FIGS.

[0050] In some possible implementations, at least one primary coil of the transformer may further include a second primary coil, and the magnetic core may include a magnetic conductive material. See FIG. 3. FIG. 3 is a schematic diagram of a structure of a photovoltaic inverter according to an embodiment of the present application. As shown in FIG. 3, the photovoltaic inverter includes an inverter circuit 101, a communication circuit 102, an arc detection circuit 103, and a transformer 104. One end of the second primary coil S2 may be configured to connect to a power source. The other end of the second primary coil S2 may be configured to connect to an input terminal of the inverter circuit. The first primary coil S1 is coupled to the first secondary coil R1. The second primary coil S2 is coupled to the second secondary coil R2. The first primary coil S1 and the first secondary coil R1, and the second primary coil S2 and the second secondary coil R2 are respectively arranged on two sides of the magnetic core separated by a magnetic conductive material. Here, the arc detection circuit 103 may further perform arc detection between the power supply and the inverter circuit 101 based on noise signals received by the second secondary coil R2 and the second primary coil S2 between the power supply and the inverter circuit 101.

[0051] Here, primary coils (e.g., a first primary coil S1 and a second primary coil S2) of the transformer 104 may be connected between the inverter circuit 101 and a power supply, one secondary coil (e.g., a first secondary coil R1) may be connected to the communication circuit 102, and the other secondary coil (e.g., a second secondary coil R2) may be connected to the arc detection circuit 103. For specific details, refer to FIG. 4. FIG. 4 is another structural diagram of a transformer according to an embodiment of the present application. As shown in FIG. 4, the first primary coil S1 may be coupled to the first secondary coil R1 (alternatively, the first secondary coil R1 may be disposed at a position opposite to the first primary coil S1, as indicated by the dashed line), and the second primary coil S2 may be coupled to the second secondary coil R2 (alternatively, the second secondary coil R2 may be connected to a position adjacent to the second primary coil S2). The primary coil (e.g., first primary coil S1 and second primary coil S2) and secondary coil (e.g., first secondary coil R1 and second secondary coil R2) of the transformer 104 are both wound around a magnetic core, and therefore the communication circuit 102 and the arc detection circuit 103 may transmit signals (e.g., power line communication signals and noise signals) via the coupled primary coils of the transformer 104 and the secondary coils of the transformers connected to the communication circuit 102 and the arc detection circuit 103. Here, the frequency of the power line communication signal and the frequency of the noise signal are not equal, so mutual interference between the two signals can be avoided. It can be further understood that the communication circuit 102 and the arc detection circuit 103 change the parameters of each secondary coil connected to the communication circuit 102 and the arc detection circuit 103 (for example, by changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil R1 and the second secondary coil R2), thereby causing two groups of coupled coils (for example, the first primary coil S1 and the first secondary coil R1, and the second primary coil S2 and the second secondary coil R2) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit 102 and the signal strength of the noise signal received by the arc detection circuit 103.The communication circuit 102 and the arc detection circuit 103 may also perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, respectively, to further improve the transmission accuracy of the power line communication signal or the noise signal. Both the first primary coil S1 and the second primary coil S2 may include coils wound in opposite directions to suppress the common-mode component of the noise signal. When the noise signal (or arc self-detection signal) passes through, if the magnetic fluxes of the positive and negative coils generated by the common-mode component of the noise signal (or arc self-detection signal) are equal, the parameters (e.g., number of turns, coil area, winding diameter) of the coils wound in opposite directions may be the same or different, further improving the arc detection accuracy of the system. This method is flexible, easy to operate, and has good adaptability. Furthermore, the transformer 104 may further include a magnetic conductive material in the middle of its magnetic core (as shown by the shaded area in FIG. 4). The magnetic conductive material divides the magnetic core into two sides, shielding the signals transmitted on the two sides of the magnetic conductive material within the magnetic core and preventing mutual interference between the signals on the two sides of the magnetic conductive material. That is, two coil groups in a transformer (e.g., the first primary coil S1 and the first secondary coil R1, and the second primary coil S2 and the second secondary coil R2) may be arranged on two sides of the magnetic core separated by the magnetic conductive material. Here, the magnetic conductive material may be other materials with high magnetic permeability, such as ferrite, amorphous, nanocrystalline, or powder core, which has a simple structure and good adaptability.

[0052] In the present application, the secondary coils connected to the communication circuit 102 and the arc detection circuit 103 may be respectively coupled to two primary coils of the transformer 104. This improves system integration and increases the flexibility of system design. For example, parameters of the primary coils and secondary coils in each group of coupled coils can be individually changed to make the resonant frequency of the coils more variable and adaptable to the frequencies of power line communication signals and noise signals in more application scenarios. Furthermore, by separately wiring and arranging the groups of coupled coils within the photovoltaic inverter, the photovoltaic inverter can be highly integrated and the flexibility and adaptability of its design can be increased.

[0053] In some possible implementations, the photovoltaic inverter may further include an arc self-detection circuit. For specific details, see FIG. 5 . FIG. 5 is a schematic diagram of another structure of a photovoltaic inverter according to an embodiment of the present application. As shown in FIG. 5 , the photovoltaic inverter includes an inverter circuit 201, a communication circuit 202, an arc detection circuit 203, a transformer 204, and a self-detection circuit 205. Here, the second secondary coil R2 may be configured to connect to the arc self-detection circuit 205 and the arc detection circuit 203. Here, the arc self-detection circuit 205 may transmit an arc self-detection signal based on the second secondary coil R2 and the first primary coil S1, and may simulate a noise signal when an arc exists between the power source and the inverter circuit 201 based on the arc self-detection signal. Here, the frequency of the arc self-detection signal is not equal to the frequency of the power line communication signal between the power source and the inverter circuit 201. Here, the arc detection circuit 203 may further receive an arc self-detection signal based on the second secondary coil R2 to simulate arc detection between the power supply and the inverter circuit 201. Here, the arc self-detection circuit 205 may generate an arc self-detection signal to simulate a noise signal generated when an arc exists at the power supply end, thereby testing the detection capability of the arc detection circuit 203 in the photovoltaic inverter. 2 and 4, the arc self-detection circuit 205 may be connected to a secondary coil (e.g., the second secondary coil R2) of the transformer 204, and the arc self-detection signal generated by the arc self-detection circuit 205 may be transmitted via the second secondary coil R2 to a primary coil (e.g., the first primary coil S1 or the second primary coil S2) connected to the second secondary coil R2. Next, the arc detection circuit 203 is coupled to a primary coil (e.g., the first primary coil S1 or the second primary coil S2) using a secondary coil (e.g., the second secondary coil R2) connected to the arc detection circuit 203, and receives the arc self-detection signal transmitted by the primary coil (e.g., the first primary coil S1 or the second primary coil S2). Here, the frequency of the power line communication signal and the frequency of the arc self-detection signal are not equal, so mutual interference between the two signals can be avoided.It can be further understood that the communication circuit 202 and the arc self-detection circuit 205 change the parameters of each secondary coil connected to the communication circuit 202 and the arc self-detection circuit 205 (for example, change parameters such as the number of turns, coil area, and winding diameter of the first secondary coil R1 and the second secondary coil R2) to cause resonance at different frequencies in two groups of coupled coils (for example, the first primary coil S1 and the first secondary coil R1, and the second primary coil S2 and the second secondary coil R2), thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit 202 and the signal strength of the arc self-detection signal transmitted by the arc self-detection circuit 205 and received by the arc detection circuit 203. Furthermore, the communication circuit 202 and the arc detection circuit 203 may perform filtering based on the frequency of the power line communication signal and the frequency of the arc self-detection signal, respectively, to further improve the transmission accuracy of the power line communication signal or the arc self-detection signal and improve the arc detection sensitivity of the photovoltaic inverter.

[0054] In some possible implementations, as shown in FIG. 5 , when the photovoltaic inverter may include an arc self-detection circuit 205, the at least two secondary coils of the transformer 204 may further include a third secondary coil (shown by a dashed line in FIG. 5 ). For specific details, please refer to FIG. 6 . FIG. 6 is another structural diagram of a transformer according to an embodiment of the present application. As shown in FIG. 6 , a third secondary coil R3 and a first primary coil S1 may be wound around a magnetic core, the third secondary coil R3 may be coupled to the first primary coil S1, and the third secondary coil R3 may be connected to the arc self-detection circuit 205. Here, the arc self-detection circuit 205 may send an arc self-detection signal based on the third secondary coil R3 and the first primary coil S1, and may simulate a noise signal when an arc exists between the power source and the inverter circuit 201 based on the arc self-detection signal.

[0055] Here, a first primary coil S1 of the transformer 204 may be connected between the inverter circuit 201 and a power supply, one secondary coil (e.g., the first secondary coil R1) may be connected to the communication circuit 202, a second secondary coil (e.g., the second secondary coil R2) may be connected to the arc detection circuit 203, and a third secondary coil (e.g., the third secondary coil R3) may be connected to the arc self-detection circuit 205. Furthermore, the first primary coil S1 may be coupled to the first secondary coil R1, the second secondary coil R2, and the third secondary coil R3. Because the primary coil (e.g., first primary coil S1) and secondary coils (e.g., first secondary coil R1, second secondary coil R2, and third secondary coil R3) of transformer 204 are all wound around a magnetic core, communication circuit 202, arc detection circuit 203, and arc self-detection circuit 205 may transmit signals (e.g., power line communication signals, noise signals, and arc self-detection signals) via the coupled primary coils of transformer 204 and the secondary coils of transformer 204 connected to communication circuit 202, arc detection circuit 203, and arc self-detection circuit 205. Here, the frequencies of the power line communication signals and the noise signals are not equal, and the frequencies of the power line communication signals and the arc self-detection signals are not equal, thereby avoiding mutual interference when two signals are transmitted simultaneously in the photovoltaic inverter. It can be further understood that the communication circuit 202, the arc detection circuit 203, and the arc self-detection circuit 205 can cause groups of coupled coils (e.g., the first primary coil S1 and the first secondary coil R1, the first primary coil S1 and the second secondary coil R2, and the first primary coil S1 and the third secondary coil R3) to resonate at different frequencies by changing the parameters of each secondary coil connected to the communication circuit 202, the arc detection circuit 203, and the arc self-detection circuit 205 (e.g., changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil R1, the second secondary coil R2, and the third secondary coil R3), thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit 202, the signal strength of the noise signal received by the arc detection circuit 203, or the signal strength of the arc self-detection signal received by the arc detection circuit 203.In addition, the communication circuit 202 and the arc detection circuit 203 may each perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, or the frequency of the arc self-detection signal, to further improve the transmission accuracy of the power line communication signal, the noise signal, or the arc self-detection signal, and to improve the arc detection sensitivity of the photovoltaic inverter.

[0056] In some possible implementations, the primary coil of the transformer further includes a second secondary coil, and the photovoltaic inverter includes an arc self-detection circuit. For specific details, see FIG. 7. FIG. 7 is a schematic diagram of another structure of a photovoltaic inverter according to an embodiment of the present application. As shown in FIG. 7, the photovoltaic inverter includes an inverter circuit 301, a communication circuit 302, an arc detection circuit 303, a transformer 304, and an arc self-detection circuit 305. The at least two secondary coils of the transformer 304 may further include a third secondary coil R3. The third secondary coil R3 and at least one primary coil are wound around a magnetic core, and the third secondary coil R3 is coupled to the first primary coil S1, or the third secondary coil R3 is coupled to the second primary coil S2. The arc self-detection circuit 305 is connected to the third secondary coil R3. Here, the arc self-detection circuit 305 may transmit an arc self-detection signal based on the third secondary coil R3 and the second primary coil S2, and may simulate a noise signal when an arc exists between the power supply and the inverter circuit 301 based on the arc self-detection signal.

[0057] Here, a primary coil (e.g., a first primary coil S1 or a second primary coil S2) of the transformer 304 may be connected between the inverter circuit 301 and a power supply, one secondary coil (e.g., a first secondary coil R1) may be connected to the communication circuit 302, a second secondary coil (e.g., a second secondary coil R2) may be connected to the arc detection circuit 303, and a third secondary coil (e.g., a third secondary coil R3) may be connected to the arc self-detection circuit 305. For specific details, refer to FIG. 8. FIG. 8 is another structural diagram of a transformer according to an embodiment of the present application. As shown in FIG. 8, the first primary coil S1 may be coupled to the first secondary coil R1, and the second primary coil S2 may be coupled to the second secondary coil R2 and the third secondary coil R3. Because the primary coil (e.g., first primary coil S1 and second primary coil S2) and secondary coil (e.g., first secondary coil R1, second secondary coil R2, and third secondary coil R3) of the transformer 304 are all wound around a magnetic core, the communication circuit 302, the arc detection circuit 303, and the arc self-detection circuit 305 may transmit signals (e.g., a power line communication signal, a noise signal, and an arc self-detection signal) via the coupled primary coil of the transformer 304 and each secondary coil of the transformer 304 connected to the communication circuit 302, the arc detection circuit 303, and the arc self-detection circuit 305. Here, the frequency of the power line communication signal is not equal to the frequency of the noise signal, and the frequency of the power line communication signal is not equal to the frequency of the arc self-detection signal, so that mutual interference when two signals are transmitted simultaneously in the photovoltaic inverter can be avoided.It can be further understood that the communication circuit 302, the arc detection circuit 303, and the arc self-detection circuit 305 change the parameters of each secondary coil (and primary coil coupled to the secondary coils) connected to the communication circuit 302, the arc detection circuit 303, and the arc self-detection circuit 305 (for example, by changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil R1, the second secondary coil R2, and the third secondary coil R3), thereby causing groups of coupled coils (for example, the first primary coil S1 and the first secondary coil R1, the second primary coil S2 and the second secondary coil R2, and the third secondary coil R3) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit 302, the signal strength of the noise signal received by the arc detection circuit 303, or the signal strength of the arc self-detection signal received by the arc detection circuit 303. In addition, the communication circuit 302 and the arc detection circuit 303 may each perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, or the frequency of the arc self-detection signal, to further improve the transmission accuracy of the power line communication signal, the noise signal, or the arc self-detection signal, and to improve the arc detection sensitivity of the photovoltaic inverter.

[0058] Furthermore, the transformer 304 may further include a magnetic conductive material in the middle of the magnetic core. The magnetic conductive material divides the magnetic core into two sides, shielding signals transmitted on the two sides of the magnetic conductive material within the magnetic core and preventing mutual interference between signals on the two sides of the magnetic conductive material. That is, two groups of coils in the transformer 304 (e.g., the first primary coil S1 and the first secondary coil R1, and the second primary coil S2 and the second secondary coil R2, and the third secondary coil R3) may be respectively arranged on two sides of the magnetic core separated by the magnetic conductive material. Here, the magnetic conductive material may be other materials with high magnetic permeability, such as ferrite, amorphous, nanocrystalline, or powder core, which has a simple structure and good adaptability.

[0059] In the present application, the functional modules of the photovoltaic inverter are formed in a variety of flexibly and can be applied to different application scenarios, thereby improving the diversity of application scenarios of the photovoltaic inverter and enhancing the adaptability of the photovoltaic inverter. Furthermore, in any of the photovoltaic inverters shown in Figures 1 to 8, the communication circuit and the arc detection circuit can be centrally arranged within the inverter, thereby reducing the arrangement space while ensuring the safety of the power supply, reducing the design cost of the photovoltaic inverter, and providing a simple structure, a simple method, and high applicability. For ease of explanation, the drive control method provided in the embodiment of the present application will be described below using the structure of the photovoltaic inverter shown in Figure 1 as an example.

[0060] Please refer to Fig. 9. Fig. 9 is a schematic flowchart of a control method according to the present application. The control method provided in the present application is applicable to photovoltaic inverters including, but not limited to, any of the photovoltaic inverters shown in Figs. 1 to 8. As shown in Fig. 9, the control method provided in the present application includes the following steps:

[0061] S801: Based on the power line communication signals of the external central control system transmitted and received by the first secondary coil and the first primary coil, a power line communication connection is realized between the photovoltaic inverter and the external central control system.

[0062] S802: Perform arc detection between the power supply and the inverter circuit based on a noise signal received by a second secondary coil and a first primary coil between the power supply and the inverter circuit, where the frequency of the noise signal is not equal to the frequency of the power line communication signal.

[0063] In the present application, a photovoltaic panel may be used as a power source and connected to a load using a photovoltaic inverter. The photovoltaic inverter can convert DC electrical energy supplied from the photovoltaic panel into AC energy, and the AC energy is provided to the load. Here, the photovoltaic inverter may include an inverter circuit, which may convert DC electrical energy into AC energy so that the electrical energy output by the photovoltaic inverter can be adapted to the AC load. In a photovoltaic power supply scenario, to ensure the efficiency of the photovoltaic power supply, the photovoltaic inverter may supply power using MPPT technology, i.e., control the output current of the PV panel (i.e., the input current of the photovoltaic inverter) based on the operating state and load of the PV panel (e.g., based on parameters such as the light conditions and output voltage of the PV panel, and parameters such as the impedance or power of the load) so that the PV cell operates at the maximum power point. Here, the photovoltaic inverter includes a communication circuit, which establishes a power line communication connection with the PV panel using the communication circuit. The photovoltaic inverter or the PV panel can control the operating current (or voltage) of the photovoltaic inverter or the PV panel based on the operating state and load of the PV panel (e.g., the load impedance and the energy yield of the PV panel), allowing the PV panel to output electrical energy to the load at maximum power. In practical applications, the power supply end typically includes multiple PV panels. As a result, the voltage at the DC end of the photovoltaic inverter (i.e., the end of the photovoltaic inverter that connects to the power source) is usually high. If the cable connection at the DC end is aged, has a faulty connector, a mismatched model, or a poor connection, or if two conductors of opposite polarity are close to each other and there is poor insulation between the two wires, an arc may occur as a function of the high voltage, which may endanger the safety of the power supply. Here, the photovoltaic inverter further includes an arc detection circuit, which can perform arc detection based on a noise signal between the photovoltaic inverter and the power source. If an arc is detected in the system, the electrical connection between the photovoltaic inverter and the power supply will be cut off in a timely manner to ensure the safety of the power supply.

[0064] Here, since a communication connection is established between the photovoltaic inverter and the power source to ensure the power supply safety of the system, in order to reduce the design space of the photovoltaic inverter, improve the circuit integration within the photovoltaic inverter, and reduce design costs, the photovoltaic inverter may connect the communication circuit and the arc detection circuit using a transformer so that the communication circuit and the arc detection circuit reuse a magnetic core within the transformer. The transformer may include one magnetic core, at least one primary coil, and at least two secondary coils. Here, the primary coil (e.g., a first primary coil) of the transformer may be connected between the inverter circuit and the power source, one secondary coil (e.g., a first secondary coil) may be connected to the communication circuit, and the other secondary coil (e.g., a second secondary coil) may be connected to the arc detection circuit. Because the primary coil (e.g., the first primary coil) and secondary coil (e.g., the first secondary coil and the second secondary coil) of the transformer are both wound around a magnetic core, the communication circuit and the arc detection circuit may transmit signals (e.g., a power line communication signal and a noise signal) via the primary coil of the transformer and the secondary coils of the transformer connected to the communication circuit and the arc detection circuit. Here, because the frequencies of the power line communication signal and the noise signal are not equal, mutual interference between the two signals can be avoided. It can further be understood that the communication circuit and the arc detection circuit may change parameters of the secondary coils connected to the communication circuit and the arc detection circuit (e.g., change parameters such as the number of turns, coil area, or winding diameter of the first secondary coil and the second secondary coil) so that the primary coil (e.g., the first primary coil) and the secondary coils connected to the communication circuit and the arc detection circuit resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit and the signal strength of the noise signal received by the arc detection circuit. In addition, the communication circuit and the arc detection circuit may perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, respectively, to further improve the transmission accuracy of the power line communication signal or the noise signal and improve the arc detection sensitivity of the photovoltaic inverter.

[0065] According to the present application, the communication circuit and the arc detection circuit can be centrally arranged in the photovoltaic inverter, thereby reducing the arrangement space while ensuring the safety of the power supply, reducing the design cost of the photovoltaic inverter, and providing a simple structure, a simple method, and high applicability.

[0066] In some possible implementations, the at least one primary coil of the transformer may further include a second primary coil, and the magnetic core may include a magnetic conductive material. The method may further include detecting an arc between the power source and the inverter circuit based on noise signals received by the second secondary coil and the second primary coil between the power source and the inverter circuit.

[0067] Here, the primary coils (e.g., first primary coil and second primary coil) of the transformer may be connected between the inverter circuit and the power supply, one secondary coil (e.g., first secondary coil) may be connected to the communication circuit, and the other secondary coil (e.g., second secondary coil) may be connected to the arc detection circuit. Alternatively, the first primary coil may be coupled to the first secondary coil, and the second primary coil may be coupled to the second secondary coil. Since the primary coils (e.g., first primary coil and second primary coil) and secondary coils (e.g., first secondary coil and second secondary coil) of the transformer are both wound around a magnetic core, the communication circuit and the arc detection circuit may transmit signals (e.g., power line communication signals and noise signals) via the coupled primary coils of the transformer and the secondary coils of the transformer connected to the communication circuit and the arc detection circuit. Here, the frequencies of the power line communication signals and the noise signals are not equal, thereby avoiding mutual interference between the two signals. It can be further understood that the communication circuit and the arc detection circuit can change the parameters of each secondary coil connected to the communication circuit and the arc detection circuit (e.g., changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil and the second secondary coil) to cause the two groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit and the noise signal received by the arc detection circuit. The communication circuit and the arc detection circuit may also perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, respectively, to further improve the transmission accuracy of the power line communication signal or the noise signal. Furthermore, the transformer may further include a magnetic conductive material in the middle of the magnetic core. The magnetic conductive material divides the magnetic core into two sides and shields the signals transmitted on the two sides of the magnetic conductive material within the magnetic core, preventing mutual interference between the signals on the two sides of the magnetic conductive material.That is, two groups of coils in the transformer (e.g., a first primary coil and a first secondary coil, and a second primary coil and a second secondary coil) may be respectively arranged on two sides of the magnetic core separated by a magnetic conductive material, which may be other materials with high magnetic permeability, such as ferrite, amorphous, nanocrystalline, or powder core, and has a simple structure and good adaptability.

[0068] In the present application, the secondary coils connected to the communication circuit and the arc detection circuit may be respectively coupled to two primary coils of the transformer. This improves system integration and increases the flexibility of system design. For example, the parameters of the primary coil and the secondary coil in each group of coupled coils can be individually changed to make the resonant frequency of the coils more variable and adaptable to the frequencies of power line communication signals and noise signals in more application scenarios. Furthermore, by separately wiring and arranging the groups of coupled coils within the photovoltaic inverter, the photovoltaic inverter can be highly integrated and the flexibility and adaptability of its design can be improved.

[0069] In some possible implementations, the photovoltaic inverter may further include an arc self-detection circuit, and the method includes: transmitting an arc self-detection signal based on the second secondary coil and the first primary coil, and simulating a noise signal when an arc exists between the power supply and the inverter circuit based on the arc self-detection signal, wherein the frequency of the arc self-detection signal is not equal to the frequency of the power line communication signal; The method may further include receiving an arc self-detection signal based on the second secondary coil to simulate arc detection between the power supply and the inverter circuit.

[0070] Here, the photovoltaic inverter may further include an arc self-detection circuit. The arc self-detection circuit may generate an arc self-detection signal and simulate a noise signal generated when an arc exists at the power supply end to test the detection capability of the arc detection circuit in the photovoltaic inverter. Here, the arc self-detection circuit may be connected to a secondary coil (e.g., a second secondary coil) of the transformer, and may transmit the arc self-detection signal generated by the arc self-detection circuit via the second secondary coil to a primary coil (e.g., a first primary coil or a second primary coil) connected to the second secondary coil. Next, the arc detection circuit is coupled to the primary coil (e.g., a first primary coil or a second primary coil) using the secondary coil (e.g., a second secondary coil) connected to the arc detection circuit, and receives the arc self-detection signal transmitted by the primary coil (e.g., a first primary coil or a second primary coil). Here, since the frequencies of the power line communication signal and the arc self-detection signal are not equal, mutual interference between the two signals can be avoided. It can be further understood that the communication circuit and the arc self-detection circuit change the parameters of each secondary coil connected to the communication circuit and the arc self-detection circuit (e.g., change the number of turns, coil area, winding diameter, etc. of the first secondary coil and the second secondary coil) to cause resonance at different frequencies in the two groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil), thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit and the signal strength of the arc self-detection signal transmitted by the arc self-detection circuit and received by the arc detection circuit. Furthermore, the communication circuit and the arc detection circuit may each perform filtering based on the frequency of the power line communication signal and the frequency of the arc self-detection signal, thereby further improving the transmission accuracy of the power line communication signal or the arc self-detection signal and improving the arc detection sensitivity of the photovoltaic inverter.

[0071] In some possible implementations, when the photovoltaic inverter includes an arc self-detection circuit, the at least two secondary coils in the transformer may further include a third secondary coil, and before receiving the arc self-detection signal based on the second secondary coil, the method includes: The arc self-detection circuit may further include a step of transmitting an arc self-detection signal based on the third secondary coil and the first primary coil, and simulating a noise signal when an arc exists between the power supply and the inverter circuit based on the arc self-detection signal.

[0072] Here, a primary coil (e.g., a first primary coil or a second primary coil) of the transformer may be connected between the inverter circuit and the power supply, one secondary coil (e.g., a first secondary coil) may be connected to the communication circuit, a second secondary coil (e.g., a second secondary coil) may be connected to the arc detection circuit, and a third secondary coil (e.g., a third secondary coil) may be connected to the arc self-detection circuit. Alternatively, the first primary coil may be coupled to the first secondary coil, and the second primary coil may be coupled to the second and third secondary coils. When the inverter includes only one primary coil, the first primary coil may be coupled to the first, second, and third secondary coils. Because the primary coils (e.g., first primary coil and second primary coil) and secondary coils (e.g., first secondary coil, second secondary coil, and third secondary coil) of the transformer are all wound around a magnetic core, the communication circuit, the arc detection circuit, and the arc self-detection circuit may transmit signals (e.g., power line communication signals, noise signals, and arc self-detection signals) via the coupled primary coils of the transformer and the secondary coils of the transformer connected to the communication circuit, the arc detection circuit, and the arc self-detection circuit. Here, the frequency of the power line communication signal is not equal to the frequency of the noise signal, and the frequency of the power line communication signal is not equal to the frequency of the arc self-detection signal, so that mutual interference when two signals are transmitted simultaneously in the photovoltaic inverter can be avoided.It can be further understood that the communication circuit, the arc detection circuit, and the arc self-detection circuit can change the parameters of each secondary coil (and the primary coil coupled to the secondary coil) connected to the communication circuit, the arc detection circuit, and the arc self-detection circuit (e.g., changing parameters such as the number of turns, coil area, and winding diameter of the first secondary coil, the second secondary coil, and the third secondary coil) to cause groups of coupled coils (e.g., the first primary coil and the first secondary coil, and the second primary coil and the second secondary coil, and the third secondary coil; or the first primary coil, the first secondary coil, the second secondary coil, and the third secondary coil) to resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit, the signal strength of the noise signal received by the arc detection circuit, or the signal strength of the arc self-detection signal received by the arc detection circuit. The communication circuit and the arc detection circuit may also perform filtering based on the frequency of the power line communication signal and the frequency of the noise signal, or the frequency of the arc self-detection signal, respectively, to further improve the transmission accuracy of the power line communication signal, the noise signal, or the arc self-detection signal, thereby improving the arc detection sensitivity of the photovoltaic inverter. Furthermore, the transformer may further include a magnetic conductive material in the middle of the magnetic core. The magnetic conductive material divides the magnetic core into two sides, shielding the signals transmitted on the two sides of the magnetic conductive material within the magnetic core and preventing mutual interference between the signals on the two sides of the magnetic conductive material. That is, two groups of coils in the transformer (e.g., the first primary coil and the first secondary coil, and the second primary coil, the second secondary coil, and the third secondary coil) may be arranged on two sides of the magnetic core, separated by a magnetic conductive material. Here, the magnetic conductive material may be other materials with high magnetic permeability, such as ferrite, amorphous, nanocrystalline, or powder core, which have a simple structure and good adaptability.

[0073] In some possible implementations, detecting an arc between a power source and the inverter circuit based on a noise signal received by a second secondary coil and a first primary coil between the power source and the inverter circuit includes: detecting the presence of an arc between the power source and the inverter circuit when the amplitude of the noise signal is greater than or equal to a first noise threshold; detecting that no arc exists between the power source and the inverter circuit when the amplitude of the noise signal is less than a second noise threshold, the second noise threshold being less than or equal to the first noise threshold; may include:

[0074] It should be understood that the value of the first noise threshold (and / or the second noise threshold) may be determined based on the amplitude of a noise signal when an arc occurs in the system, or based on the first noise threshold (and / or the second noise threshold) acquired, collected, received, detected, stored, or otherwise obtained by the photovoltaic inverter. For example, the photovoltaic inverter or an external central control system may calculate the amplitude of a noise signal generated when the photovoltaic system operates normally (no arc is generated) within the noise signal amplitude range during the operation (or design) of the photovoltaic inverter, and the arc detection circuit may obtain the first noise threshold (and / or the second noise threshold) based on a relationship curve. This may be specifically set based on the application scenario. It should be understood that the first noise threshold (and / or the second noise threshold) may be a voltage value (current value or power value), a plurality of discrete voltage values ​​(current values ​​or power values), or a voltage range (current range or power range) including a plurality of discrete voltage values ​​(current values ​​or power values) or a continuous voltage value (current value or power value). Furthermore, the second noise threshold may be less than or equal to the first noise threshold. When the second noise threshold is less than the first noise threshold, the arc detection circuit determines that an arc has occurred, and then, if the amplitude of the noise signal is sometimes less than the first noise threshold but is not stably less than the first noise threshold, the arc detection circuit can prevent erroneous determination that the arc in the system has been extinguished (or that no arc exists). This allows the arc detection circuit to avoid frequent disconnections and reconnections between the photovoltaic inverter and the power source, or to avoid failure to timely disconnect the connection between the photovoltaic inverter and the power source due to erroneous determination of when an arc has occurred, thereby further improving the power supply safety of the system.

[0075] In some possible implementations, detecting an arc between the power source and the inverter circuit based on a noise signal received by the second secondary coil and the first primary coil between the power source and the inverter circuit includes: The method may further include performing at least one sampling of the noise signal, and obtaining an amplitude of the noise signal based on a result of the at least one sampling of the noise signal.

[0076] Here, the arc detection circuit can further improve the arc detection precision and accuracy of the system by sampling the received noise signal at the same sampling point (or at different sampling points) within a continuous time period (or at multiple time points within a specific time interval), and calculating the sampling results directly (or by averaging or weighted averaging) to obtain the amplitude of the noise signal, or by performing calculations such as a discrete Fourier transform or a wavelet transform on the sampling results to obtain the amplitude of the noise signal.

[0077] In the present application, the communication circuit and the arc detection circuit can be centrally arranged in the photovoltaic inverter, thereby reducing the arrangement space while ensuring the safety of the power supply, reducing the design cost of the photovoltaic inverter, and providing a simple structure, a simple method, and high applicability.

[0078] The above description is merely a specific implementation of the present invention and is not intended to limit the protection scope of the present invention. Any modifications or replacements that are readily conceived by those skilled in the art within the technical scope disclosed in the present invention should be embraced within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A photovoltaic inverter, the photovoltaic inverter including an inverter circuit, a communication circuit, an arc detection circuit, and a transformer, the transformer including a magnetic core, at least one primary coil, and at least two secondary coils, the at least one primary coil and the at least two secondary coils being wound around the magnetic core; a first primary coil of the at least one primary coil of the transformer configured to have one end connected to a power supply, and the other end of the first primary coil configured to be connected to an input terminal of the inverter circuit; a first secondary coil of the at least two secondary coils of the transformer configured to be connected to the communication circuit; and a second secondary coil of the at least two secondary coils of the transformer configured to be connected to the arc detection circuit, wherein the photovoltaic inverter achieves both power line communication and arc detection based on the transformer including the magnetic core.

2. 2. The photovoltaic inverter of claim 1, wherein the one end of the first primary coil is configured to be connected to a positive output terminal of the power supply, and the other end of the first primary coil is configured to be connected to a positive input terminal of the inverter circuit.

3. the at least one primary coil in the transformer further includes a second primary coil, the magnetic core includes a magnetic conductive material, one end of the second primary coil is configured to be connected to the power supply, and the other end of the second primary coil is configured to be connected to an input terminal of the inverter circuit, the first primary coil is coupled to the first secondary coil, the second primary coil is coupled to the second secondary coil, and the first primary coil, the first secondary coil, the second primary coil, and the second secondary coil are each disposed on two sides of the magnetic core separated by the magnetic conductive material, 3. The photovoltaic inverter according to claim 1, wherein the arc detection circuit is further configured to perform arc detection between the power supply and the inverter circuit based on noise signals received by the second secondary coil and the second primary coil between the power supply and the inverter circuit.

4. the photovoltaic inverter further includes an arc self-detection circuit, and the second secondary coil is configured to connect the arc self-detection circuit and the arc detection circuit; the arc self-detection circuit is configured to transmit an arc self-detection signal based on the second secondary coil and the first primary coil, and to simulate a noise signal when an arc exists between the power supply and the inverter circuit based on the arc self-detection signal, wherein a frequency of the arc self-detection signal is not equal to a frequency of a power line communication signal between the power supply and the inverter circuit; 4. The photovoltaic inverter of claim 1, wherein the arc detection circuit is further configured to receive the arc self-detection signal based on the second secondary coil and simulate arc detection between the power source and the inverter circuit.

5. When the photovoltaic inverter includes the arc self-detection circuit, the at least two secondary coils in the transformer further include a third secondary coil, the third secondary coil and the at least one primary coil are wound around the magnetic core, the third secondary coil is coupled to the first primary coil, or the third secondary coil is coupled to the second primary coil, and the third secondary coil is configured to connect to the arc self-detection circuit; 5. The photovoltaic inverter of claim 4, wherein the arc self-detection circuit is configured to transmit the arc self-detection signal based on the third secondary coil and the first primary coil, and to simulate a noise signal when an arc exists between the power source and the inverter circuit based on the arc self-detection signal.

6. 6. The photovoltaic inverter of claim 5, wherein both the first primary coil and the second primary coil have coils wound in opposite directions to suppress common mode components of the noise signal.

7. the arc detection circuit is further configured to detect the presence of an arc between the power source and the inverter circuit when an amplitude of the noise signal is greater than or equal to a first noise threshold; 7. The photovoltaic inverter of claim 1, wherein the arc detection circuit is further configured to detect the absence of an arc between the power source and the inverter circuit when the amplitude of the noise signal is less than a second noise threshold, the second noise threshold being less than or equal to the first noise threshold.

8. 8. The photovoltaic inverter of claim 7, wherein the arc detection circuit is further configured to perform at least one sampling of the noise signal and obtain an amplitude of the noise signal based on a result of the at least one sampling of the noise signal.

9. A control method for a photovoltaic inverter, the control method being applicable to a photovoltaic inverter, the photovoltaic inverter including an inverter circuit, a communication circuit, an arc detection circuit, and a transformer, the transformer including a magnetic core, at least one primary coil, and at least two secondary coils, the at least one primary coil and the at least two secondary coils being wound around the magnetic core; one end of a first primary coil of the at least one primary coil of the transformer is configured to be connected to a power supply, the other end of the first primary coil is configured to be connected to an input terminal of the inverter circuit, a first secondary coil of the at least two secondary coils of the transformer is configured to be connected to the communication circuit, and a second secondary coil of the at least two secondary coils of the transformer is configured to be connected to the arc detection circuit; The method comprises: implementing a power line communication connection between the photovoltaic inverter and the external central control system based on a power line communication signal of the external central control system transmitted and received by the first secondary coil and the first primary coil; detecting an arc between the power source and the inverter circuit based on a noise signal received by the second secondary coil and the first primary coil between the power source and the inverter circuit, wherein the frequency of the noise signal is not equal to the frequency of the power line communication signal; A control method comprising:

10. the at least one primary coil in the transformer further includes a second primary coil, the magnetic core includes a magnetic conductive material, one end of the second primary coil is configured to be connected to the power supply, and the other end of the second primary coil is configured to be connected to an input terminal of the inverter circuit, the first primary coil is coupled to the first secondary coil, the second primary coil is coupled to the second secondary coil, and the first primary coil, the first secondary coil, the second primary coil, and the second secondary coil are each disposed on two sides of the magnetic core separated by the magnetic conductive material, 10. The control method according to claim 9, further comprising the step of detecting an arc between the power source and the inverter circuit based on noise signals received by the second secondary coil and the second primary coil between the power source and the inverter circuit.

11. the photovoltaic inverter further includes an arc self-detection circuit, and the second secondary coil is configured to connect the arc self-detection circuit and the arc detection circuit; The method comprises: transmitting an arc self-detection signal based on the second secondary coil and the first primary coil, and simulating a noise signal when an arc exists between the power supply and the inverter circuit based on the arc self-detection signal, wherein a frequency of the arc self-detection signal is not equal to a frequency of the power line communication signal; receiving the arc self-detection signal based on the second secondary coil to simulate arc detection between the power source and the inverter circuit; The control method according to claim 9 or 10, further comprising:

12. When the photovoltaic inverter includes the arc self-detection circuit, the at least two secondary coils in the transformer further include a third secondary coil, the third secondary coil and the at least one primary coil are wound around the magnetic core, the third secondary coil is coupled to the first primary coil, or the third secondary coil is coupled to the second primary coil, and the third secondary coil is configured to connect to the arc self-detection circuit; Prior to receiving the arc self-detection signal based on the second secondary coil, the method further comprises: transmitting the arc self-detection signal based on the third secondary coil and the first primary coil, and simulating a noise signal when an arc exists between the power supply and the inverter circuit based on the arc self-detection signal; The control method of claim 11 further comprising:

13. detecting an arc between the power supply and the inverter circuit based on a noise signal received by the second secondary coil and the first primary coil between the power supply and the inverter circuit, detecting the presence of an arc between the power source and the inverter circuit when the amplitude of the noise signal is greater than or equal to a first noise threshold; detecting that no arc exists between the power source and the inverter circuit when the amplitude of the noise signal is less than a second noise threshold, the second noise threshold being less than or equal to the first noise threshold; The control method according to any one of claims 9 to 12, comprising:

14. detecting an arc between the power supply and the inverter circuit based on a noise signal received by the second secondary coil and the first primary coil between the power supply and the inverter circuit, The control method according to claim 13 , further comprising the steps of: performing at least one sampling of the noise signal; and obtaining an amplitude of the noise signal based on a result of the at least one sampling of the noise signal.

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