Photovoltaic inverter and method of controlling the same

Abstract

The application provides a photovoltaic inverter and a control method thereof. The photovoltaic inverter comprises an inverter circuit, a communication circuit, an arc detection circuit and a transformer. The transformer comprises a magnetic core, at least one primary winding and at least two secondary windings. The primary winding and the secondary windings of the transformer are wound on the magnetic core. One end of the first primary winding of the transformer is used for connecting a power supply, the other end of the first primary winding is used for connecting an input end of the inverter circuit, the first secondary winding of the transformer is used for connecting the communication circuit, and the second secondary winding of the transformer is used for connecting the arc detection circuit, so that power line communication and arc detection are realized simultaneously on the basis that the transformer comprises a magnetic core. By using the application, the communication circuit and the arc detection circuit can be arranged in the inverter, the arrangement space is reduced, the design cost of the photovoltaic inverter is reduced, the structure is simple, the method is simple and convenient, and the applicability is strong.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a photovoltaic inverter and its control method. Background Technology

[0002] In the field of power electronics, photovoltaic (PV) inverters are typically used to convert direct current (DC) energy into alternating current (AC) energy, enabling the transfer of electrical energy between the power source and the load. For example, in the photovoltaic power supply field, a PV inverter can convert DC power (e.g., photovoltaic panels) into AC energy to supply the load or the power grid. Typically, the PV inverter needs to establish a communication connection with the PV panels via a communication circuit to control the operating current (or voltage) of the PV inverter or PV panels based on the operating status of the PV panels and the load (e.g., load impedance, PV panel power generation), ensuring that the PV panels output power to the load at maximum power. In practical applications, significant noise signals may be generated between the PV inverter and the PV panels due to arcing faults. The PV inverter needs to detect these noise signals using arc detection signals. If an arcing fault is detected in the system, the electrical connection between the PV inverter and the PV panels should be disconnected to protect the power supply safety of the system. The inventors of this application discovered during their research and practice that, in the prior art, the layout of communication circuits and arc detection circuits is usually quite dispersed, occupying a large space, with high design costs, increasing power supply costs, and having poor adaptability. Summary of the Invention

[0003] This application provides a photovoltaic inverter and its control method, which can centrally deploy the communication circuit and the arc detection circuit in the inverter. While ensuring power supply safety, it reduces the deployment space and lowers the design cost of the photovoltaic inverter. The structure is simple, the method is convenient, and the applicability is strong.

[0004] In a first aspect, this application provides a photovoltaic inverter, which 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 winding, and at least two secondary windings wound around the magnetic core. Here, one end of the first primary winding of the at least one primary winding of the transformer is used to connect to a power source, and the other end of the first primary winding is used to connect to the input terminal of the inverter circuit. The first secondary winding of the at least two secondary windings of the transformer is used to connect to the communication circuit, and the second secondary winding of the at least two secondary windings of the transformer is used to connect to the arc detection circuit, so as to simultaneously realize power line communication and arc detection based on the transformer including a magnetic core.

[0005] In this application, photovoltaic (PV) panels can be used as a power source connected to a load via a PV inverter. The PV inverter converts the DC power provided by the PV panels into AC power to supply the load. Here, the PV inverter may include an inverter circuit that converts DC power into AC power, ensuring that the output power of the PV inverter is compatible with the AC load. In PV power supply scenarios, to ensure the efficiency of PV power supply, the PV inverter can employ Maximum Power Point Tracking (MPPT) technology. This means that, based on the operating states of the PV panels and the load (e.g., parameters such as PV panel illumination conditions, output voltage, and load impedance or power consumption), the output current of the PV panels (i.e., the input current of the PV inverter) is controlled to ensure that the PV panels operate at their maximum power point. Here, the photovoltaic inverter may include a communication circuit to establish a power line communication link with the PV panels. This circuit controls the operating current (or voltage) of the photovoltaic inverter or PV panels based on the operating status of the PV panels and the load (e.g., load impedance, PV panel power generation), ensuring the PV panels output power to the load at maximum capacity. In practical applications, the power supply side typically consists of multiple PV panels, resulting in a generally high voltage at the DC terminal of the photovoltaic inverter (the end connected to the power source). When the DC terminal experiences issues such as aging cable connections, connector failure, model mismatch, loose connections, or when two conductors of opposite polarity are close together and the insulation between the wires fails, an electric arc can easily occur under high voltage, jeopardizing power supply safety. Therefore, the photovoltaic inverter may also include an arc detection circuit. This circuit detects arcs based on noise signals between the photovoltaic inverter and the power source. Upon detecting an arc in the system, it promptly disconnects the electrical connection between the photovoltaic inverter and the power source, ensuring power supply safety.

[0006] It is understandable that, while establishing a communication connection between the photovoltaic inverter and the power supply and ensuring the power supply safety of the system, in order to save design space, improve the integration of the internal circuitry of the photovoltaic inverter, and reduce design costs, the photovoltaic inverter can utilize a transformer to connect the communication circuit and the arc detection circuit together, allowing the communication circuit and the arc detection circuit to reuse the magnetic core in the transformer. The transformer can include a magnetic core, at least one primary winding, and at least two secondary windings. Here, the primary winding of the transformer (e.g., the first primary winding) can be connected between the inverter circuit and the power supply, one secondary winding (e.g., the first secondary winding) can be connected to the communication circuit, and the other secondary winding (e.g., the second secondary winding) can be connected to the arc detection circuit. Since both the primary winding (e.g., the first primary winding) and the secondary windings (e.g., the first secondary winding and the second secondary winding) are wound on the magnetic core, the communication circuit and the arc detection circuit can transmit signals (e.g., power line communication signals and noise signals) with the primary winding of the transformer through their respective connected secondary windings. Here, the frequencies of the power line communication signal and the noise signal are not equal, which avoids mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), causing the primary coil (e.g., the first primary coil) to resonate at different frequencies with the secondary coils connected to the communication circuit and the arc detection circuit, 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. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the noise signal, respectively, further improving the accuracy of the power line communication signal or noise signal transmission and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0007] By adopting this application, the communication circuit and arc detection circuit can be centrally deployed in the photovoltaic inverter, which reduces the deployment space and lowers the design cost of the photovoltaic inverter while ensuring power supply safety. The structure is simple, the method is convenient, and the applicability is strong.

[0008] In conjunction with the first aspect, in a first possible implementation, one end of the first primary coil is used to connect to the positive output terminal of the power supply, and the other end of the first primary coil is used to connect to the positive input terminal of the inverter circuit, so that when an AC signal (e.g., a noise signal or a power line communication signal) appears between the power supply and the inverter circuit, the AC signal can be transmitted through the primary coil of the transformer to the secondary coil and the circuit connected to the secondary coil (e.g., a communication circuit or an arc detection circuit).

[0009] In conjunction with the first aspect or the first possible implementation of the first aspect, in a second possible implementation, at least one primary coil in the transformer may further include a second primary coil. The magnetic core may include a magnetically permeable material. One end of the second primary coil is used to connect to a power supply, and the other end is used to connect to the input terminal of the inverter circuit. The first primary coil is coupled to a first secondary coil, and the second primary coil is coupled to a second secondary coil. The first primary coil and the first secondary coil are arranged on opposite sides of the magnetic core, separated by the magnetically permeable material. The arc detection circuit here may also realize arc detection between the power supply and the inverter circuit based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the second primary coil.

[0010] Here, the primary windings of the transformer (e.g., the first and second primary windings) can be connected between the inverter circuit and the power supply. One secondary winding (e.g., the first secondary winding) can be connected to the communication circuit, and the other secondary winding (e.g., the second secondary winding) can be connected to the arc detection circuit. Simultaneously, the first primary winding can be coupled to the first secondary winding, and the second primary winding can be coupled to the second secondary winding. Since both the primary windings (e.g., the first and second primary windings) and the secondary windings (e.g., the first and second secondary windings) are wound on a magnetic core, the communication circuit and the arc detection circuit can transmit signals (e.g., power line communication signals and noise signals) through their respective connected secondary windings and coupled primary windings in the transformer. Here, the frequencies of the power line communication signal and the noise signal are not equal, which avoids mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), so that the two sets of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) 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. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the noise signal, respectively, further improving the accuracy of the power line communication signal or noise signal transmission. In addition, the transformer core can also include a magnetically conductive material. This material can divide the core into two sides, shielding the signals transmitted on both sides of the magnetically conductive material and preventing mutual interference. In other words, the two sets of coils in the transformer (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) can be arranged on both sides of the core separated by the magnetically conductive material. The magnetic material here can be ferrite, amorphous material, nanocrystalline material, or powder core material, or other materials with high magnetic permeability. It has a simple structure and strong adaptability.

[0011] In this application, the secondary coil connected to the communication circuit and the arc detection circuit can be coupled to the two primary coils in the transformer, respectively. This improves system integration and design freedom. For example, the parameters of the primary and secondary coils in each set of coupled coils can be changed separately, allowing for more varied resonant frequencies to accommodate power line communication signals and noise signals in a wider range of applications. Furthermore, each set of coupled coils can be routed and laid out within the photovoltaic inverter, increasing design flexibility and adaptability while maintaining higher integration.

[0012] In a third possible implementation, in conjunction with the first aspect or any possible embodiment of the first aspect, the photovoltaic inverter may further include an arc self-test circuit, with a second secondary coil used to connect the arc self-test circuit and the arc detection circuit. Here, the arc self-test circuit can send an arc self-test signal based on the second secondary coil and the first primary coil to simulate the noise signal when an arc exists between the power supply and the inverter circuit. The frequency of the arc self-test signal is not equal to the frequency of the power line communication signal between the power supply and the inverter circuit. Here, the arc detection circuit can also receive the arc self-test signal based on the second secondary coil to simulate arc detection between the power supply and the inverter circuit. Here, the photovoltaic inverter may further include an arc self-test circuit that can generate an arc self-test signal to simulate the noise signal generated when an arc exists at the power supply end, thereby testing the detection capability of the arc detection circuit in the photovoltaic inverter. Here, the arc self-detection circuit can be connected to the secondary coil of the transformer (e.g., the second secondary coil). The arc self-detection signal generated by the arc self-detection circuit can be transmitted through the second secondary coil to the primary coil coupled to it (e.g., the first or second primary coil). The arc detection circuit then couples with this primary coil (e.g., the first or second primary coil) through its own connected secondary coil (e.g., the second secondary coil) to receive the arc self-detection signal transmitted by this primary coil (e.g., the first or second primary coil). Here, the power line communication signal and the arc self-detection signal have different frequencies, which avoids mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc self-detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), causing the two sets of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) to resonate at different frequencies. This increases the signal strength of the power line communication signal transmitted and received by the communication circuit and the arc self-detection signal received by the arc detection circuit from the arc self-detection circuit. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the arc self-detection signal, respectively, further improving the accuracy of the power line communication signal or the arc self-detection signal transmission, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0013] In conjunction with the third possible implementation of the first aspect, in the fourth possible implementation, when the photovoltaic inverter may include an arc self-test circuit, at least two secondary coils in the transformer may further include a third secondary coil. The third secondary coil and at least one primary coil are wound around a magnetic core. The third secondary coil is coupled to the first primary coil, or coupled to the second primary coil. The third secondary coil is used to connect to the arc self-test circuit. Here, the arc self-test circuit can send an arc self-test signal based on the third secondary coil and the first primary coil to simulate noise signals when an arc exists between the power supply and the inverter circuit.

[0014] Here, the primary winding of the transformer (e.g., a first primary winding or a second primary winding) can be connected between the inverter circuit and the power supply. A secondary winding (e.g., a first secondary winding) can be connected to a communication circuit, a second secondary winding (e.g., a second secondary winding) can be connected to an arc detection circuit, and a third secondary winding (e.g., a third secondary winding) can be connected to an arc self-detection circuit. Simultaneously, the first primary winding can be coupled to the first secondary winding, and the second primary winding can be coupled to the second and third secondary windings. When the inverter includes only one primary winding, the first primary winding can be coupled to the first, second, and third secondary windings. Since the primary windings (e.g., the first and second primary windings) and secondary windings (e.g., the first, second, and third secondary windings) of the transformer are all wound on a magnetic core, the communication circuit, the arc detection circuit, and the arc self-test circuit can transmit signals (e.g., power line communication signals, noise signals, and arc self-test signals) to the coupled primary windings in the transformer via their respective connected secondary windings. Here, the frequencies of the power line communication signal and the noise signal are not equal, and the frequencies of the power line communication signal and the arc self-test signal are also not equal, which avoids mutual interference when the two signals are transmitted simultaneously inside the photovoltaic inverter. Furthermore, it can be understood that the communication circuit, arc detection circuit, and arc self-test circuit can respectively change the parameters of their connected secondary coils (and the primary coils coupled to each secondary coil) (e.g., changing the number of turns, coil area, or winding diameter of the first, second, and third secondary coils), so that each pair of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil, and the third secondary coil; or the first primary coil and the first secondary coil, the second secondary coil, and the third secondary coil) resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit, the noise signal received by the arc detection circuit, or the arc self-test signal received by the arc detection circuit. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequency of the power line communication signal, the noise signal, or the arc self-test signal, further improving the accuracy of the transmission of the power line communication signal, the noise signal, or the arc self-test signal, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs. Furthermore, the transformer core may also include a magnetically conductive material. This material divides the core into two sides, shielding the signals transmitted on both sides and preventing mutual interference. In other words, the two sets of coils in the transformer (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil, and the third secondary coil) can be arranged on either side of the core separated by the magnetically conductive material. This magnetically conductive material can be ferrite, amorphous materials, nanocrystalline materials, or powder cores, or other materials with high permeability, offering a simple structure and strong adaptability.

[0015] In conjunction with the fourth possible implementation of the first aspect, in the fifth possible implementation, both the first primary coil and the second primary coil have coils wound in opposite directions to suppress common-mode components in the noise signal. Here, the parameters of the coils wound in opposite directions (e.g., number of turns, coil area, winding diameter, etc.) can be the same or different, as long as they satisfy the requirement that the magnetic flux generated by the common-mode components of the noise signal (or arc self-detection signal) in the positive and negative coils is equal in magnitude when the noise signal (or arc self-detection signal) passes through. This can further improve the accuracy of arc detection in the system, and the method is flexible, easy to operate, and highly adaptable.

[0016] In conjunction with the first aspect or any possible implementation thereof, in a sixth possible implementation, the arc detection circuit can also be used to detect the existence of an arc between the power supply and the inverter circuit when the amplitude of the noise signal is greater than or equal to a first noise threshold. The arc detection circuit can also be used to detect the absence of an arc between the power supply and the inverter circuit when the amplitude of the noise signal is less than a second noise threshold, where the second noise threshold is less than or equal to the first noise threshold. It is understood that the value of the first noise threshold (and / or the second noise threshold) can be determined based on the amplitude of the noise signal when an arc occurs in the system, or it can be determined based on the first noise threshold (and / or the second noise threshold) obtained by the photovoltaic inverter through acquisition, collection, reception, detection, or storage. For example, the photovoltaic inverter or the external central control system can calculate the amplitude of the noise signal generated when the photovoltaic system is operating normally (without an arc) within a certain noise signal amplitude range during the operation (or design) of the photovoltaic inverter. The arc detection circuit can then obtain the first noise threshold (and / or the second noise threshold) based on this relationship curve, which can be specifically set according to the application scenario. It is understood that the first noise threshold (and / or the second noise threshold) here can be a voltage value (or a current value or a power value), multiple discrete voltage values ​​(or current values ​​or power values), a voltage range (or current range or power range) composed of multiple discrete voltage values ​​(or current values ​​or power values) or continuous voltage values ​​(or current values ​​or power values). Meanwhile, the second noise threshold here can be less than or equal to the first noise threshold. When the second noise threshold is less than the first noise threshold, it can prevent the arc detection circuit from mistakenly determining that the arc in the system has disappeared (or that the arc does not exist) after detecting the occurrence of an arc, when the amplitude of the noise signal is occasionally less than the first noise threshold but not consistently less than the first noise threshold. Furthermore, the arc detection circuit can avoid frequently switching the connection between the photovoltaic inverter and the power supply, or avoid failing to switch the connection between the photovoltaic inverter and the power supply in a timely manner due to misjudgment when an arc occurs, further improving the safety of the system power supply.

[0017] In conjunction with the sixth possible implementation of the first aspect, in the seventh possible implementation, the arc detection circuit can also be used to sample the noise signal at least once, and obtain the amplitude of the noise signal based on the result of the at least one sampling of the noise signal. Here, the arc detection circuit can sample the received noise signal at the same sampling point (or multiple different sampling points) within a continuous time period (or at multiple time points with a certain time interval), and directly (or average, or after weighted averaging) calculate the amplitude of the noise signal from the sampled results, or perform calculations such as discrete Fourier transform or wavelet transform on the sampled results before obtaining the amplitude of the noise signal, thereby further improving the arc detection accuracy and precision of the system.

[0018] Secondly, this application provides a control method for a photovoltaic inverter. This control method is applicable to photovoltaic inverters, which 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 winding, and at least two secondary windings wound around the magnetic core. One end of the first primary winding of the at least one primary winding is connected to a power source, and the other end is connected to the input terminal of the inverter circuit. The first secondary winding of the at least two secondary windings of the transformer is connected to the communication circuit, and the second secondary winding of the at least two secondary windings of the transformer is connected to the arc detection circuit. This allows for simultaneous power line communication and arc detection based on the transformer including a magnetic core. The method may include:

[0019] The power line communication link between the photovoltaic inverter and the external control system is achieved based on the power line communication signals transmitted and received by the first secondary coil and the first primary coil. Arc detection between the power supply and the inverter circuit is achieved based on the noise signals received by the second secondary coil and the first primary coil; the frequency of the noise signals is not equal to the frequency of the power line communication signals.

[0020] In this application, photovoltaic (PV) panels can be used as a power source connected to a load via a PV inverter. The PV inverter converts the DC power provided by the PV panels into AC power to supply the load. Here, the PV inverter may include an inverter circuit that converts DC power into AC power, ensuring the output power of the PV inverter is compatible with the AC load. In PV power supply scenarios, to ensure the efficiency of PV power supply, the PV inverter may employ MPPT (Maximum Power Point Test) technology. This means controlling the output current of the PV panels (i.e., the input current of the PV inverter) based on the operating states of the PV panels and the load (e.g., parameters such as PV panel illumination conditions, output voltage, and load impedance or power consumption), so that the PV panels operate at their maximum power point. Here, the PV inverter may include a communication circuit that establishes a power line communication link with the PV panels to control the operating current (or voltage) of the PV inverter or PV panels based on the operating states of the PV panels and the load (e.g., load impedance, PV panel power generation), enabling the PV panels to output power to the load at maximum power. Meanwhile, in practical applications, the power supply side typically consists of multiple PV panels, resulting in a generally high voltage at the DC end of the photovoltaic inverter (i.e., the end where the photovoltaic inverter connects to the power supply). When the DC end experiences issues such as aging cable connections, connector failure, model mismatch, loose connections, or when two conductors with opposite polarities are very close together and the insulation between the two wires fails, an electric arc is highly likely to occur under high voltage, jeopardizing power supply safety. Therefore, the photovoltaic inverter can also include an arc detection circuit. This circuit detects arcs based on noise signals between the photovoltaic inverter and the power supply, and promptly disconnects the electrical connection between the photovoltaic inverter and the power supply when an arc is detected, ensuring power supply safety.

[0021] It is understandable that, while establishing a communication connection between the photovoltaic inverter and the power supply and ensuring the power supply safety of the system, in order to save design space, improve the integration of the internal circuitry of the photovoltaic inverter, and reduce design costs, the photovoltaic inverter can utilize a transformer to connect the communication circuit and the arc detection circuit together, allowing the communication circuit and the arc detection circuit to reuse the magnetic core in the transformer. The transformer can include a magnetic core, at least one primary winding, and at least two secondary windings. Here, the primary winding of the transformer (e.g., the first primary winding) can be connected between the inverter circuit and the power supply, one secondary winding (e.g., the first secondary winding) can be connected to the communication circuit, and the other secondary winding (e.g., the second secondary winding) can be connected to the arc detection circuit. Since both the primary winding (e.g., the first primary winding) and the secondary windings (e.g., the first secondary winding and the second secondary winding) are wound on the magnetic core, the communication circuit and the arc detection circuit can transmit signals (e.g., power line communication signals and noise signals) with the primary winding of the transformer through their respective connected secondary windings. Here, the frequencies of the power line communication signal and the noise signal are not equal, which avoids mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), causing the primary coil (e.g., the first primary coil) to resonate at different frequencies with the secondary coils connected to the communication circuit and the arc detection circuit, 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. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the noise signal, respectively, further improving the accuracy of the power line communication signal or noise signal transmission and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0022] By adopting this application, the communication circuit and arc detection circuit can be centrally deployed in the photovoltaic inverter, which reduces the deployment space and lowers the design cost of the photovoltaic inverter while ensuring power supply safety. The structure is simple, the method is convenient, and the applicability is strong.

[0023] In conjunction with the second aspect, in a first possible implementation, at least one primary coil in the transformer may further include a second primary coil. The magnetic core may include a magnetically permeable material. One end of the second primary coil is used to connect to a power supply, and the other end of the second primary coil is used to connect to the input terminal of the inverter circuit. The first primary coil is coupled to the first secondary coil, and the second primary coil is coupled to the second secondary coil. The first primary coil and the first secondary coil are arranged on both sides of the magnetic core separated by the magnetically permeable material. The method may further include: detecting an electric arc between the power supply and the inverter circuit based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the second primary coil.

[0024] Here, the primary windings of the transformer (e.g., the first and second primary windings) can be connected between the inverter circuit and the power supply. One secondary winding (e.g., the first secondary winding) can be connected to the communication circuit, and the other secondary winding (e.g., the second secondary winding) can be connected to the arc detection circuit. Simultaneously, the first primary winding can be coupled to the first secondary winding, and the second primary winding can be coupled to the second secondary winding. Since both the primary windings (e.g., the first and second primary windings) and the secondary windings (e.g., the first and second secondary windings) are wound on a magnetic core, the communication circuit and the arc detection circuit can transmit signals (e.g., power line communication signals and noise signals) through their respective connected secondary windings and coupled primary windings in the transformer. Here, the frequencies of the power line communication signal and the noise signal are not equal, which avoids mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), so that the two sets of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) 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. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the noise signal, respectively, further improving the accuracy of the power line communication signal or noise signal transmission. In addition, the transformer core can also include a magnetically conductive material. This material can divide the core into two sides, shielding the signals transmitted on both sides of the magnetically conductive material and preventing mutual interference. In other words, the two sets of coils in the transformer (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) can be arranged on both sides of the core separated by the magnetically conductive material. The magnetic material here can be ferrite, amorphous material, nanocrystalline material, or powder core material, or other materials with high magnetic permeability. It has a simple structure and strong adaptability.

[0025] In this application, the secondary coil connected to the communication circuit and the arc detection circuit can be coupled to the two primary coils in the transformer, respectively. This improves system integration and design freedom. For example, the parameters of the primary and secondary coils in each set of coupled coils can be changed separately, allowing for more varied resonant frequencies to accommodate power line communication signals and noise signals in a wider range of applications. Furthermore, each set of coupled coils can be routed and laid out within the photovoltaic inverter, increasing design flexibility and adaptability while maintaining higher integration.

[0026] In conjunction with the second aspect or the first possible implementation of the second aspect, in the second possible implementation, the photovoltaic inverter may further include an arc self-test circuit, a second secondary coil for connecting the arc self-test circuit and the arc detection circuit, and the method may further include:

[0027] An arc self-test signal is transmitted based on the second secondary coil and the first primary coil to simulate the noise signal when an arc exists between the power supply and the inverter circuit. The frequency of the arc self-test signal is not equal to the frequency of the power line communication signal between the power supply and the inverter circuit. The arc self-test signal is received based on the second secondary coil to simulate arc detection between the power supply and the inverter circuit.

[0028] Here, the photovoltaic inverter may also include an arc self-test circuit. This circuit generates an arc self-test signal to simulate the noise signal generated when an arc exists at the power supply end, thereby testing the detection capability of the arc detection circuit within the photovoltaic inverter. The arc self-test circuit can be connected to the secondary coil of the transformer (e.g., the second secondary coil). The arc self-test signal generated by the circuit can be transmitted through the second secondary coil to the primary coil coupled to it (e.g., the first or second primary coil). The arc detection circuit then couples with this primary coil (e.g., the first or second primary coil) through its connected secondary coil (e.g., the second secondary coil) to receive the arc self-test signal transmitted by this primary coil (e.g., the first or second primary coil). Here, the power line communication signal and the arc self-test signal have different frequencies to avoid mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc self-detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), causing the two sets of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) to resonate at different frequencies. This increases the signal strength of the power line communication signal transmitted and received by the communication circuit and the arc self-detection signal received by the arc detection circuit from the arc self-detection circuit. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the arc self-detection signal, respectively, further improving the accuracy of the power line communication signal or the arc self-detection signal transmission, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0029] In conjunction with the second possible implementation of the second aspect, in the third possible implementation, when the photovoltaic inverter may include an arc self-test circuit, at least two secondary coils in the transformer may further include a third secondary coil. The third secondary coil and at least one primary coil are wound around a 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. The third secondary coil is used to connect to the arc self-test circuit. Before receiving the arc self-test signal based on the second secondary coil, the method may further include:

[0030] An arc self-test signal is sent based on the third secondary coil and the first primary coil to simulate the noise signal when there is an arc between the power supply and the inverter circuit.

[0031] Here, the primary winding of the transformer (e.g., a first primary winding or a second primary winding) can be connected between the inverter circuit and the power supply. A secondary winding (e.g., a first secondary winding) can be connected to a communication circuit, a second secondary winding (e.g., a second secondary winding) can be connected to an arc detection circuit, and a third secondary winding (e.g., a third secondary winding) can be connected to an arc self-detection circuit. Simultaneously, the first primary winding can be coupled to the first secondary winding, and the second primary winding can be coupled to the second and third secondary windings. When the inverter includes only one primary winding, the first primary winding can be coupled to the first, second, and third secondary windings. Since the primary windings (e.g., the first and second primary windings) and secondary windings (e.g., the first, second, and third secondary windings) of the transformer are all wound on a magnetic core, the communication circuit, the arc detection circuit, and the arc self-test circuit can transmit signals (e.g., power line communication signals, noise signals, and arc self-test signals) to the coupled primary windings in the transformer via their respective connected secondary windings. Here, the frequencies of the power line communication signal and the noise signal are not equal, and the frequencies of the power line communication signal and the arc self-test signal are also not equal, which avoids mutual interference when the two signals are transmitted simultaneously inside the photovoltaic inverter. Furthermore, it can be understood that the communication circuit, arc detection circuit, and arc self-test circuit can respectively change the parameters of their connected secondary coils (and the primary coils coupled to each secondary coil) (e.g., changing the number of turns, coil area, or winding diameter of the first, second, and third secondary coils), so that each pair of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil, and the third secondary coil; or the first primary coil and the first secondary coil, the second secondary coil, and the third secondary coil) resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit, the noise signal received by the arc detection circuit, or the arc self-test signal received by the arc detection circuit. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequency of the power line communication signal, the noise signal, or the arc self-test signal, further improving the accuracy of the transmission of the power line communication signal, the noise signal, or the arc self-test signal, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs. Furthermore, the transformer core may also include a magnetically conductive material. This material divides the core into two sides, shielding the signals transmitted on both sides and preventing mutual interference. In other words, the two sets of coils in the transformer (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil, and the third secondary coil) can be arranged on either side of the core separated by the magnetically conductive material. This magnetically conductive material can be ferrite, amorphous materials, nanocrystalline materials, or powder cores, or other materials with high permeability, offering a simple structure and strong adaptability.

[0032] In conjunction with the second aspect or any possible implementation of the second aspect, in a fourth possible implementation, arc detection between the power supply and the inverter circuit is achieved based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the first primary coil, which may include:

[0033] When the amplitude of the noise signal is greater than or equal to the first noise threshold, an electric arc is detected between the power supply and the inverter circuit. When the amplitude of the noise signal is less than the second noise threshold, no electric arc is detected between the power supply and the inverter circuit, and the second noise threshold is less than or equal to the first noise threshold.

[0034] It is understood that the value of the first noise threshold (and / or the second noise threshold) here can be determined based on the amplitude of the noise signal when an electric arc occurs in the system, or it can be determined based on the first noise threshold (and / or the second noise threshold) obtained by the photovoltaic inverter through acquisition, collection, reception, detection, or storage. For example, the photovoltaic inverter or the external central control system can calculate the amplitude of the noise signal generated when the photovoltaic system is working normally (without an electric arc) within a certain noise signal amplitude range during the operation of the photovoltaic inverter (or during the design process). Then, the arc detection circuit can obtain the first noise threshold (and / or the second noise threshold) based on this relationship curve, which can be set according to the application scenario. It is understood that the first noise threshold (and / or the second noise threshold) here can be a voltage value (or a current value or a power value), can be multiple discrete voltage values ​​(or current values ​​or power values), can be a voltage range (or current range or power range) composed of multiple discrete voltage values ​​(or current values ​​or power values) or continuous voltage values ​​(or current values ​​or power values). Meanwhile, the second noise threshold can 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 can avoid mistakenly determining that the arc in the system has disappeared (or that the arc does not exist) when the amplitude of the noise signal is occasionally less than the first noise threshold after detecting the occurrence of an arc. Furthermore, the arc detection circuit can avoid frequently switching the connection between the photovoltaic inverter and the power supply, or avoid failing to switch the connection between the photovoltaic inverter and the power supply in time due to misjudgment when an arc occurs, thus further improving the safety of the system power supply.

[0035] In conjunction with the fourth possible implementation of the second aspect, in the fifth possible implementation, the arc detection between the power supply and the inverter circuit is realized based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the first primary coil, and may further include:

[0036] The noise signal is sampled at least once, and the amplitude of the noise signal is obtained based on the result of the at least once sampling.

[0037] Here, the arc detection circuit can sample the received noise signal at the same sampling point (or multiple different sampling points) within a continuous time period (or at multiple time points with a certain time interval), and directly (or average, or after weighted averaging) calculate the amplitude of the noise signal from the sampled results, or perform calculations such as discrete Fourier transform or wavelet transform on the sampled results to obtain the amplitude of the noise signal, thereby further improving the arc detection accuracy and precision of the system. Attached Figure Description

[0038] Figure 1 This is a schematic diagram illustrating the application scenario of the photovoltaic inverter provided in the embodiments of this application;

[0039] Figure 2 This is a schematic diagram of a transformer provided in an embodiment of this application;

[0040] Figure 3 This is a schematic diagram of the structure of a photovoltaic inverter provided in an embodiment of this application;

[0041] Figure 4 This is another structural schematic diagram of the transformer provided in the embodiments of this application;

[0042] Figure 5 This is another structural schematic diagram of the photovoltaic inverter provided in the embodiments of this application;

[0043] Figure 6 This is another structural schematic diagram of the transformer provided in the embodiments of this application;

[0044] Figure 7 This is another structural schematic diagram of the photovoltaic inverter provided in the embodiments of this application;

[0045] Figure 8 This is another structural schematic diagram of the transformer provided in the embodiments of this application;

[0046] Figure 9 This is a flowchart illustrating the control method provided in the embodiments of this application. Detailed Implementation

[0047] The photovoltaic inverter provided in this application can be applied to various fields, including new energy power generation, traditional power generation peak shaving and frequency regulation, power supply for critical equipment, and new energy vehicles. The specific application scenario can be determined accordingly, and no limitations are imposed here. The photovoltaic inverter provided in this application can also be applied to different power supply systems, such as energy storage systems, uninterruptible power supply systems, and motor drive systems. The specific application scenario can be determined according to the actual application scenario, and no limitations are imposed here. The photovoltaic inverter provided in this application is adaptable to different application scenarios, such as applications controlling inverter circuits in photovoltaic power supply environments, applications controlling inverter circuits in photovoltaic pure energy storage power supply environments, or other application scenarios. The following explanation will use the application scenario of controlling inverter circuits in a photovoltaic power supply environment as an example, and will not be elaborated further.

[0048] Please see Figure 1 , Figure 1 This is a schematic diagram illustrating an application scenario of the photovoltaic inverter provided in this application embodiment. In a pure energy storage power supply system, such as... Figure 1 As shown, 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, and the power supply 2 can be connected to the load 3 via the inverter circuit 11. In some feasible embodiments, the power supply 2 can supply power to the load 3 via the inverter circuit 11. It is understood that the power supply 2 provided in this application is suitable for powering base station equipment in remote areas with no or poor mains power, or for powering household appliances (such as refrigerators, air conditioners, etc.), and other application scenarios involving powering various types of electrical equipment. The specific application scenario can be determined accordingly, and no limitations are imposed here. Furthermore, it can be understood that... Figure 2The load 3 in the figure can include the power grid, which may include transmission lines, power transfer stations, communication base stations, or household appliances and other electrical equipment or power transmission equipment. The load 3 can also include motors, rectifiers, and other loads (electrical devices or power transmission devices) whose voltage and current have a non-linear relationship during operation (power supply or power consumption). In some feasible implementations, the photovoltaic inverter may include an inverter circuit 11, which converts DC power into AC power so that the output power of the photovoltaic inverter can be adapted to AC loads. In photovoltaic power supply scenarios, to ensure the efficiency of photovoltaic power supply, the photovoltaic inverter can use Maximum Power Point Tracking (MPPT) technology for power supply. That is, based on the operating state of the PV panel and the load (e.g., based on the PV panel's illumination conditions, output voltage, and other parameters, as well as the load's impedance or power consumption), the output current of the PV panel (i.e., the input current of the photovoltaic inverter) is controlled so that the PV panel operates at its maximum power point. Here, the photovoltaic inverter may include a communication circuit 12, which establishes a power line communication link with the PV panel to 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., load impedance, PV panel power generation, etc.), so that the PV panel outputs electrical energy to the load at maximum power. Meanwhile, in practical applications, the power supply side usually consists of multiple PV panels, resulting in a typically high voltage at the DC terminal of the photovoltaic inverter (i.e., the end where the photovoltaic inverter connects to the power supply). When there are issues such as aging cable connections, connector failure, model mismatch, loose connections, or when two conductors with opposite polarities are very close together and the insulation between the two wires fails, an electric arc may be generated under high voltage, endangering power supply safety. Here, the photovoltaic inverter may also include an arc detection circuit 13, which detects arcs based on noise signals between the photovoltaic inverter and the power supply. When an arc is detected in the system, the electrical connection between the photovoltaic inverter and the power supply is promptly disconnected to ensure power supply safety.

[0049] It is understandable that, while establishing a communication connection between the photovoltaic inverter and the power supply and ensuring the power supply safety of the system, in order to save design space, improve the integration of the internal circuitry of the photovoltaic inverter, and reduce design costs, the photovoltaic inverter can utilize transformer 14 to connect the communication circuit 12 and the arc detection circuit 13 together, allowing the communication circuit 12 and the arc detection circuit 13 to reuse the magnetic core in transformer 14. Please refer to the details in conjunction with... Figure 2 , Figure 2 This is a schematic diagram of a transformer provided in an embodiment of this application. Figure 2As shown, transformer 14 may include a magnetic core, at least one primary coil, and at least two secondary coils. Here, one end of at least one primary coil of transformer 14 (e.g., first primary coil S1) can be used to connect to a power source, and the other end of at least one primary coil (e.g., first primary coil S1) can be used to connect to the input terminal of inverter circuit 11. One of the at least two secondary coils of transformer 14 (e.g., first secondary coil R1) can be used to connect to communication circuit 12, and the other of the at least two secondary coils of transformer 14 (e.g., second secondary coil R2) can be used to connect to arc detection circuit 13, so that power line communication and arc detection can be simultaneously achieved based on transformer 14 including a magnetic core.

[0050] In some feasible implementations, one end of at least one primary coil of transformer 14 (e.g., the first primary coil S1) can be used to connect to the positive output terminal of the power supply, and the other end of at least one primary coil of transformer 14 (e.g., the first primary coil S1) can be used to connect to the positive input terminal of inverter circuit 11, so that when an AC signal (e.g., a noise signal or a power line communication signal) appears between the power supply and inverter circuit 11, the AC signal can be transmitted through the primary coil of transformer 14 to the secondary coil and the circuit connected to the secondary coil (e.g., a communication circuit 12 or an arc detection circuit 13).

[0051] Here, the first primary coil S1 can contain coils wound in opposite directions to suppress common-mode components in the noise signal. The parameters of the coils wound in opposite directions (e.g., number of turns, coil area, winding diameter, etc.) can be the same or different, as long as the magnetic flux generated by the common-mode components of the noise signal (or arc self-detection signal) in the positive and negative coils is equal when the noise signal (or arc self-detection signal) passes through. This can further improve the accuracy of arc detection in the system, and the method is flexible, easy to operate, and highly adaptable. This is understandable. Figure 2 The winding method and position of the coil on the magnetic core shown are merely illustrative examples. Other winding methods and positions are also applicable to this application and can be determined based on the application scenario. No restrictions are imposed here. The winding method and position of the coil on the magnetic core in the subsequent structural diagram of the transformer are also merely illustrative examples and will not be repeated hereafter.

[0052] Here, since the primary coil (e.g., the first primary coil S1) and secondary coil (e.g., the first secondary coil R1 and the second secondary coil R2) of transformer 14 are both wound on a magnetic core, communication circuit 12 and arc detection circuit 13 can transmit signals (e.g., power line communication signals and noise signals) to the primary coil of transformer 14 through their respective connected secondary coils. Here, the frequencies of the power line communication signal and the noise signal are not equal, which avoids mutual interference between the two signals. Furthermore, it can be understood that communication circuit 12 and arc detection circuit 13 can respectively change the parameters of their respective connected secondary coils (e.g., change the number of turns, coil area, or winding diameter of the first secondary coil R1 and the second secondary coil R2), causing the primary coil (e.g., the first primary coil S1) to resonate with the secondary coils connected to communication circuit 12 and arc detection circuit 13 at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by communication circuit 12 and the noise signal received by arc detection circuit 13. Meanwhile, the communication circuit 12 and the arc detection circuit 13 can also filter based on the frequency of the power line communication signal and the noise signal, respectively, to further improve the accuracy of the power line communication signal or noise signal transmission and to improve the sensitivity of the photovoltaic inverter in detecting the arc.

[0053] By adopting this application, the communication circuit and arc detection circuit can be centrally deployed in the photovoltaic inverter, which reduces the deployment space and lowers the design cost of the photovoltaic inverter while ensuring power supply safety. The structure is simple, the method is convenient, and the applicability is strong.

[0054] The following will combine Figures 3 to 9 This application provides an example illustrating the photovoltaic inverter and its working principle.

[0055] In some feasible implementations, at least one primary coil in the transformer may further include a second primary coil, and the magnetic core may include a magnetically permeable material. See also Figure 3 , Figure 3 This is a structural schematic diagram of a photovoltaic inverter provided in an embodiment of this application. Figure 3As shown, 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 can be connected to a power source, and the other end can be connected to the input terminal of the inverter circuit. The first primary coil S1 is coupled to the first secondary coil R1, and the second primary coil S2 is coupled to the second secondary coil R2. The first primary coil S1 and the first secondary coil R1 are positioned on opposite sides of the second primary coil S2 and the second secondary coil R2 within the magnetic core, separated by a magnetically conductive material. The arc detection circuit 103 can also detect arcs between the power source and the inverter circuit 101 based on the noise signal received by the second secondary coil R2 and the second primary coil S2.

[0056] Here, the primary winding of transformer 104 (e.g., the first primary winding S1 and the second primary winding S2) can be connected between inverter circuit 101 and power supply; one secondary winding (e.g., the first secondary winding R1) can be connected to communication circuit 102; and the other secondary winding (e.g., the second secondary winding R2) can be connected to arc detection circuit 103. Please refer to the details in conjunction with... Figure 4 , Figure 4 This is another structural schematic diagram of the transformer provided in an embodiment of this application. For example... Figure 4As shown, the first primary coil S1 can be coupled to the first secondary coil R1 (the first secondary coil R1 can also be positioned opposite the first primary coil S1 at the position indicated by the dashed line), and the second primary coil S2 can be coupled to the second secondary coil R2 (the second secondary coil R2 can also be positioned to the side adjacent to the second primary coil S2). Since the primary coils (e.g., the first primary coil S1 and the second primary coil S2) and the secondary coils (e.g., the first secondary coil R1 and the second secondary coil R2) of the transformer 104 are both wound on the magnetic core, the communication circuit 102 and the arc detection circuit 103 can transmit signals (e.g., power line communication signals and noise signals) to the coupled primary coils in the transformer 104 through their respective connected secondary coils. Here, the frequencies of the power line communication signal and the noise signal are not equal, which avoids mutual interference between the two signals. Therefore, it can be understood that the communication circuit 102 and the arc detection circuit 103 can respectively change the parameters of their respective connected secondary coils (e.g., change the number of turns, coil area, or winding diameter of the first secondary coil R1 and the second secondary coil R2), so that the two sets of coupled coils (e.g., the first primary coil S1 and the first secondary coil R1, the second primary coil S2 and the second secondary coil R2) 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 noise signal received by the arc detection circuit 103. Simultaneously, the communication circuit 102 and the arc detection circuit 103 can also filter based on the frequencies of the power line communication signal and the noise signal, respectively, further improving the accuracy of the power line communication signal or noise signal transmission. Here, both the first primary coil S1 and the second primary coil S2 can include coils wound in opposite directions to suppress common-mode components in the noise signal. Here, the parameters of the coils wound in opposite directions (such as the number of turns, coil area, winding diameter, etc.) can be the same or different, as long as the magnetic flux generated by the common-mode components of the noise signal (or arc self-detection signal) in the positive and negative coils is equal when the noise signal (or arc self-detection signal) passes through. This can further improve the accuracy of arc detection in the system. The method is flexible, easy to operate, and highly adaptable. In addition, the core of transformer 104 can also include a magnetically conductive material (such as... Figure 4 As shown in the shaded area, the magnetic material can divide the magnetic core into two sides to shield the signals transmitted on both sides of the magnetic core, preventing mutual interference. In other words, the two sets of coils in transformer 104 (e.g., the first primary coil S1 and the first secondary coil R1, the second primary coil S2 and the second secondary coil R2) can be arranged on both sides of the magnetic core separated by the magnetic material. The magnetic material can be ferrite, amorphous material, nanocrystalline material, or powder core material, or other materials with high permeability, offering a simple structure and strong adaptability.

[0057] In this application, the secondary coil connected to the communication circuit 102 and the arc detection circuit 103 can be coupled to the two primary coils in the transformer 104 respectively. This improves system integration and design freedom. For example, the parameters of the primary and secondary coils in each set of coupled coils can be changed, allowing for more varied resonant frequencies to adapt to the frequencies of power line communication signals and noise signals in more application scenarios. Simultaneously, each set of coupled coils can be routed and laid out separately within the photovoltaic inverter, increasing design flexibility and adaptability while maintaining higher integration.

[0058] In some feasible implementations, the photovoltaic inverter may also include an arc self-detection circuit. See details below. Figure 5 , Figure 5 This is another structural schematic diagram of the photovoltaic inverter provided in the embodiments of this application. For example... Figure 5 As shown, the photovoltaic inverter includes an inverter circuit 201, a communication circuit 202, an arc detection circuit 203, a transformer 204, and a self-test circuit 205. Here, the second secondary coil R2 can be used to connect the arc self-test circuit 205 and the arc detection circuit 203. The arc self-test circuit 205 can send an arc self-test signal based on the second secondary coil R2 and the first primary coil S1 to simulate the noise signal when an arc exists between the power supply and the inverter circuit 201. The frequency of the arc self-test signal is not equal to the frequency of the power line communication signal between the power supply and the inverter circuit 201. The arc detection circuit 203 can also receive the arc self-test 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-test circuit 205 can generate an arc self-test signal to simulate the 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. Please refer to... Figure 2 and Figure 4The arc self-test circuit 205 can be connected to the secondary coil of the transformer 204 (e.g., the second secondary coil R2). The arc self-test signal generated by the arc self-test circuit 205 can be transmitted through the second secondary coil R2 to the primary coil coupled to the second secondary coil R2 (e.g., the first primary coil S1 or the second primary coil S2). The arc detection circuit 203 then couples with this primary coil (e.g., the first primary coil S1 or the second primary coil S2) through its own connected secondary coil (e.g., the second secondary coil R2) to receive the arc self-test signal transmitted by this primary coil (e.g., the first primary coil S1 or the second primary coil S2). Here, the frequencies of the power line communication signal and the arc self-test signal are not equal, which avoids mutual interference between the two signals. Therefore, it can be understood that the communication circuit 202 and the arc self-test circuit 205 can respectively change the parameters of their connected secondary coils (e.g., change the number of turns, coil area, or winding diameter of the first secondary coil R1 and the second secondary coil R2), so that the two sets of coupled coils (e.g., the first primary coil S1 and the first secondary coil R1, the second primary coil S2 and the second secondary coil R2) resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit 202 and the arc self-test signal transmitted by the arc self-test circuit 205 received by the arc detection circuit 203. Simultaneously, the communication circuit 202 and the arc detection circuit 203 can also filter based on the frequencies of the power line communication signal and the arc self-test signal, respectively, further improving the accuracy of the power line communication signal or the arc self-test signal transmission, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0059] In some feasible implementations, such as Figure 5 When the photovoltaic inverter may include an arc self-test circuit 205, at least two secondary windings in the transformer 204 may also include a third secondary winding (such as...). Figure 5 (As shown by the dotted lines in the image). Please refer to the following for details. Figure 6 , Figure 6 This is another structural schematic diagram of the transformer provided in an embodiment of this application. For example... Figure 6 As shown, the third secondary coil R3 and the first primary coil S1 are wound around the magnetic core. The third secondary coil R3 is coupled to the first primary coil S1. The third secondary coil R3 can be connected to the arc self-test circuit 205. The arc self-test circuit 205 can send an arc self-test signal based on the third secondary coil R3 and the first primary coil S1 to simulate the noise signal when there is an arc between the power supply and the inverter circuit 201.

[0060] Here, the first primary coil S1 of transformer 204 can be connected between inverter circuit 201 and power supply; a secondary coil (e.g., first secondary coil R1) can be connected to communication circuit 202; a second secondary coil (e.g., second secondary coil R2) can be connected to arc detection circuit 203; and a third secondary coil (e.g., third secondary coil R3) can be connected to arc self-test circuit 205. Simultaneously, the first primary coil S1 can be coupled to the first secondary coil R1, the second secondary coil R2, and the third secondary coil R3. Since the primary winding (e.g., the first primary winding S1) and secondary winding (e.g., the first secondary winding R1, the second secondary winding R2, and the third secondary winding R3) of transformer 204 are both wound on a magnetic core, communication circuit 202, arc detection circuit 203, and arc self-test circuit 205 can transmit signals (e.g., power line communication signals, noise signals, and arc self-test signals) to the coupled primary winding of transformer 204 via their respective connected secondary windings. Here, the frequencies of the power line communication signal and the noise signal are not equal, and the frequencies of the power line communication signal and the arc self-test signal are also not equal, which avoids mutual interference when the two signals are transmitted simultaneously inside the photovoltaic inverter. Therefore, it can be understood that the communication circuit 202, the arc detection circuit 203, and the arc self-test circuit 205 can respectively change the parameters of their respective connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first secondary coil R1, the second secondary coil R2, and the third secondary coil R3), so that each pair 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) resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit 202, the noise signal received by the arc detection circuit 203, or the arc self-test signal received by the arc detection circuit 203. Simultaneously, the communication circuit 202 and the arc detection circuit 203 can also filter based on the frequency of the power line communication signal, the noise signal, or the arc self-test signal, further improving the accuracy of the transmission of the power line communication signal, the noise signal, or the arc self-test signal, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0061] In some feasible implementations, the primary winding of the transformer also includes a second primary winding, and the photovoltaic inverter includes an arc self-test circuit; please refer to [link to relevant documentation] for details. Figure 7 , Figure 7 This is another structural schematic diagram of the photovoltaic inverter provided in the embodiments of this application. For example... Figure 7As shown, the photovoltaic inverter includes an inverter circuit 301, a communication circuit 302, an arc detection circuit 303, a transformer 304, and an arc self-test circuit 305. At least two secondary coils in 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. 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-test circuit 305 is connected to the third secondary coil R3. The arc self-test circuit 305 can send an arc self-test signal based on the third secondary coil R3 and the second primary coil S2 to simulate noise signals when an arc exists between the power supply and the inverter circuit 301.

[0062] Here, the primary winding of transformer 304 (e.g., the first primary winding S1 or the second primary winding S2) can be connected between inverter circuit 301 and power supply; a secondary winding (e.g., the first secondary winding R1) can be connected to communication circuit 302; a second secondary winding (e.g., the second secondary winding R2) can be connected to arc detection circuit 303; and a third secondary winding (e.g., the third secondary winding R3) can be connected to arc self-test circuit 305. Please refer to the following for details. Figure 8 , Figure 8 This is another structural schematic diagram of the transformer provided in an embodiment of this application. For example... Figure 8As shown, the first primary coil S1 can be coupled to the first secondary coil R1, and the second primary coil S2 can be coupled to the second secondary coil R2 and the third secondary coil R3. Since the primary coils (e.g., the first primary coil S1 and the second primary coil S2) and the secondary coils (e.g., the first secondary coil R1, the second secondary coil R2, and the third secondary coil R3) of the transformer 304 are all wound on a magnetic core, the communication circuit 302, the arc detection circuit 303, and the arc self-test circuit 305 can transmit signals (e.g., power line communication signals, noise signals, and arc self-test signals) to the coupled primary coils in the transformer 304 via their respective connected secondary coils. Here, the frequencies of the power line communication signal and the noise signal are not equal, and the frequencies of the power line communication signal and the arc self-test signal are also not equal, which avoids mutual interference when the two signals are transmitted simultaneously inside the photovoltaic inverter. It can then be understood that the communication circuit 302, the arc detection circuit 303, and the arc self-test circuit 305 can respectively change the parameters of their respective connected secondary coils (and the primary coils coupled to each secondary coil) (e.g., changing the number of turns, coil area, or winding diameter of the first secondary coil R1, the second secondary coil R2, and the third secondary coil R3), so that each set of coupled coils (e.g., 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) resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit 302, the noise signal received by the arc detection circuit 303, or the arc self-test signal received by the arc detection circuit 303. Meanwhile, the communication circuit 302 and the arc detection circuit 303 can also filter the power line communication signal, noise signal or arc self-test signal based on their respective frequencies, further improving the accuracy of the transmission of the power line communication signal, noise signal or arc self-test signal, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0063] Furthermore, the core of transformer 304 may also include a magnetically conductive material. This material divides the core into two sides, shielding the signals transmitted on both sides of the magnetic core and preventing mutual interference. In other words, the two sets of coils in transformer 304 (e.g., 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) can be arranged on both sides of the core separated by the magnetically conductive material. This magnetically conductive material can be ferrite, amorphous materials, nanocrystalline materials, or powder cores, or other materials with high permeability, offering a simple structure and strong adaptability.

[0064] In this application, the functional modules of the photovoltaic inverter are arranged in a variety of flexible ways to adapt to different application scenarios, thereby increasing the diversity of application scenarios and enhancing the adaptability of the photovoltaic inverter. Meanwhile, the above-mentioned... Figures 1 to 8 Any of the photovoltaic inverters shown can integrate the communication circuit and arc detection circuit within the inverter itself. This ensures power supply safety while reducing installation space, lowering the design cost of the photovoltaic inverter, and offering a simple structure, convenient method, and strong applicability. For ease of description, the following will use... Figure 1 The structure of the photovoltaic inverter shown is used as an example to illustrate the drive control method provided in the embodiments of this application.

[0065] Please see Figure 9 , Figure 9 This is a flowchart illustrating the control method provided in this application. The control method provided in this application is applicable to photovoltaic inverters, including but not limited to the above-mentioned... Figures 1 to 8 Any of the photovoltaic inverters shown. For example... Figure 9 As shown, the control method provided in this application includes the following steps:

[0066] S801: Based on the power line communication signals transmitted and received by the first secondary coil and the first primary coil of the external central control system, the power line communication link between the photovoltaic inverter and the external central control system is realized.

[0067] S802: Based on the noise signal received by the second secondary coil and the first primary coil between the power supply and the inverter circuit, arc detection between the power supply and the inverter circuit is realized. The frequency of the noise signal is not equal to the frequency of the power line communication signal.

[0068] In this application, photovoltaic (PV) panels can be used as a power source connected to a load via a PV inverter. The PV inverter converts the DC power provided by the PV panels into AC power to supply the load. Here, the PV inverter may include an inverter circuit that converts DC power into AC power, ensuring the output power of the PV inverter is compatible with the AC load. In PV power supply scenarios, to ensure the efficiency of PV power supply, the PV inverter may employ MPPT (Maximum Power Point Test) technology. This means controlling the output current of the PV panels (i.e., the input current of the PV inverter) based on the operating states of the PV panels and the load (e.g., parameters such as PV panel illumination conditions, output voltage, and load impedance or power consumption), so that the PV panels operate at their maximum power point. Here, the PV inverter may include a communication circuit that establishes a power line communication link with the PV panels to control the operating current (or voltage) of the PV inverter or PV panels based on the operating states of the PV panels and the load (e.g., load impedance, PV panel power generation), enabling the PV panels to output power to the load at maximum power. Meanwhile, in practical applications, the power supply side typically consists of multiple PV panels, resulting in a generally high voltage at the DC end of the photovoltaic inverter (i.e., the end where the photovoltaic inverter connects to the power supply). When the DC end experiences issues such as aging cable connections, connector failure, model mismatch, loose connections, or when two conductors with opposite polarities are very close together and the insulation between the two wires fails, an electric arc is highly likely to occur under high voltage, jeopardizing power supply safety. Therefore, the photovoltaic inverter can also include an arc detection circuit. This circuit detects arcs based on noise signals between the photovoltaic inverter and the power supply, and promptly disconnects the electrical connection between the photovoltaic inverter and the power supply when an arc is detected, ensuring power supply safety.

[0069] It is understandable that, while establishing a communication connection between the photovoltaic inverter and the power supply and ensuring the power supply safety of the system, in order to save design space, improve the integration of the internal circuitry of the photovoltaic inverter, and reduce design costs, the photovoltaic inverter can utilize a transformer to connect the communication circuit and the arc detection circuit together, allowing the communication circuit and the arc detection circuit to reuse the magnetic core in the transformer. The transformer can include a magnetic core, at least one primary winding, and at least two secondary windings. Here, the primary winding of the transformer (e.g., the first primary winding) can be connected between the inverter circuit and the power supply, one secondary winding (e.g., the first secondary winding) can be connected to the communication circuit, and the other secondary winding (e.g., the second secondary winding) can be connected to the arc detection circuit. Since both the primary winding (e.g., the first primary winding) and the secondary windings (e.g., the first secondary winding and the second secondary winding) are wound on the magnetic core, the communication circuit and the arc detection circuit can transmit signals (e.g., power line communication signals and noise signals) with the primary winding of the transformer through their respective connected secondary windings. Here, the frequencies of the power line communication signal and the noise signal are not equal, which avoids mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), causing the primary coil (e.g., the first primary coil) to resonate at different frequencies with the secondary coils connected to the communication circuit and the arc detection circuit, 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. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the noise signal, respectively, further improving the accuracy of the power line communication signal or noise signal transmission and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0070] By adopting this application, the communication circuit and arc detection circuit can be centrally deployed in the photovoltaic inverter, which reduces the deployment space and lowers the design cost of the photovoltaic inverter while ensuring power supply safety. The structure is simple, the method is convenient, and the applicability is strong.

[0071] In some feasible implementations, at least one primary coil in the transformer may also include a second primary coil, the magnetic core may include a magnetic permeable material, and the method may also include: realizing arc detection between the power supply and the inverter circuit based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the second primary coil.

[0072] Here, the primary windings of the transformer (e.g., the first and second primary windings) can be connected between the inverter circuit and the power supply. One secondary winding (e.g., the first secondary winding) can be connected to the communication circuit, and the other secondary winding (e.g., the second secondary winding) can be connected to the arc detection circuit. Simultaneously, the first primary winding can be coupled to the first secondary winding, and the second primary winding can be coupled to the second secondary winding. Since both the primary windings (e.g., the first and second primary windings) and the secondary windings (e.g., the first and second secondary windings) are wound on a magnetic core, the communication circuit and the arc detection circuit can transmit signals (e.g., power line communication signals and noise signals) through their respective connected secondary windings and coupled primary windings in the transformer. Here, the frequencies of the power line communication signal and the noise signal are not equal, which avoids mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), so that the two sets of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) 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. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the noise signal, respectively, further improving the accuracy of the power line communication signal or noise signal transmission. In addition, the transformer core can also include a magnetically conductive material. This material can divide the core into two sides, shielding the signals transmitted on both sides of the magnetically conductive material and preventing mutual interference. In other words, the two sets of coils in the transformer (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) can be arranged on both sides of the core separated by the magnetically conductive material. The magnetic material here can be ferrite, amorphous material, nanocrystalline material, or powder core material, or other materials with high magnetic permeability. It has a simple structure and strong adaptability.

[0073] In this application, the secondary coil connected to the communication circuit and the arc detection circuit can be coupled to the two primary coils in the transformer, respectively. This improves system integration and design freedom. For example, the parameters of the primary and secondary coils in each set of coupled coils can be changed separately, allowing for more varied resonant frequencies to accommodate power line communication signals and noise signals in a wider range of applications. Furthermore, each set of coupled coils can be routed and laid out within the photovoltaic inverter, increasing design flexibility and adaptability while maintaining higher integration.

[0074] In some feasible implementations, the photovoltaic inverter may also include an arc self-test circuit, and the method may also include:

[0075] An arc self-test signal is transmitted based on the second secondary coil and the first primary coil to simulate noise signals when an arc exists between the power supply and the inverter circuit. The frequency of the arc self-test signal is not equal to the frequency of the power line communication signal. The arc self-test signal is received based on the second secondary coil to simulate arc detection between the power supply and the inverter circuit.

[0076] Here, the photovoltaic inverter may also include an arc self-test circuit. This circuit generates an arc self-test signal to simulate the noise signal generated when an arc exists at the power supply end, thereby testing the detection capability of the arc detection circuit within the photovoltaic inverter. The arc self-test circuit can be connected to the secondary coil of the transformer (e.g., the second secondary coil). The arc self-test signal generated by the circuit can be transmitted through the second secondary coil to the primary coil coupled to it (e.g., the first or second primary coil). The arc detection circuit then couples with this primary coil (e.g., the first or second primary coil) through its connected secondary coil (e.g., the second secondary coil) to receive the arc self-test signal transmitted by this primary coil (e.g., the first or second primary coil). Here, the power line communication signal and the arc self-test signal have different frequencies to avoid mutual interference between the two signals. Furthermore, it can be understood that the communication circuit and the arc self-detection circuit can respectively change the parameters of their connected secondary coils (e.g., changing the number of turns, coil area, or winding diameter of the first and second secondary coils), causing the two sets of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil) to resonate at different frequencies. This increases the signal strength of the power line communication signal transmitted and received by the communication circuit and the arc self-detection signal received by the arc detection circuit from the arc self-detection circuit. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequencies of the power line communication signal and the arc self-detection signal, respectively, further improving the accuracy of the power line communication signal or the arc self-detection signal transmission, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs.

[0077] In some feasible implementations, when the photovoltaic inverter may include an arc self-test circuit, at least two secondary coils in the transformer may further include a third secondary coil, and the method may further include the following before receiving the arc self-test signal based on the second secondary coil:

[0078] An arc self-test signal is sent based on the third secondary coil and the first primary coil to simulate the noise signal when there is an arc between the power supply and the inverter circuit.

[0079] Here, the primary winding of the transformer (e.g., a first primary winding or a second primary winding) can be connected between the inverter circuit and the power supply. A secondary winding (e.g., a first secondary winding) can be connected to a communication circuit, a second secondary winding (e.g., a second secondary winding) can be connected to an arc detection circuit, and a third secondary winding (e.g., a third secondary winding) can be connected to an arc self-detection circuit. Simultaneously, the first primary winding can be coupled to the first secondary winding, and the second primary winding can be coupled to the second and third secondary windings. When the inverter includes only one primary winding, the first primary winding can be coupled to the first, second, and third secondary windings. Since the primary windings (e.g., the first and second primary windings) and secondary windings (e.g., the first, second, and third secondary windings) of the transformer are all wound on a magnetic core, the communication circuit, the arc detection circuit, and the arc self-test circuit can transmit signals (e.g., power line communication signals, noise signals, and arc self-test signals) to the coupled primary windings in the transformer via their respective connected secondary windings. Here, the frequencies of the power line communication signal and the noise signal are not equal, and the frequencies of the power line communication signal and the arc self-test signal are also not equal, which avoids mutual interference when the two signals are transmitted simultaneously inside the photovoltaic inverter. Furthermore, it can be understood that the communication circuit, arc detection circuit, and arc self-test circuit can respectively change the parameters of their connected secondary coils (and the primary coils coupled to each secondary coil) (e.g., changing the number of turns, coil area, or winding diameter of the first, second, and third secondary coils), so that each pair of coupled coils (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil, and the third secondary coil; or the first primary coil and the first secondary coil, the second secondary coil, and the third secondary coil) resonate at different frequencies, thereby increasing the signal strength of the power line communication signal transmitted and received by the communication circuit, the noise signal received by the arc detection circuit, or the arc self-test signal received by the arc detection circuit. Simultaneously, the communication circuit and the arc detection circuit can also filter based on the frequency of the power line communication signal, the noise signal, or the arc self-test signal, further improving the accuracy of the transmission of the power line communication signal, the noise signal, or the arc self-test signal, and enhancing the sensitivity of the photovoltaic inverter in detecting arcs. Furthermore, the transformer core may also include a magnetically conductive material. This material divides the core into two sides, shielding the signals transmitted on both sides and preventing mutual interference. In other words, the two sets of coils in the transformer (e.g., the first primary coil and the first secondary coil, the second primary coil and the second secondary coil, and the third secondary coil) can be arranged on either side of the core separated by the magnetically conductive material. This magnetically conductive material can be ferrite, amorphous materials, nanocrystalline materials, or powder cores, or other materials with high permeability, offering a simple structure and strong adaptability.

[0080] In some feasible implementations, arc detection between the power supply and the inverter circuit is achieved based on the noise signal received between the power supply and the inverter circuit by the second secondary coil and the first primary coil, which may include:

[0081] When the amplitude of the noise signal is greater than or equal to the first noise threshold, an electric arc is detected between the power supply and the inverter circuit. When the amplitude of the noise signal is less than the second noise threshold, no electric arc is detected between the power supply and the inverter circuit, and the second noise threshold is less than or equal to the first noise threshold.

[0082] It is understood that the value of the first noise threshold (and / or the second noise threshold) here can be determined based on the amplitude of the noise signal when an electric arc occurs in the system, or it can be determined based on the first noise threshold (and / or the second noise threshold) obtained by the photovoltaic inverter through acquisition, collection, reception, detection, or storage. For example, the photovoltaic inverter or the external central control system can calculate the amplitude of the noise signal generated when the photovoltaic system is working normally (without an electric arc) within a certain noise signal amplitude range during the operation of the photovoltaic inverter (or during the design process). Then, the arc detection circuit can obtain the first noise threshold (and / or the second noise threshold) based on this relationship curve, which can be set according to the application scenario. It is understood that the first noise threshold (and / or the second noise threshold) here can be a voltage value (or a current value or a power value), can be multiple discrete voltage values ​​(or current values ​​or power values), can be a voltage range (or current range or power range) composed of multiple discrete voltage values ​​(or current values ​​or power values) or continuous voltage values ​​(or current values ​​or power values). Meanwhile, the second noise threshold can 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 can avoid mistakenly determining that the arc in the system has disappeared (or that the arc does not exist) when the amplitude of the noise signal is occasionally less than the first noise threshold after detecting the occurrence of an arc. Furthermore, the arc detection circuit can avoid frequently switching the connection between the photovoltaic inverter and the power supply, or avoid failing to switch the connection between the photovoltaic inverter and the power supply in time due to misjudgment when an arc occurs, thus further improving the safety of the system power supply.

[0083] In some feasible implementations, arc detection between the power supply and the inverter circuit is achieved based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the first primary coil, and may further include:

[0084] The noise signal is sampled at least once, and the amplitude of the noise signal is obtained based on the result of the at least once sampling.

[0085] Here, the arc detection circuit can sample the received noise signal at the same sampling point (or multiple different sampling points) within a continuous time period (or at multiple time points with a certain time interval), and directly (or average, or after weighted averaging) calculate the amplitude of the noise signal from the sampled results, or perform calculations such as discrete Fourier transform or wavelet transform on the sampled results to obtain the amplitude of the noise signal, thereby further improving the arc detection accuracy and precision of the system.

[0086] In this application, the photovoltaic inverter can integrate the communication circuit and the arc detection circuit into the inverter, which reduces the installation space and lowers the design cost of the photovoltaic inverter while ensuring power supply safety. The structure is simple, the method is convenient, and the applicability is strong.

[0087] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A photovoltaic inverter, characterized in that, 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, with the at least one primary coil and the at least two secondary coils wound around the magnetic core. One end of the first primary coil in at least one primary coil of the transformer is used to connect to the power supply, and the other end of the first primary coil is used to connect to the input terminal of the inverter circuit. The first secondary coil in at least two secondary coils of the transformer is used to connect to the communication circuit, and the second secondary coil in at least two secondary coils of the transformer is used to connect to the arc detection circuit, so as to realize both power line communication and arc detection based on the transformer including a magnetic core. The communication circuit is used to transmit and receive power line communication signals with the first primary coil via the first secondary coil. The arc detection circuit is used to receive noise signals between the power supply and the inverter circuit through the second secondary coil and the first primary coil, wherein the frequency of the power line communication signal and the frequency of the noise signal are not equal.

2. The photovoltaic inverter according to claim 1, characterized in that, One end of the first primary coil is used to connect to the positive output terminal of the power supply, and the other end of the first primary coil is used to connect to the positive input terminal of the inverter circuit.

3. The photovoltaic inverter according to claim 1, characterized in that, At least one primary coil in the transformer also includes a second primary coil. The magnetic core includes a magnetically conductive material. One end of the second primary coil is used to connect to the power supply, and the other end of the second primary coil is used to connect to the input terminal of the inverter circuit. The first primary coil is coupled to the first secondary coil, and the second primary coil is coupled to the second secondary coil. The first primary coil and the first secondary coil are arranged on both sides of the magnetic core separated by the magnetically conductive material. The arc detection circuit is also used to detect the arc between the power supply and the inverter circuit based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the second primary coil.

4. The photovoltaic inverter according to any one of claims 1-3, characterized in that, The photovoltaic inverter also includes an arc self-testing circuit, and the second secondary coil is used to connect the arc self-testing circuit and the arc detection circuit. The arc self-test circuit is used to send an arc self-test signal to the arc detection circuit based on the second secondary coil and the first primary coil, so as to simulate the noise signal when there is an arc between the power supply and the inverter circuit through the arc self-test signal. The frequency of the arc self-test signal is not equal to the frequency of the power line communication signal between the power supply and the inverter circuit. The arc detection circuit is also used to receive the arc self-test signal based on the second secondary coil, simulating arc detection between the power supply and the inverter circuit.

5. The photovoltaic inverter according to claim 4, characterized in that, When the photovoltaic inverter includes an arc self-test circuit, at least two secondary coils in the transformer also 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. The third secondary coil is used to connect to the arc self-test circuit. The arc self-test circuit is used to send the arc self-test signal to the arc detection circuit based on the third secondary coil and the first primary coil, so as to simulate the noise signal when there is an arc between the power supply and the inverter circuit through the arc self-test signal.

6. The photovoltaic inverter according to claim 5, characterized in that, Both the first primary coil and the second primary coil have coils wound in opposite directions to suppress common-mode components in the noise signal.

7. The photovoltaic inverter according to any one of claims 1-3, characterized in that, The arc detection circuit is also used to detect an arc between the power supply and the inverter circuit when the amplitude of the noise signal is greater than or equal to a first noise threshold. The arc detection circuit is further configured to detect that there is no arc between the power supply and the inverter circuit when the amplitude of the noise signal is less than a second noise threshold, wherein the second noise threshold is less than or equal to the first noise threshold.

8. The photovoltaic inverter according to claim 7, characterized in that, The arc detection circuit is also used to sample the noise signal at least once, and to obtain the amplitude of the noise signal based on the result of sampling the noise signal at least once.

9. A control method for a photovoltaic inverter, characterized in that, The control method is applicable to a photovoltaic inverter, which 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, wherein the at least one primary coil and the at least two secondary coils are wound around the magnetic core. One end of the first primary coil of at least one primary winding of the transformer is used to connect to a power source, and the other end of the first primary coil is used to connect to the input terminal of the inverter circuit. The first secondary coil of at least two secondary windings of the transformer is used to connect to the communication circuit, and the second secondary coil of at least two secondary windings of the transformer is used to connect to the arc detection circuit. The method includes: The power line communication link between the photovoltaic inverter and the external central control system is realized based on the power line communication signals transmitted and received by the first secondary coil and the first primary coil. Arc detection between the power supply and the inverter circuit is achieved based on the noise signal received by the second secondary coil and the first primary coil. The frequency of the noise signal is not equal to the frequency of the power line communication signal.

10. The control method according to claim 9, characterized in that, At least one primary coil in the transformer further includes a second primary coil. The magnetic core includes a magnetically conductive material. One end of the second primary coil is used to connect to the power supply, and the other end of the second primary coil is used to connect to the input terminal of the inverter circuit. The first primary coil is coupled to the first secondary coil, and the second primary coil is coupled to the second secondary coil. The first primary coil and the first secondary coil are arranged on both sides of the magnetic core separated by the magnetically conductive material. The method further includes: Based on the noise signal received by the second secondary coil and the second primary coil between the power supply and the inverter circuit, arc detection between the power supply and the inverter circuit is achieved.

11. The control method according to claim 9 or 10, characterized in that, The photovoltaic inverter further includes an arc self-test circuit, and the second secondary coil is used to connect the arc self-test circuit and the arc detection circuit. The method further includes: Based on the second secondary coil and the first primary coil, an arc self-test signal is sent to the arc detection circuit to simulate the noise signal when there is an arc between the power supply and the inverter circuit. The frequency of the arc self-test signal is not equal to the frequency of the power line communication signal. The second secondary coil receives the arc self-test signal to simulate arc detection between the power supply and the inverter circuit.

12. The control method according to claim 11, characterized in that, When the photovoltaic inverter includes an arc self-test circuit, at least two secondary coils in the transformer also 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. The third secondary coil is used to connect to the arc self-test circuit. Before receiving the arc self-test signal based on the second secondary coil, the method further includes: The arc self-test signal is sent to the arc detection circuit based on the third secondary coil and the first primary coil, so as to simulate the noise signal when there is an arc between the power supply and the inverter circuit.

13. The control method according to claim 9 or 10, characterized in that, The method of detecting arc between the power supply and the inverter circuit based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the first primary coil includes: When the amplitude of the noise signal is greater than or equal to the first noise threshold, an electric arc is detected between the power supply and the inverter circuit. When the amplitude of the noise signal is less than the second noise threshold, an electric arc is detected between the power supply and the inverter circuit, and the second noise threshold is less than or equal to the first noise threshold.

14. The control method according to claim 13, characterized in that, The method of detecting arc between the power supply and the inverter circuit based on the noise signal between the power supply and the inverter circuit received by the second secondary coil and the first primary coil further includes: The noise signal is sampled at least once, and the amplitude of the noise signal is obtained based on the result of the at least one sampling of the noise signal.

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