Power line carrier communication circuit and photovoltaic grid-connected inverter system

Abstract

The utility model provides an electric power carrier wave communication circuit and a photovoltaic grid-connected inverter system, the electric power carrier wave communication circuit can be arranged in a corresponding module in the photovoltaic grid-connected inverter system, and the electric power carrier wave communication circuit comprises a coupling circuit, a carrier wave sending circuit, a carrier wave receiving circuit and a processor, the processor sends a broadband communication signal or a narrowband communication signal through the carrier wave sending circuit and carries out coupling sending with a power supply signal through the coupling circuit, and the processor controls the carrier wave receiving circuit to be switched to a broadband receiving state or a narrowband receiving state by outputting a switching control signal; and a broadband communication signal or a narrowband communication signal is correspondingly received, so that different communication switching is realized when different communication requirements are met, the communication reliability is improved, and the communication requirements are met.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of power line carrier communication, especially relates to a power line carrier communication circuit and photovoltaic grid-connected inverter system. BACKGROUND

[0002] As a new type of clean energy, photovoltaic power generation is paid more and more attention by all countries in the world, and in recent years, it has formed a market trend of increasing year by year.

[0003] The ground photovoltaic power station composed of photovoltaic grid-connected inverters has many devices of various types, and the communication scheme between the devices is often realized through RS485 serial communication bus technology, which is stable and has no signal interference, but requires laying communication cables, increasing material and construction costs, and once a communication fault occurs, it is difficult to locate the communication fault point. In order to solve the related problems, power line carrier communication technology is applied in photovoltaic power stations, which realizes carrier communication by carrying communication signals on power lines, improving the convenience and maintainability of power station communication.

[0004] Among them, the inverter equipment of the ground photovoltaic power station adopts power line carrier communication mode through AC cable lines to realize data communication with the sampling equipment in the booster station, but the laying range caused by the system capacity or terrain of the ground power station often exceeds the effective distance of power line carrier communication, resulting in poor communication or no communication of individual inverter equipment, and the communication reliability is low. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a power line carrier communication circuit, which aims at solving the problem of low communication reliability of the traditional power line carrier communication mode.

[0006] The first aspect of the utility model embodiment proposes a power line carrier communication circuit, which comprises:

[0007] The coupling circuit is connected with the power line, and is used for realizing coupling carrier or decoupling of the communication signal and the power signal on the power line;

[0008] The carrier sending circuit is connected with the coupling circuit, and is used for sending a wideband communication signal or a narrowband communication signal to the coupling circuit, wherein the communication frequency of the wideband communication signal is greater than that of the narrowband communication signal;

[0009] The carrier receiving circuit is connected with the coupling circuit, and is triggered to turn on a first transmission channel and receive the wideband communication signal output by the coupling circuit under the action of a first switching control signal, or is triggered to turn on a second transmission channel and receive the narrowband communication signal output by the coupling circuit under the action of a second switching control signal;

[0010] a processor connected with the carrier transmitting circuit and the carrier receiving circuit respectively, the processor transceiving the wideband communication signal or the narrowband communication signal, and outputting the first switching control signal or the second switching control signal.

[0011] Optionally, the coupling circuit comprises a coupler connected with the carrier transmitting circuit, the carrier receiving circuit and the power line respectively.

[0012] Optionally, the carrier transmitting circuit comprises a power amplifier, the input end and the output end of the power amplifier constituting the input end and the output end of the carrier transmitting circuit respectively.

[0013] Optionally, the carrier receiving circuit comprises:

[0014] a wideband receiving circuit connected with the coupling circuit, for receiving the wideband communication signal;

[0015] a narrowband receiving circuit connected with the coupling circuit, for receiving the narrowband communication signal;

[0016] a switching circuit connected with the wideband receiving circuit, the narrowband receiving circuit and the processor respectively, the switching circuit being triggered to turn on a first transmission channel and transmit the wideband communication signal by the first switching control signal, or being triggered to turn on a second transmission channel and transmit the narrowband communication signal by the second switching control signal.

[0017] Optionally, the wideband receiving circuit comprises a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a first inductor, a second inductor, a third inductor and a first resistor;

[0018] the first end of the first capacitor and the first end of the second capacitor constituting a signal input end of the wideband receiving circuit, the second end of the first capacitor, the first end of the third capacitor and the first end of the first inductor being connected, the second end of the second capacitor, the first end of the fourth capacitor and the second end of the first inductor being connected, the second end of the third capacitor, the first end of the fifth capacitor and the first end of the second inductor being connected, the second end of the fourth capacitor, the second end of the fifth capacitor and the first end of the third inductor being connected, the second end of the second inductor, the first end of the sixth capacitor and the first end of the seventh capacitor being connected, the second end of the third inductor, the second end of the sixth capacitor and the first end of the eighth capacitor being connected, the second end of the seventh capacitor and the first end of the first resistor being connected, the second end of the eighth capacitor and the second end of the first resistor being connected, and the two ends of the first resistor constituting a signal output end of the wideband receiving circuit.

[0019] Optionally, the narrowband receiving circuit comprises a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourth inductor and a fifth inductor;

[0020] The first end of the second resistor and the first end of the third resistor constitute a signal input end of the narrowband receiving circuit, the second end of the second resistor, the first end of the ninth capacitor, the first end of the fourth inductor and the first end of the fourth resistor are connected, the second end of the third resistor, the second end of the ninth capacitor, the second end of the fourth inductor and the first end of the fifth resistor are connected, the second end of the fourth resistor, the first end of the fifth inductor, the first end of the tenth capacitor, the first end of the twelfth capacitor and the first end of the sixth resistor are connected, the second end of the fifth resistor, the second end of the fifth inductor, the first end of the eleventh capacitor, the first end of the thirteenth capacitor and the second end of the sixth resistor are connected, the second end of the tenth capacitor and the second end of the eleventh capacitor are grounded, and the second end of the twelfth capacitor and the second end of the thirteenth capacitor constitute a signal output end of the narrowband receiving circuit.

[0021] Optionally, the switching circuit comprises:

[0022] a first switch circuit connected between the wideband receiving circuit and the processor, the first switch circuit being triggered to be turned on and transmit the wideband communication signal by the first switching control signal and being triggered to be turned off by the second switching control signal;

[0023] a second switch circuit connected between the narrowband receiving circuit and the processor, the second switch circuit being triggered to be turned on and transmit the narrowband communication signal by the second switching control signal and being triggered to be turned off by the first switching control signal.

[0024] Optionally, the carrier receiving circuit comprises:

[0025] a wideband receiving circuit connected with the coupling circuit and the processor respectively, the wideband receiving circuit being triggered to be turned on and transmit the wideband communication signal by the first switching control signal and being triggered to be turned off by the second switching control signal;

[0026] a narrowband receiving circuit connected with the coupling circuit and the processor respectively, the narrowband receiving circuit being triggered to be turned on and transmit the narrowband communication signal by the second switching control signal and being triggered to be turned off by the first switching control signal.

[0027] Optionally, the wideband receiving circuit comprises a wideband filter circuit and a third switch circuit connected in series between the coupling circuit and the processor;

[0028] the wideband filter circuit, configured to filter and output the wideband communication signal;

[0029] the third switch circuit, further connected with the processor, triggered to turn on by the first switching control signal and triggered to turn off by the second switching control signal.

[0030] Optionally, the wideband filter circuit comprises a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor, an eighteenth capacitor, a nineteenth capacitor, a twentieth capacitor, a twenty-first capacitor, a sixth inductor, a seventh inductor, an eighth inductor and a seventh resistor;

[0031] a first end of the fourteenth capacitor and a first end of the fifteenth capacitor constitute a signal input end of the wideband filter circuit, a second end of the fourteenth capacitor, a first end of the sixteenth capacitor and a first end of the sixth inductor are connected, a second end of the fifteenth capacitor, a first end of the seventeenth capacitor and a second end of the sixth inductor are connected, a second end of the sixteenth capacitor, a first end of the eighteenth capacitor and a first end of the seventh inductor are connected, a second end of the seventeenth capacitor, a second end of the eighteenth capacitor and a first end of the eighth inductor are connected, a second end of the seventh inductor, a first end of the nineteenth capacitor and a first end of the twentieth capacitor are connected, a second end of the eighth inductor, a second end of the nineteenth capacitor and a first end of the twenty-first capacitor are connected, a second end of the twentieth capacitor is connected with a first end of the seventh resistor, a second end of the twenty-first capacitor is connected with a second end of the seventh resistor, and two ends of the seventh resistor constitute a signal output end of the wideband filter circuit.

[0032] Optionally, the narrowband receiving circuit comprises a narrowband filter circuit and a fourth switch circuit connected in series between the coupling circuit and the processor;

[0033] the narrowband filter circuit, configured to filter and output the narrowband communication signal;

[0034] the fourth switch circuit, further connected with the processor, triggered to turn on by the second switching control signal and triggered to turn off by the first switching control signal.

[0035] Optionally, the narrowband filter circuit comprises an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a twenty-second capacitor, a twenty-third capacitor, a twenty-fourth capacitor, a twenty-fifth capacitor, a twenty-sixth capacitor, a ninth inductor and a tenth inductor;

[0036] The first end of the eighth resistor and the first end of the ninth resistor constitute a signal input end of the narrowband filter circuit, the second end of the eighth resistor, the first end of the twenty-second capacitor, the first end of the ninth inductor and the first end of the tenth resistor are connected, the second end of the ninth resistor, the second end of the twenty-second capacitor, the second end of the ninth inductor and the first end of the eleventh resistor are connected, the second end of the tenth resistor, the first end of the tenth inductor, the first end of the twenty-third capacitor, the first end of the twenty-fifth capacitor and the first end of the twelfth resistor are connected, the second end of the eleventh resistor, the second end of the tenth inductor, the first end of the twenty-fourth capacitor, the first end of the twenty-sixth capacitor and the second end of the twelfth resistor are connected, the second end of the twenty-third capacitor and the second end of the twenty-fourth capacitor are grounded, and the second end of the twenty-fifth capacitor and the second end of the twenty-sixth capacitor constitute a signal output end of the narrowband filter circuit.

[0037] The second aspect of the embodiment of the utility model provides a photovoltaic grid-connected inverter system, including a plurality of power carrier communication circuit as described above.

[0038] The beneficial effect of the embodiment of the utility model compared with prior art is: the power carrier communication circuit can be arranged in the corresponding module in the photovoltaic grid-connected inverter system, the power carrier communication circuit includes coupling circuit, carrier sending circuit, carrier receiving circuit and processor, the processor sends wideband communication signal or narrowband communication signal through carrier sending circuit and sends through coupling circuit with power signal coupling, and the processor controls carrier receiving circuit to switch to wideband receiving state or narrowband receiving state through output switching control signal, and corresponding receiving wideband communication signal or narrowband communication signal, to realize different communication switching when different communication requirements, improve communication reliability and meet the communication requirements. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description, and obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0040] Figure 1 The first kind of structure schematic view of the power carrier communication circuit provided by the utility model embodiment;

[0041] Figure 2 The second kind of structure schematic view of the power carrier communication circuit provided by the utility model embodiment;

[0042] Figure 3The first circuit schematic diagram of the power carrier communication circuit is provided for the embodiment of the utility model.

[0043] Figure 4 The third structure schematic diagram of the power carrier communication circuit is provided for the embodiment of the utility model.

[0044] Figure 5 The fourth structure schematic diagram of the power carrier communication circuit is provided for the embodiment of the utility model.

[0045] Figure 6 The second circuit schematic diagram of the power carrier communication circuit is provided for the embodiment of the utility model. DETAILED DESCRIPTION

[0046] In order to make the technical problems, technical solutions and beneficial effects to be solved by the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and embodiments.

[0047] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "multiple" is two or more than two, unless otherwise specifically limited.

[0048] The first aspect of the embodiment of the utility model proposes a power carrier communication circuit 100.

[0049] Among them, the power carrier communication circuit 100 can be correspondingly arranged in the corresponding module of the photovoltaic grid-connected inverter system, for example, arranged in the inverter equipment and the boost station data acquisition equipment respectively, the inverter equipment carries out data communication with the boost station data acquisition equipment through the power carrier communication circuit 100 of itself, the power line and the power carrier communication circuit 100 in the boost station data acquisition equipment.

[0050] Among them, in order to meet different communication needs and improve communication reliability, in an optional embodiment, as shown in Figure 1 The power carrier communication circuit 100 includes:

[0051] The coupling circuit 10 is connected with the power line, the coupling circuit 10 is used for realizing coupling carrier or decoupling of the communication signal and the power signal on the power line;

[0052] The carrier transmitting circuit 20 is connected with the coupling circuit 10, and the carrier transmitting circuit 20 is used for transmitting a wideband communication signal or a narrowband communication signal to the coupling circuit 10, wherein the communication frequency of the wideband communication signal is greater than the communication frequency of the narrowband communication signal;

[0053] The carrier receiving circuit 30 is connected with the coupling circuit 10, and the carrier receiving circuit 30 is triggered to turn on the first transmission channel and receive the wideband communication signal output by the coupling circuit 10 under the first switching control signal, or is triggered to turn on the second transmission channel and receive the narrowband communication signal output by the coupling circuit 10 under the second switching control signal;

[0054] The processor 40 is connected with the carrier transmitting circuit 20 and the carrier receiving circuit 30 respectively, and the processor 40 transmits and receives the wideband communication signal or the narrowband communication signal, and outputs the first switching control signal or the second switching control signal.

[0055] In the embodiment, the corresponding modules of the photovoltaic grid-connected inverter system are connected with power lines, and the power supply signals are transmitted between the modules through the power lines. For example, the inverter of the inverter device and the transformer of the booster station device are connected with the power lines, a plurality of photovoltaic components generate alternating current power through the inverter device respectively, and the alternating current power is output to the transformer of the transformer device through the combiner box, and is boosted by the transformer and output to the power grid.

[0056] The power carrier communication circuit 100 is arranged in the corresponding module respectively, and communication is performed through the power carrier communication circuit 100 to perform data interaction, instruction transmission and the like. The power carrier communication circuit 100 couples or decouples signals through the coupling circuit 10 to couple the communication signals to the power lines or decouple the communication signals from the power lines.

[0057] When the power carrier communication circuit 100 works normally, one of wideband communication or narrowband communication can be selected as the communication mode. The wideband communication has the characteristics of high communication frequency, fast transmission rate but short communication distance, and the narrowband communication has the characteristics of low communication frequency, slow transmission rate but long communication distance.

[0058] The carrier receiving circuit 30 has the first transmission channel and the second transmission channel inside. The first transmission channel can pass the wideband communication signal and cut off the transmission of the narrowband communication signal, and the second transmission channel can pass the narrowband communication signal and cut off the transmission of the wideband communication signal. The carrier receiving circuit 30 can be switched to different transmission channels and work in the transmission of signals with different bandwidths based on the received switching control signal.

[0059] In an optional embodiment, the power carrier communication circuit 100 normally works in a broadband communication mode, and the processor 40 of each module of the power carrier communication circuit 100 outputs a first switching control signal to the carrier receiving circuit 30 of each power carrier communication circuit 100 based on a trigger instruction or a trigger action, and each carrier receiving circuit 30 triggers to turn on the first transmission channel in itself.

[0060] Taking two modules in a photovoltaic grid-connected inverter system as an example, the power carrier communication circuit 100 of each module is a first power carrier communication circuit and a second power carrier communication circuit.

[0061] In normal communication work, the processor 40 of the first power carrier communication circuit sends a broadband communication signal, and sends it to the coupling circuit 10 through the carrier sending circuit 20. The carrier sending circuit 20 can perform signal processing on the broadband communication signal, such as signal amplification, filtering, etc. The coupling circuit 10 couples the broadband communication signal to the power signal on the power line, and the broadband communication signal is transmitted to the coupling circuit 10 of the second power carrier communication circuit through the power line carrier, and the coupling circuit 10 of the second power carrier communication circuit decouples the broadband communication signal from the power line, and transmits it to the processor 40 of the second power carrier communication circuit through the first transmission channel in the carrier receiving circuit 30 of the second power carrier communication circuit.

[0062] Similarly, after receiving the broadband communication signal, the processor 40 of the second power carrier communication circuit performs data interaction and feedback, sends the broadband communication signal to the coupling circuit 10 through the carrier sending circuit 20, and the coupling circuit 10 couples the broadband communication signal to the power signal on the power line. The broadband communication signal is transmitted to the coupling circuit 10 of the first power carrier communication circuit through the power line carrier, and the coupling circuit 10 of the first power carrier communication circuit decouples the broadband communication signal from the power line, and transmits it to the processor 40 of the first power carrier communication circuit through the first transmission channel in the carrier receiving circuit 30 of the first power carrier communication circuit. Thus, the transmission of the broadband communication signal between the two power carrier communication circuits 100 and between the two modules is completed, and the purpose of high communication frequency and fast transmission rate can be achieved.

[0063] When the photovoltaic grid-connected inverter system finds that the distance between the two modules is far during installation or debugging, or finds that the broadband communication signal has frequency band interference and the communication effect is poor during use, a trigger instruction can be output to the processor 40 through a man-machine interface or preset parameters in the background, and the processor 40 outputs a second switching control signal to each carrier receiving circuit 30, and each carrier receiving circuit 30 triggers to turn on the second transmission channel in itself.

[0064] When data communication is carried out through narrowband communication signals, taking two modules in a photovoltaic grid-connected inverter system as an example, the power carrier communication circuit 100 of the two modules is respectively a first power carrier communication circuit and a second power carrier communication circuit.

[0065] The processor 40 of the first power carrier communication circuit sends the narrowband communication signals to the coupling circuit 10 through the carrier sending circuit 20, and the carrier sending circuit 20 can perform signal processing on the narrowband communication signals, such as signal amplification, filtering, etc., the coupling circuit 10 couples the narrowband communication signals to the power supply signals on the power line, the narrowband communication signals are transmitted to the coupling circuit 10 of the second power carrier communication circuit through the power line carrier, the coupling circuit 10 of the second power carrier communication circuit decouples the narrowband communication signals from the power line, and transmits them to the processor 40 of the second power carrier communication circuit through the second transmission channel inside the carrier receiving circuit 30 of the second power carrier communication circuit.

[0066] Similarly, after receiving the narrowband communication signals, the processor 40 of the second power carrier communication circuit carries out data interaction and feedback, sends the narrowband communication signals to the coupling circuit 10 through the carrier sending circuit 20, the coupling circuit 10 couples the narrowband communication signals to the power supply signals on the power line, the narrowband communication signals are transmitted to the coupling circuit 10 of the first power carrier communication circuit through the power line carrier, the coupling circuit 10 of the first power carrier communication circuit decouples the narrowband communication signals from the power line, and transmits them to the processor 40 of the first power carrier communication circuit through the second transmission channel inside the carrier receiving circuit 30 of the first power carrier communication circuit, thereby completing the transmission of the narrowband communication signals between the two power carrier communication circuits 100 and the two modules, the narrowband communication signals work in a lower communication frequency band, reduce frequency band interference, and can achieve a longer communication distance, meet the communication coverage requirements of the photovoltaic grid-connected inverter system, and improve the communication reliability.

[0067] The coupling circuit 10 can adopt a corresponding coupling structure, in an optional embodiment, the coupling circuit 10 includes a coupler, which is connected with the carrier sending circuit 20, the carrier receiving circuit 30 and the power line respectively, and realizes the coupling and decoupling of the communication signals, wherein the coupler can adopt a corresponding coupling capacitor, coupling transformer or other structure.

[0068] The carrier transmitting circuit 20 is configured to transmit the wideband communication signal and the narrowband communication signal, and to perform corresponding signal processing on the communication signal. In an optional embodiment, in order to meet the power requirement of the power carrier, the carrier transmitting circuit 20 comprises a power amplifier, an input end and an output end of the power amplifier constitute an input end and an output end of the carrier transmitting circuit 20 respectively, and the power amplifier is configured to perform power amplification on the output wideband communication signal or narrowband communication signal, so as to meet the power requirement of the communication signal transmitted on the power line, avoid the communication signal from being unable to be normally transmitted and received due to too small signal power, and improve the communication reliability.

[0069] The first transmission channel and the second transmission channel in the carrier receiving circuit 30 can be provided with corresponding bandwidth filter circuits, so as to perform bandwidth filtering on the communication signal transmitted by the coupling circuit 10, and thus obtain and output the communication signal with a corresponding bandwidth to the processor 40.

[0070] In an optional embodiment, as shown in Figure 2 The carrier receiving circuit 30 comprises:

[0071] a wideband receiving circuit 31 connected with the coupling circuit 10 and configured to receive the wideband communication signal;

[0072] a narrowband receiving circuit 32 connected with the coupling circuit 10 and configured to receive the narrowband communication signal;

[0073] a switching circuit 33 connected with the wideband receiving circuit 31, the narrowband receiving circuit 32 and the processor 40 respectively, the switching circuit 33 is triggered to turn on the first transmission channel and transmit the wideband communication signal based on the first switching control signal, or is triggered to turn on the second transmission channel and transmit the narrowband communication signal based on the second switching control signal.

[0074] In the embodiment, the switching circuit 33 has a first signal input end, a second signal input end and a signal output end, the first signal input end and the second signal input end are connected with the signal output end of the wideband receiving circuit 31 and the signal output end of the narrowband receiving circuit 32 respectively, and the signal output end of the switching circuit 33 is connected with the signal input end of the processor 40, the switching circuit 33 is triggered to connect the first signal input end and the signal output end based on the first switching control signal, so as to connect the processor 40 and the wideband receiving circuit 31, or the switching circuit 33 is triggered to connect the second signal input end and the signal output end based on the second switching control signal, so as to connect the processor 40 and the narrowband receiving circuit 32.

[0075] In normal operation, the processor 40 outputs a first switching control signal to the switching circuit 33, the switching circuit 33 switches the connection between the wideband receiving circuit 31 and the processor 40, the wideband receiving circuit 31 obtains the wideband communication signal from the coupling circuit 10 and transmits it to the processor 40 through the switching circuit 33, so as to achieve high communication frequency and fast transmission rate.

[0076] When the photovoltaic grid-connected inverter system finds that the distance between two modules is far away during installation or debugging, or finds that the wideband communication signal has frequency band interference and the communication effect is poor during use, the processor 40 outputs a second switching control signal to the switching circuit 33, the switching circuit 33 switches the connection between the narrowband receiving circuit 32 and the processor 40, the narrowband receiving circuit 32 obtains the narrowband communication signal from the coupling circuit 10 and transmits it to the processor 40 through the switching circuit 33, the narrowband communication signal works in a lower communication frequency band, reduces the frequency band interference, and can achieve a longer communication distance, meet the communication coverage requirements of the photovoltaic grid-connected inverter system, and improve the communication reliability.

[0077] Among them, the wideband receiving circuit 31 and the narrowband receiving circuit 32 can adopt corresponding signal processing circuits, such as filter, amplifier and other circuit structures, in order to receive reliable wideband communication signals and avoid interference from other frequency band communication signals or noise signals, in an optional embodiment, as shown in Figure 3 The wideband receiving circuit 31 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a first inductor L1, a second inductor L2, a third inductor L3 and a first resistor R1.

[0078] The first end of the first capacitor C1 and the first end of the second capacitor C2 constitute the signal input end of the wideband receiving circuit 31, the second end of the first capacitor C1, the first end of the third capacitor C3 and the first end of the first inductor L1 are connected, the second end of the second capacitor C2, the first end of the fourth capacitor C4 and the second end of the first inductor L1 are connected, the second end of the third capacitor C3, the first end of the fifth capacitor C5 and the first end of the second inductor L2 are connected, the second end of the fourth capacitor C4, the second end of the fifth capacitor C5 and the first end of the third inductor L3 are connected, the second end of the second inductor L2, the first end of the sixth capacitor C6 and the first end of the seventh capacitor C7 are connected, the second end of the third inductor L3, the second end of the sixth capacitor C6 and the first end of the eighth capacitor C8 are connected, the second end of the seventh capacitor C7 and the first end of the first resistor R1 are connected, the second end of the eighth capacitor C8 and the second end of the first resistor R1 are connected, and the two ends of the first resistor R1 constitute the signal output end of the wideband receiving circuit 31.

[0079] In this embodiment, the first capacitor C1, the second capacitor C2, the first inductor L1, the third capacitor C3, and the fourth capacitor C4 constitute a T-type high-pass filter circuit to achieve high-pass filtering. The fifth capacitor C5, the second inductor L2, the third inductor L3, and the sixth capacitor C6 constitute a Π-type low-pass filter circuit to achieve low-pass filtering. The seventh capacitor C7, the eighth capacitor C8, and the first resistor R1 constitute an RC high-pass filter circuit to achieve high-pass filtering. After receiving the communication signal from the coupling circuit 10, the broadband receiving circuit 31 performs high-pass filtering, low-pass filtering, and high-pass filtering in sequence to obtain the broadband communication signal in the communication signal.

[0080] Different frequency bands of filtering can be achieved by configuring the various components in the broadband receiving circuit 31.

[0081] like Figure 3 As shown, in an optional embodiment, the narrowband receiving circuit 32 includes a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a fourth inductor L4, and a fifth inductor L5.

[0082] The first ends of the second resistor R2 and the third resistor R3 constitute the signal input terminal of the narrowband receiving circuit 32. The second end of the second resistor R2, the first end of the ninth capacitor C9, the first end of the fourth inductor L4, and the first end of the fourth resistor R4 are connected. The second ends of the third resistor R3, the second end of the ninth capacitor C9, the second end of the fourth inductor L4, and the first end of the fifth resistor R5 are connected. The second end of the fourth resistor R4, the first end of the fifth inductor L5, the first end of the tenth capacitor C10, the first end of the twelfth capacitor C12, and the first end of the sixth resistor R6 are connected. The second ends of the fifth resistor R5, the second end of the fifth inductor L5, the first end of the eleventh capacitor C11, the first end of the thirteenth capacitor C13, and the second end of the sixth resistor R6 are connected. The second ends of the tenth capacitor C10 and the eleventh capacitor C11 are grounded. The second ends of the twelfth capacitor C12 and the thirteenth capacitor C13 constitute the signal output terminal of the narrowband receiving circuit 32.

[0083] In this embodiment, the second resistor R2, the third resistor R3, and the ninth capacitor C9 constitute an RC low-pass filter circuit for low-pass filtering. The fourth inductor L4, the fourth resistor R4, the fifth resistor R5, and the fifth inductor L5 constitute an RL low-pass filter circuit for low-pass filtering. The tenth capacitor C10, the eleventh capacitor C11, the twelfth capacitor C12, the thirteenth capacitor C13, and the sixth resistor R6 constitute a T-type high-pass filter circuit for high-pass filtering. After receiving the communication signal from the coupling circuit 10, the narrowband receiving circuit 32 performs low-pass filtering, low-pass filtering, and high-pass filtering in sequence to obtain the narrowband communication signal in the communication signal.

[0084] Wherein, the filter of different frequency band can be realized by setting each component in the narrow-band receiving circuit 32.

[0085] Wherein, the switching circuit 33 can use different switching switches, switching chips, etc. In an optional embodiment, as shown in the figure, Figure 3 The switching circuit 33 includes:

[0086] The first switching circuit 331 is connected between the wide-band receiving circuit 31 and the processor 40. The first switching circuit 331 is triggered on by the first switching control signal and transmits the wide-band communication signal, and is triggered off by the second switching control signal.

[0087] The second switching circuit 332 is connected between the narrow-band receiving circuit 32 and the processor 40. The second switching circuit 332 is triggered on by the second switching control signal and transmits the narrow-band communication signal, and is triggered off by the first switching control signal.

[0088] In this embodiment, in normal operation, the processor 40 outputs the first switching control signal to the first switching circuit 331 and the second switching circuit 332. The first switching circuit 331 is turned on, and the second switching circuit 332 is turned off. The switching circuit 33 switches the connection between the wide-band receiving circuit 31 and the processor 40. The wide-band receiving circuit 31 obtains the wide-band communication signal from the coupling circuit 10 and transmits it to the processor 40 through the switching circuit 33, which can achieve the purpose of high communication frequency and fast transmission rate.

[0089] When the photovoltaic grid-connected inverter system finds that the distance between the two modules is far away during installation or debugging, or finds that the wide-band communication signal has frequency band interference and poor communication effect during use, the processor 40 outputs the second switching control signal to the first switching circuit 331 and the second switching circuit 332. The second switching circuit 332 is turned on, and the first switching circuit 331 is turned off. The switching circuit 33 switches the connection between the narrow-band receiving circuit 32 and the processor 40. The narrow-band receiving circuit 32 obtains the narrow-band communication signal from the coupling circuit 10 and transmits it to the processor 40 through the switching circuit 33. The narrow-band communication signal works in a lower communication frequency band, reduces frequency band interference, and can achieve a longer communication distance, meet the communication coverage requirements of the photovoltaic grid-connected inverter system, and improve communication reliability.

[0090] Wherein, the wide-band communication signal and the narrow-band communication signal are differential signals. The wide-band communication signal includes a first sub-wide-band communication signal Hp_IN and a second sub-wide-band communication signal Hn_IN with the same amplitude and opposite phase. The narrow-band communication signal includes a first sub-narrow-band communication signal Np_IN and a second sub-narrow-band communication signal Nn_IN with the same amplitude and opposite phase.

[0091] The first sub-wideband communication signal Hp_IN and the second sub-wideband communication signal Hn_IN are input from the first capacitor C1 and the second capacitor C2 of the wideband receiving circuit 31, and output from both ends of the first resistor R1 to the first switch circuit 331 corresponding to two sub-wideband communication signals. In an alternative embodiment, the first switch circuit 331 includes a first switch K1 and a second switch K2, the first end of the first switch K1 and the first end of the second switch K2 are respectively connected to both ends of the first resistor R1, and the second end of the first switch K1 and the second end of the second switch K2 constitute the signal output end of the first switch circuit 331. When the first switching control signal is received, the first switch K1 and the second switch K2 are triggered to conduct and transmit the wideband communication signal to the processor 40, and when the second switching control signal is received, the first switch K1 and the second switch K2 are triggered to turn off and cut off the transmission of the wideband communication signal.

[0092] The first sub-narrowband communication signal Np_IN and the second sub-narrowband communication signal Nn_IN are input from the second resistor R2 and the third resistor R3 of the narrowband receiving circuit 32, and output from the second end of the twelfth capacitor C12 and the second end of the thirteenth capacitor C13 to the second switch circuit 332 corresponding to two sub-narrowband communication signals. In an alternative embodiment, the second switch circuit 332 includes a third switch K3 and a fourth switch K4, the first end of the third switch K3 is connected to the second end of the twelfth capacitor C12, the first end of the fourth switch K4 is connected to the second end of the thirteenth capacitor C13, and the second end of the third switch K3 and the second end of the fourth switch K4 constitute the signal output end of the second switch circuit 332. When the second switching control signal is received, the third switch K3 and the fourth switch K4 are triggered to conduct and transmit the narrowband communication signal to the processor 40, and when the first switching control signal is received, the third switch K3 and the fourth switch K4 are triggered to turn off and cut off the transmission of the narrowband communication signal.

[0093] Among them, the first switch K1 and the second switch K2 can adopt the same type of switch device, the third switch K3 and the fourth switch K4 can adopt the same switch device, the first switch K1 and the third switch K3 can adopt the opposite type of switch device, for example, the first switch K1 and the second switch K2 adopt NMOS tubes or NPN triodes, and the third switch K3 and the fourth switch K4 adopt PMOS tubes or PNP triodes, and the specific switch structure is not limited.

[0094] In another alternative embodiment, as shown in Figure 4 The carrier receiving circuit 30 includes:

[0095] The wideband receiving circuit 31 is connected with the coupling circuit 10 and the processor 40 respectively, triggered to conduct and transmit the wideband communication signal by the first switching control signal, and triggered to turn off by the second switching control signal;

[0096] The narrow-band receiving circuit 32 is connected with the coupling circuit 10 and the processor 40 respectively, is triggered on by the second switching control signal and transmits the narrow-band communication signal, and is triggered off by the first switching control signal.

[0097] In the embodiment, the wide-band receiving circuit 31 and the narrow-band receiving circuit 32 are connected in parallel between the coupling circuit 10 and the processor 40, and the wide-band receiving circuit 31 and the narrow-band receiving circuit 32 have corresponding switch structures inside.

[0098] In normal operation, the processor 40 outputs the first switching control signal to the wide-band receiving circuit 31 and the narrow-band receiving circuit 32, the wide-band receiving circuit 31 is turned on, the narrow-band receiving circuit 32 is turned off, the wide-band receiving circuit 31 obtains the wide-band communication signal from the coupling circuit 10 and transmits it to the processor 40, and the communication frequency is high and the transmission rate is fast.

[0099] When the photovoltaic grid-connected inverter system finds that the distance between two modules is far away during installation or debugging, or finds that the wide-band communication signal has frequency band interference and the communication effect is poor during use, the processor 40 outputs the second switching control signal to the wide-band receiving circuit 31 and the narrow-band receiving circuit 32, the narrow-band receiving circuit 32 is turned on, the wide-band receiving circuit 31 is turned off, the narrow-band receiving circuit 32 obtains the narrow-band communication signal from the coupling circuit 10 and transmits it to the processor 40, the narrow-band communication signal works in a lower communication frequency band, reduces the frequency band interference, and can achieve a longer communication distance, meet the communication coverage requirements of the photovoltaic grid-connected inverter system, and improve the communication reliability.

[0100] Corresponding to the working modes of the wide-band receiving circuit 31 and the narrow-band receiving circuit 32, the wide-band receiving circuit 31 and the narrow-band receiving circuit 32 can be provided with corresponding filter circuits, switch circuits, etc. In an optional embodiment, as shown in the figure, Figure 5 The wide-band receiving circuit 31 includes a wide-band filter circuit 311 and a third switch circuit 312 connected in series between the coupling circuit 10 and the processor 40.

[0101] The wide-band filter circuit 311 is used for filtering the output wide-band communication signal.

[0102] The third switch circuit 312 is also connected with the processor 40, is triggered on by the first switching control signal, and is triggered off by the second switching control signal.

[0103] The narrow-band receiving circuit 32 includes a narrow-band filter circuit 321 and a fourth switch circuit 322 connected in series between the coupling circuit 10 and the processor 40.

[0104] The narrow-band filter circuit 321 is used for filtering the output narrow-band communication signal.

[0105] The fourth switch circuit 322 is also connected with the processor 40, and is triggered to be turned on by the second switching control signal and is triggered to be turned off by the first switching control signal.

[0106] In the embodiment, the output end of the third switch circuit 312 and the output end of the fourth switch circuit 322 are connected in parallel and connected with the signal input end of the processor 40.

[0107] In normal operation, the processor 40 outputs the first switching control signal to the third switch circuit 312 and the fourth switch circuit 322, the third switch circuit 312 is turned on, the fourth switch circuit 322 is turned off, the third switch circuit 312 connects the wideband filter circuit 311 and the processor 40, the wideband filter circuit 311 obtains the communication signal from the coupling circuit 10 and performs filtering processing, thereby outputting the wideband communication signal to the processor 40, so as to achieve the purpose of high communication frequency and fast transmission rate.

[0108] When it is found that the distance between the two modules is far away during installation or debugging of the photovoltaic grid-connected inverter system, or it is found that the wideband communication signal exists frequency band interference and the communication effect is poor during use, the processor 40 outputs the second switching control signal to the third switch circuit 312 and the fourth switch circuit 322, the fourth switch circuit 322 is turned on, the third switch circuit 312 is turned off, the fourth switch circuit 322 connects the narrowband filter circuit 321 and the processor 40, the narrowband filter circuit 321 obtains the communication signal from the coupling circuit 10 and performs filtering processing, thereby outputting the narrowband communication signal to the processor 40, the narrowband communication signal works in a lower communication frequency band, reduces the frequency band interference, can achieve a farther communication distance, meets the communication coverage requirement of the photovoltaic grid-connected inverter system, and improves the communication reliability.

[0109] The wideband filter circuit 311 and the narrowband filter circuit 321 can adopt a filter circuit composed of corresponding inductors, resistors and capacitors, such as shown in FIG. 4. Figure 6 In an optional embodiment, the wideband filter circuit 311 includes a fourteenth capacitor C14, a fifteenth capacitor C15, a sixteenth capacitor C16, a seventeenth capacitor C17, an eighteenth capacitor C18, a nineteenth capacitor C19, a twentieth capacitor C20, a twenty-first capacitor C21, a sixth inductor L6, a seventh inductor L7, an eighth inductor L8 and a seventh resistor R7.

[0110] The first terminal of the fourteenth capacitor C14 and the first terminal of the fifteenth capacitor C15 constitute the signal input terminal of the broadband filter circuit 311. The second terminal of the fourteenth capacitor C14, the first terminal of the sixteenth capacitor C16, and the first terminal of the sixth inductor L6 are connected. The second terminal of the fifteenth capacitor C15, the first terminal of the seventeenth capacitor C17, and the second terminal of the sixth inductor L6 are connected. The second terminal of the sixteenth capacitor C16, the first terminal of the eighteenth capacitor C18, and the first terminal of the seventh inductor L7 are connected. The second terminal of the seventeenth capacitor C17, the second terminal of the eighteenth capacitor C18, and the first terminal of the eighth inductor L8 are connected. The second terminal of the seventh inductor L7, the first terminal of the nineteenth capacitor C19, and the first terminal of the twentieth capacitor C20 are connected. The second terminal of the eighth inductor L8, the second terminal of the nineteenth capacitor C19, and the first terminal of the twentyth capacitor C21 are connected. The second terminal of the twentieth capacitor C20 is connected to the first terminal of the seventh resistor R7. The second terminal of the twentyth capacitor C21 is connected to the second terminal of the seventh resistor R7. The two ends of the seventh resistor R7 constitute the signal output terminal of the broadband filter circuit 311.

[0111] In this embodiment, the fourteenth capacitor C14, the fifteenth capacitor C15, the sixth inductor L6, the sixteenth capacitor C16, and the seventeenth capacitor C17 constitute a T-type high-pass filter circuit to achieve high-pass filtering. The eighteenth capacitor C18, the seventh inductor L7, the eighth inductor L8, and the nineteenth capacitor C19 constitute a Π-type low-pass filter circuit to achieve low-pass filtering. The twentieth capacitor C20, the twenty-first capacitor C21, and the seventh resistor R7 constitute an RC high-pass filter circuit to achieve high-pass filtering. After receiving the communication signal from the coupling circuit 10, the broadband filter circuit 311 performs high-pass filtering, low-pass filtering, and high-pass filtering in sequence to obtain the broadband communication signal in the communication signal, and transmits it to the processor 40 after the third switching circuit 312 is turned on.

[0112] Different frequency bands can be filtered by setting the various components in the broadband filter circuit 311.

[0113] like Figure 6 As shown, in an optional embodiment, the narrowband filter circuit 321 includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a twenty-second capacitor C22, a twenty-third capacitor C23, a twenty-fourth capacitor C24, a twenty-fifth capacitor C25, a twenty-sixth capacitor C26, a ninth inductor L9, and a tenth inductor L10.

[0114] The first end of the eighth resistor R8 and the first end of the ninth resistor R9 constitute a signal input end of the narrow-band filter circuit 321, the second end of the eighth resistor R8, the first end of the twenty-second capacitor C22, the first end of the ninth inductor L9, and the first end of the tenth resistor R10 are connected, the second end of the ninth resistor R9, the second end of the twenty-second capacitor C22, the second end of the ninth inductor L9, and the first end of the eleventh resistor R11 are connected, the second end of the tenth resistor R10, the first end of the tenth inductor L10, the first end of the twenty-third capacitor C23, the first end of the twenty-fifth capacitor C25, and the first end of the twelfth resistor R12 are connected, the second end of the eleventh resistor R11, the second end of the tenth inductor L10, the first end of the twenty-fourth capacitor C24, the first end of the twenty-sixth capacitor C26, and the second end of the twelfth resistor R12 are connected, the second end of the twenty-third capacitor C23 and the second end of the twenty-fourth capacitor C24 are grounded, and the second end of the twenty-fifth capacitor C25 and the second end of the twenty-sixth capacitor C26 constitute a signal output end of the narrow-band filter circuit 321.

[0115] In this embodiment, the eighth resistor R8, the ninth resistor R9, and the twenty-second capacitor C22 constitute an RC low-pass filter circuit for realizing low-pass filtering, the ninth inductor L9, the tenth resistor R10, the eleventh resistor R11, and the tenth inductor L10 constitute an RL low-pass filter circuit for realizing low-pass filtering, the twenty-third capacitor C23, the twenty-fourth capacitor C24, the twenty-fifth capacitor C25, the twenty-sixth capacitor C26, and the twelfth resistor R12 constitute a T-type high-pass filter circuit for realizing high-pass filtering, and the narrow-band filter circuit 321 receives the communication signal from the coupling circuit 10 and sequentially realizes low-pass filtering, low-pass filtering, and high-pass filtering to obtain a narrow-band communication signal in the communication signal.

[0116] Among them, different frequency bands can be realized by setting each component in the narrow-band receiving circuit 32.

[0117] Among them, the wide-band communication signal and the narrow-band communication signal are differential signals, the wide-band communication signal includes a first sub-wide-band communication signal Hp_IN and a second sub-wide-band communication signal Hn_IN with the same amplitude and opposite phase, and the narrow-band communication signal includes a first sub-narrow-band communication signal Np_IN and a second sub-narrow-band communication signal Nn_IN with the same amplitude and opposite phase.

[0118] The first sub-wideband communication signal Hp_IN and the second sub-wideband communication signal Hn_IN are input from the fourteenth capacitor C14 and the fifteenth capacitor C15 of the wideband filter circuit 311, and output from both ends of the seventh resistor R7 to the third switch circuit 312 corresponding to two sub-wideband communication signals. In an alternative embodiment, the third switch circuit 312 includes a fifth switch K5 and a sixth switch K6. The first end of the fifth switch K5 and the first end of the sixth switch K6 are respectively connected to both ends of the seventh resistor R7. The second end of the fifth switch K5 and the second end of the sixth switch K6 constitute a signal output end of the third switch circuit 312. When a first switching control signal is received, the fifth switch K5 and the sixth switch K6 are triggered to turn on and transmit the wideband communication signal to the processor 40. When a second switching control signal is received, the fifth switch K5 and the sixth switch K6 are triggered to turn off and cut off the transmission of the wideband communication signal.

[0119] The first sub-narrowband communication signal Np_IN and the second sub-narrowband communication signal Nn_IN are input from the eighth resistor R8 and the ninth resistor R9 of the narrowband filter circuit 321, and output from the second end of the twenty-fifth capacitor C25 and the second end of the twenty-sixth capacitor C26 to the fourth switch circuit 322 corresponding to two sub-narrowband communication signals. In an alternative embodiment, the fourth switch circuit 322 includes a seventh switch K7 and an eighth switch K8. The first end of the seventh switch K7 is connected to the second end of the twenty-fifth capacitor C25. The first end of the eighth switch K8 is connected to the second end of the twenty-sixth capacitor C26. The second end of the seventh switch K7 and the second end of the eighth switch K8 constitute a signal output end of the fourth switch circuit 322. When a second switching control signal is received, the seventh switch K7 and the eighth switch K8 are triggered to turn on and transmit the narrowband communication signal to the processor 40. When a first switching control signal is received, the seventh switch K7 and the eighth switch K8 are triggered to turn off and cut off the transmission of the narrowband communication signal.

[0120] Among them, the fifth switch K5 and the sixth switch K6 can adopt the same type of switch device, the seventh switch K7 and the eighth switch K8 can adopt the same switch device, the fifth switch K5 and the seventh switch K7 can adopt the opposite type of switch device, for example, the fifth switch K5 and the sixth switch K6 adopt NMOS tubes or NPN transistors, the seventh switch K7 and the eighth switch K8 adopt PMOS tubes or PNP transistors, and the specific switch structure is not limited.

[0121] The power carrier communication circuit 100 can be arranged in the corresponding module in the photovoltaic grid-connected inverter system, the power carrier communication circuit 100 comprises a coupling circuit 10, a carrier sending circuit 20, a carrier receiving circuit 30 and a processor 40, the processor 40 sends a wideband communication signal or a narrowband communication signal through the carrier sending circuit 20 and sends the power signal through the coupling circuit 10, and the processor 40 controls the carrier receiving circuit 30 to switch to a wideband receiving state or a narrowband receiving state through an output switching control signal, and receives the wideband communication signal or the narrowband communication signal, so that different communication switching is realized, the communication reliability is improved, and the communication requirement is met.

[0122] The utility model discloses still put forward a kind of photovoltaic grid-connected inverter system, the photovoltaic grid-connected inverter system includes multiple power carrier communication circuits 100, the specific structure of the power carrier communication circuit 100 refers to above-mentioned embodiment, since the photovoltaic grid-connected inverter system of the utility model adopts all technical solutions of above-mentioned all embodiments, at least have all beneficial effects brought by the technical scheme of above-mentioned embodiment, here no longer tediously repeat.

[0123] Among them, photovoltaic grid-connected inverter system can include photovoltaic assembly, inverter device, booster station device and corresponding module such as equipment, corresponding module is connected with power line between, module is transmitted power signal through power line between, for example, inverter of inverter device and transformer of booster station device are connected with power line, and multiple photovoltaic assemblies are respectively generated alternating current power through inverter device, and are output to transformer of transformer device through the output of combiner box, and are output to grid through transformer and boost.

[0124] Corresponding module is provided with power carrier communication circuit 100 respectively, and communication is carried out through power carrier communication circuit 100, to carry out data interaction, instruction transmission and other work.

[0125] Through the arrangement of power carrier communication circuit 100, photovoltaic grid-connected inverter system can select and switch one of wideband communication or narrowband communication communication mode, wherein, wideband communication has the characteristics of high communication frequency, fast transmission rate but short communication distance, and narrowband communication has the characteristics of low communication frequency, slow transmission rate but long communication distance.

[0126] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A power line carrier communication circuit, characterized by, The application relates to a power line communication device, comprising: a coupling circuit connected with a power line, the coupling circuit being used for realizing coupling carrier or decoupling of a communication signal and a power signal on the power line; a carrier transmitting circuit connected with the coupling circuit, the carrier transmitting circuit being used for transmitting a wideband communication signal or a narrowband communication signal to the coupling circuit, the communication frequency of the wideband communication signal being greater than that of the narrowband communication signal; a carrier receiving circuit connected with the coupling circuit, the carrier receiving circuit being triggered to turn on a first transmission channel and receive the wideband communication signal output by the coupling circuit under the action of a first switching control signal, or being triggered to turn on a second transmission channel and receive the narrowband communication signal output by the coupling circuit under the action of a second switching control signal; a processor connected with the carrier transmitting circuit and the carrier receiving circuit respectively, the processor being used for transmitting the wideband communication signal or the narrowband communication signal and outputting the first switching control signal or the second switching control signal.

2. A power line communication circuit as recited in claim 1, wherein, The coupling circuit comprises a coupler connected with the carrier transmitting circuit, the carrier receiving circuit and the power line respectively.

3. A power line communication circuit as recited in claim 1, wherein, The carrier transmitting circuit comprises a power amplifier, the input end and the output end of the power amplifier constituting the input end and the output end of the carrier transmitting circuit respectively.

4. A power line communication circuit according to any one of claims 1 to 3, wherein The carrier receiving circuit comprises: a wideband receiving circuit connected with the coupling circuit and used for receiving the wideband communication signal; a narrowband receiving circuit connected with the coupling circuit and used for receiving the narrowband communication signal; a switching circuit connected with the wideband receiving circuit, the narrowband receiving circuit and the processor respectively, the switching circuit being triggered to turn on the first transmission channel and transmit the wideband communication signal under the action of the first switching control signal, or being triggered to turn on the second transmission channel and transmit the narrowband communication signal under the action of the second switching control signal.

5. A power line communication circuit as recited in claim 4, wherein, The wideband receiving circuit comprises a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a first inductor, a second inductor, a third inductor and a first resistor; the first end of the first capacitor and the first end of the second capacitor constitute a signal input end of the wideband receiving circuit, the second end of the first capacitor, the first end of the third capacitor and the first end of the first inductor are connected, the second end of the second capacitor, the first end of the fourth capacitor and the second end of the first inductor are connected, the second end of the third capacitor, the first end of the fifth capacitor and the first end of the second inductor are connected, the second end of the fourth capacitor, the second end of the fifth capacitor and the first end of the third inductor are connected, the second end of the second inductor, the first end of the sixth capacitor and the first end of the seventh capacitor are connected, the second end of the third inductor, the second end of the sixth capacitor and the first end of the eighth capacitor are connected, the second end of the seventh capacitor and the first end of the first resistor are connected, the second end of the eighth capacitor and the second end of the first resistor are connected, and the two ends of the first resistor constitute a signal output end of the wideband receiving circuit.

6. A power line communication circuit as recited in claim 4, wherein, The narrow-band receiving circuit comprises a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourth inductor and a fifth inductor; A first end of the second resistor and a first end of the third resistor constitute a signal input end of the narrow-band receiving circuit, a second end of the second resistor, a first end of the ninth capacitor, a first end of the fourth inductor and a first end of the fourth resistor are connected, a second end of the third resistor, a second end of the ninth capacitor, a second end of the fourth inductor and a first end of the fifth resistor are connected, a second end of the fourth resistor, a first end of the fifth inductor, a first end of the tenth capacitor, a first end of the twelfth capacitor and a first end of the sixth resistor are connected, a second end of the fifth resistor, a second end of the fifth inductor, a first end of the eleventh capacitor, a first end of the thirteenth capacitor and a second end of the sixth resistor are connected, a second end of the tenth capacitor and a second end of the eleventh capacitor are grounded, and a second end of the twelfth capacitor and a second end of the thirteenth capacitor constitute a signal output end of the narrow-band receiving circuit.

7. A power line communication circuit as recited in claim 4, wherein, The switching circuit comprises: a first switch circuit connected between the wide-band receiving circuit and the processor, the first switch circuit being triggered to be turned on by the first switching control signal and to transmit the wide-band communication signal, and being triggered to be turned off by the second switching control signal; a second switch circuit connected between the narrow-band receiving circuit and the processor, the second switch circuit being triggered to be turned on by the second switching control signal and to transmit the narrow-band communication signal, and being triggered to be turned off by the first switching control signal.

8. A power line communication circuit as defined in any of claims 1-3, characterized by The carrier receiving circuit comprises: a wide-band receiving circuit connected with the coupling circuit and the processor respectively, the wide-band receiving circuit being triggered to be turned on by the first switching control signal and to transmit the wide-band communication signal, and being triggered to be turned off by the second switching control signal; a narrow-band receiving circuit connected with the coupling circuit and the processor respectively, the narrow-band receiving circuit being triggered to be turned on by the second switching control signal and to transmit the narrow-band communication signal, and being triggered to be turned off by the first switching control signal.

9. A power line carrier communication circuit as recited in claim 8 wherein, The wide-band receiving circuit comprises a wide-band filter circuit and a third switch circuit connected in series between the coupling circuit and the processor; The wide-band filter circuit is configured to filter and output the wide-band communication signal. The third switch circuit is further connected with the processor, and is triggered to be turned on by the first switching control signal and to be turned off by the second switching control signal.

10. A power line communication circuit as recited in claim 9, wherein, The wide-band filter circuit comprises a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor, an eighteenth capacitor, a nineteenth capacitor, a twentieth capacitor, a twenty-first capacitor, a sixth inductor, a seventh inductor, an eighth inductor and a seventh resistor. A first end of the fourteenth capacitor and a first end of the fifteenth capacitor constitute a signal input end of the wideband filter circuit, a second end of the fourteenth capacitor, a first end of the sixteenth capacitor and a first end of the sixth inductor are connected, a second end of the fifteenth capacitor, a first end of the seventeenth capacitor and a second end of the sixth inductor are connected, a second end of the sixteenth capacitor, a first end of the eighteenth capacitor and a first end of the seventh inductor are connected, a second end of the seventeenth capacitor, a second end of the eighteenth capacitor and a first end of the eighth inductor are connected, a second end of the seventh inductor, a first end of the nineteenth capacitor and a first end of the twentieth capacitor are connected, a second end of the eighth inductor, a second end of the nineteenth capacitor and a first end of the twenty-first capacitor are connected, a second end of the twentieth capacitor is connected with a first end of the seventh resistor, a second end of the twenty-first capacitor is connected with a second end of the seventh resistor, and two ends of the seventh resistor constitute a signal output end of the wideband filter circuit.

11. The power line communication circuit of claim 8, wherein the power line communication circuit is configured to communicate with the power line communication circuit of the power control device via the power line. The narrowband receiving circuit comprises a narrowband filter circuit and a fourth switch circuit connected in series between the coupling circuit and the processor. The narrowband filter circuit is configured to filter and output the narrowband communication signal. The fourth switch circuit is further connected with the processor, and is triggered to be turned on by the second switching control signal and is triggered to be turned off by the first switching control signal.

12. A power line communication circuit as recited in claim 11, wherein, The narrowband filter circuit comprises an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a twenty-second capacitor, a twenty-third capacitor, a twenty-fourth capacitor, a twenty-fifth capacitor, a twenty-sixth capacitor, a ninth inductor and a tenth inductor. A first end of the eighth resistor and a first end of the ninth resistor constitute a signal input end of the narrowband filter circuit, a second end of the eighth resistor, a first end of the twenty-second capacitor, a first end of the ninth inductor and a first end of the tenth resistor are connected, a second end of the ninth resistor, a second end of the twenty-second capacitor, a second end of the ninth inductor and a first end of the eleventh resistor are connected, a second end of the tenth resistor, a first end of the tenth inductor, a first end of the twenty-third capacitor, a first end of the twenty-fifth capacitor and a first end of the twelfth resistor are connected, a second end of the eleventh resistor, a second end of the tenth inductor, a first end of the twenty-fourth capacitor, a first end of the twenty-sixth capacitor and a second end of the twelfth resistor are connected, a second end of the twenty-third capacitor and a second end of the twenty-fourth capacitor are grounded, and a second end of the twenty-fifth capacitor and a second end of the twenty-sixth capacitor constitute a signal output end of the narrowband filter circuit.

13. A photovoltaic grid-tie inverter system, characterized by, The power carrier communication circuit comprises a plurality of power carrier communication circuits as claimed in any one of claims 1-12.

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