CN213426164U - Power line carrier communication device and photovoltaic system - Google Patents

Abstract

The utility model provides a power line carrier communication device and photovoltaic system relates to the power technology field. The power line carrier communication device comprises a plurality of hosts connected with the same cable, and the hosts receive signals of the cable through a receiving and filtering loop; the host further comprises an attenuation device, and the attenuation device is communicated with the two input ends of the receiving filter loop and is used for attenuating signals of the communication frequency band of the host. Therefore, the attenuation device is connected in parallel in the receiving filter loop and is used for attenuating the crosstalk signal to a certain extent, so that the interference of the crosstalk signal is reduced, and the reliability of communication is improved.

Description

Power line carrier communication device and photovoltaic system

Technical Field

The utility model relates to an electric power tech field particularly, relates to a power line carrier communication device and photovoltaic system.

Background

Power Line Communication (PLC) is applied to a photovoltaic system, and in order to ensure reliability of long-distance Communication, transmission Power of a carrier signal is high.

The power line carrier communication apparatus includes a plurality of different hosts, PLC signals are transmitted from the hosts, and then the signals are coupled to a line through a transformer, so that normal communication can be performed. Because the communication frequency ranges of different hosts are consistent, signals between different hosts can generate crosstalk, and the reliability of communication is influenced. Therefore, a power line carrier communication apparatus that can solve the problem of crosstalk signals is urgently needed.

SUMMERY OF THE UTILITY MODEL

The utility model provides a problem produce the crosstalk signal between the current different host computers.

In order to solve the above problems, the present invention provides a power line carrier communication device, which includes a plurality of hosts connected to a same cable, wherein the hosts receive signals of the cable through a receiving filter loop; the host further comprises an attenuation device, and the attenuation device is communicated with the two input ends of the receiving filter loop and is used for attenuating signals of the communication frequency band of the host.

Because the output end of each host computer is connected to the cable through the box transformer together, the crosstalk signal between different host computers can pass through the box transformer to influence the signal of another host computer, and because the crosstalk signal transmitted from another host computer and the signal of the host computer are the same frequency signal, and the receiving filter loop in the host computer can only filter out the signal outside the preset frequency band, and can not filter out the crosstalk signal transmitted from other host computers. Therefore, the attenuation device is connected in parallel in the receiving filter loop of the host to attenuate the crosstalk signal to a certain extent, and the receiving filter loop receives little or even no crosstalk signal after the crosstalk signal is attenuated to a certain extent, so that the interference signal transmitted to the carrier modulation and demodulation circuit is less or even nearly none, thereby reducing the interference of the crosstalk signal and improving the reliability of communication.

Optionally, the attenuation device comprises at least one attenuation branch, and different attenuation branches are arranged in parallel.

Optionally, the attenuation branch comprises an attenuation module, which is a capacitor or an LC circuit.

Optionally, the attenuation branch further includes a switch module, and the attenuation module of the same attenuation branch is connected in series with the switch module.

Optionally, the attenuation branch is provided with a plurality of attenuation branches, and each attenuation branch is provided with one switch module.

Optionally, the attenuation branch where at least one of the attenuation modules is located is not provided with the switch module.

Optionally, the damping device further includes a control module, and a plurality of the switch modules are connected to the same control module.

Optionally, the switch module is one of a triode, a field effect transistor and a relay.

Optionally, the capacitance value of the attenuation module is adjusted by switching states of different switch modules.

Secondly, the utility model provides a photovoltaic system, include as above-mentioned power line carrier communication device, power line carrier communication device sets up photovoltaic system's interchange side.

Since the beneficial effects of the photovoltaic system are similar to those of the power line carrier communication device, the details are not repeated herein.

Optionally, the photovoltaic system further comprises a photovoltaic module and an inverter; the direct current side of the photovoltaic system is provided with a plurality of photovoltaic modules, and the photovoltaic modules are connected to the direct current side of the inverter in parallel or in series; and a box transformer is arranged in the power line carrier communication device and is communicated with the alternating current side of the inverter.

Optionally, the number of the inverters, the box transformer transformers and the hosts is multiple, and each inverter and each host are connected in a one-to-one correspondence manner through each box transformer.

Optionally, the photovoltaic system further comprises a plurality of slaves, and an input end of each slave is connected with an output end of each photovoltaic module.

Optionally, the slave machine communicated with the same inverter is in communication connection with the master machine.

Drawings

Fig. 1 is a schematic block diagram of an exemplary power line carrier communication apparatus;

fig. 2 is a schematic structural block diagram of a power line carrier communication device according to an embodiment of the present invention;

fig. 3 is a schematic diagram of an attenuation module according to an embodiment of the present invention;

fig. 4 is a schematic view of an attenuation module according to another embodiment of the present invention;

fig. 5 is a schematic structural block diagram of a power line carrier communication device according to another embodiment of the present invention;

fig. 6 is a schematic diagram of an attenuation module and a switch module according to an embodiment of the present invention;

fig. 7 is a schematic diagram of an attenuation module and a switch module according to another embodiment of the present invention;

fig. 8 is a schematic structural diagram of a photovoltaic system according to an embodiment of the present invention.

Description of reference numerals:

10-a receive filter loop; 20-an attenuation device; 21-an attenuation module; 22-a switch module; 23-a control module; 30-a carrier modulation demodulation circuit; 40-a transmission loop; 50-coupled transformer.

Detailed Description

Power Line carrier Communication (PLC) is applied to photovoltaic system, and in order to guarantee long distance Communication reliability, carrier signal's transmitting Power is great, and the PLC signal passes the case very easily and becomes for PLC host computer produces the crosstalk each other among the entire system, and host computer crosstalk has reduced PLC Communication's reliability, can lead to the unable transmission of PLC host computer signal even, whole Communication system paralyses ' risk.

Specifically, as shown in fig. 1, fig. 1 is a block diagram of an exemplary power line carrier communication apparatus. Two hosts are taken as an example, namely a 1# host and a 2# host. Taking the structure of the # 1 host as an example, the # 1 host includes a carrier modulation and demodulation circuit 30, a transmission loop 40, a receiving filter loop 10 and a coupling transformer 50, wherein one end of the receiving filter loop 10 and one end of the transmission loop 40 are both connected to the carrier modulation and demodulation circuit 30, and the other end of the receiving filter loop 10 and the other end of the transmission loop 40 are both connected to an input end of the coupling transformer 50. The carrier modem circuit 30 is configured to modulate a received or transmitted signal, the transmitting loop 40 is configured to amplify the modulated signal received from the carrier modem circuit and transmit the amplified signal to a line, the receiving filter loop 10 is configured to filter a signal outside a preset frequency band and receive a signal in the preset frequency band, and the coupling transformer 50 is configured to couple a PLC signal of the host to a high-voltage side cable. The power line carrier communication device also comprises a box transformer which is correspondingly connected with the output ends of different hosts of the box transformer. For a host, the output end of the coupling transformer of the host is transmitted to a high-voltage side cable through a box transformer. And a box transformer is arranged between the main machine and the high-voltage side cable, the box transformer is a box transformer for short, and the box transformer is used for converting low voltage into high voltage. That is, a box transformer substation 1# is arranged between the output end of the 1# main machine and the high-voltage side cable, and similarly, a box transformer substation 2# is arranged between the output end of the 2# main machine and the high-voltage side cable, and signals of the 1# main machine and the 2# main machine are coupled to the same high-voltage side cable, so that the high-voltage signals are transmitted to the high-voltage side cable through the box transformer substation.

When the respective hosts normally communicate, taking one host as an example, a signal is sent from the carrier modulation and demodulation circuit 30, amplified through the transmission loop 40, and then transmitted through the coupling transformer 50 and the box transformer, so that a high-voltage signal is transmitted to the high-voltage side cable. The receive filter loop 10 filters out other unwanted signals, receives the correct signal back, and supplies the received signal to the modem circuitry.

Particularly, as the high-voltage side cables of the box transformer substation 1# and the box transformer substation 2# are connected together, the signal of the host 1# passes through the box transformer substation 1# to reach the high-voltage side cable, and then passes through the box transformer substation 2# to return to the host 2#, and in addition, as the two communication frequency bands of the host 1# and the host 2# are the same, the signal of the host 2# cannot be filtered through the receiving attenuation module, so that the signal of the host 2# is interfered by the host 1 #. Conversely, for the same reason, the signal to host 1# is also interfered by host 2 #. When the number of the main machines is more than two, and when the number of the main machines is N, the high-voltage sides of the box transformers are connected together through the same line, so that the problem of interference exists.

For the interference problem, the interference problem can be reduced through the anti-crosstalk tuning compensator, the working principle is that impedance matching is realized on the communication frequency point of the section of track by using impedance matching and matching of a compensation network, the impedance of the communication frequency point of the adjacent track is extremely low, and signals are absorbed. However, in this scheme, different compensators need to be designed according to different communication frequency points, and a scene of simultaneous crosstalk of multiple frequency points cannot be solved, and an application scene is limited, so that the problem of less interference by using the anti-crosstalk tuned compensator is poor in effect.

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.

It is noted that the terms "first," "second," and the like in the description and claims of the present invention and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein.

As shown in fig. 2, fig. 2 is a schematic block diagram of a power line carrier communication apparatus according to an embodiment of the present invention. The application discloses a power line carrier communication device, which comprises a plurality of hosts connected with the same cable, wherein the hosts receive signals of the cable through a receiving and filtering loop 10; the host further comprises an attenuation device 20, and the attenuation device 20 is communicated with two input ends of the receiving filter loop 10 and is used for attenuating signals of the host communication frequency band.

The power line carrier communication device comprises a plurality of main machines, wherein output ends of the plurality of main machines are connected to the same high-voltage side cable, the main machines comprise receiving filter loops 10 and attenuation devices 20, and the receiving filter loops 10 are used for receiving signals returned from the high-voltage side cable. The attenuation device 20 is connected to two input ends of the receiving filter loop 10, that is, the attenuation device 20 is connected in parallel to the receiving filter loop 10. Wherein, what the receiving filter loop 10 filters is the signal outside the host communication frequency band, and the attenuation device 20 is used to attenuate the signal of the host communication frequency band, so that the receiving filter loop receives little or no crosstalk signal.

Because the output end of each host computer is connected to the high-voltage side cable through the box transformer together, the crosstalk signal between different host computers can pass through the box transformer to influence the signal of another host computer, and because the crosstalk signal transmitted from another host computer and the signal of the host computer are the same frequency signal, and the receiving filter loop in the host computer can only filter out the signal outside the preset frequency band, and can not filter out the crosstalk signal transmitted from other host computers. Therefore, the attenuation device is connected in parallel in the receiving filter loop of the host to attenuate the crosstalk signal to a certain extent, and the receiving filter loop receives little or even no crosstalk signal after the crosstalk signal is attenuated to a certain extent, so that the interference signal transmitted to the carrier modulation and demodulation circuit is less or even nearly none, thereby reducing the interference of the crosstalk signal and improving the reliability of communication.

Alternatively, the specific arrangement of the attenuation apparatus 20 may be that the attenuation apparatus 20 includes at least one attenuation branch, and different attenuation branches are arranged in parallel.

Wherein the attenuation device 20 comprises at least one attenuation branch means that the attenuation device may be provided with only one attenuation branch, and the attenuation device may also be provided with only two or three, or even more than three, attenuation branches. When the attenuation device is provided with two or more attenuation branches, different attenuation branches are arranged in parallel.

More specifically, the attenuation branch comprises an attenuation module 21, and the attenuation module 21 is configured to attenuate a signal in the host communication frequency band. The attenuation module is arranged on the attenuation branch and can be used for attenuating signals of the host communication frequency band, so that crosstalk signals can be attenuated to a certain extent, interference of the crosstalk signals is reduced, and reliability of communication is improved.

Since the attenuation device 20 includes at least one attenuation branch, and the attenuation modules 21 are disposed on the attenuation branch, it can be seen that the number of the attenuation modules includes at least one, the number of the attenuation modules disposed may be one, and two or more attenuation modules 21 may also be disposed, and a plurality of the attenuation modules 21 are connected in parallel with the receiving filter circuit 10. The specific setting of the number of the attenuation modules can be selected according to the size of crosstalk signals from other hosts. When the crosstalk signals from other hosts are large, a plurality of attenuation modules can be arranged, so that the filtering effect can be enhanced, namely, the interference signals are attenuated more quickly, the effect is better, and the reliability of communication is improved.

Fig. 3 is a schematic diagram of an attenuation module according to an embodiment of the present invention, in which C1 represents a capacitor. Optionally, for the arrangement of the attenuation module, the attenuation module 21 is a capacitor or an LC circuit. Therefore, the capacitor or the LC circuit is used as the attenuation module, and the circuit structure is simple, easy to realize and low in cost.

When the attenuation module 21 is a capacitor, the number of capacitors may be set to be single, or may be set to be plural according to actual needs. When the number of capacitors is single, a specific filtering principle is to set a threshold in the receiving filter loop by attenuating the amplitude of the incoming crosstalk signal, the threshold being used to identify the signal that can be received by the receiving filter loop, which signal cannot be received by the receiving filter loop when the crosstalk signal is outside the signal range that can be identified by the receiving filter loop. Therefore, the capacitor is arranged as the attenuation module, the amplitude of the crosstalk signal is attenuated by the capacitor, so that the receiving filter loop receives less crosstalk signals and even does not receive the crosstalk signals, and the interference of the crosstalk signals is reduced. To facilitate a better understanding of the principle, the following examples are used for illustration, for example, the waveform amplitude of the normal useful signal is 10, the amplitude of the crosstalk signal is 1, the waveform amplitudes are both reduced after passing through the capacitor 1/10, at this time, the waveform amplitude of the useful signal is 1, the amplitude of the crosstalk signal is 0.1, and the recognizable threshold set in the receiving filter loop is 0.2, and since the crosstalk signal is outside the recognizable threshold, the receiving filter loop cannot receive the interference signal, so that the effect of attenuating the crosstalk signal is achieved. Where the amplitude of the reduction of the useful signal and of the crosstalk signal, as illustrated by 1/10, is determined on the basis of the capacitance values, the amplitude of the reduction or, as it were, the amplitude of the attenuation, differs when the capacitance values differ. It should be noted that the data cited in the examples are for illustrative purposes only and do not represent actual values.

Of course, the value of the capacitor can also be set to be multiple, and the scheme of arranging multiple capacitors relative to a single capacitor can enhance the filtering effect, so that the interference of the interference signal is reduced as much as possible. The capacitance values can be selected to be the same, and can be set to be capacitors with different capacitance values, so that the capacitance values can be flexibly selected according to actual requirements and can meet the requirements.

As shown in fig. 4, fig. 4 is a schematic diagram of an attenuation module, i.e. an LC circuit according to another embodiment of the present invention, wherein C1 represents a capacitor, and L1 represents an inductor. Optionally, when the attenuation module is an LC circuit, the LC circuit includes a capacitor and an inductor, the capacitor and the inductor being connected in series.

The capacitor and the inductor are connected in series to form the band elimination filter, so that the band elimination filter can inhibit crosstalk signals of a specific frequency band, a receiving filter loop cannot receive the crosstalk signals, interference of the crosstalk signals is less, and the effect of reducing crosstalk signal interference can be achieved.

When the attenuation module is an LC circuit, the number of the LC circuits may be set to be plural, and the plural LC circuits are arranged in parallel, so that the attenuation enhancement effect may be achieved.

Alternatively, the attenuation module may be a capacitor or an LC circuit, and may be another filter such as an RC circuit, as long as the attenuation module can attenuate the interference of the crosstalk signal.

As shown in fig. 5, fig. 5 is a schematic block diagram of a power line carrier communication device according to another embodiment of the present invention. S1-Sn in FIG. 5 represents a switch module, and C1-Cn represents an attenuation module. Optionally, the attenuation branch further includes a switch module 22, and the attenuation module 21 of the same attenuation branch is connected in series with the switch module 22.

The attenuation modules 21 and the switch modules 22 of the same attenuation branch are connected in series, and the number of the connected attenuation modules 21 is selected by controlling the switch modules 22 to be closed. Therefore, the selection of the attenuation modules is more flexible, the corresponding proper attenuation modules can be selected for different systems, the control of the attenuation modules is conveniently realized, the flexibility is stronger, and the attenuation effect on crosstalk signals is better.

Optionally, a plurality of attenuation branches are provided, and each attenuation branch is provided with one switch module 22.

When the number of the attenuation branches is multiple, a plurality of attenuation modules are arranged on the corresponding attenuation branches, each attenuation branch is provided with one switch module, namely, the branch where each attenuation module is located is correspondingly provided with one switch module for controlling, and the switch module is controlled to be closed so as to select the connected attenuation module.

Because the switch modules are arranged on the attenuation branches, which path of switch is opened or closed can be selected according to actual needs and the influence of crosstalk signals of other hosts on the host in practical application, and then the accessed filtering module is selected, so that the interference of the crosstalk signals on the host is reduced to the minimum, and the communication reliability is improved. In addition, each branch can be controlled conveniently, and the attenuation module is high in selection flexibility to meet different system requirements. It should be noted that, for the scheme that each attenuation branch where each attenuation module is located is provided with a corresponding switch module, in order to ensure that interference of crosstalk signals can be reduced at the same time, at least one switch module needs to be closed, so that at least one attenuation module is connected to ensure that the function of reducing signal crosstalk can be achieved.

Specifically, when the same attenuation branch is provided with both the switch module and the attenuation module, the attenuation module may be a capacitor or a band-stop filter composed of a capacitor and an inductor, where, taking the attenuation module as the capacitor as an example, the attenuation branch where one capacitor is located is correspondingly provided with the switch module, and the switch module is a controllable switch. Therefore, the controllable switch is arranged on the branch where the capacitor is located, and the capacitor is conveniently controlled. When a plurality of controllable switches are arranged correspondingly, capacitors with different capacitance values are selected to be connected in parallel through different controllable switches, so that crosstalk signals with different sizes are adapted, and the attenuation speed and effect of the crosstalk signals are improved.

Of course, when the number of the switch modules is plural, the number of the switch modules may not correspond to the number of the attenuation modules, that is, the branches where the attenuation modules are located may not be completely provided with the switch modules in one-to-one correspondence. Optionally, the switch module 22 is not disposed on the attenuation branch where at least one of the attenuation modules 21 is located.

The attenuation branch where the at least one attenuation module is located is not provided with the switch module, that is, the number of the switch modules is provided with a plurality of attenuation modules, and the number of the switch modules is less than that of the attenuation modules. In order to better understand the content of the present solution, a specific example is as follows, taking the attenuation modules as capacitors and the switch modules as controllable switches as an example, when the number of the attenuation modules is set to four, that is, the number of the capacitors is set to four, the four capacitors are arranged in parallel, and the number of the controllable switches may be set to one, two, or three. In the branch provided with a controllable switch, the controllable switch is connected in series with the capacitor. When the number of the controllable switches is set to be one, a switch can be connected in series with a branch where any one of the capacitors is located, so that the capacitance value connected in parallel can be selected, and interference of crosstalk signals is reduced. Similarly, when the number of the controllable switches is two, any two branches where the capacitors are located can be selected to be provided with the controllable switches, and when the two controllable switches are arranged, the capacitance value of the capacitors connected in parallel can be selected according to the size of the crosstalk signal, so that the controllable switch is convenient to control, more in selectivity and more flexible in selection. When the number of the controllable switches is three, namely, the branch where only one capacitor is located is not provided with the controllable switches, and the branches where other capacitors are located are provided with the controllable switches, so that more flexible selection can be realized, the size of the capacitance value of the parallel connection can be controlled by closing the switches according to the size of the crosstalk signal, the control is convenient, and the effect of reducing the interference of the crosstalk signal is also ensured. It should be noted that, when the attenuation module includes a capacitor and an inductor, the principle of the controllable switch setting is similar, and is not described herein again.

In particular, when the number of the attenuation modules is only one, and the number of the controllable switches is only one, in order to ensure that the interference of the crosstalk signal can be reduced, the controllable switches need to be in a closed state, so that the effect of attenuating the crosstalk signal can be achieved.

Optionally, when the number of the switch modules is provided with a plurality, the damping device further includes a control module 23, and a plurality of the switch modules 22 are connected to the same control module 23.

Therefore, the on-off of the switch modules is controlled by the same control module, the operation is simple, the use of the controller is reduced, and the cost is reduced.

Optionally, when the number of the switch modules is plural, one switch module is connected with one control module, and the on-off of the plural switch modules is controlled by different control modules individually.

Like this, a plurality of the break-make of switch module is respectively through different control module independent control, can reduce like this when a certain control module breaks down, and other control module are to the influence of whole circuit, and the flexibility is higher, and in addition, independent control can be according to the actual selected access corresponding decay module, and realizes that the precision of control is higher, reduces the influence of crosstalk signal to minimum.

Optionally, for the selection of the switch module, the switch module is one of a triode, a field effect transistor and a relay.

The switch module is a controllable switch which can be set to be one of a triode, a field effect transistor and a relay, so that the circuit structure is simple and easy to realize. Of course, the switch module may be other controllable switches as long as the selective attenuation module can be controlled.

Optionally, the capacitance value of the attenuation module 21 is adjusted by switching the states of the different switch modules 22.

Therefore, the controllable switch is arranged on the branch where the capacitor is located, the capacitor is conveniently controlled, and the capacitors with different capacitance values are connected in parallel by switching different controllable switches so as to adapt to crosstalk signals with different sizes and improve the attenuation speed and effect of the crosstalk signals.

For the state switching of the switch module, the state switching can be realized by counting the light loss rate, and when the light loss rate is detected to be less than five per thousand, the communication of the system can be considered to be normal. When the range of the light loss rate is in the abnormal range, the interference signals transmitted by other hosts are received, and at the moment, different capacitance values can be selected by controlling the on-off states of different controllable switches, so that the purpose of dynamically adjusting the capacitance value accessed to the capacitor by switching different controllable switches is achieved, and the interference of other signals is reduced.

As shown in fig. 6, fig. 6 is a schematic diagram of an attenuation module and a switch module according to an embodiment of the present invention. Taking the attenuation module as a capacitor and the switch module as an triode as an example, the triode can be a PNP type triode, the plurality of triodes are Q1-Qn, and the plurality of capacitors are C1-Cn. The specific circuit connection is as follows: one end of the C1 is connected with the emitter of the Q1, the other end of the C1 is connected with the second end of the input end of the coupling transformer, the base of the Q1 is connected with the control module, and the collector of the Q1 is connected with the first end of the input end of the coupling transformer. The triodes and capacitors of the other branches are similar to the connection method of the first branch, and the other branches are connected with the first branch in parallel.

Fig. 7 is a schematic diagram of an attenuation module and a switch module according to another embodiment of the present invention, as shown in fig. 7. When the attenuation module comprises a capacitor and an inductor, and the switch module is a triode, the triode can be a PNP type triode, the plurality of triodes are Q1-Qn, the plurality of capacitors are C1-Cn, the plurality of inductors are L1-Ln, and the specific circuit connection is as follows: the C1 and the L1 are connected in series to be connected with the emitter of the Q1, the other end of the C1 is connected with the second end of the input end of the coupling transformer, the base of the Q1 is connected with the control module, and the collector of the Q1 is connected with the first end of the input end of the coupling transformer. The triodes and capacitors of the other branches are similar to the connection method of the first branch, and the other branches are connected with the first branch in parallel.

It should be noted that, for whether crosstalk of signals occurs between different hosts, it can be determined whether the box transformer can normally communicate. For example, when the master and the slave communicate, the loss rate may be counted, and when the loss rate is detected to be less than five per thousand, the communication of the system may be considered to be normal. When the range of the light loss rate is in the abnormal range, the interference signals transmitted by other hosts are received, at the moment, the control module can control the switch module to be switched off, and then different capacitance values are selected, so that the interference of other signals is reduced.

The application discloses power line carrier communication device includes two host computers at least, the host computer includes carrier modulation and demodulation circuit 30, transmission circuit 40, receives filter circuit 10, coupling transformer 50, decay module 21, switch module 22 and control module 23, receive filter circuit 10's one end transmission circuit 40's one end all with carrier modulation and demodulation circuit 30 connects, receive filter circuit 10's the other end transmission circuit 40's the other end all is connected with coupling transformer 50's input. The attenuation module 21 is connected in series with the switch module 22 and is commonly connected to the input of the coupling transformer 50. The control module 23 is connected to the switch module 22, and is configured to control on/off of the switch module 22, so as to control a capacitance value of the attenuation module connected to a host. The power carrier communication device further comprises a box transformer and a high-voltage side cable, wherein one end of the output end of the coupling transformer 50 is connected to the box transformer through a capacitor, and then signal transmission to the high-voltage side cable is achieved through the box transformer. During normal communication, a signal is sent from the host and then coupled to the high-side cable through the box transformer. Similarly, for another main unit, the structure is the same as that of the main unit, and the final output terminal is also connected to the high-voltage cable side. Therefore, the attenuation module is connected in parallel in the receiving filter loop of the host, namely, the crosstalk signals are attenuated to a certain extent, and the attenuation module absorbs the interference signals, so that the interference of the crosstalk signals among different hosts is reduced, and the reliability of communication is improved.

It should be noted that the attenuation module and the filter circuit in the present application are substantially different. Generally, the filter circuit is used for attenuating the passing signal as much as possible, and the attenuation amplitude is large; and the amplitude of the attenuation module signal in this application is less proportion attenuation when attenuating, as long as make the crosstalk signal can filter just, if use the great filter circuit of attenuation amplitude in this application, the too big communication quality that can make of attenuation amplitude receives the influence.

As shown in fig. 8, fig. 8 is a schematic structural diagram of a photovoltaic system according to an embodiment of the present invention. The application also discloses a photovoltaic system, including the aforesaid power line carrier communication device, power line carrier communication device sets up photovoltaic system's the side of exchanging. Because the output end of each host computer is connected to the high-voltage side cable through the box transformer together, the crosstalk signal between different host computers can pass through the box transformer to influence the signal of another host computer, and because the crosstalk signal transmitted from another host computer and the signal of the host computer are the same frequency signal, and the receiving filter loop in the host computer can only filter out the signal outside the preset frequency band, and can not filter out the crosstalk signal transmitted from other host computers. Therefore, the attenuation module is connected in parallel in the receiving filter loop of the host, namely, the crosstalk signal is attenuated to a certain degree, and the receiving filter loop receives little or even cannot receive the crosstalk signal after the crosstalk signal is attenuated to a certain degree, so that the interference signal transmitted to the carrier modulation and demodulation circuit is less or even nearly not, the interference of the crosstalk signal is reduced, and the reliability of communication is improved. The power line carrier communication device is applied to the photovoltaic system, and therefore the reliability of communication of the photovoltaic system is improved. Optionally, the photovoltaic system further includes a photovoltaic module and an inverter, a plurality of the photovoltaic modules are disposed on a dc side of the photovoltaic system, and the photovoltaic modules are connected to a dc side of the inverter in parallel or in series; and a box transformer is arranged in the power line carrier communication device and is communicated with the alternating current side of the inverter.

The photovoltaic modules are connected in series or in parallel, the photovoltaic modules can be photovoltaic panels, the output ends of the photovoltaic panels are connected with the direct current side of an inverter, the inverter is used for converting direct current signals into alternating current signals, and the alternating current side of the inverter is connected with a box transformer of the power line carrier communication device. The box transformer is used for converting a low-voltage signal of the inverter into a high-voltage signal, so that the high-voltage signal is output to the cable. It is possible for the cable to be connected to the public power grid.

Therefore, by arranging the photovoltaic module and the inverter, the direct current signal of the photovoltaic module is converted into an alternating current signal through the inverter, and the low-voltage alternating current signal of the power line carrier communication device is converted into a high-voltage signal through the box transformer, so that the high-voltage signal is coupled to the cable. Therefore, the photovoltaic module and the inverter are arranged, and conversion and transmission of signals are facilitated.

Optionally, the number of the inverters, the box transformer transformers and the hosts is multiple, and each inverter and each host are connected in a one-to-one correspondence manner through each box transformer.

The number of the main machines can be set to be multiple, and the number of the corresponding inverters and the box transformer is also set to be multiple. Each host is connected with the inverter through the box transformer, and the number of the hosts can be adjusted according to actual needs, so that the hosts can also be adjusted.

Therefore, the inverters and the hosts are connected in a one-to-one correspondence mode through the box transformer transformers, so that the signals of the hosts can be conveniently and smoothly sent, and the signals can be conveniently sent.

Optionally, the photovoltaic system further comprises a plurality of slaves, and an input end of each slave is connected with an output end of each photovoltaic module.

Thus, the normal communication of signals is facilitated through the arrangement of the slave machines.

Optionally, the slave connected to the same inverter is communicatively connected to the master. The slave may be a shutdown or optimizer of the photovoltaic system, such that a slave state may be selected according to actual system requirements.

In this way, the slave is in communication connection with the master, so that normal communication between the master and the slave is ensured.

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.

Claims (14)

1. A power line carrier communication apparatus includes a plurality of hosts connected to the same cable, the hosts receiving signals of the cable through a reception filter circuit (10); the host is characterized by further comprising an attenuation device (20), wherein the attenuation device (20) is communicated with two input ends of the receiving filter loop (10) and is used for attenuating signals of the communication frequency band of the host.

2. The power line carrier communication device according to claim 1, wherein the attenuation device (20) comprises at least one attenuation branch, different attenuation branches being arranged in parallel.

3. The power line carrier communication device according to claim 2, wherein the attenuation branch comprises an attenuation module (21), the attenuation module (21) being a capacitor or an LC circuit.

4. The power line carrier communication device according to claim 3, wherein the attenuation branch further comprises a switch module (22), the attenuation module (21) of the same attenuation branch being connected in series with the switch module (22).

5. The power-line carrier communication device according to claim 4, wherein a plurality of attenuation branches are provided, and one switch module (22) is provided on each attenuation branch.

6. Power line carrier communication device according to claim 4, characterized in that said switch module (22) is not provided on said attenuation branch on which at least one of said attenuation modules (21) is located.

7. The power-line carrier communication device according to claim 5, wherein the attenuation device further comprises a control module (23), and a plurality of the switch modules (22) are connected to the same control module (23).

8. The power line carrier communication device according to claim 4, wherein the switch module (22) is one of a triode, a field effect transistor and a relay.

9. The power line carrier communication device according to claim 5 or 6, characterized in that the capacitance value of the attenuation module (21) is adjusted by switching the states of the different switch modules (22).

10. A photovoltaic system, comprising a power line carrier communication device according to any one of claims 1 to 9, arranged on the ac side of the photovoltaic system.

11. The photovoltaic system according to claim 10, further comprising a photovoltaic module and an inverter, wherein a plurality of the photovoltaic modules are disposed on the dc side of the photovoltaic system, and the photovoltaic modules are connected in parallel or in series to the dc side of the inverter; and a box transformer is arranged in the power line carrier communication device and is communicated with the alternating current side of the inverter.

12. The photovoltaic system of claim 11, wherein the number of the inverters, the box transformer and the hosts is plural, and each inverter and each host are connected in a one-to-one correspondence through each box transformer.

13. The photovoltaic system of claim 12, further comprising a plurality of slaves, an input of each slave being connected to an output of each photovoltaic module.

14. The pv system of claim 13 wherein the slaves communicating with the same inverter are communicatively coupled to the master.

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