Photovoltaic direct current communication device based on power line carrier and application method

Abstract

The invention provides a photovoltaic direct-current communication device based on a power line carrier and an application method, and aims to solve the problem of long-distance data transmission between equipment in a centralized photovoltaic system. The device comprises a local communication unit which is used for carrying out data communication with external equipment, receiving an external signal and transmitting the external signal to a main control unit; the main control unit is used for receiving an external signal, performing data analysis on the external signal and transmitting the analyzed external signal to the carrier transmitting unit; the carrier transmitting unit is used for receiving the analyzed external signal, amplifying the analyzed external signal to obtain an amplified external signal, and transmitting the amplified external signal to the carrier coupling unit; the carrier coupling unit is used for receiving the amplified external signal and coupling the amplified external signal to a photovoltaic direct current transmitting loop; and the power supply unit is used for receiving external voltage and providing voltage for each unit of the device.

Description

Technical Field

[0001] This application relates to the field of photovoltaic power technology, specifically to a photovoltaic DC communication device and application method based on power line carrier. Background Technology

[0002] In centralized photovoltaic systems, since the DC combiner boxes are distributed within a one-kilometer radius (some distances are as long as 1 kilometer) around the inverter, the 485 communication method is used. However, this method requires the laying of communication lines, which presents problems such as difficulty in laying cables, complicated construction, and high communication laying costs.

[0003] In existing technologies, the most effective way to address the aforementioned problems is to use communication methods with minimal or no cabling to avoid the deployment of communication cables during the communication process from the centralized photovoltaic DC combiner box to the inverter. Therefore, wireless communication technologies such as Bluetooth, WiFi, and Sub-G are often used. While this can reduce cabling to some extent, the environmental characteristics of photovoltaic power plants, such as the long communication distances in centralized photovoltaic sites and the presence of dense photovoltaic supports and panels, make wireless signals susceptible to obstruction. The presence of photovoltaic supports and panels significantly attenuates wireless signals, limiting signal propagation distance and affecting the stability and reliability of communication.

[0004] Therefore, in view of the above problems, this application proposes a photovoltaic DC communication device based on power line carrier. Summary of the Invention

[0005] This application provides a photovoltaic DC communication device and application method based on power line carrier to solve the problem of long-distance data transmission between combiner boxes and inverters in centralized photovoltaic systems.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] In a first aspect, this application provides a photovoltaic DC communication device based on power line carrier, the device comprising: a local communication unit, a main control unit, a carrier transmission unit, a carrier coupling unit, and a power supply unit;

[0008] The main control unit is connected to the local communication unit and the carrier transmission unit, and the carrier transmission unit is connected to the carrier coupling unit.

[0009] The local communication unit is used to communicate with external devices, receive external signals, and transmit external signals to the main control unit.

[0010] The main control unit is used to receive external signals, perform data parsing on the external signals, and transmit the parsed external signals to the carrier transmission unit.

[0011] The carrier transmitting unit is used to receive the parsed external signal, amplify the parsed external signal to obtain the amplified external signal, and transmit the amplified external signal to the carrier coupling unit.

[0012] The carrier coupling unit is used to receive the amplified external signal and couple the amplified external signal to the photovoltaic DC transmission circuit;

[0013] The power supply unit is used to receive external voltage and provide voltage to the various units of the device.

[0014] One possible design scheme, the device of the first aspect further includes a carrier receiving unit, which is connected to the main control unit and the carrier coupling unit respectively;

[0015] The carrier coupling unit is used to couple the power carrier signal on the photovoltaic DC transmission circuit to the carrier receiving unit;

[0016] The carrier receiving unit is used to receive power carrier signals, filter the power carrier signals to obtain filtered power carrier signals, and transmit the filtered power carrier signals to the main control unit.

[0017] The main control unit is used to receive the filtered power line carrier signal, perform data parsing on the filtered power line carrier signal, and transmit the parsed power line carrier signal to the local communication unit.

[0018] One possible design scheme, the device of the first aspect further includes a voltage monitoring unit, which is connected to the main control unit;

[0019] A voltage monitoring unit is used to receive external voltage, wherein the external voltage is consistent with the external voltage received by the power supply unit;

[0020] The voltage monitoring unit is also used to transmit the external voltage to the main control unit in a certain proportion by using a resistor voltage divider.

[0021] Correspondingly, the main control unit is used to receive the voltage transmitted by the voltage monitoring unit in order to monitor the external voltage.

[0022] One possible design scheme, the device of the first aspect further includes a carrier transmitting unit comprising a differential signal amplifier chip, a DC bias resistor, a bias current regulating resistor, an amplification gain regulating resistor, a first filter capacitor, a first isolation capacitor and a transient voltage suppression diode, wherein the bias current regulating resistor, the amplification gain regulating resistor, the filter capacitor and the isolation capacitor and the transient voltage suppression diode are respectively connected to the pins of the differential signal amplifier chip;

[0023] Differential signal amplifier chip, used to amplify the analyzed external signal;

[0024] A DC bias resistor is used to bias the voltage supplied by the power supply unit.

[0025] The bias current adjustment resistor is used to adjust the bias current entering the differential signal amplifier chip.

[0026] Amplification gain adjustment resistor, used to adjust the gain of the differential signal amplifier chip;

[0027] The first filter capacitor is used to filter out high-frequency noise or interference in the circuit.

[0028] The first isolation capacitor is used to isolate the DC component in the circuit.

[0029] Transient voltage suppression diodes are used to protect circuits from damage caused by transient voltages.

[0030] One possible design scheme, the first aspect of the device further includes a carrier receiving unit comprising a bandpass filter, a second isolation capacitor, a limiting diode, a load resistor, and a second filter capacitor, wherein the second isolation resistor, the limiting diode, the load resistor, and the second filter capacitor are respectively connected to the bandpass filter;

[0031] A bandpass filter is used to filter power line carrier signals;

[0032] The second isolation capacitor is used to isolate the DC component in the circuit.

[0033] A limiting diode is used to limit the amplitude of a signal.

[0034] Load resistors are used to provide a suitable load for power line carrier signals;

[0035] The second filter capacitor is used to filter out high-frequency noise or interference in the circuit.

[0036] One possible design scheme, the first aspect of the device, further includes a carrier coupling unit comprising a coupling transformer and an isolation 5kV safety capacitor. The carrier coupling unit uses the isolation 5kV safety capacitor to isolate DC power and the coupling transformer to isolate strong and weak current power.

[0037] One possible design, the device of the first aspect, further includes a local communication unit comprising a half-duplex RS485 transceiver, the local communication unit using the half-duplex RS485 transceiver to convert the parsed power line carrier signal received from the main control unit into an RS485 signal for output to external devices.

[0038] One possible design scheme, the first aspect of the device further includes a local communication unit that includes a TVS diode, a thermistor and an ESD diode. The TVS diode and the thermistor are used to enable the local communication unit to have high voltage protection, and the ESD diode is used to provide electrostatic protection for the main control unit.

[0039] One possible design scheme, the device of the first aspect, further includes an external voltage range of 5 to 24V, and a power supply unit including a primary power supply and a secondary power supply;

[0040] The primary power supply includes a BOOST boost chip, which stabilizes the received external voltage of 5-24V at a 24V output voltage.

[0041] The secondary power supply includes two BUCK step-down chips and one LDO regulator chip, which are used to convert the stable 24V voltage into 5V, 3.3V and 1.1V to supply the main control unit, carrier receiving unit and local communication unit respectively.

[0042] Secondly, this application provides an application method for a photovoltaic DC communication device based on power line carrier, the application method comprising: a local communication unit receiving external signals from external devices and transmitting the external signals to a main control unit;

[0043] The main control unit receives external signals, performs data parsing on the external signals, and transmits the parsed external signals to the carrier transmission unit;

[0044] The carrier transmission unit receives the parsed external signal, amplifies the parsed external signal to obtain the amplified external signal, and transmits the amplified external signal to the carrier coupling unit.

[0045] The carrier coupling unit receives the amplified external signal and couples the amplified external signal to the photovoltaic DC transmission circuit;

[0046] The local communication unit, main control unit, carrier transmission unit, and carrier coupling unit are powered by the power supply unit.

[0047] In this embodiment, a photovoltaic DC communication device based on power line carrier is used, consisting of a local communication unit, a main control unit, a carrier transmitting unit, a carrier coupling unit, a power supply unit, a carrier receiving unit, and a voltage monitoring unit, to solve the problem of long-distance data transmission between combiner boxes and inverters in centralized photovoltaic systems. Compared with the traditional RS485 communication method, this application utilizes existing power lines for data transmission, which significantly reduces the cost of the communication system.

[0048] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 A schematic diagram of the structure of a photovoltaic DC communication device based on power line carrier provided in an embodiment of this application;

[0051] Figure 2 The circuit schematic of the voltage monitoring unit provided in the embodiments of this application;

[0052] Figure 3 The circuit schematic of the carrier transmission unit provided in the embodiments of this application;

[0053] Figure 4 The circuit schematic diagram of the carrier receiving unit provided in the embodiments of this application;

[0054] Figure 5 The circuit schematic of the carrier coupling unit provided in the embodiments of this application;

[0055] Figure 6 Circuit schematic diagram of the local communication unit provided in the embodiments of this application;

[0056] Figure 7 The circuit schematic of the primary power supply provided in the embodiments of this application;

[0057] Figure 8 Circuit principle of the secondary power supply provided in the embodiments of this application Figure 1 :

[0058] Figure 9 Circuit principle of the secondary power supply provided in the embodiments of this application Figure 2 ;

[0059] Figure 10 Circuit principle of the secondary power supply provided in the embodiments of this application Figure 3 . Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments in this specification clearer, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. The components of the embodiments of this specification described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0061] Therefore, the following detailed description of the embodiments of this specification provided in the accompanying drawings is not intended to limit the scope of the claimed specification, but merely to illustrate selected embodiments of this specification. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without inventive effort are within the scope of protection of this specification.

[0062] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0063] In the description of the embodiments in this specification, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the product is in use. These are merely for the convenience of describing this specification and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this specification. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0064] Furthermore, the use of terms such as "horizontal," "vertical," and "sag" does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0065] In the description of the embodiments in this specification, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this specification according to the specific circumstances.

[0066] The following section will describe in detail a photovoltaic DC communication device based on power line carrier, which aims to solve the problem of long-distance data transmission between combiner boxes and inverters in centralized photovoltaic systems.

[0067] Figure 1 This is a schematic diagram of the structure of a photovoltaic DC communication device based on power line carrier provided in an embodiment of this application.

[0068] like Figure 1 As shown, the photovoltaic DC communication device based on power line carrier mainly includes: a local communication unit, a main control unit, a carrier transmission unit, a carrier coupling unit, and a power supply unit.

[0069] The main control unit is connected to the local communication unit and the carrier transmission unit, and the carrier transmission unit is connected to the carrier coupling unit.

[0070] The local communication unit is used to communicate with external devices, receive external signals, and transmit external signals to the main control unit.

[0071] The main control unit is used to receive external signals, perform data parsing on the external signals, and transmit the parsed external signals to the carrier transmission unit.

[0072] The carrier transmitting unit is used to receive the parsed external signal, amplify the parsed external signal to obtain the amplified external signal, and transmit the amplified external signal to the carrier coupling unit.

[0073] The carrier coupling unit is used to receive the amplified external signal and couple the amplified external signal to the photovoltaic DC transmission circuit;

[0074] The power supply unit is used to receive external voltage and provide voltage to the various units of the device.

[0075] It is understood that the above-mentioned device mainly realizes the transmission of external signals to the photovoltaic DC transmission circuit through the local communication unit, main control unit, carrier transmission unit, carrier coupling unit and power supply unit.

[0076] Furthermore, the aforementioned external equipment may be a combiner box or inverter, or other possible equipment, without specific restrictions.

[0077] In this embodiment, the device further includes a carrier receiving unit, which is connected to the main control unit and the carrier coupling unit respectively.

[0078] The carrier coupling unit is used to couple the power carrier signal on the photovoltaic DC transmission circuit to the carrier receiving unit;

[0079] The carrier receiving unit is used to receive power carrier signals, filter the power carrier signals to obtain filtered power carrier signals, and transmit the filtered power carrier signals to the main control unit.

[0080] The main control unit is used to receive the filtered power line carrier signal, perform data parsing on the filtered power line carrier signal, and transmit the parsed power line carrier signal to the local communication unit.

[0081] It is understood that the above-mentioned device mainly realizes the transmission of power carrier signals from the photovoltaic DC transmission circuit to the local communication unit through a carrier coupling unit, a carrier receiving unit, a main control unit, and a local communication unit.

[0082] In this embodiment, the device further includes a voltage monitoring unit, which is connected to the main control unit;

[0083] The voltage monitoring unit is used to receive external voltage, which is consistent with the external voltage received by the power supply unit. The voltage monitoring unit is also used to transmit the external voltage to the main control unit in a certain proportion by using a resistor voltage divider. Correspondingly, the main control unit is used to receive the voltage transmitted by the voltage monitoring unit to monitor the external voltage.

[0084] It is understandable that the circuit diagram of the voltage monitoring unit described above is as follows: Figure 2 As shown, the external voltage is divided by resistors R14 and R21 with an accuracy of one-thousandth. The resistance of R14 is 9 times that of R21. The main control unit receives the voltage after the voltage division (or, in other words, the main control unit performs 12-bit high-precision sampling on the voltage after the voltage division) and, through the principle of resistor voltage division, deduces the external voltage, i.e., the power supply voltage.

[0085] In this embodiment, the carrier transmission unit includes a differential signal amplifier chip, a DC bias resistor, a bias current adjustment resistor, an amplification gain adjustment resistor, a first filter capacitor, a first isolation capacitor, and a transient voltage suppression diode. The bias current adjustment resistor, the amplification gain adjustment resistor, the filter capacitor, the isolation capacitor, and the transient voltage suppression diode are respectively connected to the pins of the differential signal amplifier chip.

[0086] Differential signal amplifier chip, used to amplify the analyzed external signal;

[0087] A DC bias resistor is used to bias the voltage supplied by the power supply unit.

[0088] The bias current adjustment resistor is used to adjust the bias current entering the differential signal amplifier chip.

[0089] Amplification gain adjustment resistor, used to adjust the gain of the differential signal amplifier chip;

[0090] The first filter capacitor is used to filter out high-frequency noise or interference in the circuit.

[0091] The first isolation capacitor is used to isolate the DC component in the circuit.

[0092] Transient voltage suppression diodes are used to protect circuits from damage caused by transient voltages.

[0093] like Figure 3As shown, the differential signal amplifier chip is U2; the DC bias resistors include R9, R13, R19, R27, R17, and R18; the bias current adjustment resistor includes R25; the amplification gain adjustment resistor includes R11, R16, and R20; the first filter capacitor includes C21, C14, C15, and C18; the first isolation capacitor includes C27, C30, C20, and C49; and the transient voltage suppression diode is TVS3.

[0094] It is understandable that the aforementioned carrier transmission unit uses the voltage provided by the power supply unit and the differential signal amplifier chip U2 to amplify the analyzed external signal, so that the peak value of the analyzed external signal can reach 48V, and the communication distance can reach 1KM. That is, by increasing the signal strength, the stability and reliability of communication over a long distance are ensured.

[0095] In this embodiment, the carrier receiving unit includes a bandpass filter, a second isolation capacitor, a limiting diode, a load resistor, and a second filter resistor. The second isolation resistor, the limiting diode, the load resistor, and the second filter resistor are respectively connected to the bandpass filter.

[0096] A bandpass filter is used to filter power line carrier signals;

[0097] The second isolation capacitor is used to isolate the DC component in the circuit.

[0098] A limiting diode is used to limit the amplitude of a signal.

[0099] Load resistors are used to provide a suitable load for power line carrier signals;

[0100] The second filter capacitor is used to filter out high-frequency noise or interference in the circuit.

[0101] like Figure 4 As shown, the bandpass filter includes C25, R10, C24, L2, L6, C12, C36, L4, L11, C10, C39, L5, L21, C13, and C46, ​​and can also be called an LRC filter; the second isolation capacitor includes C19 and C29; the limiting diode includes D1 and D3; the load resistor includes R5, R26, R7, and R22; and the second filter capacitor includes C23.

[0102] It is understood that the 200kHz to 12MHz bandpass filter contained within the aforementioned carrier receiving unit filters the power line carrier signal to obtain the filtered power line carrier signal. In other words, the bandpass filter in the carrier receiving unit can filter out noise and interference that may be introduced during power line carrier transmission, retaining only the effective signal, thus enabling power line carrier communication distances up to 1km.

[0103] In the embodiment, the carrier coupling unit includes a coupling transformer and an isolation 5kV safety capacitor. The carrier coupling unit uses the isolation 5kV safety capacitor to isolate DC power and the coupling transformer to isolate strong and weak current power.

[0104] It is understandable that the above-mentioned carrier coupling unit, such as Figure 5 As shown, it contains a 5kV withstand voltage safety capacitor C65 to isolate DC, and can be used in DC circuits not exceeding 2kV. It basically covers the highest voltage output bus of a single combiner box in a centralized photovoltaic power station in China. In addition, it also uses a coupling transformer T1 to isolate strong and weak currents.

[0105] In addition, such as Figure 5 As shown, the aforementioned carrier coupling unit is also connected to the external photovoltaic power generation circuit via an external terminal J8 (i.e., a screw-type terminal).

[0106] In an embodiment, such as Figure 6 As shown, the aforementioned local communication unit includes a half-duplex RS485 transceiver U3. The local communication unit uses this half-duplex RS485 transceiver to convert the parsed power line carrier signal (also known as a TTL signal) received from the main control unit into an RS485 signal for output to external devices. Similarly, the half-duplex RS485 transceiver can also convert external signals from external devices into TTL signals for output to the main control unit; these details will not be elaborated further here.

[0107] In the embodiment, the local communication unit further includes a TVS diode, a thermistor, and an ESD diode. The TVS diode and the thermistor are used to enable the local communication unit to have high voltage protection, and the ESD diode is used to provide electrostatic protection for the main control unit.

[0108] It is understandable that the aforementioned local communication units, such as Figure 6 As shown, the local communication unit consists of a thermistor RT1 and a TVS diode D7. When the external input voltage exceeds the VBR of the TVS diode, the TVS diode breaks down and conducts, momentarily switching from an open-circuit state to a near-short-circuit state. This allows a large current to flow back to the external circuit through the TVS diode's circuit, thus protecting the subsequent circuitry. When the current becomes excessive, reaching the thermistor's limit, the thermistor heats up, and its resistance changes from several Ω to the kΩ level, thereby switching the current and protecting the TVS diode. After the overvoltage condition ends, the thermistor slowly returns to normal temperature, and the circuit resumes normal operation. In other words, high voltage protection is achieved through the TVS diode and thermistor.

[0109] In addition, the aforementioned local communication units, such as Figure 6As shown, the local communication unit includes three ESD protection diodes, D6, D8 and D9. Based on the characteristics of SED diodes, they suppress transient voltage spikes exceeding 5V, thereby achieving electrostatic protection for the downstream main control unit.

[0110] In this embodiment, the external voltage range is 5–24V. The power supply unit includes a primary power supply and a secondary power supply.

[0111] The primary power supply includes a BOOST boost chip, which stabilizes the received 5-24V external voltage at a 24V output voltage. The secondary power supply includes two BUCK buck chips and one LDO regulator chip, which convert the stable 24V voltage into 5V, 3.3V, and 1.1V to supply the main control unit, carrier receiving unit, and local communication unit, respectively.

[0112] It is understandable that the above power supply unit, such as Figures 7-10 As shown. Specifically, the above-mentioned primary power supply, refer to... Figure 7 It consists of a Zener diode D4 and a current-limiting resistor R1. When the external power supply voltage is lower than 3.3V, the Zener diode is in the off state, and pin 4 of the BOOST boost chip UA1 is pulled up to the external power supply voltage by R1. When the external power supply voltage is higher than 3.3V, the Zener diode is reverse-broken down and is in the working state, clamping the voltage across it to about 3.3V, thus ensuring that pin 4 of the UA1 chip is always at 3.3V, achieving the voltage regulation function.

[0113] The above-mentioned secondary power supply, refer to Figure 8-10 Two BUCK step-down chips, U9 and U7, and one LDO voltage regulator chip, U5, are used to convert a stable 24V voltage into 5V, 3.3V, and 1.1V to supply the main control unit, carrier receiving unit, and local communication unit, respectively.

[0114] In summary, this application embodiment employs a photovoltaic DC communication device based on power line carrier, consisting of a local communication unit, a main control unit, a carrier transmitting unit, a carrier coupling unit, a power supply unit, a carrier receiving unit, and a voltage monitoring unit, to solve the problem of long-distance data transmission between combiner boxes and inverters in centralized photovoltaic systems. Furthermore, compared to the traditional RS485 communication method, this application utilizes existing power lines for data transmission, significantly reducing the cost of the communication system.

[0115] The above combination Figures 1-10 The photovoltaic DC communication device based on power line carrier provided in the embodiments of this application is described in detail. The application method of the photovoltaic DC communication device based on power line carrier is described below.

[0116] The local communication unit receives external signals from external devices and transmits these signals to the main control unit.

[0117] The main control unit receives external signals, performs data parsing on the external signals, and transmits the parsed external signals to the carrier transmission unit;

[0118] The carrier transmission unit receives the parsed external signal, amplifies the parsed external signal to obtain the amplified external signal, and transmits the amplified external signal to the carrier coupling unit.

[0119] The carrier coupling unit receives the amplified external signal and couples the amplified external signal to the photovoltaic DC transmission circuit;

[0120] The local communication unit, main control unit, carrier transmission unit, and carrier coupling unit are powered by the power supply unit.

[0121] Or perhaps,

[0122] The carrier coupling unit couples the power carrier signal on the photovoltaic DC transmission circuit to the carrier receiving unit;

[0123] The carrier receiving unit receives the power carrier signal, filters the power carrier signal to obtain the filtered power carrier signal, and transmits the filtered power carrier signal to the main control unit.

[0124] The main control unit receives the filtered power line carrier signal, performs data parsing on the filtered power line carrier signal, and transmits the parsed power line carrier signal to the local communication unit.

[0125] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure (including the claims) is limited to these examples; within the scope of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of this application as described above, which are not provided in the details for the sake of brevity.

[0126] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photovoltaic DC communication device based on power line carrier, characterized in that, The device includes: a local communication unit, a main control unit, a carrier transmission unit, a carrier coupling unit, and a power supply unit; The main control unit is connected to the local communication unit and the carrier transmission unit, and the carrier transmission unit is connected to the carrier coupling unit; The local communication unit is used to communicate with external devices, receive external signals, and transmit the external signals to the main control unit. The main control unit is used to receive the external signal, perform data parsing on the external signal, and transmit the parsed external signal to the carrier transmission unit; The carrier transmitting unit is used to receive the parsed external signal, amplify the parsed external signal to obtain an amplified external signal, and transmit the amplified external signal to the carrier coupling unit. The carrier coupling unit is used to receive the amplified external signal and couple the amplified external signal to the photovoltaic DC transmission circuit; The power supply unit is used to receive external voltage and provide voltage to the various units of the device.

2. The photovoltaic DC communication device based on power line carrier according to claim 1, characterized in that, The device further includes a carrier receiving unit, which is connected to the main control unit and the carrier coupling unit respectively. The carrier coupling unit is used to couple the power carrier signal on the photovoltaic DC transmission circuit to the carrier receiving unit; The carrier receiving unit is used to receive the power carrier signal, filter the power carrier signal to obtain a filtered power carrier signal, and transmit the filtered power carrier signal to the main control unit. The main control unit is used to receive the filtered power line carrier signal, perform data parsing on the filtered power line carrier signal, and transmit the parsed power line carrier signal to the local communication unit.

3. The photovoltaic DC communication device based on power line carrier according to claim 1 or 2, characterized in that, The device further includes a voltage monitoring unit, which is connected to the main control unit; The voltage monitoring unit is used to receive an external voltage, wherein the external voltage is consistent with the external voltage received by the power supply unit; The voltage monitoring unit is also used to transmit the external voltage to the main control unit in a certain proportion by means of resistor voltage division; Correspondingly, the main control unit is used to receive the voltage transmitted by the voltage monitoring unit in order to monitor the external voltage.

4. The photovoltaic DC communication device based on power line carrier according to claim 1, characterized in that, The carrier transmitting unit includes a differential signal amplifier chip, a DC bias resistor, a bias current adjustment resistor, an amplification gain adjustment resistor, a first filter capacitor, a first isolation capacitor, and a transient voltage suppression diode. The bias current adjustment resistor, the amplification gain adjustment resistor, the filter capacitor, the isolation capacitor, and the transient voltage suppression diode are respectively connected to the pins of the differential signal amplifier chip. The differential signal amplifier chip is used to amplify the analyzed external signal; The DC bias resistor is used to bias the voltage provided by the power supply unit; The bias current adjustment resistor is used to adjust the bias current entering the differential signal amplifier chip; The gain adjustment resistor is used to adjust the gain of the differential signal amplifier chip. The first filter capacitor is used to filter out high-frequency noise or interference in the circuit; The first isolation capacitor is used to isolate the DC component in the circuit; The transient voltage suppression diode is used to protect the circuit from transient voltage damage.

5. The photovoltaic DC communication device based on power line carrier according to claim 2, characterized in that, The carrier receiving unit includes a bandpass filter, a second isolation capacitor, a limiting diode, a load resistor, and a second filter capacitor. The second isolation resistor, the limiting diode, the load resistor, and the second filter capacitor are respectively connected to the bandpass filter. The bandpass filter is used to filter the power line carrier signal; The second isolation capacitor is used to isolate the DC component in the circuit; The limiting diode is used to limit the amplitude of the signal; The load resistor is used to provide a suitable load for the power line carrier signal; The second filter capacitor is used to filter out high-frequency noise or interference in the circuit.

6. The photovoltaic DC communication device based on power line carrier according to claim 1 or 2, characterized in that, The carrier coupling unit includes a coupling transformer and an isolation 5kV safety capacitor. The carrier coupling unit uses the isolation 5kV safety capacitor to isolate DC power and the coupling transformer to isolate strong and weak current power.

7. The photovoltaic DC communication device based on power line carrier according to claim 2, characterized in that, The local communication unit includes a half-duplex RS485 transceiver, which is used to convert the parsed power line carrier signal received from the main control unit into an RS485 signal and output it to external devices.

8. The photovoltaic DC communication device based on power line carrier according to claim 1 or 2, characterized in that, The local communication unit also includes a TVS diode, a thermistor, and an ESD diode. The TVS diode and the thermistor enable the local communication unit to have high voltage protection, and the ESD diode provides electrostatic protection for the main control unit.

9. The photovoltaic DC communication device based on power line carrier according to claim 1 or 2, characterized in that, The external voltage range is 5 to 24V, and the power supply unit includes a primary power supply and a secondary power supply. The primary power supply includes a BOOST boost chip, which is used to stabilize the received external voltage of 5-24V at a 24V output voltage. The secondary power supply includes two BUCK step-down chips and one LDO regulator chip, used to convert the stable 24V voltage into 5V, 3.3V and 1.1V to supply the main control unit, the carrier receiving unit and the local communication unit respectively.

10. An application method for a photovoltaic DC communication device based on power line carrier, applied to the photovoltaic DC communication device based on power line carrier as described in any one of claims 1-9, characterized in that, The application method includes: The local communication unit receives external signals from external devices and transmits the external signals to the main control unit; The main control unit receives the external signal, performs data parsing on the external signal, and transmits the parsed external signal to the carrier transmission unit; The carrier transmitting unit receives the parsed external signal, amplifies the parsed external signal to obtain an amplified external signal, and transmits the amplified external signal to the carrier coupling unit. The carrier coupling unit receives the amplified external signal and couples the amplified external signal to the photovoltaic DC transmission circuit; The local communication unit, the main control unit, the carrier transmission unit, and the carrier coupling unit are powered by a power supply unit.

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