Information transmission method and system

Abstract

The invention relates to an information transmission method and system. The system comprises a first node device and a second node device. The first node equipment modulates original data and / or a control signal on a bus through PWM (Pulse Width Modulation) to form an intermediate signal taking current or voltage as a carrier; the bus transmits the intermediate signal to the second node equipment in a broadcasting manner; the second node device decodes the intermediate signal and recovers the original data and / or the control signal; each of the first node device and the second node device comprises a current and voltage sampling circuit and a PWM switching circuit. According to the invention, a low-cost modulation mode of an additional circuit is not needed, and communication can be realized only by arranging or adding the PWM switching circuit and the current and voltage sampling circuit on the communication link and cooperating with corresponding sending modulation and receiving demodulation programs.

Description

Technical Field

[0001] The invention belongs to the field of communications, and in particular relates to an information transmission method and system. Background Art

[0002] Power Line Carrier (PLC) communication refers to a special communication method that uses high-voltage power lines (usually 35kV and above), medium-voltage power lines (10kV) or power lines (380 / 220V) as information transmission media for voice or data transmission. At present, PLC communication mainly uses a dedicated PLC modulation circuit at the sending end, and uses an encoder, a digital-to-analog converter, a power amplifier, and a coupling circuit to superimpose and couple the signal to the power line. At the receiving end, a decoder, a coupling circuit, a PLC demodulator, signal processing and coding demodulation are also required to achieve data restoration. However, the hardware cost used in this communication method is high, and the prices of PLC chips, power amplifiers, coupling circuits, and filter circuits are not low. At the same time, due to the presence of very indispensable circuits and chips, there are many constraints on the size of the product, and miniaturization is not allowed. There will be very large limitations in practical applications. In addition, in practical applications, due to the presence of a large number of strong interferences such as harmonics and switching noise on the power line, it brings great challenges to small signal detection in circuit design.

[0003] In terms of communication reliability, since power line carrier communication itself is to superimpose small signals on the high-voltage bus in the form of voltage, the bus itself has the characteristics of high voltage noise, which can easily drown out the effective signal, so a strong noise suppression circuit and encoding and decoding method are required to ensure the reliability of the communication link. Especially before PLC networking, nodes in different network segments are very likely to cause cable coupling and crosstalk when adjacent to each other, which brings a lot of inconvenience to the application. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide an information transmission method and system, which can solve the current problems of high PLC communication cost and unreliable information transmission.

[0005] To solve the above technical problems, according to the first aspect of this document, there is provided an information transmission method, comprising a first node device and a second node device; the first node device modulates the original data and / or control signal on a bus through PWM to form an intermediate signal with current or voltage as the carrier; the bus transmits the intermediate signal to the second node device in a broadcast manner; the second node device decodes the intermediate signal and restores the original data and / or control signal.

[0006] In one embodiment of the present invention, the first node device and the second node device both include a current and voltage sampling circuit and a PWM switch circuit.

[0007] In one embodiment of the present invention, the first node device modulates the original data and / or control signal through PWM on the bus to form an intermediate signal with current or voltage as the carrier, including: the PWM switching circuit PWM modulates the original data and / or control signal on the bus to form an intermediate signal with current or voltage as the carrier; the second node device decodes the intermediate signal and restores the original data and / or control signal, including: the current and voltage sampling circuit samples the intermediate signal and demodulates it into the original data and / or control signal.

[0008] In one embodiment of the present invention, the first node device and the second node device are connected in a series structure or a parallel structure, the first node device serves as a master node, and the second node device serves as a slave node.

[0009] In one embodiment of the present invention, the first node device and the second node device are connected in a series structure, the first node device modulates the original data and / or control signal current into a current signal as an intermediate signal to the bus through the PWM switching circuit, and the second node device samples the intermediate signal through the current and voltage sampling circuit and current demodulates it into the original data and / or control signal.

[0010] In one embodiment of the present invention, the first node device and the second node device are connected in a series structure, the second node device modulates the original data and / or control signal voltage into a voltage signal as an intermediate signal to the bus through the PWM switching circuit, and the first node device samples the intermediate signal through the current and voltage sampling circuit and voltage demodulates it into the original data and / or control signal.

[0011] In one embodiment of the present invention, the first node device and the second node device are connected in a parallel structure, the first node device modulates the original data and / or control signal voltage into a voltage signal as an intermediate signal to the bus through the PWM switching circuit, and the second node device samples the intermediate signal through the current and voltage sampling circuit and voltage demodulates it into the original data and / or control signal.

[0012] In one embodiment of the present invention, the first node device and the second node device are connected in a parallel structure, the second node device modulates the original data and / or control signal current into a current signal as an intermediate signal to the bus through the PWM switching circuit, and the first node device samples the intermediate signal through the current and voltage sampling circuit and current demodulates it into the original data and / or control signal.

[0013] In an embodiment of the present invention, the control signal includes a synchronization header, a peak current, a peak voltage and a reference time.

[0014] In one embodiment of the present invention, the peak current is taken as the maximum value, and the maximum value is divided into n equal parts, where n can be selected to be 1, 2, 3, 4, . . . 16.

[0015] In one embodiment of the present invention, the PWM switching circuit adopts a switching power supply with a power conversion topology structure of Buck / Boost / half-bridge / full-bridge / DAB to control the voltage and current amplitude, and uses the input and output current or voltage as a control loop to control the input and output parameters.

[0016] To solve the above technical problem, according to the second aspect of this document, the present invention provides an information transmission system, which adopts any one of the above information transmission methods.

[0017] According to another aspect of the present invention, a computer-readable storage medium is provided, on which computer program instructions are stored, and when the instructions are executed by a processor, any of the above-mentioned information transmission methods is implemented.

[0018] The specific steps of the information transmission system are consistent with the above method and will not be repeated here.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. The present invention is a low-cost modulation method that does not require additional circuits. It only requires a PWM switch circuit and a current and voltage sampling circuit to be or can be added to the communication link, and the corresponding transmission modulation and reception demodulation programs can be used to achieve communication.

[0020] 2. The modulation method adopted by the present invention, especially the current modulation method, has almost zero attenuation at any position or node in the busbar of the series combination in the photovoltaic and energy storage fields. Due to the presence of inductance in the busbar, the current interference is very small, and there is almost no common-mode interference, which can greatly improve the reliability of signal transmission.

[0021] 3. In the cluster application of multi-wire bundles, the power carrier communication uses the current coupling transmission mode to have almost innate immunity to crosstalk, and can basically achieve zero crosstalk transmission with the filtering algorithm. The present invention adopts basic PWM switching circuit modulation, combined with a general signal processing algorithm and data demodulation, which is highly versatile and has extremely low requirements for hardware circuits.

[0022] 4. The information transmission method of the present invention can be used as an efficient supplement to PLC information transmission. Before the PLC is networked, the networking command or networking ID is transmitted through current modulation, which can effectively avoid PLC network crosstalk, and can effectively avoid PLC network radiation and adjacent cable coupling crosstalk; it is easier to achieve double-blind automatic networking of host nodes without a whitelist. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the information transmission method of the present invention in which the main sender and the slave receive; Figure 2 is a flow chart of the information transmission method from sender to receiver of the present invention; Figure 3 A schematic diagram of an information transmission method of a master-slave node in a series structure of the present invention; Figure 4 A schematic diagram of an information transmission method for master and slave nodes in a parallel structure of the present invention; Figure 5 It is a schematic diagram of hexadecimal modulation transmission of the present invention. DETAILED DESCRIPTION

[0024] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of this article clearer, the technical solutions in the embodiments of this article will be clearly and completely described below in conjunction with the drawings in the embodiments of this article. Obviously, the described embodiments are part of the embodiments of this article, not all of the embodiments. Based on the embodiments in this article, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this article. It should be noted that the embodiments in this article and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0026] Unless the context clearly requires otherwise, the words "include", "comprising" and similar words throughout the specification and claims should be construed as inclusive.

[0027] In power conversion and remote control application scenarios, information transmission methods such as data transmission and command reception are required. The information transmission method provided by the present invention is based on power control itself to perform signal encoding, transmission and reception, without additional hardware circuits and complex demodulation algorithms; and can transmit information or commands in a very reliable manner.

[0028] A first specific embodiment of the present invention provides an information transmission method, including a first node device and a second node device; the first node device modulates the original data and / or control signal through PWM on a bus to form an intermediate signal with current or voltage as the carrier; the bus transmits the intermediate signal to the second node device in a broadcast manner; the second node device decodes the intermediate signal and restores the original data and / or control signal.

[0029] Specifically, the original data and / or control signal is sent by a control center in the transmission system, such as a host or a cloud server. The present invention realizes information transmission based on the host's regulation of bus current.

[0030] In particular, the first node device and the second node device both include a current and voltage sampling circuit and a PWM switch circuit; wherein the node with the PWM switch circuit can be used as a sending node, and the node with the current and voltage sampling circuit can be used as a receiving node. The first node device and the second node device can both be used as a sending node or a receiving node, and are not limited to the first node device sending or the second node device receiving information.

[0031] Specifically, the first node device and the second node device are connected in series or parallel, the first node device is used as a master node, and the second node device is used as a slave node. The present invention has multiple information transmission modes, such as master sending and slave receiving or slave sending and master receiving.

[0032] In a specific embodiment, Figure 1 The information transmission method shown in the figure is that the first node device modulates the original data and / or control signal through PWM on the bus to form an intermediate signal with current or voltage as the carrier; the bus transmits the intermediate signal to the second node device in a broadcasting manner; the second node device decodes the intermediate signal and restores the original data and / or control signal.

[0033] In a specific embodiment, Figure 2 The information transmission method from sender to receiver is shown. The second node device modulates the original data and / or control signal on the bus through PWM to form an intermediate signal with current or voltage as the carrier; the bus transmits the intermediate signal to the first node device in a broadcasting manner; the first node device decodes the intermediate signal and restores the original data and / or control signal.

[0034] In one embodiment of the present invention, the PWM switching circuit PWM modulates the original data and / or control signal on the bus to form an intermediate signal with current or voltage as the carrier; the current and voltage sampling circuit samples the intermediate signal and demodulates it into the original data and / or control signal.

[0035] Specifically, the intermediate signal may be a voltage or current signal that is modulated and superimposed on the bus.

[0036] In one embodiment of the present invention, Figure 3 The information transmission method of the master-slave node in a series structure is shown. The first node device and the second node device are connected in a series structure, the first node device modulates the original data and / or control signal current into a current signal as an intermediate signal to the bus through the PWM switch circuit, and the second node device samples the intermediate signal through the current and voltage sampling circuit and current demodulates it into the original data and / or control signal.

[0037] In one embodiment of the present invention, the first node device and the second node device are connected in a series structure, the second node device modulates the original data and / or control signal voltage into a voltage signal as an intermediate signal to the bus through the PWM switching circuit, and the first node device samples the intermediate signal through the current and voltage sampling circuit and voltage demodulates it into the original data and / or control signal.

[0038] In one embodiment of the present invention, Figure 4 The information transmission method of the master-slave node in parallel structure is shown. The first node device and the second node device are connected in parallel structure, the first node device modulates the voltage of the original data and / or control signal into a voltage signal as an intermediate signal to the bus through the PWM switch circuit, and the second node device samples the intermediate signal through the current and voltage sampling circuit and demodulates the voltage into the original data and / or control signal.

[0039] In one embodiment of the present invention, the first node device and the second node device are connected in a parallel structure, the second node device modulates the original data and / or control signal current into a current signal as an intermediate signal to the bus through the PWM switching circuit, and the first node device samples the intermediate signal through the current and voltage sampling circuit and current demodulates it into the original data and / or control signal.

[0040] Specifically, the present invention can be applied to occasions with current control, such as photovoltaic string inverters, photovoltaic optimizers, photovoltaic shut-off devices, energy storage PCS, street light controllers, centralized lighting power supplies, etc. In these occasions, control data or command transmission is often required, and the transmission of this information is usually very long, and requires strong anti-interference and the need to prevent crosstalk coupling.

[0041] Generally, the first node device can be a device master node, and the second node can be a device slave node. The device master node and the device slave node form a system in series or parallel. In the system formed in series, the current signal can be transmitted to each device sub-node without loss. Similarly, the voltage signal of the system formed in parallel can also be transmitted to each device sub-node. It is very suitable for photovoltaic, energy storage battery and other string occasions.

[0042] In particular, current modulation is particularly prominent in applications. In photovoltaics and energy storage, because of the series combination of components, current transmission can be directly coupled to each device node and is less affected by the switching noise on the node, which can greatly improve the reliability of signal transmission.

[0043] It should be noted that the current modulation method uses the PWM switching circuit to dynamically adjust the current through the input topology of the device on the series bus (such as photovoltaic strings, series battery packs), such as boost, buck, pfc, dab, llc, full bridge, etc., and couples the data or command information to the power supply bus for broadcasting on the same bus.

[0044] It is particularly noted that the voltage modulation method uses voltage modulation on parallel node buses with large internal resistance, such as parallel photovoltaic modules or battery packs with constant current limiting or other constant current sources, to adjust the input voltage to achieve signal transmission.

[0045] In a preferred embodiment, the PWM switch circuit adopts a switching power supply with a power conversion topology structure of Buck / Boost / half-bridge / full-bridge / DAB to control the voltage and current amplitude, and uses the input and output current or voltage as a control loop to control the input and output parameters. In particular, in photovoltaic MPPT, energy storage inverter and other equipment systems, the passive adjustable characteristics of the source itself, current, power, and voltage are used, and modulation technology is used to superimpose the signal on a parameter of current, power, and voltage to realize the transmission of information and commands.

[0046] In a preferred embodiment, the control signal includes a synchronization header, a peak current, a peak voltage and a reference time.

[0047] Specifically, as the establishment of communication, an agreed format or other commonly used asynchronous transmission methods can be used. A handshake mechanism with a synchronization header can also be used. The present invention preferably uses a synchronous transmission method. The synchronization header starts with an agreed current change. The peak current and reference time in the control signal are used for subsequent decoding.

[0048] In the preferred embodiment, in addition to modulating the voltage or current into a binary mode of 0 / 1, it can also be modulated into: taking the peak current as the maximum value, dividing the maximum value into n equal parts, and n dividing the maximum value into n equal parts, where n can be selected as 1, 2, 3, 4...16. Commonly used methods are binary, quaternary, octal, and hexadecimal modulation.

[0049] In a specific embodiment of the present invention, taking hexadecimal modulation as an example, the peak amplitude of the peak current divides the current amplitude into 4 equal parts to implement hexadecimal data transmission modulation.

[0050] Specifically, Figure 5 The schematic diagram of hexadecimal modulation transmission is shown in the figure. The transmission utilizes the high reliability and transmission accuracy of current modulation to realize multi-level modulation. The maximum current of the power is divided into 1 bit, for example, 100mA is 1 bit, and the maximum current is 1.6A, which can realize hexadecimal modulation. The synchronization header starts with the agreed current change, and the peak amplitude can use the current amplitude as the basis for multi-level analysis. For example, the peak current = 2A is divided into 16 equal parts, which can realize hexadecimal data transmission modulation. The edge interval of the handshake signal can be used as the time standard for data synchronization. Initiating a handshake every n moments can calibrate the clock offset. In the application of multi-level transmission, the current amplitude can be cut into several segments, for example, 16 segments can realize hexadecimal number transmission, and the starting header of each packet is the peak current, which is equivalent to the maximum value of the data. The multi-level data transmission method based on current can achieve the expansion of transmission rate by dividing the current size as the data bit system.

[0051] In particular, data based on current modulation can only be transmitted in bursts and cannot occupy the bus all the time, otherwise it will affect the transmission of power in the bus. In many actual applications, data transmission only accounts for a very small part of the operating time, and multi-bit transmission can be used to reduce the time a single data packet occupies on the bus.

[0052] In a preferred embodiment, the original data and / or control signal is demodulated and restored by a current and voltage sampling circuit.

[0053] Specifically, the demodulation based on modulation of parameters such as current only needs to use the voltage and current sampling of the circuit itself, and the noise interference can be suppressed by decoding through the voltage and current detection circuit. In particular, on the device sub-nodes for information transmission, current and voltage acquisition are mostly basic software and hardware functions for system operation. For example, photovoltaic optimizers and circuit breakers will have internal integrated current, voltage and temperature sampling. The native or additional current and voltage capture caches in these systems are used to cache to the communication module processing unit. The communication processing unit decodes the voltage and current signals according to the agreement, such as baud rate synchronization, transmission base number recognition, transmission data parsing, etc., and finally allows the device sub-node to obtain the instructions or data issued by the device master node.

[0054] In order to solve the above technical problems, a second specific embodiment of the present invention provides an information transmission system, wherein the system adopts any one of the above information transmission methods. In order to solve the above technical problems, a third specific embodiment of the present invention provides a computer-readable storage medium, on which computer program instructions are stored, and when the instructions are executed by a processor, any of the above information transmission methods is implemented.

[0055] The present invention relates to an information transmission method and system, including a first node device and a second node device; the first node device modulates the original data and / or control signal on the bus through PWM to form an intermediate signal with current or voltage as the carrier; the bus transmits the intermediate signal to the second node device in a broadcasting manner; the second node device decodes the intermediate signal and restores the original data and / or control signal; the first node device and the second node device both include a current and voltage sampling circuit and a PWM switch circuit. The present invention does not require a low-cost modulation method of additional circuits, and only requires a PWM switch circuit and a current and voltage sampling circuit to be or can be added to the communication link, and cooperates with the corresponding sending modulation and receiving demodulation procedures to achieve communication.

[0056] The modulation method adopted by the present invention, especially the method based on current modulation, has almost zero attenuation at any position or node in the busbar of the series combination in the photovoltaic and energy storage fields, and due to the presence of inductance in the busbar, the current interference is very small, and there is almost no common-mode interference, which can greatly improve the reliability of signal transmission. In cluster applications with multiple wire harnesses, power carrier communication uses the current coupling transmission method, which has almost innate immunity to crosstalk, and can basically achieve zero crosstalk transmission in conjunction with the filtering algorithm. The present invention adopts basic PWM switching circuit modulation, combined with general signal processing algorithms and data demodulation, and has strong versatility and extremely low requirements for hardware circuits. The information transmission method of the present invention can be used as an efficient supplement to PLC information transmission. Before the PLC is networked, the networking command or networking ID is transmitted through current modulation, which can effectively avoid PLC network crosstalk.

[0057] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An information transmission method, characterized in that: It includes a first node device and a second node device; the first node device modulates the original data and / or control signal on the bus through PWM to form an intermediate signal with current or voltage as the carrier; the bus transmits the intermediate signal to the second node device in a broadcast manner; the second node device decodes the intermediate signal and restores the original data and / or control signal.

2. The information transmission method according to claim 1, characterized in that: The first node device and the second node device both include a current and voltage sampling circuit and a PWM switch circuit; The first node device modulates the original data and / or control signal through PWM on the bus to form an intermediate signal with current or voltage as the carrier, including: the PWM switching circuit modulates the original data and / or control signal through PWM on the bus to form an intermediate signal with current or voltage as the carrier; the second node device decodes the intermediate signal and restores the original data and / or control signal, including: the current and voltage sampling circuit samples the intermediate signal and demodulates it into the original data and / or control signal.

3. The information transmission method according to claim 2, characterized in that: The first node device and the second node device are connected in a series structure or a parallel structure, the first node device serves as a master node, and the second node device serves as a slave node.

4. The information transmission method according to claim 3, characterized in that: The first node device and the second node device are connected in a series structure. The first node device modulates the original data and / or control signal current into a current signal as an intermediate signal to the bus through the PWM switching circuit, and the second node device samples the intermediate signal through the current and voltage sampling circuit and current demodulates it into the original data and / or control signal.

5. The information transmission method according to claim 3, characterized in that: The first node device and the second node device are connected in a series structure. The second node device modulates the original data and / or control signal voltage into a voltage signal as an intermediate signal to the bus through the PWM switching circuit, and the first node device samples the intermediate signal through the current and voltage sampling circuit and demodulates the voltage into the original data and / or control signal.

6. The information transmission method according to claim 3, characterized in that: The first node device and the second node device are connected in a parallel structure. The first node device modulates the original data and / or control signal voltage into a voltage signal as an intermediate signal to the bus through the PWM switching circuit, and the second node device samples the intermediate signal through the current and voltage sampling circuit and demodulates the voltage into the original data and / or control signal.

7. The information transmission method according to claim 3, characterized in that: The first node device and the second node device are connected in a parallel structure. The second node device modulates the original data and / or control signal current into a current signal as an intermediate signal to the bus through the PWM switching circuit, and the first node device samples the intermediate signal through the current and voltage sampling circuit and current demodulates it into the original data and / or control signal.

8. An information transmission method according to any one of claims 4 to 7, characterized in that: The control signal includes a synchronization header, a peak current, a peak voltage and a reference time.

9. An information transmission method according to claim 8, characterized in that: Take the peak current as the maximum value and divide the maximum value into n equal parts. n can be selected as 1, 2, 3, 4...

16.

10. An information transmission system, wherein the system is used to implement an information transmission method according to any one of claims 1 to 9.

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