Time synchronization method, device and storage medium

Abstract

The present application discloses a time synchronization method, which is applied to a PLC network including a head-end node and at least one tail-end node connected to the head-end node. The method includes: the head-end node generates data on voltage zero crossings based on a reference time, including the zero crossing time of the voltage zero crossing; when a first timing time arrives, the head-end node sends a first message including a timestamp of the first zero crossing to the tail-end node, the first zero crossing being the voltage zero crossing closest to the first timing time, and the timestamp of the first zero crossing is used by the tail-end node to determine the zero crossing time of the second zero crossing. The embodiments of the present application also provide corresponding equipment and storage media. In the technical solution of the present application, different nodes in the PLC network can achieve precise time synchronization by utilizing the consistency and periodicity of the voltage zero point generation, thereby ensuring that each node in the PLC network can maintain precise time synchronization and avoiding the occurrence of inconsistent data cycles in the synchronously collected data.

Description

Technical Field

[0001] The present invention relates to the technical field of power line communications, and in particular to a time synchronization method, device and storage medium. Background Art

[0002] With the development of the Power Internet of Things (PoI), the use of power line communication (PLC) has expanded from meter communication units to IoT communication units. In the Power Internet of Things (PoI), devices in the PLC network need to simultaneously record and broadcast waveform data of electrical quantities such as current and voltage. Domestic AC power frequency is 50Hz, and one AC cycle is 20ms. This requires that the devices involved in data collection in the PLC network support time synchronization. The time synchronization accuracy must ensure that power quality data collected at the same time by different nodes in the same substation is of the same cycle, thus avoiding errors in current quality judgment.

[0003] Existing technologies, such as the technical specifications for the data link layer communication protocol section of the "Technical Specifications for Interoperability of Low-Voltage Power Line Broadband Carrier Communications" issued by the State Grid Corporation of China, do not clearly define the time synchronization implementation methods and time accuracy of the tail nodes in the PLC network, as long as the necessary timing requirements are met. Therefore, in current PLC networks, the time synchronization accuracy and accuracy between the central coordinator (CCO) at the PLC headend, the proxy coordinator (PCO) at the PLC tailend, and the stations (STA) vary from manufacturer to manufacturer, and some products have poor synchronization accuracy. The larger the PLC network, the longer the synchronization time, the more layers the PLC network has, and the greater the error, even reaching the millisecond level. Therefore, how to solve the problem of poor time synchronization accuracy among products from different manufacturers, so that each node in the PLC network can maintain precise time synchronization and avoid inconsistent frequency representation of the synchronously collected data, is an urgent problem to be solved. Summary of the Invention

[0004] The embodiment of the present application provides a time synchronization method that can achieve accurate time synchronization between different nodes in a PLC network, thereby ensuring that each node in the PLC network can maintain accurate time synchronization and avoiding the occurrence of inconsistent data cycles in synchronous collection.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] In a first aspect, the present application provides a time synchronization method, which is applied to a PLC network. The PLC network includes a headend node and at least one tailend node connected to the headend node. The headend node may be a CCO, and the at least one tailend node may include one or more PCOs, or one or more STAs. Both the headend node and the tailend node have the function of detecting voltage zero crossings. Specifically, voltage zero crossing detection can be achieved by adding voltage zero crossing detection circuits to the headend node and the tailend node, respectively. In this method, the headend node generates voltage zero crossing data based on a reference time, the voltage zero crossing data including the voltage zero crossing time. The headend node sends this voltage zero crossing data to the tailend node, so that the tailend node can determine the voltage zero crossing time of the tailend node based on the zero crossing time. Specifically, the time synchronization method includes: the headend node generates voltage zero crossing data based on a reference time, the voltage zero crossing data including the voltage zero crossing time. The reference time may be Coordinated Universal Time, also known as Universal Time, World Standard Time, or International Coordinated Time, which is the accurate time at the current moment. The head-end node generates data on voltage zero crossings based on the reference time, which is a continuous process. That is, the head-end node generates corresponding data based on the reference time at each voltage zero crossing. The present application can determine the first timing time based on the scale of the PLC network. The first timing time can be a multiple of 1ms. For example, under the condition of a domestic AC power frequency of 50Hz, the first timing time can be set to 200 zero voltage crossings. When the first timing time arrives, the head-end node sends a first message to the tail-end node. The first message can be a central beacon. The first message includes the timestamp of the first zero crossing. The timestamp of the first zero crossing is the zero crossing time with the smallest time interval between the voltage zero crossing time and the first timing time. That is, the first zero crossing is the zero crossing time closest to the first timing time. The first message can be a central beacon. That is, the head-end node can send the timestamp of the nearest voltage zero crossing to the tail-end node via the central beacon when the first timing time arrives. The tail-end node can be a PCO adjacent to the head-end node or a STA adjacent to the head-end node. Driven by the zero-crossing voltage detection circuit, the tail node continuously generates the zero-crossing time of each voltage zero-crossing. After receiving the first message sent by the head node, the tail node extracts the timestamp of the first zero-crossing from the first message and then determines the zero-crossing time of the second zero-crossing generated by the local node based on the timestamp of the first zero-crossing.

[0007] From the first aspect above, it can be seen that the head-end node sends the timestamp of the nearest voltage zero-crossing point to the tail-end node at regular intervals, so that after receiving the timestamp of the nearest voltage zero-crossing point, the tail-end node corrects the zero-crossing time of the locally generated voltage zero-crossing point, thereby enabling different nodes in the PLC network to achieve precise time synchronization between different nodes based on the consistency and periodicity of the voltage zero point generation, thereby ensuring that each node in the PLC network can maintain precise time synchronization and avoid the occurrence of inconsistent data cycles in the synchronous collection.

[0008] In combination with the above-mentioned first aspect, in the first possible implementation method of the first aspect, the second zero crossing point is the same voltage zero crossing point as the first zero crossing point. After receiving the first information, the tail node immediately modifies the zero crossing time of the first zero crossing point generated at this end to the zero crossing time of the first zero crossing point contained in the received first information. When subsequent voltage zero crossings are generated, the zero crossing time of each voltage zero crossing point is generated based on the zero crossing time of the updated first zero crossing point.

[0009] From the first possible implementation method of the first aspect mentioned above, it can be seen that the head-end node sends the timestamp of the nearest voltage zero-crossing point to the tail-end node at regular intervals, so that after receiving the timestamp of the nearest voltage zero-crossing point, the tail-end node immediately corrects the zero-crossing time of the nearest voltage zero-crossing point generated locally, thereby enabling different nodes in the PLC network to timely achieve precise time synchronization between different nodes based on the consistency and periodicity of the voltage zero point generation, thereby ensuring the efficiency of the nodes in the PLC network to achieve precise time synchronization.

[0010] In conjunction with the first aspect or the first possible implementation of the first aspect, in the second possible implementation of the first aspect, if the crystal oscillators used in the head-end node and the tail-end node are of low quality, in addition to the error in the zero-crossing time between the head-end node and the tail-end node, there may also be a false detection of the zero-crossing count value. Therefore, the voltage zero-crossing data generated by the head-end node based on the reference time may also include the zero-crossing count value of the voltage zero-crossing, and the tail-end node may determine the zero-crossing count value of the voltage zero-crossing generated by the tail-end node based on the zero-crossing count value of the voltage zero-crossing generated by the head-end node. Specifically, the first information sent by the head-end node to the tail-end node may also include the zero-crossing count value of the first zero-crossing. After receiving the first information sent by the head-end node, the tail-end node extracts the timestamp and zero-crossing count value of the first zero-crossing from the first information, and then determines the zero-crossing time and zero-crossing count value of the second zero-crossing based on the timestamp and zero-crossing count value of the first zero-crossing.

[0011] From the second possible implementation method of the first aspect above, it can be seen that the head-end node can carry the zero-crossing count value of the first zero-crossing point in the first information sent to the tail-end node, so that when the quality of the crystal oscillators used in the head-end node and the tail-end node is not high, the tail-end node can correct the zero-crossing count value of the generated second zero-crossing point, thereby further improving the accuracy of precise time synchronization between different nodes in the PLC network.

[0012] In conjunction with the second possible implementation of the first aspect, in a third possible implementation of the first aspect, when the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point. That is, when the second zero-crossing point is the same voltage zero-crossing point as the first zero-crossing point, the tail node will modify the zero-crossing count value of the first zero-crossing point already generated by the local end to the zero-crossing count value of the first zero-crossing point contained in the received first information.

[0013] In combination with the above-mentioned first aspect and any one of the first to third possible implementation methods of the first aspect, in the fourth possible implementation method of the first aspect, the local time refers to the current time recorded locally by the device of the tail node. The local time may deviate from the reference time. The tail node can calibrate the local time based on the timestamp of the first zero crossing point.

[0014] From the fourth possible implementation method of the first aspect above, it can be seen that the tail node can also calibrate the local time according to the timestamp of the voltage zero crossing point sent by the head node, so that the local time of the tail node can be accurately synchronized with the reference time.

[0015] In conjunction with the above-mentioned first aspect, any one of the first to fourth possible implementations of the first aspect, in the first aspect, in the fifth possible implementation, the head end node can also be connected to one or more terminal devices, and the terminal device and the head end node can be connected via a universal asynchronous receiver / transmitter (UART) serial port. The head end node generates the data of the voltage zero crossing according to the reference time, and the data of the voltage zero crossing includes the zero crossing time of the voltage zero crossing. The head end node sends the data of the voltage zero crossing to the terminal device connected thereto, so that the terminal device can determine the zero crossing time of the voltage zero crossing of the terminal device according to the zero crossing time. Specifically, after the head end node generates the data of the voltage zero crossing according to the reference time, when the second timing arrives, the head end node sends the second information to the terminal device, and the head end node can be sending the second information to the first terminal device via the UART serial port. The second timing can be the same as or different from the first timing. The second information includes the timestamp of the third zero crossing, and the third zero crossing is the nearest adjacent voltage zero crossing to the second timing. After receiving the second information, the terminal device determines the zero-crossing time of the fourth zero-crossing point based on the timestamp of the third zero-crossing point carried in the second information.

[0016] From the fifth possible implementation method of the first aspect above, it can be seen that when the head-end node in the PLC network is also connected to a terminal device, the head-end node sends the timestamp of the nearest voltage zero-crossing point to the terminal device connected to it at regular intervals, so that after receiving the timestamp of the nearest voltage zero-crossing point, the terminal device corrects the zero-crossing time of the locally generated voltage zero-crossing point, thereby achieving precise time synchronization with the head-end node, ensuring that each node in the PLC network and the terminal device connected to it can maintain precise time synchronization, and avoiding the occurrence of inconsistent frequency of the synchronously collected data.

[0017] In combination with the fifth possible implementation of the first aspect above, in the sixth possible implementation of the first aspect, the data of the voltage zero crossing generated by the head-end node based on the reference time also includes the zero crossing count value of the voltage zero crossing. The second information sent by the head-end node to the terminal device connected thereto includes, in addition to the timestamp of the third zero crossing, the zero crossing count value of the third zero crossing. The terminal device determines the zero crossing count value of the fourth zero crossing based on the zero crossing count value of the third zero crossing. The fourth zero crossing can be a voltage zero crossing that is the same as the third zero crossing, or it can be a voltage zero crossing that is different from the third zero crossing. For example, the fourth zero crossing is the Nth voltage zero crossing generated after the third zero crossing. If the fourth zero crossing is the same voltage zero crossing as the third zero crossing, then after receiving the second information, the terminal device immediately modifies the zero crossing time of the third zero crossing already generated by the local end to the zero crossing time of the third zero crossing contained in the received second information. If the fourth zero-crossing point is a voltage zero-crossing point that is different from the third zero-crossing point, for example, the fourth zero-crossing point is the Nth voltage zero-crossing point after the third zero-crossing point, the first terminal device can, after receiving the second information, when the fourth zero-crossing point occurs, if the timestamp of the third zero-crossing point is T3, generate the time of the fourth zero-crossing point as T3+aN, where a is the time interval between the zero-crossing times of each two adjacent voltage zero-crossing points.

[0018] From the sixth possible implementation method of the first aspect above, it can be seen that when the head-end node and the terminal device do not share a crystal oscillator, or the quality of the crystal oscillator used is not high, the head-end node can carry the zero-crossing count value of the third zero-crossing point in the second information sent to the terminal device to enable the terminal device to correct the zero-crossing count value of the generated fourth zero-crossing point, thereby further improving the accuracy of precise time synchronization.

[0019] In conjunction with the fifth or sixth possible implementation of the first aspect, in the seventh possible implementation of the first aspect, the timestamp of the third zero-crossing point is further used by the terminal device to calibrate the local time. Specifically, the local time of the terminal device refers to the current time recorded locally on the terminal device. This local time may deviate from the reference time. The terminal device can calibrate the local time based on the timestamp of the third zero-crossing point.

[0020] In conjunction with the first aspect and any one of the first to seventh possible implementations of the first aspect, in the eighth possible implementation of the first aspect, before the headend node generates voltage zero-crossing data based on the reference time, the process further includes: the headend node obtaining the reference time. The headend node may obtain the reference time from an upstream device, such as a management node or a clock source such as GPS or BeiDou. The headend node may obtain the reference time from the upstream device periodically or periodically.

[0021] From the eighth possible implementation method of the first aspect above, it can be seen that the head-end node can obtain the reference time periodically or regularly, and then generate voltage zero-crossing data based on the reference time to achieve precise time synchronization with the tail-end node, thereby ensuring that the time of different nodes in the PLC network can be aligned with the reference time.

[0022] A second aspect of the present application provides a time synchronization method, which is applied to a PLC network, the PLC network including a head-end node and at least one tail-end node connected to the head-end node. The head-end node may be a CCO, and the at least one tail-end node may include one or more PCOs, or one or more STAs. Both the head-end node and the tail-end node have the function of detecting voltage zero crossings. Specifically, the detection of voltage zero crossings can be achieved by adding voltage zero crossing detection circuits to the head-end node and the tail-end node, respectively. In this method, the head-end node generates a zero crossing time of the voltage zero crossing based on a reference time, and a first tail-end node receives the voltage zero crossing time sent by the head-end node, so that the first tail-end node can determine the zero crossing time of the voltage zero crossing of the tail-end node based on the zero crossing time. Specifically, the first tail-end node receives first information sent by the head-end node when a first timing time arrives, the first information including a timestamp of the first zero crossing, which is the zero crossing time of the voltage zero crossing closest to the zero crossing time of the voltage zero crossing generated by the head-end node based on the reference time when the first timing time arrives. The first information may be a central beacon, i.e., the head-end node may transmit the timestamp of the nearest voltage zero crossing to the first tail-end node via the central beacon upon arrival of the first timing. Driven by the zero-crossing voltage detection circuit, the first tail-end node also continuously generates the zero-crossing time of each voltage zero crossing. Upon receiving the first information sent by the head-end node, the first tail-end node extracts the timestamp of the first zero crossing from the first information and then determines the zero-crossing time of the second zero crossing generated locally based on the timestamp of the first zero crossing.

[0023] From the second aspect above, it can be seen that the head-end node sends the timestamp of the nearest voltage zero-crossing point to the tail-end node at regular intervals, so that after receiving the timestamp of the nearest voltage zero-crossing point, the tail-end node corrects the zero-crossing time of the locally generated voltage zero-crossing point, thereby enabling different nodes in the PLC network to achieve precise time synchronization between different nodes based on the consistency and periodicity of the voltage zero point generation, thereby ensuring that each node in the PLC network can maintain precise time synchronization and avoid the occurrence of inconsistent data cycles in the synchronous collection.

[0024] In conjunction with the above-mentioned second aspect, in a first possible implementation of the second aspect, when the first zero-crossing point and the second zero-crossing point are the same, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point. Specifically, the second zero-crossing point is the same voltage zero-crossing point as the first zero-crossing point. After receiving the first information, the tail node immediately modifies the zero-crossing time of the first zero-crossing point already generated by the local end to the zero-crossing time of the first zero-crossing point contained in the received first information. When a subsequent voltage zero-crossing point is generated, the zero-crossing time of each voltage zero-crossing point is generated based on the updated zero-crossing time of the first zero-crossing point.

[0025] From the first possible implementation method of the second aspect mentioned above, it can be seen that the head-end node sends the timestamp of the nearest voltage zero-crossing point to the first tail-end node at regular intervals, so that after receiving the timestamp of the nearest voltage zero-crossing point, the first tail-end node immediately corrects the zero-crossing time of the locally generated nearest voltage zero-crossing point, thereby enabling different nodes in the PLC network to timely achieve precise time synchronization between different nodes based on the consistency and periodicity of the voltage zero point generation, thereby ensuring the efficiency of the nodes in the PLC network to achieve precise time synchronization.

[0026] In combination with the above-mentioned second aspect or the first possible implementation of the second aspect, in the second possible implementation of the second aspect, when the quality of the crystal oscillator used in the head-end node and the first tail-end node is not high, in addition to the error in the zero-crossing time between the head-end node and the first tail-end node, there may also be a misdetection of the zero-crossing count value. Therefore, the voltage zero-crossing data generated by the head-end node based on the reference time can also include the zero-crossing count value of the voltage zero-crossing. Specifically, the first information also includes the zero-crossing count value of the first zero-crossing. After receiving the first information sent by the head-end node when the first timing time arrives, the first tail-end node extracts the timestamp and zero-crossing count value of the first zero-crossing from the first information, and then determines the zero-crossing time and zero-crossing count value of the second zero-crossing based on the timestamp and zero-crossing count value of the first zero-crossing.

[0027] From the second possible implementation method of the second aspect above, it can be seen that the head-end node can carry the zero-crossing count value of the first zero-crossing point in the first information sent to the first tail-end node, so that when the quality of the crystal oscillator used in the head-end node and the first tail-end node is not high, the first tail-end node can correct the zero-crossing count value of the generated second zero-crossing point, thereby further improving the accuracy of precise time synchronization between different nodes in the PLC network.

[0028] In conjunction with the second possible implementation of the second aspect, in a third possible implementation of the second aspect, when the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point. Specifically, when the second zero-crossing point is the same voltage zero-crossing point as the first zero-crossing point, the tail node will modify the zero-crossing count value of the first zero-crossing point already generated by the local end to the zero-crossing count value of the first zero-crossing point contained in the received first information.

[0029] In combination with the above-mentioned second aspect and any possible implementation of the first to third aspects of the second aspect, in a fourth possible implementation of the second aspect, after the first tail-end node receives the first information sent by the head-end node when the first timing time arrives, the method further includes: the tail-end node calibrating the local time based on the timestamp of the first zero-crossing point. Specifically, the local time refers to the current time recorded locally by the device of the tail-end node. This local time may deviate from the reference time. The tail-end node can calibrate the local time based on the timestamp of the first zero-crossing point.

[0030] From the fourth possible implementation method of the second aspect above, it can be seen that the first tail node can also calibrate the local time according to the timestamp of the voltage zero crossing point sent by the head node, so that the local time of the first tail node can be accurately synchronized with the reference time.

[0031] In conjunction with above-mentioned second aspect, second aspect first to 4 in any one possible implementation, in second aspect 5th possible implementation, the first tail end node is connected with one or more terminal equipments.Can be to be connected by universal asynchronous receiver / transmitter UART serial port between the first tail end node and the terminal equipment.After realizing the accurate time synchronization between the first tail end node and the head end node, can generate the zero crossing time of voltage zero crossing according to the timestamp of the second zero crossing, the first tail end node sends the data of this voltage zero crossing to the terminal equipment connected thereto, so that terminal equipment can determine the zero crossing time of the voltage zero crossing of this terminal equipment according to this zero crossing time. Specifically, after the first tail end node determines the zero-crossing time of the second zero-crossing point based on the timestamp of the first zero-crossing point, the method further includes: the first tail end node generates voltage zero-crossing data based on the zero-crossing time of the second zero-crossing point, the voltage zero-crossing data including the zero-crossing time of the voltage zero-crossing point; when the second timing time arrives, the first tail end node sends second information to the terminal device, the second information including the timestamp of the third zero-crossing point, the timestamp of the third zero-crossing point being the zero-crossing time of the voltage zero-crossing point generated by the first tail end node based on the zero-crossing time of the second zero-crossing point, the zero-crossing time with the smallest time interval with the second timing time, that is, the third zero-crossing point is the voltage zero-crossing point closest to the second timing time. The terminal device determines the zero-crossing time of the fourth zero-crossing point based on the timestamp of the third zero-crossing point.

[0032] From the fifth possible implementation method of the second aspect above, it can be seen that when the tail node in the PLC network is also connected to a terminal device, the terminal device connected to the tail node in the PLC network can also achieve precise time synchronization with the tail node based on the consistency and periodicity generated by the voltage point zero point, thereby ensuring that each node in the PLC network and the terminal device connected to it can maintain precise time synchronization, avoiding the occurrence of inconsistent data cycles in the synchronous collection.

[0033] In combination with the fifth possible implementation method of the second aspect mentioned above, in the sixth possible implementation method of the second aspect, the data of the voltage zero crossing also includes the zero crossing count value of the voltage zero crossing, and the second information also includes the zero crossing count value of the third zero crossing, and the terminal device determines the zero crossing count value of the fourth zero crossing based on the zero crossing count value of the third zero crossing.

[0034] In combination with the fifth or sixth possible implementation of the second aspect, in a seventh possible implementation of the second aspect, the terminal device calibrates the local time according to the timestamp of the third zero-crossing point.

[0035] In conjunction with the fifth possible implementation of the second aspect, in the eighth possible implementation of the second aspect, the first tail end node is further connected to a second tail end node. After achieving precise time synchronization with the head end node, the first tail end node generates data on the voltage zero crossing according to the timestamp of the second zero crossing. The first tail end node sends the data on the voltage zero crossing to the second tail end node connected thereto, so that the second tail end node can determine the zero crossing time of the voltage zero crossing of the second tail end node based on the zero crossing time. Specifically, after the first tail end node generates the data on the voltage zero crossing according to the zero crossing time of the second zero crossing, when the third timing time arrives, the first tail end node sends the third information to the second tail end node. The third timing time may be the same as at least one of the first timing time and the second timing time, or it may be different from both the first timing time and the second timing time. The third information includes a timestamp of a fifth zero-crossing point. The timestamp of the fifth zero-crossing point is the zero-crossing time of the voltage zero-crossing point generated by the first tail-end node based on the zero-crossing time of the second zero-crossing point, and is the zero-crossing time with the smallest time interval from the third timing time. That is, the fifth zero-crossing point is the closest voltage zero-crossing point generated closest to the third timing time. The second tail-end node determines the zero-crossing time of the sixth zero-crossing point based on the timestamp of the fifth zero-crossing point.

[0036] In conjunction with the eighth possible implementation of the second aspect, in a ninth possible implementation of the second aspect, after the first tail-end node achieves precise time synchronization with the head-end node, the voltage zero-crossing data generated by the first tail-end node also includes a zero-crossing count value of the voltage zero-crossing. In the event that the crystal oscillators used in the first tail-end node and the second tail-end node are of low quality, the third information sent by the first tail-end node to the second tail-end node also includes a zero-crossing count value of a fifth zero-crossing, and the zero-crossing count value of the fifth zero-crossing is used by the second tail-end node to determine a zero-crossing count value of a sixth zero-crossing.

[0037] A third aspect of the present application provides a time synchronization method, which is applied to a PLC network, wherein the PLC network includes a head-end node and at least one tail-end node connected to the head-end node, and at least one of the head-end node and the at least one tail-end node is connected to at least one terminal device. The head-end node may be a CCO, and the at least one tail-end node may include one or more PCOs, or one or more STAs. Both the head-end node and the tail-end node have the function of detecting the voltage zero crossing point. Specifically, the detection of the voltage zero crossing point can be achieved by adding a voltage zero crossing detection circuit to the head-end node and the tail-end node respectively. In this method, the head-end node or the tail-end node generates data on the voltage zero crossing point, and the voltage zero crossing data includes the zero crossing time of the voltage zero crossing point. The head-end node or the tail-end node sends the voltage zero crossing data to the terminal device connected thereto, so that the terminal device can determine the zero crossing time of the voltage zero crossing of the terminal device based on the zero crossing time. Specifically, the method includes: the terminal device receives the first information sent by the first node when the first timing time arrives, the first information includes the timestamp of the first zero-crossing point, and the timestamp of the first zero-crossing point is the zero-crossing time of the voltage zero-crossing point generated by the first node with the smallest time interval with the first timing time; the terminal device determines the timestamp of the second zero-crossing point based on the timestamp of the first zero-crossing point.

[0038] From the third aspect above, it can be seen that when the head-end node or the tail-end node in the PLC network is connected to a terminal device, the head-end node or the tail-end node sends the timestamp of the nearest voltage zero-crossing point to the terminal device connected to it at regular intervals, so that after receiving the timestamp of the nearest voltage zero-crossing point, the terminal device corrects the zero-crossing time of the locally generated voltage zero-crossing point, thereby achieving precise time synchronization with the head-end node or the tail-end node, thereby ensuring that each node in the PLC network and the terminal device connected to it can maintain precise time synchronization, avoiding the occurrence of inconsistent frequency of the synchronously collected data.

[0039] In conjunction with the third aspect described above, in a first possible implementation of the third aspect, when the first node is a headend node, the zero-crossing time of the voltage zero-crossing is generated by the first node based on a reference time. Specifically, the headend node generates voltage zero-crossing data based on the reference time, where the voltage zero-crossing data includes the zero-crossing time of the voltage zero-crossing. The headend node transmits the voltage zero-crossing data to a connected terminal device, allowing the terminal device to determine the zero-crossing time of the voltage zero-crossing of the terminal device based on the zero-crossing time. This achieves precise time synchronization between the headend node and the terminal device.

[0040] In combination with the above-mentioned third aspect, in the second possible implementation method of the third aspect, when the first node is a tail node, the zero-crossing time of the voltage zero-crossing point is generated by the first node based on the timestamp of the third zero-crossing point, and the timestamp of the third zero-crossing point is sent by the second node to the first node when the second timing time arrives. The timestamp of the third zero-crossing point is the zero-crossing time with the smallest time interval between the timestamp of the voltage zero-crossing point generated by the second node and the second timing time. Specifically, the tail node generates data on the voltage zero-crossing point after achieving precise time synchronization with the head node. The data on the voltage zero-crossing point includes the zero-crossing time of the voltage zero-crossing point. The tail node sends the data on the voltage zero-crossing point to the terminal device connected thereto, so that the terminal device can determine the zero-crossing time of the voltage zero-crossing point of the terminal device based on the zero-crossing time. Thereby, precise time synchronization between the tail node and the terminal device is achieved.

[0041] In combination with the above-mentioned third aspect and any possible implementation method from the first to the second of the third aspect, in the third possible implementation method of the third aspect, the first information also includes the zero-crossing count value of the first zero-crossing point, and the method also includes: the terminal device determines the zero-crossing count value of the second zero-crossing point based on the zero-crossing count value of the first zero-crossing point.

[0042] In combination with the above-mentioned third aspect and any possible implementation method of the first to third aspects of the third aspect, in the fourth possible implementation method of the third aspect, after the terminal device receives the first information sent by the first node when the first timing time arrives, it also includes: the terminal device calibrates the local time according to the timestamp of the first zero-crossing point.

[0043] A fourth aspect of the present application provides a network device, which is applied to a PLC network. The network device is a head-end node, and the PLC network also includes at least one tail-end node connected to the head-end node. The network device includes: a generation unit, which is used to generate voltage zero-crossing data based on a reference time, and the voltage zero-crossing data includes the zero-crossing time of the voltage zero-crossing; a sending unit, which is used to send first information to the tail-end node when a first timing time arrives, and the first information includes a timestamp of the first zero-crossing. The timestamp of the first zero-crossing is the zero-crossing time of the voltage zero-crossing generated by the generation unit with the smallest time interval with the first timing time. The timestamp of the first zero-crossing is used by the tail-end node to determine the zero-crossing time of the second zero-crossing.

[0044] In combination with the above-mentioned fourth aspect, in a first possible implementation manner of the fourth aspect, when the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point.

[0045] In combination with the above-mentioned fourth aspect or the first possible implementation method of the fourth aspect, in the second possible implementation method of the fourth aspect, the data of the voltage zero crossing also includes the zero crossing count value of the voltage zero crossing, and the first information also includes the zero crossing count value of the first zero crossing, and the zero crossing count value of the first zero crossing is used by the tail node to determine the zero crossing count value of the second zero crossing.

[0046] In combination with the second possible implementation method of the fourth aspect above, in a third possible implementation method of the fourth aspect, when the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point.

[0047] In combination with the above-mentioned fourth aspect and any one of the first to third possible implementation methods of the fourth aspect, in the fourth possible implementation method of the fourth aspect, the timestamp of the first zero-crossing point is also used by the tail node to calibrate the local time.

[0048] In combination with the above-mentioned fourth aspect and any one of the first to fourth possible implementation methods of the fourth aspect, in the fifth possible implementation method of the fourth aspect, the network device is connected to the terminal device, and the sending unit is also used to send second information to the terminal device when the second timing time arrives after the generating unit generates the data of the voltage zero crossing point according to the reference time. The second information includes the timestamp of the third zero crossing point. The timestamp of the third zero crossing point is the zero crossing time of the voltage zero crossing point with the smallest time interval with the second timing time. The timestamp of the third zero crossing point is used by the terminal device to determine the zero crossing time of the fourth zero crossing point.

[0049] In combination with the fifth possible implementation method of the fourth aspect mentioned above, in the sixth possible implementation method of the fourth aspect, the data of the voltage zero crossing also includes the zero crossing count value of the voltage zero crossing, and the second information also includes the zero crossing count value of the third zero crossing, and the zero crossing count value of the third zero crossing is used by the terminal device to determine the zero crossing count value of the fourth zero crossing.

[0050] In combination with the fifth or sixth possible implementation of the fourth aspect above, in the seventh possible implementation of the fourth aspect, the timestamp of the third zero-crossing point is also used by the terminal device to calibrate the local time.

[0051] In combination with the above-mentioned fourth aspect and any one of the first to seventh possible implementation methods of the fourth aspect, in the eighth possible implementation method of the fourth aspect, the network device also includes: an acquisition unit, used to obtain the reference time before the generation unit generates the data of the voltage zero crossing point based on the reference time.

[0052] The fifth aspect of the present application provides a network device, characterized in that the network device is applied to a PLC network, the network device is a first tail node, the PLC network also includes a head node connected to the first tail node, and the network device includes: a receiving unit, used to receive a first information sent by the head node when a first timing time arrives, the first information includes a first zero-crossing timestamp, the first zero-crossing timestamp is the zero-crossing time of the voltage zero-crossing generated by the head node according to the reference time, and the zero-crossing time with the shortest interval time with the first timing time; a determination unit, used to determine the zero-crossing time of the second zero-crossing based on the first zero-crossing times in the first information received by the receiving unit.

[0053] In combination with the above-mentioned fifth aspect, in a first possible implementation manner of the fifth aspect, when the first zero-crossing point and the second zero-crossing point are the same, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point.

[0054] In combination with the above-mentioned fifth aspect or the first possible implementation method of the fifth aspect, in the second possible implementation method of the fifth aspect, the first information also includes the zero-crossing count value of the first zero-crossing point, and the determination unit is also used to determine the zero-crossing count value of the second zero-crossing point based on the zero-crossing count value of the first zero-crossing point after the receiving unit receives the first information sent by the head-end node when the first timing time arrives.

[0055] In combination with the second possible implementation method of the above-mentioned fifth aspect, in a third possible implementation method of the fifth aspect, when the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point.

[0056] In combination with the above-mentioned fifth aspect and any one of the first to third possible implementation methods of the fifth aspect, in the fourth possible implementation method of the fifth aspect, the network device also includes: a calibration unit, which is used to calibrate the local time according to the timestamp of the first zero-crossing point after the receiving unit receives the first information sent by the head-end node when the first timing time arrives.

[0057] In combination with the above-mentioned fifth aspect and any one of the first to fourth possible implementation methods of the fifth aspect, in the fifth possible implementation method of the fifth aspect, the first tail node is connected to the terminal device, and the network device also includes: a generating unit, which is used to generate voltage zero-crossing data according to the zero-crossing time of the second zero-crossing point after the determining unit determines the zero-crossing time of the second zero-crossing point according to the timestamp of the first zero-crossing point, and the voltage zero-crossing data includes the zero-crossing time of the voltage zero-crossing point; a sending unit, which is used to send second information to the terminal device when the second timing time arrives, and the second information includes the timestamp of the third zero-crossing point. The timestamp of the third zero-crossing point is the zero-crossing time of the voltage zero-crossing point generated by the generating unit with the smallest time interval with the second timing time, and the timestamp of the third zero-crossing point is used by the terminal device to determine the zero-crossing time of the fourth zero-crossing point.

[0058] In combination with the fifth possible implementation method of the above-mentioned fifth aspect, in the sixth possible implementation method of the fifth aspect, the data of the voltage zero crossing also includes the zero crossing count value of the voltage zero crossing, and the second information also includes the zero crossing count value of the third zero crossing, and the zero crossing count value of the third zero crossing is used by the terminal device to determine the zero crossing count value of the fourth zero crossing.

[0059] In combination with the fifth or sixth possible implementation of the fifth aspect above, in the seventh possible implementation of the fifth aspect, the timestamp of the third zero-crossing point is also used by the terminal device to calibrate the local time.

[0060] In combination with the fifth possible implementation method of the fifth aspect above, in the eighth possible implementation method of the fifth aspect, the sending unit is also used to send third information to the second tail end node when the third timing time arrives, and the third information includes the timestamp of the fifth zero crossing point. The timestamp of the fifth zero crossing point is the zero crossing time of the voltage zero crossing point generated by the generating unit, and the zero crossing time with the smallest time interval with the third timing time. The timestamp of the fifth zero crossing point is used by the second tail end node to determine the zero crossing time of the sixth zero crossing point.

[0061] In combination with the eighth possible implementation method of the above-mentioned fifth aspect, in the ninth possible implementation method of the fifth aspect, the data of the voltage zero crossing also includes the zero crossing count value of the voltage zero crossing, and the third information also includes the zero crossing count value of the fifth zero crossing, and the zero crossing count value of the fifth zero crossing is used by the second tail node to determine the zero crossing count value of the sixth zero crossing.

[0062] In a sixth aspect of the present application, there is provided a terminal device, which is applied to a PLC network. The PLC network includes a head-end node and at least one tail-end node connected to the head-end node. At least one of the head-end node and the at least one tail-end node is connected to at least one terminal device. The terminal device includes: a receiving unit, which is used to receive a first message sent by a first node when a first timing time arrives, the first message including a timestamp of a first zero-crossing point, which is a zero-crossing time of a voltage zero-crossing point generated by the first node with the shortest time interval with the first timing time; and a determining unit, which is used to determine a timestamp of a second zero-crossing point based on the timestamp of the first zero-crossing point in the first message received by the receiving unit.

[0063] In combination with the above-mentioned sixth aspect, in a first possible implementation manner of the sixth aspect, when the first node is a head-end node, the zero-crossing time of the voltage zero-crossing point is generated by the first node according to the reference time.

[0064] In combination with the above-mentioned sixth aspect, in the second possible implementation method of the sixth aspect, when the first node is the tail node, the zero-crossing time of the voltage zero-crossing is generated by the first node based on the timestamp of the third zero-crossing, and the timestamp of the third zero-crossing is sent by the second node to the first node when the second timing time arrives, and the timestamp of the third zero-crossing is the zero-crossing time with the smallest time interval between the timestamp of the voltage zero-crossing generated by the second node and the second timing time.

[0065] In combination with the above-mentioned sixth aspect and any one of the first to second possible implementation methods of the sixth aspect, in the third possible implementation method of the sixth aspect, the first information also includes the zero-crossing count value of the first zero-crossing point, and the determination unit is also used to determine the zero-crossing count value of the second zero-crossing point based on the zero-crossing count value of the first zero-crossing point.

[0066] In combination with the above-mentioned sixth aspect and any one of the first to third possible implementation methods of the sixth aspect, in the fourth possible implementation method of the sixth aspect, the terminal device also includes: a calibration unit, which is used to calibrate the local time according to the timestamp of the first zero-crossing point after the receiving unit receives the first information sent by the first node when the first timing time arrives.

[0067] In a seventh aspect, the present application provides a network device comprising a processor and a memory. The memory is configured to store computer-readable instructions (or computer programs), and the processor is configured to read the computer-readable instructions to implement the methods provided in the aforementioned aspects related to the headend node and any implementation thereof.

[0068] In some implementations, the network device further includes a transceiver for receiving and sending data.

[0069] In an eighth aspect, the present application provides a network device comprising a processor and a memory. The memory is configured to store computer-readable instructions (or computer programs), and the processor is configured to read the computer-readable instructions to implement the methods provided in the aforementioned aspects related to the tail node and any implementation thereof.

[0070] In some implementations, the network device further includes a transceiver for receiving and sending data.

[0071] In a ninth aspect, the present application provides a terminal device comprising a processor and a memory. The memory is configured to store computer-readable instructions (or computer programs), and the processor is configured to read the computer-readable instructions to implement the methods provided in the aforementioned aspects of the terminal device and any implementation thereof.

[0072] In some implementations, the terminal device further includes a transceiver for receiving and sending data.

[0073] In a tenth aspect, the present application provides a device having the function of implementing the headend node behavior in the first aspect or any possible implementation of the first aspect, and including means for performing the steps or functions described in the first aspect or any possible implementation of the first aspect. The steps or functions can be implemented by software, hardware (such as a circuit), or a combination of hardware and software.

[0074] In one possible design, the apparatus includes one or more processors and a communication unit. The one or more processors are configured to support the apparatus in performing the corresponding functions of the headend node in the above method. The communication unit is configured to support the apparatus in communicating with other devices to implement receiving and / or transmitting functions.

[0075] Optionally, the device may further include one or more memories coupled to the processor to store program instructions and / or data necessary for the device. The one or more memories may be integrated with the processor or may be separate from the processor. This application is not limited thereto.

[0076] The device may be a PLC module, etc., and the communication unit may be a transceiver or a transceiver circuit. Optionally, the transceiver may also be an input / output circuit or an interface.

[0077] The device may also be a chip system. The communication unit may be an input / output circuit or an interface of the chip system.

[0078] In another possible design, the apparatus includes a transceiver, a processor, and a memory. The processor is configured to control the transceiver or input / output circuit to transmit and receive signals, the memory is configured to store a computer program, and the processor is configured to execute the computer program in the memory, so that the apparatus performs the method performed by the headend node in the first aspect or any possible implementation of the first aspect.

[0079] In an eleventh aspect of the present application, a device is provided, which has the function of implementing the tail node behavior in the second aspect or any possible implementation of the second aspect, and includes means for performing the steps or functions described in the second aspect or any possible implementation of the second aspect. The steps or functions can be implemented by software, hardware (such as a circuit), or a combination of hardware and software.

[0080] In one possible design, the apparatus includes one or more processors and a communication unit. The one or more processors are configured to support the apparatus in performing the functions corresponding to the tail node in the method. The communication unit is configured to support the apparatus in communicating with other devices to implement receiving and / or transmitting functions.

[0081] Optionally, the apparatus may further include one or more memories coupled to the processor to store program instructions and / or data necessary for the network device. The one or more memories may be integrated with the processor or may be separate from the processor. This application is not limited thereto.

[0082] The device may be a PLC module, and the communication unit may be a transceiver or a transceiver circuit. Optionally, the transceiver may also be an input / output circuit or an interface.

[0083] The device may also be a chip system. The communication unit may be an input / output circuit or an interface of the chip system.

[0084] In another possible design, the above-mentioned apparatus includes a transceiver, a processor, and a memory. The processor is used to control the transceiver or input / output circuit to transmit and receive signals, the memory is used to store a computer program, and the processor is used to execute the computer program in the memory, so that the apparatus performs the method performed by the tail node in the second aspect or any possible implementation of the second aspect.

[0085] The twelfth aspect of the present application provides a PLC communication system, which includes the above-mentioned head-end node and at least one tail-end node connected to the head-end node.

[0086] In combination with the twelfth aspect, in a first possible implementation of the twelfth aspect, the PLC communication system also includes the at least one terminal device mentioned above.

[0087] A thirteenth aspect of the present application provides a computer-readable storage medium for storing a computer program, wherein the computer program includes instructions for executing the method related to the head-end node in any possible implementation of the first aspect to the first aspect.

[0088] In a fourteenth aspect, the present application provides a computer-readable storage medium for storing a computer program, wherein the computer program includes instructions for executing the method related to the tail node in any possible implementation of the second aspect to the second aspect.

[0089] In a fifteenth aspect, the present application provides a computer-readable storage medium for storing a computer program, wherein the computer program includes instructions for executing a method related to a terminal device in any possible implementation of the third aspect to the third aspect.

[0090] In aspect 16 of the present application, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method related to the head-end node in any possible implementation of aspect 1 to aspect 1 above.

[0091] In aspect seventeen, the present application provides a computer program product, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method related to the tail node in any possible implementation of aspect two to aspect two above.

[0092] In an eighteenth aspect, the present application provides a computer program product, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method related to the terminal device in any possible implementation of the third aspect to the third aspect.

[0093] Among them, the technical effects brought about by any implementation method in the fourth aspect, seventh aspect, tenth aspect, thirteenth aspect, and sixteenth aspect can refer to the technical effects brought about by different implementation methods in the first aspect, and will not be repeated here.

[0094] Among them, the technical effects brought about by any implementation method in the fifth, eighth, eleventh, fourteenth and seventeenth aspects can be referred to the technical effects brought about by different implementation methods in the second aspect, and will not be repeated here.

[0095] Among them, the technical effects brought about by any implementation method in the sixth, ninth, fifteenth and eighteenth aspects can be referred to the technical effects brought about by different implementation methods in the third aspect, and will not be repeated here.

[0096] The embodiment of the present application adopts a time synchronization method, in which the head-end node periodically sends the timestamp of the nearest voltage zero-crossing point to the tail-end node, so that after receiving the timestamp of the nearest voltage zero-crossing point, the tail-end node corrects the zero-crossing time of the locally generated voltage zero-crossing point, so that different nodes in the PLC network can achieve precise time synchronization between different nodes based on the consistency and periodicity of the voltage zero point generation, thereby ensuring that each node in the PLC network can maintain precise time synchronization and avoid the occurrence of inconsistent data cycles in the synchronous collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] Figure 1 This is a schematic diagram of the structure of the power communication system provided by an embodiment of the present application;

[0098] Figure 2 This is a schematic diagram of an embodiment of the time synchronization method provided by the embodiment of the present application;

[0099] Figure 3 This is a schematic diagram of another embodiment of the time synchronization method provided in an embodiment of the present application;

[0100] Figure 4 This is a schematic diagram of the structure of the network device provided in the embodiment of the present application;

[0101] Figure 5 This is another structural diagram of the network device provided in an embodiment of the present application;

[0102] Figure 6 This is another structural diagram of the network device provided in an embodiment of the present application;

[0103] Figure 7 Schematic diagram of the structure of the PLC device provided in the embodiment of the present application;

[0104] Figure 8 This is a schematic diagram of the structure of the terminal device provided in an embodiment of the present application;

[0105] Figure 9 This is another structural diagram of the terminal device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0106] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the following describes the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. It is known to those skilled in the art that with the emergence of new application scenarios, the technical solutions provided by the embodiments of the present invention are also applicable to similar technical problems.

[0107] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules that are not clearly listed or that are inherent to these processes, methods, products or devices. The naming or numbering of steps in this application does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The process steps that have been named or numbered can be changed in the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved. The division of modules in this application is a logical division. In actual application, there may be other division methods. For example, multiple modules can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection between modules can be electrical or other similar forms, which are not limited in this application. Moreover, the modules or submodules described as separate components may or may not be physically separated, may or may not be physical modules, or may be distributed into multiple circuit modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this application.

[0108] Power line communication (PLC) is a specialized communication method that uses high-voltage power lines (35kV and above), medium-voltage power lines (10-30kV), or low-voltage distribution lines (380 / 220kV subscriber lines) as the information transmission medium. This technology transfers data by loading high-frequency signals carrying information onto the power lines. A dedicated power line modulator / demodulator (PLC) decouples the high-frequency signals from the power lines, achieving communication.

[0109] Figure 1 A schematic diagram of the structure of a power communication system provided in an embodiment of the present application.

[0110] like Figure 1 As shown, the power system includes a management node 10, one or more PLC networks 20, and one or more terminal devices 30. The management node 10 in the embodiment of the present application is used to obtain data within the one or more PLC networks 20 to which it is connected, thereby realizing the operation control and management of the power communication system. The management node 10 can refer to a distribution transformer supervisory terminal unit (TTU) or a management server of an e-commerce company. The management node 10 can be connected to the terminal device 30 through the PLC network 20 to obtain data information of the terminal device 30.

[0111] Each PLC network 20 includes a head-end node 40 and one or more tail-end nodes 50 connected to the head-end node 40 via electrical lines. Figure 1 A simple PLC network structure is shown in FIG. It is understandable that, in actual application, the PLC network 20 may also include other numbers of tail nodes 50, and the tail nodes 50 may be connected through one or more levels, which is not limited in the embodiment of the present application. The head node 40 in the PLC network 20 may be a central coordinator (CCO), and the multiple tail nodes may include one or more cascaded proxy coordinators (PCO), or one or more stations (STA), that is, the tail node 50 may be a PCO or a STA. In the PLC network 20, some STAs can be directly connected to the CCO, while some STAs cannot be directly connected to the CCO. The two are connected through one or more cascaded PCOs, and all messages between the CCO and the STA are forwarded by the one or more cascaded PCOs. When the tail node 50 is an STA, the STA is connected to at least one terminal device. The head-end node 40 or the tail-end node 50 may be connected to at least one terminal device 30 , or the head-end node 40 or the tail-end node 50 may not be connected to the terminal device 30 , which is not limited in the embodiment of the present application.

[0112] based on Figure 1 A PLC network in the present application provides a schematic diagram of an embodiment of a time synchronization method, as shown in FIG. Figure 2 shown.

[0113] See Figure 2 An embodiment of the time synchronization method provided in the embodiments of the present application may include:

[0114] 201. A head-end node generates voltage zero-crossing data according to a reference time. The voltage zero-crossing data includes a zero-crossing time of the voltage zero-crossing.

[0115] In the embodiments of the present application, both the head-end node and the tail-end node have the function of detecting voltage zero crossings. Specifically, in the embodiments of the present application, voltage zero crossing detection can be achieved by adding a voltage zero crossing detection circuit to each of the head-end node and the tail-end node. The voltage zero crossing detection circuit outputs a signal each time the voltage crosses zero, thereby driving the head-end node or the tail-end node to generate the zero crossing time of the voltage zero crossing each time the voltage crosses zero.

[0116] A voltage zero crossing refers to the point at which positive or negative direct current, such as pulse voltage, or alternating current with positive or negative amplitudes, must pass through zero. This point is called the voltage zero crossing. The voltage zero crossing is independent of the load on the line. The voltage only decreases with increasing transmission distance, but its phase and frequency do not change. This is because the inductive or capacitive characteristics of the line load do not affect the occurrence of voltage zero crossings in the line. Therefore, when detecting voltage zero crossings at any location on the same phase line, the same voltage zero crossing will occur simultaneously. The voltage zero crossing detection circuit is a mature, low-cost circuit design used to detect voltage zero crossings in lines and will not be described in detail here. The AC power we use in daily life generally has a frequency of 50Hz or 60Hz. For example, China and Europe use 50Hz AC power. Taking the single-phase voltage zero-crossing detection circuit for detecting the voltage zero-crossing point of 50Hz alternating current as an example, 50Hz alternating current will produce 100 voltage zero-crossing points per second, that is, the voltage of the same phase passes through zero voltage once every 10ms. Therefore, the voltage zero-crossing detection circuit generates a pulse signal every 10ms, thereby triggering the detection of voltage zero-crossing related data.

[0117] Optionally, in addition to the zero-crossing time of the voltage zero-crossing point, the zero-crossing detection circuit can also drive the head-end node or the tail-end node to count the voltage zero-crossing points each time the voltage zero-crossing point occurs. Specifically, taking the domestic 50Hz AC frequency as an example, a zero voltage will be generated once every 10ms in the line, that is, a voltage zero-crossing point will be generated. The head-end node or the tail-end node will generate corresponding voltage zero-crossing point data each time the voltage zero-crossing point occurs. It should be noted that for single-phase AC power, the voltage zero-crossing point data generated by the head-end node or the tail-end node includes the data of the corresponding voltage zero-crossing point of the single phase; for three-phase AC power, the voltage zero-crossing point data generated by the head-end node or the tail-end node includes the data of the corresponding voltage zero-crossing point of each of the three phases.

[0118] The reference time in the embodiments of the present application may refer to Coordinated Universal Time, also known as Universal Time, Standard World Time, or International Coordinated Time, which is the current accurate time. Optionally, in the embodiments of the present application, the headend node may obtain the reference time from an upstream device, such as a management node or a clock source such as GPS or BeiDou.

[0119] In the embodiment of the present application, the head-end node generates data on the voltage zero crossing based on the reference time, and the data on the voltage zero crossing includes the zero crossing time of the voltage zero crossing. In the embodiment of the present application, the head-end node generates data on the voltage zero crossing based on the reference time, which is a continuous process. That is, the head-end node generates corresponding data at each voltage zero crossing based on the reference time.

[0120] Optionally, in an embodiment of the present application, the voltage zero-crossing data generated by the head-end node according to the reference time may also include other information related to the voltage zero-crossing, such as a zero-crossing count value of the voltage zero-crossing.

[0121] Optionally, in an embodiment of the present application, the head-end node may periodically obtain a reference time, and after each reference time is obtained, generate a zero-crossing time of the voltage zero-crossing point based on the newly obtained reference time.

[0122] 202. When the first timing time arrives, the head-end node sends first information to the tail-end node, where the first information includes a timestamp of a first zero-crossing point. The timestamp of the first zero-crossing point is a zero-crossing point time with the smallest time interval between the voltage zero-crossing point time and the first timing time.

[0123] The first timing period in the embodiment of the present application can be determined based on the scale of the PLC network. The first timing period can be a multiple of 1ms. For example, under the condition of a domestic AC power frequency of 50Hz, the first timing period can be set to 200 zero-voltage crossings, that is, the period of the first timing period is 2s.

[0124] In an embodiment of the present application, after the head-end node generates data on the voltage zero crossing according to the reference time, when the first timing time arrives, the head-end node sends first information to the tail-end node, the first information including the timestamp of the first zero crossing. The timestamp of the first zero crossing is the zero crossing time with the smallest time interval between the zero crossing times of the voltage zero crossings generated by the head-end node according to the reference time and the first timing time. That is, the head-end node generates one or more zero crossing times corresponding to the voltage zero crossings according to the reference time, the first zero crossing being the voltage zero crossing closest to the arrival time of the first timing time. When the first timing time arrives, the head-end node sends the zero crossing timestamp of the most recently generated voltage zero crossing to the tail-end node.

[0125] In the embodiment of the present application, the first information may be a central beacon, that is, the head-end node sends the timestamp of the first zero-crossing point to the tail-end node via the central beacon.

[0126] 203. The tail end node determines a zero-crossing time of a second zero-crossing point according to the timestamp of the first zero-crossing point.

[0127] The tail node in the embodiment of the present application can be a PCO adjacent to the head node, or it can be an STA adjacent to the head node, and the embodiment of the present application does not limit this. In the embodiment of the present application, after receiving the first information sent by the head node, the tail node will extract the timestamp of the first zero crossing from the first information, and then determine the zero crossing time of the second zero crossing based on the timestamp of the first zero crossing.

[0128] Optionally, in an embodiment of the present application, if the crystal oscillators used in the head-end node and the tail-end node are of low quality and may result in false detection of the zero-crossing count value, the first information sent by the head-end node to the tail-end node may further include the zero-crossing count value of the first zero-crossing point. After receiving the first information sent by the head-end node, the tail-end node extracts the timestamp and zero-crossing count value of the first zero-crossing point from the first information, and then determines the zero-crossing time and zero-crossing count value of the second zero-crossing point based on the timestamp of the first zero-crossing point.

[0129] In the embodiment of the present application, the tail node also continuously generates the zero-crossing time of each voltage zero-crossing point under the drive of the zero-crossing voltage detection circuit. The second zero-crossing point can be the same voltage zero-crossing point as the first zero-crossing point, or it can be a voltage zero-crossing point different from the first zero-crossing point. For example, the second zero-crossing point is the Nth voltage zero-crossing point generated after the first zero-crossing point. The specific method for the tail node to determine the zero-crossing time of the second zero-crossing point based on the timestamp of the first zero-crossing point can be:

[0130] If the second zero crossing point is the same voltage zero crossing point as the first zero crossing point, the tail node will immediately modify the zero crossing time t1 of the first zero crossing point generated at this end to the zero crossing time T1 of the first zero crossing point contained in the received first information after receiving the first information. When subsequent voltage zero crossings occur, the zero crossing time of each voltage zero crossing point is generated based on the updated zero crossing time T1 of the first zero crossing point.

[0131] Optionally, if the first information also includes the zero-crossing count value M1 of the first zero-crossing point, when the second zero-crossing point is the same voltage zero-crossing point as the first zero-crossing point, the tail node will not only modify the zero-crossing time t1 of the first zero-crossing point generated at this end to the zero-crossing time T1 of the first zero-crossing point contained in the received first information, but will also modify the zero-crossing count value m1 of the first zero-crossing point generated at this end to the zero-crossing count value M1 of the first zero-crossing point contained in the received first information. When a subsequent voltage zero-crossing point occurs, based on the updated zero-crossing count value M1 of the first zero-crossing point, the count value is +1 each time a voltage zero-crossing point is generated.

[0132] If the second zero-crossing point is a voltage zero-crossing point different from the first zero-crossing point, for example, the second zero-crossing point is the Nth voltage zero-crossing point after the first zero-crossing point, after receiving the first information, when the second zero-crossing point occurs, if the timestamp of the first zero-crossing point is T1, the zero-crossing time of the second zero-crossing point is generated as T1+aN. When subsequent voltage zero-crossing points occur, the zero-crossing time of each voltage zero-crossing point is generated based on the zero-crossing time T1+aN of the second zero-crossing point, where a is the time interval between the zero-crossing times of two adjacent voltage zero-crossing points.

[0133] Taking the AC frequency of 50Hz as an example, a voltage zero crossing is generated every 10ms, that is, the time interval between the zero crossing times of every two adjacent voltage zero crossings is the same, and the time interval a between the zero crossing times of the two adjacent voltage zero crossings is 10ms. When N=1, the second zero crossing is the first voltage zero crossing generated after the first zero crossing. At this time, the zero crossing time for the tail node to generate the second zero crossing is T1+10ms; if N=3, the second zero crossing is the third zero crossing generated after the first zero crossing, and the time interval between the second zero crossing and the first zero crossing is 30ms. When the second zero crossing is generated, the zero crossing time for the tail node to generate the second zero crossing is T1+30ms. It should be noted that the above-mentioned specific determination method of the second zero crossing is introduced with the case of an AC frequency of 50Hz. It is also applicable to the scenario where the AC frequency is not equal to 50Hz (for example, the AC frequency is 60Hz). The embodiment of the present application does not limit the frequency range of the AC.

[0134] Optionally, if the first information also includes a zero-crossing count value M1 of the first zero-crossing point, then when the second zero-crossing point is the Nth voltage zero-crossing point generated after the first zero-crossing point, if the zero-crossing count value of the first zero-crossing point is M1, then when the second zero-crossing point is generated, the tail node generates a zero-crossing time of the second zero-crossing point as T1+aN and a zero-crossing count value of the second zero-crossing point as M1+N. When subsequent voltage zero-crossing points are generated, based on the zero-crossing count value M1+N of the second zero-crossing point, the count value is increased by 1 each time a voltage zero-crossing point is generated.

[0135] In the embodiment of the present application, the head-end node periodically sends the timestamp of the nearest voltage zero-crossing point to the tail-end node, so that after receiving the timestamp of the nearest voltage zero-crossing point, the tail-end node corrects the zero-crossing time of the locally generated voltage zero-crossing point, thereby enabling different nodes in the PLC network to achieve precise time synchronization between different nodes based on the consistency and periodicity of the voltage zero point generation, thereby ensuring that each node in the PLC network can maintain precise time synchronization and avoid the occurrence of inconsistent data cycles in the synchronous collection.

[0136] The above describes a method for time synchronization between a headend node and its adjacent tailend node in a PLC network, as described in an embodiment of the present application. When the tailend node in the above embodiment is a PCO, if the PCO is also connected to a lower-level tailend node, the PCO also needs to achieve precise time synchronization with the lower-level tailend node. In some applications, the headend node or tailend node may also be connected to a terminal device, requiring precise time synchronization between the headend node or tailend node and the connected terminal device. This is further described in the embodiments of the present application.

[0137] Figure 3 A schematic diagram of another embodiment of the time synchronization method provided in an embodiment of the present application.

[0138] See Figure 3 Another embodiment of the time synchronization method provided in the embodiment of the present application may include:

[0139] 301. A head-end node generates voltage zero-crossing data according to a reference time. The voltage zero-crossing data includes a zero-crossing time of the voltage zero-crossing.

[0140] The embodiments of this application can be found in Figure 2 Step 201 in FIG. 1 is understood for simplicity and will not be described in detail here.

[0141] 302. When the first timing time arrives, the head-end node sends first information to the first tail-end node, where the first information includes a timestamp of a first zero-crossing point. The timestamp of the first zero-crossing point is a zero-crossing point time with the smallest time interval between the voltage zero-crossing point time and the first timing time.

[0142] The embodiments of this application can be found in Figure 2 Step 202 in FIG. 1 is understood for simplicity and will not be described in detail here.

[0143] 303. The first tail node determines a zero-crossing time of a second zero-crossing point according to the timestamp of the first zero-crossing point.

[0144] The embodiments of this application can be found in Figure 2 Step 203 in FIG. 1 is understood for simplicity and will not be described in detail here.

[0145] 304. The first tail node calibrates the local time according to the timestamp of the first zero-crossing point.

[0146] In the embodiment of the present application, after receiving the first information sent by the head-end node, the first tail-end node may further calibrate the local time according to the timestamp of the first zero-crossing point.

[0147] In an embodiment of the present application, the local time of the first tail node refers to the current time recorded locally by the device of the first tail node. The local time may deviate from the reference time. Therefore, the first tail node can also calibrate the local time based on the timestamp of the first zero crossing point.

[0148] Specifically, the way in which the first tail end node calibrates the local time according to the timestamp of the first zero-crossing point can be: after the first tail end node receives the first information sent by the casting node and extracts the timestamp of the first zero-crossing point, it immediately updates the local time according to the timestamp of the first zero-crossing point, thereby realizing the calibration of the local time.

[0149] It should be noted that step 304 in the embodiment of the present application is an optional step.

[0150] 305. When the second timing time arrives, the head-end node sends a second message to the first terminal device. The second message includes a timestamp of a third zero-crossing point. The timestamp of the third zero-crossing point is a zero-crossing point time of the voltage zero-crossing point generated by the head-end node with the shortest time interval with the second timing time.

[0151] In the embodiment of the present application, the second timing time may be the same as the first timing time, or may be different from the first timing time. That is: after the head end node generates the data of the voltage zero crossing according to the reference time, it may be to send corresponding information to the first tail end node and the first terminal device respectively at the same time, or it may be to send corresponding information to the first tail end node and the first terminal device successively, and the cycle of the first timing time may be longer than the cycle of the second timing time, or it may be shorter than the cycle of the second timing time, and the embodiment of the present application does not limit this. For example, the first timing time is set to 200 zero crossing voltages, that is, the cycle of the first timing time is 2S, and the second timing time is set to 100 zero crossing voltages, that is, the cycle of the second timing time is 1S.

[0152] In an embodiment of the present application, after the head-end node generates data on the voltage zero crossing based on the reference time, when the second timing time arrives, the head-end node sends a second message to the first terminal device connected to it, and the second message includes a timestamp of the third zero crossing. The timestamp of the third zero crossing is the zero crossing time of the voltage zero crossing with the smallest time interval with the second timing time, that is, the third zero crossing is the voltage zero crossing closest to the arrival time of the second timing time. When the second timing time arrives, the head-end node sends the zero crossing timestamp of the most recently generated voltage zero crossing to the first terminal device.

[0153] It should be noted that in the embodiments of the present application, the first terminal device may refer to any one of one or more terminal devices connected to the head-end node. The first terminal device and the head-end node may be connected via a universal asynchronous receiver / transmitter (UART) serial port. The head-end node may send the second information to the first terminal device via the UART serial port.

[0154] 306. The first terminal device determines a zero-crossing time of a fourth zero-crossing point based on the timestamp of the third zero-crossing point.

[0155] In an embodiment of the present application, after receiving the second information sent by the head-end node, the first terminal device determines the zero-crossing time of the fourth zero-crossing point based on the timestamp of the third zero-crossing point contained in the second information.

[0156] Optionally, the head-end node and the first terminal device can use the same crystal oscillator, for example, share a voltage zero-crossing detection circuit, or they can use different crystal oscillators. When the head-end node and the first terminal device respectively use different crystal oscillators, the second information sent by the head-end node to the first terminal device can also include the zero-crossing count value of the third zero-crossing point.

[0157] In the embodiment of the present application, the first terminal device also continuously generates the zero-crossing time of the voltage zero-crossing point under the drive of the voltage zero-crossing detection circuit. The fourth zero-crossing point can be the same voltage zero-crossing point as the third zero-crossing point, or it can be a voltage zero-crossing point different from the third zero-crossing point. For example, the fourth zero-crossing point is the Nth voltage zero-crossing point generated after the third zero-crossing point. The specific method for the first terminal device to determine the zero-crossing time of the fourth zero-crossing point based on the timestamp of the third zero-crossing point can be:

[0158] If the fourth zero-crossing point is the same voltage zero-crossing point as the third zero-crossing point, the first terminal device will immediately modify the zero-crossing time t3 of the third zero-crossing point generated by this end to the zero-crossing time T3 of the third zero-crossing point contained in the received second information after receiving the second information. When a subsequent voltage zero-crossing point occurs, the zero-crossing time of each voltage zero-crossing point is generated based on the updated zero-crossing time T3 of the third zero-crossing point.

[0159] Optionally, if the second information also includes the zero-crossing count value M3 of the third zero-crossing point, when the fourth zero-crossing point is the same voltage zero-crossing point as the third zero-crossing point, the first terminal device will not only modify the zero-crossing time t3 of the third zero-crossing point generated by this end to the zero-crossing time T3 of the third zero-crossing point contained in the received second information, but will also modify the zero-crossing count value m3 of the third zero-crossing point generated by this end to the zero-crossing count value M3 of the third zero-crossing point contained in the received second information. When a subsequent voltage zero-crossing point occurs, based on the updated zero-crossing count value M3 of the third zero-crossing point, the count value is +1 each time a voltage zero-crossing point is generated.

[0160] If the fourth zero-crossing point is a voltage zero-crossing point different from the third zero-crossing point, for example, the fourth zero-crossing point is the Nth voltage zero-crossing point after the third zero-crossing point, after receiving the second information, when the fourth zero-crossing point occurs, if the timestamp of the third zero-crossing point is T3, the zero-crossing time of the fourth zero-crossing point is generated as T3+aN. When subsequent voltage zero-crossing points occur, the zero-crossing time of each voltage zero-crossing point is generated based on the zero-crossing time T3+aN of the fourth zero-crossing point, where a is the time interval between the zero-crossing times of two adjacent voltage zero-crossing points.

[0161] Optionally, if the second information further includes a zero-crossing count value M3 of the third zero-crossing point, then when the fourth zero-crossing point is the Nth voltage zero-crossing point generated after the third zero-crossing point, the first terminal device generates a zero-crossing count value M3+N for the fourth zero-crossing point in addition to generating a time T3+aN for the fourth zero-crossing point. Upon subsequent voltage zero-crossing points, based on the zero-crossing count value M3 of the fourth zero-crossing point, the count value is incremented by 1 each time a voltage zero-crossing point is generated.

[0162] It should be noted that this can also be seen Figure 2 In step 203, the tail end node understands a method for determining the timestamp and the zero-crossing count value of the second zero-crossing point based on the timestamp and the zero-crossing count value of the first zero-crossing point.

[0163] 307. When the third timing time arrives, the first tail end node sends the third information to the second tail end node. The third information includes the timestamp of the fifth zero crossing point. The timestamp of the fifth zero crossing point is the zero crossing time of the voltage zero crossing point generated by the first tail end node based on the zero crossing time of the second zero crossing point, and the time interval between the zero crossing time and the third timing time is the smallest.

[0164] In an embodiment of the present application, after determining the zero-crossing time of the second zero-crossing point based on the timestamp of the first zero-crossing point, the first tail node generates subsequent voltage zero-crossing data based on the zero-crossing time of the second zero-crossing point. The voltage zero-crossing data includes the zero-crossing time of the voltage zero-crossing point. Optionally, the voltage zero-crossing data may also include a zero-crossing count value of the voltage zero-crossing point.

[0165] It should be noted that the first tail end node in the embodiment of the present application is PCO, and the first tail end node is also connected to the second tail end node. Therefore, the first tail end node also needs to send the third information to the second tail end node so that the second tail end node completes time precision synchronization. The third information includes the timestamp of the fifth zero crossing, and the timestamp of the fifth zero crossing is the zero crossing time with the smallest time interval between the zero crossing time of the voltage zero crossing and the third timing time. That is, the fifth zero crossing is the voltage zero crossing closest to the arrival time of the third timing time, and when the third timing time arrives, the zero crossing timestamp of the most recently generated voltage zero crossing is sent to the second tail end node. The third information can be a proxy beacon, that is, the first tail end node sends the timestamp of the fifth zero crossing to the second tail end node by means of a proxy beacon.

[0166] In the embodiment of the present application, the third timer can be determined based on the scale of the PLC network. The third timer can be a multiple of 1ms. In the embodiment of the present application, the third timer can be the same as at least one of the first timer and the second timer, or can be different from either the first timer or the second timer, and this embodiment of the present application is not limited thereto.

[0167] 308. The second tail node determines a zero-crossing time of a sixth zero-crossing point according to the timestamp of the fifth zero-crossing point.

[0168] In the embodiment of the present application, after receiving the third information sent by the first tail end node, the second tail end node determines the zero-crossing time of the sixth zero-crossing point based on the timestamp of the fifth zero-crossing point therein.

[0169] Optionally, in an embodiment of the present application, when the quality of the crystal oscillators used in the first tail end node and the second tail end node is not high and there may be false detection of the zero crossing count value, the third information sent by the first tail end node to the second tail end node may also include the zero crossing count value of the fifth zero crossing.

[0170] In the embodiment of the present application, the second end node determines the timestamp and zero-crossing count value of the sixth zero-crossing point based on the timestamp and zero-crossing count value of the fifth zero-crossing point in principle. Figure 2 The same method is used in step 203 where the tail node determines the zero-crossing time of the second zero-crossing point based on the timestamp of the first zero-crossing point. Figure 2 Step 203 in FIG. 1 is understood for simplicity and will not be described in detail here.

[0171] 309. The second tail node calibrates the local time according to the timestamp of the fifth zero-crossing point.

[0172] The embodiment of the present application can be understood by referring to the calibration of the local time by the first tail node according to the timestamp of the first zero-crossing point in step 304, which will not be repeated here.

[0173] It should be noted that step 309 in the embodiment of the present application is an optional step.

[0174] 310. When the fourth timing time arrives, the first tail end node sends fourth information to the second terminal device. The fourth information includes the timestamp of the seventh zero crossing point. The timestamp of the seventh zero crossing point is the zero crossing time of the voltage zero crossing point generated by the first tail end node based on the zero crossing time of the second zero crossing point, and the time interval between the zero crossing time and the fourth timing time is the smallest.

[0175] In the embodiment of the present application, the second terminal device may refer to any one of one or more terminal devices connected to the first tail node. The second terminal device and the first tail node may be connected via a UART serial port. The first tail node may send the fourth information to the second terminal device via the UART serial port.

[0176] In the embodiment of the present application, the fourth timing time may be the same as at least one of the first timing time, the second timing time and the third timing time, or may be different from the first timing time, the second timing time and the third timing time. This embodiment of the present application does not limit this.

[0177] In the embodiment of the present application, the time synchronization method between the first tail node and the second terminal device can be understood by referring to the time synchronization method between the head node and the first terminal device in step 305, which will not be repeated here.

[0178] 311. The second terminal device determines the zero-crossing time of the eighth zero-crossing point based on the timestamp of the seventh zero-crossing point.

[0179] In the embodiment of the present application, after receiving the fourth information sent by the first tail node, the second terminal device determines the zero-crossing time of the eighth zero-crossing point based on the timestamp of the seventh zero-crossing point included in the fourth information.

[0180] Optionally, the first tail end node and the second terminal device can use the same crystal oscillator, for example, share a voltage zero-crossing detection circuit, or they can use different crystal oscillators. When the first tail end node and the second terminal device respectively use different crystal oscillators, the fourth information sent by the first tail end node to the second terminal device can also include the zero-crossing count value of the seventh zero-crossing point.

[0181] In the embodiment of the present application, the manner in which the second terminal device determines the timestamp and zero-crossing count value of the eighth zero-crossing point based on the timestamp and zero-crossing count value of the seventh zero-crossing point is the same in principle as the manner in which the first terminal device determines the zero-crossing time and zero-crossing count value of the fourth zero-crossing point based on the timestamp and zero-crossing count value of the third zero-crossing point in step 306. Please refer to step 306 for understanding and will not be repeated here.

[0182] It should be noted that in the embodiments of the present application, the second tail node can be either a PCO or an STA. If the second tail node is a PCO, it can also be connected to a third tail node, and so on. Time synchronization between the tail nodes can be achieved using the same method as described in the aforementioned steps. When the second tail node is also connected to a corresponding third terminal device, the time synchronization method between them is the same as the synchronization method between the first tail node and the second terminal device.

[0183] It should be noted that the present embodiment does not limit the order between step 302-step 303 and step 305-step 306. The present embodiment does not limit the order between step 307-step 308 and step 310-step 311.

[0184] It should be noted that the first tail node in the embodiment of the present application can be a PCO or a STA. If the type of the first tail node is STA, the first tail node will not connect to the tail node of the next level, and steps 307 and 308 do not exist.

[0185] It should be noted that if the head-end node or the tail-end node is not connected to the terminal device, the time synchronization solution between the head-end node or the tail-end node and the terminal device is an optional solution.

[0186] In the embodiment of the present application, the head-end node generates data on the voltage zero-crossing point based on the reference time, and then sends the timestamp of the nearest voltage zero-crossing point to the tail-end node and the connected terminal device at regular intervals, so that the devices connected to the head-end node can correct the zero-crossing time of the locally generated voltage zero-crossing point after receiving the timestamp of the nearest voltage zero-crossing point, so that different nodes and terminal devices in the PLC network can achieve precise time synchronization between different nodes based on the consistency and periodicity of the voltage zero point generation, ensuring that each node in the PLC network can maintain precise time synchronization and avoid the occurrence of inconsistent data cycles in the synchronously collected data.

[0187] The above describes the time synchronization method provided in the embodiment of the present application. Next, the network devices in the PLC network in the embodiment of the present application will be introduced. First, refer to Figure 4 .

[0188] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of interaction between each node. It is understandable that, in order to realize the above functions, the head-end node, tail-end node or terminal device includes a hardware structure and / or software module corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the modules and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0189] From the perspective of hardware structure, the head-end node or the tail-end node can be implemented by one physical device, or by multiple physical devices, or by a logical function module within a physical device. The embodiments of the present application do not make specific limitations on this.

[0190] For example, the above Figures 1 to 3 Any of the head end node or tail end node in Figure 4 The network device 400 is implemented in the PLC network. The network device 400 is applied to a PLC network, and the PLC network includes a head-end node and at least one tail-end node connected to the head-end node. The network device 400 can be the above-mentioned Figure 1-Figure 3 The head end node, or the network device 400 may also be the above Figure 1-Figure 3 The network device 400 includes a processor 410, a memory 420 and a transceiver 430. The transceiver 430 is used to communicate with other devices or communication networks.

[0191] The processor 410 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (server IC), or one or more integrated circuits for controlling the execution of the program of the present application.

[0192] The memory 420 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 420 may exist independently and be connected to the processor 410. The memory 420 may also be integrated with the processor 410.

[0193] The memory 420 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 410. The processor 410 is used to execute the computer-executable instructions stored in the memory 420, thereby implementing the time synchronization method provided by the embodiment of the present application.

[0194] Specifically, when the network device 400 is Figure 1-Figure 3 When the headend node is in the process of FIG. 1 , the processor 410 is configured to:

[0195] Generate voltage zero-crossing data based on the reference time, the voltage zero-crossing data including the voltage zero-crossing time; when the first timing time arrives, send first information to the tail node, the first information including the timestamp of the first zero-crossing, the timestamp of the first zero-crossing being the zero-crossing time with the smallest time interval between the voltage zero-crossing time and the first timing time, the timestamp of the first zero-crossing being used by the tail node to determine the zero-crossing time of the second zero-crossing. For specific implementation, see Figure 2 In the embodiment shown, steps 201 to 203, and Figure 3The detailed description of steps 301 to 303 in the illustrated embodiment will not be repeated here.

[0196] Specifically, when the network device 400 is Figure 1-Figure 3 When the tail node in the process is a node, the processor 410 is configured to:

[0197] Receive first information sent by the head-end node when a first timing time arrives, the first information including a timestamp of a first zero-crossing point, the timestamp of the first zero-crossing point being the zero-crossing point time of the voltage zero-crossing point generated by the head-end node based on the reference time, with the shortest interval between the first timing time; determine the zero-crossing point time of a second zero-crossing point based on the timestamp of the first zero-crossing point. For specific implementation, see Figure 2 In the embodiment shown, steps 201 to 203, and Figure 3 The detailed description of steps 301 to 303 in the illustrated embodiment will not be repeated here.

[0198] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0199] The embodiments of the present application can divide the functional modules of the network device according to the above method examples. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiments of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods.

[0200] For example, when the functional modules are divided in an integrated manner, Figure 5 A schematic diagram of the structure of a network device is shown. The network device 500 corresponds to Figure 1-Figure 3 The headend node in an embodiment.

[0201] See Figure 5 The network device 500 provided in the embodiment of the present application is applied to a PLC network. The network device is the above-mentioned Figure 1-Figure 3 The PLC network further comprises at least one tail-end node connected to the network device, and the network device 500 may include:

[0202] Generating unit 501 is used to generate voltage zero-crossing data according to the reference time, wherein the voltage zero-crossing data includes the voltage zero-crossing time. Figure 2 A detailed description of step 201 in the illustrated embodiment, and Figure 3The detailed description of step 301 in the illustrated embodiment will not be repeated here.

[0203] The sending unit 502 is configured to send first information to the tail node when the first timing time arrives. The first information includes a timestamp of a first zero-crossing point. The timestamp of the first zero-crossing point is the zero-crossing point time with the smallest time interval between the zero-crossing points of the voltage generated by the generating unit 501 and the first timing time. The timestamp of the first zero-crossing point is used by the tail node to determine the zero-crossing point time of the second zero-crossing point. For specific implementation methods, please refer to Figure 2 A detailed description of steps 202-203 in the illustrated embodiment, and Figure 3 The detailed description of steps 302 and 303 in the illustrated embodiment will not be repeated here.

[0204] The network device of the embodiment of the present application periodically sends the timestamp of the nearest voltage zero-crossing point to the tail-end node, so that after receiving the timestamp of the nearest voltage zero-crossing point, the tail-end node corrects the zero-crossing time of the locally generated voltage zero-crossing point, thereby enabling different nodes in the PLC network to achieve precise time synchronization between different nodes based on the consistency and periodicity of the voltage zero point generation, thereby ensuring that each node in the PLC network can maintain precise time synchronization and avoid the occurrence of inconsistent data cycles in the synchronously collected data.

[0205] Optionally, as an embodiment, when the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point. Figure 2 A detailed description of step 203 in the illustrated embodiment, and Figure 3 The detailed description of step 303 in the illustrated embodiment will not be repeated here.

[0206] Optionally, as an embodiment, the voltage zero-crossing data further includes a zero-crossing count value of the voltage zero-crossing, and the first information further includes a zero-crossing count value of the first zero-crossing. The zero-crossing count value of the first zero-crossing is used by the tail node to determine the zero-crossing count value of the second zero-crossing. For specific implementation methods, please refer to Figure 2 A detailed description of step 203 in the illustrated embodiment, and Figure 3 The detailed description of step 303 in the illustrated embodiment will not be repeated here.

[0207] Optionally, as an embodiment, when the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point. Figure 2 A detailed description of step 203 in the illustrated embodiment, and Figure 3 The detailed description of step 303 in the illustrated embodiment will not be repeated here.

[0208] Optionally, as an embodiment, the timestamp of the first zero-crossing point is also used by the tail node to calibrate the local time. Figure 3 The detailed description of step 304 in the illustrated embodiment will not be repeated here.

[0209] Optionally, as an embodiment, the network device 500 is connected to a terminal device, and the sending unit is further configured to send second information to the terminal device when a second timing time arrives after the generating unit 501 generates the voltage zero-crossing data according to the reference time, wherein the second information includes a timestamp of a third zero-crossing point, and the timestamp of the third zero-crossing point is the zero-crossing point time with the smallest time interval with the second timing time among the zero-crossing points of the voltage. The timestamp of the third zero-crossing point is used by the terminal device to determine the zero-crossing point time of the fourth zero-crossing point. For specific implementation methods, please refer to Figure 3 The detailed description of steps 305 and 306 in the illustrated embodiment will not be repeated here.

[0210] Optionally, as an embodiment, the voltage zero-crossing data further includes a zero-crossing count value of the voltage zero-crossing, and the second information further includes a zero-crossing count value of the third zero-crossing, and the zero-crossing count value of the third zero-crossing is used by the terminal device to determine the zero-crossing count value of the fourth zero-crossing. For specific implementation methods, please refer to Figure 3 The detailed description of step 306 in the illustrated embodiment will not be repeated here.

[0211] Optionally, as an embodiment, the timestamp of the third zero-crossing point is also used by the terminal device to calibrate the local time.

[0212] Optionally, as an embodiment, the network device 500 further includes: an acquisition unit 503, configured to acquire the reference time before the generation unit 501 generates the voltage zero-crossing point data according to the reference time. Figure 2 For a detailed description of step 201 in the embodiment shown, please refer to Figure 3 The detailed description of step 301 in the illustrated embodiment will not be repeated here.

[0213] It should be understood that the generating unit 501 and the acquiring unit 503 in the above embodiment may be implemented by a processor or processor-related circuit components, and the sending unit 502 in the above embodiment may be implemented by a transceiver or transceiver-related circuit components.

[0214] In addition, the generating unit 501, the sending unit 502 and the acquiring unit 503 may be software functional units, that is, the kinetic energy steps of these units described above are implemented by software. In this case, these software units may be stored in Figure 4 In the embodiment shown, the software code in the memory 420 is executed when the processor 410 reads the software code in the memory 420. Figure 4 The functions of the processor in the embodiment shown are shown in FIG. Figure 4 The detailed description of the processor 410 in FIG. 4 is omitted here.

[0215] Figure 6 A schematic diagram of the structure of another network device 600 provided in an embodiment of the present application is shown. The network device 600 corresponds to Figure 1-Figure 3 The tail end node, the first tail end node or the second tail end node in the embodiment.

[0216] See Figure 6 The network device 600 provided in an embodiment of the present application is applied to a PLC network. The PLC network also includes a headend node connected to the network device 600. The network device 600 may include:

[0217] The receiving unit 601 is configured to receive the first information sent by the head-end node when the first timing time arrives. The first information includes a timestamp of a first zero-crossing point. The timestamp of the first zero-crossing point is the zero-crossing point time of the voltage zero-crossing point generated by the head-end node based on the reference time, and the zero-crossing point time with the shortest interval with the first timing time. For specific implementation methods, please refer to Figure 2 The description of steps 201 and 202 in the illustrated embodiment, and Figure 3 The detailed description of steps 301 and 302 in the illustrated embodiment will not be repeated here.

[0218] The determining unit 602 is configured to determine the zero-crossing time of the second zero-crossing point according to the timestamp of the first zero-crossing point in the first information received by the receiving unit 601. For specific implementation methods, please refer to Figure 3 A detailed description of step 203 in the illustrated embodiment, and Figure 3 The detailed description of step 303 in the illustrated embodiment will not be repeated here.

[0219] Optionally, as an embodiment, when the first zero-crossing point and the second zero-crossing point are the same, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point. Figure 2 A detailed description of step 203 in the illustrated embodiment, and Figure 3 The detailed description of step 303 in the illustrated embodiment will not be repeated here.

[0220] Optionally, as an embodiment, the first information further includes the zero-crossing count value of the first zero-crossing point, and the determining unit 602 is further configured to determine the zero-crossing count value of the second zero-crossing point based on the zero-crossing count value of the first zero-crossing point after the receiving unit 601 receives the first information sent by the head-end node when the first timing time arrives. For specific implementation methods, please refer to Figure 2 A detailed description of step 203 in the illustrated embodiment, and Figure 3 The detailed description of step 303 in the illustrated embodiment will not be repeated here.

[0221] Optionally, as an embodiment, when the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point. Figure 2 A detailed description of step 203 in the illustrated embodiment, and Figure 3 The detailed description of step 303 in the illustrated embodiment will not be repeated here.

[0222] Optionally, as an embodiment, the network device 600 further includes: a calibration unit 603, configured to calibrate the local time according to the timestamp of the first zero-crossing point after the receiving unit 601 receives the first information sent by the head-end node when the first timing time arrives. For specific implementation methods, please refer to Figure 3 The detailed description of step 304 in the illustrated embodiment will not be repeated here.

[0223] Optionally, as an embodiment, the first tail node is connected to a terminal device, and the network device 600 further includes: a generating unit 604, configured to generate voltage zero-crossing data according to the zero-crossing time of the second zero-crossing point after the determining unit 602 determines the zero-crossing time of the second zero-crossing point according to the timestamp of the first zero-crossing point, wherein the voltage zero-crossing data includes the zero-crossing time of the voltage zero-crossing point; a sending unit 605, configured to send second information to the terminal device when the second timing time arrives, wherein the second information includes the timestamp of the third zero-crossing point, wherein the timestamp of the third zero-crossing point is the zero-crossing time of the voltage zero-crossing point generated by the generating unit 604 with the smallest time interval with the second timing time, and the timestamp of the third zero-crossing point is used by the terminal device to determine the zero-crossing time of the fourth zero-crossing point. For specific implementation methods, please refer to Figure 3 The detailed description of steps 310 and 311 in the illustrated embodiment will not be repeated here.

[0224] Optionally, as an embodiment, the voltage zero-crossing data further includes a zero-crossing count value of the voltage zero-crossing, and the second information further includes a zero-crossing count value of the third zero-crossing, and the zero-crossing count value of the third zero-crossing is used by the terminal device to determine the zero-crossing count value of the fourth zero-crossing. For specific implementation methods, please refer to Figure 3 The detailed description of step 311 in the illustrated embodiment will not be repeated here.

[0225] Optionally, as an embodiment, the timestamp of the third zero-crossing point is also used by the terminal device to calibrate the local time.

[0226] Optionally, as an embodiment, the sending unit 605 is further configured to send third information to the second tail end node when the third timing time arrives, the third information including a timestamp of a fifth zero crossing point, the timestamp of the fifth zero crossing point being the zero crossing point time of the voltage zero crossing point generated by the generating unit 604, with the smallest time interval with the third timing time, and the timestamp of the fifth zero crossing point is used by the second tail end node to determine the zero crossing point time of the sixth zero crossing point. For specific implementation methods, please refer to Figure 3 The detailed description of steps 307 and 308 in the illustrated embodiment will not be repeated here.

[0227] Optionally, as an embodiment, the third information further includes the zero-crossing count value of the fifth zero-crossing point, and the zero-crossing count value of the fifth zero-crossing point is used by the second tail node to determine the zero-crossing count value of the sixth zero-crossing point. Figure 3 The detailed description of step 308 in the illustrated embodiment will not be repeated here.

[0228] It should be understood that the determination unit 602, calibration unit 603 and generation unit 604 in the above embodiment can be implemented by a processor or processor-related circuit components, and the receiving unit 601 and sending unit 605 in the above embodiment can be implemented by a transceiver or transceiver-related circuit components.

[0229] In addition, the receiving unit 601, the determining unit 602, the calibration unit 603, the generating unit 604 and the sending unit 605 may be software functional units, that is, the kinetic energy steps of these units described above are implemented by software. In this case, these software units may be stored in Figure 4 In the embodiment shown, the software code in the memory 420 is executed when the processor 410 reads the software code in the memory 420. Figure 4 The functions of the processor in the embodiment shown are shown in FIG. Figure 4 The detailed description of the processor 410 in FIG. 4 is omitted here.

[0230] The present application also provides a PLC device, such as Figure 7 The PLC device 70 includes: a transmitter 701a, a receiver 701b, a processor 702, a memory 703 and a bus system 704;

[0231] Memory 703 is used to store programs. Specifically, the programs may include program code, which includes computer operating instructions. Memory 703 may be random access memory (RAM) or non-volatile memory, such as at least one disk storage device. The figure shows only one memory; however, multiple memories may be provided as needed. Memory 703 may also be memory in processor 702.

[0232] The memory 703 stores the following elements, executable modules or data structures, or a subset or an extension thereof:

[0233] Operation instructions: include various operation instructions, used to implement various operations.

[0234] Operating system: includes various system programs used to implement various basic services or process hardware-based tasks.

[0235] The processor 702 controls the operation of the PLC device 70. The processor 702 may be a central processing unit (CPU). In a specific application, the various components of the PLC device 70 are coupled together via a bus system 704. In addition to a data bus, the bus system 704 may also include a power bus, a control bus, and a status signal bus. However, for the sake of clarity, the various buses are labeled as the bus system 704 in the figure. For ease of illustration, Figure 7 The drawing is only schematic.

[0236] The method disclosed in the above-mentioned embodiment of the present application can be applied to the processor 702 or implemented by the processor 702.

[0237] Processor 702 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in processor 702 or by software instructions. The above-mentioned processor 702 may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of this application can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in memory 703. Processor 702 reads the information in memory 703 and, in conjunction with its hardware, executes the method steps performed by the headend node or tailend node above.

[0238] In some implementations, the processor 702 is configured to read the information in the memory 703 to implement the aforementioned aspects related to the headend node and the methods provided in any of its implementations. Specifically, the processor 702 is configured to execute the operations performed by the generating unit 501 and the acquiring unit 503 in the above embodiments.

[0239] Correspondingly, the transmitter 701a and the receiver 701b are used to send and receive data, respectively. Specifically, the transmitter 701a is used to perform the operations performed by the sending unit 502 in the above embodiment.

[0240] In other implementations, the processor 702 may also be configured to read the information in the memory 703 to implement the aforementioned aspects with tail nodes and the methods provided in any of their implementations. Specifically, the processor 702 is configured to execute the operations performed by the determining unit 602, the calibrating unit 603, and the generating unit 604 in the above-described embodiments.

[0241] Correspondingly, the transmitter 701a and the receiver 701b are used to send and receive data, respectively. Specifically, the transmitter 701a is used to perform the operations performed by the sending unit 605 in the above embodiment, and the receiver 701b is used to perform the operations performed by the receiving unit 601 in the above embodiment.

[0242] Optionally, when the voltage zero-crossing point is detected by adding a voltage zero-crossing detection circuit in the head-end node or the tail-end node in the embodiment of the present application, the voltage zero-crossing detection circuit can be located inside the processor 702 or outside the processor 702 in the PLC device. The embodiment of the present application does not specifically limit the location of the voltage zero-crossing detection circuit.

[0243] The PLC device 70 of the embodiment of the present application may correspond to the head-end node or the tail-end node in the time synchronization method of the embodiment of the present application, and the operations and / or functions of each module in the PLC device 70 are respectively to realize Figures 1 to 3 The corresponding processes of each method related to the head end node, or the operations and / or functions of each module in the PLC device 70 are respectively to achieve Figures 1 to 3 For the sake of brevity, the corresponding processes of each method related to the tail node are not repeated here.

[0244] like Figure 8 As shown, the embodiment of the present application further provides a terminal device 80. The terminal device 80 is applied to a PLC network, and the PLC network includes a head-end node and at least one tail-end node connected to the head-end node. The terminal device 80 can be the above Figure 1-Figure 3 The terminal device 80 includes a processor 810, a memory 820, and a transceiver 830. The memory 820 stores instructions or programs, and the processor 810 is used to execute the instructions or programs stored in the memory 820. The transceiver 830 is used to communicate with other devices or communication networks.

[0245] The processor 810 can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (server IC), or one or more integrated circuits used to control the execution of the program of the present application.

[0246] The memory 820 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 820 may exist independently and be connected to the processor 810. The memory 820 may also be integrated with the processor 810.

[0247] The memory 820 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 810. The processor 810 is used to execute the computer-executable instructions stored in the memory 820, thereby implementing the time synchronization method provided by the embodiment of the present application.

[0248] Specifically, the processor 810 is configured to:

[0249] Receive first information sent by a first node when a first timing time arrives, the first information including a first zero-crossing timestamp, the first zero-crossing timestamp being the zero-crossing times of the voltage zero-crossings generated by the first node with the smallest time interval between the first timing time; determine a second zero-crossing timestamp based on the first zero-crossing timestamp. For specific implementation, see Figure 3 The detailed description of steps 305-306, and steps 310-311 in the illustrated embodiment will not be repeated here.

[0250] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0251] The embodiment of the present application can divide the functional modules of the terminal device according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods.

[0252] For example, when the functional modules are divided in an integrated manner, Figure 9 A schematic diagram of the structure of a terminal device is shown. The terminal device 90 corresponds to Figure 1-Figure 3 The terminal device, the first terminal device or the second terminal device in the embodiment.

[0253] See Figure 9 The terminal device 90 provided in the embodiment of the present application may include:

[0254] The receiving unit 901 is configured to receive first information sent by a first node when a first timing time arrives. The first information includes a timestamp of a first zero-crossing point. The timestamp of the first zero-crossing point is the zero-crossing point time of the voltage zero-crossing points generated by the first node with the shortest time interval between the first timing time and the zero-crossing point time. For specific implementation methods, see Figure 3 The detailed description of step 305 or step 310 in the illustrated embodiment will not be repeated here.

[0255] The determining unit 902 is configured to determine the timestamp of the second zero-crossing point according to the timestamp of the first zero-crossing point in the information received by the receiving unit 901. Figure 3 The detailed description of step 306 or step 311 in the illustrated embodiment will not be repeated here.

[0256] Optionally, as an embodiment, when the first node is the head-end node, the zero-crossing time of the voltage zero-crossing point is generated by the first node according to the reference time. Figure 2 A detailed description of step 201 in the illustrated embodiment, and Figure 3 The detailed description of step 301 in the illustrated embodiment will not be repeated here.

[0257] Optionally, as an embodiment, when the first node is the tail node, the zero-crossing time of the voltage zero-crossing point is generated by the first node based on the timestamp of the third zero-crossing point, the timestamp of the third zero-crossing point is sent by the second node to the first node when the second timing time arrives, and the timestamp of the third zero-crossing point is the zero-crossing time with the smallest time interval between the timestamps of the voltage zero-crossing points generated by the second node and the second timing time. For specific implementation methods, please refer to Figure 3 The detailed description of step 310 in the illustrated embodiment will not be repeated here.

[0258] Optionally, as an embodiment, the first information further includes the zero-crossing count value of the first zero-crossing point, and the determining unit 902 is further configured to determine the zero-crossing count value of the second zero-crossing point based on the zero-crossing count value of the first zero-crossing point. Figure 2 A detailed description of step 306 in the illustrated embodiment, and Figure 3 The detailed description of step 311 in the illustrated embodiment will not be repeated here.

[0259] Optionally, as an embodiment, the terminal device 90 further includes: a calibration unit 903, configured to calibrate the local time according to the timestamp of the first zero-crossing point after the receiving unit receives the first information sent by the first node when the first timing time arrives. For specific implementation methods, please refer to Figure 3 The detailed description of step 304 and step 309 in the illustrated embodiment will not be repeated here.

[0260] It should be understood that the determining unit 902 and the calibration unit 903 in the above embodiment may be implemented by a processor or processor-related circuit components, and the receiving unit 901 in the above embodiment may be implemented by a transceiver or transceiver-related circuit components.

[0261] In addition, the determining unit 902, the calibration unit 903 and the receiving unit 901 may be software functional units, that is, the kinetic energy steps of these units described above are implemented by software. In this case, these software units may be stored in Figure 8 In the embodiment shown, the software code in the memory 820 is executed when the processor 810 reads the software code in the memory 820. Figure 8 The functions of the processor in the embodiment shown are shown in FIG. Figure 8 The detailed description of the processor 810 in FIG. 8 is omitted here.

[0262] Optionally, an embodiment of the present application provides a chip system, which includes a processor for supporting the head-end node to implement the above-mentioned time synchronization method. In one possible design, the chip system also includes a memory. The memory is used to store the necessary program instructions and data for the head-end node. The chip system can be composed of a chip, or it can include a chip and other discrete devices, such as a PHY for modulation and encoding, a digital-to-analog conversion module, etc., which is not specifically limited in the embodiment of the present application. It should be noted that the memory can be located outside the chip system, and the chip system processor interacts with the storage device outside the chip to execute the synchronization method of the head-end node. For the specific implementation process, please refer to Figure 2 A detailed description of steps 201-202 in the illustrated embodiment, and Figure 3 The detailed description of step 301, step 302 and step 305 in the illustrated embodiment will not be repeated here.

[0263] Optionally, an embodiment of the present application provides a chip system, which includes a processor for supporting the tail node to implement the above-mentioned time synchronization method. In one possible design, the chip system also includes a memory. The memory is used to store the necessary program instructions and data for the tail node. The chip system can be composed of a chip, or it can include a chip and other discrete devices, such as a PHY for modulation and encoding, a digital-to-analog conversion module, etc., which is not specifically limited in the embodiment of the present application. It should be noted that the memory can be located outside the chip system, and the chip system processor interacts with the storage device outside the chip to execute the synchronization method of the tail node. For the specific implementation process, please refer to Figure 2 A detailed description of step 203 in the illustrated embodiment, and Figure 3 The detailed descriptions of step 303, step 304, step 307 and step 310 in the illustrated embodiment are not repeated here.

[0264] Optionally, an embodiment of the present application provides a chip system, which includes a processor for supporting a terminal device to implement the above-mentioned time synchronization method. In one possible design, the chip system also includes a memory. The memory is used to store necessary program instructions and data for the terminal device. The chip system can be composed of a chip, or it can include a chip and other discrete devices, such as a PHY for modulation and encoding, a digital-to-analog conversion module, etc., which is not specifically limited in this embodiment of the present application. It should be noted that the memory can be located outside the chip system, and the chip system processor interacts with the storage device outside the chip to execute the synchronization method of the tail node. For the specific implementation process, please refer to Figure 3 The detailed description of steps 306 and 311 in the illustrated embodiment will not be repeated here.

[0265] The present application also provides a PLC communication system, which includes the aforementioned head-end node and one or more tail-end nodes connected to the head-end node. Optionally, the PLC communication system may also include one or more of the aforementioned terminal devices. The head-end node, tail-end node, and terminal device in this embodiment may be the aforementioned Figure 1-9 The headend node, tailend node, and terminal device described in.

[0266] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0267] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, a computer, a server, or a data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode to another website, a computer, a server, or a data center. The computer-readable storage medium can be any available medium that a computer can store or a data storage device such as a server or a data center that includes one or more available media integrations. The available medium can be a magnetic medium, (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid-state drive Solid State Disk (SSD)), etc.

[0268] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) is integrated into the processor.

[0269] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0270] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0271] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0272] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0273] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0274] The above is a detailed introduction to the time synchronization method, device and storage medium provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A time synchronization method, characterized in that: The method is applied to a PLC network, the PLC network including a head-end node and at least one tail-end node connected to the head-end node, and the method includes: The head-end node generates voltage zero-crossing data according to the reference time, wherein the voltage zero-crossing data includes the zero-crossing time of the voltage zero-crossing; When the first timing time arrives, the head-end node sends the first information to the tail-end node, where the first information includes the timestamp of the first zero-crossing point. The timestamp of the first zero-crossing point is the zero-crossing time with the smallest time interval between the zero-crossing time of the voltage zero-crossing point and the first timing time. The timestamp of the first zero-crossing point is used by the tail-end node to determine the zero-crossing time of the second zero-crossing point.

2. The method according to claim 1, characterized in that When the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point.

3. The method according to claim 1 or 2, characterized in that The voltage zero-crossing data also includes a zero-crossing count value of the voltage zero-crossing, and the first information also includes a zero-crossing count value of the first zero-crossing. The zero-crossing count value of the first zero-crossing is used by the tail node to determine the zero-crossing count value of the second zero-crossing.

4. The method according to claim 3, characterized in that When the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point.

5. The method according to any one of claims 1-2, characterized in that: The timestamp of the first zero-crossing point is also used by the tail-end node to calibrate the local time.

6. The method according to any one of claims 1-2, characterized in that: The head-end node is connected to the terminal device, and after the head-end node generates voltage zero-crossing data according to the reference time, the method further includes: When the second timing time arrives, the head-end node sends second information to the terminal device, and the second information includes the timestamp of the third zero-crossing point. The timestamp of the third zero-crossing point is the zero-crossing time of the voltage zero-crossing point with the smallest time interval with the second timing time. The timestamp of the third zero-crossing point is used by the terminal device to determine the zero-crossing time of the fourth zero-crossing point.

7. The method according to claim 6, characterized in that The voltage zero-crossing data also includes the zero-crossing count value of the voltage zero-crossing, and the second information also includes the zero-crossing count value of the third zero-crossing. The zero-crossing count value of the third zero-crossing is used by the terminal device to determine the zero-crossing count value of the fourth zero-crossing.

8. The method according to claim 6, characterized in that The timestamp of the third zero-crossing point is also used by the terminal device to calibrate the local time.

9. The method according to any one of claims 1-2, characterized in that: Before the head-end node generates data of the voltage zero-crossing point according to the reference time, the method further includes: The head-end node obtains the reference time.

10. A time synchronization method, characterized in that: The method is applied to a PLC network, the PLC network including a head-end node and at least one tail-end node connected to the head-end node, and the method includes: The first tail-end node receives first information sent by the head-end node when a first timing time arrives, the first information including a timestamp of a first zero-crossing point, the timestamp of the first zero-crossing point being a zero-crossing point time of voltage zero-crossing points generated by the head-end node based on a reference time, the zero-crossing point time having the shortest interval with the first timing time; The first tail end node determines the zero-crossing time of the second zero-crossing point according to the timestamp of the first zero-crossing point.

11. The method according to claim 10, characterized in that When the first zero-crossing point and the second zero-crossing point are the same, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point.

12. The method according to claim 10 or 11, characterized in that The first information also includes a zero-crossing count value of the first zero-crossing point. After the first tail-end node receives the first information sent by the head-end node when the first timing time arrives, the following further includes: The first tail end node determines the zero-crossing count value of the second zero-crossing point according to the zero-crossing count value of the first zero-crossing point.

13. The method according to claim 12, characterized in that When the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point.

14. The method according to any one of claims 10-11, characterized in that: After the first tail-end node receives the first information sent by the head-end node when the first timing time arrives, the method further includes: The tail end node calibrates the local time according to the timestamp of the first zero-crossing point.

15. The method according to any one of claims 10-11, characterized in that: The first tail end node is connected to the terminal device, and after the first tail end node determines the zero crossing time of the second zero crossing point based on the timestamp of the first zero crossing point, the method further includes: The first tail node generates voltage zero-crossing data according to the zero-crossing time of the second zero-crossing point, wherein the voltage zero-crossing data includes the zero-crossing time of the voltage zero-crossing point; When the second timing time arrives, the first tail end node sends second information to the terminal device, and the second information includes a timestamp of a third zero-crossing point. The timestamp of the third zero-crossing point is the zero-crossing time of the voltage zero-crossing point generated by the first tail end node based on the zero-crossing time of the second zero-crossing point, and the zero-crossing time with the smallest time interval with the second timing time. The timestamp of the third zero-crossing point is used by the terminal device to determine the zero-crossing time of the fourth zero-crossing point.

16. The method according to claim 15, characterized in that The voltage zero-crossing data also includes the zero-crossing count value of the voltage zero-crossing, and the second information also includes the zero-crossing count value of the third zero-crossing. The zero-crossing count value of the third zero-crossing is used by the terminal device to determine the zero-crossing count value of the fourth zero-crossing.

17. The method according to claim 15, characterized in that The timestamp of the third zero-crossing point is also used by the terminal device to calibrate the local time.

18. The method according to claim 15, characterized in that After the first tail node generates voltage zero-crossing point data according to the zero-crossing point time of the second zero-crossing point, the method further includes: When the third timing time arrives, the first tail end node sends third information to the second tail end node, and the third information includes the timestamp of the fifth zero crossing point. The timestamp of the fifth zero crossing point is the zero crossing time of the voltage zero crossing point generated by the first tail end node based on the zero crossing time of the second zero crossing point, and the zero crossing time with the smallest time interval with the third timing time. The timestamp of the fifth zero crossing point is used by the second tail end node to determine the zero crossing time of the sixth zero crossing point.

19. The method according to claim 18, characterized in that The voltage zero-crossing data also includes a zero-crossing count value of the voltage zero-crossing, and the third information also includes a zero-crossing count value of the fifth zero-crossing. The zero-crossing count value of the fifth zero-crossing is used by the second tail node to determine the zero-crossing count value of the sixth zero-crossing.

20. A time synchronization method, characterized in that: The method is applied to a PLC network, the PLC network including a head-end node and at least one tail-end node connected to the head-end node, at least one of the head-end node and the at least one tail-end node being connected to at least one terminal device, the method comprising: The terminal device receives first information sent by the first node when a first timing time arrives, the first information including a timestamp of a first zero-crossing point, where the timestamp of the first zero-crossing point is a zero-crossing point time of a voltage zero-crossing point generated by the first node with the shortest time interval between the first timing time and the zero-crossing point time; The terminal device determines the timestamp of the second zero-crossing point based on the timestamp of the first zero-crossing point.

21. The method according to claim 20, characterized in that When the first node is the head-end node, the zero-crossing time of the voltage zero-crossing point is generated by the first node according to a reference time.

22. The method according to claim 20, characterized in that When the first node is the tail node, the zero-crossing time of the voltage zero-crossing point is generated by the first node based on the timestamp of the third zero-crossing point, the timestamp of the third zero-crossing point is sent by the second node to the first node when the second timing time arrives, and the timestamp of the third zero-crossing point is the zero-crossing time with the smallest time interval between the timestamp of the voltage zero-crossing point generated by the second node and the second timing time.

23. The method according to any one of claims 20 to 22, characterized in that: The first information further includes a zero-crossing count value of the first zero-crossing point, and the method further includes: The terminal device determines the zero-crossing count value of the second zero-crossing point according to the zero-crossing count value of the first zero-crossing point.

24. The method according to any one of claims 20 to 22, characterized in that: After the terminal device receives the first information sent by the first node when the first timing time arrives, the method further includes: The terminal device calibrates the local time according to the timestamp of the first zero-crossing point.

25. A network device, characterized in that: The network device is applied to a PLC network, the network device is a head-end node, the PLC network further includes at least one tail-end node connected to the head-end node, and the network device includes: A generating unit, configured to generate voltage zero-crossing data according to a reference time, wherein the voltage zero-crossing data includes a zero-crossing time of the voltage zero-crossing; A sending unit is used to send first information to the tail node when a first timing time arrives, wherein the first information includes a timestamp of a first zero-crossing point, and the timestamp of the first zero-crossing point is the zero-crossing time of the voltage zero-crossing point generated by the generating unit with the smallest time interval with the first timing time, and the timestamp of the first zero-crossing point is used by the tail node to determine the zero-crossing time of the second zero-crossing point.

26. The network device according to claim 25, characterized in that When the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point.

27. The network device according to claim 25 or 26, characterized in that: The voltage zero-crossing data also includes a zero-crossing count value of the voltage zero-crossing, and the first information also includes a zero-crossing count value of the first zero-crossing. The zero-crossing count value of the first zero-crossing is used by the tail node to determine the zero-crossing count value of the second zero-crossing.

28. The network device according to claim 27, wherein: When the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point.

29. The network device according to any one of claims 25-26, characterized in that: The timestamp of the first zero-crossing point is also used by the tail-end node to calibrate the local time.

30. The network device according to any one of claims 25-26, characterized in that: The network device is connected to the terminal device, The sending unit is also used to send second information to the terminal device when the second timing time arrives after the generating unit generates the data of the voltage zero crossing point according to the reference time. The second information includes the timestamp of the third zero crossing point. The timestamp of the third zero crossing point is the zero crossing time with the smallest time interval between the zero crossing time of the voltage zero crossing point and the second timing time. The timestamp of the third zero crossing point is used by the terminal device to determine the zero crossing time of the fourth zero crossing point.

31. The network device according to claim 30, wherein: The voltage zero-crossing data also includes the zero-crossing count value of the voltage zero-crossing, and the second information also includes the zero-crossing count value of the third zero-crossing. The zero-crossing count value of the third zero-crossing is used by the terminal device to determine the zero-crossing count value of the fourth zero-crossing.

32. The network device according to claim 30, wherein: The timestamp of the third zero-crossing point is also used by the terminal device to calibrate the local time.

33. The network device according to any one of claims 25-26, characterized in that: The network device further includes: The acquiring unit is configured to acquire the reference time before the generating unit generates the data of the voltage zero-crossing point according to the reference time.

34. A network device, characterized in that: The network device is applied to a PLC network, the network device is a first tail-end node, the PLC network further includes a head-end node connected to the first tail-end node, and the network device includes: a receiving unit, configured to receive first information sent by the headend node when a first timing time arrives, the first information including a timestamp of a first zero-crossing point, the timestamp of the first zero-crossing point being a zero-crossing point time of voltage zero-crossing points generated by the headend node based on a reference time, the zero-crossing point time having the shortest interval with the first timing time; A determining unit is configured to determine a zero-crossing time of a second zero-crossing point based on a timestamp of the first zero-crossing point in the first information received by the receiving unit.

35. The network device according to claim 34, wherein: When the first zero-crossing point and the second zero-crossing point are the same, the zero-crossing time of the second zero-crossing point is the same as the timestamp of the first zero-crossing point.

36. The network device according to claim 34 or 35, characterized in that: The first information also includes the zero-crossing count value of the first zero-crossing point. The determining unit is further configured to determine the zero-crossing count value of the second zero-crossing point according to the zero-crossing count value of the first zero-crossing point after the receiving unit receives the first information sent by the head-end node when the first timing time arrives.

37. The network device according to claim 36, characterized in that When the second zero-crossing point is the same as the first zero-crossing point, the zero-crossing count value of the second zero-crossing point is the same as the zero-crossing count value of the first zero-crossing point.

38. The network device according to any one of claims 34-35, characterized in that: The network device further includes: The calibration unit is configured to calibrate the local time according to the timestamp of the first zero-crossing point after the receiving unit receives the first information sent by the head-end node when the first timing time arrives.

39. The network device according to any one of claims 34-35, characterized in that: The network device is connected to the terminal device, and the network device further includes: a generating unit, configured to generate voltage zero-crossing data according to the zero-crossing time of the second zero-crossing point after the determining unit determines the zero-crossing time of the second zero-crossing point according to the timestamp of the first zero-crossing point, wherein the voltage zero-crossing data includes the zero-crossing time of the voltage zero-crossing point; A sending unit is used to send second information to the terminal device when the second timing time arrives, the second information includes a timestamp of a third zero-crossing point, the timestamp of the third zero-crossing point is the zero-crossing time of the voltage zero-crossing point generated by the generating unit with the smallest time interval with the second timing time, and the timestamp of the third zero-crossing point is used by the terminal device to determine the zero-crossing time of the fourth zero-crossing point.

40. The network device according to claim 39, wherein: The voltage zero-crossing data also includes the zero-crossing count value of the voltage zero-crossing, and the second information also includes the zero-crossing count value of the third zero-crossing. The zero-crossing count value of the third zero-crossing is used by the terminal device to determine the zero-crossing count value of the fourth zero-crossing.

41. The network device according to claim 39, wherein: The timestamp of the third zero-crossing point is also used by the terminal device to calibrate the local time.

42. The network device according to claim 39, wherein: The sending unit is also used to send third information to the second tail end node when the third timing time arrives, and the third information includes the timestamp of the fifth zero crossing point. The timestamp of the fifth zero crossing point is the zero crossing time of the voltage zero crossing point generated by the generating unit, and the zero crossing time with the smallest time interval with the third timing time. The timestamp of the fifth zero crossing point is used by the second tail end node to determine the zero crossing time of the sixth zero crossing point.

43. The network device according to claim 42, wherein: The voltage zero-crossing data also includes a zero-crossing count value of the voltage zero-crossing, and the third information also includes a zero-crossing count value of the fifth zero-crossing. The zero-crossing count value of the fifth zero-crossing is used by the second tail node to determine the zero-crossing count value of the sixth zero-crossing.

44. A terminal device, characterized in that: The terminal device is applied to a PLC network, the PLC network including a head-end node and at least one tail-end node connected to the head-end node, at least one of the head-end node and the at least one tail-end node being connected to at least one terminal device, the terminal device including: a receiving unit, configured to receive first information sent by a first node when a first timing time arrives, the first information including a timestamp of a first zero-crossing point, where the timestamp of the first zero-crossing point is a zero-crossing point time of a voltage zero-crossing point generated by the first node with the shortest time interval between the first timing time and the zero-crossing point time; A determining unit is configured to determine a timestamp of a second zero-crossing point according to the timestamp of the first zero-crossing point in the information received by the receiving unit.

45. The terminal device according to claim 44, characterized in that When the first node is the head-end node, the zero-crossing time of the voltage zero-crossing point is generated by the first node according to a reference time.

46. The terminal device according to claim 44, characterized in that When the first node is the tail node, the zero-crossing time of the voltage zero-crossing point is generated by the first node based on the timestamp of the third zero-crossing point, the timestamp of the third zero-crossing point is sent by the second node to the first node when the second timing time arrives, and the timestamp of the third zero-crossing point is the zero-crossing time with the smallest time interval between the timestamp of the voltage zero-crossing point generated by the second node and the second timing time.

47. The terminal device according to any one of claims 44 to 46, characterized in that: The first information also includes a zero-crossing count value of the first zero-crossing point, The determining unit is further configured to determine the zero-crossing count value of the second zero-crossing point according to the zero-crossing count value of the first zero-crossing point.

48. The terminal device according to any one of claims 44 to 46, characterized in that: The terminal device further includes: A calibration unit is configured to calibrate the local time according to the timestamp of the first zero-crossing point after the receiving unit receives the first information sent by the first node when the first timing time arrives.

49. A network device, characterized in that Including: processor, memory; The memory is used to store computer-readable instructions or computer programs, and the processor is used to read the computer-readable instructions or the computer program to implement the method according to any one of claims 1 to 9 or any one of claims 10 to 19.

50. A PLC device, characterized in that: Including: processor, memory; The memory is used to store computer-readable instructions or computer programs, and the processor is used to read the computer-readable instructions or the computer program to implement the method according to any one of claims 1 to 9 or any one of claims 10 to 19.

51. A chip system, characterized in that: The method comprises a processor configured to execute the method according to any one of claims 1 to 9 or any one of claims 10 to 19.

52. A terminal device, characterized in that: Including: processor, memory; The memory is used to store computer-readable instructions or computer programs, and the processor is used to read the computer-readable instructions or the computer program to implement the method according to any one of claims 20 to 24.

53. A computer-readable storage medium, characterized in that The method comprises computer program instructions, which, when executed on a computer, cause the computer to execute any one of claims 1 to 9 or the method according to any one of claims 10 to 19.

54. A computer-readable storage medium, characterized in that The method comprises computer program instructions which, when executed on a computer, cause the computer to perform the method according to any one of claims 20 to 24.

55. A PLC communication system, characterized in that: comprising a head-end node and at least one tail-end node connected to the head-end node, The head-end node is the head-end node described in any one of claims 25 to 33; The at least one tail end node comprises the first tail end node according to any one of claims 34 to 43.

56. The PLC communication system according to claim 55, characterized in that: The PLC communication system further includes at least one terminal device, and at least one of the head-end node and the at least one tail-end node is connected to the at least one terminal device. The terminal device is the terminal device described in any one of claims 44 to 48.

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