CN113950140A - Clock synchronization method and system for low-voltage distribution network Internet of things - Google Patents
Clock synchronization method and system for low-voltage distribution network Internet of things Download PDFInfo
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- H04W56/001—Synchronization between nodes
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Abstract
The invention relates to the technical field of communication of the Internet of things, and discloses a clock synchronization method and a system of the Internet of things of a low-voltage distribution network, wherein a full frequency band is used between a transformer and a user side as a carrier frequency band of a carrier communication channel, after a first communication device sends a carrier signal carrying a clock signal to a second communication device, the second communication device obtains the receiving time corresponding to each subcarrier signal, determines the receiving lag time according to the timing period of a vibration timer of the second communication device, compensates the corresponding clock signal by using the receiving lag time, if the clock information of the second communication device is not matched with the received clock signal, uses the compensated clock signal as the clock information of the second communication device, transmits the clock information to lower-layer equipment by an optical fiber in an optical signal mode to complete clock synchronization by using an optical fiber signal, therefore, the influence of environmental interference on clock synchronization can be reduced to the maximum extent, and the clock synchronization accuracy is improved.
Description
Technical Field
The invention relates to the technical field of communication of internet of things, in particular to a clock synchronization method and system for the internet of things of a low-voltage distribution network.
Background
With the continuous development of power grid construction, a power line carrier technology is used as a main communication means of a low-voltage distribution network, the prior art only supports metering services and cannot meet various requirements of intelligent operation and maintenance, system operation, a power market, intelligent scheduling, user side interaction and the like, the defects of station areas and user household internal services cannot be considered in a mainstream power line carrier communication mode, the traditional narrow-band carrier communication is mainly used for automatic meter reading services and cannot exert the advantages of wide carrier communication distribution and low cost, along with the construction of the ubiquitous power internet of things, the power line carrier communication is used as the most extensive communication mode in the power system communication and is also a basic communication means in the power system, the power line carrier communication can play an important role in the multi-service bearing technology of the low-voltage distribution network, in the construction of the low-voltage distribution network, clock synchronization is an important ring, and is the basis for the development of various services, most of the clock synchronization methods in the prior art are realized based on wireless transmission technology and single-frequency-band carrier communication.
At present, a chinese patent with an authorization publication number CN 106888503 a discloses a time calibration method for a radio and television frequency spectrum ultra-narrow band internet of things, which is applied to a mobile terminal and includes the following steps: sending an uplink calibration signal including first time information to the base station through a pre-established broadcast and television frequency spectrum ultra-narrow band communication system; monitoring all frequency bands of a broadcasting and television frequency spectrum ultra-narrow band communication system, and acquiring a downlink calibration signal which is sent by a base station through the broadcasting and television frequency spectrum ultra-narrow band communication system and comprises second time information; adjusting a clock of a controller of the mobile terminal according to the second time information so as to synchronize the time of the mobile terminal and the time of the base station; and repeating the steps until the time of the uplink process and the time of the downlink process of the base station and the mobile terminal are kept synchronous.
The above prior art solutions have the following drawbacks: the frequency band resources are not used properly, time consumption is high for monitoring all frequency bands, and inaccurate signal transmission is easily caused; meanwhile, when uplink and downlink time information is synchronized, the time delay of signal transmission is not considered, so that the clock synchronization is inaccurate.
Disclosure of Invention
The invention provides a clock synchronization method and system for an Internet of things of a low-voltage distribution network, which are used for solving the technical problems of inaccurate signal transmission and inaccurate clock synchronization.
In view of this, a first aspect of the present invention provides a clock synchronization method for an internet of things of a low-voltage distribution network, which is implemented based on two power line carrier communication devices, where the two power line carrier communication devices are respectively installed on a transformer side and a user side, the power line carrier communication device installed on the transformer side is defined as a first communication device, the first communication device is used as a clock reference, and the power line carrier communication device installed on the user side is defined as a second communication device, and the method includes the following steps:
step one, a carrier communication channel is established between the first communication device and the second communication device, and a full frequency band is used as a carrier frequency band of the carrier communication channel;
dividing the full frequency band to obtain a plurality of different sub-frequency bands, and respectively allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule;
step three, the first communication device and the second communication device are both provided with oscillation timers, the oscillation timers are used for providing timing periods, when the timing periods of the oscillation timers of the first communication device return to zero, the first communication device sends carrier signals to the second communication device, the carrier signals are composed of sub-carrier signals of a plurality of different sub-frequency bands, each sub-carrier signal carries a clock signal, and the clock signals carried by each sub-carrier signal are kept consistent;
step four, when the second communication device receives the carrier signals, acquiring the receiving time corresponding to each subcarrier signal, and performing difference processing on the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal to obtain the receiving lag time of each subcarrier signal;
judging whether the receiving lag time of each subcarrier signal exceeds the timing period of a half oscillation timer, and if the receiving lag time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by using the receiving lag time;
step six, acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with the received clock signal, and if not, updating the clock information into the compensated clock signal;
and seventhly, electro-optically converting the updated clock information into an optical signal, and outputting the optical signal to the lower-layer Internet of things equipment terminal through an optical fiber so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
Preferably, quantum coding and genetic algorithms are adopted to respectively allocate a plurality of subcarrier channels for each frequency sub-band.
Preferably, the timing frequency of the oscillation timer in the third step is smaller than the average frequency of the maximum frequency band in the full frequency band and is greater than the average frequency of the minimum frequency band in the full frequency band.
Preferably, the method further comprises:
establishing a wireless communication connection relation between the first communication device and the second communication device, generating a fault early warning signal if the second communication device does not receive the carrier signal sent by the first communication device, and sending the fault early warning signal to the first communication device wirelessly for warning based on the wireless communication connection relation.
Preferably, the method further comprises:
and when detecting that the carrier communication channel generates signal distortion, re-executing the step two.
Preferably, the method further comprises:
acquiring a topological connection relation of a transformer area, wherein the topological connection relation of the transformer area comprises a transformer and user equipment connected with the transformer;
acquiring historical marketing data with time sequence based on a power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by a transformer;
based on the topological connection relation of the transformer area, acquiring the time-varying period of the number of the user equipment accessed by the transformer through the historical marketing data, and dividing the time-varying period of the number of the user equipment into an idle period and a busy period according to a preset value of the number of the user equipment, wherein the number of the user equipment accessed by the transformer in the busy period is larger than that of the user equipment accessed in the idle period;
and executing the second step in an idle time period.
In a second aspect, the present invention further provides a clock synchronization system for a low-voltage distribution network internet of things, which is implemented based on two power line carrier communication devices, where the two power line carrier communication devices are respectively installed on a transformer side and a user side, the power line carrier communication device installed on the transformer side is defined as a first communication device, the first communication device is used as a clock reference, and the power line carrier communication device installed on the user side is defined as a second communication device, and the system includes:
a carrier communication module, configured to establish a carrier communication channel between the first communication device and the second communication device, and use a full frequency band as a carrier frequency band of the carrier communication channel;
the frequency band allocation module is used for dividing the full frequency band to obtain a plurality of different sub-frequency bands and allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule;
the first communication device and the second communication device are both provided with oscillation timers which are used for providing timing periods; the oscillation timer of the first communication device is configured to send a carrier signal to the second communication device when a timing cycle of the oscillation timer is zero, where the carrier signal is composed of multiple sub-carrier signals of different sub-frequency bands, each sub-carrier signal carries a clock signal, and the clock signals carried by each sub-carrier signal are kept consistent;
the second communication device is used for acquiring the receiving time corresponding to each subcarrier signal when receiving the carrier signal, and obtaining the receiving lag time of each subcarrier signal by performing difference processing on the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal;
the clock compensation module is used for judging whether the receiving lag time of each subcarrier signal exceeds the timing period of a half oscillation timer or not, and if the receiving lag time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by using the receiving lag time;
the clock updating module is used for acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with the received clock signal or not, and updating the clock information into the compensated clock signal if the clock information is not matched with the received clock signal;
and the clock synchronization transmission module is used for electro-optically converting the updated clock information into an optical signal, and outputting the optical signal to the lower-layer Internet of things equipment terminal through an optical fiber so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
Preferably, the system further comprises:
a wireless transmission module, configured to establish a wireless communication connection relationship between the first communication device and the second communication device;
the second communication device is provided with an early warning module, and the early warning module is used for generating a fault early warning signal when the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device for warning based on the wireless communication connection relation.
Preferably, the system further comprises: and the carrier allocation module is used for repartitioning the full frequency band to obtain a plurality of different sub-frequency bands when detecting that the carrier communication channel has signal distortion, and allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule.
Preferably, the system further comprises:
the topology acquisition module is used for acquiring a distribution area topology connection relationship, wherein the distribution area topology connection relationship comprises a transformer and each user equipment connected with the transformer;
the marketing data acquisition module is used for acquiring historical marketing data with time sequence based on the power marketing center, and the historical marketing data comprises the number of user equipment accessed by the transformer;
the time interval dividing module is used for acquiring the time-varying period of the number of the user equipment accessed by the transformer through the historical marketing data based on the topological connection relation of the transformer area, and is also used for dividing the time-varying period of the number of the user equipment into an idle time interval and a busy time interval according to a preset value of the number of the user equipment, wherein the number of the user equipment accessed by the transformer in the busy time interval is greater than that in the idle time interval;
the frequency band allocation module is further configured to divide the full frequency band in the idle period to obtain a plurality of different sub-frequency bands, and is further configured to allocate a plurality of subcarrier channels to each sub-frequency band in the idle period according to a preset allocation rule.
According to the technical scheme, the invention has the following advantages:
the invention can select the frequency band with better carrier channel by using the full frequency band between the transformer and the user side as the carrier frequency band of the carrier communication channel and respectively distributes a plurality of sub-carrier channels for each sub-frequency band according to the preset distribution rule, thereby improving the accuracy of carrier communication information transmission, after the first communication device sends the carrier signal with clock signal to the second communication device, the second communication device obtains the receiving time corresponding to each sub-carrier signal and determines the receiving lag time according to the timing period of the oscillation timer of the second communication device, if the receiving lag time exceeds the timing period of half the oscillation timer, the corresponding clock signal is compensated by using the receiving lag time, and whether the clock information of the second communication device is matched with the received clock signal is judged, if not, the compensated clock signal is used as the clock information of the second communication device, the clock information is transmitted to the lower-layer equipment through the optical fiber in an optical signal mode, and the clock synchronization is completed by using the optical fiber signal, so that the influence of environmental interference on the clock synchronization can be reduced to the maximum extent, and the clock synchronization accuracy is improved.
Drawings
Fig. 1 is a schematic structural diagram of a power line carrier communication apparatus according to an embodiment of the present invention;
fig. 2 is a flowchart of a clock synchronization method for the internet of things of the low-voltage distribution network according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The clock synchronization method for the Internet of things of the low-voltage distribution network is realized based on two power line carrier communication devices, as shown in fig. 1, the two power line carrier communication devices are respectively installed on a transformer side and a user side, the power line carrier communication device installed on the transformer side is defined as a first communication device, the first communication device is used as a clock reference, and the power line carrier communication device installed on the user side is defined as a second communication device.
As shown in fig. 2, the method comprises the following steps:
step one, a carrier communication channel is established between a first communication device and a second communication device, and a full frequency band is used as a carrier frequency band of the carrier communication channel.
The full-band carrier communication can better exert carrier performance and support more power services, and in the construction of an actual internet of things, the full-band carrier communication can meet the communication requirements of a station area and user side equipment and can also meet the requirements of layered power line carrier communication.
And step two, dividing the full frequency band to obtain a plurality of different sub-frequency bands, and respectively allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule.
In one embodiment, quantum coding and genetic algorithms are used to allocate a number of sub-carrier channels to each sub-band.
The quantum coding and genetic algorithm are the prior art, and can solve the problem of subcarrier distribution during multiple access by utilizing the quantum coding and genetic algorithm, so that the communication is ensured to be kept smooth after a plurality of power equipment are accessed into the transformer, and the accuracy of clock synchronization is realized.
The number of the sub-carrier signals allocated to each sub-band is three, and taking power frequency carrier communication, an intermediate frequency narrow band and a high frequency narrow band as an example, under the condition that the environment of a carrier communication channel is stable, the arrival time of the sub-carrier signals of different frequency bands should be consistent, and the arrival time of the sub-carrier has a certain interval (but the interval is small) in consideration of the fluctuation of the actual environment.
Because the carrier frequency bands used as the carrier communication channels are different, the frequency band with the better carrier channel can be selected by allocating the sub-carrier channels, and the accuracy of carrier communication information transmission can be improved.
And step three, the first communication device and the second communication device are respectively provided with an oscillation timer, the oscillation timers are used for providing timing periods, when the timing periods of the oscillation timers of the first communication device return to zero, the first communication device sends carrier signals to the second communication device, the carrier signals are composed of sub-carrier signals of a plurality of different sub-frequency bands, each sub-carrier signal carries a clock signal, and the clock signals carried by each sub-carrier signal are kept consistent.
The timing frequency of the oscillation timer in the third step is less than the average frequency of the maximum frequency band in the full frequency band and greater than the average frequency of the minimum frequency band in the full frequency band, and the frequency of the timing period is within the range of the frequency band of the subcarrier, so that the delay difference of carrier signal transmission can be correctly measured.
Wherein the clock signal is acquired when the carrier signal is transmitted based on a system clock of the first communication device.
And step four, when the second communication device receives the carrier signals, acquiring the receiving time corresponding to each subcarrier signal, and performing difference processing on the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal to obtain the receiving lag time of each subcarrier signal.
In a specific embodiment, after obtaining the difference between the timing period of the oscillation timer and the receiving time corresponding to each subcarrier signal, the average value of the sum of all the differences is taken as the receiving delay time, so as to improve the accuracy of the calculation.
The carrier communication receiving circuit in the second communication device is provided with a function of recording the receiving time when receiving the carrier signal. Meanwhile, the periodic frequencies of the oscillation timers of the first communication device and the second communication device are consistent.
And step five, judging whether the receiving lag time of each subcarrier signal exceeds the timing period of a half oscillation timer, and if the receiving lag time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by using the receiving lag time.
And step six, acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with the received clock signal, and if not, updating the clock information into the compensated clock signal.
The clock information is system clock information of the second communication device, and if the clock information does not match the received clock signal (the error is greater than a predetermined threshold), it indicates that the system clock of the second communication device is not synchronous, and the clock signal needs to be covered with the clock information.
If the clock information matches the received clock signal, the original clock information can be used.
And seventhly, electro-optically converting the updated clock information into an optical signal, and outputting the optical signal to the lower-layer Internet of things equipment terminal through an optical fiber so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
The clock information is an electrical signal, correct clock information is converted into an optical signal, and the optical signal is transmitted to the equipment through the optical fiber.
In one embodiment, the method further comprises:
the method comprises the steps that a wireless communication connection relation is established between a first communication device and a second communication device, if the second communication device does not receive a carrier signal sent by the first communication device, a fault early warning signal is generated, and the fault early warning signal is sent to the first communication device in a wireless mode to give an alarm based on the wireless communication connection relation.
When the first communication device transmits the carrier communication signal, the first communication device simultaneously transmits the wireless signal, and the wireless signal is not normally used for clock synchronization because of a large delay of the wireless signal.
In another embodiment, after the carrier communication fails, the first communication device sends a wireless signal for clock synchronization, and because the wireless signal has a large delay, both the first communication device and the second communication device are provided with GPS positioning modules for ranging, and the measured distance is used for calculating and correcting the delay of the signal transmitted by the wireless transmission module, and the delay is corrected according to the positive correlation between the distance and the delay.
In the embodiment, the timing period of the oscillation timer is used for recording the signal transmission delay, so that the accuracy of the clock signal is ensured, and meanwhile, under the condition that the carrier communication fault is invalid, the clock synchronism can be ensured through wireless signal transmission.
In one embodiment, the method further comprises:
and when detecting that the carrier communication channel generates signal distortion, re-executing the step two.
It should be noted that, when external environment interference, device switching, and other factors cause a change in the environment of the carrier communication channel, the channel gain changes accordingly, and the delay of signal transmission changes accordingly, so that signal distortion occurs in the carrier communication channel, that is, when the frequency band of the subcarrier is not the optimal frequency band, the subcarrier channel needs to be reallocated, and then clock synchronization is performed again, thereby reducing errors.
And when the environment of the carrier communication channel is kept stable, performing clock synchronization regularly, and performing clock synchronization again after a certain number of periods is reached according to the number of the timing periods of the oscillation timer.
In one embodiment, the method further comprises:
acquiring a topological connection relation of a transformer area, wherein the topological connection relation of the transformer area comprises the transformer and each user equipment connected with the transformer;
acquiring historical marketing data with time sequence based on a power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by a transformer;
based on the topological connection relation of the transformer area, acquiring the time-varying period of the number of user equipment accessed by the transformer through historical marketing data, and dividing the time-varying period of the number of user equipment into an idle period and a busy period according to a preset value of the number of user equipment, wherein the number of the user equipment accessed by the transformer in the busy period is larger than that of the user equipment accessed in the idle period;
and step two is executed in an idle time period.
It should be noted that the number of the transformer access electric devices changes with time and has a certain periodic rule, the idle time and the busy time can be determined according to the device access cycle, and the number of the transformer access user devices in the busy time is greater than that of the transformer access user devices in the idle time, so that the idle time can be preferentially selected to avoid the busy time during allocation, thereby increasing the sub-carrier allocation speed and facilitating the establishment of a stable high-quality carrier communication channel.
The invention provides a clock synchronization method for an Internet of things of a low-voltage distribution network, which can improve the accuracy of carrier communication information transmission by using a full frequency band between a transformer and a user side as a carrier frequency band of a carrier communication channel and respectively allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule, can select a frequency band with a better carrier channel, obtains the receiving time corresponding to each sub-carrier signal by a second communication device after a first communication device sends a carrier signal carrying a clock signal to the second communication device, determines the receiving lag time according to the timing period of an oscillation timer of the second communication device, compensates the corresponding clock signal by using the receiving lag time if the receiving lag time exceeds the timing period of a half oscillation timer, and also judges whether the clock information of the second communication device is matched with the received clock signal, if not, the compensated clock signal is used as the clock information of the second communication device, the clock information is transmitted to the lower-layer equipment through the optical fiber in an optical signal mode, and the clock synchronization is completed by using the optical fiber signal, so that the influence of environmental interference on the clock synchronization can be reduced to the maximum extent, and the clock synchronization accuracy is improved.
The invention also provides a clock synchronization system of the internet of things of a low-voltage distribution network, which is realized based on two power line carrier communication devices, as shown in fig. 1, the two power line carrier communication devices are respectively arranged at a transformer side and a user side, the power line carrier communication device arranged at the transformer side is defined as a first communication device, the first communication device is used as a clock reference, the power line carrier communication device arranged at the user side is defined as a second communication device, and the system comprises:
the carrier communication module is used for establishing a carrier communication channel between the first communication device and the second communication device and taking a full frequency band as a carrier frequency band of the carrier communication channel;
the frequency band allocation module is used for dividing a full frequency band to obtain a plurality of different sub-frequency bands and allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule;
and a plurality of subcarrier channels are respectively distributed to each sub-frequency band by adopting quantum coding and a genetic algorithm.
The first communication device and the second communication device are both provided with oscillation timers which are used for providing timing periods; the oscillation timer of the first communication device is used for sending a carrier signal to the second communication device when the timing period of the oscillation timer is zero, wherein the carrier signal is composed of a plurality of sub-carrier signals of different sub-frequency bands, each sub-carrier signal carries a clock signal, and the clock signals carried by each sub-carrier signal are kept consistent;
the timing frequency of the oscillation timer in the third step is less than the average frequency of the maximum frequency band in the full frequency band and greater than the average frequency of the minimum frequency band in the full frequency band.
The second communication device is used for acquiring the receiving time corresponding to each subcarrier signal when receiving the carrier signal, and obtaining the receiving lag time of each subcarrier signal by performing difference processing on the timing period of an oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal;
the clock compensation module is used for judging whether the receiving lag time of each subcarrier signal exceeds the timing period of a half oscillation timer or not, and if the receiving lag time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by using the receiving lag time;
the clock updating module is used for acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with the received clock signal or not, and updating the clock information into a compensated clock signal if the clock information is not matched with the received clock signal;
and the clock synchronization transmission module is used for performing electro-optical conversion on the updated clock information into an optical signal, and outputting the optical signal to the lower-layer Internet of things equipment terminal through an optical fiber so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
In one embodiment, the system further comprises:
the wireless transmission module is used for establishing a wireless communication connection relationship between the first communication device and the second communication device;
the second communication device is provided with an early warning module, and the early warning module is used for generating a fault early warning signal when the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device for warning based on the wireless communication connection relation.
In one embodiment, the system further comprises: and the carrier allocation module is used for repartitioning the full frequency band to obtain a plurality of different sub-frequency bands when detecting that the carrier communication channel has signal distortion, and allocating a plurality of sub-carrier channels for each sub-frequency band according to a preset allocation rule.
In one embodiment, the system further comprises:
the topology acquisition module is used for acquiring a distribution area topology connection relationship, and the distribution area topology connection relationship comprises a transformer and each user equipment connected with the transformer;
the marketing data acquisition module is used for acquiring historical marketing data with time sequence based on the power marketing center, and the historical marketing data comprises the number of user equipment accessed by the transformer;
the time interval dividing module is used for acquiring the time-varying period of the number of the user equipment accessed by the transformer through historical marketing data based on the topological connection relation of the transformer area, and dividing the time-varying period of the number of the user equipment into an idle time interval and a busy time interval according to a preset value of the number of the user equipment, wherein the number of the transformer accessed into the user equipment in the busy time interval is larger than that of the user equipment in the idle time interval;
and the frequency band allocation module is also used for dividing the full frequency band in the idle time band to obtain a plurality of different sub-frequency bands and allocating a plurality of subcarrier channels to each sub-frequency band in the idle time band according to a preset allocation rule.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a unit is merely a logical division, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A clock synchronization method for the Internet of things of a low-voltage distribution network is realized based on two power line carrier communication devices, wherein the two power line carrier communication devices are respectively arranged on a transformer side and a user side, the power line carrier communication device arranged on the transformer side is defined as a first communication device, the first communication device is used as a clock reference, and the power line carrier communication device arranged on the user side is defined as a second communication device, and the clock synchronization method is characterized by comprising the following steps:
step one, a carrier communication channel is established between the first communication device and the second communication device, and a full frequency band is used as a carrier frequency band of the carrier communication channel;
dividing the full frequency band to obtain a plurality of different sub-frequency bands, and respectively allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule;
step three, the first communication device and the second communication device are both provided with oscillation timers, the oscillation timers are used for providing timing periods, when the timing periods of the oscillation timers of the first communication device return to zero, the first communication device sends carrier signals to the second communication device, the carrier signals are composed of sub-carrier signals of a plurality of different sub-frequency bands, each sub-carrier signal carries a clock signal, and the clock signals carried by each sub-carrier signal are kept consistent;
step four, when the second communication device receives the carrier signals, acquiring the receiving time corresponding to each subcarrier signal, and performing difference processing on the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal to obtain the receiving lag time of each subcarrier signal;
judging whether the receiving lag time of each subcarrier signal exceeds the timing period of a half oscillation timer, and if the receiving lag time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by using the receiving lag time;
step six, acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with the received clock signal, and if not, updating the clock information into the compensated clock signal;
and seventhly, electro-optically converting the updated clock information into an optical signal, and outputting the optical signal to the lower-layer Internet of things equipment terminal through an optical fiber so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
2. The clock synchronization method for the Internet of things of the low-voltage distribution network according to claim 1, wherein a plurality of subcarrier channels are respectively allocated to each sub-frequency band by adopting quantum coding and a genetic algorithm.
3. The clock synchronization method for the internet of things of the low-voltage distribution network according to claim 1, wherein the timing frequency of the oscillation timer in the third step is smaller than the average frequency of the maximum frequency band in the full frequency band and larger than the average frequency of the minimum frequency band in the full frequency band.
4. The clock synchronization method for the Internet of things of the low-voltage distribution network according to claim 1, further comprising the following steps of:
establishing a wireless communication connection relation between the first communication device and the second communication device, generating a fault early warning signal if the second communication device does not receive the carrier signal sent by the first communication device, and sending the fault early warning signal to the first communication device wirelessly for warning based on the wireless communication connection relation.
5. The clock synchronization method for the Internet of things of the low-voltage distribution network according to claim 1, further comprising the following steps of:
and when detecting that the carrier communication channel generates signal distortion, re-executing the step two.
6. The clock synchronization method for the Internet of things of the low-voltage distribution network according to claim 1, further comprising the following steps of:
acquiring a topological connection relation of a transformer area, wherein the topological connection relation of the transformer area comprises a transformer and user equipment connected with the transformer;
acquiring historical marketing data with time sequence based on a power marketing center, wherein the historical marketing data comprises the number of user equipment accessed by a transformer;
based on the topological connection relation of the transformer area, acquiring the time-varying period of the number of the user equipment accessed by the transformer through the historical marketing data, and dividing the time-varying period of the number of the user equipment into an idle period and a busy period according to a preset value of the number of the user equipment, wherein the number of the user equipment accessed by the transformer in the busy period is larger than that of the user equipment accessed in the idle period;
and executing the second step in an idle time period.
7. The utility model provides a net thing networking clock synchronization system is joined in marriage to low pressure, realizes based on two power line carrier communication device, two power line carrier communication device installs respectively in transformer side and user side, install in the transformer side power line carrier communication device defines to first communication device, first communication device is used for as the clock benchmark, installs at the user side power line carrier communication device defines to the second communication device, its characterized in that, its system includes:
a carrier communication module, configured to establish a carrier communication channel between the first communication device and the second communication device, and use a full frequency band as a carrier frequency band of the carrier communication channel;
the frequency band allocation module is used for dividing the full frequency band to obtain a plurality of different sub-frequency bands and allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule;
the first communication device and the second communication device are both provided with oscillation timers which are used for providing timing periods; the oscillation timer of the first communication device is configured to send a carrier signal to the second communication device when a timing cycle of the oscillation timer is zero, where the carrier signal is composed of multiple sub-carrier signals of different sub-frequency bands, each sub-carrier signal carries a clock signal, and the clock signals carried by each sub-carrier signal are kept consistent;
the second communication device is used for acquiring the receiving time corresponding to each subcarrier signal when receiving the carrier signal, and obtaining the receiving lag time of each subcarrier signal by performing difference processing on the timing period of the oscillation timer of the second communication device and the receiving time corresponding to each subcarrier signal;
the clock compensation module is used for judging whether the receiving lag time of each subcarrier signal exceeds the timing period of a half oscillation timer or not, and if the receiving lag time exceeds the timing period of the half oscillation timer, compensating the corresponding clock signal by using the receiving lag time;
the clock updating module is used for acquiring corresponding clock information based on a system clock of the second communication device, judging whether the clock information is matched with the received clock signal or not, and updating the clock information into the compensated clock signal if the clock information is not matched with the received clock signal;
and the clock synchronization transmission module is used for electro-optically converting the updated clock information into an optical signal, and outputting the optical signal to the lower-layer Internet of things equipment terminal through an optical fiber so as to realize clock synchronization of the lower-layer Internet of things equipment terminal.
8. The low-voltage distribution network internet of things clock synchronization system of claim 7, further comprising:
a wireless transmission module, configured to establish a wireless communication connection relationship between the first communication device and the second communication device;
the second communication device is provided with an early warning module, and the early warning module is used for generating a fault early warning signal when the second communication device does not receive the carrier signal sent by the first communication device, and wirelessly sending the fault early warning signal to the first communication device for warning based on the wireless communication connection relation.
9. The low-voltage distribution network internet of things clock synchronization system of claim 7, further comprising: and the carrier allocation module is used for repartitioning the full frequency band to obtain a plurality of different sub-frequency bands when detecting that the carrier communication channel has signal distortion, and allocating a plurality of sub-carrier channels to each sub-frequency band according to a preset allocation rule.
10. The low-voltage distribution network internet of things clock synchronization system of claim 7, further comprising:
the topology acquisition module is used for acquiring a distribution area topology connection relationship, wherein the distribution area topology connection relationship comprises a transformer and each user equipment connected with the transformer;
the marketing data acquisition module is used for acquiring historical marketing data with time sequence based on the power marketing center, and the historical marketing data comprises the number of user equipment accessed by the transformer;
the time interval dividing module is used for acquiring the time-varying period of the number of the user equipment accessed by the transformer through the historical marketing data based on the topological connection relation of the transformer area, and is also used for dividing the time-varying period of the number of the user equipment into an idle time interval and a busy time interval according to a preset value of the number of the user equipment, wherein the number of the user equipment accessed by the transformer in the busy time interval is greater than that in the idle time interval;
the frequency band allocation module is further configured to divide the full frequency band in the idle period to obtain a plurality of different sub-frequency bands, and is further configured to allocate a plurality of subcarrier channels to each sub-frequency band in the idle period according to a preset allocation rule.
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| CN101610108A (en) * | 2009-07-15 | 2009-12-23 | 电信科学技术第一研究所 | Improve the method for digital spread spectrum receiver carrier phase jitter and wave distortion |
| CN102694762A (en) * | 2011-03-25 | 2012-09-26 | 北京新岸线无线技术有限公司 | Method for realizing synchronization of carrier and sampling clock, and user site device |
| CN109547146A (en) * | 2019-01-14 | 2019-03-29 | 北京邮电大学 | A kind of Wireless clock synchronous method and device based on super broad band radio communication |
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| CN101610108A (en) * | 2009-07-15 | 2009-12-23 | 电信科学技术第一研究所 | Improve the method for digital spread spectrum receiver carrier phase jitter and wave distortion |
| CN102694762A (en) * | 2011-03-25 | 2012-09-26 | 北京新岸线无线技术有限公司 | Method for realizing synchronization of carrier and sampling clock, and user site device |
| CN109547146A (en) * | 2019-01-14 | 2019-03-29 | 北京邮电大学 | A kind of Wireless clock synchronous method and device based on super broad band radio communication |
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