Radio frequency communication phase identification method based on G3-Hybrid communication network

Abstract

The invention belongs to the technical field of electric power communication, and particularly relates to a radio frequency communication phase identification method based on a G3-Hybrid communication network, which comprises the following steps: when a sender organizes a message, obtaining a time difference between a current moment and a previous zero crossing point, calculating a radio frequency sending PDC value, and packaging and sending the PDC value; the receiver obtains the time difference between the current moment and the last zero crossing point in the SFD link in the receiving process, determines a radio frequency receiving PDC value, and transmits the radio frequency receiving PDC value to the MAC layer for processing; the receiver calculates a radio frequency phase identification variable according to the radio frequency receiving PDC value and the radio frequency sending PDC value; determining a phase difference between the sender and the receiver; and determining the phase of the receiver. According to the invention, identification of phase information of all nodes of a G3 network topology structure can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power communication, and particularly relates to a radio frequency communication phase identification method based on a G3-Hybrid communication network. Background Art

[0002] With the continuous progress of smart grid technology, the carrier communication - radio frequency communication dual-mode communication centralized meter reading system plays an increasingly important role in the power system. As an international standard protocol in this field, the G3-Hybrid communication protocol has been widely applied worldwide. The G3-Hybrid communication network combines the advantages of carrier communication (PLC) and radio frequency communication (RF), and can perform stable and efficient data transmission in complex and diverse communication environments. The phase identification function plays an important role in the power centralized meter reading system. In a G3-Hybrid network substation area, the route can obtain the phase information of the nodes in the substation area according to the topological structure. However, the current G3 specification only provides a phase identification method for the carrier communication channel, which makes the G3-Hybrid communication network unable to achieve the phase identification of the radio frequency channel. In the G3-Hybrid network substation area, for some nodes that do not support carrier communication, the route cannot correctly identify the phase information of these nodes. This current situation limits the further application of the G3 radio frequency channel in the power system. Summary of the Invention

[0003] In order to solve the technical problem that the route in the G3-Hybrid network substation area in the prior art cannot identify the phase information of radio frequency signals, the present invention proposes a radio frequency communication phase identification method based on a G3-Hybrid communication network, accurately identifies the node phase information through the radio frequency channel, expands the phase identification function of the G3-Hybrid communication system, and provides important technical support for the further development and optimization of the power centralized meter reading communication system.

[0004] In order to solve the above technical problem, the technical solution adopted by the present invention is: a radio frequency communication phase identification method based on a G3-Hybrid communication network, comprising the following steps:

[0005] Step 1: When the sender organizes a message, obtain the time difference between the current moment and the last zero-crossing moment, calculate the radio frequency transmission PDC value after compensating the first time difference according to the current message length and the radio channel data rate, place the radio frequency transmission PDC value as an extended field into the data packet, and then the sender drives the radio frequency chip to complete the transmission of this message;

[0006] Step 2: The receiving party obtains the time difference from the previous zero crossing at the SFD stage in the receiving process, and determines the RF receiving PDC value according to the time difference from the previous zero crossing at the SFD stage in the receiving process, and transfers it to the MAC layer for processing;

[0007] Step 3: The receiving party calculates the RF phase identification variable according to the RF receiving PDC value Rx_PDC_RF and the RF transmitting PDC value Tx_PDC_RF. The calculation formula is:

[0008] PDC_dif_RF = Rx_PDC_RF - Tx_PDC_RF;

[0009] where PDC_dif_RF represents the RF phase identification variable, Tx_PDC_RF represents the RF transmitting PDC value, and Rx_PDC_RF represents the RF receiving PDC value;

[0010] Step 4: Determine the phase difference between the sending party and the receiving party according to the RF phase identification variable;

[0011] Step 5: Determine the phase of the sending party or the receiving party according to the phase difference between the sending party and the receiving party.

[0012] In the above Step 1, the calculation formula of the RF transmitting PDC value is:

[0013] Tx_PDC_RF = (zc tick + T1 + T2 + T3) / S;

[0014] where zc tick represents the time difference from the previous zero crossing at the current moment of the sending party, T1 represents the program execution time from the sending party obtaining the time difference zc tick to the physical layer sending function, T2 represents the sending party physical layer sending function time, T3 represents the time from the sending party sending completion to the receiving end SFD interruption, and S represents the time resolution of the unit PDC.

[0015] In the above Step 2, the calculation formula of the RF receiving PDC value is:

[0016] Rx_PDC_RF = zc tick2 / S;

[0017] where zc tick2 represents the time difference from the previous zero crossing at the SFD stage in the receiving process of the receiving party, and S represents the time resolution of the unit PDC.

[0018] The time resolution of the unit PDC is:

[0019] S = T / 256;

[0020] Among them, T represents the period of power frequency alternating current.

[0021] In the first step, when the sender organizes the message, the time difference from the last zero-crossing to the current moment is obtained through the internal software timer TIMER_1.

[0022] In the second step, in the SFD link of the receiving process, the receiver obtains the time difference from the last zero-crossing to the current moment through the internal software timer TIMER_1.

[0023] In the fourth step, the method for determining the phase difference between the sender and the receiver is as follows:

[0024] If the phase identification variable PDC_dif_RF belongs to the interval [0, 22) or the interval [232, 255], the phase difference between the sender and the receiver is 0;

[0025] If the phase identification variable PDC_dif_RF belongs to the interval [22, 64), the phase difference between the sender and the receiver is 1;

[0026] If the phase identification variable PDC_dif_RF belongs to the interval [64, 106), the phase difference between the sender and the receiver is 2;

[0027] If the phase identification variable PDC_dif_RF belongs to the interval [106, 148), the phase difference between the sender and the receiver is 3;

[0028] If the phase identification variable PDC_dif_RF belongs to the interval [148, 190), the phase difference between the sender and the receiver is 4;

[0029] If the phase identification variable PDC_dif_RF belongs to the interval [190, 232), the phase difference between the sender and the receiver is 5.

[0030] In the fourth step, it also includes the step of judging whether the radio frequency phase identification variable is negative. If it is negative, its value is added with 255 as the new radio frequency phase identification variable.

[0031] In the fifth step, the phase of the receiver is determined in combination with the phase mapping table.

[0032] The described radio frequency communication phase identification method based on the G3-Hybrid communication network further includes the following steps:

[0033] Step six: The router cascades to identify the phases of each multi-hop node according to its own phase and the phase differences between multi-hop nodes.

[0034] The present invention has the following beneficial effects compared with the prior art:

[0035] The present invention provides a radio frequency communication phase identification method based on a G3-Hybrid communication network. By identifying the phase of nodes through a wireless radio frequency channel, the phase identification function of nodes in the G3-Hybrid communication network is extended, enabling the routing to identify the phase information of all nodes, which provides important technical support for the further development and optimization of the power centralized meter reading communication system. Brief Description of the Drawings

[0036] Figure 1 It is a schematic flowchart of a radio frequency communication phase identification method based on a G3-Hybrid communication network proposed in Embodiment 1 of the present invention;

[0037] Figure 2 It is a schematic diagram of the principle of phase difference calculation in the embodiments of the present invention;

[0038] Figure 3 It is a schematic diagram of cascaded identification of phase difference;

[0039] Figure 4 It is a schematic diagram of the G3 network topology. Detailed Embodiments

[0040] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments and the accompanying drawings. Obviously, the described embodiments are some, rather than all, of the embodiments of the present invention; all other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0041] Embodiment 1

[0042] As Figure 1 shown, Embodiment 1 of the present invention provides a radio frequency communication phase identification method based on a G3-Hybrid communication network, including the following steps:

[0043] Step 1: When the sender organizes a message, obtain the time difference from the previous zero crossing at the current moment, perform compensation calculation on the first time difference according to the current message length and the wireless channel data rate to obtain the radio frequency transmission PDC value, place the radio frequency transmission PDC value as an extended field in the data packet, and then the sender drives the wireless radio frequency chip to complete the transmission of this message.

[0044] The communication module based on G3-Hybrid communication is equipped with a zero-crossing detection circuit. Modules within the same power distribution station will synchronize an internal software timer TIMER_1 based on the zero-crossing detection interrupt. According to the regulations regarding PLC phase identification in the G3 specification, a PDC (Phase Detection Counter) is used to represent the variable for phase identification. PDC is an unsigned char type variable. In China's 50Hz power frequency three-phase power supply system, the period is 20ms. Within a complete zero-crossing interruption cycle, PDC will increase from 0 to 255. Therefore, the time resolution of a single PDC is (20 / 256)ms.

[0045] In this embodiment, when the sender organizes the data packet structure at the MAC layer, it will obtain the time difference from the current moment to the last zero-crossing point based on TIMER_1, named zc_tick. Subsequently, after comprehensively considering the radio frequency chip processing flow and the actual operation of the system, an accurately calculated compensation value is added to zc_tick to generate Tx_PDC_RF. According to the 《IEEE

[0046] 802.15.4》 protocol, this data is placed in the data packet as an extended field. In the radio frequency message, according to the 《IEEE

[0047] 802.15.4》 technical standard, a manufacturer-defined information element IE field allowed by the specification is introduced to achieve the transmission of the Tx_PDC_RF parameter. This custom field follows the G3 specification and the 《IEEE 802.15.4》 technical standard, ensuring the compatibility of the technical implementation.

[0048] Therefore, in step one, when the sender organizes the message, it obtains the time difference from the current moment to the last zero-crossing point through the internal software timer TIMER_1.

[0049] In step one, the calculation formula for the radio frequency transmission PDC value is:

[0050] Tx_PDC_RF=(zc tick +T1+T2+T3) / S; (1)

[0051] Among them, Tx_PDC_RF represents the radio frequency transmission PDC value, zc tick represents the time difference from the current moment of the sender to the last zero-crossing point, and T1 represents the time difference zc taken from the sender tickThe program execution time to the physical layer sending function, T2 represents the time of the sender's physical layer sending function, T3 represents the time from the completion of sending by the sender to the SFD interruption at the receiver end, and S represents the time resolution of a unit PDC. Among them, the value of T1 is the program execution time of the fixed code segment and remains unchanged; the value of T2 is linearly related to the length of the sent message; the value of T3 is affected by the data rate configuration. Therefore, based on the currently used hardware and system, the above compensation times T1, T2, and T3 can be accurately determined through methods such as software timer and oscilloscope measurement.

[0052] Specifically, in this embodiment, the time resolution of a unit PDC is:

[0053] S = T / 256; (2)

[0054] Among them, T represents the cycle of industrial frequency alternating current, T = 20.0ms. In a complete zero-crossing interruption cycle, the PDC will increase from 0 to 255. Therefore, the time resolution of a unit PDC is (20 / 256)ms.

[0055] Step 2: The receiver obtains the time difference from the current moment to the last zero-crossing at the SFD link in the receiving process, and determines the radio frequency receiving PDC value according to the time difference from the SFD link in the receiving process to the last zero-crossing and passes it to the MAC layer for processing.

[0056] In the said Step 2, the receiver obtains the time difference from the current moment to the last zero-crossing through the internal software timer TIMER_1 at the SFD link in the receiving process.

[0057] In the said Step 2, the calculation formula for the radio frequency receiving PDC value Rx_PDC_RF is:

[0058] Rx_PDC_RF = zc tick2 / S; (3)

[0059] Among them, zc tick2 represents the time difference from the SFD link in the receiver's receiving process to the last zero-crossing, and S represents the time resolution of a unit PDC.

[0060] Step 3: The receiver calculates the radio frequency phase identification variable according to the radio frequency receiving PDC value Rx_PDC_RF and the radio frequency sending PDC value Tx_PDC_RF. The calculation formula is:

[0061] PDC_dif_RF = Rx_PDC_RF - Tx_PDC_RF; (4)

[0062] Among them, PDC_dif_RF represents the radio frequency phase identification variable, Tx_PDC_RF represents the radio frequency transmission PDC value, and Rx_PDC_RF represents the radio frequency reception PDC value. Each time the receiver receives a data packet, at the SFD interruption in the wireless radio frequency chip reception process, the time difference from the previous zero crossing to the current moment is obtained based on TIMER_1 as Rx_PDC_RF, and the Tx_PDC_RF in the data packet is read, and the phase difference between itself and the sender is calculated according to the algorithm.

[0063] Step 4: Determine the phase difference between the sender and the receiver according to the radio frequency phase identification variable.

[0064] The three-phase electricity on the power supply is a sine wave with a 120° phase shift from each other. According to the difference between Rx_PDC_RF and Tx_PDC_RF, the time difference between the positive zero crossings of the sender and the receiver can be deduced, and then the phase difference between the sender and the receiver can be deduced. Within a complete 360° zero crossing cycle, the radio frequency phase identification variable increases from 0 to 255, that is, for every 1° increase in phase, the value of the radio frequency phase identification variable increases by 0.711.

[0065] As Figure 2 shown, it is a schematic diagram of the phase difference calculation principle. There are three sine waves in the figure representing three phases respectively. The horizontal axis coordinate value is the phase difference degree, and there is a 120° phase shift between adjacent phases; the PDC_dif_RF values are marked below the coordinate axis according to the phase difference interval. The value range of PDC_dif_RF is [0, 255], which is divided into 7 intervals, namely: [0, 22), [22, 64), [64, 106), [106, 148), [148, 190), [190, 232), [232, 255]. The above 7 intervals correspond to 6 different PHS_dif_RF values, as shown in Table 1.

[0066] Table 1 Mapping table of PDC_dif_RF value and phase difference PHS_dif_RF

[0067] PDC_dif_RF PHS_dif_RF [0,22)[232,255] 0 [22,64) 1 [64,106) 2 [106,148) 3 [148,190) 4 [190,232) 5

[0068] Referring to Table 1, in the said Step 4, the method for determining the phase difference between the sender and the receiver is as follows:

[0069] If the phase identification variable PDC_dif_RF belongs to the interval [0, 22) or the interval [232, 255], then the phase difference between the sender and the receiver is 0;

[0070] If the phase identification variable PDC_dif_RF belongs to the interval [22, 64), then the phase difference between the sender and the receiver is 1;

[0071] If the phase identification variable PDC_dif_RF belongs to the interval [64, 106), the phase difference between the sender and the receiver is 2;

[0072] If the phase identification variable PDC_dif_RF belongs to the interval [106, 148), the phase difference between the sender and the receiver is 3;

[0073] If the phase identification variable PDC_dif_RF belongs to the interval [148, 190), the phase difference between the sender and the receiver is 4;

[0074] If the phase identification variable PDC_dif_RF belongs to the interval [190, 232), the phase difference between the sender and the receiver is 5.

[0075] In addition, in the fourth step, it also includes the step of judging whether the radio frequency phase identification variable is negative. If it is negative, add 255 to its value as the new radio frequency phase identification variable, that is:

[0076] PDC_dif_RF = PDC_dif_RF + 255. (5)

[0077] Step Five: Determine the phase of the receiver according to the sender's phase and the phase difference between the sender and the receiver.

[0078] Combined Figure 2 With Table 1, it is assumed that the sender sends a message at the positive zero-crossing moment of Phase A. After the receiver receives the message, it calculates the radio frequency phase identification variable PDC_dif_RF. If this value is in the interval [22, 64) or [148, 190), it proves that the phase where the receiver is located is two phases delayed compared to Phase A, that is, the receiver is in Phase C. At this time, the phase difference PHS_dif_RF value is 1 or 4; if this value is in the interval [64, 106) or [190, 232), it proves that the phase where the receiver is located is one phase delayed compared to Phase A, that is, the receiver is in Phase B. At this time, the phase difference PHS_dif_RF value is 2 or 5; if this value is in the interval [0, 22) or [232, 255], [106, 148), it proves that the phase where the receiver is located has no delay compared to Phase A, that is, the receiver is also in Phase A. At this time, the phase difference PHS_dif_RF value is 0 or 3. Therefore, by analogy, a phase mapping table that can reflect the mapping relationship between the phases of the sender and the receiver and the phase difference PHS_dif_RF value can be obtained.

[0079] Table 2 Phase Mapping Table

[0080]

[0081] Among them, PHS_dif_RF represents the phase difference between the sender and the receiver.

[0082] Therefore, in step five of this embodiment, the phase of the receiving party can be determined in combination with the phase mapping table. In addition, under the condition that the phase of the receiving party is known, the phase of the sending party can also be confirmed in combination with the phase mapping table.

[0083] Furthermore, the described radio frequency communication phase identification method based on a G3-Hybrid communication network further includes the following steps:

[0084] Step six: The router cascades to identify the phases of each multi-hop node according to its own phase and the phase differences between multi-hop nodes.

[0085] In the G3 network topology, the router's identification of the phase information of multi-hop nodes in the network is achieved through phase difference cascading. The router needs to determine the phase differences between the nodes on the path hop by hop, and finally calculate the phase of the target node. For example, as Figure 3 shown in an actual G3 topology network, assuming the router is at phase A, and nodes 1, 2, and 3 are the 1-hop, 2-hop, and 3-hop nodes of the router respectively, and the numbers on the arrows represent the calculation results of PHS_dif_RF in that direction. Then, in combination with Table 2, it can be known that the three nodes J1, J2, and J3 are at phases B, A, and C respectively.

[0086] As Figure 4 shown, it schematically shows a G3 network topology structure, where PANC is the router, and there are a total of 9 nodes numbered 1 to 9 in the network. Among them, nodes 1 and 2 are 1-hop nodes and communicate with the router through the PLC channel. Node 3 is a 2-hop node and communicates with the router through the PLC channel with node 2 as the relay node. In the G3 network topology structure of the prior art, the router can only identify the phase information of the above three nodes (nodes 1, 2, and 3), and the phase information of the remaining 6 nodes cannot be identified. However, the wireless radio frequency channel phase identification method proposed by the present invention can expand the phase identification ability of the G3 network topology structure and realize the identification of the phase information of all nodes without improving the hardware structure, providing important technical support for the further development and optimization of the power centralized meter reading communication system.

[0087] The above has described the embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. A radio frequency communication phase identification method based on a G3-Hybrid communication network, characterized in that: The following steps are involved: Step 1: When organizing a message, the sender obtains the time difference between the current moment and the last zero-crossing point, calculates the RF transmission PDC value after compensating the first time difference according to the current message length and the wireless channel data rate, and places the RF transmission PDC value as an extension field in the data packet. Then, the sender drives the wireless RF chip to complete the transmission of the message. Step 2: The receiver obtains the time difference between the current time and the last zero crossing point in the SFD link of the receiving process, determines the RF receiving PDC value based on the time difference between the current time and the last zero crossing point in the SFD link of the receiving process and passes it to the MAC layer for processing; Step 3: The receiver calculates the RF phase identification variable according to the RF receiving PDC value Rx_PDC_RF and the RF transmitting PDC value Tx_PDC_RF. The calculation formula is: PDC_dif_RF=Rx_PDC_RF-Tx_PDC_RF; Among them, PDC_dif_RF represents the RF phase identification variable, Tx_PDC_RF represents the RF transmit PDC value, and Rx_PDC_RF represents the RF receive PDC value; Step 4: Determine the phase difference between the sender and the receiver based on the RF phase identification variable; Step 5: Determine the phase of the sender or receiver based on the phase difference between the sender and the receiver.

2. The method for phase identification of radio frequency communication based on G3-Hybrid communication network according to claim 1, characterized in that: In step 1, the calculation formula of the radio frequency transmission PDC value is: Tx_PDC_RF=(zc tick +T1+T2+T3) / S; Among them, zc tick Indicates the time difference between the sender's current time and the last zero crossing point, and T1 indicates the time difference zc taken from the sender tick T2 represents the program execution time of the physical layer sending function, T3 represents the time from the completion of the sending by the sender to the SFD interruption at the receiving end, and S represents the time resolution of the unit PDC.

3. The method for phase identification of radio frequency communication based on G3-Hybrid communication network according to claim 1, characterized in that: In step 2, the calculation formula of the RF receiving PDC value is: Rx_PDC_RF=zc tick2 / S; Among them, zc tick2 It indicates the time difference between the SFD link in the receiving process of the receiver and the last zero crossing point, and S indicates the time resolution of the unit PDC.

4. The method for identifying radio frequency communication phase based on a G3-Hybrid communication network according to claim 2 or 3, characterized in that: The time resolution of a unit PDC is: S = T / 256; Wherein, T represents the industrial frequency alternating current cycle.

5. The method for phase identification of radio frequency communication based on G3-Hybrid communication network according to claim 1, characterized in that: In the step 1, when the sender organizes the message, the time difference between the current time and the last zero crossing is obtained through the internal software timer TIMER_1.

6. The method for phase identification of radio frequency communication based on G3-Hybrid communication network according to claim 1, characterized in that: In the step 2, the receiver obtains the time difference between the current time and the last zero crossing point through the internal software timer TIMER_1 in the SFD link in the receiving process.

7. The method for phase identification of radio frequency communication based on G3-Hybrid communication network according to claim 1, characterized in that: In step 4, the method for determining the phase difference between the sender and the receiver is: If the phase identification variable PDC_dif_RF belongs to the interval [0,22) or the interval [232,255], the phase difference between the sender and the receiver is 0; If the phase identification variable PDC_dif_RF belongs to the interval [22,64), the phase difference between the sender and the receiver is 1; If the phase identification variable PDC_dif_RF belongs to the interval [64,106), the phase difference between the sender and the receiver is 2; If the phase identification variable PDC_dif_RF belongs to the interval [106,148), the phase difference between the sender and the receiver is 3; If the phase identification variable PDC_dif_RF belongs to the interval [148,190), the phase difference between the sender and the receiver is 4; If the phase identification variable PDC_dif_RF belongs to the interval [190,232), the phase difference between the sender and the receiver is 5.

8. The method for radio frequency communication phase identification based on a G3-Hybrid communication network according to claim 1, characterized in that: The step 4 also includes a step of determining whether the RF phase identification variable is a negative value. If it is a negative value, the value is added with 255 as a new RF phase identification variable.

9. The method for phase identification of radio frequency communication based on G3-Hybrid communication network according to claim 1, characterized in that: In step 5, the phase of the receiver is determined in combination with a phase mapping table, and the phase mapping table is as follows: Among them, PHS_dif_RF represents the phase difference between the sender and the receiver.

10. The method for radio frequency communication phase identification based on a G3-Hybrid communication network according to claim 1, characterized in that: The following steps are also included: Step 6: The router cascades and identifies the phase of each multi-hop node based on its own phase and the phase difference between the multi-hop nodes.

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