Wireless communication method and system for passive wireless electronic transformer

Abstract

The invention discloses a passive wireless electronic transformer wireless communication method and system, and relates to the technical field of power grid current wireless passive monitoring, and the method comprises the steps: obtaining a data reading command transmitted to a transponder by an upper computer; based on the data reading command, the repeater generates a reading control instruction and transmits the reading control instruction to the reader; based on the reading control instruction, the reader transmits a radio frequency query pulse to a chip included in the reader, and the radio frequency query pulse transmits current waveform data to the reader by using backscattering modulation; and acquiring the current waveform data by using the upper computer to form passive wireless acquisition. On the basis of the microwave energy collection management circuit and the current waveform collection circuit, collected current waveforms are transmitted in a backscatter communication mode, wireless communication between the upper computer and current collection is achieved, and the current measurement system has the passive and wireless characteristics.

Description

Technical Field

[0001] The invention relates to the technical field of wireless passive monitoring of power grid current, in particular to a wireless communication method and system for a passive wireless electronic mutual inductor. Background Art

[0002] The current monitoring sensor circuit is powered by collecting microwave energy emitted by a given microwave source. However, due to the low microwave collection efficiency, the peak power is between 60% and 70%, and the microwave space attenuation is severe. Therefore, the collected electric energy is small and cannot meet the minimum energy requirements of conventional wireless communications such as WiFi, Lora, Bluetooth and Zigbee. Backscatter communication achieves the modulation of the 0 and 1 of the energy size of the RF reflected signal by changing the impedance of the antenna. During the entire communication process, only the on and off of the low-power switch control circuit is required to modulate the impedance of the antenna. Therefore, the energy consumed by backscatter communication is very small compared to traditional wireless signal transmission methods.

[0003] Unlike traditional unidirectional channels, the physical channel of backscatter communication can be modeled as a bidirectional channel with a forward sub-channel and a backscatter sub-channel, that is, the product of two unidirectional channels. According to different radio propagation environments, the two sub-channels can be regarded as specific fading channels. Although backscatter communication has become a popular communication technology in the field of Internet of Things due to its low power consumption and low complexity, in actual application scenarios, some researchers have found that backscatter channels have deeper fading than traditional active channels. This energy transmission characteristic and the channel structure of secondary fading will reduce the data reliability and operating range of backscatter communication in actual applications, resulting in signal instability and the transmission rate will also be affected. This problem has always been an important technical problem in the field of backscatter communication, especially in the indoor multipath propagation environment, the reading range and read-write accuracy of backscatter communication will be seriously affected. Therefore, how to effectively alleviate this channel attenuation and thereby improve the transmission rate and transmission distance has become a technical problem facing backscatter communication. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is how to provide a passive wireless electronic mutual inductor wireless communication method and system, based on a microwave energy collection management circuit and a current waveform acquisition circuit, to transmit the collected current waveform by means of backscatter communication, to realize wireless communication between a host computer and the current acquisition, so that the current measurement system has the characteristics of passive wireless.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In the first aspect, an embodiment of the present invention provides a passive wireless electronic transformer wireless communication method, which includes obtaining a read data command transmitted from a host computer to a repeater; based on the read data command, the repeater generates a read control instruction and transmits it to a reader; based on the read control instruction, the reader transmits a radio frequency query pulse to a chip contained in the reader, and the radio frequency query pulse utilizes backscatter modulation to transmit current waveform data to the reader; and the current waveform data is obtained by utilizing the host computer to form passive wireless acquisition.

[0008] As a preferred solution of the wireless communication method of the passive wireless electronic mutual inductor described in the present invention, wherein: the reader includes a digital baseband and interface circuit, a transmitting link, a receiving link, an interface demodulation circuit and a power supply circuit; the power supply circuit is respectively connected to the digital baseband and interface circuit, the transmitting link, the receiving link and the interface demodulation circuit; the digital baseband and interface circuit are respectively connected to the transmitting link, the receiving link and the interface demodulation circuit; the transmitting link is connected to the antenna; the receiving link is connected to the interface of the chip; the interface demodulation circuit is connected to the interface of the chip.

[0009] As a preferred solution of the passive wireless electronic transformer wireless communication method described in the present invention, wherein: the data packet format of the read control instruction includes Head, Len, Address, Cmd, Data and Check; the data packet format of the current waveform data includes Head, Len, Address, Cmd, Data and Check.

[0010] As a preferred solution of the wireless communication method of the passive wireless electronic mutual inductor described in the present invention, wherein: the repeater includes a serial port transceiver module, a control module, a TTL asynchronous serial communication module and a power module; the power module is respectively connected to the serial port transceiver module, the control module and the TTL asynchronous serial communication module; the chip of the control module adopts a controller, and one of the UART modules provided by the controller is selected to perform serial port communication with the WiFi module through the level conversion module and the serial port transceiver module, and the other UART module performs serial port communication with the reader through the TTL asynchronous serial communication module.

[0011] As a preferred solution of the passive wireless electronic transformer wireless communication method described in the present invention, wherein: a passive wireless electronic transformer wireless communication system also includes a radio frequency transmitting front end and a microwave energy acquisition module; the radio frequency transmitting front end is connected to the antenna, and is used to provide a microwave energy source for the microwave energy acquisition module, including a microwave signal generator and a Chebyshev-type low-pass filter connected to each other; the radio frequency transmitting front end performs impedance matching on the input and output of the power amplifier, and then fine-tunes the parameters.

[0012] As a preferred solution of the passive wireless electronic transformer wireless communication method described in the present invention, wherein: using the host computer to obtain the current waveform data means that the host computer processes the original signal fed back by the reader based on a greedy heuristic algorithm to obtain an approximate representation of the original signal, including the following steps: representing the original signal as a linear combination of a set of atoms, selecting atoms orthogonal to the residual in each iteration and adding them to the linear combination; constructing an optimization problem to reconstruct the signal with noise; generating an atomic index list and a weight scalar.

[0013] As a preferred solution of the passive wireless electronic transformer wireless communication method described in the present invention, the wireless communication protocol process of the electronic transformer includes: receiving data, caching data according to the receiving peripheral, establishing a parser, and the communication protocol frame structure includes a frame start character, an address field, a frame start character, a control code, a data field length, a data field, a check code and an end character; the parser first checks whether the start character, frame length, check bit and address field of the protocol frame are correct. If correct, the next step is executed, otherwise the parser is released and the process ends; by parsing the protocol header and data field information in the network data packet, different levels of protocols are identified and decoded, the protocol list is queried, and after calling the callback function, the protocol is responded to according to the peripheral type and the parser is released.

[0014] In the second aspect, in order to further solve the safety problems existing in the wireless passive monitoring of power grid current, the embodiment of the present invention provides a passive wireless electronic transformer wireless communication system, which includes: a command acquisition module, used to obtain the read data command transmitted from the host computer to the repeater; a control instruction module, used to generate a read control instruction based on the read data command and transmit it to the reader; a current waveform module, used to enable the reader to transmit a radio frequency query pulse to the chip based on the read control instruction, while the radio frequency query pulse provides radio frequency energy to the chip, uses the transmission carrier to realize tag backscattering, and returns the current waveform data to the reader through backscatter modulation; a wireless communication module is used to obtain and display the current waveform data using the host computer, so as to realize passive wireless collection of the current waveform data.

[0015] In a third aspect, an embodiment of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, any step of a passive wireless electronic mutual inductor wireless communication method as described in the first aspect of the present invention is implemented.

[0016] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, any step of a passive wireless electronic transformer wireless communication method as described in the first aspect of the present invention is implemented.

[0017] Beneficial effects of the invention: The invention proposes a passive wireless electronic mutual inductor wireless communication method and system, which is based on a microwave energy collection management circuit and a current waveform acquisition circuit. The collected current waveform is transmitted by utilizing backscatter communication to achieve wireless communication between a host computer and the current acquisition, so that the current measurement system has passive wireless characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0019] Figure 1 This is an overall flow chart of a passive wireless electronic mutual inductor wireless communication method in Example 1.

[0020] Figure 2 This is a structural block diagram of a passive wireless electronic mutual inductor wireless communication system in Example 1.

[0021] Figure 3 This is a schematic diagram of the structure of the 485 level conversion module in Example 1.

[0022] Figure 4 This is a functional block diagram of the RFID reader in Example 1.

[0023] Figure 5 This is a schematic diagram of the MCU embedded control circuit in Example 1.

[0024] Figure 6 This is a module block diagram of the RF transmission front end in Example 1.

[0025] Figure 7 Schematic diagram of the circuit structure and parameter configuration of the low-pass filter in Example 1.

[0026] Figure 8 Schematic diagram of ADS simulation results of the low-pass filter in Example 1.

[0027] Fig. 9 This is a peripheral circuit diagram of the RF6886 power amplifier in Example 1.

[0028] Fig.10 Schematic diagram of the input T-type matching network in Example 1.

[0029] Fig.11 This is the PCB layout of the reader / writer transceiver adapter module in Example 1.

[0030] Fig.12 Schematic diagram of the relationship between the frequency test success rate and sampling time of the compressed sensing method in Example 1.

[0031] Fig.13 This is the flow chart of the protocol analyzer in Example 1.

[0032] Fig.14 This is a schematic diagram of the structure of the computer device in Example 3.

[0033] Fig.15 This is a schematic diagram of the current waveform data communication test in Example 4.

[0034] Fig.16 Schematic diagram of the current waveform obtained by testing the present invention in Example 4. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0038] Example 1

[0039] Reference Figures 1 to 13 , which is the first embodiment of the present invention, and provides a passive wireless electronic mutual inductor wireless communication method.

[0040] The existing electronic mutual inductor communication methods mainly have the following problems: the existing backscatter channel has a deeper attenuation than the traditional active channel. This energy transmission characteristic and the secondary fading channel structure will reduce the data reliability and operating range of the backscatter communication in practical applications, resulting in signal instability and the transmission rate will also be affected; especially in the indoor multipath propagation environment, the reading range and reading and writing accuracy of the backscatter communication will be seriously affected.

[0041] The present application provides a method that can effectively solve the above-mentioned problems. Next, how to implement the wireless communication method of a passive wireless electronic mutual inductor will be described in detail in combination with multiple embodiments.

[0042] Figure 1 The overall flow chart of a passive wireless electronic mutual inductor wireless communication method is shown, including:

[0043] S1: Get the read data command transmitted from the host computer to the repeater.

[0044] Preferably, a passive wireless electronic mutual inductor wireless communication system comprises a plurality of RFID readers, a plurality of transponders, a WiFi module, a tag and a host computer, wherein the RFID readers and transponders correspond one to one and work in coordination.

[0045] Furthermore, the host computer transmits the read data command to the repeater through the WiFi module. After receiving the read data command, the repeater generates a read control instruction and sends it to the RFID reader. After receiving the read control instruction, the RFID reader transmits an encoded 915MHz RF query pulse to the RFID chip contained in it. The RF query pulse provides 915MHz RF energy for the RFID chip. While meeting the distance limit of the forward link, the transmitting carrier is used to realize tag backscattering, and the current waveform data is returned to the RFID reader through backscattering modulation. The repeater controls the RFID reader through commands to obtain the current waveform data, and transmits the current waveform data to the WiFi module through the serial port protocol. The host computer obtains the current waveform data in the form of WiFi and displays it, thereby realizing passive wireless collection of the current waveform.

[0046] Furthermore, the present invention transmits the collected current waveform to the RFID chip through a low-power current collection and control circuit, thereby realizing the transmission of the collected current waveform; the RFID reader side designs and manufactures a signal forwarding circuit, which controls the RFID reader on the one hand, and transmits the obtained current waveform to the host computer via WiFi and displays it on the other hand.

[0047] like Figure 2The figure shows a block diagram of a passive wireless electronic mutual inductor wireless communication system. The sensitivity of the passive tag limits the communication distance of the traditional UHFRFID system. In addition, the current chip-type RFID tag does not have frequency distinction, and this project uses a commercial high-gain antenna. Although the commercial high-gain antenna has the strongest signal near 915MHz, if there are other strong radio frequency signals in the environment, the corresponding radio frequency signal will also be received by the commercial high-gain antenna, which will cause communication problems, garbled transmission or even failure to work. In view of the problem of limited recognition distance of the UHFRFID system, the present invention proposes a long-distance passive wireless electronic mutual inductor wireless communication system with a new architecture that meets the ISO / IEC18000-6C protocol. The system consists of a host computer, an RFID reader, a transponder, an antenna and a tag; the functions and structures of the host computer and the tag are no different from those of the traditional UHFRFID system; the RFID reader of the new architecture is a custom UHFRFID reader compatible with the ISO / EC18000-6C protocol; the functions and performance of the transponder are simpler than those of the reader / writer, and it mainly provides unlimited energy and carrier for the tag at a short distance (within 5m); an RFID reader works with a transponder, and each transponder controls the RFID reader through commands to obtain current waveform data, and then the transponder sends the obtained current waveform data to the WiFi module through the serial port protocol, and finally the host computer obtains the current waveform data in the form of WiFi and displays it, realizing passive wireless acquisition of the current waveform.

[0048] Preferably, compared with the traditional RFID system, the present invention enables the host computer to send a read data command to the repeater based on the WiFi module. After receiving the command, the repeater generates a standard RFID reader read control instruction and sends it to the RFID reader. After receiving the read command, the RFID reader transmits an encoded 915MHz radio frequency query pulse to the RFID chip. The radio frequency signal can provide 915MHz radio frequency energy for the RFID chip to meet the distance limit of the forward link. At the same time, the tag backscattering is achieved by using the transmission carrier of the query pulse, thereby increasing the working distance of the entire link for the host computer. The RFID reader in the present invention reduces the intensity of the self-interference of the RFID reader by adopting a separate receiving and transmitting structure, alleviates the linearity requirements of the RFID reader receiver and the receiver desensitization caused by the self-interference noise.

[0049] Preferably, the repeater includes a 485 serial port transceiver module, a control module, a TTL asynchronous serial communication module and a power supply module.

[0050] Specifically, the power module is connected to the 485 serial port transceiver module, the control module and the TTL asynchronous serial communication module respectively, so as to provide stable and reliable working voltage for each active device in the module.

[0051] The chip of the control module adopts the F28335 controller. One of the UART modules of the F28335 controller is selected to communicate with the WiFi module via the level conversion module and the 485 serial port transceiver module. The other UART module communicates with the RFID reader via the TTL asynchronous serial communication module.

[0052] It should be noted that the use of the F28335 controller includes the following functions: the F28335 controller, namely TMS320F28335PGFA, integrates the advantages of DSP and MCU, such as the main feature of DSP, single-cycle multiplication operation, the F28335 controller can complete 32×32-bit multiplication and accumulation operations, or two 16×16-bit multiplication and accumulation operations in 1 cycle, while the same 32-bit ordinary microcontroller requires more than 4 cycles to complete; the fast interrupt response enables the F28335 controller to protect key registers and respond quickly (smaller interrupt delay) to external asynchronous events; the F28335 controller has an 8-level pipeline protection mechanism with pipeline memory access, so the F28335 controller does not require large-capacity fast memory when running at high speed; the dedicated branch jump Branch-Iook-ahead hardware reduces the reaction time of conditional instruction execution, and the conditional storage operation further improves the performance of the F28335 controller.

[0053] The F28335 controller also has many unique features, such as the ability to perform single-cycle read, modify, change, and write operations at any memory location. It not only provides high performance and efficient code programming, but also provides many other original instructions, which generally require more than 2 cycles for ordinary MCUs. The F28335 series controller can provide 150MIPS performance on 1 flash memory node, while ordinary microcontrollers and MCUs are both below 30MIPS.

[0054] The F28335 processor can use C / C++ to write software, so users can not only use high-level languages ​​to write system programs, but also use C / C++ to develop efficient mathematical algorithms, and even interface with high-level language systems such as MATLAB or LABVIEW. The F28335 series DSP has very high performance in completing tasks such as mathematical algorithms and system control.

[0055] The F2833x floating-point controller design enables designers to easily develop floating-point algorithms and seamlessly integrate them with fixed-point machines in a cost-effective manner. Compared with a fixed-point DSP or F2812 with the same main frequency, the floating-point algorithm speed is 5 to 8 times that of a fixed-point DSP or F2812.

[0056] Furthermore, since the repeater needs to complete serial communication with the WiFi module and also with the RFID reader, the two sets of UART modules provided by F28335 are selected to realize the above functions.

[0057] Further, such as Figure 3 The figure shows the structure diagram of the 485 level conversion module. Since the adapter board in the repeater communicates with the WiFi module via 485, the UART signal from the DSP cannot be directly connected to the WiFi module, and a level conversion module must be added. The 485 level conversion module selected in the present invention is ADM2587EBRWZ, which is a level conversion module designed specifically for 485.

[0058] Preferably, the present invention introduces a transponder and generates a read control instruction, so that the host computer can communicate indirectly with the RFID reader through the WiFi module, thereby maintaining compatibility with existing RFID standards without changing the hardware design of the RFID reader and the tag; the host computer can send commands through a high-level protocol, simplifying system integration; and transferring complex protocol conversion and signal processing tasks from the RFID reader to a dedicated transponder, optimizing the system architecture.

[0059] S2: Based on the read data command, the transponder generates a read control instruction and transmits it to the reader.

[0060] Preferably, the reader refers to an RFID reader, including a digital baseband and interface circuit, a 433MHz transmission link, a 915MHz receiving link, an interface demodulation circuit and a power supply circuit, such as Figure 4 The figure shows the principle block diagram of the RFID reader, in which the design of the RFID reader is aimed at reducing the system R&D cost and development difficulty as much as possible and extending the system communication distance, and requires that the module circuit itself is simple and the delay meets the ISOEC18000-6C protocol requirements.

[0061] Specifically, the power supply circuit is respectively connected to the digital baseband and interface circuit, the 433MHz transmission link, the 915MHz reception link and the interface demodulation circuit to provide the working voltage required for the work.

[0062] The digital baseband and interface circuit are respectively connected with the 433MHz transmitting link, the 915MHz receiving link and the interface demodulation circuit.

[0063] The 433 MHz transmission link is connected to the 433 MHz antenna.

[0064] The 915MHz receiving link is connected to the RX interface of the RFID chip.

[0065] The interface demodulation circuit is connected to the TX interface of the RFID chip.

[0066] Furthermore, the interface circuit is generally used to implement program configuration and burning, including UART or JTAG, or to complete the communication between the reader module and the host computer, including RS232, RS485 or USB.

[0067] Preferably, the data packet format of the read control instruction includes: Head: data packet header.

[0068] Len: The number of bytes in the data packet starting from Len, excluding Len itself.

[0069] Address: RFID reader address.

[0070] Cmd: command code.

[0071] Data: command parameters.

[0072] Check: Checksum, the checksum of all bytes except the checksum itself.

[0073] It should be noted that the reader / writer transceiver adapter module, as an auxiliary module of the reader / writer core module, mainly includes the following three functions: 1. The reader / writer core module transmits a radio frequency signal with a center frequency of 915MHz, which queries and writes RFID tags according to the ISOEC18000-6C protocol; 2. It provides the 433MHz radio frequency signal required for microwave energy acquisition to meet the microwave energy required by the microwave energy collection and management circuit; 3. It completes the signaling analysis and handshake communication process during networking.

[0074] Further, such as Figure 5 The schematic diagram of the MCU embedded control circuit is shown. In the digital baseband circuit, the Si10xx of Silicon Lab is selected in this embodiment. The chip is an MCU with wireless transceiver function, including a 25MHz 8-bit 8051 microcontroller, supporting a frequency range of: 240M~960MHz, an output power range of Si10xx: -40~13dBm, a memory of: 64kBFlash+4kBRAM, supporting multiple interfaces, including URAT, SPI and IC; the package is QFN36 (5x6mm); the clock circuit includes two external crystal oscillators, of which the 32.768kHz crystal oscillator mainly provides a clock reference for the baseband control module, and the 30MHz crystal oscillator is used as a clock reference for the wireless transceiver module; the program download part selects the C2 interface, which occupies the least number of I / O ports and can save more I / O ports for control.

[0075] Furthermore, the work of the reader is mainly to receive control instructions to complete corresponding operations. The specific instruction data packet format is defined as shown in Table 1.

[0076] Table 1 Read control instruction data packet format table of the reader

[0077]

[0078] After receiving the control command, the reader completes the corresponding query work, and then returns the data packet through the serial port in the format shown in Table 2.

[0079] Table 2 Data packet format of current waveform data

[0080]

[0081] The commonly used control instructions of the reader are shown in Table 3.

[0082] Table 3 Common control instructions for readers

[0083]

[0084] Table 3 Common control instructions for readers

[0085]

[0086] S3: Based on the read control instruction, the reader transmits a radio frequency query pulse to the chip contained in the reader, and the radio frequency query pulse uses backscatter modulation to transmit current waveform data to the reader.

[0087] Specifically, the chip is an RFID chip included in an RFID reader.

[0088] Preferably, the data packet format of the current waveform data includes: Head: data packet header.

[0089] Len: The number of bytes in the data packet starting from Len, excluding Len itself.

[0090] Address: The address of the RFID reader itself.

[0091] Cmd: command code.

[0092] Data: Data returned by the RFID reader.

[0093] Check: Checksum, the checksum of all bytes except the checksum itself.

[0094] It should be noted that a passive wireless electronic transformer wireless communication system also includes an RF transmitting front end and a microwave energy harvesting module, wherein the RF transmitting front end is connected to the antenna to provide a microwave energy source for the microwave energy harvesting module, including a microwave signal generator and a Chebyshev-type low-pass filter connected to each other; the RF transmitting front end performs impedance matching on the input and output of the power amplifier, and then fine-tunes the parameters. Impedance matching on the input and output of the power amplifier refers to matching the output impedance of the RF switch to the conjugate of the input impedance of the power amplifier, thereby achieving maximum transmission of power from source to load and no phase shift of the signal during transmission.

[0095] Specifically, Figure 6 The figure shows the module block diagram of the RF transmitting front end. The main function of the RF transmitting front end is to provide a stable microwave energy source for the microwave energy acquisition module. The selected microwave signal generator chip is Si10xx. When Si10xx transmits a 433MHz carrier, the nonlinear characteristics of the internal amplifier will produce high-order harmonics. In order to filter out the high-order harmonics, a Chebyshev low-pass filter (Low-passFilter, LPF) is connected to the Si10xx RF output end. Figure 7 shown.

[0096] Further, such as Figure 8 The figure shows the ADS simulation result of the low-pass filter. Since the filter has very small in-band insertion loss and high out-of-band attenuation suppression, the out-of-band suppression of the subharmonic and third harmonic of the carrier frequency is -45.6dB and -79.5B respectively. Therefore, the nonlinear harmonics of Si10xx can be filtered out well.

[0097] In addition, since the maximum carrier output power of Si10xx is 13dBm, the output power will be even smaller after the insertion loss of the filter and the RF switch, which does not meet the requirement of the maximum output power of 33dBm. Therefore, the signal after the RF switch needs to be amplified by a power amplifier before being output to the antenna port. In the present invention, the RF6886 power amplifier model of RFMD is selected. The parameters of the RF6886 power amplifier are shown in Table 4.

[0098] Table 4 Parameters of RF6886 power amplifier f = 433MHz

[0099] Parameter name Parameter Value Operating voltage 3.6V Maximum input power 12dBm Maximum output power 34dBm Amplifier Gain 33dB Work efficiency >50％

[0100] From Table 4 and the losses of the filter and RF switch described above, it can be seen that the RF6886 power amplifier can easily meet the output requirement of 30dBm power. The chip operating voltage of the RF6886 power amplifier is 36V. The peripheral circuits of the RF6886 power amplifier are as follows: Fig. 9 shown.

[0101] Furthermore, in the RF circuit, in order to match the impedance of the front-stage circuit with that of the rear-stage circuit and reduce the power transmission loss caused by the signal reflection caused by the mismatch, the input and output of the power amplifier are generally impedance matched, wherein the input matching is to match the output impedance of the RF switch (generally 50 ohms) to the conjugate of the input impedance of the power amplifier. In addition to maximizing the transmission of power from the source to the load, the impedance matching can also ensure that the signal has no phase shift during the transmission process; in the design process of impedance matching, the ADS simulation software can be used for the initial design, and then the parameters can be fine-tuned through actual testing. In the present invention, the input matching adopts a T-type network, and the specific structure and parameters are as follows: Fig.10 shown.

[0102] For power amplifiers, the power loss of the output matching circuit of the power amplifier is the key. These power losses exist in the inductors, capacitors and other energy-consuming components in the matching network. The power loss will reduce the efficiency and power output capacity of the power amplifier. Therefore, the inductors and capacitors of the output link are required to have high Q values ​​during the design process.

[0103] Preferably, the present invention realizes efficient use of energy and information by utilizing radio frequency query pulses, wherein the 915 MHz radio frequency pulse provides the RFID chip with the energy required for operation, solving the power supply problem of passive equipment; the 915 MHz radio frequency pulse is used as a backscattered carrier for information transmission; through carefully designed radio frequency parameters, while meeting the forward link, that is, the energy transmission distance requirement, the reverse link, that is, the reliability of data transmission is also guaranteed; this dual utilization not only improves the energy efficiency of the system, but also simplifies the hardware design and reduces interference sources. Compared with traditional methods, the present invention can achieve a longer communication distance at the same transmission power, or reduce power consumption at the same distance, which is more beneficial for battery-powered or energy collection systems.

[0104] S4: Use the host computer to obtain current waveform data to form passive wireless acquisition.

[0105] Preferably, Fig.11 The figure shows the PCB layout of the reader / writer transceiver adapter module, wherein the PCB layout design includes the frequency range of the PCB board, the PCB board layer structure and the wiring rules; firstly, as for the frequency range of the PCB board, since the dielectric constant of FR-4 (epoxy glass cloth laminate) is 4.0-4.5, it is suitable for signal layout below 2GHz, and FR-4 has excellent mechanical and electrical properties, and also has great advantages in processing technology, resulting in the wide application of FR-4, so the circuit board material of the present invention adopts FR-4 material.

[0106] Secondly, as for the PCB board layer structure, the layer structure of the PCB is generally composed of a signal layer, a power layer and a ground layer. The number of layers of the PCB board is determined by the flying wire connection after the component layout, the board size and the circuit requirements. A four-layer board structure is adopted in the design of the present invention. Considering that the RF routing requires a complete ground plane and the power amplifier heat dissipation requirements, the layers from top to bottom are the signal layer, the ground layer, the power layer and the ground layer (exposed copper).

[0107] Finally, as for the wiring rules, power integrity and signal integrity are mainly considered during wiring. The rules of thumb to ensure power integrity include: make the power layer and the ground layer adjacent layers, the dielectric between the planes is thin enough, and the plane is close to the surface layer of the power stack structure; use short and wide surface traces between the decoupling capacitor pads and the vias connected to the inner power / ground plane cavity, and place capacitors at the lowest loop position; for signal integrity, the main factors to ensure that the transmission waveform is not distorted and the signal crosstalk between the wires is small. In addition, EMC is also a key consideration.

[0108] It should be noted that according to the Shannon-Nyquist sampling theorem, when the sampling rate of commercial RFID equipment is 100Hz, it can only sense signals below 50Hz. However, in real life, the frequency of many signals exceeds 50Hz, which leads to an undersampling recovery problem, that is, how to recover high-frequency signals under a limited sampling rate. Compressed sensing (CS), as an emerging signal processing theory, breaks the limitations of the traditional Nyquist sampling theorem and achieves efficient data acquisition and processing through a small amount of random sampling and sparse signal reconstruction.

[0109] Specifically, the steps of the compressed sensing solution algorithm mainly include sparse representation and signal reconstruction, wherein sparse representation refers to the process of converting the original signal into a sparse vector, and signal reconstruction refers to restoring the original signal from the sparse representation. Usually, the compressed sensing solution algorithm is mainly divided into optimization-based methods and greedy-based methods, wherein the present invention adopts a greedy-based heuristic algorithm, the most commonly used of which is the orthogonal matching pursuit algorithm OMP.

[0110] Preferably, using the host computer to obtain the current waveform data means that the host computer processes the original signal fed back by the reader based on a greedy heuristic algorithm to obtain an approximate representation of the original signal, including the following steps: representing the original signal as a linear combination of a set of atoms, selecting atoms orthogonal to the residual in each iteration and adding them to the linear combination, and the specific formula is as follows:

[0111] st||x||0≤k

[0112] Among them, y is the original signal; φ is the atomic matrix; x is the sparse coefficient vector; k is the sparsity, that is, the number of non-zero elements in the sparse vector; the advantage of the greedy method is that the calculation speed is very fast, but the sparsity and accuracy are not as good as the optimization-based method.

[0113] An optimization problem is constructed to reconstruct a noisy signal, where the noisy signal can be reconstructed by solving the optimization problem to achieve a low signal-to-noise ratio. The specific formula is as follows:

[0114] st||S||0≤K

[0115] Among them, y is the noise signal; φ is the atomic matrix; ψ is the transformation matrix; S is the sparse coefficient vector; K is the sparsity of the sparse coefficient vector S.

[0116] The main idea of ​​the greedy heuristic algorithm is to generate an atomic index list F(S) and a weight scalar P(S) to represent the solution of sparse signal representation. The specific formula is as follows:

[0117]

[0118] Among them, F(S) is the atomic index list; P(S) is the weight scalar list; f i is the atomic index, indicating the index position of the i-th non-zero element in the sparse signal S; p i is the value of the i-th non-zero element in the sparse signal; S is the sparse coefficient vector; R i is the approximation error; τ is the number of items. In each round, the weight scalar P(S) is iteratively adjusted in a greedy manner to make the approximation error R i Minimize; y is the noise signal; φ is the atomic matrix; ψ is the transformation matrix; S i is the signal in the i-th iteration.

[0119] Further, such as Fig.12 The figure shows the relationship between the frequency test success rate and the sampling time of the compressed sensing method. It can be seen that when the sampling time T≤4.9μs, the frequency test success rate shows quasi-periodicity, and the test effect continues to improve; when the sampling time T>4.9μs, the frequency test success rate of the system exceeds 99%. Therefore, when the effective signal length of the sensor exceeds 4.9μs, the compressed sensing method can be used to process the echo signal, thereby meeting the test requirements of an effective signal length of 5 microseconds to 10 microseconds. The compressed sensing method can cope with the challenges of short echo signal length, low signal-to-noise ratio and continuous frequency changes.

[0120] Furthermore, after applying the orthogonal matching pursuit algorithm, the present invention obtains an approximate representation of the original signal, wherein the purpose of designing the compressed sensing method of the present invention is to reduce the dependence on the signal-to-noise ratio of the echo signal and to build a more optimized wireless passive electronic mutual inductor demodulation system. Therefore, when analyzing the performance indicators of the demodulation system corresponding to the compressed sensing method and other direct detection methods, the comparison is mainly made from the perspectives of hardware complexity, anti-interference ability, data volume and data processing time; since the frequency estimation accuracy is mainly determined by the frequency estimation algorithm, and the algorithm is universal for each system, it is not included in the comparison; according to the relevant indicators examined by the system, the evaluation parameters of the system (fgure of merit, FOM) are comprehensively defined, and the specific formula of the evaluation parameters is as follows:

[0121]

[0122] Among them, FOM is the evaluation parameter of the system; f s is the sampling rate; T SNR N is the signal-to-noise ratio that the system can tolerate for normal operation; M is the number of modules required, that is, the number of modules still required after removing common modules such as RF switches, LNA and BPF; T S is the processing time of a single data; the numerator in the above formula is the performance parameter of the system, and the denominator is the cost parameter required to achieve the performance; the parameters on the numerator are all taken inversely, indicating that the larger the evaluation parameter FOM of the system, the stronger the performance of the system; due to the large magnitude difference between the data and the different dimensions, this example uses the inverse tangent data preprocessing method to adjust the data distribution. The specific formula is as follows:

[0123]

[0124] Among them, data' is the preprocessing result of the data; data is the original data; N M is the number of modules required, that is, the number of modules that are still needed after removing common modules, such as RF switches, LNA, and BPF; since the number of modules required N M Since it is linear data, no preprocessing is required, which can dilute the weight of the data and focus the evaluation parameter FOM of the system on the signal-to-noise ratio T that the system can tolerate for normal operation. SNR superior.

[0125] Preferably, compared with other methods such as Nyquist sampling, Fourier transform or filtering, the compressed sensing method proposed in the present invention is not only low-cost, but also can effectively reconstruct signals under low signal-to-noise ratio conditions, and has significant advantages in cost and performance; at present, the aspects that restrict the compressed sensing method are mainly sparsity assumptions, measurement matrix design, reconstruction algorithm complexity, stability, robustness and noise. Although the compressed sensing method performs well in a low signal-to-noise ratio environment, it is still affected by noise, especially when the noise level is high, the reconstruction accuracy may decrease; therefore, compared with other methods, the compressed sensing detection method is a more ideal wireless passive electronic mutual inductance sensor signal demodulation method.

[0126] Preferably, the present invention defines the evaluation parameters of the system, takes into account multiple factors such as sampling rate, noise resistance, hardware complexity and processing time, and provides a comprehensive system evaluation index; by using the inverse tangent data preprocessing method to adjust the data distribution, the influence of the magnitude differences between different parameters is effectively reduced, making the evaluation more objective and fair.

[0127] Furthermore, since improving the wireless communication protocol of the electronic mutual inductor can significantly improve performance and reliability, and the design and improvement of the wireless communication protocol involves multiple aspects, including signal transmission reliability, data transmission rate, energy consumption management and security, the present invention selects BC26 and EC200 in the NB-IoT and Cat-1 communication modules. Both modules support multiple network communication protocols, including TCP / IP, UDP, HTTP and MQTT; in order to increase the reusability of the communication module, the present invention finally selects the MQTT protocol supported by both modules.

[0128] Specifically, Fig.13 The flowchart of the protocol parser is shown. Since the instruction system functions of the traditional client and the Web end are almost the same, in order to improve the modularity of the software, the MQTT transmission of the present invention adopts a protocol frame consistent with the 485 communication, and establishes a protocol parser.

[0129] First, since the data formats of the three communication modes 485, NB-IoT and Cat-1 are different, the received data needs to be preprocessed and cached separately. In order to save stack space, the protocol parser only opens up space for parsing when data is incoming. The entire protocol is modified based on the multi-function electric energy meter communication protocol DTL645 formulated by the State Grid Corporation of China, and a customized application layer communication protocol suitable for multi-user power consumption systems is defined. The specific structure is shown in Table 5.

[0130] Table 5 Communication protocol frame structure table

[0131] illustrate Start of Frame Address field Start of Frame Control Code Data field length Data Field Check code End Code 68H A0-A5 68H C L DATA CRA 16H byte 1 6 1 1 2 L 4 1

[0132] Specifically, the wireless communication protocol process of the electronic mutual inductor includes: receiving data, caching data according to the receiving peripheral, establishing a parser, and the communication protocol frame structure includes a frame start character, an address field, a frame start character, a control code, a data field length, a data field, a check code, and an end character.

[0133] The parser first checks whether the start character, frame length, check bit and address field of the protocol frame are correct. If correct, it executes the next step. Otherwise, it releases the parser and ends the process. The parser first checks the start character and end character of the protocol frame to preliminarily confirm the correctness and completeness of the protocol as quickly as possible, while improving the parsing efficiency.

[0134] The protocol parser identifies and decodes protocols at different levels by parsing the protocol header and data field information in the network data packet. During the development process, the protocol parser can capture and analyze network data packets, diagnose network faults, discover and solve network bottlenecks, thereby improving network reliability and performance, query the protocol list, call the callback function, respond to the protocol according to the peripheral type, and release the parser.

[0135] Preferably, the present invention ensures the compatibility of the system with a variety of IoT devices and platforms by adopting the MQTT protocol and the wireless communication protocol. At the same time, the lightweight characteristics of the MQTT protocol are more suitable for resource-constrained passive devices. Secondly, the wireless communication protocol is modified based on DTL645 to ensure the reliability and security of the wireless communication protocol in the power system, and the data processing efficiency is improved by adopting a protocol parser.

[0136] In summary, the present invention proposes a passive wireless electronic mutual inductor wireless communication method and system, which is based on a microwave energy collection management circuit and a current waveform acquisition circuit. The collected current waveform is transmitted by utilizing backscatter communication to realize wireless communication between a host computer and the current acquisition, so that the current measurement system has the characteristics of passive wireless.

[0137] Embodiment 2 is an embodiment of the present invention, which provides a passive wireless electronic transformer wireless communication system, including: a command acquisition module, used to obtain the read data command transmitted from the host computer to the repeater; a control instruction module, used to generate a read control instruction based on the read data command and transmit it to the reader; a current waveform module, used to enable the reader to transmit a radio frequency query pulse to the chip based on the read control instruction, while the radio frequency query pulse provides radio frequency energy to the chip, uses the transmission carrier to realize tag backscattering, and returns the current waveform data to the reader through backscattering modulation; a wireless communication module, used to use the host computer to obtain the current waveform data and display it, so as to realize passive wireless collection of the current waveform data.

[0138] Embodiment 3 is an embodiment of the present invention, which is different from the previous embodiment in that:

[0139] like Fig.14 As shown, if the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, 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, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0140] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0141] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0142] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0143] Embodiment 4 is an embodiment of the present invention, which provides a passive wireless electronic mutual inductor wireless communication method. In order to verify the beneficial effects of the present invention, a scientific demonstration is carried out through simulation experiments.

[0144] This example simulates the wireless communication experiment of the sensor tag circuit. The circuit debugging of the long-distance RFID includes the debugging of the power supply circuit, baseband control and interface circuit, RF transmission circuit and RF receiving circuit of the reader / writer adapter module and the transponder respectively. The basic method of step-by-step welding and step-by-step debugging is followed during the debugging process.

[0145] In order to test the designed low-power wireless communication system, a current waveform test and communication system was built, such as Fig.15 The figure shows a schematic diagram of current waveform data communication test, in which the red cable is for passing unidirectional alternating current signals. When the designed current sensor tag is placed near the cable, the tag is powered by the designed microwave energy extraction circuit; the microwave energy extraction signal source provides stable microwaves for the module designed on the repeater circuit in the present invention, and the emitted microwave power is 30dBm and the frequency is 433MHz; commercial WiFi communication is adopted between the host computer and the repeater, and 485 communication is adopted between the WiFi module and the DSP; the host computer sends the query command in the form of query, the repeater receives the query command and parses it, and then converts it into a standard RFID reader instruction and sends it to the RFID reader through the serial port; after receiving the instruction, the RFID reader sends a response command, reads the current waveform data and forwards it to the repeater, and the repeater sends it to the host computer through the WiFi module and finally completes the display.

[0146] According to the above working process, the current waveform data communication was tested. The current waveform obtained by the test is as follows: Fig.16As shown in the figure, it can be seen that the wireless communication method designed by the present invention can realize the transmission of the current waveform, and there is no packet loss, bit error or mismodulation in the current waveform transmission, indicating that the wireless communication scheme designed by the present invention can be used for the low-power wireless communication requirements of the passive wireless tag current transformer circuit, and can complete the wireless transmission of the current waveform, laying the foundation for the smooth completion of the overall task of the present invention.

[0147] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A passive wireless electronic transformer wireless communication method, characterized in that: include: Get the read data command transmitted from the host computer to the transponder; Based on the read data command, the transponder generates a read control instruction and transmits it to the reader; Based on the read control instruction, the reader transmits a radio frequency inquiry pulse to a chip included in the reader, the radio frequency inquiry pulse transmitting current waveform data to the reader using backscatter modulation; The host computer is used to acquire the current waveform data to form passive wireless acquisition.

2. The passive wireless electronic transformer wireless communication method according to claim 1, characterized in that: The reader includes a digital baseband and interface circuit, a transmission link, a receiving link, an interface demodulation circuit and a power supply circuit; The power supply circuit is respectively connected to the digital baseband and interface circuit, the transmission link, the receiving link and the interface demodulation circuit; The digital baseband and interface circuit are respectively connected to the transmission link, the receiving link and the interface demodulation circuit; The transmission link is connected to the antenna; The receiving link is connected to the interface of the chip; The interface demodulation circuit is connected to the interface of the chip.

3. The passive wireless electronic transformer wireless communication method according to claim 2, characterized in that: The data packet format of the read control instruction includes Head, Len, Address, Cmd, Data and Check; The data packet format of the current waveform data includes Head, Len, Address, Cmd, Data and Check.

4. The passive wireless electronic transformer wireless communication method according to claim 3, characterized in that: The repeater includes a serial port transceiver module, a control module, a TTL asynchronous serial communication module and a power supply module; The power supply module is connected to the serial port transceiver module, the control module and the TTL asynchronous serial communication module respectively; The chip of the control module adopts a controller, and one of the UART modules of the controller is selected to communicate with the WiFi module via the level conversion module and the serial port transceiver module, and the other UART module communicates with the reader via the TTL asynchronous serial communication module.

5. The passive wireless electronic transformer wireless communication method according to claim 4, characterized in that: A passive wireless electronic mutual inductor wireless communication system also includes a radio frequency transmission front end and a microwave energy acquisition module; The radio frequency transmitting front end is connected to the antenna and is used to provide a microwave energy source for the microwave energy acquisition module, including a microwave signal generator and a Chebyshev type low-pass filter connected to each other; The RF transmission front end performs impedance matching on the input and output of the power amplifier, thereby fine-tuning the parameters.

6. The passive wireless electronic transformer wireless communication method according to claim 5, characterized in that: Using the host computer to obtain the current waveform data means that the host computer processes the original signal fed back by the reader based on a greedy heuristic algorithm to obtain an approximate representation of the original signal, including the following steps: The original signal is represented as a linear combination of a set of atoms, and in each iteration, atoms orthogonal to the residual are selected and added to the linear combination; Formulate optimization problems to reconstruct noisy signals; Generate a list of atom indices and weight scalars.

7. The passive wireless electronic transformer wireless communication method according to claim 6, characterized in that: The wireless communication protocol process of the electronic transformer includes: Receive data, cache data according to the receiving peripheral, establish a parser, and the communication protocol frame structure includes a frame start character, an address field, a frame start character, a control code, a data field length, a data field, a check code, and a terminator; The parser first checks whether the start character, frame length, check bit and address field of the protocol frame are correct. If they are correct, the next step is executed. Otherwise, the parser is released and the process ends. By parsing the protocol header and data field information in the network data packet, identifying and decoding different levels of protocols, querying the protocol list, calling the callback function, responding to the protocol according to the peripheral type, and releasing the parser.

8. A passive wireless electronic transformer wireless communication system, based on a passive wireless electronic transformer wireless communication method according to any one of claims 1 to 7, characterized in that: include, A command acquisition module is used to acquire the data read command transmitted from the host computer to the transponder; A control instruction module, used for the transponder to generate a read control instruction based on the read data command and transmit it to the reader; The current waveform module is used to transmit a radio frequency query pulse from the reader to the chip based on the read control instruction. The radio frequency query pulse provides radio frequency energy to the chip and realizes tag backscattering by transmitting a carrier wave. The current waveform data is returned to the reader through backscattering modulation. The wireless communication module is used to obtain and display the current waveform data using the host computer, thereby realizing passive wireless collection of the current waveform data.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the passive wireless electronic mutual inductor wireless communication method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a passive wireless electronic mutual inductor wireless communication method according to any one of claims 1 to 7 are implemented.

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