CN114726395B - Wireless information and energy simultaneous transmission system based on adjustable frequency source and working method thereof - Google Patents

Abstract

The invention discloses a wireless information and energy simultaneous transmission system based on an adjustable frequency source, which comprises an adjustable frequency source, a power amplifying circuit, a power distributor, a rectifying circuit, a filtering circuit, an information demodulating circuit and a load, wherein the adjustable frequency source is connected with the power amplifying circuit, the power amplifying circuit transmits signals and energy to a receiving antenna in the form of electromagnetic waves through a transmitting antenna, the receiving antenna receives the signals and the energy transmitted by a transmitting end, the receiving antenna is connected with the power distributor, the power distributor is respectively connected with the rectifying circuit and the information demodulating circuit, the rectifying circuit is connected with the filtering circuit, and the filtering circuit is connected with the load. The invention adopts microwave type wireless communication energy transmission, and does not adopt a switch to switch signals, compared with the prior art, the invention has the advantages of strong flexibility, less system loss, prolonged service life, strong anti-interference performance, strong use value and wide popularization and application.

Description

Wireless Signal Energy Simultaneous Interpretation System Based on Adjustable Frequency Source and Its Working Method

technical field

The invention relates to the field of wireless technology, in particular to a wireless signal energy simultaneous interpretation system based on an adjustable frequency source and a working method thereof.

Background technique

Traditional power transmission relies on wire transmission, that is, wired power transmission, which is currently the most widely used form of power transmission. However, with the advancement of science and technology and the improvement of human living standards, the shortcomings of wired power transmission cannot be ignored: the use of a large number of wires makes human life appear chaotic; frequent plugging and unplugging of power sockets, and the wearability of wire materials And other factors have brought many potential safety hazards; the use of wires has restricted the application of electric energy. Therefore, wireless energy transfer has been greatly developed in recent years.

However, in many applications, it is not only necessary to realize the wireless transmission of energy, but also to realize the wireless transmission of information, that is, to realize the synchronous transmission of wireless energy and information. For example, in the fields of smart munitions, human implanted devices, sensor networks, RFID, mobile devices, etc., while transmitting energy, the transmitter also needs to perform two-way data transmission with the receiver, such as sending control commands from the transmitter to the receiver, and The receiver transmits sensor data, user ID, charging status, number of users, received power and other information back to the transmitter. Therefore, it is very necessary to study the synchronous transmission technology of wireless energy and information.

There are mainly two types of existing wireless signal energy simultaneous transmission methods, one is the separate channel transmission of signal and energy, and the other is the same channel transmission of signal and energy.

(1) Signal and energy channel transmission

Signal and energy sub-channel transmission uses two different sets of coils and drive circuits to perform independent energy transmission and signal transmission, as shown in Figure 1.

This method of simultaneous signal and energy transmission can be transmitted through their own channels, which has the advantages of high efficiency and fast speed. However, in the same device, because the two sets of coupling coils are too close to each other, they will interfere with each other, especially for high-power energy transmission. It is easy to cause great interference to signal transmission, thereby affecting system transmission characteristics.

(2) Signal and energy are transmitted in the same channel

The transmission of signals and energy in the same channel is generally divided into three types: simultaneous transmission of AM modulated signals, simultaneous transmission of FM modulated signals, simultaneous transmission of direct FM modulated signals, and simultaneous transmission of signal reverse signals.

a. Simultaneous interpretation based on AM modulation

This simultaneous interpretation method is to add a switch tube to the main circuit, and control the power input through the closing and opening of the switch tube, so that the amplitude of the electric energy transmission changes, so that the amplitude of the electric energy received at the output end has a digital signal "" 1", "0" features. The receiving end demodulates the signal of the transmitting end according to this change of electric energy.

b. Simultaneous interpretation based on FM modulation signal

The signal energy simultaneous interpretation technology based on FM modulation is to control the frequency of the pulse signal generated by the signal generator in the inverter circuit through soft switching technology. In the experiment, two pulse signals with different frequencies are usually set on the switch tube of the inverter circuit. , represent the digital signals "0" and "1" respectively, and the voltage waveform showing the characteristics of 010101 will be obtained on the load of the receiving end of the system, that is, the simultaneous transmission of signals and energy is completed. The circuit structure of the system is shown in Figure 2.

c. Simultaneous interpretation of signals modulated by direct FM

This method is to add a set of signal sending coils and a set of signal receiving coils without changing the structure of the inductive power transmission system. These two sets of coupling coils are similar to coupling transformers, and use the signal sending coils to directly load high-frequency signals. into the power transmitting circuit, and then the signal receiving coil picks up the signal from the power receiving circuit, and the positive signal is obtained through the demodulation circuit. Circuit diagram shown in Figure 3.

d. Signal reverse transmission

The reverse transmission of the signal is to make changes in the receiving circuit. Two capacitors are added to the receiving end, one is a resonant capacitor and the other is a detuning capacitor. The electrical energy makes it characteristic of a digital signal, which is then acquired and demodulated.

The signal energy simultaneous transmission technology based on AM modulation can accurately transmit the signal to the receiving end by controlling the on-off of the encoding switch, which has the advantages of clear 0 and 1 signal transmission boundaries, and the signal transmission is less affected by power transmission, but the invention is the most important The disadvantage is that the stability of power transmission drops significantly, and harmonic interference is easily generated at the moment of switch opening and closing, which causes a serious drop in load power during the opening period, thereby affecting transmission; based on FM modulation signal energy simultaneous interpretation technology changes the frequency of the signal Therefore, compared with AM modulation, there will be no sudden interruption and restart of energy transmission, but the efficiency of power transmission will still be reduced, and the system modulation delay will affect the signal transmission rate; the signal energy simultaneous transmission of direct FM modulation Limited to the size of the equipment, it is not suitable for equipment with a small space, and the power transmission will cause great interference to the signal coupling during the transmission process; the signal reverse transmission technology will easily cause the resonance state of the system to shift, and when the system transmission power When it is large, it will cause strong electromagnetic interference and affect the surrounding environment.

It can be seen that although the above methods can realize synchronous wireless transmission of signals and energy, each method has its own advantages and disadvantages. Therefore, it is necessary to design a signal energy system that can overcome discontinuous power supply and avoid system offset frequency. Simultaneous interpretation system. In addition, the above-mentioned methods all use magnetic coupling wireless transmission. Although this method has high transmission efficiency and good penetration, it has low transmission power and is not suitable for long-distance transmission. The design of the present invention has been carried out for the above problems.

Contents of the invention

The purpose of the present invention is to provide a wireless signal energy simultaneous transmission system based on an adjustable frequency source and its working method to solve practical technical problems such as low transmission power and unsuitability for long-distance transmission of the existing system.

The technical invention that the present invention solves the problems of the technologies described above is as follows:

A wireless signal energy simultaneous transmission system based on an adjustable frequency source, including an adjustable frequency source, a power amplifier circuit, a power divider, a rectifier circuit, a filter circuit, an information demodulation circuit, and a load. The adjustable frequency source and power The amplifying circuit is connected, and the power amplifying circuit transmits the signal and energy to the receiving antenna in the form of electromagnetic waves through the transmitting antenna, and the receiving antenna receives the signal and energy transmitted by the transmitting end, and the receiving antenna is connected to the power divider. The power divider is respectively connected with the rectification circuit and the information demodulation circuit, the rectification circuit is connected with the filter circuit, and the filter circuit is connected with the load.

Further, the adjustable frequency source is an adjustable microwave frequency source, which can control the duration of different frequencies to realize 2FSK modulation.

Further, the power amplifying circuit includes transistors.

Further, the power divider is a power splitter or a coupler.

Further, the rectification circuit is composed of rectification diodes.

Further, the filter circuit can remove fundamental frequency components and higher harmonic components.

Furthermore, the information demodulation circuit can restore the signal at the transmitting end to obtain the required digital information.

The present invention also provides a working method of a wireless signal energy simultaneous interpretation system based on an adjustable frequency source, including the following steps:

(1) Transmitter:

1) The crystal oscillator generates a reference signal s1 with a frequency f1;

2) The signal s1 is divided into two signals s2 and s3 through the power divider. The frequency of s2 and s3 is f1, and the power is divided into two parts according to a certain ratio. Among them, the signal s2 is used as the reference source of the frequency multiplication link , the signal s3 is used as the reference source of the phase-locked loop or DDS;

3) The signal s2 is amplified by the amplifier, and then the signal s4 with frequency f2 is obtained through the frequency multiplier, and the signal s4 is filtered through the filter to filter out the interference signals such as high-order harmonics and intermodulation signals generated by the frequency multiplier to obtain the frequency is the signal s5 of f2;

4) The signal s3 is input into the phase-locked loop or DDS, and the phase-locked loop or DDS is controlled by an FPGA or a single-chip microcomputer to generate a signal s6 with adjustable frequency and adjustable frequency duration. Here, it is assumed that the frequency of any adjustable signal s6 is f3;

5) The signal s5 is sent to the mixer after being amplified by the amplifier, and mixed with the signal s6 to generate a signal s7 with a frequency of f3+f2;

6) After the signal s7 passes through the filter to filter out some spurious signals generated by the mixer, the output frequency is the signal s8 of f3+f2;

7) The power of the signal s8 is amplified by the power amplifier to obtain a signal s9 with an output frequency of f3+f2, and then the signal is transmitted by the antenna;

(2) Receiver:

1) After the antenna receives the signal s9, it passes through the power divider and divides the signal into two signals, s10 and s11;

2) s10 is input into the rectifier circuit, the received AC power is converted into DC, and then the fundamental frequency component and high-order harmonic component are filtered out by the filter and then delivered to the load;

3) s11 is input into the information demodulation circuit, and the corresponding information can be demodulated.

The present invention has the following beneficial effects:

The present invention adopts microwave wireless signal energy transmission, and does not use switches to switch signals. Compared with the prior art, it not only has strong flexibility, can reduce system loss, improve service life, and has strong anti-interference performance, which highlights A significant advance in the technology of the present invention.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Figure 1 is a schematic diagram of energy and signal sub-channel transmission;

Fig. 2 is a circuit diagram of a simultaneous interpretation system based on FM modulation signal energy;

Figure 3 is a direct modulation signal energy simultaneous interpretation system;

Fig. 4 is a 2FSK signal waveform diagram;

Fig. 5 is a block diagram of a wireless signal energy simultaneous interpretation system based on an adjustable frequency source;

Fig. 6 is the specific scheme block diagram of information demodulation circuit;

Fig. 7 is a specific scheme block diagram of the adjustable frequency source.

Detailed ways

The principles and features of the present invention will be described below in conjunction with the embodiments and accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

One, technical principle of the present invention

The present invention adopts 2FSK modulation, which is a kind of FM modulation, which uses the frequency of the carrier to transmit digital information (baseband signal), that is, uses the transmitted digital information to control the frequency of the carrier. The symbol "0" represents the carrier frequency f2, and the symbol "1" represents the carrier frequency f1 (f1 and f2 are different frequencies). When the system transmits a signal "0", it sends a carrier with frequency f2; when it transmits a signal "1", it sends a carrier with frequency f1. 2FSK waveform diagram is shown in Fig. 4.

The present invention utilizes FPGA or single-chip software programming to control the phase-locked loop or DDS to keep different frequencies at different times (2FSK signal), assuming that the symbol "1" represents the frequency f1, and the symbol "0" represents the frequency f2, and the duration of one symbol The time is t1 (can be regarded as 100us in Fig. 4). Then the adjustable frequency source outputs the frequency f1 with a holding time of 2t1, and then outputs the frequency f2 with a holding time of t1, which means that the baseband signal (ie digital information) is 110.

The present invention utilizes an adjustable frequency source to output 2FSK signals, and the receiving end divides the signal power into two parts after receiving the signal, and one part can obtain the information (that is, the baseband signal) transmitted by the transmitting end through a demodulation circuit.

Two, each module description of the system of the present invention

The wireless signal energy simultaneous interpretation system based on the adjustable frequency source of the present invention, as shown in Figure 5, includes the following parts, and the description of each part is as follows:

(1) Adjustable frequency source: It is an adjustable microwave frequency source. This module can realize the output of any frequency, and can control the duration of different frequencies to realize 2FSK modulation.

(2) Power amplification circuit: It realizes the amplification of signal power, mainly composed of transistors.

(3) Power divider: It can keep the frequency of the signal unchanged, and distribute the power according to a certain ratio. It is generally realized by a power divider or a coupler, which are usually designed using microstrip lines.

(4) Rectifier circuit: A circuit that converts received AC power into DC, generally composed of rectifier diodes.

(5) Filter circuit: The rectifier circuit is realized by a rectifier diode. The nonlinear characteristics of the diode will generate high-order harmonic components, resulting in a large DC voltage pulsation component at the load end. The filter circuit is used to remove the fundamental frequency component and high-order harmonic components. Harmonic components.

(6) Information demodulation circuit: realize the restoration of the signal at the transmitting end, and obtain the required digital information.

Information demodulation circuit:

The working principle is shown in Figure 6. The frequency of the signal s9 entering the information demodulation circuit is f3+f2. Since the frequency f3 is adjustable, the frequency of the signal entering the information demodulation circuit is variable. Assuming that two signals with different frequencies are f4 and f5, when the signal of frequency f4 is input into the circuit, the f4 LC parallel resonant circuit resonates, and the f5 LC parallel resonant circuit does not resonate, and the voltage of the resonant circuit is greater than that of the non-resonant circuit Voltage, at this time the voltage comparator outputs a high level "1"; similarly, when a signal with a frequency of f5 is input, it outputs a low level "0", that is, the demodulation of the 2FSK signal is completed.

As shown in Figure 6, the description of each module is as follows:

(1) f4 LC parallel resonant circuit: a resonant circuit composed of inductors and capacitors, the resonant frequency is f4, and the signal with frequency f4 can pass through smoothly.

(2) f5 LC parallel resonant circuit: same as f4 LC parallel resonant circuit.

(3) Voltage comparator: It is used to compare the magnitude of two input voltages and is composed of operational amplifiers. When the voltage of the "+" input terminal is higher than the "-" input terminal, the output of the voltage comparator is high level, which can be expressed as a digital "1"; when the voltage of the "+" input terminal is lower than the "-" input terminal, the voltage The output of the comparator is low level, which can be represented as "0".

Three, the detailed description of the working method of the system of the present invention

In conjunction with Fig. 5, accompanying drawing 6 and accompanying drawing 7, the working method of the whole system is described:

(1) Transmitter:

1) The crystal oscillator generates a reference signal s1 with a frequency f1;

2) The signal s1 is divided into two signals s2 and s3 through the power divider. The frequency of s2 and s3 is f1, and the power is divided into two parts according to a certain ratio. Among them, the signal s2 is used as the reference source of the frequency multiplication link , the signal s3 is used as the reference source of the phase-locked loop or DDS;

3) The signal s2 is amplified by the amplifier, and then the signal s4 with frequency f2 is obtained through the frequency multiplier, and the signal s4 is filtered through the filter to filter out the interference signals such as high-order harmonics and intermodulation signals generated by the frequency multiplier to obtain the frequency is the signal s5 of f2;

4) The signal s3 is input into the phase-locked loop or DDS, and the phase-locked loop or DDS is controlled by an FPGA or a single-chip microcomputer to generate a signal s6 with adjustable frequency and adjustable frequency duration. Here, it is assumed that the frequency of any adjustable signal s6 is f3;

5) The signal s5 is sent to the mixer after being amplified by the amplifier, and mixed with the signal s6 to generate a signal s7 with a frequency of f3+f2;

6) After the signal s7 passes through the filter to filter out some spurious signals generated by the mixer, the output frequency is the signal s8 of f3+f2;

7) The power of the signal s8 is amplified by the power amplifier to obtain a signal s9 with an output frequency of f3+f2, and then the signal is transmitted by the antenna;

(2) Receiver:

1) After the antenna receives the signal s9, it passes through the power divider and divides the signal into two signals, s10 and s11;

2) s10 is input into the rectifier circuit, the received AC power is converted into DC, and then the fundamental frequency component and high-order harmonic component are filtered out by the filter and then delivered to the load;

3) s11 is input into the information demodulation circuit, and the corresponding information can be demodulated.

The system of the present invention adopts microwave wireless signal energy transmission, and does not use switches to switch signals. Compared with the prior art, it has the following technical advantages:

(1) Strong flexibility, you only need to change the code of FPGA or DDS, and you can transmit different signals without switching switches;

(2) Medium and long-distance signal transmission can be realized by using microwave transmission;

(3) Reduce system loss and improve service life. Its prior art utilizes switch switching, and requires high performance for the switch, and if continuous signals are to be transmitted, the switch needs to be switched continuously, which requires high performance for the switch, and is prone to switch loss. The present invention directly uses software control, so it does not Such problems exist;

(4) Strong anti-interference. The 2FSK modulation is used to transmit the signal without relying on the amplitude, so even if there is an interference source of the same frequency that disturbs the amplitude of the radio wave, it will not cause noise to the 2FSK signal.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (7)

1. The working method of the wireless information and energy simultaneous transmission system based on the adjustable frequency source is characterized in that the wireless information and energy simultaneous transmission system based on the adjustable frequency source comprises an adjustable frequency source, a power amplification circuit, a power divider, a rectification circuit, a filter circuit, an information demodulation circuit and a load, wherein the adjustable frequency source is connected with the power amplification circuit, the power amplification circuit transmits signals and energy to a receiving antenna in an electromagnetic wave form through a transmitting antenna, the receiving antenna receives the signals and the energy transmitted by a transmitting end, the receiving antenna is connected with the power divider, the power divider is respectively connected with the rectification circuit and the information demodulation circuit, the rectification circuit is connected with the filter circuit, and the filter circuit is connected with the load;

the working method of the wireless information and energy simultaneous transmission system based on the adjustable frequency source comprises the following steps:

(1) A transmitting end:

1) A crystal oscillator generates a reference signal s1 with frequency f 1;

2) A signal s1 is divided into two paths of signals s2 and s3 by a power divider, the frequencies of s2 and s3 are both f1, and the power is divided into two parts according to a certain proportion, wherein the signal s2 is used as a reference source of a frequency multiplication link, and the signal s3 is used as a reference source of a phase-locked loop or a DDS;

3) Amplifying the power of the signal s2 by an amplifier, then obtaining a signal s4 with the frequency f2 by a frequency multiplier, filtering out interference signals such as higher harmonics, intermodulation signals and the like generated by the frequency multiplier by the signal s4 through a filter, and obtaining a signal s5 with the frequency f 2;

4) Inputting a signal s3 into a phase-locked loop or a DDS, controlling the phase-locked loop or the DDS by using an FPGA (field programmable gate array) or a singlechip to generate a signal s6 with adjustable frequency and adjustable frequency duration, wherein the frequency of any adjustable signal s6 is assumed to be f3;

5) The signal s5 is sent to a mixer after being amplified by the amplifier, and is mixed with the signal s6 to generate a signal s7 with the frequency of f3+ f 2;

6) The signal s7 is filtered by a filter to remove some spurious signals generated by the mixer, and then a signal s8 with the frequency of f3+ f2 is output;

7) Amplifying the power of the signal s8 through a power amplifier to obtain a signal s9 with the output frequency of f3+ f2, and transmitting the signal through an antenna;

(2) Receiving end:

1) After receiving a signal s9, an antenna divides the signal into two paths of signals s10 and s11 through a power divider;

2) s10, inputting the alternating current power into a rectifying circuit, converting the received alternating current power into direct current, filtering out fundamental frequency components and higher harmonic components through a filter, and then transmitting the direct current to a load;

3) s11 is input to the information demodulation circuit, and the corresponding information can be demodulated.

2. The method of claim 1, wherein the adjustable frequency source is capable of controlling the duration of different frequencies to achieve 2FSK modulation.

3. The method of claim 1, wherein the power amplifier circuit comprises a transistor.

4. The method of claim 1, wherein the power divider is a power divider or a coupler.

5. The method as claimed in claim 1, wherein the rectifying circuit comprises a rectifying diode.

6. The method as claimed in claim 1, wherein the filtering circuit is capable of removing fundamental frequency components and higher harmonic components.

7. The method as claimed in claim 1, wherein the information demodulation circuit is capable of recovering the signal at the transmitting end to obtain the required digital information.

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