A microwave signal transmission system based on frequency modulation and amplitude modulation

Abstract

The application discloses a microwave signal and energy co-transmission system based on frequency modulation and amplitude modulation, and belongs to the technical field of electric communication. The microwave signal and energy co-transmission system comprises a microwave signal source, a frequency modulator, a power amplifier, an amplitude modulation transformer, a transceiving antenna, a directional coupler, a frequency demodulator, a rectifier circuit, a maximum power point tracking module, a load and a control unit. The frequency modulator and the frequency demodulator are jointly matched to realize information loading and analysis without affecting energy transmission. The maximum power point tracking module adopts a Boost circuit and a maximum power point tracking algorithm to realize power / efficiency improvement of the rectifier circuit at the receiving end. The amplitude modulation transformer adopts a Buck circuit to supply power for the power amplifier, the control unit acquires input voltage and input current of the amplitude modulation transformer as well as load voltage and load current, executes a maximum efficiency point tracking algorithm, and dynamically adjusts output voltage of the amplitude modulation transformer, so that the system stably works at a maximum efficiency point.

Description

Technical Field

[0001] The invention discloses a microwave signal and energy transmission system based on frequency modulation and demodulation and amplitude modulation, belonging to the field of electrical communication technology. Background Technology

[0002] Microwave simultaneous information and energy transmission technology is a technology that uses electromagnetic waves to transmit information and energy simultaneously, combining wireless information and wireless energy transmission. With the development of technology, it is expected that microwave simultaneous information and energy transmission technology can transmit energy while exchanging information, avoiding equipment failure during transmission, effectively improving equipment lifespan, and solving the problems of size and cost of wired power supply devices for each device terminal during information transmission.

[0003] Traditional microwave signal-energy simultaneous transmission technology can be achieved in two main ways: First, information transmission and energy transmission are implemented using separate channels. The information transmission channel loads, transmits, and receives information, while the energy transmission channel amplifies, transmits, and receives energy. Second, information transmission / reception and energy transmission / reception are implemented using separate channels, such as with dual-frequency antennas, while information loading and energy amplification share the same channel. While the first method allows independent control of information and energy transmission, its circuit structure is complex, transmission interference is significant, and implementation costs are high. The second method presents greater challenges in antenna design, resulting in complex structures and difficulties in meeting transmit-receive isolation requirements. The efficiency of a microwave energy transmission system is affected by both transmission power and the load at the receiver. Currently, research on improving the efficiency of microwave energy transmission systems mainly considers either transmission power or receiver load alone. Improving system efficiency from the perspective of receiver load, while ensuring the rectifier circuit always operates at its optimal load state through a maximum power point tracking module, fails to address the issue of system-level efficiency optimization. Improving system efficiency from the perspective of transmission power, while achieving system-level efficiency optimization of the microwave power transmission system through amplitude modulation and reducing system complexity by omitting the multi-stage converter between the receiver microwave rectifier circuit and the load, thus improving system-level efficiency, does not consider the impact of receiver load on efficiency, resulting in incomplete system-level efficiency optimization.

[0004] In summary, the present invention aims to propose a microwave signal-power simultaneous transmission system, and simultaneously considers the optimal system efficiency by balancing transmission power and load, in order to overcome the aforementioned shortcomings. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the aforementioned background technology by proposing a microwave signal-energy simultaneous transmission system based on frequency modulation and demodulation and amplitude modulation. By deploying a frequency modulation module and a frequency demodulation module at the transmitting and receiving ends of the microwave wireless power transmission system, respectively, information loading and parsing are achieved. By deploying a maximum power point tracking module before the load at the receiving end, efficient operation of the rectifier circuit is achieved. Furthermore, by deploying an amplitude modulation converter at the power amplifier's power supply end, system efficiency is further optimized under optimal load. This solves the technical problems of complex architecture and incomplete efficiency optimization in existing microwave signal-energy simultaneous transmission systems, achieving the invention's objective of integrating information transmission and energy transfer while simultaneously improving the efficiency of the energy transmission system.

[0006] To achieve the above-mentioned objectives, the present invention employs the following technical solution:

[0007] A microwave signal-powered simultaneous transmission system based on frequency modulation and demodulation and amplitude modulation includes: a microwave signal source, a DC power supply, a frequency modulator, a power amplifier, an amplitude modulation converter, a transmitting antenna, a receiving antenna, a directional coupler, a frequency demodulator, a rectifier circuit, a maximum power point tracking module, and a control unit; the microwave signal source is used to generate microwave signals; the DC power supply is used to generate DC power; the frequency modulator is used to load information into the microwave signal; the power amplifier amplifies the microwave signal after the information is loaded by the frequency modulator and outputs a microwave power signal; the amplitude modulation converter receives the amplitude modulation converter control signal and provides an amplitude-adjustable supply voltage to the power amplifier under the excitation of the DC power supply; and the transmitting antenna is used to transmit power. The amplifier outputs a microwave power signal; a receiving antenna receives microwave power signals radiated in space; a directional coupler couples the received microwave power signal proportionally to the frequency demodulator and rectifier circuits; the frequency demodulator demodulates the received microwave power signal; the rectifier circuit converts the received microwave power signal into electrical power; a maximum power point tracking module supplies the rectifier circuit with electrical power to the load while ensuring the rectifier circuit operates at its maximum power point regardless of load changes; and a control unit generates amplitude modulation converter control signals based on the input voltage and current of the amplitude modulation converter, as well as the load voltage and current, while maximizing system-level efficiency.

[0008] As a further optimization scheme for microwave signal and energy transmission systems based on frequency modulation and demodulation and amplitude modulation, the frequency modulator loads information into the microwave signal through Gaussian frequency shift keying modulation.

[0009] As a further optimization scheme for microwave signal and energy transmission systems based on frequency modulation and demodulation and amplitude modulation, Gaussian frequency shift keying modulation first performs Gaussian filtering on the microwave signal, and then performs frequency shift keying modulation on the filtered microwave signal. Frequency shift keying modulation can be achieved through two modulation methods: direct modulation or quadrature modulation.

[0010] As a further optimization scheme for microwave signal and power transmission systems based on frequency modulation and amplitude modulation, the frequency demodulator demodulates the received microwave power signal using Gaussian frequency shift keying demodulation.

[0011] As a further optimization scheme for microwave signal-energy simultaneous transmission systems based on frequency modulation and amplitude modulation, Gaussian frequency shift keying demodulation can be achieved through two demodulation methods: coherent demodulation and non-coherent demodulation.

[0012] As a further optimization scheme for a microwave signal and energy transmission system based on frequency modulation and demodulation and amplitude modulation, the maximum power point tracking module includes a Boost circuit and its control unit. The Boost circuit control unit calculates the reference value of the rectifier circuit output voltage based on the rectifier circuit output voltage and output current using the MPPT algorithm. After amplifying the error between the sampled value and the reference value of the rectifier circuit output voltage and triggering PWM, it obtains the drive signal of the main switch of the Boost circuit.

[0013] As a further optimization scheme for a microwave signal and energy transmission system based on frequency modulation and demodulation and amplitude modulation, the amplitude modulation converter is a Buck circuit.

[0014] As a further optimization scheme for a microwave signal and energy transmission system based on frequency modulation and demodulation and amplitude modulation, the control unit calculates the reference value of the output voltage of the amplitude modulation converter based on the input voltage and current of the amplitude modulation converter, as well as the load voltage and load current, through the maximum efficiency point tracking algorithm. After amplifying the error between the sampled value and the reference value of the output voltage of the amplitude modulation converter and triggering PWM, the control unit obtains the drive signal of the main switch of the Buck circuit.

[0015] The present invention, by adopting the above technical solution, has the following beneficial effects:

[0016] (1) The present invention proposes a microwave information and energy simultaneous transmission system based on frequency modulation and demodulation and amplitude modulation. A frequency modulator is added to the front stage of the power amplifier at the transmitting end for information loading, and an amplitude modulation converter is placed at the power amplifier power supply end for system power adjustment and efficiency optimization. The frequency modulator and amplitude modulation converter are used for frequency and energy control, respectively, so that information transmission and energy transmission are integrated but do not interfere with each other, and truly realize the efficient synchronous transmission of microwave information and energy.

[0017] (2) In the system architecture, the present invention adopts a maximum power point tracking module and an amplitude modulation converter to optimize the system efficiency from both the perspective of transmission power and load. Only one MPPT converter is added between the rectifier circuit and the load at the receiving end to achieve effective improvement in system-level efficiency. Among them, the maximum power point tracking module, from the perspective of load, keeps the output impedance of the rectifier circuit at the optimal impedance, thereby maximizing the output power / efficiency of the rectifier circuit. From the perspective of transmission power, the amplitude modulation converter, in conjunction with the maximum efficiency point tracking algorithm, dynamically adjusts the output voltage of the amplitude modulation converter, thereby adjusting the output power of the power amplifier and the transmission power of the system, so that the power amplifier and rectifier circuit can work in the region with higher efficiency as much as possible, thereby achieving overall efficiency optimization of the power transmission system. Attached Figure Description

[0018] Figure 1 This is a diagram of the microwave signal and energy transmission system architecture based on frequency modulation and demodulation and amplitude modulation of the present invention.

[0019] Figure 2 This is a schematic diagram of the GFSK modulation principle involved in this invention.

[0020] Figure 3 This is a schematic diagram of the GFSK demodulation principle involved in this invention.

[0021] Figure 4 This is a schematic diagram of the FSK modulation principle involved in this invention.

[0022] Figure 5 This is the power loop diagram of the microwave signal and energy transmission system based on frequency modulation and demodulation and amplitude modulation of the present invention.

[0023] Figure 6 This is the control loop diagram of the microwave signal and energy transmission system based on frequency modulation and demodulation and amplitude modulation of the present invention.

[0024] Explanation of the labels in the diagram: V in ,power supply, S 1. First switching transistor, D 1. First diode, L 1. First inductor, C 1. First capacitor, L 2. Second inductor, S 2. Second switching transistor, D 2. Second diode, C 2. Second capacitor, R L ,load. Detailed Implementation

[0025] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] Figure 1 The diagram shows the architecture of a microwave signal and power transmission system based on frequency modulation and demodulation and amplitude modulation proposed in this invention, including: a microwave signal source, a DC power supply, a frequency modulator, a power amplifier, an amplitude modulation converter, a transmitting antenna, a receiving antenna, a directional coupler, a frequency demodulator, a rectifier circuit, an MPPT (Maximum Power Point Tracking) module, and a control unit. The system consists of: a microwave signal source followed by a frequency modulator for information loading; a power amplifier amplifies the loaded microwave signal before transmitting it to the transmitting antenna; an amplitude modulation converter (AMDC) with its input connected to a DC power supply and its output connected to the power amplifier's power supply; dynamically adjusting the AMDC's output voltage adjusts the power amplifier's output power, i.e., the system's transmission power, allowing the power amplifier and rectifier circuits to operate in their most efficient regions to improve the microwave power transfer system's efficiency; the microwave power signal output from the power amplifier is transmitted to the receiving antenna via the transmitting antenna; a directional coupler splits the microwave power signal received by the receiving antenna, sending one part to a frequency demodulator for demodulation and information analysis, and the other part to a rectifier circuit to convert the microwave power into electrical power for rectification and supply to the load; the MPPT module uses a Boost circuit, with the MPPT's input connected to the rectifier circuit's output and its output connected to the load; the MPPT circuit, from the load perspective, maintains the rectifier circuit's output impedance at its optimal level, maximizing the rectifier circuit's output power / efficiency; and a control unit samples the AMDC's input voltage and current, along with the load voltage and current, and executes the Maximum Power Measure (MPPT) function. The Efficiency Point Tracking (EPT) algorithm dynamically adjusts the output voltage reference value of the amplitude modulation converter to achieve maximum efficiency point tracking of the system.

[0027] The frequency modulator uses the GFSK modulation principle to modulate microwave signals. Figure 2 The diagram illustrates the GFSK modulation principle. The digital signal is first passed through a Gaussian filter and then subjected to FSK modulation to obtain the GFSK signal. FSK modulation is primarily achieved through two modulation methods: direct modulation and quadrature modulation. In direct modulation, the modulating signal is applied to the voltage-controlled oscillator (VCO) of a phase-locked loop (PLL) frequency synthesizer, generating output frequency signals at different multiples of a reference frequency. In quadrature modulation, the digital signal is divided into two orthogonal signals that are one symbol apart in time through phase integration. These are then multiplied by the in-phase and quadrature weighting functions of the carrier wave, respectively, and the two signals are synthesized to obtain the GFSK signal.

[0028] The frequency demodulator demodulates the received microwave power signal using the GFSK demodulation principle. Figure 3The diagram illustrates the GFSK demodulation principle. GFSK demodulation primarily obtains the baseband signal through coherent and incoherent demodulation methods. Coherent demodulation involves multiplying the local carrier signal with the received signal and then passing the result through a low-pass filter to obtain the original modulated signal. Incoherent demodulation relies on envelope detection based on the characteristics of the received signal.

[0029] Figure 4 The diagram illustrates the principle of FSK modulation, which involves keeping the signal amplitude constant while transmitting information by changing the signal frequency. For example, frequency f1 represents the digital signal "1", and frequency f2 represents the digital signal "0". By providing two carrier signals with different frequencies, FSK signals can be obtained through frequency modulation based on the digital signals.

[0030] Figure 5 The diagram shows a microwave signal-powered simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation, along with its efficiency optimization method. The power circuit includes an amplitude modulation converter, an "electric-microwave-electric" unit, and an MPPT module. The amplitude modulation converter employs a Buck circuit and is powered by a DC power supply. V in First switching transistor S 1. First diode D 1. First inductor L 1 and the first capacitor C 1. Composition. The MPPT module uses a Boost circuit, consisting of a second inductor. L 2. Second switching transistor S 2. Second diode D 2. Second capacitor C The system consists of two components. The "electric-microwave-electric" unit comprises a power amplifier, transmitting antenna, receiving cable, directional coupler, and rectifier circuit, realizing the conversion of electrical power to microwave power and back to electrical power. The MPPT module and amplitude modulation converter constitute the electrical power conversion unit, realizing the power / efficiency improvement of the receiver rectifier circuit and the system-level efficiency optimization.

[0031] Figure 6 The diagram shows two control loops for a microwave signal-to-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation, along with its efficiency optimization method. These loops are the maximum power point tracking (MPPT) loop and the maximum efficiency point tracking (MPPT) loop, respectively. The MPPT module samples the output voltage of the rectifier circuit. v rect and output current i rect The MPPT algorithm is used to calculate the reference value of the rectifier circuit output voltage. v rect_ref The first error amplifier provides feedback signal to the output voltage of the rectifier circuit. v rect With reference signal v rect_refAfter the error is amplified, the second switching transistor is obtained through the first PWM comparator. S The drive signal for step 2. The control unit samples the input voltage of the amplitude modulation converter. v in and input current i in and load voltage v o and load current i o The reference value of the output voltage of the amplitude modulation converter is calculated using the MEPT algorithm. v PA_ref The output voltage feedback signal of the amplitude modulation converter is processed by the second error amplifier. v PA With reference signal v PA_ref After the error is amplified, it is used by the second PWM comparator to obtain the first switching transistor. S The driving signal is 1. The MPPT and MEPT algorithms can be implemented using existing algorithms such as the perturbation-observation method.

[0032] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A microwave signal-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation, characterized in that, include: A microwave signal source is used to generate microwave signals; A DC power supply, used to generate DC power; Frequency modulators are used to load information into microwave signals; A power amplifier amplifies the power of a microwave signal after it has been loaded with information by a frequency modulator, and outputs a microwave power signal. An amplitude modulation converter is used to receive amplitude modulation converter control signals and provide an amplitude-adjustable supply voltage to the power amplifier under the excitation of a DC power supply. Transmitting antenna, used to transmit microwave power signals output by the power amplifier; A receiving antenna is used to receive microwave power signals radiated in space. A directional coupler is used to couple the received microwave power signal to the frequency demodulator and the rectifier circuit respectively according to a certain ratio. A frequency demodulator is used to demodulate the received microwave power signal. A rectifier circuit is used to convert received microwave power signals into electrical power. The maximum power point tracking module is used to supply the load with the output power of the rectifier circuit while ensuring that the rectifier circuit operates at its maximum power point when the load of the rectifier circuit changes. and, The control unit is used to generate amplitude modulation converter control signals based on the input voltage and current of the amplitude modulation converter, as well as the load voltage and load current, while ensuring maximum system-level efficiency.

2. The microwave signal-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation according to claim 1, characterized in that, The frequency modulator loads information into the microwave signal using Gaussian frequency shift keying modulation.

3. The microwave signal-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation according to claim 2, characterized in that, The Gaussian frequency shift keying modulation method first performs Gaussian filtering on the microwave signal, and then performs frequency shift keying modulation on the Gaussian filtered microwave signal. The frequency shift keying modulation is implemented through direct modulation or quadrature modulation.

4. A microwave signal-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation according to claim 2 or 3, characterized in that, The frequency demodulator demodulates the received microwave power signal using Gaussian frequency shift keying demodulation.

5. The microwave signal-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation according to claim 4, characterized in that, The Gaussian frequency shift keying demodulation is achieved through coherent demodulation or incoherent demodulation.

6. The microwave signal-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation according to claim 5, characterized in that, The maximum power point tracking module includes a Boost circuit and its control unit. The Boost circuit control unit calculates the reference value of the output voltage of the rectifier circuit based on the output voltage and output current of the rectifier circuit using the MPPT algorithm. After amplifying the error between the sampled value and the reference value of the output voltage of the rectifier circuit and triggering PWM, it obtains the drive signal of the main switch of the Boost circuit.

7. The microwave signal-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation according to claim 6, characterized in that, The amplitude modulation converter is a Buck circuit.

8. The microwave signal-energy simultaneous transmission system based on frequency modulation / demodulation and amplitude modulation according to claim 7, characterized in that, The control unit calculates the reference value of the output voltage of the amplitude modulation converter based on the input voltage and current of the amplitude modulation converter, as well as the load voltage and current, using the maximum efficiency point tracking algorithm. After amplifying the error between the sampled value and the reference value of the output voltage of the amplitude modulation converter and triggering PWM, it obtains the drive signal of the main switch of the Buck circuit.

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