Method for synchronously transmitting wireless electric energy and multi-channel information based on OFDM (Orthogonal Frequency Division Multiplexing)

Abstract

The invention relates to a wireless electric energy and multipath information synchronous transmission method based on OFDM (Orthogonal Frequency Division Multiplexing), and belongs to the technical field of wireless electric energy transmission. Comprising the following steps: constructing an LCC-LCC compensated topology network, wherein the LCC-LCC compensated topology network comprises a first end and a second end; the first end comprises a power output path and a data output path which share a data transmission transformer; the second end comprises a power receiving path and a data receiving path which share a data transmission transformer; constructing an inverter voltage mathematical model, an equivalent resistance mathematical model and an equivalent impedance mathematical model according to the LCC-LCC compensated topology network; and performing wireless electric energy and multi-channel information synchronous transmission based on the inverter voltage mathematical model, the equivalent resistance mathematical model and the equivalent impedance mathematical model. According to the invention, two times of independent data transmission can be realized only by using one data transmission transformer, and a sampling circuit and a filter circuit are not needed, so that the system structure is greatly simplified.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and more specifically, to a method for synchronous transmission of wireless power and multiplexed information based on OFDM. Background Technology

[0002] Wireless power transfer (WPT) is a technology that relies on electromagnetic coupling between the power supply and load sides to transfer energy across space. WPT offers advantages such as convenience, no mechanical wear, and small footprint. It has been applied in areas such as electric vehicle (EV) charging, biomedical implants, smart homes, wireless power supply for automated guided vehicles (AGVs) and autonomous underwater vehicles (AUVs), and implantable medical devices. Based on different power supply principles, it can be categorized into electromagnetic radiation, electric field coupling, magnetic coupling induction, and magnetic coupling resonant technologies. Magnetic coupling resonant wireless power transfer technology, as an emerging technology, has developed rapidly and generated significant interest in the field. It is currently considered one of the most promising wireless power transfer methods.

[0003] Methods for achieving simultaneous wireless power supply and data transmission (SWPIT) mainly include split-channel and shared-channel transmission techniques. Split-channel transmission achieves simultaneous power and data transmission by adding an additional physical channel, primarily employing technologies such as Near Field Communication (NFC), Bluetooth, Wi-Fi, and ZigBee. However, these methods require complex pairing between the transmitter and receiver, leading to significant communication latency and making them unsuitable for certain specialized applications, such as real-time feedback control. Furthermore, data transmission can also be achieved using additional coupling coils, but this method must account for interference between the power and data transmission coils, increasing system complexity. Existing shared-channel transmission techniques achieve simultaneous power and data transmission using the same physical channel. Their simplicity and reliability have led to their widespread application in SWPIT systems. However, existing shared-channel transmission techniques are largely limited to unidirectional and single-path transmission, significantly restricting the data transmission capacity. Summary of the Invention

[0004] In view of the shortcomings of the prior art, this invention provides a method for synchronous transmission of wireless power and multiplexed information based on OFDM. In this application, power transmission employs a bilateral LCC compensation structure to suppress high-order harmonics generated by the inverter, achieving load-independent current output. The data transmission circuit uses a dual-LC resonant network. Power transmission and data transmission can be achieved through a single data transmission transformer, enabling two independent data transmissions.

[0005] The technical means employed in this invention are as follows: A method for synchronous transmission of wireless power and multiplexed information based on OFDM includes the following steps: S1. Construct an LCC-LCC compensation topology network, wherein the LCC-LCC compensation topology network includes a first end and a second end; the first end includes a power output path and a data output path of a shared data transmission transformer; the second end includes a power receiving path and a data receiving path of a shared data transmission transformer. S2. Construct mathematical models of inverter voltage, equivalent resistance, and equivalent impedance based on the LCC-LCC compensation topology network. S3. Based on the inverter voltage mathematical model, equivalent resistance mathematical model and equivalent impedance mathematical model, perform wireless power and multi-channel information synchronous transmission.

[0006] Furthermore, the first end also includes a reverse signal receiving path that shares a data transmission transformer with the power output path and the data output path; the second end also includes a reverse signal output path that shares a data transmission transformer with the power receiving path and the data receiving path.

[0007] Furthermore, based on the aforementioned inverter voltage mathematical model, equivalent resistance mathematical model, and equivalent impedance mathematical model, wireless power and multi-channel information synchronous transmission are performed, including: S301. Set the power carrier frequency to 85kHz; S302. Set the carrier frequencies of the four signals to 3, 5, 7, and 9 times the frequency of the power carrier, i.e., 255kHz, 425kHz, 595kHz, and 765kHz. S303. Four different digital baseband signals carrying information are loaded onto four data carriers through ASK modulation. Since these carriers are orthogonal to each other, they do not interfere with each other. S304. Four modulated waves are loaded onto the circuit through the data transmission transformer, and the composite wave is received on the data receiving transformer. S305. Multiply the composite wave with the waveform of the corresponding frequency to be demodulated. After passing through the integrator circuit, based on the OFDM principle, the integral of the waveform of the corresponding frequency multiplied with other frequency waveforms is 0. When the integral of the waveform to be demodulated is 1, it is not 0. S306. Select a comparison threshold to restore the original information. The threshold is selected as half the difference between the integral average of several data "1" and the average of several data "0".

[0008] Furthermore, the power output path includes a DC power supply, a full-bridge inverter, loosely coupled coils, and a bilateral LCC network; The data output path includes a modulation data source, a dual LC network, and a data coupling transformer; The power receiving path includes a full-bridge rectifier circuit and a load; The data receiving path includes a data demodulation module.

[0009] Furthermore, the mathematical model for the inverter voltage and the mathematical model for the equivalent resistance are as follows:

[0010] in, Indicates DC power supply. Indicates the inverter voltage. Indicates the load resistance. Indicates the rectifier bridge and load The equivalent resistance.

[0011] Furthermore, the mathematical model for the equivalent impedance is as follows:

[0012]

[0013]

[0014] In the forward data transmission path: It is the impedance of the secondary signal path. It is the overall impedance of the secondary side of the main circuit. It is the equivalent impedance of the circuit after the port of the primary-side signal coupling transformer in the data transmission path. , It is the self-impedance of the data transmission circuit when transmitting data 1 and data 2; In the reverse pathway: It is the impedance of the primary-side signal path. It is the overall impedance of the primary side of the main circuit. It is the equivalent impedance of the circuit after the secondary signal transmitting transformer port in the signal path. , It is the total impedance of the self-impedance signal transmission path of the data transmission circuit in the forward and reverse directions when transmitting data 3 and data 4. L1, L2, L3, L4 and C1, C2, C3, C4 represent the inductance and capacitance values ​​of the signal carrier resonant network of the corresponding signal source Us1, Us2, Us3, Us4. In the power transmission channel: It is the total impedance on the secondary receiving side. It is the equivalent impedance of all circuit components to the right of the original resonant capacitor. It is the total impedance of the primary-side emitter. It is the equivalent impedance after the total impedance of the secondary side is converted to the impedance of the primary side. , , These are the resonant inductance and resonant capacitance in the primary-side LCC resonant network. , , These are the resonant inductor and resonant capacitor in the secondary resonant network LCC resonant network, respectively. , and , It is the self-inductance value of the primary and secondary data transmission transformers. , It is the self-inductance value of the primary and secondary sides of the loosely coupled coil. , This represents the mutual inductance between the primary and secondary sides of the data transmitting transformer, where M is the mutual inductance of the loosely coupled coil.

[0015] Compared with the prior art, the present invention has the following advantages: 1. The method for synchronous transmission of wireless power and multiplexed information based on OFDM provided by the present invention has the advantages of low power interference when demodulating the original signal using OFDM principle because the carriers are orthogonal to each other, thus eliminating crosstalk between different frequency information.

[0016] 2. The OFDM-based method for synchronous transmission of wireless power and multiplexed information provided by this invention has a high data carrier bandwidth utilization rate because each data carrier is separated by only one power frequency.

[0017] 3. The present invention provides a method for synchronous transmission of wireless power and multiple information based on OFDM, which proposes a dual lc resonant network and uses a transformer to realize the transmission of multiple data.

[0018] 4. The OFDM-based method for synchronous transmission of wireless power and multiplexed information provided by this invention does not require sampling circuits and filtering networks, which greatly simplifies the circuit structure. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of a method for synchronous transmission of wireless power and multiplexed information based on OFDM in an embodiment of the present invention.

[0021] Figure 2 is a schematic diagram of the OFDM-based wireless power and multiplex information synchronous transmission system in an embodiment of the present invention.

[0022] Figure 3 This is an equivalent circuit diagram for forward data transmission in an embodiment of the present invention.

[0023] Figure 4 This is an equivalent circuit diagram for backward data transmission in an embodiment of the present invention.

[0024] Figure 5 This is an equivalent circuit diagram of power transmission in an embodiment of the present invention.

[0025] Figure 6 This is a full-duplex four-channel data demodulation diagram in an embodiment of the present invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] like Figure 1 As shown, the present invention provides 1. a method for synchronous transmission of wireless power and multiplexed information based on OFDM, characterized by comprising the following steps: S1. Construct an LCC-LCC compensation topology network, wherein the LCC-LCC compensation topology network includes a first end and a second end; the first end includes a power output path and a data output path of a shared data transmission transformer; the second end includes a power receiving path and a data receiving path of a shared data transmission transformer.

[0029] In a preferred embodiment of the present invention, the topology constructed in S1 consists of a power transmission channel and a data transmission channel. The power transmission channel comprises a DC power supply, a full-bridge inverter, loosely coupled coils, a bilateral LCC network, a full-bridge rectifier circuit, and a load RL. The data transmission channel comprises a modulation data source, a dual-LC network, a data coupling transformer, and a data demodulation module. The data transmission circuit employs a dual-LC resonant network, simultaneously transmitting data from both channels by sharing a single data transmission transformer. In the data receiving circuit, only one shared data receiving transformer is used to extract the data transmitted from the two opposite channels.

[0030] More preferably, as shown in Figure 2, the first end further includes a reverse signal receiving path that shares a data transmission transformer with the power output path and the data output path; the second end further includes a reverse signal output path that shares a data transmission transformer with the power receiving path and the data receiving path.

[0031] S2. Construct mathematical models of inverter voltage, equivalent resistance, and equivalent impedance based on the LCC-LCC compensation topology network.

[0032] In a preferred embodiment of the present invention, step 2 includes the following steps: The expressions for inverter voltage and equivalent resistance are as follows:

[0033] in, Indicates DC power supply. Indicates the inverter voltage. Indicates the load resistance. Indicates the rectifier bridge and load The equivalent resistance.

[0034] The mathematical model for equivalent impedance is as follows:

[0035]

[0036]

[0037] Among them, such as Figure 3 As shown, in the forward data transmission path: It is the impedance of the secondary signal path. It is the overall impedance of the secondary side of the main circuit. It is the equivalent impedance of the circuit after the port of the primary-side signal coupling transformer in the data transmission path. , This is the self-impedance of the data transmission circuit when transmitting data 1 and data 2. For example... Figure 4 As shown, in the reverse path: It is the impedance of the primary-side signal path. It is the overall impedance of the primary side of the main circuit. It is the equivalent impedance of the circuit after the secondary signal transmitting transformer port in the signal path. , This refers to the total impedance of the self-impedance signal transmission path of the data transmission circuit during the forward and reverse transmission of data 3 and data 4. L1, L2, L3, L4 and C1, C2, C3, C4 represent the inductance and capacitance values ​​of the corresponding Us1, Us2, Us3, and Us4 channel signal carrier resonant networks. Figure 5 As shown, in the power transmission channel, Zs is the total impedance of the secondary receiving side, Z'P is the equivalent impedance of all circuit elements to the right of the primary resonant capacitor, Zp is the total impedance of the primary transmitting end, and Zsp is the equivalent impedance of the secondary total impedance after being converted to the primary side. , , These are the resonant inductance and resonant capacitance in the primary-side LCC resonant network. , , These are the resonant inductor and resonant capacitor in the secondary resonant network LCC resonant network, respectively. , and , It is the self-inductance value of the primary and secondary data transmission transformers. , It is the self-inductance value of the primary and secondary sides of the loosely coupled coil. , This represents the mutual inductance between the primary and secondary sides of the data transmitting transformer. M is the mutual inductance of the loosely coupled coil.

[0038] To maintain symmetry, the simplified data transformer and dual lc resonant network are as follows.

[0039]

[0040] in, , It is the mutual inductance between the primary and secondary data receiving transformers.

[0041] S3. Based on the inverter voltage mathematical model, equivalent resistance mathematical model and equivalent impedance mathematical model, perform wireless power and multi-channel information synchronous transmission.

[0042] In one implementation of the present invention, step 3) includes: Step 1: According to the SAE J2954 standard, the standard frequency band for wireless charging of electric vehicles is set at 85 kHz. Therefore, the power carrier frequency is also set to 85 kHz in this application.

[0043] Step 2: Set the carrier frequencies of the four signals to 3, 5, 7, and 9 times the frequency of the power carrier, i.e., 255kHz, 425kHz, 595kHz, and 765kHz. Step 3: Four different digital baseband signals carrying information are loaded onto four data carriers using ASK modulation. Since these carriers are orthogonal to each other, they do not interfere with each other. Figure 3 As shown.

[0044]

[0045] Step 4: Load the four modulated waves onto the circuit through the data transmission transformer, and receive the composite wave on the data receiving transformer; Step 5: Multiply the composite wave with the waveform corresponding to the frequency to be demodulated. After passing through an integrator circuit, based on the OFDM principle, if the integral result of multiplying two sine waves is 0, then the two sine waves can be considered orthogonal. The integral result of multiplying orthogonal waveforms is 0, while the integral result of integrating with the waveform to be demodulated is not 0.

[0046]

[0047] Step 6: Select a comparison threshold to reconstruct the original information. This threshold is chosen as half the difference between the integral average of several data "1"s and the average of several data "0"s. In this application, the amplitude of data 1 is not necessarily 1, but it must have an amplitude. The amplitude of data 0 is theoretically 0, but due to parameter errors, it may have a very small amplitude. Using the threshold selection method given in this step can effectively reduce the bit error rate of comparison reconstruction.

[0048] Furthermore, the method of this application also includes: S4. Establish and verify a simulation model of a wireless power and multiplexed information synchronous transmission system based on OFDM. For example... Figure 6 As shown, this invention can effectively separate four mixed signals and demodulate the 0 and 1 signals carried by each modulation carrier. Simultaneously, while ensuring full-duplex communication, each channel can transmit at a high efficiency of 48 kbit / s, exhibiting good signal transmission performance.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synchronous transmission of wireless power and multiplexed information based on OFDM, characterized in that, Includes the following steps: S1. Construct an LCC-LCC compensation topology network, wherein the LCC-LCC compensation topology network includes a first end and a second end; the first end includes a power output path and a data output path of a shared data transmission transformer; the second end includes a power receiving path and a data receiving path of a shared data transmission transformer. S2. Construct mathematical models of inverter voltage, equivalent resistance, and equivalent impedance based on the LCC-LCC compensation topology network. S3. Based on the inverter voltage mathematical model, equivalent resistance mathematical model and equivalent impedance mathematical model, perform wireless power and multi-channel information synchronous transmission.

2. The method for synchronous transmission of wireless power and multiplexed information based on OFDM according to claim 1, characterized in that, The first end also includes a reverse signal receiving path that shares a data transmission transformer with the power output path and the data output path; the second end also includes a reverse signal output path that shares a data transmission transformer with the power receiving path and the data receiving path.

3. The method for synchronous transmission of wireless power and multiplexed information based on OFDM according to claim 1, characterized in that, Based on the aforementioned inverter voltage mathematical model, equivalent resistance mathematical model, and equivalent impedance mathematical model, wireless power and multi-channel information synchronous transmission are performed, including: S301. Set the power carrier frequency to 85kHz; S302. Set the carrier frequencies of the four signals to 3, 5, 7, and 9 times the frequency of the power carrier, i.e., 255kHz, 425kHz, 595kHz, and 765kHz. S303. Four different digital baseband signals carrying information are loaded onto four data carriers through ASK modulation. Since these carriers are orthogonal to each other, they do not interfere with each other. S304. Four modulated waves are loaded onto the circuit through the data transmission transformer, and the composite wave is received on the data receiving transformer. S305. Multiply the composite wave with the waveform of the corresponding frequency to be demodulated. After passing through the integrator circuit, based on the OFDM principle, the integral of the waveform of the corresponding frequency multiplied with other frequency waveforms is 0. When the integral of the waveform to be demodulated is 1, it is not 0. S306. Select a comparison threshold to restore the original information. The threshold is selected as half the difference between the integral average of several data "1" and the average of several data "0".

4. The method for synchronous transmission of wireless power and multiplexed information based on OFDM according to claim 1, characterized in that, The power output path includes a DC power supply, a full-bridge inverter, loosely coupled coils, and a bilateral LCC network; The data output path includes a modulation data source, a dual LC network, and a data coupling transformer; The power receiving path includes a full-bridge rectifier circuit and a load; The data receiving path includes a data demodulation module.

5. The method for synchronous transmission of wireless power and multiplexed information based on OFDM according to claim 1, characterized in that, The mathematical models for inverter voltage and equivalent resistance are as follows: in, Indicates DC power supply. Indicates the inverter voltage. Indicates the load resistance. Indicates the rectifier bridge and load The equivalent resistance.

6. The method for synchronous transmission of wireless power and multiplexed information based on OFDM according to claim 1, characterized in that, The mathematical model for the equivalent impedance is as follows: In the forward data transmission path: It is the impedance of the secondary signal path. It is the overall impedance of the secondary side of the main circuit. It is the equivalent impedance of the circuit after the port of the primary-side signal coupling transformer in the data transmission path. , It is the self-impedance of the data transmission circuit when transmitting data 1 and data 2; In the reverse pathway: It is the impedance of the primary-side signal path. It is the overall impedance of the primary side of the main circuit. It is the equivalent impedance of the circuit after the secondary signal transmitting transformer port in the signal path. , It is the total impedance of the self-impedance signal transmission path of the data transmission circuit in the forward and reverse directions when transmitting data 3 and data 4. L1, L2, L3, L4 and C1, C2, C3, C4 represent the inductance and capacitance values ​​of the signal carrier resonant network of the corresponding signal source Us1, Us2, Us3, Us4. In the power transmission channel: It is the total impedance on the secondary receiving side. It is the equivalent impedance of all circuit components to the right of the original resonant capacitor. It is the total impedance of the primary-side emitter. It is the equivalent impedance after the total impedance of the secondary side is converted to the impedance of the primary side. , , These are the resonant inductance and resonant capacitance in the primary-side LCC resonant network. , , These are the resonant inductor and resonant capacitor in the secondary resonant network LCC resonant network, respectively. , and , It is the self-inductance value of the primary and secondary data transmission transformers. , It is the self-inductance value of the primary and secondary sides of the loosely coupled coil. , This represents the mutual inductance between the primary and secondary sides of the data transmitting transformer, where M is the mutual inductance of the loosely coupled coil.

Images