Rotary structure wireless energy and data synchronous transmission system based on harmonic modulation

Abstract

The invention relates to the technical field of wireless energy and data synchronous transmission, particularly discloses a rotary structure wireless energy and data synchronous transmission system based on harmonic modulation, and aims to solve the problems of high cost and complex structure caused by the fact that a high-frequency data carrier generator needs to be additionally arranged in a traditional synchronous transmission scheme. Higher harmonics in a multiplexing energy transmission channel are used as data carriers. LC series networks tuned at an energy carrier frequency are respectively arranged on a primary side and a secondary side of the system, and amplitude keying modulation is performed on higher harmonics generated by an inverter by controlling connection and disconnection of a data capacitor connected with the LC series networks in parallel, so that data loading is realized; and the receiving end demodulates the data by detecting the voltage change of the inductor, filtering, detecting and shaping. The system does not need an independent data carrier generator, reduces the cost and complexity, simplifies the filter design because the data carrier frequency is much higher than the energy carrier frequency, and is especially suitable for space limited scenes such as a rotation structure.

Description

Harmonic Modulation-Based Rotating Structure Wireless Power and Data Synchronization Transmission System Technical Field

[0001] This invention relates to the field of wireless power and data synchronization transmission technology, and more particularly to a rotating structure wireless power and data synchronization transmission system based on harmonic modulation. Background Technology

[0002] Rotating structures play a crucial role in various devices. Electrical connections between static and rotating components are typically achieved through slip rings. Mechanical conductive slip rings achieve power and data transmission through dynamic contact between brushes and conductive rings, making them widely used in applications requiring unlimited 360-degree rotation, such as robot joints, wind turbines, solar arrays, and drilling. However, due to inherent mechanical limitations, traditional conductive slip rings suffer from several key drawbacks, including limited lifespan, a high risk of generating electrical sparks, insufficient operational safety, and high maintenance costs associated with brush replacement. Furthermore, traditional slip rings generate drag torque during rotation. Given that the frictional contact interfaces of these components are made of metallic materials, wear during operation generates metal debris. These suspended particulate contaminants can trigger electrical short-circuit faults, thereby compromising the operational reliability of the entire conductive slip ring system.

[0003] These problems with traditional slip rings can be solved using wireless power transfer (WPT) technology, which transmits electrical energy without electrical contact. Due to its safety, stability, and flexibility, WPT technology has attracted widespread attention from researchers. In practical applications, such as rotary steered drilling tools in oil drilling, bidirectional data transmission is required in addition to electrical power transmission. The SWPDT (Wireless Power and Data Transmission) system effectively meets the need to transmit commands from the surface system to the steering unit, and to upload near-bit measurement data and steering unit status parameters back to the surface system. This system effectively achieves synchronous transmission of power and data, meeting the specific requirements of the application.

[0004] To implement SWPDT on top of an existing WPT system, an additional data coil is typically added to the coupler for data transmission. However, this additional data coil increases the coupler size and reduces the system's power density. Multiplexing the inherent power transmission coil can solve this problem. Two types of SWPDT systems have been proposed: one that transmits data by modulating a power carrier, and another that transmits data by modulating a data carrier. In a power carrier-based SWPDT system, the data signal is generated by directly modulating the power carrier. However, the power transmission efficiency of this system is affected by the data transmission, and the data rate is limited by the power carrier frequency. When amplitude shift keying (APS) modulation is used for data transmission, the amplitude of the power carrier varies depending on the transmitted data. Common methods for adjusting the carrier amplitude include modulating the inverter's output voltage or adjusting the resonant parameters of the compensation network, which can affect power transmission capability and efficiency. If frequency shift keying (FSK) modulation is used, the power carrier frequency is typically adjusted. This will deviate the system from its optimal operating point, similarly affecting power transmission performance and efficiency. In a data carrier-based SWPDT system, a dedicated high-frequency data carrier is used for data transmission, which has minimal impact on the power carrier and allows for higher data rates. However, previous studies have required an additional data carrier generator to produce high-frequency data carriers, which incurs additional costs. Summary of the Invention

[0005] This invention provides a rotating structure wireless power and data synchronization transmission system based on harmonic modulation. The technical problem it solves is that traditional SWPDT systems require a dedicated data carrier generator to generate high-frequency data carriers, which brings corresponding costs.

[0006] To address the above technical problems, this invention provides a wireless power and data synchronization transmission system for a rotating structure based on harmonic modulation, comprising a primary side and a secondary side for the rotating structure, wherein the primary side includes a DC voltage source. Full-bridge inverter, primary coil Connected to the output terminal and primary coil of the full-bridge inverter. Power transfer compensation capacitor between one end And connected to the other output terminal and primary coil of the full-bridge inverter. The primary signal circuit is located at the other end; the secondary side includes a secondary coil. Secondary signal circuit, rectifier and load resistor ;

[0007] The primary signal circuit includes components connected in parallel to the other output terminal of the full-bridge inverter and the primary coil. The other end includes a primary LC series network and a primary modulation circuit, and also includes a primary demodulation circuit; the data carrier frequency of the primary modulation circuit... The operating frequency of the full-bridge inverter of times, The harmonic order of the full-bridge inverter output voltage selected for data transmission; the primary demodulation circuit acquires the inductance in the primary LC series network. Demodulate the voltage;

[0008] The secondary signal circuit adopts a structure symmetrical to the primary signal circuit, and a parallel secondary harmonic short-circuit capacitor is added before the rectifier. .

[0009] Preferably, the secondary signal circuit excludes the secondary harmonic short-circuit capacitor. In addition, it also includes parallel connection to the secondary coil. A secondary LC series network and a secondary modulation circuit are connected between one end of the rectifier and one end of the secondary LC series network, and a secondary demodulation circuit is also included; the secondary demodulation circuit acquires the inductance in the secondary LC series network. The voltage is demodulated; the data carrier frequency of the secondary modulation circuit is the same as that of the primary modulation circuit.

[0010] Preferably, the primary modulation circuit includes a data capacitor connected in series. The secondary modulation circuit includes a switch SPST1, and a data capacitor connected in series. .

[0011] Preferably, the primary LC series network includes inductors connected in series. and capacitor The secondary LC series network includes capacitors connected in series. and inductor .

[0012] Preferably, when data needs to be transmitted from the primary side to the secondary side in a forward direction, control switch SPST2 remains on, and the switching frequency of switch SPST1 between on and off is [missing information]. When data needs to be transmitted in reverse from the secondary side to the primary side, control switch SPST1 remains on, and switch SPST2 switches between on and off at a frequency of [frequency missing]. .

[0013] Preferably, the primary demodulation circuit and the secondary demodulation circuit use the same data demodulation module, which includes a bandpass filter, an envelope detector, and a hysteresis voltage comparator, and an inductor. voltage or inductance The voltage input is filtered by the bandpass filter and then input to the envelope detector to extract the envelope. The hysteresis voltage comparator is used to shape the envelope into a square wave to obtain the data signal.

[0014] Preferably, , , ,as well as , , These are the equivalent on-resistances of switches SPST1 and SPST2, respectively.

[0015] Preferably, , Is with The corresponding angular frequency; , For leakage inductance reflected to the primary side, Primary coil With secondary coil Mutual attraction between them.

[0016] Preferably, , for and The center frequency.

[0017] Preferably, the system parameter design process includes the following steps:

[0018] S1. Determine the power carrier frequency based on transmission power and application. and the dimensions and parameters of the coupling mechanism. , ;

[0019] S2, according to Calculate capacitance The value;

[0020] S3. Determine a set of series network inductors. and The value;

[0021] S4, according to Calculate capacitance and The value;

[0022] S5, Judgment and If the impact of internal resistance on transmission efficiency is less than the efficiency threshold, proceed to the next step; otherwise, return to step S3 and re-determine a set of series network inductors. and The value;

[0023] S6, Confirm and center frequency ;

[0024] S7, according to Calculate capacitance and The value;

[0025] S8, Judgment and If the impedance of the fundamental wave of electrical energy is greater than the impedance threshold, then calculate the transfer function and amplitude-frequency diagram of the forward and reverse data transmission channels respectively.

[0026] S9. Determine the maximum gain frequency point based on the transfer function and amplitude-frequency diagram. ;

[0027] S10. Determine the maximum gain frequency point. Is it a high-order harmonic of the inverter output? If yes, proceed to the next step; otherwise, return to step S6.

[0028] S11. Determine the maximum gain frequency point Is it more important than the frequency of electric power carrier waves? At least an order of magnitude higher, or if so, based on the current... This is the data carrier frequency.

[0029] This invention provides a wireless power and data synchronization transmission system for rotating structures based on harmonic modulation. This system is primarily used in space-constrained environments such as rotating machinery, enabling bidirectional data transmission while wirelessly transmitting power. Its core innovation lies in reusing high-order harmonics in the power transmission channel as data carriers, thereby eliminating the need for an additional high-frequency data carrier generator in traditional systems, simplifying the system structure and reducing costs.

[0030] Specifically, the system employs a series-without (SN) compensation topology to achieve efficient power transmission, and sets up LC series networks tuned to the power carrier frequency on both the primary and secondary sides. Through data capacitors connected in parallel to this network and their control switches (SPST1, SPST2), the system can perform amplitude-keying modulation on the naturally generated high-order harmonics during power transmission, thereby achieving data loading and transmission. The receiving end demodulates the transmitted data by detecting changes in the harmonic voltage on the corresponding inductor.

[0031] The advantages of this system are mainly reflected in the following aspects:

[0032] Independent carrier modulation: Modulation is performed using an independent data carrier (i.e., power harmonics) instead of directly modulating the power carrier, thereby minimizing the impact on power transmission efficiency and stability;

[0033] Harmonic multiplexing reduces costs: It directly uses the inherent high-order harmonics in the inverter output voltage as data carriers, eliminating the need for additional high-frequency signal generation circuits, resulting in a simpler system structure and lower costs.

[0034] Stable signal-to-noise ratio: The amplitude of harmonic voltage is proportional to the fundamental power voltage, so that the signal-to-noise ratio of the data transmission channel naturally changes synchronously with the power transmission level, which enhances the anti-interference capability of the system.

[0035] Compact structure, suitable for rotating scenarios: By reusing the same set of coupling coils to transmit energy and data simultaneously, the number of additional components is reduced, making it particularly suitable for rotating structure applications with limited installation space;

[0036] High frequency separation and simple filter design: Using a higher-order harmonic as the data carrier, making its frequency much higher than the power carrier frequency, helps to simplify the design of the bandpass filter at the receiver and improve the reliability of data transmission. Attached Figure Description

[0037] Figure 1 is a circuit diagram of a rotating structure wireless power and data synchronization transmission system based on harmonic modulation provided in an embodiment of the present invention;

[0038] Figure 2 is a structural diagram of the data demodulation module provided in an embodiment of the present invention;

[0039] Figure 3 is an equivalent circuit diagram of the power transmission channel provided in an embodiment of the present invention;

[0040] Figure 4 is a full-fundamental reference model diagram of the SN compensation topology provided in an embodiment of the present invention;

[0041] Figure 5 is a system equivalent circuit diagram for bidirectional transmission provided in an embodiment of the present invention. In Figure 5(a), the equivalent circuit diagram of the forward data transmission channel is shown, and in Figure 5(b), the equivalent circuit diagram of the reverse data transmission channel is shown.

[0042] Figure 6 shows the situation provided in an embodiment of the present invention when SPST1 is on and SPST2 is off. The waveform and its Fast Fourier Transform (FFT) result are shown in Figure 6(a). The calculated waveform is shown in Figure 6(b), which is the result of Fast Fourier Transform (FFT).

[0043] Figure 7 shows the situation when SPST1 and SPST2 are disconnected according to an embodiment of the present invention. The waveform and its Fast Fourier Transform (FFT) result are shown in Figure 7(a). The calculated waveform is shown in Figure 7(b), which is the result of Fast Fourier Transform (FFT).

[0044] Figure 8 illustrates the states of SPST1 when it is turned on and when it is turned off, according to an embodiment of the present invention. The Bode plot of the transmission gain of the forward data transmission channel is shown in Figure 8. (a) corresponds to when SPST1 is turned on, and (b) corresponds to when SPST1 is turned off.

[0045] Figure 9 illustrates the states provided in this embodiment of the invention when SPST2 is on and off. The Bode plot of the transmission gain of the reverse data transmission channel is shown in Figure 9(a), which corresponds to when SPST2 is turned on, and Figure 9(b), which corresponds to when SPST2 is turned off.

[0046] Figure 10 illustrates the following scenarios according to an embodiment of the present invention: when SPST1 is disconnected and SPST2 is connected, and when SPST2 is disconnected and SPST1 is connected. and The waveform diagram, in Figure 10(a) corresponds to when SPST1 is off and SPST2 is on. Figure 10(b) corresponds to the situation where SPST2 is off and SPST1 is on. ;

[0047] Figure 11 is a flowchart of system parameter design provided in an embodiment of the present invention;

[0048] Figure 12 is an experimental waveform diagram of the data transmission channel provided in the embodiment of the present invention. In Figure 11(a), the data forward transmission channel is shown, and in Figure 12(b), the data reverse transmission channel is shown.

[0049] Figure 13 shows the relevant waveforms during forward data transmission provided in the embodiment of the present invention. In Figure 13(a), the waveform of the data transmission channel is shown during forward data transmission, and in Figure 13(b), the waveform is shown when SPST1 is disconnected. The FFT results of the voltage are shown in Figure 13(c), which shows the FFT results when SPST1 is turned on.

[0050] Figure 14 shows the relevant waveforms during data reverse transmission provided in the embodiment of the present invention. In Figure 14(a), the waveform of the data transmission channel is shown during data reverse transmission, and in Figure 14(b), the waveform is shown when SPST2 is disconnected. The FFT results of the voltage are shown in Figure 14(c), which shows the FFT results when SPST2 is turned on.

[0051] Figure 15 shows the waveforms of the power transmission channel and the data transmission channel when power and data are transmitted simultaneously, according to an embodiment of the present invention. In Figure 15(a), the waveform of the power transmission channel is shown, and in Figure 15(b), the waveforms of the power and data transmission channels are shown when power and data are transmitted simultaneously.

[0052] Figure 16 shows the voltage stress measured at the disconnected switch when one switch is disconnected and another switch is connected according to an embodiment of the present invention. In Figure 16(a), the voltage stress of SPST1 is when SPST1 is disconnected and SPST2 is connected. In Figure 16(b), the voltage stress of SPST2 is when SPST2 is disconnected and SPST1 is connected. Detailed Implementation

[0053] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0054] This invention provides a wireless power and data synchronization transmission system based on harmonic modulation for a rotating structure, as shown in the circuit diagram of Figure 1. It includes a primary side and a secondary side for the rotating structure. The primary side includes a DC voltage source. Full-bridge inverter (composed of MOSFETs S1 to S4), primary coil Connected to the output terminal and primary coil of the full-bridge inverter. Power transfer compensation capacitor between one end And connected to the other output terminal and primary coil of the full-bridge inverter. The primary signal circuit is located at the other end. The secondary side includes a secondary coil. Secondary signal circuit, rectifier (composed of diodes D1-D4 and filter capacitors) (Composition) and load resistance Primary coil and secondary coil Mutual induction between express.

[0055] The primary signal circuit includes a circuit connected in parallel to the other output terminal of the full-bridge inverter and the primary coil. The other end includes a primary LC series network and a primary modulation circuit, as well as a primary demodulation circuit. The primary LC series network includes inductors connected in series. and capacitor The primary demodulation circuit acquires data from the inductor. voltage ( Demodulation is performed. The primary modulation circuit includes a data capacitor connected in series. Switch SPST1 (a single-pole single-throw switch with an equivalent on-resistance of...) ).

[0056] The secondary signal circuit adopts a symmetrical structure to the primary signal circuit, and a parallel secondary harmonic short-circuit capacitor is added before the rectifier. That is, the secondary signal circuit excluding the secondary harmonic short-circuit capacitor. In addition, it also includes parallel connection to the secondary coil. The secondary LC series network, the secondary modulation circuit, and the secondary demodulation circuit are connected at one end to the rectifier at the other end. The secondary LC series network includes capacitors connected in series. and inductor The secondary demodulation circuit acquires the inductor. voltage ( Demodulation is performed. The secondary modulation circuit includes a series-connected switch SPST2 (a single-pole single-throw switch with an equivalent on-resistance of...). ) and data capacitor .

[0057] The primary and secondary demodulation circuits use the same data demodulation module, the structure of which is shown in Figure 2. It includes a bandpass filter (BPF), an envelope detector (ED), and a hysteresis voltage comparator (HVC), along with an inductor. voltage ( or inductance voltage ( The input bandpass filter (BPF) filters the signal, and the input envelope detector (ED) extracts the envelope. The hysteresis voltage comparator (HVC) is used to shape the envelope into a square wave to obtain the data signal.

[0058] For the power transmission channel, the center frequency is the power carrier frequency. Primary and secondary LC series networks (i.e.) , and , These can be considered as short circuits to the power carrier, and they satisfy the following equations:

[0059] (1)

[0060] in, Is with The corresponding angular frequency.

[0061] The frequency of the data carrier is defined as The corresponding angular frequency is It is important to note that the frequency of the data carrier is much higher than that of the power carrier.

[0062] The equivalent circuit diagram of the power transmission channel is shown in Figure 3. The commonly used SN compensation topology in strongly coupled wireless power transfer (WPT) systems is shown in the blue dashed box in Figure 3. This is the output voltage of the full-bridge inverter. This is the input voltage of the rectifier. For rectifier and load resistor The equivalent load.

[0063] Figure 4 shows the all-fundamental reference model of the SN-compensated topology. For leakage of the primary side, This refers to the turns ratio between the primary and secondary windings of a transformer. Let be the magnetizing inductor, and the relationship between its parameters satisfies the following equation:

[0064] (2)

[0065] in, Measurements can also be performed on the primary side by short-circuiting the secondary coupling coil.

[0066] exist Place, and The relationship between them is:

[0067] (3)

[0068] In practical applications, when a full-bridge inverter is operating, the inverter's output voltage waveform is a square wave, and its Fourier series can be expressed as:

[0069] (4)

[0070] in, For harmonic order, It is the fundamental frequency.

[0071] As can be seen from equation (4), the output voltage of the full-bridge inverter is composed of high-order harmonics. Using harmonics of a specific order to transmit data, the primary LC series network or the secondary LC series network can be regarded as a short circuit of that harmonic.

[0072] The equivalent circuit of the system during bidirectional transmission is shown in Figure 5. Figure 5(a) is the equivalent circuit diagram of the forward data transmission channel, and Figure 5(b) is the equivalent circuit diagram of the reverse data transmission channel. Indicates the original edge number 1 Voltage of subharmonics The selected harmonic order for data transmission. or The first generated above The subharmonic voltage is used for data demodulation.

[0073] For the Second harmonic, its amplitude and frequency Satisfy the following equation:

[0074] (5)

[0075] When data is transmitted in the forward direction, refer to the equivalent circuit diagram shown in Figure 5(a). , and They flow through , and The data carrier current, the compensation capacitor of the power transmission channel (i.e.) , and The data carrier exhibits low impedance and can be considered a short circuit. According to Kirchhoff's Voltage Law (KVL), the parameters of the data transmission channel satisfy:

[0076] (6)

[0077] Based on the states of switches SPST1 and SPST2, the impedance on the secondary side during forward transmission... and the impedance of the primary side It can be represented as:

[0078] (7)

[0079] (8)

[0080] Flowing The current can be expressed as:

[0081] (9)

[0082] Subharmonics The excitation voltage generated is:

[0083] (10)

[0084] From equations (6) to (10), it can be deduced that the voltage Will follow The data changes with the changes in the primary side. Therefore, data is transmitted from the primary side to the secondary side.

[0085] When data is transmitted in reverse, the equivalent circuit diagram of the reverse data transmission channel is shown in Figure 5(b), where... , and They are respectively flowing through , and The data carrier current. When the data is transmitted in reverse, the following equation can be obtained:

[0086] (11)

[0087] Based on the states of switches SPST1 and SPST2, the impedance on the secondary side during reverse transmission... and the impedance of the primary side It can be represented as:

[0088] (12)

[0089] (13)

[0090] Flowing The current is:

[0091] (14)

[0092] Subharmonics The excitation voltage generated is:

[0093] (15)

[0094] From equations (11) to (15), it can be deduced that the voltage Will follow It changes with the changes. Therefore, reverse data transmission is achieved.

[0095] When data is transmitted in the forward direction, equation (4) represents... The Laplace transform equation is:

[0096] (16)

[0097] in, For the Laplace operator.

[0098] By applying the complex frequency domain form of Kirchhoff's voltage law, the following equation can be derived:

[0099] (17)

[0100] in, and They are Incentives flow and The Laplace function of the current, and These are the total impedances of the primary and secondary sides, respectively.

[0101] Based on the states of switches SPST1 and SPST2 and It can be represented as:

[0102] (18)

[0103] (19)

[0104] Flowing The Laplace equation for the current is:

[0105] (20)

[0106] It can be deduced The image function of the voltage is:

[0107] . (twenty one)

[0108] By applying the inverse Laplace transform to equation (21) ), from which we can deduce The time-domain expression is:

[0109] . (twenty two)

[0110] The main parameter values ​​of the data transmission channel are listed in Table 1 for analysis. When SPST1 is on and SPST2 is off, the parameters listed in Table 1 are used for calculation. The waveform is shown in Figure 6. In Figure 6(a), the waveform is when SPST1 is turned on and SPST2 is turned off. The calculated waveform is shown in Figure 6(b), which is the Fast Fourier Transform (FFT) result of the waveform shown in Figure 6(a).

[0111] Table 1. Main parameters used for data transmission channel analysis

[0112]

[0113] When SPST1 and SPST2 are disconnected, the calculation is performed. The waveform and its Fast Fourier Transform (FFT) result are shown in Figure 7. In Figure 7(a), the waveform is when SPST1 is disconnected and SPST2 is disconnected. The calculated waveform is shown in Figure 7(b), which is the Fast Fourier Transform (FFT) result of the waveform shown in Figure 7(a).

[0114] By comparing the waveforms in Figure 6(a) and Figure 7(a) and the amplitudes in Figure 6(b) and Figure 7(b), it can be inferred that the amplitude of the harmonics changes with the state of SPST1. This indicates that by switching the state of the primary side SPST1, the amplitude of the secondary side harmonics can be adjusted, thereby achieving positive data transmission.

[0115] Based on the above analysis, it can be concluded that at any given moment, data transmission occurs in only one direction, and the data transmission channel operates in half-duplex mode. In traditional, mature, and cost-sensitive industrial applications, the communication mode is relatively simple, and half-duplex communication remains the mainstream, fully meeting the requirements.

[0116] During data transmission, the transmission gain of the data carrier in the forward data transmission channel is:

[0117] . (twenty three)

[0118] The frequency of harmonics is directly proportional to the operating frequency of the inverter. When determined, the frequency of the harmonics This is predetermined. To simplify the analysis, the system parameters are set to symmetric, i.e. , , ,as well as And in order to make in The maximum transfer gain obtained at that point The first derivative should satisfy:

[0119] . (twenty four)

[0120] By solving equation (24), we can obtain , and The relationship between them.

[0121] To visually illustrate this relationship, a Bode plot of data transmission is drawn using the parameters in Table 1 to show the data carrier transmission gain, and the parallel network (i.e., and The center frequency of ) is defined as Then we have:

[0122] (25)

[0123] Figure 8 shows the conditions when (a) SPST1 is on and (b) SPST1 is off. The Bode plot of the transmission gain of the forward data transmission channel. When When changing from 1 MHz to 3 MHz, In the Bode diagram, SPST1 is in the ON state, as shown in Figure 8(a), where the solid line represents SPST2 in the ON state and the dashed line represents SPST2 in the OFF state. As can be seen from Figure 8(a), with... With the increase of SPST2, the maximum transmission gain of the data transmission channel increases, and the maximum transmission gain when SPST2 is on is much greater than its gain when it is off. Furthermore, the frequency points corresponding to the maximum data carrier transmission gain also gradually increase, meaning that the frequency corresponding to the maximum transmission gain can be accessed via... and To adjust. and The value can also be obtained from equation (25).

[0124] When SPST1 is disconnected The Bode plot is shown in Figure 8(b). The solid line represents SPST2 in the on state, while the dashed line represents SPST2 in the off state. As can be seen from Figure 8(b), when SPST2 is off, the transmission gain is almost 0.2, and as… The change remains unchanged. Meanwhile, when SPST2 is activated, the maximum transmission gain of the data transmission channel also changes accordingly. It increases with the increase of.

[0125] Comparing Figure 8(a) and Figure 8(b), it can be deduced that when SPST2 is on, the maximum transmission gain of the data transmission channel when SPST1 is off is almost equal to the maximum gain when SPST1 is on, and the frequency at which the maximum transmission gain is obtained when SPST1 is off is lower than the frequency at which SPST1 is on. In other words, when SPST2 is on and SPST1 is off, the same transmission gain can be obtained at a lower frequency. In practical applications, a lower operating frequency helps to reduce the impact of parasitic parameters on the system. Therefore, forward data transmission adopts the operating mode described by the following formula:

[0126] (26)

[0127] Therefore, when SPST1 is turned on and off, The amplitude of the data carrier voltage switches between low and high levels, and the switching frequency is defined as the data carrier frequency. This successfully transmits data to the secondary side.

[0128] Similar to the forward data transmission channel, the data carrier transmission gain of the reverse data transmission channel can also be obtained as follows:

[0129] (27)

[0130] Figure 9 shows the conditions when (a) SPST2 is on and (b) SPST2 is off. Bode plot of the transmission gain of the reverse data transmission channel. When SPST2 is turned on. The Bode plot is shown in Figure 9(a), where the solid line represents SPST1 being on and the dashed line represents SPST1 being off. As can be seen from Figure 9(a), the reverse data transmission channel and the forward data transmission channel share the same frequency point corresponding to the maximum gain, and the maximum transmission gain when SPST1 is on is much greater than the gain when SPST1 is off.

[0131] When SPST2 is disconnected The Bode plot is shown in Figure 9(b), where the solid line represents SPST1 in the ON state and the dashed line represents SPST1 in the OFF state. As can be seen from Figure 9(b), when SPST1 is ON, the transmission gain of the reverse data transmission channel also increases accordingly. The transmission gain increases with the increase of SPST1; when SPST1 is disconnected, the transmission gain is almost 0.3, and increases with the increase of SPST1. The changes remain unchanged.

[0132] Comparing Figure 9(a) and Figure 9(b), it can be deduced that when SPST1 is on, the maximum transmission gain of the data transmission channel when SPST2 is off is greater than the maximum gain when SPST2 is on, and the frequency point at which the maximum transmission gain is obtained when SPST2 is off is lower than the frequency point when SPST2 is on. Therefore, the reverse data transmission adopts the operating mode described by the following formula:

[0133] (28)

[0134] Its switching frequency is the same as the switching frequency for forward data transmission, which is the data carrier frequency. .

[0135] When electrical energy and data are transmitted simultaneously and share the same coupler, power line carriers introduce significant noise into the data transmission channel.

[0136] When SPST1 is off and SPST2 is on, and when SPST2 is off and SPST1 is on, the Laplace functions of the voltages across SPST1 and SPST2 can be derived based on equations (17) to (19):

[0137] (29)

[0138] Voltage stress , The time-domain expression can be obtained by performing an inverse Laplace transform on equation (29):

[0139] (30)

[0140] Calculate based on the parameters listed in Table 1. and The waveform is shown in Figure 10. and The waveforms are shown in Figure 10(a) and Figure 10(b), respectively.

[0141] Based on the above analysis, the parameter design flow of the rotating structure wireless power and data synchronization transmission system based on harmonic modulation designed in this invention is shown in Figure 11, including the following steps:

[0142] S1. Determine the power carrier frequency based on transmission power and application. and the dimensions and parameters of the coupling mechanism. , and ;

[0143] S2. Calculate the capacitance according to equation (2). The value;

[0144] S3. Determine a set of series network inductors. and The value;

[0145] S4. Calculate the capacitance according to equation (1). and The value;

[0146] S5, Judgment and If the impact of internal resistance on transmission efficiency is less than the efficiency threshold (0.5%), proceed to the next step; otherwise, return to step S3 and re-determine a set of series network inductors. and The value;

[0147] S6. Determine the parallel network ( , )and( , The center frequency of ) ;

[0148] S7. Calculate the capacitance according to equation (25). and The value;

[0149] S8, Judgment and If the impedance of the fundamental wave of the electric energy is greater than the impedance threshold (1 kΩ), then the transfer function and amplitude-frequency diagram of the forward and reverse data transmission channels are calculated according to equation (23);

[0150] S9. Determine the maximum gain frequency point based on the transfer function and amplitude-frequency diagram. ;

[0151] S10. Determine the maximum gain frequency point. Is it a high-order harmonic of the inverter output? If yes, proceed to the next step; otherwise, return to step S6.

[0152] S11. Determine the maximum gain frequency point Is it more important than the frequency of electric power carrier waves? At least an order of magnitude higher, or if so, based on the current... This is the data carrier frequency.

[0153] To verify the feasibility of the proposed SWPDT system, an experimental prototype was built based on Figure 2, including a coupler, auxiliary power supply, inverter, rectifier, oscilloscope, and data transceiver. The data transceiver consists of a modulation module and a demodulation module. In the modulation module, two anti-parallel MOSFETs controlled by the input data act as switches to adjust the amplitude of the data carrier. In the demodulation module, an amplifier acts as a voltage follower to sample the inductor (i.e.,...). and The voltage of the circuit is used to construct a bandpass filter, an envelope demodulator is used to extract the envelope of the filtered waveform, and a hysteresis voltage comparator is used to shape the envelope into a square wave. The main parameters of the prototype are listed in Table 2.

[0154] Table 2 Main parameters used for experimental verification

[0155]

[0156] In selecting the harmonic order, to improve the signal-to-noise ratio (SNR), higher transmission gain and input voltage should be prioritized. From equation (4), it can be deduced that as the harmonic frequency increases, the amplitude of the harmonic voltage decreases. Furthermore, it can be deduced from the above that the frequency of maximum transmission gain is... With parallel networks (i.e.) , and , The center frequency of ) Related, and it can be inferred from Figure 9 that, (The frequency of the data carrier) varies with The decrease is due to the decrease, in other words, the lower This will lead to lower From equation (25), it can be deduced that in and When the values ​​are the same, the lower one This will lead to and A larger value may weaken [the effect]. and The ability to block power line carrier waves affects the resonance of the power transmission channel. In order to maintain... and The impedance to power line carrier should be increased. and The value of will result in and The increased equivalent resistance reduces power transmission efficiency. Furthermore, to simplify data recovery (achieving greater frequency separation to simplify bandpass filter (BPF) design), the data carrier frequency must be at least an order of magnitude higher than the power carrier frequency. Ultimately, 1.96 MHz was chosen as the data carrier frequency, using the 23rd harmonic of the inverter output voltage at an operating frequency of 85.2 kHz for data transmission.

[0157] Figure 12 shows the experimental waveforms of the data transmission channel. Figure 12(a) and Figure 12(b) show the waveforms of the data transmission channel during forward and reverse data transmission, respectively. As can be seen from Figure 12, the voltage amplitude of the inductor on the other side changes with the level of the input data, and the data can be successfully demodulated from the waveform after passing through the bandpass filter (BPF).

[0158] Figure 13 shows the relevant waveforms during forward data transmission. In Figure 13(a), the waveform of the data transmission channel is shown during forward data transmission, and in Figure 13(b), the waveform is shown when SPST1 is disconnected. The FFT results for the voltage are shown in Figure 13(c), which shows the FFT results when SPST1 is turned on. As can be seen from Figure 13, when the input data level is low... There are a large number of harmonic components in the voltage. Comparing Figure 13(b) and Figure 13(c), it can also be inferred that... The main cause of the voltage change is the amplitude of the 1.96 MHz harmonic.

[0159] Figure 14 shows the relevant waveforms during reverse data transmission. In Figure 14(a), the waveform of the data transmission channel is shown during reverse data transmission, and in Figure 14(b), the waveform is shown when SPST2 is disconnected. The FFT results for the voltage are shown in Figure 14(c), which shows the FFT results when SPST2 is turned on. Similar to forward data transmission, when the input data level... The amplitude of the 1.96 MHz harmonic of the voltage also changes, thereby enabling data transmission from the secondary side to the primary side.

[0160] Figure 15 shows the waveforms of the power transmission channel and the data transmission channel when power and data are transmitted simultaneously. Figure 15(a) shows the waveform of the power transmission channel, and Figure 15(b) shows the waveforms of the power and data transmission channels when power and data are transmitted simultaneously. From Figure 15(a), it can be seen that when the load... When the resistance is 10Ω, the output voltage of the power transmission channel is 55.6V and the output power is 309W. From Figure 15(b), it can also be inferred that data can be successfully demodulated while simultaneously transmitting power.

[0161] When the switch is open, the voltage stress measured on the corresponding single-pole single-throw (SPST1) and single-pole single-throw (SPST2) switches is shown in Figure 16. In Figure 16(a), the voltage stress of the single-pole single-throw (SPST1) switch is shown, and in Figure 16(b), the voltage stress measured on the single-pole single-throw (SPST2) switch is shown. Comparing Figures 10 and 16, it can be inferred that the voltage stress of the switch is very close to the theoretical analysis result, and the peak value of the voltage stress is much smaller than the rated voltage of the switch.

[0162] In summary, this embodiment proposes a harmonic modulation-based rotating structure wireless power and data transmission synchronization system. This system utilizes the harmonics of the power transmission channel as data carriers, transmitting data simultaneously during power transmission using the same coupler. This eliminates the need for a data carrier generation module, a crucial component in traditional SWPDT systems, simplifying the SWPDT system and reducing costs. For rotating applications employing SN-compensated topology, in addition to the fundamental frequency, numerous higher-order harmonic components exist on the coupling coils, which can be used for data transmission. By changing the compensation network on one side, the amplitude of a certain harmonic voltage on the other side can be adjusted. Furthermore, by detecting the harmonic amplitude, the transmitted data is demodulated, thereby achieving wireless data transmission between the two sides of the wireless power transmission system. Experimental results verify the feasibility and effectiveness of the proposed system.

[0163] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A wireless power and data synchronization transmission system based on harmonic modulation rotating structure, characterized in that: Includes a primary side and a secondary side for the rotating structure, the primary side including a DC voltage source. Full-bridge inverter, primary coil Connected to the output terminal and primary coil of the full-bridge inverter. Power transfer compensation capacitor between one end And connected to the other output terminal and primary coil of the full-bridge inverter. The primary signal circuit is located at the other end; the secondary side includes a secondary coil. Secondary signal circuit, rectifier and load resistor The primary signal circuit includes components connected in parallel to the other output terminal of the full-bridge inverter and the primary coil. The other end includes a primary LC series network and a primary modulation circuit, and also includes a primary demodulation circuit; the data carrier frequency of the primary modulation circuit... The operating frequency of the full-bridge inverter of double, The harmonic order of the full-bridge inverter output voltage selected for data transmission; the primary demodulation circuit acquires the inductance in the primary LC series network. The voltage is demodulated; the secondary signal circuit adopts a structure symmetrical to the primary signal circuit, and a parallel secondary harmonic short-circuit capacitor is added before the rectifier. 。 2. The wireless power and data synchronization transmission system based on harmonic modulation rotating structure according to claim 1, characterized in that: The secondary signal circuit, excluding the secondary harmonic short-circuit capacitor In addition, it also includes parallel connection to the secondary coil. A secondary LC series network and a secondary modulation circuit are connected between one end of the rectifier and one end of the secondary LC series network, and a secondary demodulation circuit is also included; the secondary demodulation circuit acquires the inductance in the secondary LC series network. The voltage is demodulated; the data carrier frequency of the secondary modulation circuit is the same as that of the primary modulation circuit.

3. The wireless power and data synchronization transmission system based on harmonic modulation rotating structure according to claim 2, characterized in that: The primary modulation circuit includes a data capacitor connected in series. The secondary modulation circuit includes a switch SPST1, and a data capacitor connected in series. 。 4. The wireless power and data synchronization transmission system based on harmonic modulation rotating structure according to claim 3, characterized in that: The primary LC series network includes inductors connected in series. and capacitor The secondary LC series network includes capacitors connected in series. and inductor 。 5. The wireless power and data synchronization transmission system based on harmonic modulation rotating structure according to claim 4, characterized in that: When data needs to be transmitted from the primary side to the secondary side in a forward manner, control switch SPST2 remains on, and the switching frequency of switch SPST1 between on and off is [missing information]. When data needs to be transmitted in reverse from the secondary side to the primary side, control switch SPST1 remains on, and switch SPST2 switches between on and off at a frequency of [frequency missing]. 。 6. The wireless power and data synchronization transmission system based on harmonic modulation rotating structure according to claim 5, characterized in that: The primary demodulation circuit and the secondary demodulation circuit use the same data demodulation module, which includes a bandpass filter, an envelope detector, a hysteresis voltage comparator, and an inductor. voltage or inductance The voltage input is filtered by the bandpass filter and then input to the envelope detector to extract the envelope. The hysteresis voltage comparator is used to shape the envelope into a square wave to obtain the data signal.

7. The rotary structure wireless power and data synchronization transmission system based on harmonic modulation according to any one of claims 4 to 6, characterized in that: ， ， ,as well as ， 、 These are the equivalent on-resistances of switches SPST1 and SPST2, respectively.

8. The wireless power and data synchronization transmission system based on harmonic modulation rotating structure according to claim 7, characterized in that: ， Is with The corresponding angular frequency; ， For leakage inductance reflected to the primary side, Primary coil With secondary coil Mutual attraction between them.

9. The wireless power and data synchronization transmission system based on harmonic modulation rotating structure according to claim 8, characterized in that: ， for and The center frequency.

10. The wireless power and data synchronization transmission system based on harmonic modulation rotating structure according to claim 9, characterized in that, The system parameter design process includes the following steps: S1, Determine the power carrier frequency based on the transmission power and application. and the dimensions and parameters of the coupling mechanism. 、 ； S2, according to Calculate capacitance The value of S3; determine a set of series network inductors. and The value of S4; according to Calculate capacitance and The value; S5, Determine and If the impact of internal resistance on transmission efficiency is less than the efficiency threshold, proceed to the next step; otherwise, return to step S3 and re-determine a set of series network inductors. and The value of S6; Determine and center frequency S7, according to Calculate capacitance and The value of S8; Determine and S9. Determine the maximum gain frequency point based on the transfer function and amplitude-frequency diagram of the forward and reverse data transmission channels, respectively, to determine if the impedance of the fundamental frequency of the electrical energy is greater than the impedance threshold. S10. Determine the maximum gain frequency. Is it a high-order harmonic of the inverter output? If yes, proceed to the next step; otherwise, return to step S6. S11: Determine the maximum gain frequency. Is it more important than the frequency of electric power carrier waves? At least an order of magnitude higher, or if so, based on the current... This is the data carrier frequency.

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