Electric field coupling type wireless signal transmission system suitable for rotary steering system

Abstract

This invention relates to the field of wireless signal transmission technology, specifically disclosing an electric field-coupled wireless signal transmission system suitable for rotary guidance systems, comprising a first end and a second end; the first end includes a first-end host computer, a first signal modulation and demodulation circuit, a first signal transmission / detection circuit, a first resonant network, and a first metal electrode P connected in sequence. 1 The second end includes a second metal electrode P connected in sequence. 2 The system comprises a second signal receiving / detection circuit, a second signal modulation / demodulation circuit, and a second host computer. Half-duplex communication is performed between the first and second terminals. This invention uses a pair of metal plates for signal transmission via electric field coupling. When a metal obstacle exists between the metal plates, the load resistance is adjusted to amplify the amplitude of the second received signal, improve the signal-to-noise ratio, and enhance the signal's ability to penetrate metal obstacles, thus achieving signal transmission through metal barriers.

Description

Electric field coupling wireless signal transmission system suitable for rotary guidance systems Technical Field

[0001] This invention relates to the field of wireless signal transmission technology, and in particular to an electric field-coupled wireless signal transmission system suitable for rotary guidance systems. Background Technology

[0002] In downhole rotary steering systems, there is a need for signal transmission through metal. However, traditional magnetically-coupled wireless power transfer (MCFT) technology cannot penetrate metal for signal transmission because the magnetic field is shielded by the metal. Therefore, electric-field coupled wireless power transfer (EC-WPT) technology is needed, which uses a high-frequency electric field as the energy transmission medium to achieve power transmission without direct electrical connection. Currently, mainstream EC-WPT systems use a bipolar coupling mechanism with two pairs of opposing energy plates to achieve signal transmission, meaning four energy plates can transmit power and signal simultaneously. However, the traditional four-plate coupling mechanism has some drawbacks in rotary steering applications: for example, rotary steering equipment requires flexibility, and the four-plate coupling mechanism has poor flexibility; when a metal obstacle crosses the coupling zone of two pairs of coupling plates, the system struggles to transmit signals through the metal obstacle. Summary of the Invention

[0003] This invention provides an electric field-coupled wireless signal transmission system suitable for rotary guidance systems, and solves the technical problem of how to transmit signals when there are metal obstacles in the wireless transmission gap.

[0004] To solve the above technical problems, the present invention provides an electric field-coupled wireless signal transmission system suitable for rotary guidance systems, including a first end and a second end; the first end includes a first-end host computer, a first signal modulation and demodulation circuit, a first signal transmission / detection circuit, a first resonant network, and a first metal plate P1 connected in sequence; the second end includes a second metal plate P2, a second signal reception / detection circuit, a second signal modulation and demodulation circuit, and a second host computer connected in sequence.

[0005] Half-duplex communication is performed between the first end and the second end, including:

[0006] The first end serves as a signal transmitter, and the second end serves as a signal receiver. The first end transmits a signal to the second end. At this time, the first signal modulation and demodulation circuit modulates the signal, and the first signal transmitting / detecting circuit transmits the modulated signal. The second signal receiving / detecting circuit receives the signal, and the second signal modulation and demodulation circuit demodulates the signal.

[0007] The second end serves as the signal transmitting end, and the first end serves as the signal receiving end. The second end transmits a signal to the first end. At this time, the second signal modulation and demodulation circuit modulates the signal, and the second signal transmitting / detecting circuit transmits the modulated signal. The first signal receiving / detecting circuit receives the signal, and the first signal modulation and demodulation circuit demodulates the signal.

[0008] Furthermore, the first resonant network includes a first inductor L connected between the two output terminals of the first signal transmitting / detecting circuit. p and the first capacitor C p The first inductor L p and the first capacitor C p The common terminal is connected to the first metal plate P1.

[0009] Furthermore, the second resonant network includes a second inductor L connected between the two input terminals of the second signal receiving / detecting circuit. s Second capacitor C s The second inductor L s and the second capacitor C s The common terminal is connected to the second metal plate P2.

[0010] Furthermore, the parameters C1, C2, C3, C4, C5, and C6 of the first metal plate P1 and the second metal plate P2 are determined according to actual application requirements. C1 is the equivalent capacitance of the first metal plate P1 and the penetrated metal S, C2 is the equivalent capacitance of the penetrated metal S and the second metal plate P2, C3 is the capacitance of the first metal plate P1 to ground, C4 and C5 are the capacitances of the penetrated metal S to ground, and C6 is the capacitance of the second metal plate P2 to ground.

[0011] Furthermore, the first inductor L p and the first capacitor C p The parameters are set according to the following steps:

[0012] The first inductor L is determined based on actual needs. p And determine the ground equivalent capacitance C7 of the first resonant network and the ground equivalent capacitance C8 of the second resonant network;

[0013] According to the resonance relationship Determine the first capacitor C p Where ω is the system's operating angular frequency, C a ′、C b ′ are all equivalent capacitances, and the equivalent relationship is as follows: G is the voltage output gain, C a C b C c All are equivalent resistances, satisfying:

[0014]

[0015] Furthermore, the second inductor L s and the second capacitor C s The parameters are set according to the following steps:

[0016] The second inductor L is determined based on actual needs. s ;

[0017] According to the resonance relationship Determine the second capacitor C s C c ′ is the equivalent capacitance, represented as:

[0018]

[0019] Furthermore, the second inductor L s and the second capacitor C s The parameters are respectively set to be the same as those of the first inductor L. p and the first capacitor C p Consistent.

[0020] Furthermore, the equivalent load R is adjusted in the second signal modulation and demodulation circuit according to the demodulation amplitude. eq The specific steps include:

[0021] Test the demodulated amplitude of the output signal;

[0022] Determine if the demodulated amplitude of the output signal is higher than the comparator's decision threshold. If so, maintain the current equivalent load R. eq Keep it unchanged; otherwise, adjust the equivalent load R. eq The demodulated amplitude of the output signal continues until it exceeds the comparator's decision threshold.

[0023] The electric field coupling wireless signal transmission system for rotary guidance systems provided by this invention uses a pair of metal plates to transmit signals through electric field coupling. When there is a metal obstacle between the metal plates, the amplitude of the second received signal is amplified by adjusting the load resistance, thereby improving the signal-to-noise ratio and enhancing the signal's ability to penetrate the metal obstacle, thus enabling signal transmission through the metal obstacle. Attached Figure Description

[0024] Figure 1 is a circuit architecture diagram of an electric field-coupled wireless signal transmission system suitable for a rotary guidance system provided in an embodiment of the present invention.

[0025] Figure 2 is a T-type equivalent circuit diagram of the system provided in an embodiment of the present invention;

[0026] Figure 3 is a π-type equivalent circuit diagram of the system provided in an embodiment of the present invention;

[0027] Figure 4 is a simplified equivalent circuit diagram of Figure 3 provided by an embodiment of the present invention;

[0028] Figure 5 is a π-type equivalent circuit diagram of the system when transmitting a signal from the first end to the second end according to an embodiment of the present invention;

[0029] Figure 6 is a flowchart of adjusting the equivalent load resistance provided in an embodiment of the present invention;

[0030] Figure 7 is a flowchart of setting system parameters provided in an embodiment of the present invention;

[0031] Figure 8 is a diagram of the input and output voltage waveforms in the experiment provided in the embodiment of the present invention;

[0032] Figure 9 is a comparison diagram of the waveforms of the transmitted and received signals from the electrode plate in the experiment provided in the embodiment of the present invention.

[0033] Figure 10 is a comparison diagram of the modulation waveform of the secondary side received signal and the waveform of the data received by the host computer in the experiment provided by the embodiment of the present invention. Detailed Implementation

[0034] 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.

[0035] To enable signal transmission even when metallic obstacles exist in the electric field coupling region, this invention provides an electric field-coupled wireless signal transmission system suitable for rotary guidance systems, comprising a first end and a second end. The first end includes a first-end host computer, a first signal modulation / demodulation circuit, a first signal transmitting / detecting circuit, a first resonant network, and a first metal plate P1, connected in sequence. The second end includes a second metal plate P2, a second signal receiving / detecting circuit, a second signal modulation / demodulation circuit, and a second host computer, connected in sequence. The metal plates P1 and P2 are separated by a metal that needs to be penetrated.

[0036] Half-duplex communication is performed between the first and second ends, including:

[0037] The first end serves as the signal transmitter, and the second end serves as the signal receiver. The first end transmits a signal to the second end. At this time, the first signal modulation and demodulation circuit modulates the signal, and the first signal transmitting / detecting circuit transmits the modulated signal. The second signal receiving / detecting circuit receives the signal, and the second signal modulation and demodulation circuit demodulates the signal.

[0038] The second end serves as the signal transmitter, and the first end serves as the signal receiver. The second end transmits the signal to the first end. At this time, the second signal modulation and demodulation circuit modulates the signal, and the second signal transmitting / detecting circuit transmits the modulated signal. The first signal receiving / detecting circuit receives the signal, and the first signal modulation and demodulation circuit demodulates the signal.

[0039] In conjunction with wireless power transmission, the first end can be on the same side as the power transmitter or on the power receiver, and the second end can be on the same side as the power receiver or on the power transmitter. That is, this invention can be applied to situations where the power transmitter transmits power unidirectionally to the power receiver, the power receiver transmits power unidirectionally to the power transmitter, or the power transmitter transmits power bidirectionally (half-duplex).

[0040] As shown in Figure 1, the first resonant network includes a first inductor L connected between the two output terminals of the first signal transmitting / detecting circuit. p and the first capacitor C p First inductor L p and the first capacitor C p The common terminal is connected to the first metal plate P1. The second resonant network includes a second inductor L connected between the two input terminals of the second signal receiving / detecting circuit. s Second capacitor C s Second inductor L s Second capacitor C s The common terminal is connected to the second metal plate P2.

[0041] Taking the transmission of a signal from the first end to the second end as an example, its equivalent circuit diagram is shown in Figure 2. In this circuit, C1 is the equivalent capacitance of the first metal plate P1 and the penetrated metal S, C2 is the equivalent capacitance of the penetrated metal S and the second metal plate P2, C3 is the capacitance of the first metal plate P1 to ground, C4 and C5 are the capacitances of the penetrated metal S to ground, C6 is the capacitance of the second metal plate P2 to ground, C7 is the equivalent capacitance of the first resonant network to ground, and C8 is the equivalent capacitance of the second resonant network to ground.

[0042] The T-connection in Figure 2 is equivalent to the π-connection in Figure 3. After simplifying the circuit diagram from Figure 2 to Figure 3, the following relationship exists:

[0043]

[0044] Let the output gain G = u o / u in (Output voltage / Input voltage), after simplifying the circuit diagram from Figure 3 to Figure 4, we have the following relationship:

[0045]

[0046] Assuming the signal is sent from the first to the second, the circuit diagram is shown in Figure 5.

[0047] The second-terminal load can be equivalent to a resistor R. eq R eq The calculation formula is:

[0048]

[0049] Among them, R L This is the load resistor at the second terminal.

[0050] The formula for calculating voltage gain is:

[0051]

[0052] The formula for calculating the input current is:

[0053]

[0054] Where ω is the operating angular frequency of the system, u in Let L be the input voltage. p With capacitor (C) p +C b ' / / C a ') Resonance, inductance L s With capacitor (C)s +C c ' / / C a ') Resonance, as shown in equation (6):

[0055]

[0056] The formula for calculating the output current is:

[0057]

[0058] The formula for calculating the output voltage is:

[0059] u out =G·u in (8)

[0060] As can be seen from equation (7), the output current is independent of the load; therefore, this resonant topology provides a constant current output. Thus, the equivalent load R can be adjusted in the second signal modulation / demodulation circuit according to requirements. eq (That is, by adjusting the load resistance), the amplitude of the second received signal is amplified, the signal-to-noise ratio is improved, and the ability of the signal to penetrate metal is enhanced.

[0061] Based on whether the demodulated amplitude of the signal receiving circuit meets the comparator's decision threshold, the equivalent load resistance R in the second signal modulation and demodulation circuit is adjusted. eq This allows for the adjustment of the output signal amplitude, making the high and low levels of the demodulated signal wider than the comparator's decision threshold. The specific steps are shown in Figure 6.

[0062] In practical applications, circuit parameters need to be set in advance, where the thickness of the penetrated metal plate S is d. The parameters C1, C2, C3, C4, C5, and C6 of the first metal plate P1 and the second metal plate P2 are determined according to the actual application requirements (according to the literature: LJZou, Q.Zhu, CWVan Neste and APHu, "Modeling Single-Wire Capacitive PowerTransfer System With Strong Coupling to Ground," in IEEE Journal of Emerging and Selected Topics in Power Electronics, vol.9, no.2, pp.2295-2302, April 2021.), stray capacitances C7 and C8 are determined. Then, C is determined according to equations (1) and (2). b ', C a ', C c '. First inductor L p and the first capacitor Cp The parameters are set according to the following steps:

[0063] ① First, according to equation (5), it can be seen that L p With input current i in Inversely proportional, because the current of the primary-side signal modulation circuit is limited by the PCB trace width and copper thickness, therefore L p It should not be too large; 68uH is more reasonable.

[0064] ② Determine C according to equation (6) p .

[0065] Second inductor L s Second capacitor C s The parameters are set according to the following steps:

[0066] ① First, according to equations (4) and (5), it can be seen that L s With input current i in Inversely proportional, because the current of the secondary signal modulation circuit is limited by the PCB trace width and copper thickness, therefore L s It should not be too large; 68uH is more reasonable.

[0067] ② Determine C according to equation (6) s .

[0068] When L is set p and C p Then, the resonant network L s and C s Can be set to be with L p and C p Consistent.

[0069] Therefore, all the parameters of the entire system have been set. The specific steps are as follows:

[0070] As a specific implementation example, the final settings for each parameter in this embodiment are shown in Table 1 below.

[0071] Table 1

[0072]

[0073] Based on the given parameters, a data transmission experiment was conducted in this embodiment, and the experimental setup was constructed as shown in Figure 1.

[0074] Figure 8 shows the input and output voltage waveforms. The output gain is 0.5, and according to equation (4), the gain can be adjusted by adjusting the equivalent load resistance. Figure 9 shows the input and output voltage waveforms of the signal envelope, with a gain of 1:0.5. Figure 10 shows the demodulated waveform at the second terminal and the actual data input to the microcontroller after the demodulated waveform passes through the comparator. The baud rate is 19200, indicating that the signal is transmitted with high quality.

[0075] In summary, the electric field-coupled wireless signal transmission system for rotary guidance systems provided by the embodiments of the present invention uses a pair of metal plates to transmit signals through electric field coupling. When there is a metal obstacle between the metal plates, the amplitude of the second received signal is amplified by adjusting the load resistance, thereby improving the signal-to-noise ratio and enhancing the signal's ability to penetrate metal obstacles, thus enabling signal transmission through metal obstacles.

[0076] 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. An electric field-coupled wireless signal transmission system suitable for rotary guidance systems, characterized in that, The system includes a first end and a second end. The first end includes a first-end host computer, a first signal modulation / demodulation circuit, a first signal transmitting / detecting circuit, a first resonant network, and a first metal plate P1, all connected in sequence. The second end includes a second metal plate P2, a second resonant network, a second signal receiving / detecting circuit, a second signal modulation / demodulation circuit, and a second host computer, all connected in sequence. Half-duplex communication is performed between the first end and the second end, including: the first end acting as a signal transmitter, the second end acting as a signal receiver, the first end transmitting a signal to the second end, during which the first signal modulation / demodulation circuit modulates the signal. The first signal transmitting / detecting circuit transmits the modulated signal; the second signal receiving / detecting circuit receives the signal, and the second signal modulation / demodulation circuit demodulates the signal; the second terminal acts as a signal transmitting terminal, and the first terminal acts as a signal receiving terminal. The second terminal transmits a signal to the first terminal, at which time the second signal modulation / demodulation circuit modulates the signal, and the second signal transmitting / detecting circuit transmits the modulated signal; the first signal receiving / detecting circuit receives the signal, and the first signal modulation / demodulation circuit demodulates the signal; the first resonant network includes a first inductor L connected between the two output terminals of the first signal transmitting / detecting circuit. p and the first capacitor C p The first inductor L p and the first capacitor C p The common terminal is connected to the first metal plate P1; the second resonant network includes a second inductor L connected between the two input terminals of the second signal receiving / detecting circuit. s Second capacitor C s The second inductor L s and the second capacitor C s The common terminal is connected to the second metal electrode P2; the parameters of the first metal electrode P1 and the second metal electrode P2 、 、 、 、 、 Determined based on actual application requirements. It is the equivalent capacitance of the first metal plate P1 and the penetrated metal S. It is the equivalent capacitance between the penetrated metal S and the second metal plate P2. It is the capacitance to ground of the first metal plate P1. and It is the capacitance to ground of the penetrated metal S. It is the capacitance to ground of the second metal plate P2; the first inductor L p and the first capacitor C p The parameters are set according to the following steps: Determine the first inductor L based on actual needs. p And determine the equivalent capacitance to ground C7 of the first resonant network and the equivalent capacitance to ground C8 of the second resonant network; based on the resonance relationship Determine the first capacitor C p ,in The system's operating angular frequency, 、 All are equivalent capacitances, and the equivalent relationship is as follows: ， ， For voltage output gain, 、 、 All are equivalent resistances, satisfying: The second inductor L s and the second capacitor C s The parameters are set according to the following steps: Determine the second inductor L based on actual needs. s According to the resonance relationship Determine the second capacitor C s , The equivalent capacitance is represented as: The equivalent load R is adjusted in the second signal modulation and demodulation circuit according to the demodulation amplitude. eq The specific steps include: testing the demodulated amplitude of the output signal; determining whether the demodulated amplitude of the output signal is higher than the comparator's decision threshold; if so, maintaining the current equivalent load R. eq Keep it unchanged; otherwise, adjust the equivalent load R. eq The demodulated amplitude of the output signal continues until it exceeds the comparator's decision threshold.

2. The electric field-coupled wireless signal transmission system for rotary guidance systems according to claim 1, characterized in that, The second inductor L s and the second capacitor C s The parameters are respectively set to be the same as those of the first inductor L. p and the first capacitor C p Consistent.

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