Resonant bridge arrangement based on double-differential transformer and method of building

Abstract

The present application relates to the technical field of electronic circuit, and especially relates to a resonant bridge device based on double differential transformer and a building method, two differential transformers with consistent parameters are used, a new resonant bridge is constructed by connecting the first primary winding end of the first transformer with the third primary winding end of the second transformer, connecting the second primary winding end of the first transformer with the fourth primary winding end of the second transformer, and connecting the secondary winding end of the first transformer with the secondary winding end of the second transformer. Under the condition of ensuring that the resonant frequency is unchanged, the equivalent capacitance value of the bridge is doubled compared with the single transformer scheme, so that the allowed cable length is doubled. The present application can effectively solve the problem that the resonant frequency deviates caused by the excessively long cable of the differential variable-pitch capacitance displacement sensor in the multi-degree-of-freedom application, and is suitable for high-precision measurement scenes such as gravitational wave detection which need long-distance transmission.

Description

Technical Field

[0001] This invention belongs to the field of electronic circuit technology, and particularly relates to a resonant bridge device based on a double differential transformer and its construction method. Background Technology

[0002] Differential variable-gap capacitive displacement sensors are high-precision non-contact displacement sensors. Their working principle is based on the non-linear relationship between the capacitance of a parallel-plate capacitor and the distance between the plates. These sensors offer advantages such as sub-picometer resolution, high sensitivity, and low noise, and have been widely used in cutting-edge fields such as gravitational wave detection, precision metrology, and inertial navigation.

[0003] Combination Figure 1 As shown, the sensor front-end circuit in existing technical solutions generally includes a sensitive probe, sensing electrodes, connecting cables, a differential transformer, a resonant bridge, and a transimpedance amplifier. The sensitive probe is generally connected to the front-end electronic circuit via cables. Figure 1 middle This indicates the excitation signal module, and TM indicates the test quality. This is the first sensing capacitance formed between the excitation electrode plate and the test mass. This is to create a second sensing capacitance between the excitation electrode plate and the test mass. For the first tuning capacitor, Second tuning capacitor, and To reserve adjustment capacitors, For the first primary winding inductance, For the second primary winding inductance, For the primary winding inductance, For the first decoupling capacitor, For the second decoupling capacitor, For the first feedback capacitor, For the second feedback capacitor, For the first feedback resistor, This is the second feedback resistor. Test quality typically involves multiple degrees of freedom. For example, inertial sensors used for gravitational wave detection have six degrees of freedom, requiring numerous and complex cables. These cables are also limited by spatial structures, connector locations, and cable bend radii. Currently, long cables can be used to address this issue. However, due to the inherent properties of the resonant bridge, long cables can cause the resonant bridge's resonant frequency to shift, affecting sensor performance. Therefore, to ensure sensor performance, the sensor must resonate at its operating frequency. This condition limits the maximum cable length in the circuit. The reason is that the resonant frequency is related to the product of the transformer inductance and the capacitance in the circuit. The capacitance includes stray capacitance, cable capacitance, and tuning capacitance. That is, given a fixed resonant frequency, the capacitance value is fixed, thus limiting the cable length. Summary of the Invention

[0004] In view of this, the present invention aims to provide a resonant bridge device and construction method based on a double differential transformer, which doubles the equivalent capacitance of the bridge while ensuring that the sensor operates at the resonant frequency, thereby doubling the allowable cable length and meeting the long-distance transmission requirements of multi-degree-of-freedom sensors.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows: A resonant bridge device based on a double differential transformer includes: The first differential transformer includes a first primary winding, a second primary winding, and a first primary winding. The second differential transformer includes a third primary winding, a fourth primary winding, and a second secondary winding; A connection circuit is used to connect the first end of the first primary winding to the first end of the third primary winding, to use the second end of the first primary winding and the second end of the third primary winding as the first pair of terminals of a new primary winding, to connect the first end of the second primary winding to the first end of the fourth primary winding, to use the second end of the second primary winding and the second end of the fourth primary winding as the second pair of terminals of a new primary winding, to connect the first end of the first primary winding to the first end of the second secondary winding, and to use the second end of the first primary winding and the second end of the second secondary winding as terminals of a new secondary winding. A resonant bridge circuit, connected to the new primary winding and the new secondary winding, is used to adjust to a resonant state.

[0006] Furthermore, the winding turns ratio, coupling coefficient, and quality factor parameters of the first differential transformer and the second differential transformer are consistent.

[0007] A method for constructing a resonant bridge based on a double differential transformer, using the resonant bridge device based on a double differential transformer as described above, includes: A first differential transformer and a second differential transformer are provided. The first differential transformer includes a first primary winding, a second primary winding, and a first primary winding. The first primary winding has a first terminal and a second terminal. The second primary winding has a third terminal and a fourth terminal. The first primary winding has a fifth terminal and a sixth terminal. The second differential transformer includes a third primary winding, a fourth primary winding, and a second primary winding. The third primary winding has a seventh terminal and an eighth terminal. The fourth primary winding has a ninth terminal and a tenth terminal. The second primary winding has an eleventh terminal and a twelfth terminal. Connect the first end to the seventh end, and connect the second end and the eighth end as the first pair of terminals of the new primary winding into the circuit. Connect the third terminal to the ninth terminal, and connect the fourth terminal and the tenth terminal as the second pair of terminals of the new primary winding into the circuit. Connect the fifth terminal to the eleventh terminal, and connect the sixth terminal and the twelfth terminal to the circuit as the terminals of the new secondary winding; Connect the new primary winding and the new secondary winding to a resonant bridge circuit and adjust the circuit to a resonant state.

[0008] Furthermore, the first primary winding and the second primary winding of the first differential transformer maintain symmetry, and the coupling coefficient between the first primary winding and the first and second primary windings of the first differential transformer is the same; the third primary winding and the fourth primary winding of the second differential transformer maintain symmetry, and the coupling coefficient between the second primary winding and the third and fourth primary windings of the second differential transformer is the same; and the winding parameters of the first differential transformer and the second differential transformer are the same.

[0009] Furthermore, the resonant bridge circuit also includes a tuning capacitor, stray capacitor, and cable capacitor. Under the condition that the resonant frequency remains unchanged, a double differential transformer structure is used to increase the equivalent capacitance value of the bridge to twice that of a single differential transformer structure, so that the allowable cable length is increased to twice that of a single differential transformer structure.

[0010] Compared with the prior art, the present invention can achieve the following beneficial effects: The resonant bridge device and construction method based on dual differential transformers provided in this invention utilize two differential transformers with identical parameters. A new resonant bridge is constructed by connecting the first primary winding terminal of the first transformer to the third primary winding terminal of the second transformer, the second primary winding terminal of the first transformer to the fourth primary winding terminal of the second transformer, and the secondary winding terminal of the first transformer to the secondary winding terminal of the second transformer. While maintaining the resonant frequency unchanged, the equivalent capacitance of the bridge is increased to twice that of the single-transformer scheme, thereby doubling the allowable cable length. This invention effectively solves the problem of resonant frequency shift caused by excessively long cables in multi-degree-of-freedom applications of differential variable-gap capacitive displacement sensors, and is suitable for high-precision measurement scenarios requiring long-distance transmission, such as gravitational wave detection. Attached Figure Description

[0011] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a block diagram illustrating the principle of the primary winding tuning scheme of a resonant bridge in the prior art.

[0012] Figure 2 A schematic diagram illustrating the resonant bridge construction method of the resonant bridge device based on a double differential transformer as described in an embodiment of the present invention; Figure 3 This is a schematic diagram of the differential transformer structure of the resonant bridge device based on a double differential transformer as described in an embodiment of the present invention.

[0013] Figure 4 A schematic diagram illustrating the naming of the differential transformer windings in the resonant bridge device based on a double differential transformer, as described in an embodiment of the present invention.

[0014] Explanation of reference numerals in the attached figures: The first differential transformer is 100, and the second differential transformer is 200. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0017] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0018] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] like Figure 2 As shown in the embodiment of the present invention, a resonant bridge device based on a double differential transformer includes: The first differential transformer 100 includes a first primary winding, a second primary winding and a first primary winding, wherein the first primary winding has a first terminal number 1 and a second terminal number 2, the second primary winding has a third terminal number 3 and a fourth terminal number 4, and the first primary winding has a fifth terminal number 5 and a sixth terminal number 6. The second differential transformer 200 includes a third primary winding, a fourth primary winding and a second secondary winding, wherein the third primary winding has a seventh terminal number 7 and an eighth terminal number 8, the fourth primary winding has a ninth terminal number 9 and a tenth terminal number 10, and the second secondary winding has an eleventh terminal number 11 and a twelfth terminal number 12. A connection circuit is used to connect the first end number 1 of the first primary winding to the first end number 7 of the third primary winding, to use the second end number 2 of the first primary winding and the second end number 8 of the third primary winding as the first pair of terminals of the new primary winding, to connect the first end number 3 of the second primary winding to the first end number 9 of the fourth primary winding, to use the second end number 4 of the second primary winding and the second end number 10 of the fourth primary winding as the second pair of terminals of the new primary winding, to connect the first end number 5 of the first primary winding to the first end number 11 of the second secondary winding, and to use the second end number 6 of the first secondary winding and the second end number 12 of the second secondary winding as terminals of the new secondary winding. A resonant bridge circuit, connected to the new primary winding and the new secondary winding, is used to adjust to a resonant state.

[0021] also, Figure 2 middle This indicates the excitation signal module, and TM indicates the test quality. This is the first sensing capacitance formed between the excitation electrode plate and the test mass. This is to create a second sensing capacitance between the excitation electrode plate and the test mass. For the first tuning capacitor, Second tuning capacitor, and To reserve adjustment capacitors, For the first decoupling capacitor, For the second decoupling capacitor, For the first feedback capacitor, For the second feedback capacitor, For the first feedback resistor, This is the second feedback resistor.

[0022] In some embodiments, in differential variable-gap capacitive displacement sensor applications, the symmetry of the resonant bridge affects the final measurement results. Therefore, it is necessary to ensure the symmetry of the differential transformer windings and the consistency of the two differential transformers. Thus, the winding turns ratio, coupling coefficient, and quality factor parameters of the first differential transformer 100 and the second differential transformer 200 are consistent.

[0023] In this embodiment, the two differential transformers can meet the following consistency requirements: The number of turns in the first primary winding A and B is the same, and the number of turns in the second primary winding a and b is the same. The coupling coefficient of the first primary winding C is the same as that of the first primary winding, and the coupling coefficient of the second primary winding C is the same as that of the second primary winding. The two differential transformers have the same quality factor Q value.

[0024] The resonant bridge device based on dual differential transformers provided in this embodiment of the invention uses two differential transformers with identical parameters. A new resonant bridge is constructed by connecting the first primary winding terminal of the first transformer to the third primary winding terminal of the second transformer, the second primary winding terminal of the first transformer to the fourth primary winding terminal of the second transformer, and the secondary winding terminal of the first transformer to the secondary winding terminal of the second transformer. While maintaining the resonant frequency unchanged, the equivalent capacitance of the bridge is increased to twice that of the single-transformer scheme, thereby doubling the allowable cable length. This invention effectively solves the problem of resonant frequency shift caused by excessively long cables in multi-degree-of-freedom applications of differential variable-gap capacitive displacement sensors, and is suitable for high-precision measurement scenarios requiring long-distance transmission, such as gravitational wave detection.

[0025] This can solve the problem of insufficient cable length caused by the limited tuning capacitor in a resonant bridge. It can extend the transmission cable length while ensuring the resonant bridge operates at its resonant frequency.

[0026] Combination Figure 2 , 3As shown in Figure 4, the present invention provides a method for constructing a resonant bridge based on a double differential transformer, which utilizes the resonant bridge device based on a double differential transformer as described above, and includes: S1. Provide a first differential transformer and a second differential transformer. The first differential transformer includes a first primary winding, a second primary winding, and a first primary winding. The first primary winding has a first terminal and a second terminal. The second primary winding has a third terminal and a fourth terminal. The first primary winding has a fifth terminal and a sixth terminal. The second differential transformer includes a third primary winding, a fourth primary winding, and a second primary winding. The third primary winding has a seventh terminal and an eighth terminal. The fourth primary winding has a ninth terminal and a tenth terminal. The second primary winding has an eleventh terminal and a twelfth terminal. S2. Connect the first end to the seventh end, and connect the second end and the eighth end as the first pair of terminals of the new primary winding to the circuit. S3. Connect the third end to the ninth end, and connect the fourth end and the tenth end to the circuit as the second pair of terminals of the new primary winding. S4. Connect the fifth terminal to the eleventh terminal, and connect the sixth terminal and the twelfth terminal to the circuit as the wiring terminals of the new secondary winding; S5. Connect the new primary winding and the new secondary winding to the resonant bridge circuit and adjust the circuit to the resonant state.

[0027] In some embodiments, the first primary winding and the second primary winding of the first differential transformer maintain the same number of turns, and the coupling coefficient between the first primary winding and the first primary winding and the second primary winding of the first differential transformer is the same; the third primary winding and the fourth primary winding of the second differential transformer maintain symmetry, and the coupling coefficient between the second primary winding and the third primary winding and the fourth primary winding of the second differential transformer is the same; and the winding parameters of the first differential transformer and the second differential transformer are the same.

[0028] In some embodiments, the resonant bridge circuit further includes a tuning capacitor, stray capacitor, and cable capacitor. Under the condition that the resonant frequency remains unchanged, a double differential transformer structure is used to increase the equivalent capacitance value of the bridge to twice that of a single differential transformer structure, so that the allowable cable length is increased to twice that of a single differential transformer structure.

[0029] In some embodiments, the sensor front-end circuit generally includes a sensitive probe, sensing electrodes, connecting cables, a differential transformer resonant bridge, and a transimpedance amplifier.

[0030] like Figure 3 and Figure 4As shown, to facilitate understanding of this solution, this embodiment of the invention provides an example of a resonant bridge construction method based on dual differential transformers. The first differential transformer is defined as T1, and the second differential transformer as T2. The windings can be connected in the following order: S11. Connect the first terminal 1 of the first primary winding A of T1 to the seventh terminal 7 of the third primary winding a of T2 with a wire. At this time, the first terminal 1 and the seventh terminal 7 are at the same potential.

[0031] S12, the second end 2 of the first primary winding A of T1 and the eighth end 8 of the third primary winding a of T2 are connected by a wire. S11 and S12 together serve as the first pair of terminals of the new primary winding (denoted as P1 and P1') and are connected to the excitation signal source.

[0032] S13. Connect the third terminal 3 of the second primary winding B of T1 to the ninth terminal 9 of the fourth primary winding b of T2 with a wire. At this time, the third terminal 3 and the ninth terminal 9 are at the same potential.

[0033] S14, the fourth terminal 4 of the second primary winding B of T1 and the tenth terminal 10 of the fourth primary winding b of T2 are connected by a wire. S13 and S14 together serve as the second pair of terminals of the new primary winding (denoted as P2 and P2'), and are connected to the other end of the excitation signal source.

[0034] S15. Connect the fifth terminal 5 of the primary winding C of T1 to the eleventh terminal 11 of the secondary winding C of T2 with a wire. At this time, the fifth terminal 5 and the eleventh terminal 11 are at the same potential.

[0035] S16, the sixth terminal 6 of the primary winding C of T1, and the twelfth terminal 12 of the secondary winding C of T2 are connected by wires. S15 and S16 together serve as the terminals of the new secondary winding (denoted as S1 and S2), and output differential signals to the transimpedance amplifier.

[0036] After assembly, connect to a resonant bridge circuit and tune.

[0037] Connect the new primary winding to the excitation signal source, and the new secondary winding to the transimpedance amplifier. Connect a tuning capacitor in parallel in the circuit. Ct , Ct The value of needs to approximately satisfy:

[0038] in, L eq The equivalent inductance of the new primary winding, C s Stray capacitance C cable For cable capacitors, This indicates the resonant frequency.

[0039] Principle Analysis: In the single-transformer scheme, the total bridge capacitance is: .

[0040] In the dual-transformer scheme of this invention, since the primary windings of the two transformers are connected in parallel and then connected to the circuit, and the two secondary windings are also connected in parallel and then output, the equivalent inductance is... L eq Compared to the single-transformer scheme, it becomes 1 / 2 L eq The equivalent capacitance becomes twice its original value. This is because the winding capacitance and cable capacitance of both transformers are included in the bridge circuit, assuming the resonant frequency remains constant: C cable′ =2C total =2(C t +C s +C cable ) when C cable′ =2C total =2(C t +C s +C cable ) At that time, the allowable cable capacitance C cable′ It can achieve twice the efficiency of a single transformer solution, meaning the cable length can be doubled.

[0041] The resonant bridge construction method based on a dual differential transformer provided in this invention can be applied to six-degree-of-freedom inertial sensors. In inertial sensors used for gravitational wave detection, quality testing requires displacement measurement of six degrees of freedom, necessitating a total of 12 cables (12 cables for six pairs of sensing electrodes). By adopting the dual differential transformer resonant bridge scheme of this invention, the allowable length of a single cable increases from the original L to 2L, doubling the total transmission distance capability and effectively solving the engineering problem of resonant frequency shift caused by excessively long cables in multi-degree-of-freedom systems.

[0042] The resonant bridge construction method based on dual differential transformers provided in this invention uses two differential transformers with identical parameters. A new resonant bridge is constructed by connecting the first primary winding terminal of the first transformer to the third primary winding terminal of the second transformer, the second primary winding terminal of the first transformer to the fourth primary winding terminal of the second transformer, and the secondary winding terminal of the first transformer to the secondary winding terminal of the second transformer. While maintaining the resonant frequency unchanged, the equivalent capacitance of the bridge is increased to twice that of the single-transformer scheme, thereby doubling the allowable cable length. This invention effectively solves the problem of resonant frequency shift caused by excessively long cables in multi-degree-of-freedom applications of differential variable-gap capacitive displacement sensors, and is suitable for high-precision measurement scenarios requiring long-distance transmission, such as gravitational wave detection.

[0043] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A resonant bridge device based on a double differential transformer, characterized in that, include: The first differential transformer includes a first primary winding, a second primary winding, and a first primary winding. The second differential transformer includes a third primary winding, a fourth primary winding, and a second secondary winding; A connection circuit is used to connect the first end of the first primary winding to the first end of the third primary winding, to use the second end of the first primary winding and the second end of the third primary winding as the first pair of terminals of a new primary winding, to connect the first end of the second primary winding to the first end of the fourth primary winding, to use the second end of the second primary winding and the second end of the fourth primary winding as the second pair of terminals of a new primary winding, to connect the first end of the first primary winding to the first end of the second secondary winding, and to use the second end of the first primary winding and the second end of the second secondary winding as terminals of a new secondary winding. A resonant bridge circuit, connected to the new primary winding and the new secondary winding, is used to adjust to a resonant state; The resonant bridge circuit also includes a tuning capacitor, stray capacitor, and cable capacitor. Under the condition that the resonant frequency remains unchanged, a double differential transformer structure is used to increase the equivalent capacitance value of the bridge to twice that of a single differential transformer structure, so that the allowable cable length is increased to twice that of a single differential transformer structure.

2. The resonant bridge device based on a double differential transformer according to claim 1, characterized in that, The first differential transformer and the second differential transformer have the same winding turns ratio, coupling coefficient, and quality factor parameters.

3. A method for constructing a resonant bridge based on a double differential transformer, using the resonant bridge device based on a double differential transformer as described in claim 1 or 2, characterized in that, include: A first differential transformer and a second differential transformer are provided. The first differential transformer includes a first primary winding, a second primary winding, and a first primary winding. The first primary winding has a first terminal and a second terminal. The second primary winding has a third terminal and a fourth terminal. The first primary winding has a fifth terminal and a sixth terminal. The second differential transformer includes a third primary winding, a fourth primary winding, and a second primary winding. The third primary winding has a seventh terminal and an eighth terminal. The fourth primary winding has a ninth terminal and a tenth terminal. The second primary winding has an eleventh terminal and a twelfth terminal. Connect the first end to the seventh end, and connect the second end and the eighth end as the first pair of terminals of the new primary winding into the circuit. Connect the third terminal to the ninth terminal, and connect the fourth terminal and the tenth terminal as the second pair of terminals of the new primary winding into the circuit. Connect the fifth terminal to the eleventh terminal, and connect the sixth terminal and the twelfth terminal to the circuit as the terminals of the new secondary winding; The new primary winding and the new secondary winding are connected to a resonant bridge circuit, and the circuit is adjusted to a resonant state. The resonant bridge circuit also includes a tuning capacitor, stray capacitor, and cable capacitor. Under the condition that the resonant frequency remains unchanged, a double differential transformer structure is used to increase the equivalent capacitance value of the bridge to twice that of a single differential transformer structure, so that the allowable cable length is increased to twice that of a single differential transformer structure.

4. The method for constructing a resonant bridge based on a double differential transformer according to claim 3, characterized in that, The first primary winding and the second primary winding of the first differential transformer maintain symmetry, and the coupling coefficient between the first primary winding and the first primary winding and the second primary winding of the first differential transformer is the same; the third primary winding and the fourth primary winding of the second differential transformer maintain symmetry, and the coupling coefficient between the second primary winding and the third primary winding and the fourth primary winding of the second differential transformer is the same; and the winding parameters of the first differential transformer and the second differential transformer are the same.

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