A design method of double-frequency wideband impedance matching network for composite Tonpilz transducer

Abstract

This invention proposes a design method for a dual-band broadband impedance matching network for a composite Tonpilz transducer, comprising: establishing an equivalent circuit model characterizing the impedance characteristics of the transducer in a first and second target frequency band based on the physical structure and material parameters of the Tonpilz transducer; constructing a dual-passband matching network topology composed of a cascaded Π-type network and a T-type network, and combining this topology with the equivalent circuit model to obtain the system impedance function; and using an adaptive Gauss-Newton algorithm with dynamic weight coefficients for convergence control to solve for the matching network element parameters in the system impedance function to obtain the element parameter combination that enables the Tonpilz transducer to achieve impedance matching simultaneously in the two target frequency bands, thus constructing a dual-band broadband impedance matching network. This method enables simultaneous impedance matching of the transducer in two target frequency bands, significantly improving the transducer's transmit voltage response, active power, and effective bandwidth, and enhancing the quality of the transmitted signal.

Description

Technical Field

[0001] This invention relates to the fields of computer vision, digital image processing and multimedia security technology, and in particular to a method for detecting local copying of images based on perceptual hashing. Background Technology

[0002] Underwater acoustic transducers are key technological equipment in marine exploration and engineering, and their performance directly determines the quality of underwater acoustic detection. The "Tonpilz" type acoustic transducer has the advantages of high power, stable performance, easy arraying, small size and high sensitivity, and is widely used in underwater communication, underwater positioning and navigation, marine resource assessment, underwater drone search and rescue and other fields.

[0003] Most Tonpilz-type piezoelectric transducers are capacitive loads, typically exhibiting multiple resonant frequencies and significant impedance fluctuations. Their impedance characteristics are characterized by multiple resonant frequencies and severe fluctuations. Particularly for practical engineering Tonpilz transducers with complex designs, such as composite filler structures, their impedance characteristics are difficult to express using specific analytical functions, leading to unclear frequency response patterns between the excitation signal and the matching network topology. Furthermore, convergence is challenging when calculating multi-component parameters. These factors constitute key bottlenecks limiting the transducer's ability to achieve efficient power output across dual frequency bands.

[0004] Transducer impedance matching is mainly divided into two categories: acoustic matching and electrical matching. In terms of acoustic material matching, coupling materials are typically added to make the transducer's radiating surface impedance close to the dielectric impedance, thereby obtaining better radiation characteristics. However, this method increases the external size of the transducer, making installation in confined spaces difficult. Furthermore, it is difficult to make rapid adjustments when the external medium changes, thus reducing the flexibility of the application scenario. Electrical matching is achieved by adding a matching network at the circuit end. However, current electrical matching design methods often focus on narrowband matching for a single resonant peak or fail to fully consider the actual composite electrical and acoustic characteristics of the transducer. Current Tonpilz transducers are mostly composite structures, and conventional circuit models can no longer characterize their admittance characteristics. Moreover, current electrical impedance matching design methods fail to consider the actual electrical and acoustic characteristics of the transducer, making it difficult to propose effective broadband matching network design methods for dual-band or multi-band problems, resulting in limited active power improvement and poor sound field radiation characteristics.

[0005] Furthermore, when performing multi-component parameter calculations for dual-band matching networks, traditional optimization algorithms often face difficulties in convergence or slow convergence speed due to the complexity of the objective function and the existence of multiple local optima. This constitutes a key bottleneck that limits the transducer from achieving efficient power output in dual-band applications. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned defects and provide a design method for a dual-frequency broadband impedance matching network for Tonpilz transducers, which can simultaneously achieve broadband impedance matching for two target frequency bands, significantly improve active power and transmit voltage response, and also has filtering characteristics.

[0007] To achieve the above objectives, this invention proposes a design method for a dual-frequency broadband impedance matching network for a composite Tonpilz transducer, comprising: Based on the physical structure and material parameters of the composite Tonpilz transducer to be matched, an equivalent circuit model characterizing the impedance characteristics of the transducer in the first and second target frequency bands is established. Construct a dual-passband matched network topology consisting of a cascaded Π-type network and a T-type network, and combine the dual-passband matched network topology with the equivalent circuit model to obtain the system impedance function; An adaptive Gauss-Newton algorithm is used to solve for the matching network element parameters in the system impedance function, and dynamic weight coefficients are introduced during the solution process for convergence control, so as to obtain the element parameter combination that enables the Tonpilz transducer to achieve impedance matching in both the first and second target frequency bands. Based on the obtained component parameter combination, the dual-frequency broadband impedance matching network is constructed.

[0008] Furthermore, the equivalent circuit model is a KLM equivalent circuit model, which equates each component structure of the Tonpilz transducer to a T-type or Π-type impedance network. The component structure includes at least: a front mass block, a piezoelectric crystal stack, a radiating head, and a composite filling structure.

[0009] Furthermore, the characteristic is that, in the KLM equivalent circuit model: The equivalent impedance network of the front mass consists of the parallel arm impedance Z 11 Z 12 and series arm impedance Z 13 Composition, in which Z 11 =Z 12 =jρ0c0A0tan(k0l0 / 2) Formula 1; Z 13 =(ρ0c0A0) / (jsin(k0l0)) Formula 2; In Formula 1-2, Z 11 Z 12 Z 13 Let be the equivalent impedance of the front mass block of the transducer; ρ0, c0, k0, A0, and l0 are the density, sound velocity, wave number, cross-sectional area, and thickness of the front mass block 1, respectively.

[0010] The equivalent impedance network of the piezoelectric crystal stack consists of the parallel arm impedance Z 21 Z 22 and series arm impedance Z 23 Composition, where Z 21 =Z 22 =jρ2c2A2tan((pk2l2) / 2) Formula 3; Z 23 =(ρ2c2A2) / (jsin(pk2l2)) Formula 4; In formula 3-4, Z 21 Z 22 Z 23 Let be the equivalent impedance of the piezoelectric crystal stack, where ρ2, c2, A2, and k2 are the density, sound velocity, cross-sectional area, and wave number of the piezoelectric ceramic, respectively.

[0011] The equivalent impedance network of the radiating head is composed of Z 31 Z 32 Z 33 The composition, whose expression includes correction terms to describe the variation in the cross-sectional area of ​​the frustum structure: Formula 5; Formula 6; Formula 7; In formula 5-7, Z 31 Z 32 Z 33 ρ1, c1, k1, A1, A3, and l1 are the equivalent impedance of the radiating head structure, and ρ1, c1, k1, A1, A3, and l1 are its density, sound velocity, wave number, upper base area of ​​the frustum structure, lower base area of ​​the frustum structure, and thickness, respectively.

[0012] The equivalent impedance network of the composite filled structure is composed of Z k1 Z k2 Z k3 Its composition, whose expression includes modification terms to describe its frustum structure: Formula 8; Formula 9; Formula 10; In Formula 8-10, Z k1 Z k2 Z k3 Let ρ3, c3, A4, A5, l3, and k2 be the equivalent impedance of the composite filling structure, and let ρ3, c3, A4, A5, l3, and k2 be its density, sound velocity, upper base area, lower base area, thickness, and wavenumber, respectively.

[0013] The equivalent impedance of the external environmental load of the transducer is: Formula 11; In Formula 11, Z R Let ρ4 be the load impedance of the external environment of the transducer, and let ρ4, c4, A1, J1, and Y1 be the density, sound velocity, contact area, and Bessel function of the first kind, respectively.

[0014] Furthermore, the dual-passband matching network topology is composed of a Π-type network and a T-type network connected in series, wherein: The Π-shaped network includes a first capacitor C. p0 First inductor L s0 Second inductor L p0 ; The T-shaped network includes a second capacitor C. p1 Third inductor L s1 and the fourth inductor L p1 ; The first capacitor C p0 One end is connected to the first inductor L s0 One end of the first inductor L is connected to and grounded. s0 The other end is connected to the second inductor L p0 One end is connected, the second inductor L p0 The other end is grounded; The third inductor L s1 One end is connected to the second inductor L p0 Connected, the first capacitor C p0 One end is connected to the third inductor L s1 One end is connected, the first capacitor C p0 The other end is grounded, and the fourth inductor L p1 One end is connected to the second capacitor C p1 Connected, fourth inductor L p1 The other end is grounded.

[0015] Furthermore, by combining the matching network topology with the KKLM equivalent circuit model, the matching network element parameters C can be obtained. p0 L s0 L p0 L s1 C p1 L p1 The system impedance function is a variable, as shown in Equation 12: Formula 12; In Equation 12, Z T The output impedance of the equivalent circuit model is obtained by integrating formula 1-11.

[0016] Furthermore, the method of introducing dynamic weight coefficients for convergence control is as follows: during the algorithm iteration process, dynamic weight coefficients are generated and allocated based on two different mathematical expectations of the impedance characteristics within the target frequency band, so as to adaptively adjust the solution path.

[0017] Furthermore, the dynamic weighting coefficients generated based on the mathematical expectation of the impedance characteristics within the target frequency band are achieved by fitting two sets of mathematical expectation values ​​through linear regression; the two sets of mathematical expectations are 0.2 and 0.1, respectively.

[0018] Furthermore, the solution process further includes: Track the extreme values ​​of the average impedance within the target frequency band and calculate the ratio of the maximum to the minimum impedance within that frequency band; When the ratio is less than a preset threshold, the algorithm determines that the component parameter combination has converged and outputs the result; otherwise, the dynamic weight coefficient is adjusted and the iteration continues.

[0019] Furthermore, the preset threshold is 0.4.

[0020] The present invention also proposes a Tonpilz transducer device, including a transducer body and an impedance matching network electrically connected thereto, wherein the impedance matching network is obtained by the above-described design method.

[0021] The present invention also proposes an underwater acoustic system, including a signal source, a power amplifier, and a Tonpilz transducer, wherein the Tonpilz transducer is the aforementioned Tonpilz transducer device.

[0022] Compared with the prior art, the advantages of the present invention are: This invention establishes a dual-passband matching network topology consisting of a Π-type network and a T-type network connected in series. This allows for the simultaneous formation of passband responses in both low-frequency and high-frequency target operating frequency bands, overcoming the limitation of traditional matching methods that can only perform narrowband matching for a single frequency band. It achieves dual-band synchronous broadband impedance matching, significantly enhancing the transducer's electroacoustic conversion efficiency and broadband operating capability.

[0023] This invention constructs a novel KLM equivalent circuit model for the Tonpilz transducer, a practical engineering transducer comprising a frustum-shaped radiating head and a composite filling structure. This model incorporates the geometric and material parameters of each composite structure of the transducer into the equivalent impedance expression, enabling precise characterization of its admittance characteristics at different frequency bands. This improves the accuracy of matching network design and provides a reliable basis for the subsequent precise design of the matching network, overcoming the shortcomings of traditional simplified models in representing composite structures.

[0024] This invention improves upon the traditional Gauss-Newton algorithm in solving the parameters of the matching network components by introducing dynamic weight coefficients based on the target frequency band impedance characteristics for adaptive convergence control. This improvement effectively avoids the problem of the algorithm getting trapped in local optima in a multi-objective, strongly nonlinear optimization space, significantly improving the convergence speed and stability of the solution, and ensuring the reliability and efficiency of the dual-band matching network parameter calculation.

[0025] The cascaded Π-type and T-type network topology used in this invention inherently possesses bandpass filtering characteristics. While achieving impedance matching, this network effectively suppresses out-of-band interference signals and spurious oscillations. Experimental tests show that the excitation voltage signal waveform after passing through the matching network is smooth, and trailing interference is effectively suppressed, thereby improving the purity of the transmitted signal and the detection performance of the entire underwater acoustic system.

[0026] This invention first establishes an equivalent KLM circuit for a composite Tonpilz transducer used in practical engineering applications. Based on this equivalent circuit, a dual-passband impedance matching network is introduced. Finally, the network element parameters are calculated using an adaptive Gauss-Newton algorithm. This dual-band broadband impedance matching network enables simultaneous impedance matching of the transducer in two target frequency bands. Its average transmit voltage response, effective bandwidth, and active power are all significantly improved. From the signal received by the hydrophone after impedance matching, the transducer's main frequency output is more concentrated and exhibits a certain filtering effect. Therefore, this method can suppress interference signals and effectively enhance the acoustic field radiation characteristics of the underwater acoustic transducer. Furthermore, this method requires no structural modifications to the transducer body or the addition of an acoustic matching layer. Therefore, this method does not increase the transducer's size and weight, making it particularly suitable for underwater instrument platforms with strict space constraints. Simultaneously, this method can be customized based on the specific parameters of different transducers, exhibiting good versatility and engineering practicality. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a Tonpilz transducer according to an embodiment of the present invention.

[0028] Figure 2 This is a diagram of the novel KLM equivalent circuit of the Tonpilz transducer established in this embodiment of the invention.

[0029] Figure 3 This is a flowchart of the calculation process of the adaptive Gauss-Newton algorithm used in this embodiment of the invention.

[0030] Figure 4 This is a comparison chart of the test results of active power in an embodiment of the present invention.

[0031] Figure 5 This is a comparison chart of the test results of the transmission voltage response in an embodiment of the present invention.

[0032] Figure 6 This is a comparison chart of the test results of the excitation signal in an embodiment of the present invention.

[0033] Figure 1 In the middle, 1-front mass block, 2-combination bolt, 3-piezoelectric ceramic stack, 4-epoxy resin, 5-radiating head, 6-filling structure, 7-cover plate, 8-cover plate bolt Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be further described below.

[0035] Example 1 This embodiment proposes a design method for a dual-frequency broadband impedance matching network for a composite Tonpilz transducer. The specific steps of this method are as follows: S1: Determine the physical parameters of the target transducer and establish the KLM equivalent circuit model.

[0036] The selected composite Tonpilz transducer has the following structure: Figure 1 As shown, it mainly consists of a front mass block 1, a piezoelectric ceramic stack 3, epoxy resin 4, combination bolts 2, a radiating head 5, and a composite filling structure 6. Specific material and dimensional parameters are as follows: the front mass block 1 is made of 45# steel, with an inner diameter of 10mm, an outer diameter of 15mm, and a height of 8mm; the piezoelectric ceramic stack 3 consists of four piezoelectric ceramic pieces made of PZT-5 material, with an inner diameter of 6mm, an outer diameter of 8mm, and a thickness of 2mm; the radiating head 5 is made of hard aluminum, with an upper base radius of 22mm, a lower base radius of 40mm, and a thickness of 8mm; the composite filling structure is made of 45# steel, with an upper base radius of 18mm, a lower base radius of 20mm, and a thickness of 5mm. The transducer operates in water, and the external load is water.

[0037] Based on the above physical structure and material parameters, a KLM equivalent circuit model of the transducer is established, as follows: Figure 2 As shown. This model equates each component of the Tonpilz transducer to a T-type or Π-type impedance network: In this embodiment, the equivalent impedance network of the front mass block 1 is composed of the parallel arm impedance Z 11 Z 12 and series arm impedance Z 13 The first T-shaped network is formed, wherein: Z 11 =Z 12 =jρ0c0A0tan(k0l0 / 2) Formula 1; Z 13 =(ρ0c0A0) / (jsin(k0l0)) Formula 2; In Formula 1-2, Z 11 Z 12 Z 13 Z is the equivalent impedance of the mass block in front of the transducer. The three are connected in a T-shape, where Z... 11 Z 12 The numerical values ​​are equal, Z 13 Numerical reference formula 2, Z 11 Located on the left side of the T-shaped structure, Z 12 Located on the right side of the T-shaped structure, Z 13 Located in the middle of the T-shaped structure; ρ0, c0, k0, A0, and l0 are the density, sound velocity, wave number, cross-sectional area, and thickness of the front mass block 1, respectively.

[0038] In this embodiment, the equivalent impedance network of the piezoelectric crystal stack (piezoelectric ceramic stack 3) is composed of parallel arm impedance Z. 21 Z 22 and series arm impedance Z 23 The second T-shaped network is formed, where: Z 21 =Z 22 =jρ2c2A2tan((pk2l2) / 2) Formula 3; Z 23 =(ρ2c2A2) / (jsin(pk2l2)) Formula 4; In formula 3-4, Z 21 Z 22 Z 23 Z is the equivalent impedance of the piezoelectric crystal stack, where Z 21 Z 22 Z 23 The three components form a T-connection, constituting the equivalent circuit impedance of the piezoelectric crystal stack, Z. 21 Z 22 The numerical values ​​are equal, Z 23 Numerical reference formula 4, Z 21 Located on the left side of the T-shaped structure, Z 22 Located on the right side of the T-shaped structure, Z 23 Located in the middle of the T-shaped structure; ρ2, c2, A2, and k2 are the density, sound velocity, cross-sectional area, and wave number of the piezoelectric ceramic, respectively.

[0039] In this embodiment, the radiating head 5 and the composite filling structure 6 are both equivalent to Z 31 Z 32 Z 33 Z k1 Z k2 Z k3 The resulting composite impedance network has impedance values ​​given by formulas 5 to 10, which include the corresponding structural dimensions. The equivalent impedance network of radiating head 5 is composed of Z31 Z 32 Z 33 The composition, whose expression includes correction terms to describe the variation in the cross-sectional area of ​​the frustum structure: Formula 5; Formula 6; Formula 7; In formula 5-7, Z 31 Z 32 Z 33 It is the equivalent impedance of the radiating head structure, where Z 31 Z 32 Z 33 For T-type connection, Z 31 Located on the left side of the T-shaped structure, Z 32 Located on the right side of the T-shaped structure, Z 33 Located in the middle of the T-shaped structure; ρ1, c1, k1, A1, A3, l1 are its density, sound velocity, wave number, upper base area of ​​the frustum structure, lower base area of ​​the frustum structure, and thickness, respectively.

[0040] The equivalent impedance network of composite filled structure 6 is composed of Z k1 Z k2 Z k3 Its composition, whose expression includes modification terms to describe its frustum structure: Formula 8; Formula 9; Formula 10; In Formula 8-10, Z k1 Z k2 Z k3 Z is the equivalent impedance of the composite filled structure. k1 Z k2 Z k3 respectively with Z 31 Z 32 Z 33 Parallel; ρ3, c3, A4, A5, l3, k2 are their density, sound velocity, upper base area, lower base area, thickness, and wave number.

[0041] The equivalent impedance of the external environmental water load of the transducer is: Formula 11; In Formula 11, Z R Let ρ4 be the load impedance of the external environment of the transducer, and let ρ4, c4, A1, J1, and Y1 be the density, sound velocity, contact area, and Bessel function of the first kind, respectively.

[0042] By integrating the above impedances, the equivalent circuit output impedance Z, which characterizes the impedance characteristics of the transducer in the target frequency band, can be obtained. T .

[0043] S2: Construct the matching network topology and generate the system impedance function.

[0044] like Figure 2 As shown in the left-hand section, a dual-passband impedance matching network topology is provided, consisting of a cascaded Π-type network and a T-type network. This matching network is connected in series with the internal resistance R of the excitation source. g The connection between the transducer and its equivalent circuit is as follows: The dual-passband matching network topology is composed of a Π-shaped network and a T-shaped network connected in series: The Π-type network includes a first capacitor C p0 First inductor L s0 Second inductor L p0 Among them, the first capacitor C p0 One end is connected to the first inductor L s0 One end is connected to the first capacitor C. p0 The other end is grounded, and the first inductor L s0 The other end is connected to the second inductor L p0 One end is connected, the second inductor L p0 The other end is grounded; The T-shaped network includes a second capacitor C. p1 Third inductor L s1 and the fourth inductor L p1 ,in, Third inductor L s1 One end is connected to the second inductor L p0 Connected, the first capacitor C p0 One end is connected to the third inductor L s1 One end is connected, the first capacitor C p0 The other end is grounded, and the fourth inductor L p1 One end is connected to the second capacitor C p1 Connected, fourth inductor L p1 The other end is grounded.

[0045] By combining the matching network topology with the KLM equivalent circuit model established in step S1, the matching network element parameters C can be obtained. p0 L s0 L p0 L s1 C p1 L p1 The system impedance function is a variable, as shown in Equation 12: Formula 12; In Equation 12, Z T The output impedance of the equivalent circuit model is obtained by integrating formula 1-11.

[0046] S3: The optimal component parameters are solved using the adaptive Gauss-Newton algorithm.

[0047] The first target operating frequency band (low frequency band) and the second target operating frequency band (high frequency band) required for the transducer are clearly defined. An improved adaptive Gauss-Newton algorithm is used to evaluate the six component parameters C in the impedance function of the above system. p0 L s0 L p0 L s1 C p1 L p1 Optimize the solution. The algorithm flow is as follows: Figure 3 As shown, its core improvement lies in the introduction of dynamic weight coefficients for convergence adaptive control. The specific steps are as follows: 1) Initialize parameters and set the target frequency band.

[0048] 2) During the algorithm iteration process, two sets of mathematical expectation values ​​(0.2 and 0.1) are fitted by linear regression to generate and allocate dynamic weight coefficients, which are used to adjust the iteration step size and direction to avoid getting trapped in local optima.

[0049] 3) Track the extreme values ​​of the average impedance within the target frequency band and calculate the ratio of the maximum to the minimum impedance within that frequency band. If the calculation results do not converge, the system will automatically adjust the dynamic weighting coefficients to continue solving.

[0050] 4) Determine if the ratio is less than the preset threshold of 0.4. If it is less, the algorithm bandwidth is deemed to meet the requirements, and the matching network element parameter combination is output; otherwise, return to step 2) to continue iteratively solving, which serves as a convergence control mechanism.

[0051] S4: Construct a matching network and conduct experimental verification.

[0052] Based on the optimal component parameter combination obtained in step S3 (i.e., C), p0 L s0 L p0 L s1 C p1 L p1 (Specific values ​​are specified), and appropriate capacitors and inductors are selected to build the actual impedance matching network according to the topology in step S2. This matching network is connected in series between the signal source and the Tonpilz transducer, and the emission performance is tested in an anechoic water tank.

[0053] The specific experimental verification results are as follows: like Figure 4As shown, the active power test results indicate that, compared to the unmatched state, after connecting the dual-band broadband impedance matching network of this embodiment, the active power of the transducer in the two target frequency bands is significantly improved, with an average increase of 1.9 times.

[0054] like Figure 5 As shown, the transmit voltage response test results indicate that the flatness of the transmit voltage response of the transducer in the two target frequency bands is significantly improved after matching, the average transmit voltage response is increased by 17.8 dB, and the effective bandwidth is increased by 1.5 times.

[0055] like Figure 6 As shown, the test results of the excitation signal indicate that the matching network effectively filters the excitation voltage signal, resulting in a smooth waveform without glitches and effectively suppressing trailing interference.

[0056] In summary, the experimental results effectively verify the effectiveness and advancement of the method proposed in this invention. This method can accurately design a dual-frequency broadband impedance matching network for composite Tonpilz transducers, significantly improving their electroacoustic performance.

[0057] Example 2 This embodiment proposes a Tonpilz transducer device, including a transducer body and an impedance matching network electrically connected thereto. The impedance matching network is obtained by the design method of the composite Tonpilz transducer dual-frequency broadband impedance matching network in Embodiment 1 above.

[0058] Example 3 This embodiment proposes an underwater acoustic system, including a signal source, a power amplifier, and a Tonpilz transducer, which is the Tonpilz transducer device of Embodiment 2 above.

[0059] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A design method for a dual-frequency broadband impedance matching network for a composite Tonpilz transducer, characterized in that, include: Based on the physical structure and material parameters of the composite Tonpilz transducer to be matched, an equivalent circuit model characterizing the impedance characteristics of the transducer in the first and second target frequency bands is established. Construct a dual-passband matched network topology consisting of a cascaded Π-type network and a T-type network, and combine the dual-passband matched network topology with the equivalent circuit model to obtain the system impedance function; An adaptive Gauss-Newton algorithm is used to solve for the matching network element parameters in the system impedance function, and dynamic weight coefficients are introduced during the solution process for convergence control, so as to obtain the element parameter combination that enables the Tonpilz transducer to achieve impedance matching in both the first and second target frequency bands. Based on the obtained component parameter combination, the dual-frequency broadband impedance matching network is constructed.

2. The design method for a dual-frequency broadband impedance matching network of a composite Tonpilz transducer according to claim 1, characterized in that, The equivalent circuit model is the KLM equivalent circuit model, which equates each component of the Tonpilz transducer to a T-type or Π-type impedance network. The component structure includes at least: a front mass block, a piezoelectric crystal stack, a radiating head, and a composite filling structure.

3. The design method for a dual-frequency broadband impedance matching network of a composite Tonpilz transducer according to claim 2, characterized in that, In the KLM equivalent circuit model: The equivalent impedance network of the front mass consists of the parallel arm impedance Z 11 Z 12 and series arm impedance Z 13 Composition, in which Z 11 =Z 12 =jρ0c0A0tan(k0l0 / 2), Z 13 =(ρ0c0A0) / (jsin(k0l0)); In the formula, Z 11 Z 12 Z 13 Let be the equivalent impedance of the front mass block of the transducer; ρ0, c0, k0, A0, and l0 are the density, sound velocity, wave number, cross-sectional area, and thickness of the front mass block 1, respectively. The equivalent impedance network of the piezoelectric crystal stack consists of the parallel arm impedance Z 21 Z 22 and series arm impedance Z 23 Composition, where Z 21 =Z 22 =jρ2c2A2tan((pk2l2) / 2), Z 23 =(ρ2c2A2) / (jsin(pk2l2)); In the formula, Z 21 Z 22 Z 23 Let ρ2 be the equivalent impedance of the piezoelectric crystal stack, where ρ2, c2, A2, and k2 are the density, sound velocity, cross-sectional area, and wave number of the piezoelectric ceramic, respectively. The equivalent impedance network of the radiating head is composed of Z 31 Z 32 Z 33 The composition, whose expression includes correction terms to describe the variation in the cross-sectional area of ​​the frustum structure: ； ； ； In the formula, Z 31 Z 32 Z 33 ρ1, c1, k1, A1, A3, and l1 are the equivalent impedance of the radiating head structure, and ρ1, c1, k1, A1, A3, and l1 are its density, sound velocity, wave number, upper base area of ​​the frustum structure, lower base area of ​​the frustum structure, and thickness, respectively. The equivalent impedance network of the composite filled structure is composed of Z k1 Z k2 Z k3 Its composition, whose expression includes modification terms to describe its frustum structure: ； ； ； In the formula, Z k1 Z k2 Z k3 Let ρ3, c3, A4, A5, l3, and k2 be the equivalent impedance of the composite filling structure, and let ρ3, c3, A4, A5, l3, and k2 be its density, sound velocity, upper base area, lower base area, thickness, and wave number, respectively. The equivalent impedance of the external environmental load of the transducer is: ； In the formula, Z R Let ρ4 be the load impedance of the external environment of the transducer, and let ρ4, c4, A1, J1, and Y1 be the density, sound velocity, contact area, and Bessel function of the first kind, respectively.

4. The design method for a dual-frequency broadband impedance matching network of a composite Tonpilz transducer according to claim 1, characterized in that, The dual-passband matching network topology is composed of a Π-shaped network and a T-shaped network connected in series, wherein: The Π-shaped network includes a first capacitor C. p0 First inductor L s0 Second inductor L p0 ; The T-shaped network includes a second capacitor C. p1 Third inductor L s1 and the fourth inductor L p1 ; The first capacitor C p0 One end is connected to the first inductor L s0 One end of the first inductor L is connected to and grounded. s0 The other end is connected to the second inductor L p0 One end is connected, the second inductor L p0 The other end is grounded; The third inductor L s1 One end is connected to the second inductor L p0 Connected, the first capacitor C p0 One end is connected to the third inductor L s1 One end is connected, the first capacitor C p0 The other end is grounded, and the fourth inductor L p1 One end is connected to the second capacitor C p1 Connected, fourth inductor L p1 The other end is grounded.

5. The design method for a dual-frequency broadband impedance matching network of a composite Tonpilz transducer according to claim 1, characterized in that, The method of introducing dynamic weight coefficients for convergence control is as follows: during the algorithm iteration process, dynamic weight coefficients are generated and allocated based on two different mathematical expectations of the impedance characteristics within the target frequency band, so as to adaptively adjust the solution path.

6. The design method for a dual-frequency broadband impedance matching network of a composite Tonpilz transducer according to claim 5, characterized in that, The dynamic weighting coefficients generated based on the mathematical expectation of the target frequency band impedance characteristics are achieved by fitting two sets of mathematical expectation values ​​through linear regression; the two sets of mathematical expectations are 0.2 and 0.1, respectively.

7. The design method for a dual-frequency broadband impedance matching network of a composite Tonpilz transducer according to claim 5, characterized in that, The solution process further includes: Track the extreme values ​​of the average impedance within the target frequency band and calculate the ratio of the maximum to the minimum impedance within that frequency band; When the ratio is less than a preset threshold, the algorithm determines that the component parameter combination has converged and outputs the result; otherwise, the dynamic weight coefficient is adjusted and the iteration continues.

8. The design method for a dual-frequency broadband impedance matching network of a composite Tonpilz transducer according to claim 7, characterized in that, The preset threshold is 0.

4.

9. A Tonpilz transducer device, characterized in that, It includes a transducer body and an impedance matching network electrically connected thereto, wherein the impedance matching network is obtained by the design method described in any one of claims 1-8.

10. An underwater acoustic system, characterized in that, It includes a signal source, a power amplifier, and a Tonpilz transducer, wherein the Tonpilz transducer is the Tonpilz transducer device as described in claim 9.

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