Ultrasonic tool holder resonance frequency tracking system and method based on phase positioning

Abstract

A system and method for tracking the resonant frequency of an ultrasonic scalpel based on phase positioning, the system comprising a power inverter module, a signal sampling and processing module, a microprocessor, a loosely coupled wirelessly powered ultrasonic scalpel, and an adjustable DC power supply. The resonant frequency tracking method of the present invention combines the advantages of fast search using the phase method and the precise search using the maximum current method. The ultrasonic scalpel is divided into five phase working areas using impedance and phase characteristics. Rapid phase identification is performed through the monotonic characteristics of the phase curve. After locating the phase position, the direction of the maximum current is determined, avoiding multiple judgments of the maximum current direction during the search process, and enabling rapid and accurate search of the frequency of the maximum current point. In terms of phase division and judgment, the present invention combines the results of frequency sweeps for regional division, and mainly uses the difference in monotonicity of the working area for judgment, rather than specific values. Therefore, the phase characteristic curves of various phase ranges can be applied, greatly enhancing the applicability to different ultrasonic scalpels.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultrasonic machining, and in particular relates to a system and method for tracking the resonance frequency of an ultrasonic tool holder based on phase positioning. Background Art

[0002] Ultrasonic-assisted machining is gaining popularity in machining hard and brittle materials and thin-walled parts. For example, ultrasonic milling, in which ultrasonic vibrations are added, can reduce milling forces and improve the surface quality of the workpiece.

[0003] However, the ultrasonic toolholder can shift its resonant frequency under the influence of load, causing amplitude attenuation or even failure, which can negatively impact the machined surface. Therefore, tracking the resonant frequency is crucial for ultrasonic-assisted machining.

[0004] Traditional resonant frequency tracking methods include the phase method and the maximum current method. The phase method ensures the resonant state by locking the zero phase difference between voltage and current, while the maximum current method ensures the resonant state by searching for the maximum current of the transducer (i.e., the minimum impedance point).

[0005] However, for wirelessly powered ultrasonic toolholders, the applicability of the phase and maximum current methods is significantly reduced. Specifically, the resonant phase in the impedance characteristic of the phase method is not necessarily at zero phase and can vary with load changes during the auxiliary machining process. Frequency tracking using the maximum current method is difficult in determining the tracking direction, and additional calculations are required when the resonant frequency shifts. Summary of the Invention

[0006] To address the problems of the prior art, the present invention provides a phase-based ultrasonic scalpel resonant frequency tracking system and method. This system combines the advantages of the phase method's rapid search speed with the maximum current method's precise search accuracy. The system uses impedance and phase characteristics to divide the ultrasonic scalpel into five phase working zones. Rapid phase identification is performed through the monotonic characteristics of the phase curve. After locating the phase position, the direction of the maximum current is determined, avoiding multiple judgments of the maximum current direction during the search process and enabling rapid and accurate search for the frequency of the maximum current point. In terms of phase division and judgment, the present invention combines frequency sweep results for regional division, primarily utilizing differences in the monotonicity of the working zones for judgment, rather than specific values. Therefore, the system can be applied to phase characteristic curves of various phase ranges, greatly enhancing its applicability to different ultrasonic scalpels.

[0007] In order to achieve the above-mentioned objectives, the present invention adopts the following technical solution: a phase positioning-based ultrasonic scalpel resonant frequency tracking system, comprising a power inverter module, a signal sampling and processing module, a microprocessor, a loosely coupled wireless power supply ultrasonic scalpel and an adjustable DC power supply; the current output end of the adjustable DC power supply is electrically connected to the current input end of the power inverter module, and the current output end of the power inverter module is divided into two output paths, one path is electrically connected to the loosely coupled wireless power supply ultrasonic scalpel, and the other path is electrically connected to the current input end of the signal sampling and processing module; the signal output end of the signal sampling and processing module is electrically connected to the signal input end of the microprocessor, and the signal output end of the microprocessor is electrically connected to the signal input end of the power inverter module.

[0008] The power inverter module includes a chopper circuit submodule, a full-bridge inverter circuit submodule, a power control submodule and a drive frequency control submodule; the current input end of the chopper circuit submodule is electrically connected to the current output end of the adjustable DC power supply, the current output end of the chopper circuit submodule is electrically connected to the current input end of the full-bridge inverter circuit submodule, and the current output end of the full-bridge inverter circuit submodule is divided into two output paths, one path is electrically connected to the loosely coupled wireless power supply ultrasonic knife handle, and the other path is electrically connected to the current input end of the signal sampling and processing module; the signal input end of the power control submodule is electrically connected to the signal output end of the microprocessor, and the signal output end of the power control submodule is electrically connected to the signal input end of the chopper circuit submodule; the signal input end of the drive frequency control submodule is electrically connected to the signal output end of the microprocessor, and the signal output end of the drive frequency control submodule is electrically connected to the signal input end of the full-bridge inverter circuit submodule.

[0009] The signal sampling and processing module includes a voltage sampling and filtering submodule, a phase conversion submodule, a current sampling and filtering submodule and a current effective value conversion submodule; the signal input end of the voltage sampling and filtering submodule is electrically connected to the signal output end of the full-bridge inverter circuit submodule, the signal output end of the voltage sampling and filtering submodule is electrically connected to the signal input end of the phase conversion submodule, and the signal output end of the phase conversion submodule is electrically connected to the signal input end of the microprocessor; the signal input end of the current sampling and filtering submodule is electrically connected to the signal output end of the full-bridge inverter circuit submodule, and the signal output end of the current sampling and filtering submodule is divided into two output paths, one path is electrically connected to the signal input end of the phase conversion submodule, and the other path is electrically connected to the signal input end of the current effective value conversion submodule, and the signal output end of the current effective value conversion submodule is electrically connected to the signal input end of the microprocessor.

[0010] The power inverter module is used to control and convert the frequency and power of the loosely coupled wireless powered ultrasonic scalpel handle; the signal sampling and processing module is used to perform signal sampling and processing; wherein, the voltage sampling and filtering submodule is used to sample and process the voltage signal, the current sampling and filtering submodule is used to sample and process the current signal, the phase conversion submodule is used to extract the phase difference between the voltage and the current, and the current effective value conversion submodule is used to extract the effective value of the current; the microprocessor is used to receive the phase difference signal and the current effective value signal from the signal sampling and processing module, and when the resonant frequency of the loosely coupled wireless powered ultrasonic scalpel handle shifts, it is used to issue a control instruction to the power inverter module to quickly and accurately search for the frequency of the maximum current point.

[0011] A method for tracking the resonance frequency of an ultrasonic tool handle based on phase positioning, which uses the aforementioned ultrasonic tool handle resonance frequency tracking system based on phase positioning, includes the following steps:

[0012] Step S1: Frequency sweep and impedance analysis

[0013] Perform a frequency scan on the currently working loosely coupled wireless powered ultrasonic scalpel handle, and analyze the impedance characteristics of the currently working loosely coupled wireless powered ultrasonic scalpel handle to obtain the resonant frequency and resonant phase of the currently working loosely coupled wireless powered ultrasonic scalpel handle;

[0014] Step S2: Workspace division

[0015] In the phase range near the resonant phase, the operating current is maintained near the maximum current point. According to the required resonant current operating range, the resonant frequency range is set, and five working areas A, B, C, D, and E are divided accordingly, providing a theoretical basis for the judgment in step S3;

[0016] Step S3: Working phase positioning

[0017] When the loosely coupled wireless powered ultrasonic tool handle is operating in a detuned state, the working area of ​​the current frequency is judged according to the working areas divided in step S2, and the search direction of the maximum current is determined; wherein, area B is in the resonant working area and no search is performed; the frequency of area A is lower than the frequency of the maximum current point, and the search direction is set to increase the frequency; the frequency of areas C, D, and E is higher than the frequency of the maximum current point, and the search direction is set to decrease the frequency;

[0018] Step S4: Maximum current search

[0019] According to the search direction determined in step S3, the frequency is adjusted monotonically to quickly track the maximum current point, that is, the resonant frequency.

[0020] In step S2, the five working areas A, B, C, D, and E are specifically divided as follows: Area A is the entire area on the left side of the resonance interval of the loosely coupled wireless power ultrasonic scalpel handle, far away from the resonance point; Area B is the resonance interval range of the loosely coupled wireless power ultrasonic scalpel handle, which is determined by the phase interval corresponding to the allowable resonance current interval; Area C is the area between the resonance interval and the anti-resonance interval of the loosely coupled wireless power ultrasonic scalpel handle; Area D is the anti-resonance interval corresponding to the phase value of the resonance interval of the loosely coupled wireless power ultrasonic scalpel handle; Area E is the entire area on the right side of the anti-resonance interval of the loosely coupled wireless power ultrasonic scalpel handle, far away from the anti-resonance point.

[0021] In step S3, the specific steps for working phase positioning are:

[0022] Step S301: According to the five working areas A, B, C, D, and E set in step S2, the microprocessor performs phase capture and collects the current phase difference signal phase0;

[0023] Step S302: Distinguish between AE, BD, and C zones through a judgment statement; if the current phase difference is within the [phase1, phase2] resonance interval, it is in zone B or zone D, and execute step S306; otherwise, it is in zone A, zone C, or zone E, and execute step S303;

[0024] Step S303: Determine whether it is in zone C; if the current phase difference signal phase0 is greater than phase2, it is in zone C, and step S308 is executed; otherwise, it is in zone A or zone E, and step S304 is executed;

[0025] Step S304: distinguish between area A and area E; starting from the detuned frequency f0, the frequency search step step 3 is accumulated in a loop, the frequency is decreased to the left to f_left, and the frequency is increased to the right to f_right. When the phase difference between the two ends reaches the set threshold, the loop ends and step S305 is executed;

[0026] Step S305: Determine the phase difference between the left and right ends. If the left phase is smaller than the right phase, it indicates that the phase is increasing to the right and is in zone A. Execute step S309. Otherwise, it is in zone E. Execute step S310.

[0027] Step S306: Distinguish between zone B and zone D; use the monotonicity of the phases of the two intervals to make a judgment. The phase of zone B is monotonically increasing, while the phase of zone D is monotonically decreasing. After reducing the set step frequency, collect the phase difference phase3. If phase3>phase0, the phase increases, then it is zone D, and execute step S307; otherwise, it is zone B, and execute step S312;

[0028] Step S307: After determining that it is zone D, since the current monotonicity in zone D is not unique, to facilitate the maximum current search, the frequency is cyclically reduced until it is reduced to the working area where zone C is located, and then step S311 is executed;

[0029] Step S308: Determine that it is in zone C and set a frequency reduction flag;

[0030] Step S309: Determine that it is in zone A and set a frequency increase flag;

[0031] Step S310: Determine that it is in zone E, reduce the phase to the working area where zone C is located using step S307, and set the frequency increase flag;

[0032] Step S311: After the phase is reduced to the working area where zone C is located, a frequency increase flag is set;

[0033] Step S312: Determine that the area is in zone B and do not perform the maximum current search.

[0034] In step S4, the specific execution steps of the maximum current search are:

[0035] Step S401: Determine whether the frequency decreases; if the frequency decreases, execute step S402; otherwise, execute step S403;

[0036] Step S402: cyclically reducing the frequency until the maximum current value is found;

[0037] Step S403: Determine whether the frequency increases; if the frequency increases, execute step S404; otherwise, execute step S405;

[0038] Step S404: cyclically increase the frequency until the maximum current is found;

[0039] Step S405: Based on the search result, the current frequency is output as the resonant frequency.

[0040] Beneficial effects of the present invention:

[0041] The present invention's phase-positioning-based ultrasonic scalpel resonant frequency tracking system and method combines the advantages of the phase method's rapid search speed with the maximum current method's precise search accuracy. It uses impedance and phase characteristics to divide the ultrasonic scalpel into five phase operating zones. Rapid phase identification is performed through the monotonic characteristics of the phase curve. After locating the phase position, the direction of the maximum current is determined, avoiding multiple determinations of the maximum current direction during the search process and enabling rapid and accurate search for the frequency of the maximum current point. In phase division and determination, the present invention combines frequency sweep results for regional division, primarily utilizing differences in the monotonicity of the operating zones for determination, rather than specific values. Therefore, the system can be applied to phase characteristic curves in various phase ranges, significantly enhancing its applicability to different ultrasonic scalpels. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a structural principle diagram of an ultrasonic tool handle resonant frequency tracking system based on phase positioning according to the present invention;

[0043] Figure 2 This is a flow chart of a method for tracking the resonance frequency of an ultrasonic tool handle based on phase positioning according to the present invention;

[0044] Figure 3 The resonant frequency operating range distribution diagram of the loosely coupled wireless powered ultrasonic tool handle is drawn after impedance characteristic analysis;

[0045] Figure 4 A flow chart of the working phase positioning in the resonant frequency tracking method of the present invention;

[0046] Figure 5 A flowchart of the maximum current search in the resonant frequency tracking method of the present invention;

[0047] In the figure, 100 is a power inverter module, 200 is a signal sampling and processing module, 300 is a microprocessor, 400 is a loosely coupled wireless power supply ultrasonic handle, 500 is an adjustable DC power supply, 101 is a chopper circuit submodule, 102 is a full-bridge inverter circuit submodule, 103 is a power control submodule, 104 is a drive frequency control submodule, 201 is a voltage sampling and filtering submodule, 202 is a phase conversion submodule, 203 is a current sampling and filtering submodule, and 204 is a current effective value conversion submodule. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] like Figure 1 As shown, a phase positioning-based ultrasonic scalpel handle resonant frequency tracking system includes a power inverter module 100, a signal sampling and processing module 200, a microprocessor 300, a loosely coupled wireless power supply ultrasonic scalpel handle 400 and an adjustable DC power supply 500; the current output end of the adjustable DC power supply 500 is electrically connected to the current input end of the power inverter module 100, and the current output end of the power inverter module 100 is divided into two output paths, one path is electrically connected to the loosely coupled wireless power supply ultrasonic scalpel handle 400, and the other path is electrically connected to the current input end of the signal sampling and processing module 200; the signal output end of the signal sampling and processing module 200 is electrically connected to the signal input end of the microprocessor 300, and the signal output end of the microprocessor 300 is electrically connected to the signal input end of the power inverter module 100.

[0050] The power inverter module 100 includes a chopper circuit submodule 101, a full-bridge inverter circuit submodule 102, a power control submodule 103, and a drive frequency control submodule 104; the current input end of the chopper circuit submodule 101 is electrically connected to the current output end of the adjustable DC power supply 500, the current output end of the chopper circuit submodule 101 is electrically connected to the current input end of the full-bridge inverter circuit submodule 102, and the current output end of the full-bridge inverter circuit submodule 102 is divided into two outputs, one of which is electrically connected to the loosely coupled wireless power supply ultrasonic knife handle 400. , the other is electrically connected to the current input end of the signal sampling and processing module 200; the signal input end of the power control submodule 103 is electrically connected to the signal output end of the microprocessor 300, and the signal output end of the power control submodule 103 is electrically connected to the signal input end of the chopper circuit submodule 101; the signal input end of the driving frequency control submodule 104 is electrically connected to the signal output end of the microprocessor 300, and the signal output end of the driving frequency control submodule 104 is electrically connected to the signal input end of the full-bridge inverter circuit submodule 102.

[0051] The signal sampling and processing module 200 includes a voltage sampling and filtering submodule 201, a phase conversion submodule 202, a current sampling and filtering submodule 203, and a current effective value conversion submodule 204. The signal input end of the voltage sampling and filtering submodule 201 is electrically connected to the signal output end of the full-bridge inverter circuit submodule 102, the signal output end of the voltage sampling and filtering submodule 201 is electrically connected to the signal input end of the phase conversion submodule 202, and the signal output end of the phase conversion submodule 202 is electrically connected to the signal input end of the microprocessor 300. The signal input end of the current sampling and filtering submodule 203 is electrically connected to the signal output end of the full-bridge inverter circuit submodule 102, and the signal output end of the current sampling and filtering submodule 203 is divided into two output paths, one path is electrically connected to the signal input end of the phase conversion submodule 202, and the other path is electrically connected to the signal input end of the current effective value conversion submodule 204. The signal output end of the current effective value conversion submodule 204 is electrically connected to the signal input end of the microprocessor 300.

[0052] The power inverter module 100 is used to control and convert the frequency and power of the loosely coupled wireless powered ultrasonic scalpel handle 400; the signal sampling and processing module 200 is used to perform signal sampling and processing; wherein, the voltage sampling and filtering submodule 201 is used to sample and process the voltage signal, the current sampling and filtering submodule 203 is used to sample and process the current signal, the phase conversion submodule 202 is used to extract the phase difference between the voltage and the current, and the current effective value conversion submodule 204 is used to extract the effective value of the current; the microprocessor 300 is used to receive the phase difference signal and the current effective value signal from the signal sampling and processing module 200, and when the resonant frequency of the loosely coupled wireless powered ultrasonic scalpel handle 400 shifts, it is used to issue a control instruction to the power inverter module 100 to quickly and accurately search for the frequency of the maximum current point.

[0053] like Figure 2 As shown, a method for tracking the resonance frequency of an ultrasonic tool handle based on phase positioning adopts the aforementioned ultrasonic tool handle resonance frequency tracking system based on phase positioning, and includes the following steps:

[0054] Step S1: Frequency sweep and impedance analysis

[0055] The frequency of the currently working loosely coupled wireless powered ultrasonic scalpel handle 400 is scanned, and the impedance characteristics of the currently working loosely coupled wireless powered ultrasonic scalpel handle 400 are analyzed to obtain the resonant frequency and resonant phase of the currently working loosely coupled wireless powered ultrasonic scalpel handle 400.

[0056] Step S2: Workspace division

[0057] Within the phase range near the resonant phase, the operating current is maintained near the maximum current point. The resonant frequency range is set according to the required resonant current operating range, and five working areas A, B, C, D, and E are divided accordingly, providing a theoretical basis for the judgment of step S3.

[0058] like Figure 3 As shown, the five working areas A, B, C, D, and E are specifically divided as follows: Area A is the entire area on the left side of the resonance interval of the loosely coupled wireless power ultrasonic scalpel handle 400, far away from the resonance point; Area B is the resonance interval range of the loosely coupled wireless power ultrasonic scalpel handle 400, which is determined by the phase interval corresponding to the allowable resonance current interval; Area C is the area between the resonance interval and the anti-resonance interval of the loosely coupled wireless power ultrasonic scalpel handle 400; Area D is the anti-resonance interval corresponding to the phase value of the resonance interval of the loosely coupled wireless power ultrasonic scalpel handle 400; Area E is the entire area on the right side of the anti-resonance interval of the loosely coupled wireless power ultrasonic scalpel handle 400, far away from the anti-resonance point.

[0059] Specifically, the division of the five working areas A, B, C, D, and E is mainly based on the change law of current and impedance, and is mainly based on the phase interval value and the monotonicity of each area.

[0060] Step S3: Working phase positioning

[0061] When the loosely coupled wireless powered ultrasonic scalpel handle 400 is operating in a detuned state, the working area of ​​the current frequency is judged according to the working areas divided in step S2, and the search direction of the maximum current is determined; among them, area B is in the resonant working area and no search is performed; the frequency of area A is lower than the frequency of the maximum current point, and the search direction is set to increase the frequency; the frequency of areas C, D, and E is higher than the frequency of the maximum current point, and the search direction is set to decrease the frequency.

[0062] like Figure 4 As shown in the figure, the specific steps for working phase positioning are:

[0063] Step S301: According to the five working areas A, B, C, D, and E set in step S2, the microprocessor 300 performs phase capture and collects the current phase difference signal phase0;

[0064] Step S302: Distinguish between AE, BD, and C zones through a judgment statement; if the current phase difference is within the [phase1, phase2] resonance interval, it is in zone B or zone D, and execute step S306; otherwise, it is in zone A, zone C, or zone E, and execute step S303;

[0065] Step S303: Determine whether it is in zone C; if the current phase difference signal phase0 is greater than phase2, it is in zone C, and step S308 is executed; otherwise, it is in zone A or zone E, and step S304 is executed;

[0066] Step S304: distinguish between area A and area E; starting from the detuned frequency f0, the frequency search step step 3 is accumulated in a loop, the frequency is decreased to the left to f_left, and the frequency is increased to the right to f_right. When the phase difference between the two ends reaches the set threshold, the loop ends and step S305 is executed;

[0067] Step S305: Determine the phase difference between the left and right ends. If the left phase is smaller than the right phase, it indicates that the phase is increasing to the right and is in zone A. Execute step S309. Otherwise, it is in zone E. Execute step S310.

[0068] Step S306: Distinguish between zone B and zone D; use the monotonicity of the phases of the two intervals to make a judgment. The phase of zone B is monotonically increasing, while the phase of zone D is monotonically decreasing. After reducing the set step frequency, collect the phase difference phase3. If phase3>phase0, the phase increases, then it is zone D, and execute step S307; otherwise, it is zone B, and execute step S312;

[0069] Step S307: After determining that it is zone D, since the current monotonicity in zone D is not unique, to facilitate the maximum current search, the frequency is cyclically reduced until it is reduced to the working area where zone C is located, and then step S311 is executed;

[0070] Step S308: Determine that it is in zone C and set a frequency reduction flag;

[0071] Step S309: Determine that it is in zone A and set a frequency increase flag;

[0072] Step S310: Determine that it is in zone E, reduce the phase to the working area where zone C is located using step S307, and set the frequency increase flag;

[0073] Step S311: After the phase is reduced to the working area where zone C is located, a frequency increase flag is set;

[0074] Step S312: Determine that the area is in zone B and do not perform the maximum current search.

[0075] Specifically, during the phase location procedure, zone C is the easiest to distinguish, enabling rapid and accurate positioning solely through phase values. Zones A and E exhibit the same phase, a wide range, a gradual phase difference, and an opposite relationship between current and phase, making identification more difficult and time-consuming. In step S304, the different monotonicity of zones A and E during the left and right search processes is utilized to determine the magnitude of the phase difference between the left and right ends, allowing for rapid differentiation between zones A and E. Zones B and D are relatively straightforward and can be identified using their different monotonicity.

[0076] Step S4: Maximum current search

[0077] According to the search direction determined in step S3, the frequency is adjusted monotonically to quickly track the maximum current point, that is, the resonant frequency.

[0078] like Figure 5 As shown in the figure, the specific execution steps of the maximum current search are:

[0079] Step S401: Determine whether the frequency decreases; if the frequency decreases, execute step S402; otherwise, execute step S403;

[0080] Step S402: cyclically reducing the frequency until the maximum current value is found;

[0081] Step S403: Determine whether the frequency increases; if the frequency increases, execute step S404; otherwise, execute step S405;

[0082] Step S404: cyclically increase the frequency until the maximum current is found;

[0083] Step S405: Based on the search result, the current frequency is output as the resonant frequency.

[0084] Specifically, after phase positioning, the direction of frequency increase or decrease is determined, and a cyclic search for the maximum current is performed. At the end of each cycle, the current is compared with the size of the previous cycle. When the cyclic current i1 is less than 1.05 times that of the previous cycle, the cycle is exited and the operation is performed at the previous cycle driving frequency. The 1.05 times parameter setting limits the range of the searched maximum current to more than 95% of the actual maximum current, which can ensure the stability of the searched maximum current and the accuracy of the results.

[0085] The solutions in the embodiments are not intended to limit the patent protection scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention is included in the patent scope of this case.

Claims

1. A method for tracking the resonant frequency of an ultrasonic scalpel handle based on phase positioning, employing a phase positioning-based resonant frequency tracking system for an ultrasonic scalpel handle, the system comprising a power inverter module, a signal sampling and processing module, a microprocessor, a loosely coupled wireless powered ultrasonic scalpel handle, and an adjustable DC power supply; a current output terminal of the adjustable DC power supply is electrically connected to a current input terminal of the power inverter module, the current output terminal of the power inverter module is divided into two output paths, one path is electrically connected to the loosely coupled wireless powered ultrasonic scalpel handle, and the other path is electrically connected to the current input terminal of the signal sampling and processing module; a signal output terminal of the signal sampling and processing module is electrically connected to a signal input terminal of the microprocessor, and a signal output terminal of the microprocessor is electrically connected to a signal input terminal of the power inverter module; The power inverter module includes a chopper circuit submodule, a full-bridge inverter circuit submodule, a power control submodule and a driving frequency control submodule; the current input end of the chopper circuit submodule is electrically connected to the current output end of the adjustable DC power supply, the current output end of the chopper circuit submodule is electrically connected to the current input end of the full-bridge inverter circuit submodule, and the current output end of the full-bridge inverter circuit submodule is divided into two output paths, one path is electrically connected to the loosely coupled wireless power supply ultrasonic knife handle, and the other path is electrically connected to the current input end of the signal sampling and processing module; the signal input end of the power control submodule is electrically connected to the signal output end of the microprocessor, and the signal output end of the power control submodule is electrically connected to the signal input end of the chopper circuit submodule; the signal input end of the driving frequency control submodule is electrically connected to the signal output end of the microprocessor, and the signal output end of the driving frequency control submodule is electrically connected to the signal input end of the full-bridge inverter circuit submodule; The signal sampling and processing module includes a voltage sampling and filtering submodule, a phase conversion submodule, a current sampling and filtering submodule, and a current effective value conversion submodule; the signal input end of the voltage sampling and filtering submodule is electrically connected to the signal output end of the full-bridge inverter circuit submodule, the signal output end of the voltage sampling and filtering submodule is electrically connected to the signal input end of the phase conversion submodule, and the signal output end of the phase conversion submodule is electrically connected to the signal input end of the microprocessor; the signal input end of the current sampling and filtering submodule is electrically connected to the signal output end of the full-bridge inverter circuit submodule, and the signal output end of the current sampling and filtering submodule is divided into two outputs, one of which is electrically connected to the signal input end of the phase conversion submodule and the other is electrically connected to the signal input end of the current effective value conversion submodule, and the signal output end of the current effective value conversion submodule is electrically connected to the signal input end of the microprocessor; The power inverter module is used to control and convert the frequency and power of the loosely coupled wireless powered ultrasonic scalpel handle; the signal sampling and processing module is used to perform signal sampling and processing; wherein, The voltage sampling and filtering submodule is used to sample and process the voltage signal, the current sampling and filtering submodule is used to sample and process the current signal, the phase conversion submodule is used to extract the phase difference between the voltage and the current, and the current effective value conversion submodule is used to extract the effective value of the current; the microprocessor is used to receive the phase difference signal and the effective value signal of the current from the signal sampling and processing module, and to issue a control instruction to the power inverter module when the resonant frequency of the loosely coupled wireless powered ultrasonic scalpel handle shifts, so as to quickly and accurately search for the frequency of the maximum current point; The method is characterized in that it comprises the following steps: Step S1: Frequency sweep and impedance analysis Perform a frequency scan on the currently working loosely coupled wireless powered ultrasonic scalpel handle, and analyze the impedance characteristics of the currently working loosely coupled wireless powered ultrasonic scalpel handle to obtain the resonant frequency and resonant phase of the currently working loosely coupled wireless powered ultrasonic scalpel handle; Step S2: Workspace division In the phase range near the resonant phase, the operating current is maintained near the maximum current point. According to the required resonant current operating range, the resonant frequency range is set, and five working areas A, B, C, D, and E are divided accordingly, providing a theoretical basis for the judgment in step S3; Step S3: Working phase positioning When the loosely coupled wireless powered ultrasonic tool handle is operating in a detuned state, the working area of ​​the current frequency is judged according to the working areas divided in step S2, and the search direction of the maximum current is determined; wherein, area B is in the resonant working area and no search is performed; the frequency of area A is lower than the frequency of the maximum current point, and the search direction is set to increase the frequency; the frequency of areas C, D, and E is higher than the frequency of the maximum current point, and the search direction is set to decrease the frequency; Step S4: Maximum current search According to the search direction determined in step S3, the frequency is adjusted monotonically to quickly track the maximum current point, that is, the resonant frequency.

2. The method for tracking the resonance frequency of an ultrasonic tool handle based on phase positioning according to claim 1, characterized in that: In step S2, the five working areas A, B, C, D, and E are specifically divided as follows: Area A is the entire area on the left side of the resonance interval of the loosely coupled wireless power ultrasonic scalpel handle, far away from the resonance point; Area B is the resonance interval range of the loosely coupled wireless power ultrasonic scalpel handle, which is determined by the phase interval corresponding to the allowable resonance current interval; Area C is the area between the resonance interval and the anti-resonance interval of the loosely coupled wireless power ultrasonic scalpel handle; Area D is the anti-resonance interval corresponding to the phase value of the resonance interval of the loosely coupled wireless power ultrasonic scalpel handle; Area E is the entire area on the right side of the anti-resonance interval of the loosely coupled wireless power ultrasonic scalpel handle, far away from the anti-resonance point.

3. The method for tracking the resonance frequency of an ultrasonic tool handle based on phase positioning according to claim 1, characterized in that: In step S3, the specific steps for working phase positioning are: Step S301: According to the five working areas A, B, C, D, and E set in step S2, the microprocessor performs phase capture and collects the current phase difference signal phase0; Step S302: Distinguish between AE, BD, and C zones through a judgment statement; if the current phase difference is within the [phase1, phase2] resonance interval, it is in zone B or zone D, and execute step S306; otherwise, it is in zone A, zone C, or zone E, and execute step S303; Step S303: Determine whether it is in zone C; if the current phase difference signal phase0 is greater than phase2, it is in zone C, and step S308 is executed; otherwise, it is in zone A or zone E, and step S304 is executed; Step S304: distinguish between area A and area E; starting from the detuned frequency f0, the frequency search step step 3 is accumulated in a loop, the frequency is decreased to the left to f_left, and the frequency is increased to the right to f_right. When the phase difference between the two ends reaches the set threshold, the loop ends and step S305 is executed; Step S305: Determine the phase difference between the left and right ends. If the left phase is smaller than the right phase, it indicates that the phase is increasing to the right and is in zone A. Execute step S309. Otherwise, it is in zone E. Execute step S310. Step S306: Distinguish between zone B and zone D; use the monotonicity of the phases of the two intervals to make a judgment. The phase of zone B is monotonically increasing, while the phase of zone D is monotonically decreasing. After reducing the set step frequency, collect the phase difference phase3. If phase3>phase0, the phase increases, then it is zone D, and execute step S307; otherwise, it is zone B, and execute step S312; Step S307: After determining that it is zone D, since the current monotonicity in zone D is not unique, to facilitate the maximum current search, the frequency is cyclically reduced until it is reduced to the working area where zone C is located, and then step S311 is executed; Step S308: Determine that it is in zone C and set a frequency reduction flag; Step S309: Determine that it is in zone A and set a frequency increase flag; Step S310: Determine that it is in zone E, reduce the phase to the working area where zone C is located using step S307, and set the frequency increase flag; Step S311: After the phase is reduced to the working area where zone C is located, a frequency increase flag is set; Step S312: Determine that the area is in zone B and do not perform the maximum current search.

4. The method for tracking the resonance frequency of an ultrasonic tool handle based on phase positioning according to claim 1, characterized in that: In step S4, the specific execution steps of the maximum current search are: Step S401: Determine whether the frequency decreases; if the frequency decreases, execute step S402; Otherwise, execute step S403; Step S402: cyclically reducing the frequency until the maximum current value is found; Step S403: Determine whether the frequency increases; if the frequency increases, execute step S404; Otherwise, execute step S405; Step S404: cyclically increase the frequency until the maximum current is found; Step S405: Based on the search result, the current frequency is output as the resonant frequency.

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