Tracking method for series resonant frequency of ultrasonic transducer and ultrasonic driving power supply

Abstract

The invention discloses an ultrasonic transducer series resonant frequency tracking method and an ultrasonic driving power supply, and the tracking method comprises the steps: calculating a current phase difference between a voltage signal and a current signal, determining a phase difference error and an error change rate through the combination of a target phase difference, and determining the resonant state of an ultrasonic transducer according to the comparison of the phase difference error and an error threshold value; if the current driving frequency is in the resonance state, keeping the current driving frequency unchanged; and if in a non-resonant state, correcting the driving frequency through a fuzzy PID algorithm. In order to cope with the sudden change of the load, the tracking method introduces an AI model to identify the load and predict the optimal driving frequency, and then the predicted optimal driving frequency is used as the current driving frequency. According to the invention, the response speed and the adjustment precision in dynamic frequency tracking are improved, and adaptive resonance driving and frequency control of the ultrasonic transducer under variable load and variable working conditions can be realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ultrasonic vibration assisted machining, and particularly relates to a tracking method for series resonance frequency of an ultrasonic transducer and an ultrasonic driving power supply. BACKGROUND

[0002] Ultrasonic vibration assisted machining can form alternating contact between the tool tip high-speed vibration and the workpiece material, and realize efficient removal by means of impact and abrasion, which is suitable for cutting, drilling, grinding, milling and other machining methods, and particularly exhibits superior performance in precision machining of difficult-to-machine materials. As the energy supply and control center of the ultrasonic vibration assisted machining system, the ultrasonic driving power supply undertakes the task of converting the power frequency power supply into a high-frequency signal matched with the series resonance frequency of the ultrasonic transducer, and plays a decisive role in the machining efficiency and stability of the system. The ultrasonic transducer will be affected by factors such as load change, temperature rise and structure change during actual machining, resulting in a shift in the series resonance frequency of the ultrasonic transducer. If the frequency of the ultrasonic driving power supply cannot be adjusted in real time, the system will be out of tune, which will reduce the amplitude of the ultrasonic transducer, cause the machining quality to decrease, and even burn out the ultrasonic transducer or power device. Frequency tracking aims to adjust the frequency of the ultrasonic driving power supply to match the series resonance frequency of the ultrasonic transducer. The existing frequency tracking method mainly adopts the PID control method, which is limited in response speed and adjustment precision in dynamic frequency tracking, and is difficult to cope with nonlinear changes under complex working conditions. SUMMARY

[0003] The first object of the present application is to provide a tracking method for series resonance frequency of an ultrasonic transducer with fast response speed and high control precision; and the second object of the present application is to provide an ultrasonic driving power supply.

[0004] Technical scheme: The tracking method for series resonance frequency of an ultrasonic transducer provided by the present application realizes tracking of the series resonance frequency of the ultrasonic transducer based on a fuzzy PID algorithm, and comprises the following steps:

[0005] (1) initializing the parameters of the fuzzy controller, wherein the parameters of the fuzzy controller include a fuzzy rule table; setting an initial driving frequency f0, a target phase difference θ0 and a sampling period T, and setting a loop parameter k = 1;

[0006] (2) acquiring the current driving frequency f k drive the ultrasonic transducer;

[0007] (3) acquiring the voltage signal and the current signal of the ultrasonic transducer, obtaining the amplitude, frequency and phase information of the voltage signal and the amplitude, frequency and phase information of the current signal through a fast Fourier transform algorithm; calculating the current phase difference θ k between the voltage signal and the current signal;

[0008] (4) Calculate current error e k = θ0- θ k and error change rate Δe k = e k - e k-1 , where e k-1 is the error of the last sampling;

[0009] (5) Determine the size between |e k | and ε, if |e k | < ε, the ultrasonic transducer is in resonance state, execute step (6); otherwise, the ultrasonic transducer is in non-resonance state, frequency tracking is needed, execute step (7); ε represents error threshold, which is a set value;

[0010] (6) Keep the current driving frequency f k unchanged and return to step (2);

[0011] (7) Normalize e k and Δe k , so that their values are mapped to a standardized interval as the input of the fuzzy controller; divide the normalized input variables e k and Δe k into multiple fuzzy subsets; according to the triangular membership functions of the current input values falling into each fuzzy subset, calculate the membership values of each fuzzy subset, output a weighted combination of a group of fuzzy subsets through the fuzzy rule table, de-fuzzify the weighted combination of the group of fuzzy subsets to obtain the incremental value of the PID parameters, and use the incremental value of the PID parameters to correct the PID parameters and output the frequency correction amount Δf k through the PID controller; driving frequency f k+1 = f k + Δf k , take the driving frequency f k+1 as the new current driving frequency f k , update k = k + 1, and return to step (2);

[0012] (8) Loop steps (2) to (7) to realize dynamic frequency adjustment.

[0013] Further, the fuzzy controller parameters further include proportional coefficient K p , integral coefficient K i , and differential coefficient K d .

[0014] Further, when the ultrasonic driving power supply is initially started, if the series resonance frequency of the ultrasonic transducer is known, the series resonance frequency is manually set as the initial driving frequency f0; if the series resonance frequency of the ultrasonic transducer is unknown, a frequency scanning of the ultrasonic transducer in a set frequency range is performed based on a bisection method, and the frequency at which the phase difference between the voltage signal and the current signal is the smallest is taken as the initial driving frequency f0.

[0015] Further, an AI model for optimal driving frequency prediction and load identification is constructed, and the AI model is trained by using the characteristic parameters of the ultrasonic transducer under different load working states and the corresponding series resonance frequencies; the characteristic parameters include the amplitude, frequency and phase of the voltage signal, the amplitude, frequency and phase of the current signal, and the phase difference between the voltage signal and the current signal; when the resonance frequency offset exceeds the offset threshold, it is determined that the load characteristics of the ultrasonic transducer have changed, at this time, the characteristic parameters obtained at present are input into the trained AI model, the current load working state is identified, and the predicted optimal driving frequency f AI is output. AI As the current driving frequency f k ; the offset threshold is a set value.

[0016] The existing ultrasonic driving power supply generally cannot identify the load change in real time and adjust the output frequency and power accordingly, resulting in low energy transmission efficiency of the ultrasonic transducer and unstable system operation. The present application introduces an AI model, uses characteristic parameters to realize load working state identification and optimal driving frequency prediction, and can realize dynamic matching of the output signal frequency and power of the ultrasonic driving power supply and the ultrasonic transducer. The AI model improves the response speed and self-adaptive ability to load changes, realizes the real-time and accuracy of power regulation, and enhances the stability of the ultrasonic driving power supply. In combination with the fuzzy PID algorithm, the present application realizes adaptive resonance driving and frequency control of the ultrasonic transducer under variable load and variable working conditions.

[0017] Further, the plurality of fuzzy subsets are negative large, negative medium, negative small, zero, positive small, positive medium and positive large.

[0018] The ultrasonic driving power supply of the present application comprises:

[0019] The signal sampling and conditioning circuit module is used for collecting the current signal and the voltage signal of the ultrasonic transducer, and inputting the amplified and filtered collected signals into the control module.

[0020] The control module has a microcontroller and a memory, and the memory stores a computer program, when the computer program is executed by the microcontroller, the steps of the tracking method are realized, and the current driving frequency f k of the ultrasonic transducer is determined; the microcontroller is also used for outputting the frequency and the current driving frequency fk consistent and duty cycle, frequency adjustable two-way complementary PWM signal;

[0021] A driving circuit module is configured to receive the PWM signal output by the control module and convert the direct current into a square wave signal with the same frequency as the PWM signal.

[0022] An impedance matching circuit module is configured to achieve impedance matching between the driving circuit module and the ultrasonic transducer. The square wave signal is loaded onto the ultrasonic transducer after impedance matching.

[0023] Further, the impedance matching circuit module has a plurality of resonance branches, each of which is provided with an inductor, a capacitor combination, and a relay for controlling the on-off of the corresponding resonance branch. The resonance parameters of the inductor and capacitor combination in each resonance branch are different. The microcontroller is further configured to, according to a human control instruction, connect one resonance branch and disconnect the other resonance branches when the ultrasonic driving power source is initially started. The connected resonance branch satisfies the condition of minimizing the target phase difference θ0, realizing impedance matching between the ultrasonic driving power source and the ultrasonic transducer, and ensuring that the driving frequency is adapted to the impedance characteristics.

[0024] In existing ultrasonic driving power sources, impedance matching usually relies on fixed LC parameter design, which is difficult to adapt to different ultrasonic transducers or load conditions, resulting in a mismatch between the ultrasonic driving power source output signal frequency and the transducer resonance point, affecting energy transmission efficiency and system stability. The present application sets multiple LC branches with different resonance parameters in the impedance matching circuit and controls the relay switching by the microcontroller, so that the ultrasonic driving power source can select the appropriate resonance branch according to the human control instruction during the initialization stage, and quickly complete the impedance matching. The impedance matching circuit module structure realizes flexible configuration of impedance matching parameters, enhances the adaptability of the ultrasonic driving power source to different loads and working conditions, and effectively improves the resonance working stability and energy transmission efficiency of the transducer.

[0025] Further, the control module also has physical buttons and a human-computer interaction display screen. The physical buttons are used for system parameter setting, start or stop operation. The human-computer interaction display screen is used to display the system working state, frequency, voltage, current and phase information in real time.

[0026] Further, the drive circuit module comprises a direct current chopper circuit and a full-bridge inverter circuit, the direct current chopper circuit is used for converting input 220V alternating current into direct current through rectification and filtering processing, and adjusting the output voltage amplitude through the control instruction sent by the microcontroller, so as to provide controllable direct current power for the full-bridge inverter circuit, so as to meet the demand for different driving power under different working conditions; the full-bridge inverter circuit comprises a full-bridge structure composed of four MOSFET devices and a group of MOSFET drivers; the PWM signal output by the control module controls the MOSFET devices to work in an alternating conduction mode through the MOSFET drivers, so as to convert the direct current into high-frequency alternating current signals, and then drive the ultrasonic transducer to generate ultrasonic vibration.

[0027] Further, the signal sampling and conditioning circuit module comprises:

[0028] A voltage transformer is used for collecting the voltage signal of the transducer;

[0029] A current transformer is used for collecting the current signal of the transducer;

[0030] Two amplification circuits are used for adjusting the amplitudes of the collected voltage signal and current signal, respectively;

[0031] Two band-pass filter circuits are used for filtering out the harmonics and noise of the voltage signal and current signal, respectively, so as to obtain clean signals of main frequency components; the obtained clean signals of main frequency components are input into the control module.

[0032] Beneficial effects: compared with the prior art, the present application has the following remarkable advantages: based on the comparison between the error of the phase difference of the voltage and current signals and the set error threshold, the resonance state of the ultrasonic transducer is determined, and the fuzzy PID algorithm is used for adjusting the series resonance frequency of the ultrasonic transducer, so as to improve the response speed and adjustment accuracy in dynamic frequency tracking, and effectively enhance the adaptability of the ultrasonic drive power supply. BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1 is the flow chart of the frequency tracking algorithm based on fuzzy PID in the embodiment of the present application;

[0034] Fig. 2 is the flow chart of the joint control of the AI model and the fuzzy PID algorithm;

[0035] Fig. 3 is the structural schematic diagram of the ultrasonic drive power supply provided by the embodiment of the present application. DETAILED DESCRIPTION

[0036] The present application will be further described below in combination with the drawings.

[0037] The drawings in the accompanying drawings are as follows: Figs. 1 to 3 ​

[0038] 1. Control module; 2. Drive circuit module; 3. Impedance matching circuit module; 4. Signal sampling and conditioning circuit module; 5. Microcontroller; 6. Physical buttons; 7. Human-machine interface display screen; 8. MOSFET driver; 9. MOSFET device; 10. Ultrasonic transducer; 11. Current transformer; 12. Voltage transformer; 13 / 14. Bandpass filter circuit; 15. Relay.

[0039] Example 1

[0040] like Fig. 1 As shown, Example 1 provides a method for tracking the series resonant frequency of an ultrasonic transducer. The method is based on a fuzzy PID algorithm to track the series resonant frequency of the ultrasonic transducer, and includes the following steps:

[0041] (1) Initialize the fuzzy controller parameters, including the proportional coefficient K. p Integral coefficient K i Differential coefficient K d And fuzzy rule table; set initial driving frequency f0, target phase difference θ0 and sampling period T, and let loop parameter k = 1; target phase difference θ0 is the theoretical phase difference value of ultrasonic transducer in resonance state, such as zero phase difference.

[0042] When the ultrasonic drive power supply is initially started, if the series resonant frequency of the ultrasonic transducer is known, the series resonant frequency is manually set as the initial drive frequency f0; if the series resonant frequency of the ultrasonic transducer is unknown, the ultrasonic transducer is scanned within a set frequency range (e.g., 20kHz to 40kHz) based on the bisection method frequency sweep algorithm, and the frequency at which the phase difference between the voltage signal and the current signal is the smallest is taken as the initial drive frequency f0.

[0043] (2) At the current driving frequency f k Drive the ultrasonic transducer;

[0044] (3) Acquire the voltage and current signals of the ultrasonic transducer, and obtain the amplitude, frequency, and phase information of the voltage signal and the amplitude, frequency, and phase information of the current signal through the Fast Fourier Transform algorithm; calculate the current phase difference θ between the voltage and current signals. k ;

[0045] (4) Calculate the current error e k =θ0-θ k and the rate of change of error Δe k =e k -e k-1 , where e k-1 This represents the error from the previous sampling.

[0046] (5) Determine |e k|e| < ε, the ultrasonic transducer is in a resonant state, and step (6) is performed; otherwise, the ultrasonic transducer is in a non-resonant state, and frequency tracking needs to be performed, and step (7) is performed; ε represents an error threshold, which is a set value; k |e| < ε, the ultrasonic transducer is in a resonant state, and step (6) is performed; otherwise, the ultrasonic transducer is in a non-resonant state, and frequency tracking needs to be performed, and step (7) is performed; ε represents an error threshold, which is a set value;

[0047] If the ultrasonic transducer is in a resonant state, it works at an optimal state point, with the maximum amplitude and the minimum energy loss. If it is in a non-resonant state, frequency tracking needs to be performed to make the frequency of the output PWM signal consistent with the resonant frequency.

[0048] (6) keeping the current driving frequency f k unchanged and returning to step (2);

[0049] (7) performing normalization processing on e k and Δe k , so that values of e k and Δe k are mapped to a standardized interval as inputs of a fuzzy controller; dividing the normalized input variables e k and Δe k+1 into a plurality of fuzzy subsets, respectively, negative big (NB), negative medium (NM), negative small (NS), zero (ZO), positive small (PS), positive medium (PM) and positive big (PB); calculating membership values of the current input values to each fuzzy subset according to a triangular membership function of each fuzzy subset; outputting a weighted combination of a group of fuzzy subsets through a fuzzy rule table; performing defuzzification processing on the weighted combination of the group of fuzzy subsets to obtain an incremental value of a PID parameter; and correcting the PID parameter by using the incremental value of the PID parameter and outputting a frequency correction amount Δf k through a PID controller; k k+1 k , updating k = k + 1, and returning to step (2);

[0050] (8) cyclically performing steps (2) to (7) to realize dynamic frequency adjustment.

[0051] The fuzzy PID control algorithm is used to keep the ultrasonic transducer in a working state. The fuzzy PID controller takes the phase difference error and the error change rate as inputs, judges the adjustment strategy through a fuzzy rule table, and outputs a frequency correction amount to realize fine adjustment control of the frequency. However, the fuzzy PID control algorithm alone cannot effectively cope with the case of sudden load change. Therefore, in combination with Fig. 2 , the ultrasonic transducer series resonant frequency tracking method provided in Embodiment 1 further performs the following operations:

[0052] ​​An AI model for optimal driving frequency prediction and load identification is constructed, which is developed by AISTUDIO provided by ST Company and is a lightweight neural network. The AI model is trained by using the characteristic parameters of the ultrasonic transducer under different load working conditions and the corresponding series resonance frequency; the characteristic parameters include the amplitude, frequency and phase of the voltage signal, the amplitude, frequency and phase of the current signal, and the phase difference between the voltage signal and the current signal.

[0053] When the resonance frequency offset exceeds the offset threshold, it is determined that the load characteristics of the ultrasonic transducer have changed (for example, workpiece contact, temperature change, etc.), at this time, the characteristic parameters obtained at present are input into the trained AI model, the current load working condition is identified, and the predicted optimal driving frequency f AI is output. AI As the current driving frequency f k , the resonance frequency offset is determined by comparing the driving frequency data obtained in real time with the series resonance frequency.

[0054] In actual operation, when the load working condition changes, for example, the load impedance changes, the reflected signal amplitude changes sharply, etc., at this time, the resonance frequency offset will exceed the offset threshold, the original fuzzy PID algorithm for frequency control needs to be interrupted, the optimal driving frequency is determined by the AI model, and the optimal driving frequency is temporarily used as the current driving frequency, and then the original fuzzy PID algorithm is combined for frequency control, so as to quickly approach the new resonance frequency. The purpose of identifying the load working condition in the application is to automatically adjust the voltage amplitude and duty cycle control parameters according to the load characteristics, and to adjust the output power of the ultrasonic driving power supply to the ultrasonic transducer.

[0055] Embodiment 2

[0056] As shown in Fig. 3 , embodiment 2 provides an ultrasonic driving power supply, which comprises a control module 1, a driving circuit module 2, an impedance matching circuit module 3 and a signal sampling and conditioning circuit module 4.

[0057] I. Control module

[0058] The control module 1 has a microcontroller 5, a memory, physical buttons 6 and a human-computer interaction display screen 7, wherein the microcontroller 5 adopts an STM32 microcontroller, the memory stores a computer program, and the computer program is written by a Keil5MDK programming platform.

[0059] The microcontroller 5 is internally integrated with multiple peripheral interfaces, including an ADC (analog-to-digital conversion) sampling module, a PWM output module, a serial communication interface, and an interrupt control module. The user can set system parameters, start or stop operations through the physical button 6, and the man-machine interactive display screen 7 is used to display real-time system working state, frequency, voltage, current, and phase information.

[0060] When the computer program is executed by the microcontroller, the steps of the tracking method described in Embodiment 1 are implemented, including:

[0061] 1) Sampling the voltage signal and the current signal of the ultrasonic transducer through the ADC sampling module;

[0062] 2) Extracting the amplitude, frequency, and phase information of the voltage and current signals through the fast Fourier transform (FFT) algorithm, and calculating the phase difference;

[0063] 3) Dynamically adjusting the current driving frequency f k of the ultrasonic transducer based on the fuzzy PID algorithm;

[0064] 4) Calling the AI model to realize current load state recognition and optimal driving frequency f AI prediction, taking the predicted optimal driving frequency f AI as the current driving frequency f k ;

[0065] 5) Outputting the frequency consistent with the current driving frequency f k and the two-way complementary PWM signal (PWM signal is an adjustable duty cycle square wave signal, and frequency is one of its parameters) with adjustable duty cycle and frequency, which is used to drive the full-bridge inverter circuit to adjust the output power of the ultrasonic drive power supply.

[0066] The microcontroller 5 can dynamically adjust the frequency parameter of the PWM signal according to the output of the fuzzy PID algorithm, so that the output frequency of the ultrasonic drive power supply stably follows the real-time resonance point of the ultrasonic transducer, thereby realizing the dynamic frequency tracking function. The entire process does not require manual intervention and has high automation characteristics.

[0067] II. Drive circuit module

[0068] The drive circuit module 2 includes a direct current chopper circuit and a full-bridge inverter circuit. The direct current chopper circuit is used to convert the input 220V alternating current into direct current after rectification and filtering processing, and adjust the output voltage amplitude through the control instruction sent by the microcontroller 5, so as to provide controllable direct current power for the full-bridge inverter circuit, so as to meet the demand for different driving power under different working conditions. The full-bridge inverter circuit includes a full-bridge structure composed of four MOSFET devices 9 and a set of MOSFET drivers 8. The PWM signal output by the control module 1 controls the MOSFET devices 9 through the MOSFET drivers 8 to work in an alternating conduction mode, so as to convert the direct current into a high-frequency alternating current signal (for the frequency and the current driving frequency f k The same square wave signal) with a frequency not less than 20kHz, and then drive the ultrasonic transducer 10 to generate ultrasonic vibration.

[0069] The drive circuit module 2 can quickly respond to the PWM adjustment instruction sent by the control module 1, so as to realize accurate frequency control and power output adjustment.

[0070] III. Impedance matching circuit module

[0071] The impedance matching circuit module 3 has a plurality of resonance branches, each of which is provided with an inductance-capacitance combination and a relay 15 for controlling the on-off of the corresponding resonance branch. Each relay 15 is controlled by the microcontroller 5, and the resonance parameters of the inductance-capacitance combination in each resonance branch are different. When the ultrasonic drive power is initially started, the microcontroller 5 connects one resonance branch and disconnects the other resonance branches according to the human control instruction. The connected resonance branch satisfies the condition that the target phase difference θ0 is minimum, so as to realize the impedance matching between the ultrasonic drive power and the ultrasonic transducer, and ensure that the driving frequency is adapted to the impedance characteristics. The square wave signal is loaded on the ultrasonic transducer 10 after impedance matching.

[0072] IV. Signal sampling and conditioning circuit module

[0073] The signal sampling and conditioning circuit module 4 includes a current transformer 11, a voltage transformer 12, a band-pass filter circuit 13, a band-pass filter circuit 14 and two amplification circuits. The current transformer 11 collects the current signal of the ultrasonic transducer 10, the voltage transformer 12 collects the voltage signal across the ultrasonic transducer 10, and the two amplification circuits adjust the amplitudes of the collected voltage signal and current signal, respectively. The two band-pass filter circuits filter out the harmonics and noise of the voltage signal and current signal to obtain clean signals with main frequency components, which are finally sent to the ADC sampling module of the microcontroller 5.

[0074] STM32 microcontroller configures the advanced control function of the timer to generate four-way PWM signals. Two-way is complementary PWM waveform, using the complementary channel function output of the timer, controlling the upper and lower bridge arms of the full-bridge inverter circuit, realizing the integrity and safety of the driving signal. The other two are adjustable duty ratio PWM waveforms, used to adjust the output voltage amplitude. By modifying the duty ratio of the PWM, the adjustment of the DC voltage amplitude can be realized, thereby finely controlling the effective power input to the full-bridge inverter circuit and adjusting the working power of the ultrasonic transducer. The output of the full-bridge inverter circuit is a high-frequency alternating voltage, which is connected to a step-up transformer for voltage raising processing, and the output end is connected to an impedance matching circuit module 3. The high-frequency alternating voltage after step-up is loaded onto the ultrasonic transducer 10. Through the timer control periodic trigger sampling, continuous data streams of voltage and current are obtained.

Claims

1. A method of tracking the series resonant frequency of an ultrasonic transducer, characterized by, The fuzzy PID algorithm is used to realize the series resonance frequency tracking of the ultrasonic transducer, including: (1) initializing the fuzzy controller parameters, the fuzzy controller parameters including a fuzzy rule table; setting an initial driving frequency f0, a target phase difference θ0 and a sampling period T, and setting a loop parameter k = 1; (2) at the current drive frequency f k driving the ultrasound transducer; (3) Collecting the voltage signal and the current signal of the ultrasonic transducer, obtaining the amplitude, frequency and phase information of the voltage signal and the amplitude, frequency and phase information of the current signal through fast Fourier transform algorithm; calculating the current phase difference θ of the voltage signal and the current signal k ; (4) Calculate the current error e k = θ0- θ k and the error rate of change Δe k = e k - e k-1 where e k-1 is the error of the last sample; (5) judge |e k | and ε, if |e k | < ε, the ultrasonic transducer is in resonance state, and step (6) is executed; otherwise, the ultrasonic transducer is in non-resonance state, and frequency tracking is needed, and step (7) is executed; ε represents an error threshold value, which is a set value; (6) keep the current drive frequency f k unchanged and return to step (2); (7) e k With Δe k Normalization is performed to map its value to a standardized interval as the input to the fuzzy controller; the normalized input variable e is then used as the input to the fuzzy controller. k With Δe k The input is divided into multiple fuzzy subsets. Based on the triangular membership function of the current input value falling into each fuzzy subset, its membership value for each subset is calculated. A weighted combination of fuzzy subsets is output through a fuzzy rule table. This weighted combination is then defuzzified to obtain the incremental values ​​of the PID parameters. These incremental values ​​are used to correct the PID parameters, and the frequency correction Δf is output through the PID controller. k Drive frequency f k+1 =f k +Δf k , drive frequency f k+1 As the new current driving frequency f k Update k = k + 1 and return to step (2); (8) cyclically executing steps (2) to (7) to realize dynamic frequency adjustment.

2. The method of tracking the series resonant frequency of an ultrasonic transducer of claim 1, wherein, The fuzzy controller parameters further include a proportional coefficient K p , an integral coefficient K i , and a differential coefficient K d .

3. The method of tracking series resonance frequency of an ultrasonic transducer of claim 1, wherein, When the ultrasonic driving power is initially started, if the series resonance frequency of the ultrasonic transducer is known, the series resonance frequency is manually set as the initial driving frequency f0; if the series resonance frequency of the ultrasonic transducer is unknown, a frequency scanning of the ultrasonic transducer in a set frequency range is performed based on a dichotomy sweep algorithm, and the frequency at which the phase difference between the voltage signal and the current signal is the smallest is taken as the initial driving frequency f0.

4. The method of tracking series resonance frequency of an ultrasonic transducer of claim 3, wherein, An AI model for optimal driving frequency prediction and load identification is constructed, and the AI model is trained using feature parameters of the ultrasonic transducer under different load working states and corresponding series resonance frequencies; the feature parameters include amplitude, frequency, and phase of the voltage signal, amplitude, frequency, and phase of the current signal, and phase difference between the voltage signal and the current signal; when the resonance frequency offset exceeds the offset threshold, it is determined that the load characteristics of the ultrasonic transducer have changed abruptly, at this time, the current acquired feature parameters are input into the trained AI model, the current load working state is identified, and the predicted optimal driving frequency f AI The predicted optimal driving frequency f AI is taken as the current driving frequency f k ; and the offset threshold is a set value.

5. The method of tracking series resonance frequency of an ultrasonic transducer of claim 1, wherein, The plurality of fuzzy subsets are negative large, negative medium, negative small, zero, positive small, positive medium and positive large.

6. An ultrasonic drive power supply characterized by comprising: It comprises: a signal sampling and conditioning circuit module for collecting the current signal and the voltage signal of the ultrasonic transducer, and inputting the amplified and filtered signals into the control module; a control module having a microcontroller and a memory, the memory having stored therein a computer program which, when executed by the microcontroller, implements the steps of the tracking method of any one of claims 1 to 5, determining a current drive frequency f k for driving the ultrasound transducer; the microcontroller is further configured to output two complementary PWM signals having a duty cycle k that is in accordance with the determined current drive frequency f a driving circuit module for receiving the PWM signal output by the control module and converting the direct current into a square wave signal with the same frequency as the PWM signal; an impedance matching circuit module for realizing the impedance matching between the driving circuit module and the ultrasonic transducer; the square wave signal is loaded onto the ultrasonic transducer after impedance matching.

7. The ultrasonic drive power supply of claim 6, wherein, The impedance matching circuit module has a plurality of resonance branches, each of which is provided with an inductance-capacitance combination and a relay for controlling the on-off of the corresponding resonance branch; the resonance parameters of the inductance-capacitance combination in each resonance branch are different; the microcontroller is further configured to, when the ultrasonic driving power is initially started, connect one resonance branch and disconnect the other resonance branches according to the human control instruction; the connected resonance branch satisfies the minimum target phase difference θ0, realizes the impedance matching between the ultrasonic driving power and the ultrasonic transducer, and ensures that the driving frequency is adapted to the impedance characteristics.

8. The ultrasonic drive power supply of claim 6, wherein, The control module further has physical buttons and a man-machine interaction display screen, the physical buttons are used for system parameter setting, starting or stopping operation; the man-machine interaction display screen is used for real-time display of system working state, frequency, voltage, current and phase information.

9. The ultrasonic drive power supply of claim 6, wherein, The driving circuit module includes a direct current chopping circuit and a full-bridge inverter circuit, the direct current chopping circuit is used for converting the input 220V alternating current into direct current after rectification and filtering, and adjusting the output voltage amplitude through the control instruction sent by the microcontroller to provide a controllable direct current power for the full-bridge inverter circuit, so as to meet the demand for different driving power under different working conditions; the full-bridge inverter circuit includes a full-bridge structure composed of four MOSFET devices and a MOSFET driver; the PWM signal output by the control module controls the MOSFET devices to work in an alternating on-off mode through the MOSFET driver, converts the direct current into a high-frequency alternating current signal, and then drives the ultrasonic transducer to generate ultrasonic vibration.

10. The ultrasonic drive power supply of claim 6, wherein, The signal sampling and conditioning circuit module comprises: a voltage transformer for collecting the voltage signal across the transducer; a current transformer for collecting the current signal of the transducer; two amplification circuits for adjusting the amplitudes of the collected voltage signal and current signal, respectively; Two-way band-pass filter circuit is used for filtering out the harmonic and noise of voltage signal and current signal respectively, and clean signal of main frequency component is obtained; the clean signal of main frequency component is input into the control module.

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