Resonant frequency tracking method and device of megasonic power supply, medium and product

Abstract

The invention discloses a resonant frequency tracking method and device for a megasonic power supply, a medium and a product, and relates to the field of frequency tracking, and the method comprises the steps: obtaining a voltage signal and a current signal of an ultrasonic transducer at a current driving frequency; determining the phase difference between the two; determining a current phase difference frequency according to the phase difference; if the difference value between the current phase difference frequency and the rated series resonant frequency is within a preset frequency threshold range, the current phase difference frequency is a preliminary screening frequency, otherwise, error compensation is carried out on the current phase difference frequency; under the preliminary screening frequency, the driving frequency of the megasonic power supply is adjusted based on a second preset step length frequency, and then the maximum power of the ultrasonic transducer is determined; the driving frequency corresponding to the maximum power is the optimized resonant frequency; adjusting the driving frequency of the megasonic power supply to the optimized resonant frequency; the method can efficiently determine the real-time optimal resonant frequency, meets the frequency tracking requirements of short adjustment time and high tracking precision, and improves the performance of a megasonic system.

Description

Technical Field

[0001] The present application relates to the field of frequency tracking, and particularly to a resonance frequency tracking method, device, medium and product for a megasonic power supply. Background Art

[0002] Megasonic systems are widely used in fields such as cleaning and detection. Existing megasonic systems mainly consist of a megasonic power supply, a piezoelectric transducer, etc. The function of the megasonic power supply is to convert electrical energy into a high-frequency alternating current signal that matches the piezoelectric transducer. The piezoelectric transducer, as a key load of the megasonic power supply, can convert alternating current electrical energy into mechanical energy. The piezoelectric transducer can transfer power at the maximum when working at the series resonance frequency (also known as the resonance frequency). However, during operation, serious self-heating effects will occur in the stress concentration area inside the piezoelectric transducer, resulting in a significant drift of the resonance frequency. This requires the megasonic power supply to be able to automatically detect and track the resonance frequency, and at the same time quickly adjust the output frequency so that the operating frequency of the megasonic power supply can match the resonance frequency of the piezoelectric transducer.

[0003] Currently, the common frequency tracking scheme is the phase-locked loop frequency tracking method, that is, detecting the output voltage and output current of the entire ultrasonic power supply, realizing frequency tracking through voltage-current phase locking, then calculating the tracking result, and further adjusting the power supply output. This technology controls and adjusts the series resonance frequency according to the phase difference between the current and voltage applied to the transducer, and regards the in-phase of the current and voltage as the best resonance characteristic, that is, tracking the zero-phase frequency of the transducer. However, due to the existence of the parallel static capacitance of the transducer, the zero-phase frequency is not equal to the resonance frequency. Although the static capacitance can be compensated by a matching network with additional reactance elements, fluctuations in the load, inductance, and capacitance will cause the matching network to be invalid, resulting in deviation of the tracking result. Moreover, in high-frequency applications, the difference between the zero-phase frequency and the resonance frequency is even greater. Therefore, the phase-locked scheme with the phase zero point as the resonance marker point will cause the transducer to work in a non-optimal resonance state, resulting in incomplete resonance of the transducer and reducing the power supply efficiency.

[0004] Therefore, based on the above problems, there is an urgent need to provide a new resonance frequency tracking method or system for a megasonic power supply, which can efficiently determine the real-time optimal resonance frequency, meet the frequency tracking requirements of short adjustment time and high tracking accuracy, and thus improve the performance of the megasonic system. Summary of the Invention

[0005] The purpose of the present application is to provide a new resonance frequency tracking method, device, medium and product for a megasonic power supply, so that the megasonic power supply can accurately determine and track the best resonance frequency, meet the frequency tracking requirements of short adjustment time and high tracking accuracy, and thus improve the performance of the megasonic system.

[0006] To achieve the above purpose, the present application provides the following solutions:

[0007] In a first aspect, the present application provides a resonant frequency tracking method for a megasonic power supply, including:

[0008] For any AC signal at the output driving frequency of the megasonic power supply to drive the ultrasonic transducer to work,

[0009] Obtain the voltage signal and current signal of the ultrasonic transducer at the current driving frequency; the initial value of the current driving frequency is the rated series resonance frequency of the ultrasonic transducer;

[0010] According to the voltage signal and the current signal, determine the phase difference between the voltage signal and the current signal;

[0011] According to the phase difference, determine the current phase difference frequency;

[0012] Judge whether the difference between the current phase difference frequency and the rated series resonance frequency is within a preset frequency threshold range. If so, the current phase difference frequency is the preliminary screening frequency; otherwise, perform error compensation on the current phase difference frequency to update the current driving frequency until the difference between the current phase difference frequency and the rated series resonance frequency is within the preset frequency threshold range;

[0013] At the preliminary screening frequency, based on the second preset step frequency, adjust the driving frequency of the megasonic power supply, collect the power of the ultrasonic transducer at different driving frequencies, search for each power, and determine the maximum power of the ultrasonic transducer; the driving frequency corresponding to the maximum power is the optimized resonance frequency;

[0014] Adjust the driving frequency of the megasonic power supply to the optimized resonance frequency.

[0015] Optionally, the determining the phase difference between the voltage signal and the current signal according to the voltage signal and the current signal specifically includes:

[0016] Determine a first sine reference signal and a second sine reference signal; the first sine reference signal and the second sine reference signal have the same amplitude and are orthogonal to each other;

[0017] According to the voltage signal, the current signal, the first sine reference signal and the second sine reference signal, determine the active power and the reactive power;

[0018] According to the active power and the reactive power, determine the phase difference between the voltage signal and the current signal.

[0019] Optionally, the phase difference is determined according to the following formula:

[0020]

[0021] Wherein, is the phase difference between the voltage signal and the current signal, P is the active power, Q is the reactive power, and y u1 (t) is the result of filtering after multiplying the voltage signal by the first sine reference signal, and y u2 (t) is the result of filtering after multiplying the voltage signal by the second sine reference signal, and y i1 (t) is the result of filtering after multiplying the current signal by the first sine reference signal, and y i2 (t) is the result of filtering after multiplying the current signal by the second sine reference signal, and V m is the voltage signal amplitude, and I m is the current signal amplitude, and t is the current time.

[0022] Optionally, determining the current phase difference frequency according to the phase difference specifically includes:

[0023] Judging whether the phase difference is within a preset phase difference threshold. If it is, the current driving frequency is the phase difference frequency; otherwise, based on the first preset step frequency, adjust the current driving frequency until the phase difference is within the preset phase difference threshold; wherein, the first preset step frequency is greater than the second preset step frequency.

[0024] Optionally, determine the phase difference frequency after error compensation according to the following formula:

[0025]

[0026] κ = f r / f s ;

[0027] wherein, f drive is the phase difference frequency after error compensation, f r * is the phase difference frequency, κ is the error compensation coefficient, f s is the rated series resonance frequency, and f r is the zero-phase frequency.

[0028] Optionally, the process of determining the maximum power of the ultrasonic transducer includes:

[0029] Judging whether the power of the ultrasonic transducer at time k satisfies the formula |(P(k) - P(k - 1)) / P(k - 1)| < ε; if so, the power of the ultrasonic transducer at time k is the maximum power, otherwise adjust the driving frequency according to the derivative value of the power with respect to the driving frequency until the power of the ultrasonic transducer satisfies the formula |(P(k) - P(k - 1)) / P(k - 1)| < ε;

[0030] wherein, P(k) is the power of the ultrasonic transducer at time k, P(k - 1) is the power of the ultrasonic transducer at time k - 1, and ε is the preset power threshold.

[0031] Optionally, after adjusting the driving frequency of the megasonic power supply to the optimized resonance frequency, the method further includes:

[0032] Determining a pulse width modulation driving signal according to the optimized resonance frequency;

[0033] Driving the megasonic power supply with the pulse width modulation driving signal to generate high-frequency alternating current; the high-frequency alternating current is used to supply power to the ultrasonic transducer.

[0034] In a second aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement the steps of the resonance frequency tracking method of the megasonic power supply described in any one of the above.

[0035] In a third aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the resonance frequency tracking method of the megasonic power supply described in any one of the above are implemented.

[0036] In a fourth aspect, the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, the steps of the resonance frequency tracking method of the megasonic power supply described in any one of the above are implemented.

[0037] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0038] The present application provides a resonance frequency tracking method, device, medium, and product for a megasonic power supply. By calculating the phase difference between the current signal and the voltage signal to determine the current phase difference frequency, comparing the difference between the current phase difference and the rated series resonance frequency, and combining the change trend of power, error frequency compensation is performed. The driving frequency of the megasonic power supply is adjusted by a second preset step frequency, and then the change trend of power is combined again to determine the maximum power of the ultrasonic transducer, and further determine the optimized resonance frequency; that is, the present application adjusts the frequency according to the change trend of the frequency, overcomes the deficiencies of the traditional frequency tracking method, solves the problem of power consumption loss caused by the neglect of the difference between the series resonance frequency and the zero-phase frequency at megahertz high frequencies, meets the frequency tracking requirements of short adjustment time and high tracking accuracy, and further improves the performance of the megasonic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0040] Figure 1 It is a schematic flowchart of the resonant frequency tracking method of the megasonic power supply in an embodiment of the present application;

[0041] Figure 2 It is a schematic diagram of the megasonic system in an embodiment of the present application;

[0042] Figure 3 It is a schematic diagram of the equivalent circuit of the ultrasonic transducer in an embodiment of the present application;

[0043] Figure 4 It is a detailed flowchart of the resonant frequency tracking method of the megasonic power supply in an embodiment of the present application;

[0044] Figure 5 It is a frequency tracking effect diagram of the resonant frequency tracking method of the megasonic power supply in an embodiment of the present application;

[0045] Figure 6 It is a frequency tracking effect diagram of the traditional tracking method;

[0046] Figure 7 It is a comparison diagram of the effects of the resonant frequency tracking method of the megasonic power supply and the traditional tracking method;

[0047] Figure 8 It is a schematic diagram of the structure of a computer device provided in an embodiment of the present application.

[0048] Reference numerals: L1 - dynamic inductance, C1 - dynamic capacitance, R1 - dynamic resistance, C0 - dynamic capacitance. Detailed implementation manners

[0049] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0050] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0051] In an exemplary embodiment, as Figure 1 shown, a resonant frequency tracking method of a megasonic power supply is provided. As Figure 2 shown, the megasonic system includes a megasonic power supply, an ultrasonic transducer, and an FPGA. When the alternating current signal at any driving frequency output by the megasonic power supply drives the ultrasonic transducer to work, the method includes the following S1 - S6. Among them:

[0052] S1: Obtain the voltage signal and current signal of the ultrasonic transducer at the current driving frequency; the initial value of the current driving frequency is the rated series resonance frequency of the ultrasonic transducer.

[0053] Start the megasonic power supply and output the current driving frequency. The initial value of the current driving frequency is the reference frequency. In this application, the reference frequency is set to the rated series resonance frequency of the ultrasonic transducer. The equivalent circuit diagram of the ultrasonic transducer is as Figure 3 shown.

[0054] Collect the voltage signal and current signal of the ultrasonic transducer at the current driving frequency. In this application, the frequency of the voltage signal is the same as that of the current signal. The expressions of the voltage signal and current signal are:

[0055]

[0056] where u(t) is the voltage signal, V m is the amplitude of the voltage signal, f0 is the frequency of the voltage signal and the frequency of the current signal, t is the current time, is the initial phase of the voltage signal, i(t) is the current signal, I m is the amplitude of the current signal, is the phase difference between the voltage signal and the current signal.

[0057] S2: Determine the phase difference between the voltage signal and the current signal according to the voltage signal and the current signal.

[0058] S2 specifically includes:

[0059] S21: Determine the first sine reference signal and the second sine reference signal.

[0060] The megasonic power supply transmits the collected voltage signal and current signal to the Field Programmable Gate Array (FPGA). The first sine reference signal and the second sine reference signal are generated inside the FPGA. The first sine reference signal and the second sine reference signal have the same amplitude and are orthogonal to each other, that is, the phase angle between the first sine reference signal and the second sine reference signal is 90°. The expressions of the first sine reference signal and the second sine reference signal are as follows:

[0061] RI(t) = cos(2πf1t).

[0062] RQ(t) = sin(2πf1t).

[0063] Wherein, RI(t) is the first sine reference signal, RQ(t) is the second sine reference signal, and f1 is the frequency of the first sine reference signal and the second sine reference signal, which is set within a range of 10% different from the rated series resonance frequency of the ultrasonic transducer.

[0064] S22: Determine the active power and reactive power according to the voltage signal, current signal, first sine reference signal, and second sine reference signal.

[0065] Multiply the collected voltage signal u(t) and current signal i(t) by the first sine reference signal RI(t) and the second sine reference signal RQ(t) respectively in the FPGA to obtain the following formula:

[0066]

[0067] Wherein, u1(t) is the result of multiplying the voltage signal by the first sine reference signal, u2(t) is the result of multiplying the voltage signal by the second sine reference signal, i1(t) is the result of multiplying the current signal by the first sine reference signal, and i2(t) is the result of multiplying the current signal by the second sine reference signal.

[0068] Use low-pass filters to filter u1(t), u2(t), i1(t), and i2(t) respectively to remove the sum-frequency signal and high-frequency noise. The sum-frequency signal is the component part of the frequency (f0 + f1), and retain the low-frequency (f0 + f1) signal. The filtered signals are y u1 (t), y u2 (t), y i1 (t), and y i2 (t), and the expressions are as follows:

[0069]

[0070] Wherein, y u1 (t) is the filtered signal of u1(t), that is, the result of filtering after multiplying the voltage signal by the first sine reference signal, and y u2 (t) is the filtered signal of u2(t), that is, the result of filtering after multiplying the voltage signal by the second sine reference signal, and y i1 (t) is the filtered signal of i1(t), that is, the result of filtering after multiplying the current signal by the first sine reference signal, and y i2 (t) is the filtered signal of i2(t), that is, the result of filtering after multiplying the current signal by the second sine reference signal.

[0071] S23: Determine the phase difference between the voltage signal and the current signal according to the active power and reactive power.

[0072] The active power, reactive power, and phase difference are all calculated within the FPGA. Among them, the phase difference between the voltage signal and the current signal is determined according to the following formula:

[0073]

[0074] Among them, is the phase difference between the voltage signal and the current signal, P is the active power, Q is the reactive power, V m is the amplitude of the voltage signal, I m is the amplitude of the current signal.

[0075] S3: Determine the current phase difference frequency according to the phase difference.

[0076] Judge whether the phase difference is within the preset phase difference threshold. If it is, the current driving frequency is the phase difference frequency; otherwise, based on the first preset step frequency, adjust the current driving frequency until the phase difference is within the preset phase difference threshold.

[0077] Specifically, take the phase difference threshold θ as the phase tracking standard. As Figure 4 shown, when the phase difference meets the preset phase difference threshold condition, that is , then the current driving frequency is near the zero-phase frequency, record the current driving frequency as the phase difference frequency, and initially determine the driving frequency range; when the phase difference does not meet the preset phase difference threshold condition, that is , continuously adjust the current driving frequency with the first preset step frequency Δf1. When the current signal leads the voltage signal, increase the driving frequency. When the current signal lags the voltage signal, decrease the driving frequency until the phase difference meets the preset phase difference threshold condition, that is, the phase difference is within the preset phase difference threshold.

[0078] S4: Judge whether the difference between the current phase difference frequency and the rated series resonance frequency is within the preset frequency threshold range. If it is, the current phase difference frequency is the preliminary screening frequency; otherwise, perform error compensation on the current phase difference frequency to update the current driving frequency until the difference between the current phase difference frequency and the rated series resonance frequency is within the preset frequency threshold range.

[0079] Specifically, if the difference between the current phase difference frequency and the rated series resonance frequency is within the preset frequency threshold τ, record the current phase difference frequency as the preliminary screening frequency; if the difference between the current phase difference frequency and the rated series resonance frequency is not within the preset frequency threshold τ, use an impedance analyzer to obtain the ratio κ of the zero-phase frequency of the ultrasonic transducer at no load to the rated series resonance frequency, and use it as the error compensation coefficient to calculate the phase difference frequency after error compensation until the difference between the current phase difference frequency and the rated series resonance frequency is within the preset frequency threshold τ. Determine the phase difference frequency after error compensation according to the following formula:

[0080]

[0081] κ = f r / f s ;

[0082] where f drive is the phase difference frequency after error compensation, f r * is the phase difference frequency, κ is the error compensation coefficient, f s is the rated series resonance frequency, f r is the zero-phase frequency.

[0083] S5: At the preliminary screening frequency, based on the second preset step frequency, adjust the driving frequency of the megasonic power supply, collect the power of the ultrasonic transducer at different driving frequencies, search for each power, and determine the maximum power of the ultrasonic transducer; the driving frequency corresponding to the maximum power is the optimized resonance frequency.

[0084] Specifically, after compensating for the phase difference frequency and determining the preliminary screening frequency, the driving frequency emitted by the megasonic power supply is near the rated series resonance frequency. Further, use the second preset step frequency to precisely adjust the driving frequency. The second preset step frequency is less than the first preset step frequency. The process of determining the maximum power of the ultrasonic transducer includes:

[0085] Judge whether the power of the ultrasonic transducer at time k satisfies the formula |(P(k) - P(k - 1)) / P(k - 1)| < ε; if so, the power of the ultrasonic transducer at time k is the maximum power, and the megasonic system is in the best resonance state. Otherwise, adjust the driving frequency according to the differential value dP of the power with respect to the driving frequency. When dP is negative, lower the driving frequency. When dP is positive, raise the driving frequency until the best resonance state is searched, that is, until the power of the ultrasonic transducer satisfies the formula |(P(k) - P(k - 1)) / P(k - 1)| < ε.

[0086] where P(k) is the power of the ultrasonic transducer at time k, P(k - 1) is the power of the ultrasonic transducer at time k - 1, and ε is the preset power threshold.

[0087] S6: Adjust the driving frequency of the megasonic power supply to the optimized resonance frequency.

[0088] Send the driving frequency corresponding to the searched maximum power, i.e., the optimized resonance frequency, to a Direct Digital Synthesis (DDS) module to generate a Pulse-Width Modulation (PWM) driving signal, providing a suitable control signal for driving the full-bridge inverter switching tubes subsequently.

[0089] After being amplified by a driving chip, the PWM driving signal drives the full-bridge inverter switching tubes in the megasonic power supply to generate high-frequency alternating current, providing a stable excitation power supply for the ultrasonic transducer and meeting the working requirements of the megasonic system.

[0090] In an exemplary embodiment, the frequency of an ultrasonic transducer of the same model is tracked respectively by using the resonance frequency tracking method of the megasonic power supply in this application and the traditional frequency tracking method. The rated series resonance frequency of the ultrasonic transducer is 1 MHz. As Figure 5 shown, when using the resonance frequency tracking method of the megasonic power supply in this application, the active power of the megasonic power supply is 111.9 W; as Figure 6 shown, when using the traditional frequency tracking method, the active power of the megasonic power supply is 104.7 W. It can be seen that the resonance frequency tracking method provided in this application has higher efficiency; as Figure 7 shown, when connecting ultrasonic transducers with different rated series resonance frequencies, the active power of the solution in this application is greater than that of the traditional solution in all cases, further reflecting the superiority and high efficiency of this application.

[0091] This application overcomes the shortcomings in the prior art. After quickly tracking the phase difference frequency through a preset step frequency, it analyzes the ratio of the phase difference frequency to the rated series resonance frequency and performs error frequency compensation, making the phase difference frequency after error compensation, i.e., the pre-screened frequency, reach near the series resonance frequency. Further, it uses the second preset step frequency to track the maximum power point, thereby obtaining the optimized resonance frequency and achieving precise tracking of the resonance frequency. It solves the problem that the traditional phase-locked tracking scheme ignores the error between the series resonance frequency and the zero-phase frequency, resulting in incomplete resonance of the ultrasonic transducer, and further optimizes the tracking effect of the megasonic power supply.

[0092] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 8As shown in the figure. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store the resonance frequency tracking data of the megasonic power supply. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements a method for tracking the resonance frequency of a megasonic power supply.

[0093] Those skilled in the art can understand that Figure 8 the structure shown in the figure is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have a different component layout.

[0094] In an exemplary embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the steps in the above method embodiments are implemented.

[0095] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by the processor, the steps in the above method embodiments are implemented.

[0096] In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by the processor, the steps in the above method embodiments are implemented.

[0097] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0098] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0099] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0100] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0101] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the present application; at the same time, for those of ordinary skill in the art, according to the ideas of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A resonance frequency tracking method for a megasonic power supply, characterized in that, Including: For driving the ultrasonic transducer to work with an AC signal at any sub - ultrasonic power output driving frequency, Obtaining a voltage signal and a current signal of the ultrasonic transducer at the current driving frequency; the initial value of the current driving frequency is the rated series resonance frequency of the ultrasonic transducer; Determining a phase difference between the voltage signal and the current signal according to the voltage signal and the current signal; Determining the current phase - difference frequency according to the phase difference; Judging whether the difference between the current phase - difference frequency and the rated series resonance frequency is within a preset frequency threshold range. If so, the current phase - difference frequency is the preliminary screening frequency; otherwise, error compensation is performed on the current phase - difference frequency to update the current driving frequency until the difference between the current phase - difference frequency and the rated series resonance frequency is within the preset frequency threshold range; At the preliminary screening frequency, based on the second preset step - size frequency, adjusting the driving frequency of the sub - ultrasonic power supply, collecting the powers of the ultrasonic transducer at different driving frequencies, searching for each power, and determining the maximum power of the ultrasonic transducer; the driving frequency corresponding to the maximum power is the optimized resonance frequency; Adjusting the driving frequency of the sub - ultrasonic power supply to the optimized resonance frequency.

2. The resonance frequency tracking method of the megasonic power supply according to claim 1, characterized in that, The step of determining the phase difference between the voltage signal and the current signal according to the voltage signal and the current signal specifically includes: Determining a first sine reference signal and a second sine reference signal; the first sine reference signal and the second sine reference signal have the same amplitude and are orthogonal to each other; Determining the active power and the reactive power according to the voltage signal, the current signal, the first sine reference signal and the second sine reference signal; Determining the phase difference between the voltage signal and the current signal according to the active power and the reactive power.

3. The resonant frequency tracking method of the megasonic power supply according to claim 2, characterized in that Determining the phase difference according to the following formula: Among them, is the phase difference between the voltage signal and the current signal, P is the active power, Q is the reactive power, and y u1 (t) is the result of filtering after multiplying the voltage signal by the first sine reference signal, y u2 (t) is the result of filtering after multiplying the voltage signal by the second sine reference signal, y i1 (t) is the result of filtering after multiplying the current signal by the first sine reference signal, y i2 (t) is the result of filtering after multiplying the current signal by the second sine reference signal, V m is the amplitude of the voltage signal, I m is the amplitude of the current signal, and t is the current time.

4. The resonance frequency tracking method of the megasonic power supply according to claim 1, characterized in that, The step of determining the current phase - difference frequency according to the phase difference specifically includes: Judging whether the phase difference is within a preset phase - difference threshold. If so, the current driving frequency is the phase - difference frequency; otherwise, adjusting the current driving frequency based on the first preset step - size frequency until the phase difference is within the preset phase - difference threshold; where the first preset step - size frequency is greater than the second preset step - size frequency.

5. The resonant frequency tracking method of the megasonic power supply according to claim 1, characterized in that, Determining the phase - difference frequency after error compensation according to the following formula: κ = f r / f s ; Among them, f drive is the phase difference frequency after error compensation, is the phase difference frequency, κ is the error compensation coefficient, f s is the rated series resonance frequency, f r is the zero-phase frequency.

6. The resonant frequency tracking method of the megasonic power supply according to claim 1, characterized in that The process of determining the maximum power of the ultrasonic transducer includes: Judging whether the power of the ultrasonic transducer at the k - th moment satisfies the formula |(P(k)-P(k - 1)) / P(k - 1)|<ε; if so, the power of the ultrasonic transducer at the k - th moment is the maximum power; otherwise, adjusting the driving frequency according to the differential value of the power with respect to the driving frequency until the power of the ultrasonic transducer satisfies the formula |(P(k)-P(k - 1)) / P(k - 1)|<ε; Where, P(k) is the power of the ultrasonic transducer at the k - th moment, P(k - 1) is the power of the ultrasonic transducer at the (k - 1) - th moment, and ε is a preset power threshold.

7. The resonance frequency tracking method of the megasonic power supply according to claim 1, characterized in that, After adjusting the driving frequency of the sub - ultrasonic power supply to the optimized resonance frequency, it further includes: Determining a pulse - width modulation driving signal according to the optimized resonance frequency; Drive the megasonic power supply with the pulse width modulation drive signal to generate high-frequency alternating current; the high-frequency alternating current is used to power the ultrasonic transducer.

8. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the resonance frequency tracking method of the megasonic power supply according to any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the resonance frequency tracking method of the megasonic power supply according to any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the resonance frequency tracking method of the megasonic power supply according to any one of claims 1-7.

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