Piezoelectric ceramic driving device and driving method based on dynamic LC matching

Abstract

The invention relates to the technical field of circuit adjustment, and provides a dynamic LC matching piezoelectric ceramic driving device and method, and the device comprises a power module, a filtering module, and a dynamic LC matching module. The power supply module is used for outputting a square wave signal; the filtering module is used for converting the square wave signal into a sine wave signal; and the dynamic LC matching module is connected with the piezoelectric ceramic and is used for adjusting the impedance of the dynamic LC matching module according to the impedance of the piezoelectric ceramic, so that the impedance in the transmission link is stable. According to the scheme, the parameters of the matching network can be adaptively adjusted according to the change of the piezoelectric ceramics, so that each part of the system is always in a resonance state, the power loss and heat generation in a circuit are reduced, and the service life of the circuit and equipment is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit regulation, and in particular to a driving device and a driving method of a piezoelectric ceramic with dynamic LC matching. Background Art

[0002] High-power piezoelectric ceramics are widely used in many fields, such as ultrasonic motors, high-voltage generators, ultrasonic scalpels, and atomization drug delivery devices. Therefore, improving the output power is an important research direction of piezoelectric ceramic drive systems.

[0003] The commonly used power boosting method at present is the impedance matching method, whose main purpose is to match the output impedance of the power supply with the equivalent impedance by reasonably transforming the load impedance, so as to ensure that power can be effectively transmitted from the power supply to the load.

[0004] The traditional solution is static matching, which requires measuring the impedance of the piezoelectric ceramic and the output impedance of the power supply in advance, determining the parameters of the impedance matching network based on the measurement results, and configuring the matching network to ensure that the piezoelectric ceramic is in a resonant state. During the entire working process, the parameters of the matching network cannot be adjusted.

[0005] However, the impedance of piezoelectric ceramics will change when the output power is high, and will also change when the piezoelectric ceramics are continuously working for a long time and the temperature of the working environment changes. If static matching is used, the matching will fail when the impedance of the piezoelectric ceramics changes, resulting in a decrease in power transmission efficiency.

[0006] Therefore, there is an urgent need to develop a dynamic LC matching piezoelectric ceramic driving device and driving method, which can adaptively adjust the parameters of the matching network according to the changes of the piezoelectric ceramic, so that all components of the system are always in a resonant state, reduce power loss and heat generation in the circuit, and thus extend the service life of the circuit and equipment.

[0007] The above information disclosed in the Background section is only for enhancement of understanding of the background of the present application and therefore it may contain information that does not constitute the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0008] The main purpose of the present invention is to overcome the problem of decreased power transmission of piezoelectric ceramics and to provide a driving device and a driving method for piezoelectric ceramics with dynamic LC matching, which can adaptively adjust the parameters of the matching network according to the changes of the piezoelectric ceramics, so that the various components of the system are always in a resonant state, reducing power loss and heat generation in the circuit, thereby extending the service life of the circuit and the equipment.

[0009] To achieve the above-mentioned purpose, the first aspect of the present invention provides a dynamic LC matching piezoelectric ceramic driving device, comprising: a power supply module, a filter module and a dynamic LC matching module;

[0010] The power supply module is used to output a square wave signal;

[0011] The filtering module is used to convert the square wave signal into a sine wave signal;

[0012] The dynamic LC matching module is connected to the piezoelectric ceramic and is used to adjust the impedance of the dynamic LC matching module according to the impedance of the piezoelectric ceramic, so that the impedance in the transmission link is stable.

[0013] According to an exemplary embodiment of the present invention, the power module includes a main control system, a driving module, a direct current and a half-bridge MOS tube;

[0014] The main control system is connected to the driving module and is used to generate a PWM wave with adjustable frequency and duty cycle, which is provided to the driving module for power amplification;

[0015] The driving module is connected to the half-bridge MOS tube and is used to use the PWM wave after power amplification to control the switch of the half-bridge MOS tube;

[0016] The DC power supply is connected to the half-bridge MOS tube and is used as an energy source for the switch circuit to provide electrical energy for the inversion of the Houji half-bridge MOS tube;

[0017] The half-bridge MOS tube is used to convert the DC power supply into a square wave signal.

[0018] According to an exemplary embodiment of the present invention, the filtering module adopts a Butterworth low-pass filter.

[0019] According to an exemplary embodiment of the present invention, the Butterworth low-pass filter comprises: a first filter inductor, a second filter inductor, a third filter inductor, a first filter capacitor and a second filter capacitor;

[0020] The first filter inductor includes a first end and a second end, the second filter inductor includes a first end and a second end, the third filter inductor includes a first end and a second end, the first filter capacitor includes a first end and a second end, and the second filter capacitor includes a first end and a second end;

[0021] The first end of the first filter inductor is connected to the power module, the second end of the first filter inductor is connected to the first end of the second filter inductor and the first end of the first filter capacitor; the second end of the first filter capacitor is grounded;

[0022] The second end of the second filter inductor is connected to the first end of the second filter capacitor and the first end of the third filter inductor; the second end of the second filter capacitor is grounded;

[0023] The second end of the third filter inductor is connected to the dynamic LC matching module.

[0024] According to an example embodiment of the present invention, the dynamic LC matching module includes: a sampling module, a controller, and an adjustment module; the sampling module is used to collect the circuit, voltage and phase difference of the piezoelectric ceramic and feed back to the controller; the controller calculates the values ​​of inductance and capacitance that need to be adjusted according to the current, voltage and phase difference of the piezoelectric ceramic; the adjustment module adjusts the inductance and capacitance according to the values ​​of the inductance and capacitance that need to be adjusted.

[0025] According to an exemplary embodiment of the present invention, the controller adopts DSP; the regulating module includes a motor, a relay array, a filter, an adjustable inductor and an adjustable capacitor; the sampling module is a current and voltage acquisition module;

[0026] The DSP is connected to the current and voltage acquisition module, the motor, and the relay array to calculate the inductance and capacitance values ​​that need to be adjusted, and instruct the motor to adjust the adjustable inductance and the relay array to adjust the adjustable capacitance;

[0027] The current and voltage acquisition module is used to collect the voltage, current and phase difference of the piezoelectric ceramic;

[0028] The filter includes a first end and a second end, the circuit voltage acquisition module includes a first end and a second end, the adjustable inductor includes a first end, a second end and an adjustment end, and the adjustable capacitor includes a first end, a second end and an adjustment end;

[0029] The motor is connected to the adjustment end of the adjustable inductor to adjust the value of the inductor;

[0030] The relay array is connected to the adjustment end of the adjustable capacitor to adjust the value of the capacitor;

[0031] The first end of the filter is connected to the first end of the adjustable inductor, and the second end of the filter is connected to the second end of the adjustable capacitor and the second end of the current and voltage acquisition module;

[0032] The second end of the adjustable inductor is connected to the first end of the adjustable capacitor and the first end of the current and voltage acquisition module.

[0033] According to an example embodiment of the present invention, the adjustable capacitor includes seven capacitors, the relay array includes seven relays, each capacitor is connected to a relay, and the capacitances of the seven capacitors are 200pF, 390pF, 620pF, 820pF, 1000pF, 2000pF, and 4000pF, respectively.

[0034] As a second aspect of the present invention, the present invention provides a method for driving a piezoelectric ceramic with dynamic LC matching, using the driving device of the piezoelectric ceramic with dynamic LC matching, comprising the following steps:

[0035] S1: Generate and output square wave signal;

[0036] S2: Convert the square wave signal into a sine wave signal;

[0037] S3: The impedance of the dynamic LC matching module is adjusted according to the impedance of the piezoelectric ceramic, so that the impedance in the transmission link is stable.

[0038] According to an exemplary embodiment of the present invention, in step S3, adjusting the impedance of the dynamic LC matching module according to the impedance of the piezoelectric ceramic includes:

[0039] Obtain the voltage, current and phase difference of piezoelectric ceramics;

[0040] Calculate the required inductance and capacitance based on the voltage, current and phase difference of the piezoelectric ceramic;

[0041] The motor adjusts the inductance to the required inductance, and the relay array adjusts the capacitance to the required capacitance.

[0042] According to an exemplary embodiment of the present invention, the required inductance and capacitance are calculated based on the voltage, current and phase difference of the piezoelectric ceramic using the following formula:

[0043]

[0044] Among them, Z eq It represents the overall equivalent impedance of the dynamic LC matching module and the piezoelectric ceramic; Z L Represents the impedance of piezoelectric ceramics; R L is the real part of the impedance of the piezoelectric ceramic; X L is the imaginary part of the impedance of the piezoelectric ceramic;

[0045] Z L =R L +iX L ;ω represents the angular frequency of the piezoelectric ceramic AC power supply; C P Indicates the required capacitance; L P Indicates the required inductance.

[0046] This solution connects a fifth-order Butterworth filter after the switching power supply that outputs the square wave signal to achieve filtering, and then inserts a matching network composed of capacitor and inductor elements between the filter and the piezoelectric ceramic. By adjusting the size of the inductor and capacitor in the network, the impedance of the piezoelectric ceramic can be transformed into the characteristic impedance of the filter to reduce the impedance mutation in the transmission link and reduce the reflection of energy. Ideally, these capacitors and inductors only play the role of impedance conversion without consuming electrical power. This solution forms a closed-loop system, adjusts the parameters of the matching network in real time according to the feedback signal of the circuit, maintains the optimal performance of the circuit, keeps all components of the system in a resonant state, and ensures that the signal or electric energy can be transmitted without reflection or with maximum power during the transmission process, thereby improving the overall performance of the system. Dynamic matching reduces power loss and heat generation in the circuit by optimizing the matching parameters, thereby extending the service life of the circuit and equipment. This solution conveniently implements this process through adjustable inductors and adjustable capacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The above and other objects, features and advantages of the present application will become more apparent by describing in detail the exemplary embodiments thereof with reference to the accompanying drawings. The accompanying drawings described below are only some embodiments of the present application, and it is clear to a person skilled in the art that other accompanying drawings can be obtained from these accompanying drawings without creative effort.

[0048] Figure 1 The structure of a piezoelectric ceramic driving device with dynamic LC matching is schematically shown.

[0049] Figure 2 The connection relationship diagram between the filter module and the front and rear components is schematically shown.

[0050] Figure 3 The structure diagram of the dynamic LC matching module is schematically shown.

[0051] Figure 4 The structure of the adjustable capacitor is schematically shown.

[0052] Figure 5 The structure of the adjustable inductor is schematically shown.

[0053] Figure 6 The following is a schematic diagram showing the steps of a method for driving a piezoelectric ceramic with dynamic LC matching.

[0054] Among them, 1 is a power module, 2 is a filter module, 3 is a dynamic LC matching module, 31 is a skeleton, 32 is a magnetic core, 33 is a slide, 34 is a coupling, 35 is a lead screw, and 4 is a piezoelectric ceramic. DETAILED DESCRIPTION

[0055] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0056] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0057] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0058] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0059] It should be understood that although the terms first, second, third, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another component. Therefore, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of the present application. As used herein, the term "and / or" includes any one of the associated listed items and all combinations of one or more.

[0060] Those skilled in the art will appreciate that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present application, and therefore cannot be used to limit the scope of protection of the present application.

[0061] According to a first specific embodiment of the present invention, the present invention provides a driving device of a piezoelectric ceramic with dynamic LC matching, such as Figure 1 As shown, it includes: a power supply module 1, a filter module 2 and a dynamic LC matching module 3.

[0062] The power of high-power piezoelectric ceramics is generally above 600W. Since the impedance characteristics of piezoelectric ceramics under low-power working conditions do not change as drastically as in high-power application scenarios, other static LC matching methods can also achieve impedance matching to a certain extent. Therefore, there is no need to dynamically adjust the capacitance and inductance values ​​for impedance matching. Therefore, this solution is more suitable for high-power piezoelectric ceramics.

[0063] The power module 1 is used to output a square wave signal. Figure 1 As shown, the power module includes a main control system, a driving module, a direct current and a half-bridge MOS tube. The main control system is connected to the driving module to generate a PWM wave with adjustable frequency and duty cycle, which is provided to the driving module for power amplification. The driving module is connected to the half-bridge MOS tube to use the PWM wave after power amplification to control the switch of the half-bridge MOS tube. The direct current power supply is connected to the half-bridge MOS tube to serve as an energy source for the switching circuit and provide electrical energy for the inversion of the Houji half-bridge MOS tube. The half-bridge MOS tube is used to convert the direct current power supply into a square wave signal.

[0064] The filter module 2 is connected to the half-bridge MOS tube of the power module 1 and is used to convert the square wave signal into a sine wave signal. The filter module adopts a Butterworth low-pass filter. Figure 2 As shown, the Butterworth low-pass filter includes: a first filter inductor L1, a second filter inductor L2, a third filter inductor L3, a first filter capacitor C1 and a second filter capacitor C2.

[0065] The first filter inductor L1 includes a first end and a second end, the second filter inductor L2 includes a first end and a second end, the third filter inductor L3 includes a first end and a second end, the first filter capacitor C1 includes a first end and a second end, and the second filter capacitor C2 includes a first end and a second end.

[0066] The first end of the first filter inductor L1 is connected to the power module 1, and the second end of the first filter inductor L1 is connected to the first end of the second filter inductor L1 and the first end of the first filter capacitor C1. The second end of the first filter capacitor C1 is grounded.

[0067] The second end of the second filter inductor L2 is connected to the first end of the second filter capacitor C2 and the first end of the third filter inductor L3. The second end of the second filter capacitor C2 is grounded.

[0068] The second end of the third filter inductor L3 is connected to the dynamic LC matching module 3 .

[0069] Figure 2In the figure, Zeq represents the total impedance of the dynamic LC matching module 3 and the piezoelectric ceramic 4, which refers to the equivalent impedance from the LC impedance transformation network (dynamic LC matching module 3) to the piezoelectric ceramic 4 end, including a first end and a second end, the first end is connected to the second end of the third filter inductor L3, and the second end is grounded. Rs is the internal resistance of the power supply (here refers to the internal resistance of the DC power supply), including a first end and a second end, the first end is connected to the power module 1, and the second end is connected to the first end of the first filter inductor L1.

[0070] This solution uses a fifth-order Butterworth filter. The performance indicators of the Butterworth low-pass filter mainly include the cutoff frequency f c and characteristic impedance z 0 The cut-off frequency can be more than twice the fundamental frequency of the power signal. As for the characteristic impedance, it should be appropriately selected according to the output capacity of the power supply to avoid excessive output current of the power supply. Then, the piezoelectric ceramic impedance is transformed into the characteristic impedance of the filter through the LC dynamic matching network. When the characteristic impedance of the filter matches the piezoelectric ceramic impedance, the passband is smoothest and the return loss in the passband is small.

[0071] As a preferred implementation, the first filter inductor L1 is 0.61803*K / MH, the second filter inductor L2 is 2*K / MH, the third filter inductor L3 is 0.61803*K / MH, the first filter capacitor C1 is 1.61803 / (K*M)F, and the second filter capacitor C2 is 1.61803 / (K*M)F.

[0072] When the ratio of the output voltage to the Laplace transform of the input voltage of the Butterworth low-pass filter is written in the form of a transfer function, it should satisfy the Butterworth polynomial. The Butterworth polynomial has a certain coefficient and zero-pole distribution. Only by satisfying this coefficient can the advantages mentioned above (passband flatness, etc.) be achieved. Then we can realize the inductance and capacitance values ​​in the circuit elements according to the coefficients of the Butterworth polynomial. In actual implementation, two factors should be considered, the cutoff frequency and the characteristic impedance. The characteristic impedance should be equal to the internal resistance of the front-stage power supply (Rs) and the overall equivalent impedance (Zeq) of the back stage connected to this filter. This can reduce the reflection of energy at the discontinuity of impedance. In actual engineering applications, staff generally directly look up the table to read the values ​​of each inductor and capacitor in the fifth-order Butterworth low-pass filter realized by LC components, which is the source of the coefficients such as 1.61803 in the formula.

[0073] Among them, K and M are parameters.

[0074]

[0075] The cutoff frequency and characteristic impedance of such a filter are:

[0076] Cutoff frequency

[0077] Characteristic impedance Z0=K(Ω)

[0078] The above two indicators can be used to determine the values ​​of parameters K and M, and then the values ​​of each component.

[0079] The source end internal resistance of the filter and the piezoelectric ceramic impedance should be equal to the characteristic impedance of the filter, otherwise it will cause oscillation in the passband, too much return loss, and too little insertion loss.

[0080] like Figure 1 As shown, the dynamic LC matching module 3 is connected to the piezoelectric ceramic 4 and is used to adjust the impedance of the dynamic LC matching module 3 according to the impedance of the piezoelectric ceramic 4 so that the impedance in the transmission link is stable.

[0081] like Figure 1 As shown, the dynamic LC matching module includes: a sampling module, a controller, and an adjustment module. The sampling module is used to collect the current, voltage, and phase difference of the piezoelectric ceramic and feed it back to the controller. The controller calculates the values ​​of the inductance and capacitance that need to be adjusted according to the current, voltage, and phase difference of the piezoelectric ceramic. The adjustment module adjusts the inductance and capacitance according to the values ​​of the inductance and capacitance that need to be adjusted.

[0082] like Figure 3 As shown, the controller uses DSP. The regulation module includes a motor, a relay array, a filter, an adjustable inductor and an adjustable capacitor. The sampling module is a current and voltage acquisition module.

[0083] The DSP is connected with the current and voltage acquisition module, the motor, and the relay array to calculate the inductance and capacitance values ​​that need to be adjusted, and instruct the motor to adjust the adjustable inductance and instruct the relay array to adjust the adjustable capacitance.

[0084] The current and voltage acquisition module is used to acquire the voltage, current and phase difference of the piezoelectric ceramic 4 .

[0085] The filter includes a first end and a second end, the circuit voltage acquisition module includes a first end and a second end, the adjustable inductor includes a first end, a second end and an adjustment end, and the adjustable capacitor includes a first end and a second end.

[0086] The motor is connected to the adjustment end of the adjustable inductor to adjust the value of the inductor.

[0087] The relay array is connected to one end of the adjustable capacitor to adjust the value of the capacitor.

[0088] The first end of the filter is connected to the first end of the adjustable inductor, and the second end of the filter is connected to the second end of the adjustable capacitor and the second end of the current and voltage acquisition module.

[0089] The second end of the adjustable inductor is connected to the first end of the adjustable capacitor and the first end of the current and voltage acquisition module.

[0090] By collecting the voltage, current and phase difference across the piezoelectric ceramic 4 and transmitting them to the DSP, the DSP calculates the capacitance and inductance that need to be adjusted, and then the motor and relay array adjust the inductance and capacitance respectively.

[0091] like Figure 4 As shown, the adjustable capacitor includes seven capacitors, the relay array includes seven relays, each capacitor is connected to a relay, and the capacitance values ​​of the seven capacitors are 200pF, 390pF, 620pF, 820pF, 1000pF, 2000pF, and 4000pF, respectively.

[0092] The adjustable capacitor is controlled by seven relays, which respectively control the on and off of seven capacitors. Capacitors with different capacitance values ​​can be combined to obtain more different capacitance values. The capacitance adjustment range is 200pF to 9030pF, and the adjustment accuracy is approximately 200pF.

[0093] like Figure 4 As shown, Figure 4 The connection relationship between the relay array and the adjustable capacitor is shown in FIG. Figure 4 It includes a relay array, an adjustable capacitor, a first connector U9, a second connector U4, a third connector U5, a fourth connector U7, and a fifth connector U8. The relay array includes a first relay K1, a second relay K2, a third relay K3, a fourth relay K4, a fifth relay K5, a sixth relay K6, and a seventh relay K7. The adjustable capacitor includes a first capacitor C3, a second capacitor C4, a third capacitor C5, a fourth capacitor C6, a fifth capacitor C7, a sixth capacitor C8, and a seventh capacitor C9.

[0094] Each relay includes a first end, a second end, a third end and a fourth end. The second connector U4, the third connector U5, the fourth connector U7 and the fifth connector U8 each include four ports, namely the first end, the second end, the third end and the fourth end, and the four ports are interconnected. Each capacitor includes a first end and a second end. The first end of the adjustable capacitor is the third connector U5 and the fifth connector U8; the second end is the second connector U4 and the fourth connector U7, and one of them can be selected to connect to the circuit. The relay array is connected to the first end of the adjustable capacitor.

[0095] The first connector U9 includes 8 ports, each of which is connected to the first end of a relay. The second end of each relay is connected to the fourth end of the third connector U5 and the fifth connector U8. The third ends of the seven relays are connected to the first end of a capacitor, and the second end of each capacitor is connected to the fourth end of the second connector U4 and the fourth connector U7. The fourth end of each relay is connected to the positive pole of the power supply, and the power supply voltage is 5V.

[0096] The capacitance values ​​of the first capacitor to the seventh capacitor are 200pF, 390pF, 620pF, 820pF, 1000pF, 2000pF, and 4000pF, respectively.

[0097] Since the capacitance of a series of capacitors changes evenly during dynamic adjustment only when the value of the latter stage is exactly twice that of the former stage (that is, the capacitance of this series of capacitors is a geometric progression with a common ratio of 2), there are actually no capacitors on the market that change with a rule of 2, so we can only approximately select a series of capacitors that change with a rule of multiples of 2. Considering that inserting a capacitor with medium capacitance between two adjacent capacitors may cause uneven capacitance changes, it can improve the resolution of the variable capacitor to a certain extent. Therefore, a capacitor of 820pF is inserted between 620pF and 1000pF, and finally a series of capacitance values ​​becomes 200pF, 390pF, 620pF, 820pF, 1000pF, 2000pF, and 4000pF.

[0098] like Figure 5 As shown, the main part of the adjustable inductor includes a skeleton 31, two magnetic cores 32, a slide 33, a coupling 34 and a screw 35. The skeleton 31 is used to wind the copper wire and is fixed at the center of the slide 33. The magnetic core 32 is a movable EER42 type ferrite core, which is arranged at both ends of the skeleton 31. The slide 33 is a bidirectional slide, and the two ends of the slide 33 can slide outward. The two magnetic cores 32 are respectively fixed at the two ends of the slide 33. The coupling 34 is fixed at both ends of the screw 35 and is connected to the motor to drive the screw 35 to rotate. The screw rod 35 is inserted from one end of the slide 33 and is passed out from the other end of the slide 33. The screw rod 35 is a threaded structure. The connection between the slide 33 and the screw rod 35 is adapted to the threaded structure of the screw rod 35. Under the drive of the motor, the screw rod 35 rotates, driving the two ends of the slide 33 to slide outward or inward (middle), so that the magnetic core 32 is inserted into or withdrawn from the skeleton 31, so as to achieve the purpose of changing the magnetic permeability of the medium in the skeleton 31. When the magnetic core 32 is inserted into the skeleton 31, the magnetic permeability of the center medium increases, and the inductance value of the copper wire wound on the skeleton 31 will increase; when the skeleton 31 is withdrawn, the magnetic permeability of the center medium decreases, and the inductance value of the copper wire wound on the skeleton 31 will decrease.

[0099] As a preferred implementation, the first connector U9 uses ZX-XH2-54-8PWZ, and the second connector U4, the third connector U5, the fourth connector U7, and the fifth connector U8 use T34001.

[0100] This solution consists of a power module 1, a filter module 2, and a dynamic LC matching module 3. The power module 1 converts the DC power supply into a square wave through the topology of a half-bridge MOS. The filter module 2 allows specific frequency components in the signal to pass through while reducing or eliminating other frequency components, converting the square wave into a sine wave. The impedance of the piezoelectric ceramic 4 is then transformed to the characteristic impedance of the filter module through the dynamic LC matching module 3. Since the impedance of the piezoelectric ceramic 4 may change during operation, this solution collects the input voltage, input current, and phase difference of the piezoelectric ceramic 4 through a sampling module, calculates its impedance, and dynamically adjusts the motor and relay through a controller to change the values ​​of the matching inductor and the matching capacitor.

[0101] According to a second specific embodiment of the present invention, the present invention provides a method for driving a piezoelectric ceramic with dynamic LC matching, using the driving device of the piezoelectric ceramic with dynamic LC matching according to the first specific embodiment, such as Figure 6 As shown, the following steps are included:

[0102] S1: Generates and outputs a square wave signal.

[0103] This step is performed by power module 1.

[0104] S2: Convert the square wave signal into a sine wave signal.

[0105] This step is performed by filtering module 2.

[0106] S3: The impedance of the dynamic LC matching module is adjusted according to the impedance of the piezoelectric ceramic, so that the impedance in the transmission link is stable.

[0107] This step is performed by the dynamic LC matching module 3.

[0108] The impedance of the dynamic LC matching module is adjusted according to the impedance of the piezoelectric ceramic:

[0109] Obtain the voltage, current and phase difference of piezoelectric ceramics;

[0110] Calculate the required inductance and capacitance based on the voltage, current and phase difference of the piezoelectric ceramic;

[0111] The motor adjusts the inductance to the required inductance, and the relay array adjusts the capacitance to the required capacitance.

[0112] For the impedance Z of piezoelectric ceramics L , assuming that the real part of the impedance is R L , the imaginary part of impedance is X L, so Z L =R L +iX L , then the equivalent impedance Z of the LC matching circuit and the piezoelectric ceramic eq for:

[0113]

[0114] Among them, ω is the angular frequency of the AC power supply. The above formula can be transformed into:

[0115]

[0116] Therefore, the required inductance and capacitance are calculated based on the voltage, current and phase difference of the piezoelectric ceramic using the following formula:

[0117]

[0118] Among them, Z eq It represents the overall equivalent impedance of the dynamic LC matching module and the piezoelectric ceramic; Z L Represents the impedance of piezoelectric ceramics; R L is the real part of the impedance of the piezoelectric ceramic; X L is the imaginary part of the impedance of the piezoelectric ceramic;

[0119] Z L =R L +iX L ; ω represents the angular frequency of the piezoelectric ceramic AC power supply. The AC power supply is a sinusoidal AC power supply obtained by inverting the DC power supply into a square wave AC power and then filtering it through a filter; C P Indicates the required capacitance; L P Indicates the required inductance.

[0120] The ADC (analog-to-digital converter, used to collect analog quantities) collects and obtains the voltage, current and phase difference at the input end of the piezoelectric ceramic, and the DSP calculates the impedance Z of the piezoelectric ceramic. L , Z L Equal to the ratio of voltage phasor to current phasor, Z L It can also be written as Z L =R L +iX L After cascading with the LC network, the equivalent impedance Z seen from the LC impedance transformation network (dynamic LC matching module 3) to the piezoelectric ceramic 4 can be obtained. eq , we adjust the L in the LC network p , C p The value of Z eq The imaginary part is 0 and the real part is an adjustable value, so that the impedance of the piezoelectric ceramic can be transformed to any desired impedance. In this application, it is transformed to the characteristic impedance of the filter.

[0121] Therefore, we only need to adjust L P and C P The value of Z eq The imaginary part is 0, and the real part is the characteristic impedance of the filter.

[0122] Static matching uses instruments to test the impedance of each component of the system before the circuit works, and calculates the parameters of the matching circuit accordingly. However, during the operation of each component of the system, its impedance characteristics may change due to temperature, load changes, environmental factors, etc. At this time, static matching cannot be adjusted in time, resulting in circuit mismatch. Dynamic matching, on the other hand, forms a closed-loop system and adjusts the parameters of the matching network in real time according to the feedback signal of the circuit, so that each component of the system is always in a resonant state. In a complex and changing environment, static matching may not be able to adapt to various changes, resulting in a decrease in circuit performance. Dynamic matching can adjust the matching parameters in real time according to changes in the environment to maintain the best performance of the circuit. Dynamic matching can ensure that signals or electrical energy are transmitted without reflection or with maximum power during transmission, thereby improving the overall performance of the system.

[0123] This solution connects a fifth-order Butterworth filter to the switching power supply that outputs the square wave signal to achieve filtering, and then inserts a matching network composed of capacitor and inductor elements between the filter and the piezoelectric ceramic. By adjusting the size of the inductor and capacitor in the network, the impedance of the piezoelectric ceramic can be transformed into the characteristic impedance of the filter to reduce the impedance mutation in the transmission link and reduce the reflection of energy. Ideally, these capacitors and inductors only play the role of impedance conversion without consuming electrical power. This solution forms a closed-loop system, adjusts the parameters of the matching network in real time according to the feedback signal of the circuit, maintains the optimal performance of the circuit, keeps the various components of the system in a resonant state, and ensures that the signal or electric energy can be transmitted without reflection or with maximum power during the transmission process, thereby improving the overall performance of the system. Dynamic matching reduces power loss and heat generation in the circuit by optimizing the matching parameters, thereby extending the service life of the circuit and equipment. This solution conveniently implements this process through adjustable inductors and adjustable capacitors. In addition, this solution can also be used in industrial applications such as megasonic generators.

[0124] The exemplary embodiments of the present invention are specifically shown and described above. It should be understood that the present invention is not limited to the detailed structure, configuration or implementation method described herein; on the contrary, the present invention is intended to cover various modifications and equivalent configurations included in the spirit and scope of the appended claims.

Claims

1. A piezoelectric ceramic driving device with dynamic LC matching, characterized in that: include: Power module, filter module and dynamic LC matching module; The power supply module is used to output a square wave signal; The filtering module is used to convert the square wave signal into a sine wave signal; The dynamic LC matching module is connected to the piezoelectric ceramic and is used to adjust the impedance of the dynamic LC matching module according to the impedance of the piezoelectric ceramic, so that the impedance in the transmission link is stable.

2. The dynamic LC matching piezoelectric ceramic driving device according to claim 1, characterized in that: The power module includes a main control system, a drive module, a DC power supply and a half-bridge MOS tube; The main control system is connected to the driving module and is used to generate a PWM wave with adjustable frequency and duty cycle, which is provided to the driving module for power amplification; The driving module is connected to the half-bridge MOS tube and is used to use the PWM wave after power amplification to control the switch of the half-bridge MOS tube; The DC power supply is connected to the half-bridge MOS tube and is used as an energy source for the switch circuit to provide electrical energy for the inversion of the Houji half-bridge MOS tube; The half-bridge MOS tube is used to convert the DC power supply into a square wave signal.

3. The dynamic LC matching piezoelectric ceramic driving device according to claim 1, characterized in that: The filtering module adopts a Butterworth low-pass filter.

4. The dynamic LC matching piezoelectric ceramic driving device according to claim 3, characterized in that: The Butterworth low-pass filter comprises: a first filter inductor, a second filter inductor, a third filter inductor, a first filter capacitor and a second filter capacitor; The first filter inductor includes a first end and a second end, the second filter inductor includes a first end and a second end, the third filter inductor includes a first end and a second end, the first filter capacitor includes a first end and a second end, and the second filter capacitor includes a first end and a second end; The first end of the first filter inductor is connected to the power module, the second end of the first filter inductor is connected to the first end of the first filter capacitor and the first end of the second filter inductor; the second end of the first filter capacitor is grounded; The second end of the second filter inductor is connected to the first end of the second filter capacitor and the first end of the third filter inductor; the second end of the second filter capacitor is grounded; The second end of the third filter inductor is connected to the dynamic LC matching module.

5. The dynamic LC matching piezoelectric ceramic driving device according to claim 1, characterized in that: The dynamic LC matching module includes: a sampling module, a controller, and an adjustment module; the sampling module is used to collect the current, voltage and phase difference of the piezoelectric ceramic and feed back to the controller; the controller calculates the values ​​of inductance and capacitance that need to be adjusted according to the current, voltage and phase difference of the piezoelectric ceramic; and the adjustment module adjusts the inductance and capacitance according to the values ​​of the inductance and capacitance that need to be adjusted.

6. The dynamic LC matching piezoelectric ceramic driving device according to claim 1, characterized in that: The controller adopts DSP; the regulating module includes a motor, a relay array, a filter, an adjustable inductor and an adjustable capacitor; the sampling module is a current and voltage acquisition module; The DSP is connected to the current and voltage acquisition module, the motor, and the relay array, and is used to calculate the values ​​of the inductance and capacitance that need to be adjusted, and instruct the motor to adjust the adjustable inductance and instruct the relay array to adjust the adjustable capacitance; The current and voltage acquisition module is used to collect the voltage, current and phase difference of the piezoelectric ceramic; The filter includes a first end and a second end, the circuit voltage acquisition module includes a first end and a second end, the adjustable inductor includes a first end, a second end and an adjustment end, and the adjustable capacitor includes a first end, a second end and an adjustment end; The motor is connected to the adjustment end of the adjustable inductor to adjust the value of the inductor; The relay array is connected to the adjustment end of the adjustable capacitor to adjust the value of the capacitor; The first end of the filter is connected to the first end of the adjustable inductor, and the second end of the filter is connected to the second end of the adjustable capacitor and the second end of the current and voltage acquisition module; The second end of the adjustable inductor is connected to the first end of the adjustable capacitor and the first end of the current and voltage acquisition module.

7. The dynamic LC matching piezoelectric ceramic driving device according to claim 6, characterized in that: The adjustable capacitor includes seven capacitors, the relay array includes seven relays, each capacitor is connected to a relay, and the capacitance values ​​of the seven capacitors are 200pF, 390pF, 620pF, 820pF, 1000pF, 2000pF, and 4000pF respectively.

8. A method for driving a piezoelectric ceramic with dynamic LC matching, using the driving device for a piezoelectric ceramic with dynamic LC matching according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Generate and output square wave signal; S2: Convert the square wave signal into a sine wave signal; S3: The impedance of the dynamic LC matching module is adjusted according to the impedance of the piezoelectric ceramic, so that the impedance in the transmission link is stable.

9. The driving method of piezoelectric ceramics with dynamic LC matching according to claim 8, characterized in that: In step S3, adjusting the impedance of the dynamic LC matching module according to the impedance of the piezoelectric ceramic includes: Obtain the voltage, current and phase difference of piezoelectric ceramics; Calculate the required inductance and capacitance based on the voltage, current and phase difference of the piezoelectric ceramic; The motor adjusts the inductance to the required inductance, and the relay array adjusts the capacitance to the required capacitance.

10. The method for driving a piezoelectric ceramic with dynamic LC matching according to claim 9, characterized in that: The required inductance and capacitance are calculated based on the voltage, current and phase difference of the piezoelectric ceramic using the following formula: Among them, Z eq It represents the overall equivalent impedance of the dynamic LC matching module and the piezoelectric ceramic; Z L Represents the impedance of piezoelectric ceramics; R L is the real part of the impedance of the piezoelectric ceramic; X L is the imaginary part of the impedance of the piezoelectric ceramic; Z L =R L +iX L ;ω represents the angular frequency of the piezoelectric ceramic AC power supply; C P Indicates the required capacitance; L P Indicates the required inductance.

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