Dynamic matching circuit of piezoelectric ceramic transducer

Abstract

The utility model discloses a dynamic matching circuit of a piezoelectric ceramic transducer, which comprises a transformer, an inductance adjusting module, a current sampling module, a voltage sampling module, a phase discriminator and a driving signal module, and is characterized in that a primary coil of the transformer is electrically connected with a positive electrode of a power supply, an input end of the current sampling module and an input end of the voltage sampling module respectively; two ends of a secondary coil of the transformer are electrically connected with two ends of the piezoelectric ceramic transducer; the output end of the current sampling module and the output end of the voltage sampling module are electrically connected with the first input end and the second input end of the phase discriminator in a one-to-one correspondence mode, the output end of the phase discriminator is electrically connected with the input end of the driving signal module, and the output end of the driving signal module is electrically connected with the driving input end of the inductance adjusting module. The output end of the inductance adjusting module is electrically connected with the power supply cathode. According to the utility model, inductance matching is carried out according to the actual situation in the circuit, the flexibility is relatively high, and the matching precision is relatively high.

Description

Technical Field

[0001] The utility model belongs to the technical field of transducers, and in particular relates to a dynamic matching circuit of a piezoelectric ceramic transducer. Background Art

[0002] Transducers can convert one form of energy into another and are used in many products. To improve the energy conversion efficiency of transducers, impedance matching circuits are added to the transducer circuits.

[0003] Existing transducer matching methods can be divided into static matching and dynamic matching. Static matching uses the load impedance to determine the corresponding inductance and capacitance of a specific matching model. This matching solution is suitable for applications where the impedance is fixed. For applications where the load impedance changes, the most widely used method is dynamic inductance and capacitance matching. This method achieves impedance matching by adjusting the corresponding adjustable inductance and capacitance in the matching model based on real-time detection of the system's impedance matching status. Because the equivalent reactance is affected by both the matching inductance and the matching capacitance, a small change in inductance will result in a large change in reactance, resulting in low matching accuracy.

[0004] In summary, the existing matching circuit of the transducer has relatively low flexibility and low matching accuracy, resulting in relatively low energy conversion efficiency of the transducer. Utility Model Content

[0005] In view of this, the present invention provides a dynamic matching circuit for a piezoelectric ceramic transducer, the main purpose of which is to solve the problem that the existing matching circuit of the transducer has low flexibility and low matching accuracy, resulting in low energy conversion efficiency of the transducer.

[0006] To solve the above problems, the present application provides a dynamic matching circuit for a piezoelectric ceramic transducer, comprising a transformer, an inductance adjustment module, a current sampling module, a voltage sampling module, a phase detector, and a drive signal module.

[0007] Wherein, the first end of the primary coil of the transformer is electrically connected to the positive pole of the power supply, the first input end of the current sampling module, and the first input end of the voltage sampling module, respectively; the second end of the primary coil of the transformer is electrically connected to the power input end of the inductance adjustment module, the second input end of the current sampling module, and the second input end of the voltage sampling module, respectively; the two ends of the secondary coil of the transformer are electrically connected to the two ends of the piezoelectric ceramic transducer; the output end of the current sampling module and the output end of the voltage sampling module are electrically connected to the first input end and the second input end of the phase detector in a one-to-one correspondence; the output end of the phase detector is electrically connected to the input end of the drive signal module, and the output end of the drive signal module is electrically connected to the drive input end of the inductance adjustment module; the output end of the inductance adjustment module is electrically connected to the negative pole of the power supply;

[0008] The inductance adjustment module includes a first inductor, a second inductor, a freewheeling capacitor, a first IGBT tube, a second IGBT tube, a third IGBT tube and a fourth IGBT tube, wherein:

[0009] The first end of the first inductor is electrically connected to the second end of the primary coil of the transformer, the second end of the first inductor is respectively electrically connected to the first end of the second inductor, the first end of the freewheeling capacitor and the collector of the first IGBT tube, the gate of the first IGBT tube is electrically connected to the first output end of the drive signal module, the emitter of the first IGBT tube is electrically connected to the collector of the second IGBT tube, the emitter of the second IGBT tube is respectively electrically connected to the second end of the second inductor and the collector of the third IGBT tube, the emitter of the third IGBT tube is electrically connected to the collector of the fourth IGBT tube, and the emitter of the fourth IGBT tube is respectively electrically connected to the second end of the freewheeling capacitor and the negative electrode of the power supply; the gate of the second IGBT tube is electrically connected to the first output end of the drive signal module, and the gates of the third IGBT tube and the fourth IGBT tube are electrically connected to the second output end of the drive signal module.

[0010] In one embodiment of the present invention, optionally, the driving signal module includes a PI controller, a 555 timer and an inverter, wherein:

[0011] The input end of the PI controller is electrically connected to the output end of the phase detector, the output end of the PI controller is electrically connected to the control voltage input end of the 555 timer, the output end of the 555 timer is electrically connected to the gate of the first IGBT tube, the gate of the second IGBT tube and the input end of the inverter respectively, and the output end of the inverter is electrically connected to the gate of the third IGBT tube and the gate of the fourth IGBT tube.

[0012] In one embodiment of the present invention, optionally, the 555 timer outputs a pulse signal, and when the pulse signal connected to the gate of the first IGBT tube and the gate of the second IGBT tube is a positive signal, the first inductor, the freewheeling capacitor, the power supply and the transformer form a loop; when the pulse signal connected to the gate of the third IGBT tube and the gate of the fourth IGBT tube is a negative signal, the first inductor, the second inductor, the power supply and the transformer form a loop.

[0013] In one embodiment of the present utility model, optionally, the phase detector includes a first capacitor, a second capacitor, a mutual inductor, a third capacitor, a first resistor, a second resistor, a first diode, a second diode, a third inductor, a fourth capacitor, a fourth inductor, a fifth capacitor, a sixth capacitor, a fifth inductor, a seventh capacitor, an eighth capacitor, a third resistor, a fourth resistor and an adjustable resistor, wherein,

[0014] The first end of the first capacitor is electrically connected to the output end of the voltage sampling circuit, the second end of the first capacitor is electrically connected to the first end of the primary side of the mutual inductor, and the second end of the primary side of the mutual inductor is electrically connected to the negative electrode of the power supply; the first end of the secondary side of the mutual inductor is electrically connected to the first end of the third capacitor, the first end of the first resistor, and the anode of the first diode, and the second end of the secondary side of the mutual inductor is electrically connected to the second end of the third capacitor, the first end of the second resistor, and the cathode of the second diode;

[0015] A first end of the second capacitor is electrically connected to the output end of the current sampling circuit, a second end of the second capacitor is electrically connected to the second end of the second resistor, the second end of the first resistor, the first end of the third inductor, and the first end of the fourth capacitor, respectively, and a second end of the third inductor and the second end of the fourth capacitor are electrically connected to the negative electrode of the power supply;

[0016] The cathode of the first diode is electrically connected to the first end of the sixth capacitor and the first end of the fourth inductor, respectively; the second end of the fourth inductor is electrically connected to the first end of the eighth capacitor and the first end of the third resistor, the second end of the third resistor is electrically connected to the first end and the negative output end of the adjustable resistor, respectively; the second end of the sixth capacitor and the second end of the eighth capacitor are electrically connected to the negative electrode of the power supply;

[0017] The anode of the second diode is electrically connected to the first end of the fifth capacitor and the first end of the fifth inductor, respectively; the second end of the fifth inductor is electrically connected to the first end of the seventh capacitor and the first end of the fourth resistor; the second end of the fourth resistor is electrically connected to the second end of the adjustable resistor and the positive output end, respectively; and the second end of the fifth capacitor and the second end of the seventh capacitor are electrically connected to the negative electrode of the power supply.

[0018] In one embodiment of the present utility model, optionally, the voltage sampling module includes a first operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a ninth capacitor, and a tenth capacitor, wherein:

[0019] a first end of the fifth resistor being electrically connected to the first end of the primary coil of the transformer, a second end of the fifth resistor being electrically connected to the first end of the sixth resistor, the first end of the seventh resistor, the first end of the eighth resistor, and the first end of the ninth capacitor, respectively, and a second end of the eighth resistor being electrically connected to the first end of the tenth resistor and the first input terminal of the first operational amplifier, respectively;

[0020] The second end of the sixth resistor is electrically connected to the second end of the primary coil of the transformer, the second end of the seventh resistor, the second end of the ninth capacitor and the first end of the ninth resistor, respectively; the second end of the ninth resistor is electrically connected to the second input end of the first operational amplifier and the first end of the eleventh resistor, respectively; the output end of the first operational amplifier is electrically connected to the second end of the eleventh resistor and the first end of the twelfth resistor, respectively; the second end of the twelfth resistor is electrically connected to the first end of the tenth capacitor and the first input end of the phase detector, respectively; the second end of the tenth capacitor and the second end of the tenth resistor are electrically connected to the negative pole of the power supply.

[0021] In one embodiment of the present utility model, optionally, the current sampling module includes a second operational amplifier, a sampling resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor and an eleventh capacitor, wherein:

[0022] The first end of the sampling resistor is electrically connected to the first end of the primary coil of the transformer, the first end of the thirteenth resistor, and the first end of the fourteenth resistor, and the second end of the fourteenth resistor is electrically connected to the first end of the sixteenth resistor and the first input end of the second operational amplifier respectively;

[0023] The second end of the sampling resistor is electrically connected to the second end of the primary coil of the transformer, the second end of the thirteenth resistor, and the first end of the fifteenth resistor, respectively. The second end of the fifteenth resistor is electrically connected to the second input end of the second operational amplifier and the first end of the seventeenth resistor, respectively. The output end of the second operational amplifier is electrically connected to the second end of the seventeenth resistor and the first end of the eighteenth resistor, respectively. The second end of the eighteenth resistor is electrically connected to the first end of the eleventh capacitor and the second input end of the phase detector, respectively. The second end of the eleventh capacitor is electrically connected to the negative electrode of the power supply.

[0024] In one embodiment of the present invention, optionally, the number of turns of the primary coil and the number of turns of the secondary coil of the transformer meet the following requirements: Among them, R AC is the equivalent impedance of the power supply, n1 is the number of turns of the primary coil of the transformer, n2 is the number of turns of the secondary coil of the transformer, R i , is the equivalent resistance of the transducer, R x is the equivalent resistance of the transformer.

[0025] In one embodiment of the present invention, optionally, the transformer is a high-frequency transformer using an E-type ferrite core.

[0026] The utility model provides a dynamic matching circuit for a piezoelectric ceramic transducer, comprising a transformer, an inductance adjustment module, a current sampling module, a voltage sampling module, a phase detector and a drive signal module. Impedance matching is performed through the transformer, and the phase of the signal collected by the current sampling module and the signal collected by the voltage sampling module are compared by the phase detector. The output voltage signal realizes real-time adjustment of the inductance, thereby achieving real-time matching of the inductance according to the actual situation in the circuit. The circuit has relatively high flexibility and matching accuracy, thereby further improving the energy conversion efficiency of the transducer.

[0027] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0029] Figure 1 This is a structural block diagram of a dynamic matching circuit of a piezoelectric ceramic transducer according to an exemplary embodiment of the present invention;

[0030] Figure 2 A schematic diagram of an equivalent circuit structure of a piezoelectric ceramic transducer in a dynamic matching circuit of an exemplary embodiment of the present utility model;

[0031] Figure 3 This is a schematic diagram of the circuit structure of a driving signal module of a dynamic matching circuit of a piezoelectric ceramic transducer according to an exemplary embodiment of the present utility model;

[0032] Figure 4A schematic diagram of the circuit structure of a phase detector of a dynamic matching circuit of a piezoelectric ceramic transducer according to an exemplary embodiment of the present utility model;

[0033] Figure 5 This is a schematic diagram of the circuit structure of a voltage sampling circuit of a dynamic matching circuit of a piezoelectric ceramic transducer according to an exemplary embodiment of the present utility model;

[0034] Figure 6 This is a schematic diagram of the circuit structure of a current sampling circuit of a dynamic matching circuit of a piezoelectric ceramic transducer according to an exemplary embodiment of the present utility model.

[0035] in,

[0036] Figures 1-6 The numbers are as follows: 1-transformer; 2-inductance regulation module; 3-current sampling module; 4-voltage sampling module; 5-phase detector; 6-drive signal module; L1-first inductor; L2-second inductor; Cx-freewheeling capacitor; G1-first IGBT tube; G2-second IGBT tube; G3-third IGBT tube; G4-fourth IGBT tube; PI-PI controller; U1-555 timer; U2A-inverter; C1-first capacitor; C2-second capacitor; T1-mutual inductor; C3-third capacitor; R1-first resistor; R2-second resistor; D1-first diode; D2-second diode; L3-third inductor; C4-fourth capacitor; L4-fourth inductor; C5-fifth capacitor; C 6-sixth capacitor; L5-fifth inductor; C7-seventh capacitor; C8-eighth capacitor; R3-third resistor; R4-fourth resistor; Rt-adjustable resistor; U2-first operational amplifier; R5-fifth resistor; R6-sixth resistor; R7-seventh resistor; R8-eighth resistor; R9-ninth resistor; R10-tenth resistor; R11-eleventh resistor; R12-twelfth resistor; C9-ninth capacitor; C10-tenth capacitor; U2-second operational amplifier; Rc-sampling resistor; R13-thirteenth resistor; R14-fourteenth resistor; R15-fifteenth resistor; R16-sixteenth resistor; R17-seventeenth resistor; R18-eighteenth resistor; C11-eleventh capacitor; 20-transducer. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0038] To further illustrate the technical means and effects employed by the present invention to achieve its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention is provided in conjunction with the accompanying drawings and preferred embodiments. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0039] The following combination Figures 1 to 6 The dynamic matching circuit of a piezoelectric ceramic transducer according to some embodiments of the present invention is described.

[0040] In one embodiment, Figure 1 As shown, a dynamic matching circuit of a piezoelectric ceramic transducer includes a transformer 1, an inductance adjustment module 2, a current sampling module 3, a voltage sampling module 4, a phase detector 5 and a drive signal module 6.

[0041] Among them, the first end of the primary coil of the transformer 1 is electrically connected to the positive pole of the power supply, the first input end of the current sampling module 3, and the first input end of the voltage sampling module 4, respectively; the second end of the primary coil of the transformer 1 is electrically connected to the power input end of the inductance adjustment module 2, the second input end of the current sampling module 3, and the second input end of the voltage sampling module 4, respectively; the two ends of the secondary coil of the transformer 1 are electrically connected to the two ends of the piezoelectric ceramic transducer 20; the output end of the current sampling module 3 and the output end of the voltage sampling module 4 are electrically connected to the first input end and the second input end of the phase detector 5 in a one-to-one correspondence; the output end of the phase detector 5 is electrically connected to the input end of the drive signal module 6, and the output end of the drive signal module 6 is electrically connected to the drive input end of the inductance adjustment module 2; the output end of the inductance adjustment module 2 is electrically connected to the negative pole of the power supply;

[0042] The inductance adjustment module 2 includes a first inductor L1, a second inductor L2, a freewheeling capacitor Cx, a first IGBT tube G1, a second IGBT tube G2, a third IGBT tube G3 and a fourth IGBT tube G4, wherein:

[0043] The first end of the first inductor L1 is electrically connected to the second end of the primary coil of the transformer 1, the second end of the first inductor L1 is electrically connected to the first end of the second inductor L2, the first end of the freewheeling capacitor Cx and the collector of the first IGBT tube G1, the gate of the first IGBT tube G1 is electrically connected to the first output end of the drive signal module 6, the emitter of the first IGBT tube G1 is electrically connected to the collector of the second IGBT tube G2, the emitter of the second IGBT tube G2 is electrically connected to the second end of the second inductor L2 and the collector of the third IGBT tube G3, the emitter of the third IGBT tube G3 is electrically connected to the collector of the fourth IGBT tube G4, and the emitter of the fourth IGBT tube G4 is electrically connected to the freewheeling capacitor Cx.x the gate of the second IGBT tube G2 is electrically connected to the first output terminal of the drive signal module 6, and the gate of the third IGBT tube G3 and the gate of the fourth IGBT tube G4 are electrically connected to the second output terminal of the drive signal module 6.

[0044] Specifically, the equivalent circuit diagram of the piezoelectric ceramic transducer is as follows: Figure 2 As shown, it is divided into two parts, the capacitor R0 and the resistor C0 on the left are connected in parallel to form the static branch of the circuit, which is called the static capacitance. It can be easily measured by an electric meter. The parameters of this part are determined by the electrical parameters of the transducer. d , L d 、C d The series connection constitutes a dynamic branch, and the parameters of this part are determined by the mechanical vibration parameters of the transducer.

[0045] R0 and C0 can both be measured by an electric meter.

[0046] Y0 is the static branch admittance

[0047] Y d The dynamic branch admittance is

[0048] Let Y d =G d +jB d

[0049] By calculation, we can know that L d 、C d 、R d Satisfy the formula

[0050] When the transducer is at the resonant frequency, the equivalent impedance of its dynamic branch is only R d . And the resonant frequency is The impedance at this time is To maintain pure resistance, an inductor must be connected in series. The inductor size is:

[0051] The matching circuit first achieves resistance matching through transformer adjustment, and then performs reactance matching through inductance adjustment.

[0052] When transformer regulation is used to achieve resistance matching, the number of turns of the primary coil and the number of turns of the secondary coil of the transformer must meet the following requirements: Among them, R AC is the equivalent impedance of the power supply, n1 is the number of turns of the primary coil of the transformer, n2 is the number of turns of the secondary coil of the transformer, R i , is the equivalent resistance of the transducer, R xis the equivalent resistance of the transformer.

[0053] The voltage sampling module collects the voltage across the primary coil of the transformer, and the current sampling circuit collects the current flowing through the primary coil of the transformer. The phase detector performs phase comparison based on the signal output by the voltage acquisition module and the signal output by the current acquisition module, and outputs a voltage signal corresponding to the phase comparison result. After the voltage signal is adjusted by the drive signal module, the drive signal module outputs a corresponding pulse signal, which is output to the inductance adjustment module to match the corresponding tuned inductance according to the real-time voltage and real-time current of the primary coil of the transformer.

[0054] In the inductance adjustment module, the first inductor is the reference inductor, and the second inductor is the adjustment inductor. Four IGBTs form two groups of switches. The first signal from the drive signal module controls the first and second IGBTs forming Switch 1, while the second signal from the drive signal module controls the third and fourth IGBTs forming Switch 2. The switching frequency is f, and the second signal is delayed in phase by a / f from the first signal. This means that Switch 1 and Switch 2 conduct in a complementary manner. Adjusting the conduction ratio of Switch 1 to Switch 2 adjusts the equivalent voltage across the second inductor, thereby varying the equivalent current. When Switch 2 is on and Switch 1 is off, the second inductor and the first inductor are connected to the matching circuit. When Switch 1 is on and Switch 2 is off, the second inductor forms a closed loop through Switch 1. Simultaneously, the first inductor and the freewheeling capacitor are connected to the matching circuit, achieving inductance matching.

[0055] Compared with the prior art, the dynamic matching circuit of the piezoelectric ceramic transducer of the present application includes a transformer, an inductance adjustment module, a current sampling module, a voltage sampling module, a phase detector and a drive signal module. Impedance matching is performed through the transformer, and the phase of the signal collected by the current sampling module and the signal collected by the voltage sampling module are compared through the phase detector. The output voltage signal realizes real-time adjustment of the inductance, and realizes real-time matching of the inductance according to the actual situation in the circuit. It has relatively high flexibility and matching accuracy, which further improves the energy conversion efficiency of the transducer.

[0056] As a preferred implementation of this embodiment, the transformer 1 is a high-frequency transformer using an E-type ferrite core.

[0057] In one embodiment, Figure 3As shown, the drive signal module 6 includes a PI controller PI, a 555 timer U1 and an inverter U2A, wherein the input end of the PI controller PI is electrically connected to the output end of the phase detector 5, the output end of the PI controller PI is electrically connected to the control voltage input end of the 555 timer U1, the output end of the 555 timer U1 is electrically connected to the gate of the first IGBT tube G1, the gate of the second IGBT tube G2 and the input end of the inverter U2A respectively, and the output end of the inverter U2A is electrically connected to the gate of the third IGBT tube G3 and the gate of the fourth IGBT tube G4.

[0058] In this embodiment, the signal output by the phase detector is input into the PI controller. The output signal of the PI controller serves as the control voltage signal of the 555 timer, which controls the 555 timer to generate a pulse signal. The pulse signal is output to the first IGBT tube and the second IGBT tube. The pulse signal is output to the third IGBT tube and the fourth IGBT tube after passing through the inverter.

[0059] It should be noted that the method of driving the signal module to output a pulse signal can be implemented through circuits and applications in the prior art, and the technical effect achieved by this application mainly depends on the connection relationship between the modules.

[0060] In a preferred implementation of this embodiment, the 555 timer U1 outputs a pulse signal. When the pulse signal connected to the gate of the first IGBT tube G1 and the gate of the second IGBT tube G2 is a positive signal, the first inductor L1, the freewheeling capacitor Cx, the power supply and the transformer 1 form a loop; when the pulse signal connected to the gate of the third IGBT tube G3 and the gate of the fourth IGBT tube G4 is a negative signal, the first inductor L1, the second inductor L2, the power supply and the transformer 1 form a loop.

[0061] Specifically, when the 555 timer output pulse signal is positive, the first and second IGBTs are turned on, equivalent to a closed switch; the first and second IGBTs are turned off, equivalent to an open switch. Therefore, the transformer, the power supply, the first inductor in the adjustable inductor module, and the freewheeling capacitor form a loop, and only the first inductor in the adjustable inductor module is connected to the transducer's matching circuit. When the 555 timer output pulse signal is negative, the third and fourth IGBTs are turned off, equivalent to an open switch; the third and fourth IGBTs are turned on, equivalent to a closed switch. Therefore, the transformer, the power supply, the first and second inductors in the adjustable inductor module form a loop, and both the first and second inductors in the adjustable inductor module are connected to the transducer's matching circuit. Since the pulse signal output by the 555 timer is obtained based on the voltage signal and current signal of the primary coil of the transformer, the pulse signal output by the 555 timer will change the duty cycle of the switch according to the signal adjusted by the PI controller, and control the inductance value of the adjustable inductor module connected to the transducer, which is equivalent to adjusting the equivalent current of the adjustable inductor module to achieve precise matching of the transducer matching circuit.

[0062] In one embodiment, Figure 4 As shown, the phase detector 5 includes a first capacitor C1, a second capacitor C2, a mutual inductor T1, a third capacitor C3, a first resistor R1, a second resistor R2, a first diode D1, a second diode D2, a third inductor L3, a fourth capacitor C4, a fourth inductor L4, a fifth capacitor C5, a sixth capacitor C6, a fifth inductor L5, a seventh capacitor C7, an eighth capacitor C8, a third resistor R3, a fourth resistor R4 and an adjustable resistor Rt, wherein,

[0063] A first end of the first capacitor C1 is electrically connected to the output end of the voltage sampling circuit, a second end of the first capacitor C1 is electrically connected to the first end of the primary side of the mutual inductor T1, and a second end of the primary side of the mutual inductor T1 is electrically connected to the negative electrode of the power supply; a first end of the secondary side of the mutual inductor T1 is electrically connected to the first end of the third capacitor C3, the first end of the first resistor R1, and the anode of the first diode D1, and a second end of the secondary side of the mutual inductor T1 is electrically connected to the second end of the third capacitor C3, the first end of the second resistor R2, and the cathode of the second diode D2;

[0064] A first end of the second capacitor C2 is electrically connected to the output end of the current sampling circuit, a second end of the second capacitor C2 is electrically connected to the second end of the second resistor R2, the second end of the first resistor R1, the first end of the third inductor L3, and the first end of the fourth capacitor C4, respectively, and a second end of the third inductor L3 and the second end of the fourth capacitor C4 are electrically connected to the negative electrode of the power supply;

[0065] The cathode of the first diode D1 is electrically connected to the first end of the sixth capacitor C6 and the first end of the fourth inductor L4, respectively. The second end of the fourth inductor L4 is electrically connected to the first end of the eighth capacitor C8 and the first end of the third resistor R3. The second end of the third resistor R3 is electrically connected to the first end and the negative output end of the adjustable resistor Rt, respectively. The second end of the sixth capacitor C6 and the second end of the eighth capacitor C8 are electrically connected to the negative electrode of the power supply.

[0066] The anode of the second diode D2 is electrically connected to the first end of the fifth capacitor C5 and the first end of the fifth inductor L5, respectively. The second end of the fifth inductor L5 is electrically connected to the first end of the seventh capacitor C7 and the first end of the fourth resistor R4. The second end of the fourth resistor R4 is electrically connected to the second end of the adjustable resistor Rt and the positive output end, respectively. The second end of the fifth capacitor C5 and the second end of the seventh capacitor C7 are electrically connected to the negative electrode of the power supply.

[0067] Specifically, the first capacitor and the second capacitor form a capacitor voltage divider circuit, providing one high-frequency signal for the phase detector; the first capacitor and the mutual inductor T1 provide another high-frequency signal for the phase detector. The function of the first capacitor is to shift the phase by 90° and provide a relatively uniform high-frequency current for the mutual inductor T1. The fifth capacitor, the sixth capacitor, the seventh capacitor, the eighth capacitor and the fourth inductor and the fifth inductor form a π-type filter network for filtering out high-frequency signals. The third resistor and the fourth resistor are DC output resistors, which play an isolation role. The adjustable resistor is a potentiometer, which is used to adjust the output balance. When the phase difference between the voltage and current sampling signals is zero, the output voltage of the phase detector can be made to zero volts by adjusting the potentiometer. This feature enables the phase detector to accurately output the corresponding voltage signal according to the phase difference between the output signal of the current acquisition module and the output signal of the voltage acquisition module.

[0068] In one embodiment, Figure 5 As shown, the voltage sampling module 4 includes a first operational amplifier U1, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a ninth capacitor C9 and a tenth capacitor C10, wherein:

[0069] a first end of a fifth resistor R5 electrically connected to a first end of the primary coil of the transformer 1; a second end of the fifth resistor R5 electrically connected to a first end of a sixth resistor R6, a first end of a seventh resistor R7, a first end of an eighth resistor R8, and a first end of a ninth capacitor C9; a second end of the eighth resistor R8 electrically connected to a first end of a tenth resistor R10 and a first input end of the first operational amplifier U1;

[0070] The second end of the sixth resistor R6 is electrically connected to the second end of the primary coil of the transformer 1, the second end of the seventh resistor R7, the second end of the ninth capacitor C9, and the first end of the ninth resistor R9, respectively. The second end of the ninth resistor R9 is electrically connected to the second input end of the first operational amplifier U1 and the first end of the eleventh resistor R11, respectively. The output end of the first operational amplifier U1 is electrically connected to the second end of the eleventh resistor R11 and the first end of the twelfth resistor R12, respectively. The second end of the twelfth resistor R12 is electrically connected to the first end of the tenth capacitor C10 and the first input end of the phase detector 5, respectively. The second end of the tenth capacitor C10 and the second end of the tenth resistor R10 are electrically connected to the negative pole of the power supply.

[0071] In this embodiment, the voltage is divided by the fifth resistor, the sixth resistor, and the seventh resistor, passes through the differential follower amplifier circuit, and then is filtered by the RC low-pass filter and input to the first input terminal of the phase detector.

[0072] In one embodiment, Figure 6 As shown, the current sampling module 3 includes a second operational amplifier U2, a sampling resistor Rc, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18 and an eleventh capacitor C11, wherein:

[0073] A first end of the sampling resistor Rc is electrically connected to the first end of the primary coil of the transformer 1, the first end of the thirteenth resistor R13, and the first end of the fourteenth resistor R14. A second end of the fourteenth resistor R14 is electrically connected to the first end of the sixteenth resistor R16 and the first input end of the second operational amplifier U2.

[0074] The second end of the sampling resistor Rc is electrically connected to the second end of the primary coil of the transformer 1, the second end of the thirteenth resistor R13, and the first end of the fifteenth resistor R15, respectively. The second end of the fifteenth resistor R15 is electrically connected to the second input end of the second operational amplifier U2 and the first end of the seventeenth resistor R17, respectively. The output end of the second operational amplifier U2 is electrically connected to the second end of the seventeenth resistor R17 and the first end of the eighteenth resistor R18, respectively. The second end of the eighteenth resistor R18 is electrically connected to the first end of the eleventh capacitor C11 and the second input end of the phase detector 5, respectively. The second end of the eleventh capacitor C11 is electrically connected to the negative electrode of the power supply.

[0075] In this embodiment, when current flows through the sampling resistor, the voltage across the sampling resistor is collected to convert the current into a corresponding small voltage. The voltage across the sampling resistor is then differentially amplified, filtered, and input to the second input terminal of the phase detector.

[0076] It should be understood that various modifications may be made to the embodiments of the present application. Therefore, the above description should not be considered as limiting, but merely as an example of an embodiment. Other modifications within the scope and spirit of the present application will occur to those skilled in the art.

[0077] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0078] These and other characteristics of the present application will become apparent from the following description of a preferred form of embodiment given as a non-limiting example with reference to the accompanying drawings.

[0079] It should also be understood that although the present application has been described with reference to certain specific examples, those skilled in the art will readily be able to implement many other equivalent forms of the present application.

[0080] The above and other aspects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0081] Specific embodiments of the present application will be described hereinafter with reference to the accompanying drawings; however, it should be understood that the embodiments described are merely examples of the present application and may be implemented in a variety of ways. Familiar and / or repetitive functions and structures are not described in detail to avoid obscuring the present application with unnecessary or redundant details. Therefore, the specific structural and functional details described herein are not intended to be limiting, but rather serve merely as a basis and representative basis for the claims to teach those skilled in the art to variously utilize the present application with substantially any suitable detailed structure.

[0082] This specification may use the phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," which may all refer to one or more of the same or different embodiments according to the present application.

[0083] The above embodiments are merely exemplary embodiments of the present application and are not intended to limit the scope of the present application. The scope of protection of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and scope of protection of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the scope of protection of the present application.

Claims

1. A dynamic matching circuit for a piezoelectric ceramic transducer, characterized in that: Including transformer, inductance adjustment module, current sampling module, voltage sampling module, phase detector and drive signal module, Wherein, the first end of the primary coil of the transformer is electrically connected to the positive pole of the power supply, the first input end of the current sampling module, and the first input end of the voltage sampling module, respectively; the second end of the primary coil of the transformer is electrically connected to the power input end of the inductance adjustment module, the second input end of the current sampling module, and the second input end of the voltage sampling module, respectively; the two ends of the secondary coil of the transformer are electrically connected to the two ends of the piezoelectric ceramic transducer; the output end of the current sampling module and the output end of the voltage sampling module are electrically connected to the first input end and the second input end of the phase detector in a one-to-one correspondence; the output end of the phase detector is electrically connected to the input end of the drive signal module, and the output end of the drive signal module is electrically connected to the drive input end of the inductance adjustment module; the output end of the inductance adjustment module is electrically connected to the negative pole of the power supply; The inductance adjustment module includes a first inductor, a second inductor, a freewheeling capacitor, a first IGBT tube, a second IGBT tube, a third IGBT tube and a fourth IGBT tube, wherein: The first end of the first inductor is electrically connected to the second end of the primary coil of the transformer, the second end of the first inductor is respectively electrically connected to the first end of the second inductor, the first end of the freewheeling capacitor and the collector of the first IGBT tube, the gate of the first IGBT tube is electrically connected to the first output end of the drive signal module, the emitter of the first IGBT tube is electrically connected to the collector of the second IGBT tube, the emitter of the second IGBT tube is respectively electrically connected to the second end of the second inductor and the collector of the third IGBT tube, the emitter of the third IGBT tube is electrically connected to the collector of the fourth IGBT tube, and the emitter of the fourth IGBT tube is respectively electrically connected to the second end of the freewheeling capacitor and the negative electrode of the power supply; the gate of the second IGBT tube is electrically connected to the first output end of the drive signal module, and the gates of the third IGBT tube and the fourth IGBT tube are electrically connected to the second output end of the drive signal module.

2. The dynamic matching circuit of the piezoelectric ceramic transducer according to claim 1, characterized in that: The driving signal module includes a PI controller, a 555 timer and an inverter, wherein: The input end of the PI controller is electrically connected to the output end of the phase detector, the output end of the PI controller is electrically connected to the control voltage input end of the 555 timer, the output end of the 555 timer is electrically connected to the gate of the first IGBT tube, the gate of the second IGBT tube and the input end of the inverter respectively, and the output end of the inverter is electrically connected to the gate of the third IGBT tube and the gate of the fourth IGBT tube.

3. The dynamic matching circuit of the piezoelectric ceramic transducer according to claim 2, characterized in that: The 555 timer outputs a pulse signal. When the pulse signal connected to the gate of the first IGBT tube and the gate of the second IGBT tube is a positive signal, the first inductor, the freewheeling capacitor, the power supply and the transformer form a loop; when the pulse signal connected to the gate of the third IGBT tube and the gate of the fourth IGBT tube is a negative signal, the first inductor, the second inductor, the power supply and the transformer form a loop.

4. The dynamic matching circuit of the piezoelectric ceramic transducer according to claim 1, characterized in that: The phase detector includes a first capacitor, a second capacitor, a mutual inductor, a third capacitor, a first resistor, a second resistor, a first diode, a second diode, a third inductor, a fourth capacitor, a fourth inductor, a fifth capacitor, a sixth capacitor, a fifth inductor, a seventh capacitor, an eighth capacitor, a third resistor, a fourth resistor and an adjustable resistor, wherein: The first end of the first capacitor is electrically connected to the output end of the voltage sampling module, the second end of the first capacitor is electrically connected to the first end of the primary side of the mutual inductor, and the second end of the primary side of the mutual inductor is electrically connected to the negative electrode of the power supply; the first end of the secondary side of the mutual inductor is electrically connected to the first end of the third capacitor, the first end of the first resistor, and the anode of the first diode, and the second end of the secondary side of the mutual inductor is electrically connected to the second end of the third capacitor, the first end of the second resistor, and the cathode of the second diode; A first end of the second capacitor is electrically connected to the output end of the current sampling module, a second end of the second capacitor is electrically connected to the second end of the second resistor, the second end of the first resistor, the first end of the third inductor, and the first end of the fourth capacitor, respectively, and a second end of the third inductor and the second end of the fourth capacitor are electrically connected to the negative electrode of the power supply; The cathode of the first diode is electrically connected to the first end of the sixth capacitor and the first end of the fourth inductor, respectively; the second end of the fourth inductor is electrically connected to the first end of the eighth capacitor and the first end of the third resistor, the second end of the third resistor is electrically connected to the first end and the negative output end of the adjustable resistor, respectively; the second end of the sixth capacitor and the second end of the eighth capacitor are electrically connected to the negative electrode of the power supply; The anode of the second diode is electrically connected to the first end of the fifth capacitor and the first end of the fifth inductor, respectively; the second end of the fifth inductor is electrically connected to the first end of the seventh capacitor and the first end of the fourth resistor; the second end of the fourth resistor is electrically connected to the second end of the adjustable resistor and the positive output end, respectively; and the second end of the fifth capacitor and the second end of the seventh capacitor are electrically connected to the negative electrode of the power supply.

5. The dynamic matching circuit of the piezoelectric ceramic transducer according to claim 1, characterized in that: The voltage sampling module includes a first operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a ninth capacitor, and a tenth capacitor, wherein: a first end of the fifth resistor being electrically connected to the first end of the primary coil of the transformer, a second end of the fifth resistor being electrically connected to the first end of the sixth resistor, the first end of the seventh resistor, the first end of the eighth resistor, and the first end of the ninth capacitor, respectively, and a second end of the eighth resistor being electrically connected to the first end of the tenth resistor and the first input terminal of the first operational amplifier, respectively; The second end of the sixth resistor is electrically connected to the second end of the primary coil of the transformer, the second end of the seventh resistor, the second end of the ninth capacitor and the first end of the ninth resistor, respectively; the second end of the ninth resistor is electrically connected to the second input end of the first operational amplifier and the first end of the eleventh resistor, respectively; the output end of the first operational amplifier is electrically connected to the second end of the eleventh resistor and the first end of the twelfth resistor, respectively; the second end of the twelfth resistor is electrically connected to the first end of the tenth capacitor and the first input end of the phase detector, respectively; the second end of the tenth capacitor and the second end of the tenth resistor are electrically connected to the negative pole of the power supply.

6. The dynamic matching circuit of the piezoelectric ceramic transducer according to claim 1, characterized in that: The current sampling module includes a second operational amplifier, a sampling resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor and an eleventh capacitor, wherein: The first end of the sampling resistor is electrically connected to the first end of the primary coil of the transformer, the first end of the thirteenth resistor, and the first end of the fourteenth resistor, and the second end of the fourteenth resistor is electrically connected to the first end of the sixteenth resistor and the first input end of the second operational amplifier respectively; The second end of the sampling resistor is electrically connected to the second end of the primary coil of the transformer, the second end of the thirteenth resistor, and the first end of the fifteenth resistor, respectively. The second end of the fifteenth resistor is electrically connected to the second input end of the second operational amplifier and the first end of the seventeenth resistor, respectively. The output end of the second operational amplifier is electrically connected to the second end of the seventeenth resistor and the first end of the eighteenth resistor, respectively. The second end of the eighteenth resistor is electrically connected to the first end of the eleventh capacitor and the second input end of the phase detector, respectively. The second end of the eleventh capacitor is electrically connected to the negative electrode of the power supply.

7. The dynamic matching circuit of the piezoelectric ceramic transducer according to any one of claims 1 to 6, characterized in that: The number of turns of the primary coil and the number of turns of the secondary coil of the transformer meet the following requirements: Among them, R AC is the equivalent impedance of the power supply, n1 is the number of turns of the primary coil of the transformer, n2 is the number of turns of the secondary coil of the transformer, R i , is the equivalent resistance of the transducer, R x is the equivalent resistance of the transformer.

8. The dynamic matching circuit of the piezoelectric ceramic transducer according to any one of claims 1 to 6, characterized in that: The transformer is a high-frequency transformer using an E-type ferrite core.

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