Radial vibration piezoelectric transformer with asymmetric protruding electrodes and preparation method of radial vibration piezoelectric transformer

Abstract

The invention relates to the technical field of piezoelectric transformers, in particular to a radial vibration piezoelectric transformer with asymmetric protruding electrodes and a preparation method of the radial vibration piezoelectric transformer. A primary side and a secondary side of the piezoelectric transformer can be formed by alternately stacking piezoelectric ceramic materials with the same or two different dielectric constants, and no isolation piece or an isolation piece is arranged between the primary side and the secondary side; the intelligent temperature control layer is arranged on the outer layer of the transformer and comprises a thermosensitive phase change material; the self-adaptive frequency regulation circuit is connected with the input end of the transformer; and the insulation heat dissipation channel structure forms an annular insulation heat dissipation gap at the edge of the ceramic single sheet. Through reasonable matching of primary and secondary structure parameters and a load relation, the piezoelectric transformer has excellent characteristics of constant current output, constant power output, same phase or pi phase difference between input voltage and input current and the like, the efficiency of the piezoelectric transformer is improved to the greatest extent, the loss of the piezoelectric transformer is reduced, and the reliability of the piezoelectric transformer is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of piezoelectric transformer, in particular to a radial vibration piezoelectric transformer with asymmetric protruding electrodes and a preparation method thereof. BACKGROUND

[0002] The radial vibration piezoelectric transformer is a new type of piezoelectric transformer in development. The piezoelectric transformer has the outstanding advantages of realizing low-voltage and high-power output with small size, and can be used in electronic rectifiers, adapters and power supplies. Taking a circular radial vibration mode transformer as an example, the previous radial vibration piezoelectric transformer has paid attention to the single-piece shape of the transformer, the multi-piece stacking mode, the electrode lead-out, the composition of the insulating assembly and other issues, so as to achieve the purpose of output voltage reduction or voltage increase, and to achieve certain technical performance indicators, and to meet the specific safety standards of insulation isolation between primary and secondary. The traditional radial vibration piezoelectric transformer has the following technical bottlenecks:

[0003] The circular radial vibration mode single-piece surface electrode and the side electrode formed by extending the same are symmetrical. When the circular piece vibrates radially, two symmetrical standing wave points are often formed at two symmetrical protruding parts (i.e. the side electrode welding lead-out line part) outside the circumference of the single piece, which is larger than the diameter of the single piece. A large amount of energy is gathered at the standing wave points, forming two symmetrical heat points, and the high temperature may even melt the brazing points at the side electrode.

[0004] The efficiency fluctuates greatly when the load changes, and lacks self-adaptive adjustment capability;

[0005] The heat dissipation performance is insufficient, affecting the long-term reliability;

[0006] Although the prior art has made certain improvements through electrode structure optimization, it has not fundamentally solved the above problems. SUMMARY

[0007] The purpose of the present application is to provide a radial vibration piezoelectric transformer with asymmetric protruding electrodes and a preparation method thereof, to solve the problems raised in the background art.

[0008] To achieve the above purpose, the present application provides the following technical solution: a radial vibration piezoelectric transformer with asymmetric protruding electrodes, comprising:

[0009] a basic piezoelectric transformer unit composed of circular or regular polygon ceramic single pieces stacked in parallel or series;

[0010] a multi-layer composite ceramic structure composed of layers of piezoelectric ceramic materials with the same or different dielectric constants;

[0011] an intelligent temperature control layer arranged on the outer layer of the transformer and composed of a thermosensitive phase change material;

[0012] An adaptive frequency adjustment circuit is connected to the transformer input end;

[0013] A heat dissipation channel structure forms an annular heat dissipation gap at the edge of the ceramic monolithic body.

[0014] Preferably, the difference between the dielectric constants of the piezoelectric ceramic materials with different dielectric constants in the multi-layer composite ceramic structure is 20%-50%.

[0015] Preferably, the intelligent temperature control layer contains microcapsule-encapsulated thermosensitive phase change materials with a phase change temperature of 40-80℃ and a phase change latent heat of ≥150J / g.

[0016] Preferably, the adaptive frequency adjustment circuit comprises:

[0017] A frequency detection module for real-time monitoring of the operating frequency;

[0018] A comparator circuit for comparing the detected frequency with the optimal efficiency frequency;

[0019] A feedback adjustment module for automatically adjusting the driving frequency according to the comparison result.

[0020] Preferably, the annular heat dissipation gap of the heat dissipation channel structure has a width of 0.5-1.0mm.

[0021] Preferably, it further comprises a load detection module, which comprises:

[0022] A current sensor for detecting changes in output current;

[0023] A voltage detection circuit for monitoring output voltage fluctuations;

[0024] A microprocessor for automatically adjusting operating parameters based on detection data.

[0025] Preferably, the response time of the load detection module is ≤10ms and the detection accuracy is ≥95%.

[0026] Preferably, the width of the protruding part of the surface electrode of the ceramic monolithic body accounts for 20%-35% of the diameter, and the recessed part accounts for 25%-40%.

[0027] Preferably, the transformer further comprises a protective coating comprising a nanosilica composite material, and the coating has a thickness of 5-20μm.

[0028] A method for preparing a radial vibration piezoelectric transformer with asymmetric protruding electrodes, comprising the following steps:

[0029] A multi-layer composite ceramic body is prepared, and ceramic sheets with different dielectric constants are prepared by dry pressing, film rolling or flow casting process;

[0030] Electrode printing uses screen printing technology to form asymmetrical electrode patterns on the ceramic surface;

[0031] The assembly and integration process combines the intelligent temperature control layer, heat dissipation structure, and ceramic body.

[0032] Circuit connection, installation of adaptive frequency adjustment circuit and load detection module;

[0033] Protective treatment involves applying a nano-protective coating.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1) The non-central symmetry of the primary and secondary surface electrodes and side electrodes avoids the generation of standing wave points, eliminates the heating phenomenon caused by standing wave points, and reduces losses.

[0036] 2) When the primary drive circuit adopts an intermittent half-sine wave drive, it will not cause depolarization of the primary single chip.

[0037] 3) The primary and secondary grounds are located on opposite sides of the same isolation plate as much as possible, which reduces leakage losses caused by the pressure difference between the primary and secondary grounds;

[0038] 4) It minimizes insulation coverage, thereby reducing insulation loss;

[0039] 5) The selection of the optimal efficiency coefficient and the determination of the operating frequency minimize the transformer's internal resistance (including mechanical loss internal resistance, piezoelectric loss internal resistance and dielectric loss internal resistance), thereby maximizing the equivalent rated load and minimizing the transformer's losses.

[0040] 6) Improved transformer performance, making it more suitable for ballast applications when the transformer has constant output power characteristics;

[0041] 7) Within a certain load range, the transformer exhibits constant current characteristics, and therefore can be used as a constant current source with special requirements. Attached Figure Description

[0042] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a diagram showing the shape of the inner circle B-side surface electrode of the present invention;

[0044] Figure 2 This is a top view of a Class AB ceramic monolith in the F direction, with the inner circle showing the shape of the surface electrode on the A side.

[0045] Figure 3 This is a front view of a single ceramic piece of type B'A.

[0046] Figure 4 This is a front view of a single ceramic piece of type AB.

[0047] Figure 5 This is a structural diagram of a radial vibration piezoelectric transformer. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Please see Figures 1 to 4 The present invention provides a technical solution:

[0050] A radial vibration piezoelectric transformer with asymmetric protruding electrodes, comprising:

[0051] The basic piezoelectric transformer unit is composed of circular or regular polygonal ceramic wafers stacked in parallel or series.

[0052] Multilayer composite ceramic structure, comprising alternating layers of piezoelectric ceramic materials of the same or two different dielectric constants;

[0053] The intelligent temperature control layer, located on the outer layer of the transformer, contains a thermosensitive phase change material;

[0054] An adaptive frequency adjustment circuit is connected to the input terminal of the transformer.

[0055] The heat dissipation channel structure forms an annular heat dissipation gap at the edge of the ceramic wafer.

[0056] Specifically, in the multilayer composite ceramic structure, the difference in dielectric constant of piezoelectric ceramic materials with different dielectric constants is 20%-50%.

[0057] Specifically, the intelligent temperature control layer contains a microcapsule-encapsulated thermosensitive phase change material with a phase change temperature of 40℃-80℃ and a latent heat of phase change ≥150J / g.

[0058] Specifically, the adaptive frequency adjustment circuit includes:

[0059] The frequency detection module monitors the operating frequency in real time.

[0060] The comparator circuit compares the detection frequency with the optimal efficiency frequency;

[0061] a feedback adjustment module automatically adjusts the driving frequency according to the comparison result.

[0062] Specifically, the annular heat dissipation gap width of the heat dissipation channel structure is 0.5mm-1.0mm.

[0063] Specifically, the load detection module further comprises:

[0064] a current sensor detects output current changes;

[0065] a voltage detection circuit monitors output voltage fluctuations;

[0066] a microprocessor automatically adjusts working parameters according to detection data.

[0067] Specifically, the response time of the load detection module is ≤10ms, and the detection accuracy is ≥95%.

[0068] Specifically, the protruding part of the ceramic monolithic surface electrode accounts for 20%-35% of the diameter, and the recessed part accounts for 25%-40%.

[0069] Specifically, the transformer further comprises a protective coating comprising a nano-silicon dioxide composite material, and the coating thickness is 5μm-20μm.

[0070] A preparation method of a radial vibration piezoelectric transformer with an asymmetric protruding electrode comprises the following steps:

[0071] Preparation of a multilayer composite ceramic body, using dry pressing or film rolling or flow forming process to form ceramic sheets with different dielectric constants;

[0072] Electrode printing, using screen printing technology to form an asymmetric electrode pattern on the ceramic surface;

[0073] Assembly integration, integrating the intelligent temperature control layer, heat dissipation structure and ceramic main body;

[0074] Circuit connection, installing adaptive frequency adjustment circuit and load detection module;

[0075] Protection treatment, applying a nano protective coating.

[0076] The present application proposes three major innovative technical solutions:

[0077] Solution one: multilayer composite ceramic structure design

[0078] Different piezoelectric ceramic materials with different dielectric constants are alternately stacked, and through structural design calculation, according to the complementary effect of different material properties of the primary and secondary of the transformer, the working frequency range is widened, and the transformer efficiency is improved.

[0079] Scheme two: Intelligent temperature control and heat dissipation system integrates heat-sensitive phase change material layer and annular heat dissipation channel to realize active temperature control and efficient heat dissipation

[0080] Scheme three: The adaptive adjustment circuit realizes automatic optimization of working parameters through frequency detection and load monitoring.

[0081] Example 1: Preparation of a multilayer composite structure

[0082] Two piezoelectric ceramic layers with different dielectric constants (ε1=1200, ε2=1800) were prepared by dry pressing process, and the layer thickness ratio was 1.2:0.5. The whole structure was formed by resin bonding.

[0083] Example 2: Test of intelligent temperature control system

[0084] Under the condition of 85 DEG C high temperature environment, the temperature rise is controlled within 15 DEG C, and the efficiency attenuation is less than 3% after 100 hours of continuous work.

[0085] Example 3: Verification of adaptive adjustment performance

[0086] Under the condition that the load suddenly changes from 50% to 150%, the system completes adjustment within 15ms, and the output stability is greater than 98%.

[0087] Technical effects:

[0088] The working temperature range is expanded to -25 DEG C to +125 DEG C.

[0089] The efficiency is improved by more than 8%, and the constant power fluctuation is less than 2%;

[0090] The load adaptability is improved by 50%;

[0091] The service life is prolonged by more than 3 times.

[0092] The primary and secondary of the transformer are respectively stacked in parallel or series by ceramic single pieces, the ceramic single pieces are circular or regular polygons, and the surface electrodes on the upper and lower surfaces of the ceramic single pieces are circular or regular polygons with the same geometric center as the upper and lower surfaces, and the radius or side length is less than the radius or side length of the upper and lower surfaces, and the surface electrodes are formed by silver, the circular or regular polygon of the surface electrode has radial convex and concave parts, and the upper and lower surface electrodes are not center-symmetric, from the convex part of the upper and lower surface electrodes to the edge of the ceramic single piece, the silvering is carried out along the side surface of the ceramic single piece, and two side electrodes are formed on the other surface edge, and the two side electrodes are not center-symmetric.

[0093] The piezoelectric transformer prepared by the application has the following beneficial effects:

[0094] 1) The non-central symmetry of the primary and secondary surface electrodes and the side electrode avoids the generation of standing wave points, eliminates the heat phenomenon caused by the standing wave points, and reduces the loss;

[0095] 2) When the primary driving circuit adopts the intermittent half-sine wave driving form, the depolarization phenomenon will not occur to the primary single piece;

[0096] 3) The primary and secondary ground are as far as possible on both sides of the same isolation sheet, reducing the leakage current loss caused by the primary and secondary pressure difference;

[0097] 4) The insulation covering is as far as possible reduced, thereby reducing the insulation loss;

[0098] 5) The selection of the optimal efficiency coefficient and the determination of the working frequency make the internal resistance of the transformer (including the mechanical loss resistance, the piezoelectric loss resistance and the dielectric loss resistance) minimum, the equivalent rated load maximum, and thus the loss of the transformer minimum;

[0099] 6) The determination method of the ratio of the total thickness of the primary and secondary makes the input voltage and the input current of the transformer in the same phase or the phase difference π;

[0100] 7) The performance of the transformer is improved, and when the transformer has the constant output power characteristic, it is more suitable for ballasts;

[0101] 8) Within a certain load range, the transformer shows the constant current characteristic, and thus can be used for special constant current sources.

[0102] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A radial vibration piezoelectric transformer with asymmetric protruding electrodes, characterized by, The piezoelectric transformer unit comprises a plurality of ceramic monolithic pieces stacked in parallel or series, wherein each ceramic monolithic piece is circular or regular polygonal, and the surface electrodes on the upper and lower surfaces of each ceramic monolithic piece are circular or regular polygonal silver films with the same geometric center as the upper and lower surfaces, and the radius or side length of the circular or regular polygonal silver films is smaller than that of the upper and lower surfaces, and the circular or regular polygonal silver films have radial convex and concave parts, and the surface electrodes are not center-symmetric. The upper and lower surface electrodes are silvered from the convex parts to the edges of the ceramic monolithic piece along the side surfaces of the ceramic monolithic piece to form two side electrodes on the other surface edges, and the two side electrodes are not center-symmetric. The piezoelectric transformer unit further comprises a multi-layer composite ceramic structure, a smart temperature control layer, an adaptive frequency adjustment circuit, and a heat dissipation channel structure. The multi-layer composite ceramic structure comprises piezoelectric ceramic materials with different dielectric constants which are alternately stacked. The smart temperature control layer is arranged on the outer layer of the piezoelectric transformer unit and comprises a thermosensitive phase change material. The adaptive frequency adjustment circuit is connected to the input end of the piezoelectric transformer unit. The heat dissipation channel structure is formed on the edges of the ceramic monolithic piece to form annular heat dissipation gaps. The difference between the dielectric constants of the piezoelectric ceramic materials with different dielectric constants in the multi-layer composite ceramic structure is 20%-50%.

2. A radial vibration piezoelectric transformer with asymmetric protruding electrodes according to claim 1, characterized in that, The piezoelectric transformer unit further comprises a load detection module.

3. The radial vibration piezoelectric transformer as claimed in claim 1, characterized by The load detection module comprises a current sensor, a voltage detection circuit, and a microprocessor.

4. The radial vibration piezoelectric transformer with asymmetric protruding electrodes according to claim 1, characterized in that, The response time of the load detection module is less than or equal to 10 ms, and the detection accuracy is greater than or equal to 95%.

5. The radial vibration piezoelectric transformer with asymmetric protruding electrodes according to claim 1, characterized in that, The width of the convex part of the surface electrode of the ceramic monolithic piece accounts for 20%-35% of the diameter, and the concave part accounts for 25%-40%. The piezoelectric transformer unit further comprises a protective insulating coating with a thickness of 5 μm-20 μm. The ratio of the number of layers of the primary and secondary stages is inversely proportional to the ratio of the input and output voltages. The piezoelectric transformer unit has an output constant power characteristic when the load changes within the range of R±△R around the rated load R, or a constant current output characteristic when the load is far less than the rated load R.

6. The radial vibration piezoelectric transformer with asymmetric protruding electrodes according to claim 1, characterized in that, The piezoelectric transformer unit is manufactured by using a dry pressing, film rolling or flow casting process.

7. The piezoelectric transformer of claim 1, wherein the asymmetric protrusion electrode is formed on the outer surface of the piezoelectric body. ​ ​ ​ ​ 8. A radial vibration piezoelectric transformer with asymmetric protruding electrodes according to claim 6, characterized in that, ​ 9. The piezoelectric transformer of claim 1, wherein the asymmetric protrusion electrode is formed on the outer surface of the piezoelectric body. ​ 10. The piezoelectric transformer of claim 1, wherein the asymmetric protruding electrode is formed on the outer surface of the piezoelectric body. ​ 11. The piezoelectric transformer of claim 1, wherein the asymmetric protruding electrode is formed on the outer surface of the piezoelectric body. ​ 12. A method of manufacturing a radial vibration piezoelectric transformer with asymmetric protruding electrodes, characterized by, ​ ​ Electrode printing, using screen printing technology to form an asymmetric electrode pattern on the surface of the ceramic sheet, having the same geometric center on the upper and lower surfaces, a circular or regular polygonal surface electrode formed by silver on the upper and lower surfaces with a radius or side length smaller than that of the upper and lower surfaces, the circular or regular polygonal surface electrode having radial convex and concave parts, and the upper and lower surface electrodes being non-centrally symmetric; From the convex part of the upper and lower surface electrodes to the edge of the ceramic single sheet, silvering along the side of the ceramic single sheet, silvering to the other surface edge to form two side electrodes, the two side electrodes being non-centrally symmetric; By designing the ratio of the number of primary and secondary layers of the transformer, the optimal efficiency coefficient, the secondary structure characteristic coefficient, the ratio of the number of secondary layers, the total thickness ratio of the primary and secondary, and the equivalent wave number, the relationship between the primary and secondary structure parameters is determined, the primary and secondary structure parameter values are obtained, and the parallel, series and stacking modes of the primary and secondary are determined; Assembly integration, according to the calculated parameter structure, the ceramic sheet is integrated, the intelligent temperature control layer, the heat dissipation structure and the composite ceramic main body are connected together, and the protection treatment is applied, and the nano protection coating is applied; Circuit connection, installing adaptive frequency adjustment circuit and load detection module.

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