WO1996015560A1

WO1996015560A1 - Composite piezoelectric ceramic transformer and manufacture method thereof

Info

Publication number: WO1996015560A1
Application number: PCT/CN1995/000089
Authority: WO
Inventors: Weiti Deng; Hongyi Li
Original assignee: Beijing Wide Tech. Electron & Electric Equipment Co. Ltd.
Priority date: 1994-11-10
Filing date: 1995-11-07
Publication date: 1996-05-23
Also published as: AU3838895A

Abstract

A composite piezoelectric ceramic transformer comprises at least two driven portions, the generating portions whose number is one less than that of the driven portion and the insulation sheets whose number is twice as many as generating portion. These portions are laminated in an order of driven portion, insulation sheet, generating portion, insulation sheet, driven portion and so on. There are insulation films on the outer surfaces of first and last driven portions respectively. The piezoelectric ceramic transformer has a non-single-sintered chip structure which may be monolithic-composite or multilayer-bonding. The interstage insulation of the transformer can be improved and a step-down conversion from power supply to low voltage can be realized.

Description

Composite structure piezoelectric ceramic transformer and manufacturing method thereof

The present invention generally relates to a piezoelectric ceramic transformer with a composite structure and a manufacturing method thereof, and more particularly, to a piezoelectric monolithic piezoelectric transformer with a composite monolithic structure and a multilayer piezoelectric ceramic prepared by a bonding method. Transformers and manufacturing methods thereof also involve special materials for producing such piezoelectric ceramic transformers.

Background technique

Common transformers and pulse transformers both transmit signals and achieve "transformation" through magnetic coupling. Ordinary transformers use silicon steel sheets as magnetic cores, while pulse transformers use high-permeability oxygen-based or beryllium-molybdenum magnetic cores. With the development of electronic technology. Electronic components have been developed to be light, thin, short, and small. Various integrated circuits, resistors, capacitors and other components have been miniaturized. Only transformers, especially power transformers, still cannot get rid of volume. Large and heavy cores and coils. In fact, the size of the power supply has seriously affected the continued development of many electronic products. For example, the power supply of notebook computers has become a major obstacle to its portability.

The use of piezoelectric ceramic transformers is likely to promote the process of power chip sizing from a completely new perspective. Because:

(1) Piezoelectric ceramic transformers generally work near their mechanical resonance frequency and are not restricted by the cut-off frequency of magnetic materials. The operating frequency can be greatly increased.

(2) The existing performance of piezoelectric materials and the accumulated experience in manufacturing piezoelectric transducers make it possible to produce piezoelectric ceramic transformers with high output power density and conversion efficiency.

(3) Since piezoelectric ceramic transformers can borrow other mature electronic ceramic production tools Reconstruction of art and production equipment can more conveniently organize industrialized large-scale production. However, in a large amount of research, most manufacturers are pursuing high-transformation-ratio piezoelectric ceramic transformers, which are used in high-voltage generators, and pursue small size and high boost ratio. Due to its structural reasons, it cannot be used to convert AC 220 / l 10v 50 / 60Hz to DC several volts to several tens volts.

It was not until 1992 that piezoelectric ceramic transformers for AC-DC conversion began to appear, such as Japanese Patent Application Laid-Open No. 4-20206580 by Akio Iwamoto, etc., and Japanese Patent Application Laid-Open No. 4-206581 by Uishihara, etc. Japanese Patent Application Laid-open Nos. 4-206582, JP 5-235432, JP 5-235433, JP 5-235434, and Zaitsu, T in the IEICE Electronic Society Records February 1994 Volume E77-C No. 2 P280-6 Only the piezoelectric ceramic transformer disclosed in "2MHz Power Converter Using Piezo Transformer" has higher conversion efficiency and higher output power density. However, these ceramic transformers still have many disadvantages. First of all, due to the integrated sintering, the high-voltage and low-voltage ends can only use the same piezoelectric ceramic material as the insulating layer between the two ends, and this material has a large dielectric constant. The capacitance value can reach the order of nF. Therefore, the insulating layer has a bypass effect on high-frequency high driving voltage without good insulation. Secondly, because the operating frequency is too high, it is difficult to configure a good driving circuit, which results in the disadvantage of low conversion efficiency of the power supply, although the conversion efficiency of the transformer is high. Furthermore, since the two ends of the high and low resistance are formed first and then polarized, the polarization is difficult, and the yield is low. Therefore, the piezoelectric ceramic transformer needs to be further improved before it can be put into practical use.

In the past, piezoelectric ceramic transformers used a single sintered body. The driving end and the power generating end were prepared on the porcelain body. Due to the relatively high dielectric constant of the piezoelectric ceramic material, there was a strong gap between the driving end and the power generating end of the piezoelectric transformer. The electric coupling causes the high-voltage side and the low-voltage side to have large leakage currents that do not meet the insulation requirements; and because of the piezoelectric transformer of a single sintered body, the preparation of the ceramic body is completed at one time, making it impossible to arbitrarily adjust the drive and power generation ends. Layer-to-layer ratio Therefore, transformer changes cannot be adjusted very accurately. Especially on a single sintered ceramic body, a multilayer drive end and a multilayer power generation end must be prepared at the same time. The power generation end and the drive end are made of different materials according to design requirements. The preparation method is compared with that of a monolithic multilayer piezoelectric ceramic transformer. Structurally, the process is difficult.

In addition, in the process of making electronic ceramic materials, the sintering temperature is generally between 1150-i ³ oo ° c, and some are even higher. It has also been proposed that low-temperature sintering ceramic materials generate glass phases during the sintering process. Liquid phase sintering can be performed by melting and analyzing mass transfer processes, which can reduce the sintering temperature of the material, but these additives are all in the form of low-temperature glass. The individual crystal grains are bound to achieve the purpose of densification of the ceramic body, and a relatively thick grain boundary layer is formed at the grain boundaries at the later stage of sintering. However, due to the existence of these glass phases, the dielectric properties and piezoelectric performance parameters of ceramic materials are greatly reduced.

Furthermore, the traditional power supply circuit that converts AC power input to DC power output is inseparable from a circuit composed of a magnetic transformer, a semiconductor rectifier, and the like. Low-transformation-ratio piezoelectric ceramic transformer adopts electric energy-mechanical energy-electric energy conversion method. It has no reverse peak voltage, load protection short circuit, automatic protection cut-off, automatic recovery, high power density. It can be made into chip components to get rid of magnetic cores and wires. Reduced volume and other advantages. However, the commonly used piezoelectric vibrator drive circuit has its compensation inductor and piezoelectric element working in series, so the working voltage applied to the piezoelectric element is higher, the phase shift and surge current are larger, and the tube loss and reactive power are increased power.

Disclosure of invention

The main purpose of the present invention is to overcome the problem of poor insulation of a single sintered body piezoelectric ceramic transformer in the prior art, and to propose a process for transforming a non-single sintered body composite structure piezoelectric ceramic while using a low temperature sintered composite perovskite electronic ceramic material. Improve the dielectric voltage and electrical performance of piezoelectric ceramic transformer materials.

According to the prior art, the piezoelectric ceramic transformer has high conversion efficiency, but the power conversion efficiency Low problem, the inventor has adopted a special compensation circuit in order to make the inventor's piezoelectric ceramic transformer power supply circuit have higher conversion efficiency.

A composite structure piezoelectric ceramic transformer according to the present invention has no less than two driving terminals, one power generating terminal less than the number of driving terminals, and two times as many insulating sheets as the power generating terminals. The piezoelectric ceramic transformers with a multilayer composite structure are laminated on each other in sequence, and the outer surfaces of the first and last driving ends of the transformer are respectively connected with two insulating films. The components can be laminated in the following order: the first driving end, the first insulating sheet, the first power generating end, the second insulating sheet, the second driving end, the third insulating sheet, and the second Power generation end, 4th insulation sheet, 3rd drive end ... ηth drive end, 2η-1 insulation sheet, ηth power generation end, 2ηth insulation sheet, η + 1th drive end. The insulating film is located at the outer surfaces of the first driving terminal and the n-th driving terminal. In the present invention, the number of driving terminals is not more than ten.

The composite structure piezoelectric ceramic transformer according to the present invention may be welded, bonded or sintered at low temperature between the driving end, the power generating end and the insulating sheet.

Based on the multilayer piezoelectric ceramic transformer composed of the driving end, the insulation sheet and the power generating end of the present invention by bonding, the driving end is bonded by one to nine piezoelectric ceramic sheets coated with electrodes and polarized Together; the power generating end is bonded together by one to thirty pieces of piezoelectric ceramic sheets coated and polarized.

The method for manufacturing the above-mentioned multilayer piezoelectric ceramic transformer includes the following steps:

(1) Piezoelectric ceramic sheet molding: the required piezoelectric ceramic is processed into a sheet of a desired thickness, and its cross section perpendicular to the axial direction can be circular, regular polygon or rectangular; the driving end and the power generating end can use different piezoelectric Material

(2) Preparation of electrodes: The electrodes of the piezoelectric ceramic sheet can be produced by a high-temperature method or by electroplating or vacuum coating. The electrodes of the piezoelectric ceramic sheet are flat at both ends in the thickness direction. On the surface; polarizing the prepared piezoelectric ceramic sheet according to the requirements of the piezoelectric material used;

(3) Lamination bonding: the prepared piezoelectric ceramic sheets of various types are laminated according to the principle of opposite polarization directions, and are bonded to the driving end and the power generation by the adhesive according to the design requirements, respectively.

(4) Transformer molding: arranging the drive end, insulation sheet and power generation end in the order specified by the design, and bonding the transformer to form a transformer;

(5) Electrode connection: each piece of the driving end is connected in series or in parallel as an input terminal, and each piece of the power generating end is connected in parallel as an output terminal with different output characteristics; the process temperature of the external connection method should be higher than that of the piezoelectric material. The temperature is low ioo ^e c or more.

Based on a composite monolithic piezoelectric ceramic transformer according to the present invention, each of the driving end and the power generating end of the monolith is coated with an external electrode and then polarized. After the requirements are met, the driving end, the power generating end, and the insulating sheet are laminated. The method for manufacturing the composite monolithic piezoelectric ceramic transformer _c made of the composite monolithic structure includes the following steps:

(1) Diaphragm preparation: add piezoelectric ceramic powder to plasticizer which accounts for 10-30% of its weight, and make a uniform thickness on the film forming machine after mixing uniformly;

(2) Covering the internal electrode: After cutting the prepared film, the upper electrode is printed with palladium ~ genine electrode paste on a printing mechanism;

(3) Laminated molding: the membranes printed with internal electrodes are laminated in opposite directions to reach the number of layers required for the driving end and the power generating end, respectively, and then they are pressed up and down and around the pressure machine All sides are subjected to uniform pressure and pressed into the required body;

(4) Drying: Put the billet formed in step (3) into a drying box at a temperature of 8 l). C-120 ° (: drying for 6-48 hours; (5) Debinding: The billet dried in step (4) is put into a kiln for low-temperature and slow-temperature heating to vaporize and discharge the plasticizer. The low temperature is from 100 ° C to 350. C 止;

(6) High temperature sintering: The billet treated in step (5) is sintered in an industrial kiln. The material is ordinary pressure sintering, and the sintering temperature is 900. C-1 150. C, made of piezoelectric ceramic porcelain body;

(7) Covering the external electrode and polarization: After cooling the piezoelectric ceramic porcelain sintered in step (6) to room temperature, take it out for cleaning and cover the external electrode and place it at 120. C is polarized in a silicone oil at an electric field intensity of 3000 to 4500 volts / mm for 20 minutes, so that the electric domains in the porcelain body are oriented in the direction of the electric field;

(8) Detection and assembly: After the process (7) polarization, according to the design parameter parameters, after passing the inspection, perform assembly and assembly with the prepared insulation sheet in the following order:

First drive end, first insulation sheet, first power generation end, second insulation sheet, second drive end, third insulation sheet, second power generation end, fourth insulation sheet, third Drive ends ... analogously to the nth drive end, 2n-1 insulation sheet, η power generation end, 2η insulation sheet, η + 1 drive end, forming a composite structure piezoelectric ceramic transformer The outer surfaces of the first and last driving ends are respectively connected to two insulating films;

Adhesion, welding, or low-temperature sintering can be used between the drive end, power generation end, and insulation sheet.

The composite structure piezoelectric ceramic transformer of the present invention, specifically, the multilayer piezoelectric ceramic transformer and the composite monolithic piezoelectric ceramic transformer can both adopt a low-temperature sintered composite perovskite electronic ceramic material, that is, the total weight is 60-99. 7% lead-zirconate titanate containing strontium, niobium, magnesium, nickel ions and 0-10% of the total weight of sodium silicate as a basis, adding 0.1-1% of the total weight of oxidation, 0. 1-10% manganese dioxide and 0.1-10% cerium oxide to produce low-temperature sintered composite perovskite-type electronic ceramic materials, and its chemical formulation u wt [ ¹ Pb I "* Sr x (Nb„ / 3 Mg ° l / 3) 'y ( ^V Nb 2/3 Ni 1/3) ^y Z Zr w Ti 1-(y + _Z + w) O 3 ^J ]

+ R% wt Na ₂ Si0 ₃ + M% wt CdO + N wt Mn0 ₂

u = 60.0 -99.7 x = 0.00-0.05 y = 0.00-0.30

Z = 0.00-0.30 W = 0.10-0.35 R = 0.00-10.0 M- 0.10-10.0 N = 0.10-10.0 P = 0.10-10.0 where% wt represents weight percentage.

The method for manufacturing the low-temperature sintered composite perovskite-type electronic ceramic material of the present invention includes the following steps:

(1) Ingredients: Based on a composition containing 60% to 99.7% of lead zirconate titanate containing strontium, niobium, magnesium and nickel ions and 0 to 10% of total weight of sodium silicate. After a total weight of 0.1-10% cadmium oxide, 0.1-10% manganese dioxide and 0.1-10% cerium oxide, mix well;

(2) Pre-firing: After batching according to the above-mentioned step (1), put it into a heating furnace for pre-firing, and the pre-firing temperature gradually increases from low to 850. C-900 ^e C, so that the ingredient composition completes the solid phase reaction;

(3) Grinding: According to the step (2), the raw material after calcining is taken out and ground into powder;

(4) Molding: According to the step (3), the powder after grinding is processed into a shape according to the required shape;

(5) Sintering: The formed blank is sintered in a heating furnace. The material is ordinary pressure sintering, and the sintering temperature is 95 (TC-1050 ^e C), and a composite perovskite-type electronic ceramic material porcelain body is made;

(6) Polarization treatment: The sintered ceramic part is covered with an external electrode and polarized in a 120 ° C silicone oil at a field strength of 4 kV / mm for 20 minutes, so that the internal domains of the ceramic material are aligned in the direction of the electric field.

According to the present invention, a power supply circuit of a low-transformation piezoelectric ceramic transformer The power supply is provided with a rectifier and a DC conversion and voltage stabilizing circuit to provide a DC working power source for generating a square wave pulse width modulation generator and a half-bridge output circuit driver. The driver provides a MOSFET driving voltage of the half-bridge power amplifier and functions. The excitation voltage applied to the piezoelectric ceramic is applied to the excitation electrode, and an alternating piezoelectric signal is output from the secondary-side induction electrode of the piezoelectric ceramic, and a DC output is obtained after the rectification, filtering, and voltage stabilization circuit. The output square wave is set as a sine wave and added to the piezoelectric ceramic excitation electrode, and the third and fifth harmonic filter circuits composed of the inductance and capacitance of two series-connected parallel resonant circuits are used to reduce phase shift and reactive power. The compensating inductance coil for the inrush current is connected in parallel with the excitation electrode of the piezoelectric ceramic.

Other aspects of the present invention will be specifically described with reference to the drawings and embodiments.

Brief description of the drawings

FIG. 1 is a schematic structural diagram of a composite structure piezoelectric ceramic transformer according to the present invention; FIG. 2 is a schematic cross-sectional view of eight groups of internal electrodes and their bus electrodes of each layer of piezoelectric ceramic sheets at the power generating end in FIG. 1;

3 is a schematic cross-sectional view of the internal electrodes and the bus electrodes of group B of each layer of the piezoelectric ceramic sheet at the power generating end in FIG. 1;

4 is a schematic diagram of an embodiment of a plane expansion vibration mode n = 1 according to the present invention: FIG. 5 is a schematic longitudinal sectional view of a first embodiment of a multilayer piezoelectric ceramic transformer of the present invention;

6 is a schematic longitudinal sectional view of a second embodiment of a multilayer piezoelectric ceramic transformer of the present invention;

7 is a schematic structural cross-sectional view of a monolithic piezoelectric power generating end according to the present invention; FIG. 8 is a process flow diagram of manufacturing a composite monolithic piezoelectric ceramic transformer according to the present invention;

A 5 _ FIG. 9 is a manufacturing process flow chart of the low-temperature sintered composite perovskite-type electronic ceramic material of the present invention; FIG.

FIG. 10 is a schematic block diagram of a power supply circuit of a low-transformation ratio piezoelectric ceramic transformer according to the present invention. The best way to implement the invention

As shown in FIG. 1, the composite structure piezoelectric ceramic transformer of the present invention has more than two driving ends, and one power generating end and one insulating sheet having twice the power generating end than the driving end. Drive end 1-11, 1st insulation sheet 2-1, 1st power generation end 3-1, 2nd insulation sheet 2-2, 2nd drive end 1-2, 3rd insulation sheet 2-- 3. The second power generating terminal 3-2, the fourth insulating sheet 2-4, the third driving terminal 1-3 ... and so on to the nth driving terminal 1n, the 2n-1 insulating sheet 2 — 2n-1, the n-th power generation terminal 3-n, the 2n-th insulation sheet 2-2n, and the n + 1th drive terminal 1-n + 1 constitute a piezoelectric ceramic transformer with a multilayer composite structure. Among them, n ≤ 10, for plane expansion vibration mode n is best taken 1 to 4, and thickness direction vibration mode n is best taken 7-9.

The outer surfaces of the first and last drive ends of the transformer are connected to two insulation films 4-a and 4-b, respectively. And the driving end input end electrode is respectively provided. The drive end, power generation end, and insulation sheet can be combined by welding, bonding, or low-temperature sintering. As shown in FIG. 1, the driving terminals 1-1, 1-2 ······ 1-n are all piezoelectric ceramic sheets coated with external electrodes. Each driving end is led out in series or in parallel by a lead-out electrode. The polarization direction P is indicated by the arrow direction. The power generating end, the driving end, and the lead-out electrode of the insulating sheet are all shown by thick solid lines in the figure.

As shown in Figures 1, 2, and 3, the power generating terminals 3-1, 3-2 · · · · · · 3-n is a number of piezoelectric ceramic sheets of the same material to form a power generation group, or by the same or different Piezoelectric materials form multiple power generation groups; the internal electrodes 3A6 and 3B6 of each odd-numbered piezoelectric ceramic plate and the internal electrodes 3A5 and 3B5 of each even-numbered sheet are staggered and insulated from each other to form a group A internal power generator. The bus electrode 3A2 and the inner B bus electrode 381, and the inner A bus electrode 3B2 and the inner B bus electrode 3B1 constituting the group B of the power generation terminal; the polarization directions 3A4 or 3B4 of the adjacent piezoelectric ceramic sheets 3A3 or 3B3 are opposite to each other, each The generating set can be led out in parallel or in series, or separately.

The insulating sheet 2-1, 2-2 shown in FIG. 1 can be an inorganic membrane or a polymer composite membrane, and the surface thereof can be prepared with a driving current and an output current. electrode.

FIG. 4 shows an example of a concrete implementation of the composite structure piezoelectric ceramic transformer with the power generating terminal _n = 1. The axial cross section of the low-transformation-ratio piezoelectric ceramic transformer is approximately 26 mm in diameter and approximately 6 mm in thickness, and is a sheet-type piezoelectric ceramic transformer using a planar expansion mode.

As shown in Fig. 4, after the current is input through the two driving terminals (1-1, 1-2), mechanical vibration is generated at the driving terminal, and the generated mechanical vibration is transmitted to the two insulating plates (2-1, 2-2). ); The mechanical vibration is transmitted to the piezoelectric ceramic body of the power generating terminal 3-1 through the insulating sheet, and an electric field is generated, and the obtained ratio voltage is output through the bow I output electrode. Thus, the conversion process of electricity-mechanics-electricity is completed. In this example, the two drive terminals are connected in series, as shown in Figure 4.

Some of the main indicators are shown in the table below:

Insulation strength> 30 volts (AC effective value)

i all vibration frequency 86. O Hz

Output power〉 22. 0W

Best conversion efficiency> 90%

Weight Approx. 22 g

The above indicators are far superior to traditional small electronic transformers.

Adopting the composite structure piezoelectric ceramic transformer of the present invention has the following advantages:

(1) Miniaturization of power transformer can be realized. Because of the use of electrical energy-mechanical energy-electrical energy conversion

-IC- This type of piezoelectric ceramic transformer is free of the cores and coils of ordinary transformers.

(2) The voltage becomes relatively low. The relationship between input / output stages can be easily changed. The power generating end of the present invention converts stress waves of mechanical vibration into electric charge output, and each power generating unit is made into a multi-layer combination of a certain thickness according to the performance of the optional piezoelectric material and the required voltage and current to form a composite layer. According to requirements, the power generation end can be made into independent units with the same or different voltage and power outputs and compounded.

(3) There is a relatively high insulation strength between the levels, and an inter-level insulation layer with good insulation performance is used to meet the safety requirements.

(4) The safety protection function is good and the welding is convenient. The insulation film is used to insulate the driving end electrode from the housing or the mechanical external connection for insulation protection. At the same time, the driving end electrode is led out to a position convenient for welding.

In order to overcome the problems of unreliable insulation between high and low voltages of a single sintered body in the past and limited transformation ratio, a multi-layer piezoelectric ceramic transformer with a composite structure was proposed. However, there are still problems with complex molding processes, difficult to control inter-layer defects, and difficult to compound different materials. Therefore, the present invention provides a multilayer piezoelectric ceramic transformer as described below.

As shown in FIG. 5, the power generating end and the driving end of the multilayer piezoelectric ceramic transformer according to the present invention are composed of a piezoelectric ceramic sheet, an external electrode, an adhesive layer, and an external wire. With the driving end as a row, external electrodes were prepared on the piezoelectric ceramic sheets 101 and 102, respectively. The piezoelectric ceramic sheet 101, the adhesive ¹⁰² is completed before the polarization, the polarization direction thereof as shown by the arrows, opposite polarization directions of adjacent piezoelectric ceramic sheets. This is for the parallel use of piezoelectric ceramic plates to meet the requirements of different input voltages. 4-3 毫米。 Piezoelectric ceramic plate 101, 102 of the driving end is a type A piezoelectric ceramic material, high piezoelectric parameters and high loss under high voltage, its thickness is 0.4-3 mm.

The construction method of the power generation terminal is the same as that of the drive terminal. The purpose of the opposite polarization directions of adjacent piezoelectric ceramic plates is to avoid the mutual cancellation of charges, so as to obtain effective output power. The power generating end is composed of five piezoelectric ceramic sheets 301, 302, 303, 304, and 305, of which the class B material 301, 302, 303, 304 has the characteristics of providing a large current and reducing the output impedance; the class C material 305 has a relatively small Ε 33 and large d33, which are good for providing higher voltage and higher output impedance. As shown in FIG. 5, the external connection leads the piezoelectric ceramic sheet 3 (31, 302, 303, and 304 in parallel to form an output terminal 1 with a large output current; the external connection leads the C-type piezoelectric ceramic sheet 305 to constitute Output terminal 2 with higher output voltage.

The piezoelectric material A constituting the driving end has good piezoelectric characteristics under a high electric field to meet the requirements of high voltage driving. The piezoelectric ceramic plates 101 and 102 of the driving end are drawn in parallel by external wires to form an input terminal, as shown in FIG. .

The piezoelectric ceramic pieces of the driving end and the power generating end are combined into a whole through the bonding layers 501, 504, 505, 5ϋ6, and 507; the driving end, the power generating end, and the insulating sheet are combined into a multilayer piezoelectric through the bonding layers 502 and 503. Ceramic transformer.

This embodiment has been tested to make the axial cross-sectional area is circular, its diameter is about 25mm and its thickness is about 5. lmm. A B-type piezoelectric ceramic sheet having a thickness of 0.4 mm and a C-type piezoelectric ceramic sheet having a thickness of 0.8 mm constitute a dual output terminal. The thickness of the insulating sheet is 0.15mm. The transformer has a vibration mode of plane expansion, in which:

Main performance of Class A piezoelectric ceramics

Piezoelectric constant d33 320X10 Coulomb / Newton

Dielectric Constant ε 33 1300X8.85 χΐθ " ¹² Farads / meter

Curie temperature 284 ° C

Main performance of Class B piezoelectric ceramics

Piezoelectric constant d33 460X10 " ¹² Coulomb / Newton

Dielectric Constant ε 33 3400X8.85 X10 " ¹² Farads / meter

-ΙZZ- Curie temperature 280. C

Main performance of Class C piezoelectric ceramics

Piezoelectric constant d33 390X10 Coulomb / Newton

Dielectric Constant S 1400X8.85X10 Farad / meter

Curie temperature 263. C

The adhesive used was a modified epoxy resin with a curing temperature of 140 ° C. The main parameters of the piezoelectric ceramic transformer made by C are:

I all vibration frequency: 85.5 KHz

4-layer output power 18 W

Layer 1 output power 3.5 W

Maximum conversion efficiency〉 90%

Weight 15 g

Peak input voltage <500 V

FIG. 6 is a schematic structural diagram of a multilayer piezoelectric embodiment 2 of the present invention. The same parts as those in FIG. 5 are shown with the same reference numerals, and will not be described in detail. Among them, 10x indicates the serial number of the piezoelectric ceramic chip at the driving end; 30x indicates the serial number of the power generating terminal; 50x indicates the serial number of the bonding layer. For higher output power requirements, the driving end can be composed of 9 pieces of class A piezoelectric ceramic materials with a thickness of 0.4mm. The main parameters are:

Piezoelectric constant d ³³ 280X10 Coulomb / Newton

Dielectric constant ε 33 800X8.85X10 ¹² Farad / meter

The power generation terminal consists of 2 "7 pieces of Class B piezoelectric ceramic materials with a thickness of 0.2mm and 2 pieces of Class C piezoelectric ceramic materials with a thickness of 0.5mm. The main parameters of piezoelectric material B are:

Piezoelectric constant d33 460X10 Coulomb / Newton Dielectric Constant £ "33 3400X8.85 X10— 'Farad / meter

The main parameters of Class C piezoelectric materials are:

Piezoelectric constant d33 320X10 " ¹² Coulomb / Newton

Dielectric Constant S 1300X8.85 X10 " ¹² Farads / meter

They constitute a 29-chip power generator.

The driving end and the power generating end are respectively bonded by a modified epoxy resin, a modified phenolic resin, and the like, and the curing process temperature thereof is 120 ° C / ² hours or 150 ° C / 2 hours. The two driving ends are respectively bonded to the two ends of the power generating end through insulating sheets 2-1, 2-2, and the piezoelectric ceramic sheets of the two driving ends are led out in parallel by external wires. As shown in FIG. 6, the power generation terminal is led out in parallel by 27 pieces of B-type piezoelectric ceramic pieces through external wires to constitute a high-power output terminal, and the C-type piezoelectric ceramic piece is drawn out in parallel through external wires to form a voltage output terminal.

After testing, the vertical axial cross-section has been made into a regular hexagon, its outer circle diameter is 30mm, the driving end is composed of two 9-layer piezoelectric ceramic sheets with a thickness of 0.4mm, and the power generating end is composed of 27 B-type piezoelectric materials. And 2 types of piezoelectric ceramic transformers with a total thickness of 14.8mm for Class C piezoelectric materials, the main parameters are:

Resonant frequency 71.5 KHz

Power output

Output power 95 W

Voltage output

Output power 25V / 0.15A

Weight 82 g

The advantages and positive effects of the multilayer piezoelectric ceramic transformer of the present invention are: (1) the molding process is simple, and the inter-layer defects are easy to control, which avoids the defect of a single layer after molding in the existing technology causing the overall failure; 2) Multilayer piezoelectric ceramic transformer of the present invention and manufacturing method thereof

- 'Cattle- The shortcomings of different materials in the prior art are difficult to be overcome; (3) the present invention overcomes the limitation of material selection caused by the piezoelectric materials that must be sintered in the prior art, and the performance of the present invention is improved; ( ⁴ ) because Without the internal electrode, the positive effect of the present invention is to avoid the method of providing expensive palladium-silver electrode in the multilayer sintered body of the prior art composite piezoelectric ceramic transformer, which not only simplifies the manufacturing process, but also particularly cheap.

The basic structure of the piezoelectric ceramic transformer of the composite monolithic structure of the present invention is substantially the same as that shown in FIG. 1 and will not be described in detail here. Figure 7 shows the cross-sectional structure of the monolithic piezoelectric body (power generation end). The membranes covered with the internal electrodes are superimposed in a direction opposite to each other, and the lead-out electrodes shown by thick solid lines are used to apply a polarized electric field after the superposition. Shown polarization direction. Those skilled in the art should know that the composition and polarization of each piezoelectric ceramic plate in the driving end of the composite monolith is also the same as that of the power generating end. This will be further explained in conjunction with the manufacturing process of the composite monolithic piezoelectric ceramic transformer of the present invention.

As shown in FIG. 8, the manufacturing steps of the manufacturing method of the composite monolithic piezoelectric ceramic transformer according to the present invention are as follows:

(a) Diaphragm forming: The piezoelectric ceramic powder material is added to a plasticizer which accounts for 25% of its weight, and mixed and hooked to form a diaphragm with a thickness of 0.05 to 3.00 mm on a film forming machine. Under a certain design requirement, the optimal parameter thickness of the driving end is 0.52 mm and the number of layers is 3 layers; the optimal parameter thickness of the power generating end is 0.35 mm and the number of layers is 9 layers;

(b) Covering the internal electrode: The above-mentioned membrane is cut into a circle, a regular polygon or a square according to the design requirements, and the internal electrode is printed on the printing machine with a palladium-silver internal electrode paste;

(c) Lamination molding: the membranes covering the internal electrodes are laminated in the opposite direction to each other to reach the number of layers required by the design, and then they are supported on the isostatic press and on the sides of the periphery. Formed under uniform pressure;

(d) Drying: Put the formed blank into a drying box at a temperature of 100 ° C. Dry at C for 24 hours;

(e) Debinding: Put the dried material into a box kiln from a low temperature of 100 ° C. C is raised to 350 ° C to vaporize the plasticizer.

(f) High-temperature sintering: The above-mentioned blank is sintered in an industrial kiln, and the driving end and the power generating end are fired at 1000 ° C and 1080 ^e C, respectively, into a monolithic piezoelectric ceramic body;

(g) Covering the external electrode and polarization: cooling the sintered piezoelectric ceramic porcelain body to room temperature, covering the silver external electrode; placing it in 120 ^e C silicone oil for 20 minutes at 4500 V / mm electric field strength, so that The electric domains of the ceramic body form an arrangement opposite to each other in the direction of the electric field;

(h) Detection and assembly: Assemble and assemble the piezoelectric ceramics that have passed the above-mentioned polarization tests in the order shown in Figure 1.

The following gives some main test data of a concrete example of a composite monolithic piezoelectric ceramic transformer made of the composite monolithic piezoelectric ceramic transformer of the present invention when n = 1.

Input voltage: Vi. Rms 70 volts

Output voltage: Vo. Rms 17 volts

Output current: Io. Rms 1. 5 amps

Output power: P 25. 5 watts

Conversion efficiency: V> 90% Insulation resistance: R / lOOv> io ¹⁰ ohm

Insulation voltage: VB. Rms> 3750 volts for 1 minute The advantages of the composite monolithic piezoelectric ceramic transformer of the present invention are: As a result of using the method of manufacturing the composite monolithic piezoelectric ceramic transformer of the present invention, the pressure of a single sintered body is overcome The strong electrical coupling between the driving end and the generating end of the electric ceramic transformer is used.

-ι'ί- The high voltage side and low voltage side have large leakage currents and poor insulation performance. It also overcomes the disadvantage that the transformer ratio cannot be adjusted accurately; especially on a single sintered ceramic body, it is necessary to prepare a multilayer drive end and The multi-layer power generation terminal, which is separately prepared from the driving terminal and the power generating terminal of the present invention, is far more difficult than the present invention in terms of process. The product made by the manufacturing method of the composite monolithic piezoelectric ceramic transformer of the present invention achieves a composite monolithic porcelain body that is like a single piece of porcelain after sintering multiple layers, and a piezoelectric ceramic made by this method. Transformer has simple manufacturing process, high manufacturing precision, miniaturization, and low voltage transformation ratio, especially the driving end and power generating end can be made of different piezoelectric materials, which is a prominent improvement for existing piezoelectric ceramic transformers. .

The low-temperature sintered composite perovskite electronic ceramic material designed according to the present invention can reduce the sintering temperature, improve the dielectric and piezoelectric properties of the material, and reduce energy consumption during the sintering process.

As shown in FIG. 9, the manufacturing process of the low-temperature sintered composite perovskite electronic ceramic material of the present invention is as follows:

1 'Batching: Dosing according to the percentage by weight, first take 60%-99.7% of lead zirconate titanate containing strontium, niobium, magnesium and nickel ions and 0-10% of sodium silicate Based on the composition, after adding a total weight of 0.1 to 10% of cadmium oxide, 0.1 to 10% of manganese dioxide and 0.1 to 10% of cerium oxide, mix well;

2 'Pre-firing: After the ingredients are mixed according to the procedure (1'), put them into a heating furnace for pre-firing, and the pre-firing temperature gradually increases from low to 850 ° C-900 ° C, so that the ingredients composition completes the solid phase reaction;

3 'Grinding: According to the process (2'), the pre-fired blank is taken out and ground into powder;

4 'Molding: According to the process (3'), the powder is ground and shaped according to the required shape;

5 'Sintering: Put the formed billet into a heating furnace for sintering. The material is ordinary pressure sintering, and the sintering temperature is 950'C-1050 ^e C. It is made into composite perovskite electronic ceramic material; 6 'polarization treatment: The sintered ceramic part is covered with an external electrode and polarized in a 120 C silicone oil at a field strength of 4 kV / mm for 20 minutes, so that the internal domains of the ceramic material are aligned in the direction of the electric field.

The chemical formula of the present invention is:

U% Wt [Pb ^ Sr (Nb _2/3 Mg _{i / 3} ) _y (Nb _2/3 Ni _{i / 3} ) ZrJi _i . _{(Y + i + w} 0 ₃ ] + R% Wt Na Si0 ₃ + M% Wt CdO + N Wt MnO, + P% Wt CeO _{; The} best example of comprehensive performance:

u = 89.1% X = 0.05 Y = 0.10

Z = 0.175 W = 0.35 R = 0.10

M = 3.30 N = 3.00 P = 4.50

And get the chemical configuration of the example:

89 l% Wt i lP ^A b 0.95 Sr 0.05 (Nb 2/3 Mg ° 1/3) 0.1 (, Nb 2/3 Ni 1/3), 0.175 Zr 0.35 Ti 0.375 O 3] ^J

+ 0.1 Wt Na, Si0 ₃ + 3.3 WtCdO + 3% Wt Mn0 ₂ + 4.5% WtCe0 _{2 To} prepare a ceramic material with a molecular weight of 1 gram, you must first prepare zirconium containing strontium, niobium, magnesium and nickel ions in the above chemical formula Lead titanate is prepared by conventional methods with the following dosages with the same weight and chemical composition:

PbO 212.04 g

SrO 5.18g

MgO 1.34g

Nb 205 21.45 g

NiO 4.36g

Zr〇, 43.13 g

TiO '30.00 g

-is- The total weight is 317.5 grams, accounting for 89.1% of the total weight.

Then take the additives

Na ₂ Si0 ₃ 0.36 g

CdO 11.76g

Mn0 ₂ 10.69 g

Ce0 ₂ 16.0 g

The total weight is 38.85 grams, accounting for 10.9% of the total weight.

After mixing the above items, a ceramic material having a molecular weight of 1 gram was obtained through the process steps shown in FIG. 9. With reference to the above proportions, a ceramic material with a desired weight can be produced.

As shown in FIG. 9, the ⁴ ingredients' is composed of 317.5 g of lead zirconate titanate containing strontium, niobium, magnesium, and nickel ions, accounting for 89.1% of the total weight; additives Na ₂ Si ₃ , CdO, Mn0 ₂ , CeO It weighs 38.85 grams, accounting for 10.9% of the total weight. After ⁴ burn-in, warm to 850. (: -900. (: And drying, to 860. (:-870. (: better. After 'grinding,' molding ', and then' sintering ', heating 950 ^e C-1050. C It is preferably 1020 ° C to 1050 ° C. Further, the 'polarization treatment' enables the internal electric domains of the ceramic material of this embodiment to be aligned in the direction of the electric field.

At temperature io ⁵ o. After sintering at C, the main properties of the ceramic material of this embodiment after polarization are as follows:

Material density P 7.75 g / cm3

Frequency constant N 2300 Hertz-meter dielectric constant f 3200X8.85X10 ^1: Farad / meter dielectric loss tgS 70X10 Piezoelectric constant d ₃₃ ⁴⁶ 0X 10— ^1: Coulomb / Newton Electromechanical coupling coefficient Kp 0.60

Mechanical figure of merit Qm 600

Pozambin. 0.36

In order to compare the above performance indicators, the inventors substituted the aforementioned numerical ranges given by the values of the coefficients to be determined (U, X, Y, Z, W, R, M, N, P) according to the chemical formula of the present invention, and tested The obtained material is sintered at 1050 ° C. According to the selection of different chemical ratios, the main properties of the material after polarization are as follows:

Material density P 7.60-8.10 g / cm3

Frequency constant N 2000-2500 Hz

Dielectric constant ε (800-3400) X8.85 X10 ^_1: Farad / meter dielectric loss tgS (50-100) X10 " ⁴ Piezoelectric constant d ₃₃ (250-550) X 10 ¹² Coulomb / Newton

Electromechanical coupling coefficient Kp 0.55 -0.70

Mechanical figure of merit Qm 400-1000

Pozambin G 0.34 -0.38

The advantages of the composite perovskite-type electronic ceramic material of the present invention are:

1. Reduced sintering temperature. In the present invention, chemical additives are added to the ceramic body during the sintering process to produce a liquid phase component, and liquid phase sintering is performed to reduce the sintering temperature.

2. Improve the dielectric and piezoelectric performance of piezoelectric materials. The chemical composition of the liquid phase components produced by the present invention is perovskite-like, with certain dielectric and piezoelectric properties; in the later stage of sintering, a considerable portion of the added components can Compounded in the main crystalline phase structure to form a composite perovskite type structure, which can better play the role of the main crystalline phase and greatly reduce energy and hair loss.

According to the present invention, a power supply circuit for a low-transformation piezoelectric ceramic transformer is rid of Magnetic core and coil, select the inverter power amplifier circuit, which works with square wave in pulse width modulation state to reduce tube consumption, and the piezoelectric element works in sine wave mode to reduce reactive power and inrush current .

As shown in the principle block diagram shown in FIG. 10, the AC power source 1 is the city power grid AC. Rectifier 2 is composed of two sets of bridge semiconductor rectifiers B1 and B2. The DC conversion and voltage stabilization circuit 3 is a DC working power source for providing the pulse width modulation generator 4 and the driver 5 of the half-bridge output circuit. The driver of the half-bridge output circuit, 5, specifically provides M1, M2, which are the driving voltage of the half-bridge output amplifier MOSFET (metal oxide field effect transistor) 6, 7. Referring to FIG. 10, the gates G of the two transistors of the output amplifiers MOSFETs 6, 7 are respectively added; the half-bridge power output circuit is composed of the power amplifiers MOSFETs 6, 7 and half-bridge capacitors 14, 15. The source S of the MOSFET 6 and the drain D of the MOSFET 7 are connected to form a contact 19 of the bridge, and the half-bridge capacitor 14 and the half-bridge capacitor 15 are connected to form the other contact 20 of the bridge. The contact I ^{9 is} connected to one end of the piezoelectric ceramic excitation electrode 801, and the contact -20 is connected in series with two parallel resonant circuits, that is, a third and fifth harmonic filter circuit composed of an inductor 9, a capacitor 10 and an inductor 11, and a capacitor 12. The square wave output from the half bridge is set as a sine wave and is applied to the other end of the excitation electrode 801 of the piezoelectric ceramic transformer 8. The compensation inductor 13 is connected in parallel with the excitation electrode 801, which compensates the phase shift caused by the electrostatic capacitance of the piezoelectric element, and reduces the total current phase shift and the energy consumption of reactive power and inrush current. The alternating voltage generated by the piezoelectric effect of the secondary-side induction electrode 802 of the piezoelectric ceramic transformer 8 passes through the rectifying and filtering voltage stabilization circuit 16 shown in FIG. 10, and obtains a DC voltage stabilization output 17. The voltage-stabilized feedback signal of this circuit is constituted by a feedback 18 of a photocoupler, and the output square wave of the pulse width modulation generator 4 is modulated to achieve the purpose of voltage stabilization.

The advantages of the power supply circuit of the piezoelectric ceramic transformer with low transformation ratio of the present invention are as follows: (1) An inverter power amplifier circuit is designed, and the circuit works with a square wave in a pulse width modulation state to reduce tube consumption. (2) The piezo element works in a sine wave mode because it outputs a half bridge The two sets of parallel resonant circuits of inductors and capacitors whose square wave is set to a sine wave form a third and fifth harmonic filter circuit, so it can reduce reactive power and inrush current. (3) The compensation inductor coil is connected in parallel with the excitation electrode of the piezoelectric ceramic, which compensates the phase shift caused by the electrostatic capacitance of the piezoelectric element, and reduces the total current phase shift and the energy consumption of reactive power and surge current. (4) The magnetic core and the wire coil of the traditional transformer power supply circuit are eliminated, the size of the instrument is reduced, there is no reverse peak voltage, the load short circuit is automatically cut off and automatically restored, and the power density is high. (5) The electric energy-mechanical energy-electric energy conversion method is adopted, and the piezoelectric ceramic transformer can be made into a chip component, and the transformation ratio can be selected.

Industrial applicability

1. Low-ratio piezoelectric ceramic transformers made of piezoelectric ceramic materials can reduce the size and size of power transformers for high-frequency switching power supplies. The transformer has high power density, high conversion efficiency, no reverse peak voltage, and has the advantages of automatic load short circuit protection, automatic recovery, small size, light weight and so on.

2

It has the advantages of low sintering temperature, small grain boundary thickness after monolithization, and high piezoelectric performance. It has good practicability.

3. Low-transformation-ratio piezoelectric ceramic transformers have high insulation strength, reasonable structural design, good mechanical matching between levels, accurate measurement of electrical external characteristics, and clear correlations, which is convenient for practical applications.

4. AC-DC power converters made of low-transformation piezoelectric ceramic transformers have the advantages of small size, light weight, and ultra-thin type. They are widely used in various computers, communication equipment, instruments, meters and special occasions. Application, the market prospect is broad.

5. The manufacturing process of the low-transformation piezoelectric ceramic transformer is mature, and it can be transformed with the current electronic ceramic production technology and equipment to enable large-scale industrial production. Claim

A piezoelectric ceramic transformer with a composite structure, characterized in that the piezoelectric ceramic transformer has no less than two driving terminals, one power generating terminal less than the number of driving terminals, and two insulation sheets twice in number as the power generating terminals, wherein The components are sequentially stacked on top of each other to form a multilayer composite piezoelectric ceramic transformer, and the outer surfaces of the first and last driving ends of the transformer are respectively connected to two insulating films (4-a, 4-b).

2. The piezoelectric ceramic transformer with a composite structure according to claim 1, characterized in that the components are laminated in the following order:

The first drive end (1-1);

The first insulating sheet (2-1);

The first power generation terminal (3-1);

The second insulating sheet (2-2);

The second driving end (1 to 2);

The third insulating sheet (2-3);

The second power generation terminal (3-2);

The fourth insulation sheet (2-4);

3rd driving end (1 to 3); nth driving end (1 to n);

2n-1 insulating sheet (2-2n-1);

The nth power generation terminal (3-n);

The 2ηth insulating sheet (2-n);

The n + 1 driving end (3-n + 1).

-Zί- 3. The composite structure piezoelectric ceramic transformer according to claim 2, wherein the natural number n is not greater than 10.

4. The piezoelectric ceramic transformer with a composite structure according to claim 1 or 2, characterized in that the driving terminal, the power generating terminal, and the insulating sheet can be welded or bonded at low temperature.

5. The composite structure piezoelectric ceramic transformer according to claim 1 or 2, characterized in that the driving ends are all piezoelectric ceramic sheets coated with external electrodes, and each driving end is led out in series or in parallel by the lead-out electrodes.

6. The composite structure piezoelectric ceramic transformer according to claim 1 or 2, characterized in that each of the power generating terminals (3-1, 3-2, ··· 3-n) is made of several piezoelectric materials of the same material. The sheets form a power generation group; the inner electrodes (3A6, 3B6) of each odd-numbered piezoelectric ceramic sheet and the inner electrodes (3A5, 3B5) of each even-numbered piezoelectric ceramic sheet are staggered, insulated from each other, and form a bus in the power generation group A Electrode (3A2) and inner B bus electrode (3A 1), and inner bus bar electrode (3B2) and inner B bus electrode (3B1) constituting group B of power generation terminal; polarization of adjacent piezoelectric ceramic sheets (3A3, 3B3) The directions (3A4, 3B4) are opposite, and each generating group can be connected in parallel, series or separately.

7. The composite structure piezoelectric ceramic transformer according to claim 1, 2 or 6, characterized in that each of the power generating terminals (3-1, 3--2, 3-n) can also be made of different and different piezoelectric The material forms multiple power generation groups.

8. The piezoelectric ceramic transformer with a composite structure according to claim 1 or 2, characterized in that the insulating sheet (2-1, 2-2) can be an inorganic diaphragm or a polymer composite diaphragm, and The surface is provided with a lead-out electrode for driving the current at the drive end and for deriving the output current.

9. The piezoelectric ceramic transformer with a composite structure according to claim 1 or 2, characterized in that an axial cross section of the piezoelectric ceramic sheet at the driving end and the power generating end can be any geometric shape. 10. A multilayer piezoelectric ceramic transformer formed by bonding a driving end, an insulating sheet and a power generating end, characterized in that the driving end is bonded by one to nine piezoelectric ceramic sheets coated with electrodes and polarized. Together; the power generating end is bonded by one to thirty piezoelectric ceramic sheets that are coated and polarized.

11. The multilayer piezoelectric ceramic transformer according to claim 10, characterized in that the power generating end can be bonded by piezoelectric materials of different materials or different thicknesses, and the piezoelectric materials of different materials or different thicknesses The thin films respectively constitute a plurality of output terminals to meet the requirements of different output characteristics; the electrodes of the piezoelectric ceramic sheets constituting the different output terminals are respectively led out in parallel through external wires.

12. The multilayer piezoelectric ceramic transformer according to claim 10, characterized in that the driving end is made of piezoelectric ceramic sheets of the same material and the same or different thickness, and the electrodes of each piezoelectric ceramic sheet are respectively connected by external wires. Lead out.

13. —A method for manufacturing a multilayer piezoelectric ceramic transformer: It is characterized by including the following steps:

Piezoelectric ceramic sheet forming: the required piezoelectric ceramic porcelain body is processed into a sheet of a desired thickness, and the driving end and the power generating end can use different piezoelectric materials;

Preparation of electrodes: The electrodes of piezoelectric ceramics can be produced by high temperature method or by electroplating and vacuum coating. The electrodes of piezoelectric ceramics are located on the planes at both ends in the thickness direction. A good piezoelectric ceramic sheet is laminated according to the principle of opposite polarization directions, and is bonded to the driving end and the power generating end by an adhesive according to the design requirements. The curing temperature of the adhesive should be much lower than the piezoelectric ceramic material used. Curie temperature; Transformer molding: the drive end, the insulation sheet and the power generation end are bonded by an adhesive in the order specified by the design to form a transformer; Electrode connection: the pieces at the drive end are connected in series or in parallel as input terminals, and the pieces at the power generation end are connected in parallel as output terminals with different output characteristics; the process temperature of the external connection method should be lower than the Curie temperature of the piezoelectric material. 'c or more.

14. The method for manufacturing a multilayer piezoelectric ceramic transformer according to claim 13, wherein the piezoelectric ceramic sheet has a cross section perpendicular to the axial direction, which may be circular, regular polygon, or rectangular.

15. The method for manufacturing a multilayer piezoelectric ceramic transformer according to claim 13 or 14, characterized in that when multiple sets of outputs are required and the output requirements are different, the piezoelectric thin film at the power generating end is processed into different thicknesses or different materials are selected.

16. The method for manufacturing a multilayer piezoelectric ceramic transformer according to claim 13, characterized in that said adhesive is usually bonded with modified epoxy, modified phenolic, modified urea, polyimide or acrylic Agent.

17. A composite monolithic piezoelectric ceramic transformer, characterized in that each driving end and power generating end prepared separately have a monolithic structure, and each piezoelectric ceramic body is covered with an external electrode, and meets requirements for driving after being polarized. End, power generation end and insulation sheet for composite assembly.

18. A manufacturing method of a composite monolithic piezoelectric ceramic transformer, characterized in that it includes the following steps:

Diaphragm preparation (a): Add piezoelectric ceramic powder to plasticizer which accounts for 10-30% of its weight, and make a uniform thickness on the film forming machine after mixing uniformly;

Covering the internal electrode (b): printing the upper electrode on the printing machine with palladium-silver internal electrode paste on the printing machine after cutting the film;

Lamination molding (c): The membranes printed with internal electrodes are laminated in opposite directions to reach the number of layers required for the driving end and the power generating end, respectively, and then they are pressed up and down and around the machine All sides are subjected to the pressure of the hook, and pressed into the required body; Drying (d): Put the billet formed in step (c) into a drying box at a temperature of 80. C-120. (: Drying for 6-48 hours;

Debinding (e): Put the dried material in step (d) into a kiln for low temperature and slow temperature rise to vaporize the plasticizer. The low temperature is from 100 ° C to 350 ° C. C 止;

(6) High-temperature sintering (e): The billet processed in step (5) is sintered in an industrial kiln. The material is ordinary pressure sintering, and the sintering temperature is 900. C-1150 ^e C, made of piezoelectric ceramic porcelain body;

Covering the external electrode and polarization (g): After the process (0 sintered piezoelectric ceramic porcelain body is cooled to room temperature, take it out for cleaning, cover the external electrode, and place it in a silicone oil at 120 ° C at 3000-4500 Volt / mm electric field intensity was polarized for 20 minutes, so that the electric domains in the porcelain body were aligned in the direction of the electric field;

Inspection and assembly (h): After the process (g) polarization, according to the design parameters, after passing the inspection, the assembled assembly is assembled in the following order with the prepared insulation sheet:

First drive end, first insulation sheet, first power generation end, second insulation sheet, second drive end, third insulation sheet, second power generation end, fourth insulation sheet, third drive end ... … And so on to the n-th driving end, the 2η-1 insulating sheet, the η generating end, the 2η insulating sheet, and the η + 1 driving end, in order to form a composite structure piezoelectric ceramic transformer. Its first The outer surfaces of the first and last driving ends are connected to two insulating films respectively;

Adhesion, welding, or low-temperature sintering may be used between the driving end, the power generating end, and the insulating sheet.

19. A method for manufacturing a piezoelectric monolithic piezoelectric ceramic transformer according to claim 18, wherein the natural number η is not greater than 10.

20. The method for manufacturing a composite monolithic piezoelectric ceramic transformer according to claim 18, characterized in that the formed blank is placed in a dry box at a temperature of 100 ° C Dry for 24 hours.

21. The manufacturing method of a composite monolithic piezoelectric ceramic transformer according to claim 18, characterized in that said billet is sintered in an industrial kiln, and the driving end and the generating end are respectively 1000. C and 1080 ° C fired into monolithic piezoelectric ceramic porcelain.

22. A low-temperature sintered composite perovskite-type electronic ceramic material for manufacturing a piezoelectric ceramic transformer according to claim 1, 10, and 17, characterized in that: it contains strontium and niobium by 60-99.7% of the total weight Based on the composition of lead, zirconate titanate, magnesium, nickel ions and sodium silicate, which accounts for 0-10% of the total weight, add 0.1-10% of cadmium oxide, 0.1-10% of manganese dioxide and 0.1-10% cerium oxide produces low-temperature sintered composite perovskite electronic ceramic materials, and its chemical formula is:

u% wt [Pb _ _x Sr _x (Nb _2/3 Mg _{i / 3} ) _y (; ^! ^ +.

+ R% wt Na, Si〇 ₃ + M% wt CdO + N% wt Mn0 ₂

u = 60.0— 99.7 x = 0.00-0.05 y = 0.00-0.30

Z = 0.00 -0.30 W = 0.10-0.35 R = 0.00-10.0 M = 0.10-10.0 N = 0.10-10.0 P = 0.10—10.0 where% wt means weight percentage.

23. A method for manufacturing a low-temperature sintered composite perovskite-type electronic ceramic material, comprising the following steps:

Ingredients (1 '): Based on a composition containing 60%-99.7% of the total weight of lead zirconate titanate containing strontium, niobium, magnesium, and nickel ions and 0-10% of the total weight of sodium silicate, by adding 0.1 to 10% of the total weight of the oxide, 0.1 to 10% of manganese dioxide and 0.1 to 10% of cerium dioxide, mix well;

Pre-firing (2 '): After batching according to the procedure (1'), put it in a heating furnace for pre-firing, and the pre-firing temperature gradually increases from low to 850 ° C-900 ° C, so that the batch composition completes the solid phase reaction. ; Grinding (3 '): Pre-sintered billet according to process ( ² '), take out processing and grinding into powder; Molding (4 '): Milled powder according to process (3'), shape required by Lennon Processing and molding; Sintering (5 '): Put the formed billet into a heating furnace for sintering. The material is ordinary pressure sintering, and the sintering temperature is 950 ° C-1050 ° C. The composite perovskite electronic ceramic material is made. ;

Polarization treatment (6 '): The sintered ceramic part is covered with an external electrode at 120 °. The C silicone oil was polarized at a field strength of 4 kV / mm for 20 minutes, so that the electric domains in the ceramic material were aligned in the direction of the electric field.

24. A power supply circuit using a piezoelectric ceramic transformer with a low transformation ratio as claimed in claim 1, 10, and 17 wherein an AC power source (1) is passed through a rectifier (2) and a DC conversion and voltage stabilization circuit ( 3) A DC working power supply for generating a square-wave pulse width modulation generator (4) and a driver (5) for the half-bridge output circuit. The driver (5) provides a half-bridge power amplifier (6, 7). The driving voltage of the MOSFET is generated, and the excitation voltage applied to the piezoelectric ceramic (8) is added to the excitation electrode (801), and the output alternating piezoelectric signal is generated from the secondary end induction electrode (8G2) of the piezoelectric ceramic (8). The rectifying, filtering and stabilizing circuit (16) obtains a DC output (17), which is characterized in that the square wave output from the half bridge is set to a sine wave and added to the piezoelectric ceramic excitation electrode (801). Inductor (9), capacitor (10) of the parallel resonance circuit, and third and fifth harmonic filter circuits composed of inductor (11) and capacitor (12); compensation inductance to reduce phase shift, reactive power and inrush current The wire coil (13) is connected in parallel with the excitation electrode (801) of the piezoelectric ceramic (8) .

- 2? -

Claims

Date of receipt of amended claims: April 10, 1996 (10.04.96); Original claims 1-24 replaced with claims 1-29 (8 pages total)

1. A scale composite structure piezoelectric ceramic transformer, characterized by having no less than two driving terminals, one power generating terminal less than the number of driving terminals, and two times the number of insulating sheets as the power generating terminals, wherein The components are stacked on top of each other in the vertical direction in order of the driving end, the insulation sheet, the power generation end, the insulation sheet, the driving end, the insulation sheet, the power generation end, ... transformer.

2. The piezoelectric ceramic transformer with a composite structure according to claim 1, characterized in that the outer surfaces of the first and last driving ends of the transformer are connected to two insulating films (4-a, 4-b), respectively. .

3. The piezoelectric ceramic transformer with a composite structure according to claim 1, characterized in that the number of the power generating terminals is not more than ten.

4. The piezoelectric ceramic transformer with a composite structure according to claim 1, characterized in that the driving terminal, the power generating terminal, and the insulating sheet can be welded or bonded at low temperature.

5. The piezoelectric ceramic transformer with a composite structure according to claim 1, wherein the driving ends are all piezoelectric ceramic sheets coated with external electrodes, and each driving end is led out in series or in parallel by a lead-out electrode.

6. The piezoelectric ceramic transformer with composite structure according to claim 1, characterized in that each power generating end (3-1, 3-2, -3-n) is composed of a plurality of piezoelectric sheets of the same material to generate a power The internal electrodes (3A6, 3B6) of each odd-numbered piezoelectric ceramic sheet and the internal electrodes (3A5, 3B5) of each even-numbered piezoelectric ceramic sheet are staggered and insulated from each other to form a group A inner electrode bus electrode (3 A2) ) And inner-B bus electrode (3 A 1), and the inner-A bus electrode (3B2) and inner-B bus electrode (3B1) constituting the group B of the power generation terminal; the polarization directions of adjacent piezoelectric ceramic sheets (3A3, 3B3) ( 3A4, 3B4) Conversely, each generating unit can Lead out in series or separately.

7. The composite structure piezoelectric ceramic transformer according to claim 1 or 6, characterized in that each of the power generating terminals (3-1, 3-2, 3-n) can also be made of different and different piezoelectric materials. Form multiple power generation groups.

8. The piezoelectric ceramic transformer with a composite structure according to claim 1, characterized in that the insulating sheet (2-1, 2-2) can be an inorganic membrane or a polymer composite membrane, and is prepared on the surface thereof. There are lead-out electrodes that lead in the drive-end current and lead-out the output current.

9. The piezoelectric ceramic transformer with a composite structure according to claim 1, wherein an axial cross-section of the piezoelectric ceramic sheet at the driving end and the power generating end can be any geometric shape.

10. A piezoelectric ceramic transformer with a composite structure, comprising at least two driving terminals, one power generating terminal less than the number of driving terminals, and two times as many insulating sheets as the power generating terminals, wherein The components are stacked on top of each other in the vertical direction in the order of the driving end, the insulating sheet, the power generating end, the insulating sheet, the driving end, the insulating sheet, the power generating end, ..., and by bonding to form a multilayer piezoelectric ceramic transformer; The driving end is bonded by one to nine pieces of piezoelectric ceramics covered with electrodes and polarized; the power generating end is one to thirty pieces of piezoelectric ceramics covered with electrodes and polarized The pieces are glued together.

11. The piezoelectric ceramic transformer with a composite structure according to claim 10, characterized in that the outer surfaces of the first and last driving ends of the transformer are respectively connected with two insulating films.

12. The piezoelectric ceramic transformer of composite structure according to claim 10, wherein the piezoelectric ceramic sheets of different materials or different thicknesses respectively constitute a plurality of output terminals to meet the requirements of different output characteristics; Output terminal of piezoelectric ceramic sheet The electrodes are led out in parallel through external wires.

13. The piezoelectric ceramic transformer with a composite structure according to claim 10, wherein the electrodes of each piezoelectric ceramic sheet are respectively drawn by external wires.

14. A method for manufacturing a piezoelectric ceramic transformer with a composite structure, comprising the following steps:

Electrode preparation: silver electrode can be prepared by high temperature method or electrode of piezoelectric ceramic sheet by electroplating and vacuum coating method. The electrode of piezoelectric ceramic sheet is located on the plane of both ends in the thickness direction; The electric ceramic sheet is subjected to polarization treatment; laminated bonding: the various types of prepared piezoelectric ceramic sheets are laminated according to the principle of opposite polarization directions, and are bonded to the driving end by an adhesive according to the design requirements And power generation end, the curing temperature of the adhesive used should be much lower than the Curie temperature of the piezoelectric ceramic material used; transformer molding: the drive end, the insulation sheet and the power generation end are pressed in the vertical direction by the drive end, the insulation sheet, and the power generation end , Insulation sheet, drive end, insulation sheet, power generation end, ... are stacked in order, and the transformer is bonded by an adhesive;

Electrode connection: each piece of the drive end is connected in series or in parallel as an input terminal, and each piece of the power generation end is connected in parallel as an output terminal with different output characteristics; the process temperature of the external connection method should be 100 lower than the Curie temperature of the piezoelectric material ^e C or more.

15. The method for manufacturing a piezoelectric ceramic transformer with a composite structure according to claim 14, wherein the piezoelectric ceramic sheet has a cross section perpendicular to the axial direction, which may be a circle, a regular polygon, or a rectangle.

16. Production of a composite structure piezoelectric ceramic transformer according to claim 14 or 15 The method is characterized in that when multiple sets of outputs are required and the output requirements are different, the piezoelectric sheet at the power generating end is processed into different thicknesses or different materials are selected.

17. The method for manufacturing a piezoelectric ceramic transformer with a composite structure according to claim 14, characterized in that the adhesive is generally a modified epoxy, modified phenolic, modified urea-formaldehyde, polyimide, or acrylic adhesive. .

18. The method for manufacturing a piezoelectric ceramic transformer with a composite structure according to claim 14, further comprising the steps of connecting the outer surfaces of the first and last driving ends of the transformer with two insulating films, respectively.

19. A piezoelectric ceramic transformer with a composite structure, characterized in that it has no less than two driving terminals, one power generating terminal less than the number of driving terminals, and two times as many insulating sheets as the power generating terminals, wherein The components are stacked on top of each other in the vertical direction in the order of the drive end, the insulation sheet, the power generation end, the insulation sheet, the drive end, the insulation sheet, the power generation end, ... to form a multilayer ceramic composite piezoelectric ceramic transformer; Each drive end and power generation end are monolithic structures.

20. The piezoelectric ceramic transformer with a composite structure according to claim 19, wherein the outer surfaces of the first and last driving ends of the transformer are connected to two insulating films, respectively.

21. A manufacturing method of a composite monolithic piezoelectric ceramic transformer, characterized in that it includes the following steps:

Covering the internal electrode (b): After cutting the film, the upper electrode is printed with a palladium-silver internal electrode paste on a printing machine;

Laminated molding (c): the membranes printed with internal electrodes are oriented in a direction opposite to each other Superimposed to reach the number of layers required for the drive end and the power generation end respectively, and then subject the upper and lower sides of the press to uniform pressure on the sides and press it into the required body;-drying (d): the process ( c) The formed blank is placed in a drying cabinet at a temperature of 80 ^e C-120. (: Drying for 6-48 hours;

Debinding (e): Put the dried material in step (d) into a kiln for low temperature and slow temperature rise to vaporize the plasticizer. The low temperature is from 100 ^e C to 35 CTC. ;

(6) High temperature sintering (e): sintering the billet processed in step (5) in an industrial kiln, the material is ordinary pressure sintering, and the sintering temperature is 900 ^e C-1150. C, made of piezoelectric ceramic porcelain body;

Coated external electrode and polarization (g): After cooling the piezoelectric ceramic porcelain sintered in step (f) to room temperature, take it out for cleaning and cover the external electrode and place it at 120. C's silicone oil was polarized at an electric field intensity of 3000-4500 V / mm for 20 minutes, so that the electric domains in the porcelain body were aligned in the direction of the electric field;

Inspection and assembly (h): After the polarization in step (g), according to the design parameters required by the design, after passing the inspection, the assembly is performed in the vertical direction with the prepared insulation sheet in the following order:

First drive end, first insulation sheet, first power generation end, second insulation sheet, second drive end, third insulation sheet, second power generation end, fourth insulation sheet, third drive end ... … And so on to the nth drive end, the 2n-1 insulation sheet, the _η power generation end, the 2η insulation sheet, and the η + 1 drive end in turn, forming a composite structure piezoelectric ceramic transformer.

22. The manufacturing method of a composite monolithic piezoelectric ceramic transformer according to claim 21, wherein said step further comprises connecting the outer surfaces of the first and last driving ends of said transformer to two insulating films, respectively.

23. Production of a composite monolithic piezoelectric ceramic transformer according to claim 21 The method is characterized in that the driving end, the power generating end and the insulating sheet can be bonded, welded or sintered at a low temperature.

24. A method of manufacturing a composite monolithic piezoelectric ceramic transformer according to claim 21, wherein the natural number n is not greater than 10.

25. The method for manufacturing a composite monolithic piezoelectric ceramic transformer according to claim 21, characterized in that the formed billet is placed in a drying box and dried at a temperature of 10 o ^e c for 24 hours.

26. A method of manufacturing a composite monolithic piezoelectric ceramic transformer according to claim 21, characterized in that the blank is sintered in an industrial kiln, and the driving end and the power generating end are at loocrc and io80, respectively. c Fired into a monolithic piezoelectric ceramic porcelain body.

27. A low-temperature sintered composite perovskite-type electronic ceramic material for manufacturing a piezoelectric ceramic transformer according to claim 1, 10, 19, characterized in that: it contains strontium and niobium in a total weight of 60-99.7% Based on a composition of lead, magnesium, nickel ion zirconate titanate and sodium silicate which accounts for 0-10% of the total weight, adding 0.1-10% oxidation, 0.1-10% manganese dioxide and 0.1- 10% of cerium dioxide produces a low-temperature sintered composite perovskite electronic ceramic material. Its chemical formulation is:

_U% wt (ΡΟ _χ (Nb _{2 /} Mg _{i / 3} ) _y

0 ₃ ]

+ R% wt Na, Si0 ₃ + M% wt CdO + N wt Mn0 ₂ + P% wt Ce0 ₂

u = 60.0 -99.7 x = 0.00-0.05 y = 0.00-0.30

Z = 0.00-0.30 W = 0.10-0.35 R = 0.00-10.0

M = 0.10—10.0 N = 0.10-10.0 P = 0.10—10.0 where% wt represents weight percentage.

28. A method for manufacturing a low-temperature sintered composite perovskite electronic ceramic material, comprising the following steps: Ingredients (1 '): Based on the composition of 60%-99.7% lead zirconate titanate containing strontium, niobium, magnesium and nickel ions and 0-10% sodium silicate based on the total weight, After adding 0.1 to 10% of cadmium oxide, 0.1 to 10% of manganese dioxide and 0.1 to 10% of cerium oxide, the mixture is mixed uniformly;

Pre-firing (2 '): After batching according to the procedure (1'), it is placed in a heating furnace for pre-firing, and the pre-firing temperature gradually increases from low to 850. C-900. C, so that the ingredient composition completes the solid phase reaction;

Grinding (3 '): Pre-sintered billet according to step (2'), take out and grind it into powder; Forming ( ⁴ '): Milled powder according to step ( ³ '), according to required shape Processing and molding; Sintering (5 '): Put the formed blank into a heating furnace for sintering. The material is ordinary pressure sintering, and the sintering temperature is 950 ^e C-1050 ^e C. It is made into composite perovskite electronic ceramic material. ;

Polarization treatment (6 '): The sintered ceramic part is covered with an external electrode and polarized in a 120 ° C silicone oil at a field strength of 4 kV / mm for 20 minutes, so that the internal domains of the ceramic material are aligned in the direction of the electric field.

29. A power supply circuit using a piezoelectric ceramic transformer with a low transformation ratio as claimed in claim 1, 10, and 19, wherein an AC power source (1) is passed through a rectifier (2) and a DC conversion and voltage stabilization circuit ( 3) A DC working power supply for providing a square-wave pulse-width modulation generator (4) and a driver (5) for the half-bridge output circuit. The driver (5) provides MOSFETs for the half-bridge power amplifier (6, 7). The driving voltage is generated, and an excitation voltage acting on the piezoelectric ceramic (8) is added to the excitation electrode (801), and the alternating-current piezoelectric signal is output from the secondary-side induction electrode (802) of the piezoelectric ceramic (8), and is specially rectified The filter voltage stabilization circuit (16) obtains a DC output (17), which is characterized in that the square wave output from the half bridge is set to a sine wave and added to the piezoelectric ceramic excitation electrode (801). The inductance (9), capacitance (10) of the various vibration circuits and the third and fifth harmonic filter circuits composed of the inductance (11) and the capacitance (12); The compensation inductance coil (13) for reducing phase shift, reactive power and inrush current is combined with the excitation electrode (801) of the piezoelectric ceramic (8) ^ ^

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A ENDED SHEET ^ ARTICLE 19)

Declaration of amendments under Article 19

The amendment addresses the lack of unity between the original claims 1-9, 10-16, and 17-21, with a textual correction. None of the above-mentioned modifications exceed the scope of the originally filed description, drawings, and claims.