RU2038656C1 - Secondary power supply source - Google Patents

Abstract

FIELD: radio engineering. SUBSTANCE: secondary power supply source has unit 1 generating electric signal of conversion frequency, piezoelectric disc transformer 2 and rectifier 3 connected in series. Electrodes of input section 5 of transformer are applied in center of both flat surfaces of piezodisc 4 in the form of circle with radius equal to 0.34 radius of disc and electrodes of output section 6 are applied on same surfaces of disc 4 in region limited by radii equal to 0.5 and 0.97 radius of disc. Disc 4 of piezotransformer 2 is anchored mechanically in central point where electric connection of generating unit 1 and electrodes of input section 5 is accomplished and in points away from center by 0.7 radius of disc where electric connection of electrodes of section 6 and rectifier 4 is carried out. EFFECT: enhanced operational stability, facilitated manufacture. 4 dwg

Description

 The invention relates to electronics and can be used, in particular, in the production of secondary power supplies for radio devices, video and audio recorders, computers, etc.

 Closest to the invention is a secondary power source containing an electric signal generating unit with a conversion frequency, a piezoelectric disk transformer and a rectifier. An electrical signal coming from the output of the generation unit to the input of the piezotransformer excites mechanical vibrations in it. This leads to the appearance of an electrical variable signal in the output section of the transformer, which can be converted into a constant output voltage using a rectifier.

 The disadvantages of this secondary power source are low efficiency and, therefore, the inability to provide high power transmission.

 The objective of the invention is the creation of a secondary power source, which allows to increase the efficiency and ensure maximum transmitted energy with a fixed size piezotransformer.

 For this, in a secondary power source containing a series-connected unit for generating an electrical signal with a conversion frequency, a piezoelectric disk transformer with input and output sections of the electrodes and a rectifier, the input section of the piezoelectric transformer is formed by electrodes deposited in the center of both flat surfaces of the piezoelectric disk in the form of a circle with a radius equal to 0.34 of the radius of the disk circle, and the output section by electrodes deposited on both flat surfaces of the piezodisc in the area bounded by circles with radii equal to 0.5 and 0.97 of the radius of the disk, the piezoelectric disk is mechanically fixed at the center point, providing it also with an electrical connection between the generation unit and the input section of the transformer and at points 0.7 from the center point the radius of the disk, providing them with an electrical connection to the output section of the transformer and rectifier.

In FIG. 1 shows a diagram of a secondary power source; figure 2 equivalent electromechanical circuit of a piezotransformer; figure 3 the dependence of the coefficient K ₁ electromechanical connection of the transformer inlet from the size of the input section; figure 4 the dependence of the coefficient K ₂ electromechanical connection of the transformer in the output from the location of the output section.

 The secondary power source consists of a series-connected unit 1 generating an electrical signal, a piezoelectric disk transformer 2 and a rectifier 3.

 The piezoelectric transformer 2 is made in the form of a piezoelectric disk 4, on which are applied the electrodes of the input and output sections 5 and 6, respectively.

 Contacts 7 and 8, intended for mechanical fastening of the electric piezo disk 4, are also electrical contacts. Using the central contact 7, an electrical connection is made between the generation unit 1 and the electrodes of the input section 5 of the piezotransformer 2. The electrodes of the output section 6 of the piezotransformer 2 are electrically connected to the input of the rectifier 3 using peripheral contacts 8.

 The electrodes of the input section 5 of the disk piezotransformer 2 are deposited in the center of both planes of the piezoelectric disk 4 in an area bounded by a circle with a radius of 0.34 radius R of the disk, and the electrodes of the output section 6 are deposited on the same surfaces of the disk in an area bounded by circles with radii of 0.5 and 0.97 of the radius R of the disk.

 The peripheral contacts 8 ensure the fastening of the piezoelectric disk 4 at points spaced 0.7 from its center by its radius (R).

 The secondary power source operates as follows.

 The electric signal coming from the output of the electric signal generating unit 1 to the electrodes of the input section 5 of the piezotransformer 2 excites mechanical vibrations in it, which leads to the appearance of an electric alternating signal at the electrodes and the output section 6 of the piezotransformer 2, which is converted by a rectifier 3 into a constant electric voltage .

 The choice of the mounting points of the piezotransformer transformer disk 2 using contacts 7 and 8, as well as the size and arrangement of the electrodes of the input and output sections 5 and 6, provide maximum values of efficiency and transmitted power at fixed values of the piezoceramic disk.

r

, (1) где А константа, зависящая от размеров диска и величины возбуждающего напряжения;
I₁ функция Бесселя;
ω_р частота резонанса;
С скорость звука;
r текущая координата по радиусу.The distribution of vibrational velocities v in the body of the piezoelectric disk for the second vibrational mode can be represented as
v A · I

r

, (1) where A is a constant depending on the size of the disk and the magnitude of the exciting voltage;
I ₁ Bessel function;
ω _p resonance frequency;
With the speed of sound;
r current coordinate along the radius.

5,39, а функция Бесселя I(x) проходит через нуль в точках Х 0, Х 3,75 и т.д.It is known that for the second fashion

5.39, and the Bessel function I (x) passes through zero at points X 0, X 3.75, etc.

0,7R.Vibration velocity vanishes at r 0 and r R

0.7R.

 Therefore, the piezoelectric disk excited at the second harmonic does not oscillate at points with coordinates r 0 and r 0.7 R. Therefore, mechanical contact at these points does not lead to the removal of mechanical vibrations from the disk, i.e. There is no “parasitic" energy removal in this design.

For the equivalent electromechanical circuit of the piezotransformer shown in FIG. 2, the following designations are adopted: C ₀₁ and C _{02 the} electrical capacitance of the input and output sections, respectively, in the absence of mechanical vibrations of the disk; A ₁ and A _{2 are} ideal electromechanical transformers with appropriate transformation ratios; With ₁ , L ₁ and R ₁ mechanical flexibility, mass and resistance to internal friction of the disk, respectively; R ₁ load resistance.

и K $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$

.The coefficients of the electromechanical coupling of the transformer at the input and output, respectively, can be represented in the form
K $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$

and K $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$

.

и K₁ ˙ K₂ max.Analysis of the scheme shown in figure 2 shows that the maximum transmitted energy and efficiency are achieved under the condition
R

and K ₁ ˙ K ₂ max.

 The solution of the electromechanical problem for a piezoelectric disk oscillating in the second mode with different regions of the electrodes is shown in Figs. 3 and 4. The experimental values (x) are also shown here.

For the dependence of K ₂ shown in FIG. 4 on the location of the output section, the variable coordinate is the internal (smaller) radius of the output section with a fixed external radius equal to r / R 0.97. Exact calculations show that K ₁ reaches a maximum of r 0.34 R, and K ₂ when the electrode is located in the region of r ₁ 0.5 R and r ₂ 0.97 R.

 The use of the invention provides the creation of compact and economical power sources for various electronic equipment, in particular for video recorders.

Claims (1)

 A SECONDARY POWER SUPPLY comprising a series-connected unit for generating an electrical signal with a conversion frequency, a piezoelectric disk transformer with input and output sections of the electrodes and a rectifier, characterized in that the input section of the piezoelectric transformer is formed by electrodes deposited in the center of both flat surfaces of the piezoelectric disk in the form of a circle of radius equal to 0.34 of the radius of the disk circle, and the output section by electrodes deposited on both flat surfaces of the piezoelectric of the electric disk in the region bounded by circles with radii equal to 0.5 and 0.97 of the radius of the disk, the piezoelectric disk is mechanically fixed at the center point, providing it also with an electrical connection between the generation unit and the input section of the transformer and at points 0 from the center point , 7 of the radius of the disk, providing them with an electrical connection to the output section of the transformer and rectifier.

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