CN112072956A

CN112072956A - Multi-input piezoelectric vibration energy acquisition circuit

Info

Publication number: CN112072956A
Application number: CN202010834853.0A
Authority: CN
Inventors: 夏银水; 陈志栋
Original assignee: Ningbo University
Current assignee: Ningbo University
Priority date: 2020-08-19
Filing date: 2020-08-19
Publication date: 2020-12-11
Anticipated expiration: 2040-08-19
Also published as: CN112072956B

Abstract

The invention discloses a multi-input piezoelectric vibration energy acquisition circuit which is characterized by comprising a plurality of piezoelectric acquisition modules, an inductor, an energy storage capacitor and a load, wherein each piezoelectric acquisition module comprises a piezoelectric sheet, a first NPN tube, a first PNP tube, a second NPN tube, a third PNP tube, a third NPN tube, a fourth PNP tube, a first capacitor and a second capacitor; the piezoelectric energy collection circuit has the advantages that piezoelectric energy can be collected for a plurality of piezoelectric power supplies at the same time, and the parasitic capacitor in the piezoelectric sheet is charged through the LC resonance circuit, so that the voltage of the piezoelectric sheet in the next half period is improved, the output power is increased, a diode is not needed in the circuit, the loss of the diode is effectively removed, and the whole energy collection efficiency is improved.

Description

Multi-input piezoelectric vibration energy acquisition circuit

Technical Field

The invention relates to an energy acquisition circuit, in particular to a multi-input piezoelectric vibration energy acquisition circuit.

Background

Wireless sensor networks are composed of a number of spatially distributed autonomous sensor devices that can be used to monitor various physical and environmental conditions, however, powering these ubiquitous wireless sensor network nodes and making them completely self-sustaining remains a critical difficulty.

The vibration energy is one energy widely existing in the environment, and the vibration energy in the environment is collected to supply power to the wireless sensing network node with low power consumption; the collection of vibration energy mainly relies on the electric charge that produces when collecting the vibration of piezoelectric patches, and the piezoelectric energy collection circuit that is common at present mainly is designed to single piezoelectric patches to there often has the diode in the circuit, and there is energy loss when the diode is worked, can reduce energy collection efficiency.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a multi-input piezoelectric vibration energy collecting circuit which can simultaneously collect piezoelectric energy from a plurality of piezoelectric power supplies and has higher collecting efficiency.

The technical scheme adopted by the invention for solving the technical problems is as follows: a multi-input piezoelectric vibration energy collecting circuit comprises a plurality of piezoelectric collecting modules, an inductor, an energy storage capacitor and a load, wherein each piezoelectric collecting module comprises a piezoelectric sheet, a first NPN tube, a first PNP tube, a second NPN tube, a third PNP tube, a third NPN tube, a fourth PNP tube, a first capacitor and a second capacitor, one end of each piezoelectric sheet, a collector of the first NPN tube, a base of the first PNP tube, a collector of the third PNP tube, a base of the third NPN tube and one end of the second capacitor are connected, a base of the first NPN tube is connected with the collector of the first PNP tube, an emitter of the third NPN tube and one end of the first capacitor are connected, an emitter of the second PNP tube, an emitter of the fourth NPN tube and the other end of the second capacitor are connected, the other end of the piezoelectric sheet, the base of the second PNP tube, the base of the fourth NPN tube, the collector of the second NPN tube, the collector of the fourth PNP tube and the other end of the first capacitor are connected, the collector of the second PNP tube is connected with the base of the second NPN tube, the base of the third PNP tube is connected with the collector of the third NPN tube, the collector of the fourth NPN tube is connected with the base of the fourth PNP tube, the emitter of the first NPN tube, the emitter of the second NPN tube and one end of the inductor are connected, the other end of the inductor, one end of the energy storage capacitor and one end of the load are connected, and the emitter of the third PNP tube, the emitter of the fourth PNP tube, the other end of the energy storage capacitor and the other end of the load are all grounded.

Compared with the prior art, the piezoelectric energy collecting device has the advantages that piezoelectric energy can be collected for a plurality of piezoelectric power supplies at the same time, and parasitic capacitors in the piezoelectric sheets are charged through the LC resonance circuit, so that the voltage of the piezoelectric sheets in the next half period is improved, the output power is increased, diodes are not needed in a circuit, the loss of the diodes is effectively removed, and the integral energy collecting efficiency is improved; in the process that the piezoelectric sheet moves from the zero displacement point to the maximum displacement point, the parasitic capacitor inside the piezoelectric sheet is continuously charged, when the displacement of the piezoelectric sheet reaches the maximum value, the energy storage on the parasitic capacitor inside the piezoelectric sheet also reaches the maximum value, at the moment, the switch tube in the piezoelectric acquisition module is conducted, so that the inductor, the piezoelectric acquisition module and the energy storage capacitor, of which the displacement of the piezoelectric sheet reaches the maximum point, form an LC resonance circuit, then, part of energy stored on the parasitic capacitor of the piezoelectric sheet is transferred to the energy storage capacitor through LC resonance, and the other part of energy is reversely charged back to the parasitic capacitor inside the piezoelectric sheet, so that the voltage of the piezoelectric sheet in the next half period can reach a higher value; the whole circuit structure can be superposed, namely, the piezoelectric acquisition modules can be added or reduced according to the actual application scene so as to be suitable for different application scenes.

Drawings

FIG. 1 is a schematic diagram of the circuit structure of the present invention;

fig. 2 is a circuit structure diagram of the piezoelectric acquisition module of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

A multi-input piezoelectric vibration energy collecting circuit comprises a plurality of piezoelectric collecting modules, an inductor L, an energy storage capacitor Cr and a load RL, wherein each piezoelectric collecting module comprises a piezoelectric sheet PZT, a first NPN tube Q1, a first PNP tube Q2, a second PNP tube Q3, a second NPN tube Q4, a third PNP tube Q5, a third NPN tube Q6, a fourth NPN tube Q7, a fourth PNP tube 8, a first capacitor C1 and a second capacitor C2, one end of each piezoelectric sheet PZT, a collector of the first NPN tube Q1, a base of the first PNP tube Q2, a collector of the third PNP tube Q5, a base of the third NPN tube Q6 and one end of the second capacitor C2 are connected, a base of the first NPN tube Q1 is connected with a collector of the first PNP tube Q2, an emitter of the first PNP tube Q2, an emitter of the third NPN tube Q24 and one end of the first capacitor C2 are connected with an emitter of the first PNP tube Q599, and an emitter of the second PNP tube Q599, and an emitter of the fourth PNP tube Q599 and an emitter of the other end of the piezoelectric sheet PZT tube Q59, The base of the second PNP tube Q3, the base of the fourth NPN tube Q7, the collector of the second NPN tube Q4, the collector of the fourth PNP tube Q8, and the other end of the first capacitor C1 are connected, the collector of the second PNP tube Q3 is connected to the base of the second NPN tube Q4, the base of the third PNP tube Q5 is connected to the collector of the third NPN tube Q6, the collector of the fourth NPN tube Q7 is connected to the base of the fourth PNP tube Q8, the emitter of the first NPN tube Q1, the emitter of the second NPN tube Q4, and one end of the inductor L are connected, the other end of the inductor L, one end of the storage capacitor Cr, and one end of the load RL are connected, and the emitter of the third PNP tube Q5, the emitter of the fourth PNP tube Q8, the other end of the storage capacitor Cr, and the other end of the load RL are connected.

The working principle of the above embodiment is as follows: taking any one piezoelectric energy acquisition module as an example, at the beginning of a positive half cycle, an initial voltage exists on the piezoelectric sheet PZT, that is, the voltage of one end of the piezoelectric sheet PZT is higher than that of the other end of the piezoelectric sheet PZT, and the initial voltage is the electric charge left on the piezoelectric sheet PZT after the LC resonance of the last negative half cycle is finished; then, as the piezoelectric patches PZT vibrate slowly, the voltage difference across the piezoelectric patches PZT increases gradually, and the potential difference across the first capacitor C1 and the second capacitor C2 also increases continuously until the voltage difference across the piezoelectric patches PZT reaches a peak value, and then the voltage difference across the piezoelectric patches PZT starts to decrease, but because the charges accumulated on the first capacitor C1 and the second capacitor C2 are not released by the loop, the voltages across the first capacitor C1 and the second capacitor C2 remain unchanged until the voltage across the first capacitor C1 is greater than the sum of the threshold voltages of the first PNP tube Q2 and the third NPN tube Q6, and the voltage across the second capacitor C2 is greater than the sum of the threshold voltages of the second PNP tube Q3 and the fourth NPN tube Q7, at this time, the first PNP tube Q2 and the fourth NPN tube Q7 are turned on, so that the first NPN tube Q1 and the fourth NPN tube Q8 are turned on; at the moment, the inductor L, the piezoelectric plate PZT and the energy storage capacitor Cr form an LC resonance loop, then one part of energy stored in the parasitic capacitor of the piezoelectric plate PZT is transferred to the energy storage capacitor Cr through LC resonance, the other part of energy is transferred to the parasitic capacitor returning to the piezoelectric plate PZT through LC resonance, the parasitic capacitor of the piezoelectric plate PZT has voltage, and the voltage of the other end of the piezoelectric plate PZT is higher than that of one end;

in the negative half period, the voltage at the other end of the piezoelectric sheet PZT is higher than that at one end, the voltage difference on the piezoelectric sheet PZT gradually increases along with the slow vibration of the piezoelectric sheet PZT, the potential difference between the two ends of the first capacitor C1 and the first capacitor C2 also continuously increases until the voltage difference between the two ends of the piezoelectric sheet PZT reaches the peak value, then the voltage difference between the two ends of the piezoelectric sheet PZT starts to decrease, but because the charges accumulated on the first capacitor C1 and the second capacitor C2 are not released back, the voltage difference between the first capacitor C1 and the second capacitor C2 remains unchanged, therefore, the voltage across the first capacitor C1 and the second capacitor C2 remains unchanged until the voltage across the first capacitor C1 is greater than the sum of the threshold voltages of the first PNP transistor Q2 and the third NPN transistor Q6, the voltage across the second capacitor C2 is greater than the sum of the threshold voltages of the second PNP transistor Q3 and the fourth NPN transistor Q7, at this time, the second PNP transistor Q3 and the third NPN transistor Q6 are turned on, so that the second NPN transistor Q4 and the third PNP transistor Q5 are turned on; at this time, the inductor L, the piezoelectric patches PZT and the energy storage capacitor Cr form an LC resonant circuit, then a part of the energy stored in the parasitic capacitors of the piezoelectric patches PZT is transferred to the energy storage capacitor Cr through LC resonance, and another part of the energy is transferred to the parasitic capacitors returned to the piezoelectric patches PZT through LC resonance, at this time, the parasitic capacitors of the piezoelectric patches PZT have voltage, and one end of the piezoelectric patches PZT has voltage higher than the other end of the piezoelectric patches PZT.

Claims

1. A multi-input piezoelectric vibration energy collecting circuit is characterized by comprising a plurality of piezoelectric collecting modules, an inductor, an energy storage capacitor and a load, wherein each piezoelectric collecting module comprises a piezoelectric sheet, a first NPN tube, a first PNP tube, a second NPN tube, a third PNP tube, a third NPN tube, a fourth PNP tube, a first capacitor and a second capacitor, one end of each piezoelectric sheet, a collector of the first NPN tube, a base of the first PNP tube, a collector of the third PNP tube, a base of the third NPN tube and one end of the second capacitor are connected, a base of the first NPN tube is connected with a collector of the first PNP tube, an emitter of the third NPN tube and one end of the first capacitor are connected, an emitter of the second PNP tube, an emitter of the fourth NPN tube and the other end of the second capacitor are connected, the other end of the piezoelectric sheet, the base of the second PNP tube, the base of the fourth NPN tube, the collector of the second NPN tube, the collector of the fourth PNP tube and the other end of the first capacitor are connected, the collector of the second PNP tube is connected with the base of the second NPN tube, the base of the third PNP tube is connected with the collector of the third NPN tube, the collector of the fourth NPN tube is connected with the base of the fourth PNP tube, the emitter of the first NPN tube, the emitter of the second NPN tube and one end of the inductor are connected, the other end of the inductor, one end of the energy storage capacitor and one end of the load are connected, and the emitter of the third PNP tube, the emitter of the fourth PNP tube, the other end of the energy storage capacitor and the other end of the load are connected.