CN112072956B

CN112072956B - Multi-input piezoelectric vibration energy acquisition circuit

Info

Publication number: CN112072956B
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: 2023-06-06
Anticipated expiration: 2040-08-19
Also published as: CN112072956A

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 power collection circuit has the advantages that piezoelectric power can be collected for a plurality of piezoelectric power simultaneously, parasitic capacitance inside the piezoelectric sheet is charged through the LC resonant 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 diode loss is effectively removed, and the overall 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 made up of a number of spatially distributed autonomous sensor devices that can be used to monitor different physical and environmental conditions, however, it remains a critical difficulty to power these ubiquitous wireless sensor network nodes and to fully self-maintain them.

Vibration energy is an energy source widely existing in the environment, and the vibration energy in the environment is collected to supply power for the wireless sensor network node with low power consumption; the collection of vibration energy mainly relies on the charge that produces when collecting the vibration of piezoelectric plate, and current common piezoelectric energy collection circuit mainly is to single piezoelectric plate design to often there is the diode in the circuit, and there is energy loss when the diode work, can reduce energy collection efficiency.

Disclosure of Invention

The invention aims to solve the technical problem of providing a multi-input piezoelectric vibration energy acquisition circuit capable of simultaneously acquiring piezoelectric energy from a plurality of piezoelectric energy, and the acquisition efficiency is higher.

The technical scheme adopted for solving the technical problems is as follows: the multi-input piezoelectric vibration energy acquisition circuit comprises 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, one end of each piezoelectric sheet, a collector of each first NPN tube, a base of each first PNP tube, a collector of each third PNP tube, a base of each third NPN tube and one end of each second capacitor are connected, a base of each first NPN tube is connected with a collector of each first PNP tube, an emitter of each first NPN tube and one end of each first capacitor are connected, an emitter of each second PNP tube, each fourth NPN tube and the other end of each 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, 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 grounded.

Compared with the prior art, the piezoelectric device has the advantages that piezoelectric energy can be collected for a plurality of piezoelectric power sources at the same time, and parasitic capacitance in the piezoelectric sheet is charged through the LC resonant 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 diode loss is effectively removed, and the whole energy collection efficiency is improved; in the process that the piezoelectric sheet moves from a zero displacement point to a maximum displacement point, parasitic capacitance in the piezoelectric sheet is continuously charged, when the displacement of the piezoelectric sheet reaches the maximum, the energy storage on the parasitic capacitance in the piezoelectric sheet also reaches the maximum, at the moment, a switching tube in the piezoelectric acquisition module is conducted, so that an LC resonant circuit is formed by the inductance, the piezoelectric acquisition module and the energy storage capacitor of which the displacement of the piezoelectric sheet reaches the maximum point, then part of energy stored in the parasitic capacitance of the piezoelectric sheet can be transferred to the energy storage capacitor through LC resonance, and the other part of energy is reversely charged back to the parasitic capacitance in the piezoelectric sheet, so that the voltage of the piezoelectric sheet in the next half period can be higher; the whole circuit structure can be overlapped, namely the piezoelectric acquisition module can be increased or decreased according to the actual application scene, so that the piezoelectric acquisition module is suitable for different application scenes.

Drawings

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

fig. 2 is a circuit configuration diagram of a piezoelectric acquisition module according to the present invention.

Detailed Description

The invention is described in further detail below with reference to the embodiments of the drawings.

The multi-input piezoelectric vibration energy acquisition circuit comprises a plurality of piezoelectric acquisition modules, an inductor L, an energy storage capacitor Cr and a load RL, wherein each piezoelectric acquisition module comprises a piezoelectric plate 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 Q8, a first capacitor C1 and a second capacitor C2, one end of the piezoelectric plate 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, the base of the first NPN tube Q1 is connected with the collector of the first PNP tube Q2, the emitter of the third NPN tube Q6 and one end of the first capacitor C1 are connected, the emitter of the second PNP transistor Q3, the emitter of the fourth NPN transistor Q7 and the other end of the second capacitor C2 are connected, the other end of the piezoelectric plate PZT, the base of the second PNP transistor Q3, the base of the fourth NPN transistor Q7, the collector of the second NPN transistor Q4, the collector of the fourth PNP transistor Q8 and the other end of the first capacitor C1 are connected, the collector of the second PNP transistor Q3 is connected to the base of the second NPN transistor Q4, the base of the third PNP transistor Q5 is connected to the collector of the third NPN transistor Q6, the collector of the fourth NPN transistor Q7 is connected to the base of the fourth PNP transistor Q8, the emitter of the first NPN transistor Q1, the emitter of the second NPN transistor Q4 and one end of the inductor L are connected, and the other end of the inductor L, one end of the energy 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 piezoelectric energy collection module as an example, an initial voltage exists on the piezoelectric plate PZT at the beginning of a positive half period, namely, one end voltage of the piezoelectric plate PZT is higher than the other end voltage, and the initial voltage is the charge left on the piezoelectric plate PZT after the LC resonance of the previous negative half period is finished; then, as the piezoelectric plate PZT slowly vibrates, the voltage difference across the piezoelectric plate PZT gradually increases, until the voltage difference across the piezoelectric plate PZT reaches a peak value, and then the voltage difference across the piezoelectric plate PZT starts to decrease, but since the charges accumulated on the first capacitor C1 and the second capacitor C2 are not released in a 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 transistor Q2 and the third NPN transistor Q6, and 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 which time the first PNP transistor Q2 and the fourth NPN transistor Q7 are turned on, thereby causing the first PNP transistor Q1 and the fourth PNP transistor Q8 to be turned on; at this time, the inductance L, the piezoelectric plate PZT, and the energy storage capacitor Cr will form an LC resonant circuit, then a part of the energy stored in the parasitic capacitance of the piezoelectric plate PZT will be transferred to the energy storage capacitor Cr through LC resonance, and another part will be transferred to the parasitic capacitance returned to the piezoelectric plate PZT through LC resonance, at this time, the parasitic capacitance of the piezoelectric plate PZT will have a voltage, and the voltage at the other end of the piezoelectric plate PZT is higher than the voltage at one end;

in the negative half period, the voltage at the other end of the piezoelectric plate PZT is higher than the voltage at one end, as the piezoelectric plate PZT slowly vibrates, the voltage difference at the two ends of the piezoelectric plate PZT is increased, the potential difference at the two ends of the first capacitor C1 and the second capacitor C2 is also increased continuously until the voltage difference at the two ends of the piezoelectric plate PZT reaches a peak value, and then the voltage difference at the two ends of the piezoelectric plate PZT begins to decrease, but as the electric charge accumulated on the first capacitor C1 and the second capacitor C2 is not released in a loop, the voltage difference between the first capacitor C1 and the second capacitor C2 is kept unchanged, the voltage at the two ends of the first capacitor C1 and the second capacitor C2 is kept unchanged until the voltage at the two ends of the first capacitor C1 is larger than the sum of the threshold voltages of the first PNP tube Q2 and the third NPN tube Q6, and the voltage at the two ends of the second capacitor C2 is larger than the sum of the threshold voltages of the second PNP tube Q3 and the fourth NPN tube Q7, and at the second PNP tube Q3 and the third NPN tube Q5 are conducted at the moment; at this time, the inductance L, the piezoelectric plate PZT, and the energy storage capacitor Cr will form an LC resonant circuit, and then a part of the energy stored in the parasitic capacitance of the piezoelectric plate PZT will be transferred to the energy storage capacitor Cr through LC resonance, and another part will be transferred to the parasitic capacitance returned to the piezoelectric plate PZT through LC resonance, at this time, the parasitic capacitance of the piezoelectric plate PZT will have a voltage, and one end voltage of the piezoelectric plate PZT is higher than the other end voltage.

Claims

1. The multi-input piezoelectric vibration energy acquisition circuit 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, one end of each piezoelectric sheet, a collector electrode of each first NPN tube, a base electrode of each first PNP tube, a collector electrode of each third PNP tube, a base electrode of each third NPN tube and one end of each second capacitor are connected, a base electrode of each first NPN tube is connected with a collector electrode of each first PNP tube, an emitter electrode of each third NPN tube and one end of each first capacitor are connected, the emitter of the second PNP tube, the emitter of the fourth PNP 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 PNP tube, the collector of the second PNP 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, the emitter of the third PNP tube, the emitter of the fourth PNP tube are connected, the other end of the energy storage capacitor is connected with the other end of the load.