CN112072953B - Extensible multi-source energy capture interface circuit - Google Patents

Abstract

The invention discloses a scalable multi-source energy capture interface circuit which is characterized by comprising a plurality of piezoelectric energy acquisition modules, a first inductor, a second inductor, a first diode, a second diode, an energy storage capacitor and a load resistor, wherein each piezoelectric energy acquisition module comprises a piezoelectric transducer, a first capacitor, a first NPN (negative-positive-negative) tube, a first PNP (positive-negative) tube, a second PNP tube and a second NPN tube; the advantage is that overall circuit structure is simpler to can gather the interchange type energy that piezoelectric energy represents simultaneously through simple increase repetition module, increase whole collection efficiency, can also increase or reduce corresponding module according to the application scene of reality, in order to be suitable for different application scenes.

Description

Extensible multi-source energy capture interface circuit

Technical Field

The invention relates to an energy acquisition circuit, in particular to a scalable multi-source energy capture interface circuit.

Background

In the last decade, the internet of things has become a research hotspot, and meanwhile, wireless sensor network nodes are widely applied in the fields of environmental monitoring, wearable equipment, consumer electronics, human health monitoring systems and the like. However, the conventional battery-powered approach of wireless sensor network nodes is a non-negligible obstacle in a wide range of applications. Therefore, harvesting environmental energy is considered to be one of the effective methods to overcome this challenge, with light, heat, wind and vibration energy being the most common environmental energy sources; among them, piezoelectric vibration energy has attracted great interest as a means of collecting environmental kinetic energy to drive wireless sensor network nodes due to its compatibility and relatively high energy density.

At present, a common piezoelectric energy collecting circuit is mainly designed for a single cantilever beam structure, however, one vibration source can often be provided with a plurality of piezoelectric transducers so as to generally obtain more energy, the problem of shared use of an inductor is mainly solved by adopting a time-sharing multiplexing method in the existing circuit for simultaneously collecting the vibration energy by adopting a plurality of piezoelectric transducers, and the overall piezoelectric collecting efficiency is not improved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a scalable multi-source energy capture interface circuit which has a simpler overall circuit structure and higher energy collection efficiency.

The technical scheme adopted by the invention for solving the technical problems is as follows: an expandable multi-source energy capture interface circuit comprises a plurality of piezoelectric energy acquisition modules, a first inductor, a second inductor, a first diode, a second diode, an energy storage capacitor and a load resistor, wherein each piezoelectric energy acquisition module comprises a piezoelectric transducer, a first capacitor, a first NPN tube, a first PNP tube, a second PNP tube and a second NPN tube, one end of the piezoelectric transducer, the base of the first NPN tube, the base of the first PNP tube, the collector of the second PNP tube and the collector of the second NPN tube are connected, the emitter of the first NPN tube, the emitter of the first PNP tube and one end of the first capacitor are connected, the collector of the first NPN tube is connected with the base of the second PNP tube, the collector of the first PNP tube is connected with the base of the second NPN tube, and the emitter of the second NPN tube is connected with one end of the first inductor, the other end of the first inductor is connected with the anode of the first diode, the emitter of the second PNP tube, one end of the second inductor and the anode of the second diode are connected, the cathode of the first diode, the cathode of the second diode, one end of the energy storage capacitor and one end of the load resistor are connected, and the other end of the piezoelectric transducer, the other end of the first capacitor, the other end of the second inductor, the other end of the energy storage capacitor and the other end of the load resistor are all grounded.

Compared with the prior art, the invention has the advantages that the whole circuit structure is simpler, the alternating current type energy represented by piezoelectric energy can be simultaneously collected by simply adding the repeated modules, the whole collection efficiency is improved, and the corresponding modules can be added or reduced according to the actual application scene so as to be suitable for different application scenes; firstly, in a positive half period, in the process that the piezoelectric transducer moves from a zero displacement point to a maximum displacement point, a parasitic capacitor in the piezoelectric transducer is continuously charged, when the displacement of the piezoelectric transducer reaches the maximum, the stored energy on the parasitic capacitor in the piezoelectric transducer also reaches the maximum, at the moment, a second NPN tube in the piezoelectric energy acquisition module is conducted, so that the piezoelectric transducer and the stored energy capacitor, of which the first inductor and the piezoelectric transducer reach the maximum displacement point, form an LC resonance circuit, and after 1/2 LC resonance periods, part of the energy in the piezoelectric energy acquisition module in the LC resonance circuit is transferred to the stored energy capacitor, and the other part of the energy returns to the piezoelectric transducer, so that the voltage of the piezoelectric transducer is reversed, and the efficiency of a negative half period can be improved; in a negative half period, in the process that the piezoelectric transducer moves from a zero displacement point to the most other direction, the parasitic capacitor in the piezoelectric transducer is continuously charged with negative charges on the basis of reverse voltage, the voltage at the moment is negative, when the displacement of the piezoelectric transducer reaches the maximum negative displacement, the stored energy on the parasitic capacitor in the piezoelectric transducer also reaches the maximum negative voltage value, the second PNP tube in the piezoelectric energy acquisition module is conducted, so that the second inductor and the piezoelectric transducer form an LC resonance circuit, through 1/4 LC resonance periods, the energy in the piezoelectric transducer in the LC resonance circuit is transferred to the second inductor, the passage is immediately turned off, the second inductor and the stored energy capacitor form a circuit, and the second inductor transfers the piezoelectric energy to the stored energy capacitor; the five processes are completely independent, so that the energy collection efficiency is effectively improved, and the dependence on the load is less.

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 energy harvesting module according to the present invention.

Detailed Description

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

A scalable multi-source energy capture interface circuit comprises a plurality of piezoelectric energy collection modules, a first inductor L1, a second inductor L2, a first diode D1, a second diode D2, an energy storage capacitor Cr and a load resistor RL, wherein each piezoelectric energy collection module comprises a piezoelectric transducer PZT, a first capacitor C1, a first NPN tube Q1, a first PNP tube Q2, a second PNP tube Q3 and a second NPN tube Q4, one end of each piezoelectric transducer PZT, a base of the first NPN tube Q1, a base of the first PNP tube Q2, a collector of the second NPN tube Q3 and a collector of the second NPN tube Q4 are connected, an emitter of the first NPN tube Q1, an emitter of the first NPN tube Q2 and one end of the first capacitor C1 are connected, a collector of the first NPN tube Q1 is connected with the base of the second PNP tube Q3, a collector of the first PNP tube Q is connected with a base of the second PNP tube Q4, and one end of the second NPN tube Q4 is connected with an emitter of the first inductor L1, the other end of the first inductor L1 is connected with the positive electrode of the first diode D1, the emitter of the second PNP tube Q3, one end of the second inductor L2 and the positive electrode of the second diode D2 are connected, the cathode of the first diode D1, the cathode of the second diode D2, one end of the energy storage capacitor Cr and one end of the load resistor RL are connected, and the other end of the piezoelectric transducer PZT, the other end of the first capacitor C1, the other end of the second inductor L2, the other end of the energy storage capacitor Cr and the other end of the load resistor RL are all grounded.

The working principle of the above embodiment is as follows: taking any piezoelectric energy acquisition module as an example, in a positive half period, namely when the voltage of the positive end of the piezoelectric transducer PZT is higher than the voltage of the negative end, along with the continuous increase of the displacement of the piezoelectric transducer PZT, the voltage at two ends of the piezoelectric transducer PZT is also continuously increased; meanwhile, due to the existence of an intrinsic diode of the first NPN tube Q1, the voltage at two ends of the first capacitor C1 continuously follows the voltage at two ends of the piezoelectric transducer PZT, until the voltage at two ends of the piezoelectric transducer PZT reaches a positive peak value, the voltage at two ends of the piezoelectric transducer PZT is gradually reduced due to the reverse charging of a current source, and the first capacitor C1 does not have a discharging loop, so that the voltage at the moment is still kept at a constant value, and the maximum voltage stored by the first capacitor C1 is the voltage of the piezoelectric transducer PZT minus the voltage drop of the intrinsic diode of the first NPN tube Q1; until the difference between the voltage at the two ends of the piezoelectric transducer PZT and the voltage at the two ends of the first capacitor C1 is greater than the sum of the threshold voltage of the first PNP transistor Q2 and the conduction voltage drop of the diode in the first NPN transistor Q1, the first PNP transistor Q2 is conducted, so that the second NPN transistor Q4 is conducted, at this time, the internal parasitic capacitor of the first piezoelectric transducer PZT, the first inductor L1, the first diode D1 and the energy storage capacitor Cr form an LC resonance loop, and the loop passes through 1/2 LC resonance cycles, so that a part of the charges accumulated on the internal parasitic capacitor of the piezoelectric transducer PZT can be transferred to the energy storage capacitor Cr, and the rest part of the charges is used for reversing the voltage of the internal parasitic capacitor of the piezoelectric transducer PZT to improve the capture energy of the negative half cycle; when the current on the first inductor L1 becomes 0, the resonant tank can be naturally closed at 1/2 resonant cycles due to the presence of the first diode D1;

in a negative half period, namely when the voltage at the other end of the piezoelectric transducer PZT is higher than the voltage at one end, along with the increase of the displacement of the piezoelectric transducer PZT in a continuous reverse direction, the voltage difference at the two ends of the piezoelectric transducer PZT is also increased continuously; meanwhile, due to the existence of an intrinsic diode of the first PNP tube Q2, the voltage at two ends of the first capacitor C1 continuously follows the voltage at two ends of the piezoelectric transducer PZT until the voltage at two ends of the piezoelectric transducer PZT reaches a negative peak value, at this time, the voltage difference at two ends of the piezoelectric transducer PZT is gradually reduced due to the reverse charging of the current source, and the first capacitor C1 has no discharging loop, so the voltage at this time is still kept at a constant value, the maximum voltage stored in the first capacitor C1 is the voltage of the piezoelectric transducer PZT plus the voltage drop of the intrinsic diode of the first PNP tube Q2 until the voltage difference between the piezoelectric transducer PZT and the first capacitor C1 is greater than the sum of the threshold voltage of the first NPN tube Q1 and the conduction voltage drop of the intrinsic diode of the first PNP tube Q2, and at this time, the first NPN tube Q1 is turned on, thereby causing the conduction of the second PNP tube Q3; at this time, the capacitor Cp of the first piezoelectric transducer PZT and the second inductor L2 form an LC resonant loop, and the loop can transfer the charges accumulated on the parasitic capacitor inside the piezoelectric transducer PZT to the second inductor L2 through 1/4 LC resonant cycles, where the charges include not only the charges generated by the current source in the negative half cycle but also the reversed part of the charges in the positive half cycle; when the current of the second inductor L2 reaches the maximum value, the charge on the first capacitor C1 is released completely, so that the first NPN transistor Q1 is disconnected, that is, the LC resonant circuit is disconnected, then the inductor L2, the second diode D2 and the energy storage capacitor Cr form a circuit, and the energy accumulated in the second inductor L2 flows to the energy storage capacitor Cr through the diode D2, thereby realizing energy extraction in the negative half cycle.

Claims (1)

1. An expandable multi-source energy capture interface circuit is characterized by comprising a plurality of piezoelectric energy acquisition modules, a first inductor, a second inductor, a first diode, a second diode, an energy storage capacitor and a load resistor, wherein each piezoelectric energy acquisition module comprises a piezoelectric transducer, a first capacitor, a first NPN tube, a first PNP tube, a second PNP tube and a second NPN tube, one end of the piezoelectric transducer, the base of the first NPN tube, the base of the first PNP tube, the collector of the second PNP tube and the collector of the second NPN tube are connected, the emitter of the first NPN tube, the emitter of the first PNP tube and one end of the first capacitor are connected, the collector of the first NPN tube is connected with the base of the second PNP tube, the collector of the first PNP tube is connected with the base of the second NPN tube, the emitter of the second NPN tube is connected with one end of the first inductor, the other end of the first inductor is connected with the anode of the first diode, the emitter of the second PNP tube, one end of the second inductor and the anode of the second diode are connected, the cathode of the first diode, the cathode of the second diode, one end of the energy storage capacitor and one end of the load resistor are connected, and the other end of the piezoelectric transducer, the other end of the first capacitor, the other end of the second inductor, the other end of the energy storage capacitor and the other end of the load resistor are all grounded.

Images