CN102684552B - Multiple-vibrator series-connection piezoelectric energy harvester - Google Patents

Abstract

The invention relates to a multi-vibrator series piezoelectric energy harvester, which belongs to the technical field of new energy and power generation. The housing is installed on the base by screws, and 1-50 piezoelectric transducers are placed in series in the housing; the piezoelectric transducer is composed of two piezoelectric vibrators riveted on the skeleton by rivets; the piezoelectric vibrators are made of metal The substrate and the piezoelectric wafer are bonded; the piezoelectric transducer is clamped with the deck, two adjacent piezoelectric transducers are clamped through the bayonet pin, and the piezoelectric transducer is connected with the claw at one end of the pin shaft. The other end of the pin shaft protrudes out of the shell and is equipped with a mass block; the pin shaft is covered with a first spring and a second spring in turn from bottom to top, and the first spring is pressed on the replacement by the shoulder of the pin shaft. On the transducer casing, the second spring is pressed on the transducer casing through a mass block; the circuit board is installed on the side wall of the transducer casing through screws. The advantage is that multiple piezoelectric vibrators are used in series and are limited by two springs, which can realize low-frequency, high-intensity, and high-power vibration energy recovery.

Description

A multi-oscillator series piezoelectric energy harvester

technical field

The invention belongs to the technical field of new energy and power generation, and specifically relates to a multi-vibrator series piezoelectric energy harvester for low-frequency, high-intensity vibration energy recovery.

Background technique

The research on micro-sized piezoelectric energy harvesters for environmental vibration energy recovery has become a new hot spot at home and abroad. Its purpose is to provide real-time energy supply for portable micro-power electronic products, remote sensing and monitoring systems, etc. Inconvenient use caused by insufficient or exhausted power, and environmental pollution caused by discarded batteries. Existing research results have shown that only when the fundamental frequency of the piezoelectric energy harvester adapts to the environmental vibration frequency can it have a high power generation capacity and electromechanical energy conversion efficiency. However, the frequency of the vibration source in the real environment is usually low. For example, the vibration induced by the operation of various vehicles and human body movement is usually only a dozen or tens of hertz, and the amplitude is relatively large; while the fundamental frequency of the piezoelectric vibrator itself is usually high. Usually hundreds or even thousands of hertz, it cannot be directly used for low-frequency vibration energy recovery. Even a cantilever beam piezoelectric vibrator with a low fundamental frequency needs to install lumped mass blocks at the end to achieve frequency reduction. The method of installing a mass block at the end of the piezoelectric vibrator of the cantilever beam is currently the most common method. The disadvantage is that when the concentrated mass is large, the piezoelectric vibrator has already undergone a large deformation in the non-working state, and it is easy to be affected by the excessive amplitude of the environment. , The vibration intensity is too high and damaged. In order to improve the bearing capacity and reliability of piezoelectric vibrators and realize large-amplitude and high-intensity vibration energy recovery, circular and stacked piezoelectric vibrators are also often used to construct vibration energy harvesters, but the resonance of such piezoelectric vibrators The frequency is higher, the resonance frequency of a single circular piezoelectric vibrator is several thousand hertz, and the fundamental frequency of the piezoelectric stack is as high as ten thousand hertz. In addition, the current piezoelectric energy harvester is basically composed of a single piezoelectric vibrator. Because of its limited power generation capacity, real-time power supply cannot be realized, and only energy storage-intermittent power supply can be used to work.

Contents of the invention

The invention provides a multi-vibrator series piezoelectric energy harvester to solve the problems of high resonance frequency, low reliability, limited power generation capacity and frequency bandwidth of the existing piezoelectric vibration energy harvester.

The technical solution adopted in the present invention is: the housing is installed on the base through screws, the card seat is installed on the base through screws and placed in the housing, and 1-50 piezoelectric transducers are placed in series in the housing The piezoelectric transducer is composed of two piezoelectric vibrators riveted on the ring frame through rivets; the piezoelectric vibrator is formed by bonding a metal substrate and a piezoelectric chip; the first series piezoelectric transducer The energy device is clamped with the deck, and the two adjacent piezoelectric transducers are clamped with bayonet pins; the last piezoelectric transducer in series is clamped with the claw of the pin shaft, The pin shaft protrudes out of the housing through the through hole at the upper end of the housing, and a mass block is installed on the thread of the pin shaft through a nut; the pin shaft is sequentially covered with a first spring and a second spring from bottom to top, and The first spring is crimped on the transducer housing through the shoulder of the pin shaft, and the second spring is crimped on the transducer housing through the mass block; the circuit board is installed on the transducer housing through screws The two piezoelectric vibrators on the same piezoelectric transducer are connected through wire group 1, and the two piezoelectric vibrators of different piezoelectric transducers are connected through wire group 2, and then connected to the circuit board through wire group 3. connect.

In the present invention, the first spring and the second spring respectively play the role of tension limit and compression limit to prevent the piezoelectric vibrator from being damaged due to excessive deformation, and the second spring also bears the gravity of the mass block. The first spring, the second spring and the piezoelectric transducer are in parallel structure mechanically, and their equivalent stiffness is , the resonant frequency of the energy harvester is ,in and are the stiffnesses of the first and second springs, respectively, is the equivalent stiffness of multiple piezoelectric vibrators connected in series, is the stiffness of a single piezoelectric vibrator, m is the mass of the mass block, and n is the number of piezoelectric vibrators. According to the formula for calculating the resonant frequency of the energy harvester, increasing the mass of the mass block and the number of piezoelectric vibrators can effectively reduce the resonant frequency of the energy harvester.

In order to ensure that the piezoelectric vibrator is not subjected to external force in a static state and will not be damaged when the amplitude of the mass block is too large, the formula for calculating the mass of the mass block is ,in , are the compression amounts of the first spring and the second spring when the energy harvester is at rest, is the acceleration of gravity; the maximum compressible amount of the two springs is equal during dynamic operation, and the calculation formula is ,in It is the maximum deformation that a single piezoelectric vibrator can bear.

In the natural state, the piezoelectric vibrator is not affected by external force, and the gravity of the mass is borne by the second spring at this time. When the housing is excited by environmental vibration, the mass block drives the pin shaft and the piezoelectric transducer to vibrate up and down, so that the piezoelectric vibrator produces bending deformation and converts mechanical energy into electrical energy. When the actual amplitude of the mass is greater than When the first spring or the second spring reaches the maximum compression amount, that is, it is no longer compressed, the inertial force of the mass block is transmitted to the housing through the first spring or the second spring, so as to avoid the damage of the piezoelectric vibrator due to excessive deformation .

Features and advantages of the present invention are: Using multiple piezoelectric vibrators in series and larger masses, the system has a low resonance frequency and strong power generation capacity; Two spring limiters are used to prevent the piezoelectric vibrator from being damaged due to excessive deformation, and the reliability is high.

Description of drawings

Fig. 1 is a structural diagram of a static piezoelectric energy harvester in a preferred embodiment of the present invention;

Fig. 2 is the sectional view of piezoelectric transducer in a preferred embodiment of the present invention;

Fig. 3 is the top view of Fig. 2;

Fig. 4 is a schematic structural view of the detent in a preferred embodiment of the present invention;

Fig. 5 is A-A sectional view of Fig. 4;

Fig. 6 is the voltage-frequency characteristic curve of the energy harvester when different concentrated masses in a preferred embodiment of the present invention;

Fig. 7 is an electric energy-frequency characteristic curve of the energy harvester with different numbers of piezoelectric vibrators in a preferred embodiment of the present invention.

Specific implementation methods :

The housing 1 is installed on the base 2 by screws, and the bottom plate 3-1 of the deck 3 is installed on the base 2 by screws and placed in the housing 1; 1-50 piezoelectric transducers 4 are placed in series In the housing 1, the piezoelectric transducer 4 is composed of two annular piezoelectric vibrators 4-2 riveted on the annular skeleton 4-1 through rivets 4-3; the piezoelectric vibrators 4-2 are composed of annular The metal substrate 4-2-1 and the annular piezoelectric wafer 4-2-2 are bonded together; the first piezoelectric transducer 4 connected in series is connected to the socket 3 through a through hole H thereon. The claws 3-2 are clamped, and the two adjacent piezoelectric transducers 4 are clamped by the bayonet pin 5; a through hole H of the last series-connected piezoelectric transducer 4 is connected to the pin shaft 6's claw 6-1 snaps, the pin 6 protrudes out of the shell 1 through the through hole 1-1 on the upper end of the shell 1, and the thread 6-3 of the pin 6 is installed with a mass through a nut 9 Block 10; the pin shaft 6 is sequentially covered with a first spring 7 and a second spring 8 from bottom to top, and the first spring 7 is crimped on the transducer housing through the shoulder 6-2 of the pin shaft 6 1, the second spring 8 is crimped on the transducer housing 1 through the mass 10; the circuit board 11 is installed on the side wall of the transducer housing 1 through screws, and the same piezoelectric transducer 4 The two piezoelectric vibrators 4-2 are connected through wire group one 12, the two piezoelectric vibrators 4-2 of different piezoelectric transducers 4 are connected through wire group two 13, and the piezoelectric vibrator 4-2 is connected through wire group three 14 is connected with circuit board 11.

In the present invention, the first spring 7 and the second spring 8 respectively play the role of tension limit and compression limit to avoid the piezoelectric vibrator 4-2 being damaged due to excessive deformation, and the second spring also bears the weight of the mass block 10 gravity. Described first spring 7, second spring 8 and piezoelectric transducer 4 are mechanically in parallel structure, and its equivalent stiffness is , the resonant frequency of the energy harvester is ,in and are respectively the stiffness of the first spring 7 and the second spring 8, is the equivalent stiffness of multiple piezoelectric vibrators 4-2 connected in series, is the stiffness of a single piezoelectric vibrator 4-2, m is the mass of the mass block 10, and n is the number of piezoelectric vibrators 4-2. According to the formula for calculating the resonant frequency of the energy harvester, increasing the mass of the mass block and the number of piezoelectric vibrators can effectively reduce the resonant frequency of the energy harvester.

In order to ensure that the piezoelectric vibrator 4-2 is not subjected to external force in a static state and will not be damaged when the amplitude of the mass block 10 is too large, the formula for calculating the mass of the mass block 10 is ,in , are respectively the compression amounts of the first spring 7 and the second spring 8 when the energy harvester is at rest, is the acceleration of gravity; the maximum compressible amount of the two springs is equal during dynamic operation, and the calculation formula is ,in is the maximum deformation that a single piezoelectric vibrator 4-2 can bear.

In a natural state, the piezoelectric vibrator 4-2 is not subjected to external force, and the gravity of the mass block 10 is borne by the second spring. When the shell is excited by the environment vibration, the mass block 10 drives the pin shaft 6 and the piezoelectric transducer 4 to vibrate up and down, so that the piezoelectric vibrator 4-2 is bent and deformed, and the mechanical energy is converted into electrical energy. When the actual amplitude of mass 10 is greater than , the first spring 7 or the second spring 8 reaches the maximum compression amount, that is, it is no longer compressed, and the inertial force of the mass block 10 is transmitted to the housing 1 through the first spring 7 or the second spring 8, thereby avoiding the piezoelectric vibrator 4-2 was damaged due to excessive deformation.

Claims (3)

1. the tandem of oscillator a more than piezoelectric harvester, it is characterized in that: housing is arranged on base by screw, deck is arranged on base by screw, and 1-50 PZT (piezoelectric transducer) series connection is placed in described housing; PZT (piezoelectric transducer) is consisted of rivet two piezoelectric vibrators on skeleton; Piezoelectric vibrator is by metal substrate and piezoelectric chip is bonding forms; PZT (piezoelectric transducer) and the deck clamping of first series connection, two adjacent PZT (piezoelectric transducer)s pass through bayonet lock clamping; The PZT (piezoelectric transducer) of last series connection and the claw clamping of bearing pin one end, bearing pin stretches out outside housing by the through hole on housing, and the other end of bearing pin is provided with mass; Described bearing pin overlaps from bottom to top successively the first spring and the second spring, and described first spring is pressed on transducer housing by the bearing pin shaft shoulder, described second spring is pressed on transducer housing by mass; Circuit board is arranged on transducer housing sidewall by screw, and two piezoelectric vibrators on same PZT (piezoelectric transducer) are connected by wire group one, and two piezoelectric vibrators of different PZT (piezoelectric transducer) are connected by wire group two, then are connected with circuit board by wire group three.

2. one many oscillators tandem piezoelectric harvester according to claim 1, is characterized in that: the resonance frequency of energy accumulator is calculated as follows: wherein k ₁and k ₂be respectively the rigidity of the first spring and the second spring, k _pfor the rigidity of single piezoelectric vibrator, m is the quality of mass, and n is the quantity of piezoelectric vibrator.

3. one many oscillators tandem piezoelectric harvester according to claim 2, it is characterized in that: after spring rate is determined, the quality calculation method of mass is: wherein δ _{1, j}, δ _{2, j}be respectively energy accumulator static time the first spring and the decrement of the second spring, g is acceleration of gravity.