An omnidirectional piezoelectric energy harvesting and vibration monitoring system

Abstract

The present invention discloses an omnidirectional piezoelectric energy capture and vibration monitoring system, which includes a signal acquisition mechanism and an interface circuit. The signal acquisition mechanism is composed of a support base and three conventional cantilever beam piezoelectric devices of the same specifications that are perpendicular to each other. The three conventional cantilever beam piezoelectric devices sense vibration components in three directions. Three energy capture submodules capture the vibration components in three directions and transmit them to a multi-input flyback converter module for conversion to obtain electrical signals for power supply. Three vibration sensing submodules collect signals corresponding to vibration components in three directions in space and transmit them to a signal processing module. The signal processing module calculates the amplitude, direction angle and frequency of the overall vibration acceleration felt by the signal acquisition mechanism. The system has the advantages of strong environmental adaptability, energy capture efficiency and acceleration detection accuracy are not affected by the vibration direction, and has high energy capture efficiency and high acceleration detection accuracy when the vibration direction is in any direction.

Description

Technical Field

[0001] The present invention relates to a vibration monitoring system, in particular to an omnidirectional piezoelectric energy capture and vibration monitoring system. Background Art

[0002] Piezoelectric materials exhibit a positive piezoelectric effect. When stimulated by environmental vibrations, they strain and output a piezoelectric voltage signal. By processing this piezoelectric voltage signal using appropriate vibration sensing circuits and methods, the vibration acceleration experienced by the piezoelectric material can be determined. This is known as piezoelectric vibration sensing. Furthermore, by utilizing appropriate energy capture circuits and methods, the energy converted by the piezoelectric material can be extracted to power low-power microelectronic devices such as wireless sensor nodes, extending their battery life. This is known as piezoelectric energy capture.

[0003] A Chinese patent with application number CN202110032826.6 discloses a self-powered wireless vibration monitoring node based on a single piezoelectric device. This solution uses a single piezoelectric device for vibration sensing and energy capture, where the energy capture circuit is used to extract the electrical energy converted by the piezoelectric device, and the vibration sensing circuit is used to collect the piezoelectric voltage signal converted by the piezoelectric device. At the same time, the piezoelectric voltage signal is processed and transmitted in combination with a microcontroller module and a wireless transmission module.

[0004] However, this self-powered wireless vibration monitoring node can only capture vibration energy in a direction perpendicular to the piezoelectric device and can only detect vibration acceleration in a direction perpendicular to the piezoelectric device. When the vibration direction is aligned with the direction perpendicular to the piezoelectric device, it has high energy capture efficiency and high acceleration detection accuracy. However, in actual application environments, the vibration direction of the vibration source is affected by the environment and is often unknown, arbitrary, and variable. When the vibration direction deviates from the direction perpendicular to the piezoelectric device, the self-powered wireless vibration monitoring node has low energy capture efficiency and low acceleration detection accuracy. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an omnidirectional piezoelectric energy capture and vibration monitoring system with strong environmental adaptability, energy capture efficiency and acceleration detection accuracy that are not affected by the vibration direction, and high energy capture efficiency and high acceleration detection accuracy when the vibration direction is in any direction.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: an omnidirectional piezoelectric energy capture and vibration monitoring system, including a signal acquisition mechanism and an interface circuit, the signal acquisition mechanism includes a support seat and three conventional cantilever beam piezoelectric devices of the same specifications, the three conventional cantilever beam piezoelectric devices are respectively installed on the support seat, and any two conventional cantilever beam piezoelectric devices in space are in a vertical state, the installation directions of the three conventional cantilever beam piezoelectric devices intersect at the geometric center of the support seat, the geometric center of the support seat is taken as the origin O, and the installation directions of the three conventional cantilever beam piezoelectric devices are respectively used as the X direction, Y direction and Z direction to construct a spatial rectangular coordinate system XYZ, at this time, three mutually perpendicular planes are obtained, namely XOY, XO Z, YOZ; a conventional cantilever beam piezoelectric device with its installation direction along the X direction is referred to as an X-direction conventional cantilever beam piezoelectric device, a conventional cantilever beam piezoelectric device with its installation direction along the Y direction is referred to as a Y-direction conventional cantilever beam piezoelectric device, and a conventional cantilever beam piezoelectric device with its installation direction along the Z direction is referred to as a Z-direction conventional cantilever beam piezoelectric device. The X-direction conventional cantilever beam piezoelectric device is used to sense the X-direction vibration acceleration component and convert it into a corresponding differential AC voltage output, the Y-direction conventional cantilever beam piezoelectric device is used to sense the Y-direction vibration acceleration component and convert it into a corresponding differential AC voltage output, and the Z-direction conventional cantilever beam piezoelectric device is used to sense the Z-direction vibration acceleration component and convert it into a corresponding differential AC voltage output;

[0007] The interface circuit includes an energy capture module, a vibration sensing module, a multi-input flyback converter module, a signal processing module and a wireless transmission module. The energy capture module includes three identical energy capture submodules, which are respectively referred to as the X-direction energy capture submodule, the Y-direction energy capture submodule and the Z-direction energy capture submodule. The X-direction energy capture submodule is used to access the differential AC voltage output by the conventional cantilever beam piezoelectric device in the X direction and convert the differential AC voltage into a first DC voltage and output it to the multi-input flyback converter module. The Y-direction energy capture submodule is used to access the conventional cantilever beam piezoelectric device in the Y direction. The Z-direction energy capture submodule is used to receive the differential AC voltage output by the Z-direction conventional cantilever beam piezoelectric device and convert the differential AC voltage into a second DC voltage and output it to the multi-input flyback converter module; the Z-direction energy capture submodule is used to receive the differential AC voltage output by the Z-direction conventional cantilever beam piezoelectric device and convert the differential AC voltage into a third DC voltage and output it to the multi-input flyback converter module; the multi-input flyback converter module performs DC conversion, linear voltage regulation, and electrical energy storage on the first DC voltage, the second DC voltage, and the third DC voltage input therein, and simultaneously provides a working power supply voltage for the vibration sensing module, the signal processing module, and the wireless transmitting module;

[0008] The vibration sensing module includes three vibration sensing submodules with the same structure, which are respectively called X-direction vibration sensing submodule, Y-direction vibration sensing submodule and Z-direction vibration sensing submodule. The X-direction vibration sensing submodule senses the differential AC voltage output by the conventional cantilever beam piezoelectric device in the X direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and performs shaping triggering to generate a square wave signal of the same frequency and output it to the signal processing module. The Y-direction vibration sensing submodule senses the differential AC voltage output by the conventional cantilever beam piezoelectric device in the Y direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and performs shaping triggering to generate a square wave signal of the same frequency and output it to the signal processing module. Generate a same-frequency square wave signal and output it to the signal processing module. The Z-direction vibration sensor submodule senses the differential AC voltage output by the Z-direction conventional cantilever beam piezoelectric device and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and performs shaping triggering to generate a same-frequency square wave signal and output it to the signal processing module. The signal processing module determines the X-direction vibration acceleration component, the Y-direction vibration acceleration component, and the Z-direction vibration acceleration component based on the three peak voltage signals and three same-frequency square wave signals input therein, and then calculates the amplitude, direction angle, and frequency of the overall vibration acceleration felt by the signal acquisition mechanism, and transmits them to the wireless transmission module for wireless transmission.

[0009] Each of the conventional cantilever beam piezoelectric devices has a positive polarity output terminal and a negative polarity output terminal, each of the energy capture submodules has a positive input terminal, a negative input terminal, an output terminal and a ground terminal, the multi-input flyback converter module has a first input terminal, a second input terminal, a third input terminal, a power output terminal and a ground terminal, each of the vibration sensor submodules has an input terminal, a peak output terminal, a square wave output terminal, a power input terminal and a ground terminal, the signal processing module has a first peak input terminal, a first square wave input terminal, a second peak input terminal, a second square wave input terminal, a third peak input terminal, a third square wave input terminal, a data bus, a power input terminal and a ground terminal, the wireless transmission module has a data bus, The power input terminal and the ground terminal; the positive polarity output terminal of the conventional cantilever beam piezoelectric device in the X direction is connected to the positive input terminal of the energy capture submodule in the X direction, the negative polarity output terminal of the conventional cantilever beam piezoelectric device in the X direction is connected to the negative input terminal of the energy capture submodule in the X direction, the positive polarity output terminal of the conventional cantilever beam piezoelectric device in the Y direction is connected to the positive input terminal of the energy capture submodule in the Y direction, the negative polarity output terminal of the conventional cantilever beam piezoelectric device in the Y direction is connected to the negative input terminal of the energy capture submodule in the Y direction, the positive polarity output terminal of the conventional cantilever beam piezoelectric device in the Z direction is connected to the positive input terminal of the energy capture submodule in the Z direction, and the positive polarity output terminal of the conventional cantilever beam piezoelectric device in the Z direction is connected to the positive input terminal of the energy capture submodule in the Z direction. The negative polarity output end of the conventional cantilever beam piezoelectric device is connected to the negative input end of the Z-direction energy capture submodule, the positive polarity output end of the conventional cantilever beam piezoelectric device in the X-direction is connected to the input end of the X-direction vibration sensor submodule, the positive polarity output end of the conventional cantilever beam piezoelectric device in the Y-direction is connected to the input end of the Y-direction vibration sensor submodule, the positive polarity output end of the conventional cantilever beam piezoelectric device in the Z-direction is connected to the input end of the Z-direction vibration sensor submodule, the output end of the X-direction energy capture submodule is connected to the first input end of the multi-input flyback converter module, and the output end of the Y-direction energy capture submodule is connected to the second input end of the multi-input flyback converter module. The output end of the Z-direction energy capture submodule is connected to the third input end of the multi-input flyback converter module, the peak output end of the X-direction vibration sensor submodule is connected to the first peak input end of the signal processing module, the square wave output end of the X-direction vibration sensor submodule is connected to the first square wave input end of the signal processing module, the peak output end of the Y-direction vibration sensor submodule is connected to the second peak input end of the signal processing module, the square wave output end of the Y-direction vibration sensor submodule is connected to the second square wave input end of the signal processing module, and the peak output end of the Z-direction vibration sensor submodule is connected to the third peak input end of the signal processing module.The square wave output of the Z-direction vibration sensor submodule is connected to the third square wave input of the signal processing module. The data bus of the signal processing module is connected to the data bus of the wireless transmitter module. The power output of the multi-input flyback converter module is respectively connected to the power input of the X-direction vibration sensor submodule, the power input of the Y-direction vibration sensor submodule / the power input of the Z-direction vibration sensor submodule, the power input of the signal processing module, and the power input of the wireless transmitter module. The ground of the multi-input flyback converter module, the ground of the X-direction vibration sensor submodule, the ground of the Y-direction vibration sensor submodule, the ground of the Z-direction vibration sensor submodule, the ground of the signal processing module, and the ground of the wireless transmitter module are connected. The positive and negative output terminals of the conventional cantilever beam piezoelectric device in the X-direction are used to output a differential AC voltage V. PZTX+ and V PZTX－ The positive polarity output terminal and the negative polarity output terminal of the conventional cantilever beam piezoelectric device in the Y direction are used to output a differential AC voltage V PZTY+ and V PZTY－ The positive polarity output terminal and the negative polarity output terminal of the conventional cantilever beam piezoelectric device in the Z direction are used to output a differential AC voltage V PZTZ+ and V PZTZ－ The output terminal of the X-direction energy capture submodule is used to output a first DC voltage, and the first DC voltage is recorded as V EHX The output terminal of the Y-direction energy capture submodule is used to output a second DC voltage, and the second DC voltage is recorded as V EHY The output terminal of the Z-direction energy capture submodule is used to output a third DC voltage, and the third DC voltage is recorded as V EHZ The peak output terminal of the X-direction vibration sensor module is used to output a peak voltage signal, which is recorded as V PEAKX The peak output terminal of the Y-direction vibration sensor module is used to output a peak voltage signal, which is recorded as V PEAKY The peak output terminal of the Z-direction vibration sensor module is used to output a peak voltage signal, which is recorded as V PEAKZ The square wave output terminal of the X-direction vibration sensor module is used to output a square wave signal of the same frequency, and the square wave signal of the same frequency is recorded as V FREQX The square wave output terminal of the Y-direction vibration sensor module is used to output a square wave signal of the same frequency, and the square wave signal of the same frequency is recorded as V FREQY The square wave output terminal of the Z-direction vibration sensor module is used to output a square wave signal of the same frequency, and the square wave signal of the same frequency is recorded as V FREQZ ,

[0010] The signal processing module pre-stores the amplitude-frequency characteristic curve and timing period T of the conventional cantilever beam piezoelectric device. The signal processing module is based on the three peak voltage signals V input therein. PEAKX 、V PEAKY 、V PEAKZ And 3 channels of same frequency square wave signal V FREQX 、V FREQY 、V FREQZ , determine the X-direction vibration acceleration component a felt by the conventional cantilever beam piezoelectric device in the X direction X , Y direction vibration acceleration component a felt by conventional cantilever beam piezoelectric device in Y direction Y The Z-direction vibration acceleration component a felt by the conventional cantilever beam piezoelectric device in the Z direction Z , and then calculate the amplitude, direction angle and frequency of the overall vibration acceleration; the signal processing module starts timing after power is turned on, and when the three peak voltage signals V PEAKX 、V PEAKY 、V PEAKZ And 3 channels of same frequency square wave signal V FREQX 、V FREQY 、V FREQZ When inputted into it, the signal processing module processes the 3-way peak voltage signal V PEAKX 、V PEAKY 、V PEAKZ Continuous AD sampling is performed simultaneously, and the three channels of the same frequency square wave signal V are inputted. FREQX 、V FREQY 、V FREQZ Perform rising edge counting respectively. When sampling and timing reach a timing cycle T, stop counting and AD sampling, and perform mathematical processing on the sampling value and counting value obtained in the timing cycle, and then enter the next timing cycle to restart counting and sampling, and repeat the process. Among them, the specific process of mathematical processing on the sampling value and counting value obtained in the timing cycle at the end of each timing cycle T is as follows: the AD sampling frequency is recorded as F S , then the signal processing module in a timing period T processes the three peak voltage signals V PEAKX 、V PEAKY 、V PEAKZ Perform S AD samplings respectively, where S = F S *T, 3-way peak voltage signal V PEAKX 、V PEAKY 、V PEAKZ Each has S sampling data, and calculates the peak voltage signal V PEAKX The average value V of S sample data PEAKX-AVG 、V PEAKYThe average value V of S sample data PEAKY-AVG and V PEAKZ The average value V of S sample data PEAKZ-AVG , determine V PEAKX-AVG 、V PEAKY-AVG and V PEAKZ-AVG The direction of the peak voltage signal corresponding to the maximum value is recorded as DIR, and DIR is one of X, Y, and Z. That is, the peak voltage signal output by the vibration sensor module in the DIR direction is the largest among the S sampling data obtained by AD sampling in a timing period T. The average value of the same frequency square wave signal V in a timing period T is recorded as FREQX The rising edge count value is recorded as N X , square wave signal with the same frequency V FREQY The rising edge count value is recorded as N Y , square wave signal with the same frequency V FREQZ The rising edge count value is recorded as N Z , the three-way square wave signal V FREQX 、V FREQY 、V FREQZ In the DIR direction, the rising edge count value of the square wave signal with the same frequency output by the vibration sensor module is retained and recorded as N. At this time, N=N DIR , N DIR N X 、N Y 、N Z The frequency of the overall vibration acceleration sensed by the signal acquisition mechanism is recorded as F V , at this time there is F V =N DIR / T; Under the same vibration excitation conditions, the peak voltage signal V PEAKX The piezoelectric open circuit voltage is V PEAKX-POC , peak voltage signal V PEAKY The piezoelectric open circuit voltage is V PEAKY-POC , peak voltage signal V PEAKZ The piezoelectric open circuit voltage is V PEAKZ-POC , let V PEAKX-POC =0.5*k*V PEAKX-AVG 、V PEAKY-POC =0.5*k*V PEAKY-AVG 、V PEAKZ-POC =0.5*k*V PEAKZ-AVG , where k is the inverse of the voltage divider coefficient of the vibration sensor module; based on the three piezoelectric open circuit voltages V PEAKX-POC 、V PEAKY-POC 、V PEAKZ-POC and vibration frequency F VThe amplitude-frequency characteristic curve of the conventional cantilever beam piezoelectric device is searched and queried to obtain the amplitude of the overall vibration acceleration in the X, Y and Z directions, where the amplitude of the vibration acceleration component in the X direction is a X , the amplitude of the vibration acceleration component in the Y direction a Y , the amplitude of the vibration acceleration component in the Z direction a Z , and calculate the amplitude of the overall vibration acceleration The direction angle of the overall vibration acceleration is the three angles between it and the X direction, Y direction, and Z direction, which are denoted as α, β, and γ respectively. α=arccos(a X / a)、β=arccos(a Y / a),γ=arccos(a Z / a).

[0011] Each of the energy capture submodules includes a first PMOS field effect transistor, a second PMOS field effect transistor, a first NMOS field effect transistor, a second NMOS field effect transistor, a first diode, a first capacitor, a first NPN transistor and a first PNP transistor. The first capacitor is a non-polarized capacitor. The source of the first PMOS field effect transistor, the source of the second PMOS field effect transistor, the positive electrode of the first diode, the base of the first PNP transistor and the collector of the first NPN transistor are connected. The drain of the first PMOS field effect transistor, the gate of the second PMOS field effect transistor, the drain of the first NMOS field effect transistor and the gate of the second NMOS field effect transistor are connected, and their connection end is the positive input end of the energy capture submodule. The gate of the first PMOS field effect transistor, the drain of the second PMOS field effect transistor, the gate of the first NMOS field effect transistor, and the drain of the second NMOS field effect transistor are connected, and their connection end is the negative input end of the energy capture submodule, the cathode of the first diode, the collector of the first PNP transistor and one end of the first capacitor are connected, the source of the first NMOS field effect transistor, the source of the second NMOS field effect transistor and the other end of the first capacitor are connected and their connection end is the ground end of the energy capture submodule, the ground end of the energy capture submodule is grounded, the collector of the first PNP transistor and the base of the first NPN transistor are connected, and the emitter of the first NPN transistor is the output end of the energy capture submodule. In this energy capture submodule, the four field-effect transistors, namely the first PMOS field-effect transistor, the second PMOS field-effect transistor, the first NMOS field-effect transistor, and the second NMOS field-effect transistor, constitute a dual cross-coupled rectification structure, which actually plays the role of a classic full-bridge rectifier and can reduce the voltage loss during the AC-DC conversion process. At the same time, this structure has extremely low energy loss. The first diode, the first capacitor and the two transistors realize the function of envelope detection and can complete synchronous switching. At the same time, the energy capture submodule uses all passive devices and automatically starts working under a certain piezoelectric input voltage condition. The circuit structure has extremely low power consumption.

[0012] The multi-input flyback converter module includes a second diode, a third diode, a fourth diode, a fifth diode, a flyback transformer, a first resistor, a second resistor, a second capacitor, a DC converter, a rechargeable lithium battery and a linear regulator. The flyback transformer includes a primary coil and a secondary coil, and the turns ratio is 1. The second capacitor is an electrolytic capacitor. The DC converter has an input terminal, an output terminal, an enable terminal and a ground terminal. The linear regulator has an input terminal, an output terminal and a ground terminal. The anode of the second diode is the first input terminal of the multi-input flyback converter module, the anode of the third diode is the second input terminal of the multi-input flyback converter module, and the anode of the fourth diode is the third input terminal of the multi-input flyback converter module. The cathode of the second diode, the cathode of the third diode, and the cathode of the fourth diode are connected to one end of the primary coil of the flyback transformer. One end of the secondary coil of the flyback transformer is connected to the positive electrode of the fifth diode, the negative electrode of the fifth diode, the positive electrode of the second capacitor, one end of the first resistor and the input end of the DC converter are connected, the other end of the first resistor and one end of the second resistor are connected to the enable end of the DC converter, the output end of the DC converter, the positive electrode of the rechargeable lithium battery and the input end of the linear regulator are connected, the output end of the linear regulator is the power output end of the multi-input flyback converter module, the ground end of the DC converter, the negative electrode of the rechargeable lithium battery, the other end of the second resistor, the negative electrode of the second capacitor, the other end of the primary coil of the flyback transformer, the other end of the secondary coil of the flyback transformer and the ground end of the linear regulator are connected and their connection ends are the ground end of the multi-input flyback converter module, and the ground end of the multi-input flyback converter module is grounded. The multi-input flyback converter module performs multi-input flyback voltage conversion on the three DC voltages input therein and then charges the second capacitor. The second capacitor outputs a voltage to the enable terminal of the DC converter after voltage division by a pair of voltage dividers, namely a first resistor and a second resistor. The voltage at the enable terminal is recorded as V EN When V EN When V is greater than the preset enable threshold voltage in the DC converter (the enable threshold voltage is determined by the chip itself), the DC converter starts working and the second capacitor charges the rechargeable lithium battery through the DC converter; when V EN When the voltage is lower than the enable threshold, the DC converter stops working and the rechargeable lithium battery outputs a stable working power supply voltage V through the linear regulator. CCThe multi-input flyback converter module supplies power to the vibration sensor module, microcontroller module, and wireless transmitter module. It can simultaneously perform flyback conversion on multiple input DC voltages and charge them into a second capacitor. This is then processed uniformly using a shared DC converter and linear regulator. This results in a compact circuit structure and high energy conversion efficiency.

[0013] Each of the vibration sensor submodules includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a sixth diode, a seventh diode, a first operational amplifier, a second operational amplifier, a comparator and a third capacitor. The first operational amplifier and the second operational amplifier both have a non-inverting input terminal, an inverting input terminal, an output terminal, a power supply terminal and a ground terminal. The comparator has a non-inverting input terminal, an inverting input terminal, an output terminal, a power supply terminal and a ground terminal. One end of the third resistor is the input terminal of the vibration sensor submodule, the other end of the third resistor, one end of the fourth resistor, the non-inverting input terminal of the first operational amplifier and the non-inverting input terminal of the comparator are connected, the inverting input terminal of the first operational amplifier, the positive electrode of the sixth diode and one end of the seventh resistor are connected, the output terminal of the first operational amplifier, the negative electrode of the sixth diode and the positive electrode of the seventh diode are connected, the other end of the seventh resistor, the inverting input terminal of the second operational amplifier The phase input end is connected to the output end of the second operational amplifier and its connection end is the peak output end of the vibration sensor submodule, the cathode of the seventh diode, the non-inverting input end of the second operational amplifier and one end of the third capacitor are connected, one end of the fifth resistor and one end of the sixth resistor are connected to the inverting input end of the comparator, the output end of the comparator is the square wave output end of the vibration sensor submodule, the power supply end of the first operational amplifier, the power supply end of the second operational amplifier, the power supply end of the comparator and the other end of the fifth resistor are connected and the connection end is the power input end of the vibration sensor module, the other end of the fourth resistor, the other end of the sixth resistor and the other end of the third capacitor, the ground end of the first operational amplifier, the ground end of the second operational amplifier and the ground end of the comparator are connected and the connection end is the ground end of the vibration sensor submodule, and the ground end of the vibration sensor submodule is grounded. The vibration sensor module uses only one comparator to trigger the shaping of the piezoelectric voltage and generate a square wave of the same frequency. At the same time, the operational amplifier and comparator in the circuit are powered by a single power supply, thereby reducing the complexity of the circuit and achieving multiple necessary functional operations while maintaining a simple circuit structure.

[0014] Compared with the prior art, the advantage of the present invention is that a signal acquisition mechanism is formed by a support base and three conventional cantilever beam piezoelectric devices, each acquisition unit includes three conventional cantilever beam piezoelectric devices of the same specifications, respectively installed on the support base, and any two conventional cantilever beam piezoelectric devices are in a vertical state in space, the installation directions of the three conventional cantilever beam piezoelectric devices intersect at the geometric center of the support base, the geometric center of the support base is taken as the origin O, and the installation directions of the three conventional cantilever beam piezoelectric devices are respectively used as the X direction, Y direction and Z direction to construct a spatial rectangular coordinate system XYZ, at this time, three mutually perpendicular planes are obtained, namely XOY, XOZ, YOZ; the conventional cantilever beam piezoelectric device with the installation direction along the X direction is called the X-direction conventional cantilever beam piezoelectric device, the conventional cantilever beam piezoelectric device with the installation direction along the Y direction is called the Y-direction conventional cantilever beam piezoelectric device, and the conventional cantilever beam piezoelectric device with the installation direction along the Z direction is called the Z-direction conventional cantilever beam piezoelectric device. The X-direction conventional cantilever beam piezoelectric device is used to sense the X-direction vibration acceleration component and convert it into the corresponding differential AC voltage output. The Y-direction conventional cantilever beam piezoelectric device is used to sense the Y-direction vibration acceleration component and convert it into the corresponding differential AC voltage output. The Z-direction conventional cantilever beam piezoelectric device is used to sense the Y-direction vibration acceleration component and convert it into the corresponding differential AC voltage output. The interface circuit is used to sense the Z-direction vibration acceleration component and convert it into a corresponding differential AC voltage output. The interface circuit includes an energy capture module, a vibration sensing module, a multi-input flyback converter module, a signal processing module and a wireless transmission module. The energy capture module includes three identical energy capture submodules, which are respectively called the X-direction energy capture submodule, the Y-direction energy capture submodule and the Z-direction energy capture submodule. The X-direction energy capture submodule is used to access the differential AC voltage output by the conventional cantilever beam piezoelectric device in the X direction and convert the differential AC voltage into a first DC voltage and output it to the multi-input flyback converter module. The Y-direction energy The capture submodule is used to access the differential AC voltage output by the conventional cantilever beam piezoelectric device in the Y direction and convert the differential AC voltage into a second DC voltage and output it to the multi-input flyback converter module. The Z-direction energy capture submodule is used to access the differential AC voltage output by the conventional cantilever beam piezoelectric device in the Z direction and convert the differential AC voltage into a third DC voltage and output it to the multi-input flyback converter module. The multi-input flyback converter module performs DC conversion, linear voltage regulation, and electrical energy storage on the first DC voltage, the second DC voltage, and the third DC voltage input therein, and simultaneously provides an operating power supply voltage for the vibration sensing module, the signal processing module, and the wireless transmission module.The vibration sensing module includes three vibration sensing submodules with the same structure, which are respectively called X-direction vibration sensing submodule, Y-direction vibration sensing submodule and Z-direction vibration sensing submodule. The X-direction vibration sensing submodule senses the differential AC voltage output by the conventional cantilever beam piezoelectric device in the X direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and shaping trigger to generate a square wave signal of the same frequency and output it to the signal processing module. The Y-direction vibration sensing submodule senses the differential AC voltage output by the conventional cantilever beam piezoelectric device in the Y direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and shaping trigger to generate a square wave signal of the same frequency and output it to the signal processing module. The AC voltage is peak tracked to generate a peak voltage signal and shaped to trigger to generate a square wave signal of the same frequency and output to the signal processing module. The Z-direction vibration sensing submodule senses the differential AC voltage output by the conventional cantilever beam piezoelectric device in the Z direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and shaped to trigger to generate a square wave signal of the same frequency and output to the signal processing module. The signal processing module determines the vibration acceleration component in the X direction, the vibration acceleration component in the Y direction and the vibration acceleration component in the Z direction based on the three peak voltage signals and three square wave signals of the same frequency input therein, and then calculates the signal. The amplitude, direction angle and frequency of the overall vibration acceleration felt by the signal collection mechanism are transmitted to the wireless transmission module for wireless transmission. The present invention can sense the vibration components of the vibration acceleration in any direction in space in the X, Y and Z directions through conventional cantilever beam piezoelectric devices in the X direction, conventional cantilever beam piezoelectric devices in the Y direction and conventional cantilever beam piezoelectric devices in the Z direction. On the one hand, the vibration component signals in the three directions are captured by the X direction energy capture submodule, the Y direction energy capture submodule and the Z direction energy capture submodule, and are transmitted to the multi-input flyback converter module for conversion into electrical signals for power supply. This system achieves omnidirectional energy capture and power supply. Furthermore, the X-, Y-, and Z-direction vibration sensing submodules sense vibration components in three spatial directions and output corresponding electrical signals to a signal processing module. The signal processing module then calculates the amplitude, azimuth, and frequency of the overall vibration acceleration sensed by the signal acquisition mechanism. This system has strong environmental adaptability, and its energy capture efficiency and acceleration detection accuracy are unaffected by vibration direction. High energy capture efficiency and high acceleration detection accuracy are maintained regardless of vibration direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the omnidirectional piezoelectric energy capture and vibration monitoring system of the present invention;

[0016] Figure 2 A circuit diagram of the energy capture submodule of the omnidirectional piezoelectric energy capture and vibration monitoring system of the present invention;

[0017] Figure 3A circuit diagram of a multi-input flyback converter module of the omnidirectional piezoelectric energy capture and vibration monitoring system of the present invention;

[0018] Figure 4 This is a circuit diagram of the vibration sensor submodule of the omnidirectional piezoelectric energy capture and vibration monitoring system of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0020] Example: Figure 1As shown, an omnidirectional piezoelectric energy capture and vibration monitoring system includes a signal acquisition mechanism and an interface circuit. The signal acquisition mechanism includes a support base 1 and three conventional cantilever beam piezoelectric devices of the same specifications. The three conventional cantilever beam piezoelectric devices are respectively mounted on the support base 1, and any two conventional cantilever beam piezoelectric devices are perpendicular to each other in space. The mounting directions of the three conventional cantilever beam piezoelectric devices intersect at the geometric center of the support base 1. The geometric center of the support base 1 is taken as the origin O, and the mounting directions of the three conventional cantilever beam piezoelectric devices are respectively taken as the X direction, the Y direction and the Z direction to construct a spatial rectangular coordinate system XYZ. At this time, three mutually perpendicular planes are obtained, namely XOY, XOZ and YOZ. The conventional cantilever beam piezoelectric device with the installation direction along the X direction is called the X-direction conventional cantilever beam piezoelectric device PZTX, the conventional cantilever beam piezoelectric device with the installation direction along the Y direction is called the Y-direction conventional cantilever beam piezoelectric device PZTY, and the conventional cantilever beam piezoelectric device with the installation direction along the Z direction is called the Z-direction conventional cantilever beam piezoelectric device PZTZ. The X-direction conventional cantilever beam piezoelectric device PZTX is used to sense the X-direction vibration acceleration component and convert it into the corresponding differential AC voltage output. The Y-direction conventional cantilever beam piezoelectric device PZTY is used to sense the Y-direction vibration acceleration component and convert it into the corresponding differential AC voltage output. The Z-direction conventional cantilever beam piezoelectric device PZTZ is used to sense the Z-direction vibration acceleration component. The interface circuit includes an energy capture module 2, a vibration sensing module 4, a multi-input flyback converter module 3, a signal processing module 5 and a wireless transmission module 6. The energy capture module 2 includes three identical energy capture submodules, which are respectively called the X-direction energy capture submodule 2-X, the Y-direction energy capture submodule 2-Y and the Z-direction energy capture submodule 2-Z. The X-direction energy capture submodule 2-X is used to access the differential AC voltage output by the conventional cantilever beam piezoelectric device PZTX in the X direction and convert the differential AC voltage into a first DC voltage and output it to the multi-input flyback converter module 3. The Y-direction energy capture The energy capture submodule 2-Y is used to access the differential AC voltage output by the conventional cantilever beam piezoelectric device PZTY in the Y direction and convert the differential AC voltage into a second DC voltage and output it to the multi-input flyback converter module 3. The Z-direction energy capture submodule 2-Z is used to access the differential AC voltage output by the conventional cantilever beam piezoelectric device PZTZ in the Z direction and convert the differential AC voltage into a third DC voltage and output it to the multi-input flyback converter module 3. The multi-input flyback converter module 3 performs DC conversion, linear voltage regulation, and electrical energy storage on the first DC voltage, the second DC voltage, and the third DC voltage input therein, and simultaneously provides a working power supply voltage for the vibration sensing module 4, the signal processing module 5, and the wireless transmission module 6.The vibration sensing module 4 includes three vibration sensing submodules with the same structure, which are respectively called X-direction vibration sensing submodule 4-X, Y-direction vibration sensing submodule 4-Y and Z-direction vibration sensing submodule 4-Z. The X-direction vibration sensing submodule 4-X senses the differential AC voltage output by the conventional cantilever beam piezoelectric device PZTX in the X direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and performs shaping triggering to generate a square wave signal of the same frequency and output it to the signal processing module 5. The Y-direction vibration sensing submodule 4-Y senses the differential AC voltage output by the conventional cantilever beam piezoelectric device PZTY in the Y direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal. The Z-direction vibration sensing submodule 4-Z senses the differential AC voltage output by the conventional cantilever beam piezoelectric device PZTZ in the Z direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal. It also generates a square wave signal with the same frequency and outputs it to the signal processing module 5 by shaping the three peak voltage signals and three square wave signals with the same frequency. The signal processing module 5 determines the X-direction vibration acceleration component, the Y-direction vibration acceleration component, and the Z-direction vibration acceleration component based on the three peak voltage signals and three square wave signals with the same frequency input thereto. It then calculates the amplitude, azimuth angle, and frequency of the overall vibration acceleration sensed by the signal acquisition mechanism and transmits this to the wireless transmission module 6 for wireless transmission.

[0021] In this embodiment, each conventional cantilever beam piezoelectric device has a positive polarity output terminal and a negative polarity output terminal, each energy capture submodule has a positive input terminal, a negative input terminal, an output terminal, and a ground terminal, the multi-input flyback converter module 3 has a first input terminal, a second input terminal, a third input terminal, a power output terminal, and a ground terminal, each vibration sensor submodule has an input terminal, a peak output terminal, a square wave output terminal, a power input terminal, and a ground terminal, the signal processing module 5 has a first peak input terminal, a first square wave input terminal, a second peak input terminal, a second square wave input terminal, a third peak input terminal, a third wave input terminal, a data bus, a power input terminal, and a ground terminal, and the wireless transmission module 6 has a data bus, a power input terminal, and a ground terminal;The positive polarity output terminal of the conventional cantilever beam piezoelectric device PZTX in the X direction is connected to the positive input terminal of the energy capture submodule 2-X in the X direction, the negative polarity output terminal of the conventional cantilever beam piezoelectric device PZTX in the X direction is connected to the negative input terminal of the energy capture submodule 2-X in the X direction, the positive polarity output terminal of the conventional cantilever beam piezoelectric device PZTY in the Y direction is connected to the positive input terminal of the energy capture submodule 2-Y in the Y direction, the negative polarity output terminal of the conventional cantilever beam piezoelectric device PZTY in the Y direction is connected to the negative input terminal of the energy capture submodule 2-Y in the Y direction, the positive polarity output terminal of the conventional cantilever beam piezoelectric device PZTZ in the Z direction is connected to the positive input terminal of the energy capture submodule 2-Z in the Z direction, and the conventional cantilever beam piezoelectric device in the Z direction is connected to the positive polarity input terminal of the energy capture submodule 2-Z in the Z direction. The negative polarity output terminal of PZTZ is connected to the negative input terminal of the Z-direction energy capture submodule 2-Z, the positive polarity output terminal of the X-direction conventional cantilever beam piezoelectric device PZTX is connected to the X-direction vibration sensor submodule 4-X input terminal, the positive polarity output terminal of the Y-direction conventional cantilever beam piezoelectric device PZTY is connected to the Y-direction vibration sensor submodule 4-Y input terminal, the positive polarity output terminal of the Z-direction conventional cantilever beam piezoelectric device PZTZ is connected to the Z-direction vibration sensor submodule 4-Z input terminal, the output terminal of the X-direction energy capture submodule 2-X is connected to the first input terminal of the multi-input flyback converter module 3, the output terminal of the Y-direction energy capture submodule 2-Y is connected to the second input terminal of the multi-input flyback converter module 3, and the Z-direction energy The output end of the capture submodule 2-Z is connected to the third input end of the multi-input flyback converter module 3, the peak output end of the X-direction vibration sensing submodule 4-X is connected to the first peak input end of the signal processing module 5, the square wave output end of the X-direction vibration sensing submodule 4-X is connected to the first square wave input end of the signal processing module 5, the peak output end of the Y-direction vibration sensing submodule 4-Y is connected to the second peak input end of the signal processing module 5, the square wave output end of the Y-direction vibration sensing submodule 4-Y is connected to the second square wave input end of the signal processing module 5, the peak output end of the Z-direction vibration sensing submodule 4-Z is connected to the third peak input end of the signal processing module 5, the square wave output end of the Z-direction vibration sensing submodule 4-Z is connected to the first peak input end of the signal processing module 5, and the square wave output end of the Z-direction vibration sensing submodule 4-Z is connected to the second peak input end of the signal processing module 5. The third wave input terminal of the block 5 is connected, the data bus of the signal processing module 5 is connected to the data bus of the wireless transmission module 6, the power output terminal of the multi-input flyback converter module 3 is respectively connected to the power input terminal of the X-direction vibration sensing submodule 4-X, the power input terminal of the Y-direction vibration sensing submodule 4-Y / the power input terminal of the Z-direction vibration sensing submodule 4-Z, the power input terminal of the signal processing module 5, and the power input terminal of the wireless transmission module 6, the ground terminal of the multi-input flyback converter module 3, the ground terminal of the X-direction vibration sensing submodule 4-X, the ground terminal of the Y-direction vibration sensing submodule 4-Y, the ground terminal of the Z-direction vibration sensing submodule 4-Z, the ground terminal of the signal processing module 5, and the ground terminal of the wireless transmission module 6 are connected;The positive polarity output terminal and the negative polarity output terminal of the conventional cantilever beam piezoelectric device PZTX in the X direction are used to output a differential AC voltage V; PZTX+ and V PZTX－ The positive and negative output terminals of the conventional cantilever beam piezoelectric device PZTY in the Y direction are used to output a differential AC voltage V PZTY+ and V PZTY－ , the positive polarity output terminal and the negative polarity output terminal of the conventional cantilever beam piezoelectric device PZTZ in the Z direction are used to output a differential AC voltage V PZTZ+ and V PZTZ－ The output terminal of the X-direction energy capture submodule 2-X is used to output a first DC voltage, and the first DC voltage is recorded as V EHX The output terminal of the Y-direction energy capture submodule 2-Y is used to output a second DC voltage, and the second DC voltage is recorded as V EHY The output terminal of the Z-direction energy capture submodule 2-Z is used to output a third DC voltage, and the third DC voltage is recorded as V EHZ The peak output terminal of the X-direction vibration sensor module 4-X is used to output a peak voltage signal, which is recorded as V PEAKX The peak output terminal of the Y-direction vibration sensor module 4-Y is used to output a peak voltage signal, which is recorded as V PEAKY The peak output terminal of the Z-direction vibration sensor module 4-Z is used to output a peak voltage signal, which is recorded as V PEAKZ The square wave output terminal of the X-direction vibration sensor submodule 4-X is used to output a square wave signal of the same frequency, which is recorded as V FREQX The square wave output terminal of the Y-direction vibration sensor module 4-Y is used to output a square wave signal of the same frequency, and the square wave signal of the same frequency is recorded as V FREQY The square wave output terminal of the Z-direction vibration sensor module 4-Z is used to output a square wave signal of the same frequency, which is recorded as V FREQZ The signal processing module 5 pre-stores the amplitude-frequency characteristic curve of the conventional cantilever beam piezoelectric device and the timing period T (set according to actual use needs). The signal processing module 5 is based on the three peak voltage signals V input therein. PEAKX 、V PEAKY 、V PEAKZ And 3 channels of same frequency square wave signal V FREQX 、V FREQY 、V FREQZ , determine the X-direction vibration acceleration component a felt by the conventional cantilever beam piezoelectric device PZTX in the X direction X , Y direction vibration acceleration component a felt by conventional cantilever beam piezoelectric device PZTY Y The Z-direction vibration acceleration component a felt by the conventional cantilever beam piezoelectric device PZTZ in the Z directionZ , and then calculate the amplitude, direction angle and frequency of the overall vibration acceleration; the signal processing module 5 starts timing after it is powered on, and when the 3-way peak voltage signal V PEAKX 、V PEAKY 、V PEAKZ And 3 channels of same frequency square wave signal V FREQX 、V FREQY 、V FREQZ When inputted, the signal processing module 5 processes the 3 peak voltage signals V PEAKX 、V PEAKY 、V PEAKZ Continuous AD sampling is performed simultaneously, and the three channels of the same frequency square wave signal V are inputted. FREQX 、V FREQY 、V FREQZ Perform rising edge counting respectively. When sampling and timing reach a timing cycle T, stop counting and AD sampling, and perform mathematical processing on the sampling value and counting value obtained in the timing cycle, and then enter the next timing cycle to restart counting and sampling, and repeat the process. Among them, the specific process of mathematical processing on the sampling value and counting value obtained in the timing cycle at the end of each timing cycle T is as follows: the AD sampling frequency is recorded as F S , then within a timing period T, the signal processing module 5 processes the three peak voltage signals V PEAKX 、V PEAKY 、V PEAKZ Perform S AD samplings respectively, where S = F S *T, 3-way peak voltage signal V PEAKX 、V PEAKY 、V PEAKZ Each has S sampling data, and calculates the peak voltage signal V PEAKX The average value V of S sample data PEAKX-AVG 、V PEAKY The average value V of S sample data PEAKY-AVG and V PEAKZ The average value V of S sample data PEAKZ-AVG , determine V PEAKX-AVG 、V PEAKY-AVG and V PEAKZ-AVG The direction of the peak voltage signal corresponding to the maximum value is recorded as DIR, and DIR is one of X, Y, and Z. That is, the peak voltage signal output by the vibration sensor module in the DIR direction is the largest among the S sampling data obtained by AD sampling in a timing period T. The average value of the same frequency square wave signal V in a timing period T is recorded as FREQX The rising edge count value is recorded as N X , square wave signal with the same frequency V FREQY The rising edge count value is recorded as N Y , square wave signal with the same frequency VFREQZ The rising edge count value is recorded as N Z , the three-way square wave signal V FREQX 、V FREQY 、V FREQZ In the DIR direction, the rising edge count value of the square wave signal with the same frequency output by the vibration sensor module is retained and recorded as N. At this time, N=N DIR , N DIR N X 、N Y 、N Z One of them; the frequency of the overall vibration acceleration felt by the signal acquisition mechanism is recorded as F V , at this time there is F V =N DIR / T; Under the same vibration excitation conditions, the peak voltage signal V PEAKX The piezoelectric open circuit voltage is V PEAKX-POC , peak voltage signal V PEAKY The piezoelectric open circuit voltage is V PEAKY-POC , peak voltage signal V PEAKZ The piezoelectric open circuit voltage is V PEAKZ-POC , let V PEAKX-POC =0.5*k*V PEAKX-AVG 、V PEAKY-POC =0.5*k*V PEAKY-AVG 、V PEAKZ-POC =0.5*k*V PEAKZ-AVG , where k is the inverse of the voltage divider coefficient of the vibration sensor module; based on the three piezoelectric open circuit voltages V PEAKX-POC 、V PEAKY-POC 、V PEAKZ-POC and vibration frequency F V The amplitude-frequency characteristic curve of the conventional cantilever beam piezoelectric device is searched and queried to obtain the amplitude of the overall vibration acceleration in the X, Y and Z directions, where the amplitude of the vibration acceleration component in the X direction is a X , the amplitude of the vibration acceleration component in the Y direction a Y , the amplitude of the vibration acceleration component in the Z direction a Z , and calculate the amplitude of the overall vibration acceleration The direction angle of the overall vibration acceleration is the three angles between it and the X direction, Y direction, and Z direction, which are denoted as α, β, and γ respectively. α = arccos(a X / a)、β=arccos(a Y / a),γ=arccos(a Z / a).

[0022] like Figure 2As shown, in this embodiment, each energy capture submodule includes a first PMOS field effect transistor PM1, a second PMOS field effect transistor PM2, a first NMOS field effect transistor NM1, a second NMOS field effect transistor NM2, a first diode D1, a first capacitor C1, a first NPN transistor NP1 and a first PNP transistor PN1, the first capacitor C1 is a non-polarized capacitor, the source of the first PMOS field effect transistor PM1, the source of the second PMOS field effect transistor PM2, the anode of the first diode D1, the base of the first PNP transistor PN1 and the collector of the first NPN transistor NP1 are connected, the drain of the first PMOS field effect transistor PM1, the gate of the second PMOS field effect transistor PM2, the drain of the first NMOS field effect transistor NM1 and the gate of the second NMOS field effect transistor NM2 are connected, and the connection thereof The first terminal is the positive input terminal of the energy capture submodule, the gate of the first PMOS field effect transistor PM1, the drain of the second PMOS field effect transistor PM2, the gate of the first NMOS field effect transistor NM1, and the drain of the second NMOS field effect transistor NM2 are connected, and the connection end is the negative input terminal of the energy capture submodule, the cathode of the first diode D1, the collector of the first PNP transistor PN1 and one end of the first capacitor C1 are connected, the source of the first NMOS field effect transistor NM1, the source of the second NMOS field effect transistor NM2 and the other end of the first capacitor C1 are connected, and the connection end is the ground terminal of the energy capture submodule, the ground terminal of the energy capture submodule is grounded, the collector of the first PNP transistor PN1 and the base of the first NPN transistor NP1 are connected, and the emitter of the first NPN transistor NP1 is the output terminal of the energy capture submodule.

[0023] like Figure 3As shown, in this embodiment, the multi-input flyback converter module 3 includes a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a flyback transformer T, a first resistor R1, a second resistor R2, a second capacitor C2, a DC converter U1, a rechargeable lithium battery BAT1 and a linear regulator U2. The flyback transformer T includes a primary coil L1 and a secondary coil L2, and the turns ratio is 1. The second capacitor C2 is an electrolytic capacitor. The DC converter U1 has an input terminal, an output terminal, an enable terminal and a ground terminal. The linear regulator U2 has an input terminal, an output terminal and a ground terminal. The anode of the second diode D2 is the first input terminal of the multi-input flyback converter module 3, the anode of the third diode D3 is the second input terminal of the multi-input flyback converter module 3, the anode of the fourth diode D4 is the third input terminal of the multi-input flyback converter module 3, the cathode of the second diode D2, the cathode of the third diode D3, the cathode of the fourth diode D4 and the primary terminal of the flyback transformer T are connected to the flyback converter module 3. One end of the secondary coil L1 is connected, one end of the secondary coil L2 of the flyback transformer T is connected to the positive electrode of the fifth diode D5, the negative electrode of the fifth diode D5, the positive electrode of the second capacitor C2, one end of the first resistor R1 and the input end of the DC converter U1 are connected, the other end of the first resistor R1, one end of the second resistor R2 and the enable end of the DC converter U1 are connected, the output end of the DC converter U1, the positive electrode of the rechargeable lithium battery BAT1 and the input end of the linear regulator U2 are connected, and the linear regulator The output end of the device U2 is the power output end of the multi-input flyback converter module 3. The ground end of the DC converter U1, the negative electrode of the rechargeable lithium battery BAT1, the other end of the second resistor R2, the negative electrode of the second capacitor C2, the other end of the primary coil L1 of the flyback transformer T, the other end of the secondary coil L2 of the flyback transformer T and the ground end of the linear regulator U2 are connected, and their connection ends are the ground end of the multi-input flyback converter module 3. The ground end of the multi-input flyback converter module 3 is grounded.

[0024] like Figure 4As shown, in this embodiment, each vibration sensor submodule includes a third resistor R3, a fourth resistor R4, a fifth resistor R6, a sixth resistor R6, a seventh resistor R7, a sixth diode D6, a seventh diode D7, a first operational amplifier U3, a second operational amplifier U4, a comparator U5 and a third capacitor C3, the first operational amplifier U3 and the second operational amplifier U4 both have a non-inverting input terminal, an inverting input terminal, an output terminal, a power supply terminal and a ground terminal, the comparator U5 has a non-inverting input terminal, an inverting input terminal, an output terminal, a power supply terminal and a ground terminal, one end of the third resistor R3 is the input terminal of the vibration sensor submodule, the other end of the third resistor R3, one end of the fourth resistor R4, the non-inverting input terminal of the first operational amplifier U3 and the non-inverting input terminal of the comparator U5 are connected, the inverting input terminal of the first operational amplifier U3, the positive electrode of the sixth diode D6 and one end of the seventh resistor R7 are connected, the output terminal of the first operational amplifier U3, the negative electrode of the sixth diode D6 and the positive electrode of the seventh diode D7 are connected, the other end of the seventh resistor R7, the second operational amplifier U3 The inverting input of the amplifier U4 is connected to the output of the second operational amplifier U4, and its connection end is the peak output end of the vibration sensor submodule; the cathode of the seventh diode D7, the non-inverting input of the second operational amplifier U4 and one end of the third capacitor C3 are connected; one end of the fifth resistor R6, one end of the sixth resistor R6 and the inverting input of the comparator U5 are connected; the output end of the comparator U5 is the square wave output end of the vibration sensor submodule; the power supply end of the first operational amplifier U3, the power supply end of the second operational amplifier U4, the power supply end of the comparator U5 and the other end of the fifth resistor R6 are connected, and its connection end is the power input end of the vibration sensor module 4; the other end of the fourth resistor R4, the other end of the sixth resistor R6 and the other end of the third capacitor C3, the ground end of the first operational amplifier U3, the ground end of the second operational amplifier U4 and the ground end of the comparator U5 are connected, and their connection end is the ground end of the vibration sensor submodule; the ground end of the vibration sensor submodule is grounded, and the voltage dividing coefficient of the vibration sensor submodule is determined by its sixth resistor R6 and the seventh resistor R7.

Claims

1. An omnidirectional piezoelectric energy capture and vibration monitoring system, including a signal acquisition mechanism and an interface circuit, characterized in that The signal acquisition mechanism includes a support base and three conventional cantilever beam piezoelectric devices of the same specifications, the three conventional cantilever beam piezoelectric devices are respectively installed on the support base, and any two conventional cantilever beam piezoelectric devices are in a vertical state in space, the installation directions of the three conventional cantilever beam piezoelectric devices intersect at the geometric center of the support base, the geometric center of the support base is taken as the origin O, the installation directions of the three conventional cantilever beam piezoelectric devices are respectively used as the X direction, the Y direction and the Z direction to construct a spatial rectangular coordinate system XYZ, at this time, three mutually perpendicular planes are obtained, namely XOY, XOZ, and YOZ; the conventional cantilever beam piezoelectric device with the installation direction along the X direction is called It is a conventional cantilever beam piezoelectric device in the X direction. The conventional cantilever beam piezoelectric device with the installation direction along the Y direction is called the Y direction conventional cantilever beam piezoelectric device, and the conventional cantilever beam piezoelectric device with the installation direction along the Z direction is called the Z direction conventional cantilever beam piezoelectric device. The conventional cantilever beam piezoelectric device in the X direction is used to sense the vibration acceleration component in the X direction and convert it into a corresponding differential AC voltage output. The conventional cantilever beam piezoelectric device in the Y direction is used to sense the vibration acceleration component in the Y direction and convert it into a corresponding differential AC voltage output. The conventional cantilever beam piezoelectric device in the Z direction is used to sense the vibration acceleration component in the Z direction and convert it into a corresponding differential AC voltage output. The interface circuit includes an energy capture module, a vibration sensing module, a multi-input flyback converter module, a signal processing module and a wireless transmission module. The energy capture module includes three identical energy capture submodules, which are respectively referred to as the X-direction energy capture submodule, the Y-direction energy capture submodule and the Z-direction energy capture submodule. The X-direction energy capture submodule is used to access the differential AC voltage output by the conventional cantilever beam piezoelectric device in the X direction and convert the differential AC voltage into a first DC voltage and output it to the multi-input flyback converter module. The Y-direction energy capture submodule is used to access the conventional cantilever beam piezoelectric device in the Y direction. The Z-direction energy capture submodule is used to receive the differential AC voltage output by the Z-direction conventional cantilever beam piezoelectric device and convert the differential AC voltage into a second DC voltage and output it to the multi-input flyback converter module; the Z-direction energy capture submodule is used to receive the differential AC voltage output by the Z-direction conventional cantilever beam piezoelectric device and convert the differential AC voltage into a third DC voltage and output it to the multi-input flyback converter module; the multi-input flyback converter module performs DC conversion, linear voltage regulation, and electrical energy storage on the first DC voltage, the second DC voltage, and the third DC voltage input therein, and simultaneously provides a working power supply voltage for the vibration sensing module, the signal processing module, and the wireless transmitting module; The vibration sensing module includes three vibration sensing submodules with the same structure, which are respectively called X-direction vibration sensing submodule, Y-direction vibration sensing submodule and Z-direction vibration sensing submodule. The X-direction vibration sensing submodule senses the differential AC voltage output by the conventional cantilever beam piezoelectric device in the X direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and performs shaping triggering to generate a square wave signal of the same frequency and output it to the signal processing module. The Y-direction vibration sensing submodule senses the differential AC voltage output by the conventional cantilever beam piezoelectric device in the Y direction and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and performs shaping triggering to generate a square wave signal of the same frequency and output it to the signal processing module. Generate a same-frequency square wave signal and output it to the signal processing module. The Z-direction vibration sensor submodule senses the differential AC voltage output by the Z-direction conventional cantilever beam piezoelectric device and performs peak tracking on the sensed differential AC voltage to generate a peak voltage signal and performs shaping triggering to generate a same-frequency square wave signal and output it to the signal processing module. The signal processing module determines the X-direction vibration acceleration component, the Y-direction vibration acceleration component, and the Z-direction vibration acceleration component based on the three peak voltage signals and three same-frequency square wave signals input therein, and then calculates the amplitude, direction angle, and frequency of the overall vibration acceleration felt by the signal acquisition mechanism, and transmits them to the wireless transmission module for wireless transmission.

2. The omnidirectional piezoelectric energy capture and vibration monitoring system according to claim 1, characterized in that Each of the conventional cantilever beam piezoelectric devices has a positive polarity output terminal and a negative polarity output terminal, each of the energy capture submodules has a positive input terminal, a negative input terminal, an output terminal and a ground terminal, the multi-input flyback converter module has a first input terminal, a second input terminal, a third input terminal, a power output terminal and a ground terminal, each of the vibration sensor submodules has an input terminal, a peak output terminal, a square wave output terminal, a power input terminal and a ground terminal, the signal processing module has a first peak input terminal, a first square wave input terminal, a second peak input terminal, a second square wave input terminal, a third peak input terminal, a third square wave input terminal, a data bus, a power input terminal and a ground terminal, the wireless transmission module has a data bus, The power input terminal and the ground terminal; the positive polarity output terminal of the conventional cantilever beam piezoelectric device in the X direction is connected to the positive input terminal of the energy capture submodule in the X direction, the negative polarity output terminal of the conventional cantilever beam piezoelectric device in the X direction is connected to the negative input terminal of the energy capture submodule in the X direction, the positive polarity output terminal of the conventional cantilever beam piezoelectric device in the Y direction is connected to the positive input terminal of the energy capture submodule in the Y direction, the negative polarity output terminal of the conventional cantilever beam piezoelectric device in the Y direction is connected to the negative input terminal of the energy capture submodule in the Y direction, the positive polarity output terminal of the conventional cantilever beam piezoelectric device in the Z direction is connected to the positive input terminal of the energy capture submodule in the Z direction, and the positive polarity output terminal of the conventional cantilever beam piezoelectric device in the Z direction is connected to the positive input terminal of the energy capture submodule in the Z direction. The negative polarity output end of the conventional cantilever beam piezoelectric device is connected to the negative input end of the Z-direction energy capture submodule, the positive polarity output end of the conventional cantilever beam piezoelectric device in the X-direction is connected to the input end of the X-direction vibration sensor submodule, the positive polarity output end of the conventional cantilever beam piezoelectric device in the Y-direction is connected to the input end of the Y-direction vibration sensor submodule, the positive polarity output end of the conventional cantilever beam piezoelectric device in the Z-direction is connected to the input end of the Z-direction vibration sensor submodule, the output end of the X-direction energy capture submodule is connected to the first input end of the multi-input flyback converter module, and the output end of the Y-direction energy capture submodule is connected to the second input end of the multi-input flyback converter module. The output end of the Z-direction energy capture submodule is connected to the third input end of the multi-input flyback converter module, the peak output end of the X-direction vibration sensor submodule is connected to the first peak input end of the signal processing module, the square wave output end of the X-direction vibration sensor submodule is connected to the first square wave input end of the signal processing module, the peak output end of the Y-direction vibration sensor submodule is connected to the second peak input end of the signal processing module, the square wave output end of the Y-direction vibration sensor submodule is connected to the second square wave input end of the signal processing module, and the peak output end of the Z-direction vibration sensor submodule is connected to the third peak input end of the signal processing module.The square wave output of the Z-direction vibration sensor submodule is connected to the third square wave input of the signal processing module. The data bus of the signal processing module is connected to the data bus of the wireless transmitter module. The power output of the multi-input flyback converter module is respectively connected to the power input of the X-direction vibration sensor submodule, the power input of the Y-direction vibration sensor submodule / the power input of the Z-direction vibration sensor submodule, the power input of the signal processing module, and the power input of the wireless transmitter module. The ground of the multi-input flyback converter module, the ground of the X-direction vibration sensor submodule, the ground of the Y-direction vibration sensor submodule, the ground of the Z-direction vibration sensor submodule, the ground of the signal processing module, and the ground of the wireless transmitter module are connected. The positive and negative output terminals of the conventional cantilever beam piezoelectric device in the X-direction are used to output a differential AC voltage V. PZTX+ and V PZTX－ The positive polarity output terminal and the negative polarity output terminal of the conventional cantilever beam piezoelectric device in the Y direction are used to output a differential AC voltage V PZTY+ and V PZTY－ The positive polarity output terminal and the negative polarity output terminal of the conventional cantilever beam piezoelectric device in the Z direction are used to output a differential AC voltage V PZTZ+ and V PZTZ－ The output terminal of the X-direction energy capture submodule is used to output a first DC voltage, and the first DC voltage is recorded as V EHX The output terminal of the Y-direction energy capture submodule is used to output a second DC voltage, and the second DC voltage is recorded as V EHY The output terminal of the Z-direction energy capture submodule is used to output a third DC voltage, and the third DC voltage is recorded as V EHZ The peak output terminal of the X-direction vibration sensor module is used to output a peak voltage signal, which is recorded as V PEAKX The peak output terminal of the Y-direction vibration sensor module is used to output a peak voltage signal, which is recorded as V PEAKY The peak output terminal of the Z-direction vibration sensor module is used to output a peak voltage signal, which is recorded as V PEAKZ The square wave output terminal of the X-direction vibration sensor module is used to output a square wave signal of the same frequency, and the square wave signal of the same frequency is recorded as V FREQX The square wave output terminal of the Y-direction vibration sensor module is used to output a square wave signal of the same frequency, and the square wave signal of the same frequency is recorded as V FREQY The square wave output terminal of the Z-direction vibration sensor module is used to output a square wave signal of the same frequency, and the square wave signal of the same frequency is recorded as V FREQZ The signal processing module pre-stores the amplitude-frequency characteristic curve and timing period T of the conventional cantilever beam piezoelectric device. The signal processing module is based on the three peak voltage signals V input therein. PEAKX 、V PEAKY 、V PEAKZ And 3 channels of same frequency square wave signal V FREQX 、V FREQY 、V FREQZ , determine the X-direction vibration acceleration component a felt by the conventional cantilever beam piezoelectric device in the X direction X , Y direction vibration acceleration component a felt by conventional cantilever beam piezoelectric device in Y direction Y The Z-direction vibration acceleration component a felt by the conventional cantilever beam piezoelectric device in the Z direction Z , and then calculate the amplitude, direction angle and frequency of the overall vibration acceleration; the signal processing module starts timing after power is turned on, and when the three peak voltage signals V PEAKX 、V PEAKY 、V PEAKZ And 3 channels of same frequency square wave signal V FREQX 、V FREQY 、V FREQZ When inputted into it, the signal processing module processes the 3-way peak voltage signal V PEAKX 、V PEAKY 、V PEAKZ Continuous AD sampling is performed simultaneously, and the three channels of the same frequency square wave signal V are inputted. FREQX 、V FREQY 、V FREQZ Perform rising edge counting respectively. When sampling and timing reach a timing cycle T, stop counting and AD sampling, and perform mathematical processing on the sampling value and counting value obtained in the timing cycle, and then enter the next timing cycle to restart counting and sampling, and repeat the process. Among them, the specific process of mathematical processing on the sampling value and counting value obtained in the timing cycle at the end of each timing cycle T is as follows: the AD sampling frequency is recorded as F S , then the signal processing module in a timing period T processes the three peak voltage signals V PEAKX 、V PEAKY 、V PEAKZ Perform S AD samplings respectively, where S = F S *T, 3-way peak voltage signal V PEAKX 、V PEAKY 、V PEAKZ Each has S sampling data, and calculates the peak voltage signal V PEAKX The average value V of S sample data PEAKX-AVG 、V PEAKY The average value V of S sample data PEAKY-AVG and V PEAKZ The average value V of S sample data PEAKZ-AVG , determine V PEAKX-AVG 、V PEAKY-AVG and V PEAKZ-AVG The direction of the peak voltage signal corresponding to the maximum value is recorded as DIR, and DIR is one of X, Y, and Z. That is, the peak voltage signal output by the vibration sensor module in the DIR direction is the largest among the S sampling data obtained by AD sampling in a timing period T. The average value of the same frequency square wave signal V in a timing period T is recorded as FREQX The rising edge count value is recorded as N X , square wave signal with the same frequency V FREQY The rising edge count value is recorded as N Y , square wave signal with the same frequency V FREQZ The rising edge count value is recorded as N Z , the three-way square wave signal V FREQX 、V FREQY 、V FREQZ In the DIR direction, the rising edge count value of the square wave signal with the same frequency output by the vibration sensor module is retained and recorded as N. At this time, N=N DIR , N DIR N X 、N Y 、N Z The frequency of the overall vibration acceleration sensed by the signal acquisition mechanism is recorded as F V , at this time there is F V =N DIR / T; Under the same vibration excitation conditions, the peak voltage signal V PEAKX The piezoelectric open circuit voltage is V PEAKX-POC , peak voltage signal V PEAKY The piezoelectric open circuit voltage is V PEAKY-POC , peak voltage signal V PEAKZ The piezoelectric open circuit voltage is V PEAKZ-POC , let V PEAKX-POC =0.5*k*V PEAKX-AVG 、V PEAKY-POC =0.5*k*V PEAKY-AVG 、V PEAKZ-POC =0.5*k*V PEAKZ-AVG , where k is the inverse of the voltage divider coefficient of the vibration sensor module; based on the three piezoelectric open circuit voltages V PEAKX-POC 、V PEAKY-POC 、V PEAKZ-POC and vibration frequency F V The amplitude-frequency characteristic curve of the conventional cantilever beam piezoelectric device is searched and queried to obtain the amplitude of the overall vibration acceleration in the X, Y and Z directions, where the amplitude of the vibration acceleration component in the X direction is a X , the amplitude of the vibration acceleration component in the Y direction a Y , the amplitude of the vibration acceleration component in the Z direction a Z , and calculate the amplitude of the overall vibration acceleration The direction angle of the overall vibration acceleration is the three angles between it and the X direction, Y direction, and Z direction, which are denoted as α, β, and γ respectively. α=arccos(a X / a)、β=arccos(a Y / a),γ=arccos(a Z / a).

3. The omnidirectional piezoelectric energy capture and vibration monitoring system according to claim 2, characterized in that Each of the energy capture submodules includes a first PMOS field effect transistor, a second PMOS field effect transistor, a first NMOS field effect transistor, a second NMOS field effect transistor, a first diode, a first capacitor, a first NPN transistor and a first PNP transistor. The first capacitor is a non-polarized capacitor. The source of the first PMOS field effect transistor, the source of the second PMOS field effect transistor, the positive electrode of the first diode, the base of the first PNP transistor and the collector of the first NPN transistor are connected. The drain of the first PMOS field effect transistor, the gate of the second PMOS field effect transistor, the drain of the first NMOS field effect transistor and the gate of the second NMOS field effect transistor are connected, and their connection end is the positive input end of the energy capture submodule. The gate of the first PMOS field effect transistor, the drain of the second PMOS field effect transistor, the gate of the first NMOS field effect transistor, and the drain of the second NMOS field effect transistor are connected, and their connection end is the negative input end of the energy capture submodule, the cathode of the first diode, the collector of the first PNP transistor and one end of the first capacitor are connected, the source of the first NMOS field effect transistor, the source of the second NMOS field effect transistor and the other end of the first capacitor are connected and their connection end is the ground end of the energy capture submodule, the ground end of the energy capture submodule is grounded, the collector of the first PNP transistor and the base of the first NPN transistor are connected, and the emitter of the first NPN transistor is the output end of the energy capture submodule.

4. The omnidirectional piezoelectric energy capture and vibration monitoring system according to claim 2, characterized in that The multi-input flyback converter module includes a second diode, a third diode, a fourth diode, a fifth diode, a flyback transformer, a first resistor, a second resistor, a second capacitor, a DC converter, a rechargeable lithium battery and a linear regulator. The flyback transformer includes a primary coil and a secondary coil, and the turns ratio is 1. The second capacitor is an electrolytic capacitor. The DC converter has an input terminal, an output terminal, an enable terminal and a ground terminal. The linear regulator has an input terminal, an output terminal and a ground terminal. The anode of the second diode is the first input terminal of the multi-input flyback converter module, the anode of the third diode is the second input terminal of the multi-input flyback converter module, and the anode of the fourth diode is the third input terminal of the multi-input flyback converter module. The cathode of the second diode, the cathode of the third diode, and the cathode of the fourth diode are connected to one end of the primary coil of the flyback transformer. One end of the secondary coil of the flyback transformer is connected to the positive electrode of the fifth diode, the negative electrode of the fifth diode, the positive electrode of the second capacitor, one end of the first resistor and the input end of the DC converter are connected, the other end of the first resistor and one end of the second resistor are connected to the enable end of the DC converter, the output end of the DC converter, the positive electrode of the rechargeable lithium battery and the input end of the linear regulator are connected, the output end of the linear regulator is the power output end of the multi-input flyback converter module, the ground end of the DC converter, the negative electrode of the rechargeable lithium battery, the other end of the second resistor, the negative electrode of the second capacitor, the other end of the primary coil of the flyback transformer, the other end of the secondary coil of the flyback transformer and the ground end of the linear regulator are connected and their connection ends are the ground end of the multi-input flyback converter module, and the ground end of the multi-input flyback converter module is grounded.

5. The omnidirectional piezoelectric energy capture and vibration monitoring system according to claim 2, characterized in that Each of the vibration sensor submodules includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a sixth diode, a seventh diode, a first operational amplifier, a second operational amplifier, a comparator and a third capacitor. The first operational amplifier and the second operational amplifier both have a non-inverting input terminal, an inverting input terminal, an output terminal, a power supply terminal and a ground terminal. The comparator has a non-inverting input terminal, an inverting input terminal, an output terminal, a power supply terminal and a ground terminal. One end of the third resistor is the input terminal of the vibration sensor submodule, the other end of the third resistor, one end of the fourth resistor, the non-inverting input terminal of the first operational amplifier and the non-inverting input terminal of the comparator are connected, the inverting input terminal of the first operational amplifier, the positive electrode of the sixth diode and one end of the seventh resistor are connected, the output terminal of the first operational amplifier, the negative electrode of the sixth diode and the positive electrode of the seventh diode are connected, the other end of the seventh resistor, the inverting input terminal of the second operational amplifier The phase input end is connected to the output end of the second operational amplifier and its connection end is the peak output end of the vibration sensor submodule, the cathode of the seventh diode, the non-inverting input end of the second operational amplifier and one end of the third capacitor are connected, one end of the fifth resistor and one end of the sixth resistor are connected to the inverting input end of the comparator, the output end of the comparator is the square wave output end of the vibration sensor submodule, the power supply end of the first operational amplifier, the power supply end of the second operational amplifier, the power supply end of the comparator and the other end of the fifth resistor are connected and the connection end is the power input end of the vibration sensor module, the other end of the fourth resistor, the other end of the sixth resistor and the other end of the third capacitor, the ground end of the first operational amplifier, the ground end of the second operational amplifier and the ground end of the comparator are connected and the connection end is the ground end of the vibration sensor submodule, and the ground end of the vibration sensor submodule is grounded.

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