A piezoelectric vibration energy recovery and battery management system for industrial water pumps

Abstract

This invention discloses a piezoelectric vibration energy recovery and battery management system for industrial water pumps, in the field of sensor network power supply and vibration energy recovery technology. It supplies power to vibration sensors and includes a piezoelectric transducer for converting water pump vibration energy into electrical energy; an energy management circuit for temporarily storing electrical energy in a pre-stage energy storage capacitor and transferring the stored energy to a post-stage supercapacitor; and a dual-power switching circuit for controlling the connection between the post-stage supercapacitor and the main battery to power the vibration sensor based on the voltage state of the post-stage supercapacitor. The pre-stage capacitor matches the high internal resistance of the piezoelectric transducer, ensuring high-frequency hiccup startup of the undervoltage lockout module. The post-stage supercapacitor matches the low impedance heavy-load characteristics of the sensor, avoiding power supply failure due to severe impedance mismatch when a microwatt-level high-internal-resistance energy source directly faces a hundred-milliwatt-level low-impedance pulse load.

Description

Technical Field

[0001] This invention relates to the field of sensor network power supply and vibration energy recovery, specifically to a piezoelectric vibration energy recovery and battery management system for industrial water pumps. Background Technology

[0002] Traditional battery-powered wireless vibration sensors used for monitoring the status of water pumps in chemical plants generally suffer from limited lifespan, difficulty in replacement and maintenance in flammable and explosive industrial environments, and high operation and maintenance costs. Their main power supply is usually a 3.6V lithium thionyl chloride battery. The sensor is normally in a microampere-level dormant state, but it will generate a peak current surge of 100mA during wireless data transmission. This pulsed heavy-load discharge can easily damage the internal chemical properties of the battery, leading to premature aging and failure.

[0003] Environmental vibration energy recovery technology can convert the mechanical vibrations of industrial equipment into electrical energy to provide auxiliary power for vibration sensors, and is a core solution to address the aforementioned pain points. However, existing piezoelectric vibration energy recovery solutions still have significant gaps in engineering applications: First, most solutions are designed for mid-to-high frequency vibration scenarios above 60Hz and high acceleration vibration scenarios above 1g, while the vibration frequency of chemical plant water pumps is mostly concentrated around 25Hz, with an effective vibration acceleration of only 1.5m / s². 2 First, existing solutions struggle to achieve efficient resonant matching. Second, they lack micro-energy management and battery scheduling strategies adapted to all operating conditions of industrial sensors, making it easy for the microampere-level current from piezoelectric output to overload heavily driven systems to fail. Third, existing dual-power-switching solutions (such as simply using parallel diodes) lack robust anti-backflow and hardware interlocking mechanisms, easily leading to system jitter or main battery leakage current loss under pulsed loads. Therefore, it is necessary to design a piezoelectric vibration energy recovery and battery management system for industrial water pumps to address these technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a piezoelectric vibration energy recovery and battery management system for industrial water pumps, which solves the problems of low piezoelectric energy recovery efficiency, inability of weak energy to directly drive pulse loads, and leakage and vibration during dual power supply switching in the prior art under low frequency and low acceleration conditions.

[0005] The present invention achieves the above objectives through the following technical solutions: A piezoelectric vibration energy recovery and battery management system for industrial water pumps, used to power vibration sensors, includes: A piezoelectric transducer used to convert the vibration energy of an industrial water pump into alternating current. Energy management circuits used to convert AC power into DC power and transport DC power; A front-stage energy storage capacitor used to temporarily store DC power; The supercapacitor is used to store the DC energy temporarily stored in the preceding energy storage capacitor. The main battery used to provide backup power; A dual power supply switching circuit that is connected to the downstream supercapacitor and the main battery respectively; The dual power supply switching circuit includes a hysteresis comparator module and a logic inverting module connected to the output of the hysteresis comparator module. The hysteresis comparator module is used to compare the voltage state of the subsequent supercapacitor with a preset hysteresis threshold window and output a corresponding control signal. The logic inverting module is used to respond to the control signal to control the subsequent supercapacitor and the main battery to selectively connect to the vibration sensor for power supply.

[0006] As a further optimization of the invention, the dual power supply switching circuit also includes a voltage detection module, a first switch, and a second switch; The voltage detection module is used to sample the voltage state of the subsequent supercapacitor; The first switch is connected in series in the power supply circuit between the downstream supercapacitor and the vibration sensor; the second switch is connected in series in the power supply circuit between the main battery and the vibration sensor.

[0007] As a further optimization of the invention, the signal input terminal of the hysteresis comparator module is connected to the output terminal of the voltage detection module, the signal output terminal of the hysteresis comparator module is directly connected to the control terminal of the first switch, and the signal output terminal of the hysteresis comparator module is connected to the control terminal of the second switch via the logic inverting module.

[0008] As a further optimization of the invention, the preset hysteresis threshold window is defined by a falling threshold and a rising threshold; The drop threshold is set to be higher than the minimum safe operating voltage of the vibration sensor, and the rise threshold is set to be lower than the rated voltage of the main battery.

[0009] As a further optimization of the invention, the energy management circuit integrates a rectifier module, an undervoltage lockout module, and a voltage conversion module. The undervoltage lockout module is configured to monitor the terminal voltage of the front-stage energy storage capacitor. The input terminal of the rectifier module constitutes the input terminal of the energy management circuit, the output terminal of the rectifier module is connected to the input terminal of the undervoltage lockout module, the output terminal of the undervoltage lockout module is connected to the input terminal of the voltage conversion module, and the output terminal of the voltage conversion module constitutes the output terminal of the energy management circuit.

[0010] As a further optimization of the invention, the piezoelectric transducer includes a cantilever beam fixed at one end and a nonlinear magnetic repulsion broadband flexible anti-vibration structure; the cantilever beam has a first-order natural frequency, and the anti-vibration structure is used to broaden the resonant frequency band, so that the system forms a wide resonant frequency band including the first-order natural frequency, and provides non-contact magnetic repulsion flexible limiting when the vibration amplitude of the cantilever beam exceeds a preset threshold. The fixed end of the cantilever beam is located on one side of the base, and the free end of the cantilever beam is provided with a counterweight mass block. The shock-resistant structure includes an upper fixed bracket and a lower fixed bracket fixed on both sides of the base, a static magnet at the free end of the upper fixed bracket and the lower fixed bracket, and a moving magnet on the upper and lower surfaces of the counterweight block, respectively. The static magnet and the moving magnet have the same magnetic poles facing each other.

[0011] As a further optimization of the invention, the cantilever beam is composed of an elastic metal substrate and piezoelectric ceramic layers attached to the upper and lower surfaces of the elastic metal substrate.

[0012] As a further optimization of the invention, the elastic metal substrate is a 301 elastic steel substrate, the piezoelectric ceramic layer is a PZT-5H piezoelectric ceramic sheet, and the upper and lower PZT-5H piezoelectric ceramic sheets form a series electrical structure.

[0013] As a further optimization of the invention, the vibration frequency of the industrial water pump is in the range of 24Hz to 26Hz, the first-order natural frequency is 24.5Hz to 25.5Hz, and the wide-range resonant frequency band is 24Hz to 26Hz.

[0014] As a further optimization of the invention, the front-stage energy storage capacitor is a ceramic capacitor with a capacitance value between 5μF and 20μF, and the rear-stage supercapacitor is a farad capacitor with a capacitance value between 0.2F and 1F.

[0015] The beneficial effects of this invention are as follows: 1) This invention constructs an asymmetric dual-capacitor decoupling architecture, which adopts a front-stage microfarad-level temporary storage and a rear-stage farad-level energy storage architecture. The front-stage capacitor matches the high internal resistance characteristics of the piezoelectric transducer to ensure the high-frequency hiccup start of the undervoltage lockout module; the rear-stage supercapacitor matches the low impedance heavy-load characteristics of the sensor, realizing physical isolation and impedance decoupling between the microwatt-level energy source and the hundreds of milliwatt-level pulse load, and solving the technical bottleneck of energy transmission failure when weak current is directly connected to a large load. 2) The nonlinear magnetic repulsion broadband flexible shockproof fracture structure of the present invention introduces a repulsive magnetic pole structure at the free end of the cantilever beam. On the one hand, by utilizing the nonlinear hardening stiffness brought about by the magnetic repulsion force, the resonant frequency band of the system is effectively broadened from a sharp single point to 24Hz~26Hz, realizing adaptive broadband collection under the variable operating conditions of the water pump and avoiding detuning and termination. On the other hand, the repulsive magnetic force acts as a non-contact flexible buffer limiter under extreme amplitude, completely solving the engineering pain point of mechanical fracture of PZT-5H piezoelectric wafer caused by the huge impact of water pump start-up and shutdown. 3) This invention, through an energy management circuit with an undervoltage lockout module, in conjunction with a pre-stage energy storage capacitor, utilizes a charging-wake-discharging-sleep cycle mode to transfer piezoelectric charge to the subsequent stage under no-load pressure conditions, successfully achieving efficient trickle collection of microampere-level piezoelectric weak sources and realizing efficient trickle collection of micro-energy. 4) This invention achieves anti-shake and hardware interlocking through dual power supply switching logic. The hysteresis comparator module completely eliminates the power switching jitter problem caused by voltage drop during heavy load. At the same time, the logic inversion module constructs a hardware dead-zone interlocking mechanism between the first switch and the second switch. When the supercapacitor is powered, the second switch is physically disconnected, completely cutting off the static leakage current return path of the main battery, realizing the true zero-power sleep of the main battery, and greatly extending the service life of the sensor. 5) This invention takes into account the 1.5 m / s water pump speed of a chemical plant. 2 Under extremely low acceleration conditions, the piezoelectric output current is extremely weak. If a standard capacitance value is used, its charging speed will be much slower than the chip's static power consumption, and the chip will never be able to wake up. Therefore, a large capacitance value of 5μF to 20μF is used as a pre-stage temporary storage. Combined with the stable wide-band output brought by the nonlinear magnetic repulsion structure, it is ensured that the undervoltage lockout module can still stably "hiccup" and start up under extremely weak sources, which improves the overall energy harvesting efficiency by several times and avoids the fact that the standard capacitor of the micro energy management chip cannot be adapted to the actual application scenario. 6) The nonlinear magnetic repulsion structure of this invention ensures stable energy output of the water pump in the entire operating frequency band of 24Hz to 26Hz from the mechanical layer source; the asymmetric dual-capacitor architecture realizes physical isolation and impedance decoupling of weak energy and pulse heavy load in the energy storage layer; the pure hardware hysteresis anti-interlock circuit realizes zero static leakage sleep of the main battery in the power supply layer; the three work together from the bottom up, so that the system is powered by environmental vibration when the water pump is running normally, and the main battery will only intervene in the extreme case of continuous water pump shutdown. The theoretical service life can reach more than 10 years, which completely solves the problem of replacing batteries of wireless sensors in industrial fields. Attached Figure Description

[0016] Figure 1 This is a block diagram of the overall system structure and control logic of the present invention; Figure 2This is a schematic diagram of the bicrystalline cantilever beam structure of the piezoelectric transducer of the present invention; Figure 3 This is a partial control connection diagram of the dual power supply switching circuit of the present invention; Figure 4 This is a waveform diagram of the intermittent charging and discharging voltage of the front-end energy storage capacitor under 25Hz vibration conditions. Figure 5 The waveform diagram shows the system-level energy scheduling and battery charge consumption verification of this invention during a complete 600-second operating cycle. In the diagram: 10. Piezoelectric transducer; 11. Base; 12. Elastic metal substrate; 13. Piezoelectric ceramic layer; 14. Counterweight block; 15. Upper fixed bracket; 16. Lower fixed bracket; 17. Static magnet; 18. Moving magnet; U1. Energy management circuit; U11. Rectifier module; U12. Undervoltage lockout module; U13. Buck module; C1. Pre-stage energy storage capacitor; 20. Dual power supply switching circuit; 21. Voltage detection module; C2. Post-stage supercapacitor; B1. Main battery; K1. First switch; K2. Second switch; U2. Hysteresis comparator module; U3. Logic inverting module; 30. Wireless vibration sensor. Detailed Implementation

[0017] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0018] Example like Figure 1 and Figure 2 As shown, this embodiment relates to a piezoelectric vibration energy recovery and battery management system for industrial water pumps. The system includes a piezoelectric transducer 10, a pre-stage energy storage capacitor C1, an energy management circuit U1, a main battery B1, a post-stage supercapacitor C2, and a dual-power switching circuit 20. The energy management circuit U1 has a rectifier module U11. The output terminal of the piezoelectric transducer 10 is connected to the AC input terminal of the rectifier module U11 in the energy management circuit U1, and the pre-stage energy storage capacitor C1 is connected between the DC output terminal of the rectifier module U11 and ground for temporary energy storage. The system collects the vibration energy of the industrial water pump through the piezoelectric transducer 10 and converts the vibration energy into electrical energy. The dual-power switching circuit 20, in conjunction with the main battery B1 and the post-stage supercapacitor C2, charges the vibration sensor.

[0019] The dual-power switching circuit 20 has two input terminals and one output terminal. The two input terminals of the dual-power switching circuit 20 are connected to the main battery B1 and the subsequent supercapacitor C2, respectively, and its output terminal is connected to the vibration sensor. In this embodiment, the vibration sensor is a wireless vibration sensor 30. In other embodiments, this system can also be applied to a wired vibration sensor. The main battery B1 and the subsequent supercapacitor C2 are the two power sources for the wireless vibration sensor 30, and the dual-power switching circuit 20 is used to detect the voltage of the subsequent supercapacitor C2 and switch the power supply.

[0020] The energy management circuit U1 consists of a rectifier module U11, an undervoltage lockout module U12, and a buck module U13. The front-end energy storage capacitor C1 is preferably a 10μF ceramic capacitor, the main battery B1 is preferably a lithium thionyl chloride battery with a rated voltage of 3.6V, and the rear-end supercapacitor C2 is preferably a 0.47F farad capacitor. The piezoelectric transducer 10 is the piezoelectric energy harvesting device. The rectifier module U11 is preferably a full-bridge rectifier, and the buck module U13 is preferably a synchronous buck converter.

[0021] During operation, the piezoelectric transducer 10 converts the vibration energy of the industrial water pump into microampere-level alternating current based on the piezoelectric effect. This alternating current first enters the rectifier module U11 inside the energy management circuit U1, and after rectification, outputs direct current (DC) energy. This DC energy flows into the pre-stage energy storage capacitor C1 for temporary storage. When the energy management circuit U1 is in sleep mode, the pre-stage energy storage capacitor C1 stores energy. When the voltage of the pre-stage energy storage capacitor C1 rises to the wake-up threshold, the energy management circuit U1 enters wake-up mode and transfers the energy from the pre-stage energy storage capacitor C1 to the subsequent supercapacitor C2. When the voltage of the pre-stage energy storage capacitor C1 drops to the turn-off threshold, the energy management circuit U1 returns to sleep mode, and the pre-stage energy storage capacitor C1 continues to store energy. When the voltage of the supercapacitor C2 rises to the rising threshold, the dual power supply switching circuit 20 supplies power to the wireless vibration sensor 30 through the supercapacitor C2; when the voltage of the supercapacitor C2 drops to the falling threshold, the dual power supply switching circuit 20 supplies power to the wireless vibration sensor 30 through the main battery B1.

[0022] The dual-power switching circuit 20 includes a voltage detection module 21, a first switch K1 connected to the main battery B1, and a second switch K2 connected to the subsequent supercapacitor C2. The voltage detection module 21 is connected to a hysteresis comparator module U2. The first switch K1 is connected to the hysteresis comparator module U2, and the hysteresis comparator module U2 is connected to the second switch K2 via a logic inverting module U3. Specifically, the input terminal of the voltage detection module 21 is connected to the positive terminal of the subsequent supercapacitor C2 to collect the terminal voltage, and the signal output terminal of the voltage detection module 21 is connected to the signal input terminal of the hysteresis comparator module U2. The hysteresis comparator module U2 has a built-in reference voltage reference and is equipped with a falling threshold and a rising threshold to trigger the operation of the dual-power switching circuit 20. The reference voltage reference is a preset hysteresis threshold window, which is defined by the falling threshold and the rising threshold. The falling threshold is higher than the minimum safe operating voltage of the wireless vibration sensor 30, and the rising threshold is lower than the rated voltage of the main battery B1.

[0023] The signal output of the hysteresis comparator module U2 is directly connected to the control terminal of the first switch K1, and simultaneously, the signal output of the hysteresis comparator module U2 is connected to the input terminal of the logic inverting module U3. The output terminal of the logic inverting module U3 is connected to the control terminal of the second switch K2. The first switch K1 is connected in series in the power supply circuit between the downstream supercapacitor C2 and the wireless vibration sensor 30, and the second switch K2 is connected in series in the power supply circuit between the main battery B1 and the wireless vibration sensor 30.

[0024] During the power supply process of the wireless vibration sensor 30, the voltage detection module 21 samples the voltage of the downstream supercapacitor C2. The hysteresis comparator module U2, based on the sampling result from the voltage detection module 21, and in conjunction with the logic inverting module U3, controls the first switch K1 and the second switch K2. The hysteresis comparator module U2 outputs a control signal to control the first switch K1, and the logic inverting module U3 responds to the control signal, generating an inverted signal to control the second switch K1. When the voltage of the downstream supercapacitor C2 rises to the rising threshold, the first switch K1 opens and the second switch K2 closes; when the voltage of the downstream supercapacitor C2 drops to the falling threshold, the first switch K1 closes and the second switch K2 opens. This allows the dual-power switching circuit 20 to seamlessly switch between supplying power to the wireless vibration sensor 30 via hardware interlocking logic, based on the voltage state of the downstream supercapacitor C2 and the main battery B1.

[0025] The input terminal of the rectifier module U11 is the input terminal of the energy management circuit U1. The output terminal of the rectifier module U11 is connected to the input terminal of the undervoltage lockout module U12. The output terminal of the undervoltage lockout module U12 is connected to the input terminal of the buck module U13. The output terminal of the buck module U13 is the output terminal of the energy management circuit U1. The AC power output from the piezoelectric transducer 10 enters the energy management circuit U1, is rectified into DC power by the rectifier module U11, and is temporarily stored in the front-stage energy storage capacitor C1. When the voltage of the front-stage energy storage capacitor C1 rises to the wake-up threshold, the undervoltage lockout module U12 activates the buck module U13. The buck module U13 steps down the DC power temporarily stored in the front-stage energy storage capacitor C1 and outputs the stepped-down DC power to the subsequent supercapacitor C2. When the voltage of the front-stage energy storage capacitor C1 drops to the turn-off threshold, the undervoltage lockout module U12 shuts down the buck module U13.

[0026] Regarding the structure of piezoelectric energy harvesting devices: The piezoelectric transducer 10 is preferably a PZT-5H bicrystalline cantilever beam structure (PZT-5H is a piezoelectric ceramic material), comprising a base 11, an elastic metal substrate 12 fixed in the middle of the base 11, upper and lower piezoelectric ceramic layers 13 on the surface of the elastic metal substrate 12, and a counterweight block 14 at the free end of the elastic metal substrate 12. The elastic metal substrate 12 and the upper and lower piezoelectric ceramic layers 13 form the cantilever beam of the piezoelectric transducer 10, and the first natural frequency of the cantilever beam is 24.5Hz to 25.5Hz.

[0027] To overcome pump speed fluctuations and start-up / shutdown shocks, this system introduces a nonlinear magnetic repulsion broadband flexible anti-vibration structure: the anti-vibration structure includes an upper fixed bracket 15 and a lower fixed bracket 16 fixed on both sides of the base 11. The elastic metal base plate 12, the upper fixed bracket 15, and the lower fixed bracket 16 all extend on the same side along the width direction of the base 11. The anti-vibration structure also includes moving magnets 18 disposed on the upper and lower surfaces of the counterweight block 14, and stationary magnets 17 are embedded in the free ends of the upper fixed bracket 15 and the lower fixed bracket 16.

[0028] Specifically, in order to ensure that repulsive forces are generated in both directions, the two moving magnets 18 on the upper and lower surfaces of the counterweight mass block 14 are both facing outward with the same polarity. In this embodiment, the N poles of the two moving magnets 18 are facing outward; the N pole of the upper stationary magnet 17 is facing down, and the N pole of the lower stationary magnet 17 is facing up, thereby ensuring that the upper and lower pairs of magnets strictly form a repulsive state with the same magnetic poles facing each other.

[0029] Preferably, both the upper fixed bracket 15 and the lower fixed bracket 16 are threaded with adjusting bolts, and two stationary magnets 17 are respectively embedded in the ends of two adjusting studs. In actual deployment, the initial static air gap between the stationary magnet 17 and the moving magnet 18 can be steplessly and precisely adjusted by rotating the adjusting studs to adjust their screw depth.

[0030] This structure produces a dual technical effect: First, by precisely setting the initial distance between the counterweight mass block 14 and the stationary magnet 17 through the aforementioned threaded adjustment mechanism, the nonlinear hardening stiffness (duffing effect) generated by the repulsion of like magnetic poles can be accurately controlled. This broadens the original single first-order natural frequency of the cantilever beam to a wide resonant frequency band of 24Hz to 26Hz, perfectly covering the actual working conditions of chemical plant water pumps under load fluctuations, achieving precise wide-frequency resonance matching. In this embodiment, the first-order natural frequency of the cantilever beam is 25.12Hz. Second, when the water pump starts or stops or experiences strong cavitation vibration, the drastically reduced magnet spacing generates an exponentially increased repulsive force, forming a non-contact flexible limit, effectively preventing excessive bending of the cantilever beam. The maximum effective Von Mises stress is strictly limited to 29.8MPa, far below the tensile yield limit of PZT-5H, ensuring from a fundamental physical level that the sensor can operate on the surface of the industrial water pump without mechanical failure over long periods. Von Mises stress is the equivalent stress based on shear strain energy. Both the moving magnet 18 and the stationary magnet 17 use neodymium iron boron (N35) permanent magnets; the initial static air gap between the moving magnet 18 and the stationary magnet 17 is set to 0.5mm to 1mm. In actual engineering commissioning, by finely adjusting the distance of this initial air gap, the magnitude of the nonlinear stiffness caused by the repulsion of like magnetic poles can be precisely controlled. Thus, the width of the resonant bandwidth can be flexibly customized according to the actual operating frequency band of different water pumps, taking into account both high power generation efficiency and flexible limit protection.

[0031] In terms of energy management and asymmetric impedance decoupling: The energy management circuit U1 is preferably implemented using the LTC3588-1 piezoelectric energy harvesting dedicated power management chip, which integrates a rectifier module U11, an undervoltage lockout module U12, and a buck module U13, and is configured for a constant 3.6V output. Since the piezoelectric transducer 10 outputs a current in the microamp range, it would be instantly pulled down to 0V if directly loaded. Therefore, this system adopts an asymmetric dual-capacitor decoupling architecture, utilizing the undervoltage lockout module U12 mechanism within the chip to achieve intermittent energy harvesting. like Figure 4As shown, when the energy management circuit U1 is in a low-power sleep state, the piezoelectric transducer 10 slowly charges the front-stage energy storage capacitor C1 under no-pressure conditions. When the voltage of this capacitor rises to the wake-up threshold, the internal step-down module U13 is activated, quickly transferring the energy temporarily stored in the front-stage capacitor to the rear-stage supercapacitor C2. The wake-up threshold is preferably 5.05V. When the voltage of the front-stage capacitor drops to the shutdown threshold, the energy management circuit U1 immediately re-enters the low-power sleep state. The shutdown threshold is preferably 4.02V. Through this hiccup-like high-frequency sawtooth wave charging mechanism, the system stably gathers the weak ambient energy trickle into the rear-stage supercapacitor C2, constructing an energy buffer reservoir.

[0032] Regarding image stabilization hardware interlocking and dual power supply switching: like Figure 3 As shown, the ultimate design goal of the system is to maximize the lifespan of the main battery B1. The core principle is to prioritize the consumption of energy from the downstream supercapacitor C2, and to seamlessly take over from the main battery B1 when the energy is insufficient. The dual power supply switching circuit 20 includes a voltage detection module 21, a hysteresis comparator module U2, a logic inverting module U3, a first switch K1, and a second switch K2. The working process is as follows: ① Voltage Monitoring and Hysteresis Anti-jitter: The minimum safe operating voltage of the wireless vibration sensor 30 is set to 3.0V. To allow for a voltage drop margin caused by a 100mA transient current, the drop threshold of the hysteresis comparator module U2 is set to 3.2V, and the rise threshold is set to 3.3V. This hysteresis range effectively prevents frequent comparator switching caused by transient pulses at the critical voltage point.

[0033] ② Normal charging and discharging state: When the water pump vibrates continuously, the downstream supercapacitor C2 is fully charged, and its voltage is higher than the threshold. The hysteresis comparator module U2 outputs a high level, driving the first switch K1 to close in the forward direction; at the same time, this high-level signal is converted to a low level by the logic inverting module U3, forcing the second switch K2 to open. This hardware dead-time interlocking mechanism ensures that the system is completely powered by the downstream supercapacitor C2 to the sensor, physically cutting off the consumption path of the main battery B1 and preventing reverse backflow and static leakage.

[0034] ③ Abnormal Scheduling and Backup Power Supply: When the water pump experiences sudden abnormal vibration, the wireless vibration sensor 30 irregularly sends a large number of data pulses, causing the supercapacitor to be rapidly depleted and its voltage to drop below the 3.2V threshold. The hysteresis comparator module U2 immediately flips to output a low level, opening the first switch K1; simultaneously, this low level is converted to a high level by the logic inverting module U3, triggering the second switch K2 to close. At this time, the system seamlessly switches to the main battery B1 power supply mode within microseconds, effectively preventing sensor failure. After the abnormal situation subsides, the voltage of the subsequent supercapacitor C2 rises to the 3.3V threshold under trickle charging, and the system will safely and smoothly switch back to the subsequent supercapacitor C2 power supply mode.

[0035] System-level operational verification: Figure 5 The waveforms demonstrating system-level energy dispatch and battery charge consumption during a full 600-second duty cycle of this invention are shown. From top to bottom, the waveforms represent: voltage of the supercapacitor C2, load current pulse of the wireless vibration sensor 30, and charge consumption of the main battery B1.

[0036] During the normal operating period of 0 to 300 seconds, the wireless vibration sensor 30 sends pulses at a low frequency. At this time, the supercapacitor C2 is kept above 3.0V under the trickle charging of the piezoelectric transducer 10. The charge consumption curve of the main battery B1 is a horizontal straight line, which proves that the system is powered entirely by the environmental vibration energy and achieves zero loss of the main battery B1.

[0037] During the unsteady-state abnormal operation 300 seconds later, the wireless vibration sensor 30 emitted dense high-power data pulses, and at 492 seconds, the supercapacitor dropped below 3.0V. The interlocking mechanism of the dual power supply switching circuit 20 responded quickly, and the charge consumption curve of the main battery B1 rose in a step-like manner and smoothly took over the power supply, proving that the system effectively avoided node power failure under extreme high load conditions, greatly improving the robustness and battery life of the industrial IoT node.

[0038] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A piezoelectric vibration energy recovery and battery management system for industrial water pumps, used to power vibration sensors, characterized in that, include: A piezoelectric transducer used to convert the vibration energy of an industrial water pump into alternating current. Energy management circuits used to convert AC power into DC power and transport DC power; A front-stage energy storage capacitor used to temporarily store DC power; The supercapacitor is used to store the DC energy temporarily stored in the preceding energy storage capacitor. The main battery used to provide backup power; A dual power supply switching circuit that is connected to the downstream supercapacitor and the main battery respectively; The dual power supply switching circuit includes a hysteresis comparator module and a logic inverting module connected to the output of the hysteresis comparator module. The hysteresis comparator module is used to compare the voltage state of the subsequent supercapacitor with a preset hysteresis threshold window and output a corresponding control signal. The logic inverting module is used to respond to the control signal to control the subsequent supercapacitor and the main battery to selectively connect to the vibration sensor for power supply. When the voltage of the supercapacitor rises to the rising threshold, the dual power supply switching circuit supplies power to the wireless vibration sensor through the supercapacitor; when the voltage of the supercapacitor drops to the falling threshold, the dual power supply switching circuit supplies power to the wireless vibration sensor through the main battery. The front-stage energy storage capacitor matches the high internal resistance characteristics of the piezoelectric transducer to ensure the high-frequency hiccup start of the undervoltage lockout module; the rear-stage supercapacitor matches the low impedance heavy-load characteristics of the sensor to achieve physical isolation and impedance decoupling between the microwatt-level energy source and the hundred-milliwatt-level pulse load. The vibration frequency of the industrial water pump is in the range of 24Hz to 26Hz.

2. The piezoelectric vibration energy recovery and battery management system according to claim 1, characterized in that: The dual power supply switching circuit also includes a voltage detection module, a first switch, and a second switch; The voltage detection module is used to sample the voltage state of the subsequent supercapacitor; The first switch is connected in series in the power supply circuit between the downstream supercapacitor and the vibration sensor; the second switch is connected in series in the power supply circuit between the main battery and the vibration sensor.

3. The piezoelectric vibration energy recovery and battery management system according to claim 2, characterized in that: The signal input terminal of the hysteresis comparator module is connected to the output terminal of the voltage detection module, the signal output terminal of the hysteresis comparator module is directly connected to the control terminal of the first switch, and the signal output terminal of the hysteresis comparator module is connected to the control terminal of the second switch via the logic inverting module.

4. The piezoelectric vibration energy recovery and battery management system according to claim 1, characterized in that: The preset hysteresis threshold window is defined by a falling threshold and a rising threshold; The drop threshold is set to be higher than the minimum safe operating voltage of the vibration sensor, and the rise threshold is set to be lower than the rated voltage of the main battery.

5. The piezoelectric vibration energy recovery and battery management system according to claim 1, characterized in that: The energy management circuit integrates a rectifier module, an undervoltage lockout module, and a voltage conversion module. The undervoltage lockout module is configured to monitor the terminal voltage of the front-stage energy storage capacitor. The input terminal of the rectifier module constitutes the input terminal of the energy management circuit, the output terminal of the rectifier module is connected to the input terminal of the undervoltage lockout module, the output terminal of the undervoltage lockout module is connected to the input terminal of the voltage conversion module, and the output terminal of the voltage conversion module constitutes the output terminal of the energy management circuit.

6. The piezoelectric vibration energy recovery and battery management system according to claim 1, characterized in that: The piezoelectric transducer includes a cantilever beam fixed at one end and a nonlinear magnetic repulsion broadband flexible anti-vibration structure; the cantilever beam has a first-order natural frequency, and the anti-vibration structure is used to broaden the resonant frequency band, so that the system forms a wide resonant frequency band including the first-order natural frequency, and provides non-contact magnetic repulsion flexible limiting when the vibration amplitude of the cantilever beam exceeds a preset threshold. The fixed end of the cantilever beam is located on one side of the base, and the free end of the cantilever beam is provided with a counterweight mass block. The shock-resistant structure includes an upper fixed bracket and a lower fixed bracket fixed on both sides of the base, a static magnet at the free end of the upper fixed bracket and the lower fixed bracket, and a moving magnet on the upper and lower surfaces of the counterweight block, respectively. The static magnet and the moving magnet have the same magnetic poles facing each other.

7. The piezoelectric vibration energy recovery and battery management system according to claim 6, characterized in that: The cantilever beam consists of an elastic metal substrate and piezoelectric ceramic layers attached to the upper and lower surfaces of the elastic metal substrate.

8. The piezoelectric vibration energy recovery and battery management system according to claim 7, characterized in that: The elastic metal substrate is a 301 elastic steel substrate, and the piezoelectric ceramic layer is a PZT-5H piezoelectric ceramic sheet. The upper and lower PZT-5H piezoelectric ceramic sheets form a series electrical structure.

9. The piezoelectric vibration energy recovery and battery management system according to claim 6, characterized in that: The first-order natural frequency is 24.5Hz to 25.5Hz, and the wide-range resonant frequency band is 24Hz to 26Hz.

10. The piezoelectric vibration energy recovery and battery management system according to claim 9, characterized in that: The front-stage energy storage capacitor is a ceramic capacitor with a capacitance value between 5μF and 20μF, and the back-stage supercapacitor is a farad capacitor with a capacitance value between 0.2F and 1F.

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