Self-powered temperature monitoring method for large generator set

Abstract

The invention belongs to the field of large generator set temperature online monitoring, and particularly relates to a self-powered temperature monitoring method for a large generator set, and the method comprises the following steps: S01, carrying out the energy capture of a magnetic flux leakage environment, a vibration environment and a temperature difference environment; s02, stabilizing energy captured from magnetic flux leakage, vibration and temperature difference environments; the three kinds of environment energy of magnetic leakage, vibration and temperature difference are collected at the same time, and voltage is output stably; step S03, carrying out sensing temperature measurement on the stabilized energy; and step S04, remote control is realized through wireless communication, and data management is realized. The industrial self-powered temperature monitoring system established through the method can effectively solve the problem of online measurement of the temperature of the rotor, ensures safe operation of a large generator set, and brings better economic benefits to enterprises.

Description

Technical Field

[0001] The present application belongs to the field of online temperature monitoring of large generator sets, and specifically relates to a self-powered temperature monitoring method for large generator sets. Background Art

[0002] As the cornerstone of modern society, electricity is vital to social development and daily life. As the core of the power system, large-scale generators convert mechanical energy into electrical energy to provide necessary energy support for infrastructure such as homes, factories, transportation and medical care. The stable operation of these infrastructures is not only related to people's quality of life, but also the guarantee of national economic development and social stability.

[0003] In the operation of large-scale generator sets, monitoring parameters such as temperature is of great significance to ensure the safe operation of the equipment. For example, by monitoring the stator and rotor temperature of the generator, the equipment can be prevented from overheating and the insulation material can be protected, thereby avoiding aging and damage of mechanical parts due to high temperature. In addition, the timely discovery and processing of abnormal parameters can not only improve the operating efficiency of the equipment, but also reduce energy waste and maintenance costs, while ensuring that the equipment operates in the best condition. With the development of industrial automation and intelligent manufacturing, traditional wired monitoring methods are gradually unable to meet the needs of modern industry due to their shortcomings such as complex wiring and difficult maintenance. Summary of the invention

[0004] In order to overcome the above problems existing in the prior art, a self-powered temperature monitoring method for large generator sets is proposed.

[0005] To achieve the above technical effects, the solution of this application is as follows:

[0006] A self-powered temperature monitoring method for a large generator set comprises the following steps:

[0007] Step S01. Capture energy in the environment of magnetic leakage, vibration and temperature difference;

[0008] (1) In view of the magnetic field environment in large generator sets, electromagnetic elements are used to collect alternating magnetic field energy and convert it into electrical energy based on the principle of electromagnetic induction;

[0009] Furthermore, according to the law of electromagnetic induction, a closed coil will generate an induced electromotive force in a three-way alternating magnetic field, and increasing the magnetic core will enhance the magnetic induction intensity. According to the simulation, the output voltage of the coil on the I-shaped magnetic core is the highest. Through the energy collection PCB, the coil is connected to the energy collection PCB input terminal through the input terminal to input energy, and the energy collection PCB outputs energy stably to the outside through the remaining two terminals.

[0010] According to Faraday's law of electromagnetic induction, when the magnetic flux of a closed conductor loop in a magnetic field changes, an induced current is generated in the loop, indicating that an electromotive force ε is induced in the loop. in , and the magnitude of the induced electromotive force is proportional to the rate of change of the magnetic flux ψ with time t.

[0011]

[0012] The magnetic flux in the closed loop is:

[0013]

[0014] in Represents magnetic induction intensity, which is a vector that describes the distribution of magnetic field in space; It represents a tiny area element, which is a vector whose direction is consistent with the normal direction of the area and whose magnitude is equal to the value of the area.

[0015] The induced electromotive force of this closed loop is:

[0016]

[0017] in Represents the electric field intensity, which is a vector that describes the distribution of the electric field in space; Represents a tiny path element, a vector along the path direction, whose magnitude is equal to the path length; we can get:

[0018]

[0019] The closed coil loop is static, and the three-way alternating magnetic field linked to it changes with time, which will generate an induced electromotive force:

[0020]

[0021] Where x represents a coordinate in space.

[0022] In terms of structural design: adding magnetic cores will increase the magnetic induction intensity. According to the simulation, COMSOL is used to simulate magnetic cores of different shapes in the magnetic field, and coils are added to collect alternating magnetic field energy. The simulation results show that the voltage collected by the I-shaped magnetic core is the highest. Experiments are carried out to explore the energy collection of magnetic core materials. The magnetic field energy in the environment is collected through the I-shaped magnetic core and the coils on the I-shaped magnetic core. The number of coil layers on the I-shaped magnetic core can be modified according to the on-site magnetic field strength. The more coil layers, the higher the output voltage of the coil. According to the simulation, the I-shaped magnetic core and the coil.

[0023] Material selection: The core material of the I-shaped magnetic core and the coil is made of 45 steel, and the coil is hand-wound with oxygen-free pure copper enameled wire. The number of coil layers and turns can be adjusted according to the actual magnetic field strength at the application site to obtain the appropriate voltage output.

[0024] Energy collection: Through the energy collection PCB, the piezoelectric sheet, I-shaped magnetic core and coil are connected to the energy collection PCB through the terminal, and the energy collection PCB outputs energy to the outside through the terminal.

[0025] (2) In view of the vibration environment in large generator sets, piezoelectric materials and energy harvesting chips are used to collect vibration energy and convert it into electrical energy based on the piezoelectric effect;

[0026] Furthermore, the entire device is connected to the stator of the hydro-turbine generator through a fixed plate of the piezoelectric electromagnetic coupling vibration energy collection device. When the generator starts to run, it will generate vibration with a characteristic frequency of 50 Hz. The spring used in the piezoelectric electromagnetic coupling vibration energy collection device can resonate at 50 Hz, thereby increasing the original vibration input.

[0027] When the vibration generated by the generator stator drives the transducer cantilever beam to swing up and down, the piezoelectric material attached to the transducer cantilever beam will also be stretched or compressed accordingly to produce deformation. The working mode of the piezoelectric material when collecting vibration energy is d 31 ;

[0028] d 31 The stress direction of the working mode is 1, and the polarization direction is 3, which are orthogonal. The output of the voltage V and charge Q in the open circuit can be expressed as follows:

[0029]

[0030] Among them, σ is stress; g is the piezoelectric voltage coefficient; d is the piezoelectric coefficient; H is the thickness of the piezoelectric layer, and A is the electrode area.

[0031] The straight-beam piezoelectric cantilever beam structure in the piezoelectric electromagnetic coupling vibration energy harvesting device includes a cantilever beam, one end of the cantilever beam is fixed to a substrate, a piezoelectric sheet is fixed on the substrate, and the other end of the substrate is a free end and is fixed with a mass block. The resonant frequency of the piezoelectric cantilever beam is changed by adjusting the weight of the mass block, and the piezoelectric sheet is clamped by a clamping structure to make the piezoelectric material deform to generate more energy. When the ambient vibration frequency is close to the natural frequency of the cantilever beam, the output of the piezoelectric sheet increases sharply. The typical value of the vibration frequency of the generator stator is 50Hz, and the bandwidth is extremely narrow. The mass of the mass block at the end of the cantilever beam is adjusted to make the resonant frequency of the cantilever beam consistent with the vibration frequency of the generator stator.

[0032] The calculation steps of the piezoelectric mass block are as follows:

[0033]

[0034] Where m t is the mass of the end counterweight, k is the effective stiffness, f is the resonant frequency, and m is the effective mass.

[0035] Secondly, the up and down swing of the transducer cantilever beam will drive the electromagnetic transducer at the end to vibrate. Each electromagnetic transducer consists of a magnet barrel, two annular magnets and a copper coil. The two magnets have the same poles facing each other and one of the magnets is fixedly connected to the bottom of the magnet barrel, while the other is not fixed. One of the magnets will be magnetically suspended, and the copper coil is fixedly connected to the magnet barrel. When the magnet barrel vibrates, due to the inertia of the object, the copper coil will cut the magnetic lines of force, and according to the electromagnetic induction phenomenon, electricity will be generated, thus completing the conversion of electromagnetic vibration energy into electrical energy.

[0036] (3) In view of the temperature difference environment in large-scale power generation units, based on the Seebeck effect, the thermoelectric power generation module adopts thermoelectric sheets. The thermoelectric sheets are insulated by filling with silica aerogel and equipped with a passive air cooling system to collect the temperature difference energy of the generator set and convert it into electrical energy.

[0037] Furthermore, the two ends of the thermoelectric power generation sheet of the thermoelectric power generation module are the hot end and the cold end of the thermoelectric material itself. When there is a temperature difference between the two ends of the thermoelectric power generation sheet, a directional movement of carriers will occur inside it, and finally a stable electromotive force will be generated, thereby completing the conversion of temperature difference energy into electrical energy.

[0038] The thermoelectric power generation module uses two thermoelectric power generation chips. Each individual terminal can be calculated by Seebeck effect to obtain the theoretical thermoelectric power generation voltage value:

[0039]

[0040] In the formula, S AB (T) is the relative Seebeck coefficient on both sides of the thermoelectric power generation sheet, which is a value that changes with temperature and is determined by the thermoelectric material itself. T1 and T2 are the temperature values ​​of the ambient hot end and the ambient cold end respectively;

[0041] At a certain temperature, the Seebeck coefficient is a certain value, and the above formula can be simplified to:

[0042] V 0 =S AB ΔT

[0043] Where ΔT is the ambient temperature difference,

[0044] The total power generation voltage of the entire temperature difference power generation module is:

[0045] V = 127 × 2 × V 0

[0046] =127×2×SAB ΔT

[0047] Based on the thermoelectric properties of thermoelectric materials, the design is aimed at making the temperature difference between the two ends of the thermoelectric power generation sheet as large as possible:

[0048] In terms of specific structural design, the upper and lower ends of the thermoelectric power generation sheet are the heat sink and the hot end respectively. The hot end is in direct contact with the ambient heat source, and a high-temperature environment is provided for the hot end of the thermoelectric power generation sheet through solid heat transfer.

[0049] The radiator uses aluminum as the heat dissipation material, and the hot end uses copper as the heat transfer material.

[0050] Step S02. Stabilize the energy captured from magnetic flux leakage, vibration and temperature difference environment;

[0051] The energy stabilization module collects three kinds of environmental energy, namely magnetic leakage, vibration and temperature difference, and outputs a stable 3.3V voltage.

[0052] The energy stabilization module adopts a back-end fusion method, based on a multi-energy fusion method of graded energy storage, to make independent impedance matching and storage of leakage magnetic, vibration, and temperature difference energy, and then fuse the energy to finally achieve stable output; the module uses 3 ADP5091 chips to realize three-way energy input, and uses supercapacitors to store the input energy, and then uses a DC-to-DC voltage stabilization circuit design to stabilize the energy in the supercapacitor at 3.3V for output.

[0053] The three input ends of the module have independent DC / DC boost circuits with MPPT functions, which can be adjusted through different high and low level states of REG_D0 and REG_D1 pins. When REG_D1 is high, it can work in boost mode. After boost conversion, it is directly transmitted to the ADP5091 chip, so that the energy is stored in the supercapacitor, realizing the conversion and stabilization of low-input and high-output energy; the module can boost and stabilize 80mV~3.3V energy, and the input power range is 16uW to 600mW; the open-circuit voltage ratio method is adopted, the open-circuit voltage is periodically detected through the MTTP pin, and the voltage is adjusted to achieve maximum power point tracking of the three energies.

[0054] The calculation formula of the open circuit voltage ratio method is:

[0055] V MPPT = k × V OC

[0056] This formula is based on the maximum power voltage V MPPT and open circuit voltage V OC The linear relationship of k is set manually, and k is usually set between 0.5 and 0.8:

[0057] The energy storage device uses a supercapacitor. Under constant current charging, the charging current I remains unchanged, and the voltage change rate of the supercapacitor is I / C. Then the voltage across the supercapacitor is:

[0058]

[0059] V c0 is the initial voltage of the capacitor, and the charging time is T:

[0060]

[0061] Where V cT is the voltage of the supercapacitor at time T.

[0062] The constant current charging efficiency η is as follows:

[0063]

[0064] Where C is the capacitance of the supercapacitor, R ESR is the equivalent internal resistance;

[0065] The efficiency of constant current charging method is related to charging current I and equivalent internal resistance R ESR As the charging time increases, the higher the initial voltage of the capacitor, the higher the charging efficiency, but the corresponding charging speed is also slower.

[0066] The multi-energy fusion method based on graded energy storage uses multiple supercapacitors to store the three energies in the rear-stage supercapacitors and charge the first-stage supercapacitors. A diode and a low-resistance resistor are connected in series between the rear-stage supercapacitor and the first-stage supercapacitor.

[0067] The stable output of energy adopts the circuit design of LDO low-voltage difference linear regulator, and the energy stored in the first-stage supercapacitor is directly passed through the LDO circuit to achieve stable output of energy; the circuit includes a reference voltage source, a sampling output voltage, an error amplifier and a series adjustment tube. The amplifier is used to control the voltage step-down of the regulator to continuously reach the required output voltage value. The output voltage is divided by the feedback resistor to the input of the error amplifier. When the output voltage is higher than the set value, the internal loop will change the driving voltage to increase the conduction voltage drop of the tube, thereby reducing the output voltage. When the output voltage is higher than the set value, it will in turn increase the output voltage, and finally achieve stable energy output.

[0068] Step S03. Perform sensor temperature measurement;

[0069] The sensing temperature measurement part is equipped with 8-way interfaces, external K-type thermocouples, and supports multi-channel temperature measurement. The module receives power from the energy collection part or external power supply, and has two interfaces, which are connected to the energy management fusion part and the low-power wireless communication part respectively, and transmits the measured temperature data wirelessly to the gateway;

[0070] Multi-channel temperature measurement is based on a temperature measurement chip and two eight-way multiplexing chips. Eight K-type thermocouples are connected to the temperature measurement chip in sequence through the multiplexing chip to achieve eight-way temperature measurement with a single temperature measurement chip.

[0071] Step S04: Implement remote control and data management through wireless communication.

[0072] The wireless communication is based on the E220-400T22D chip, and uses LoRa technology to achieve remote data transmission. It is equipped with two interfaces: one interface uses the UART protocol for full-duplex serial asynchronous communication, directly connected to the energy management fusion part or the temperature sensor array, to achieve the collection and wireless transmission of power and temperature data. These data are then sent to the gateway and finally displayed on the server; the other interface is an SMA interface for connecting the antenna.

[0073] The data management adopts B / S architecture, which includes four parts: monitoring status, monitoring and early warning, equipment parameter adjustment, and system maintenance and management, to achieve real-time monitoring, display and early warning of the rotor temperature of the generator set and online monitoring of the monitoring system and sensor status.

[0074] Compared with the prior art, the beneficial effects of this application are:

[0075] 1. Aiming at the problems of complex wiring and difficult maintenance in the online monitoring of rotor temperature in large hydro-turbine generators and steam turbine generator sets, an energy capture method, energy stabilization and temperature sensing measurement method that can collect the internal magnetic field, vibration and temperature difference energy of the equipment are established. At the same time, a wireless communication method and remote control and data management are established to solve the maintenance problems of the online monitoring system, and realize the remote transmission of the self-powered sensing system status and rotor temperature data. The industrial self-powered temperature monitoring system established by this method can effectively solve the problem of online measurement of rotor temperature, ensure the safe operation of large generator sets, and bring better economic benefits to enterprises.

[0076] 2. Strong autonomous power supply capability: Through a variety of energy harvesting technologies, the system can continue to operate without an external power supply, reducing maintenance costs.

[0077] 3. High environmental adaptability: The system design takes into account complex environments such as high temperature, vibration, and oil pollution, ensuring the stability and reliability of the sensor.

[0078] 4. Reliable data transmission: The use of Lora wireless communication technology ensures the quality and distance of data transmission in complex industrial environments.

[0079] 5. Modular design: The system integrates energy collection, management, sensor measurement and wireless communication modules for easy installation and maintenance.

[0080] 6. High degree of intelligence: Through data management software, users can monitor turbine temperature in real time, detect and handle abnormalities in time, and improve the operating efficiency and safety of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 Implementation flow of self-powered temperature monitoring method.

[0082] Figure 2 This is a working diagram of vibration energy harvesting. DETAILED DESCRIPTION

[0083] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0084] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0085] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0086] In the description of the present application, it should be noted that the terms "upper", "vertical", "inner", "outer", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the application is usually placed when in use, or the orientation or position relationship commonly understood by those skilled in the art. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0087] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0088] A self-powered temperature monitoring method for a large generator set comprises the following steps:

[0089] Step S01. Capture energy in the environment of magnetic leakage, vibration and temperature difference;

[0090] (1) In view of the magnetic field environment in large generator sets, electromagnetic elements are used to collect alternating magnetic field energy and convert it into electrical energy based on the principle of electromagnetic induction;

[0091] Furthermore, according to the law of electromagnetic induction, a closed coil will generate an induced electromotive force in a three-way alternating magnetic field, and increasing the magnetic core will enhance the magnetic induction intensity. According to the simulation, the output voltage of the coil on the I-shaped magnetic core is the highest. Through the energy collection PCB, the coil is connected to the energy collection PCB input terminal through the input terminal to input energy, and the energy collection PCB outputs energy stably to the outside through the remaining two terminals.

[0092] According to Faraday's law of electromagnetic induction, when the magnetic flux of a closed conductor loop in a magnetic field changes, an induced current is generated in the loop, indicating that an electromotive force ε is induced in the loop. in , and the magnitude of the induced electromotive force is proportional to the rate of change of the magnetic flux ψ with time t.

[0093]

[0094] The magnetic flux in the closed loop is:

[0095]

[0096] in Represents magnetic induction intensity (also called magnetic field intensity), which is a vector that describes the distribution of the magnetic field in space; It represents a tiny area element, which is a vector whose direction is consistent with the normal direction of the area and whose magnitude is equal to the value of the area.

[0097] The induced electromotive force of this closed loop is:

[0098]

[0099] in Represents the electric field intensity, which is a vector that describes the distribution of the electric field in space; Represents a tiny path element, a vector along the path direction, whose magnitude is equal to the path length; we can get:

[0100]

[0101] The closed coil loop is stationary, and the three-way alternating magnetic field linked to it changes with time, which will generate an induced electromotive force. This induced electromotive force is called induced electromotive force.

[0102]

[0103] Where x represents a coordinate in space, which means that x means a coordinate direction in space. For example, in a rectangular coordinate system, x can represent a coordinate in a certain direction (such as the direction of the x-axis).

[0104] In terms of structural design: adding a magnetic core will increase the magnetic induction intensity. According to the simulation, COMSOL is used to simulate magnetic cores of different shapes in a magnetic field, and coils are added to collect alternating magnetic field energy. The simulation results show that the voltage collected by the I-shaped magnetic core is the highest. Experiments are carried out to explore the energy collection of magnetic core materials. The magnetic field energy in the environment is collected through the I-shaped magnetic core and the coils on the I-shaped magnetic core. The number of coil layers on the I-shaped magnetic core can be modified according to the on-site magnetic field strength. The more coil layers, the higher the output voltage of the coil. According to the simulation, the I-shaped magnetic core and the coil (the simulation found that under the same other conditions, the output voltage generated by the coil on the I-shaped magnetic core is the highest).

[0105] Material selection: The core material of the I-shaped magnetic core and the coil is made of 45 steel, and the coil is hand-wound with oxygen-free pure copper enameled wire. The number of coil layers and turns can be adjusted according to the actual magnetic field strength at the application site to obtain the appropriate voltage output.

[0106] Energy collection: Through the energy collection PCB, the piezoelectric sheet, I-shaped magnetic core and coil are connected to the energy collection PCB through the terminal, and the energy collection PCB outputs energy to the outside through the terminal.

[0107] (2) In view of the vibration environment in large generator sets, piezoelectric materials and energy harvesting chips are used to collect vibration energy and convert it into electrical energy based on the piezoelectric effect;

[0108] Furthermore, the entire device is connected to the stator of the hydro-turbine generator through a fixed plate of the piezoelectric electromagnetic coupling vibration energy collection device. When the generator starts to run, it will generate vibration with a characteristic frequency of 50 Hz. The spring used in the piezoelectric electromagnetic coupling vibration energy collection device can resonate at 50 Hz, thereby increasing the original vibration input.

[0109] When the vibration generated by the generator stator drives the transducer cantilever beam to swing up and down, the piezoelectric material attached to the transducer cantilever beam will also be stretched or compressed accordingly to produce deformation. In the process of using piezoelectric materials for vibration energy collection, the positive piezoelectric effect is mainly used to convert mechanical vibration into electrical energy. When the external input excitation size and phase are consistent, the output of piezoelectric materials in different working modes will be significantly different. The working mode of the piezoelectric material during vibration energy collection is d 31 , the working diagram is as follows Figure 2 shown.

[0110] d 31 The stress direction of the working mode is 1, and the polarization direction is 3, which are orthogonal. The output of the voltage V and charge Q in the open circuit can be expressed as follows:

[0111]

[0112] Among them, σ is stress; g is the piezoelectric voltage coefficient; d is the piezoelectric coefficient; H is the thickness of the piezoelectric layer, and A is the electrode area.

[0113] In terms of piezoelectric material selection, the commonly used piezoelectric materials in the field of vibration energy harvesting are PZT (lead zirconate titanate), AlN, ZnO and PVDF (polyvinylidene fluoride), etc. Each vibration energy harvesting piezoelectric sheet contains 4 layers of piezoelectric materials, and the base material uses FR-4 grade epoxy glass cloth laminate, which has a low loss coefficient and can be used well in a vibration environment for a long time.

[0114] The straight-beam piezoelectric cantilever beam structure in the piezoelectric electromagnetic coupling vibration energy harvesting device includes a cantilever beam, one end of the cantilever beam is fixed to the substrate, the piezoelectric sheet is adhered or otherwise fixed to the substrate, and the other end of the substrate is a free end and is fixed with a mass block. The resonant frequency of the piezoelectric cantilever beam is changed by adjusting the weight of the mass block. The piezoelectric sheet is clamped by a clamping structure to allow the piezoelectric material to have a larger deformation to generate more energy. When the ambient vibration frequency is close to the natural frequency of the cantilever beam, the output of the piezoelectric sheet increases sharply. The typical value of the vibration frequency of the generator stator is 50Hz, and the bandwidth is extremely narrow. It is necessary to adjust the mass of the mass block at the end of the cantilever beam to make the resonant frequency of the cantilever beam consistent with the vibration frequency of the generator stator.

[0115] The calculation steps of the piezoelectric mass block are as follows:

[0116]

[0117] Where m t is the mass of the end counterweight, k is the effective stiffness, f is the resonant frequency, and m is the effective mass; the PPA product has three clamping methods, and the default clamping position ensures that the piezoelectric film has sufficient strain during energy collection and sensing.

[0118] Secondly, the up and down swing of the transducer cantilever beam will also drive the electromagnetic transducer at the end to vibrate. Each electromagnetic transducer consists of a magnet barrel, two annular magnets and a copper coil. The two magnets have opposite poles and one of them is fixed to the bottom of the magnet barrel, while the other is not fixed. In this way, one magnet will be magnetically suspended and the copper coil is fixed to the magnet barrel, that is, the relative position of the two remains unchanged. When the magnet barrel vibrates, due to the inertia of the object, the unfixed magnet cannot maintain the same relative position with the copper coil. Then, the copper coil will cut the magnetic flux lines, and according to the electromagnetic induction phenomenon, electricity will be generated, thus completing the conversion of electromagnetic vibration energy to electrical energy.

[0119] (3) In response to the medium-amplitude temperature difference environment of large-scale power generation units, based on the Seebeck effect, the thermoelectric power generation module uses thermoelectric sheets. The thermoelectric sheets are insulated by filling with silica aerogel and equipped with a passive air cooling system to collect the temperature difference energy of the generator set and convert it into electrical energy.

[0120] Furthermore, the two ends of the thermoelectric power generation sheet of the thermoelectric power generation module are the hot end and the cold end of the thermoelectric material itself. When there is a temperature difference between the two ends of the thermoelectric power generation sheet, a directional movement of carriers will occur inside it, and finally a stable electromotive force will be generated, thereby completing the conversion of temperature difference energy into electrical energy.

[0121] In order to maximize the utilization efficiency of environmental waste heat under the projection area requirement, the thermoelectric power generation module uses two thermoelectric power generation sheets. Each individual terminal can be calculated by the Seebeck effect to obtain the theoretical thermoelectric power generation voltage value:

[0122]

[0123] In the formula, S AB (T) is the relative Seebeck coefficient on both sides of the thermoelectric sheet, which is a value that changes with temperature (increases with increasing temperature) and is determined by the thermoelectric material itself. T1 and T2 are the temperature values ​​of the ambient hot end and the ambient cold end, respectively;

[0124] At a certain temperature, the Seebeck coefficient is a certain value, and the above formula can be simplified to:

[0125] V 0 =S AB ΔT

[0126] Where ΔT is the ambient temperature difference,

[0127] The total power generation voltage of the entire temperature difference power generation module is:

[0128] V = 127 × 2 × V 0

[0129] =127×2×S AB ΔT

[0130] Based on the thermoelectric properties of thermoelectric materials, the design is aimed at making the temperature difference between the two ends of the thermoelectric power generation sheet as large as possible:

[0131] In terms of specific structural design, the upper and lower ends of the thermoelectric generator are the heat sink and the hot end respectively. The hot end is in direct contact with the ambient heat source, providing a high-temperature environment for the hot end of the thermoelectric generator through solid heat transfer. Compared with the pin-fin heat dissipation structure, the fin-type heat dissipation structure has better fluid flow conditions and can better exchange heat with the air fluid environment to fully release redundant heat, thereby generating a larger temperature difference at both ends of the thermoelectric generator.

[0132] In terms of material selection, both copper and aluminum have good thermal conductivity. The thermal conductivity of copper is higher than that of aluminum, but aluminum has a smaller heat capacity and can quickly generate heat changes, so it can take away heat faster when used as a heat sink. At the same time, copper has a higher density than aluminum. Within the same weight limit, aluminum heat sinks have a larger heat dissipation area. Therefore, the heat sink uses aluminum as the heat dissipation material, and the hot end uses copper as the heat transfer material, which can produce a larger temperature difference in the entire process of hot end heat transfer and heat dissipation of the heat sink, thereby improving the overall efficiency.

[0133] Step S02. Stabilize the energy captured from magnetic flux leakage, vibration and temperature difference environment;

[0134] The energy stabilization module collects three kinds of environmental energy, namely magnetic leakage, vibration and temperature difference, and outputs them stably as 3.3V voltage, while ensuring high conversion efficiency.

[0135] The energy stabilization module adopts a back-end fusion method, based on a multi-energy fusion method of graded energy storage, to make independent impedance matching and energy storage of leakage magnetic, vibration, and temperature difference energy, and then fuse the energy for final stable output; the module uses three ADP5091 chips to realize three-way energy input, and uses supercapacitors to store the input energy, and then uses a DC-to-DC voltage stabilization circuit design to stabilize the energy in the supercapacitor at 3.3V for output.

[0136] The module has a three-way MPPT DC / DC boost circuit, which can be adjusted through the different high and low level states of the REG_D0 and REG_D1 pins. When REG_D1 is high, it can work in boost mode. Since the three environmental energies of leakage magnetic field, vibration and temperature difference are relatively weak, this circuit can be used to boost and convert the weak energy and transmit it directly to the ADP5091 chip, thereby storing the energy in the supercapacitor, realizing the conversion and stability of energy with low input and high output; the module boosts and stabilizes the energy of 80mV'3.3V, and the input power range is 16 microwatts to 600 milliwatts; at the same time, the circuit has the maximum power point tracking function. Since the environment changes at any time in actual situations, the corresponding three energies are also very unstable. In this case, its output power performance will also be greatly affected. Therefore, the maximum power point tracking function is used to make the output power reach the maximum value. The open circuit voltage method is used. The circuit design of this method is more concise and low-power, and it is also the most commonly used in the internal circuit of low-power chips. The open-circuit voltage is periodically detected through the MTTP pin and the voltage is adjusted to achieve maximum power point tracking of the three energies.

[0137] V MPPT = k × V OC

[0138] This formula is based on the maximum power voltage V MPPT and open circuit voltage V OC Different systems will use different constants k to optimize energy conversion. The constant k can generally be set to 0.5. Through experiments, it is set to between 0.73 and 0.80 to achieve better results.

[0139] The energy storage device uses supercapacitors, which not only charge quickly but also have high power density. In addition, supercapacitors have low energy loss, and the leakage current can be as low as one hundred microamperes. In this case, even mW-level input power can charge them. And the capacitor can be charged and discharged many times, with a longer life. During the charging process of supercapacitors, the maximum efficiency of the constant voltage charging method does not exceed 55%. In the constant current charging method, the charging efficiency will increase over time, and the efficiency can even reach 90%.

[0140] In the constant current charging mode, where I is the constant charging current and the voltage change rate of the supercapacitor is I / C, the voltage across the supercapacitor is:

[0141]

[0142] V c0 is the initial voltage of the capacitor, and the charging time is T:

[0143]

[0144] Where V cT is the voltage of the supercapacitor at time Y.

[0145] The constant current charging efficiency η is as follows:

[0146]

[0147] Where C is the capacitance of the supercapacitor, R ESR is the equivalent internal resistance;

[0148] The efficiency of constant current charging method is related to charging current I and equivalent internal resistance R ESR As the charging time increases, the higher the initial voltage of the capacitor, the higher the charging efficiency, but the corresponding charging speed is slower. Therefore, the capacitance of the supercapacitor needs to be selected within a suitable range.

[0149] The multi-energy fusion method based on hierarchical energy storage uses multiple supercapacitors to store the three energies in the subsequent supercapacitors respectively, and charges the first-level supercapacitors. A diode and a low-resistance (10 ohm) resistor are connected in series between the subsequent supercapacitors and the first-level supercapacitors. The diode plays an isolation role to prevent the current from flowing back and causing the first-level energy to flow into the subsequent stage, eliminating energy leakage. The low-resistance resistor prevents pulse current. Without this resistor, the subsequent capacitor will instantly charge the first-level capacitor to form a pulse current. Most of the energy loss is radiated in the form of electromagnetic waves, which has a large loss and also reduces the life of the supercapacitor. The energy fusion architecture using hierarchical energy storage uses multiple small-capacity capacitors instead of a single large-capacity capacitor. On the one hand, it can improve the charging efficiency of the capacitor at the same voltage. On the other hand, it can avoid the charging limitation caused by the leakage current of the capacitor, ensuring that energy storage can still be effectively performed under the condition of smaller power input.

[0150] The stable output of energy adopts the circuit design of LDO low-voltage difference linear regulator, and the energy stored in the first-stage supercapacitor is directly passed through the LDO circuit to achieve stable output of energy; the circuit mainly includes a reference voltage source, a sampling output voltage, an error amplifier and a series adjustment tube. The amplifier is used to control the voltage step-down of the regulator to continuously reach the required output voltage value. The output voltage is divided by the feedback resistor to the input of the error amplifier. When the output voltage is higher than the set value, the internal loop will change the driving voltage to increase the conduction voltage drop of the tube, thereby reducing the output voltage. When the output voltage is higher than the set value, it will in turn increase the output voltage, and finally achieve stable energy output.

[0151] Step S03. Perform sensor temperature measurement;

[0152] The sensing temperature measurement part is equipped with 8-way interfaces, external K-type thermocouples, and supports multi-channel temperature measurement. The module receives power from the energy collection part or external power supply, and has two interfaces, which are connected to the energy management fusion part and the low-power wireless communication part respectively, and transmits the measured temperature data wirelessly to the gateway;

[0153] Multi-channel temperature measurement is based on a temperature measurement chip and two eight-way multiplexing chips. Eight K-type thermocouples are connected to the temperature measurement chip in sequence through the multiplexing chip to achieve eight-way temperature measurement with a single temperature measurement chip.

[0154] The specific steps are:

[0155] (1) Initialization of temperature measurement chip and eight-way multiplexing chip;

[0156] (2) Control the multiplexing chip to turn on the thermocouple that needs to be measured;

[0157] (3) Read the temperature measurement chip to obtain temperature measurement data.

[0158] Step S04: Implement remote control and data management through wireless communication.

[0159] Wireless communication uses LoRa technology to achieve long-distance data transmission; equipped with two interfaces: one interface uses UART protocol for full-duplex serial asynchronous communication, directly connected to the energy management fusion part or temperature sensor array, to achieve power and temperature data collection and wireless transmission. These data are then sent to the gateway and finally displayed on the server; the other interface is an SMA interface for connecting the antenna.

[0160] Data management adopts B / S architecture, i.e. browser / server architecture. It includes four parts: monitoring status, monitoring warning, equipment parameter adjustment, system maintenance and management, which can realize real-time monitoring, display and warning of the rotor temperature of the generator set and online monitoring of the monitoring system and sensor status.

[0161] Long-distance wireless communication uses LoRa communication module and LoRa technology to achieve remote data transmission. The module is directly connected to the energy management fusion module and the temperature sensor array through full-duplex asynchronous serial communication via UART protocol, so as to package and package the power information of the energy management fusion module and the temperature information of the temperature sensor array and transmit them to the remote gateway. The gateway transmits the received data to the server through the network port, and the server parses the data and displays it on the page.

[0162] The LoRa module is used as the communication module, and its low power consumption and long-distance transmission characteristics are utilized to solve the problem of high power consumption of traditional wireless communication technology during long-distance transmission. By optimizing the parameter configuration and data rate of the LoRa module, energy consumption is minimized while maintaining long-distance communication. In addition, when there is no data transmission demand, the LoRa device will enter a low-power state, namely sleep mode. At this time, the energy management fusion module and the temperature sensor array have no data to transmit and are in standby mode.

[0163] In this state, the RF part and most of the circuits of the device are in sleep mode, and only the necessary monitoring and wake-up mechanisms are retained. The LoRa device will keep monitoring external events. These external events may include timed wake-up signals and external interrupt signals. Once there is a data transmission requirement or an external event triggers, the device will automatically wake up from sleep mode and enter the working state. Before entering sleep mode, the device may save the current working state, configuration parameters, etc., so that it can quickly restore to the previous working state after waking up.

[0164] This low-power design makes the power consumption of the LoRa module extremely low, generally only a few microamperes of current. The reduced power consumption can achieve long-term stable operation of the device, which is particularly suitable for scenarios that require long-term work and data collection.

[0165] Data management realizes the organic combination of dynamic encryption and permission management system through data management software. Set up routing guards to allocate the operations that users can perform on the front-end page according to their permissions, such as only advanced users can view and modify other users' information. And dynamically determine the encryption method of data according to user permissions. For example, use conventional encryption methods such as AES to encrypt data that ordinary users need to access, and use multiple encryption algorithms for data of advanced users who access highly sensitive data such as operation logs to provide higher security. When the system detects a change in user permissions (for example, the user role is upgraded or specific permissions are revoked), the dynamic encryption system of the software will automatically adjust the data encryption policy related to the user.

[0166] The software also integrates a real-time parameter adjustment and monitoring and early warning linkage system. The software system pre-sets a set of parameter adjustment strategies according to different fault types and equipment status. When the program detects abnormal data, the parameter adjustment module automatically adjusts the working parameters of the equipment according to the scheme in the strategy library. For example, when the data such as the output power of the energy collection module uploaded by the self-powered industrial sensor device to the host computer software is not within the set threshold range, the software will automatically adjust the power output of the energy collection module or set its status to offline sleep state, and send the instruction to the device for execution.

[0167] The front-end page of the software provides a highly interactive data visualization system that allows users to customize the monitoring interface and observe and analyze data in real time through drag and drop, zoom, dynamic charts, etc. Users can create and customize their own dashboards, choose which data to display, and which chart types to use. The front-end page supports the zoom function of the chart. Users can zoom in or out the time axis or value axis to view the data in more detail. You can also view historical data or cross-period data through the scroll function. The charts on the page can be automatically refreshed according to the real-time data source, and users can view the latest monitoring data without manual operation. Support setting refresh intervals or triggering refreshes based on events of data changes.

Claims

1. A self-powered temperature monitoring method for a large generator set, characterized in that: The steps include: Step S01. Capture energy in the environment of magnetic leakage, vibration and temperature difference; (1) In view of the magnetic field environment of large generator sets, electromagnetic elements are used to collect alternating magnetic field energy and convert it into electrical energy based on the principle of electromagnetic induction; (2) In view of the vibration environment of large generator sets, piezoelectric materials and energy harvesting chips are used to collect vibration energy and convert it into electrical energy based on the piezoelectric effect; (3) In view of the temperature difference environment in large-scale generator sets, based on the Seebeck effect, the thermoelectric power generation module uses thermoelectric sheets, which are insulated by filling silica aerogel and equipped with a passive air cooling system to collect the temperature difference energy of the generator set and convert it into electrical energy; Step S02. Stabilize the energy captured from magnetic flux leakage, vibration and temperature difference environment; The three kinds of environmental energy, namely magnetic leakage, vibration and temperature difference, are collected simultaneously and stably output as 3.3V voltage; Step S03. The stabilized energy is subjected to temperature sensing measurement; Step S04: Implement remote control and data management through wireless communication.

2. A self-powered temperature monitoring method for a large generator set according to claim 1, characterized in that: In the case of magnetic leakage environment, a closed coil will generate an induced electromotive force in a three-way alternating magnetic field. Adding a magnetic core will increase the magnetic induction intensity. The output voltage of the coil on the I-shaped magnetic core is the highest. Through the energy collection PCB, the coil is connected to the energy collection PCB input terminal through the input terminal to input energy. The energy collection PCB outputs energy stably to the outside through the remaining two terminals. When the magnetic flux of a closed conductor loop in a magnetic field changes, an induced current is generated in the loop, indicating that an electromotive force ε is induced in the loop. in , and the magnitude of the induced electromotive force is proportional to the rate of change of the magnetic flux ψ with time t; The magnetic flux in the closed loop is: in Represents magnetic induction intensity, which is a vector that describes the distribution of magnetic field in space; Represents a tiny area element, which is a vector whose direction is consistent with the normal direction of the area and whose magnitude is equal to the value of the area; The induced electromotive force of this closed loop is: in Represents the electric field intensity, which is a vector that describes the distribution of the electric field in space; Represents a tiny path element, a vector along the path direction, with a magnitude equal to the path length; We can get: The closed coil loop is static, and the three-way alternating magnetic field linked to it changes with time, which will generate an induced electromotive force: Where x represents a coordinate in space; The core material of the I-shaped magnetic core and the coil is made of 45 steel, and the coil is wound with oxygen-free pure copper enameled wire. Through the energy collection PCB, the piezoelectric sheet, the I-shaped magnetic core and the coil are connected to the energy collection PCB through the terminal, and the energy collection PCB outputs energy to the outside through the terminal.

3. A self-powered temperature monitoring method for a large generator set according to claim 1, characterized in that: In response to the vibration environment, the entire device is connected to the stator of the hydro-turbine generator through the fixing plate of the piezoelectric electromagnetic coupling vibration energy collection device. When the generator starts running, it will generate vibration with a characteristic frequency of 50 Hz. The spring used can resonate at 50 Hz, increasing the original vibration input.

4. A self-powered temperature monitoring method for a large generator set according to claim 3, characterized in that: When the vibration generated by the generator stator drives the transducer cantilever beam to swing up and down, the piezoelectric material attached to the transducer cantilever beam will also be stretched or compressed accordingly to produce deformation. The working mode of the piezoelectric material when collecting vibration energy is d 31 ; d 31 The stress direction of the working mode is 1, and the polarization direction is 3, which are orthogonal. The output of the voltage V and charge Q in the open circuit is expressed as follows: Wherein, σ is stress; g is piezoelectric voltage coefficient; d is piezoelectric coefficient; H is the thickness of the piezoelectric layer, and A is the electrode area; The straight beam type piezoelectric cantilever beam structure in the piezoelectric electromagnetic coupling vibration energy collection device includes a cantilever beam, the cantilever beam is fixed to one end of the substrate, the piezoelectric sheet is fixed on the substrate, and the other end of the substrate is a free end and fixed with a mass block. The resonant frequency of the piezoelectric cantilever beam is changed by adjusting the weight of the mass block, and the piezoelectric sheet is clamped by a clamping structure to make the piezoelectric material deform to generate more energy. When the ambient vibration frequency is close to the natural frequency of the cantilever beam, the output of the piezoelectric sheet increases sharply. The typical value of the vibration frequency of the generator stator is 50Hz, and the bandwidth is extremely narrow. The mass of the mass block at the end of the cantilever beam is adjusted to make the resonant frequency of the cantilever beam consistent with the vibration frequency of the generator stator. The calculation steps of the piezoelectric mass block are as follows: Where m t is the mass of the end counterweight, k is the effective stiffness, f is the resonant frequency, and m is the effective mass; Secondly, the up and down swing of the transducer cantilever beam will drive the electromagnetic transducer at the end to vibrate. Each electromagnetic transducer consists of a magnet barrel, two annular magnets and a copper coil. The two magnets have the same poles facing each other and one of the magnets is fixedly connected to the bottom of the magnet barrel, while the other is not fixed. One of the magnets will be magnetically suspended, and the copper coil is fixedly connected to the magnet barrel. When the magnet barrel vibrates, due to the inertia of the object, the copper coil will cut the magnetic lines of force, and according to the electromagnetic induction phenomenon, electricity will be generated, thus completing the conversion of electromagnetic vibration energy into electrical energy.

5. A self-powered temperature monitoring method for a large generator set according to claim 1, characterized in that: For the temperature difference environment, the two ends of the thermoelectric power generation sheet of the thermoelectric power generation module are the hot end and the cold end of the thermoelectric material itself. When there is a temperature difference at both ends of the thermoelectric power generation sheet, a directional movement of carriers will occur inside it, and eventually a stable electromotive force will be generated, thereby completing the conversion of temperature difference energy into electrical energy.

6. A self-powered temperature monitoring method for a large generator set according to claim 5, characterized in that: The thermoelectric power generation module uses two thermoelectric power generation chips. Each individual terminal can be calculated by Seebeck effect to obtain the theoretical thermoelectric power generation voltage value: In the formula, S AB (T) is the relative Seebeck coefficient on both sides of the thermoelectric power generation sheet, which is a value that changes with temperature and is determined by the thermoelectric material itself. T1 and T2 are the temperature values ​​of the ambient hot end and the ambient cold end respectively; At a certain temperature, the Seebeck coefficient is a certain value, and the above formula can be simplified to: V0=S AB ΔT Where ΔT is the ambient temperature difference, The total power generation voltage of the entire temperature difference power generation module is: V=127×2×V0 =127×2×S AB ΔT。 7. A self-powered temperature monitoring method for a large generator set according to claim 6, characterized in that: The upper and lower ends of the thermoelectric generator are the heat sink and the hot end respectively. The hot end is in direct contact with the ambient heat source, providing a high-temperature environment for the hot end of the thermoelectric generator through solid heat transfer. The heat sink uses aluminum as the heat dissipation material, and the hot end uses copper as the heat transfer material.

8. A self-powered temperature monitoring method for a large generator set according to claim 1, characterized in that: Energy stabilization module is used for energy stabilization. The energy stabilization module adopts the back-end fusion method and the multi-energy fusion method based on graded energy storage, so that leakage magnetic, vibration and temperature difference energy are independently impedance matched and stored, and then the energy is fused and finally output stably. The module uses 3 ADP5091 chips to realize the input of three-way energy. At the same time, super capacitors are used to store the input energy, and then the energy in the super capacitor is stabilized at 3.3V for output through the DC-DC voltage stabilization circuit design. The module has a three-way MPPT DC / DC boost circuit, which is adjusted by the different high and low level states of the REG_D0 and REG_D1 pins. When REG_D1 is at a high level, it can work in boost mode. After the boost conversion, it is directly transmitted to the ADP5091 chip, so that the energy is stored in the supercapacitor, realizing the conversion and stabilization of energy with low input and high output; the module boosts and stabilizes the energy of 80mV~3.3V, and the input power range is 16 microwatts to 600 milliwatts; the open circuit voltage method is adopted, the open circuit voltage is periodically detected through the MTTP pin, and the voltage is adjusted to achieve maximum power point tracking of the three energies; In MPPT =k×V OC The formula is based on the maximum power voltage V MPPT and open circuit voltage V OC The linear relationship of coefficient k is set manually and is between 0.5 and 0.

8. The energy storage device is a supercapacitor. In the constant current charging mode, where I is the constant charging current and the voltage change rate of the supercapacitor is I / C, the voltage across the supercapacitor is: V c0 is the initial voltage of the capacitor, and the charging time is T: Where V cT is the voltage of the supercapacitor at time T; The constant current charging efficiency η is as follows: Where C is the capacitance of the supercapacitor, R ESR is the equivalent internal resistance; The efficiency of constant current charging method is related to charging current I and equivalent internal resistance R ESR As the charging time increases, the higher the initial voltage of the capacitor, the higher the charging efficiency, but the corresponding charging speed is also slower; The multi-energy fusion method based on hierarchical energy storage uses multiple supercapacitors to store the three energies in the subsequent supercapacitors respectively, charging the first-stage supercapacitors, and connecting the subsequent supercapacitors and the first-stage supercapacitors with diodes and low-resistance resistors in series. The stable output of energy adopts the circuit design of LDO low-voltage difference linear regulator, and the energy stored in the first-stage supercapacitor is directly passed through the LDO circuit to achieve stable output of energy; the circuit includes a reference voltage source, a sampling output voltage, an error amplifier and a series adjustment tube. The amplifier is used to control the voltage step-down of the regulator to continuously reach the required output voltage value. The output voltage is divided by the feedback resistor to the input of the error amplifier. When the output voltage is higher than the set value, the internal loop will change the driving voltage to increase the conduction voltage drop of the tube, thereby reducing the output voltage. When the output voltage is higher than the set value, it will in turn increase the output voltage, and finally achieve stable energy output.

9. A self-powered temperature monitoring method for a large generator set according to claim 1, characterized in that: Step S03 is specifically as follows: the sensing temperature measurement part is equipped with an 8-channel interface, an external K-type thermocouple, and supports multi-channel temperature measurement. The module receives power from the energy collection part or an external power supply, and has two interfaces, which are respectively connected to the energy management fusion part and the low-power wireless communication part to wirelessly transmit the measured temperature data to the gateway; multi-channel temperature measurement is based on a temperature measurement chip and two eight-channel multiplexing chips. The eight K-type thermocouples are connected to the temperature measurement chip in turn through the multiplexing chip to realize eight-channel temperature measurement of a single temperature measurement chip.

10. A self-powered temperature monitoring method for a large generator set according to claim 1, characterized in that: In step S04, wireless communication uses LoRa technology to achieve remote data transmission; it is equipped with two interfaces: one interface uses UART protocol for full-duplex serial asynchronous communication, directly connected to the energy management fusion part or the temperature sensor array, to achieve power and temperature data collection and wireless transmission; these data are then sent to the gateway and finally displayed on the server; the other interface is an SMA interface for connecting the antenna; The data management adopts B / S architecture, which includes four parts: monitoring status, monitoring and early warning, equipment parameter adjustment, and system maintenance and management, to achieve real-time monitoring, display and early warning of the rotor temperature of the generator set and online monitoring of the monitoring system and sensor status.

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