Optical Fiber Composite Dynamic Wireless Power Supply Long Rail and In-situ Condition Monitoring System and Method

Abstract

The present invention relates to optical fiber sensing and wireless energy transmission technologies, and particularly to an optical fiber composite dynamic wireless power supply long rail and an in-situ state monitoring system and method. The optical fiber composite dynamic wireless power supply long rail includes a dynamic wireless power supply long rail and an optical fiber sensing system; the dynamic wireless power supply long rail includes a power supply long rail arranged with double-turn Litz wire, with the current directions of the inner and outer Litz wires being opposite, and further includes a transmitting end module and a plurality of receiving end modules located above the track; the optical fiber sensing system includes a first group of fiber Bragg grating strings, a second group of fiber Bragg grating strings, a third group of fiber Bragg grating strings, a fiber Bragg grating demodulator, and a host computer; the first group of fiber Bragg grating strings, the second group of fiber Bragg grating strings, and the third group of fiber Bragg grating strings are respectively laid on the surface of the double Litz wire and are sequentially connected to the fiber Bragg grating demodulator and the host computer; the host computer is connected to the transmitting end module. This system realizes the real-time in-situ monitoring of the internal state variables and transmission state variables of the magnetic coupling mechanism under dynamic working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical fields of optical fiber sensing and wireless energy transmission, and particularly relates to an optical fiber composite dynamic wireless power supply long rail and an in-situ state monitoring system and method therefor. Background Art

[0002] Wireless power transmission technology refers to the realization of energy transmission through the spatial coupling of a magnetic field generated by a high-frequency current without a physical connection between the power supply end and the power receiving end. Compared with the traditional contact charging method, the use of wireless power transmission technology can successfully avoid mechanical wear at the connection caused by repeated plugging and unplugging of charging devices, resulting in poor contact. Based on the magnetic coupling resonance power transmission technology, it can achieve a large transmission power and transmission efficiency at medium and long transmission distances, and is not affected by non-magnetic obstacles in the middle. It is a new type of wireless power transmission technology with broad application prospects.

[0003] Wireless power transmission technology can be divided into static and dynamic wireless power transmission according to whether the relative positions of the power supply end and the power receiving end change during the power transmission process. Dynamic wireless power transmission means that during the wireless power supply process of the power receiving body, there is a relative movement between the power sending end and the receiving end. This method can greatly increase the driving range of vehicles when applied in automated fields such as electric vehicles and intelligent logistics without relying on energy storage rechargeable batteries.

[0004] The magnetic coupling mechanism is the core of electromagnetic conversion for dynamic wireless power transmission of electric vehicles. When performing high-power transmission, it has problems such as energy loss, heating, and deformation. A common method is to add electrical sensors to monitor the state of the magnetic coupling mechanism in real time, feedback to the excitation power supply and the control center, and adjust the excitation source to form a closed-loop control to ensure the normal and stable operation of the wireless power supply magnetic coupling mechanism.

[0005] The transmission performance of the magnetic coupling mechanism is vulnerable to dynamic coupling and load time-varying parameter interference during vehicle operation, resulting in a shift in the resonant point frequency of the system, which easily causes an increase in the reactive current component in the resonant cavity and seriously affects the system transmission performance. The magnetic coupling transmission state can be identified by using a magnetic field sensor, and then the closed-loop control can be used to achieve the efficient operation of the system. Traditional electrical electromagnetic field sensors have high electrical insulation requirements when measuring in a strong electromagnetic environment, and have problems such as limited response bandwidth and dynamic measurement range.

[0006] Compared with electrical electromagnetic field sensors, optical sensors have the advantages of good insulation performance, strong anti-interference ability, fast response speed, and high safety, and have great application potential in a strong electromagnetic environment. The typical structure of an optical electromagnetic field sensor is composed of a fiber grating combined with an electro- or magnetostrictive element, which is suitable for measuring temperature and stress in a strong electromagnetic field, and has high sensitivity and reliability. Summary of the Invention

[0007] Real-time monitoring of the magnetic coupling mechanism state is the key to realizing the safe and reliable operation of dynamic wireless power supply for electric vehicles. Aiming at the deficiencies that it is difficult to obtain the internal state variables of the current power transmission coupling mechanism and the resonance transmission state identification is vulnerable to interference, the present invention proposes a long-rail dynamic wireless power supply platform that can in-situ monitor and calculate the physical state of a wireless power supply system (especially the magnetic coupling mechanism).

[0008] To solve the above technical problems, the present invention adopts the following technical solutions: a fiber-optic composite dynamic wireless power supply long rail and in-situ state monitoring system. The fiber-optic composite dynamic wireless power supply long rail includes an integrated dynamic wireless power supply long rail and a fiber-optic sensing system; the dynamic wireless power supply long rail includes a power supply long rail arranged with double-turn Litz wire, the current directions of the inner and outer Litz wires are opposite, and it also includes a transmitting end module and a plurality of receiving end modules located above the track; the transmitting end module includes a high-frequency inverter power supply, a transmitting end magnetic coupling mechanism, and a transmitting end compensation network; the receiving end module includes a receiving end magnetic coupling mechanism, a receiving end compensation network, a rectifying and voltage-regulating module, and a load; the transmitting end coupling mechanism and the transmitting end compensation network form a resonant circuit, and the high-frequency inverter power supply supplies power to its resonant circuit; the receiving end magnetic coupling mechanism and the receiving end compensation network form a resonant circuit, the rectifying and voltage-regulating module is connected to the receiving end magnetic coupling mechanism, and the rectifying and voltage-regulating module is connected to the load;

[0009] The fiber-optic sensing system includes a first group of fiber Bragg grating strings, a second group of fiber Bragg grating strings, a third group of fiber Bragg grating strings, a fiber Bragg grating demodulator, and a host computer; the first group of fiber Bragg grating strings, the second group of fiber Bragg grating strings, and the third group of fiber Bragg grating strings are respectively laid on the surface of the double Litz wire and are sequentially connected to the fiber Bragg grating demodulator and the host computer; the host computer is connected to the high-frequency inverter power supply.

[0010] In the above fiber-optic composite dynamic wireless power supply long rail and in-situ state monitoring system, the first group of fiber Bragg grating strings is laid on the top of the two Litz wires, the second group of fiber Bragg grating strings is laid on the inner side of the two Litz wires, and the third group of fiber Bragg grating strings is laid at the bottom of the two Litz wires near the ferrite.

[0011] A monitoring method for a fiber-optic composite dynamic wireless power supply long rail and in-situ state monitoring system. The optical path module in the fiber Bragg grating demodulator emits laser light to each group of fiber Bragg grating strings. The laser light undergoes total internal reflection in each group of fiber Bragg grating strings. The reflected light passes through the position where the fiber Bragg grating strings are laid. After the optical signal acquisition module in the fiber Bragg grating demodulator extracts the reflected light information, the data processing module performs joint decoupling calculation on the wavelengths of multiple groups of reflected light to solve the temperature and stress changes of the dynamic wireless power supply long rail, and transmits them to the host computer for visual analysis and real-time control.

[0012] In the monitoring method of the above fiber-optic composite dynamic wireless power supply long rail and in-situ state monitoring system, the monitoring method specifically includes:

[0013] The high-frequency inverter power supply provides direct current and converts it into high-frequency alternating current to power the resonant circuit composed of the transmitting-end magnetic coupling mechanism and the transmitting-end compensation network;

[0014] The transmitting-end magnetic coupling mechanism and the transmitting-end compensation network form a resonant circuit to transmit energy to the receiving-end magnetic coupling mechanism;

[0015] The receiving-end magnetic coupling mechanism and the receiving-end compensation network form a resonant circuit to receive the energy transmitted by the transmitting-end magnetic coupling mechanism and generate high-frequency alternating current with the same current frequency as that in the transmitting-end magnetic coupling mechanism;

[0016] The rectifying and voltage-regulating module rectifies the high-frequency alternating current in the receiving-end magnetic coupling mechanism into direct current and reduces the voltage to the charging voltage through the rectifying and voltage-regulating module;

[0017] The fiber Bragg grating string is laid on the surface of the Litz wire to obtain the state information of the transmitting-end magnetic coupling mechanism and transmit it to the fiber Bragg grating demodulator;

[0018] The fiber Bragg grating demodulator, as the optical information receiving unit and processing unit, demodulates and models the information transmitted by the optical fiber and then transmits it to the upper computer for analysis;

[0019] The upper computer visually analyzes the information transmitted by the fiber Bragg grating demodulator, obtains the internal state information and transmission state information of the transmitting-end magnetic coupling mechanism, and sends a control signal to the high-frequency inverter power supply to regulate the power output of the transmitting-end magnetic coupling mechanism; during the dynamic wireless power supply process, it continuously monitors the state information of the transmitting-end magnetic coupling mechanism, and according to the established mapping law of thermal-mechanical-magnetic optical path physical quantities, analyzes the numerical model between the high-frequency coupling magnetic field intensity, frequency and the wavelength changes of multiple groups of gratings on the long track, and obtains the recursive parameter law between the coupling magnetic field intensity and the fiber temperature rise value to identify the position of the receiving-end magnetic coupling mechanism in real time.

[0020] In the monitoring method of the above fiber composite dynamic wireless power supply long track and in-situ state monitoring system, the first group of fiber Bragg grating strings laid on the top of the two Litz wires is used for monitoring the extrusion stress and detecting abnormal deformation of the system, as well as measuring the temperature rise at the top of the wire caused by the skin effect; the second group of fiber Bragg grating strings laid inside the two Litz wires is used for monitoring the temperature rise caused by the proximity effect between the wires; the third fiber Bragg grating string arranged at the bottom of the two Litz wires is used for monitoring the temperature rise caused by the ferrite loss.

[0021] In the monitoring method of the above-mentioned fiber composite dynamic wireless power supply long rail and in-situ state monitoring system, according to the functional relationship between the grating wavelength in the fiber Bragg grating string and stress and temperature, the temperature and stress change amounts are extracted for each grating; the first group of fiber Bragg grating strings, the second group of fiber Bragg grating strings, and the third group of fiber Bragg grating strings establish a wavelength equation to solve, realizing the decoupling of temperature and stress in the wavelength function formula, and then respectively solving the state quantity information.

[0022] In the monitoring method of the above-mentioned fiber composite dynamic wireless power supply long rail and in-situ state monitoring system, aiming at the mechanical characteristics and grating transmission characteristics of the fusion-type fiber Bragg grating string, based on the electromagnetic induction law and the ferrite loss and Litz wire high-frequency loss formulas, Comsol or other multi-physics field coupling simulation software is used to explore the hot spot distribution of the coupling mechanism. According to the positions of the points with the maximum magnetic field intensity and magnetic induction intensity in the simulation results, a suitable grating fusion form and laying method are selected as the carrier for system state monitoring.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention realizes the in-situ monitoring of the thermal-mechanical-magnetic multi-variables of the magnetic coupling mechanism of the dynamic wireless power supply long rail, breaking through the bottleneck of accurately and real-time monitoring the internal and transmission states of the magnetic coupling mechanism. By studying the influence of the fiber laying method and material characteristics on energy transmission and magnetic field detection, a composite fiber structure of the transmitting-end magnetic coupling mechanism suitable for different power and packaging requirements is obtained, and a sensing method for constructing the magnetic coupling mechanism and its internal state by the fiber composite conductor is proposed, realizing the accurate and real-time monitoring of the thermal-mechanical-magnetic multi-variables of the dynamic wireless power supply long rail. The present invention overcomes the difficulties that the energy loss, heating, and deformation of the existing dynamic wireless power supply platform cannot be monitored during high-power transmission, and realizes the real-time in-situ monitoring of the internal state quantity and transmission state quantity of the magnetic coupling mechanism under dynamic conditions. Moreover, there is a high tolerance for the position offset between the transmitting end and the receiving end, and it can be applied to complex industrial environments with high dynamics and disturbances. It can be extended to dynamic wireless power supply scenarios for industrial mobile devices such as intelligent logistics equipment and electric vehicles to ensure the normal operation of the magnetic coupling system. Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of the fiber composite dynamic wireless power supply long rail according to an embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of the distribution and function description of the fiber Bragg grating string according to an embodiment of the present invention;

[0026] Figure 3 is a schematic diagram of the process of simultaneous decoupling of the wavelength functions of multiple groups of gratings according to an embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of hot spot calculation and positioning of the fiber composite dynamic wireless power supply long rail according to an embodiment of the present invention;

[0028] Figure 5 It is a schematic diagram of an embodiment of the optical fiber composite dynamic wireless power supply long rail structure and the in-situ state monitoring method in the embodiments of the present invention. Specific embodiments

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0030] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0031] The present invention will be further described below in conjunction with specific embodiments, but it is not a limitation of the present invention.

[0032] An optical fiber composite dynamic wireless power supply long rail and in-situ state monitoring system in this embodiment is applicable to the monitoring of the temperature and stress of a dynamic wireless power supply system. The monitoring system in this embodiment can overcome the difficulties that the existing dynamic wireless power supply platform cannot monitor the energy loss, heating, and deformation during high-power transmission, and realize the real-time in-situ monitoring of the internal state variables and transmission state variables of the magnetic coupling mechanism under dynamic conditions.

[0033] The monitoring system includes an optical fiber sensing system and a long rail dynamic wireless power supply system. The optical fiber sensing system includes an optical fiber grating string embedded in the magnetic coupling mechanism, an optical fiber grating demodulator, and a host computer. The optical fiber grating string is used to obtain state variable information such as the internal temperature of the magnetic coupling mechanism and transmission state information; the demodulator emits laser light to the optical fiber and captures the reflected light passing through the optical fiber grating string. Through modeling and calculation, the changes in multiple state variables of the coupling mechanism are obtained, and finally transmitted to the host computer for visual analysis and real-time control. The long rail dynamic wireless power supply transmitter adopts an inner and outer double-turn Litz wire design. The current flow directions of the inner and outer wires are opposite to strengthen the magnetic field intensity above the rail. Each turn of the wire is integrated with three optical fiber grating strings and laid on the top, inside, and near the ferrite of the wire.

[0034] This embodiment is achieved through the following technical solutions. A fiber composite dynamic wireless power supply long rail and in-situ condition monitoring system, where the fiber composite dynamic wireless power supply long rail includes an integrated dynamic wireless power supply long rail and a fiber optic sensing system; the dynamic wireless power supply long rail includes a power supply long rail arranged with double-turn Litz wire, with the current directions of the inner and outer Litz wires being opposite, and also includes a transmitting end module and multiple receiving end modules located above the track; the transmitting end module includes a high-frequency inverter power supply, a transmitting end magnetic coupling mechanism, and a transmitting end compensation network; the receiving end module includes a receiving end magnetic coupling mechanism, a receiving end compensation network, a rectifying and voltage regulating module, and a load; the transmitting end coupling mechanism and the transmitting end compensation network form a resonant circuit, and the high-frequency inverter power supply supplies power to its resonant circuit; the receiving end magnetic coupling mechanism and the receiving end compensation network form a resonant circuit, the rectifying and voltage regulating module is connected to the receiving end magnetic coupling mechanism, and the rectifying and voltage regulating module is connected to the load;

[0035] The fiber optic sensing system includes a first group of fiber Bragg grating strings, a second group of fiber Bragg grating strings, a third group of fiber Bragg grating strings, a fiber Bragg grating demodulator, and a host computer; the first group of fiber Bragg grating strings, the second group of fiber Bragg grating strings, and the third group of fiber Bragg grating strings are respectively laid on the surface of the double Litz wire and are sequentially connected to the fiber Bragg grating demodulator and the host computer; the host computer is connected to the high-frequency inverter power supply.

[0036] The specific functions of each module are as follows:

[0037] High-frequency inverter power supply: Provides direct current and converts it into high-frequency alternating current to supply power to the resonant circuit composed of the transmitting end magnetic coupling mechanism and the transmitting end compensation network. Transmitting end magnetic coupling mechanism: Forms a resonant circuit with the transmitting end compensation network to transmit energy to the receiving end magnetic coupling mechanism. Transmitting end compensation network: Forms a resonant circuit with the transmitting end magnetic coupling mechanism. Receiving end magnetic coupling mechanism: Forms a resonant circuit with the receiving end compensation network to receive the energy transmitted by the transmitting end magnetic coupling mechanism and generate high-frequency alternating current with the same frequency as the current in the transmitting end magnetic coupling mechanism. Receiving end compensation network: Forms a resonant circuit with the receiving end magnetic coupling mechanism. Rectifying and voltage regulating module: Rectifies the high-frequency alternating current in the receiving end magnetic coupling mechanism into direct current, steps down the voltage through the voltage regulating module to the charging voltage, and ensures that the charging voltage fluctuates little.

[0038] The optical fiber sensing system includes: a fiber Bragg grating string composited with the transmitting end magnetic coupling mechanism, a fiber Bragg grating demodulator and a host computer. The fiber Bragg grating string: laid on the surface of the Litz wire of the transmitting end magnetic coupling mechanism, obtains the state information of the transmitting end magnetic coupling mechanism, and transmits it to the fiber Bragg grating demodulator; the fiber Bragg grating demodulator: as an optical information receiving unit and processing unit, demodulates and models the information transmitted by the optical fiber and transmits it to the host computer for analysis. The host computer: visualizes and analyzes the information transmitted by the fiber Bragg grating demodulator, obtains the internal state information and transmission state information of the transmitting end magnetic coupling mechanism, and can send control signals to the high-frequency inverter power supply to regulate the power output of the magnetic coupling mechanism. In addition, the host computer can continuously monitor the state information of the transmitting end magnetic coupling mechanism during the dynamic wireless power supply process, and analyzes the numerical model between the long track high-frequency coupling magnetic field intensity, frequency and multiple groups of grating wavelength changes according to the established thermal-mechanical-magnetic optical path physical quantity mapping law, and obtains the recursive parameter law between the coupling magnetic field intensity and the fiber temperature rise value, so as to identify the position of the receiving end magnetic coupling mechanism in real time.

[0039] In this embodiment, the fiber grating string is laid on the surface of the Litz wire. This is because the transmission power inside the wire is too large under certain working conditions, which can easily cause changes in the internal structure of the optical fiber and damage the original physical properties. If the fiber grating string is embedded in the magnetic coupling mechanism, the excessive transmitting coil current may affect the grating period and the grating center wavelength, which will have a great impact on the monitoring accuracy of multiple physical quantities. The fiber grating strings laid on the surface of the Litz wire are laid on the top of the wire, the vertical section inside the wire, and the bottom. Among them, the grating laid on the top of the wire is more sensitive to stress changes, which can be used to monitor the extrusion stress and detect abnormal deformation of the system in time. It can also measure the temperature rise at the top of the wire caused by the skin effect; the grating located on the vertical section inside the wire can monitor the temperature rise caused by the proximity effect between the wires; the grating arranged at the bottom of the conductor can monitor the temperature rise caused by ferrite loss because it is close to the ferrite. At the same time, the three groups of fiber grating strings can improve the measurement cost by evenly and alternately laying the gratings.

[0040] There is a functional relationship between the grating wavelength, stress and temperature in the fiber grating string, and each fiber grating string can capture the temperature and stress changes. The top grating, vertical section grating, and bottom grating located on the same vertical section can be solved by the wavelength equation to achieve the decoupling of temperature and stress in the wavelength function, and then solve the state quantity information separately.

[0041] In view of the mechanical properties and grating transmission characteristics of the fused fiber Bragg grating string, this embodiment is based on the law of electromagnetic induction and the formulas of ferrite loss and Litz wire high-frequency loss, combined with the typical fiber-optic composite dynamic wireless power supply long rail layout in this embodiment, and uses Comsol or other multi-physical field coupling simulation software to explore the hot spot distribution of the coupling mechanism. According to the location of the maximum points of magnetic field intensity and magnetic induction intensity in the simulation results, the appropriate grating fusion form and laying method are flexibly selected as the carrier for system status monitoring.

[0042] The specific implementation process of an in-situ state monitoring method of this embodiment is as follows: the fiber Bragg grating demodulator is used as a light source excitation and optical polarization signal receiving and processing unit. First, the fiber Bragg grating demodulator optical path module emits laser to the fiber Bragg grating string coupled to its interface. The laser is totally reflected in the optical fiber, and reflected light passes through the position where the fiber Bragg grating string is laid. The optical signal acquisition module in the fiber Bragg grating demodulator captures the reflected light information and then uses the data processing module to perform joint decoupling calculations on the reflected light wavelength, thereby solving the temperature and stress changes of the dynamic wireless power supply long rail, and finally transmitting it to the host computer for visual analysis and real-time regulation.

[0043] This embodiment continuously monitors the internal and external state information of the magnetic coupling mechanism of the transmitter during the dynamic wireless power supply process, and identifies the position of the receiving end by parsing the internal and external state information through the host computer. At the same time, the host computer transmits a control signal to adjust the voltage and frequency of the high-frequency AC power supply based on the identification result of the receiving end position, thereby affecting the power supply of the transmitter and achieving the optimal solution for the transmission power and efficiency of the coupling mechanism of the receiving end. When the receiving end moves relative to the transmitting end, high-energy-efficiency transmission can still be maintained, and there is a high tolerance for position offset between the transmitting end and the receiving end. Therefore, this embodiment can be applied to complex industrial environments with high dynamics and disturbances.

[0044] When implementing it, Figure 1 As shown, the optical fiber composite dynamic wireless power supply long rail and the in-situ state monitoring system, the optical fiber composite dynamic wireless power supply long rail includes an integrated dynamic wireless power supply long rail and an optical fiber sensing system; the dynamic wireless power supply long rail includes a power supply long rail set with double turns of Litz wire, the inner and outer Litz wires have opposite current directions, and also includes a transmitting end module and a plurality of receiving end modules located above the rail; the transmitting end module includes a high-frequency inverter power supply, a transmitting end magnetic coupling mechanism and a transmitting end compensation network; the receiving end module includes a receiving end magnetic coupling mechanism, a receiving end compensation network, a rectifier and a load; the transmitting end coupling mechanism and the transmitting end compensation network form a resonant circuit, and the high-frequency inverter power supply supplies power for the resonant circuit; the receiving end magnetic coupling mechanism and the receiving end compensation network form a resonant circuit, the rectifier and the voltage regulator module are connected to the receiving end magnetic coupling mechanism, and the rectifier and the voltage regulator module are connected to the load;

[0045] The optical fiber sensing system includes a first group of optical fiber Bragg grating strings, a second group of optical fiber Bragg grating strings, a third group of optical fiber Bragg grating strings, an optical fiber Bragg grating demodulator and a host computer; the first group of optical fiber Bragg grating strings, the second group of optical fiber Bragg grating strings and the third group of optical fiber Bragg grating strings are respectively laid on the surface of the double Litz wire, and are connected to the optical fiber Bragg grating demodulator and the host computer in sequence; the host computer is connected to a high-frequency inverter power supply.

[0046] like Figure 2 As shown, three groups of fiber grating strings are laid on the top, inside and near the ferrite of two conductors respectively. The fiber grating string located at the top of the conductor is more sensitive to stress changes. In addition to measuring the temperature rise caused by the skin effect, it can also capture stress information; the fiber grating string located at the vertical section of the conductor is used to collect temperature rise information caused by the proximity effect; the fiber grating string located at the bottom of the conductor is close to the ferrite and is used to monitor the heat caused by ferrite loss. At the same time, the three groups of fiber grating strings can improve the measurement cost by evenly and alternately laying gratings. In this embodiment, the fiber grating string is laid on the surface of the Litz wire. This is because under certain working conditions, the transmission power inside the conductor is too large, which can easily cause changes in the internal structure of the optical fiber and damage the original physical properties. If the fiber grating string is embedded in the magnetic coupling mechanism, the excessive transmitting coil current may affect the grating period and the grating center wavelength, which will greatly affect the monitoring accuracy of multiple physical quantities.

[0047] like Figure 3 As shown in the figure, there is a functional relationship between the grating wavelength, stress and temperature in the fiber grating string, and each grating can capture the temperature and stress changes. The top grating, vertical section grating, and bottom grating located in the same vertical section can be solved by the wavelength equation to achieve the decoupling of temperature and stress in the wavelength function, and then solve the state quantity information separately.

[0048] like Figure 4 As shown, for the mechanical properties and grating transmission characteristics of the fusion-spliced fiber Bragg grating string, this embodiment is based on the law of electromagnetic induction and the formulas for ferrite loss and Litz wire high-frequency loss, combined with the typical fiber-optic composite dynamic wireless power supply long rail layout in this embodiment, and uses Comsol or other multi-physics field coupling simulation software to explore the hot spot distribution of the coupling mechanism. According to the locations of the maximum points of magnetic field intensity and magnetic induction intensity in the simulation results, the appropriate grating fusion form and laying method are flexibly selected as the carrier for system status monitoring.

[0049] Examples:

[0050] The fiber diameter is selected as 125 μm, and the reflectivity is 92% (to ensure that the optical signal after the group peak algorithm is strong enough). The specification of the Litz wire used for winding the magnetic coupling mechanism at the wireless power supply transmitter end of the long track is 0.1 * 1200 mm, and the wire diameter is about 5 mm. In the specific preparation process, through devices such as an optical fiber fusion splicer, an optical fiber grating string is laid on the surface of each enameled Litz wire. Each optical fiber grating has multiple groups of gratings, and an fc / apc optical fiber jumper connector is provided in the optical fiber pigtail.

[0051] At the same time, considering the requirements of energy transmission and environmental characteristics, and taking into account the mechanical properties of the composite optical fiber, based on the measurement of the mechanical strength, electromagnetic performance, and optical performance of the optical fiber grating string under various processes, an appropriate structure and preparation process can be selected to fabricate an optical fiber grating string that adapts to different working conditions and measurement ranges.

[0052] The method for obtaining internal state information (temperature, strain) is as follows:

[0053] In this example, multiple fiber Bragg gratings are used to measure the temperature change and strain of the magnetic coupling mechanism. When broadband light travels in the optical fiber, the wavelength of the transmitted light reflected back at the center of the grating is a function of both temperature T and strain ε. Therefore, by measuring the center wavelength of the grating, the temperature field and strain field of the magnetic coupling mechanism can be inversely deduced. Then, by expanding the temperature and strain correlation function of the Bragg wavelength at (ε0, T0) and ignoring the high-order terms and cross-terms above the second order, the Bragg wavelength function is linearly simplified. And a correction method is proposed to reduce the detection error caused by ignoring the cross-sensitivity term of stress and temperature. Finally, the coupled linear influence of axial strain and temperature is separated, and a fiber composite conductor structure with temperature compensation is considered to minimize the change in the center wavelength of the grating caused by temperature drift. In this example, a temperature compensation fiber structure is established on the single-mode optical fiber grating string to ensure that it is not affected by strain and only reflects the change in the temperature field, thereby separating the influence of temperature on the offset of the center wavelength of the grating and further inferring the magnitude of the strain suffered by the magnetic coupling mechanism, realizing the precise perception of the internal state of the magnetic coupling mechanism.

[0054] As Figure 5 shown, the technical solution of this embodiment will be further specifically described below through a specific example of in-situ monitoring of fiber composites.

[0055] A long-track-shaped dynamic wireless power supply system is set up, using a double-turn Litz wire design on the inner and outer sides. The current flow directions of the inner and outer wires are opposite to strengthen the magnetic field intensity above the track, as Figure 5 shown. It mainly consists of a transmitting coil Tx, a receiving coil Rx, and a ferrite. The specific parameters are: the length of the straight part of the guide rail l = 2000 mm, and the radius r of the semi-circular part of the guide rail T= 500 mm, the distance g between the guide rail and the transmitting coil is 50 mm, and the diameter t of the transmitting coil w = 5 mm. A ferrite is provided below the guide rail to reduce magnetic leakage, and its width is w f = 80 mm, and the thickness is t f = 2.5 mm, and the radius of the receiving coil is r R = 150 mm. The DC power supply U in passes through an inverter and is connected in series with a compensation capacitor to form an alternating current, serving as the power supply transmitting end in the guide rail circuit, and forming a current magnitude I in the transmitting coil tx = 20 A. The gap distance between the Tx and Rx coils is 20 mm. The operating frequency of the entire dynamic wireless power supply system is 85 kHz. Fiber optic composite materials are inserted at different positions on the winding wire for temperature measurement. At the same time, the information collected by the optical fiber is transmitted to the fiber Bragg grating demodulator. The fiber Bragg grating demodulator decouples and analyzes the received grating center wavelength information, and then transmits the resolved temperature and stress digital quantity information to the host computer to be converted into analog quantity information and visualized

[0056] Due to the power losses in the winding and the ferrite, the temperature of the transmitting coil will increase. The winding losses include ohmic losses and high-frequency losses. The high-frequency losses are mainly related to the skin effect and the proximity effect. The losses in the ferrite are caused by the induced eddy currents from the winding magnetic field. Therefore, for the specific heating points of the transmitting coil, three groups of fiber Bragg grating strings are set in the fiber optic composite conductor, respectively located at: near the ferrite, at the vertical cross-section of the wire, and at the top of the wire. Among them, the fiber near the ferrite is used to monitor the hot spots near the ferrite and the extrusion stress received at the bottom of the wire. The fibers at the vertical cross-section of the wire and at the top of the wire monitor the hot spots of the wire. The fiber at the top of the wire can monitor the external metal foreign objects and the hot spots caused by the skin effect. Through simulation analysis, the maximum magnetic field intensity and the maximum magnetic induction intensity points of the dynamic wireless power supply long rail are located at the top of the wire and at the gap between the ferrite and the wire, respectively. According to the calculation formulas of ferrite losses, skin effect, and proximity effect, the bottom and top of the wire are suspected hot spots. Therefore, more fiber Bragg grating strings should be set at the top and bottom to monitor the operating state of the magnetic coupling mechanism. In addition, the electric field and temperature near the coil inflection point are relatively high, and more fiber Bragg grating strings can be set for local state monitoring

[0057] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention accordingly. For those skilled in the art, it should be able to realize that all the equivalent replacements and obvious changes made by using the content of the specification of the present invention should be included in the protection scope of the present invention

Claims

1. Monitoring method for a long rail with fiber composite dynamic wireless power supply and in-situ condition monitoring system, the monitoring system comprising: The fiber-optic composite dynamic wireless power supply long rail includes a dynamic wireless power supply long rail and a fiber-optic sensing system; The dynamic wireless power supply long rail includes a power supply long rail arranged with double-turn Litz wire, where the current directions of the inner and outer Litz wires are opposite, and also includes a transmitting end module and multiple receiving end modules located above the track; the transmitting end module includes a high-frequency inverter power supply, a transmitting end magnetic coupling mechanism, and a transmitting end compensation network; the receiving end module includes a receiving end magnetic coupling mechanism, a receiving end compensation network, a rectifying and voltage-regulating module, and a load; the transmitting end coupling mechanism and the transmitting end compensation network form a resonant circuit, and the high-frequency inverter power supply supplies power to its resonant circuit; the receiving end magnetic coupling mechanism and the receiving end compensation network form a resonant circuit, the rectifying and voltage-regulating module is connected to the receiving end magnetic coupling mechanism, and the rectifying and voltage-regulating module is connected to the load; the fiber-optic sensing system includes a first group of fiber Bragg grating strings, a second group of fiber Bragg grating strings, a third group of fiber Bragg grating strings, a fiber Bragg grating demodulator, and a host computer; the first group of fiber Bragg grating strings, the second group of fiber Bragg grating strings, and the third group of fiber Bragg grating strings are respectively laid on the surfaces of the inner and outer double Litz wires and are sequentially connected to the fiber Bragg grating demodulator and the host computer; the host computer is connected to the high-frequency inverter power supply; the first group of fiber Bragg grating strings is laid on the tops of the two Litz wires, the second group of fiber Bragg grating strings is laid on the inner sides of the two Litz wires, and the third group of fiber Bragg grating strings is laid at the bottom near the ferrite of the two Litz wires; it is characterized in that the monitoring method includes that the optical path module in the fiber Bragg grating demodulator emits laser to each group of fiber Bragg grating strings, the laser undergoes total internal reflection in each group of fiber Bragg grating strings, the reflected light passes through the position where the fiber Bragg grating strings are laid, and after the optical signal acquisition module in the fiber Bragg grating demodulator extracts the reflected light information, the data processing module performs simultaneous decoupling calculation on the wavelengths of multiple groups of reflected light to solve the temperature and stress changes of the dynamic wireless power supply long rail and transmits them to the host computer for visual analysis and real-time control.

2. The monitoring method of the long rail and in-situ state monitoring system based on optical fiber composite dynamic wireless power supply according to claim 1, characterized in that, The specific monitoring method includes: The high-frequency inverter power supply provides direct current and converts it into high-frequency alternating current to supply power to the resonant circuit composed of the transmitting end magnetic coupling mechanism and the transmitting end compensation network; The transmitting end magnetic coupling mechanism and the transmitting end compensation network form a resonant circuit to emit energy to the receiving end magnetic coupling mechanism; The receiving end magnetic coupling mechanism and the receiving end compensation network form a resonant circuit to receive the energy emitted by the transmitting end magnetic coupling mechanism and generate high-frequency alternating current with the same current frequency as that in the transmitting end magnetic coupling mechanism; The rectifying and voltage-regulating module rectifies the high-frequency alternating current in the receiving end magnetic coupling mechanism into direct current and reduces the voltage to the charging voltage through the rectifying and voltage-regulating module; The fiber Bragg grating strings are laid on the surface of the Litz wire to obtain the state information of the transmitting end magnetic coupling mechanism and transmit it to the fiber Bragg grating demodulator; The fiber Bragg grating demodulator, as an optical information receiving unit and processing unit, demodulates and models the information transmitted by the optical fiber and then transmits it to the host computer for analysis; The host computer visually analyzes the information transmitted by the fiber Bragg grating demodulator, obtains the internal state information and transmission state information of the magnetic coupling mechanism at the transmitting end, and sends a control signal to the high-frequency inverter power supply to regulate the power output of the magnetic coupling mechanism at the transmitting end; during the dynamic wireless power supply process, continuously monitor the state information of the magnetic coupling mechanism at the transmitting end, and according to the established mapping law of thermal-mechanical-magnetic optical path physical quantities, analyze the numerical model between the high-frequency coupling magnetic field intensity, frequency and the wavelength changes of multiple groups of gratings, and obtain the recursive parameter law between the coupling magnetic field intensity and the fiber temperature rise value, so as to identify the position of the magnetic coupling mechanism at the receiving end in real time.

3. The monitoring method of the optical fiber composite dynamic wireless power supply long rail and in-situ state monitoring system according to claim 2, characterized in that, The first group of fiber Bragg grating strings laid on the top of two Litz wires is used for monitoring extrusion stress, detecting system abnormal deformation, and measuring the temperature rise at the top of the wire caused by the skin effect; the second group of fiber Bragg grating strings laid on the inner side of two Litz wires is used for monitoring the temperature rise caused by the proximity effect between the wires; the third fiber Bragg grating string arranged at the bottom of two Litz wires is used for monitoring the temperature rise caused by ferrite loss.

4. The monitoring method of the optical fiber composite dynamic wireless power supply long rail and in-situ state monitoring system according to claim 3, characterized in that, According to the functional relationship between the grating wavelength and stress and temperature in the fiber Bragg grating string, the temperature and stress change amounts are extracted for each grating; the first group of fiber Bragg grating strings, the second group of fiber Bragg grating strings and the third group of fiber Bragg grating strings establish a wavelength equation to solve, realize the decoupling of temperature and stress in the wavelength function formula, and then solve the state quantity information respectively.

5. The monitoring method of the optical fiber composite dynamic wireless power supply long rail and in-situ state monitoring system according to claim 2, characterized in that, Aiming at the mechanical characteristics and grating transmission characteristics of the fusion-type fiber Bragg grating string, based on the electromagnetic induction law and the ferrite loss and Litz wire high-frequency loss formulas, use Comsol or multi-physics field coupling simulation software to explore the hot spot distribution of the coupling mechanism, and select the appropriate grating fusion form and laying method according to the positions of the points with the maximum magnetic field intensity and magnetic induction intensity in the simulation results as the carrier for system state monitoring.

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