De-icing system and control

Abstract

The present invention relates generally to methods and systems for heating the outer surface of a bulk medium such as an aircraft. An exemplary system includes a series of individual heating elements, sensors, and a control system. The heating elements are arranged on the skin of the aircraft. The sensors are located on the skin in positions corresponding to relatively low temperature areas within the heating pattern produced by the heating elements. The control system is connected to the heating elements and the sensors. The control system is configured to control the power supplied to the heating elements in response to output from the sensors.

Description

Technical Field

[0001] This specification relates to heating systems used with conductive materials. Background Technology

[0002] Many conductive surfaces (such as those on automobiles, aircraft, and satellites) are exposed to cold and icing conditions during daily use. Ice or water buildup on the conductive surfaces of these structures can lead to inefficient or unsafe operating conditions. For example, ice buildup on aircraft wings can result in reduced lift and increased drag.

[0003] Many of these structures either lack a heating system or require a heating system that necessitates the use of large electronic or other equipment. The use of such large installations poses a challenge to the industry. Summary of the Invention

[0004] This specification describes techniques for heating conductive surfaces. These techniques generally involve using a high-frequency alternating current (“AC”) signal (e.g., above 1 kHz) to shape the current density in a target area of ​​a conductive bulk medium (e.g., a conductive material), thereby causing Joule heating of the medium.

[0005] Joule heating (also known as ohmic heating or resistance heating) is the process by which an electric current generates heat when it passes through a conductor. The heat generated by the conductive medium is based on the amount of current flowing through it and the resistance of the medium. Therefore, heating can be controlled (e.g., increased or decreased) by adjusting the current, voltage, resistance, or a combination thereof.

[0006] The resistance of a conductor can be increased by constraining the volume within which current can flow and increasing the length of the current flow. Implementation of the invention can be configured to generate heating in a bulk medium by manipulating mechanisms for shaping (e.g., contracting, elongating, etc.) the current within the conductive medium: for example, by using the skin effect and the proximity effect. Both effects rely on passing a high-frequency AC current through the conductive medium to be heated. The skin effect constrains current flow by taking advantage of the tendency of alternating current distribution within the conductor, such that the current density increases near the conductor surface and decreases with increasing depth within the conductor. The proximity effect can be used to further constrain current flow in the conductor by placing another AC current path near the existing current flowing in the conductor. The proximity effect can also be used to elongate the current path.

[0007] For example, an implementation of the invention is configured to increase the resistance of the bulk medium along the current path through the medium by contracting the current flow along the path. Therefore, this implementation can provide increased heating performance in the conductive medium while allowing a reduction in the current required to generate heat. That is, by increasing the effective resistance of the conductive medium along a specific current path, the current required to generate Joule heating in the medium will be less than that required by other methods.

[0008] The subject matter described in this specification can be implemented to achieve one or more of the following advantages: Conductors can be heated using a lighter, less bulky electrical system. Additionally, heating can be localized to a target area without overheating the heating system circuitry. The heating system can be more efficient, for example, by generating heat directly in the bulk medium (e.g., an aircraft wing) itself, rather than in heating elements or layers attached to the bulk medium. The system can also use less current and voltage for heating, which may improve safety and reliability. In some implementations, component stress can also be reduced. System installation or retrofitting can be easier, faster, or cheaper. System maintenance can be cheaper or easier. The system can be non-invasive when retrofitted to an existing system. The system can be de-iced faster.

[0009] One or more implementations of the subject matter described herein are set forth in detail in the following figures and specification. Other features, aspects, and advantages of this subject matter will become apparent from the specification, figures, and claims. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of an exemplary setup for heating a bulk medium.

[0011] Figures 2A-2B This is a schematic diagram illustrating an exemplary setup for heating a bulk medium, which utilizes the skin effect to concentrate the current density in a first direction within the bulk conductor.

[0012] Figure 3 It is a plot showing the concentrated increase in current density as a function of applied AC current due to the skin effect.

[0013] Figures 4A-4D This is a schematic diagram illustrating an exemplary setup for heating a bulk medium, which utilizes the proximity effect to concentrate the current density in a second direction within the bulk conductor.

[0014] Figures 5A-5B This is a concentrated simulation graph showing the increase in current density in a block conductor near a second conductor as a function of the distance between conductors due to the proximity effect.

[0015] Figure 6A This is a schematic diagram of an exemplary setup for heating a bulk medium using an electrode array.

[0016] Figures 6B-6D This is a schematic diagram of an exemplary setup for heating a bulk medium using various electrode arrangements.

[0017] Figure 7 This is a schematic diagram of an exemplary signal conversion unit (“STU”) including a main subunit for converting to normalized power (“TSP”) and a main subunit for generating AC (“ACG”).

[0018] Figure 8 This is a schematic diagram of an exemplary STU including a TSP main subunit, an ACG main subunit, and a control main subunit.

[0019] Figure 9A This is a schematic diagram of an exemplary TSP sub-unit including a flyback converter and a common choke.

[0020] Figure 9B This is a schematic diagram of an exemplary flyback converter.

[0021] Figure 10A This is a schematic diagram of an exemplary ACG subunit including a Class D amplifier with dual MOSFET transistors, a temperature-controlled quartz oscillator (“TCXO”), and a gate driver.

[0022] Figure 10B This is a schematic diagram of an exemplary Class D switched amplifier.

[0023] Figure 10C This is a schematic diagram of an exemplary ACG sub-unit including a Class D amplifier with dual MOSFET transistors, a TCXO, a gate driver, and a low-power conversion stage (“LPC”).

[0024] Figure 11 This is a schematic diagram of an exemplary control subunit that includes a microcontroller and an LPC.

[0025] Figure 12 This is a diagram of the impedance regulation network between the source and the load.

[0026] Figure 14 This is a schematic diagram of an exemplary regulation network unit including a passive regulation subunit.

[0027] Figure 15A This is a schematic diagram of an exemplary regulation network unit that includes an active regulation subunit and a control subunit.

[0028] Figure 15B This is a schematic diagram of an exemplary regulation network unit including an active regulation subunit, an LPC, and a control subunit.

[0029] Figure 16 This is a schematic diagram of the cable level in an exemplary heating system.

[0030] Figure 17 This is a schematic diagram of an exemplary electrode used in a heating system.

[0031] Figure 18A This is a schematic diagram of an exemplary brazed joint attachment between an electrode and a bulk dielectric.

[0032] Figure 18B This is a schematic diagram of an exemplary rivet fastener attachment between an electrode and a bulk medium.

[0033] Figure 18C This is a schematic diagram of an exemplary air-sealed tape attachment between the electrode and the bulk medium.

[0034] Figure 18D This is a schematic diagram of an exemplary combination attachment between an electrode and a bulk dielectric.

[0035] Figure 19 This is a cross-sectional view of an exemplary coupling strip for providing a high-frequency heating signal to a bulk medium, as implemented according to the present invention.

[0036] Figure 20 Depicting the wings of the aircraft Figure 19 An exemplary layout of the coupling strips.

[0037] Figure 21 A top view of several exemplary coupling strips is depicted to illustrate various configurations of the conductive layer within the coupling strips.

[0038] Figure 22A A plot of simulated current density generated by an exemplary coupling strip in the aircraft skin and an electric field density between the coupling strip and the aircraft skin is depicted.

[0039] Figure 22B Depicting in Figure 22A A plot of simulated current density generated in the skin of the aircraft.

[0040] Figure 23 A layout diagram depicting several exemplary conductive layer arrangements within a coupling strip is provided.

[0041] Figure 24A Depicting according to Figure 23 The cross-sectional view of the coupling strip taken at A-A' of layout A.

[0042] Figure 24B Depicting according to Figure 23 The cross-sectional view of the coupling strip taken at B-B' of layout B.

[0043] Figure 24C Depicting according to Figure 23 The cross-sectional view of the coupling strips taken at C-C' of layouts C and D.

[0044] Figure 25A A cross-sectional view depicts an exemplary configuration for attaching a coupling strip to a bulk medium.

[0045] Figure 25B A cross-sectional view is depicted of another exemplary configuration for attaching coupling strips to a bulk medium.

[0046] Figure 26A It is a cross-sectional view of the coupling strip with double-sided adhesive underlayer before it is installed on the bulk medium; Figure 26B It is installed on the block medium Figure 26A A cross-sectional view of the coupling strip.

[0047] Figures 27A-27F Cross-sectional views of various implementations of embedded coupling strips are depicted.

[0048] Figure 28 A diagram depicting the implementation of the coupling strip connector is provided.

[0049] Figure 29 A diagram depicts another implementation of the coupling strip connector.

[0050] Figure 30 This is a block diagram of a first exemplary bulk medium heating system utilizing coupling strips according to the present invention.

[0051] Figure 31 This is a block diagram of a second exemplary bulk medium heating system utilizing coupling strips according to the present invention.

[0052] Figure 32 This is a block diagram of a third exemplary bulk medium heating system utilizing coupling strips, implemented according to the present invention.

[0053] The same reference numerals and symbols in the various figures indicate the same elements.

[0054] Figure 33 This is a partial diagram depicting the pilot's field of vision on an aircraft with temperature coverage of its wings.

[0055] Figure 34 This is a diagram depicting the Time Domain Reflectometry (TDR) technique.

[0056] Figure 35A This is a plot showing a comparison between two transmission lines measured using a TDR, one line including a connector at 2 meters.

[0057] Figure 35BThis is a plot showing a frequency domain analysis that illustrates the impedance change following a dent caused by an impact.

[0058] Figure 36 It is a plot depicting a comparison of two transmission lines measured using a TDR, with one line having an indentation in its test panel.

[0059] Figure 37A , Figure 37B and Figure 37C An example cockpit announcement display is depicted.

[0060] Figure 38 A schematic diagram depicts an exemplary implementation of a coupling strip configured with fault sensing lines.

[0061] Figure 39A A schematic diagram depicts another exemplary implementation of transmission of a coupled strip configured with a fault sensing line.

[0062] Figure 39B A schematic diagram depicts yet another exemplary implementation of transmission of a coupled strip configured with a fault sensing line.

[0063] Figure 40 A plot of impedance and temperature as a function of time on the coupling strip during the de-icing operation is depicted.

[0064] Figure 41 This is a 3D plot of the dielectric constant of an example acrylic adhesive material over the operating temperature range.

[0065] Figure 42 This is a plot of the dielectric constant of an example acrylic adhesive material over the operating temperature range.

[0066] Figure 43 A plot of the frequency response of the non-faulty line and the faulty line is shown. Detailed Implementation

[0067] The heating system described in this specification uses AC current to increase the effective resistance of the conductive material (e.g., aluminum, carbon fiber composites) to make it easier to heat. Generally, the heat generated in the conductive material can be used to melt ice forming on the surface of the conductive material. Heat can also be used to maintain the conductive material at an elevated temperature to prevent vapor deposition on the surface or to prevent water from freezing on the surface and to prevent the accumulation of freezing precipitation (e.g., snow, ice balls, fog, freezing rain) on the surface. For example, the heat generated in the conductive material can be conducted (e.g., diffused) throughout the conductive material. Additionally, the generated heat can induce convection at the interface between the conductive material and any liquid on the surface, in order to, for example, heat the liquid and prevent it from freezing.

[0068] Many electromagnetic effects can be induced using alternating current to increase the effective resistance of conductive materials, thereby promoting Joule heating within the conductive material. These effects include the skin effect, proximity effect, induction, eddy currents, hysteresis loss, and dielectric loss. Utilizing the skin effect, if the frequency of the current in the conductor is set to a sufficiently high value, most of the current will pass through the skin depth of the conductive material, which is significantly smaller than the geometric thickness of the conductive material. Additionally, specific device geometries can be used to induce a proximity effect within the conductive material, which further constrains the width of the current density, thereby further increasing the effective resistance along the current path within the conductive material. In summary, both of these effects can be used to increase the resistance of conductive materials and lead to Joule heating.

[0069] For example, Joule heating generally refers to the heat generated by passing an electric current through a conductor. The heat generated in a given current-carrying conductor is proportional to the material's resistance multiplied by the square root mean square of the current amplitude:

[0070] .

[0071] Generally, the heat output from a heating element is increased by increasing the current through the conductor and by using a heating element with relatively high resistance. However, the present invention achieves Joule heating by utilizing specific electromagnetic phenomena (e.g., skin effect and proximity effect) to cause a contraction in the current density of the local current within the bulk medium. This contraction in current density produces an increased effective resistance along the current path within the bulk medium. Although the specific effects can vary in geometries in different materials, the effective resistance along a given length of the current path through the bulk medium can generally be expressed as:

[0072] ,

[0073] Where ρ represents the resistivity of the material through which the current flows, l represents the length of the current path, and A eff The contracted cross-sectional area represents the current density. This invention utilizes electromagnetic phenomena to... eff The area is reduced to a size smaller than the cross-section of the bulk dielectric along the current path, thereby increasing the effective resistance of the bulk dielectric to a level higher than the resistance of the bulk dielectric to DC current.

[0074] Some implementations of the present invention can use these electromagnetic phenomena to increase the length of the current path through the bulk medium. For example, as referenced below... Figure 4DThe techniques described herein can be used to "redirect" current paths along indirect routes (e.g., serpentine paths) between two electrodes attached to a bulk medium. Indirect routes can create current paths that, for example, have an effective length (l) longer than a generally straight path that would be produced by passing current between two electrodes without electromagnetic effects such as proximity effects. eff Therefore, the system described herein can increase the current path length l to an effective length (l) longer than the direct path the current would take without the various systems and conductor arrangements described herein. eff Therefore, this can be achieved by increasing the effective cross-sectional area (A) of the current flowing through the bulk medium. eff ) shrinks and also increases the effective length of current passing through the bulk medium (l) eff To increase the effective resistance (R) eff This further increases the effective resistance of the bulk dielectric to a level higher than the resistance of the bulk dielectric to DC current. In such an implementation, the effective resistance can generally be expressed as:

[0075] .

[0076] By using this technique, the present invention can generate high local resistance in conductive bulk materials (e.g., aluminum, copper, steel and their alloys).

[0077] As used herein, the skin effect generally refers to the tendency of alternating current to be unevenly distributed in a conductor, resulting in a higher current density near the conductor surface that decreases with increasing distance from the surface. The strength of the skin effect increases with the frequency of the current and the conductivity of the material carrying the current. Some implementations of the present invention can modulate the skin effect so that the current flows more at a higher AC frequency at the outer surface of the conductor (e.g., the "skin depth").

[0078] Generally, the skin effect in a conductor can be expressed by the following formula:

[0079]

[0080] Where J is the current density, J s Here, ρ is the surface current density, d is the depth of the point where the current density is calculated, δ is the skin depth, ρ is the resistivity of the conductor, ω is the angular frequency of the current, μ is the permeability of the conductor, and ε is the dielectric constant of the conductor. In the case of a cylindrical conductor with a base radius R, the current density can be further derived as:

[0081]

[0082] Where J0 is a Bessel function of the first kind, order 0.

[0083] In the case of a rectangular, infinitely long and wide plate with surface current flowing, the skin effect can be expressed by the following equation:

[0084]

[0085] Among them, J s Here, σ is the forced surface current, σ is the plate conductivity, e is the plate thickness, and sh is a hyperbolic sine function. For example, in... Figure 3 The diagram shown below, and discussed in more detail, illustrates an example of current density contraction within the material depth (e.g., skin depth) of a cylindrical conductor due to the skin effect. As mentioned above, this contraction of the effective cross-section increases the effective resistance of the conductor.

[0086] For example, in Figure 3 The diagram shown below, and discussed in more detail, illustrates an example of current density contraction within the material depth (e.g., skin depth) caused by the skin effect.

[0087] As used here, the proximity effect generally refers to the influence of the AC current flowing in a first current path (e.g., a conductor) on the current density of the AC current flowing in a nearby second current path. For example, as in Figures 5A-5B As shown and described in more detail below, the AC current in the first current path causes the density of the AC current in the second current path to "cluster" or contract around the first current path. In an implementation of the invention, for example, when conductors are placed adjacent to current flowing through a bulk medium, the density of the current flowing through the bulk medium is "pulled" toward another conductor carrying the AC current. The extent and direction of the current density contraction (e.g., clustering) caused by the proximity effect depend on several variables, including, for example, the distance between the two or more AC current paths, the direction of current travel relative to each other in the respective current paths, the frequency of the AC current in the current paths, and the amplitude of the respective currents in the current paths.

[0088] For clarity, the heating system of the present invention will be described with reference to an example scenario of de-icing and anti-icing systems used on the outer surfaces of aircraft. However, the heating system of the present invention can be used in other scenarios, including but not limited to heating the surfaces of other aircraft, drones, wind turbines, cryogenic operating units, heat pumps, automobiles, radio towers, railway tracks, manned or unmanned military vehicles, roofs, or other conductive surfaces that can benefit from control of ice or water formation. The heating system can be used for de-icing or anti-icing. In some implementations, the heating system can be used to heat a less conductive material by, for example, applying a conductive layer over or inside a non-conductive material. This implementation can be used to heat surfaces of roads (e.g., driveways), building materials, roofs, floors, or other low-conductivity or non-conductive materials.

[0089] As used herein, de-icing generally refers to the removal of snow, ice, or frost (collectively referred to as "ice") from a surface. In some implementations, the heating system can only melt a portion of the existing ice on a conductive surface. The ice is then removed from the surface (e.g., by sliding off the surface once the melting process begins and the ice-surface bond breaks).

[0090] As used herein, anti-icing generally refers to the prevention of the formation or adhesion of snow, ice, or frost (collectively referred to as "ice") on a surface. In some implementations, heating systems maintain the surface temperature sufficiently high to prevent ice from forming on the surface and to prevent ice buildup or formation (e.g., to prevent freezing precipitation such as snow, frost, ice balls, freezing rain, etc.).

[0091] Figure 1 A block diagram of an example heating system 100 for heating a bulk medium is shown. The heating system 100 includes a power control system 104 coupled to electrodes 116 and 118. Electrodes 116 and 118 are coupled to a target area of ​​the bulk medium 102 (e.g., a portion of an aircraft wing). The power control system 104 generates alternating current (AC current) (e.g., at a frequency of 1 kHz or higher) across a closed circuit via wire (or path or cable) 106, the bulk medium 102, and a final wire (or return path) 108. The direction of the current 112 through the wire is indicated by a dashed arrow.

[0092] In some implementations, the heating system 100 may include, but is not limited to, a power control system 104, electrodes 116 and 118, and dedicated cables (e.g., wires 108 and 106). In some implementations, the heating system is configured to be coupled to electrodes 116 and 118. In some implementations, the heating system is configured to be coupled to dedicated cables (e.g., 108 or 116). In some implementations, the power control system 104 may include, but is not limited to, a signal generation unit, a power supply, a signal conversion unit, an impedance adjustment network, a control unit, and sensors, the specific configuration of which is described in more detail below. As detailed below, in some implementations, the impedance adjustment network is an impedance matching network.

[0093] In some implementations, electrodes 116 and 118 are contact electrodes. For example, electrodes 116 and 118 are physically connected to bulk medium 102 to conduct current from power control system 104 to bulk medium. In some implementations, electrodes 116 and 118 may be coupled to bulk medium 102 but electrically insulated from it. For example, in such an implementation, electrodes 116 and 118 may be the input and output of an induction coil positioned adjacent to bulk medium 102 to magnetically induce current in bulk medium 102.

[0094] The power control system 104 can supply current at a sufficiently high frequency (e.g., above 1 kHz) to cause the current flow between electrodes 116 and 118 to contract in the z-direction by adjusting the skin effect, resulting in a higher resistance of the bulk dielectric 102. For example, the power control system 104 can provide AC current at frequencies between 1 kHz and 300 GHz. In some implementations, the current frequency is between 10 kHz and 30 GHz. In some implementations, the current frequency is between 100 kHz and 450 MHz. In some implementations, the current frequency is in the range of 1 MHz to 50 MHz, 100 MHz to 150 MHz, 200 MHz to 300 MHz, 400 MHz to 500 MHz, or 800 MHz to 1 GHz.

[0095] In some implementations, return path 108 is arranged close to the surface of bulk medium 102. The proximity of return path 108 relative to the surface of bulk medium can be used to adjust the proximity effect of the current flowing between electrodes 116 and 118, thereby further constricting the current and increasing heating within the bulk medium. To utilize the proximity effect to shape the current flowing between electrodes 116 and 118, a return current path 108 from the heating system circuitry itself is not required. In some implementations, another current path 122 (e.g., from a different circuit) can be placed very close to bulk medium 102 (e.g., at a distance of 120a). For example, when the distance between current path 108 or 122 and bulk medium 102 is sufficiently small (120a or 122a), the proximity effect can be used to further confine the current flowing through the bulk medium.

[0096] For example, the distance 120 (or 120a) between the bulk medium and path 108 (or 122) can be less than 1 m, or less than 50 cm, or less than 10 cm to produce a proximity effect. If a closer distance is possible when considering design constraints (e.g., using an aircraft wing as the bulk medium, where the wing ribs or spars of the aircraft are not on the return path 108 / 122), then the distance 120 (or 120a) can be less than 25 cm or less than 10 cm.

[0097] The bulk medium 102 may include materials such as, but not limited to, aluminum, metal alloys, carbon fiber composites, copper, silver, titanium, or steel. For example, the bulk medium may be any part of the aircraft frame (e.g., the outermost shell or surface of an aircraft, also known as the aircraft's "skin"), such as the fuselage, wings, landing gear, tail, etc.

[0098] The electrodes (116 and 118) may include materials such as, but not limited to, aluminum, silver, copper, their alloys, or other conductive materials. In some implementations, the electrode material is at least as conductive as the bulk medium 102. In some implementations, electrodes 116 and 118 may be arranged as an array of electrodes. The electrodes may be coupled to the bulk medium in a variety of ways, such as being coupled to the top or bottom surface of the medium or embedded within the medium.

[0099] The heating system 100 is configured to generate an effective resistance through the bulk medium 102 by shaping the density of the current passing through it. In other words, for aircraft applications, the existing frame of the aircraft will be used as part of the heating system's circuitry. The heating system 100 shapes the current density by adjusting the skin effect, proximity effect, or a combination thereof to increase the effective resistance of the bulk medium 102 along the current path between electrodes 116 and 118. In some cases, the proximity effect is also utilized to guide the current path, for example, as... Figure 4D As seen, the desired portion of the bulk medium is heated. The desired heating portion of the bulk medium may be referred to as the "target heating location" or "target location".

[0100] In some implementations, an alternating current with a frequency of 1 kHz or higher can be passed directly through the aircraft frame. As a result, Joule heating will occur in the portion of the frame surface where the current flows. Additionally, the heat generated by the current will diffuse through conduction throughout the bulk medium 102.

[0101] refer to Figures 2A-2B The heating system 100 shapes the current density passing through the target region 102 of the medium by utilizing the skin effect. For example... Figure 1 In the process, an AC current (along direction 212) is applied across electrodes 116 and 118 through the target region of the bulk medium 102. Figure 2A This is a schematic diagram (e.g., a side view) showing the distribution of current density 202 through a target region of bulk medium 102 in the absence of skin effect (e.g., current frequency below 1 kHz). The current travels in the y-direction (212), with most of the current flowing within the volume of medium 102 indicated by the arrow. For example, the current has a depth 206 of approximately 2 mm, which is almost the entire thickness of the bulk medium. Therefore, Figure 2A The operation of system 100 is shown, in which current density is shaped with little or no skin effect.

[0102] Figure 2B This is a schematic diagram of the distribution of current density 202 resulting from the application of a high-frequency AC current (e.g., exceeding 1 kHz) across the electrodes. Figure 2BThe operation of a system 100 that shapes current density through the skin effect is illustrated. For example, due to the skin effect generated by heating the system 100 at high frequency, the depth of the current density 202 flowing through the bulk medium 102 contracts in the z-direction to a narrow region near the surface of the bulk medium 102. Furthermore, the effective resistance of the bulk medium 102 in the current flow region is sufficiently increased to allow Joule heating to be achieved in this region without overheating the rest of the circuit (e.g., wires, power supply, inverter, regulation network, electrodes). The effective resistance of the bulk medium to the AC current in the target region can be greater than the resistance of the bulk medium to the DC current. For example, the effective resistance can be two or more orders of magnitude higher than the resistance of the bulk medium to the DC current.

[0103] Figure 3 This is a plot showing the concentration of current density (y-axis, normalized to 1) as a function of applied AC current towards the material depth (x-axis, normalized to 1) due to the skin effect. The current density decreases exponentially along the dielectric thickness (z-direction). As the frequency increases from 1 kHz to 10 MHz, the current density becomes more concentrated near the surface of the bulk dielectric. Therefore, the higher the frequency, the more pronounced the attenuation. In other words, the skin effect causes the current density to contract, resulting in current passing through a thin layer near the surface of the bulk dielectric. Joule heating will therefore also occur in this layer.

[0104] Figure 4A This is a side view schematic diagram of a system 400 used to further constrain current density by utilizing the proximity effect. (See diagram below.) Figure 1 In this configuration, electrodes 116 and 118 are attached to bulk medium 102 (e.g., a target area on the fuselage) and allow an AC signal (e.g., exceeding 1 kHz) to pass through, creating a current density (or path) 410 having a direction 412 through the medium. A return path 108 is located within a distance 120 from the current path (or density) 410 in the medium and has a direction 112 different from the direction 412. In some implementations, the return path 108 is electrically insulated from the bulk medium 102. For example, the return path 108 may be a wire or cable located within a distance 120 from the bulk medium 102. The return path 108 may also be a wire or cable completing the circuitry of system 400.

[0105] If the return path 108 is sufficiently close to the current path 410 (e.g., less than 50 cm), the AC current in the return path 108 constrains the current in the current path 410 in the direction of the current flow path across the current path 410. In other words, positioning the return path 108 sufficiently close to the current path 410 causes a contraction in the cross-sectional area of ​​the current flow in the current path 410. For example, refer to... Figures 4A-4CThe current contracts between electrodes 116 and 118 in two directions (e.g., the x and z directions as shown in the figure). For example, as... Figure 4D As shown, the proximity effect causes the current density 410 to contract along the x-direction or y-direction depending on the direction of current flow. For example, when the current flows along the x-direction, the proximity effect causes the current to contract along the y-direction. For example, the proximity effect primarily causes the current to contract across the direction of current flow, while the skin effect primarily causes the current density to contract within the depth of the bulk medium (e.g., along the x-direction). Figure 2A and 2B The current density contractes in the depth (e.g., in the z-direction) of the bulk medium 102. In some cases, the proximity effect can also increase the contraction of the current density in the depth (e.g., in the z-direction) of the bulk medium 102, for example, by enhancing the skin effect in implementations that utilize both the skin effect and the proximity effect. In some implementations, the proximity effect can also be used to define the direction of current flow through the bulk medium (e.g., the path followed by the current through the bulk medium 102).

[0106] Figures 4B-4C This is an exemplary schematic diagram of system 400 as seen from top. Electrodes 116 and 118 are attached to a bulk medium target region 102 and allow an AC signal (e.g., exceeding 1 kHz) to pass through to create a current density (or current path) 410 with a direction 412 through the medium. A return path 108 lies in a different xy plane (dashed line) than the current path (or density) 410 in the bulk medium 102. In some implementations, the current flow in the return path 108 lies in a direction 112 different from the current flow direction 412 in the current path 410 through the bulk medium 102. For example, in some implementations, the direction 112 of the current flow in the return path 108 is opposite to the direction 412 of the current flow in the current path 410. When the distance 120 from the return path 108 to the current path 412 is sufficiently small (e.g., less than 50 cm), such as Figure 4C As shown, due to the proximity effect, the current flowing between electrodes 116 and 118 within the bulk medium 102 will concentrate near the return path wire (e.g., contracting in the y and z directions). Figure 4B As shown, the greater the distance of the return path 108 from the bulk medium 102, the less constrained the current path 412 in the bulk medium 102 is.

[0107] Figure 4DThis is an exemplary schematic diagram of another implementation of system 450, viewed from above. As in the previous system 100, electrodes 116 and 118 are attached to target regions of bulk medium 102. Return path 108 is positioned adjacent to bulk medium 102 and in a different xy plane than the current path 410 within bulk medium 102. The implementation shown illustrates how return path 108 (or another separate current path) can be used to shape the path followed by current 410 through bulk medium 102. For example, by placing a second current path (e.g., a current-carrying wire or cable, such as return path 108, etc.) adjacent to bulk medium 102, the proximity effect can be utilized to constrain the width of the current density across the current flow direction and also shape the current path 410 within bulk medium 102. Figure 4D It also demonstrates that the proximity effect constrains the current density along the current path 410 across the current flow direction. For example, in Figure 4D In this process, the current density along the current path 410 is constrained in a direction substantially perpendicular to the current flow direction in each segment of the path 410, and the current path 410 within the bulk medium 102 conforms to the shape of the return path 108. More specifically, in section A of the current path 410, the current is directed to flow along the x-direction, and the current density contracts in the y- and z-directions. In section B of the current path 410, the current is directed to flow along the y-direction, and the current density contracts in the x- and z-directions.

[0108] like Figure 4D As shown, the ability to shape current paths into more complex geometries using the proximity effect can offer several advantages. First, such path geometry can be used to increase the effective current path length *l*. As mentioned above, the increased path length leads to increased resistance, and thus increased Joule heating. Second, the current path geometry can be configured to direct current flow to strategic locations for heating. Third, the current path geometry can be used to create increased heating areas (e.g., hot spots) at the sharp corners of the current path.

[0109] Due to the combination of proximity and skin effects, the effective resistance of a bulk dielectric to AC current in a target region can be greater than the resistance of the bulk dielectric to DC current. For example, the effective resistance can be two or more orders of magnitude higher than the resistance of the bulk dielectric to DC current.

[0110] Figures 5A-5B This is a concentrated simulation graph illustrating the increase in current density in the bulk conductor target region 102 near the second conductor / path 108 as a function of the distance 120 between the conductors due to the proximity effect. When the distance 120 decreases, the current in the bulk conductor and the second path becomes sufficient to cause the proximity effect (e.g., exceeding 1 kHz or 10 MHz). For example, as... Figure 5A As shown, when the distance 120 is 20 cm, the current density 410 remains approximately uniform in the xy plane. When the distance 120 decreases to 2 cm, as... Figure 5B In this way, the proximity effect causes the current 410 to "converge" or "contract" around the return path 108 in the xz plane. This is achieved by concentrating most of the current 410 along a narrow strip of the bulk conductor and following the path (108) of the second conductor (e.g., the return path or other current-carrying wire). In other words, the current 410 follows a path of minimum inductance rather than spreading uniformly throughout the bulk medium.

[0111] In some implementations, wires other than return path 108 are used to induce a proximity effect, such as Figure 1 Path 122 is shown in the diagram. In this case, the current oscillation in the wire may or may not be driven by the same system as paths 106 and 108 (e.g., power control system 104). In this case, the proximity effect of wire 122 will depend on the distance between wire 112 and the current path 412 in the bulk conductor. Just as with the return path 108, wire 122 may need to be close enough to path 412 (e.g., less than 50 cm).

[0112] Generally, the power control system 104 delivers current to the bulk medium 102 via electrodes (e.g., 116 and 118) and custom electrical conductors (e.g., dedicated wires or dedicated cables) to form a closed circuit (see [link]). Figure 1 The following will explain these three components in further detail.

[0113] In some implementations, such as Figure 6A As shown, electrodes 116 and 118 comprise arrays of input electrodes and output electrodes. Electrode system 600 includes three input electrodes 116(1)~(3) forming electrode array 116 and three output electrodes 118(1)~(3) forming electrode array 118 and resulting in adjacent current paths 410 in the bulk medium. As detailed above, the proximity effect caused by the current 112 in the return wire 108 constrains the current density 410 in the bulk medium.

[0114] Generally, various electrode geometries can be used to achieve the desired heating in the target area of ​​the bulk medium 102. For example, refer to Figure 6B System 610 illustrates two electrode arrangements 116 and 118 (with input / output wires 106 and 108) for applying current through a target region 102 of the bulk medium. Electrode arrangements 116 and 118 can be as follows: Figure 6A An array of one or more electrodes is shown. Figures 6C-6DThese are schematic diagrams of other electrode configurations 620 and 630 used for heating, for example, a target area 120 on an aircraft wing. Figure 6A As shown, the electrode arrangements indicated by 116, 118, and 640 can be a single electrode or an array of one or more electrodes. The electrode shapes and designs are further detailed below.

[0115] In some implementations, the bulk medium is the aircraft skin, and the target areas for heating include, but are not limited to, the following: wings, fuselage, vertical stabilizer, horizontal stabilizer, windows, winglets, windshield, control surfaces (flaps, ailerons, rudders, elevators, air brakes, etc.), nose / nose cone, landing gear, landing gear brakes, landing gear doors, engines and engine nacelles, AC inlets and outlets, fuel tank vents, pitot tube heads, static pressure ports, and other antennas, sensors, and external lights, fuel tank vents, and maintenance panels. In other words, the proposed technology may involve placing electrodes inside the frame (in some cases, placed...) Figures 6A-6D (In one or more configurations shown). In some implementations, the heating system 100 will generate Joule heating in a portion of the target region, and subsequently, conduction within the material can lead to more “diffuse” heating.

[0116] Generally, the power control system 104 includes a signal generation system designed to generate a high-frequency (e.g., above 1 kHz) alternating current (AC) signal and transmit it through the aforementioned target region 102 via the bulk medium. In some implementations where the impedance of the target region is low (in some cases well below 1 Ω), the signal generation system is configured to generate and maintain a desired current level to produce Joule heating at the target region. In some cases, high currents through other parts of the system (e.g., electrical conductors or wires transmitting the signal) will produce undesirable Joule heating outside the target region because the impedance of other parts of the system (e.g., electrical conductors or wires transmitting the signal) is above zero. For this reason, in some implementations, the signal generation system is designed such that only high currents are delivered to locations close to the target region.

[0117] In some implementations, some or all of the components / units of the signal generation system, as well as the conductive units / cables connecting them, are designed to minimize as much of the undesirable power loss that typically occurs when transmitting high-current and high-frequency electromagnetic signals.

[0118] In some implementations, the signal generation system can receive power from an existing power source (e.g., an existing electrical bus on the aircraft). In other implementations, the system uses a custom battery or custom power source that is part of the system. Such a custom power source may include, but is not limited to, fuel-based generators, solar-based generators, wind-based generators, gas-powered generators, etc. In some implementations, the signal generation system may be placed in the circuitry between the power source (e.g., an existing electrical bus, a custom battery, a custom power source) and the target area.

[0119] Additionally, in some implementations, the signal generation system may include control circuitry and devices that exist as independent units and / or are embedded in a combination of other units that are part of the signal generation system.

[0120] In some implementations, heating system 100 is used to heat many different target areas. In this case, the components or units of the heating system (e.g., signal conversion units, impedance conditioning networks, etc.) can be centralized for the entire system or distributed as different units or more for each target area or group of target areas. Centralized or distributed configurations can be used to improve system functionality, energy efficiency, cost, regulatory compliance, weight, size and complexity, and other criteria. For example, in some implementations, the signal conversion unit is centralized, while the impedance conditioning network is distributed to one or more units for each target area. In some implementations, the signal conversion unit is only partially centralized using a centralized TSP ("Convert to Normalized Power") subunit, but is distributed to one or more subunits for each target area or group of target areas using an ACG ("AC Generation") subunit. In some implementations, the signal conversion unit is fully distributed, with each subunit distributed to one or more subunits for each target area or group of target areas.

[0121] In some implementations, the power control system 104 continuously supplies power to the target area 102 until the heating / de-icing / anti-icing operation is complete. In some implementations, the system can be switched on and off in an improved / efficient manner (e.g., using a control unit) to achieve desired heat generation and distribution in the conductive material 102. For example, during system on-time, heat is generated at specific locations within the target area and conducted across the target area, thus "spreading" to the rest of the target area. During system off-time, the generated heat continues to be conducted within the target area.

[0122] In some implementations, the system may include different power levels for the on state and cycle through the off state and different power levels in an improved manner. In some implementations, instead of a one-step power increment or decrement, a specific power level can be achieved through a smooth increase / decrease in power. This pulsed power system pattern can be fully predefined when the system is built, or it can vary and be dynamically improved based on the feedback loop of the control unit that forms the system, as detailed below.

[0123] In some implementations of heating systems that include several target areas, the aforementioned pulsed power pattern can be used asynchronously across all target areas, ensuring that all target areas are heated within the desired timeframe while maintaining the total average power level and total instantaneous power level below a set threshold. For example, in an aircraft de-icing system where both wings, fuselage, and horizontal and vertical stabilizers are to be heated, this phased power pattern can be designed to power on only one target area at a time. In some implementations, the phased power pattern could be: powering on the left wing, then the fuselage, then the right wing, then the vertical stabilizer, and then the horizontal stabilizer.

[0124] In some implementations, improved timing can be used at each level to achieve desired heat, average power, instantaneous power levels, and acceptable heat distribution. In other implementations, similar to the above model, any subset of the target region can be heated at a given time.

[0125] In some implementations, one or more units or elements mentioned as part of the heating system design will have an enclosure. This enclosure can be designed for a single unit or any combination of units. In some implementations, the enclosure is designed to meet environmental qualification standards. For example, the enclosure may be designed to meet standards such as non-flammability, protection against precipitation, attachments and construction providing protection against external shock and vibration, electrical insulation, protection against external electromagnetic interference (“EMI”) and shielding of EMI emissions from enclosed circuitry, and thermal mitigation.

[0126] In some implementations, the housing may be designed to function as a heat sink, for example, by using a structure of the object being heated (e.g., a bulk conductive material). For instance, one or more units of the heating system may be housed within a metallic or conductive structure mounted to have high thermal conductivity to the bulk medium it resides in. One potential benefit of this mounting is that it both heats the bulk medium and provides necessary cooling for the electronic equipment. Another potential advantage of this design is that it reduces the weight of the heating system (or device) by eliminating the need for a separate heat sink to dissipate losses. In some implementations, the target area may be used as part of the heat sink for the heating system unit. This use can improve the efficiency of the heating system because the circuitry of the heating system inevitably generates heat losses that can be conducted to the target area to heat it.

[0127] In some implementations, a variety of adhesives or mounting types can be used to mount the housing onto the bulk medium. For example, an adhesive primarily used to maintain mechanical rigidity can be used to hold the housing in place, while different adhesives (or interfaces) can be used to provide a lower thermal resistance path for the housing's heat dissipation function.

[0128] In some implementations, one or more units of the heating system may be configured to detect one or more measurements, including but not limited to voltage, current, temperature, forward power, and reflected power measured on the unit's circuitry, surrounding cables, other units, or the target area. In some implementations, such measurements can then be used to monitor the unit's operating status and (using feedback mechanisms) control its operation, including on / off switching, output level, and in-circuit control of switches and tunable sections for improvement (more details regarding the control of switches and tunable sections within the dynamic regulation network can be found below). Controlled parameters may include load power and / or load current, voltage control in the regulation network, and other relevant signals.

[0129] In some implementations, the measurements used as part of the aforementioned feedback loop may also include specific ice sensors that can be mounted on or near the target area. Such sensors can be used, for example, to notify the heating system and / or the user of the de-icing completion status and to act as inputs to adjust power levels during de-icing and anti-icing operations. In some implementations, the ice sensors may also be used to determine faults and / or service requirements within the system.

[0130] In some implementations, the heating system may include a protocol converter control unit (or “control unit” or “control subunit”) that receives input from the user (in the case of an aircraft de-icing system, this could be the pilot or co-pilot) and / or the system’s sensors and outputs control signals to all other units. In some implementations, user input may include, but is not limited to, on / off status, de-icing / anti-icing / off status, target temperature of the target area, and target power output of the target area. In some implementations, sensor input may include, but is not limited to, voltage, current, temperature, forward and reflected power, impedance, and data from ice sensors, plate switches, various aircraft logic units, information from avionics, and other data. In some implementations, the protocol converter unit is centralized for the entire system. In some implementations, the protocol converter unit is distributed, with one protocol converter control unit for each target area or group of target areas.

[0131] In some implementations, user input can be transmitted to the control unit via wires (e.g., using data transmission standards such as ARINC 429) or wirelessly (e.g., using Bluetooth Low Energy or Wi-Fi connectivity). In some implementations, the user input device can be integrated into a system being heated (e.g., integrated into the cockpit screen controls of an aircraft de-icing system), or it can be a separate device, such as a touchscreen tablet (e.g., a separate tablet mounted in the cockpit, or a special application mounted on the pilot's touchscreen tablet in the case of an aircraft de-icing system).

[0132] In some implementations, the power control system 104 includes a signal conversion unit (“STU”) or circuitry that transforms a signal from an existing electrical bus or any other power source from a custom battery or heating system into a desired high-frequency AC waveform to generate current in the bulk medium. For example, in aircraft applications, the signal conversion unit may take DC power available from the aircraft's electrical bus and convert it into a desired high-frequency AC signal. In another aircraft example, the signal conversion unit may take power available from the aircraft's electrical bus in the form of an AC signal and convert it into a desired high-frequency AC signal. In some implementations, the signal conversion unit may take DC power available from a custom battery or from any custom power source (e.g., forming part of a heating system) and convert it into a desired high-frequency AC signal. In some implementations, the custom battery or power source may be embedded within the same housing and / or circuit board as the signal conversion unit.

[0133] Figure 7 This is a schematic diagram of an exemplary signal conversion unit (“STU”) 700 used in the power control system 104. The STU 700 includes a main sub-unit for converting to normalized power (“TSP”) 710 and a main sub-unit for AC generation (“ACG”) 720, which are located before other circuitry 730 in the remainder of the device 100. Figure 7 As shown, the power control system 104 can draw power from an existing power source.

[0134] Figure 8 This is a schematic diagram of an exemplary signal conversion unit (“STU”) 800 used in the power control system 104, which includes a TSP 810, an ACG 820, and a control subunit 830.

[0135] In some implementations, the TSP draws power from the battery of an existing power supply or heating system and converts it into a standardized input, such as 250 VDC for improved operation of ACG and for improved power transfer efficiency of the signal conversion unit.

[0136] In some implementations where the existing electrical bus supplies power to the TSP in the form of a 400Hz, 115VAC signal, the TSP may include a flyback converter with a filter (such as a common choke) at the output to prevent electromagnetic interference from reaching or damaging the ACG. Figure 9A This is a schematic diagram of an exemplary TSP subunit 900 including a flyback converter 910 and a common choke 920. Figure 9B This is a schematic diagram of an exemplary flyback converter 910.

[0137] In some implementations, the TSP is a bridge rectifier that converts AC power from an existing power source to any desired DC voltage. In other implementations, the TSP draws DC power from a battery or existing power source (e.g., typical 28VDC in an aircraft) and transforms it to a different DC or AC voltage. For example, DC-DC conversion can be used in power control units and components of a heating system, where possible voltage levels could include ±3.3V, ±5V, and / or ±12V. Finally, in some implementations, a power factor correction (“PFC”) stage can be included in the TSP design depending on the power source. In some implementations, PFC can be used to correct for nonlinear loads that may require a power source. Both active and passive PFC stages are possible.

[0138] In some implementations, the ACG uses input power from the TSP and converts it into the desired high-frequency AC signal. In some implementations, the ACG is designed to improve the power transfer efficiency of the signal conversion unit. In some implementations, the ACG includes a power amplifier, an AC or RF generator, or an oscillator.

[0139] In some implementations, the primary power amplification stage of a power amplifier is either a "linear" stage or a "switching" stage. The trade-offs between these two architectures can include efficiency, power handling, and linearity. Example linear amplifiers can include Class A, Class B, and Class C. Example switching amplifiers can include Class D, Class E, and Class F. In some implementations, linear amplifiers have high linearity but low efficiency compared to switching amplifiers. Low efficiency can mean more difficult thermal management, higher component ratings, etc. Low linearity can mean increased harmonic content, potentially leading to regulatory compliance issues, reduced efficiency, more difficult physical and electrical layout design, etc.

[0140] In some implementations, ACG includes a full-bridge Class D amplifier. For example, the amplifier design utilizes a dual MOSFET transistor fed by a gate driver and a temperature-compensated crystal oscillator (“TCXO”) to generate the desired frequency. Figure 10AThis is a schematic diagram of an exemplary ACG subunit 1000 including a Class D amplifier 1010 with dual MOSFET transistors, a temperature-controlled quartz oscillator (“TCXO”) 1020 and a gate driver 1030. Figure 10B This is a theoretical schematic of an exemplary Class D amplifier using dual MOSFETs. In some implementations, a full-bridge architecture can provide differential (balanced) drive capability and four times the power output for a given bus voltage level at a given load, compared to a half-bridge architecture. Differential drive may also be relevant to emission compliance under balanced load conditions presented by the intended wing structure. Additionally, in some implementations, the Class D architecture can have a higher switching utilization factor compared to other switching architectures.

[0141] In some implementations, within a single-frequency driven Class D architecture, many input parameters can be modified to achieve improved output parameters. Example input parameters include dead time. Example output parameters include efficiency, peak component stress, etc.

[0142] In some implementations, Class D architectures can have high switching utilization factors and complete silicon-based component implementations, making them suitable for potential ASIC development. In such development, SoC (System-on-a-Chip) implementation is possible, where all control components and power electronics reside on the same die or MCP (Multi-Chip Package). In some implementations, Class D architectures have distributed modules housing the SoC and supporting circuitry at various distributed locations attached to given features of the aircraft.

[0143] In other implementations, alternative switching designs are utilized, such as single-switch architectures, like Class E or Class F. In some implementations, this architecture can be implemented at higher switching frequencies, where high-side gate drivers may be difficult or impractical. In some implementations, due to the potential limitations of Class D implementations at these frequencies, single-switch architectures can be used instead of Class D implementations as the frequency increases.

[0144] In some implementations, harmonic reduction and harmonic cancellation techniques can be used with switching amplifiers to mitigate any negative impacts from the nonlinear distortion inherent in some switching architectures. For example, changing the duty cycle of the fundamental waveform, blanking pulses, and other techniques can be used to remove harmonics during signal generation.

[0145] In some implementations, ACG includes transistors comprising silicon MOSFETs. In other implementations, the transistor is a gallium nitride (GaN) MOSFET. In certain implementations, GaN transistors have advantageous characteristics such as on-resistance, gate charge, and reverse recovery charge. In some implementations, GaN is suitable for higher frequencies.

[0146] In some implementations, the TSP additionally includes a low-power conversion (“LPC”) stage, such as a linear regulator, to draw power from an existing power supply and convert it into a power input signal suitable for driving components of the ACG, such as gate drivers or crystal oscillators. Figure 10C This is a schematic diagram of an exemplary ACG subunit 1050 including a Class D amplifier 1010 with dual MOSFET transistors, a temperature-controlled quartz oscillator (“TCXO”) 1020, a gate driver 1030, and an LPC 1060.

[0147] In some implementations, the AC generation subunit is located close to the target area. A potential advantage of this design is limiting losses and emissions that occur when carrying AC current from the AC generation subunit to the target area via the regulation network. In some implementations, the TSP subunit may be located close to the AC generation unit or close to an existing power supply or custom battery. When the TSP is closer to the ACG, it can be integrated with the ACG, potentially reducing the number of modules and its complexity in the system. When the TSP is closer to an existing power supply or custom battery, it can be designed to improve power delivery from the power supply or battery to the ACG (including improving efficiency and reducing EMI). For example, when an existing power supply provides power at 400Hz, 115VAC, the TSP can include an AC-DC converter to convert the supply voltage to 250VDC, thereby reducing EMI caused by AC current and improving efficiency by increasing the voltage and reducing the current carried from the TSP to the ACG.

[0148] In some implementations, the control subunit controls the status of the signal conversion units (including on / off modes, power output, frequency, and other parameters) based on relevant data inputs available in the application of the development device (heating system) and by outputting control signals to other signal conversion subunits (including drivers for the TSP and ACG). In examples of de-icing and anti-icing heating systems used in aircraft, in some implementations, data inputs may include manual pilot input from cockpit switches, temperatures from internal and external temperature sensors, wheel weight status from paddle switches, information from various aircraft logic units, information from avionics, feedback from the device (heating system) itself, and other data. In some implementations, the control subunit includes a microcontroller monitor fed by a low-power conversion (LPC) stage, such as a linear regulator, to draw power from the existing power supply and convert it into appropriate power input signals to output control signals to the TSP and ACG. Figure 11 This is a schematic diagram of an exemplary control subunit 1100 including a microcontroller 1110 and a low-power conversion stage (LPC) 1120.

[0149] In some implementations, such as in the case of a de-icing heating system converted for an aircraft, the signal conversion unit can be installed in a centralized location close to the available electrical bus. This reduces the complexity of unit installation, labor time, and cost. In other implementations, the signal conversion unit is decentralized and installed closer to the target area. This reduces the length of the AC signal that must travel between the signal conversion unit and the target area, potentially reducing the costs associated with electromagnetic interference (“EMI”) shielding of the signal and the cabling requirements for carrying such AC signals.

[0150] In some implementations, the heating system has an impedance regulation network (“IAN”) configured to regulate the output impedance of the heating system to a desired level. For example, the IAN may be configured to regulate the output impedance of the heating system to correspond to the input impedance of the bulk medium to be heated. For example, the IAN may be configured to regulate the impedance between the output of the heating system and the input of the bulk medium within a desired range. In some implementations, the impedance regulation network is configured to regulate the output impedance of the heating system to adequately match the impedance of the bulk medium. In other words, the matching network is configured to match the output impedance of the STU (“source”) to the impedance of the target area (“load”) within reasonable engineering tolerances. In some implementations, matching the source impedance and the load impedance includes adjusting the source impedance of the heating system to the complex conjugate of the impedance of the bulk medium. In some implementations, the impedance regulation network is adjusted such that the output impedance of the heating system is within 10% to 30% of the impedance of the bulk medium to be heated.

[0151] Figure 12 This is a conceptual diagram of the regulation network 1200 between source 1210 and load 1220. Figure 12 The regulation network is shown to obtain input power from the STU (“source”) through an input port that is impedance-regulated to the output of the STU, and to output the power to the target area (“load”) through an output port that is impedance-regulated to correspond to the target area.

[0152] Generally, for AC signals, when the output impedance of the source does not match the impedance of the load, a portion of the signal sent from the source to the load is reflected back to the source instead of traveling through the load. In some implementations, impedance regulation networks can achieve several benefits by suppressing signal reflections and voltage standing wave accumulation, including:

[0153] Voltage to reduce heating and arc risk

[0154] Improve the efficiency of the heating system

[0155] Reducing the total output power required by the STU reduces the size, weight, and cost of the STU.

[0156] Reduce stress on system components

[0157] Improve reliability

[0158] Reduce the temperature gradient in wiring and bulk media

[0159] In some implementations, the output impedance of the STU is higher than the impedance of the target region. In this case, the regulating network converts the relatively high voltage and low current power from the STU into relatively low voltage and high current power delivered to the target region. In this implementation, this means that the high current is delivered only after the regulating network, and therefore closer to the target, thereby reducing Joule losses in the rest of the SGU and improving the overall efficiency of the heating system.

[0160] In various implementations, the conditioning network can be centralized or distributed throughout the target area. Distributed conditioning networks can allow wiring to act as filters, potentially reducing the impact of peak voltage, peak current, and / or temperature on any given component. Distribution can also increase the modularity of the system design, which can improve component maintainability / replaceability. Additionally, distribution may allow the system to avoid sensitive equipment and / or hazardous areas (e.g., fuel tanks).

[0161] Distributed impedance regulation networks (such as impedance matching networks arranged at the inputs of coupling strip 1900) can facilitate localized distributed monitoring of each coupling strip, even in implementations where the power control system 104 supplies power to multiple coupling strips. Distributed impedance regulation networks can also provide components for various local capabilities, including the ability to turn coupling strip 1900 on or off, and the ability to communicate information to the power control system 104. Communication can be facilitated via separate communication cables or power cable encoding (e.g., via power cables connected to coupling strip 1900) to save weight and cable clutter.

[0162] For example, a distributed impedance regulation network can trigger a specific impedance state, which can be detected by the power control system 104 based on encoding the signal transmitted back on the power line using intentional impedance changes, for example, through digital communication encoding or analog or threshold level encoding techniques. As another example, the distributed impedance regulation network can add additional data signals to the power cable (in addition to the heating power signal). Alternatively or additionally, one or more of the units or elements mentioned as part of the heating system can relay information via wireless components.

[0163] In some implementations, the regulating network additionally supports fault indication. In these implementations, the heating system may include local fault sensors, as will be described in more detail below in the "Control and Sensing" section, which can be triggered or aggravated by a possible fault or failure in the heating system. For example, a local fault sensor may be positioned at coupling strip 1900. The regulating network may include a controller that maintains a lookup table specifying different types of faults in specific components and portions of the heating system, and different impedance values ​​corresponding to the types of faults. The regulating network can then be configured to adjust the input impedance of the regulating network as observed by the power control system to a specific value to indicate the possible presence of a particular type of fault or failure.

[0164] Additionally, in some implementations, the tuning network can be balanced by including additional capacitive elements and a grounded symmetrical midpoint. Balancing the network when driven by a fully differential source allows for high common-mode rejection and greater noise immunity. In some implementations, such balancing is not implemented, and the return path of the tuning network terminates at the circuit's ground terminal.

[0165] Generally, in some implementations, the regulating network may include passive electronic components arranged in a specific building block configuration. For example, these building block configurations may include transformers, L-networks, π-networks, T-networks, and other configurations.

[0166] In some implementations, the heating system's regulation network includes passive regulation subunits. Figure 14 This is a schematic diagram of an exemplary regulating network unit 1400 including a passive regulating subunit 1410. In some implementations, the passive regulating subunit may include one or more of the building block configurations described above, as well as other configurations assembled together. In some implementations, passive electronic components of the passive regulating subunits with high quality factors are selected to, for example, improve the efficiency of the network.

[0167] In some implementations, the conditioning network of the heating system can be designed with a high quality factor (high Q) or a low quality factor (low Q). High-Q conditioning networks can be used to filter out harmonic signal content. Filtering can be advantageous in switching amplifier designs because harmonic content can be higher for linear amplifiers. However, high-Q networks may be more sensitive to component tolerances, operational variations under external conditions, assembly variations, and any other changes in the system. Therefore, high-Q systems can present practical problems when implementing the system. For example, in the case of an aircraft wing de-icing system, if the system is high-Q, the impedance conditioning network may become highly uncoordinated due to small disturbances (such as flap movement), leading to a risk of failure. Reducing harmonic content beyond the fundamental drive frequency can be advantageous for regulatory approval and practical design issues, including including the inclusion of stray signals in the design, overstressing components (at peak or time-averaged ratings), and unstable control algorithms. In some cases, these sensitivity problems can be mitigated or even eliminated by using dynamically tuned elements.

[0168] In some implementations, the regulation network design of the heating system can be based on the concept of transmission line regulation. For example, the wiring at the input and / or output of the regulation network can be considered part of the regulation network. In some implementations, appropriate impedance regulation can be achieved by selecting the correct cable material, form factor, size, and length.

[0169] In some implementations, the heating system's regulation network is a dynamic regulation network that includes active regulation subunits and control subunits. Figure 15AThis is a schematic diagram of an exemplary regulating network unit 1500 including an active regulating subunit 1510 and a control subunit 1520. In some implementations, the active regulating subunit includes one or more regulating network configurations controlled by the control subunit. In some implementations, passive electronic components of the active regulating network subunit with a high quality factor are selected to, for example, improve network efficiency. In some implementations, the control subunit receives input data (such as forward power, reflected power, or voltage standing wave ratio) from signals sent to and from the target region and dynamically controls the active regulating network subunit to adjust impedance tuning in real time. For example, such control can be achieved by tuning elements included in the design of the active regulating network subunit. For example, dynamically tuning elements can include tunable capacitors and / or tunable inductors. Furthermore, examples of tunable elements include: PIN diodes, BST capacitors, DTC (discrete tuned capacitors), varactor diodes, MEMS, ferroelectric varactor diodes, ferromagnetic components, YIG tuned filters, etc. Exemplary metrics that can be considered when evaluating such devices include: operating frequency range, tuning DC voltage, tuning control signal linearity, control complexity, capacitor / inductor tuning ratio, tuning speed, quality factor (Q), switching life, package cost, power handling, power consumption, breakdown voltage, linearity, third-order intercept (IP3), integration capability, etc.

[0170] In some implementations, using a control unit with feedback between the target region and the regulating network allows the network to adapt to any external changes that may affect the impedance of the target region or the STU output impedance. These changes include variations in temperature, the geometry of the target region, the location of the heating system, the environment surrounding the system and the target region, and other parameters. In some implementations, the regulating network additionally includes a low-power conversion (“LPC”) stage, such as a linear regulator, to draw power from the existing power supply and convert it into a power input signal suitable for the control subunit. Figure 15B This is a schematic diagram of an exemplary regulation network unit 1550 including an active regulation subunit 1510, a low-power conversion stage (“LPC”) 1560, and a control subunit 1520.

[0171] In some implementations, specialized impedance measurements can be performed over a target region for all configurations and environmental conditions across the spectrum covering possible scenarios during the heating system's operation. These measurements allow for the design of dynamically adjustable network units suited to the narrowest impedance range, enabling adequate impedance regulation across the entire spectrum under the aforementioned conditions. In some implementations, this design is achieved through algorithmic optimization or computer simulation to improve system efficiency while reducing the weight, complexity, and cost of the regulating network.

[0172] In some implementations, dedicated cables can be used in the heating system. These dedicated cables are specifically designed or selected at each stage to improve efficiency and shield the power signals carried to the target area. Figure 16 This is a schematic diagram of the cable levels in an exemplary heating system. In various implementations, the cable levels in the heating system can be customized, including cables between the power supply 1620 and STU 1610 (first cable level 1630), cables in the STU between the TSP 1640 and ACG 1650 subunits (second cable level 1660), cables between STU 1610 and the conditioning network 1670 (third cable level 1680), and cables between the conditioning network 1670 and the target area 1690 (fourth cable level 1695).

[0173] Generally, various design considerations may be involved when designing dedicated cabling for the entire heating system. In some implementations, thermal considerations may be relevant. For example, in some implementations, the cabling connecting the regulating network to the target area (or in some cases, running near the target area and returning to the regulating network) is tightened to allow increased heat flow from the cable to the target area. This is advantageous because some of the heat generated when current flows through the cable (which would otherwise be lost) is recovered and transferred to the target area, where the purpose is to generate heat, thereby improving system efficiency.

[0174] In some implementations, cables can be routed near the target area using fasteners. To improve thermal contact in this case, a thermal interface material with improved thermal conductivity can be used to fill the air gap between the cable-fastener-target area interface.

[0175] In some implementations, the cable is directly attached to the target area. To improve thermal contact in this case, an adhesive with higher thermal conductivity can be used to attach the cable to the contact area. Additionally, a thermal interface material with higher thermal conductivity can be used to fill some or all of the remaining air gaps between the cable and the target area.

[0176] In some implementations, different cross-sectional geometries and cable shape factors can be used depending on the unit the cable connects to, the target area, or the power supply. In some implementations, the cable consists only of the main conductor, with or without a protective sheath (including for electrical insulation and / or environmental protection, such as corrosion, humidity, extreme temperatures, and friction). This configuration may be advantageous for parts of the system that will carry DC signals or deliver signals to a target area.

[0177] In some implementations, the cable is a coaxial cable. Coaxial cables may include shielding that reduces EMI emissions when carrying AC signals and prevents EMI around the system when carrying any signal.

[0178] In some implementations, the cable is a triaxial cable. This design can be beneficial for EMI protection and insulation when carrying any signal, more specifically, for example, when carrying a balanced signal at the output of a balanced implementation of a regulated network unit.

[0179] In some implementations, the cable is a biaxial cable. This design may offer similar advantages to those provided by triaxial cables.

[0180] In some implementations, different cable cross-sectional geometries can be used depending on the unit the cable is connected to, the target area, or the power supply.

[0181] In some implementations, the cable conductor has a circular geometry. With coaxial / triaxial / biaxial form factors, this design offers the advantage of relatively low manufacturing cost (low non-recurring engineering costs).

[0182] In some implementations, the cable cross-section is flat and / or rectangular. For example, this cross-section can be an advantageous cable geometry for the final stage of the system, where the cable delivers current to the target area. At this stage, a rectangular shape can allow for a lower impact of proximity and skin effects on the current circulating within the cable, thereby reducing losses and improving system efficiency. Additionally, this geometry can reduce the total amount of conductive material required in the cable, thus reducing system weight, an important consideration in the case of aircraft de-icing systems.

[0183] In some implementations, the size of the cross-section can be selected to limit the operating temperature to a specified range (e.g., for compliance and according to the material used to manufacture the cable) and to reduce its weight and size, depending on the specific input and output currents and signals carried by the cable and on its cross-sectional geometry and other factors.

[0184] In some implementations, different cable shielding types (and cross-sectional geometries) will be used depending on the unit, target area, or power supply to which the cable is connected.

[0185] In some implementations, the cable will not include any shielding. This may be more advantageous at stages that carry DC current (and therefore have lower EMI suppression requirements) and do not require a return path (e.g., later stages in systems where a return current is carried in the target area and nearby cables feed that current to the target area).

[0186] In some implementations, a single shield will be used. This is advantageous, for example, when a single layer of shielding is sufficient to make the cable meet EMI / EMC requirements and other environmental requirements.

[0187] In some implementations, double shielding will be used. This adds another layer of shielding, which can, for example, further reduce EMI emissions and reduce the EMI sensitivity of the cable.

[0188] In some implementations, triple or more shielding will be used. This adds an extra layer of shielding for reasons similar to those mentioned above.

[0189] In some implementations, for a given target area, the cable delivering current to that area may follow different possible paths.

[0190] In some implementations, the cables simply follow a roughly straight path from one side of the target area to the other. In some cases, these paths may be parallel. In some implementations, the cables may cross the target area diagonally, intersecting each other at different locations within the target area. This, for example, helps to generate more uniform heat on the surface of the target area and to create relatively hot spots at the desired locations where the cables intersect.

[0191] In some implementations, the cable travels along a zigzag path, a serpentine path, or a path that can be modeled using 2D spline curves. This design increases system efficiency by extending the path followed by the current flowing through the target region, thereby further increasing its effective resistance. For example, this can help achieve higher efficiency, lower current, and more stable system impedance regulation.

[0192] In some implementations, cable routing is designed based on a combination of the options listed above and other options.

[0193] In some implementations, different materials may be used in the manufacture of the cable, depending on its design, grade, and purpose.

[0194] Based on local voltage, current, temperature, power, bending radius, durability requirements, and other criteria, the conductor material of the cable can be selected to improve efficiency, conductivity, weight, cost, size, and thermal aspects.

[0195] In some implementations, the conductor material is made of copper, silver, aluminum, carbon fiber composites, titanium, or alloys thereof. In some implementations, the conductor is made of any of the aforementioned materials and coated with other materials, such as a silver coating, to improve the conductivity of the conductor's skin.

[0196] In some implementations, the conductors can be made of solid materials or stranded wires. For example, in some implementations, the stranded wires can be insulated from each other by using an insulating coating such as enamel. For example, Litz wires can be used to reduce the effects of skin effect and proximity effect within the cable.

[0197] In some implementations (e.g., for coaxial / triaxial / biaxial cables), the dielectric material of the cable can be selected to improve efficiency (e.g., by reducing dielectric loss), weight, cost, flexibility, maximum voltage tolerance, maximum power tolerance, and temperature rating (by tolerating higher temperatures and / or having higher heat capacity and / or lower dielectric loss and / or better external heat conduction of the cable) based on local voltage, current, temperature, power, bending radius, and durability requirements, as well as other criteria.

[0198] In some implementations of transmission line conditioning in conditioning network units, the associated cables may use dielectric materials that are also selected to achieve the desired impedance level. Exemplary materials include polyethylene and polytetrafluoroethylene, among others.

[0199] In some implementations, the cable sheath material is selected to improve parameters such as weight, cost, flexibility, maximum voltage tolerance, temperature rating, and thermal conductivity to nearby heat sinks (e.g., to the target area when used as a heat sink), based on local voltage, current, temperature, power, bending radius, and durability requirements, as well as other criteria.

[0200] In some implementations, where transmission line conditioning is used as part of a conditioning network, the length of the cable used for impedance conditioning can be controlled, in addition to its dielectric, to achieve a target impedance level. For example, the cable delivering current to a target area is used as part of a transmission line conditioning system, and extra length is added for impedance conditioning and the extra length is locally wound to occupy a smaller amount of space.

[0201] In some implementations, specific fastening techniques can be used to route cabling through the system's structure. This technique can be chosen to improve installation costs and time, system weight (by reducing the required wire length and the weight of the fastening technique), and to improve the desired electromagnetic effects and heat transfer of cabling near the target area.

[0202] In some implementations, fasteners are chosen to reduce the distance between the cable delivering power to the target area and the target area. This design can generate a stronger proximity effect. In other implementations, conventional cable fastener designs can be chosen for low cable-to-target area distances.

[0203] In some implementations, fasteners will also be used to increase heat conduction from the cable to the target area.

[0204] In some implementations, fastener materials are chosen for lower system weight and cost. This can be achieved by using, for example, composite materials. In some implementations that also use fasteners to conduct heat to the target area, materials are chosen for increased thermal conductivity (e.g., metallic materials typically have relatively high thermal conductivity).

[0205] In some implementations, an adhesive is chosen to attach the fastener to its mating area to increase strength and ensure long-term bonding to the target area. The strength of the adhesive is advantageous when the mating area is relatively small and the mechanical constraints created in the mating area are relatively strong. Additionally, in some implementations that use fasteners to conduct heat from the cable to the target area, an adhesive is also chosen to increase thermal conductivity.

[0206] Finally, in some implementations that use fasteners to conduct heat from the cable to the target area, a thermal interface material is used to fill the air gap in the area between the cable, the fastener, and the target area. This thermal interface material has sufficient thermal conductivity to ensure improved heat flow from the cable to the target area.

[0207] In some implementations, an adhesive is used to attach the cable directly to the surrounding structure (such as a bulk medium), allowing for better heat transfer from the cable to the structure to which it is attached. The adhesive is selected based on standards similar to those used for fasteners.

[0208] In some implementations, cable assembly designs involve splitting a given cable path into a set of two or more independent branches. This is useful, for example, in an implementation where a regulating network delivers current to a set of target areas. In such an implementation, a cable can be the sole output of the regulating network, and as it is routed to the target areas, the cable can be split into individual branches, each delivering current to the target areas. In some implementations, this splitting can be achieved by splitting a given conductor strand into several smaller conductor strands, by sending subsets of the strands to the individual branches when the split cable has stranded conductors, or by using a power divider. The power divider can be used to control the amount of current, voltage, and power flowing to the branches into which the cable is split.

[0209] Similarly, in some implementations, two or more cables can be combined into a smaller number of cables, which accumulate signals from all the combined cables. This combining can be achieved by merging given conductor strands into other strands, by regrouping different subsets of strands into new stranded cables, or by using a power combiner (e.g., a device similar to a power divider, but used backwards). The power combiner can be used to control the amount of current, voltage, and power flowing to the individual branches of the combined cables.

[0210] In some implementations, each cable level in the heating system has unique cable design considerations.

[0211] In some implementations, a first cable stage is selected to allow effective power transfer from the power supply to the TSP subunit. In some implementations where the power supply outputs DC current, the first cable stage comprises stranded copper insulated with an adapter material and having a total equivalent metering of power, voltage, and current suitable for carrying to the TSP subunit. In some implementations where the power supply outputs a 400 Hz, 115 VAC signal, the first cable stage comprises stranded wound copper insulated with an adapter material and having a total equivalent metering of power, voltage, and current suitable for carrying to the TSP subunit.

[0212] In some implementations, a second cable stage is selected to allow effective power transfer from the TSP to the ACG subunit. In some implementations where the TSP outputs power in the form of a 250 VDC signal, the second cable stage comprises stranded copper insulated with an adapter material and having a total equivalent metering of power, voltage, and current suitable for delivery to the TSP subunit.

[0213] In some implementations, a third cable level is selected and customized to allow efficient transmission of high-frequency AC power signals from the STU output to the conditioning network. For example, the cable may be designed to reduce resistance and electromagnetic losses caused by the high frequency of the signal, be shielded against external interference that could alter signal integrity, and prevent signal leakage from the cable that could affect surrounding equipment and materials. In some implementations, the third cable level is a high-power, high-frequency transmission line in the form of a customized coaxial cable. In some implementations, the coaxial cable includes: a core conductor that carries the input signal to the conditioning network and is made of stranded copper with an outer diameter large enough to carry power with reduced resistance loss; a dielectric material surrounding the selected core to increase electrical insulation and maintain a high voltage and temperature range; a shielding conductor providing a signal return path to the ACG, which is made of stranded braided copper with an equivalent metric large enough to carry power with reduced resistance loss; a first housing that insulates the selected conductive shield to maintain a high voltage and temperature range; an outer shield similar to the conductive shield but not directly carrying current and used to shield the cable from external interference and prevent leakage; and a final second housing similar to the first housing and insulating the outer shield.

[0214] In some implementations, a fourth cable class is selected and customized to allow efficient transmission of high-frequency and high-current AC power signals from the conditioning network to the target area. In some implementations, the cable is designed to regulate impedance between the conditioning network and the target area, reduce resistance and electromagnetic losses caused by the high frequency of the signal, and be shielded against external interference that could alter signal integrity, and prevent signal leakage from the cable that could affect surrounding equipment and materials. In some implementations, the fourth cable class is a high-power, high-frequency, and high-current transmission line in the form of a custom coaxial cable, similar to the aforementioned implementations of the third cable class, but with a larger conductor metering and diameter, and an additional silver coating on the same conductor to improve high-current performance and further reduce resistance losses. In some implementations, the fourth cable class is additionally customized based on the Litz wire design. This design aims to reduce losses due to proximity and skin effects in the cable by using branded conductors that are thinner than the skin depth, individually insulated (e.g., using an enamel coating), and with fully symmetrical wound braids.

[0215] Typically, electrodes comprise the material through which current enters and exits the target region of the bulk medium. In some implementations, connectors are used to attach the electrodes to the bulk medium. A connector is an attachment clamp that attaches the electrodes to the bulk medium. In some implementations, the electrodes and connectors are designed to reduce the contact resistance between the electrodes and the bulk medium. In other words, for a given return path, the electrodes are designed to smooth out potential differences that occur across the target region. If this contact resistance is higher than the resistance of the target region between the two electrodes, more heating will occur at the contact point than along the target region, all else being equal, thus reducing the heating efficiency of the heating system. In some implementations, for similar reasons, the electrodes and connectors are designed to reduce the contact resistance between the electrodes of the heating system and the wires (or cables). In some implementations, the electrodes and connectors are also designed to reduce electromagnetic losses (e.g., electromagnetic radiation).

[0216] In some implementations, electrode design considerations for achieving one or more of the above objectives include (1) selecting electrode materials with high conductivity and (2) increasing the “actual” contact area between the electrode and the bulk dielectric, and between the electrode and the wire. The “actual” contact area refers to the tiny metal-to-metal or material-to-material contact where current flows from one material to another, often referred to as the “point A”. In some implementations, connectors are also designed to achieve these objectives.

[0217] In some implementations, the electrode material may include silver, copper, aluminum, carbon fiber composites, titanium, or alloys thereof.

[0218] In some implementations, electrodes are part of a cable used to deliver current to the bulk medium.

[0219] In some implementations, the geometry of the electrodes is designed to suit specific target areas and / or reduce contact resistance between the electrodes and the bulk medium and / or reduce electromagnetic losses.

[0220] In some implementations, the electrodes are circular.

[0221] In some implementations, electrodes are the shape of the ends of cables used to deliver current to bulk media.

[0222] In some implementations, line electrodes are used (e.g., rectangular electrodes with a length greater than their width).

[0223] In some implementations, electrodes with a 2D spline curve shape and a small thickness (third spatial dimension) are used.

[0224] In some implementations, the cable conductor can be connected to the target area by being clamped between the connector plate and the target area. For example, a portion of the side of the connector plate that contacts the target area can be ground off. The conductor of the cable that is connected to the target area can be placed in this ground-off portion. This configuration allows the electrode connector plate to be clamped or attached to the bottom of the cable conductor without having to bend the connection to ensure proper engagement with the target area.

[0225] Generally speaking, various implementation and design considerations are expected for electrodes and connectors.

[0226] Figure 17 This is a photograph of an exemplary circular cylindrical electrode 1700 for use in a heating system 100. The electrode includes a circular grounding post coupled to a disk 1710 made of a conductive material (e.g., aluminum), on which a threaded conductive material 1720 (e.g., aluminum) is mounted.

[0227] In some implementations, the conductor of the cable connected to the target area via electrode 1700 is wound around threaded conductive material 1720, thus lying flat and covering most of the surface area of ​​both the threaded conductive material and the disc. In some implementations, nuts and washers may be used on the threaded material 1720 to press the conductor against the disc 1710, thereby ensuring a larger contact area and lower contact resistance.

[0228] In some implementations, the air gap between the gasket, cable, and disc 1710 is filled with a conductive and / or thermally conductive thermal interface material, thereby ensuring improved thermal and / or current conductivity from the cable to the post 1700.

[0229] In some implementations, a specially selected adhesive is used to attach the circular cylindrical electrode 1700 to the target area. This adhesive is sufficiently electrically and thermally conductive to conduct heat and electrical signals from the cable to the target area. In some implementations, the adhesive is also strong enough to withstand the torque generated by the nut and washer.

[0230] In some implementations, the connector is a U-shaped clamp that attaches to the bulk medium and the electrode in a manner that applies significant compressive strength between the electrode and the bulk medium.

[0231] In some implementations, the materials of the electrodes and connectors can be chosen to reduce their weight. In other implementations, in addition to reducing electrode weight, the electrode materials are chosen to improve electrical and / or thermal conductivity through the material. Improved conductivity is advantageous for electrode designs where current flowing from the cable to the target area passes through the electrode (e.g., circular cylindrical, a plate design).

[0232] In some implementations, a specific housing is included as part of the connector and electrode design. For example, such a housing may be selected for environmental qualification, including standards such as heat release and / or insulation, electrical insulation, EMI shielding, corrosion protection, vibration and shock resistance, durability, protection against external contamination and precipitation, etc.

[0233] Generally, various attachment configurations (and combinations thereof) are anticipated between the electrodes and / or connectors and the bulk medium. In some implementations, these configurations reduce the contact resistance between the electrodes and the bulk medium and / or reduce electromagnetic losses.

[0234] In some implementations, brazing joints are used to connect the electrodes to the bulk medium. Figure 18A This is a schematic diagram of an exemplary brazed joint attachment 1800 between electrode 1802 and a bulk medium target region 102 that is part of a larger bulk medium 1806. Brazing material is used to create the brazed joint 1804. For example, a low-temperature brazing filler metal (e.g., Al 802) can be used to braze the electrode to the target region to create a low-resistance contact. In some implementations, the filler metal is coated with flux to mitigate oxidation (forming an aluminum oxide layer at the brazed site). Flux is a material that dissolves oxides at high temperatures and prevents surface re-oxidation until the filler metal wets the surface.

[0235] In some implementations, the electrode and target region are bonded together under pressure and temperature. For example, in some implementations, a compressive force is applied between the electrode and the target region. Where it is not desirable to be bound by theoretical constraints, the compressive force can reduce the contact resistance between the electrode and the bulk medium according to the following equation:

[0236]

[0237] in H is the resistivity of the contact material, H is the Vickers hardness of the softer contact surface, and F is the compressive or contact force.

[0238] In some implementations, mechanical fastener connectors can be used to apply compressive force to connect the electrodes and the bulk medium. Figure 18B This is a schematic diagram of an exemplary attachment configuration 1820 between electrode 1802 and target region 102, which is part of a larger bulk medium 1806. Solid rivets 1822 are used to apply compressive force to attach the electrode to the target region.

[0239] In some implementations, a vacuum belt or a similar object that can seal the connection between the electrode and the target area can be used to apply compressive force. Figure 18C This is a schematic diagram of an exemplary attachment configuration 1840 between electrode 1802 and target region 102, which is part of a larger bulk medium 1806. An airtight seal tape 1842 is used to connect the electrode and the target region. After the airtight seal is completed, a suction device can be used to create a vacuum between the electrode and the target region, thereby binding them together and generating compressive force.

[0240] In some implementations, compressive force can be applied using clamps that hold the electrode and the target area and apply pressure at their interface, such as C-clamps.

[0241] In some implementations, a magnet or magnetized surface can be used to apply the compressive force. In some implementations, the face of the electrode or the face of the target region is magnetized, thereby allowing an attractive force between the magnet and the electrode and / or the contact area, which yields the desired compressive force. In some implementations, two or more magnets are used, with the electrode and the target region sandwiched between them, thereby allowing an attractive force between the magnets, which yields the desired compressive force. In some implementations, both the face of the electrode and the face of the target region are magnetized, thereby allowing an attractive force between the electrode and the target region, which yields the desired compressive force.

[0242] In some implementations, compressive force is applied by an external or internal compression clamp connector attached to a surface on or near the target area, and the adhesion strength is converted into the desired compressive force. In some implementations, an adhesive (e.g., a curing adhesive) may be used in conjunction with the clamp connector.

[0243] In some implementations, one or an alternative technique from the aforementioned methods can be used to partially or completely embed the electrodes into the bulk medium.

[0244] In some implementations, a conductive material (such as graphene) is placed between the electrode and the target region.

[0245] In some implementations, the connector material used to attach the electrode to the target area is an adhesive chosen for increased strength, thereby ensuring long-term bonding to the target area. The strength of the adhesive can be advantageous when the bonding area is relatively small and the mechanical constraint generated on the bonding area is relatively strong (e.g., in the case of a U-shaped columnar electrode). In one implementation, when the electrode needs to be held in place to cure the adhesive after application, internal or external / disposable clamps utilizing the adhesive and mechanical force can be used to hold the electrode in place.

[0246] In some implementations, the connector material used to connect the electrodes to the target area is also chosen for higher thermal and / or electrical conductivity to ensure improved flow of current and heat from the cable to the target area. For example, higher conductivity can be considered when attaching the electrodes such that the adhesive is in the current path flowing from the cable / electrode to the target area (e.g., with circular cylindrical electrodes and monolithic electrode designs). For this purpose, in some implementations, nanomaterials (e.g., CNTs) are placed between the electrodes and the bulk medium. In some implementations, the surfaces of the electrodes and a portion of the surface of the bulk medium that will contact the electrodes (e.g., the target area) can be manipulated to increase the “actual” contact area between them.

[0247] In some implementations, and in combination with the above and other implementations, a portion of the connector, electrodes, and target area is encapsulated with a material that reduces or eliminates electromagnetic losses.

[0248] In some implementations, any combination of the above methods can be used with any electrode and connector implementation. For example, Figure 18D This is a schematic diagram of an exemplary combined attachment 1860 between electrode 1802 and target region 102 of bulk medium 1806. The attachment includes brazed joint 1804 and solid rivet 1822.

[0249] In some implementations, the system may not require connectors / cables because physical contact is not needed to generate the desired current. In such cases, the signal return path may be an additional portion of the wiring returning to the conditioning network.

[0250] The heating system described herein can be used as a de-icing / anti-icing device to melt ice from aircraft surfaces by applying a high-frequency AC current to a target area of ​​the aircraft skin / fuselage (e.g., to generate Joule heating). The heat generated in the target area of ​​the fuselage is conducted to the fuselage surface and convection into the ice through the fuselage-ice interface. In some implementations, the ice melts completely. In some implementations, a portion of the ice (the layer in direct contact with the fuselage) melts, thereby forming a water layer between the ice and the fuselage, allowing the ice to slide off or be mechanically removed from the fuselage. In some implementations, heating occurs before the ice is present, thus preventing ice formation.

[0251] In some implementations, a high-frequency AC current continues to be applied as the ice melts to maintain the generation of Joule heating within the fuselage, where conduction and convection are used to transfer the Joule heating to any water that forms or remains on the surface.

[0252] Figures 19-32 Examples of components for carrying and delivering electromagnetic energy for a bulk medium heating system are provided. The component (referred to herein as a "coupling strip") is configured to function in conjunction with the bulk conductive medium to which the component is attached, similar to a transmission line. For example, in some implementations, the coupling strip is designed such that the bulk medium itself conducts current in a manner similar to current traveling through a transmission line. The coupling strip can electromagnetically couple an AC signal from a line to the bulk medium, thereby generating a corresponding current signal within the bulk medium. Therefore, it can be said, in practice, that the design of the coupling strip causes the bulk medium (in conjunction with the coupling strip) to also operate as a transmission line, or alternatively, that the bulk medium and the coupling strip together form a system that behaves similarly to a transmission line, and can be analyzed and designed in this way.

[0253] For example, as discussed above, implementations of the invention can be configured to generate heating in a bulk medium by manipulating mechanisms for shaping (e.g., contracting, elongating, etc.) the current within the conductive medium (e.g., a bulk medium, a conductor): for example, by using the skin effect and the proximity effect. Both effects rely on passing a high-frequency AC current through the conductive medium to be heated. The skin effect restricts current flow by utilizing the tendency of alternating current (“AC”) to distribute within the conductor, such that the current density is maximized near the conductor surface and decreases with increasing depth within the conductor. The proximity effect can be used to further restrict current flow in the conductor by placing another AC current path near the existing current flowing in the conductor. The proximity effect can also serve to elongate the current path. In addition to the systems and processes discussed above, coupling strips can be used to generate and control these effects. For example, coupling strips can be used with the various power control systems described above.

[0254] Figure 19This is a cross-sectional view of an exemplary coupling strip 1900. The coupling strip 1900 can be used to provide a high-frequency current signal to a bulk medium, such as an aircraft skin 1902, to heat the bulk medium. The coupling strip 1900 has a multilayer structure, including a first dielectric layer 1908 on the bulk medium 1902, a conductive layer 1904 on the first dielectric layer 1908, a second dielectric layer 1908 on the conductive layer 1904, and a conductive shielding layer 1906 on the second dielectric layer 1908.

[0255] The first dielectric layer 1908 has a thickness D1. The conductive layer 1904 has a thickness D2. The second dielectric layer 1908 has a thickness D3. The conductive shielding layer 1906 has a thickness D4. The total thickness of the coupling strip 1900 is D5. The conductive layer 1904 may be made of conductive materials including, but not limited to, copper, copper alloys (e.g., brass or bronze), silver, silver alloys, aluminum, aluminum alloys, titanium, titanium alloys, chromium, nickel, nickel alloys, cobalt-based alloys, corrosion-resistant steel, graphite, or combinations thereof. The conductive shielding layer 1906 may be made of conductive materials including, but not limited to, copper, copper alloys (e.g., brass or bronze), silver, silver alloys, aluminum, aluminum alloys, titanium, titanium alloys, chromium, nickel, nickel alloys, cobalt-based alloys, corrosion-resistant steel, graphite, or combinations thereof. In some implementations, the conductive shielding layer 1906 may be formed as a metal foil (e.g., copper foil or aluminum foil) or a braided metal layer. The dielectric layer 1908 may be made of dielectric materials including but not limited to Kapton, polyester film, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), rubber, or combinations thereof.

[0256] In some implementations, the coupling strip 1900 includes a protective layer on top of the conductive shielding layer. For example, the protective layer may include, but is not limited to, one or more layers of polyurethane, polyfluoride, coating, coating replacement film, sealant, or combinations thereof.

[0257] like Figure 20As shown, coupling strips 1900 may be arranged on the surface of a bulk medium, such as aircraft skin 2000 (e.g., a wing), to provide current to the bulk medium and heat it, thereby generating and shaping current flow within the bulk medium. The coupling strips 1900 extend along the surface of the aircraft skin 2000 and are spaced apart from each other. In some implementations, one or more coupling strips 1900 include a short-circuit terminal electrically coupling at least a portion of the coupling strip (e.g., conductive layer 1904) to the bulk medium 1902. For example, the coupling strip 1900 may terminate with an electrode, such as the electrode described above, to form a closed circuit (e.g., a short circuit) between the contained conductive layer 1904 and the bulk medium 1902. The terminating end of the coupling strip 1900 is the distal end of the strip opposite to the end providing current (e.g., opposite to the power input end). In some implementations, one or more coupling strips 1900 terminate with an open circuit. Open-circuit termination means that the termination of the coupling strip 1900 remains open; it is not connected to an electrical ground terminal through the bulk dielectric 1902 or the conductive shielding layer of the coupling strip 1900. In some implementations, one or more coupling strips 1900 terminate with an impedance conditioning component (e.g., a circuit element) connecting the coupling strip 1900 and the bulk dielectric 1902. For example, the coupling strip 1900 may terminate with a capacitor, resistor, or inductor terminal. For example, a circuit element such as a capacitor, inductor, or resistor may be connected between the conductive layer 1904 of the coupling strip 1900 and the bulk dielectric 1902.

[0258] refer to Figure 19 and 20 The power control system (e.g., the power control system 104 described above) is coupled to one end of each coupling strip to feed current to each strip. For example, power lines from the power control system may be coupled to the conductive layer of each carrier strip 1900, and one or two of the bulk medium 1902 (e.g., aircraft skin 2000) may be coupled to an electrical ground terminal.

[0259] The power control system provides AC current to each carrier strip 1900. For example, the power control system can provide AC current with a frequency between 1 kHz and 450 MHz. In some implementations, the frequency is between 1 MHz and 450 MHz. In some implementations, the frequency is between 1 kHz and 1 MHz. The power control system can be configured to provide AC current between 0.1 A and 200 A to each coupled strip 1900. For example, the power supply of the power control system and the electrical arrangement of the coupled strips 1900 can be configured to provide a desired amount of current (e.g., between 0.1 A and 200 A) to each coupled strip 1900. As a general example, if the coupled strips 1900 are coupled in series with each other to the power control system, a 100 A power supply can be used to provide 100 A of current to each coupled strip 1900. If ten coupled strips 1900 are coupled in parallel with each other to the power control system, a 100 A power supply can be used to provide 10 A of current to each coupled strip 1900. It should be noted that this example assumes that the impedances of all coupling strips are equal. As discussed below, the impedance of coupling strip 1900 can be adjusted in various ways to control the current distribution between the coupling strips, which may be desired or required for a particular heating application.

[0260] AC current for heating the aircraft skin 1902 is provided through the conductive layer 1904. For example... Figures 22A-22B As shown, the AC current provided by the conductive layer 1904 (e.g., coupled through an electromagnetic capacitor and an inductor) generates a corresponding current in the aircraft skin 1902. Figures 22A-22B This diagram shows the output of an electromagnetic finite element analysis (FEA) simulating the operation of an exemplary coupling strip 1900 attached to a conductive bulk medium 1902. The bulk medium 1902 (e.g., simulated as aircraft skin), conductive layer 1904, and conductive shielding layer 1906 are... Figure 22A The markings shown in the diagram. In Figure 22B In the figures, individual components of the coupling strip 1900 are not shown, and only the coupling strip 1900 (generally depicted) and the bulk medium 1902 are labeled. The area labeled 2206 in both figures represents the background environment (e.g., the atmosphere). These two figures show the normalized density (A / m²) of the current induced in the bulk medium 1902. 2 ), and is indicated by the shaded area 2204. The current density in the bulk medium 1902 is highest in a narrow region 2204 near the surface of the bulk medium 1902. Additionally, Figure 22AThe diagram illustrates the normalized electric field strength (light grayscale region 2202) within the dielectric layer of the coupling strip 1900. Notably, the conductive shielding layer 1906 shields the surrounding environment 2206 from the electric field generated by the current traveling through the conductive layer 1904, for example, to reduce or eliminate electromagnetic radiation and protect the coupling strip 1900 from external electromagnetic interference. The bulk dielectric 1902 also serves as a shielding layer by, for example, minimizing or blocking the electric field. Therefore, in the implementation of the coupling strip 1900, the conductive shielding layer 1906 and the bulk dielectric 1902 can be used to contain the electric field within the coupling strip 1900 (e.g., between the conductive shielding layer 1906 and the bulk dielectric 1902). This effect reduces or prevents electromagnetic interference between the heating system and other nearby electrical components. The implementation of the coupling strip 1900 incorporating the bulk dielectric 1902 can achieve operational performance comparable to a stripline transmission line.

[0261] Refer again Figure 19 The heating effect of the carrier strip 1900 on the bulk medium and the impedance of each carrier strip 1900 can be adjusted by changing characteristics such as: the thickness of each layer 1904, 1906, and 1908; the width of the conductive layer; the layout of the conductive layer; the material of each layer—including their dielectric constant and conductivity properties; or by including impedance adjustment components (e.g., capacitors, inductors, and resistors). Furthermore, as described above, the heating effect of the current generated in the bulk medium 1902 can also be altered by changing these characteristics, which are also used to adjust the proximity effect and path of the heating current traveling through the bulk medium 1902.

[0262] For example, layers 1904, 1906, and 1908 can be formed with corresponding thicknesses (D1-D4) typically between 0.1 mil and 1 inch, or in some implementations between 0.5 mil and 10 mil. In some implementations, the coupling strip 1900 can be formed at different distances separating the conductive layer 1904 from the bulk dielectric 1902 and from the conductive shielding layer 1906. In some implementations, these distances are ratio-dependent. For example, the coupling strip 1900 can be formed such that the relative thicknesses D1 and D3 of the dielectric layer 1908 are ratio-dependent. For example, for some implementations, the ratio D1:D3 can be in the range between 1:1 and 1:5. For other implementations, for example, to obtain the desired current density and / or impedance value for a given application, the ratio D1:D3 can be reversed to the range between 1:1 and 5:1. In one exemplary implementation, D1 is 3 mils, D2 is 1 mil, D3 is 3 mils, and D4 is 1 mil. In another exemplary implementation, D1 is 7.2 mils, D2 is 1.4 mils, D3 is 2.4 mils, and D4 is 1.4 mils. In yet another exemplary implementation, D1 is 1000 mils, D2 is 50 mils, D3 is 500 mils, and D4 is 50 mils. In yet another exemplary implementation, D1 is 10 mils, D2 is 2.5 mils, D3 is 50 mils, and D4 is 2.5 mils. In yet another example, D1 is 2.4 mils, D2 is 1.4 mils, D3 is 7.2 mils, and D4 is 1.4 mils. In yet another example, D1 is 17.6 mils, D2 is 9.8 mils, D3 is 24.5 mils, and D4 is 9.8 mils. In yet another example, D1 is 100 mils, D2 is 20 mils, D3 is 250 mils, and D4 is 20 mils. In yet another example, D1 is 5.5 mils, D2 is 2.5 mils, D3 is 9.0 mils, and D4 is 2.5 mils. In yet another example, D1 is 1.5 inches, D2 is 0.25 inches, D3 is 2.2 inches, and D4 is 0.25 inches. In yet another example, D1 is 3.8 mils, D2 is 2 mils, D3 is 3.8 mils, and D4 is 2 mils. In yet another example, D1 is 2.9 mils, D2 is 1.5 mils, D3 is 5.8 mils, and D4 is 2.5 mils. In yet another example, D1 is 5 mils, D2 is 2.5 mils, D3 is 25 mils, and D4 is 1.5 inches. In yet another example, D1 is 11 mils, D2 is 3 mils, D3 is 5.5 mils, and D4 is 3 mils. In yet another example, D1 is 21 mils, D2 is 1.5 mils, D3 is 7 mils, and D4 is 2.5 mils. In yet another example, D1 is 10 mils, D2 is 2.5 mils, D3 is 2 mils, and D4 is 2.5 inches.In yet another example, D1 is 4.5 inches, D2 is 0.25 inches, D3 is 1.5 inches, and D4 is 0.25 inches. In another exemplary implementation, D1 is 3 mils, D2 is 1 mil, D3 is 3 mils, and D4 is 1 mil. In yet another example, D1 is 10.2 mils, D2 is 3.5 mils, D3 is 40.8 mils, and D4 is 2.5 mils. In yet another example, D1 is 4.8 mils, D2 is 0.5 mils, D3 is 14.4 mils, and D4 is 0.5 mils. In yet another example, D1 is 15 mils, D2 is 1.4 mils, D3 is 3 mils, and D4 is 1.4 mils. In yet another example, D1 is 113 mils, D2 is 10 mils, D3 is 28.25 mils, and D4 is 10 mils. In another example, D1 is 127 mils, D2 is 5 mils, D3 is 254 mils, and D4 is 10 mils. In another example, D1 is 53 mils, D2 is 12 mils, D3 is 159 mils, and D4 is 12 mils. In yet another example, D1 is 13 mils, D2 is 1.4 mils, D3 is 2.6 mils, and D4 is 1.4 mils. In yet another example, D1 is 23 mils, D2 is 4 mils, D3 is 46 mils, and D4 is 4 mils. In yet another example, D1 is 11.5 mils, D2 is 2.8 mils, D3 is 57.5 mils, and D4 is 2.8 mils. In yet another example, D1 is 10 mils, D2 is 1.4 mils, D3 is 2.5 mils, and D4 is 1.4 mils.

[0263] In addition, the width of the conductive layer 1904 can typically range from a few inches to a few mils across the layer. Figure 21 Top views of several exemplary coupling strips (Examples 1-9) are depicted to illustrate various structures of the conductive layer 1904 within the coupling strip 1900. It should be noted that... Figure 21The coupling strip 1900 is depicted for illustrative purposes as removing the layer (e.g., a second dielectric layer and a conductive shielding layer) above the conductive layer 1904. The cross-sectional area of ​​the conductive layer 1904 may vary along its length. For example, the width of the conductive layer 1904 may vary along its length to adjust the impedance of the coupling strip 1900 and, in some cases, to adjust the current density in the bulk dielectric and the conductive layer. Examples 1-9 illustrate several exemplary width variation patterns of the conductive layer 1904 of the coupling strip 1900. For example, the width of the conductive layer 1904 across the coupling strip 1900 may vary between a maximum width and a minimum width. In some implementations, the maximum width is as small as 1.5 times the minimum width. In other implementations, the maximum width is as large as 100 times the minimum width. For example, the width of the conductive layer 1904 shown in Example 1 may be 1.5 inches at its maximum position (e.g., the top) and 1 inch at its narrowest position (e.g., the bottom). In another example, the width of the conductive layer 1904 shown in Example 1 may be 1 inch at its maximum position (e.g., the top) and 10 mils at its narrowest position (e.g., the bottom).

[0264] In some implementations, the thickness of the conductive layer 1904 can vary along its length. For example, the width of the conductive layer 1904 can vary along its length to adjust the impedance of the coupling strip 1900. In some implementations, the thickness and width of the conductive layer 1904, as well as the material, can vary along its length.

[0265] In some implementations, the impedance of the coupling line 1900 can be adjusted by including impedance adjustment components (e.g., capacitors, inductors, and resistors) at one or more locations along the length of the conductive layer 1904. For example, the conductive layer may be divided into segments along its length, with one or more impedance adjustment components connecting these segments. For example, see reference... Figure 21 In example 4 of the coupling strip, the conductive layer 1904 may be divided into two segments at region 2102, and impedance adjustment components (e.g., capacitors, inductors, resistors, or combinations thereof) may be electrically connected between the segments. Optionally or additionally, the impedance adjustment components may be connected to the conductive layer as shunt elements between the conductive layer 1904 and the bulk dielectric 1902 or the conductive shielding layer 1906.

[0266] In some implementations, the width, thickness, or both of the conductive shielding layer 1906 may vary along the length of the coupling strip 1900. In some implementations, the width, thickness, or both of the dielectric layer 1908 may vary along the length of the coupling strip 1900. For example, in some implementations, the cross-sectional areas of the conductive layer 1904, dielectric layer 1908, and conductive shielding layer 1906 may vary along the length of the strip 1900.

[0267] Figure 23Layout diagrams (layouts A-E) show several exemplary arrangements for the conductive layer 1904 within the coupling strip 1900. Initially, in (as...) Figure 21 In the depicted linear arrangement, the conductive layer 1904 extends linearly along the length of the coupling strip 1900. Layouts A-E depict the conductive layer 1904 arranged along a non-linear pattern or path of the coupling strip 1900. Specifically, Figure 23 The examples shown depict conductive layers 1904 arranged in various serpentine patterns. The depicted serpentine patterns position segments of conductive layer 1904 side-by-side with each other in the width direction of coupling strip 1900. This arrangement allows for a reduction in the overall length of coupling strip 1900 while maintaining the desired overall length of conductive layer 1904. In some applications, maintaining a relatively uniform length of conductive layer 1904 across different coupling strips 1900 helps to maintain consistent impedance between coupling strips 1900 of different lengths. For example, in both layout A and layout B, conductive layer 1904 can be formed with the same overall length. However, the overall length of coupling strip 1900 in layout B can be shortened (e.g., as shown in the original text). Figure 21 The length of the coupling strip 1900 with the linearly arranged conductive layer (as depicted) is half that of the coupling strip 1900. Similarly, the total length of the coupling strip 1900 in layout C can be shortened to one-third of the length of the coupling strip 1900 with the linearly arranged conductive layer. Furthermore, the shorter coupling strip 1900 can be placed in space-constrained locations on the aircraft body. For example, the coupling strip 1900 with the conductive layer arranged according to layouts A-E can be placed in a narrow region of the wing (e.g., the wingtip), where the coupling strip 1900 with the linearly arranged conductive layer may be too long to be suitable.

[0268] Layouts A through E illustrate coupling strips 1900 having conductive layers 1904 arranged along a non-linear path from input 2302 to termination 2304. Layout A illustrates a coupling strip 1900 having double-overlapping conductive layers 1904. The conductive layers 1904 in layout A include, for example, two segments arranged side-by-side in a U-shaped path from input 2302 to termination 2304. Figure 24A Depict a cross-sectional view of the coupling strip 1900 taken at A-A' according to layout A.

[0269] Layout B shows a coupling strip 1900 with a conductive layer 1904 arranged in a triple-overlapping configuration. The conductive layer 1904 in layout B includes, for example, three segments arranged side by side in an S-shaped path from input 2302 to termination 2304. Figure 24B Depict a cross-sectional view of the coupling strip 1900 according to layout B, taken at B-B'.

[0270] Layouts C and D illustrate coupling strips 1900 with different variations of conductive layers 1904 having a four-fold overlapping arrangement. The conductive layer 1904 in each of layouts C and D comprises four segments arranged side-by-side. In layout C, the segments of conductive layer 1904 are arranged, for example, in an M-shaped path (or W-shaped path) from input 2302 to termination 2304. In layout D, the segments of conductive layer 1904 are arranged, for example, in a double-overlapping arrangement folded along themselves. A similar technique can be applied to a triple configuration by folding a triple conductive layer 1904 along itself. Figure 24C Depict a cross-sectional view taken at C-C' of the coupling strip 1900 according to layouts C and D.

[0271] Layout E illustrates a more general arrangement of the conductive layer 1904. For example, layout E depicts an example of a conductive layer 1904 having multiple segments of varying widths positioned side-by-side with each other. Furthermore, in some implementations, as shown in layout E, the conductive layer 1904 may include interconnects 2306 between segments at various locations between the segments. In some implementations, the coupling strip 1900 may also include multiple signal inputs 2302.

[0272] Figure 25A A cross-sectional view depicts an exemplary configuration for attaching the coupling strip 1900 to the bulk medium 1902. More specifically, Figure 25A A bottom attachment configuration is depicted. In this configuration, an adhesive material 2502 is disposed between the bottom of the coupling strip 1900 (e.g., a bottom dielectric layer) and the surface of the bulk medium 1902. For example, the adhesive material may be, but is not limited to, a double-sided adhesive (e.g., double-sided tape), a layer of resin, or epoxy resin.

[0273] Figure 25B A cross-sectional view is depicted of another exemplary structure for attaching the coupling strip 1900 to the bulk medium 1902. More specifically, Figure 25B A top attachment configuration is depicted. In this configuration, an adhesive layer 2504 is applied to the coupling strip 1900 to attach the coupling strip 1900 to the aircraft skin 1902. The adhesive layer 2504 may be, for example, an adhesive coating, an adhesive film, or an adhesive tape.

[0274] Figure 26A This is a cross-sectional view of the coupling strip 1900 with a double-sided adhesive underlayer before it is installed on the bulk medium 1902, and Figure 26B It is installed on the bulk medium 1902 Figure 26AA cross-sectional view of the coupling strip 1900. In some implementations, such as a bottom attachment configuration, the coupling strip 1900 includes an adhesive underlayer 2608. The adhesive underlayer may be formed of a double-sided adhesive material (e.g., double-sided tape). In such an implementation, the double-sided adhesive material may be used as a bottom dielectric layer (e.g., ...). Figure 19 The bottom dielectric layer 1908. In some implementations, the adhesive underlayer 2608 may be, for example, an adhesive coating or adhesive film applied to the bottom surface of the bottom dielectric layer 1908. Before mounting, the coupling strip 1900 having the adhesive underlayer 2608 may include a pad 2610 on the adhesive underlayer 2608. The pad 2610 may be, for example, a release layer. For example, the pad 2610 may protect the adhesive underlayer 2608 before mounting. During mounting, the pad 2610 may be removed from the adhesive underlayer 2608 to expose its adhesive surface, allowing the coupling strip 1900 to attach to the surface of the bulk medium 1902.

[0275] In some implementations, one or more adhesive layers 2604 and 2606 may be included to attach the dielectric layer 1908 to the conductive layer 1904 and / or to attach the conductive shielding layer 1906 to the dielectric layer 1908. In some implementations, the coupling strip 1900 includes a protective layer 2602 on the conductive shielding layer 1906. For example, the protective layer 2602 may include, but is not limited to, one or more layers of polyurethane, polyfluoride, coating, coating replacement film, sealant, or combinations thereof.

[0276] In some applications, it may be necessary to heat a non-conductive bulk medium. In such cases, the heating system and coupling strip described herein can be modified to heat the non-conductive bulk medium. For example, an embedded layer can be used in conjunction with a coupling strip heating system to heat the non-conductive bulk medium.

[0277] Figures 27A-27F Cross-sectional views of various implementations of embedded coupling strips are depicted. Figure 27A Showing with Figure 19Coupling strip 2700 is similar to coupling strip 1900. Like coupling strip 1900, coupling strip 2700 has a multilayer structure, which includes a first dielectric layer 1908 on bulk dielectric 1902, a conductive layer 1904 on the first dielectric layer 1908, a second dielectric layer 1908 on the conductive layer 1904, a conductive shielding layer 1906 on the second dielectric layer 1908, and optionally a protective layer 2706 on the conductive shielding layer 1906. Protective layer 2706 is similar to the protective layer 2602 described above. The difference between coupling strip 2700 and coupling strip 1900 is that coupling strip 2700 is attached to the surface of non-conductive bulk dielectric 2702, and non-conductive bulk dielectric 2702 includes a bulk conductive material 2704 embedded therein. For example, the bulk conductive material 2704 can be formed as a metal foil, metal strip, or a braided metal layer embedded within the non-conductive bulk medium 2702. For example, the non-conductive bulk medium 2702 can be a layered material (e.g., carbon fiber composite, glass fiber composite, or Kevlar composite) in which the conductive bulk material 2704 is disposed between layers of the non-conductive bulk medium 2702. The bulk conductive material 2704 can be made of conductive materials including, but not limited to, copper, copper alloys (e.g., brass or bronze), silver, silver alloys, aluminum, aluminum alloys, titanium, titanium alloys, chromium, nickel, nickel alloys, cobalt-based alloys, corrosion-resistant steel, graphite, or combinations thereof.

[0278] exist Figures 27A-27F In the examples shown, the AC current flowing through the conductive layer 1904 of the coupling strip 2700 generates a heating current in the bulk conductive material 2704 rather than in the non-conductive bulk medium 2702. The heat generated in the bulk conductive material 2704 is then transferred (e.g., by conduction) to the non-conductive bulk medium 2702. In some examples, if the non-conductive bulk medium exhibits some conductive behavior, heat will also be generated in the non-conductive portion in addition to the bulk conductive material layer.

[0279] Figure 27B The diagram illustrates an implementation of a coupling strip 2700 comprising only a protective layer 2706, a conductive layer 1904, and a dielectric layer 1908. The coupling strip 2700 is arranged with the protective layer 2706 on the conductive layer 1904 and the conductive layer 1904 on the dielectric layer 1908. The dielectric layer 1908 is separated from the embedded conductive bulk material 2704 by a portion of a non-conductive bulk medium 2702.

[0280] Figure 27C An implementation of a coupling strip 2700 including a conductive layer 1904 embedded within a non-conductive bulk medium 2702 is shown. Figure 27CThe coupling strip 2700 includes a protective layer 2706, a conductive shielding layer 1906, a dielectric layer 1908, and a conductive layer 1904. The coupling strip 2700 has the protective layer 2706, conductive shielding layer 1906, and dielectric layer 1908 disposed on the conductive layer 1904. The conductive layer 1904 is embedded within a non-conductive bulk medium 2702 and spaced apart from the conductive bulk material 2704 by a portion of the non-conductive bulk medium 2702. For example, the conductive layer 1904 and the conductive bulk material 2704 may each be disposed between different layers of the non-conductive bulk medium 2702.

[0281] Figure 27D Show Figure 27C One form of the depicted coupling strip 2700, but without the protective layer 2706, the conductive shielding layer 1906, and the dielectric layer 1908.

[0282] Figure 27E Show Figure 27D One form of the depicted coupling strip 2700, but the conductive layer 1904 and the conductive bulk material 2704 are oriented in opposite directions. That is, in Figure 27E In the depicted arrangement of coupling strips 2700, the conductive bulk material 2704 is positioned closer to the surface of the non-conductive bulk medium 2702 than the conductive layer 1904.

[0283] Figure 27F An implementation of a coupling strip 2700 is shown, comprising a conductive layer 1904 and a conductive shielding layer 1906 embedded within a non-conductive bulk medium 2702. Figure 27F In the coupling strip 2700 arrangement depicted, a portion of the non-conductive bulk dielectric 2702 (e.g., a layer of the non-conductive bulk dielectric 2702) separates the conductive layer 1904 from the conductive shielding layer 1906 and the conductive bulk material 2704. The non-conductive bulk dielectric 2702 is used for... Figure 19 The dielectric layer 1908 in the coupling strip 1900 shown serves a similar purpose.

[0284] Figure 28A diagram illustrating the implementation of the coupling strip connector 2802 is shown. Figure 2805 is a circuit diagram of connector 2802. Connector 2802 includes an integrated impedance conditioning network 2804. Impedance conditioning network 2804 is electrically coupled between input signal interface 2806 and coupling strip 1900. For example, input signal interface 2806 may be a coaxial cable connection. Input terminal 2810 of input signal interface 2806 (e.g., the center wire of a coaxial cable connection) is coupled to conductive layer 1904 of coupling strip 1900 via wiring 2808. Ground terminal 2814 of input signal interface 2806 (e.g., shielding of a coaxial cable connection) is coupled to one or more of the bulk medium 1902 or conductive shielding layer 1906 of coupling strip 1900 via one or more wirings 2812, or both.

[0285] Impedance regulation network 2804 is configured to adjust the input impedance of coupling strip 1900 to a desired level as measured at input signal interface 2806. Impedance regulation network 2804 can be a fixed or variable impedance regulation network. For example, impedance regulation network 2804 can be implemented as described above. Figures 12-15B Any of the impedance regulation networks described. In Figure 2850, impedance regulation network 2804 is implemented as a shunt capacitor C1 connected between the ground terminal of either the conductive shielding layer 1906 of the coupling strip 1900 and the bulk medium 1902 (or, if implemented for a non-conductive bulk medium, a bulk conductive material 2704).

[0286] Figure 29 A diagram depicts another implementation of the coupling strip connector 2902. Connector 2902 includes, for example, two input signal interfaces 2906A and 2906B for coupling multiple coupling strips 1900 together. Figure 2905 is a circuit diagram of connector 2902. Connector 2902 includes an integrated impedance conditioning network 2904. Impedance conditioning network 2904 includes series shunt impedance conditioning components 2904A, 2904B, and 2904C electrically coupled between the input signal interfaces 2906A, 2906B and the coupling strips 1900. For example, input signal interfaces 2906A and 2906B can be coaxial cable connections. The corresponding input terminals 22910 of input signal interfaces 2906A and 2906B are coupled to the conductive layer 1904 of the coupling strips 1900 via wiring 2808 and are coupled to each other. The corresponding grounding terminals 2914 of the input signal interfaces 2906A and 2906B are coupled to one or both of the conductive shielding layers 1906 of the bulk medium 1902 or the coupling strip 1900 via one or more wiring 2912.

[0287] In Figure 2950, ​​the impedance adjustment network 2804 is implemented as a series connection between capacitor C1 and two shunt capacitors C2, C3 connected to ground of either or both of the conductive shielding layer 1906 and bulk medium 1902 (or bulk conductive material 2704 if implemented for a non-conductive bulk medium) of the coupling strip 1900.

[0288] Figure 30 This is a block diagram of a first exemplary bulk medium heating system 3000 utilizing coupling strips 1900 according to the present invention. The heating system 3000 includes a plurality of coupling strips 1900 spaced apart from each other and attached to a bulk medium 1902 (e.g., an aircraft wing). Each coupling strip 1900 is connected to a power control system 3002. The power control system 3002 can be implemented as any of the power control system 104 described above. The power control system 3002 feeds AC current to each strip.

[0289] One end of each coupling strip 1900 (referred to herein as the "input end") is coupled to the power control system 3002 via connector 3004. In the illustrated example, the opposite ends of each coupling strip 1900 (referred to herein as the "termination end") have either an open terminal 3006 or a closed terminal 3008. The coupling strips 1900 are arranged in an alternating pattern in which adjacent pairs of coupling strips 1900 have different types of terminals. For example, one coupling strip 1900 in each adjacent pair has an open terminal 3006 at its termination end, while the other coupling strip 1900 in the pair has a closed terminal 3008. The open terminal 3006 indicates that the termination end of the coupling strip 1900 remains open; it is not connected to the electrical grounding terminal through the bulk medium 1902 or the conductive shielding layer of the coupling strip 1900. In some implementations, closed-circuit terminal 3008 is a short circuit between the conductive layer of coupling strip 1900 and either the bulk dielectric 1902 or the conductive shielding layer of coupling strip 1900, or both. In some implementations, closed-circuit terminal 3008 is a capacitor terminal connected between the conductive layer of coupling strip 1900 and the electrical ground terminal. For example, a capacitor is connected between the conductive layer of coupling strip 1900 and the bulk dielectric 1902 or the conductive shielding layer of coupling strip 1900. In some implementations, closed-circuit terminal 3008 is an inductor terminal connected between the conductive layer of coupling strip 1900 and the electrical ground terminal. For example, an inductor is connected between the conductive layer of coupling strip 1900 and the bulk dielectric 1902 or the conductive shielding layer of coupling strip 1900. In some implementations, closed-circuit terminal 3008 is a resistor terminal connected between the conductive layer of coupling strip 1900 and the electrical ground terminal. For example, a resistor is connected between the conductive layer of the coupling strip 1900 and the bulk dielectric 1902 or the conductive shielding layer of the coupling strip 1900.

[0290] Complementary terminal types can be applied to adjacent coupling strips 1900 to provide a desired input impedance at the power control system 3002, provide a desired heating distribution across the bulk medium 1902, or a combination thereof. For example, coupling strips 1900 can be mounted on the bulk medium 1902 with adjacent coupling strips 1900 having complementary terminal types. For example, the terminals of adjacent coupling strips 1900 can alternate between open-circuit terminals 3006 and short-circuit terminals (e.g., closed-circuit terminals 3008 implemented as short-circuit terminals). In another example, the terminals of adjacent coupling strips 1900 can alternate between closed-circuit terminals 3008 implemented as capacitor terminals and closed-circuit terminals 3008 implemented as inductor terminals.

[0291] Figure 31 This is a block diagram of a second exemplary bulk dielectric heating system 3100 utilizing coupling strips 1900 according to an implementation of the present invention. The heating system 3100 is similar to the heating system 3000 described above, wherein the heating system 3100 adds a control system 3102 configured to drive variable terminals 3106 attached to the termination ends of each coupling strip 1900. The variable terminals 3106 include switchable terminals. In some implementations, the variable terminals 3106 are configured to switch between short-circuit terminals and open-circuit terminals. For example, the variable terminals 3106 include a controllable switch coupled between a conductive layer of the coupling strip 1900 and an electrical ground terminal. The controllable switch can be implemented as an electronic switch (e.g., a transistor, power diode, thyristor, silicon controlled rectifier, etc.) or a mechanical switch (e.g., a relay). For example, the controllable switch is connected between the conductive layer of the coupling strip 1900 and the bulk dielectric 1902 or the conductive shielding layer of the coupling strip 1900. The output of the control system is coupled to the control terminal of the controllable switch.

[0292] By opening and closing a controllable switch (or turning an electronic switch on and off), the terminals of each coupling strip 1900 can be changed between open and short circuit. For example, the control system 3102 controls the operation of the variable terminals 3106 of the coupling strip 1900 to heat the bulk medium 1902 by operating the controllable switch to change the terminal type of the coupling strip 1900 as needed. In some implementations, the control system 3102 can control the variable terminals 3106 of each coupling strip independently. In some implementations, the control system 3102 can control a group (e.g., a pair or a larger group) of variable terminals 3106 of coupling strips synchronously with each other. In some implementations, the control system 3102 can control one or more variable terminals 3106 of the coupling strip 1900 at regular intervals, for example, according to a regular operating cycle. The operating cycle used to switch the variable terminals 3106 can range from 0.01 Hz to 100 Hz.

[0293] In some implementations, the control system 3102 controls the operation of the variable terminal 3106 by alternately switching between open and closed terminals. For example, during the first half of the operating cycle, the control system 3102 switches half of the variable terminal 3106 to a short-circuit terminal and the other half to an open-circuit terminal. Then, during the second half of the operating cycle, the control system 3102 switches the variable terminal 3106 such that the open-circuit terminal is switched to a closed-circuit terminal, and vice versa. The operating cycle for switching the variable terminal 3106 can range from 0.01 Hz to 100 Hz.

[0294] In some implementations, the variable terminals 3106 of each pair of adjacent coupling strips 1900 are controlled to maintain terminals of opposite types. That is, the control system 3102 controls the variable terminals 3106 such that a terminal of one coupling strip 1900 in each adjacent pair is configured to be open, and a terminal of the other coupling strip 1900 in the pair is configured to be open, wherein the terminals alternate in every half operating cycle of the operating cycle.

[0295] The control system 3102 may be a computing device having one or more processors or microcontrollers configured to control the operation of the variable terminal 3106. For example, the control system 3102 includes a memory storing instructions (e.g., software code) that, when executed, cause the control system 3102 to provide appropriate control signals to the controllable switch in the variable terminal 3106. In some implementations, the power control system 3002 and the control system 3102 may be integrated into a common power and control system.

[0296] In some implementations, the variable terminal 3106 is configured to switch between a capacitor terminal and an inductor terminal. For example, a controllable switch can be arranged to switch between a capacitor whose conductive layer of coupling strip 1900 is coupled to a capacitor connected to ground and an inductor whose conductive layer of coupling strip 1900 is coupled to an inductor connected to ground. As described above, the ground terminal can be either the bulk dielectric 1902 or the conductive shielding layer of coupling strip 1900. Furthermore, in this implementation, the control system 3102 can operate as described above to alternately switch the variable terminal 3106 between conductive and inductor terminals.

[0297] In other implementations, the variable terminal 3106 can be modified to switch between different terminal types, such as switching between open-circuit terminals and capacitor terminals, switching between short-circuit terminals and inductor terminals, switching between open-circuit terminals and inductor terminals, switching between short-circuit terminals and capacitor terminals, switching between open-circuit terminals and resistor terminals, switching between short-circuit terminals and resistor terminals, or other combinations thereof.

[0298] Figure 32This is a block diagram of a third exemplary bulk dielectric heating system 3200 utilizing coupling strips according to the present invention. The heating system 3200 is configured to alternately drive adjacent coupling strips 1900. The heating system 3200 is similar to the heating system 3000 described above, wherein the heating system 3200 adds a control system 3202 configured to drive switchable connectors 3204 attached to the input terminals of each coupling strip 1900. The switchable connector 3204 includes a controllable switch arranged to connect and disconnect the associated coupling strip 1900 from the power control system 3002. The controllable switch can be implemented as an electronic switch (e.g., a transistor, power diode, thyristor, silicon controlled rectifier, etc.) or a mechanical switch (e.g., a relay). For example, the controllable switch is connected between the conductive layer of the coupling strip 1900 and the input terminal of the switchable connector 3204. The output of the control system is coupled to the control terminal of the controllable switch.

[0299] The control system 3202 controls the operation of the switchable connector 3204 to alternately connect and disconnect the coupling strip 1900 from the power control system 3002, thereby effectively turning the coupling strip 1900 on and off. For example, the control system 3202 can control the switchable connector 3204 to alternately turn the coupling strip 1900 on and off. For example, the control system 3202 can control the operation of the switchable connector 3204 of the coupling strip 1900 to heat the bulk medium 1902 by operating a controllable switch to turn the coupling strip 1900 on and off as needed. In some implementations, the control system 3102 can independently control the variable terminals 3106 of each coupling strip. In some implementations, the control system 3102 can synchronously control the variable terminals 3106 of a group (e.g., a pair or a larger group) of coupling strips. In some implementations, the control system 3102 can, for example, control the switching of one or more variable terminals 3106 of coupling strip 1900 at regular intervals according to a regular operating cycle. The operating cycle for switching the variable terminals 3106 can range from 0.01 Hz to 100 Hz. In some implementations, during the first half of the operating cycle, the control system 3202 turns on the coupling strip 1900 with open terminals 3006 and turns off the coupling strip 1900 with closed terminals 3008. Then, during the second half of the operating cycle, the control system 3202 switches the switchable connector 3204 to turn off the coupling strip 1900 with open terminals 3006 and turn on the coupling strip 1900 with closed terminals 3008.

[0300] The control system 3202 may be a computing device having one or more processors or microcontrollers configured to control the operation of the variable terminal 3106. For example, the control system 3202 includes a memory storing instructions (e.g., software code) that, when executed by the control system, cause the control system 3202 to provide appropriate control signals to the controllable switch in the variable terminal 3106. In some implementations, the power control system 3002 and the control system 3202 may be integrated into a common power and control system.

[0301] As used herein, the terms “perpendicular” or “substantially perpendicular” or “orthogonal” or “substantially orthogonal” refer to the relationship between two elements (e.g., lines, directions, axes, planes, surfaces, or assemblies) that form a 90-degree angle within acceptable engineering or measurement tolerances. For example, directions can be considered perpendicular to each other if the angle between them is within an acceptable tolerance of 90 degrees (e.g., ±1 to 2 degrees).

[0302] While this specification contains numerous details of specific implementations, these details should not be construed as limiting the scope of any invention or the scope that can be claimed, but rather as descriptions of features that may be specific to a particular invention. Certain features described in this specification in the context of individual implementations may also be implemented in combination within a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually in multiple implementations or in any suitable sub-combination. Furthermore, although features may be described above as functioning in certain combinations and even initially claimed in this way, in some cases, one or more features from the claimed combination may be removed from the combination, and the claimed combination may refer to a sub-combination or a variation of a sub-combination.

[0303] Similarly, although operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order shown or in sequence, or requiring all shown operations to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of the various system modules and components in the above implementation should not be construed as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated into a single software and / or hardware product, or packaged into multiple software and / or hardware products.

[0304] Specific implementations of the subject matter have been described. Other implementations are within the scope of the appended claims. For example, the actions described in the claims can be performed in a different order and the desired result can still be achieved. As an example, the processing depicted in the figures does not necessarily require the specific order or sequence shown to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous.

[0305] Control and Sensing

[0306] In some implementations, a controller is a set of sensors and circuits that perform control, sensing, and monitoring functions for a power control system. A controller can be, for example, as shown in the reference... Figure 1 The power control system 104 is described above.

[0307] In some implementations, control functions include turning the entire power control system on and off, turning on and off certain portions of the power control system designated to supply power to certain target areas of the bulk medium, and regulating the amount of power output to certain areas of the bulk medium.

[0308] In some implementations, the control function includes dynamically adjusting the control of the network.

[0309] In some implementations, monitoring functions include any combination of the following: assessing the health and adequacy of the entire heating system, assessing the health and adequacy of specific components and parts of the heating system, fault detection of the entire heating system, fault detection of specific components and parts of the heating system, notification of faults to one or more system users, and notification of faults to maintenance or inspection personnel.

[0310] In some implementations, fault detection means any combination of the following: detecting any electrical fault, detecting any heating function failure, detecting any coupling strip failure, or detecting damage in the bulk medium (including when the heating system is operating normally and undamaged). The coupling strip in this invention may also be referred to as a "strip line" or, in some cases, simply as a "line." The coupling strip includes, for example, those referenced above. Figure 19 and Figures 23 to 27F The aforementioned structural layer. As described below, in some implementations, the coupling strip may include multiple conductive paths, such as sensing lines and carrier lines. As used herein, a carrier line refers to a conductive path within the coupling strip that carries current for heating the bulk medium. A sensing line is a separate conductive path that can carry a smaller current for sensing faults in the overall carrier line or coupling strip, either intermittently or continuously.

[0311] In some implementations, electrical faults include, but are not limited to, levels of input and output power, voltage, and current at any stage of the power control system that are outside of the set interval. In some implementations, electrical faults include temperatures of circuits, devices, or components of the power control system that are higher or lower than the temperatures expected during normal operation of the heating system. In some implementations, electrical faults include levels of input and output impedance at any stage of the power system that are outside of the set interval.

[0312] In some implementations, heating function failures include, but are not limited to: overheating any area of ​​the bulk medium compared to normal operation of the heating system, and underheating any area of ​​the bulk medium compared to normal operation of the heating system. In implementations where the heating system is a de-icing system, heating function failures may also include any of the following: any area of ​​the bulk medium is not completely de-iced during or after de-icing and anti-icing operations, or freezing or refreezing of the bulk medium.

[0313] In some implementations, coupling strip failures include any of the following: temperatures at or near the coupling strip and at one or more locations on the bulk medium that are higher or lower than the temperatures expected during normal operation of the heating system; the coupling strip being cut at any location; short circuits within the coupling strip (between the trace and the shield or during trace inspection work); short circuits between the coupling strip and the bulk medium; short circuits and open circuits at the input connectors of the coupling strip; open circuits within the coupling strip; peeling in the coupling strip construction; coupling strip Burned portions of the strip; delamination between the coupling strip and the bulk medium; peeling of the coupling strip from the bulk medium; mechanical damage such as dents, holes, protrusions, cuts, wrinkles, burrs caused by events such as hail, lightning strikes, mishandling of the coupling strip by maintenance personnel or other personnel, walking or stepping on the coupling strip by maintenance personnel or other personnel, electrostatic discharge, corrosion of the coupling strip, corrosion or oxide film between the coupling strip and the bulk medium or between the electrode / connector and the coupling strip or between the electrode / connector and the bulk medium.

[0314] In some implementations, the sensing functionality includes all the sensors used to provide input and feedback to the controller, such as voltage, current, power, forward power, reflected power, voltage standing wave ratio (VSWR), time domain reflectance (TDR), temperature, and ice sensors.

[0315] In some implementations, some or all of the controller's components are distributed within the power control system. In some implementations, some or all of the controller's components are mounted so that they are independent of the rest of the control system. In some implementations, these elements are housed in a separate, dedicated enclosure.

[0316] In some implementations, two or more components of the controller are independent of each other and configured such that failure of the controller's function requires the simultaneous failure of at least two of these components. In such implementations, the controller's reliability is increased due to its independence from each other, and the lower reliability required to meet the controller's requirements from the individual components makes their design, implementation, and integration easier and simpler in some cases. This is particularly advantageous in applications where safety and controller reliability are critical or regulated (especially in the case of heating systems mounted on aircraft).

[0317] In some implementations, two or more subsystems performing monitoring functions are independently configured to help achieve reliability and safety requirements. In some implementations, two or more subsystems performing sensing functions are independently configured to help achieve reliability and safety requirements. In some implementations, two or more subsystems performing control functions are independently configured to help achieve reliability and safety requirements. In some implementations, any combination of control, sensing, and monitoring subsystems is independently configured to help achieve reliability and safety requirements.

[0318] In some implementations, two identical sensors are used at certain sensor locations. In such implementations, the two sensors can be connected to the same monitoring subsystem and feed data to that subsystem. For example, each of the two sensors can be connected to a separate monitoring subsystem configured to operate independently of the others, or each of the two sensors can be connected to two or more monitoring subsystems configured to operate independently of the others.

[0319] In some implementations, two independent sensors are used to collect information about similar areas, and independence can be achieved by using different sensor types and / or by placing them at least some distance from each other while still being able to monitor the same area or collect equivalent information. In such implementations, the two sensors can be connected to and feed data to the same monitoring subsystem, each sensor can be connected to a separate monitoring subsystem configured to operate independently of each other, and each sensor can be connected to two or more monitoring subsystems configured to operate independently of each other.

[0320] In some implementations, any combination of the controller's control, sensing, and monitoring subsystems is configured to optimize the reliability and safety of its most critical functions. In the case of heating systems used for aircraft de-icing and anti-icing, in some implementations, such functionality may include a combination of: detecting any heating system malfunctions and notifying the pilot of these malfunctions; detecting electrical malfunctions in the power control system and notifying the pilot of these electrical malfunctions; detecting any malfunctions in the coupling strip; and detecting any heating malfunctions in the power control system and the bulk medium and notifying the pilot of these heating malfunctions.

[0321] In some implementations that use heating systems for aircraft de-icing and anti-icing, the controller is further optimized to verify that critical aircraft surfaces remain free of freezing or already frozen precipitation and contaminants once de-iced. Contaminants can refer to sleet, snow, mud, ice, or any other material that may adhere to the aircraft skin and impede proper operation.

[0322] In some implementations, the coupling strip layout of the controller and the bulk medium is designed and optimized to work together. In such implementations, the coupling strip layout on the bulk medium can be arranged to create regions of interest at selected locations. These regions could be, for example, areas designed to remain cooler than the rest of the bulk medium when the heating system is activated, or areas that are likely to experience a refreezing event first (e.g., due to ongoing or frozen precipitation, or due to melted contaminants running on the surface of the bulk medium) while the heating system is running or after the heating system is deactivated. In such implementations, the controller's sensors can be arranged to collect information about these regions and help assess whether the heating system is operating adequately or whether the bulk medium is experiencing a freezing or refreezing event. In some implementations, the bulk medium can be locally modified at some of these regions to ensure that these regions are cooler than other areas of the bulk medium when the heating system is running, or to ensure that these regions are the first to experience a refreezing event (e.g., by adding relatively small features such as edges and ridges so that melted water may accumulate and clog the cooler areas to promote refreezing). In some implementations, these areas are selected to be easily observable by the user of the heating system (e.g., in the case of an aircraft de-icing system, easily visible to the pilot from the aircraft cabin or cockpit), allowing the user to infer whether the bulk medium has undergone a de-icing event based on visual observation of the area.

[0323] In some implementations of heating systems used for aircraft de-icing and anti-icing, the controller is further optimized to verify that specific areas are free from freezing or already frozen precipitation and contaminants. Such areas may include: horizontal and inclined upper surfaces exposed to vertical and near-vertical falling precipitation, and the upper surfaces of wings and horizontal stabilizers.

[0324] In some implementations, some of the monitoring functions are performed by analyzing data collected by the sensing subsystem using machine learning, computer vision, and artificial intelligence techniques. In such analyses, in some implementations, these techniques can be trained using data empirically collected from tests conducted on the heating system, and can be continuously trained and improved using data collected from the installed heating system.

[0325] In some implementations, the controller can use timers to measure time information, such as the activation time of the heating system, the amount of time elapsed since the heating system was last activated, and the amount of time elapsed since the system was last deactivated. In some implementations, information from the timers can be used in conjunction with information from the sensing subsystem for analysis to help the controller perform its intended function.

[0326] like Figure 37A As shown, a cockpit display and notification system may be provided in some implementations. This system may have multiple indicators that inform the pilot of the system's status. For example, an "ON" indicator may illuminate when the system is powered on, and a "WARM" indicator may illuminate when some or all of the necessary temperature sensors are at or above 15°C. For example, an "OK" indicator may illuminate when some or all of the necessary temperature sensors have indicated a temperature at or above 15°C for at least 15 minutes. An "OVHT" indicator may illuminate if an overheating condition is detected (e.g., any temperature sensor reaches a temperature greater than or equal to 150°C). A "System Failure" indicator may illuminate for various reasons indicating a potential system failure. For example, the system may have been "on" for a predetermined time (e.g., 25 minutes) without reaching at least the "WARM" state. In another example, a "System Failure" indicator may illuminate if the system is "ON" and has been in the "OVHT" state for more than 10 seconds. The aforementioned temperatures and times are provided for illustrative purposes, and these temperatures and times can be changed or adjusted without departing from the scope and spirit of the invention.

[0327] Figure 37B Alternative example cockpit instructions are depicted, showing the system functionality status of the "DE-ICE" and "ANTI-ICE" systems. In the example illustration, the cockpit instructions can indicate whether the system is in an "OFF," "GROUND DE-ICE," "GROUND ANTI-ICE," or "FAULT" state. In some implementations, separate instructions may be presented for each zone of the aircraft or area of ​​concern.

[0328] Figure 37C Show Figure 37B The cockpit instructions can be implemented in an example located within the aircraft cabin. Figure 37C In the example shown by the dashed box, the cockpit indicator is located in the upper right corner of the cockpit above the aircraft.

[0329] In some of the above implementations, the controller's sensing subsystem may include one or more wireless sensors (e.g., one or more wireless temperature sensors or one or more wireless ice sensors) configurable to transmit data to a central receiver via a wireless data network. This reduces the need for additional sensor wires and enables access to various physically distant locations on the bulk medium. The wireless sensors may draw power from the coupling strip 1900 via a direct electrical connection (e.g., by accessing a low-voltage, low-current DC bias carried in the coupling strip 1900, or directly from the AC current passing through the coupling strip 1900). Alternatively, the wireless sensors may draw power without a direct connection to the coupling strip 1900 (e.g., by accessing near-field electromagnetic emissions via an antenna or coil).

[0330] Temperature sensing

[0331] In some implementations, the controller's sensing subsystem includes a temperature sensor. The temperature sensor can be used to make point measurements, or, for example, to measure parameters such as the maximum, minimum, average, or mapping of the temperature over a given area by using a sensor pad with multiple sensors that can extract information about that area.

[0332] In some implementations, temperature sensors can include any of the following sensor types: thermocouples, resistance temperature detectors (RTDs), thermistors, fiber optics, and infrared sensors. Thermocouples can be used to measure temperature by measuring changes in voltage. Thermocouples are inexpensive, simple to implement, and have a wide measurement range. The signal is approximately tens of millivolts, which may require significant noise reduction for accurate measurements in the presence of electromagnetic interference. Resistance temperature detectors (RTDs) can be used to measure temperature by measuring changes in the resistance of the sensor. These elements are typically made of platinum and have very high accuracy. This may require four-wire measurements or the leads must be kept short (e.g., by implementing local voltage measurements (which are then converted to digital signals)). Thermistors are similar to RTDs because both are based on resistance measurements to calculate temperature. Thermistors have the added advantage of high baseline resistance, which may make lead resistance negligible. Fiber optic sensors are typically based on fiber Bragg gratings. The grating reflects light of a specific wavelength. As temperature changes, the reflected wavelength changes predictably, making it possible to calculate the temperature. Because each grating reflects only a small band of wavelength, multiple sensors can be integrated into a single fiber optic element and measured using a single instrument. The fiber optic element itself has a very small diameter (~0.1 mm), but its length can be several meters or tens of meters. Since the measurement is optical, it should be unaffected by RF interference.

[0333] In some implementations, temperature sensors are arranged on the bulk medium in the manner described above in this specification. In some implementations, supported by a lumped capacitance model, temperature sensors may be arranged widely spaced, beneath the skin of the bulk medium, or both. This lumped capacitance model assumes that the temperature of the solid is spatially uniform within a volume where the Biot number Bi is sufficiently small (e.g., Bi < 0.1), where the Biot number is defined as… Where k is the thermal conductivity of the solid, h is the convective heat transfer coefficient from the solid to its surroundings, and L is the characteristic dimension of the volume. The lumped capacitance model can be particularly useful because within a sufficiently small volume of Bi, the temperature of the bulk medium can be assumed to be approximately uniform, allowing for a reduction in the number of sensors mounted on the bulk medium, thereby reducing system complexity, cost, and installation labor. This technique is particularly effective for bulk media with high thermal conductivity (such as aluminum alloys commonly used to form aircraft skin), where the number of Biots remains sufficiently small over a relatively large area, justifying the use of a limited number of temperature sensors and sensing points. In some implementations, temperature sensors can be arranged on the bulk medium, such as at specific locations (e.g., hot spots, cold spots, refreezing points, and other points). Hot spots can be locations selected as operating relatively hotter than other locations on the bulk medium when the heating system is activated. Hot spot sensors can be used for general controller functions and can also be used to detect over-temperature events on the bulk medium or coupling strips. A cold spot can be a location selected when the heating system is activated, indicating that it operates relatively colder than other locations on the bulk medium. A cold spot sensor can be used for general controller functions and to detect underheating on the bulk medium or coupling strip. A refreeze point can be a location selected when the heating system is activated or after the heating system is deactivated, indicating that it is more likely to experience a freezing or refreezing event more quickly than other locations on the bulk medium. A refreeze point sensor can be used for general controller functions and to detect refreezing events or underheating on the bulk medium or coupling strip. Other points can be located in other areas of interest, such as those previously listed in this specification.

[0334] In some implementations, the layout of the coupling strips on the bulk medium can be optimized so that the area containing the aforementioned points is a designated area selected based on parameters such as ease of user access, ease of installation, or ease of visual observation of the heating system. For example, such as Figure 33 As shown, the aircraft pilot has a limited line of sight 3302 visible from the cockpit. This results in an invisible portion (3304) and a visible portion (3306) of the aircraft for the pilot. In some implementations, a refreeze point or cold spot may be selected within the visible portion (3306) of the aircraft to permit visual verification by the pilot.

[0335] Figure 33 An example temperature coverage of the wing when the system is activated is also shown. Position 3308 on the wing may be selected or designed to be visible to the pilot and monitored to allow for verification of anti-icing examples before takeoff. For example, as shown, position 3308 is associated with a relatively cold region (as shown by the yellow gradient) compared to the majority of the wing (as shown by the red gradient) within the heating mode generated by heating elements (such as the coupling strips described herein).

[0336] The locations of cold and / or hot spots can be designed, for example, by arranging heating strips (e.g., coupling strips) on the surface of the aircraft in a heating pattern that produces a locally cooler or warmer skin temperature relative to the rest of the aircraft. For example, the coupling strips can be arranged with a geometry that provides locally lower (or higher) power density (greater wire spacing), or the selected coupling strips can operate at lower (or higher) power density at locations with higher (lower) thermal mass, or by locally adjusting the output power to produce a heating pattern that provides cold / hot spots at desired locations.

[0337] In some implementations, at least two independent sets of temperature sensors can be used to improve the reliability of critical controller functions by adding redundancy to their sensing subsystems. In some implementations, independence can be achieved by adding two identical temperature sensors at each designated sensor location. In some implementations, independence can be achieved by adding two different temperature sensors (e.g., from different manufacturers or of different sensor types) at each designated sensor location. In some implementations, independence can be achieved by adding two temperature sensors at locations sufficiently far apart to reduce the likelihood of simultaneous sensor failure while being close enough to monitor equivalent parameters. In some implementations, independence can be achieved through any combination of these methods. In some implementations, the independent sensor sets can send information to a single monitoring subsystem, or to separate sets of monitoring subsystems each dedicated to their respective independent sensor sets, or all to at least two separate sets of monitoring subsystems.

[0338] In some implementations, for example, temperature sensing can be achieved by using one or more temperature sensors (or temperature elements) as an integral part of a coupling strip, in addition to or instead of using a temperature sensor separately arranged on the bulk medium. An example temperature sensor is described in more detail above in the temperature sensing section. For example, the temperature sensor can be fixed to the coupling strip or a nearby sensing line (described in more detail below) and can be short-circuited or open-circuited when the temperature exceeds a predetermined threshold. The short circuit or open circuit can be detected at other locations (e.g., at the input connector or in the power control system (e.g., system 104)). This makes temperature detection possible at the location of the temperature sensor.

[0339] In some implementations, arrays of temperature sensors can be arranged in parallel. For example, a parallel arrangement may include an array of parallel over- or under-temperature sensors arranged as a thermostat control loop. The thermostat control loop is used to control the system (e.g., by utilizing temperature sensor information) Figure 1 A hysteresis control method for maintaining the temperature of the heating system 100 within a predetermined range (e.g., above the minimum temperature Tmin and below the maximum temperature Tmax).

[0340] In some implementations, the array of temperature elements can be arranged in series. For example, the temperature elements can be arranged along a coupling strip 1900 (e.g., fixed to the coupling strip or nearby sensing line) or along a separate cable strip to force an over-temperature shutdown if the temperature becomes too high at any point in the series configuration.

[0341] In some implementations, temperature elements such as periodic thermistors with different values ​​can be arranged in parallel, so that when a particular temperature element along the line is overheated, the analog value can be detected and decoded to indicate not only that the coupling strip has been noticed to be overheated, but also that a particular location along the coupling line has failed.

[0342] In some implementations, temperature sensing can be achieved by using traces on a flexible circuit, using additional sensing lines within the coupling strip and extending along the carrier line (the sensing lines serve as wiring from and toward the temperature sensor implemented within the coupling strip), using additional sensing lines and sensors implemented in a sensing strip mounted independently of the coupling strip, or by directly implementing the temperature sensor in the coupling strip using the carrier line, for example, in a configuration of a periodic capacitor, a parallel plate capacitor, a trace inductor, or a combination thereof.

[0343] In some implementations, temperature can be measured as a function of time. For example, temperature changes can be measured and recorded at regular sampling intervals and stored as a vector representing time-based temperature changes, rather than a static temperature measurement. Time-based temperature measurements allow for more complex mathematical analyses, such as rates of change (e.g., time-based derivatives) or total heat output (e.g., integrals). In such implementations, the controller can perform any of a variety of evaluations, including assessments of the current de-icing status based on time information associated with temperature changes. As a specific example, in response to a temperature reading sensed by a temperature sensor hovering around 0°C, the controller can determine that energy supplied by the bulk medium heating system is entering the latent heat of melting, and therefore de-icing is in progress. Furthermore, when the temperature reading sensed by the sensor increases after hovering around 0°C, the controller can determine that the de-icing operation is complete because once the frozen contaminant has melted from the bulk medium, the energy supplied by the bulk medium is used to raise the temperature rather than entering the latent heat of melting. In other words, when the temperature of the reference time plot has been relatively flat (e.g., zero slope) for a predetermined period of time, followed by a period of positive slope, the point in time when the block medium is de-iced can be determined.

[0344] In some cases, as will be further explained in the “Ice Detection / Sensing” section below, temperature can also be measured as a function of time and can be used to estimate de-icing conditions in a similar manner.

[0345] Figure 40 A plot of impedance versus temperature as a function of time is shown on the coupling strip. As shown in plot 4000, during the de-icing operation (from approximately 07:00 to 07:30), the temperature reading hovers around a fixed value (10°C), and then increases as the de-icing operation is completed (starting from approximately 07:30).

[0346] Additionally, in implementations where the bulk medium is composed of a highly thermally conductive material (e.g., aluminum), a lumped capacitance thermal model can be used as the basis for evaluating the system's de-icing performance. The controller can also use the lumped capacitance thermal model to determine the location and temperature of any cold spots on the bulk medium. This can reduce the total number of sensors required by leveraging the thermal conductivity of the bulk medium, facilitate more efficient sensor placement (including placing sensors under the aircraft skin (rather than on top)), or both.

[0347] Ice detection / sensing

[0348] In some implementations, the controller's sensing subsystem includes ice detectors or sensors. Ice detection refers to methods for identifying freezing or frozen precipitation or contaminants (including, but not limited to, snow, ice and meltwater, or similar forms of frozen precipitation accumulated on surfaces).

[0349] In some implementations, ice detection is used to determine whether de-icing of the structure is needed, to track and monitor the progress of de-icing, and to monitor subsequent ice buildup after de-icing.

[0350] In some implementations, ice detection is achieved using one or more transducers to monitor the acoustic parameters of the structure, including but not limited to damping coefficients, resonant frequencies, and frequency responses. In some implementations, ice detection is achieved by observing changes in polarized light. In some implementations, changes in incident unpolarized light are observed after it interacts with ice using variable polarization. In some implementations, changes in incident polarized light are observed. In some implementations, changes in the intensity of reflected light can be used to detect ice formation. In some implementations, ice is detected using one or more sensors on a surface where snow / ice is collected. When snow or ice accumulates on top of the surface, it closes the sensor aperture, indicating the presence of ice. In some implementations, infrared emission from the surface can indicate the presence of ice. This includes, but is not limited to, changes in surface emissivity and calculating surface temperature to determine if conditions are favorable for ice formation. In some implementations, ice detection can be achieved using sensors mounted on critical surfaces. When freezing or already frozen precipitation accumulates on the sensor, this results in a measurable change in impedance. In some implementations, ice sensors utilize the fact that the presence of ice near the coupling strip will affect the electromagnetic field around the line, thus having a detectable effect on the frequency domain and / or time domain response of the coupling strip to an electrical signal. These changes can be measured and used to indicate the presence of ice on the structure. In some implementations, the presence of ice can be predicted by a temperature gradient on the structure or by a rate of temperature change, which can be measured using a temperature sensor as described above. In some implementations, any of the sensors described herein can be surface-mounted to the structure.

[0351] In some implementations, ice sensors are arranged on the bulk medium, similar to how temperature sensors can be arranged as described earlier in this specification. In some implementations, ice sensors may be arranged on the bulk medium, such as at specific locations (e.g., hot spots, cold spots, refreezing points, and other locations). Hot spot sensors can be used for general controller functions and to detect overheating events on the bulk medium or coupling strip. Cold spots can be locations selected as operating relatively colder than other locations on the bulk medium when the heating system is activated. Cold spot sensors can be used for general controller functions and to detect underheating on the bulk medium or coupling strip. Refreezing points can be locations selected as more likely to experience freezing or refreezing events faster than other locations on the bulk medium when the heating system is activated or after the heating system is deactivated. Refreezing point sensors can be used for general controller functions and to detect refreezing events or underheating on the bulk medium or coupling strip. Other points may be located in other areas of interest, such as the areas of interest listed earlier in this specification.

[0352] In some implementations, the layout of the coupling strips on the bulk medium can be optimized so that the area where the above points exist is a designated area selected for parameters such as ease of access for users of the heating system, ease of installation, or ease of visual observation.

[0353] In some implementations, at least two independent sets of ice sensors can be used to improve the reliability of critical controller functions by adding redundancy to their sensing subsystems. In some implementations, independence can be achieved by adding two identical ice sensors at each specified sensor location. In some implementations, independence can be achieved by adding two different ice sensors (e.g., from different manufacturers or of different sensor types) at each specified sensor location. In some implementations, independence can be achieved by adding two ice sensors at locations sufficiently far apart to reduce the likelihood of simultaneous sensor failure while being close enough to monitor equivalent parameters. In some implementations, independence can be achieved through any combination of these methods. In some implementations, the independent sensor sets can send information to a single monitoring subsystem, or to separate sets of monitoring subsystems each dedicated to their respective independent sensor sets, or all to at least two separate sets of monitoring subsystems.

[0354] In some implementations, the controller's sensing subsystem includes one or more capacitive sensors. These capacitive sensors can be used individually or in combination with other sensors, such as temperature sensors, to distinguish between ice and water. For example, a circuit board (e.g., a flexible printed circuit board (or flexible PCB)) including an array of one or more capacitive sensors can be arranged on the surface of a bulk medium to measure changes in capacitance readings on the surface, for example, due to the presence of ice or water. As another example, the capacitive sensors can be arranged beneath a covering layer of the bulk medium (e.g., a coating alternative film).

[0355] In some implementations, the temperature on the coupling strip 1900 can be derived from impedance measurements, which can be similarly measured as a function of time, for example, by comparing the impedance measurements with a database of reference plots of frequency responses at different temperatures. For instance, data can be collected on a test system to record the impedance frequency response as a function of ambient temperature. The controller can then use the recorded data to infer the coupling strip temperature from the impedance readings.

[0356] In some such implementations, the coupling strip 1900 includes one or more materials exhibiting significant and predictable impedance changes with temperature, thereby facilitating the assessment of the temperature of a target region of the bulk medium using impedance measurements. For example, the coupling strip 1900 may be constructed in part using dielectric materials or conductors whose dielectric constant or conductivity can predictably change with temperature, resulting in a localized change in impedance within the target region of the bulk medium. For example, the coupling strip 1900 may be constructed using one or more of the following: acrylic adhesives, silicone adhesives, ethylene-vinyl acetate adhesives, polysulfide sealants, polyurethane sealants, Mylar, PTFE, FEP, Kapton, and epoxy-based materials.

[0357] For example, to determine the current temperature of a particular coupling strip, a controller can measure the impedance value of that coupling strip and then compare the impedance value with a temperature value in a lookup table. As another example, the controller can perform an impedance measurement and then (e.g., based on a mathematical relationship between impedance and temperature) calculate the temperature from the measured impedance value. As a specific instance, acrylic adhesive materials can be used to construct the bottom dielectric layer of the strip that separates the coupling strip from the bulk medium.

[0358] Figure 41 This is a 3D plot of the dielectric constant of an example acrylic adhesive material. Figure 42 This is a plot of the dielectric constant of an exemplary acrylic adhesive material.

[0359] like Figure 41 As shown, the dielectric constant of the acrylic adhesive material ( The dielectric constant varies with temperature (°C). Specifically, the dielectric constant drives the characteristic impedance of a system comprising the coupling strip and the bulk dielectric. Therefore, as the temperature of the coupling strip changes, the dielectric constant changes accordingly. This, in turn, leads to a change in the system's impedance.

[0360] In some implementations, impedance can be measured as a function of time, and since impedance generally varies with temperature, the de-icing status can be determined based on impedance measurements using a detection scheme similar to that used for temperature measurement. Specifically, the time point for de-icing the bulk medium can be determined when the impedance plotted over a reference timescale is relatively flat (e.g., zero slope) for a predetermined period, followed by a period with a positive or negative slope. Figure 40 As shown in plot 4500, when the de-icing operation is in progress (from approximately 07:00 to 07:20), the impedance reading hovers around a fixed value (5.7Ω), and then increases when the de-icing operation is completed (starting from approximately 07:20).

[0361] electric

[0362] In some implementations, the controller includes control, sensing, and monitoring subsystems for measuring electrical parameters and performance. Such parameters include voltage, current, input, and output power at any output impedance at any stage of the heating system, including its power control system, wiring, cabling, connectors, and electrodes.

[0363] In some implementations, the controller uses and analyzes the collected electrical parameters to assess the health of the heating system and its components, control the amount of power directed to the target area of ​​the block medium, ensure that sufficient heating is being performed, notify the system user of any faults and errors, and log the collected data for further diagnostics from the system user or maintenance personnel.

[0364] In some implementations, the controller can verify that all measured electrical parameters are within the expected range in order to perform its control and monitoring functions.

[0365] In some implementations, output and input power at any stage of the power control system are measured simultaneously, allowing the controller to assess the power level and efficiency of that stage. For example, by monitoring power level and efficiency (input power divided by the power delivered to the heating element), faults in the system can be detected and de-icing failures can be reported. This can be used, for example, to infer that insufficient power delivered to the load will result in incomplete de-icing.

[0366] In some implementations, the voltage-to-current ratio at the input and output of any stage of the heating system is measured and utilized by the controller. As an example, in some stages of the heating system implementation, changes in downstream electrical components will cause changes in the voltage-to-current ratio of the upstream stage of the electrical system, and detecting these changes enables the detection of remote downstream faults and performance metrics.

[0367] Frequency domain analysis is commonly used to analyze cables and high-frequency systems, for example, by determining the amplitude and phase of the input impedance of a circuit over a frequency range. This information can be used to assess the health of a heating system and, in implementations where the system includes coupling strips (which act as transmission lines), to evaluate the characteristic impedance, propagation constant, termination, and length of the coupling strips.

[0368] For example, for a transmission line with a known characteristic impedance, the open-circuit termination impedance can be varied from 0 at a length that is an odd multiple of one-quarter of the wavelength of the traveling signal to Z0 at a length that is a multiple of half the wavelength.

[0369] The analysis can be performed from a single point, or, if both ends of the cable are accessible, a “2-port” measurement can be performed, which analyzes the transmission and reflection of signals from one port to the other.

[0370] Measurements in the frequency domain are most often performed using a network analyzer, which is a tool that transmits a series of frequencies at a high level, calculates impedance based on the voltage / current ratio, interpolates, and displays the data.

[0371] Tools also exist for verifying the presence of any changes in transmission line systems. In complex electrical systems where cables can travel long distances and are difficult to access, transmission line analysis is a useful tool for checking for cable breaks or other unwanted changes.

[0372] Impedance measurements can detect cuts and other direct damage to coupling strips and other cables in the heating system. Further details, such as whether the coupling strip or cable is completely or partially cut, can also be determined. An example of a detectable error is a change in length. For instance, if the coupling strip or cable is cut, it shortens (and its termination may change), and its input impedance changes according to the following formula:

[0373] .

[0374] Faults can also be detected when the termination deviates from the expected value, such as if a normally open-terminated coupling strip is short-circuited, or if a normally short-terminated coupling strip is cut or stripped into an open-terminated strip.

[0375] It is worth noting that the passive monitoring of the operating power control system can detect the impedance at the operating frequency. Therefore, the diagnostic functions described in the remainder of this document can be implemented during operation.

[0376] While using a network analyzer assumes that a sinusoidal signal is sent to the device being measured to obtain its frequency response, thus making it an active measurement method, passive monitoring involves monitoring signals (e.g., voltage and current) flowing through the device during its normal operation to calculate its impedance. Because network analyzers can extract information from operating signals and conditions, they cannot provide a wide range of information as wide as a full-scan frequency. However, network analyzers can still be used to monitor for failures. Furthermore, network analyzers can operate continuously, including while a heating system is running.

[0377] There are three main elements in the implementation of passive monitoring.

[0378] interface:

[0379] The interface between the power system and the monitoring system should be carefully designed. For example, it is important that excessive power (e.g., power designated for ice protection) does not enter the monitoring system.

[0380] division:

[0381] Another key element of the system is calculating the impedance (e.g., V / I) based on voltage and current. This requires both to be accurate and appropriately fast, as well as maintaining phase information.

[0382] Signal conversion

[0383] Once the impedance signal is calculated, for example using an analog-to-digital converter, it is typically converted into a form more suitable for monitoring the subsystem.

[0384] Passive monitoring is a useful tool for protecting the entire system, allowing for real-time fault detection and protecting electrical power systems from any damage that may be caused by the fault.

[0385] In some implementations, the controller can replace the operation of the network analyzer system by supplying power to the coupling strip. For example, the controller can intermittently switch the power supplied to the coupling strip while the network analyzer is connected to check for faults. After the network analyzer obtains measurement results, the power flow to the coupling strip can be restarted. The network analyzer can then be disconnected to avoid corruption from the power signal. In some implementations, the network analyzer can rotate between measurements on different coupling strips. For example, the controller or control system can alternately turn off the power flow to different coupling strips while obtaining network analyzer measurement results on the strip. Thus, adjacent coupling strips can still maintain some heat on the surface of the aircraft near the coupling strip undergoing network analyzer measurements.

[0386] In some implementations, the network analyzer can be configured to operate using a signal frequency range different from that of the power supply system. For example, a power signal can be supplied in the range of 100 to 450 MHz, while the network analyzer can be configured to use a test signal in the range of 1 to 10 MHz to measure the impedance of the coupling strip. A low-pass filter can be provided between the network analyzer's input / output and the power supply to prevent damage to the network analyzer from the power signal and to allow impedance measurements of the coupling strip without stopping the heating operation.

[0387] In some implementations, the controller additionally uses time-domain reflectometry (TDR) for its functionality. TDR is the study of transmission line reflections. TDR is commonly used to detect failures in very long or hard-to-reach cables. The key difference between TDR and the aforementioned methods is its focus on the time domain. This means that TDR can measure the travel time of a signal reaching the end of a cable or coupling strip and bouncing back to its point of entry. For example, TDR is an effective tool for measuring parameters such as transmission line or coupling strip length or characteristic impedance. Because TDR can derive parameters that are difficult to extract from frequency plots, it is an important complement to frequency domain analysis.

[0388] Figure 34 An example implementation of a TDR is depicted, demonstrating how a TDR can be used to detect, for example, open circuits, short circuits, and impedance mismatches on a coupling strip attached to an aluminum panel.

[0389] As a result, TDR allows for the characterization and localization of discontinuities, faults, or defects in transmission lines, cables, or coupling strips. For example, for cables of uniform material, the propagation speed of electrical signals can be measured. Using this propagation speed, the distance relative to the measurement point can be measured by the TDR, as well as any disturbances, faults, termination variations, or alterations, and plotted as localized changes in impedance.

[0390] TDR uses a very fast pulse generator that sends a signal to the system being measured. Key pulse parameters, including the time required for a low-to-high voltage transition, are tuned for each specific system under test and for each specific measurement target to capture the desired data. This pulse is then measured with an oscilloscope. Specialized instruments combining a pulse generator and a sampling oscilloscope, optimized for periodic measurements, can be used. However, specialized instruments are not always necessary. The time-domain representation can be reconstructed from the frequency domain. Using the inverse Fourier transform, the output of the network analyzer can be converted into an approximation of the expected time-domain behavior.

[0391] Because TDRs allow for the characterization and location of discontinuities in transmission lines, they can be used to detect short circuits, open circuits, wire stripping, and other transmission line damage in heating systems, such as in their cables and coupling strips.

[0392] exist Figure 35A The image shows a comparison of two transmission lines in our transmission line diagram, measured using a TDR. A connector is present on one line after 2 meters, which appears in the diagram as a large impedance change located in a narrow area. The same technique can be similarly used to detect deformation, short circuits, and stripping of transmission lines or coupling strips from the bulk medium. In some implementations, the controller performs automated analysis of the results. Using appropriate signal processing and advanced analytics techniques (e.g., leveraging machine learning, computer vision, deep learning, artificial intelligence, and other data-driven methods), real-time results can be compared to stored references to detect, characterize, and quantify changes, and the diagram can be interpreted to determine parameters including impedance, termination, and length.

[0393] It can be shown that components of a heating system (such as its cables and coupling strips) have temperature-dependent geometric and material properties in implementations that include these components. For example, the geometry of transmission lines and coupling strips may be affected by thermal expansion and contraction. It can be further shown that the conductivity, dielectric constant, and permeability of the materials incorporated in the construction of the coupling strip can vary with temperature. The foregoing sections describe how faults can be detected by measuring impedance changes at different points within the system. In addition to detecting changes in the physical structure of the coupling strip or bulk medium, the system's de-icing status can also be assessed. Impedance changes-temperature can be calculated empirically, simulated, or measured. In some implementations, the impedance of the coupling strip and its impedance change over time can be measured to infer its temperature, thus providing an additional method for the controller to perform its function.

[0394] Another useful metric is the rate of change of measured impedance. It can be shown that during a phase change, the material (in this case, ice melting into water) continues to absorb energy but does not change temperature (in this case, remaining at 0°C until completely melted). In some implementations, the controller can measure the impedance of the coupling strip and utilize this characteristic to aid in its functions, including determining whether de-icing is in progress or complete.

[0395] Detecting damage and alterations to bulk media.

[0396] In implementations where coupling strips are mounted on a bulk medium such that (e.g., by mounting the coupling strip on an aluminum skin such that the aluminum skin is one of the grounding layers of the resulting strip lines formed by the combination of the coupling strip and the aluminum skin) the bulk medium can be considered part of the transmission line geometry, these methods can be used to detect changes, alterations, and damage in the bulk medium even if the coupling strip itself remains unchanged. For structures with coupling strips that have sufficient coverage on the bulk medium (where these lines are routed back to an electrical system such as the heating system described herein), parts of the bulk structure can be analyzed and potential damage from centralized measurement points can be monitored.

[0397] In some implementations, changes to the structure of the bulk medium can be viewed as geometric changes to the transmission lines formed by coupling strips coupled to the bulk medium, and analyzed as these geometric changes. For example, indentations can alter the geometry of the bulk medium, thereby changing the characteristic impedance of the transmission lines in the region.

[0398] When installed on the skin of an aircraft, the system described herein can provide skin and structural damage detection capabilities. This damage detection can be performed autonomously via control and sensing circuitry embedded in the aircraft, or autonomously using dedicated diagnostics taken to a designated location within the aircraft by maintenance personnel. Currently, this type of damage is typically detected through visual inspection, a time-consuming and error-prone process. Furthermore, in-flight damage detection is limited to events large enough that maintenance personnel would notice them without the aid of any diagnostic system.

[0399] In the case of composite skin aircraft, transmission lines can be embedded in the composite layers of the skin material (e.g., taking advantage of lightning protection shielding and adding conductive lines in another layer to form embedded microstrips or strip lines), thereby allowing damage detection, including composite material peeling.

[0400] In some implementations, the system may include separate sensing lines arranged to detect faults in the coupling strip. For example, the coupling strip may be susceptible to a particular type of fault: stripping (where the coupling strip is at least partially not bonded to the bulk medium). In some such implementations, the sensing lines may be configured to be more sensitive to certain faults. In some implementations, the sensing lines may be included together with the carrier lines in the coupling strip 1900.

[0401] Figure 38A schematic diagram depicts an exemplary implementation of a coupling strip 3800 configured with a sensing line 3820 and a carrier line 3810. The carrier line 3810 is a conductive path within the coupling strip 3800 carrying current for heating a bulk medium, while the sensing line 3820 is a separate conductive path configured to sense faults in the overall carrier line 3810 or the coupling strip 3800. The sensing line 3810 can carry current (AC or DC) intermittently or continuously for sensing faults in the overall carrier line or the coupling strip. Under normal operating conditions (e.g., no fault), the current in the sensing line is typically less than the current in the carrier line. For example, the coupling strip 3800 can be coupled with the addition of the sensing line 3820... Figure 19 Corresponding to coupling strip 1900 in the image. Sensing line 3820 can be added to the coupling strip in the same layer as the carrier line (e.g., ...). Figure 19 In the conductive path 1904, or added in a layer separate from the carrier line 3910.

[0402] exist Figure 38 In the arrangement shown, sensing line 3820 can be referred to as a transmission line loop detection sensing line. The implementation shown facilitates the use of DC impedance measurements to detect faults such as open circuits (e.g., cuts in carrier line 3810) and short circuits (e.g., damage causing carrier line 3810 to short-circuit to the bulk medium or the shielding of the coupling strip).

[0403] As referenced above Figure 23 As described in layout B, the conductive layers within the coupling strip 3810 are arranged in a triple-overlapping configuration. The conductive layers in layout B comprise, for example, three segments arranged side-by-side in an S-shaped path from the input to the termination. Figure 38 In the example, an open circuit or short circuit can be detected based on DC impedance (i.e., by using appropriate circuitry to perform a DC connectivity test or a DC open circuit test).

[0404] Figure 39A A schematic diagram of another exemplary implementation of a coupling strip 3900A configured with a carrier line 3910 and a sensing line 3920 is depicted. Figure 39B A schematic diagram depicts yet another exemplary implementation of a coupling strip 3900B configured with carrier line 3910 and sensing line 3920. Figure 39A and Figure 39B In the implementation shown, the sensing line 3920 can be referred to as the end-terminated sensing line.

[0405] In any example, the sensing line 3920 is arranged closer to the carrier line 3910, that is, closer to the carrier line 3910 relative to the conductive shielding layer 3940. In other words, the spacing between the sensing line 3920 and the carrier line 3910 is closer than the spacing between the sensing line 3920 and the shielding layer 3940. In some implementations, the spacing between the heating carrier line 3910 and the bulk medium 3930 is further smaller than the spacing between the sensing line 3920 and the carrier line 3910.

[0406] exist Figure 39A In the example, when the coupling strip 3910 is properly attached and not stripped, the AC signal in the carrier line 3910 remains electrically coupled to the bulk medium 3930. In the event of stripping, i.e., when the carrier line 3910 separates from the bulk medium 3930, the coupling strip signal is decoupled from the bulk medium 3930 and instead coupled to the sensing line 3920.

[0407] A current sensor, configurable to detect changes in the flow of electricity in a wire or circuit, can be used by the system to determine that more current than should normally flow is passing through sensing line 3920, and thus detect a stripp. Specifically, the system can perform threshold-based stripp detection. For example, on a properly laminated line, the current measured on the sensing line will be relatively low. However, on a (partially) stripped line, the current will be higher than a threshold current value. The threshold can be selected to enable detection of a given stripp length (e.g., 10 cm) while still being high enough to avoid false positives during normal operation of the coupling strips 3900A or 3900B.

[0408] Additionally or alternatively, the system may use a two-port network analyzer sensor, wherein a first ground reference port is connected to the carrier line 3910 and a second ground reference port is connected to the sensing line 3920. This network analyzer sensor can be configured to quantify the coupling between the sensing line and the carrier line by measuring the S-parameters (e.g., S21 parameters) of the sensor's two-port network at one or more selected frequencies. Stripping can then be detected when the S21 parameter exceeds a predetermined threshold.

[0409] In some implementations, the heating system may include any of a variety of self-changing components that can be used to assist in the detection of system failures, including stripping. Specifically, the coupling strip 1900 may be configured to fail in a detectable failure configuration when in a particular failure mode. The coupling strip 1900 may be configured such that failure occurs early enough to be detected quickly and before, for example, triggering any undesirable failure consequences on the bulk medium 1902.

[0410] As an example, the dielectric separation between conductive layer 1904 and conductive shielding layer 1906 can be made of one or more predetermined materials such that when the dielectric separation begins to melt after its temperature exceeds a threshold temperature (e.g., when heat locally accumulates on the stripe of coupling strip 1900 on the stripe of coupling strip 1900 from bulk medium 1902 because the peeled portion of the coupling strip couples the heating signal to its own conductive shielding layer (rather than the bulk medium) and thus self-heats the unbonded portion of the coupling strip), the dielectric separation begins to change geometry and lose insulation. The altered (e.g., electrically short-circuited) dielectric separation between conductive layer 1904 and conductive shielding layer 1906 results in a drastic change in the performance and input impedance of the coupling strip, based on which any peeling can be easily detected, for example, by using a current sensor or impedance sensor. For example, a drastic change in impedance could be an increase or decrease of one or more orders of magnitude in the impedance of the coupling strip compared to the impedance of the coupling strip during normal (non-faulty) operation.

[0411] For example, in the case of de-icing the outer surface of an aircraft, since the heating system typically operates in the range of 50°C to 60°C, the threshold temperature can be set to a value greater than the upper limit of the normal range and much lower than a harmful temperature (e.g., fuel tank ignition) (e.g., 130°C). In this example, polysulfide-based materials are suitable examples of materials for constructing dielectric separations.

[0412] As another example, the conductive layer 1904 may be composed of one or more predetermined materials, such that the conductive layer 1904 loses its conductivity as the temperature rises, for example, by decreasing to an open state, thereby allowing direct detection of delamination. In this example, copper, aluminum, and alloys are suitable materials for constructing the conductive layer.

[0413] As another example, the bottom dielectric layer can be composed of one or more predetermined materials whose dielectric constant can change significantly with respect to temperature, thereby providing detectable impedance changes that can be used to indicate faults or to achieve accurate temperature measurements through impedance measurements. In this example, acrylic adhesives, silicone adhesives, ethylene-vinyl acetate adhesives, polysulfide sealants, polyurethane sealants, Mylar, PTFE, FEP, and Kapton are suitable materials for constructing the bottom layer.

[0414] In some implementations, the conductive layer 1904 can be configured to be less sensitive to certain aspects of the system compared to others. For example, the conductive layer 1904 can be configured in a way that keeps its impedance, cross-sectional area, or both relatively temperature-independent. In this way, any fault in the system (such as stripping that triggers a significant impedance change) becomes easily distinguishable from normal operating variations of the system.

[0415] Specifically, different construction materials, different bonding materials and associated bonding methods, different geometries (such as different cross-sectional dimensions), or different termination configurations can be considered to achieve the desired sensitivity of the conductive layer 1904 in these implementations. For example, water-based adhesives exhibit drastic impedance changes near 0°C, while alcohol-based adhesives such as ethylene-vinyl acetate (EVA) exhibit more consistent or stable impedance changes. Epoxy resins also exhibit relatively stable dielectric behavior.

[0416] Frequency domain analysis for detecting mechanical changes in bulk media

[0417] Changes in impedance can also be used to detect mechanical changes (e.g., dents or cracks) to aircraft skin or other bulk media. For example, changes in impedance are detectable after an impact on or outside the coupling strip. This is confirmed using an impact test setup. A 1.2 kg indenter is dropped onto the panel from a height of 2.8 m. This was chosen to create a 4 mm dent at a point 25 mm relative to the nearest fastener that attaches the aircraft skin to a structural element (e.g., a wing rib). The observed change is small enough not to cause system failure, but large enough to be detected.

[0418] Figure 35B The normalized real parts of the impedance immediately before and immediately after the impact are shown. "Near the front end," "Near the connector," and "Middle" indicate the effect on the coupling strip at those locations. "Between" and "Far" indicate the impact between two branches of the coupling strip and the impact far from the nearest coupling strip (~18cm). As shown, the impedance jump can be seen after the impact.

[0419] like Figure 35B As shown, a relatively small jump (~5%) in impedance can be observed after the impact. This is detectable for both impacts on and outside the coupling strip. Because the change in impedance is identifiable, this can be used to detect impacts even for impacts far from the coupling strip, including impacts occurring between lines. Since the lines will cover most of the aircraft's surface for our system, these lines can be used to monitor the structure and detect mechanical changes (e.g., dents or cracks).

[0420] Frequency domain analysis for cable fault detection

[0421] In some implementations, frequency domain analysis plots can be used to detect any cable faults that may be present in the heating system 100 (e.g., stripping of the coupling strip 1900); and can also be used to detect mechanical changes in the aircraft skin or other bulk media (e.g., dents or cracks). In particular, advanced graphical analysis techniques, including plotting transformation techniques (e.g., Fourier transform) and machine learning techniques (e.g., neural networks), can be used to extract features or characteristics that can detect the presence of cable faults or mechanical changes in the bulk media from frequency response plots, data derived from frequency response plots, or both. Generally, different features or characteristics can indicate different types of cable faults and mechanical changes in the bulk media.

[0422] For example, these features or characteristics may include minimum or maximum resistance or θ values, and the associated frequency values ​​at which these minimum or maximum values ​​are located. As another example, these features or characteristics may include resonant peak mode information, such as the dominant mode of the resonant peaks, the distance between peaks, and the consistency between peak-to-peak frequency intervals.

[0423] Figure 43 Plots depicting the frequency response of healthy coupling strips (e.g., non-faulty coupling strips) and faulty coupling strips mounted on bulk media are shown. In this example, as a specific type of cable fault, stripping can be detected based on whether the values ​​of resonant peaks (e.g., resonant peak 4310) within a given frequency range are monotonically decreasing or increasing. As shown in plot 4300, for a healthy coupling strip, the resonant peak decreases monotonically. However, as shown in plot 4350, for an unhealthy (e.g., stripped) coupling strip, the resonant peak may first decrease, then increase, and then decrease again.

[0424] In some implementations, faults in cables (e.g., coupling strips), such as short circuits, open circuits, or stripping, can be detected by comparing the measured impedance-frequency of a particular cable with data indicating an expected pattern of impedance-frequency in a non-faulty (e.g., healthy) cable. For example, a spectrum analyzer or TDR device can be used to measure the impedance-frequency or time-domain pattern of a particular cable. For a similar, fault-free cable (e.g., as shown in plot 4350), the measured impedance-frequency or time-domain pattern can be compared with an expected impedance relative to frequency or time-domain pattern. In a frequency domain example, a change in the characteristic or properties of the resonant peak mode of the measured impedance-frequency pattern compared to the expected impedance-frequency pattern can be used to identify one or more faults in the cable.

[0425] TDR for detecting mechanical changes in bulk media

[0426] Since dents and other mechanical variations in bulk media are localized deformations of the bulk medium, they can cause localized changes in the characteristic impedance of transmission lines mounted on the bulk medium. Therefore, TDRs are well-suited for detecting and locating mechanical variations in bulk media.

[0427] Figure 36 Examples of TDR (Transmission Reflection) on two different coupling strip designs are shown. The red line represents the dented test panel, while the blue line represents the baseline panel. Using TDR, it can be seen that along the coupling strip with the dent, there is a sharp change in impedance, manifested as fluctuations around its usual value for the undented panel. This information allows for further localization of the dent to a specific area of ​​the cable. Therefore, the location of damage to the underlying structure can be identified. Since the average characteristic impedance is roughly the same along the length of the coupling strip, this data can be challenging for detection using only the frequency response. However, TDR makes it possible to see local discontinuities.

[0428] In one heating system embodiment, TDR measurements of the coupled strips covering the bulk medium can be combined with analysis of the data obtained (e.g., using the advanced methods previously listed) to create a map of the skin and structural condition and health of the bulk medium. This can be used as a maintenance and service diagnostic tool, or as a real-time monitoring tool.

[0429] In implementations of electrical de-icing systems that use coupling strips to heat bulk media, multiple coupling strips are powered from the same high-frequency source. This implementation may include additional wiring so that the AC power supply is not physically close to the coupling strips in question. In these implementations, fault detection and de-icing assessment as described above remain feasible. In fact, a single monitoring system at the AC source is capable of monitoring the performance of all attached coupling strips. However, in another implementation, additional monitors can be placed at the inputs of each coupling strip. Each coupling strip can be viewed as a parallel element, with the additional wiring acting as a series element in the network. This network will still be defined by the geometric and material parameters of its construction.

[0430] In some implementations, multiple AC sources can be combined to feed power to one or more coupling strips as described above. Similarly, this would allow a single controller subsystem to detect the probability of a fault in one or more AC sources and one or more coupling strips. However, it is also possible to have separate monitors for each AC source, which would help isolate the source of the fault to a single system component. In this implementation, redundant AC sources could be installed, allowing the fault detection system to potentially keep redundant components online to compensate for the fault while still performing de-icing.

[0431] Some implementations of an electrical de-icing system may include a distributed or inline circuit between the AC source and the coupling strips. This circuit can be passive (containing only inductors, capacitors, resistors, and transformers). Alternatively, it can be active (including transistors, logic gates, or other components, such as in the case of an active IAN). In an active implementation, the circuit can be used for fault detection and de-icing assessment. In implementations feeding multiple coupling strips from a single or combined AC source, the distributed active circuit can isolate faults to individual coupling strip elements by deploying individual monitors to each coupling strip element. Furthermore, if additional redundant coupling strip elements are installed, the distributed active circuit can route power to other coupling strips to mitigate faults on individual coupling strips and complete de-icing. This distributed circuit can communicate with the AC source or any “upstream” circuit via wiring or known wireless communication protocols or by manipulating the system’s voltage, current, or impedance. For example, in one implementation, the distributed circuit can use an electrical or electromechanical switch to disconnect any coupling strip whose impedance is outside the normal range. This disconnection can then be detected at the AC source by a monitoring system, while also ensuring that the fault-coupled strip is not energized, thus preventing further potential damage to the system. In another implementation, by coordinating other sensors (e.g., temperature sensors, ice sensors) with this distributed circuitry, power can be directed directly to areas of greater ice accumulation.

[0432] In implementations where multiple coupling strips are attached to the same bulk medium, faults in nearby coupling strips can be detected by transmitting a signal to a single coupling strip. All coupling strips attached to the same bulk structure may have some degree of electromagnetic coupling. Induced signals can be picked up by placing a transmitter (such as an AC power supply, network analyzer, TDR, etc.) on one coupling strip and a receiver (such as an oscilloscope) on a separate coupling strip. This can be used to verify that the coupling is within the expected range. If the coupling factor is outside the expected range, this may indicate a fault. For example, in one possible implementation, poor electrical connection between a coupling strip and the bulk structure may lead to increased coupling with other coupling strips. This will also result in insufficient heating for de-icing purposes. This error can be detected by monitoring the induced signals on other coupling strips.

[0433] In some implementations, similar to the above, TDR plots can be used, for example, to assist in the detection of stripping of coupling strips by analyzing certain features depicted or otherwise extracted from TDR plots using graphical analysis techniques.

[0434] In addition to detecting defects in coupling strips or dents in bulk media, TDR or frequency domain analysis can be used to detect the presence of various contaminants such as water or ice on bulk media and to determine the types of contaminants present on the bulk media, using techniques similar to those described above.

[0435] Note that, as used herein, the term "electrical connection" includes the connection of components to each other via an object having any electrical function, as opposed to a "direct connection" where two electrical components (e.g., connected directly to each other via wires or circuit traces without any further intermediary components such as resistors, capacitors, inductors, etc.) are directly coupled to each other. Furthermore, references to a first component electrically connected to a specific terminal of a second component are not intended to include electrical paths through the second component itself. For example, a capacitor electrically connected to the gate terminal of a transistor may include cases where the electrical connection passes through other objects or components having an electrical function, but does not include cases where the electrical connection passes through another terminal (e.g., source / drain) of the transistor itself to reach the transistor's gate.

Claims

1. A system for heating the exterior of an aircraft, the system comprising: A series of individual heating elements are arranged on the skin of the aircraft; The sensor is located on the skin at a position corresponding to a region of relatively low temperature within the heating pattern generated by the heating element; as well as A control system, connected to the heating element and the sensor, is configured to control the power supplied to the heating element in response to an output from the sensor. The relatively low temperature region is designed with a heating mode generated by the heating element, such that the heating mode produces a locally lower skin temperature in that region.

2. The system according to claim 1, wherein, The heating element is a coupling strip, which includes a multi-layered structure extending along the surface of the aircraft skin. The multi-layered structure, in conjunction with the aircraft skin, forms an electrical transmission line. The multi-layered structure includes: The first dielectric layer on the aircraft skin The conductive layer on the first dielectric layer, The second dielectric layer on the conductive layer, and The conductive shielding layer on the second dielectric layer.

3. The system according to any one of claims 1 and 2, wherein, The location includes structural features on the aircraft skin that are arranged to maintain a lower local temperature at the location relative to the majority of the temperature of the aircraft skin when the heating element is active.

4. The system according to claim 3, wherein, The structural features include the arrangement of the heating element to provide less heat to the location relative to most of the aircraft skin.

5. The system according to any one of claims 1 and 2, wherein, The heating elements are arranged in a geometry that provides a larger local element spacing.

6. The system according to claim 5, wherein, The control system is configured to, at a higher thermal mass location, cause one or more heating elements to operate at a lower power density compared to the power density at which other heating elements operate, and / or The control system is configured to locally adjust the output power to generate the heating mode.

7. The system according to any one of claims 1 and 2, wherein, The sensor is a temperature sensor or an ice sensor.

8. The system according to any one of claims 1 and 2, wherein, The location is visible from the aircraft's window.

9. The system according to any one of claims 1 and 2, wherein, The control system is configured as follows: The characteristics of the aircraft skin at the location are detected based on the output from the sensor; Compare the value of the stated characteristic with a reference characteristic; as well as In response to a value determined to be of the characteristic indicating a freeze at the location, an indication of a freeze condition is triggered.

10. The system according to any one of claims 1 and 2, further comprising a second sensor located at a second position on the skin of the aircraft corresponding to a region of relatively high temperature within the heating pattern generated by the heating element. in, The control system is connected to the second sensor, and The control system is configured as follows: The temperature of the aircraft skin at the second location is detected based on the output from the second sensor; Compare the temperature with a reference temperature at the location; and An indication to trigger an over-temperature condition is given in response to the determination that the temperature is greater than the reference temperature.

11. The system according to any one of claims 1 and 2, wherein, The control system is configured as follows: The characteristics of the aircraft skin at the location are detected based on the output from the sensor; Compare the value of the stated characteristic with a reference characteristic; as well as In response to a value determined to indicate freezing at the location, power is applied to the heating element.

12. The system according to any one of claims 1 and 2, further comprising a second sensor located at a second position on the skin of the aircraft corresponding to a region of relatively high temperature within the heating pattern generated by the heating element. in, The control system is connected to the second sensor, and The control system is configured as follows: The temperature of the aircraft skin at the second location is detected based on the output from the second sensor; Compare the temperature with a reference temperature at the location; and In response to determining that the temperature is greater than the reference temperature, the power applied to the heating element is reduced.

13. The system according to claim 2, wherein, The control system includes an impedance monitoring subsystem connected to the coupling strip, the impedance monitoring subsystem being configured to: Monitor the input impedance of the heating element; as well as The fault in the heating element is detected based on the input impedance.

14. The system according to claim 13, wherein, Detecting faults in the heating element includes: Obtain the first impedance-frequency mode of the heating element; and The fault is detected by comparing the first impedance-frequency pattern with a second impedance-frequency pattern used to indicate the expected impedance in the absence of any fault.

15. The system according to claim 13, wherein, The impedance monitoring subsystem includes a passive system configured to detect the impedance of the heating element based on the electrical characteristics of the heating element in response to a power signal applied to the heating element.

16. The system according to claim 13, wherein, The impedance monitoring subsystem includes an active system configured to transmit a test signal to the heating element and, in response to the test signal, detect the impedance of the heating element based on its electrical characteristics.

17. The system according to claim 2, wherein, The control system includes an impedance monitoring subsystem connected to the coupling strip, the impedance monitoring subsystem being configured to: Monitor the input impedance of the heating element; as well as The mechanical changes in the aircraft skin are detected based on the input impedance.

18. The system according to claim 2, wherein, The control system includes a time-domain reflectometry (TDR) monitoring subsystem connected to the coupling strip, and the TDR monitoring subsystem is configured as follows: Monitor the time-domain electrical impulse response of the heating element; and Faults in the heating element are detected based on the time-domain electrical impulse response.

19. The system according to claim 18, wherein, Detecting faults in the heating element includes: Obtain the first time-domain reflectometry mode, i.e., the first TDR mode, of the heating element; and The fault is detected by comparing a first TDR mode with a second TDR mode, which is used to indicate the heating element in the absence of any faults.

20. The system according to claim 2, wherein, The control system includes a time-domain reflectometry (TDR) monitoring subsystem connected to the coupling strip, and the TDR monitoring subsystem is configured as follows: Monitor the time-domain electrical impulse response of the heating element; and Mechanical changes in the aircraft skin are detected based on the time-domain electrical impulse response.

21. A system for heating the exterior of a bulk conductor, the system comprising: A series of individual heating elements are arranged on the skin of the bulk conductor; The sensor is located on the skin at a position corresponding to a region of relatively low temperature within the heating pattern generated by the heating element; as well as A control system, connected to the heating element and the sensor, is configured to control the power supplied to the heating element in response to an output from the sensor. The relatively low temperature region is designed with a heating mode generated by the heating element, such that the heating mode produces a locally lower skin temperature in that region.

22. The system according to claim 21, wherein, The heating element is a coupling strip, which includes a multi-layer structure extending along the surface of the bulk conductor skin. The multi-layer structure, in conjunction with the bulk conductor skin, forms an electrical transmission line. The multi-layer structure includes: The first dielectric layer on the bulk conductor skin The conductive layer on the first dielectric layer, The second dielectric layer on the conductive layer, and The conductive shielding layer on the second dielectric layer.

23. The system according to any one of claims 21 and 22, wherein, The location includes structural features on the bulk conductor skin, which are arranged to maintain a lower local temperature at the location relative to the majority temperature of the bulk conductor skin when the heating element is active.

24. The system according to claim 23, wherein, The structural features include the arrangement of the heating element to provide less heat to the location relative to most of the bulk conductor skin.

25. The system according to any one of claims 21 and 22, wherein, The heating elements are arranged in a geometry that provides a larger local element spacing.

26. The system according to claim 25, wherein, The control system is configured to, at a higher thermal mass location, cause one or more heating elements to operate at a lower power density compared to the power density at which other heating elements operate, and / or The control system is configured to locally adjust the output power to generate the heating mode.

27. The system according to any one of claims 21 and 22, wherein, The sensor is a temperature sensor or an ice sensor.

28. The system according to any one of claims 21 and 22, wherein, The location is visible from the window of the bulk conductor.

29. The system according to any one of claims 21 and 22, wherein, The control system is configured as follows: The characteristics of the bulk conductor skin at the location are detected based on the output from the sensor; Compare the value of the stated characteristic with a reference characteristic; as well as In response to a value determined to be of the characteristic indicating a freeze at the location, an indication of a freeze condition is triggered.

30. The system according to any one of claims 21 and 22, further comprising a second sensor located at a second position on the skin of the bulk conductor corresponding to a region of relatively high temperature within the heating mode generated by the heating element. in, The control system is connected to the second sensor, and The control system is configured as follows: The temperature of the bulk conductor skin at the second location is detected based on the output from the second sensor; Compare the temperature with a reference temperature at the location; and An indication to trigger an over-temperature condition is given in response to the determination that the temperature is greater than the reference temperature.

31. The system according to any one of claims 21 and 22, wherein, The control system is configured as follows: The characteristics of the bulk conductor skin at the location are detected based on the output from the sensor; Compare the value of the stated characteristic with a reference characteristic; as well as In response to a value determined to indicate freezing at the location, power is applied to the heating element.

32. The system according to any one of claims 21 and 22, further comprising a second sensor located at a second position on the skin of the bulk conductor corresponding to a region of relatively high temperature within the heating mode generated by the heating element. in, The control system is connected to the second sensor, and The control system is configured as follows: The temperature of the bulk conductor skin at the second location is detected based on the output from the second sensor; Compare the temperature with a reference temperature at the location; and In response to determining that the temperature is greater than the reference temperature, the power applied to the heating element is reduced.

33. The system according to claim 22, wherein, The control system includes an impedance monitoring subsystem connected to the coupling strip, the impedance monitoring subsystem being configured to: Monitor the input impedance of the heating element; as well as The fault in the heating element is detected based on the input impedance.

34. The system according to claim 32, wherein, Detecting faults in the heating element includes: Obtain the first impedance-frequency mode of the heating element; and The fault is detected by comparing the first impedance-frequency pattern with a second impedance-frequency pattern used to indicate the expected impedance in the absence of any fault.

35. The system according to claim 22, wherein, The control system includes an impedance monitoring subsystem connected to the coupling strip, the impedance monitoring subsystem being configured to: Monitor the input impedance of the heating element; as well as The mechanical changes of the skin of the bulk conductor are detected based on the input impedance.

36. The system according to claim 22, wherein, The control system includes a time-domain reflectometry (TDR) monitoring subsystem connected to the coupling strip, and the TDR monitoring subsystem is configured as follows: Monitor the time-domain electrical impulse response of the heating element; and Faults in the heating element are detected based on the time-domain electrical impulse response.

37. The system according to claim 36, wherein, Detecting faults in the heating element includes: Obtain the first time-domain reflectometry mode, i.e., the first TDR mode, of the heating element; and The fault is detected by comparing the first TDR mode with a second TDR mode, which is used to indicate the expected TDR mode of the heating element in the absence of any faults.

38. The system according to claim 22, wherein, The control system includes a time-domain reflectometry (TDR) monitoring subsystem connected to the coupling strip, and the TDR monitoring subsystem is configured as follows: Monitor the time-domain electrical impulse response of the heating element; and Mechanical changes in the skin of the bulk conductor are detected based on the time-domain electrical impulse response.

39. The system according to claim 2 or 22, wherein, The conductive layer of at least one of the coupling strips includes a sensing line and a carrier line, the sensing line being arranged within the coupling strip to sense faults in the carrier line or the coupling strip.

40. The system according to claim 39, wherein, The first end of the sensing line is electrically connected to the carrier line, and the second end of the sensing line is electrically connected to the connectivity test terminal.

41. The system according to claim 39, wherein, The first end of the sensing line is electrically connected to the conductive shielding layer, and the second end of the sensing line is electrically connected to an AC voltage source.

42. The system according to claim 39, wherein, The sensing line includes one or more capacitors arranged to allow temperature measurement based on changes in the impedance of the sensing line.

43. The system according to claim 2 or 22, wherein, The coupling strip includes one or more self-changing components configured to fail in a predetermined manner to indicate a fault in the coupling strip.

44. The system according to any one of claims 1 and 21, wherein, The control system is configured to detect the status of the de-icing operation by: The temperature indicated by the sensor is measured over a period of time; In response to the determination that the temperature remains constant at approximately zero degrees Celsius for a period of time and then begins to rise, the de-icing is determined to be complete.

45. The system according to any one of claims 1 and 21, wherein, The control system is configured to measure the impedance frequency response of the coupling strip and estimate the temperature of the coupling strip based on the measured impedance frequency response.

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