Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F3/00—Cores, Yokes, or armatures
  • H01F3/10—Composite arrangements of magnetic circuits
  • H01F3/14—Constrictions; Gaps, e.g. air-gaps
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F27/00—Details of transformers or inductances, in general
  • H01F27/24—Magnetic cores
  • H01F27/255—Magnetic cores made from particles
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
  • H01F38/14—Inductive couplings
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
  • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
  • H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
  • H01F38/02—Adaptations of transformers or inductances for specific applications or functions for non-linear operation
  • H01F38/023—Adaptations of transformers or inductances for specific applications or functions for non-linear operation of inductances

Definitions

• the invention relates to a system for contactless power transmission from a primary conductor to a secondary coil.
• a system for the contactless transmission of energy from a primary conductor to a secondary coil can be implemented by means of an inductive coupling, in particular a transformer, for example.
• the invention is therefore based on the object of further developing a system, wherein
• the object is achieved in the system according to the features specified in claim 1.
• Important features of the invention in the system for contactless energy transmission from a primary conductor to a secondary coil, which has a secondary winding and a coil core, in particular wherein the secondary coil is arranged on a mobile part that is movably arranged relative to the primary conductor, in particular on the side of the mobile part that faces the primary conductor, are that the coil core has a constriction, in particular a constriction point, in particular wherein the coil core has a higher flux density in the area of the constriction than in an area of the coil core adjoining the constriction and/or wherein the coil core has a smaller wall thickness in the area of the constriction than in an area of the coil core adjacent to the constriction.
• the advantage here is that the constriction causes a current limitation. This is because the narrowing area already enters saturation at lower current intensities, and thus at a weaker magnetic field, and thus causes a corresponding change in the inductance of the secondary coil. If the coupling is preferably weak and the secondary coil is used in a resonant circuit, the transmitted power is reduced considerably, so that the current is prevented from increasing further, even if the resonant circuit short-circuits on the secondary side.
• the coil core in particular a ferrite core, is made of ferrite.
• the advantage here is that, despite the weak inductive coupling, as much of the magnetic field generated by the primary conductor as possible is captured in the coil core and/or that as many field lines generated by the primary conductor as possible are captured in the coil core.
• the advantage here is that with increasing current in the primary conductor and/or in the secondary winding and thus increasing magnetic field, saturation in the area of the constriction can be reached more quickly and the inductance can be reduced early on, so that a further increase in the secondary-side current can be prevented.
• the constriction is arranged in the area of the winding and/or in the area around which the winding is wound. The advantage here is that as much field as possible or as many field lines as possible generated by the primary conductor are forced to flow through the constriction. Thus, with increasing current, saturation can be reached quickly and safely.
• the constriction is surrounded and/or wrapped by the winding.
• the advantage here is that as much field as possible or as many field lines as possible generated by the primary conductor are forced to flow through the constriction. Thus, with increasing current, saturation can be reached quickly and safely.
• the constriction borders on the area of the winding and/or on the area wrapped by the winding.
• the constriction is not surrounded and/or wrapped by the winding.
• the advantage here is that the constriction is arranged outside of the wrapped area and thus the winding, in particular the winding wire, is prevented from slipping into the constriction, in particular during winding.
• the coil core is U-shaped, in particular with the primary conductor being arranged within the spatial area surrounded by the coil core.
• the advantage here is that the inductive coupling is as strong as possible, although the primary conductor is routed as a long line cable in the system and thus only generates a weak magnetic field.
• the winding is a flat winding arranged in one plane.
• the perpendicular projection of the constriction is in this plane comprised by the winding and/or comprised by the perpendicular projection of the winding into the plane.
• the advantage here is that the constriction is arranged in the area of the winding and thus many field lines are forced through the area of the constriction.
• the coil core is E-shaped, in particular with the secondary winding being wound around a middle leg of the E-shaped coil core, in particular as a flat winding, with the secondary winding being spaced apart from the primary conductor, in particular with the primary conductor being laid as an elongated closed loop in the system is laid, in particular with a section of the primary conductor acting as the outgoing conductor and a return conductor arranged parallel to the outgoing conductor being formed by a further area of the primary conductor, in particular with the yoke of the E-shaped coil core having a central limb and two outer limbs, with all limbs being the plane receiving the forward conductor and the return conductor, in particular wherein the perpendicular projection of the secondary winding wound around the middle leg of the E-shaped ferrite core into this plane comprises part of the forward conductor and part of the return conductor and/or includes a portion of the perpendicular projection of the forward conductor in that plane and a portion of the perpendicular projection of
• the secondary coil can be made very compact and the primary conductor system can be used magnetically twice as a forward conductor and a parallel return conductor, so to speak.
• the constriction has an elongated indentation and/or groove on one or both sides of the coil core, in particular the indentation or groove extending perpendicularly to the magnetic flux and/or to the magnetic flux density, in particular over the entire width of the coil core.
• the constriction is implemented as one or more recesses running through the coil core and/or the constriction has one or more recesses running through the coil core, in particular with the recesses being spaced apart from one another and/or being arranged in a straight row one behind the other .
• the advantage here is that the constriction affects the material provided for the magnetic field lines and is easy to produce.
• the distance between two recesses that are closest to each other decreases monotonically with increasing distance from an outer edge of the coil core, in particular in such a way that recesses that are arranged centrally in the coil core, in particular the yoke, are arranged next to one another closer to one another than those arranged further outside Recesses, in particular the outer edge is the outer edge arranged in that section plane whose normal is aligned parallel to the passage direction of the recesses.
• the constriction has an intermediate part arranged in a continuous air gap of the coil core, in particular the intermediate part having a smaller wall thickness than the region of the coil core adjoining the intermediate part. in particular wherein the intermediate part is made of ferrite.
• the shape of the intermediate part can be either cuboid or cylindrical. With a cuboid design, there are lower losses in normal operation than with the cylindrical design, which, however, can be thermally insulated better from the rest of the coil core with less effort than with the square design, since there is only a line contact with the rest of the coil core instead of a flat contact.
• the coil core and/or the intermediate part is coated with a layer at least in the surface areas on which the coil core rests on the intermediate part, the specific thermal conductivity of the material of the layer being lower than the specific thermal conductivity of the material of the coil core.
• At least one element is arranged between the coil core and the intermediate part, with the specific thermal conductivity of the material of the element being lower than the specific thermal conductivity of the material of the coil core, in particular with the element being a film or another part, such as a small plate .
• the intermediate part is designed as a cylinder and the air gap of the coil core is delimited by flat surfaces of the coil core, in particular so that there is only linear contact between the coil core and the intermediate part or element.
• the advantage here is that there is only a line contact and the thermal insulation of the intermediate part can therefore be implemented simply and cost-effectively.
• the secondary winding has such a capacitance connected in series or in parallel that the resonant frequency of the resonant circuit formed in this way, in particular the oscillating circuit, is the same as the frequency of the alternating current impressed on the primary conductor by a power source, in particular a feed device of the system.
• the advantage here is that a high level of efficiency can be achieved despite weak inductive coupling and/or inductive coupling that fluctuates depending on the movement of the mobile part.
• FIG. 1 shows a schematic sketch of a non-contact energy transmission system with a serial resonant circuit.
• FIG. 2 shows a schematic sketch of a non-contact energy transmission system with a parallel resonant circuit.
• FIG. 3 shows a secondary winding 33 with a ferrite core 31 which has a recess 32, in particular a constriction.
• the constriction 32 is designed as an elongated depression on both sides, in particular a groove.
• the constriction 32 is formed by a cuboid intermediate part 62 which is arranged in a continuous gap of the ferrite core 61.
• the constriction 72 is arranged, in particular, at the inner end of a leg of a U-shaped ferrite core 71 on which a secondary winding is wound.
• FIG. 8 shows a system for contactless energy transmission with an E-shaped ferrite core 83 wound with a secondary winding 84, with the constriction 82 being arranged on the outer side of the ferrite core 83 or with the constriction 85 being arranged on the inner side of the ferrite core 83 is.
• the system for contactless energy transmission has a primary conductor 1, which is laid elongated on the floor in a facility, with a mobile part having a secondary winding on its underside, which is inductively coupled to the primary conductor 1.
• This inductive coupling 2 is weak, for example.
• a capacitance C_k is connected in series to the secondary winding, which is dimensioned in such a way that the resonant frequency of the resonant circuit formed by the secondary winding and the capacitance C_k, in particular the oscillating circuit, is equal to the frequency of an alternating current impressed on the primary conductor 1 by a power source.
• a load R_L in particular a consumer, can be supplied from the resonant circuit.
• the load R_L has, for example, a rectifier and an inverter supplied from it, which feeds a drive motor of the handset. Additionally or alternatively, the load R_L has an energy store that can be loaded from the connection of the rectifier on the DC voltage side.
• the primary conductor 1 is laid along a rail along which a handset with a secondary winding moves.
• the secondary winding is in turn coupled inductively to the primary conductor 1 .
• FIG. 1 shows the inductive coupling 2 with its leakage inductance L_s on the secondary side as a schematic electrical circuit diagram.
• the primary conductor can be designed as a winding, with the mobile part being inductively coupled to this winding with its secondary winding.
• a secondary winding connected in parallel with the secondary winding can be used instead of the capacitance C_k connected in series. This means that lower voltages but higher currents can be achieved.
• the secondary winding 33 is wound around a yoke of a U-shaped ferrite core 31, the yoke being connected to two legs which are spaced apart from one another and are in particular aligned parallel to one another.
• a constriction 32 of the ferrite core 31 In the area of the yoke of the ferrite core 31 around which the secondary winding 33 is wound, there is a constriction 32 of the ferrite core 31 . If the current magnitude of the alternating current impressed on the primary conductor 1 is constant on the primary side, current limitation can be achieved.
• the current in the resonant circuit initially increases, but the ferrite material then becomes saturated in the area of the constriction 32, as a result of which the inductance changes and the resonant circuit is detuned. Due to this automatic limitation, the current only reaches an associated maximum value.
• the wall thickness of the ferrite core 31, in particular of the yoke of the ferrite core 31, is reduced in the area of the constriction 32.
• the constriction 32 on the ferrite core 31 is shown in an oblique view in FIG and/or extend.
• the indentations are preferably designed in accordance with a rectangular groove.
• recesses 52 running through the ferrite core can also be used instead of the recesses, the recesses 52 being spaced apart from one another and preferably being arranged in a straight line one behind the other with a respective spacing.
• the distance between two respectively next-neighboring recesses 52 decreases monotonically with increasing distance from an outer edge, in particular in the section shown in FIG.
• the recesses 52 arranged centrally in the yoke are arranged closer to one another than the recesses 52 arranged further to the outside.
• the outer edge always means the outer edge arranged in the sectional plane, the normal of which is aligned parallel to the passage direction of the recesses 52 .
• constriction can also be implemented by inserting an intermediate part 62 into a gap in the ferrite core 61, as shown in FIG.
• the wall thickness of the intermediate part 62 is less than the rest of the ferrite core 61.
• the intermediate part 62 is also made of ferrite.
• the intermediate part 62 made of ferrite material is preferably additionally coated on its surface with a layer whose specific thermal conductivity is lower than the specific thermal conductivity of the ferrite material.
• a high temperature can thus be achieved in the intermediate part 62, while the ferrite core 62 adjoining the intermediate part 62 is thermally stressed as little as possible.
• the temperature reaches the Curie temperature, the inductance of the secondary winding drops sharply, and the detuning of the resonant circuit becomes very large, and the secondary-side inductance becomes very small. In this way, current rise is limited since less current is transferred through the inductive coupling.
• the layer is advantageously arranged at least in those surface areas of the intermediate part 62 which are in contact with the ferrite core 61 .
• the constriction 72 is advantageously located within the area where the secondary winding 73 is wound.
• the left leg of the ferrite core 71 is provided with a secondary winding 73, within which the constriction 72 is arranged.
• the constriction is arranged outside the area wound with the secondary winding 73, in particular directly connected to the end of the secondary winding 73.
• an E-shaped ferrite core in particular a coil core, can also be used in a system according to the invention.
• the primary conductor is laid in the system as an elongated, closed loop, with a section of the primary conductor acting as a forward conductor and a return conductor 81 arranged parallel to the forward conductor 80 being formed by a further region of the primary conductor.
• the yoke of the E-shaped ferrite core 83 has a central limb and two outer limbs, with all limbs protruding toward the plane receiving the forward conductor 80 and the return conductor 81 .
• the in-plane vertical projection of the secondary winding wound around the center leg of the E-shaped ferrite core 83 includes part of the forward conductor 80 and part of the return conductor 81, specifically, it includes part of the in-plane perpendicular projection of the outgoing conductor 80 and part of the perpendicular projection of the return conductor 81 in the plane.
• the coil formed from the ferrite core 83 with the secondary winding 84 is always at a distance from the plane, ie in particular from the plane receiving the forward conductor 80 and the return conductor.
• the constriction 82 is arranged either on the side of the ferrite core 83 facing the secondary winding 84 or on the side of the ferrite core facing away from the secondary winding 84 .
• the constriction 85 is designed as an elongated groove, similar to FIG. The same applies to the constriction 82.
• constriction 85 and/or 82 can be embodied as a series of recesses 52 passing through the ferrite core 83, similar to FIG. 5, or as an intermediate part coated in particular with a layer, similar to FIG.
• the constriction 82 and 7 or the constriction 85 is located either in the region of the coil 84 or at the inner or outer end region of the coil 84.
• the winding 84 is designed as a ring winding and the middle leg of the E-shaped ferrite core 83 around, in particular as a single-layer flat winding.
• the ferrite core is coated with a layer at least on those surface areas on which the intermediate part 62 rests on the ferrite core 61 .
• the specific thermal conductivity of the material of the layer is smaller than the specific thermal conductivity of the ferrite material.
• elements in particular foils or parts such as small plates, can also be arranged between the intermediate part 62 and the ferrite core 61 .
• the wall thickness of the element is chosen to be as small as possible, but the heat transfer resistance from the element to the ferrite core 61 must be sufficiently high.
• a coil core made of a different ferromagnetic material is used instead of the aforementioned respective ferrite core.
• the highest possible specific magnetic permeability is advantageous in order to make the system compact.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Composite Materials (AREA)
• Computer Networks & Wireless Communication (AREA)
• Coils Of Transformers For General Uses (AREA)
• Coils Or Transformers For Communication (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

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ID=83049836

Family Applications (1)

Country Status (3)

Citations (8)

• 2022
  • 2022-07-27 DE DE102022002735.6A patent/DE102022002735A1/de active Pending
  • 2022-07-27 WO PCT/EP2022/071126 patent/WO2023041232A1/de active Application Filing
  • 2022-07-27 CN CN202280057478.0A patent/CN117836878A/zh active Pending

Patent Citations (9)

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