DE102022002735A1 - System for non-contact energy transfer from a primary conductor to a secondary coil - Google Patents

Abstract

System for the contactless transmission of energy from a primary conductor to a secondary coil, which has a secondary winding and a coil core, the coil core having a constriction, in particular a constriction point.

Description

The invention relates to a system for contactless power transmission from a primary conductor to a secondary coil.

It is generally known that 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.

From the U.S. 2018/0 005 747 A1 a system for contactless energy transmission is known as the closest prior art.

From the US 2017 / 0 004 916 A1 an inductor for a system for contactless energy transmission is known.

From the EP 1 668 656 B1 an arrangement for contactless inductive transmission of electrical power is known.

From the DE 698 20 904 T2 a regulation of inductive energy absorbers is known.

From the U.S. 2014/0 084 697 A1 a system for the contactless transmission of electrical power is known.

From the U.S. 2017/0 169 942 A1 an electric power transmission system is known.

The invention is therefore based on the object of further developing a system, wherein

According to the invention, 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 arranged to be movable relative to the primary conductor, in particular on the side of the mobile part facing 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 adjoining 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.

In an advantageous embodiment, 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.

In an advantageous embodiment, 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.

In an advantageous embodiment, 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.

In an advantageous embodiment, the constriction borders on the area of the winding and/or on the area wrapped by the winding. The advantage here is that as many of the field lines emerging from the wrapped area as possible are still forced through the area of the constriction and the most efficient possible current limitation can thus be achieved.

In an advantageous embodiment, the constriction is not surrounded and/or wrapped by the winding. The advantage here is that the constriction is arranged outside the wrapped area and thus the winding slipping in, in particular the winding wire, especially when winding, is prevented in the constriction.

In an advantageous embodiment, the coil core is U-shaped,
in particular wherein the primary conductor is arranged within the space 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.

In an advantageous embodiment, the winding is a flat winding arranged in one plane.

• - von der Wicklung umfasst und/oder
• - von der senkrechten Projektion der Wicklung in die Ebene umfasst.

In particular, the perpendicular projection of the constriction is in this plane

• - covered by the winding and/or
• - embraced by the vertical 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.

In an advantageous embodiment, the coil core is E-shaped,
in particular wherein the secondary winding is wound around a middle leg of the E-shaped coil core, in particular as a flat winding,
the secondary winding being spaced from the primary conductor,
in particular where the primary conductor is laid as an elongated closed loop in the system,
in particular where a section of the primary conductor acts as a forward conductor and a return conductor arranged parallel to the forward conductor is formed by a further area of the primary conductor,
in particular wherein the yoke of the E-shaped coil core has a central limb and two outer limbs, all limbs protruding towards the plane accommodating the forward conductor and the return conductor,
in particular wherein the vertical projection of the secondary winding wound around the center leg of the E-shaped ferrite core into that plane comprises part of the forward conductor and part of the return conductor and/or part of the perpendicular projection of the forward conductor into that plane and part of the perpendicular projection of the return conductor included in this level
in particular wherein the coil core and the secondary winding are each spaced from the plane. The advantage here is that 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.

In an advantageous embodiment, 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 advantage here is that a uniform execution of the constriction can be achieved.

In an advantageous embodiment, the constriction is realized 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 wherein the recesses are spaced apart and/or are arranged one behind the other in a straight row. The advantage here is that the constriction affects the material provided for the magnetic field lines and is easy to produce.

In an advantageous embodiment, the distance between two adjacent recesses decreases monotonically as the distance from an outer edge of the coil core increases.
in particular in such a way that recesses which are arranged in the center of the coil core, in particular the yoke, and which are closest to one another are arranged closer to one another than recesses which are arranged further to the outside,
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 advantage here is that the density of the magnetic field lines is evenly distributed in the area of the constriction, i.e. local peak values of the density are avoided.

In an advantageous embodiment, the constriction has an intermediate part arranged in a continuous air gap of the coil core,
in particular where the intermediate part has 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 advantage here is that simple production is made possible. In particular, 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 one line of contact towards the rest of the coil core instead of a flat contact.

In an advantageous embodiment, the coil core and/or the intermediate part is/are coated with a layer at least on the surface areas on which the coil core rests on the intermediate part.
wherein the specific thermal conductivity of the material of the layer is smaller than the specific thermal conductivity of the material of the coil core. The advantage here is that a simple production of the thermal insulation can be achieved.

In an advantageous embodiment, at least one element is arranged between the coil core and the intermediate part,
where the specific thermal conductivity of the material of the element is smaller than the specific thermal conductivity of the material of the coil core,
in particular wherein the element is a foil or other part such as platelets. The advantage here is that a simple production of the thermal insulation can be achieved.

In an advantageous embodiment, 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 only a linear contact occurs 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.

In an advantageous embodiment, 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.

Further advantages result from the dependent claims. The invention is not limited to the combination of features of the claims. For the person skilled in the art, there are further meaningful combinations of claims and/or individual claim features and/or features of the description and/or the figures, in particular from the task and/or the task posed by comparison with the prior art.

• In der 1 ist ein berührungsloses Energieübertragungssystem mit einem seriellen Resonanzkreis schematisch skizziert.
• In der 2 ist ein berührungsloses Energieübertragungssystem mit einem parallelen Resonanzkreis schematisch skizziert.
• In der 3 ist eine Sekundärwicklung 33 mit Ferritkern 31 gezeigt, eine Ausnehmung 32, insbesondere Verengung, aufweist.
• In der 4 ist die Verengung 32 als beidseitige längliche Vertiefung, insbesondere Nut, ausgeführt.
• In der 5 ist die Verengung 32 ersetzt durch eine Reihe von durchgehenden Ausnehmungen 52 im Ferritkern 51.
• In 6 ist die Verengung 32 durch ein quaderförmiges Zwischenteil 62, welches in einem durchgehenden Spalt des Ferritkerns 61 angeordnet ist.
• In der 7 ist die Verengung 72 am insbesondere inneren Ende eines mit einer Sekundärwicklung bewickelten Schenkels eines U-förmigen Ferritkerns 71 angeordnet.
• In der 8 ist ein System zur berührungslosen Energieübertragung mit einem E-förmigen mit einer Sekundärwicklung 84 bewickelten Ferritkern 83 gezeigt, wobei die Verengung 82 an der äußeren Seite des Ferritkerns 83 angeordnet ist oder wobei die Verengung 85 an der inneren Seite des Ferritkerns 83 angeordnet ist.

The invention will now be explained in more detail using schematic illustrations:

• In the 1 a non-contact energy transmission system with a serial resonant circuit is schematically sketched.
• In the 2 a non-contact energy transmission system with a parallel resonant circuit is schematically sketched.
• In the 3 a secondary winding 33 with a ferrite core 31 is shown, having a recess 32, in particular a constriction.
• In the 4 the constriction 32 is designed as an elongated depression on both sides, in particular a groove.
• In the 5 the constriction 32 is replaced by a series of continuous recesses 52 in the ferrite core 51.
• In 6 is the constriction 32 by a cuboid intermediate part 62 which is arranged in a continuous gap of the ferrite core 61.
• In the 7 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.
• In the 8th shows a system for contactless power 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.

As in 1 shown, the system for contactless energy transmission has a primary conductor 1, which is laid elongated on the floor in a system, 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.

Energy can thus be transferred to the handset with high efficiency.

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 storage device that can be loaded from the connection of the rectifier on the DC voltage side.

Alternatively, 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 .

In 1 the inductive coupling 2 with its secondary leakage inductance L_s is shown as a schematic electrical circuit diagram.

As a further alternative, the primary conductor can be designed as a winding, with the mobile part being inductively coupled to this winding with its secondary winding.

As in 2 shown, instead of the series-connected capacitance C_k, a secondary winding connected in parallel with the secondary winding can be used. This means that lower voltages but higher currents can be achieved.

As in 3 shown, the secondary winding 33 is wound around a yoke of a U-shaped ferrite core 31, the yoke being connected to two spaced-apart legs, in particular aligned parallel to one another. 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. Because if the resonant circuit is short-circuited, 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.

In normal operation, i.e. when there is no saturation in the ferrite core 31, the area of the constriction 32 is heated, since higher losses occur here than in the rest of the ferrite core 31. The wall thickness of the ferrite core 31, in particular of the yoke of the ferrite core 31, is in the area of the constriction 32 reduced.

In 3 the legs of the U-shaped ferrite core 31 are not wound, only the yoke of the U-shaped ferrite core 31.

In 4 the constriction 32 on the ferrite core 31 is shown in an oblique view to make it clear that the constriction is formed from indentations on both sides of the ferrite core 31, which are elongated over the entire width, i.e. in particular perpendicular to the winding direction, on the ferrite core 31 and/or extend.

The indentations are preferably designed in accordance with a rectangular groove.

As in 5 shown, but instead of the indentations, recesses 52 running through the ferrite core can also be used in a row, 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.

In a further development, the distance between two adjacent recesses 52 increases with increasing distance from an outer edge, in particular in the in 3 shown section, monotonically decreasing, so in particular becoming smaller executed. Thus, the recesses 52 arranged centrally in the yoke are arranged closer to one another than the recesses 52 arranged further to the outside.

In particular, 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 .

As a further alternative, the constriction can also be implemented by inserting an intermediate part 62 into a gap in the ferrite core 61, as shown in FIG 6 shown.

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. When 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.

Advantageously, the layer is at least in those surface areas of the intermediate part 62 arranged, which rest on the ferrite core 61.

As in 7 As shown, the constriction 72 is advantageously located within the area where the secondary winding 73 is wound.

In 7 For this purpose, the left leg of the ferrite core 71 is provided with a secondary winding 73, within which the constriction 72 is arranged.

On the right leg of the U-shaped pick-up, however, 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.

As in 8th shown, instead of the U-shaped ferrite core, in particular coil core, an E-shaped ferrite core, in particular 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 perpendicular in-plane projection of the secondary winding wound around the center leg of the E-shaped ferrite core 83 includes a portion of the forward conductor 80 and a portion of the return conductor 81, specifically, it includes a portion of the perpendicular in-plane projection of the forward conductor 80 and a portion of the perpendicular projection of the return conductor 81 in the plane.

However, 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 similar to the first embodiment 4 designed as an elongated groove. The same applies to the constriction 82.

Alternatively, however, the narrowing 85 and/or 82 is similar to 5 as a series of recesses 52 passing through the ferrite core 83 or similar 6 executable as an intermediate part coated in particular with a layer.

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.

In further exemplary embodiments according to the invention, 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.

In further exemplary embodiments according to the invention, instead of such a layer, 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.

In further exemplary embodiments according to the invention, 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.

Reference List

1

primary conductor

2

inductive coupling

31

Ferrite core having yoke and two legs

32

Constriction, especially recess

33

secondary winding

51

ferrite core

52

recess

61

ferrite core

62

intermediate part

71

ferrite core

72

Recess, especially constriction

73

secondary winding

80

Area of the primary conductor 1 that acts as a forward conductor

81

Area of primary conductor 1 that acts as a return conductor

82

constriction

83

Ferrite core, especially plate-like ferrite core

84

secondary winding

L_S

Leakage inductance of the secondary winding

C_k

capacity

R_L

load

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US20180005747A1[0003]
• US20170004916A1[0004]
• EP 1668656 B1 [0005]
• DE 69820904 T2 [0006]
• US20140084697A1 [0007]
• US20170169942A1[0008]

Claims (15)

System for non-contact 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, characterized in 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 adjoining the Narrowing adjacent area of the coil core. plant after claim 1 , characterized in that the coil core, in particular ferrite core, is made of ferrite. Installation according to one of the preceding claims, characterized in that the constriction is arranged in the area of the secondary winding and/or in the area around which the secondary winding is wound and/or that the constriction is surrounded and/or wrapped by the secondary winding. plant after claim 1 or 2 , characterized in that the constriction is adjacent to the area of the secondary winding and/or to the area wrapped by the secondary winding and/or that the constriction is not surrounded and/or wrapped by the secondary winding. System according to one of the preceding claims, characterized in that the coil core is U-shaped, in particular with the primary conductor being arranged within the space surrounded by the coil core. Installation according to one of the preceding claims, characterized in that the secondary winding is a flat winding arranged in one plane and that the vertical projection of the constriction in this plane - is encompassed by the secondary winding and/or - encompassed by the vertical projection of the secondary winding in the plane is. System according to one of the preceding claims, characterized in that 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 elongated closed loop is laid in the system, in particular wherein a section of the primary conductor acts as a forward conductor and a return conductor arranged parallel to the forward conductor is formed by a further area of the primary conductor, in particular wherein the yoke of the E-shaped coil core has a central leg and two outer legs with all legs protruding towards the plane receiving the outgoing conductor and the return conductor, in particular where the perpendicular projection of the secondary winding wound around the middle leg of the E-shaped ferrite core into this plane includes part of the outgoing conductor and a T part of the return conductor and/or includes a part of the perpendicular projection of the outgoing conductor in this plane and a part of the perpendicular projection of the return conductor in this plane, in particular wherein the coil core and the secondary winding are each spaced from the plane. System according to one of the preceding claims, characterized in that the constriction has an elongated depression and/or groove on one side or both sides of the coil core, in particular the depression or groove extending perpendicularly to the magnetic flux and/or to the magnetic flux density, in particular over the entire Width of coil core. System according to one of the preceding claims, characterized in that 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 the recesses being spaced apart from one another and/or in arranged in a straight row one behind the other. plant after claim 9 , characterized in that the distance between two recesses that are closest to each other decreases monotonously 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 closer to one another than recesses that are arranged further to the outside, in particular the outer edge is the outer edge arranged in that cutting plane whose normal is oriented parallel to the passage direction of the recesses. System according to one of the preceding claims, characterized in that 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 the intermediate part being made of ferrite . plant after claim 11 , characterized in that 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 smaller than the specific thermal conductivity of the material of the coil core. plant after claim 11 or 12 , characterized in that at least one element is arranged between the coil core and the intermediate part, 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 the element being a film or another part, such as a small plate . System according to one of the preceding claims, characterized in that 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 coil core and intermediate part or element. System according to one of the preceding claims, characterized in that the secondary winding is connected in series or in parallel with such a capacitance that the resonant frequency of the resonant circuit formed in this way, in particular the oscillating circuit, corresponds to the frequency of that which is impressed on the primary conductor by a power source, in particular a feed device, of the system alternating current.

Images