Patent Application
20170243691
The invention relates to a coil assembly for inductive energy transmission and to an inductive energy transmission device. The present invention further relates to a method for manufacturing a coil assembly for inductive energy transmission.
Electric vehicles, which are driven solely by means of an electric motor, are known. In addition, plug-in hybrids are also known, which are driven by means of a combination of an electric motor and one further drive machine. In this case, the electric energy for driving the electric motor is provided by an electrical energy accumulator, for example, a traction battery. After the energy accumulator has been completely or partially discharged, the energy accumulator must be recharged. There are various approaches for charging the energy accumulator.
On the one hand, it is possible to galvanically connect the electric vehicle to a charging station by means of a suitable charging cable. For this purpose, the user must establish an electrical connection between the electric vehicle and the charging station. This can be perceived as being unpleasant, in particular during adverse weather conditions, such as rain, for example. Due to the very limited electrical range of electric and plug-in hybrid vehicles, this cable connection must also be established very often by the user, which is perceived by many users as a great disadvantage of electric vehicles as compared to conventional vehicles.
Therefore, on the other hand, there are also wireless solutions for transmitting energy from a charging station to an electric vehicle. In this case, the energy is inductively transmitted from the charging station via a magnetic alternating field from a primary coil to a secondary coil in the electric vehicle and is fed to the traction battery in the vehicle.
In order to form the primary coil, a high frequency stranded wire (also referred to as an HF stranded wire), among other things, is used, which consists of a relatively large number of fine wires which are insulated from one another and are interwoven in such a way that every single wire, in the statistical mean, assumes preferably every point in the total cross-section of the stranded wire equally often.
DE 10 2013 010 695 A1 describes a primary winding assembly which comprises a winding assembly and a winding wire. In one advantageous embodiment, an HF stranded wire is used as the winding wire, wherein the stranded wire is designed as a bundle of individual wires which are electrically insulated from one another.
The invention provides a coil assembly for inductive energy transmission, and an inductive energy transmission device, and a method for manufacturing a coil assembly.
Thus, the following is provided:
A coil assembly for inductive energy transmission, comprising an electrically non-conductive substrate which has a first side and a second side; a plurality of strip conductors which are disposed on the first side and on the second side of the substrate, and which form a coil for inductive energy transmission; a plurality of vias in the substrate for routing the strip conductors through the substrate; wherein at least two of the plurality of strip conductors are disposed in a twisted manner in relation to each other in the substrate.
Furthermore, an inductive energy transmission device comprising at least one coil assembly according to the invention is provided.
In addition, a method is provided for manufacturing a coil assembly for inductive energy transmission, which includes the following method steps of: providing an electrically non-conductive substrate which has a first side and a second side; forming a plurality of strip conductors on the first side and on the second side of the substrate for forming a coil for inductive energy transmission, wherein at least two of the plurality of strip conductors are disposed in a twisted manner in relation to each other in the substrate.
The idea underlying the present invention is that of using, instead of a wound HF stranded wire, a substrate comprising strip conductors, which are formed thereon and are twisted in relation to each other, as the coil for inductive energy transmission.
Due to the use of a substrate for implementing the stranded wire, several advantages can be simultaneously achieved and more functions can be covered than simply generating the magnetic alternating field. In addition, the simple possibility of partial reactive power compensation of individual windings is achieved, whereby the maximum resonance voltage that occurs can be limited.
A further advantage of the coil assembly presented here is the very simple production using known technologies. For example, the coil assembly can be produced, e.g., as a multilayer circuit board (PCB) or, e.g. as an LTCC circuit board (ceramic). In this case, e.g., substrate segments are simply produced using conventional technology, the components are installed thereon, and the segments are then assembled or, e.g., in the case of smaller coil systems, the entire coil system is produced on a single substrate.
Due to the formation of an HF stranded wire from twisted strip conductors on a substrate, the electromagnetic properties of the coil can be highly exactly adjusted and even precalculated, e.g., it is now possible, by way of twisting with a low filling factor, to reduce the mutual influence of the individual wires and individual windings as compared to a conventional stranded wire.
In this context, “twisted” means that at least two strip conductors extend alternately through the vias from the first side of the substrate to the second side of the substrate and back to the first side of the substrate. In this way, the strip conductors are twisted in relation to each other and are helically wound around one another.
The coil for inductive energy transmission, which is formed by the strip conductors, can be disposed on the substrate in different ways. For example, the coil formed from the strip conductors can be a duolateral coil, a basket coil, a honeycomb coil, or a coil wound in a different way. In this way, the coil can be well adapted to the particular requirements.
The strip conductors swap their positions with one another along their entire course and/or at certain points. The lay ratio is between 1.001 and 2.0, in particular between 1.02 and 1.04 in this case.
The twisting is not limited to only two strip conductors, of course, but rather it is possible for any number of strip conductors to extend so as to be twisted in relation to each other. For example, three strip conductors, four strip conductors, five strip conductors, ten strip conductors, or all strip conductors can be twisted in relation to each other.
Although the subdivision into individual strip conductors results in a lower filling factor overall, a low filling factor can be used for minimizing, e.g., proximity and/or skin effects, by way of an artful magnetic design. According to one preferred refinement, the substrate is formed from multiple substrate segments. For example, the substrate can be formed from multiple substrate segments which have been produced using known technologies, and can be subsequently assembled. In this way, the coil assembly can be adapted to the particular field of application in a very simple way. Furthermore, costs can be reduced as a result of this design, since existing production systems can be used for producing the coil assembly.
According to one further preferred refinement, the substrate segments are designed to be symmetrical with respect to shape. Due to this design of the coil assembly, costs can be further reduced, since the formation of substrate segments which are symmetrical with respect to shape has advantages with respect to production engineering, in particular in large quantities.
According to yet another preferred refinement, the substrate is formed from multiple circular ring segment-shaped substrate segments. For example, the substrate is formed from 2, 3, 4, 5, 6, 7, 8 or more individual substrate segments. The substrate segments can then be assembled to form a circle, or another shape, e.g., a quadrangle, and thereby form a single substrate. Due to this design, the production costs and the overall manufacturing costs can be reduced, since the production of identically designed substrate segments can take place in an automated manner and in large quantities.
According to yet another preferred refinement, the substrate or a substrate segment comprises a strip conductor section which is designed for the variable interconnection of the strip conductors. For example, one substrate segment comprises a strip conductor section which electrically couples two, three or more strip conductors or strip conductor sections to one another. Due to this design, the number of windings and/or the winding cross-section of the coil can be adapted to the particular application in an easy way without the need to change all the substrate segments or the entire substrate.
According to yet another preferred refinement, the strip conductor section comprises active switches for adjusting the number of windings and/or the winding cross-section, in order to allow for a variable interconnection. The switches can be designed, for example, as semiconductor switches or relays, and can be controllable via a control device. In this way, the number of windings and/or the winding cross-section of the coil can be adjusted during the operation of the coil.
According to one preferred refinement, capacitors are disposed between adjacent substrate segments for interconnecting the strip conductors of the substrate segments. For example, ceramic capacitors are used for interconnecting the individual substrate segments. Ceramic capacitors can be produced in the desired shape in an easy way due to the easy moldability of the ceramic base. Furthermore, ceramic capacitors are virtually non-flammable. Furthermore, ceramic capacitors can be manufactured in the form of SMD multilayer ceramic chip capacitors (MLCC) in a technically favorable and cost-favorable way as surface-mountable components. The capacitors can also be designed, e.g., as plastic-film capacitors, however.
According to yet another preferred embodiment, the substrate comprises multiple substrate layers, wherein the strip conductors are formed on both sides of the individual substrate layers. Due to the design of the substrate having multiple substrate layers, a multilayer circuit board can be formed, which has a larger number of strip conductors and, therefore, coil windings and/or winding cross-section. For example, a substrate comprises 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or any number of substrate layers. In this way, the coil assembly can be adjusted to the particular field of application in an easy way.
According to yet another preferred refinement, capacitors are disposed on the substrate, which are designed for the reactive power compensation of the coil. Due to the formation of the coil on a substrate, multiple capacitors can be used, since sufficient space is available with this design. Furthermore, due to this formation, the waste heat from the capacitors can be dissipated via the substrate in a particularly effective way. In addition, compensation can be implemented in a section-wise manner, whereby the maximum resonance voltages that occur can be reduced, with advantages with respect to electromagnetic compatibility and insulation requirements.
Preferably, the reactive power compensation is distributed to at least two capacitors which are disposed on two different strip conductors and/or strip conductor sections and/or substrate segments. In this way, it is possible to carry out the reactive power compensation in a section-wise and/or segment-wise manner. Due to a distributed reactive power compensation, advantages result in terms of the electromagnetic compatibility (EMC) and the insulation requirements, since the maximum resonance voltage that occurs can also be reduced in a section-wise manner.
According to yet another preferred refinement, the strip conductors are designed to be tapered in the region of the vias. In this way, a higher packing density of the strip conductors in the substrate can be achieved. Furthermore, the extent of twisting of the individual strip conductors can be increased in this way.
Further features and advantages of the present invention are described in the following on the basis of embodiments and with reference to the figures.
In the drawings:
In the figures, identical reference numbers designate elements that are identical or are functionally identical.
As is apparent, the strip conductor sections 33 and 34 are twisted in relation to each other. This means that the strip conductor sections 33 and 34 extend alternately through the vias 4 from the first side 10 to the second side 11 and back to the first side 10. In this way, the strip conductors 30 are formed so as to be twisted in relation to each other.
Due to the formation of the coil 50 on the substrate 2, it is likewise possible to place practically any number of capacitors 8 which are required for the reactive power compensation during the inductive energy transmission. Due to a design of this type, it is possible to use, e.g., SMC ceramic capacitors for section-wise reactive power compensation instead of the plastic-film capacitors which are common nowadays. Advantages also result with respect to the cooling of the capacitors 8 when the capacitors can be distributed over a larger area. Further advantages result with respect to electromagnetic compatibility (EMC) and insulation requirements due to a distributed reactive power compensation, since the maximum resonance voltage that occurs can be reduced. The coil assembly 1 for inductive energy transmission, which is depicted in
The inductive energy transmission and the coil assembly according to the invention can also be used, for example, for contactlessly charging power tools, e-bikes, household devices, and consumer electronics devices.
The type of twisting and the type of winding can also be adapted to the particular field of application and the particular basic conditions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 220 978.1 | Oct 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/067275 | 7/28/2015 | WO | 00 |
