DE102014202747A1 - Device for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system for a vehicle and associated method - Google Patents

Abstract

The invention relates to a device for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system for a vehicle, comprising a double winding system comprising a ferrite element, a first winding and a second winding disposed on the first winding, the second winding facing the first winding is offset by a predetermined angle, and wherein the double winding system outputs the respectively induced by the magnetic field of the primary coil of the inductive charging system in the respective winding voltage via an output interface; - An evaluation unit, which reads the induced voltages of the double winding system via an input cuts and processed so that information regarding the positional deviation of adjacent to the passive coil double winding system relative to the primary coil of the inductive charging system is determined based on the induced voltages, and wherein the evaluation unit Output interface for outputting the information regarding the specific positional deviation of the double winding system relative to the primary coil of the inductive charging system.

Description

State of the art

The increasing spread of vehicles with an electric motor as a drive unit and a battery as energy storage for the electrical energy in the vehicle requires a convenient solution for recharging the battery. Usually, in a parked vehicle, the accumulator is physically connected to an external power source by means of a charging cable, which is also referred to as a conductive charging. However, such an approach requires the driver's involvement in charging, which is considered inconvenient due to the hitherto necessary frequency of charging, and therefore complicates broader market penetration of such systems.

Instead of the conductive charging inductive charging is an innovative solution for charging the energy storage of electric vehicles. The inductive charging advantageously requires no involvement of the driver for charging, it provides protection from the weather and charging is safe against unwanted external influences. Here, typically, the primary coil of the transformer is either embedded in the street floor or designed as a floor-mounted pallet and is connected by means of suitable electronics to the power grid. The secondary coil (or passive coil) of the transformer is typically fixedly mounted in the underbody of the vehicle and in turn connected by means of associated power electronics with the vehicle battery or the energy storage. For energy transmission, the primary coil generates a high-frequency alternating magnetic field which penetrates the secondary coil and induces a corresponding current in it. Since, on the one hand, the transmittable power scales linearly with the switching frequency, and on the other hand the switching frequency is limited by the control electronics and losses in the transmission path, this results in a typical frequency range of 20 to 150 kHz.

The inductive energy transfer takes place via the air gap between the two coils. In order to realize the most efficient energy transfer, the highest possible coupling between the two coils must be achieved, which equates to minimizing the stray field. Due to physical laws, the losses increase with increasing coil spacing and the efficiency is reduced. In order to realize a high efficiency and at the same time to reduce the energy losses, therefore, the primary and secondary coils must be optimally positioned to each other, that is, both in terms of the height distance and the offset in the plane, optimally would be a concentric arrangement of the two coil at the same time a very small distance in the height direction. Experience has shown that it is hardly possible for a driver without additional aids to fulfill these requirements with regard to the positioning of the two coils when the vehicle is parked or parked in a targeted and reproducible manner, in particular with regard to the offset in the plane.

The attachment of the secondary coil on the vehicle can be done at different locations, such as on the vehicle roof, on the license plate, under the vehicle or in the area of the subsoil. As a rule, the positioning of the secondary coil under the vehicle is preferred by all automobile manufacturers due to the least possible impact on it in the event of an accident. Furthermore, the interior of the vehicle must be shielded from the magnetic fields generated during the inductive energy transfer to the secondary coil, which is why usually the vehicle underbody is shielded with a sheet of non-magnetic material, preferably aluminum, to a possible negative influence of these magnetic fields to prevent the persons in the vehicle.

One approach to contactless energy transfer is in the DE 10 2010 053 058 A1 which describes a motor vehicle device for an electric and / or hybrid motor vehicle with a charging unit, which has a power transmission unit for charging a battery device, which is provided for a contactless power transmission, and with a positioning unit, which is provided to the electric and / or Autonomously positioning a hybrid motor vehicle for a charging operation, and comprising at least one guide coil, which is provided for detecting a position of the electric and / or hybrid motor vehicle to receive an inductive contact to an inductive guide element of a charging device.

The disadvantage here is that with this structure when using a shielding plate on the subsoil no information with regard to the distance between the primary coil and the secondary coil can be determined. In addition, a plurality of coils for forming the guide coil is required so that a determination for a lateral deviation of the secondary coil can be realized by the primary coil. As a result, in addition to the required number of components for the guide coil and the cost of the evaluation of the measurement signals for determining the lateral deviation of the secondary coil of the primary coil increases. Finally, the risk of deformation of the individual coils of the guide coil through the presence of large magnetic fields very high, since the coils of the guide coil are overdriven by very large magnetic fields from the primary side, which is due to a very high induction, a rollover by the high voltage on the coil. This in turn leads to a risk of deformation of the coils of the guide coil.

Disclosure of the invention

The inventive device for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system for a vehicle and the associated inventive method for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system for a vehicle have the advantage that an optimal positioning of the passive coil on the underside of the vehicle with respect to the primary coil for the inductive charging of the energy storage in the vehicle is possible because now the driver when driving on the primary coil information regarding any necessary correction maneuvers can be provided. In addition, the present invention provides for preventing deformation of the guide coil due to the high induced voltages that may occur in the prior art.

In addition, the above-described positioning of the secondary coil with respect to the primary coil is possible with a positioning coil having only a single component, namely the double-winding system according to the invention. Thus, advantageously, the weight of the device can be reduced and costs for the device can be saved. In addition, the present arrangement can be used to prevent negative EMC effects of the cables from the positioning coil according to the prior art.

In addition, with the present device and with the associated method, a detection of the positional deviation of the secondary coil relative to the primary coil in configurations of a vehicle can take place, which has a shield plate for magnetic fields or not. Finally, parameters such as induced voltage, coupling factor, resonant circuit quality, impedance or other parameters may be used to determine one or more pieces of information regarding the positional deviation of the double coil system adjacent the passive coil from the primary coil of the inductive charging system ,

The core of the invention is to use a double winding system for determining the positional deviation of the secondary coil relative to the primary coil, with which it is possible to detect the induced voltages despite a shielding plate in the region of the underbody. On the shielding plate, the z-component of the magnetic flux density of the magnetic field of the primary coil is zero (Bz = 0). Thus, the determination of the positional deviation is possible only by detecting the other components Bx and By of the magnetic field of the primary coil, that is to say those components of the magnetic flux density of the magnetic field which describe their effect in one plane. The components Bx and By of the magnetic flux density of the magnetic field of the primary coil are not zero and are significantly larger than the component Bz. For this reason, it is advantageous if the components Bx and By of the magnetic flux density of the magnetic field are detectable. For this purpose, the double-winding system according to the invention is provided, in which two separate, but superimposed windings are formed around a ferrite element. Furthermore, the present device also comprises an associated evaluation unit that uses the detected measurement signals of the double winding system for determining information regarding the positional deviation of the adjacent to the passive coil double winding system relative to the primary coil of the inductive charging system, based on the induced voltages of the double winding system. In this case, in the present device, only a single signal processing in the evaluation unit for the received induced voltages of the double winding system for determining the information regarding the positional deviation of adjacent to the passive coil double winding system relative to the primary coil is necessary. Preferably, the evaluation unit is connected to the double winding system by means of a signal connection, but it is also possible to wirelessly transmit the induced voltages from the double winding system to the evaluation unit. The evaluation unit can be arranged together with the double winding system in a housing. Alternatively, the double winding system may be arranged separately from the evaluation unit. The evaluation unit can be designed as an independent control unit, but its functionality can also be additionally configured in an already existing control unit.

Generally applies to the present double-winding system, that the windings should each be designed with the smallest possible extent in its thickness direction, so that the windings are not far out of the subsoil. In this case, a winding with the smallest possible expansion in the z-direction takes up as much flux density as possible. Therefore, the windings are wound around the ferrite member to pass through more field lines to get the windings. With the present double-winding system, a direction detection can be realized advantageously only on the basis of the comparison of two amplitudes of a measured variable, here in particular the induced voltages of the two windings. Furthermore, a ferrite element has the property that it performs the field lines. The ferrite element will allow more field lines to pass through the winding surface because the ferrites in the ferrite element have a suction force. This results in a much larger effective area of the windings. The ferrite element is preferably formed as a plate, in particular as a square plate.

According to a further embodiment of the present device, the evaluation unit can determine from the received induced voltages of the double winding system information with regard to an angle in which the primary coil of the inductive charging system is offset relative to the double winding system in the lateral direction to the double winding system. Furthermore, the evaluation unit can determine from the received induced voltages of the double winding system information with regard to an approximate removal of the double winding system from the primary coil. In addition, it is possible to determine from the received induced voltages of the double winding system information regarding the frequency of the induced voltages of the double winding system, as well as the amplitudes of the induced voltages of the double winding system, even the absolute or relative amplitudes, for further signal processing With regard to the determination of the positional deviation of the secondary coil or the double winding system relative to the primary coil to use.

According to a further embodiment of the present device, the double-winding system can be provided to be arranged below a magnetically shielding element for the interior of the vehicle. Thus, as explained above, the present device is capable of performing the determination of the positional deviation of the secondary coil and the double winding system relative to the primary coil also for the case when only two components of the magnetic flux density of the magnetic field (especially Bx and By, see 2 ) of the primary coil can be determined.

According to a further embodiment of the present device, the magnetic field relationships of the magnetically shielding element for the interior of the vehicle in the determination of the information regarding the positional deviation of the double winding system relative to the primary coil of the inductive charging system can be considered. In this case, the fact that only two components of the magnetic flux density of the magnetic field (specifically Bx and By) of the primary coil can be determined is taken into account, so that the present double-winding system despite this limitation due to the magnetic shielding element for the interior of the vehicle for optimal and unambiguous determination of the two components of the magnetic field of the primary coil is formed in the vicinity of the magnetic shielding element for the interior of the vehicle.

According to a further embodiment of the present device, the double-winding system may be arranged substantially in the region of the center axis of the vehicle on the underside thereof, and a diagonal of the double-winding system may be congruent with the longitudinal extent of the vehicle with this. In this design of the double-winding system, in particular with a square ferrite element, the windings are each offset by 45 ° relative to the central axis of the vehicle in one direction, whereby noise of the induced voltages in the double winding system is substantially reduced, and thus an optimal determination of the positional deviation is passive coil relative to the primary coil of an inductive charging system possible.

According to a further embodiment of the present device, the second winding may be offset from the first winding by 90 °. This arrangement advantageously ensures that the signal processing in the evaluation unit is simplified and the production of the two windings on the ferrite element is simple and inexpensive to produce.

According to a further embodiment of the present device, the cross-sectional area of the first winding may be substantially the same as the cross-sectional area of the second winding. This has the advantage that one can compare the induced voltages of the two windings directly with each other, whereby the signal processing in the evaluation unit is simplified. Generally, however, in each winding, the distances from adjacent loops of a winding are preferably constant, so that a uniform detection of the magnetic field of the primary coil is possible. In addition, the two windings preferably each have an identical number of turns.

According to a further embodiment of the present device, the cross-sectional area of the first winding may be different from the cross-sectional area of the first winding different second winding. In this case, the induced voltages of the two windings are then different in size at a position of the magnetic field of the primary coil.

According to a further embodiment of the present device, the ferrite element may have a square shape, and the cross-sectional area of the first winding is substantially the same size as the cross-sectional area of the second winding. A quadratic shape of the ferrite element has the advantage that if the first winding and the second winding have exactly the same dimensions (here in particular the same cross section and the same number of turns), then the induced voltages in the respective winding are also the same. Thus, the respectively induced voltage in a winding results in U _i = N * 2π * f * B * A _secondary . Here, N denotes the number of turns, f the frequency of the magnetic field of the primary coil and A _secondarily that surface, which faces the secondary coil and is clamped on the ferrite element. Alternatively, it is also possible that the windings have different numbers of turns and different cross sections along the ferrite element, so that the induced voltage in the two windings is not the same.

• a) Bereitstellen einer erfindungsgemäßen Vorrichtung zum Erfassung einer Lageabweichung der passiven Spule gegenüber der Primärspule eines induktiven Ladesystems für ein Fahrzeug;
• b) Positionieren der Vorrichtung zum Erfassung einer Lageabweichung der passiven Spule gegenüber der Primärspule eines induktiven Ladesystems für ein Fahrzeug in den Bereich des Magnetfelds der Primärspule;
• c) Erfassen einer ersten induzierten Spannung in der ersten Wicklung des Doppelwicklungssystems und einer zweiten induzierten Spannung in der zweiten Wicklung des Doppelwicklungssystems und Ausgeben der erfassten ersten und zweiten induzierten Spannung mit Hilfe der Ausgabeschnittstelle an die Auswerteeinheit;
• d) Bestimmen, in der Auswerteeinheit, einer Information hinsichtlich der Lageabweichung des an die passive Spule angrenzenden Doppelwicklungssystems gegenüber der Primärspule des induktiven Ladesystems, basierend auf den ersten und zweiten induzierten Spannungen; und
• e) Ausgeben, von der Auswerteeinheit, der Information hinsichtlich der Lageabweichung des Doppelwicklungssystems gegenüber der Primärspule des induktiven Ladesystems an der Ausgabeschnittstelle der Auswerteeinheit.

According to the independent claim, a method for detecting a positional deviation of the passive coil relative to the primary coil of a vehicle inductive charging system is provided, comprising the steps of:

• a) providing a device according to the invention for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system for a vehicle;
• b) positioning the device for detecting a positional deviation of the passive coil relative to the primary coil of a vehicle inductive charging system in the region of the magnetic field of the primary coil;
• c) detecting a first induced voltage in the first winding of the double winding system and a second induced voltage in the second winding of the double winding system and outputting the detected first and second induced voltages by means of the output interface to the evaluation unit;
• d) determining, in the evaluation unit, information regarding the positional deviation of the double coil system adjacent to the passive coil with respect to the primary coil of the inductive charging system, based on the first and second induced voltages; and
• e) output, of the evaluation unit, the information regarding the positional deviation of the double winding system relative to the primary coil of the inductive charging system at the output interface of the evaluation unit.

Brief description of the drawings

The present invention will be explained with reference to the accompanying drawings. It shows

1 FIG. 2 is a schematic view of a double-winding system according to the present invention. FIG.

2 FIG. 2 schematically shows the general operating principle of an inductive energy transmission between two coils, as provided, in particular, for charging the energy store of a vehicle according to the present invention, FIG.

3 FIG. 2 is a schematic illustration of the underside of a vehicle with the present device for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system, wherein the primary coil is positioned centrally with respect to the center axis of the vehicle and is spaced therefrom in the longitudinal direction of the vehicle, FIG.

4 : a schematic representation of the structure according to 3 wherein the vehicle is omitted and in addition lines of the magnetic field of the primary coil are shown,

5 FIG. 2 is a schematic illustration of the underside of a vehicle with the present device for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system, wherein the primary coil is positioned laterally offset with respect to the center axis of the vehicle and is spaced therefrom in the longitudinal direction of the vehicle, FIG.

6 : a schematic representation of the structure according to 5 wherein the vehicle is omitted and in addition lines of the magnetic field of the primary coil are shown,

7 FIG. 2: a schematic view of the course of the individual components of the magnetic flux density of the primary coil and the induced voltage in the present double-winding system in the arrangement of the double-winding system on the secondary coil, FIG.

8th FIG. 2 is a schematic view of the course of the individual components of the magnetic flux density of the magnetic field of the primary coil and the induced voltage in the present double-winding system in the arrangement of the double-winding system outside the secondary coil, and FIG

9 to 11 a sequence of different positions of a vehicle when driving to a primary coil of an inductive charging system, and the course of an induced voltage in the double-winding system according to the present invention.

Embodiments of the invention

In the following embodiments, the same reference numerals refer to the same elements across the individual figures.

1 shows a schematic view of a double winding system 100 according to the present invention. In this case, the double winding system 100 a ferrite element 10 , a first winding 20 and one on the first winding 20 arranged second winding 30 on. The second winding 30 is opposite the first winding 20 offset by an angle of 90 °. The first winding 20 gives a first induced voltage at a first terminal 25 which is induced upon approaching a magnetic field in the first winding. The second winding 30 gives a second induced voltage at a second terminal 35 which is induced upon approaching a magnetic field in the second winding. The double winding system 100 are each of the magnetic field of the primary coil (not shown) of the inductive charging system (not shown) in the respective winding 20 . 30 induced voltages via an output interface (not shown).

The ferrite element 10 has a square shape in the manner of a plate, and the cross-sectional area of the first winding 20 is the same size as the cross-sectional area of the second winding 30 , A square shape of the ferrite element 10 has the advantage that if the first winding 20 and the second winding 30 have exactly the same properties (in particular the same cross section and the same number of turns), then the induced voltages in the respective winding are also the same size. In addition, in every winding 20 . 30 the distances of adjacent loops of a winding are each constant, so that a uniform detection of the magnetic field of the primary coil is possible. In addition, the two windings point 20 . 30 each an identical number of turns on.

2 schematically shows the general operating principle of an inductive energy transfer between two coils, as provided in particular for charging the energy storage (not shown) of a vehicle (not shown) according to the present invention.

This is done by a primary coil 200 generates a magnetic field which is schematically represented in its shape by a plurality of arrows. A secondary coil 300 , Which for the most efficient energy transfer as close as possible with regard to the vertical distance of the two coils 200 . 300 and should be positioned concentric with each other, is penetrated by a part of the magnetic field, which from the primary coil 200 is produced. This will be in the secondary coil 300 induces a voltage (not shown). A common convention for designating the individual components of the magnetic flux density of the magnetic field of the primary coil 200 denotes the component of the magnetic flux density of the magnetic field with Bz, which extends from the center of the primary coil 200 extending in both directions from the plane passing through the primary coil 200 is formed. In this case, the positive direction of the component Bz is that direction, that of the primary coil 200 to the secondary coil 300 runs. Accordingly, those components of the magnetic flux density of the magnetic field are denoted by Bx and By, which are derived from the center of the primary coil 200 in the plane of the primary coil 200 extend, which are orthogonal to each other. The components Bx, By and Bz define a rectangular coordinate system for describing the location and the respective strength of the magnetic flux density of the magnetic field of the primary coil 200 ,

Referring to 3 and 4 Now, an overall arrangement of the present apparatus for detecting a positional deviation of the passive coil relative to the primary coil of a vehicle inductive charging system, wherein the primary coil 200 positioned centrally with respect to the central axis of the vehicle and spaced from it in the longitudinal direction of the vehicle. It shows 3 a schematic representation of the underside of the vehicle with the present device for detecting a positional deviation of the passive coil relative to the primary coil 200 an inductive charging system. 4 shows a schematic representation of the structure according to 3 with the vehicle omitted and in addition lines of the magnetic field of the primary coil 200 are shown.

The double winding system 100 is right in front of the secondary coil 300 arranged with ferrites, since in this area the magnetic flux density due to the ferrite of the secondary coil 300 is greatest. The double winding system 100 is arranged such that it is centered with respect to the central axis of the vehicle and in the longitudinal direction of the vehicle in front of the secondary coil 300 is arranged. The double winding system 100 is arranged substantially in the region of the central axis of the vehicle on its underside, and a diagonal of the double-winding system 100 is with respect to the longitudinal extent of the vehicle with this congruent. In addition, the double winding system 100 arranged on the underside of the vehicle such that its windings are each offset by 45 ° with respect to the center axis of the vehicle in one direction, whereby noise of the induced voltages in the double winding system is substantially reduced, and thus with respect to an optimal determination of the positional deviation of the passive coil the primary coil of an inductive charging system is possible. In addition, the two windings of the double winding element 100 offset by 90 ° to each other.

The vehicle has a magnetically shielding element 50 for the interior of the vehicle, which is preferably designed as a sheet of aluminum or an aluminum alloy. Will now the vehicle in the direction of the primary coil 200 moved (see the double arrow to indicate the direction of travel of the vehicle), so the induced voltages in both windings of the double winding system 100 due to the central arrangement of the primary coil 200 same size in relation to the central axis of the vehicle. The triangles 60 . 70 symbolize each case the height of the induced voltage for a winding of the double winding system 100 at the appropriate location along the distance between the double winding system 100 and the primary coil 200 , As mentioned above, the two triangles are the same size, that is, the vehicle is moved on an optimal path to the primary coil 200 to, so that as efficient as possible inductive charging of the energy storage device (not shown) of the vehicle can be realized in this case.

4 additionally illustrates the central positioning of the primary coil 200 with respect to the secondary coil 300 and thus also on the double winding system 100 along a central axis 90 of the vehicle (not shown). In addition, there are lines of the magnetic field of the primary coil 200 shown as they approach the double winding system 100 act on this.

Referring to 5 and 6 Now, an overall arrangement of the device for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system for a vehicle will be explained, wherein the primary coil 200 Positioned laterally offset with respect to the center axis of the vehicle and spaced from it in the longitudinal direction of the vehicle. 5 shows a schematic representation of the underside of a vehicle with the present device for detecting a positional deviation of the passive coil relative to the primary coil 200 an inductive charging system. 6 shows a schematic representation of the structure according to 5 with the vehicle omitted and in addition lines of the magnetic field of the primary coil 200 are shown.

In this situation, since the configuration of the passive coil position deviation detecting device with respect to the primary coil of a vehicle inductive charging system is the same as that according to FIG 3 is, should at this point only the effect of the laterally offset arrangement of the primary coil 200 opposite the double winding system 100 be explained.

Will the vehicle be moving towards the primary coil 200 moved (see the double arrow to indicate the direction of travel of the vehicle), so the induced voltages in both windings of the double winding system 100 due to the laterally offset arrangement of the primary coil 200 different in size with respect to the central axis of the vehicle. The triangles 60 . 70 in turn each symbolize the height of the induced voltage for a winding of the double winding system 100 at the appropriate location along the distance between the double winding system 100 and the primary coil 200 , Because the double winding system 100 no longer in the middle of the primary coil 200 is positioned, there is a voltage difference with respect to the magnitude of the induced voltages of the two windings of the double winding system 100 , Because in this example by the left triangle 70 Passing through more field lines in its surface, the voltage amplitude in this winding is greater than in the right triangle 60 ,

In this way, the present device for detecting a positional deviation of the passive coil from the primary coil of a vehicle inductive charging system can determine that the vehicle is not on an optimal path to the primary coil 200 to move, which would lead to an inefficient inductive charging of the energy storage (not shown) of the vehicle without a correction by the driver after stopping the vehicle. In addition, the present device may also determine to which side the primary coil 200 opposite the double winding system 100 (and thus the secondary coil 300 ), so that a corresponding feedback to the driver when driving on the primary coil 200 is possible.

6 additionally illustrates the laterally offset positioning of the primary coil 200 with respect to the secondary coil 300 and thus also on the double winding system 100 along a central axis 90 of the vehicle (not shown). In addition, there are lines of the magnetic field of the primary coil 200 shown as they approach the double winding system 100 act on this. The right side of 6 also shows a Sectional view through the arrangement, which of the magnetic shielding element 50 for the interior of the vehicle, the double winding system 100 , the primary coil 200 and the secondary coil 300 is formed. The primary coil 200 is at a distance d below the bottom of the magnetically shielding element 50 staggered.

7 shows a schematic view of the course of the individual components of the magnetic flux density of the primary coil (not shown), and the induced voltages (equal in size) in the present double-winding system 100 in the arrangement of the double winding system on the secondary coil 300 , The double winding system 100 and the secondary coil 300 are on the bottom of a magnetically shielding element 50 arranged. The secondary coil 300 is centered in a rectangular shaped plate-shaped ferrite body 250 arranged.

In this arrangement is for the present double-winding system 100 Detecting the components of the magnetic flux density of the magnetic field of the primary coil not possible in all directions (Bz, By, Bx). Under the ferrite body 250 all components of the magnetic flux density of the magnetic field are present. However, as soon as the area of the ferrite body 250 ends, the component Bz of the magnetic flux density of the magnetic field disappears. However, the components Bx and By are still present and can by the double winding system 100 be detected.

8th shows a schematic view of the course of the individual components of the magnetic flux density of the magnetic field of the primary coil (not shown) and the induced voltage in the present double-winding system 100 in the arrangement of the double winding system 100 outside the secondary coil 300 , The double winding system 100 and the secondary coil 300 are on the bottom of a magnetically shielding element 50 arranged. The secondary coil 300 is centered in a rectangular plate-shaped ferrite body 250 arranged.

In this case, for the present double-winding system 100 Detecting all components of the magnetic flux density of the magnetic field of the primary coil not in all directions (Bx, By, Bz) possible. The component Bz of the flux density B is in the region of the magnetic shielding element 50 Zero. The present double winding system 100 can, however, with the existing components Bx and By information regarding the positioning of the double winding system 100 to the primary coil based on the induced voltages as described above.

9 to 11 show a sequence of different positions of a vehicle 500 when driving on a primary coil 200 an inductive charging system, and the course of an induced voltage in the double-winding system (not shown) according to the present invention.

It should be using the double winding system and the output induction voltage secondary coil 300 which is on the bottom of the vehicle 500 is installed, via the primary coil 200 At the parking lot 400 be optimally positioned so that a subsequent inductive charging of the energy storage (not shown) of the vehicle 500 as efficiently as possible. The 9 to 11 exemplify the process of detecting the distance of the vehicle 500 in the longitudinal direction of the primary coil 200 and the feedback to the driver for the best possible positioning of the vehicle 500 towards the parking position.

To the secondary coil 300 and the primary coil 200 in the park position, factors such as the induced voltage, a coupling factor, the resonant circuit quality, the impedance or other parameters may be used. In the following detection of the distance of the double winding system in the longitudinal direction of the vehicle 500 to the primary coil 200 only the induced voltage is used because it is easiest to measure.

The 9 to 11 show the qualitative profile of the induced voltage U _is in the double winding system as a function of the distance x of the double winding system from the primary coil 200 , The distance x = 0 indicates the parking position in which the two coils 200 . 300 are arranged congruent to each other, and the inductive charging of the energy storage of the vehicle 500 he follows.

From a certain distance (depending on the strength of the magnetic field of the primary coil 200 ), the double winding system, the magnetic field of the primary coil 200 detect. However, the induced voltage at this distance is still very low and the vehicle 500 must continue to drive x in the longitudinal direction until the induced voltage U _is the level of a target voltage U _soll reached, which represents the achievement of the parking position. The setpoint voltage U _is determined on the basis of (several) measurements and simulations. The actual magnitude of the induced voltage U _is for clarity, with a point P in the 9 to 11 characterized.

9 shows that the distance x of the vehicle 500 to the loading point is still large, and thus the induced voltage U _is low at this point and is far below the setpoint U _soll . This is the case, for example, in the dashboard (not shown) of the vehicle 500 a graphical display (not shown) which provides the driver in the form of a colored spot of light 600 the current distance of the vehicle 500 from the parking position so that it can easily control the parking position based on the feedback. In this case, the driver receives by means of a red light point the request further in the longitudinal direction of the primary coil 200 to drive out until the desired value V _{set is} for the induced voltage U has been reached. However, those skilled in the art will readily recognize that a variety of optical, auditory and haptic feedbacks are conceivable for this purpose, and thus the present invention is not limited thereto.

10 shows the position of the vehicle 500 , which now moved closer to the loading point in the longitudinal direction. In this position, the induced voltage U _{ist is} greater than in the previous position according to FIG 9 because the windings (not shown) of the double winding system are closer to the primary coil 200 are positioned. The point P on the voltage curve shows the instantaneous voltage induced in the windings according to the distance of the vehicle 500 to the parking position. The display reacts to the reduced distance in the longitudinal direction in that now another color for the light spot 600 , here yellow, for example, expresses that the parking position is almost reached. The choice of colors is arbitrary and the assignment of a color to a predetermined distance is well known to those skilled in the art.

If the vehicle 500 now continues in the longitudinal direction, then it finally reaches the parking position (see 11 ). In this position, then the target voltage U _is achieved and the vehicle 500 should now be turned off to charge its energy storage. The driver sees that the parking position in the display has been reached using the light point 600 , which is shown in green here, for example. Now starts the inductive charging of the energy storage of the vehicle 500 , The point P of the induced voltage on the voltage curve in the right area of 11 is in this case at the level of the desired value U _soll.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102010053058 A1 [0005]

Claims (10)

Device for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system for a vehicle, comprising - a double-winding system ( 100 ), which is a ferrite element ( 10 ), a first winding ( 20 ) and one on the first winding ( 20 ) arranged second winding ( 30 ), wherein the second winding ( 30 ) with respect to the first winding ( 20 ) is offset by a predetermined angle, and wherein the double winding system ( 100 ) each of the magnetic field of the primary coil of the inductive charging system in the respective winding ( 20 . 30 ) outputs induced voltage via an output interface; An evaluation unit which measures the induced voltages of the double-winding system ( 100 ) read in via an input section and processed in such a way that information regarding the positional deviation of the double-winding system adjacent to the passive coil (FIG. 100 ) is determined relative to the primary coil of the inductive charging system based on the induced voltages, and wherein the evaluation unit has an output interface for outputting the information concerning the particular positional deviation of the double-winding system ( 100 ) relative to the primary coil of the inductive charging system. Apparatus according to claim 1, characterized in that the evaluation unit from the received induced voltages of the double winding system ( 100 ) Determines information with respect to an angle in which the primary coil of the inductive charging system with respect to the double winding system ( 100 ) in the lateral direction to the double winding system ( 100 ) is offset. Device according to claim 1 or 2, characterized in that the double winding system ( 100 ) is provided below a magnetic shielding element ( 50 ) to be arranged for the interior of the vehicle. Device according to one of the preceding claims, characterized in that the magnetic field conditions of the magnetically shielding element ( 50 ) for the interior of the vehicle in determining the information regarding the positional deviation of the double-winding system ( 100 ) are taken into account with respect to the primary coil of the inductive charging system. Device according to one of the preceding claims, characterized in that the double winding system ( 100 ) is arranged substantially in the region of the center axis of the vehicle on its underside, and that a diagonal of the double-winding system ( 100 ) with respect to the longitudinal extent of the vehicle is congruent with this. Device according to one of the preceding claims, characterized in that the second winding ( 30 ) with respect to the first winding ( 20 ) is offset by 90 °. Device according to one of the preceding claims, characterized in that the cross-sectional area of the first winding ( 20 ) is substantially the same size as the cross-sectional area of the second winding ( 30 ). Device according to one of claims 1 to 6, characterized in that the cross-sectional area of the first winding ( 20 ) from the cross-sectional area of the second winding ( 30 ) is different. Device according to one of claims 1 to 6, characterized in that the ferrite element ( 10 ) has a square shape and the cross-sectional area of the first winding ( 20 ) is substantially the same size as the cross-sectional area of the second winding ( 30 ). A method for detecting a positional deviation of the passive coil relative to the primary coil of a vehicle inductive charging system, comprising the steps of: a) providing a device for detecting a positional deviation of the passive coil relative to the primary coil of an inductive charging system for a vehicle according to one of claims 1 to 9 ; b) positioning the device for detecting a positional deviation of the passive coil relative to the primary coil of a vehicle inductive charging system in the region of the magnetic field of the primary coil; c) detecting a first induced voltage in the first winding ( 20 ) of the double winding system ( 100 ) and a second induced voltage in the second winding ( 30 ) of the double winding system ( 100 ) and outputting the detected first and second induced voltages by means of the output interface to the evaluation unit; d) determining, in the evaluation unit, information regarding the positional deviation of the double winding system adjacent to the passive coil ( 100 ) to the primary coil of the inductive charging system based on the first and second induced voltages; and e) output, by the evaluation unit, of the information regarding the positional deviation of the double-winding system ( 100 ) relative to the primary coil of the inductive charging system at the output interface of the evaluation unit.

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