Method for positioning a vehicle

Abstract

The invention relates to a method for positioning a vehicle (2) having a mobile inductive charging device (1a) in a defined position in relation to a stationary inductive charging device (1b). A positioning signal is generated in one of the two inductive charging devices (1a, 1b). The positioning signal induces at least one voltage signal (13a, 13b) in the other of the two inductive charging devices (1a, 1b). A relative distance between the mobile inductive charging device (1a) and the stationary inductive charging device (1b) is approximated from the induced voltage signal (13a, 13b).

Description

[0001] Method for positioning a vehicle

[0002] The invention relates to a method for positioning a vehicle according to the preamble of the independent patent claim. The invention further relates to a graphic display element for a vehicle.

[0003] US10541551 B2 proposes guiding a vehicle to a location defined by an x- and y-value by evaluating the magnitude of an induced voltage. However, the method involves a relatively complicated calculation.

[0004] The present invention is concerned with the object of providing improved or at least alternative embodiments for a method for positioning a vehicle of the type mentioned at the outset.

[0005] The present invention proposes a method for positioning a vehicle with a mobile inductive charging device in a defined position relative to a stationary inductive charging device, wherein a positioning signal is generated in one of the two inductive charging devices and the positioning signal induces at least one voltage signal in the other of the two inductive charging devices, and a relative distance between the mobile inductive charging device and the stationary inductive charging device is approximated from the induced voltage signal.

[0006] The term "inductive charging device" therefore refers to only one of at least two components required for energy transfer during an inductive charging process. During the inductive charging process, a power transfer coil generates an alternating magnetic field during the energy transfer in an inductive charging device. This alternating magnetic field induces a voltage in another power transfer coil of another inductive charging device. This additional inductive charging device thus serves as a counterpart for this specific charging process. The energy is transferred wirelessly and absorbed by induction of a voltage.

[0007] A stationary inductive charging device is the non-mobile part of a vehicle charging system, i.e. the part that does not move with the vehicle.

[0008] A stationary inductive charging device can preferably be located on, at, or in a floor. This can be an inductive charging device mounted on the ground or an inductive charging device sunk into a subsurface or into the ground. A floor can be a roadway, a parking lot surface, a garage floor, a floor in a parking garage, or another building. However, a stationary inductive charging device can also be located on walls or similar surfaces.

[0009] A mobile inductive charging device can be installed on and / or in a vehicle. Generally, this refers to the part of a

[0010] A vehicle charging system is understood to mean a device that moves with the vehicle. An inductive charging device on and / or in the vehicle is therefore suitable for absorbing the magnetic field and making electrical energy available from a vehicle's energy storage device, for example, a battery or accumulator in the vehicle.

[0011] For efficient energy transfer, the mobile inductive charging device must be positioned as precisely as possible in relation to the stationary inductive charging device. The mobile inductive charging device must therefore be positioned in a defined position in relation to a stationary inductive charging device. The defined position is a predetermined position which preferably takes into account that energy transfer can take place with the highest possible efficiency. In particular, it can be taken into account that one energy transfer winding in each of the two inductive charging devices is positioned opposite one another with the smallest possible distance from one another and with regard to an air gap between them. Since both energy transfer windings generally do not have to be the same size, symmetrical positioning in which the winding axes of the two energy transfer windings lie as close to one another as possible is also advantageous.Exact positioning is often difficult or impossible for the driver without additional support in the form of a driver assistance system.

[0012] A positioning signal can be an alternating electromagnetic or magnetic field, which can induce a voltage signal in the other of the two inductive charging devices. It is possible that the positioning signal is transmitted or generated directly by a power transmission winding of an inductive charging device, or that one or more additional windings or another signal generation device is present for this purpose.

[0013] The positioning signal preferentially transmits power that is significantly lower than the power transmitted during energy transmission.

[0014] If a positioning signal is generated in the stationary inductive charging device, it induces a voltage in the mobile inductive charging device. If a positioning signal is generated in the mobile inductive charging device, it induces a voltage in the stationary inductive charging device.

[0015] The respective inductive charging device can be a larger unit, with the energy transfer components constituting only a part of the inductive charging device. The fact that a positioning signal is generated "in" an inductive charging device or that a voltage signal is generated "in" an inductive charging device means that this takes place within this larger unit.

[0016] During the positioning process, it is important for the driver of a vehicle to receive information about the relative distance to the target position. This allows them to gradually adjust their speed accordingly or prepare for braking. A relative distance is a value that changes continuously, preferably proportionally with the distance, as the distance changes, but which does not necessarily provide information about the absolute distance in meters. During a positioning process, it is sufficient for a driver to receive information about the relative distance to the target position, for example, via a graphic display element. Information about the absolute distance is not necessary. While other relative methods are based on the comparison of several signals, this method uses the magnitude of an induced voltage to determine a relative distance.A relative distance is then approximated from the induced voltage. This means that the measured induced voltage is used in a calculation that is at least partially based on an approximation. This can, for example, be a polynomial approximation that approximates the nonlinear relationship between a voltage induced by an alternating magnetic field and the distance to the transmitter of the magnetic field. The approximate determination of the absolute distance in meters generally requires complex calibration. The combination of an approximate calculation with a purely relative determination of the distance is advantageous because it is a simple way to provide a driver with the necessary information without the need for complex calibration.

[0017] Preferably, the mobile inductive charging device or the stationary inductive charging device has a first sensor winding and a second sensor winding, which are arranged symmetrically to the vehicle longitudinal direction or to the desired vehicle longitudinal direction, and the positioning signal generates a first voltage signal in the first sensor winding and a second voltage signal in the second sensor winding, and an approximate relative distance value is determined from the sum of the two voltage signals, and a directional deviation value between the vehicle longitudinal direction and the desired vehicle longitudinal direction is determined from the comparison of the two voltage signals to one another.

[0018] The first and / or the second sensor winding can be arranged in or near the mobile or stationary inductive charging device.

[0019] In general, a coil is defined here as a component for generating or receiving a magnetic field. A coil can consist of a winding and optionally other elements such as a magnetic core and a coil carrier. A winding is a wound arrangement of a current conductor. A winding can consist of one or more turns, with one turn representing one full circuit of a conductor. In general, however, a winding can also consist of fewer than one turn, for example, 0.5 turns. Of course, a partial number of turns, such as 2.5 turns, is also possible.

[0020] A sensor winding according to the invention can be designed in different forms and can have half, one, or preferably several turns. A conductor of such a sensor winding can, for example, have a cross-sectional area between 0.01 mm 2 and 2 mm 2A conductor can be designed as a stranded wire, as a single conductor, or in another form, for example in the form of conductor tracks on printed circuit boards.

[0021] If the sensor windings are located in a mobile inductive charging device, they are aligned symmetrically to the vehicle's longitudinal direction. If the sensor windings are located in a stationary inductive charging device, they are aligned symmetrically to the vehicle's desired longitudinal direction.

[0022] A stationary inductive charging device has a target vehicle longitudinal direction. This is the direction in which the vehicle's longitudinal direction should be after a successful positioning process.

[0023] A symmetrical arrangement of the two sensor windings for

[0024] Vehicle longitudinal direction or to the desired vehicle longitudinal direction means that the angle between the first sensor winding and the vehicle longitudinal direction / desired vehicle longitudinal direction is at least approximately equal to the angle between the second sensor winding and the vehicle longitudinal direction / desired vehicle longitudinal direction, whereby the two sensor windings are arranged axially symmetrically in the vehicle longitudinal direction / desired vehicle longitudinal direction, mirrored. The symmetrical arrangement is advantageous because - in addition to the relative distance - a directional deviation can be determined by simply comparing the voltages induced in both sensor windings. The two sensor windings can, for example, be arranged at a 45° angle to the vehicle longitudinal direction or to the desired vehicle longitudinal direction. The positioning signal can be symmetrical to the vehicle longitudinal direction or to the desired vehicle longitudinal direction.In particular, the positioning signal can have a main direction of the magnetic field in the vehicle longitudinal direction or in the desired vehicle longitudinal direction.

[0025] Advantageously, the positioning signal is generated by a positioning signal winding with a winding axis in the vehicle longitudinal direction or desired vehicle longitudinal direction.

[0026] If the positioning signal winding is located in a mobile inductive charging device of a vehicle, the winding axis of the positioning signal winding is advantageously aligned in the longitudinal direction of the vehicle.

[0027] If the positioning signal winding is located in a stationary inductive charging device, the winding axis of the positioning signal winding is advantageously aligned in the desired vehicle longitudinal direction.

[0028] Such an arrangement generates a magnetic field with a primary direction of the magnetic field lines in the longitudinal direction of the vehicle or in the desired longitudinal direction of the vehicle. This has the advantage that this design enables a significantly greater range for positioning than would be the case with a positioning signal generated by a power transmission winding with the same power or the same magnetic field strength. Furthermore, this orientation of the magnetic field is also particularly well suited to enabling the simplest possible detection of a positional or angular deviation in the sensor windings.

[0029] The positioning signal winding can be designed as a solenoid coil, also called a cylinder coil.

[0030] Particularly preferably, the positioning signal winding is designed such that it has a particularly large extension in the travel plane and perpendicular to the longitudinal direction of the vehicle or to the desired vehicle longitudinal direction. For example, the positioning signal winding can extend over the entire width of an inductive charging device. Preferably, the positioning signal winding extends over at least 50% of the width of the energy transmission winding of the inductive charging device, particularly preferably over at least 75% of the width of the energy transmission winding of the inductive charging device. In particular, the positioning signal winding can also extend over the entire width of the energy transmission winding of the inductive charging device. In this way, a largely homogeneous magnetic field is created with a main direction of the magnetic flux in the longitudinal direction of the vehicle orThe desired vehicle longitudinal direction is achieved and local field increases are prevented or reduced.

[0031] Advantageously, the positioning signal is generated in the stationary inductive charging device and the voltage signal is induced in the mobile inductive charging device.

[0032] In principle, both inductive charging devices – the stationary and the mobile inductive charging device – can be the inductive charging device in which the positioning signal is generated, and the other of the two inductive charging devices is then the inductive charging device in which the positioning signal is preferably detected by detecting at least one induced voltage signal. However, it can be advantageous to select the stationary inductive charging device as the inductive charging device in which the positioning signal is generated, and thus the mobile inductive charging device as the inductive charging device in which the voltage signal is detected. With this arrangement, the sensor data with the information about directional deviations and relative distances is located directly in the vehicle, which must then also make the appropriate travel correction.If the sensors are located in the stationary inductive charging device, information about a necessary driving correction must first be transmitted to the vehicle. This requires a separate data channel, and delays may occur.

[0033] The approximation expediently involves calculating an approximated relative distance value from the sum of the voltage signals. It is important to note that there is a non-linear relationship between the sum of the voltage signals and the distance value, and the larger the sum of the voltage signals, the smaller the distance value. While the voltage signals from the two sensor windings can be compared to determine a directional deviation, they can be added together to determine a relative distance. The further the two sensor windings are from the transmitter of the positioning signal, the lower the total voltage induced in the two sensor windings, all other parameters being equal. The relationship between distance and induced voltage is non-linear.

[0034] According to a preferred embodiment, the approximate relative distance value is displayed graphically or acoustically in the vehicle. The graphical or acoustic display of the information about the relative distance to the target position can help the driver adjust their speed accordingly and / or prepare for braking. This can be done acoustically, for example, as is already common in parking assistance systems. The information can also be displayed graphically. A graphical display in the form of a bar that decreases as the vehicle approaches the target position can be suitable.

[0035] Particularly preferred is the directional deviation value displayed graphically in the vehicle.

[0036] It is particularly advantageous to display a directional deviation graphically, as a corresponding value is difficult to represent acoustically – perhaps even in addition to acoustic information about the relative distance. The directional deviation value can be represented, for example, in the form of an arrow pointing in the direction in which the driver must steer the vehicle. A corresponding graphical representation can be advantageously realized with a graphic representation of the relative distance – for example, in the form of a decreasing bar.

[0037] Advantageously, a value is calculated from at least the number of turns of the positioning signal winding and the electrical current in the positioning signal winding, and the value is used in the approximation of the relative distance.

[0038] A positioning signal winding through which alternating current flows generates a magnetic flux. This magnetic flux depends, among other parameters, significantly on the number of turns of the positioning signal winding and the electrical current. The effective value of the alternating electrical current is particularly relevant here. The geometry of the positioning signal winding is crucial for the other parameters. For a given frequency and a specific distance, the induced voltage is then proportional to the product of the number of turns and the current. A value calculated at least from the number of turns of the positioning signal winding and the electrical current—in particular, the product of the number of turns and the electrical current—can therefore be used to approximate the relative distance.

[0039] The voltage signals are conveniently converted into digital signals and processed in such a way that only the voltage signals in a specific frequency range are used to determine the sum and the comparison.

[0040] To convert them into digital voltage signals, the signals can be sampled in an analog-to-digital converter. The digital voltage signals can then be transformed into the frequency domain and filtered within a specific frequency range.

[0041] In a frequency transformation, a signal is mathematically transformed from the time domain to the frequency domain. For a time-dependent signal, an analysis in the frequency domain provides information about the intensity of a specific frequency or frequency range in the signal.

[0042] An evaluation in the frequency domain is advantageous here, especially since it is possible to filter the frequency or frequency range of the positioning signal and thus achieve a better signal-to-noise ratio and thus a greater range.

[0043] Alternatively, it may also be possible to evaluate the voltage signal in a specific frequency range or at a specific frequency without performing a mathematical transformation of the entire voltage signal. It is advantageous if the signal transformed into the frequency domain is filtered around the excitation frequency by a filter with a bandwidth B. The generated positioning signal is generated at a specific excitation frequency. The excitation frequency can be in the range from 10 kHz to 150 kHz.

[0044] It is not necessary to evaluate the entire induced voltage signal across the entire frequency range; an evaluation close to the excitation frequency is sufficient. A digital filter can be used for this.

[0045] A digital filter is a mathematical function applied to a discrete signal in the frequency domain. The discrete frequency values ​​are thus restricted to values ​​within a specific preset frequency band with a bandwidth of B. The bandwidth can be, for example, on the order of 1 kHz. The frequency band is selected to contain the excitation frequency; preferably, it should be centered around the excitation frequency.

[0046] In a preferred variant, the calculation of the approximate relative distance value includes a polynomial that is at least a third-degree polynomial. The polynomial can, for example, have the following form: (%) = 0.0000159x 3 - 0.0116395x 2 + 2.9305376%

[0047] Where x can be the measured induced voltage, and f(x) is used to determine the relative distance. A corresponding polynomial is a simple way to approximate the nonlinear relationship between induced voltage and distance.

[0048] [unclaimed]

[0049] In an alternative preferred variant, the calculation of the approximated relative distance value contains an exponential function. Advantageously, the sum of the voltage signals is only evaluated if it exceeds a start value and as long as it does not exceed a stop value. The method for determining a relative distance is advantageous in addition to the determination of a directional deviation, which is based on a comparison of two induced voltages. For a corresponding method, there can be a start value. If the total induced voltage is below this threshold, the signals are too weak to allow optimal evaluation. Furthermore, there can also be a stop value for the induced voltages. If the voltage exceeds this value, the method is no longer sufficiently accurate from this value onwards, and the method is terminated.At short distances and thus high induced voltages, the magnetic field lines exhibit more pronounced curvatures. Therefore, determining a directional deviation from a comparison of different induced voltages at different angles is no longer possible, or at least more difficult, once the distance falls below a certain limit and the induced voltages exceed a certain limit. Beyond this limit and thus beyond this distance, a supplementary near-positioning system must take over.

[0050] The invention further relates to a graphic display element for a vehicle with a mobile inductive charging device, wherein the graphic display element is suitable for displaying a relative distance between a mobile inductive charging device and a stationary inductive charging device as a relative distance indicator and wherein the relative distance is determined by means of a method according to the invention.

[0051] The graphical display element can be a display. The method according to the invention, together with the display element, represents a driver assistance system that supports a driver in precisely positioning themselves in a defined position relative to a stationary inductive charging device. A relative distance indicator can be implemented, for example, in the form of a bar that decreases with decreasing distance to the target position. It is also possible for the graphical display element to additionally visually indicate when the method according to the invention is terminated, and for a supplementary proximity positioning method to be used.

[0052] In addition to the relative distance, a directional deviation can be displayed, for example. A directional deviation can be implemented in the form of an indicator pointing in the direction in which the vehicle must be steered.

[0053] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0054] It shows, schematically

[0055] Fig. 1 is a highly simplified representation of a vehicle with an inductive charging device,

[0056] Fig. 2 is a plan view of an inductive charging device with sensor windings,

[0057] Fig. 3 is a schematic representation of a vehicle charging system during the positioning process,

[0058] Fig. 4 a representation of a graphic display element of the directional deviation a) and four different displays of the relative distance b)-e)

[0059] Fig. 5 is a highly simplified block diagram relating to the evaluation of the measured voltages. Fig. 1 shows a mobile inductive charging device 1, 1a which is arranged on a vehicle 2 with a battery 3 and is positioned above a stationary inductive charging device 1, 1b. During operation, energy can be transferred from the stationary inductive charging device 1b to the mobile inductive charging device 1a, thereby charging the battery 3. The mobile inductive charging device 1a and the stationary inductive charging device 1b together form or are part of the vehicle charging system 8. Energy can be temporarily transferred from the mobile inductive charging device 1a to the stationary inductive charging device 1b.

[0060] The stationary inductive charging device 1b arranged on the ground in Fig. 1 can alternatively be recessed into the roadway (not shown here). In a recessed arrangement, the inductive charging device 1b can be covered by certain layers of the roadway or be flush with the road surface.

[0061] Fig. 2 shows a plan view of an inductive charging device 1 according to the invention. This can be a mobile inductive charging device 1a or a stationary inductive charging device 1b. In the present exemplary embodiment, eight flux guiding elements 5 are shown, which are arranged radially around the center 7 of the energy transmission winding 4 in the plane. The energy transmission winding 4, which is arranged below the flux guiding elements 5 with respect to this plan view, is indicated by dashed lines. The energy transmission winding 4 is here a flat coil 10. A first sensor winding 9a is arranged around one of the flux guiding elements 5, and a second sensor winding 9b is arranged around another flux guiding element 5. The sensor windings are designed here as a cylindrical coil. The first

[0062] Sensor winding 9a is arranged axially symmetrically to the second sensor winding 9b with respect to the vehicle's longitudinal direction 6. The first sensor winding 9a has a first radial longitudinal direction 11a and the second sensor winding 9b has a second radial longitudinal direction 11b. The angle 26 between the first radial longitudinal direction 11a and the vehicle's longitudinal direction 6 is at least approximately the same size as the angle 34 between the second radial longitudinal direction 11b and the longitudinal direction of the vehicle. The first radial longitudinal direction 11a and the second radial longitudinal direction 11b intersect or cross at least approximately in the center 7 of the energy transmission winding 4. The first radial longitudinal direction 11a and the second radial longitudinal direction 11b run radially outwards from the center 7 of the energy transmission winding 4. The two sensor windings 9a, 9b are arranged symmetrically to the vehicle's longitudinal direction 6.

[0063] During the charging process, the vehicle 2 is positioned above the stationary inductive charging device 1b and energy is transferred to the mobile inductive charging device 1a or from the mobile inductive charging device 1a to the stationary inductive charging device 1b. The flux guiding elements 5 assume the function of guiding the magnetic field. In the charging state, the field lines of the magnetic field run approximately radially in them. Three magnetic field lines 35 are symbolically indicated in Fig. 2. Since the first radial longitudinal direction 11a and the second radial longitudinal direction 11b are also aligned radially and thus at least approximately parallel to the magnetic field lines 35, only relatively little or no voltage is induced in the first sensor winding 9a and the second sensor winding 9b.This is important because the high power levels of the energy transfer could otherwise easily lead to the destruction of the sensor windings.

[0064] Fig. 3 a) shows a vehicle 2 with a vehicle longitudinal direction 6 with a mobile inductive charging device 1a during a positioning process above a stationary inductive charging device 1b with a target vehicle longitudinal direction 6a. The vehicle 2 drives directly towards the stationary inductive charging device 1b and the target vehicle longitudinal direction 6a is thus the same as the longitudinal direction of the vehicle 6. In addition to the energy transmission winding (not shown), the mobile inductive charging device 1a also contains a positioning signal winding 41. The positioning signal winding 41 has a winding axis 36 and a radial longitudinal direction 11. The stationary inductive charging device 1b has two sensor windings 9a and 9b in addition to the energy transmission winding (not shown). In contrast to the embodiment in Fig. 2, the two sensor windings 9a and 9b here have a greater extension and cross in the middle of the inductive charging device 1.Both sensor windings 9a and 9b each have a radial longitudinal direction 11a and 11b. Both sensor windings 9a and 9b are arranged symmetrically to the desired vehicle longitudinal direction 6a. This arrangement of the windings is particularly advantageous for positioning. The positioning signal winding 41 generates a positioning signal (not shown) which can induce a voltage in the sensor windings 9a and 9b. The positioning signal winding 41 generates a fairly homogeneous magnetic field. A voltage is induced in the sensor windings 9a and 9b by the magnetic field of the positioning signal winding 41. If the vehicle drives exactly perpendicularly towards the stationary inductive charging device 1b, as shown in the left-hand sketch, an equal voltage is induced in both sensor windings 9a and 9b.

[0065] Fig. 3 b) shows an embodiment in which the positioning signal winding 41 is arranged in the stationary inductive charging device 1 b and the sensor windings 9a and 9b are arranged in the mobile inductive charging device 1a. The functioning of this embodiment is otherwise exactly the same. Shown here is a case in which the vehicle 2 does not drive perpendicularly towards the stationary inductive charging device 1 b, but deviates from it at an angle of approximately 45°. The vehicle's longitudinal direction 6 and the connecting line between the stationary inductive charging device 1 b and the mobile inductive charging device 1a are thus at a directional deviation angle 39 of 45°. In this case, the positioning signal winding 41 generates a magnetic field which is perpendicular to the first sensor winding 9a. Here, a maximum voltage is induced.The magnetic field generated by the positioning signal winding 41 is also approximately parallel to the second sensor winding 9b. Minimal or no voltage is induced here.

[0066] In both embodiments Fig. 3a) and 3b), in addition to determining a directional deviation value by comparing the voltages induced in the two sensor windings 9a and 9b, a distance value to the target position can be approximated from the sum of the voltages induced in the two sensor windings 9a and 9b.

[0067] Fig. 4 shows a representation of a graphic display element 50 which displays the directional deviation a) as well as the relative distance at four different distances b)-e). In a), an arrow can be seen as a directional deviation indicator 47 on a graphic display element 50. The graphic display element 50 is located in a vehicle. In Figs. 4b) to 4e), a relative distance indicator 48 in the form of a bar is shown in a graphic display element 50 during an approach process. The bar slowly decreases from Fig. 4b) via Fig. 4c) and Fig. 4d) to Fig. 4e) as the vehicle approaches its target position. The graphic display element 50 also shows a near positioning circle 49. As soon as the distance indicator 48 in the form of a bar has deteriorated to such an extent that it is located within the near positioning circle 49, the positioning method that is evaluated changes.Within the near-positioning circle 49, a so-called near-positioning method is evaluated. This provides direct information about the relative distance to the target position, but no longer provides a direct directional deviation value.

[0068] Fig. 5 shows a highly simplified block diagram of the evaluation of the measured voltages. The voltage signals 13a, 13b received in the two sensor signal windings 9a, 9b are both processed in a comparison unit COMP and a summation unit SUM. The comparison unit COMP compares the two voltage signals 13a, 13b with each other and determines a directional deviation value 17. This directional deviation value is displayed in a graphic display element 50 as a directional deviation indicator 47 in the form of an arrow. The summation unit SUM adds the two voltage signals 13a, 13b. The result 43 is displayed in a graphic display element 50 as a relative distance indicator 48 in the form of a bar. In a test unit CHECK it is checked whether the sum of the voltage signals 13a, 13b is above a start value of the voltage signals 45 and below a stop value of the voltage signals 46.Only if both are true is the result displayed in the graphic display element 50. The graphic display element 50 further contains a near positioning circle 49. If the sum of the voltage signals 13a, 13b corresponds to the stop value of the voltage signals 46, the graphic display element 50 shows the relative distance indicator 48 in the form of a bar precisely on the near positioning circle 49. If the sum of the voltage signals 13a, 13b is greater than the stop value of the voltage signals 46, the positioning method according to the invention is no longer evaluated for the graphic display element 50. Another near positioning method is now evaluated and displayed on the graphic display element 50.

[0069] Reference symbol

[0070] 1 inductive charging device

[0071] 1a mobile inductive charging device

[0072] 1 b stationary inductive charging device

[0073] 2 vehicles

[0074] 3 Vehicle energy storage

[0075] 4 Energy transmission winding

[0076] 5 Flow guide element

[0077] 6 Vehicle longitudinal direction

[0078] 6a Target vehicle longitudinal direction

[0079] 7 Center of the energy transmission winding

[0080] 8 Vehicle charging system

[0081] 9 Sensor winding

[0082] 9a first sensor winding

[0083] 9b second sensor winding

[0084] 10 flat coil

[0085] 11 radial longitudinal direction

[0086] 11 a first radial longitudinal direction

[0087] 11 b second radial longitudinal direction

[0088] 13 Voltage signal

[0089] 13a first voltage signal

[0090] 13b second voltage signal

[0091] 17 Directional deviation value

[0092] 32 Gap between flow guide elements

[0093] 33 first angle

[0094] 34 second angle

[0095] 35 Magnetic field line

[0096] 36 Winding axis

[0097] 39 Direction deviation angle 41 Positioning signal winding

[0098] 43 Sum of voltage signals

[0099] 44 Approximate relative distance value

[0100] 45 Starting value of the voltage signals

[0101] 46 Stop value of the voltage signals

[0102] 47 Direction deviation indicator

[0103] 48 Relative distance indicators

[0104] 49 Near positioning circle

[0105] 50 graphic display element

[0106] COMP comparison unit

[0107] SUM summation unit

[0108] CHECK test unit

Claims

Claims Method for positioning a vehicle (2) with a mobile inductive charging device (1a) in a defined position relative to a stationary inductive charging device (1b), wherein - a positioning signal is generated in one of the two inductive charging devices (1a, 1b) and - the positioning signal induces at least one voltage signal (13a, 13b) in the other of the two inductive charging devices (1a, 1b) - a relative distance between the mobile inductive charging device (1a) and the stationary inductive charging device (1b) is approximated from the induced voltage signal (13a, 13b). Method according to claim 1, wherein - the mobile inductive charging device (1a) or the stationary inductive charging device (1b) has a first sensor winding (9a) and a second sensor winding (9b) which are arranged symmetrically to the vehicle longitudinal direction (6) or to the desired vehicle longitudinal direction (6a), - the positioning signal generates a first voltage signal (13a) in the first sensor winding (9a) and a second voltage signal (13b) in the second sensor winding (9b), - an approximate relative distance value (44) is determined from the sum of the two voltage signals (43) and - a directional deviation value (17) between the vehicle longitudinal direction (6) and the desired vehicle longitudinal direction (6a) is determined from the comparison of the two voltage signals (13a, 13b) with each other. Method according to claim 1 or claim 2, wherein the positioning signal is generated by a positioning signal winding (41) with a winding axis in the vehicle longitudinal direction (6) or desired vehicle longitudinal direction (6a). Method according to one of the preceding claims, wherein the positioning signal (41) is generated in the stationary inductive charging device (1b) and the voltage signal is induced in the mobile inductive charging device (1a). Method according to one of the preceding claims, wherein the approximation - a calculation of an approximate relative distance value (44) from the sum of the voltage signals (43) - where the following applies to the calculation: • there is a non-linear relationship between the sum of the voltage signals (43) and the distance value (44), • the distance value (44) is smaller the larger the sum of the voltage signals (43). Method according to one of the preceding claims, characterized in that the approximated relative distance value (44) is displayed graphically or acoustically in the vehicle. Method according to one of the preceding claims, characterized in that the directional deviation value (17) is displayed graphically in the vehicle. Method according to one of claims 3-7, characterized in that - a value is calculated from at least the number of turns of the positioning signal winding (41) and the electrical current intensity in the positioning signal winding (41), and - the value is used in the approximation of the relative distance. Method according to one of the preceding claims, wherein the voltage signals (13a, 13b) are converted into digital signals and processed such that only the voltage signals in a specific frequency range are used for determining the sum (43) and the comparison. Method according to one of claims 5-9, characterized in that the calculation of the approximated relative distance value (44) contains a polynomial which is a polynomial of at least third degree. Method according to one of the preceding claims, characterized in that the sum of the voltage signals (43) is only evaluated if it exceeds a start value (45) and as long as it does not exceed a stop value (46).Graphic display element (50) for a vehicle (2) with a mobile inductive charging device (1a), wherein the graphic display element (50) is suitable for displaying a relative distance between a mobile inductive charging device (1a) and a stationary inductive charging device (1b) as a relative distance indicator (48) and the relative distance is determined by means of a method according to one of claims 1-11.

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