Method for locating vehicle

Abstract

The invention relates to a method for positioning a vehicle (2) having a mobile inductive charging device (1a) in a defined position relative 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). The relative distance between the mobile inductive charging device (1a) and the stationary inductive charging device (1b) is approximated from the induced voltage signals (13a, 13b).

Description

Technical Field

[0001] The invention relates to a method for locating a vehicle according to the generic nature of the independent claims. Furthermore, the invention relates to a graphical display element for a vehicle. Background Art

[0002] US Pat. No. 10,541,551 B2 proposes guiding a vehicle to a location defined by an x-value and a y-value by means of an evaluation of the magnitude of the induced voltage. However, this method involves relatively complex calculations. Summary of the invention

[0003] The present invention is based on the object of specifying an improved or at least alternative embodiment for a method of the type mentioned in the introduction for locating a vehicle.

[0004] In the present case, a method is proposed for positioning a vehicle having 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, the positioning signal inducing 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.

[0005] The term "inductive charging device" therefore refers here only to one of the at least two parts which is necessary for the inductive charging process for energy transfer. During the inductive charging process, the energy transfer winding generates an alternating magnetic field in the inductive charging device during the energy transfer. This alternating magnetic field induces a voltage in the further energy transfer winding of the further inductive charging device. Thus, for this specific charging process, the further inductive charging device serves as a counterpart. Energy is transmitted wirelessly and received by inducing a voltage.

[0006] A stationary inductive charger is the non-mobile part of a vehicle's charging system, ie the part that does not move with the vehicle.

[0007] Preferably, the stationary inductive charging device can be located on, at or in the ground. This can be an inductive charging device applied to a base or an inductive charging device sunk into a base or into the ground. The ground can be a driveway, a parking lot surface, a garage floor, a floor in a parking garage or other building. However, as an alternative, the stationary inductive charging device can also be located on a wall or the like.

[0008] The mobile inductive charging device can be arranged on and / or in the vehicle. Quite generally, this is understood to be a part of the vehicle charging system that moves with the vehicle. Thus, an inductive charging device on and / or in the vehicle is suitable for receiving a magnetic field and providing electrical energy from an energy store of the vehicle, for example a battery or accumulator in the vehicle.

[0009] For efficient energy transmission, it is necessary to position the mobile inductive charging device as accurately as possible relative to the stationary inductive charging device. That is, the mobile inductive charging device needs to be positioned in a defined position relative to the stationary inductive charging device. The defined position is a predetermined position, in the case of which it is preferably taken into account that the energy transmission can take place with the highest possible efficiency. In this case, it can be taken into account in particular that each of the energy transmission windings in the two inductive charging devices is positioned in a manner with the smallest possible spacing between each other and in a manner opposite to each other with respect to the air gap between them. Since the two energy transmission windings generally do not have to be of the same size, symmetrical positioning is also advantageous in this case, in which the winding axes of the two energy transmission windings overlap as much as possible. Usually, for the driver, accurate positioning is difficult or impossible without additional support in the form of a driver assistance system.

[0010] Here, the locating signal may be an alternating electromagnetic field or an alternating magnetic field, which may induce a voltage signal in the other of the two inductive charging devices. It is possible that the locating signal is directly emitted or generated by the energy transmission winding of the inductive charging device, or that one or more additional windings or other signal generating devices are present for this purpose.

[0011] Preferably, the locating signal transmits a power which is significantly lower than the power transmitted during the energy transmission.

[0012] If a locating signal is generated in the stationary inductive charging device, the locating signal induces a voltage in the mobile inductive charging device. If a locating signal is generated in the mobile inductive charging device, the locating signal induces a voltage in the stationary inductive charging device.

[0013] A corresponding inductive charging device can be a larger structural unit, wherein the structural elements for energy transmission only occupy a part of the inductive charging device. Generating a positioning signal "in" the inductive charging device or generating a voltage signal "in" the inductive charging device means that this occurs within the larger structural unit.

[0014] During the positioning process, it is important for the driver of the vehicle that the driver obtains information about the relative distance to the target position. Like this, the driver can gradually adjust the speed or prepare for the braking process accordingly.

[0015] Relative distance refers to the following parameter: if the distance changes, the parameter changes continuously, preferably proportionally with the distance, but the parameter does not necessarily provide a statement about the absolute distance in meters. During the positioning process, it is sufficient for the driver to obtain information about the relative distance to the target position, for example via a graphic display element. Here, information about the absolute distance is not necessary. Other relative methods are based on the comparison of multiple signals, and the magnitude of the induced voltage is used as the basis for determining the relative distance. Then, the relative distance is approximated from the induced voltage. This means that the measured induced voltage is included in the calculation based on at least part of the approximation. For example, this can be a polynomial approximation, which approximates the nonlinear ratio between the voltage induced by the alternating magnetic field and the distance from the transmitter of the magnetic field. In general, the approximate determination of the absolute distance in meters requires a laborious calibration. The combination of approximate calculation and the only relative determination of the distance is advantageous because it is a simple possibility to provide the driver with necessary information without expensive calibration.

[0016] Preferably, the mobile inductive charging device or the stationary inductive charging device has a first sensor winding and a second sensor winding, the first sensor winding and the second sensor winding are arranged symmetrically with respect to the longitudinal direction of the vehicle or with respect to the longitudinal direction of the target vehicle, the positioning signal generates a first voltage signal in the first sensor winding and a second voltage signal in the second sensor winding, an approximate relative distance value is determined from the sum of the two voltage signals, and a directional deviation value between the longitudinal direction of the vehicle and the longitudinal direction of the target vehicle is determined from a comparison of the two voltage signals.

[0017] The first and / or the second sensor winding may be arranged in or on a mobile or stationary inductive charging device.

[0018] In general, a coil is defined as a component for generating or receiving a magnetic field. A coil can consist of a winding and optional further 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 windings, wherein one winding represents a complete revolution of the conductor. However, in general, a winding can also consist of only less than one winding, i.e., for example, 0.5 windings. Of course, a non-integer number of windings, such as 2.5 windings, is also possible.

[0019] The sensor winding according to the invention can be implemented in different forms and can have a half winding, a winding or preferably a plurality of windings. For example, the conductor of such a sensor winding can have a thickness of 0.01 mm. 2 With 2mm 2 The conductor can be designed as a stranded wire, as a single conductor or in another form, for example in the form of a conductor track on a printed circuit board.

[0020] If the sensor winding is located in a mobile inductive charging device, it is oriented symmetrically with respect to the longitudinal direction of the vehicle. If the sensor winding is located in a stationary inductive charging device, it is oriented symmetrically with respect to the longitudinal direction of the target vehicle.

[0021] The stationary inductive charging device has a target vehicle longitudinal direction, which is the direction in which the longitudinal direction of the vehicle should lie after a successful positioning process.

[0022] The symmetrical arrangement of the two sensor windings with respect to the longitudinal direction of the vehicle or with respect to the longitudinal direction of the target vehicle means that the angle between the first sensor winding and the longitudinal direction of the vehicle / the longitudinal direction of the target vehicle is at least approximately equal to the angle between the second sensor winding and the longitudinal direction of the vehicle / the longitudinal direction of the target vehicle, wherein the two sensor windings are arranged axially symmetrically in the longitudinal direction of the vehicle / the longitudinal direction of the target vehicle in a mirror-image manner. The symmetrical arrangement is advantageous because here - in addition to the relative distance - the direction deviation can also be determined by simply comparing the voltages induced in the two sensor windings. For example, the two sensor windings can be arranged at an angle of 45° with respect to the longitudinal direction of the vehicle or with respect to the longitudinal direction of the target vehicle. The positioning signal can be symmetrical with respect to the longitudinal direction of the vehicle or with respect to the longitudinal direction of the target vehicle. In particular, the positioning signal can have a main direction of the magnetic field in the longitudinal direction of the vehicle or in the longitudinal direction of the target vehicle.

[0023] Advantageously, the locating signal is generated by a locating signal winding having a winding axis in the longitudinal direction of the vehicle or in the longitudinal direction of the target vehicle.

[0024] If the locating signal winding is located in a mobile inductive charging device of a vehicle, the winding axis of the locating signal winding is advantageously oriented in the longitudinal direction of the vehicle.

[0025] If the locating signal winding is located in a stationary inductive charging device, the winding axis of the locating signal winding is advantageously oriented in the longitudinal direction of the target vehicle.

[0026] Such an arrangement generates a magnetic field with a main direction of the magnetic field lines in the longitudinal direction of the vehicle or in the longitudinal direction of the target vehicle. This has the advantage that, with the same power or the same magnetic field strength, this embodiment achieves a significantly larger range for positioning than with the help of a positioning signal generated by an energy transmission winding. In addition, such an orientation of the magnetic field is also particularly well suited for realizing the simplest possible detection of positional or angular deviations in the sensor winding.

[0027] The positioning signal winding can be implemented as a solenoid coil, which is also called a cylindrical coil.

[0028] Particularly preferably, the locating signal winding is constructed in such a way that it has a particularly large extension in the driving plane and perpendicular to the longitudinal direction of the vehicle or perpendicular to the longitudinal direction of the target vehicle. For example, the locating signal winding can extend over the entire width of the inductive charging device. Preferably, the locating 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 locating signal winding can also extend over the entire width of the energy transmission winding of the inductive charging device. Thus, a largely uniform magnetic field is achieved, which has a main direction of the magnetic flux in the longitudinal direction of the vehicle or the longitudinal direction of the target vehicle, and local field increases are prevented or reduced.

[0029] Advantageously, the positioning signal is generated in the stationary inductive charging device and the voltage signal is induced in the mobile inductive charging device.

[0030] In principle, both inductive charging devices, both a stationary and a mobile inductive charging device, can be inductive charging devices in which a positioning signal is generated, and then the respective other of the two inductive charging devices is an inductive charging device in which the positioning signal is detected, preferably by detecting at least one induced voltage signal. However, it can be advantageous to select the stationary inductive charging device as an inductive charging device in which a positioning signal is generated, and therefore the mobile inductive charging device as an inductive charging device in which a voltage signal is detected. In this arrangement, the sensor data with information about the direction deviation and the relative distance are directly in the vehicle, which then also needs to make corresponding driving corrections. If the sensor device is located in the stationary inductive charging device, then the corresponding information about the necessary driving correction needs to be transmitted to the vehicle first. For this purpose, a separate data channel is required and time delays may occur.

[0031] Advantageously, the approximation comprises calculating an approximate relative distance value from the sum of the voltage signals, wherein it applies to the calculation that a nonlinear relationship exists 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.

[0032] To determine the directional deviation, the voltage signals from the two sensor windings can be compared with each other, and to determine the relative distance, these voltage signals can be added. If the parameters are otherwise the same, the farther the two sensor windings are from the transmitter of the positioning signal, the smaller the voltage induced into the two sensor windings in terms of φ and φ. Here, the relationship between distance and induced voltage is nonlinear.

[0033] According to a preferred specific embodiment, the approximate relative distance value is displayed graphically or acoustically in the vehicle.

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

[0035] Particularly preferably, the direction deviation value is displayed graphically in the vehicle.

[0036] Particularly advantageously, the direction deviation can be displayed graphically, since the corresponding value can only be represented acoustically with difficulty, possibly even apart from the acoustic information about the relative distance. In this case, the direction deviation value can be realized, for example, in the form of an arrow pointing in the direction in which the driver needs to steer the vehicle. Advantageously, the corresponding graphical representation can be realized by means of a graphical representation of the relative distance, for example in the form of a decreasing bar.

[0037] Advantageously, a value is calculated from the number of turns of the locating signal winding and the current intensity in the locating signal winding, which value is used when approximating the relative distance.

[0038] The locating signal winding through which the alternating current flows generates a magnetic flux. In addition to other parameters, this magnetic flux is significantly related to the number of turns of the locating signal winding and the current intensity. In particular, the effective value of the alternating current is of great relevance here. Among other parameters, it is mainly the geometry of the locating signal winding that is critical. Then, for a given frequency and a determined distance, the induced voltage is proportional to the product consisting of the number of turns and the current intensity. Therefore, at least the value calculated from the number of turns and the current intensity of the locating signal winding, that is, in particular the product consisting of the number of turns and the current intensity, can be used to approximate the relative distance.

[0039] The voltage signal is expediently converted into a digital signal and processed in such a way that only the voltage signal in a specific frequency range is used for the determination and comparison.

[0040] For conversion into a digital voltage signal, the signal can be sampled in an analog-to-digital conversion unit. The digital voltage signal can then be transformed into the frequency range and filtered in a specific frequency range.

[0041] In frequency conversion, the signal is mathematically transformed from the time domain into the frequency range. For time-dependent signals, evaluation in the frequency range shows how strongly certain frequencies or certain frequency ranges are present in the signal.

[0042] Evaluation in the frequency range is advantageous in this case, in particular because the frequencies or frequency ranges of the locating signal can thereby be filtered and thus a better signal-to-noise ratio and thus a greater range can be achieved.

[0043] Alternatively, it may also be possible to evaluate the voltage signal in a certain frequency range or at a certain frequency without having to carry out a mathematical transformation of the entire voltage signal for this purpose.

[0044] Advantageously, the signal converted into the frequency range is filtered by a filter having a bandwidth B around the excitation frequency. The generated locating signal is generated at a certain excitation frequency. The excitation frequency can be in the range of 10 kHz to 150 kHz.

[0045] It is not necessary to evaluate the complete induced voltage signal in the entire frequency range, but rather it is sufficient to evaluate it in the vicinity of the excitation frequency. For this purpose, a digital filter can be used.

[0046] A digital filter is a mathematical function applied to a discrete signal in this frequency range. The discrete frequency values ​​are thus limited to values ​​in a certain pre-set frequency band with a bandwidth B. For example, the bandwidth may be in the order of magnitude of 1 kHz. The frequency band is selected such that it contains the excitation frequency, advantageously such that it contains the excitation frequency centrally.

[0047] In a preferred variant, the calculation of the approximate relative distance value includes a polynomial, which is at least a cubic polynomial. For example, the polynomial can have the following form:

[0048] f(x)=0.0000159x 3 -0.0116395x 2 +2.9305376x

[0049] In this case, x can be the measured induced voltage, and f(x) is included in the determination of the relative distance or is the relative distance. A corresponding polynomial is a simple possibility for approximating the nonlinear dependence between the induced voltage and the distance.

[0050] [No protection claimed]

[0051] In an alternative preferred variant, the calculation of the approximate relative distance value involves an exponential function.

[0052] Advantageously, the sum of the voltage signals is analyzed only when it is greater than the starting value and as long as it is not greater than the stop value. Advantageously, the method for determining the relative distance is a supplement to the determination of the directional deviation, which is based on the comparison of two induced voltages. For the corresponding method, a starting value may exist. If the induced voltage is less than the threshold value in terms of sum, the signal is too weak to achieve the best analysis. However, in addition, a stop value for the induced voltage may also exist. If the voltage is greater than this value, the method is no longer sufficiently accurate from this value and the method is terminated. In the case of a small distance and therefore a high induced voltage, the magnetic field lines have a strong curvature. Therefore, from less than a distance, and therefore from greater than the stop value for the induced voltage, it may no longer be possible or at least more difficult to achieve the corresponding determination of the directional deviation from the comparison of different induced voltages at different angles. Then, from this stop value, and therefore from this distance, the short-range positioning system that supplements needs to take over.

[0053] The invention further relates to a graphical display element for a vehicle having a mobile inductive charger, wherein the graphical display element is suitable for displaying a relative distance between the mobile inductive charger and a stationary inductive charger as a relative distance indicator, and wherein the relative distance is determined by means of the method according to the invention.

[0054] The graphic display element can be a display. Together with the display element, the method according to the invention forms a driver assistance system which supports the driver in accurately positioning the vehicle in a defined position relative to the stationary inductive charging device. For example, the relative distance indicator can be implemented in the form of a bar which decreases as the distance to the target position decreases. It is also possible that the graphic display element additionally visually indicates when the method according to the invention has been terminated and a supplementary close-range positioning method is used.

[0055] In addition to the relative distance, the direction deviation can be displayed, for example. The direction deviation can be implemented in the form of a pointer, which points to the direction in which the vehicle needs to be turned. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar components or components having the same function.

[0057] The accompanying drawings schematically show:

[0058] Figure 1 shows a greatly simplified schematic diagram of a vehicle with an inductive charging device,

[0059] Figure 2 shows a top view of an inductive charging device with a sensor winding,

[0060] Figure 3 A schematic diagram showing a vehicle charging system during a positioning process,

[0061] Figure 4 Schematic diagram of a graphic display element showing a) directional deviation and four different readings b)-e) of relative distance

[0062] Figure 5 A greatly simplified block diagram is shown with regard to the evaluation of the measured voltage. DETAILED DESCRIPTION

[0063] Figure 1The figure shows mobile inductive charging device 1, 1a, which is arranged on vehicle 2 with battery 3 and is positioned above stationary inductive charging device 1, 1b. During operation, energy can be transferred from stationary inductive charging device 1b to mobile inductive charging device 1a, and battery 3 can be charged thereby. Mobile inductive charging device 1a and stationary inductive charging device 1b together form vehicle charging system 8 or are part of vehicle charging system 8. In this case, energy can be temporarily transferred from mobile inductive charging device 1a to stationary inductive charging device 1b.

[0064] Alternatively, in Figure 1 The stationary inductive charging device 1b arranged on a base in the embodiment can also be arranged in a manner sunken in the roadway (not shown here). In the case of a sunken arrangement, the inductive charging device 1b can be covered by a certain layer of the roadway, or it can be flush with the roadway surface.

[0065] Figure 2 A top view of an inductive charging device 1 according to the invention is shown. 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 in a plane radially around the center 7 of the energy transmission winding 4. The energy transmission winding 4 arranged below the flux guiding element 5 is indicated by a dashed line in this top view. The energy transmission winding 4 is a flat coil 10 here. A first sensor winding 9a is arranged around one of the flux guiding elements 5 and a second sensor winding 9b is arranged around the other flux guiding element 5. In this case, the sensor windings are designed as cylindrical coils. The first sensor winding 9a is arranged axially symmetrically with respect to the second sensor winding 9b with respect to the longitudinal direction 6 of the vehicle. 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 longitudinal direction 6 of the vehicle and the angle 34 between the second radial longitudinal direction 11b and the longitudinal direction of the vehicle are at least approximately the same size. 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 extend radially outwards from the center 7 of the energy transmission winding 4. The two sensor windings 9a, 9b are arranged symmetrically with respect to the vehicle longitudinal direction 6.

[0066] During the charging process, vehicle 2 is positioned above stationary inductive charging device 1b and energy is transferred to mobile inductive charging device 1a or from mobile inductive charging device 1a to stationary inductive charging device 1b. In this process, flux guidance element 5 assumes the function of magnetic field guidance. In the charging state, the field lines of the magnetic field extend approximately in the radial direction in the flux guidance element. Figure 2 , three magnetic field lines 35 are indicated symbolically. Since the first radial longitudinal direction 11a and the second radial longitudinal direction 11b are also oriented radially and therefore at least approximately parallel to the magnetic field lines 35, only relatively small voltages or even no voltages are induced in the first sensor winding 9a and the second sensor winding 9b. This is important because otherwise the sensor windings could easily be damaged in the case of high powers of energy transmission.

[0067] Figure 3 a) shows a vehicle 2 with a vehicle longitudinal direction 6 during a positioning process above a stationary inductive charging device 1b, which has a mobile inductive charging device 1a, which has a target vehicle longitudinal direction 6a. Vehicle 2 is traveling directly towards stationary inductive charging device 1b, so that target vehicle longitudinal direction 6a is identical to the longitudinal direction 6 of the vehicle. In addition to the energy transmission winding (not shown), a positioning signal winding 41 is also located in the mobile inductive charging device 1a. Positioning signal winding 41 has a winding axis 36 and a radial longitudinal direction 11. In addition to the energy transmission winding (not shown), the stationary inductive charging device 1b has two sensor windings 9a and 9b. With Figure 2 Unlike the embodiment in , the two sensor windings 9a and 9b have a larger extension here and cross in the center of the inductive charging device 1. The two sensor windings 9a and 9b each have a radial longitudinal direction 11a and 11b. The two sensor windings 9a and 9b are arranged symmetrically with respect to the longitudinal direction 6a of the target vehicle. This arrangement of windings for positioning is particularly advantageous. 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 relatively uniform magnetic field. In the sensor windings 9a and 9b, a voltage is induced by the magnetic field of the positioning signal winding 41. If the vehicle is traveling exactly vertically toward the fixed inductive charging device 1b as shown in the left figure, voltages of the same magnitude are induced in the two sensor windings 9a and 9b.

[0068] Figure 3b) shows the following embodiment: In this embodiment, the locating signal winding 41 is arranged in the stationary inductive charging device 1b, and the sensor windings 9a and 9b are arranged in the mobile inductive charging device 1a. In other respects, the working principle of this embodiment is exactly the same. Here, the following situation is shown: In this case, the vehicle 2 does not travel perpendicularly to the stationary inductive charging device 1b, but deviates from the stationary inductive charging device at an angle of approximately 45°. Therefore, the longitudinal direction 6 of the vehicle and the connecting line between the stationary inductive charging device 1b and the mobile inductive charging device 1a are at a directional deviation angle 39 of 45° to each other. In this case, the locating signal winding 41 generates a magnetic field perpendicular to the first sensor winding 9a. In this case, the maximum voltage is induced. In addition, the magnetic field generated by the locating signal winding 41 is approximately parallel to the second sensor winding 9b. In this case, the minimum voltage or no voltage is induced.

[0069] exist Figure 3 a) and Figure 3 In the two embodiments of b), in addition to determining the direction deviation value by comparing the voltages sensed in the two sensor windings 9a and 9b, the distance value to the target position can also be approximated by the sum of the voltages sensed in the two sensor windings 9a and 9b.

[0070] Figure 4 A schematic diagram of a graphic display element 50 is shown which displays a directional deviation a) and a relative distance b)-e) at four different distances. In a), an arrow can be seen as a directional deviation indicator 47 on the graphic display element 50. The graphic display element 50 is located in the vehicle. Figure 4 b) to 4e) show a relative distance indicator 48 in the form of a bar in the graphic display element 50 during the approach process. As the vehicle gets closer to its target position, the bar changes from Figure 4 b) Via Figure 4 c) and Figure 4 d) Until Figure 4 e) slowly decreases. In addition, the graphic display element 50 shows a close-range positioning circle 49. If the distance indicator 48 in the form of a bar is reduced until it is within the close-range positioning circle 49, the evaluated positioning method changes. Within the close-range positioning circle 49, the so-called close-range positioning method is evaluated. This directly provides a statement about the relative distance to the target position, but no longer provides a direct direction deviation value.

[0071] Figure 5A greatly simplified block diagram is shown in connection with the evaluation of the measured voltage. The voltage signals 13a, 13b received in the two sensor signal windings 9a, 9b are processed not only in the comparison unit COMP but also in the summing unit SUM. The comparison unit COMP compares the two voltage signals 13a, 13b with one another and determines a direction deviation value 17, which is displayed in the graphic display element 50 as a direction deviation indicator 47 in the form of an arrow. The summing unit SUM adds the two voltage signals 13a, 13b, the result 43 being displayed in the graphic display element 50 as a relative distance indicator 48 in the form of a bar. In the test unit CHECK, it is checked whether the sum of the voltage signals 13a, 13b is greater than the start value 45 of the voltage signal and less than the stop value 46 of the voltage signal. The result is displayed in the graphic display element 50 only if both conditions exist. In addition, the graphic display element 50 contains a close-range positioning circle 49. If the sum of the voltage signals 13a, 13b corresponds to the stop value 46 of the voltage signal, the graphic display element 50 shows the relative distance indicator 48 in the form of a bar exactly on the close-range locating circle 49. If the sum of the voltage signals 13a, 13b is greater than the stop value 46 of the voltage signal, the locating method according to the invention is no longer evaluated for the graphic display element 50. A further close-range locating method is now evaluated and displayed on the graphic display element 50.

[0072] Reference numerals list

[0073] 1 Inductive charging device

[0074] 1a Mobile inductive charging device

[0075] 1b Fixed inductive charging device

[0076] 2 Vehicles

[0077] 3. Vehicle energy storage

[0078] 4 Energy transfer winding

[0079] 5 Magnetic flux guiding elements

[0080] 6 Vehicle longitudinal direction

[0081] 6a Target vehicle longitudinal direction

[0082] 7 Center of the energy transfer winding

[0083] 8 Vehicle Charging System

[0084] 9 Sensor winding

[0085] 9a First sensor winding

[0086] 9b Second sensor winding

[0087] 10 Flat Coil

[0088] 11 Radial longitudinal direction

[0089] 11a First radial longitudinal direction

[0090] 11b Second radial longitudinal direction

[0091] 13 Voltage signal

[0092] 13a First voltage signal

[0093] 13b Second voltage signal

[0094] 17 Direction deviation value

[0095] 32 Gap between flux guiding elements

[0096] 33 First Angle

[0097] 34 Second Angle

[0098] 35 Magnetic Field Lines

[0099] 36 Winding axis

[0100] 39 Direction deviation angle

[0101] 41 Positioning signal winding

[0102] 43 Sum of voltage signals

[0103] 44 Approximate relative distance value

[0104] 45 Starting value of voltage signal

[0105] 46 Stop value of voltage signal

[0106] 47 Direction deviation indicator

[0107] 48 Relative distance indicator

[0108] 49 Close-range positioning circle

[0109] 50 Graphic display components

[0110] COMP comparison unit

[0111] SUM summation unit

[0112] CHECK inspection unit

Claims

1. A method for positioning a vehicle (2) having a mobile inductive charging device (1a) in a defined position relative to a stationary inductive charging device (1b), wherein: generating a positioning signal 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), The relative distance between the mobile inductive charging device (1a) and the fixed inductive charging device (1b) is approximated from the induced voltage signals (13a, 13b).

2. The 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), wherein the first sensor winding and the second sensor winding are arranged symmetrically with respect to the longitudinal direction (6) of the vehicle or with respect to the longitudinal direction (6a) of the target vehicle, 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), determining an approximate relative distance value (44) from the sum (43) of the two voltage signals, A direction deviation value (17) between the vehicle longitudinal direction (6) and a target vehicle longitudinal direction (6a) is determined from a comparison of the two voltage signals (13a, 13b) with one another.

3. The method according to claim 1 or claim 2, wherein: The positioning signal is generated by a positioning signal winding (41), which has a winding axis in the longitudinal direction (6) of the vehicle or in the longitudinal direction (6a) of the target vehicle.

4. A method according to any one of the preceding claims, wherein: The positioning signal (41) is generated in the fixed inductive charging device (1b), and the voltage signal is induced in the mobile inductive charging device (1a).

5. A method according to any one of the preceding claims, wherein: The approximation includes Calculate an approximate relative distance value (44) from the sum (43) of the voltage signals Among them, the following are applicable to the calculation: There is a nonlinear relationship between the sum (43) of the voltage signals and the distance value (44), The greater the sum (43) of the voltage signals is, the smaller the distance value (44) is.

6. The method according to any one of the preceding claims, characterized in that The approximate relative distance value (44) is displayed graphically or acoustically in the vehicle.

7. The method according to any one of the preceding claims, characterized in that The direction deviation value (17) is displayed graphically in the vehicle.

8. The method according to any one of claims 3 to 7, characterized in that: calculating a value from at least the number of turns of the positioning signal winding (41) and the current intensity in the positioning signal winding (41), This value is used when approximating the relative distance.

9. A method according to any one of the preceding claims, wherein: The voltage signals (13a, 13b) are converted into digital signals and processed in such a way that only voltage signals in a specific frequency range are used to determine the sum (43) and the comparison.

10. The method according to any one of claims 5 to 9, characterized in that: The calculation of the approximate relative distance value (44) involves a polynomial, which is at least a cubic polynomial.

11. The method according to any one of the preceding claims, characterized in that The sum (43) of the voltage signals is evaluated only if the sum of the voltage signals is greater than a start value (45) and as long as the sum of the voltage signals is not greater than a stop value (46).

12. A graphical display element (50) for a vehicle (2) having 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 for determining the relative distance by means of a method according to any one of claims 1 to 11.

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