WO2024038061A1 - Inductive charging device for a vehicle charging system - Google Patents

Abstract

The invention relates to an inductive charging device (1, 1a) for a vehicle charging system (8), comprising an energy transmission winding and at least one flux-guiding element and at least one first sensor winding and a second sensor winding. The flux-guiding element is suitable for guiding a magnetic field during an energy transmission process taking place between another inductive charging device (1, 1b) and the energy transmission winding. The first sensor winding and the second sensor winding are arranged around at least one of the at least one flux-guiding elements. The first sensor winding has a first radial longitudinal direction and the second sensor winding has a second radial longitudinal direction. The first radial longitudinal direction is at least approximately perpendicular to the vehicle longitudinal direction or to the target vehicle longitudinal direction and the second radial longitudinal direction is at least approximately arranged in the vehicle longitudinal direction (6) or in the target vehicle longitudinal direction.

Description

Inductive charging device for a vehicle charging system

The invention relates to an inductive charging device for a vehicle charging system according to the preamble of the independent patent claim as well as a vehicle charging system and a method for positioning a vehicle.

From DE 102014 202 747 A1 a double winding system is known which serves to determine a positional deviation between a primary coil and a secondary coil of an inductive charging system. The two windings of the double winding system are offset from one another by a certain angle and wound around a common ferrite element. The magnetic field of the primary coil induces a voltage in the two windings. The two voltages are evaluated by an evaluation unit and a positional deviation between the primary coil and the secondary coil is calculated from this. Here, another component with its own ferrite element must be installed with the double winding system. Furthermore, it is not possible to position the double winding system in such a way that no or only very low voltages are induced during the charging process.

The present invention is concerned with the task of providing improved or at least alternative embodiments for an inductive charging device of the type mentioned, in particular those which reduce the complexity and increase the longevity of the components used.

Being able to charge vehicles inductively offers a variety of advantages over conventional conductive charging. Above all, the increase in comfort should be mentioned here, as it eliminates the need to handle charging cables and plugs that are sometimes very heavy. However, for the inductive charging process or energy transfer process, it is important that the inductive charging device of the vehicle is positioned as precisely as possible in relation to the stationary, for example, floor-side inductive charging device. This is done by purely manually positioning the vehicle over the stationary inductive charging device difficult and the driver needs support from an assistance system, which either provides him with information about a positional deviation between the mobile inductive charging device in the vehicle and the stationary inductive charging device, or from an automated positioning system, which automatically takes over the parking process directly. A sensor system is required that can detect a corresponding position deviation. It is advantageous here if no calibration between the stationary inductive charging device and the mobile inductive charging device in the vehicle is necessary when a vehicle approaches an unknown stationary inductive charging device.

The device according to the invention with the features of the independent patent claim has the advantage over the prior art that sensor windings are integrated into the inductive charging device, no additional magnetic core or no additional flux guide element is necessary and due to the inventive arrangement of the sensor windings, which are in place during the energy transfer process The voltages induced by the sensor windings can be reduced to a minimum. Furthermore, the proposed arrangement also makes it possible to accommodate the sensor windings in the inductive charging device in the vehicle, which is usually limited by a housing. No additional wiring is necessary, as would be the case if it were arranged outside the inductive charging device in the vehicle.

In the present case, an inductive charging device for a vehicle charging system is proposed with an energy transmission winding and at least one flux guide element and at least a first sensor winding and a second sensor winding with the following features: the flux guide element is suitable during an energy transfer process which takes place between a further inductive charging device and the energy transfer winding, to guide a magnetic field and the first sensor winding and the second sensor winding are arranged around at least one of the at least one flux guide element and the first sensor winding has a first radial longitudinal direction and the second sensor winding has a second radial Longitudinal direction and the first radial longitudinal direction is arranged at least approximately perpendicular to the vehicle longitudinal direction or to the target vehicle longitudinal direction and the second radial longitudinal direction is at least approximately arranged in the vehicle longitudinal direction or in the target vehicle longitudinal direction.

During inductive charging, energy is transferred in the form of a magnetic field between two inductive charging devices, usually between a stationary charging device and a mobile inductive charging device.

The term “inductive charging device” here refers to only one of at least two parts that are necessary for an energy transfer process. During the energy transfer process, an energy transfer winding in an inductive charging device generates an alternating magnetic field. This alternating magnetic field induces a voltage in a further energy transmission winding of a further inductive charging device. This further inductive charging device thus serves as a counterpart for this specific energy transfer process. The energy is transmitted wirelessly and absorbed by inducing a voltage.

Inductive charging devices can be used for inductively charging vehicles. In principle, an inductive charging device according to the invention can be used for any type of land, water or aircraft that has an electric or hybrid drive.

In particular, passenger cars, buses and trucks should be mentioned here.

A vehicle charging system includes at least one mobile inductive charging device and another, usually stationary, inductive charging device. A mobile inductive charging device can be mounted on and/or in a vehicle, for example. An inductive charging device on and/or in the vehicle is therefore suitable for absorbing the magnetic field and making electrical energy available from an energy storage device in the vehicle, for example a battery or accumulator in the vehicle. In principle, a vehicle charging system can also be used for bidirectional charging. The vehicle can also temporarily feed energy from the energy storage unit into the power grid via the vehicle charging system.

In general, a distinction must be made between a positioning process and an energy transfer process. The aim of the positioning process is to position the vehicle with the mobile inductive charging device as optimally as possible in relation to a specific stationary inductive charging device. An energy transfer process is only possible if the positioning is sufficiently precise, for example in a predefined target area.

During an energy transfer process, a position check process can take place at the same time. In principle, this can be done in the same way as a positioning process. The only difference is that a position check process is started at a position suitable for energy transmission and signals as soon as - for example by rolling the vehicle - a position that is no longer suitable for energy transmission is established. In principle, both the same hardware and the same algorithm can be used for a position checking process as for a positioning process. An inductive charging device has an energy transfer winding which can efficiently receive a magnetic field from a further energy transfer winding during the energy transfer process and/or can emit a magnetic field. In this case, powers of 3 kW to 500 kW can preferably be transmitted, particularly preferably 3 kW to 50 kW.

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 support. A winding is a wound arrangement of a current conductor. A winding can consist of one or more turns, with one turn being one full circuit of a conductor. In general, a winding can only consist of less than one turn, for example 0.5 turns. Of course, an incomplete number of turns, such as 2.5 turns, is also possible. An energy transmission winding can be designed in various shapes and, for example, consist of a high-frequency strand with a diameter between 0.5 mm and 10 mm, preferably made of copper.

The sensor windings are required for a positioning process and/or a position checking process. If the vehicle is still at some distance, for example between 5 and 10 m, from the stationary inductive charging device, a signal emitted by the stationary inductive charging device, preferably a magnetic field, can induce a voltage in the sensor windings. The signal emitted by the stationary inductive charging device can be emitted permanently, regardless of whether a vehicle is currently approaching or not. By comparing the voltages and a corresponding evaluation, a positional deviation between the vehicle and the stationary inductive charging device can be determined. It is also possible for the mobile inductive charging device to send out the signal and the stationary inductive charging device to receive it.

A conductor of a sensor winding can, for example, have a cross-sectional area between 0.01 and 2 mm ² . A conductor can be designed here as a strand, as a single conductor or in another form, for example in the form of a circuit board. In the case of a conductor structure realized on a circuit board, the conductor tracks can have cross sections of, for example, in the order of 0.8 mm by 35 pm.

A flux guiding element is suitable for guiding a magnetic field in a predetermined manner. It has a high magnetic permeability with p _r >1, preferably p _r >50, particularly preferably p _r >100. The flux guide element represents a magnetic core for the energy transmission winding. In particular, the magnetic field is influenced by the high permeability in such a way that the largest possible magnetic flux is transmitted to the energy transmission winding. With a flux guide element, the energy transfer winding absorbs a larger magnetic flux than without a flux guide element, with otherwise the same parameters. A flux guide element can be made of a ferromagnetic or preferably a long-range magnetic material, particularly preferably a ferrite. A flux guide element can preferably be designed like a plate - in the form of a planar core - and inductive Charging device can be arranged on the side of the energy transmission winding, which faces away from the opposite side, i.e. the further inductive charging device.

By arranging the first sensor winding and the second sensor winding around at least one of the at least one flow guide elements, the at least one of the at least one flow guide elements here assumes a dual function. It acts as a magnetic core for both the first sensor winding and/or the second sensor winding as well as a magnetic core or

Flux guiding element for the energy transmission winding. This means that no separate flux guide element is necessary for the sensor winding, which leads to simplified production.

The arrangement of a sensor winding around a flow guide element here means that at least part of the flow guide element is enclosed by a sensor winding. The first sensor winding and the second sensor winding can be arranged around the same flow guide element or around two different flow guide elements or can also be arranged around several flow guide elements.

The two sensor windings can either be arranged around only one or more flow guide elements or also around further elements, such as the energy transmission winding and/or around a cooling and/or a shielding device.

In general, a winding extends around an axis in at least two dimensions. The main direction of extension perpendicular to the winding axis is referred to here as the radial longitudinal direction. In the case of a winding with a rectangular, not square cross-section, the main direction of stretching runs along or parallel to the longer side of the rectangle. In the case of a winding with an elliptical cross section, the radial longitudinal direction runs along or parallel to the main axis of the ellipse. The radial longitudinal direction of a sensor winding according to the invention can preferably lie in a plane that extends parallel to the ground. An arrangement with the first radial longitudinal direction at least approximately perpendicular to the vehicle longitudinal direction or to the target vehicle longitudinal direction and the second radial longitudinal direction at least approximately in the vehicle longitudinal direction or in the target vehicle longitudinal direction is advantageous. On the one hand, this means that the two stand together radial longitudinal directions and thus also the two sensor windings are at least approximately perpendicular to one another, so that the components of a signal in the plane in which the vehicle moves are detected particularly well. When signal detection occurs by inducing a voltage signal through a magnetic field, the component of the magnetic field that is perpendicular to the corresponding conductor determines the strength of the induced voltage. By using two radial longitudinal directions that are at least approximately perpendicular to one another, a magnetic field can be completely detected particularly advantageously. An alignment of the radial longitudinal directions perpendicular to the vehicle longitudinal direction or to the target vehicle longitudinal direction as well as in the vehicle longitudinal direction and target vehicle longitudinal direction is advantageous because this offers manufacturing advantages. An inductive charging device and in particular flux guide elements are often designed to be rectangular and it is advantageous to design the sensor windings parallel to the edges of this rectangle. Aligning the sensor windings on the straight edges is advantageous. Sensor windings, if they are designed in the desired longitudinal direction of the vehicle or in the longitudinal direction of the vehicle, are also shorter than in an oblique or diagonal arrangement. A proportionate amount of material has to be used for the sensor windings.

The inductive charging device is preferably a mobile inductive charging device, which is arranged on and/or in a vehicle, or a stationary inductive charging device.

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. A stationary inductive charging device can preferably be located on, on or in a floor. This can be an inductive charging device applied to the subsurface or an inductive charging device sunk into a subsurface or in a floor. A floor can be a roadway, a parking lot surface, a garage floor, a floor in a parking garage or another building. Alternatively, a stationary inductive charging device can also be located on walls or the like. It is also possible that it is a stationary inductive charging device for a dynamic inductive energy transfer process. In a dynamic inductive energy transfer process, a vehicle's energy storage can be charged while it is moving. For example, in this case the stationary inductive charging device can extend along the road under, in or on the road surface.

A mobile inductive charging device can be arranged on and/or in a vehicle. In general, this refers to the part of a vehicle charging system that moves with the vehicle.

The first sensor winding and the second sensor winding are advantageously suitable for sending one or more positioning signals or receiving signals during a positioning process and/or a position checking process. The aim of a positioning process is to position the center of the energy transfer winding within a specified target area. The aim of a position check process is to detect whether the center of the energy transfer winding leaves a predetermined target area. Certain positioning signals can be used for this. These can be emitted by one or near one of the two inductive charging devices and received by the further or near the further inductive charging device. If the signals are electrical, electromagnetic or, in particular, magnetic, they can be generated and received by coils or windings.

Preferably, the first radial longitudinal direction and the second radial longitudinal direction intersect at least approximately in the center of the energy transmission winding. The center of the energy transfer winding here refers to the area a few centimeters around the geometric center of the energy transfer winding in the plane perpendicular to the winding axis of the energy transfer winding. This is advantageous because it means that the sensor windings are arranged in relation to the energy transfer winding in such a way that the lowest possible voltages are induced in the sensor windings during the energy transfer process. In one embodiment, the inductive charging device has at least four sensor windings, two of which are arranged on opposite sides of the center of the energy transmission winding and the four radial longitudinal directions of the four sensor windings run approximately through the center of the energy transmission winding.

In this embodiment, the four sensor windings are arranged like a cross around the center of the energy transfer winding, with the center of the energy transfer winding itself being free of a sensor winding.

Compared to the embodiment with two crossing sensor windings, this offers the advantage that the center of the energy transmission winding remains free of a sensor winding and thus stabilizing elements can be introduced in this area.

The four sensor windings can be connected to one another, preferably connected in series. Particularly preferably, the two opposing sensor windings are connected to one another in series.

Particularly preferred are the first radial longitudinal direction and the second radial longitudinal direction at least approximately parallel to the main direction of the magnetic field lines that form during the energy transfer process in the at least one flux guide element, in the area covered by the sensor winding.

The main direction of the magnetic field lines at the respective location means the direction in which the magnetic field lines extend mainly in the flux guide element or in the flux guide elements. The exact course of the magnetic field lines through the sensor winding should not be represented here, but the radial longitudinal directions should be based on the course of the magnetic field lines in the area of the extension of the sensor winding.

During the energy transfer process from the stationary inductive charging device to the inductive charging device in the vehicle (or vice versa), the magnetic field is guided in one or more flux guide elements. If one or more flow guide elements are plate-shaped, so During the energy transfer process, a magnetic field with magnetic field lines that run approximately radially in relation to the energy transfer winding is established in the flux guide elements. Although a voltage should be induced into the sensor windings during a positioning process and/or a position checking process in order to calculate a positional deviation between the vehicle and the stationary inductive charging device, the magnetic fields are significantly higher during the energy transfer process and it is therefore important that this is done as much as possible little voltage is induced in the sensor windings so that these or neighboring components are not destroyed. This can take advantage of the fact that the field curves of a positioning signal are significantly different from the field curves that occur during an energy transfer process. The field component perpendicular to the radial longitudinal direction of the sensor windings is relevant for the induced voltage. With an arrangement of a sensor winding that ensures that during the energy transfer process the radial longitudinal direction of the sensor winding is at least approximately parallel to the main direction of the magnetic field lines in the flux guide elements, no or only a small voltage is therefore induced in the sensor winding. In contrast, during a positioning process or a position checking process, a voltage can very well be induced in a sensor winding arranged in this way. What is important here is that an energy transfer process and a position checking process can take place at the same time. Due to the advantageous arrangement of the sensor windings, the energy transfer fields induce no or only a very low voltage in the sensor windings. This means that a position check process will not be negatively affected by the energy transfer.

The energy transmission winding is advantageously designed as a flat coil and the first sensor winding and the second sensor winding are designed as a solenoid.

A flat coil can be a spiral flat coil, in particular a circular spiral flat coil or a rectangular spiral flat coil. A spiral flat coil can be wound in the form of an Archimedean spiral. The winding shape can be similar to a circle (circular spiral flat coil), but also Other shapes, such as square-like or rectangle-like or similar to a rectangle with rounded corners, are possible (rectangular spiral flat coil). The spiral can lie in one plane. A flat coil is particularly suitable for use in a vehicle, since the installation space along the height of a vehicle is particularly limited. A flat coil is advantageous because it has the smallest possible expansion in this direction. An expansion in the two dimensions parallel to the ground and perpendicular to the height of a vehicle is advantageous because this means that the tolerance range for positioning in which the coupling between the energy transmission windings is still sufficient for energy transmission is maximally large.

A solenoid is also called a solenoid coil or solenoid coil. A solenoid can be wound in the form of a helix or a cylindrical spiral. However, the winding shape does not have to be circular, but can also have other shapes, such as square-like or rectangle-like or even similar to a rectangle with rounded corners. The important difference to the flat coil is that the turns are not in one plane, but extend along an axis. However, two or more turns can run parallel and are therefore in the same plane perpendicular to the axis.

The shape of the solenoid is well suited to detecting a signal sent by the stationary inductive charging device during a positioning process and/or a position checking process.

In an advantageous variant, the first sensor winding and/or the second sensor winding are formed by conductor tracks which are applied to at least one circuit board, preferably to at least two circuit boards.

The turns of a sensor winding are implemented in the form of conductor tracks on circuit boards.

The conductor tracks can be made of copper, for example.

The conductor tracks can be designed in multiple layers, preferably in two layers. The realization of a sensor winding using conductor tracks on circuit boards makes it possible to reduce the height of the sensor winding compared to conventional, For example, windings based on high-frequency strands can be significantly reduced.

In an alternative embodiment, the first sensor winding and the second sensor winding are designed as a stranded wire, in particular as a high-frequency stranded wire or as a wire.

A high-frequency strand consists of several wires that are insulated from each other. This offers advantages because at high frequencies the current flows mainly near the surface of a conductor and by implementing it with many individual conductors, as much conductor surface as possible is available.

The invention further relates to a vehicle charging system with a mobile inductive charging device and a stationary inductive charging device, wherein the mobile inductive charging device is designed as a positioning transmitting device and the stationary inductive charging device is designed as a positioning receiving device or the stationary inductive charging device is designed as a positioning transmitting device and the mobile inductive charging device is designed as a positioning receiving device is and the positioning receiving device is designed according to the invention.

During a positioning process, the mobile inductive charging device and the stationary inductive charging device are positioned relative to one another. One or more positioning signals can be used for this. A positioning signal can be sent out by one of the two charging devices or by a device that is assigned to one of the two charging devices. This charging device is then referred to as a positioning transmitter. A positioning signal can be received by the other charging device or by a device that is assigned to the other charging device. This loading device is then referred to as a positioning receiving device. Which charging device sends the positioning signal and which charging device receives the positioning signal is independent of which charging device sends and which receives during an energy transfer process. A positioning signal can be generated or received within the respective charging device. Alternatively, a positioning signal can be provided at the respective or generated or received at a distance from the respective charging device. A correspondingly designed vehicle charging system is advantageous because it is not only advantageously coordinated with one another during the energy transfer process, but can also work together advantageously during the positioning process through the use of sensor windings.

The inductive charging device, which does not have the sensor windings, preferably has a plurality of transmission windings, preferably four transmission windings, which are arranged at a distance from one another.

A transmitter winding is or is part of a transmitter coil that can generate a positioning signal. The positioning signal can be an alternating magnetic field and have a specific frequency or a specific frequency band. The frequencies of the positioning signals can be in the range from 5 kHz to 150 kHz, preferably in the range from 110 kHz to 148.5 kHz, particularly preferably in the range from 120 kHz to 145 kHz. A transmitter coil can be designed to be significantly smaller than an energy transmission winding and can also be designed to be smaller than a sensor winding. A transmission winding can be designed, for example, in the form of a flat coil. The transmission windings can be arranged at a distance from the energy transmission winding and at a distance from the flow guide element(s). Alternatively, a transmission winding can also be arranged in the area of the energy transmission winding and/or in the area of the flow guide elements. In principle, a transmitter winding can be arranged in every level of an inductive charging device. For inductive charging devices arranged horizontally (i.e. parallel to the travel plane), this corresponds to an arrangement at different heights. A transmission winding can be arranged between the at least one flux guide element and the energy transmission winding. Alternatively, a transmission winding can lie in a plane with the energy transmission winding. In a further alternative embodiment, a transmission winding can be closer to the further inductive charging device, which forms the counterpart during an inductive charging process, than the energy transmission winding and than the flux guide elements. In other words, a transmission winding can be on the side of the energy transmission winding facing away from the flux guide elements be arranged. It is also possible for the transmitter windings to be arranged at a spatial distance from the inductive charging device and to be assigned to it only functionally. By using multiple transmitter windings, a simpler positioning procedure is possible.

If the received signals can be assigned to the individual positioning signals of the transmission windings, the relative or absolute distance to the respective transmission windings can be determined from this and positioning can thus take place. For example, the relative distances to two adjacent transmission windings can be compared.

The use of four transmitter windings is advantageous. For example, they can be arranged in the form of a rectangle around a target area. By simply comparing the intensities of the respective different positioning signals, positioning can be carried out both in the longitudinal direction of the vehicle and perpendicular to the longitudinal direction of the vehicle. Another advantage is that there is redundancy, since two ratios are formed in each spatial direction. This is particularly relevant for the proposed system, since parasitic effects can occur at very short distances between the transmitter winding and the sensor winding, so that the spatially distributed signals no longer have their maximum directly at the position of the transmitter winding, but there is a pronounced "dip" there. is available. A “dip” here is a local minimum between two local maxima. The position-dependent signal therefore has a characteristic curve with a “double hump”. Such a course leads to a falsification of the recognized position. Since the effect of the pronounced “dips” in the spatial distribution only occurs at very short distances, the redundancy proposed here is advantageous because the signals from the transmitter windings can always be evaluated at greater distances.

Particularly preferably, during a positioning process and/or a position checking process, the transmitter windings send out positioning signals which differ in at least one distinguishing criterion and the sensor windings are suitable for receiving the positioning signals. The differentiation criterion must be chosen so that the signals can be clearly separated from each other after reception and can be assigned to the individual transmission windings. An advantageous simple evaluation is then possible, in which a relative or absolute distance to the transmitter windings can be deduced from the intensity of the individual signals.

The distinguishing criterion is advantageously one or more frequencies or one or more pulse widths.

If an alternating field, in particular an alternating magnetic field, is used as a signal, the frequency and the pulse width are the two simplest and most advantageous options for implementing a differentiation criterion. Both criteria are also suitable for easily separating the signals when superimposed. When using different frequencies, a transformation occurs in the frequency range and different frequency ranges can then be assigned to the respective signals.

The frequencies associated with the transmission windings are preferably as close to one another as possible. The frequencies are, for example, between 5 kHz and 100 Hz. The frequencies are particularly preferably 200 Hz apart. Alternatively, it is also possible for the frequencies to be 500 Hz apart. Since the use of frequencies is subject to legal regulations and the frequency spectrum is divided into certain frequency bands, it can be advantageous to choose the frequencies so close to each other that all frequencies used are in the same frequency band. At the same time, a minimum distance between frequencies is necessary in order to be able to distinguish between them. For example, the frequencies 130 kHz, 130.5 kHz, 131 kHz and 131.5 kHz can be used for the positioning signals. Alternatively, for example, the frequencies 125 kHz, 130 kHz, 135 kHz and 140 kHz can be used for the positioning signals.

Alternatively or additionally, it is conceivable to generate the positioning signals with associated pulse widths so that the positioning signals can be distinguished. The use of pulse widths means that the positioning signals can preferably be generated within the same frequency band. This also leads in particular to a reduced influence of the positioning device on nearby components.

The four transmission windings are preferably arranged at least approximately symmetrically around the center of the energy transmission winding of the inductive charging device, which does not have the sensor windings.

In particular, if the positioning signals emitted by the transmission windings can be distinguished from one another, a positioning process or a position checking process is possible simply by comparing the intensities of the positioning signals.

Alternatively, it is possible to choose the distance between the transmitter windings perpendicular to the vehicle's longitudinal direction or desired vehicle's longitudinal direction to be smaller - in particular at least 10% smaller - than the distance between the transmitter windings in the vehicle's longitudinal direction or desired vehicle's longitudinal direction. In such an embodiment, a higher accuracy can be achieved in the longitudinal direction of the vehicle or the desired longitudinal direction of the vehicle than in the direction perpendicular thereto. This has the advantage that if there is an offset in the longitudinal direction of the vehicle or the desired longitudinal direction of the vehicle, it can be responded to by simply driving forwards or backwards. If there is an offset in the direction perpendicular to this, re-shunting is necessary. In this case, the priority must therefore be to determine that there is an offset. How large this offset is is of secondary importance.

The invention further relates to a method for positioning a vehicle with a mobile inductive charging device in a defined position relative to a stationary inductive charging device, the mobile inductive charging device and the stationary inductive charging device being part of a vehicle charging system according to the invention.

An energy transfer process is only possible if the positioning is sufficiently precise. A defined position is therefore preferred chosen that the two energy transmission coils of the mobile inductive charging device and the stationary inductive charging device are arranged relative to one another in such a way that energy transmission with a sufficiently high level of efficiency is possible.

Particularly preferably, the defined position is defined in that, in a top view of the mobile inductive charging device and the stationary inductive charging device, a reference point on the mobile inductive charging device is positioned in a target area on the stationary inductive charging device. In the case of a mobile inductive charging device, which is arranged, for example, below a vehicle, and a stationary inductive charging device, which is arranged on a surface, the height distance between the mobile and the stationary inductive charging device is fixed. A method for positioning a vehicle is thus reduced to a two-dimensional positioning process in which the vehicle is positioned in a plane parallel to the ground. For this purpose, a top view of the mobile and stationary inductive charging device can be used. A top view is a top view of the areas in which the stationary and mobile inductive charging devices mainly extend.

A sufficiently precise position can be specified with respect to a reference point on the mobile inductive charging device. A reference point can be the center of an energy transmission winding of a mobile inductive charging device. If the reference point is positioned with sufficient precision, the mobile inductive charging device and therefore also the vehicle are positioned with sufficient precision. A sufficiently precise positioning can be determined by a predefined target area on the stationary inductive charging device. The target area can be an imaginary area. A target area can be within 100 mm of an optimal position. For example, an optimal position can be a position in which the two centers of the two energy transfer windings lie one above the other. A target area can be a 200 mm by 150 mm rectangle, with the optimal position being at the center of this target area. Using transmitted and received positioning signals, the vehicle can advantageously be positioned during a positioning process so that the center of the energy transmission winding is within a predetermined target area.

Using transmitted and received positioning signals, it can be checked during a position check process whether the vehicle is positioned such that the center of the energy transfer winding is within a predetermined target area.

The proposed method for positioning a vehicle is advantageous because very precise positioning in a predefined target area is possible. The positioning method presented here can be used as soon as a vehicle has fallen below a minimum distance from a target position. Such a minimum distance can be between 20 and 60 cm, for example. Such a minimum distance can be met as soon as the inductive charging device is at least partially in the area spanned by the transmitter coils.

The method according to the invention preferably includes that signals received in the two sensor windings are detected and processed and a total signal is determined from the received signals and the total signal is divided into several partial signals depending on the differentiation criterion and a position deviation value is determined depending on the partial signals. The use of at least two sensor windings is advantageous because it eliminates the dependence of the received signals on the angle.

In both sensor windings, a superimposition of the signals from the different transmission coils, which differ in the differentiation criterion, is initially received. An overall signal is then determined from the signals received from the two sensor windings. In the simplest case, this can be done by adding the two received signals. The resulting overall signal is now independent of the respective angles between the positioning signal and the sensor windings. The overall signal is then divided into several partial signals. The decisive factor here is the differentiation criterion used. When using the frequency as Differentiation criterion, the signal can be transformed into the frequency range. The signal can then be divided into several sub-signals by assigning a specific frequency range to each sub-signal.

The acquisition and processing of the received signals particularly preferably includes: the received signals are sampled in an analog-to-digital conversion unit and converted into digital signals and the digital signals are transformed into the frequency range in an evaluation unit.

An evaluation unit can be implemented on a chip, on a control unit, a local processor or another local computing unit. Alternatively, an evaluation unit can be implemented on a central computing unit.

During a frequency transformation, a signal from the time domain is mathematically transformed into the frequency domain. For a time-dependent signal, an evaluation in the frequency domain provides information about how strong a specific frequency or frequency range is present in this signal.

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

The transformation into the frequency range is advantageously implemented by a discrete Fourier transformation, in particular by a fast Fourier transformation (FFT).

A discrete Fourier transformation (DFT for short) transforms a signal sampled in the time domain into a discrete frequency signal using a Fourier transformation. Here the voltage signal induced in the sensor windings is sampled discretely. What is relevant here is the sampling frequency, which determines which frequencies can be resolved. The sampling frequency must be chosen so that the relevant frequencies, in particular the excitation frequency, can be resolved. A special, optimized form of discrete Fourier transformation is the fast Fourier transformation (FFT for short). Since the optimized algorithm minimizes the complexity and thus the computational effort, the FFT is the most commonly implemented form of discrete Fourier transformations. Advantageously, a partial signal value is determined from each partial signal and a ratio is calculated by division from two partial signal values and, depending on the ratios, a position deviation value is determined until all ratios are within a predetermined tolerance range. The partial signals can be used to determine and correct the position deviation. For this purpose, a partial signal value can first be determined from a partial signal, for example by determining the maximum of the partial signal or by adding up the frequency- or time-dependent components of the partial signal. Two partial signal values can now be related to each other. The aim of the positioning process is to ensure that the conditions are within a certain tolerance range around a target value. The aim of a position check process is to check whether the conditions are within a certain tolerance range around a target value. With a symmetrical arrangement of the transmitter windings around the inductive charging device, the setpoint for the ratio can preferably be 1. A tolerance range for the conditions can be selected in such a way that it is ensured that the center of the energy transmission winding is located in a predefined spatial target area around a position that is optimal for energy transmission. As long as one or more ratios are outside the tolerance range, a position deviation value is calculated from the ratios. This can then be transferred to another computing unit or to a display element.

Using the conditions to detect the relative position of the inductive charging devices or the energy transmission windings to one another has the particular advantage that repeated calibration of the inductive charging devices to one another can be dispensed with.

In a preferred embodiment, the position deviation value or a value derived from the position deviation value is transferred via a data interface to a bus system, preferably to a CAN bus or to another computing unit.

A corresponding value is passed on via a data interface. A corresponding value generally has a time-dependent course. It can be passed on to a bus system. A bus system is a system that is used to enable the transmission of data between individual participants within a network. The transmission of data is based on special protocols. A protocol commonly found in vehicles is the CAN protocol. “CAN” stands for “Controller Area Network” and a CAN bus is a field bus.

As an alternative to passing it on to a bus system, a corresponding value can also be passed on to another computing unit. The further computing unit can be physically connected to the evaluation unit or not.

Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or alone, without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, with the same reference numbers referring to the same or similar or functionally the same components.

It shows each schematically

1 shows a simplified representation of a vehicle with a mobile inductive charging device positioned above a stationary inductive charging device,

2 shows an inductive charging device according to the invention with sensor windings, 3 shows a simplified top view of a mobile inductive charging device according to the invention above a stationary inductive charging device according to the invention,

4 shows a schematic representation of the signal processing of two positioning signals with different frequencies,

5 shows a simplified representation of the positioning signals emitted by transmitter windings, which are detected in sensor windings,

6 is a top view of an inductive charging device with four sensor windings,

7 is a top view of a sensor winding,

Fig. 8 shows a representation of the spatial course of two partial signal values.

1 shows a mobile inductive charging device 1a, which is arranged on a vehicle 2 with an energy storage device 3 and is positioned above a stationary inductive charging device 1b. During operation, energy can be transferred from the stationary inductive charging device 1b to the mobile inductive charging device 1a and the energy storage of the vehicle 3 can thereby be charged.

The mobile inductive charging device 1a and the stationary inductive charging device 1b form together or are part of a vehicle charging system 8. In principle, it is also possible to operate the vehicle charging system 8 bidirectionally. Energy can temporarily be transferred from the mobile inductive charging device 1a to the stationary inductive charging device 1b. The stationary inductive charging device 1 b arranged on the ground in FIG. 1 can alternatively also be arranged recessed in the road (not shown here). In the case of a recessed arrangement, the inductive charging device 1b can be covered by certain layers of the road or flush with the road surface complete. The stationary inductive charging device here has several transmitter windings 13, with two transmitter windings 13 being visible in the side view.

2 shows a top 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. The inductive charging device 1 has a plurality of flow guide elements 5. There are narrow gaps 32 between the flow guide elements 5. The energy transmission winding 4 here is a flat coil 10. 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 first radial longitudinal direction 11a is perpendicular to the vehicle longitudinal direction 6 and the first sensor winding 9a is arranged around a plurality of flow guide elements 5. The second radial longitudinal direction 11b is aligned in the vehicle longitudinal direction 6 and the second sensor winding 9b is arranged around a plurality of flow guide elements 5. The sensor windings are designed here as a solenoid, also known as a solenoid coil. The first radial longitudinal direction 11a and the second radial longitudinal direction 11b intersect or intersect at least approximately in the center 7 of the energy transmission winding 4.

During the energy transfer process, the vehicle 2 is positioned above the stationary inductive charging device 1b and energy is transferred to the mobile inductive charging device 1a. The flow guidance elements 5 take on the function of flow guidance. When charged, the field lines of the magnetic field run approximately in a radial direction. 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 14, only relatively little to no voltage is induced in the first sensor winding 9a and in the second sensor winding 9b. This is important because, given the high performance of the energy transfer process and thus high flux densities, the sensor windings could easily be destroyed. Additional effort to prevent the arrangement from being destroyed is therefore not necessary. Fig. 3 shows a schematic top view of a mobile inductive charging device 1a, which is positioned above a stationary inductive charging device 1b. Here the mobile inductive charging device is designed as a positioning receiving device 24a and the stationary inductive charging device 1b is designed as a positioning transmitting device 24b. The mobile inductive charging device 1a is shown without the vehicle 2 on which it is mounted. The mobile inductive charging device 1a has an energy transmission winding 4 in the form of a flat coil 10 and several flux guide elements 5. A first sensor winding 9a and a second sensor winding 9b are located around several of the flow guide elements 5 and around the energy transmission winding 4. The two sensor windings are arranged as described in FIG. 2. The magnetic field lines during an energy transfer process (not shown) run approximately radially outwards from the center 7 of the energy transfer winding 4 in the mobile inductive charging device 1a. Thus, the radial longitudinal directions 11 of the sensor windings 9 run parallel to the main direction of the magnetic field lines at this specific location during an energy transfer process. Therefore, no or only a very small voltage is induced in the sensor windings by an energy transfer process. The mobile inductive charging device 1a is positioned centrally above the stationary inductive charging device 1b. The stationary inductive charging device 1b has four transmitter windings 13a, 13b, 13c, 13d. The transmitter windings 13a, 13b, 13c, 13d can emit positioning signals during a positioning process or a position checking process, which can be detected in the sensor windings 9a, 9b.

The schematic representation in FIG. 4 demonstrates how positioning is possible using a differentiation criterion. The frequency is used as the distinguishing criterion here. In the present example, the positioning signals 12a, 12b, which are generated by the two transmission windings 13a, 13b, differ in frequency. The two sensor windings 9a, 9b now receive both positioning signals 12a, 12b. The intensity of a specific positioning signal 12a or 12b detected in the respective sensor winding 9a or 9b is dependent on both the angular orientation of the corresponding transmitter winding 13a or 13b respective sensor winding 9a or 9b as well as the respective distance between transmitter winding 13a or 13b and sensor winding 9a or 9b. The received signals 15 of the two sensor windings 9a or 9b are now mathematically combined, in the simplest case added.

An overall signal 16 is now obtained, which is independent of the angular orientation between the transmitter windings 13a, 13b and the sensor windings 9a, 9b. This overall signal 16 can now be divided again into the different frequency components. In the simplified representation, all signals are shown in the frequency range. However, time-dependent signals are actually received in the sensor windings 9a, 9b. As part of signal processing, these are then transformed into the frequency range. This is preferably done after the received signals 15 have been combined into an overall signal 16. In the frequency range, the overall signal 16 can now be divided into different partial signals 17. Each partial signal contains a certain bandwidth around the frequency of the corresponding positioning signal 12a, 12b.

In Fig. 5, the mobile inductive charging device is designed as a positioning receiving device 24a and the stationary inductive charging device 1b is designed as a positioning transmitting device 24b. The stationary inductive charging device 1 b has four transmitter windings 13a, 13b, 13c, 13d, which emit four positioning signals 12a, 12b, 12c, 12d that differ in a distinguishing criterion. The positioning signals 12a, 12b, 12c, 12d are, for example, magnetic fields and are indicated as circles in FIG. 5, since they expand radially around the respective transmitter winding 13a, 13b, 13c, 13d. The positioning signals 12a, 12b, 12c, 12d can be magnetic near fields, for example. The circles therefore only indicate a possible spatial distribution of a signal and are not intended to symbolize any wave properties of the positioning signals 12a, 12b, 12c, 12d. All four positioning signals 12a, 12b, 12c, 12d are detected by both sensor windings 9a, 9b. Since the two sensor windings 9a, 9b are perpendicular to one another, the angular dependence of the signals can be calculated out by appropriate mathematical processing of the signals in the two sensor windings. There is then only one difference in the intensities of the signals Difference in the distance between transmitter winding 13a, 13b, 13c, 13d and mobile inductive charging device 1a. A partial signal value is now determined for each partial signal and a ratio is calculated from the partial signal values with the partial signal value of the directly adjacent transmitter winding 13a, 13b, 13c, 13d. If these conditions are within a certain tolerance range, the reference point 33 of the mobile inductive charging device 1a, which here is the center 7 of the mobile inductive charging device 1a, is located in a predefined target area 22.

Fig. 6 shows a top view of an inductive charging device 1 with an energy transmission winding 4, which is designed as a flat coil 10 and a plurality of flux guide elements 5. The inductive charging device 1 also has four transmission windings 13a, 13b, 13c, 13d, which are symmetrical about the center 7 the energy transmission winding 4 are arranged.

Fig. 7 shows a transmission winding 13, which is designed as a flat coil 10.

In Fig. 8 two transmission windings 13 are shown, which emit two positioning signals 12 with two different frequencies f1 and f2. From the two positioning signals 12, the maximum values at the two frequencies f1 and f2 were evaluated as partial signal values 23. The spatial course of the maximum values is shown schematically here. The spatial course shown here represents the spatial course at a sufficient distance between transmitter windings 13 and sensor windings 9. The intensity of the maximum values decreases with the distance to the respective transmitter winding 13, similar to a Gaussian distribution. For smaller distances between transmitter windings 13 and sensor windings 9, a corresponding spatial distribution has a pronounced “dip”, i.e. a local minimum between two local maxima, in the area of the maximum shown here. Such a “dip” therefore distorts the precise determination of a position. It is therefore advantageous that the system presented here is designed to be redundant and signals from several transmission windings 13 can be used for the evaluation. Reference list

1 inductive charging device

1a mobile inductive charging device

1 b stationary inductive charging device

2 vehicle

3 vehicle energy storage

4 energy transfer winding

5 flow guide element

6 vehicle longitudinal direction

6a Target vehicle longitudinal direction

7 center of energy transmission winding

8 vehicle charging system

9 sensor winding

9a first sensor winding

9b second sensor winding

10 flat spools

11 radial longitudinal direction

11a first radial longitudinal direction

11b second radial longitudinal direction

12 positioning signal

12a first positioning signal

12b second positioning signal

12c third positioning signal

12d fourth positioning signal

13 transmission winding

13a first transmission winding

13b second transmission winding

13c third transmission winding

13d fourth transmission winding

14 Main direction of the magnetic field lines

15 received signal

16 total signal

17 partial signal

18 analog-digital conversion unit Evaluation unit Electronic device metallic shielding optionally with cooling function Target area Partial signal value a Positioning receiving device b Positioning transmitting device Gap between flow guide elements Reference point

Claims

Claims Inductive charging device (1) for a vehicle charging system (8) with an energy transmission winding (4) and at least one flow guide element (5) and at least a first sensor winding (9a) and a second sensor winding (9b), with the following features: - the flux guide element (5) is suitable for guiding a magnetic field during an energy transfer process which takes place between a further inductive charging device (1) and the energy transfer winding (4) and - the first sensor winding (9a) and the second sensor winding (9b) are arranged around at least one of the at least one flow guide element (5) and - 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) and - the first radial longitudinal direction (11a) is arranged at least approximately perpendicular to the vehicle longitudinal direction (6) or to the target vehicle longitudinal direction (6a) and the second radial longitudinal direction is at least approximately arranged in the vehicle longitudinal direction (6) or in the target vehicle longitudinal direction (6a). Inductive charging device (1) according to claim 1, characterized in that - the inductive charging device (1) is a mobile inductive charging device (1a), which is arranged on and/or in a vehicle (2), or that - The inductive charging device (1) is a stationary inductive charging device (1b). Inductive charging device (1) according to one of the preceding claims, characterized in that the first sensor winding (9a) and the second sensor winding (9b) are suitable for sending one or more positioning signals (12) or signals ( 15) to receive. Inductive charging device (1) according to one of the preceding claims, characterized in that the first radial longitudinal direction (11a) and the second radial longitudinal direction (11 b) intersect at least approximately in the center (7) of the energy transmission winding (4). Inductive charging device (1) according to one of the preceding claims, characterized in that the first radial longitudinal direction (11a) and the second radial longitudinal direction (11 b) are at least approximately parallel to the main direction of the magnetic field lines (14), which are in the at least one during the energy transfer process Flow guide element (5) forms in the area covered by the sensor winding. Inductive charging device (1) according to one of the preceding claims, characterized in that the energy transmission winding (4) is designed as a flat coil (10) and the first sensor winding (9a) and the second sensor winding (9b) are designed as a solenoid. Vehicle charging system (8) with a mobile inductive charging device (1a) and a stationary inductive charging device (1b), wherein - the mobile inductive charging device (1a) is designed as a positioning transmitting device (24b) and the stationary inductive charging device (1b) is designed as a positioning receiving device (24a) or - the stationary inductive charging device (1b) as a positioning transmitter device (24b) and the mobile inductive Charging device (1a) is designed as a positioning receiving device (24a) and - The positioning receiving device (24a) is an inductive charging device according to one of the preceding claims. Vehicle charging system (8) according to claim 7, wherein the positioning transmitter (24b) has a plurality of transmitter windings (13a, 13b, 13c, 13d), preferably four transmitter windings (13a, 13b, 13c, 13d), which are arranged spaced apart from one another. Vehicle charging system (8) according to claim 8, characterized in that - the transmitter windings (13a, 13b, 13c, 13d), during a positioning process, emit positioning signals (12a, 12b, 12c, 12d), which differ in at least one distinguishing criterion, and - The sensor windings (9a, 9b) are suitable for receiving the positioning signals (12a, 12b, 12c, 12d). Vehicle charging system (8) according to claim 9, wherein the distinguishing criterion is one or more frequencies or one or more pulse widths. Vehicle charging system (8) according to one of claims 8-10, characterized in that the four transmitter windings (13a, 13b, 13c, 13d) are arranged at least approximately symmetrically around the center (7) of the energy transmission winding (4) of the positioning transmitter device (24b). . Method for positioning a vehicle (2) with a mobile inductive charging device (1a) in a defined position relative to a stationary inductive charging device (1 b), wherein the mobile inductive charging device (la) and the stationary inductive charging device (1b) are part of a vehicle charging system (8) according to one of claims 7-11. Method according to claim 12, characterized in that the defined position is defined in that, in a top view, of the mobile inductive charging device (1a) and the stationary inductive charging device (l b), a reference point (33) on the mobile inductive charging device (1a) is positioned in a target area (22) on the stationary inductive charging device (1 b). Method according to claim 12 or claim 13, characterized in that - Signals (15) received in the two sensor windings (9a, 9b) are detected and processed and - an overall signal (16) is determined from the received signals (15) and - the overall signal (16) is divided into several partial signals (17) depending on the differentiation criterion and - A position deviation value is determined depending on the partial signals (17). Method according to claim 14, characterized in that detecting and processing the received signals (15) includes: - The received signals (15) are sampled in an analog-digital conversion unit (18) and converted into digital signals and - The digital signals are transformed into the frequency range in an evaluation unit (19). Method according to claim 14 or claim 15, characterized in that - A partial signal value (23) is determined from each partial signal (17) and - A ratio is calculated from two partial signal values (23) by division and - Depending on the conditions, a position deviation value is determined until all conditions are within a predetermined tolerance range.