Inductive charging system and methods for improving the coupling factor

Abstract

Inductive charging system (300) for charging an energy storage device (103); wherein the charging system (300) comprises, - a primary coil (111) configured to generate a magnetic field (250) for the transmission of energy; - a secondary coil (121) which is configured to generate a current for charging the energy storage device (103) depending on the magnetic field (250); - a rotary actuator (311) configured to rotate the primary coil (111) and / or the secondary coil (121); and - a control unit (312) that is set up, - to determine rotation information indicating how to rotate the primary coil (111) and / or the secondary coil (121) in order to improve a transmission property (231) of the inductive charging system (300); and - to control the rotary actuator (311) depending on the rotation information.

Description

[0001] The invention relates to an inductive charging system comprising means for improving a transmission characteristic, in particular a coupling factor, of the charging system. Furthermore, the invention relates to a method for improving the transmission characteristic of an inductive charging system.

[0002] Electric vehicles typically have a battery (i.e., an electrical energy storage device) that stores electrical energy to power the vehicle's electric drive motor. The vehicle's battery can be recharged using electrical energy from a power grid. For this purpose, the battery is connected to the power grid to transfer electrical energy from the grid to the vehicle's battery. This connection can be wired (via a charging cable) and / or wireless (using inductive coupling between a charging station and the vehicle).

[0003] One approach to automatic, wireless, inductive charging of the vehicle's battery involves transferring electrical energy from the ground to the vehicle's underbody via magnetic induction across the underbody clearance. This is exemplified in Fig. 1 shown. In particular, it shows Fig. 1. A vehicle 100 with an energy storage device 103 for electrical energy (e.g., with a rechargeable battery 103). The vehicle 100 includes a secondary coil 121 in the vehicle underbody, the secondary coil 121 being connected to the electrical energy storage device 103 via a rectifier. The rectifier is part of secondary electronics 123. The secondary coil 121 and the secondary electronics 123 are typically electrically connected to each other via at least one (AC) line 122 and together form a so-called “Wireless Power Transfer” (WPT) vehicle unit 120 or secondary unit 120.

[0004] The secondary coil 121 of the secondary unit 120 can be positioned above a primary coil 111, the primary coil 111 being, for example, mounted on the floor of a garage. The primary coil 111 is typically part of a so-called WPT ground unit 110 or primary unit 110. The primary coil 111 is connected via an (AC) line 112 to primary electronics 113 and further to a power supply. The primary electronics 113 can include a radio frequency generator or inverter that generates an AC (alternating current) current in the primary coil 111 of the WPT ground unit 110, thereby inducing a magnetic field (in particular, a magnetic charging field). The magnetic charging field can have a frequency from a predefined charging field frequency range. The charging field frequency of the electromagnetic charging field can be in the range of 80–90 kHz (in particular, 85 kHz).

[0005] With sufficient magnetic coupling between the primary coil 111 of the primary unit 110 and the secondary coil 121 of the secondary unit 120 (i.e., with a sufficiently high coupling factor or degree of coupling) across the underbody clearance 130, a corresponding voltage and thus also a current is induced in the secondary coil 121 by the magnetic field. The induced current in the secondary coil 121 of the secondary unit 120 is rectified by the rectifier of the secondary electronics 123 and stored in the energy storage device 103. In this way, electrical energy can be wirelessly transferred from a power supply to the energy storage device 103 of the vehicle 100. The charging process in the vehicle 100 can be controlled by a charging control unit of the secondary electronics 123. For this purpose, the charging control unit can be configured to communicate with the primary unit 110, for example, wirelessly (e.g., via WLAN).

[0006] Vehicles 100 can be parked offset above a ground unit 110, resulting in a translational offset between the primary coil 111 and the secondary coil 121. Consequently, the coupling factor and thus the efficiency of the charging process can be reduced.

[0007] This document addresses the technical challenge of providing an inductive charging system that enables efficient charging even in situations where the primary coil and the secondary coil are misaligned.

[0008] The problem is solved by the independent claims. Advantageous embodiments are described, inter alia, in the dependent claims. It should be noted that additional features of a claim dependent on an independent claim, without the features of the independent claim itself or only in combination with a subset of the features of the independent claim, can constitute a separate invention independent of the combination of all features of the independent claim, which can be made the subject of an independent claim, a divisional application, or a subsequent application. This applies equally to technical teachings described in the description, which can constitute an invention independent of the features of the independent claims.

[0009] According to one aspect, an inductive charging system for charging an energy storage device is described. The energy storage device can be located in a vehicle, particularly a road vehicle such as a passenger car, bus, motorcycle, truck, etc. The charging system comprises a primary coil (particularly as part of a primary unit) configured to generate a magnetic field (particularly a charging field with a charging field frequency, e.g., in the range between 80 kHz and 90 kHz) for energy transfer. The charging system also comprises a secondary coil (e.g., as part of a secondary unit) configured to generate a current for charging the energy storage device, depending on the magnetic field. In particular, an alternating current can be induced in the secondary coil by the (alternating current) magnetic field. This current can then be rectified and directed to the energy storage device.The primary coil and / or the secondary coil can each comprise a circular coil and / or a double D coil.

[0010] The charging system further comprises at least one (controllable and / or electrically driven) rotary actuator configured to rotate the primary coil and / or the secondary coil (in particular, relative to each other). It is possible to rotate either the primary coil but not the secondary coil, or the secondary coil but not the primary coil. In other words, one of the two coils can be stationary while the other is rotated. This allows for efficient relative rotation between the primary and secondary coils. Specifically, the provision of a rotary actuator can thus be limited to either the primary unit or the secondary unit.

[0011] Furthermore, the charging system includes a control unit (e.g., as part of the primary unit and / or the secondary unit). The control unit is configured to determine rotation information indicating how the primary coil and / or the secondary coil should be rotated, particularly relative to each other, to improve (especially optimize) a transmission characteristic of the inductive charging system. This transmission characteristic may include a coupling factor between the primary and secondary coils and / or a maximum transmissible electrical power between the primary and secondary coils. The rotation information may also indicate a rotation angle at which the primary and / or secondary coils should be rotated to improve (especially optimize) the transmission characteristic of the inductive charging system.

[0012] The control unit is further configured to control the rotary actuator based on the rotation information. The inductive charging system is thus designed to efficiently improve a transmission characteristic by rotating the primary coil and / or the secondary coil. In particular, the charging system can efficiently compensate, at least partially, for translational misalignment between the primary and secondary coils. Alternatively or additionally, rotating the primary and / or secondary coil can provide a charging system with increased misalignment tolerance.

[0013] A primary axis of the primary coil can run perpendicular to a winding of the primary coil. In particular, the winding can be wound around the primary axis of the primary coil. The winding can run within a primary area. The primary axis can optionally pass centrally through the winding. Similarly, a secondary axis of the secondary coil can run perpendicular to a winding of the secondary coil. In particular, the winding can be wound around the secondary axis of the secondary coil. The winding can run within a secondary area. The secondary axis can optionally pass centrally through the winding.

[0014] The winding of the primary coil can thus be arranged within a surface that can be referred to as the primary surface. The primary axis can then be perpendicular to the primary surface. The rotary actuator can be configured to cause a rotation of the primary coil around the primary axis and / or a change in the orientation of the primary axis or the primary surface. A change in the orientation of the primary axis or the primary surface can be achieved by a rotation around a first axis (e.g., an x-axis or an axis parallel to the x-axis) of the primary surface and / or by a rotation around a second axis (e.g., a y-axis or an axis parallel to the x-axis) of the primary surface.

[0015] Similarly, the winding of the secondary coil can be arranged within a surface that can be referred to as the secondary surface. The secondary axis can then be perpendicular to the secondary surface. The rotary actuator can be configured to cause a rotation of the secondary coil about the secondary axis and / or a change in the orientation of the secondary axis or the secondary surface. A change in the orientation of the secondary axis or the secondary surface can be achieved by a rotation about the first axis (e.g., the x-axis or an axis parallel to the x-axis) of the secondary surface and / or by a rotation about the second axis (e.g., the y-axis or an axis parallel to the x-axis) of the secondary surface.

[0016] In a home position of the primary and secondary coils, the primary and secondary axes can be parallel to each other. Alternatively or additionally, the primary surface of the primary coil and the secondary surface of the secondary coil can be parallel to each other in the home position. The primary and secondary surfaces can be spaced apart along the z-axis of a Cartesian coordinate system. This distance along the z-axis corresponds to the coil spacing between the primary and secondary coils in the home position. Furthermore, the primary and secondary surfaces can be parallel to the plane defined by the x- and y-axes of the Cartesian coordinate system in the home position.

[0017] The one or more rotary actuators can be configured to rotate the primary coil and / or the secondary coil such that the primary and secondary axes are no longer parallel to each other and / or that the primary and secondary surfaces are no longer parallel to each other. For this purpose, the primary surface can be rotated about the first and / or second axis while the secondary surface remains stationary. Alternatively, the secondary surface can be rotated about the first and / or second axis while the primary surface remains stationary. In this way, rotating one of the two coils efficiently improves the transfer characteristics of the inductive charging system. In particular, this increases the coupling factor of the charging system.

[0018] As explained above, the primary and secondary coils can have a translational offset relative to each other. In particular, a primary axis running centrally through the primary coil can have a lateral offset (perpendicular to the z-axis) relative to a secondary coil running centrally through the secondary coil. This offset can then be determined as the lateral distance between the centrally running primary axis and the centrally running secondary axis (assuming the primary and secondary axes are parallel, i.e., in their home position). By rotating the primary and / or secondary coils, the negative effects of this lateral offset on a transmission characteristic of the inductive charging system, especially on the coupling factor, can be at least partially compensated.

[0019] The secondary coil can be located in a vehicle (especially a road vehicle). The vehicle can include one or more vehicle actuators, in particular a (possibly air-sprung) shock absorber, with which the vehicle's tilt can be changed. The rotary actuator can then comprise one or more of these vehicle actuators. Thus, the rotation of the secondary coil can be achieved, at least partially, by tilting the entire vehicle. One or more vehicle actuators already installed in the vehicle for its operation can be used. This allows for a particularly efficient rotation of the secondary coil.

[0020] The rotary actuator can, for example, comprise an electrically driven actuator (such as an electric motor). The rotary actuator can be configured to move the primary coil relative to a charging station in which the primary coil is located. Alternatively or additionally, the rotary actuator can be configured to move the secondary coil relative to a device, particularly a vehicle, in which the secondary coil and, if applicable, the energy storage device are located. Thus, the rotary actuator can effect relative movement between the primary coil and the charging station and / or between the secondary coil and the vehicle. This allows for precise rotation of the primary coil and / or the secondary coil. In particular, a specific angle of rotation of the primary coil and / or the secondary coil can be precisely controlled.

[0021] The control unit can be configured to determine offset information regarding a translational or lateral offset distance between the primary coil and the secondary coil. This offset distance can depend on or correspond to the distance between the centrally located primary axis and the centrally located secondary axis (assuming that the primary coil and the secondary coil are in their home position).

[0022] The rotation information can then be determined based on the offset information. In particular, the rotation angle to be set for the primary coil and / or the secondary coil (to improve the transmission characteristics) can be determined based on the translational offset distance. The rotation angle can indicate the target angle of the primary or secondary axis after rotation relative to the primary or secondary axis in the initial position of the primary or secondary coil. In a vehicle charging system, the primary or secondary axis can be perpendicular to the road surface traveled by the vehicle in its initial position. The rotation angle can consist of a first angle for rotation about the first axis (e.g., the x-axis or an axis parallel to the x-axis) and a second angle for rotation about the second axis (e.g., the y-axis or an axis parallel to the x-axis).

[0023] In particular, key parameters for a specific charging system can be determined in advance. These parameters provide corresponding rotational information for different offset distances between the primary and secondary coils, enabling improvements, especially optimization, of the charging system's transmission characteristics. For example, the rotational angle for the primary and / or secondary coil that should be set for a specific offset distance can be determined in advance. This offset distance can comprise a first distance along the first axis (e.g., the x-axis) and a second distance along the second axis (e.g., the y-axis). Thus, different rotational angles can be determined for different offset distances, which can improve, and in particular optimize, the transmission characteristics. In this way, key parameters for the rotation of the primary and / or secondary coil can be determined.Furthermore, the control unit can thus determine the rotation information for controlling the rotary actuator based on the characteristic data. By taking offset information and, if applicable, characteristic data into account, an optimal setting of the transmission properties can be achieved efficiently.

[0024] Alternatively or additionally, the control unit can be configured to determine a value for the transmission characteristic for different (relative) rotations of the primary coil and / or the secondary coil. For example, a value for the transmission characteristic can be determined for different rotation angles of the primary coil and / or the secondary coil. Such a measurement procedure can be carried out, for example, before the start of a charging process. This involves a specific offset between the primary coil and the secondary coil, which should not change during the charging process.

[0025] The rotation information can then be determined based on the measured values ​​of the transmission characteristic for the different (relative) rotations. In particular, the rotation angle for the primary coil and / or for the secondary coil can be selected to achieve an optimal value for the transmission characteristic (e.g., a maximum coupling factor). In this way, the rotation information for controlling the rotary actuator can be determined flexibly and precisely for a specific offset situation.

[0026] The charging device with the primary coil and the device with the secondary coil (especially a vehicle) typically remain in a fixed position during a charging process. Thus, a fixed lateral offset position is typically maintained during a charging process. Nevertheless, the transmission characteristics of the inductive charging system can change (especially deteriorate) during a charging process. In particular, the voltage across an energy storage device being charged typically changes during a charging process, which can alter a transmission characteristic (especially the coupling factor). Alternatively or additionally, a change in the lateral offset position, and thus a change in the value of a transmission characteristic (especially the coupling factor), may occur (e.g., due to the vehicle rolling away).

[0027] The control unit can be configured to repeatedly determine updated rotation information during a charging process, indicating how the primary and / or secondary coils should be rotated to improve a transfer characteristic of the inductive charging system (which may have changed during the charging process). The rotary actuator can then be (repeatedly) controlled based on this updated rotation information. The inductive charging system can thus be repeatedly adjusted to a changing transfer characteristic during a charging process (e.g., periodically at a specific frequency, such as once per minute or more, once every 10 minutes or more, once every 30 minutes or more, or once per hour or more). The inductive charging system can therefore be operated at a (nearly) optimal operating point throughout the entire charging process, further increasing the efficiency of the charging process.

[0028] The control unit can be configured to detect changes in a transmission characteristic of the inductive charging system during a charging process. For example, the value of the transmission characteristic can be checked repeatedly (especially periodically, approximately once per minute or more, once every 10 minutes or more, once every 30 minutes or more, or once per hour or more). This may detect a deterioration in the transmission characteristic (e.g., by 5%, 10%, 20% or more, since the last rotation of the primary and / or secondary coil). In response, updated rotation information can be determined to improve the transmission characteristic. The rotation actuator can then be controlled based on this updated rotation information.This allows for repeated checks during a charging process to determine whether the transmission characteristics of the inductive charging system have deteriorated. The primary and / or secondary coil can then be rotated promptly to improve the transmission characteristics. This further increases the efficiency of the charging process.

[0029] According to another aspect, a primary unit for an inductive charging system is described (e.g., as part of a charging device). The inductive charging system comprises the primary unit and a secondary unit with a secondary coil. The primary unit includes a primary coil configured to generate a magnetic field for transferring energy to the secondary coil.

[0030] Furthermore, the primary unit includes a rotary actuator configured to rotate the primary coil relative to the secondary coil. The primary unit also includes a control unit configured to determine rotation information indicating how the primary coil should be rotated relative to the secondary coil to improve a transmission characteristic of the inductive charging system. The control unit is further configured to actuate the rotary actuator based on this rotation information.

[0031] According to another aspect, a secondary unit for an inductive charging system is described (e.g., as part of a vehicle). The charging system comprises the secondary unit and a primary unit with a primary coil. The secondary unit includes a secondary coil configured to generate a current for charging an energy storage device, depending on a magnetic field generated by the primary coil. The secondary unit also includes a rotary actuator configured to rotate the secondary coil relative to the primary coil. Furthermore, the secondary unit includes a control unit configured to determine rotation information indicating how the secondary coil should be rotated relative to the primary coil to enhance a transfer characteristic of the inductive charging system. The control unit is further configured to actuate the rotary actuator based on this rotation information.

[0032] According to another aspect, a charging device is described (especially for charging the energy storage of a vehicle) which includes the primary unit described in this document.

[0033] According to another aspect, a road motor vehicle (in particular a passenger car or a truck or a bus) is described that includes the secondary unit described in this document.

[0034] According to another aspect, a method for improving (in particular, optimizing) a transmission property of an inductive charging system for charging an energy storage device is described. The charging system comprises a primary coil configured to generate a magnetic field for energy transmission. The charging system also comprises a secondary coil configured to generate a current for charging the energy storage device, depending on the magnetic field. The method can be designed to improve, and in particular optimize, the transmission property of the inductive charging system for a specific offset distance between the primary and secondary coils. During the execution of the method (and optionally during the charging process), the charging device with the primary coil and the device with the secondary coil (in particular, a vehicle) can be connected to the primary coil.of the subsequent charging process) each remain in a fixed position (and in particular maintain a fixed lateral offset position).

[0035] The method comprises determining rotation information indicating how the primary coil and / or the secondary coil (possibly relative to each other) should be rotated to improve the transfer characteristics of the inductive charging system. Furthermore, the method comprises controlling a rotary actuator based on the rotation information, wherein the rotary actuator is configured to rotate the primary coil and / or the secondary coil (in particular relative to each other).

[0036] Another aspect described is a software (SW) program. The SW program can be configured to run on a processor (e.g., on a vehicle's control unit) and thereby execute the procedure described in this document.

[0037] Another aspect describes a storage medium. This storage medium can include a software program configured to run on a processor and thereby execute the procedure described in this document.

[0038] It should be noted that the methods, devices, and systems described in this document can be used both alone and in combination with other methods, devices, and systems described in this document. Furthermore, any aspect of the methods, devices, and systems described in this document can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways.

[0039] The invention will now be described in more detail using exemplary embodiments. Fig. 1 Exemplary components of an inductive charging system for charging the energy storage of a vehicle; Fig. 2a to 2c are exemplary coils for inductive charging; Fig. 2d an exemplary equivalent circuit diagram for an inductive charging system; Fig. 3a a charging system with an exemplary rotatable or tiltable coil; Fig. 3b an exemplary increase in the coupling factor by tilting a coil; and Fig. 4 a flowchart of an exemplary procedure for increasing the coupling factor of an inductive charging system.

[0040] As stated at the outset, this document deals with the provision of a primary unit 110 and / or a secondary unit 120 for an inductive charging system, which enables the highest possible coupling degree even in misaligned situations. In this context, it shows Fig. 2a An exemplary primary coil 111 and an exemplary secondary coil 121, each comprising a coil core 200, in particular a ferrite. The coil cores 200 are each flat to allow for the smallest possible extension of the primary unit 110 and the secondary unit 120 in the z-direction (i.e., along the underbody clearance 130 and along the magnetic transmission path of the inductive charging system, respectively). On the other hand, the flat structure results in a relatively large underbody clearance to be bridged.

[0041] The primary coil 111 generates a magnetic field 250 (referred to in this document as the charging field) which causes a current to be drawn into the secondary coil 121 to charge an energy storage device 103.

[0042] Fig. Figure 2b shows a side view of a coil winding 210 (e.g., of the primary coil 111 or the secondary coil 121). The coil core 200 is typically located on the back side of the coil winding 210 with respect to the transmission path of the inductive charging system. The coil winding 210 typically has a plurality of turns of an electrically conductive conductor 211. The conductor 211 can be designed as a stranded wire with a plurality of insulated individual wires. The coil 111, 121 is typically covered by a cover 220 towards the underbody clearance 130 or towards the transmission path. Fig. 2c shows a top view of the coil winding 210 and the coil core 200 from the direction of the transmission path.

[0043] The inductive coupling system between primary coil 111 and secondary coil 121 can be represented, for example, by a T-equivalent circuit (see Fig. 2d) described or modeled. This model 230 has as transmission parameters or transmission properties 231 the effective inductance L1 of the primary coil 111, the effective inductance L2 of the secondary coil 121 and the coupling factor k (with the mutual inductance). M=k⋅L1L22 The transmission parameters or transmission properties L1, L2, M, k 231 are typically functions of the relative position between primary coil 111 and secondary coil 121, i.e. functions of x, y, z.

[0044] To bridge a relatively large air gap between the primary coil 111 and the secondary coil 121, relatively high currents are typically used through the primary coil 111. This, in conjunction with a corresponding number of turns in the primary coil 111, generates a relatively large magnetic flux, in order to induce a corresponding electrical voltage on the secondary side despite the relatively low coupling degree. The relatively large air gap is primarily due to the underbody clearance 130 of the vehicle 100. To enable sufficient energy transfer despite a relatively low coupling degree or coupling factor, relatively large-area coils 111, 121 are typically used. The coils 111, 121 must be designed such that a certain tolerance exists for translational misalignment between the coils 111, 121 within the inductive charging system.Taking an offset tolerance into account typically leads to a further increase in the size of coils 111, 121. In total, this results in a relatively large amount of material required for coils 111, 121 and a relatively large circuit complexity for controlling coils 111, 121.

[0045] Furthermore, a relatively large air gap volume and a relatively high flux density result in a relatively high effort required to monitor the space between the primary coil 111 and the secondary coil 121 (e.g., for detecting foreign objects and / or for automatic shutdown upon the entry of living objects, etc.). The relatively large dimensions of the coils 111 and 121 and the relatively high flux densities typically mean that the magnetic field 250 decays only relatively slowly with distance from the coils 111 and 121 (thus further increasing the area to be monitored).

[0046] The primary coil 111 and the secondary coil 121 are typically aligned parallel to each other in their basic position. However, due to this parallel alignment of the primary and secondary coils 111 and 121, only the z-component of the magnetic field 250 is used for energy transfer. The components in the y and x directions, on the other hand, do not contribute to energy transfer. The z-component runs perpendicular to the ground from the primary coil 111 to the secondary coil 121. The x and y directions run parallel to the ground between the primary coil 111 and the secondary coil 121.

[0047] This document describes a coil 111, 121 for an inductive charging system, which can be aligned, in particular inclined, depending on the specific offset between the primary coil 111 and the secondary coil 121 of the charging system (e.g., depending on the parking position of a vehicle 100) in order to improve the transmission characteristics 231, in particular the coupling factor k, of the inductive charging system. Depending on the translational positioning of the coils 111, 121 relative to each other, i.e., depending on the offset, the optimal alignment of the coils 111, 121 deviates from parallel coils 111, 121. In particular, a significant improvement in the transmission characteristics 231 of the inductive charging system can be achieved by inclineding at least one of the coils 111, 121.

[0048] Fig. Figure 3a shows an inductive charging system 300 with a primary coil 111 and a secondary coil 121, which are spaced a certain distance 301 apart along the z-axis. The secondary coil 121 can be rotated about the x-axis and / or the y-axis so that the primary coil 111 and the secondary coil 121 are no longer perpendicular to each other. The secondary coil 121 has a secondary axis 332 that is perpendicular to the surface of the secondary coil 121. Furthermore, the primary coil 111 has a primary axis 331 that is perpendicular to the surface of the primary coil 111. By rotating the secondary coil 121, the primary axis 331 and the secondary axis 332 can be made to no longer be parallel to each other.

[0049] Fig. Figure 3a shows the y-axis 302, which runs parallel to the surface of the primary coil 111. A rotation about the x-axis can produce a rotation or tilt angle ϕ 303 relative to the y-axis 302. Alternatively or additionally, a rotation about the y-axis 302 can produce a rotation or tilt angle δ 303 relative to the x-axis (not shown in Figure 3a). Fig. 3a) can be achieved. A rotational offset of the secondary coil 121 relative to the primary coil 111 can thus be effected (by rotation about the x-axis and / or the y-axis) in order to at least partially compensate for a translational offset of the primary coil 111 relative to the secondary coil 121 along the x-axis and / or the y-axis.

[0050] Fig. Figure 3b shows an example of an improvement potential 309 of the coupling factor k, which can be achieved by rotating the primary coil 111 and / or the secondary coil 121 for different offset distances 310. From Fig. 3b shows that in the example shown, an improvement of the coupling factor k by up to 25% is possible.

[0051] A primary unit 110 and / or a secondary unit 120 for the inductive power supply of vehicles 100 and for charging vehicles 100 with an electric drive system is described, which enables the coil alignment of an inductive charging system 300 to be not limited to parallelism, but rather to provide rotation about the x, y, and / or z-axis as an additional degree of freedom to improve the transmission characteristics 231. Rotation about the x, y, and / or z-axis can be adjusted mechanically (by at least one rotary actuator 311). In particular, the primary unit 110 and the secondary unit 120 can comprise one or more rotary actuators 311 configured to rotate the respective coil 111, 121 about the x, y, and / or z-axis. Alternatively or additionally, rotation of the secondary coil 121 can be effected on a vehicle 100 by an adjustment, e.g., by a spring mechanism.A coil 111, 121 can be designed to be rotatable in such a way that the coil 111, 121 continues to conform to a standard for an inductive charging system 300.

[0052] The inductive charging system 300 can include a control unit 312 configured to cause rotation of the primary coil 111 and / or the secondary coil 121 of the inductive charging system 300. In particular, the control unit 312 can be configured to control a rotary actuator 311, which causes rotation of the primary coil 111 and / or the secondary coil 121. Furthermore, the control unit 312 can be configured to determine rotation information about how the primary coil 111 and / or the secondary coil 121 should be rotated to increase the coupling factor k of the inductive charging system 300.

[0053] For example, the control unit 312 can determine offset information about the translational offset between the primary coil 111 and the secondary coil 121. The offset information can, for example, display the offset distance 310 along the x-axis and / or the offset distance 310 along the y-axis. Characteristic data can be provided that, depending on the offset information, indicate rotation information about how the primary coil 111 and / or the secondary coil 121 should be rotated to increase, and in particular maximize, the coupling factor k. The characteristic data can, for example, include a lookup table that displays rotation angles 303 for the primary coil 111 and / or the secondary coil 121 for different offset distances 310 along the x- and / or y-axis. The one or more actuators 311 can then be controlled to set the rotation angles 303 indicated by the characteristic data.

[0054] Alternatively or additionally, the control unit 312 can be configured to determine the rotation information within an iterative process for increasing, and in particular maximizing, the coupling factor k of the inductive charging system 300. For a specific offset situation, the respective coupling factor k of the inductive charging system 300 can be determined for different rotation angles 303 of the primary and / or secondary coil 111, 121. For this purpose, (wireless) communication can take place between the primary unit 110 and the secondary unit 120. The one or more rotation angles 303 for adjusting the primary and / or secondary coil 111, 121 can then be selected, thereby increasing, and in particular maximizing, the coupling factor k.

[0055] Fig.Figure 4 shows a flowchart of an exemplary method 400 for improving a transmission property 231, in particular the coupling factor k, of an inductive charging system 300 for charging an energy storage device 103. The charging system 300 comprises a primary coil 111 (e.g., as part of a primary unit 110 or a charging device or charging station) configured to generate a magnetic field 250 for energy transmission. The inductive charging system 300 also comprises a secondary coil 121 (e.g., as part of a secondary unit 120, in particular within a vehicle 100) configured to generate a current for charging the energy storage device 103, depending on the magnetic field 250.

[0056] Method 400 comprises determining 401 rotation information indicating how the primary coil 111 and / or the secondary coil 121 are to be rotated (particularly relative to each other) to improve the transmission characteristic 231 of the inductive charging system 300. In particular, the rotation information can indicate a rotation angle 303 for a rotation of the primary coil 111 and / or the secondary coil 121. For example, a rotation angle 303 can be indicated by which the primary coil 111 is to be rotated relative to a stationary secondary coil 121, or by which the secondary coil 121 is to be rotated relative to a stationary primary coil 111.

[0057] Furthermore, the method 400 includes controlling 402 at least one rotary actuator 311 depending on the rotation information. The rotary actuator 311 is configured to rotate the primary coil 111 and / or the secondary coil 121 (in particular relative to each other). The rotary actuator 311 can thus rotate the primary coil 111 and / or the secondary coil 121 in such a way that the transmission characteristic 231 of the inductive charging system 300 is improved.

[0058] The measures described in this document for improving the transmission characteristics 231 of an inductive charging system 300 make it possible to modify standardized coil systems in such a way that higher efficiencies of the transmission and of the entire charging system 300 can be achieved. This improvement can also be used to reduce the coil dimensions, thereby saving installation space, material, and costs. Furthermore, the translational offset range in which inductive charging is possible can be increased. In addition, by changing the coil orientation, impedance matching can be achieved even in extreme offset situations, which would not be possible using electronic measures.

[0059] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and the figures are intended only to illustrate the principle of the proposed methods, devices, and systems.

Claims

[1] Inductive charging system (300) for charging an energy storage device (103); wherein the charging system (300) comprises, - a primary coil (111) configured to generate a magnetic field (250) for the transmission of energy; - a secondary coil (121) which is configured to generate a current for charging the energy storage device (103) depending on the magnetic field (250); - a rotary actuator (311) configured to rotate the primary coil (111) and / or the secondary coil (121); and - a control unit (312) that is set up, - to determine rotation information indicating how to rotate the primary coil (111) and / or the secondary coil (121) in order to improve a transmission property (231) of the inductive charging system (300); and - to control the rotary actuator (311) depending on the rotation information. [2] Inductive charging system (300) according to claim 1, wherein - a primary axis (331) of the primary coil (111) runs perpendicular to a coil winding (210) of the primary coil (111); - a secondary axis (332) of the secondary coil (112) runs perpendicular to a coil winding (210) of the secondary coil (121); and - the rotary actuator (311) is set up, - to cause a rotation of the primary coil (111) about the primary axis (331) and / or a change in the orientation of the primary axis (331); and / or - to cause a rotation of the secondary coil (121) around the secondary axis (332) and / or a change in the orientation of the secondary axis (332). [3] Inductive charging system (300) according to claim 2, wherein - in a basic position of the primary coil (111) and the secondary coil (121), the primary axis (331) and the secondary axis (332) run parallel to each other; and - the rotary actuator (311) is set up to rotate the primary coil (111) and / or the secondary coil (121) in such a way that the primary axis (331) and the secondary axis (332) are no longer parallel to each other. [4] Inductive charging system (300) according to one of the preceding claims, wherein - the secondary coil (121) is arranged in a vehicle (100); - the vehicle (100) comprises one or more vehicle actuators, in particular a shock absorber, with which a tilt of the vehicle (100) can be changed; and - the rotary actuator (311) which includes one or more vehicle actuators. [5] Inductive charging system (300) according to one of the preceding claims, wherein the rotary actuator (311) - includes an electrically driven actuator; - is set up to move the primary coil (111) relative to a charging station (110) in which the primary coil (111) is arranged; and / or - is set up to move the secondary coil (121) relative to a device, in particular a vehicle (100), in which the secondary coil (121) and the energy storage device (103) are arranged. [6] Inductive charging system (300) according to one of the preceding claims, wherein the control unit (312) is configured, - To determine offset information with respect to a translational offset distance (310) between the primary coil (111) and the secondary coil (121); and - to determine the rotation information based on the offset information. [7] Inductive charging system (300) according to claim 6, wherein - the control unit (312) is set up to determine the rotation information based on characteristic data; and - the characteristic data for different offset distances (310) each display corresponding rotation information. [8] Inductive charging system (300) according to one of the preceding claims, wherein the control unit (312) is configured, - to determine a value of the transmission property (231) for each of the different rotations of the primary coil (111) and / or the secondary coil (121) relative to each other; and - to determine the rotation information based on the values ​​of the transmission property (231) for the different rotations. [9] Inductive charging system (300) according to one of the preceding claims, wherein the control unit (312) is configured to repeatedly during a charging process, - to determine updated rotation information indicating how to rotate the primary coil (111) and / or the secondary coil (121) to improve a transmission property (231) of the inductive charging system (300); and - to control the rotary actuator (311) depending on the updated rotation information. [10] Inductive charging system (300) according to claim 9, wherein the control unit (312) is configured, - to detect that a transmission property (231) of the inductive charging system (300) has changed during a charging process; and - in response to this, to determine updated rotation information and to control the rotation actuator (311) depending on the updated rotation information. [11] Inductive charging system (300) according to one of the preceding claims, wherein - the primary coil (111) and / or the secondary coil (121) each comprise a circular coil and / or a double D coil; and / or - either the primary coil (111) but not the secondary coil (121) or the secondary coil (121) but not the primary coil (111) can be rotated; and / or - the transmission property (231) includes a coupling factor between the primary coil (111) and the secondary coil (121); and / or - the rotation information indicates a rotation angle (303) by which the primary coil (111) and / or the secondary coil (121) are to be rotated. [12] Primary unit (110) for an inductive charging system (300) comprising the primary unit (110) and a secondary unit (120) with a secondary coil (121); wherein the primary unit (110) comprises, - a primary coil (111) configured to generate a magnetic field (250) for transferring energy to the secondary coil (121); - a rotary actuator (311) configured to rotate the primary coil (111) relative to the secondary coil (121); and - a control unit (312) that is set up, - to determine rotation information indicating how the primary coil (111) is to be rotated relative to the secondary coil (121) in order to improve a transmission property (231) of the inductive charging system (300); and - to control the rotary actuator (311) depending on the rotation information. [13] Secondary unit (120) for an inductive charging system (300) comprising the secondary unit (120) and a primary unit (110) with a primary coil (111); wherein the secondary unit (120) comprises, - a secondary coil (121) which is configured to generate a current for charging an energy storage device (103) depending on a magnetic field (250) generated by the primary coil (111); - a rotary actuator (311) configured to rotate the secondary coil (121) relative to the primary coil (111); and - a control unit (312) that is set up, - to determine rotation information indicating how the secondary coil (121) is to be rotated relative to the primary coil (111) in order to increase a transmission property (231) of the inductive charging system (300); and - to control the rotary actuator (311) depending on the rotation information. [14] Method (400) for improving a transmission property (231) of an inductive charging system (300) for charging an energy storage device (103); wherein the charging system (300) comprises a primary coil (111) configured to generate a magnetic field (250) for energy transmission; and wherein the inductive charging system (300) comprises a secondary coil (121) configured to generate a current for charging the energy storage device (103) depending on the magnetic field (250); wherein the method (400) comprises, - Determining (401) a rotation information indicating how to rotate the primary coil (111) and / or the secondary coil (121) to improve the transmission characteristic (231) of the inductive charging system (300); and - Controlling (402) a rotary actuator (311) depending on the rotation information; wherein the rotary actuator (311) is configured to rotate the primary coil (111) and / or the secondary coil (121).

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