Circuit device for reactive power compensation in an inductive charging apparatus, inductive charging apparatus and system for inductive energy transmission

Abstract

The invention relates to a circuit device for reactive power compensation in an inductive charging apparatus, to an inductive charging apparatus and to a system for inductive energy transmission. The circuit device comprises two input connections for connecting a voltage supply unit or a voltage consumer unit; two output connections for connecting a first or second energy coil; a compensation circuit unit having a series capacitor arranged between an input connection and an output connection and / or a parallel capacitor arranged between the two input connections or the two output connections; and at least one switching unit arranged in the compensation circuit unit for disconnecting the electrical connection between said input connection and said output connection and for interrupting a flow of current through an energy coil connected to the output connections.

Description

[0001] Circuit device for reactive power compensation in an inductive charging device, inductive charging device and system for inductive energy transmission

[0002] The invention relates to a circuit device for reactive power compensation in an inductive charging device. The invention further relates to an inductive charging device, in particular for a vehicle charging system, and a system for inductive energy transmission.

[0003] A system for inductive energy transfer typically comprises a stationary inductive charging device (hereinafter also referred to as an "inductive charging device" or "inductive charging device") and a mobile inductive charging device. During charging, an energy coil (hereinafter also referred to as the "first energy coil") of one of the inductive charging devices acts as a primary coil, and the energy coil (hereinafter also referred to as the "second energy coil") of the other inductive charging device acts as a secondary coil. The "energy coils" are also referred to as "power coils," "transmission coils," or "power transfer coils."

[0004] Such systems are typically used for inductive energy transfer to a mobile application, for example, a motor vehicle, where the mobile application includes the mobile induction charging device. In mobile applications, the energy coil of the mobile induction charging device is usually the secondary coil during charging operation. For inductive energy transfer, the primary coil generates an alternating magnetic field, which induces a voltage in the secondary coil. To enable inductive energy transfer and increase the efficiency of inductive energy transfer, the primary coil and the secondary coil, and thus the energy coils of the induction charging devices, must be positioned accordingly relative to one another.

[0005] DE 102022203489 A1 discloses a system for inductive energy transmission, particularly for a mobile application, comprising a stationary induction charging device with a stationary energy coil and a mobile induction charging device with a mobile energy coil. Precise and robust detection of the relative position of the energy coils to one another is achieved with a positioning device that has four transmitting coils in one of the induction charging devices and at least one receiver in the other induction charging device. The transmitting coils generate distinguishable positioning fields that interact with the at least one receiver. The ratio of the positioning fields is used to detect whether the energy coils overlap.

[0006] DE 102022120691 A1 discloses an inductive charging device for a vehicle charging system comprising a power transmission winding, at least one flux guide element, and at least one positioning signal winding. The positioning signal winding is designed as a solenoid with a winding axis in the vehicle's longitudinal direction or the desired vehicle longitudinal direction, and the flux guide element is suitable for guiding a magnetic field during a power transmission process that takes place between another inductive charging device and the power transmission winding. The positioning signal winding encloses at least one of the at least one flux guide elements and the power transmission winding.

[0007] DE 102022107568 A1 discloses an inductive charging device for a vehicle charging system comprising a power transmission winding and at least one flux guide element, and comprising at least one first sensor winding and a second sensor winding. The flux guide element is suitable for guiding a magnetic field during a power transmission that takes place between another inductive charging device and the power transmission winding, and the first sensor winding and the second sensor winding are arranged around at least one of the at least one flux guide element. A voltage is induced in the sensor windings by the magnetic field of a positioning signal winding. This voltage is proportional to the component of the magnetic field that is perpendicular to the respective radial longitudinal direction of the sensor winding. Using these voltages, the position of the vehicle relative to the inductive charging device can be determined.

[0008] The present invention is based on the object of improving the accuracy of positioning.

[0009] According to one aspect of the present invention, a circuit device for reactive power compensation in an inductive charging device is provided, the circuit device comprising: two input terminals for connecting a voltage supply unit or a voltage collector unit; two output terminals for connecting a first or second energy coil; a compensation circuit unit with a serial capacitance arranged between an input terminal and an output terminal and / or a parallel capacitance arranged between the two input terminals or the two output terminals; and at least one switching unit arranged in the compensation circuit unit for breaking the electrical connection between this input terminal and this output terminal and interrupting a current flow through an energy coil connected to the output terminals.According to a further aspect of the present invention, an inductive charging device is provided, comprising: a circuit device according to the present invention; a voltage supply unit or voltage pickup unit connected to the two input terminals of the circuit device; a first or second energy coil connected to the two output terminals of the circuit device; and a positioning device for detecting the relative positioning of the energy coils to one another.

[0010] According to a further aspect of the present invention, a system for inductive energy transmission is provided with a stationary inductive charging device (hereinafter also referred to as "Ground Assembly" (GA)) according to the present invention and a mobile inductive charging device (hereinafter also referred to as "Vehicle Assembly" (VA)) according to the present invention.

[0011] Preferred embodiments of the invention are defined in the dependent claims. It is understood that the claimed inductive charging device and the claimed system for inductive energy transfer have similar and / or identical preferred embodiments to the claimed circuit device, in particular as defined in the dependent claims and as disclosed herein.

[0012] The inventors have recognized that by integrating one or more transmitting coils of the positioning device (hereinafter also referred to as a "differential inductive positioning system" (DIPS)) for generating positioning magnetic fields into the inductive charging device, a mutual inductance arises between these transmitting coils and the respective energy coil of the inductive charging device. This magnetic coupling induces a voltage in the energy coil during operation of the transmitting coils. Due to the design of the compensation circuit unit, which generally comprises inductive and / or capacitive components and can form an oscillating circuit, a current also flows there, whereby a current flow can possibly occur even without compensation. This current, in turn, builds up a magnetic field that influences the original field of the transmitting coils through superposition.

[0013] The described effect occurs particularly in stationary inductive charging devices, in which the transmitting coils are preferably provided. However, a comparable effect can also occur in mobile inductive charging devices due to the design of the compensation circuit unit generally used therein. An oscillating circuit can also arise there, which can lead to a current flow in the energy coil if, for example, a passive rectifier is connected directly to the coil and the induced voltage by the positioning coils exceeds the threshold voltage of the rectifier diodes. Receiving coils of the positioning device for detecting a positioning magnetic field of the mobile inductive charging device thus have a mutual inductance of the corresponding energy coil.In the context of the present invention, the term “vehicle” should be understood generally as any mobile application and thus includes not only motor vehicles, but also, for example, industrial trucks, robots, forklifts, etc.

[0014] In addition, the coils of the stationary inductive charging device form a mutual inductance with the coils of the mobile inductive charging device, and vice versa. This ultimately creates a matrix of mutual inductances between all the coils. The switching unit provided according to the invention between an input terminal and an output terminal of the circuit device can break the electrical connection between this input terminal and this output terminal, thereby interrupting the current flow through a power coil connected to the output terminals.In a positioning operation in which one or more transmit coils of the positioning device of an inductive charging device each generate a positioning magnetic field and one or more receive coils of the positioning device of another inductive charging device detect a positioning magnetic field, a current flow in one or both energy coils can be prevented in a simple but efficient manner, which would cause the described interference with the positioning magnetic fields. Positioning accuracy can thus be improved.

[0015] Compensation circuit units for reactive power compensation are also generally known in inductive charging devices and can be designed in different ways. In a preferred embodiment, the compensation circuit unit has a parallel capacitance arranged between the two input terminals or the two output terminals and one or two serial capacitances arranged between an input terminal and an output terminal. In another preferred embodiment, the compensation circuit unit has one or two serial inductances arranged between an input terminal and an output terminal. The specific structure of the compensation circuit unit depends, among other things, on the desired behavior of the energy transmission system, for example, whether a constant voltage should be provided by the energy transmission system.Depending on the design of the compensation, different behaviors can be achieved. Furthermore, the design may also depend on how many degrees of freedom are available or required in the design. In a preferred design, LCC compensation is used.

[0016] The switching unit can be arranged at different locations. In a preferred embodiment, the at least one switching unit is arranged between an input terminal and an output terminal, in particular in series with the parallel capacitance and / or in series with the serial capacitance. By opening the switching unit, the unwanted current flow through the compensation circuit unit can be blocked quickly and efficiently.

[0017] The switching unit can also be designed differently and implemented using different components. For example, the at least one switching unit can comprise a transistor (in particular at least one MOSFET, Si-MOSFET, or SiC-MOSFET), a relay, a triac, or a thyristor. Other implementations are also possible.

[0018] Preferably, the at least one switching unit can have two anti-serial MOSFETs, in particular Si or SiC MOSFETs, connected in series, with a diode connected in parallel to each respective MOSFET. Alternatively, the at least one switching unit can have a parallel connection of two MOSFET circuits, each of which has two anti-serial MOSFETs, in particular Si or SiC MOSFETs, connected in series, with a diode connected in parallel to each respective MOSFET. The specific design of the switching unit depends, among other things, on the desired requirements. The advantage of using SiC MOSFETs is that they have a high dielectric strength and may not be destroyed in the event of a fault. Parallel paths are advantageous, for example, when the current during energy transmission is very high, since this allows the current to be distributed among the MOSFETs and reduces heat generation.The circuit device preferably further comprises a control unit for controlling the at least one switching unit such that the at least one switching unit is closed when an energy coil connected to the output terminals is in an energy transmission mode, in which it inductively transmits or receives energy. In particular, the control is carried out such that the at least one switching unit is only closed when an energy coil connected to the output terminals is in an energy transmission mode. The control unit preferably also controls the operation of the energy transmission and the positioning or knows the respective operating states of the energy transmission device and the positioning device, which are controlled, for example, by their own or a common control unit, in order to be able to carry out the appropriate control of the switching unit.For this purpose, for example, in a preferred embodiment, it is provided that the control unit is designed to receive and / or determine operating information which contains information as to whether the energy coil is in energy transmission mode.

[0019] In a preferred embodiment, the control unit comprises a voltage sensor for determining the operating information by measuring a voltage across the at least one switching unit. This makes it possible to detect whether energy transfer mode is present, for example, by checking whether this voltage exceeds a threshold. If the voltage falls below this threshold, it is assumed that energy transfer mode is not present, but rather, for example, positioning mode is present.

[0020] In a further embodiment, the control unit comprises a voltage supply unit and a gate driver unit for controlling a gate of at least one transistor. By appropriately controlling the gate of the at least one transistor (e.g., MOSFETs) of the switching unit, the switching unit can be controlled (i.e., opened and closed) quickly and easily.

[0021] The circuit device according to the invention is used in particular in an inductive charging device for a vehicle charging system, in which a voltage supply unit or a voltage pickup unit is connected to the two input terminals of the circuit device, in which a first or second energy coil is connected to the two output terminals of the circuit device, and which has a positioning device for detecting the relative positioning of the energy coils to one another. Embodiments of such an inductive charging device (without the circuit device according to the invention) in which the circuit device according to the invention can be used are known, for example, from the aforementioned DE 102022203489 A1 and DE 102022120691 A1.

[0022] The inductive charging device can be a stationary inductive charging device for mounting on and / or in a floor surface, wherein the positioning device has at least one transmitting coil and / or a positioning signal coil for generating a positioning magnetic field, in particular during a positioning operation. The at least one transmitting coil can be configured, for example, like the transmitting coils known from DE 102022203489 A1 for generating distinguishable positioning fields. The positioning signal coil can be configured like the positioning signal winding known from DE 102022120691 A1 (e.g., as a solenoid with a winding axis in the vehicle's longitudinal direction or the desired vehicle's longitudinal direction) for generating and transmitting a positioning signal during a positioning process.The inductive charging device can alternatively be a mobile inductive charging device for mounting on and / or in a vehicle, wherein the positioning device has at least one receiving coil for detecting a positioning magnetic field, particularly during positioning operation. The at least one receiving coil can be configured, for example, like the sensor coil known from DE 102022120691 A1. For example, a first sensor winding with a first radial longitudinal direction and a second sensor winding with a second radial longitudinal direction can be provided.

[0023] In one embodiment of the inductive charging device, the circuit device comprises a control unit for controlling the at least one switching unit such that the at least one switching unit is open when the positioning device is in a positioning mode, in which the relative positioning of the energy coils to one another is detected, and the energy coils are not in an energy transmission mode, in which they inductively transmit energy. This ensures that no interference can be generated during positioning mode by voltages induced in the energy coil(s).

[0024] In a further embodiment of the inductive charging device, it is provided that the voltage supply unit or the voltage pickup unit each comprise a converter unit and a converter control unit, wherein the converter control unit is configured to interrupt a current flow through an energy coil connected to the output terminals, in particular when the positioning device is in a positioning mode in which the relative positioning of the energy coils to one another is detected, and energy coils are not in an energy transmission mode in which they inductively transmit energy. This embodiment also ensures that no interference can be generated during positioning mode by voltages induced in the energy coil(s).

[0025] In a further embodiment, the first power coil and / or the second power coil each comprise at least two partial coils, and each partial coil is connected to the output terminals of a separate circuit device for reactive power compensation. A separate reactive power compensation device can thus be provided for each partial coil (e.g., with three partial coils for a three-phase system), so that a current flow through a partial coil connected to the output terminals can be interrupted separately for each partial coil.

[0026] According to a further aspect of the present invention, an inductive charging device is provided comprising: i) a voltage supply unit and a first energy coil having at least two partial coils or ii) a voltage pickup unit and a second energy coil having at least two partial coils; a positioning device for detecting the relative positioning of the energy coils to one another; and at least one switching unit for breaking the electrical connection i) between the voltage supply unit and the first energy coil or ii) between the voltage pickup unit and the second energy coil or iii) between the partial coils of the first energy coil or the second energy coil and for interrupting a current flow through the first energy coil or the second energy coil.

[0027] The present invention can also be advantageously used in embodiments of the inductive charging device without a compensation circuit unit for reactive power compensation. In particular, if the energy coil has two (or more) partial coils, especially partial coils connected in parallel, the problems described above can occur even without such a compensation circuit unit and lead to an undesired current flow. This current, in turn, builds up a magnetic field that influences the original field of the transmitting coils through superposition.

[0028] 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 on their own, without departing from the scope of the present invention.

[0029] Embodiments of the invention are illustrated in the following drawings and explained in more detail in the following description, wherein like reference numerals refer to like or similar or functionally identical components. They show:

[0030] Fig. 1 is a highly simplified representation of a vehicle with an inductive charging device;

[0031] Fig. 2 is a sectional view of an inductive charging device for a vehicle charging system;

[0032] Fig. 3 is a plan view of an inductive charging device according to the invention with a near-positioning transmitter and a remote-positioning transmitter;

[0033] Fig. 4 is a plan view of an alternative inductive charging device according to the invention with a near-positioning transmitter and a remote-positioning transmitter; Fig. 5 is a flat coil as a near-positioning transmitter for a near-positioning transmitter;

[0034] Fig. 6 shows an inductive charging device with a positioning receiving device for a vehicle charging system according to the invention;

[0035] Fig. 7 shows an inductive charging device with a positioning receiving device for a vehicle charging system according to the invention;

[0036] Fig. 8 shows a vehicle during a positioning process with a vehicle charging system according to the invention;

[0037] Fig. 9 shows a known circuit device for reactive power compensation in a stationary inductive charging device;

[0038] Fig. 10 shows a known circuit device for reactive power compensation in a mobile inductive charging device;

[0039] Fig. 11 is a schematic representation of another embodiment of the inductive charging device;

[0040] Fig. 12 is a schematic representation of another embodiment of the inductive charging device;

[0041] Fig. 13 shows an embodiment of a circuit device according to the invention for reactive power compensation; Fig. 14 shows a further embodiment of a circuit device according to the invention for reactive power compensation;

[0042] Fig. 15-22 exemplary embodiments of a switching unit for a switching device according to the invention;

[0043] Fig. 23 shows an embodiment of the circuit device according to the invention with a compensation circuit unit without parallel capacitance;

[0044] Fig. 24 shows a further embodiment of the circuit device according to the invention with a compensation circuit unit without parallel capacitance;

[0045] Fig. 25 shows an embodiment of a circuit device according to the invention with control;

[0046] Fig. 26 shows a further embodiment of a circuit device according to the invention with control;

[0047] Fig. 27 shows an embodiment of an energy coil with two parallel energy coil windings;

[0048] Fig. 28 shows an embodiment of a circuit device according to the invention for an embodiment of the energy coil shown in Fig. 27; Fig. 29 shows a further embodiment of a circuit device according to the invention with an energy coil compensated in series on the secondary side;

[0049] Fig. 30 shows an embodiment of an inductive stationary charging device according to the invention without a compensation circuit unit for reactive power compensation; and

[0050] Fig. 31 shows an embodiment of a mobile inductive charging device according to the invention without a compensation circuit unit for reactive power compensation.

[0051] Fig. 1 shows a mobile inductive charging device 1a, which is arranged on a vehicle 2 with an energy storage device 3 and 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, thereby charging the energy storage device of the vehicle 3.

[0052] The mobile inductive charging device 1a and the stationary inductive charging device 1b together form or are part of a vehicle charging system 8. In principle, it is also possible to operate the vehicle charging system 8 bidirectionally. In this case, energy can be temporarily transferred from the mobile inductive charging device 1a to the stationary inductive charging device 1b. The stationary inductive charging device 1b arranged on the subsurface 35 in Fig. 1 can alternatively be arranged sunk into the roadway (not shown here). In a sunk arrangement, the inductive charging device 1b can be covered by certain layers of the roadway or can be flush with the road surface. Fig. 2 shows a lateral section through an inductive charging device 1, 1a, which includes several flux guide elements 5 and an energy transmission winding 4 (energy coil) and is mounted on a vehicle 2.A corresponding arrangement exists for a stationary inductive charging device 1b, except that it is arranged on a surface instead of on a vehicle 2 (not shown).

[0053] Fig. 3 shows a plan view of an inductive charging device according to the invention, in which the circuit device according to the invention can be used, with a near-positioning transmitter NAH-POS and a far-positioning transmitter FERN-POS. The near-positioning transmitter NAH-POS is implemented here in the form of four near-positioning windings 13 (transmitting coils), but can also be implemented with more or fewer transmitting windings. The remote-positioning transmitter FERN-POS is implemented here as a solenoid (positioning signal winding). During a positioning process, the remote-positioning transmitter FERN-POS transmits a far-positioning signal FERN-SIG in the form of an alternating magnetic field. During a positioning process, the near-positioning transmitter NAHPOS transmits several near-positioning signals NAH-SIG in the form of alternating magnetic fields, which differ, for example, in frequency.

[0054] Fig. 4 shows a plan view of an alternative inductive charging device according to the invention, in which the circuit device according to the invention can be used, with a near-positioning transmitter NAH-POS and a remote-positioning transmitter FERN-POS. Here, too, the near-positioning transmitter NAH-POS is implemented as four near-transmission windings 13, and the remote-positioning transmitter FERN-POS as a solenoid. This embodiment shows an alternative arrangement of the flux guide elements 5. Furthermore, the remote-positioning signal winding 41 (positioning signal coil) does not run centrally through the center of the inductive charging device 1, but is shifted toward an edge.

[0055] Fig. 5 shows a near-transmitting winding 13, which is designed as a flat coil.

[0056] Fig. 6 shows a further inductive charging device 1, which has a positioning receiving device with two sensor windings 9a and 9b (receiving coils), which are part of a sensor device. This can be a mobile inductive charging device 1a or a stationary inductive charging device 1b. In the present embodiment, eight flux guiding elements 5 are shown, which are arranged radially around the center 7 of the energy transmission winding 4 in the plane. However, there can also be more or fewer flux guiding elements. Between the flux guiding elements 5 are narrow gaps 27. The gaps also run radially around the center 7, thus the gaps run approximately in the main direction of the magnetic field lines (here three magnetic field lines 14 are symbolically indicated), which develop during an energy transmission in the

[0057] The flux-guiding elements 5 are adjusted. The energy transmission winding 4, which is concealed by the flux-guiding elements 5 in the plan view, is indicated by dashed lines. The energy transmission winding 4 is a flat coil here. The sensor windings are designed as solenoids, also called cylindrical coils.

[0058] The first sensor winding 9a here runs around two flux guide elements 5, which are diagonally opposite one another with respect to the center 7 of the energy transmission coil 4. The second sensor winding 9b is correspondingly wound around two further flux guide elements 5, which are also diagonally opposite one another with respect to the center 7. The first sensor winding 9a is arranged axially symmetrically to the second sensor winding 9b with respect to the vehicle's longitudinal direction 6. The first sensor winding 9a and the second sensor winding 9b intersect at least approximately in the center 7 of the energy transmission coil 4. The first sensor winding 9a has a first radial longitudinal direction 11a, and the second sensor winding 9b has a second radial longitudinal direction 11b. The angle 15 between the first radial longitudinal direction 11a and the vehicle's longitudinal direction 6 is at least approximately the same size as the angle 16 between the second radial longitudinal direction 11b and the vehicle's longitudinal direction 6.

[0059] During the charging process, the vehicle 2 is positioned above the stationary inductive charging device 1b, and energy is transferred to the inductive charging device 1a. The flux guiding elements 5 perform the function of flux guiding. In the charging state, the field lines of the magnetic field run approximately radially within them. 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, only relatively little or no voltage is induced in the first sensor winding 9a and the second sensor winding 9b. This is advantageous, since the high power levels of the energy transfer and thus the high flux densities could otherwise easily lead to the sensor windings being destroyed. Additional effort to prevent the arrangement from being destroyed is therefore unnecessary.

[0060] Fig. 7 shows a plan view of a further embodiment of an inductive charging device 1 according to the invention, in which the circuit device according to the invention can be used. Here, four sensor windings 9a, 9b, 9c, 9d with four radial longitudinal directions 11a, 11b, 11c, 11d are present. However, there can also be more or fewer sensor windings. Each sensor winding is arranged around a different flux guide element 5. Two of the flux guide elements are located diagonally opposite each other with respect to the center 7 of the energy transmission coil 4. Together, the four sensor windings 9a, 9b, 9c, 9d again form a cross-shaped arrangement. An advantage over the arrangement in Fig. 6 is that the area around the center 7 of the energy transmission coil 4 is designed without a sensor winding 9. This means that mechanically necessary support elements (not shown) can still be arranged here.

[0061] The inductive charging device according to the invention shown in Fig. 3 and Fig. 4 and the further inductive charging device according to Fig. 6 and Fig. 7 can be part of a vehicle charging system 8 according to the invention. In this case, one positioning receiving device can receive signals from both the near-positioning transmitter NAH-POS and the remote-positioning transmitter FERN-POS. This is advantageous because one positioning receiving device can support two different positioning methods that function optimally at two different distance ranges.

[0062] Fig. 8 a) shows a vehicle 2 with a vehicle longitudinal direction 6 and with a mobile inductive charging device 1a during a positioning process above a stationary inductive charging device 1b with a desired vehicle longitudinal direction 6a. The vehicle 2 drives directly towards the stationary inductive charging device 1b and the desired vehicle longitudinal direction 6a is thus the same as the vehicle longitudinal direction 6. In addition to the energy transmission winding (not shown), the mobile inductive charging device 1a also contains a remote positioning signal winding 41 and four short-range transmission windings 13. The remote positioning signal winding 41 has a winding axis 36 and a radial longitudinal direction 11. The four short-range transmission windings 13 have winding axes perpendicular to the ground. The stationary inductive charging device 1b has, in addition to the energy transmission winding (not shown), two sensor windings 9a and 9b.Both sensor windings 9a and 9b each have a radial longitudinal direction 11a and 11b. Both sensor windings 9a and 9b are arranged symmetrically to the desired vehicle longitudinal direction 6a. This arrangement of the windings is particularly advantageous for positioning. The remote positioning signal winding 41 generates a fairly homogeneous magnetic field. A voltage is induced in the sensor windings 9a and 9b by the magnetic field of the remote positioning signal winding 41. If the vehicle moves exactly perpendicularly toward the stationary inductive charging device 1b, as shown in the left-hand sketch, an equal voltage is induced in both sensor windings 9a and 9b during the remote positioning process FERN_V. From a certain distance, the near positioning process NAH_V is used, and the near positioning signals NAH-SIG transmitted by the near transmission windings 13 are evaluated.

[0063] Fig. 8 b) shows an embodiment in which the remote positioning signal winding 41 and the four short-range transmission windings 13 are arranged in the stationary inductive charging device 1 b and the sensor windings 9a and 9b are arranged in the mobile inductive charging device 1a. The mode of operation of this embodiment is otherwise identical to that described above with reference to Fig. 8 a). Shown here is a case in which the vehicle 2 does not approach the stationary inductive charging device 1b perpendicularly, but deviates from it at an angle of approximately 45°. The vehicle's longitudinal direction 6 and the connecting line between the stationary inductive charging device 1b and the mobile inductive charging device 1a are thus at a directional deviation angle of 45° to one another. In this case, the remote positioning signal winding 41 generates a magnetic field which is perpendicular to the first sensor winding 9a.Here, a maximum voltage is induced in the first sensor winding 9a during the remote positioning process FERN_V. The magnetic field generated by the remote positioning signal winding 41 is also approximately parallel to the second sensor winding 9b. Here, a minimal or no voltage is induced during the remote positioning process FERN_V. Here, too, the near positioning process NAH_V can take over from a certain distance. With the Differential Inductive Positioning System (DIPS) for an inductive charging system described in Figs. 1 to 8, a specific positioning magnetic field is thus generated by arranging several transmitting coils on the stationary inductive charging device (also referred to as Ground Assembly (GA)) in order to ensure interoperability between the GA and the mobile inductive charging device (also referred to as Vehicle Assembly (VA)) from different manufacturers.Due to the coupling between the transmitting coils and the one or more GA power coils (i.e., the one or more energy coils of the stationary inductive charging device), the induced voltage in the GA power coils, which is excited by the transmitting coils, potentially generates an induced current in the GA power coils. The magnetic field generated by this current superimposes the positioning magnetic field, thereby influencing the distribution of the positioning magnetic field and thus the evaluation of the positioning field in the VA. The same problem also exists between the transmitting coils and the one or more VA power coils (i.e., the one or more energy coils of the mobile inductive charging device). Here, currents can also be induced in the VA power coil, which in turn influence the positioning magnetic field.

[0064] The state of the art for inductive charging systems includes, among others, the applicable standards from SAE J2954, ISO 19363, and IEC 61908. These are harmonized and provide so-called reference designs (mechanical description of a coil design and electrical description of the transmission path) as a guide for development and product testing. A circuit device for reactive power compensation in the GA according to SAE J2954 with parallel compensation is shown in Fig. 9. A circuit device for reactive power compensation in the VA according to SAE J2954 with parallel compensation is shown in Fig. 10. The circuit devices shown in Fig. 9 and Fig. 10 comprise, by way of example, a compensation circuit unit with a capacitor C2 connected in parallel to the respective transmission coil LGA (for the GA) or LVA (for the VA), as well as two capacitors C1a, C1b connected in series with it.Even if it can be assumed that such parallel compensation is mostly used for reactive power compensation, other circuit devices are also conceivable.

[0065] Fig. 11 shows a simplified schematic representation of another embodiment of the inductive charging device 1b, which, in addition to the energy coil 4, has both a positioning signal winding 41 and four transmitting coils 13. The positioning signal winding 41 is arranged as a solenoid in the central region around the energy coil 4 and the flux guiding elements 5. The four transmitting coils 13 are arranged in the four corners above or below the energy coil 4. Further details of the inductive charging device 1b shown in Figs. 3, 4 and 11 are disclosed in DE 102022203489 A1 and DE 102022120691 A1, to which reference is hereby explicitly made and the disclosure of which is hereby incorporated into the present application by this reference.

[0066] Fig. 12 shows a schematic representation of a further embodiment of the inductive charging device 1a, which, in addition to the energy coil 4, has two sensor windings 9a, 9b. Further details of the inductive charging device 1a shown in Figs. 6, 7 and 12 are disclosed in DE 102022107568 A1, to which reference is hereby explicitly made and the disclosure of which is hereby incorporated into the present application by this reference. By integrating the DIPS, i.e. in particular the positioning device of the GA with the transmitting coils and / or the positioning signal coil (cf., for example, Figs. 3, 4 and 11), into the existing circuit device for energy transmission, a mutual inductance is created between the coils of the DIPS, i.e. the near-transmitting windings 13 (transmitting coils) and / or the far-positioning signal winding 41, and the energy transmission winding 4 (energy coil).This magnetic coupling induces a voltage in the power coil 4 during operation of the DIPS coils 13, 41, resulting in a current flow. This current, in turn, builds up a magnetic field that influences the original field of the DIPS coils through superposition.

[0067] The same effect is created by the resonant circuit with the parallel capacitance C2 of the circuit device for the VA shown in Fig. 10. Each of the two sensor windings 9a, 9b (see, for example, Figs. 6, 7, and 12), which are part of the VA positioning device, has a mutual inductance with the VA's power coil. At the same time, all coils of the GA also form a mutual inductance with all coils of the VA, and vice versa. This creates a matrix of mutual inductances with all coils among themselves.

[0068] According to the invention, by separating the resonant circuit in the GA, a current flow in the GA energy coil caused by the positioning magnetic field is avoided. Similarly, by separating the resonant circuit in the VA, a current flow in the VA energy coil caused by the positioning magnetic field is avoided.

[0069] Fig. 13 shows an embodiment of a circuit device 100 according to the invention for reactive power compensation in an inductive charging device, which can be used in particular for the stationary inductive charging device (GA). The circuit device 100 comprises two input terminals 101, 102 for connecting a voltage supply unit 150, in this case a power factor correction circuit (PFC) 151 with a downstream inverter circuit 152. The circuit device 100 further comprises two output terminals 103, 104 for connecting a first energy coil LGA.

[0070] A compensation circuit unit 110 is arranged between the input and output terminals. This can be configured in different ways, with a serial capacitance arranged between an input terminal and an output terminal and / or a parallel capacitance arranged between the two input terminals or the two output terminals. In the exemplary embodiment shown, the compensation circuit unit 110 has a parallel capacitance C2 arranged between the input terminals 101, 102, a first series capacitance C1a arranged between a first input terminal 101 and a first output terminal 103, and a second series capacitance C1b arranged between a second input terminal 102 and a second output terminal 104.

[0071] Furthermore, according to the invention, at least one switching unit 120 is provided between an input terminal and an output terminal for breaking the electrical connection between this input terminal and this output terminal and interrupting a current flow through the energy coil LGA connected to the output terminals. This switching unit(s) is (are) shown only symbolically as an "X" in Fig. 13, in particular to show at which positions of the circuit device 100 a switching unit can be provided according to the invention to interrupt the desired current flow. In principle, a single switching unit is sufficient, but two or more switching units can also be provided.In one embodiment, a complex resistor JXGA / 2 in the form of a series inductance is (optionally) additionally provided between the inverter circuit 152 and the input terminals 101, 102 of the circuit device 100. In this embodiment, a switching unit could also be provided in series with such a complex resistor, wherein the switching unit should break the current path via the parallel capacitance C2 and should therefore preferably be located behind C2, as shown in Fig. 13.

[0072] If the inverter circuit 152 is controlled such that no current flows through the loop with the capacitors C1a, C1b and the power coil LGA, a switching unit 121 (shown in dashed lines in Fig. 13) can alternatively or additionally be arranged at other locations, e.g., in the current path with the capacitor C2. Such control of the inverter circuit 152 is also preferred if the compensation circuit does not have a parallel capacitor C2.

[0073] Fig. 14 shows a further embodiment of a circuit device 200 according to the invention for reactive power compensation in an inductive charging device, which can be used in particular for the mobile inductive charging device (VA). The circuit device 200 comprises two input terminals 201, 202 for connecting a voltage pickup unit 250, in this case a battery 251 with an upstream rectifier circuit 252. The circuit device 200 further comprises two output terminals 203, 204 for connecting a second energy coil LVA.

[0074] A compensation circuit unit 210 is arranged between the input and output terminals. This can be configured in various ways, with a serial capacitance arranged between an input terminal and an output terminal and / or a parallel capacitance arranged between the two input terminals or the two output terminals. In the exemplary embodiment shown, the compensation circuit unit 210 has a parallel capacitance C2 arranged between the input terminals 201, 202, a first series capacitance C1a arranged between a first input terminal 201 and a first output terminal 203, and a second series capacitance C1b arranged between a second input terminal 202 and a second output terminal 204.

[0075] Furthermore, according to the invention, at least one switching unit 220 is provided between an input terminal and an output terminal for breaking the electrical connection between this input terminal and this output terminal and interrupting a current flow through the energy coil LVA connected to the output terminals. This switching unit(s) is (are) shown only symbolically as an "X" in Fig. 14, in particular to show at which positions of the circuit device 200 a switching unit can be provided according to the invention to interrupt the desired current flow. In principle, a single switching unit is sufficient, but two or more switching units can also be provided.

[0076] In one embodiment, a complex resistor JXVA / 2 in the form of a series inductance is (optionally) additionally provided between the rectifier circuit 252 and the input terminals 201, 202 of the circuit device 200. In this embodiment, a switching unit could also be provided in series with such a complex resistor. Here, too, the switching unit is intended to separate the current path via the parallel capacitor C2 and is therefore preferably located upstream of C2, as shown in Fig. 14. The switching units can be implemented in different ways. Figs. 15 to 22 show some exemplary embodiments of a switching unit (also referred to as an "isolating circuit") using MOSFETs. n-channel MOSFETs are shown in each case. These are normally off and only conduct once they receive a control signal at the gate that exceeds their threshold voltage.However, an implementation with self-conducting p-channel MOSFETs would also be conceivable.

[0077] Fig. 15 shows a first embodiment of a switching unit in the form of a MOSFET 301. The body diode of a Si MOSFET only becomes conductive at an applied voltage of approximately 0.7 V. If the voltage drop across the MOSFET, which is caused by the current induced in the respective power coil, does not exceed 0.7 V, this would also be a possible implementation.

[0078] Since MOSFETs do not have to meet high dielectric strength requirements, the switching unit can be constructed with Si MOSFETs, for example with two anti-serially connected Si MOSFETs, as in the embodiment 302 shown in Fig. 16. In energy transfer mode, the MOSFETs should be permanently conductive, so that the only voltage drop across them is that caused by their on-resistance. This is generally in the single-digit mOhm range for high-current MOSFETs. The induced voltage in positioning mode is also relatively small (e.g., in the mV range). In energy transfer mode, the circuit is controlled such that, apart from the on-resistances of the two MOSFETs, it represents a short circuit and thus has no significant influence on energy transfer operation. In positioning mode, the MOSFETs are controlled such that they operate in blocking mode, thus preventing current flow through the GA.

[0079] To optimize heat generation, multiple parallel MOSFET paths can also be used, as shown in the embodiment 303 shown in Fig. 17. For example, the circuit is extended by a parallel path, which ensures that the current can be distributed across the paths and the individual MOSFETs heat up less.

[0080] This allows an even higher current carrying capacity to be achieved, which can be advantageous depending on the compensation topology.

[0081] If, for example, SiC MOSFETs are used instead of Si MOSFETs, as in the embodiment 304 shown in Fig. 18, dedicated diodes, for example Schottky diodes, should be used due to the high forward voltage of the body diodes (approx. 4.2V).

[0082] In addition to MOSFETs, other components are also conceivable as switching units, such as the triacs 305 shown in Fig. 19 or antiparallel-connected thyristors 306, which are controlled accordingly. A relay 307, shown in Fig. 20, is also conceivable as a switching unit.

[0083] Fig. 21 shows an embodiment of a circuit device 100 according to the invention with a parallel capacitance Cp and a series capacitance Cs, in which the switching unit 120 is realized by the embodiment 302 shown in Fig. 16. Fig. 22 shows an embodiment of a circuit device 100 according to the invention with a parallel capacitance Cp and a series capacitance Cs, in which the switching unit 120 is realized by two anti-serially connected MOSFETs.

[0084] In principle, there are various topologies for implementing reactive power compensation. As shown in Fig. 13, for example, a variable inductance jXGA, a parallel capacitor C2, and two series capacitors C1a and C1b can be used. C1a and C1b can also be combined into a single capacitor. A simplified circuit can also be constructed with only a single parallel or a single series capacitor. Furthermore, various combinations of serial and parallel capacitors and inductors are conceivable for implementing reactive power compensation.

[0085] Fig. 23 shows an embodiment of the circuit device 100 according to the invention, in which the compensation circuit unit 110 is formed without parallel capacitance C2, so that the resonant circuit is formed only from the series capacitance and the power coil. In this case, instead of the separate switching unit, the resonant circuit can be opened in positioning mode by appropriately controlling the inverter 152, in particular the four MOSFETs, and thus the current flow can be prevented. In Fig. 23, the inverter 152 is designed as a full bridge, but it can also consist of a half bridge. Here, too, the goal is to prevent the current flow in the resonant circuit of the respective power coil LGA and LVA by means of an open circuit.

[0086] Compensation circuit units with other capacitor arrangements are also conceivable. C1a and C1b can be combined into a single capacitor. The serial and / or parallel capacitors can also be omitted. If the parallel capacitor is omitted, the resonant circuit could also be opened in positioning mode by appropriately controlling the inverter, for example, by an optional converter control unit 160.

[0087] Fig. 24 shows an embodiment of the circuit device 200 according to the invention, in which the compensation circuit unit 210 is formed without parallel capacitance C2, so that the resonant circuit is formed only from the series capacitance and the power coil. The same variation options as described above with regard to the circuit device 100 can also be applied to the design of the compensation circuit unit 210 of the circuit device 100. For a pure series resonant circuit, as shown in Fig. 24, the resonant circuit can be opened by appropriately controlling the inverter 252 (in this case, an active rectifier), for example, by an optional converter control unit 260.

[0088] When implemented without parallel capacitance C2, the resonant circuit is formed solely by the series capacitance and the power coil. In this case, instead of a separate switching unit, the resonant circuit can be opened in positioning mode by appropriately controlling the rectifier, particularly the four MOSFETs, thus preventing current flow. Opening the circuit may not be successful with a passive rectifier (diodes instead of MOSFETs), so a switching unit / isolating circuit is still preferred.

[0089] Current carrying capacity is important for MOSFET design in this application, and a solution without dedicated diodes using Si MOSFETs is also conceivable. Since the MOSFETs are continuously conducting during power transfer, the voltage drop across the MOSFETs is determined solely by their on-state resistance. This is in the milliohm range and is therefore negligible compared to the voltage drop across the compensation parameter.

[0090] Fig. 25 shows an embodiment of a circuit device 100 according to the invention with control of the MOSFETs based on a control signal by a control unit 170. This control requires that the operating mode (energy transfer or positioning) is detected, for example on an external circuit board, or that the operating mode is known. This detection can be performed, for example, via a detection unit 180, e.g., a positioning GA controller board. This control signal can be used to enable the voltage supply for controlling the MOSFETs. During energy transfer operation, it must be ensured that the MOSFETs are permanently in the conductive state, which can be ensured, for example, by isolated control with sufficient gate voltage.

[0091] Fig. 26 shows an embodiment of a circuit device according to the invention with control of the MOSFETs based on a control signal from a control unit 170. In this embodiment, no external control signal is required to detect the operating mode. The voltage across the MOSFETs is measured by a voltage sensor 190, for example via a voltage sensor. If this voltage exceeds a defined threshold value (block 191), energy transfer mode is present, so that the switching unit 120 is closed ("ON"), whereby more current can flow. If this threshold value is undershot (block 192), positioning mode is present, so that the switching unit 120 is opened ("OFF"), whereby no more current can flow.

[0092] Fig. 27 shows an embodiment of a power coil 4 constructed from two parallel power coil windings 4a, 4b. This construction is particularly suitable for the power coil of the GA, but can also be used for the power coil of the VA. Fig. 28 shows an embodiment of a circuit device 100 according to the invention for such an embodiment of the power coil. A separate compensation circuit unit is provided for each power coil winding, each with two series capacitors C1a1, C1b1 and C1a2, C1b2, respectively, which are connected to a common parallel capacitor C2. The potential positions of switching units in this embodiment are marked by "X".

[0093] Fig. 29 shows a further embodiment of a circuit device 200 with a secondary-side series-compensated power coil LVA, which is connected to an active rectifier 251. In this case, by appropriately controlling the active rectifier 251, a switching unit, such as that shown in Fig. 14, can be dispensed with, since the circuit can be separated via the VA power coil by means of the active rectifier 251.

[0094] The present invention can also be advantageously used in embodiments of the inductive charging device without a compensation circuit unit for reactive power compensation. In particular, if the energy coil has two (or more) partial coils, especially partial coils connected in parallel, the problems described above can occur even without such a compensation circuit unit and lead to an undesired current flow. This current, in turn, builds up a magnetic field that influences the original field of the transmitting coils through superposition.

[0095] Fig. 30 shows an embodiment of an inductive stationary charging device 1b according to the invention without a compensation circuit unit for reactive power compensation. This charging device 1b comprises a voltage supply unit 150, a first energy coil (LGA) having at least two partial coils 4a, 4b, a positioning device 140 for detecting the relative positioning of the energy coils (i.e., the first energy coil LGA relative to the second energy coil LVA) to one another, and at least one switching unit. The switching unit can be arranged at different locations to separate the electrical connection between the voltage supply unit and the first energy coil or between the partial coils of the first energy coil. It can thus interrupt a current flow through the first energy coil.Reference numerals 122, 123, 124 designate switching units arranged at various locations, wherein one or more of these switching units may be provided. Fig. 31 shows an embodiment of a mobile inductive charging device 1a according to the invention without a compensation circuit unit for reactive power compensation. This charging device 1b comprises a voltage pickup unit 250, a second energy coil (LVA) having at least two partial coils 4c, 4d, a positioning device 141 for detecting the relative positioning of the energy coils to one another, and at least one switching unit. The switching unit can be arranged at different locations to disconnect the electrical connection between the voltage pickup unit and the second energy coil or between the partial coils of the second energy coil. It can thus interrupt a current flow through the second energy coil.The reference numerals 125, 126, 127 designate switching units arranged at different locations, wherein one or more of these switching units can be provided.

[0096] In summary, the present invention provides an effective, cost-effective, and easy-to-implement method for preventing current flow in the energy coil of the respective inductive charging device caused by unwanted coupling. According to the invention, neither current measurement nor corresponding control loops are required for this purpose.

Claims

Claims 1. A circuit device for reactive power compensation in an inductive charging device, the circuit device comprising: two input terminals for connecting a voltage supply unit or a voltage collector unit; two output terminals for connecting a first or second energy coil; a compensation circuit unit with a serial capacitance arranged between an input terminal and an output terminal and / or a parallel capacitance arranged between the two input terminals or the two output terminals; and at least one switching unit arranged in the compensation circuit unit for breaking the electrical connection between this input terminal and this output terminal and interrupting a current flow through an energy coil connected to the output terminals.

2. Circuit device according to claim 1, characterized in that the compensation circuit unit has a parallel capacitance arranged between the two input terminals or the two output terminals and one or two serial capacitances arranged between an input terminal and an output terminal, and / or the compensation circuit unit has one or two serial inductances arranged between an input terminal and an output terminal.

3. Circuit device according to one of the preceding claims, characterized in that the at least one switching unit is arranged between an input terminal and an output terminal, in particular arranged in series with the parallel capacitance and / or in series with the serial capacitance.

4. Circuit device according to one of the preceding claims, characterized in that the at least one switching unit comprises at least: a transistor, in particular at least one MOSFET, Si-MOSFET or SiC-MOSFET, a relay, a triac, or a thyristor.

5. Circuit device according to one of the preceding claims, characterized in that the at least one switching unit has two series-connected anti-serial MOSFETs, in particular Si or SiC MOSFETs, wherein in each case a diode is connected in parallel to the respective MOSFET, and / or that the at least one switching unit has a parallel connection of two MOSFET circuits, each of which has two series-connected anti-serial MOSFETs, in particular Si or SiC MOSFETs, wherein in each case a diode is connected in parallel to the respective MOSFET.

6. Circuit device according to one of the preceding claims, further comprising a control unit for controlling the at least one switching unit such that the at least one switching unit is closed when an energy coil connected to the output terminals is in an energy transmission mode in which it inductively transmits or receives energy, in particular that the at least one switching unit is only closed when an energy coil connected to the output terminals is in an energy transmission mode.

7. Circuit device according to claim 6, characterized in that the control unit is designed to receive and / or determine operating information which contains information as to whether the energy coil is in energy transmission mode, in particular that the control unit has a voltage sensor for determining the operating information by measuring a voltage across the at least one switching unit.

8. Circuit device according to one of claims 6 to 7, characterized in that the control unit has a voltage supply unit and a gate driver unit for driving a gate of at least one transistor.

9. An inductive charging device comprising: a circuit device according to any one of the preceding claims; a voltage supply unit or voltage pickup unit connected to the two input terminals of the circuit device; a first or second energy coil connected to the two output terminals of the circuit device; and a positioning device for detecting the relative positioning of the energy coils to one another.

10. Inductive charging device according to claim 9, characterized in that the inductive charging device is a stationary inductive charging device for mounting on and / or in a floor surface and the positioning device has at least one transmitting coil and / or a positioning signal coil for generating a positioning magnetic field, in particular in a positioning operation, or that the inductive charging device is a mobile inductive charging device for attachment to and / or in a vehicle and the positioning device has at least one receiving coil for detecting a positioning magnetic field, in particular in a positioning operation.

11. Inductive charging device according to one of claims 9 to 10, characterized in that the circuit device has a control unit for controlling the at least one switching unit such that the at least one switching unit is open when the positioning device is in a positioning mode in which the detection of the relative positioning of the energy coils to one another takes place, and the energy coils are not in an energy transmission mode in which they inductively transmit energy.

12. Inductive charging device according to one of claims 9 to 11, characterized in that the voltage supply unit or the voltage pickup unit each have a converter unit and a converter control unit, wherein the converter control unit is designed to interrupt a current flow through an energy coil connected to the output terminals, in particular when the positioning device is in a positioning mode in which the detection of the relative positioning of the energy coils to one another takes place, and energy coils are not in an energy transmission mode in which they inductively transmit energy.

13. Inductive charging device according to one of claims 9 to 12, characterized in that the first energy coil and / or the second energy coil has at least two partial coils and each partial coil is connected to the output terminals of a separate circuit device for reactive power compensation.

14. Inductive charging device with: i) a voltage supply unit and a first energy coil having at least two partial coils or ii) a voltage pickup unit and a second energy coil having at least two partial coils; a positioning device for detecting the relative positioning of the energy coils to one another; and at least one switching unit for breaking the electrical connection i) between the voltage supply unit and the first energy coil or ii) between the voltage pickup unit and the second energy coil or iii) between the partial coils of the first energy coil or the second energy coil and for interrupting a current flow through the first energy coil or the second energy coil.

15. A system for inductive energy transfer comprising an inductive charging device according to claim 13 and an inductive charging device according to claim 14.

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