Method and system for inductive transmission of electrical energy, as well as method for producing an inductive energy transmission system

Abstract

The invention relates to a method for the inductive transmission of electrical energy from a transmitter unit (10) to a receiver unit (20) of an inductive energy transmission system (100), comprising: - Generating a standing wave of a magnetic field used for inductive energy transmission by means of a multiphase transmitter winding of the transmitter unit (10), wherein the standing wave is adapted to a relative position of the transmitter winding and a receiver winding of the receiver unit (20). Furthermore, the invention relates to a transmitter system for inductive transmission of electrical energy, an inductive energy transmission system (100; 200), and a method for producing an inductive energy transmission system (100; 200).

Description

[0001] The invention relates to a method for the inductive transmission of electrical energy. Furthermore, the invention relates to an inductive energy transmission system and a method for producing an inductive energy transmission system.

[0002] Inductive energy transfer systems or charging systems are fundamentally based on a magnetic flux coupling of transmission coils in a transmitter and receiver unit of the energy transfer system. This therefore requires a minimum level of accuracy in the positioning of the transmission coils. For example, in the automotive sector, for light electric commercial vehicles ("Light-Duty EVs") with a charging power greater than 3.3 kW, a positioning tolerance of +75 mm in the direction of travel and +100 mm transverse to the direction of travel is permissible according to current standardization (SAE J2954). In order to maintain this positioning tolerance, for example when parking an electric vehicle in the charging area of an inductive charging station, various approaches for assistance systems or for additional sensors to support the alignment of the transmission coils are currently being discussed by various companies and institutions.In addition, maximum permissible operating limits must be observed during electrical charging. For example, certain magnetic limits must not be exceeded during inductive charging. To ensure this, the transmission power can be reduced in charging systems with low charging power (in the range of < 100 W), a process known as "power derating." However, for charging powers > 100 W, a reduction in power and / or efficiency is generally not accepted or tolerated for cost and efficiency reasons.

[0003] Due to the current level of maturity in research and development, single-phase inductive charging systems are primarily used to date. Single-phase charging systems utilize a stationary magnetic field for energy transfer. Due to the stationary nature of the magnetic field, the transmission efficiency of single-phase inductive charging systems is highly dependent on the relative positioning of the transmission coils. Therefore, single-phase inductive charging systems generally require assistance systems to ensure the most precise positioning of the transmission coils. However, assistance systems for positioning the coils do not contribute to the energy transfer itself and increase costs and system vulnerability.

[0004] Multiphase inductive transmission concepts are still in their early stages of development and are currently based on traveling waves. While the positioning tolerance of three-phase inductive transmission based on traveling waves is higher than that of single-phase inductive transmission, traveling waves have the significant disadvantage that high local losses can occur in certain areas on the receiver side of the power transmission system and / or magnetic limits can be exceeded.

[0005] It is therefore an object of the present invention to provide an improved contactless or inductive transmission of electrical energy, in particular for electric vehicles. In particular, it is an object of the invention to enable a largely constant coupling factor between the transmission windings of the transmitter and receiver units of an inductive energy transmission system for practical or realistic positioning accuracy of the receiver unit. Especially in electric vehicles (but also other mobile applications), it is desirable that the coupling factor, at least within a certain positioning range, has the lowest possible sensitivity to a change in the relative position of the transmission windings of an inductive energy transmission system. Furthermore, it is desirable to be able to dispense with additional assistive sensors for positioning the receiver unit, which are expensive and error-prone.

[0006] The above-mentioned object is achieved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0007] A first independent aspect for solving the problem relates to a method for inductively transmitting electrical energy from a transmitter unit to a receiver unit of an inductive energy transmission system, comprising: - generating a standing wave, in particular a moving and / or field-orientable or field-oriented, of a magnetic field used for inductive energy transmission by means of a multi-phase transmitter winding of the transmitter unit, wherein the standing wave is adapted (or tuned) to a relative position of the transmitter winding and a receiver winding of the receiver unit.

[0008] The transmitter unit (transmitter) is arranged on a transmitter side or primary side of the energy transmission system and essentially comprises a transmitter winding or transmitter coil. The transmitter winding or transmitter coil is also referred to as the primary winding or primary coil in this description. It is understood that the transmitter side or receiver side can also comprise further elements, such as a power inverter, a compensation circuit or compensation network, and / or signal electronics.

[0009] The standing wave of a magnetic field used for inductive energy transfer (or of a magnetic field component used for energy transfer) is in particular a moving and / or field-oriented standing wave. In the context of this description, a “moving” standing wave is understood to mean that the standing wave can be moved or shifted, in particular in a lateral direction (i.e. perpendicular to the direction of the magnetic field used for inductive energy transfer). The moving standing wave differs fundamentally from a traveling wave. While the traveling wave naturally shifts over time, the moving standing wave cannot change parameters without an explicit change in parameters (in particular electrical currents flowing through a winding orCoil, through which the moving standing wave is generated, is applied) remains spatially constant over time (so that fixed locations of maximum and minimum flux density of the magnetic field are formed). A traveling wave is, by definition, not a standing wave. In the context of this description, a field-oriented standing wave is understood to mean that the standing wave is oriented or aligned with a position of the receiver unit or the receiver winding. In particular, adjusting the generated standing wave results in a field-oriented standing wave.

[0010] For the purposes of this description, the term "multi-phase transmitter or receiver winding" particularly encompasses a multi-phase winding arrangement and / or a multi-phase winding system. The term "multi-phase transmitter or receiver winding" therefore refers, in particular, to multiple windings that are arranged in a specific manner relative to one another and / or form an associated system with multiple phases or strands. The terms "phase" and "strand" are used synonymously when referring to a winding (or a winding arrangement and / or a winding system). For example, the multi-phase transmitter or receiver winding is a three-phase transmitter or receiver winding.

[0011] The method may, in particular, comprise providing an inductive energy transmission system for transmitting electrical energy from a transmitter unit (primary side) to a receiver unit (secondary side) of the energy transmission system. Furthermore, the method may also comprise the following step: - Adapting or optimizing, in particular aligning and / or shifting, the standing wave with respect to a position of the receiver unit (or receiver winding) and / or with respect to a relative position of the transmitter unit (or transmitter winding) and receiver unit (or receiver winding) of the energy transmission system.

[0012] The present invention enables a drastic increase in lateral positioning tolerance, for example, in the inductive charging of electric vehicles, so that an assistance system for fine positioning of the transmission windings or coils can advantageously be dispensed with. Thus, the invention enables, in particular, a largely constant coupling factor between the transmission windings of the transmitter and receiver units of an inductive energy transmission system for practical and realistic positioning accuracy of the receiver unit.

[0013] In particular, by generating and adapting a (movable and / or field-orientable) standing wave of the magnetic field used for energy transmission, it can advantageously be achieved that the coupling factor, at least in a certain positioning range, has a comparatively low sensitivity to a change in the relative position of the transmission windings.

[0014] In a preferred embodiment, to generate the standing wave, each of a plurality of phases of the multiphase transmitter winding is impressed with a respective phase current, wherein all phase currents have the same electrical phase. In other words, all phase currents flowing through the multiphase transmitter winding are in phase. In particular, all voltages or phase voltages applied to the respective phases of the multiphase transmitter winding (to generate the corresponding phase currents) are also in phase. In an N-phase transmitter winding, N in-phase phase currents are applied to the N phases or phases. Here, N denotes an integer greater than 1. In particular, the transmitter winding is three-phase, and thus N = 3.

[0015] For the current i n(t), which is or will be impressed on the n-th phase of the multi-phase transmitter winding, applies in particular: in(t)=i^n sin(ωt) ∀n ∈ NPhase

[0016] This refers to NPhase the number of existing phases or strands. The total number N of existing strands is: N=max NPhase. Furthermore, î n an amplitude of the n-th phase current i n (t), ω is a frequency or angular frequency, and t is time. For example, in the case of a three-phase winding with N = 3, the following applies to a first phase a, a second phase b, and a third phase c: ia(t)=i^a sin(ωt) ib(t)=i^b sin(ωt) ic(t)=i^c sin(ωt)

[0017] Here, î a an amplitude of the phase current i a (t), î b an amplitude of the phase current i b (t), î c an amplitude of the phase current i c(t), ω is a frequency or angular frequency and t is time.

[0018] In a further preferred embodiment, the standing wave is adjusted (and / or optimized) by adjusting or setting the amplitudes of in-phase phase currents applied to (the associated phases or phases) of the multiphase transmitter winding. In other words, adjusting (and / or optimizing) the standing wave comprises adjusting the amplitudes of in-phase phase currents applied to (the associated phases or phases) of the multiphase transmitter winding.

[0019] In a further preferred embodiment, the amplitudes of the in-phase phase currents are adapted (or set) in such a way that a coupling (or a coupling factor) between the transmitter unit (or the transmitter winding) and the receiver unit (or the receiver winding) is maximum. In other words, adapting the standing wave comprises determining (in particular measuring) a coupling or a coupling maximum between the transmitter unit (or transmitter winding) and the receiver unit (or receiver winding). Determining a coupling between the transmitter unit (or transmitter winding) and the receiver unit (or receiver winding) can be done e.g. via the impedance and / or power behavior of the transmitter unit or transmitter winding. Preferably, the setting of the phase currents or the adaptation of the phase current amplitudes is done by scanning orSearch process in which a system response, for example the power fed in from the primary side, is evaluated step by step for different orientations of the moving standing wave. In particular, the adjustment of the phase current amplitudes comprises a (step by step or continuous) change or "sweeping" of the phase current amplitudes and / or a detection (in particular measuring) of a system response of the inductive energy transfer system (or the transmitter and / or receiver unit of the inductive energy transfer system). Alternatively or additionally, the adjustment of the phase current amplitudes particularly comprises an evaluation of the system response. The system response can comprise, for example, an impedance and / or a power (or an impedance and / or power behavior). If the system response is determined on the transmitter side or by means of the transmitter unit, communication with the receiver unit or receiver winding is not required.Determining a coupling between the transmitter unit and the receiver unit can thus be done exclusively on the transmitter side or exclusively by means of the transmitter unit (i.e., independently of the receiver side or the receiver unit). In particular, no explicit knowledge of the relative position of the transmitter and receiver units is required for this purpose.

[0020] In a further preferred embodiment, the method comprises providing the inductive energy transmission system, wherein a dimension or a total length of the multi-phase transmitter winding of the energy transmission system substantially corresponds to a period length of the standing magnetic field wave generated for energy transmission. In other words, a total length of the multi-phase transmitter winding of the energy transmission system is or will be matched to a period length of the standing magnetic field wave generated for energy transmission. In other words, a total length of the multi-phase transmitter winding of the energy transmission system is or will be dimensioned based on a period length of the standing magnetic field wave generated for energy transmission. Alternatively or additionally, a dimension orThe total length of the receiver winding of the energy transmission system essentially corresponds to the period length of a fundamental or harmonic wave of the magnetic field used for energy transmission. In other words, the total length of the receiver winding of the energy transmission system is or will be matched to the period length of a fundamental or harmonic wave of the magnetic field used for energy transmission. In other words, the total length of the receiver winding of the energy transmission system is or will be dimensioned based on the period length of a fundamental or harmonic wave of the magnetic field used for energy transmission.

[0021] In particular, it has been found within the scope of the present invention that with clever geometric dimensioning (tuning) of the transmission windings based on the period length of a fundamental or harmonic wave of the magnetic field used for energy transmission, the magnetic flux coupling between the transmitter and receiver sides can be increased or maximized. In particular, it has been found that not only the period length λ of the fundamental wave of the magnetic field used for energy transmission is suitable for tuning, but also the period length of a corresponding harmonic wave (such as the period length λ2 = λ / 2 of the second harmonic, the period length λ3 = λ / 3 of the third harmonic, the period length λ4 = λ / 4 of the fourth harmonic, etc., of the magnetic field used for energy transmission).For example, the total length of the transmitter and / or receiver winding can essentially correspond to the period length λ of the fundamental wave of the magnetic field used for energy transmission. Alternatively, the total length of the receiver winding can essentially correspond to the period length λ2 = λ / 2 of the second harmonic, the period length λ3 = λ / 3 of the third harmonic, the period length λ4 = λ / 4 of the fourth harmonic, etc., of the magnetic field used for energy transmission. Within the scope of the present invention, it has been found that with such dimensioning of the transmitter unit or the transmitter winding, the magnetic flux coupling between the transmitter and receiver sides can be increased or maximized.

[0022] In the context of this description, the term "substantially" with respect to a specified dimension (e.g., size or length) means, in particular, that an actual dimension (e.g., size or length) may deviate from the specified dimension (size or length) within the scope of usual manufacturing tolerances. For example, "substantially" may mean that an actual dimension (e.g., size or length) deviates from the specified dimension (size or length) by less than 10%, preferably by less than 5%, and particularly preferably by less than 3%.

[0023] In a further preferred embodiment, the method comprises providing the inductive energy transmission system, wherein the receiver winding has one or more (in particular meander-shaped or lined up) turns, each with a turn diameter that essentially corresponds to half the period of a fundamental or harmonic wave of the magnetic field used for energy transmission. For example, the turn diameter can essentially correspond to half the period λ / 2 of the fundamental wave of the magnetic field used for energy transmission. Alternatively, the turn diameter can essentially correspond to half the period λ2 / 2 = λ / 4 of the second harmonic, half the period λ3 / 2 = λ / 6 of the third harmonic, half the period λ4 / 4 = λ / 8 of the fourth harmonic, etc., of the magnetic field used for energy transmission.Within the scope of the present invention, it has been found that with such dimensioning of the receiver unit or the receiver winding, the magnetic flux coupling between the transmitter and receiver sides can be increased or maximized.

[0024] In the context of the present description, a “winding diameter” is understood to mean in particular an average value of an inner and outer winding diameter. A winding can be a circular or spiral winding (i.e. a winding with a circular cross-section), or also, for example, a rectangular winding (i.e. a winding with a rectangular cross-section). In this context, the “winding diameter” of a circular winding is understood to mean in particular the diameter of a circle spanned by the winding (in a plan view). In the context of this description, the “winding diameter” of a rectangular winding is understood to mean in particular a (smallest and / or largest) distance between (approximately) opposite sides of a rectangle spanned by the winding (in a plan view).a (smallest and / or largest) distance between (approximately) opposite (essentially parallel) conductors or conductor sections of the winding. In the context of this description, the "winding diameter" does not refer to a wire diameter.

[0025] In a further preferred embodiment, the method comprises providing the inductive energy transmission system, wherein the transmitter winding is a three-phase winding, and wherein the receiver winding is a single-phase winding, in particular a single-phase DDD winding. The receiver winding is preferably meander-shaped. In particular, the receiver winding comprises at least one, in particular several and preferably more than three windings arranged in a meandering or D-shape. In other words, the receiver winding preferably has a D-shaped winding configuration or winding arrangement. For example, the receiver winding can comprise or be a so-called D-winding or a DD-winding. The receiver winding preferably comprises or is a DDD or DDDD winding. In particular in interaction with the multiple orthree-phase primary side, it has been found in the context of the present invention that in this way the generated magnetic field can be used to a much greater extent for energy transmission than with conventional circular windings or DD windings.

[0026] Another independent aspect to solve the problem concerns an inductive energy transfer system comprising: - a transmitter unit with a multi-phase transmitter winding designed to generate a standing wave of a magnetic field used for inductive energy transmission; - a receiver unit with a single-phase or multi-phase receiver winding; and - an adaptation unit which is designed to adapt the standing wave to a relative position of the transmitter winding and the receiver winding.

[0027] In particular, the contactless or inductive energy transmission system is a system for transmitting electrical energy from the transmitter or primary side to the receiver or secondary side. In other words, the energy transmission system is a system for converting electrical energy (on the transmitter side) into electrical energy (on the receiver side). The receiver unit is in particular designed to generate an induced voltage and / or an induced current based on the magnetic field generated by the transmitter unit. In particular, the matching unit comprises one or more current sources for applying (in-phase) phase currents to the phases or phases of the multi-phase transmitter winding. In particular, the matching unit comprises a measuring unit for determining a coupling between the transmitter unit and the receiver unit. In particular, the matching unit comprises a processor orA microprocessor for controlling the current source(s), wherein the processor or microprocessor is configured to adapt or adjust the amplitudes of the phase currents impressed on the multiphase transmitter winding such that the coupling or a coupling factor between the transmitter unit (or the transmitter winding) and the receiver unit (or the receiver winding) is maximized. For example, such adaptation can be achieved via an impedance and / or power measurement of the transmitter unit or transmitter winding. Accordingly, the adaptation unit can comprise an impedance measuring device and / or a power measuring device, which is controlled in particular by the processor.

[0028] A further independent aspect for solving the problem relates to a transmitter system for an inductive transmission of electrical energy (in particular for use in an inductive energy transmission system), comprising: - a transmitter unit with a multi-phase transmitter winding designed to generate a standing wave of a magnetic field used for inductive energy transmission; and - an adaptation unit which is designed to adapt the standing wave to a position of the transmitter winding relative to a receiver winding (of the inductive energy transmission system).

[0029] In particular, the statements made regarding the transmitter unit and adaptation unit with regard to the first aspect also apply to the aforementioned further aspect. As already mentioned above, communication with the receiver unit or receiver winding is not required to adapt the standing wave to a relative position of the transmitter winding and receiver winding. Determining a coupling between the transmitter unit and the receiver unit can only be done on the transmitter or primary side (i.e., independently of the receiver unit of the energy transmission system). This is possible, for example, (solely) via the impedance and / or power behavior of the transmitter unit or transmitter winding.

[0030] Explicit knowledge of the relative position of the transmitter and receiver units is not required.

[0031] A further independent aspect for solving the problem relates to a method for producing (or providing) an inductive energy transmission system, comprising the steps: - Providing a transmitter unit for generating a magnetic field used for energy transmission; and - Providing a receiver unit for generating an induced voltage and / or an induced current based on the magnetic field generated by the transmitter unit;wherein a total length and / or at least one winding diameter of a receiver winding of the receiver unit is / will be matched to a period length of a fundamental or harmonic wave of the magnetic field generated by the transmitter unit.

[0032] According to this aspect, the transmitter unit can be single-phase or multi-phase. For example, the transmitter unit is a single-phase transmitter unit with a transmitter winding comprising transmitter windings arranged in a meandering pattern or lined up in a row. Each winding diameter of these transmitter windings preferably corresponds substantially to half the period length of a magnetic field wave used for energy transmission. Alternatively, the transmitter unit can comprise a multi-phase transmitter winding. In this case, a total length of the multi-phase transmitter winding preferably corresponds substantially to a period length of a magnetic field wave used for energy transmission. The total length of the receiver winding refers in particular to a total length along a longitudinal axis of the receiver winding or the receiver unit.In an operating state of the energy transmission system, this longitudinal axis of the receiver winding is preferably oriented substantially perpendicular to a (predetermined) direction of the magnetic field generated by the transmitter unit. In particular, the period length of a wave (fundamental or harmonic) of the magnetic field used for energy transmission is predetermined or fixed by the provided transmitter unit.

[0033] In a preferred embodiment, the total length of the receiver winding is matched to the magnetic field generated by the transmitter unit in such a way that the total length of the receiver winding substantially corresponds to the period length of a fundamental or harmonic of the magnetic field generated by the transmitter unit. Alternatively or additionally, the at least one winding diameter of the receiver winding is matched to the magnetic field generated by the transmitter unit in such a way that the at least one winding diameter of the receiver winding substantially corresponds to half the period length of a fundamental or harmonic of the magnetic field generated by the transmitter unit. For example, the winding diameter can substantially correspond to half the period length λ / 2 of the fundamental wave of the magnetic field used for energy transmission.Alternatively, the winding diameter can essentially correspond to half the period length λ2 / 2 = λ / 4 of the second harmonic, half the period length λ3 / 2 = λ / 6 of the third harmonic, half the period length λ4 / 4 = λ / 8 of the fourth harmonic, etc., of the magnetic field used for energy transmission. Within the scope of the present invention, it has been found that with such dimensioning of the receiver unit or the receiver winding, the magnetic flux coupling between the transmitter and receiver sides can be increased or maximized.

[0034] Another independent aspect to solve the problem concerns an inductive energy transmission system, comprising: - a transmitter unit for generating a magnetic field used for energy transmission; and - a receiver unit with a receiver winding; where: a total length of the receiver winding essentially corresponds to a period length of a fundamental or harmonic wave of the magnetic field generated by the transmitter unit, and / or at least one winding diameter of the receiver winding corresponds substantially to half a period length of a fundamental or harmonic wave of the magnetic field generated by the transmitter unit.

[0035] In a preferred embodiment, the transmitter unit comprises a transmitter winding with one or more windings (in particular arranged in a meandering pattern or lined up in a row), wherein a winding diameter of each of the one or more windings essentially corresponds to half the period length of a magnetic field wave used for energy transmission. Preferably, in this embodiment, the receiver unit or the receiver winding is multi-phase (in particular three-phase). Preferably, in this embodiment, the total length of the receiver winding essentially corresponds to the period length of the magnetic field wave used for energy transmission or to a period length of a harmonic of the magnetic field generated by the transmitter unit.

[0036] In particular, a dimension or a total length of the transmitter winding is matched to a period length of a magnetic field wave used for energy transmission. In other words, the transmitter winding (in particular a total length of the transmitter winding) is dimensioned based on a (specified) period length of a magnetic field wave used for energy transmission. Alternatively or additionally, a dimension or a total length of the receiver winding is matched to a period length of a fundamental or harmonic of the magnetic field generated by the transmitter unit. In other words, the receiver winding (in particular a total length of the receiver winding) is dimensioned based on a (specified) period length of a fundamental or harmonic of the magnetic field generated by the transmitter unit.

[0037] In particular, the transmitter unit comprises a transmitter winding with one or more turns, wherein the one or more turns of the transmitter winding each have a turn diameter that essentially corresponds to half a period length of a magnetic field wave used for energy transmission.

[0038] In particular, the method according to the invention for the inductive transmission of electrical energy, the transmitter system according to the invention, and / or the inductive energy transmission system according to the invention can be used for charging an electric vehicle. Thus, according to a further aspect, the invention provides an inductive charging system for electric vehicles, which comprises an inductive energy transmission system according to the invention.

[0039] It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also individually or in other combinations without departing from the scope of the present invention. The above-mentioned or below statements regarding the embodiments of the first aspect also apply to the above-mentioned further independent aspects and in particular to related preferred embodiments. In particular, the above-mentioned and below statements regarding the embodiments of the other independent aspects also apply to an independent aspect of the present invention and to related preferred embodiments.

[0040] In the following, individual embodiments for achieving the object are described by way of example with reference to the figures. In some cases, the individual embodiments described have features that are not absolutely necessary to carry out the claimed subject matter, but which provide desired properties in certain applications. Thus, embodiments that do not have all the features of the embodiments described below are to be regarded as falling within the scope of the described technical teaching. Furthermore, to avoid unnecessary repetition, certain features are only mentioned in relation to individual embodiments described below. It is pointed out that the individual embodiments should therefore not only be considered in isolation, but also in conjunction with one another.Based on this overview, those skilled in the art will recognize that individual embodiments may also be modified by incorporating one or more features of other embodiments. It is noted that a systematic combination of the individual embodiments with one or more features described with reference to other embodiments may be desirable and useful and should therefore be considered and considered to be encompassed by the description. Short description of the drawings Fig. 1a shows a schematic drawing of the principle of single-phase inductive energy transfer in the near field; Fig. 1b shows a schematic drawing of the principle of multiphase inductive energy transfer in the near field; Fig. Figure 2a shows a schematic drawing of a single-phase circular winding; Fig. Figure 2b shows a schematic drawing of a single-phase DD winding; Fig. Figure 2c shows a schematic drawing of a three-phase distributed winding; Fig. Figure 2d shows a schematic drawing of a three-phase concentrated winding; Fig. Figure 3 shows a schematic drawing of a stationary temporally oscillating magnetic field generated by a single-phase primary side; Fig. Figure 4 shows a schematic drawing of a traveling magnetic field wave generated by a three-phase primary; Fig. Figure 5a shows a schematic drawing illustrating the reduction of the coupling factor due to a displacement or mispositioning of the secondary side 20 in a single-phase inductive power transmission system; Fig. 5b shows a schematic drawing illustrating a measure for reducing the coupling change due to a displacement or mispositioning of the secondary side 20 at the expense of the absolute coupling factor; Fig. Figure 6 shows a schematic drawing of a traveling wave in multiphase inductive power transmission systems; Fig. Figure 7a shows a schematic drawing of the principle of the moving standing wave according to a preferred embodiment of the invention with a space vector placed at the position θ = λ / 2; Fig. 7b shows a schematic drawing of the principle of the moving standing wave according to a preferred embodiment of the invention with a space vector placed at the position θ = 3λ / 4; Fig. Figure 8a shows a schematic drawing of a single-phase DDD winding in a perspective view, shown in the xy plane; Fig. 8b shows a schematic drawing of an inductive energy transfer system 100 with a three-phase primary side 10 and a single-phase secondary side 20 according to a preferred embodiment of the present invention, wherein the primary side 10 and the secondary side 20 are centered relative to each other; Fig. Figure 8c shows a schematic drawing of the inductive energy transfer system 100 of Fig. 8b, wherein the primary side 10 and the secondary side 20 are shifted relative to each other; Fig. Figure 9a shows a schematic drawing of a single-phase DDDD winding in a perspective view, shown in the xy plane; Fig. 9b shows a schematic drawing of an inductive energy transmission system 100 with a three-phase primary side 10 and a single-phase secondary side 20 according to another preferred embodiment of the present invention, wherein the primary side 10 and the secondary side 20 are aligned centered relative to each other; Fig. 9c shows a schematic drawing of the inductive energy transfer system 100 of Fig. 8b, wherein the primary side 10 and the secondary side 20 are shifted relative to each other; Fig. 10a shows a schematic drawing of a single-phase primary side in DDD winding form and a three-phase secondary side of a power transmission system according to an embodiment of the present invention; Fig. 10b shows a schematic drawing of a single-phase primary side in DDDD winding form and a three-phase secondary side of a power transmission system according to an embodiment of the present invention; Fig. 11a shows a schematic drawing of a planar arrangement of geometrically distributed windings and associated exemplary fundamental wave space vectors per phase flux density for a symmetrical three-phase winding; Fig. Figure 11b shows a schematic drawing of a planar arrangement of geometrically distributed windings and associated exemplary fundamental wave space vectors per phase flux density for a general multiphase winding; Fig. Figure 11c shows a schematic drawing of the space vector addition of geometrically distributed strand flux densities for a symmetric three-phase system; Fig. Figure 11d shows a schematic drawing for the space vector addition of geometrically distributed strand flux densities for a general multiphase system; Fig. Figure 12a shows the principle of an inverse space vector composition for determining the amplitudes of the phase currents of a multiphase winding; Fig. 12b shows a phasor diagram to explain a “dq transformation”; Fig. Figure 13a shows a schematic drawing of a simplified exemplary primary air gap magnetic field with pronounced harmonics; Fig. 13b shows a schematic drawing for the design of the secondary side using the fundamental wave according to an embodiment of the invention; Fig. 13c shows a schematic drawing for the design of the secondary side using the third harmonic according to an embodiment of the invention. Detailed description of the drawings

[0041] The Fig. Figure 1a shows a schematic diagram of the basic principle of single-phase inductive energy transfer in the near field. Electrical energy is transferred contactlessly from a transmitter unit 10 (primary side) to a receiver unit 20 (secondary side) using a magnetic field. Both the transmitter unit 10 and the receiver unit 20 each comprise a single phase or a single phase. As a result of a voltage U1 applied to the phase of the transmitter unit 10, a current I1 flows through a transmitter winding on the primary side. This current I1 generates a magnetic flux ϕ, which penetrates a receiver winding on the secondary side. This creates an induced voltage U2 on the phase of the receiver unit 20.

[0042] The Fig. Figure 1b shows a schematic diagram of the basic principle of multi-phase inductive energy transmission in the near field. In contrast to single-phase inductive energy transmission, the transmitter unit 10 comprises not just one, but several phases or strands. Fig. 1b, phases a and b are explicitly shown. Any additional phases are indicated by the three dots. A voltage is applied to each of the existing phases, thus generating a corresponding phase current. Thus, at phase a, a voltage U 1a which carries a current I 1a generated, while at string b the voltage U 1b which carries a current I 1b All phases of the primary side contribute to the generation of a magnetic flux ϕ, which penetrates the receiver winding of the secondary side, so that an induced voltage U2 is generated at the phase of the receiver unit 20.

[0043] The inductive coupling between the transmitter unit 10 and the receiver unit 20 through the magnetic flux ϕ depends on the relative positioning of the transmitter unit 10 and the receiver unit 20. This position-dependent sensitivity of the magnetic coupling is particularly pronounced in single-phase inductive power transmission, as is mostly conventionally used. Therefore, for sufficiently precise positioning of the primary side 10 and the secondary side 20, additional assistance systems are generally necessary, especially in conventional single-phase power transmission systems. The two operating concepts, single-phase and three-phase, are presented in more detail below. The three-phase system is an example of all multi-phase systems that use a rotating field or traveling field for power transmission.

[0044] The Fig. 2a and Fig. 2b show schematically simplified exemplary single-phase winding types in cross-section. Fig. 2a a single-phase circular winding and in Fig. 2b shows a single-phase DD winding, each with a single phase a. For the current i a (t) of the phase a of the single-phase winding is as follows: ia(t)=i^ sin(ωt) where î is a constant amplitude, where ω is a frequency or angular frequency, and where t is the time.

[0045] The Fig. 2c and Fig. 2d show schematically simplified exemplary three-phase winding types in cross-section. Fig. 2c a three-phase distributed winding and in Fig. 2d shows a three-phase concentrated winding, each with phases a, b, and c. For the current i a (t) of strand a, the current i b (t) of the strand b, and the current i c (t) of the phase c of the three-phase winding, the following applies: ia(t)=i^ sin(ωt+0) ib(t)=i^ sin(ωt+2π3) ic(t)=l^ sin(ωt−2π3) where î denotes an amplitude which is constant for all phase currents i a (t), i b (t) and i c (t), where ω is a frequency or angular frequency, and where t is time.

[0046] Although the resulting B-fields of the winding types shown exhibit local differences, the following two winding types, "circular - single-phase" and "distributed - three-phase," are used to illustrate the basic principles. With regard to field harmonics, the principles shown apply analogously to the other single-phase and three-phase winding arrangements.

[0047] The Fig. Figure 3 shows a schematic drawing of a stationary, temporally oscillating magnetic field (B-field) generated by a single-phase primary side or transmitter unit 10. The magnetic field is directed in the z-direction, ie, orthogonal to an xy-plane in which the transmitter unit 10 is located. Fig. 3 is therefore the magnetic flux density B z in the z-direction. The Fig. 3 represented coordinate θ mech (t) denotes a position or location. The magnetic field of single-phase systems is fixed in space and oscillates in time with an excitation frequency ω in its amplitude (which is Fig. 3 is indicated by the dashed wave and the vertical double arrow. The position θ(t) of a space vector R is constant or stationary and oscillates in magnitude. The position of the B field is thus determined by the spatial placement of conductor windings (strand +a or -a) of the transmitter unit 10.

[0048] The Fig. Figure 4 shows a schematic diagram of the principle of the so-called traveling wave, which is conventionally used in multiphase inductive energy transmission. To illustrate the principle of the traveling wave, the B-field of the Fig. 4, the transmitter unit 10 is examined for its field harmonics over time. The fundamental wave is shown as an example for the two times t1 and t2. The period length λ corresponds to the geometric length of the winding arrangement or transmitter unit 10. The z-component B is used to transfer energy to an opposite coil. z The term traveling wave arises from the observation that the sinusoidal shape of the fundamental wave changes locally along θ mech (t), where θ mecha position or location. A traveling wave, as shown in the figure, is based on a symmetrical three-phase system with 120° electrical phase shift and a spatially shifted arrangement of the phases by ±λ / 3 of the period length λ. Fig. 4 is the magnetic flux density B z The fundamental wave (first harmonic) of the generated B field in the z-direction is shown schematically over a period λ. The space vector R is oriented at the maximum of both curves at times t1 and t2. This moves from a first position θ(t1) to a second position θ(t2) with ωtλ. Thus, traveling waves result from alternating currents with symmetrically shifted electrical and geometric phases at constant amplitude. In three-phase systems, this phase shift is +120°, as can also be seen from equations (6) to (8) above.

[0049] The Fig. Figure 5a shows, in the left and right sub-images, a schematic drawing of a primary side 10 and a secondary side 20 of a single-phase inductive energy transmission system. In the left sub-image, the primary side 10 and the secondary side 20 are centered relative to each other, while in the right sub-image, the secondary side 20 is offset relative to the primary side 10. The hatched area shown in the left and right sub-images represents the magnetic flux change in the secondary winding of the secondary side 20. As can be seen from a comparison of the left and right sub-images of the Fig. As can be seen in Figure 5a, the inductive coupling is reduced by a displacement of the secondary side 20 relative to the primary side 10 (as shown in the right-hand part of the figure). In other words, a displacement or mispositioning of the transmission windings leads to a reduction of the coupling factor. As already explained in connection with Fig. As mentioned in section 3, single-phase inductive charging systems are limited to a locally fixed B field (the intensity of which can only be varied). This context gives rise to the requirement for the accuracy of the alignment of primary side 10 and secondary side 20.

[0050] The Fig. 5b shows similar to the Fig. 5a in the left and right part of the figure a schematic drawing of a primary side 10 and a secondary side 20 of a single-phase inductive energy transmission system. The difference to Fig. 5a is that the receiver unit or secondary side 20 has been reduced in size. This represents a measure to reduce the coupling change due to a displacement or mispositioning of the secondary side 20 at the expense of the absolute coupling factor. In general, the positioning tolerance can be increased by a different dimensioning of one of the two loading units (i.e. primary side 10 or secondary side 20). One of the two units or sides is designed to be larger in area than the other, as in the example of the Fig. 5b is shown.

[0051] In the Fig. 5a and Fig. Figure 5b shows the area balance of the right-hand partial images (which each show a secondary side 20 shifted relative to the primary side 10) compared to the left-hand partial images (which each show a secondary side 20 aligned centrally relative to the primary side 10) an improvement of k zentriert ≈ 3kverschoben in Fig. 5a to k zentriert ≈ 2k veschoben in Fig. 5b. Although the positioning tolerance of these systems can be increased by dimensioning one of the two transmission units differently in terms of area at the expense of absolute flux coupling, these single-phase inductive energy transfer systems are nevertheless subject to a pronounced sensitivity of the coupling factor to the relative alignment of the primary side 10 and secondary side 20 (especially the primary winding and secondary winding). A crucial disadvantage of single-phase inductive charging systems is therefore the stationary B field, which requires a positioning assistance system to maintain a permissible coupling factor (as described above). However, assistance systems for positioning the coils do not contribute to the energy transfer of the charging system and thus increase costs and system vulnerability.

[0052] The Fig. Figure 6 shows a schematic drawing of a traveling wave in multi-phase inductive power transmission systems. Such multi-phase systems with traveling wave operation are more advantageous with regard to the positioning tolerance of the secondary side 20 due to the moving B-field. The traveling wave continuously traverses the entire air gap above the primary side 10. Particularly with a shifted or misaligned secondary side 20, this can lead to the flux change being maximized in an edge region and increased losses occurring, e.g., in a vehicle underbody 2. Furthermore, this can lead to limit values regarding the permissible flux density being exceeded in an edge or sill area 4 (e.g., of an electric vehicle). The entire area surrounding the primary side 10 experiences the full amplitude of the flux change due to the traveling wave, which can lead to the aforementioned problems. Fig. 6 describes such a scenario for a secondary side 20 that is unaligned relative to the primary side 10.

[0053] Within the scope of the invention, it has been found that a largely constant coupling factor between the windings or coils of the primary and secondary sides for a realistic positioning accuracy of the secondary side can be realized, in particular, by a multi-phase design of the transmitter unit or primary side 10, wherein a (movable) standing wave is generated by the transmitter unit 10 and arranged such that the magnetic flux through the receiver unit 20 is essentially constant for a wide positioning range of the receiver unit 20. This field-oriented approach allows a locally variable shaping of the magnetic field used for energy transmission by aligning the space vector of the field harmonics to be used to the receiver position and modulating its amplitude. The principle of the moving standing wave is described in the Fig. 7a and Fig. 7b.

[0054] The Fig. 7a and Fig. 7b show schematic drawings of the principle of a moving standing wave according to a preferred embodiment of the present invention. Based on the position of the space vector R, which is Fig. 7a at the point θ = λ / 2 and in Fig. 7b is placed at the position θ = 3λ / 4, it can be seen that the standing wave is spatially (along θ mech ) can be moved. In Fig. 7a the nodes of the fundamental wave are placed above phase c, while in Fig. 7b the nodes of the standing wave are located at the beginning, in the middle, and at the end of the winding arrangement. Since it is a standing wave, the positions of the nodes of the wave are basically constant. A position of the space vector R of the standing wave oscillates in amplitude, but is spatially fixed, ie the spatial coordinates θ(t) of the nodes and / or the space vector are constant in time. The principle of the "moving" standing wave, however, is that the standing wave spatially (along θ mech) can be shifted by controlling or modulating the phase currents that are impressed on the respective phases of the transmitter winding 10. In particular, the (spatial) position of the nodes and / or the space vector of the standing wave can be adjusted by controlling or modulating the phase currents. Thus, unlike a traveling wave, the generated standing wave can be specifically shifted and / or aligned (via the phase currents of the transmitter winding), so that the generated standing wave is also referred to in the present description as a movable or shiftable or alignable standing wave. In particular, the generated standing magnetic field wave can be adjusted or optimized (with respect to a position of the receiver unit or secondary side 20). The magnetic field (B field) generated for energy transmission orThe standing magnetic field wave generated for energy transmission can thus be aligned to a position of the receiver unit 20. The optimization, shifting, and / or alignment of the standing wave is achieved in particular by modulating the amplitudes of the phase currents imposed on the respective phases of the transmitter winding.

[0055] To utilize or "receive" this moving magnetic field of the primary side 10, a single-phase receiver or secondary side winding on the secondary side 20 is suitable, for example, which has a plurality (e.g., two, three, four, five, six, etc.) of windings arranged in a meandering (or D-shaped) pattern. Such a single-phase winding is also referred to in this description as a meandering winding or D-winding due to the meandering or D-shaped windings (regardless of how many D-shaped windings are arranged in a pattern). A meandering winding or D-winding referred to in this description can, for example, comprise two, three, four, five, etc., windings arranged in a meandering or D-shaped pattern. In order to specify the D-winding more precisely with regard to the number of windings arranged in a meandering pattern, for example,If there are two windings arranged in a meandering pattern, this is called a DD winding, if there are three windings arranged in a meandering pattern, this is called a DDD winding, if there are four windings arranged in a meandering pattern, this is called a DDDD winding, and so on.

[0056] The Fig. Figure 8a shows a schematic drawing of a single-phase DDD winding in a perspective view, depicted in the xy plane (2D section plane). As already mentioned above, such a single-phase DDD winding can be arranged, for example, on the secondary side of an inductive power transmission system and used in combination with a moving standing magnetic field wave generated on the primary side of the power transmission system.

[0057] The Fig. Figure 8b shows a schematic drawing of an inductive energy transmission system 100 with a three-phase transmitter unit or primary side 10 and a single-phase receiver unit or secondary side 20 according to a preferred embodiment of the present invention, wherein the transmitter unit 10 and the receiver unit 20 are aligned centered relative to one another. The transmitter unit 10 comprises a three-phase transmitter winding, which is designed to generate a standing wave of a magnetic field used for the inductive energy transmission. The transmitter unit 10 has a length that essentially corresponds to the period length λ of a field harmonic (e.g., fundamental wave or harmonic) of the magnetic field used for energy transmission. The receiver unit or secondary side 20 comprises the Fig. 8a, which is why the secondary side 20 is also referred to as the DDD secondary side in this case. The standing magnetic field wave generated by the three-phase transmitter unit or primary side 10 is aligned with respect to the receiver unit or secondary side 20 such that all half-wave components of the standing wave contribute positively to the flux coupling. Preferably, the D components of the DDD secondary winding (in particular the winding diameters of the windings of the receiver winding) are dimensioned essentially to the node spacing λ / 2 of the standing magnetic field wave generated by the three-phase transmitter unit 10. In other words, the receiver winding of the receiver unit 20 has one or more windings, each having a winding diameter that corresponds essentially to half the period length of the field harmonics of the magnetic field used for energy transmission. As the Fig. As can be seen in Figure 8b, in the example shown, all half-waves of the field harmonics contribute positively to the inductive flux coupling. This is shown in the Fig. 8b by the hatched half-waves marked with a "+." The generated magnetic field is utilized for energy transfer to a much greater extent than with conventional circular or DD windings.

[0058] The Fig. Figure 8c shows a schematic drawing of the inductive energy transfer system 100 of Fig. 8b, where the primary side 10 and the secondary side 20 are not centered relative to each other, but are offset relative to each other in a (maximum permissible) misalignment. The standing magnetic field wave generated by the three-phase transmitter unit or primary side 10 is aligned with respect to the receiver unit or secondary side 20 in such a way that as many half-wave components of the standing wave as possible contribute positively to the flux coupling. In particular, compared to Fig. 8b the nodes of the standing magnetic field wave are adapted to the shifted receiver unit 20. Those half-wave components which contribute positively to the flux coupling are shown in the Fig. 8c is shown hatched and marked with a “+”. In the shifted coil arrangement of the Fig. 8c, only a remaining edge area of the magnetic field cannot be used, resulting in only a slight deviation of the coupling factor compared to the aligned state of the Fig. 8b is to be expected. In order to utilize this part of the field, it is advantageous to extend the secondary side 20 to a DDDD winding (see the Fig. 9a to 9c).

[0059] The Fig. Figure 9a shows a schematic drawing of a single-phase DDDD winding in a perspective view, depicted in the xy plane (2D section plane). As already mentioned above, such a single-phase DDDD winding can be arranged, for example, on the secondary side of an inductive power transmission system and used in combination with a moving standing magnetic field wave generated on the primary side of the power transmission system.

[0060] The Fig. 9b shows a schematic drawing of an inductive energy transmission system 100 with a three-phase transmitter unit or primary side 10 and a single-phase receiver unit or secondary side 20 according to a preferred embodiment of the present invention, wherein the transmitter unit 10 and the receiver unit 20 are aligned centered relative to one another. The transmitter unit 10 comprises a three-phase transmitter winding, which is designed to generate a standing wave of a magnetic field used for the inductive energy transmission. The transmitter unit 10 has a length that essentially corresponds to the period length λ of a field harmonic (e.g. fundamental wave or harmonic) of the magnetic field used for energy transmission. The receiver unit or secondary side 20 comprises the Fig. 9a, which is why the secondary side 20 is also referred to as the DDDD secondary side in this case. The standing magnetic field wave generated by the three-phase transmitter unit or primary side 10 is aligned with respect to the receiver unit or secondary side 20 such that all half-wave components of the standing wave contribute positively to the flux coupling. In particular, the position of the space vector R is adapted to the DDDD receiver winding. Preferably, the D components of the DDDD secondary winding (in particular the winding diameters of the windings of the receiver winding) are dimensioned essentially (i.e. approximately) to the node spacing λ / 2 of the standing magnetic field wave generated by the three-phase transmitter unit 10.In other words, the receiver winding of the receiver unit 20 has one or more turns, each having a turn diameter that essentially corresponds to half the period length of the field harmonics of the magnetic field used for energy transmission. As the . Fig. As can be seen in Figure 9b, in the example shown, all half-waves of the field harmonics contribute positively to the inductive flux coupling. This is shown in the Fig. 9b by the hatched half-waves marked with a "+." The generated magnetic field is utilized for energy transfer to a much greater extent than with conventional circular or DD windings.

[0061] The Fig. 9c shows a schematic drawing of the inductive energy transfer system 100 of Fig. 9b, where the primary side 10 and the secondary side 20 are not centered relative to each other, but are offset from each other in a (maximum permissible) misalignment. The standing magnetic field wave generated by the three-phase transmitter unit or primary side 10 is aligned with respect to the receiver unit or secondary side 20 such that as many half-wave components of the standing wave as possible contribute positively to the flux coupling. In particular, the position of the space vector R is adapted to the DDDD receiver winding. Those half-wave components that contribute positively to the flux coupling are in the Fig. 8c is shown hatched and marked with a “+”. Fig. As can be seen from Figure 9c, in a DDDD receiver winding, even in the shifted positioning of the receiver unit 20, all field components, in particular both edge regions, are utilized for inductive coupling.

[0062] The alignment of the standing magnetic field wave generated by the three-phase transmitter unit 10 with respect to the receiver unit 20 is carried out by means of an adaptation unit which is integrated in the Fig. 8b, 8c, 9b and 9c are not explicitly shown.

[0063] In the examples shown so far, a multi-phase winding was used on the primary side. In fact, however, operation with a single-phase primary side and a multi-phase secondary side is also a valid solution to the task of the present invention. The variant with a single-phase primary side and a multi-phase secondary side is shown in the Fig. 10a and Fig. 10b and is characterized by the fact that no moving standing wave is generated on the primary side 10, but rather a stationary B-field. In this configuration, the coil area of the secondary side 20 is significantly smaller than the coil area of the primary side 10, which is particularly desirable in automotive applications. The induced voltage on the secondary side 20 is distributed position-dependently among the winding phases of the multi-phase secondary side. The extension of the primary side 10 by further D components can increase the permissible positioning range of the secondary side by one half-wave λ / 2. In particular, Fig. 10a shows an inductive energy transmission system 200 with a single-phase primary side 10 comprising a DDD transmitter winding and a three-phase secondary side 20. In the lower part of the Fig. 10a shows the single-phase DDD transmitter winding of the primary side 10 again in a perspective view in the xy plane. Fig. 10b shows an inductive energy transmission system 200 with a single-phase primary side 10 comprising a DDDD transmitter winding and a three-phase secondary side 20. In the lower part of the Fig. 10b shows the single-phase DDDD transmitter winding of the primary side 10 again in a perspective view in the xy plane. Furthermore, in the Fig. 10a and Fig. 10b shows a permissible positioning range P in each case, in which the receiver unit 20 can be located relative to the transmitter unit 10 without significantly changing or reducing the inductive coupling. Expanding the transmitter winding from a DDD to a DDDD arrangement increases the permissible positioning range P by one half-wave D = λ / 2.

[0064] The reversal of the roles of transmitter and receiver also demonstrates the potential of the transmission principle described here for bidirectional contactless energy transmission. This also applies to a multi-phase design of the transmission windings on both sides. With regard to the aforementioned disadvantages of previous multi-phase or three-phase traveling wave systems, it should be emphasized at this point that the flux density in the edge area of the coil system can be specifically controlled and thus reduced to a minimum by adjusting the position of the nodes of the moving standing wave.

[0065] The (moving) standing magnetic field wave can be generated by adjusting all phase currents of the multiphase transmitter unit to be in phase. Furthermore, the standing magnetic field wave can be aligned by adjusting the amplitudes of the in-phase phase currents to the respective position of the receiver unit (e.g., to a parking position of an electric vehicle in which the receiver unit is installed). In this way, a field-oriented standing magnetic field wave can be generated. The resulting standing space vector of the B field changes its amplitude with the frequency of the phase currents. For the definition of in-phase phase currents, refer to equations (1) to (4) given above.

[0066] The Fig. Figure 11a shows a schematic drawing of a planar arrangement of geometrically distributed windings and associated exemplary fundamental wave space vectors per phase flux density for a symmetrical three-phase winding. And the Fig. Figure 11b shows a schematic drawing of a planar arrangement of geometrically distributed windings and associated exemplary fundamental wave space vectors per phase flux density for a general multiphase winding.

[0067] Due to an electrical connection in star, delta or zigzag form, the following constraint applies to the modulation of the phase currents: ∑n=1Nin(t)=0, with N=max NPhase

[0068] For a three-phase winding, the following constraint applies: ia(t)=+ib(t)+ic(t)=0

[0069] Within the scope of the invention, the multiphase windings can be arranged in a translatory or rotary manner. To better illustrate the space vector composition, the rotary analogue is useful, which is shown in the Fig. 11c and Fig. 11d. The Fig. Figure 11c shows a schematic diagram of the space vector addition of geometrically distributed phase flux densities for a symmetric three-phase system. And the Fig. Figure 11d shows a schematic diagram for the space vector addition of geometrically distributed phase flux densities for a general multiphase system. The general multiphase system does not necessarily have to be geometrically symmetrical, i.e., evenly distributed. An asymmetrical conductor arrangement affects the modulation of the phase currents.

[0070] In general, the planar arrangements shown can be converted into the rotary arrangement according to the Fig. 11c and Fig. 11d. The term “periodic cascading” refers to a periodic repetition and / or continuation and / or stringing together of the strands to increase the number of periods (e.g., in Fig. 4 the arrangement of the strands +a, -c, +b, -a, +c, -b can be continued periodically to: +a, -c, +b, -a, +c, -b, +a, -c, +b, etc.). For the translational arrangement with period number 1 (as in the Fig. 11a and Fig. 11b) edge effects occur which can be taken into account in the geometric design of a secondary side. In the context of this description, the term "period number" refers to the number of period lengths of the field harmonics used for energy transfer. The amplitudes of the phase currents according to equation (1) can be determined by an inverse space vector composition (i.e., generally by inverting the dq quantities in a multi-phase system), as described in Fig. 12a. This procedure corresponds to a field-oriented modulation (FOC), whereby the desired current waveform to be used for energy transfer is impressed on the d-axis (receiver-oriented). The q-axis does not contribute to this (idealized). Using an inverse Park transformation (dq & Clarke-T.), the receiver-oriented coordinate system is transformed to the primary side. The local position dependence is determined by the positioning of the secondary side (using the position variable θ mech ) is shown.

[0071] In the following, an exemplary procedure is described to adapt the phase currents (especially their amplitudes) of a three-phase transmitter unit or transmitter coil to the location variable θ mechThe mathematical background goes back to the theory of controlling rotating field machines using field-oriented control (FOR), vector control, or field-oriented control (FOC). The Clarke & Park transformation is used to convert the quantities of a three-phase system to a simpler two-axis coordinate system. The application of both transformations is often referred to as the "dq transformation" and maps the phase quantities (especially currents, voltages, magnetic fluxes) to the two orthogonal axes "d" and "q," or to the so-called "dq coordinate system."

[0072] The Fig. The vector diagram shown in Figure 12b shows the phases geometrically shifted by 120° (i.e., λ / 3), as well as the dq coordinate system rotated by θ relative to the a-axis. In the dq transformation, the phase variables (e.g., phase currents) are vectorially added. The resulting vector is then projected onto the d- or q-axis using vector decomposition. Applied to the inductive energy transfer system described herein, the position of the dq coordinate system depends on the position of the receiver unit or receiver coil. To derive the phase variables or phase currents from the dq coordinate system, an inverse dq transformation is applied. The general inverse dq transformation for a (symmetrical) three-phase system is: (iaibic)=(cos(θmech)−sin(θmech)cos(θmech−2π3)−sin(θmech−2π3)cos(θmech−4π3)−sin(θmech−4π3))(id,modiq)

[0073] Accordingly Fig. 12a the desired current i d,mod = î d· sin(ωt) is modulated onto the d-axis and i q set to “0”: (ia(θmech,t)ib(θmech,t)ic(θmech,t))=(cos(θmech)−sin(θmech)cos(θmech−2π3)−sin(θmech−2π3)cos(θmech−4π3)−sin(θmech−4π3))(i^d⋅sin(ωt)0)

[0074] This equation can be simplified to: (ia(θmech,t)ib(θmech,t)ic(θmech,t))=(cos(θmech)cos(θmech−2π3)cos(θmech−4π3))l^d⋅sin(ωt)

[0075] Consequently, the phase currents are determined by the following equations: {ia(θmech,t)=l^d⋅cos(θmech) sin(ωt)ib(θmech,t)=l^d⋅cos(θmech−2π3)) sin(ωt)ic(θmech,t)=l^d⋅cos(θmech−4π3)) sin(ωt)

[0076] The position of the secondary side goes over the angle θ mech into the phase modulation. In general, for multiphase systems with N ≠ 3, an inverse space vector composition can be used to convert the dq quantities into the corresponding phase quantities.

[0077] The Fig. Figure 13a shows a schematic drawing of a simplified exemplary primary-side air-gap magnetic field with pronounced harmonics. Within the scope of the present invention, it has been found that it is advantageous to select the geometric dimensions of the transmitter and / or receiver unit based on the period length of the fundamental wave or any field harmonic to be used for energy transmission. Fig. 13b shows a schematic drawing of the design of the secondary side using the fundamental wave (first harmonic). And the Fig.13c shows a schematic drawing for the design of the secondary side using a harmonic (here the third harmonic). In particular, a length of the transmitter unit and / or a length of the receiver unit essentially corresponds to the period length of a fundamental or harmonic of a magnetic field used for energy transmission. In particular, the secondary side or the receiver unit is designed such that a turn spacing of the receiver winding essentially corresponds to half the period length of a fundamental or harmonic of the magnetic field used for energy transmission. In particular, the turns of the receiver winding are designed or (geometrically) dimensioned with respect to (or based on) the node spacing of the magnetic field used for energy transmission or the magnetic field harmonics used for energy transmission.

[0078] The present invention relates in particular to the improvement of inductive charging systems. It goes beyond the conventional approach of magnetic coupling and specifically integrates the use of multiphase inductive energy transfer using field-oriented standing waves. This concept serves to address the inherent limitations of conventional systems, which typically consist of energy losses and a complex geometric alignment of the components involved. Single-phase systems are usually used in conventional inductive energy transfer. The introduction of a multiphase system means that energy is transferred across multiple phases or oscillations. This leads, in particular, to energy transfer becoming more efficient and less susceptible to interference and losses.In the field-oriented standing wave concept described herein, the electromagnetic fields can be aligned to concentrate them in specific areas, known as "standing waves." This alignment can help to transmit energy more precisely and minimize losses due to scattering or absorption. The transmitter (primary side) and receiver (secondary side) units can each be adapted to generate and efficiently utilize these standing waves. In particular, with the help of an intelligent energy transfer protocol, it is possible to dynamically adjust the phase sizes (such as amplitudes and frequencies) of the transmitted energy. The system can be equipped with integrated sensors and control mechanisms that enable continuous monitoring and adjustment of the energy transfer efficiency.This allows users to receive real-time feedback, and the system can use self-learning algorithms to further optimize efficiency. Compared to conventional inductive charging systems, the invention offers several advantages: Energy transfer is more efficient, as less energy is lost, particularly due to the field-oriented standing waves. Furthermore, the need for precise geometric alignment of the coupling elements can be reduced, which increases user-friendliness. Finally, the use of a multi-phase system can increase the overall efficiency and reliability of the system. It is understood that the application of the present invention is not limited to charging systems. For example, the invention can also be used in electrical machines for rotor excitation. List of reference symbols 2 Vehicle floor 4 Edge area / sill area 10 Transmitter unit (primary side) 20 Receiver unit (secondary side) 100 Energy transmission system 200 energy transmission system R space vector P Permissible positioning range

Claims

[1] Method for the inductive transmission of electrical energy from a transmitter unit (10) to a receiver unit (20) of an inductive energy transmission system (100), comprising: - generating a standing wave of a magnetic field used for the inductive energy transmission by means of a multi-phase transmitter winding of the transmitter unit (10), wherein the standing wave is adapted to a relative position of the transmitter winding and a receiver winding of the receiver unit (20). [2] Method according to claim 1, wherein, in order to generate the standing wave, a respective associated phase current is impressed on each of a plurality of phases of the multi-phase transmitter winding, wherein all phase currents have the same electrical phase. [3] Method according to claim 1 or 2, wherein the standing wave is adjusted by adjusting amplitudes of in-phase phase currents applied to the multi-phase transmitter winding. [4] Method according to claim 3, wherein the amplitudes of the in-phase phase currents are adjusted such that a coupling between the transmitter unit (10) and the receiver unit (20) is maximum. [5] A method according to any one of the preceding claims, comprising the step: - Providing the inductive energy transmission system (100), wherein a total length of the multi-phase transmitter winding of the energy transmission system (100) and / or a total length of the receiver winding of the energy transmission system (100) substantially corresponds to a period length of the standing magnetic field wave generated for energy transmission. [6] A method according to any one of the preceding claims, comprising the step: - Providing the inductive energy transmission system (100), wherein the receiver winding has one or more turns, each with a turn diameter that substantially corresponds to half the period length of a fundamental or harmonic wave of the magnetic field used for energy transmission. [7] A method according to any one of the preceding claims, comprising the step: - Providing the inductive energy transmission system (100), wherein the transmitter winding is a three-phase winding, and wherein the receiver winding is a single-phase winding, in particular a DDD or DDDD winding. [8] Inductive energy transfer system (100) comprising: - a transmitter unit (10) with a multi-phase transmitter winding designed to generate a standing wave of a magnetic field used for inductive energy transmission; - a receiver unit (20) with a single-phase or multi-phase receiver winding; and - an adaptation unit which is designed to adapt the standing wave to a relative position of the transmitter winding and the receiver winding. [9] Transmitter system for inductive transmission of electrical energy, comprising: - a transmitter unit (10) with a multi-phase transmitter winding, which is designed to generate a standing wave of a magnetic field used for the inductive energy transmission; and - an adaptation unit which is designed to adapt the standing wave to a position of the transmitter winding relative to a receiver winding. [10] Method for producing an inductive energy transmission system (100; 200), comprising the steps: - providing a transmitter unit (10) for generating a magnetic field used for energy transmission; and - Providing a receiver unit (20) for generating an induced voltage and / or an induced current based on the magnetic field generated by the transmitter unit (10); characterized by that a total length and / or at least one winding diameter of a receiver winding of the receiver unit (20) is / will be matched to a period length of a fundamental or harmonic wave of the magnetic field generated by the transmitter unit (10). [11] The method of claim 10, wherein the total length of the receiver winding is matched to the magnetic field generated by the transmitter unit (10) in such a way that the total length of the receiver winding essentially corresponds to the period length of a fundamental or harmonic wave of the magnetic field generated by the transmitter unit; and / or the at least one winding diameter of the receiver winding is matched to the magnetic field generated by the transmitter unit (10) in such a way that the at least one winding diameter of the receiver winding substantially corresponds to half the period length of a fundamental or harmonic wave of the magnetic field generated by the transmitter unit. [12] Inductive energy transfer system (100; 200) comprising: - a transmitter unit (10) for generating a magnetic field used for energy transmission; and - a receiver unit (20) with a receiver winding; characterized by , that: a total length of the receiver winding substantially corresponds to a period length of a fundamental or harmonic wave of the magnetic field generated by the transmitter unit (10); and / or at least one winding diameter of the receiver winding corresponds substantially to half a period length of a fundamental or harmonic wave of the magnetic field generated by the transmitter unit (10). [13] Inductive energy transmission system (200) according to claim 12, wherein the transmitter unit (10) comprises a transmitter winding with one or more turns, wherein a turn diameter of each of the one or more turns corresponds substantially to half the period length of a magnetic field wave used for energy transmission. [14] Inductive charging system for electric vehicles comprising an energy transmission system (100; 200) according to one of claims 8, 12 and 13.

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