Method for Wirelessly Transmitting Electric Energy, Energy Transmitting Device, and System Consisting of Energy Transmitting Devices

Abstract

A method for wirelessly transmitting electric energy to an energy receiving device using at least one energy transmitting device, in particular an induction transmission device. The method includes wirelessly transmitting electric energy to the energy receiving device via at least one voltage signal using at least one resonant circuit of the at least one energy transmitting device, and pausing the transmission of the at least one voltage signal, in particular at regular intervals, in order to detect foreign bodies and/or for communication between the at least one energy transmitting device and the energy receiving device and/or an external unit. The method further includes ascertaining over time at least one point in time of the transmission pauses of the at least one voltage signal on the basis of at least one external reference signal, in particular a reference signal which is independent of the energy receiving device, using at least one control and/or regulating unit of the at least one energy transmitting device.

Claims

1. A method for wirelessly transmitting electrical energy to an energy reception device using at least one energy transmission device, comprising: wirelessly transmitting electrical energy to the energy reception device by way of at least one oscillating circuit of the at least one energy transmission device using at least one voltage signal; pausing the transmission of the at least one voltage signal, at regular time intervals, to detect foreign bodies and/or to allow the at least one energy transmission device to communicate with the energy reception device and/or with an external unit; and temporarily ascertaining at least one time of the transmission pauses of the at least one voltage signal based on at least one external reference signal independent of the energy reception device using at least one control and/or regulation unit of the at least one energy transmission device.

2. The method as claimed in claim 1, further comprising: adapting the at least one voltage signal based on the ascertained at least one time of the transmission pauses using the at least one control and/or regulation unit.

3. The method as claimed in claim 1, further comprising: detecting and processing at least one temporal profile of the at least one external reference signal by way of the at least one control and/or regulation unit to ascertain the at least one time of the transmission pauses of the at least one voltage signal.

4. The method as claimed in claim 1, wherein the at least one external reference signal is based on a time of a minimum or of a maximum of an AC voltage of a supply grid of the at least one energy transmission device.

5. The method as claimed in claim 1, wherein the at least one external reference signal is based on an interference signal that is overlaid on the at least one voltage signal.

6. The method as claimed in claim 5, further comprising: detecting the at least one external reference signal using the at least one control and/or regulation unit during the transmission pauses of the at least one voltage signal.

7. The method as claimed in claim 6, further comprising: detecting the at least one external reference signal by way of the at least one control and/or regulation unit through a comparison of the at least one voltage signal with at least one reference pattern.

8. The method as claimed in claim 6, further comprising: detecting the at least one external reference signal by way of the at least one control and/or regulation unit through a comparison of quality characteristic values, determined and/or calculated by way of the at least one control and/or regulation unit, of the at least one oscillating circuit during at least two successive transmission pauses of the at least one voltage signal.

9. The method as claimed in claim 5, further comprising: adapting the at least one voltage signal by way of the at least one control and/or regulation unit using at least one algorithm, such that the time of the transmission pauses of the at least one voltage signal corresponds at least substantially to a time of a minimum of the interference signal.

10. The method as claimed in claim 1, further comprising: synchronizing the ascertained time of the transmission pauses of the at least one voltage signal with at least one external unit by way of at least one communication unit of the at least one energy transmission device.

11. The method as claimed in claim 1, wherein the method is performed by the at least one energy transmission device for wirelessly transmitting electrical energy to the energy reception device in order to charge a rechargeable battery.

12. A system comprising: at least one energy transmission device including at least one oscillating circuit and at least one control and/or regulation unit, the at least one energy transmission device configured to wirelessly transmit electrical energy to an energy reception device by: wirelessly transmitting electrical energy to the energy reception device by way of the at least one oscillating circuit using at least one voltage signal; pausing the transmission of the at least one voltage signal, at regular time intervals, to detect foreign bodies and/or to allow the at least one energy transmission device to communicate with the energy reception device and/or with an external unit; and temporarily ascertaining at least one time of the transmission pauses of the at least one voltage signal based on at least one external reference signal independent of the energy reception device using the at least one control and/or regulation unit, wherein the transmission pauses of the at least one voltage signal of the at least one energy transmission device are temporally synchronized based on at least one external reference signal.

Description

DRAWINGS

[0024] Further advantages will become apparent from the following description of the drawing. The drawings illustrate three exemplary embodiments of the invention.

[0025] The drawings, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features on their own and combine them to form expedient further combinations.

[0026] In the figures:

[0027] FIG. 1 shows a schematic illustration of a system according to the invention consisting of multiple energy transmission devices according to the invention for performing a method according to the invention for wirelessly transmitting electrical energy to an energy reception device of the system by way of one of the energy transmission devices,

[0028] FIG. 2 shows a basic sketch of a circuit diagram of one of the energy transmission devices according to the invention and of the energy reception device,

[0029] FIG. 3 shows a schematic illustration of a sequence of the method according to the invention for wirelessly transmitting electrical energy to the energy reception device by way of one of the energy transmission devices according to the invention,

[0030] FIG. 4 shows a schematic illustration of two voltage signals from two energy transmission devices synchronized by way of the method according to the invention,

[0031] FIG. 5 shows a schematic illustration of a sequence of an alternative configuration of a method according to the invention for wirelessly transmitting electrical energy to an energy reception device by way of an energy transmission device according to the invention,

[0032] FIG. 6 shows a schematic illustration of two voltage signals from two energy transmission devices according to the invention, wherein the two voltage signals are overlaid, and

[0033] FIG. 7 shows a schematic illustration of two voltage signals from two energy transmission devices synchronized by way of the alternative configuration of the method according to the invention.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0034] FIG. 1 shows a system 10a consisting of three energy transmission devices 12a, wherein transmission pauses 62a of voltage signals 58a (cf. FIG. 4) of the energy transmission devices 12a are temporally synchronized on the basis of an external reference signal 72a (cf. FIG. 4). The energy transmission devices 12a are each in the form of a smart kitchen device, wherein the energy transmission devices 12a are in particular networked to one another via communication units 14a. Other configurations of the system 10a and/or of the energy transmission devices 12a, independently of the communication units 14a, are however also conceivable. The energy transmission devices 12a are in the form of induction transmission devices, in particular induction chargers. The system 10a preferably comprises three energy reception devices 16a in the form of smart kitchen devices, which are in particular respectively in the form of a rechargeable battery and/or rechargeable-battery-operated device. The energy transmission devices 12a are in particular intended to wirelessly transmit electrical energy to in each case one of the energy reception devices 16a. Each of the energy transmission devices 12a preferably comprises a transmission coil 18a. Each of the energy reception devices 16a in particular comprises a receiver coil 20a. The receiver coil 20a and the transmission coil 18a are preferably designed to be inductively coupled to one another during a transmission process of the energy reception device 16a by way of the energy transmission device 12a. In FIG. 1, the energy reception devices 16a are each arranged on one of the energy transmission devices 12a, wherein in particular a transmission process takes place. The energy transmission devices 12a each comprise at least one device receptacle 22a that is designed to at least partially receive at least one of the energy reception devices 16a in order to transmit electrical energy. The device receptacles 22a, in at least one operating state, in particular during a transmission process, preferably at least partially each define a gap 24a between the energy transmission device 12a and the energy reception device 16a. The transmission coil 18a is in particular arranged in the device receptacle 22a. The system 10a, in particular the individual energy transmission devices 12a, is preferably intended to perform a method 100a for wirelessly transmitting electrical energy to one of the energy reception devices 16a.

[0035] The energy transmission devices 12a are preferably in each case individually electrically connected to a supply grid 26a, wherein the energy transmission devices 12a are operated with a grid voltage 64a (cf. FIG. 4). The energy transmission devices 12a each have an oscillating circuit 28a (cf. FIG. 2), which comprises the transmission coil 18a, a capacitor 30a and an electrical resistor, wherein the electrical resistor is in particular in the form of an electrical resistance of line elements of the oscillating circuit 28a. The energy transmission devices 12a each have a control circuit 34a (cf. FIG. 2) that is intended to excite the oscillating circuit 28a. The oscillating circuit 28a is preferably designed to be excited with the grid voltage 64a by way of the control circuit 34a via a control signal, wherein a voltage signal 58a is in particular generated. The energy transmission devices 12a each have a control and/or regulation unit 36a, which comprises a storage unit 38a (cf. FIG. 2). The energy transmission devices 12a, in particular the oscillating circuits 28a, are in particular each designed to wirelessly transmit energy to the energy reception device 16a using the voltage signal 58a. The oscillating circuit 28a, in particular the transmission coil 18a, preferably generates a magnetic alternating field using the voltage signal 58a, which magnetic alternating field induces a current in the receiver coil 20a of the energy reception device 16a. Electrical energy is in particular transmitted from the energy transmission device 12a to the energy reception device 16a by way of the magnetic alternating field. The energy transmission device 12a, in particular the control and/or regulation unit 36a, is preferably designed to generate the transmission pauses 62a in the voltage signal 58a, in particular at regular time intervals, wherein in particular the transmission pauses 62a of the voltage signal 58a are intended to allow detection of foreign bodies in the gap 24a and/or to allow the energy transmission device 12a to communicate with the energy reception device 16a and/or with an external unit 40a, such as for example a server or a monitoring unit of the system 10a. The energy transmission device 12a, in particular the control and/or regulation unit 36a, is particularly preferably designed to temporally ascertain the at least one time of the transmission pauses 62a of the voltage signal 58a on the basis of the external reference signal 72a, which is in particular independent of the energy reception device 16a. The external reference signal 72a is preferably designed to be independent of the energy transmission unit 12a and the energy reception device 16a, wherein the external reference signal 72a is in particular generated within the supply grid 26a. In the configuration shown in FIG. 1, the external reference signal 72a is in the form of a time of a minimum or of a maximum of the in particular rectified AC voltage of the supply grid 26a of the energy transmission device 12a. The energy transmission devices 12a are particularly preferably designed to synchronize the time of the transmission pauses 62a with the respective other energy transmission devices 12a using the external reference signal 72a and/or using the communication unit 14a.

[0036] The energy transmission devices 12a each have a detection unit 42a and one of the communication units 14a, which are in particular connected to one of the control and/or regulation units 36a. The communication units 14a are preferably each designed, during the transmission pauses 62a, to transmit electronic data 44a to one of the energy reception devices 16a and/or one of the other energy transmission devices 12a and/or to receive electronic data 44a from one of the energy reception devices 16a and/or one of the other energy transmission devices 12a. By way of example, the communication unit 14a is designed to communicate a state, in particular a state of charge, of the energy reception device 16a to the energy transmission device 12a via the data transmission. As an alternative or in addition, it is conceivable for the communication unit 14a to be designed to communicate a state of the energy reception device 16a and/or of the energy transmission device 12a to the external unit 40a, such as for example a server and/or a monitoring unit, via the data transmission. The communication units 14a are each in the form of an NFC device, wherein the communication units 14a preferably each comprise an NFC communication coil 46a. Other configurations of the communication unit 14a are however also conceivable, for example as a Bluetooth device, as a W-LAN device, as a PLC device or the like. The data transmission preferably takes place in accordance with at least one standard, in particular the QI standard, from the Wireless Power Consortium (WPC). The detection units 42a are in particular each in the form of part of one of the control and/or regulation units 36a and designed to detect foreign bodies in the gap 24a on the basis of a temporal profile of a quality characteristic value of a transmission system 48a consisting of oscillating circuit 28a and energy reception device 16a. The detection units 42a are preferably each intended to ascertain and to evaluate the temporal profile of the quality characteristic value during the transmission pauses 62a. The foreign body identification preferably takes place by way of the detection unit 42a in accordance with at least one standard, in particular the QI standard, from the Wireless Power Consortium (WPC).

[0037] All of the energy transmission devices 12a of the system 10a are connected to exactly one external conductor of the supply grid 26a, this in particular not being shown in the figures. However, it is also conceivable for the energy transmission devices 12a each to be connected to more than one external conductor of the supply grid 26a, wherein in particular exactly one of the external conductors is used to ascertain the time of the transmission pauses 62a. All of the energy transmission devices 12a of the system 10a are connected to the same external conductor of the supply grid 26a, wherein in particular the times of the minimum or of the maximum of the AC voltage of the supply grid 26a are the same for all energy transmission devices 12a. The transmission pauses 62a of the voltage signals 58a of the energy transmission devices 12a are preferably synchronized, in particular by the communication units 14a, via an external conductor, used to ascertain the time of the transmission pauses 62a, of the supply grid 26a. It is conceivable for the energy transmission device 12a to comprise an input and/or output unit 49a that is designed for a user to control the energy transmission device 12a, in particular to activate and/or deactivate a calibration mode and/or for a query as to whether a foreign body is in the gap 24a. For example, the input and/or output unit 49a is in the form of a touch display. However, other configurations of the input and/or output unit 49a are conceivable, for example as a keypad, as a microphone or the like.

[0038] FIG. 2 shows one of the energy transmission devices 12a and one of the energy reception devices 16a, in particular during a transmission process, in the form of a basic sketch. Circuit diagrams of the energy transmission device 12a and of the energy reception device 16a are illustrated schematically in FIG. 2. The control circuit 34a of the energy transmission device 12a has at least one driver element 50a and at least one further driver element 52a. However, it is also conceivable for the control circuit 34a to comprise just one driver element 50a, 52a. The driver element 50a, in particular in relation to the oscillating circuit 28a, is in the form of a high-side driver and the further driver element 52a, in particular in relation to the oscillating circuit 28a, is in the form of a low-side driver. The driver element 50a and/or the further driver element 52a are/is in the form of one or more metal oxide semiconductor field-effect transistors, in particular so-called MOSFETs. However, other configurations of the driver element 50a and/or the further driver element 52a are also conceivable, for example as one or more insulated-gate bipolar transistors, in particular so-called IGBTs. The control circuit 34a is electrically connected to the control and/or regulation unit 36a and the oscillating circuit 28a. The energy transmission devices 12a in particular each have a rectifier 55a for rectifying the AC voltage of the supply grid 26a, wherein the rectifier 55a is in particular electrically connected to the control circuit 34a and is connected to the supply grid 26a. The rectified AC voltage is preferably present at the driver element 50a and the further driver element 52a, wherein the oscillating circuit 28a is excited by the rectified AC voltage in the event of switching of the driver element 50a, in particular by way of the control and/or regulation unit 36a. The NFC communication coil 46a of the communication unit 14a of the energy transmission device 12a is shown schematically in FIG. 2. It is conceivable for the communication unit 14a, in particular the NFC communication coil 46a, to be electrically connected to the control and/or regulation unit 36a. The energy reception device 16a comprises the receiver coil 20a, a capacitor 53a, a rectifier 54a, which is in particular formed of four diodes, and an energy storage unit 56a, for example a rechargeable battery cell. The energy reception device 16a in particular comprises at least one communication unit 57a, which in particular comprises an NFC communication coil 59a for data transmission with the communication coil 46a of the communication unit 14a of the energy transmission device 12a. The rectifier 54a is designed to convert an AC voltage generated by way of the AC current induced by the magnetic alternating field into a DC voltage, which is in particular present at the energy storage unit 56a. However, other configurations of the energy transmission device 12a and/or of the energy reception device 16a are also conceivable. By way of example, it is conceivable for the energy reception device 16a, instead of or in addition to the energy storage unit 56a, to comprise an energy consumption unit, such as for example a motor, a display or the like, which is in particular operated by way of the transmitted electrical energy.

[0039] FIG. 3 shows an exemplary sequence of the method 100a for wirelessly transmitting electrical energy to one of the energy reception devices 16a by way of one of the energy transmission devices 12a. In at least one method step 102a of the method 100a, electrical energy is wirelessly transmitted to the energy reception device 16a by way of the oscillating circuit 28a of the energy transmission device 12a using the voltage signal 58a. In at least one further method step 104a of the method 100a, in particular at regular time intervals, transmission pauses 62a of the voltage signal 68a take place in order to detect foreign bodies and/or to allow the energy transmission device 12a to communicate with the energy reception device 16a and/or with the external unit 40a. In particular, in at least one method step of the method 100a, in particular method step 104a, the repetition rate of the transmission pauses 62a is determined by way of the control and/or regulation unit 36a, in particular on the basis of the grid voltage 64a, the energy transmission device 12a and/or the energy reception device 16a. It is conceivable for the repetition rate of the transmission pauses 62a to be kept constant by way of the control and/or regulation unit 36a during a transmission process. At least one foreign object identification is preferably performed during the transmission pauses 62a by way of the energy transmission device 12a, in particular the detection unit 42a of the energy transmission device 12a. At least one data transmission preferably takes place between the energy transmission device 12a and the energy reception device 16a and/or the external unit 40a during the transmission pauses 62a by way of the energy transmission device 12a, in particular the communication unit 14a of the energy transmission device 12a.

[0040] In at least one further method step 106a of the method 100a, at least one time of the transmission pauses 62a of the voltage signal 58a is temporally ascertained on the basis of the at least one external reference signal 72a, which is in particular independent of the energy reception device 16a, by way of the control and/or regulation unit 36a of the energy transmission device 12a. The external reference signal 72a is in the form of a time of a minimum or of a maximum of the in particular rectified AC voltage of the supply grid 26a of the energy transmission device 12a. Preferably, the time of the transmission pauses 62a is temporally ascertained before a beginning of a transmission process and/or during a transmission process of the energy reception device 16a. The time of the transmission pauses 62a of the voltage signal 58a is preferably ascertained on the basis of the at least one time of the minimum or of the maximum of the in particular rectified AC voltage. The AC voltage is in particular rectified in at least one method step of the method 100a, in particular method step 106a, by way of the rectifier 55a of the energy transmission device 12a, wherein the minimum of the rectified AC voltage is in the form of a zero crossing of the AC voltage of the supply grid 26a. In at least one method step of the method 100a, in particular method step 106a, exactly one external conductor, in particular one phase, of the supply grid 26a is preferably selected by way of the control and/or regulation unit 36a for ascertaining the time of the transmission pauses 62a and for exciting the oscillating circuit 28a and/or predefined for ascertaining the time of the transmission pauses 62a and for exciting the oscillating circuit 28a when the energy transmission device 12a is manufactured.

[0041] In at least one further method step 108a of the method 100a, the voltage signal 58a is adapted on the basis of the ascertained time of the transmission pauses 62a by way of the control and/or regulation unit 36a. The voltage signal 58a is preferably adapted such that the voltage signal 58a is suspended, interrupted and/or throttled at the ascertained time of the transmission pauses 62a, wherein in particular an amplitude of the voltage signal 58a in the transmission pauses 62a is reduced in comparison with a transmission process outside the transmission pauses 62a. In particular, at the ascertained time of the transmission pauses 62a, an energy transfer from the energy transmission device 12a to the energy reception device 16a is at least substantially suspended. By way of example, at the ascertained time of the transmission pauses 62a, excitation of the oscillating circuit 28a by the control circuit 34a is suspended by way of the control and/or regulation unit 36a. As an alternative or in addition, it is conceivable for the oscillating circuit 28a to be damped at the ascertained time of the transmission pauses 62a, in particular by introducing an electrical resistance into the oscillating circuit 28a. The voltage signal 58a is preferably adapted by way of the control and/or regulation unit 36a such that the transmission pauses 62a temporally comprise the time of the minimum of the AC voltage of the supply grid 26a, in particular the grid voltage 64a, of the energy transmission device 12a. The voltage signal 58a is in particular adapted by way of the control and/or regulation unit 36a such that the time of the minimum of the AC voltage is arranged temporally at least substantially centrally within the ascertained time of the transmission pauses 62a, wherein in particular the time of the minimum is temporally arranged in particular at least 40%, preferably at least 45% and particularly preferably at least 48% of an overall duration of the transmission pauses 62a in each case after a beginning of the transmission pauses 62a. The voltage signal 58a is preferably adapted by way of the control and/or regulation unit 36a such that the time of the minimum is temporally arranged in particular at least 40%, preferably at least 45% and particularly preferably at least 48% of an overall duration of the transmission pauses 62a in each case before an end of the transmission pauses 62a.

[0042] In at least one further method step 110a of the method 100a, at least one temporal profile of the external reference signal 72a is detected and processed by way of the control and/or regulation unit 36a in order to ascertain the time of the transmission pauses 62a of the voltage signal 58a. The temporal profile of the external reference signal 72a is preferably detected by way of the control and/or regulation unit 36a using at least one signal characteristic variable, in particular an amplitude, a frequency and/or a wavelength, of the voltage signal 58a, wherein the external reference signal 72a in particular influences the signal characteristic variable of the voltage signal 58a. The signal characteristic variable is preferably detected and plotted over at least one time interval in order to ascertain the temporal profile of the external signal 72a. Particularly preferably, the time interval is in the form of one of the transmission pauses 62a of the voltage signal 58a. As an alternative or in addition, it is conceivable for the temporal profile of the external reference signal 72a to be detected by way of at least one sensor unit of the energy transmission device 12a and transmitted to the control and/or regulation unit 36a. It is conceivable for the external reference signal 72a to be detected preferably directly by the control and/or regulation unit 36a, wherein in particular the grid voltage 64a present at the energy transmission device 12a, in particular at the control and/or regulation unit 36a, is detected. The temporal profile of the external reference signal 72a for ascertaining the time of the transmission pauses 62a of the voltage signal 58a particularly preferably comprises at least one period length of the external reference signal 72a. Preferably, when processing the temporal profile in order to ascertain the time of the transmission pauses 62a of the voltage signal 58a, at least one time of a minimum of the temporal profile is determined by way of the control and/or regulation unit 36a. The voltage signal 58a is in particular adapted by way of the control and/or regulation unit 36a such that the transmission pauses 62a temporally comprise the time of the minimum of the temporal profile of the external reference signal 72a.

[0043] In at least one further method step 112a of the method 100a, the ascertained time of the transmission pauses 62a of the voltage signal 58a is synchronized with the external unit 40a or another energy transmission device 12a of the system 10a by way of the communication unit 14a. The energy transmission device 12a is preferably synchronized with the external unit 40a or the other energy transmission device 12a of the system 10a via NFC, Bluetooth, W-LAN, PLC or the like. In particular, in at least one method step of the method 100a, preferably method step 112a, a communication request is output to external units 40a located in the vicinity of the energy transmission device 12a or other energy transmission devices 12a of the system 10a, by way of the communication unit 14a, in particular periodically or continuously, in particular in order to synchronize transmission pauses 62a. Preferably, in order to synchronize the energy transmission device 12a with the external unit 40a or the other energy transmission device 12a of the system 10a by way of the communication unit 14a, a duration 70a (cf. FIG. 4) and the repetition rate of the transmission pauses 62a of the voltage signal 58a are transmitted to the external unit 40a or the other energy transmission device 12a of the system 10a. In particular, in method step 112a of the method 100a, an external conductor, connected to the energy transmission device 12a and/or used to ascertain the time of the transmission pauses 62a of the voltage signal 58a, of the supply grid 26a is preferably transmitted to the external unit 40a or the other energy transmission device 12a of the system 10a by way of the communication unit 14a in order to synchronize the energy transmission device 12a with the external unit 40a or the other energy transmission device 12a of the system 10a. In particular, in method step 112a of the method 100a, transmission pauses 62a of the other energy transmission device 12a of the system 10a and of the energy transmission device 12a are synchronized by the communication unit 14a.

[0044] FIG. 4 shows a schematic illustration of a temporal profile of two voltage signals 58a, 60a from two energy transmission devices 12a of different design. The two energy transmission devices 12a are supplied in particular via different grid voltages 64a, 66a. In particular, a first energy transmission device 12a is operated with a grid voltage 64a in the form of an AC voltage and a second energy transmission device 12a is operated with a grid voltage 66a in the form of a DC voltage. The voltage signals 58a, 60a, in particular the frequency of the voltage signals 58a, 60a, are shown schematically in FIG. 4 and have an abstract relationship in relation to the transmission pauses 62a and the grid voltages 64a, 66a of the supply grids 26a of the energy transmission devices 12a in order to clarify the illustration. A time is in particular plotted on the abscissas shown in FIG. 4. A signal strength is preferably plotted on the ordinates shown in FIG. 4. The repetition rate of the transmission pauses 62a preferably corresponds to a value from a range of values of in particular 40 Hz to 200 Hz, preferably 60 Hz to 150 Hz and particularly preferably 100 Hz to 120 Hz. The voltage signals 58a, 60a preferably have a frequency that corresponds in particular to at least 1 kHz, preferably at least 10 kHz and particularly preferably at least 80 kHz. The grid voltage 64a, in the form of an AC voltage, preferably has a frequency that corresponds to a value from a range of values of in particular 20 Hz to 100 Hz, preferably 30 Hz to 75 Hz and particularly preferably 50 Hz to 60 Hz. The time of the transmission pauses 62a of the voltage signal 58a of the first energy transmission device 12a is ascertained by way of the method 100a described in FIG. 3. The time of the transmission pauses 62a of the voltage signal 58a of the first energy transmission device 12a comprises a time of a minimum 68a of the rectified grid voltage 64a, in the form of an AC voltage, of the supply grid 26a. Particularly preferably, the time of the transmission pauses 62a of the voltage signal 60a of the second energy transmission device 12a is synchronized with the first energy transmission device 12a, wherein in particular the time of the transmission pauses 62a of the voltage signal 58a of the first energy transmission device 12a corresponds to the time of the transmission pauses 62a of the voltage signal 60a of the second energy transmission device 12a. Synchronizing the times of the transmission pauses 62a preferably at least substantially prevents mutual influencing of the voltage signals 58a, 60a during the transmission pauses 62a. The duration 70a of the transmission pauses 62a in particular corresponds to a value from a range of values of in particular 0.1 ms to 3 ms, preferably 0.5 ms to 2 ms and particularly preferably 1 ms to 1.5 ms, particularly advantageously preferably of 1.2 ms. It is conceivable for the duration 70a of the transmission pauses 62a of the first energy transmission device 12a and the second energy transmission device 12a to be equalized in the synchronization, in particular by way of control and/or regulation units 36a of the first energy transmission device 12a and the second energy transmission device 12a.

[0045] FIGS. 5 to 7 show a further exemplary embodiment of the invention. The following description and the drawings are restricted essentially to the differences between the exemplary embodiments, wherein reference may basically also be made to the drawings and/or the description of the other exemplary embodiments, in particular of FIGS. 1 to 4, with regard to components with the same designation. In order to distinguish between the exemplary embodiments, the letter a has been placed after the reference signs in the exemplary embodiment in FIGS. 1 to 4. In the exemplary embodiments of FIGS. 5 to 7, the letter a has been replaced by the letter b.

[0046] FIG. 5 shows an exemplary sequence of an alternative configuration of a method 100b for wirelessly transmitting electrical energy to an energy reception device 16b by way of an energy transmission device 12b. In at least one method step 102b of the method 100b, electrical energy is wirelessly transmitted to the energy reception device 16b by way of at least one oscillating circuit 28b of the energy transmission device 12b using at least one voltage signal 60b. In at least one further method step 104b of the method 100b, in particular at regular time intervals, transmission pauses 62b of the voltage signal 60b take place in order to detect foreign bodies and/or to allow the energy transmission device 12b to communicate with the energy reception device 16b and/or with an external unit 40b. In at least one further method step 106b of the method 100b, at least one time of the transmission pauses 62b of the voltage signal 60b is temporally ascertained on the basis of at least one external reference signal 72b, which is in particular independent of the energy reception device 16b, by way of at least one control and/or regulation unit 36b of the energy transmission device 12b (cf. FIG. 6). The method 100b illustrated in FIG. 5 has an at least substantially analogous design to the method 100a described in the description of FIGS. 1 to 4, meaning that reference may be made at least substantially to the description of FIGS. 1 to 4 with regard to a design of the method 100b illustrated in FIG. 5. In contrast to the method 100a described in the description of FIGS. 1 to 4, in the method 100b illustrated in FIG. 5, the external reference signal 72b is preferably in the form of an interference signal that is overlaid on the voltage signal 60b. Particularly preferably, a system 10b and the energy transmission device 12b of the system 10b for performing the method 100b are of an analogous and/or identical form to the system 10a and energy transmission device 12a described in FIGS. 1 to 4. By way of example, the interference signal is in the form of a magnetic alternating field that induces an electric current in the oscillating circuit 28b, in particular when it passes through a transmission coil 18b of the energy transmission device 12b. It is in particular conceivable for the interference signal to be in the form of a signal from another transmission coil of another energy transmission device, wherein electrical energy is in particular transmitted to another energy reception device. A current is preferably induced in the oscillating circuit 28b by the interference signal. Preferably, a signal characteristic variable, in the form of an amplitude, of the voltage signal 60b is changed by the interference signal, in particular during the transmission pauses 62b. Particularly preferably, the interference signal changes a quality characteristic value of the oscillating circuit 28b and/or a transmission system 48b consisting of oscillating circuit 28b and energy reception unit 16b.

[0047] In at least one further method step 114b of the method 100b, the external reference signal 72b is detected by way of the control and/or regulation unit 36b during the transmission pauses 62b of the voltage signal 60b. The external reference signal 72b in the form of an interference signal is preferably detected continuously or periodically by way of the control and/or regulation unit 36b during the transmission pauses 62b of the voltage signal 60b and stored in at least one storage unit 38b of the control and/or regulation unit 36b. The external reference signal 72b in the form of an interference signal is preferably detected by evaluating the voltage signal 60b by way of the control and/or regulation unit 36b in terms of changes in the signal characteristic variable or the quality characteristic value of the voltage signal 60b, in particular during the transmission pauses 62b. By way of example, the control and/or regulation unit 36b compares signal characteristic variables or quality characteristic values of the voltage signal 60b in successive transmission pauses 62b in order to identify changes in the voltage signal 60b that are brought about by the interference signal overlaid on the voltage signal 60b.

[0048] In at least one further method step 116b of the method 100b, the external reference signal 72b is detected by way of the control and/or regulation unit 36b through a comparison of the voltage signal 60b with at least one reference pattern. The reference pattern is preferably detected in at least one method step of the method 100b, this in particular not being shown in FIG. 5, in particular independently of an interference signal, and stored in the control and/or regulation unit 36b, in particular the storage unit 38b. The reference pattern is preferably in the form of a voltage signal during a transmission pause 62b. It is conceivable for a multiplicity of reference patterns to be stored in the control and/or regulation unit 36b, wherein each reference pattern is assigned at least one state characteristic variable, in particular an electrical energy, a voltage or the like, of the oscillating circuit 28b and/or a duration 70b of the transmission pauses 62b. The reference pattern for the comparison with the voltage signal is preferably selected from the multiplicity of stored reference patterns by way of the control and/or regulation unit 36b on the basis of the duration 70b of the transmission pauses 62b of the voltage signal 60b and/or of the state characteristic variable of the oscillating circuit 28b generating the voltage signal 60b, wherein the duration 70b of the transmission pauses 62b and the state characteristic variable of the oscillating circuit 28b in particular at least substantially match the duration 70b, assigned to the reference pattern, of the transmission pauses 62b and/or the state characteristic variable, assigned to the reference pattern, of the oscillating circuit 28b. If the voltage signal 60b differs from the reference pattern during the transmission pauses 62b, an interference signal is detected, wherein a deviation of the voltage signal 60b from the reference signal is in particular ascertained.

[0049] In at least one further method step 118b of the method 100b, the external reference signal 72b is detected by way of the control and/or regulation unit 36b through a comparison of quality characteristic values, determined and/or calculated by way of the control and/or regulation unit 36b, of the oscillating circuit 28b during at least two in particular successive transmission pauses 62b of the voltage signal 60b. The quality characteristic values of the oscillating circuit 28b are preferably compared with one another by way of the control and/or regulation unit 36b in order to ascertain the external reference signal 72b, wherein an interference signal is detected in particular in the event of a temporal change in the quality characteristic value. Particularly preferably, the external reference signal 72b is detected in at least one calibration mode of the energy transmission device 12b, wherein in particular a gap 24b between energy transmission device 12b and energy reception device 16b is free of foreign bodies. It is conceivable for the calibration mode to be activated automatically when the energy transmission device 12b is switched on and/or to be able to be activated by a user of the energy transmission device 12b, wherein a query is preferably made, by way of the control and/or regulation unit 36b and/or by way of an input and/or output unit of the energy transmission device 12b, as to whether the gap 24b is free of foreign bodies. As an alternative or in addition, it is conceivable for a temporal profile of the external reference signal 72b to be detected by way of a quality characteristic value, detected by way of the control and/or regulation unit 36b and/or by way of a sensor unit of the energy transmission device 12b, this in particular not being shown in the figures, of the oscillating circuit 28b and/or of the transmission system 48b consisting of oscillating circuit 28b and energy reception device 16b. The transmission pauses 62b are preferably time-shifted in increments in order to detect the temporal profile of the external reference signal 72b and the quality characteristic value is plotted over the time shift of the transmission pauses 62b. During the processing of the temporal profile of the external reference signal 72b in order to ascertain the time of the transmission pauses 62b of the voltage signal 60b, at least one time of a maximum of the temporal profile of the quality characteristic value is preferably determined by way of the control and/or regulation unit 36b using the quality characteristic value. The voltage signal 60b is in particular adapted by way of the control and/or regulation unit 36b such that the transmission pauses 62b temporally comprise the time of the maximum of the temporal profile of the quality characteristic value.

[0050] In at least one further method step 120b of the method 100b, the voltage signal 60b is adapted, in particular time-shifted, by way of the control and/or regulation unit 36b, in particular using at least one algorithm, such that the time of the transmission pauses 62b of the voltage signal 60b corresponds at least substantially to a time of a minimum of the interference signal. The algorithm is preferably executed at least by way of the control and/or regulation unit 36b. The transmission pauses 62b are preferably time-shifted in increments by way of the algorithm and a characteristic variable of the voltage signal 60b, in the form of a deviation of the voltage signal 60b from the reference signal, is detected, in particular by the control and/or regulation unit 36b. Preferably, following a time shift of the transmission pauses 60b, which time shift corresponds to at least one period duration of the voltage signal 60b, the characteristic variable of the voltage signal 60b is plotted following the time shift of the transmission pauses 62b by way of the algorithm, wherein at least one minimum of the characteristic variable of the voltage signal 60b is in particular ascertained by way of the control and/or regulation unit 36b. The voltage signal 60b is preferably adapted by way of the control and/or regulation unit 36b such that the transmission pauses 62b comprise a time of the minimum of the characteristic variable of the voltage signal 60b.

[0051] In at least one further method step 122b of the method 100b, the ascertained time of the transmission pauses 62b of the voltage signal 60b is synchronized with at least one external unit 40b, in particular another energy transmission device 12b, by way of at least one communication unit 14b of the energy transmission device 12b. Preferably, in at least one method step of the method 100b, in particular method step 122b, in particular after the minimum of the characteristic variable of the voltage signal 60b has been determined by the algorithm, at least one synchronization signal is output to at least one further energy transmission device 12b in the vicinity of the energy transmission device 12b, preferably by way of a communication unit 14b of the energy transmission device 12b. The communication unit 14b is preferably designed to convey the ascertained time of the transmission pauses 62b to the further energy transmission device 12b using the synchronization signal and/or to signal an end of a run-through of the algorithm of the energy transmission device 12b. As an alternative or in addition, it is conceivable for the ascertained time of the transmission pauses 62b of the voltage signal 60b to be transmitted to the external unit 40b or the further energy transmission device 12b by way of the communication unit 14b. In particular if the communication unit 14b exchanges electronic data 44b with the further energy transmission device 12b, it is conceivable for transmission pauses 62b of the further energy transmission device 12b and of the energy transmission device 12b to be synchronized by the communication unit 14b, in particular during transmission pauses 62b.

[0052] In particular in a use of the method 100b with the system 10b consisting of multiple energy transmission devices 12b, the transmission pauses 62b of the voltage signals 60b of the energy transmission devices 12b are preferably each synchronized by executing the algorithm when each of the energy transmission devices 12b is put into service, wherein the interference signal is in particular preferably in the form of magnetic alternating fields of transmission coils 18b of energy transmission devices 12b that are already in operation at the time of putting into service. The algorithm is in particular designed to synchronize a time of the transmission pauses 62b of the voltage signal 60b of the energy transmission device 12b to be put into operation with other energy transmission devices 12b of the system 10b that have already been put into operation, wherein in particular the other energy transmission devices 12b are already in each case synchronized with one another by the algorithm.

[0053] FIG. 6 shows a schematic illustration of a temporal profile of two voltage signals 60b, 74b from two energy transmission devices 12b of different design. The voltage signals 60b, 74b, in particular the frequency of the voltage signals 60b, 74b, are shown schematically in FIG. 6 and have an abstract relationship in relation to transmission pauses 62b, 76b of the voltage signals 60b, 74b and to grid voltages 66b, in the form of DC voltages, of the supply grids 26b of the energy transmission devices 12b in order to clarify the illustration. A time is in particular plotted on the abscissas shown in FIG. 6. A signal strength is preferably plotted on the ordinates shown in FIG. 6. The repetition rate of the transmission pauses 62b, 76b preferably corresponds to a value from a range of values of in particular 40 Hz to 200 Hz, preferably 60 Hz to 150 Hz and particularly preferably 100 Hz to 120 Hz. The voltage signals 60b, 74b preferably have a frequency that corresponds in particular to at least 1 kHz, preferably at least 10 kHz and particularly preferably at least 80 kHz. A first energy transmission device 12b is operated with the grid voltage 66b, in the form of a DC voltage, of the supply grid 26b. A second energy transmission device 12b is operated with the grid voltage 66b in the form of a DC voltage. The time of the transmission pauses 62b of the voltage signal 60b from the first energy transmission device 12b differs from the time of the transmission pauses 76b of the voltage signal 74b from the second energy transmission device 12b. During the transmission pauses 62b of the first energy transmission device 12b, the voltage signal 60b of the first energy transmission device 12b is influenced by a magnetic alternating field generated by the voltage signal 74b of the second energy transmission device 12b by way of the transmission coil 18b, wherein in particular an amplitude of the voltage signal 60b of the first energy transmission device 12b is changed. Changing the amplitude of the voltage signal 60b of the first energy transmission device 12b during the transmission pauses 60b in particular disrupts, interrupts and/or influences the identification of foreign bodies and/or the transmission of data by the first energy transmission device 12b. The change in the amplitude of the voltage signal 60b of the first energy transmission device 12b is the external reference signal 72b in the form of an interference signal, which is used, in particular in the method 100b, to ascertain the time of the transmission pauses 62b of the voltage signal 60b.

[0054] FIG. 7 shows a schematic illustration of a temporal profile of two voltage signals 60b, 74b from two energy transmission devices 12b of different design. The two energy transmission devices 12b are in particular of identical form to the two energy transmission devices 12b whose voltage signals 60b, 74b are shown in FIG. 6. A time is in particular plotted on the abscissas shown in FIG. 7. A signal strength is preferably plotted on the ordinates shown in FIG. 7. In the temporal profile of the two voltage signals 60b, 74b shown in FIG. 7, the transmission pauses 62b, 76b of the two voltage signals 60b, 74b are synchronized, in particular by way of the external reference signal 72b, preferably by way of the method 100b, wherein in particular the time of the transmission pauses 62b of the voltage signal 60b of the first energy transmission device 12b corresponds to the time of the transmission pauses 76b of the voltage signal 74b of the second energy transmission device 12b. Synchronizing the times of the transmission pauses 62b, 76b preferably at least substantially prevents mutual influencing of the voltage signals 60b, 74b during the transmission pauses 62b, 76b. A duration 70b of the transmission pauses 62b, 76b in particular corresponds to a value from a range of values of in particular 0.1 ms to ms, preferably 0.5 ms to 2 ms and particularly preferably 1 ms to 1.5 ms, particularly advantageously of 1.2 ms. It is conceivable for the duration 70b of the transmission pauses 62b, 76b of the first energy transmission device 12b and of the second energy transmission device 12b to be equalized in the synchronization, in particular by way of control and/or regulation units 36b of the first energy transmission device 12b and the second energy transmission device 12b. The voltage signals 60b, 74b shown in FIG. 7, following the synchronization, are in particular at least substantially in a form free from external reference signals in the form of an interference signal, wherein in particular mutual influencing of the voltage signals 60b, 74b during the transmission pauses 62b, 76b is at least substantially prevented, in particular by a reduced amplitude of the voltage signals 60b, 74b during the transmission pauses 62b, 76b in comparison with between the transmission pauses 62b, 76b.