System for inductive energy transfer

Abstract

The invention relates to a system (1) for inductive energy transfer, comprising at least one stationary inductive charging device (2, 2a) and at least one mobile inductive charging device (2, 2b), which, in charging operation, interact with the mobile inductive charging device for inductive energy transfer. The positioning device (4) generates at least two transmission signals (5, 5a, 5b) having different frequencies in one of the inductive charging devices (2, 2a), which are received on the other inductive charging device (2, 2a) as superimposed reception signals (11). The positioning device (4) determines an associated amplitude for the respective received transmission signal (5, 5a, 5b) from the reception signals. This results in the determination of the relative position in a simple manner with reduced hardware overhead and reduced cost. The invention further relates to a computer program product for determining amplitudes.

Description

Technical Field

[0001] The invention relates to a system for inductive energy transmission, comprising at least one stationary inductive charging device and at least one mobile inductive charging device, wherein a positioning device determines the relative positions of the inductive charging devices that interact inductively with each other for the inductive energy transmission. The invention also relates to a computer program product for the system. Background Art

[0002] Typically, for inductive energy transmission, a stationary inductive charging device and a mobile inductive charging device work together inductively in a system. The mobile inductive charging device is typically arranged in an associated mobile application, for example in a motor vehicle, in order to enable inductive energy transmission between the mobile application and the stationary inductive charging device. For energy transmission, the corresponding inductive charging device has energy coils, wherein the energy coils are coupled to each other during charging operation for inductive energy transmission. For this purpose, the energy coils need to be positioned accordingly relative to each other. With more accurate positioning of the energy coils relative to each other, the efficiency of energy transmission can be increased. Summary of the invention

[0003] The present invention is based on the object of specifying an improved or at least different embodiment for a system of the type mentioned in the introduction and for a computer program product for the system.

[0004] This object is achieved according to the invention by the subject matter of the independent claim. Advantageous embodiments are the subject matter of the dependent claims.

[0005] The invention is therefore based on the following basic idea: In a system for inductive energy transmission, signals of different frequencies are used to determine the relative position of the associated energy coils, wherein a superposition of these signals is received and an associated amplitude is determined from the superposition for the respective received signal in order to determine the relative position of the energy coils relative to one another. The use of at least two signals with respectively associated frequencies allows a more accurate determination of the relative position. At the same time, processing the superposition of the signals for the determination of the amplitudes results in a simple implementation of the receiver of the signals, wherein a reliable and accurate determination of the amplitude of the signal, which is relevant to the determination of the relative position, is nevertheless produced.

[0006] According to the inventive concept, the system has at least one fixed inductive charging device and at least one mobile inductive charging device. The corresponding mobile inductive charging device is arranged in an assigned mobile application, in particular in a motor vehicle. The corresponding inductive charging device has a coil for inductive energy transmission, which is also referred to as an energy coil hereinafter. That is to say, the corresponding fixed inductive charging device has a fixed energy coil, and the corresponding mobile inductive charging device has a mobile energy coil. In charging operation, the corresponding fixed inductive charging device cooperates with one of the at least one mobile inductive charging devices to inductively transmit energy with the aid of the energy coil. The positioning device of the system is used to identify the relative positions of the energy coils assigned to each other in charging operation. The positioning device has a transmitting device in one of the inductive charging devices assigned to the charging operation, and a receiving device in the other inductive charging device. The transmitting device has at least two transmitters.

[0007] The corresponding transmitter outputs a signal during operation, which has an assigned, pre-set and therefore known frequency, wherein the frequencies of the transmitters are different. That is to say, the transmitters simultaneously output transmission signals with the assigned pre-set frequencies during operation. The receiving device has a receiver for receiving the transmission signal. The receiver is configured in such a way that the receiver outputs the superposition of all received transmission signals as a time-dependent signal. This signal is also referred to as a received signal hereinafter. In addition, the positioning device is configured in such a way that the positioning device obtains the assigned amplitude for the corresponding received transmission signal from the received signal. In addition, the positioning device is configured in such a way that the positioning device generates position information from the obtained amplitude, which represents the relative position of the energy coils relative to each other.

[0008] Advantageously, the position information is provided to an auxiliary device, in particular a driving assistance device, in order to enable a movement of the mobile inductive charging device, in particular a mobile application, relative to the stationary inductive charging device, the relative movement leading to an optimization of the inductive energy transmission and thus to an optimal positioning of the energy coils relative to one another. This can be achieved, for example, via a human-machine interface (also known by the English abbreviation "HMI") in order to transmit a corresponding suggestion to a leader of the mobile application, in particular a driver of the vehicle. Alternatively or additionally, the auxiliary device can at least partially automatically move the mobile application, in particular at least partially automatically drive the mobile application, taking into account the position information.

[0009] In charging operation, the inductively cooperating power coils are arranged opposite each other and spaced apart from each other in a direction, which is referred to below as the first direction. In a motor vehicle as a mobile application, this first direction corresponds to the Z direction of the motor vehicle.

[0010] The system may have a single stationary inductive charging device.

[0011] The system can also have two or more stationary inductive charging devices. For example, the system can have an associated stationary inductive charging device for at least two different parking spaces in a parking lot (for example in a parking garage).

[0012] The system may have a single mobile inductive charging device.

[0013] The system can also have two or more mobile inductive charging devices. In this case, the respective mobile inductive charging device is advantageously a component of an associated mobile application. This means, for example, that the system can have at least two mobile inductive charging devices, wherein the respective mobile inductive charging device is a component of an associated motor vehicle.

[0014] The corresponding stationary inductive charging device can inductively cooperate with the corresponding at least one mobile inductive charging device for inductively transmitting energy. That is, in charging operation, the corresponding stationary inductive charging device inductively cooperates with one of the at least one mobile inductive charging device for inductively transmitting energy.

[0015] In charging operation, one power coil is used as a primary coil and the other power coil is used as a secondary coil. That is, bidirectional inductive energy transmission is also possible.

[0016] Advantageously, the position information is used for the purpose of enabling, in particular with the aid of an auxiliary device, an improved and simplified positioning of the energy coils relative to one another transversely to the first direction. This means that with the aid of the position information, an improved and simplified positioning of the energy coils relative to one another in a second direction transversely to the first direction and in a third direction transversely to the first direction and transversely to the second direction is enabled. In a motor vehicle as a mobile application, the second direction and the third direction correspond to the X direction and the Y direction of the motor vehicle.

[0017] As mentioned above, the received signal corresponds to the superposition of all received transmitted signals. Here, the received signal is time-dependent, ie, can change in a time-dependent manner.

[0018] The locating device can determine the amplitude associated with the received signal from the received signal in any desired manner, ie in particular by means of any desired method / concept.

[0019] In a preferred specific embodiment, the locating device is designed in such a way that it demodulates the received signal by means of IQ demodulation and thus determines from the received signal an associated amplitude for the respective received transmitted signal.

[0020] In IQ demodulation, at least one so-called I value and at least one so-called Q value are extracted from the received signal for the corresponding frequency and thus for the corresponding transmitted signal. In this case, for the amplitude A of the corresponding transmitted signal:

[0021]

[0022] Alternatively or additionally, the locating device can be designed in such a way that it determines the associated amplitude for the corresponding received transmit signal from the received signal by means of a Fourier transform. Preferably, this is done by means of a fast Fourier transform (also known by the English name "Fast-Fourier-Transformation" and the abbreviation "FFT").

[0023] Alternatively or additionally, the locating device can be designed such that it determines the associated amplitude for the respective received transmit signal from the received signal using a finite impulse response filter. Finite impulse response filters are also known by the English name “Finite Impulse Response Filter” and the abbreviation “FIR”.

[0024] When using a finite impulse response filter, segment correlation and / or convolution is preferably used. That is, the locating device can be designed in such a way that it determines the associated amplitude for the corresponding received transmit signal from the received signal by means of segment correlation and / or convolution.

[0025] Advantageously, in the case of a finite impulse response filter, a rectangular window is used which corresponds to the spectrum of the sought frequency range, in particular the IQ demodulation. The locating device is designed accordingly.

[0026] Preferably, in the case of a finite impulse response filter, a cosine roll-off window is applied. The positioning device is configured accordingly. This has the advantage that the side lobes in the spectrum are attenuated, in particular during IQ demodulation, and thus a significant reduction in interference sensitivity is achieved.

[0027] In the following, IQ demodulation is discussed primarily. However, it is clear that the explanations and in particular the parts described can be applied accordingly to other implementations for ascertaining the amplitude.

[0028] Advantageously, the receiving device samples the received signal at a sampling rate that matches the frequency of the transmitted signal. That is to say, advantageously, the receiving device is configured so that the receiving device sequentially samples the received signal at a sampling rate that corresponds to an integer multiple of the frequency of the corresponding transmitted signal. Here, the amplitude assigned to the corresponding transmitted signal is determined with the aid of the sampled value. That is, the received signal is sampled at an integer multiple of the frequency corresponding to one of the transmitted signals, and the amplitude assigned to the transmitted signal is determined based on the value thus determined. Next, the received signal is sampled at an integer multiple of the frequency of another transmitted signal in the transmitted signal, and the amplitude assigned to the transmitted signal is determined based on the value thus determined, and so on. Therefore, accurate determination of the I value and the Q value is achieved, and therefore accurate determination of the amplitude is achieved.

[0029] In a preferred embodiment, the receiving device is configured in such a way that it samples the received signal in sequence at a sampling rate corresponding to four times the frequency of the corresponding transmitted signal. That is, the sampling rate for the corresponding transmitted signal corresponds to four times the frequency of the transmitted signal. Therefore, in IQ demodulation, two I values ​​and two Q values ​​are determined, for example I at 0°, Q at 90°, -I at 180° and -Q at 270°. In particular, in this way, it is not necessary to know the phase of the received signal. This leads to a simple and resource-saving determination of the amplitude and therefore to a simple and resource-saving determination of the position information.

[0030] Preferably, a plurality of I and Q values, in particular several hundred I and Q values, are determined for the corresponding sampling rate and therefore for the corresponding transmission signal, and these I and Q values ​​are averaged. In this case, the amplitude is determined by means of the averaging. The locating device is designed accordingly. In addition to the simple and resource-saving determination of the amplitude, this leads to an increase in the resolution accuracy and therefore to a reliable determination of the position information.

[0031] It is also conceivable to sample the received signal with so-called "undersampling". In this case, for a given frequency, the spacing t between I, Q, -I and -Q is still a multiple of the frequency, in particular four times. However, the time interval between two I values ​​or Q values ​​can correspond to a multiple of the period duration of the frequency. Likewise, I, Q, -I and -Q can be sampled in a staggered manner. For example, for the spacing t between the sampling time points for I and Q, the following can apply: t_Q_n=t_I_n+360°+90°.

[0032] In a preferred embodiment, the receiving device has an analog-to-digital converter (also known by the English abbreviation "ADC") and a microcontroller, in particular a digital signal processor (also known by the English abbreviation "DSP"), for sampling the received signal and / or for determining the corresponding amplitude, the analog-to-digital converter being connected downstream of the receiver, and the microcontroller being connected to the analog-to-digital converter in a data transmission manner. In this case, the microcontroller, in particular the digital signal processor, successively adjusts the analog-to-digital converter to the sampling rate. In other words, the corresponding sampling rate is the clock of the analog-to-digital converter, which is successively adjusted by the microcontroller, in particular the digital signal processor, for the corresponding transmission signal. The analog-to-digital converter transmits the sampled values ​​(i.e., I values ​​and Q values) to the microcontroller, in particular the digital signal processor, wherein the microcontroller, in particular the digital signal processor, successively determines the amplitude associated with the transmission signal from the sampled values.

[0033] The locating device is designed accordingly. The following knowledge is used here: the amplitude A for a certain frequency always corresponds to the square root of the sum of the squares of the I value and the Q value, independently of the phase, ie

[0034] .

[0035] As described above, the phase considerations are omitted and therefore in particular the use of mixers is also omitted. The amplitude can therefore be determined with a sufficiently high resolution accuracy using less hardware and therefore also more cost-effectively. This results in a precise determination of the amplitude and therefore of the position information at reduced costs.

[0036] The following embodiment is considered to be preferred: the receiving device is configured in such a way that it determines an offset of the received signal from two values ​​of at least one of the sampling rates (advantageously the respective sampling rate) offset by 180° and takes this offset into account when determining the amplitude. In this case, it is necessary to take this offset (also known by the English name "Offset") into account in such a way that the received signal is within the operating parameters of the analog-to-digital converter. In the above-described determination of, for example, Q and -Q or I and -I, this offset is determined directly and simultaneously in a simplified manner.

[0037] Advantageously, the received signal is conditioned before being passed to the analog-to-digital converter. In particular, this may include the above-mentioned consideration of the offset. Likewise, the conditioning may include an amplification of the received signal.

[0038] Alternatively or additionally, the receiving device can advantageously alternatively have at least one mixer, wherein the at least one mixer mixes the received signals for the corresponding frequencies in a manner offset by 90° in order to provide corresponding I and Q values.

[0039] In a preferred embodiment, the receiving device has two mixers and an analog-to-digital converter and a local oscillator and a microcontroller, wherein the mixer is connected downstream of the receiver, the analog-to-digital converter is connected downstream of the mixer, and the local oscillator is connected to the mixer. The microcontroller is connected to the analog-to-digital converter and to the local oscillator. Here, the received signal is transmitted to the mixer. The conditioning of the received signal can be performed in advance. The microcontroller sequentially adjusts the frequency assigned to the corresponding transmission signal on the mixer with the help of the local oscillator so that the mixer mixes the received signal in a manner offset by 90° relative to each other and provides it to the analog-to-digital converter. The analog-to-digital converter provides the converted signal to the microcontroller, wherein the microcontroller sequentially obtains the amplitude assigned to the transmission signal from the converted signal. The receiving device is configured accordingly.

[0040] Advantageously, a low-pass filter is arranged between the respective mixer and the analog-to-digital converter.

[0041] Alternatively, it is conceivable to use a dedicated switching group consisting of a mixer and an analog-to-digital converter (possibly together with a low-pass filter) for each frequency. The amplitudes can thus be ascertained simultaneously.

[0042] In principle, the receiver can be designed in any desired manner.

[0043] Advantageously, the receiver has at least one coil for receiving the transmitted signal.

[0044] Preferably, the receiver has two windings wound offset from each other, which are also referred to below as receiving coils, which receive the transmission signal and output the reception signal. In particular, the receiving coils are wound transversely to each other, ie offset by 90° relative to each other.

[0045] Preferably, the receiving device has a single such receiver, which results in a compact design and cost-effective production of the receiving device.

[0046] In principle, a corresponding transmitter can generate an associated transmit signal having any arbitrary, associated and predefined frequency.

[0047] Advantageously, the transmitter generates a respectively assigned transmit signal having a frequency in the kilohertz range.

[0048] Preferably, the specified frequency of the corresponding transmitter is between 110 kHz and 148.5 kHz.

[0049] Advantageously, the frequencies of the transmitters are spaced apart from each other by at least 0.5 kHz.

[0050] Advantageously, the transmitting device has at least two transmitters for determining the relative position of the power coils relative to one another in the region near the stationary power coil, the transmitters being spaced apart from one another transversely to the first direction, and the transmitters being also referred to below as near-field transmitters. Thus, during operation, the respective near-field transmitter generates an associated transmission signal having an associated predetermined frequency. In this case, in the case of a corresponding positioning relative to the near-field transmitter, the received signal comprises a superposition of the at least two transmission signals.

[0051] Advantageously, the region close to the stationary power coil is a region which is at a distance of at most 0.5 m from the stationary inductive charging device, extending transversely to the first direction.

[0052] Preferably, the respective near-field transmitter generates a magnetic field having a main axis along the first direction as the transmission signal.

[0053] Advantageously, the transmitter device is a transmitter for determining the relative position of the power coils relative to one another in a region remote from the stationary power coil, which transmitter is also referred to below as a far-field transmitter. Thus, during operation, the far-field transmitter generates an associated transmission signal having an associated predetermined frequency.

[0054] Advantageously, the region remote from the stationary power coil is a region which is at a distance from the stationary inductive charging device of more than 0.5 m, in particular more than 1.5 m, extending transversely to the first direction.

[0055] Preferably, during operation, the far-field transmitter generates a magnetic field having a main axis which is inclined or transverse to the first direction as a transmission signal.

[0056] In principle, the transmitting device can be arranged in the mobile inductive charging device, and the receiving device can be arranged in the stationary inductive charging device. In this case, the corresponding mobile inductive charging device expediently has such a transmitting device, and the corresponding stationary inductive charging device has such a receiving device.

[0057] In a preferred embodiment, the transmitting device is arranged in the stationary inductive charging device and the receiving device is arranged in the mobile inductive charging device. As a result, less delay occurs when determining the position information and in particular in the auxiliary device.

[0058] In this case, the corresponding stationary inductive charging device expediently has such a transmitting device and the corresponding mobile inductive charging device has such a receiving device.

[0059] If the system has two or more transmitting devices, in particular two or more stationary inductive charging devices, each having a transmitting device, the far-field transmitters of adjacent transmitting devices preferably have different preset frequencies.

[0060] Preferably, a computer program product is used to determine the amplitude and generate the position information.

[0061] The computer program product comprises instructions which, when executed by a locating device, cause the locating device to ascertain the amplitude and generate position information.

[0062] The computer program product is stored in a non-volatile memory. Advantageously, the computer program product is stored at least partially, in particular completely, in a locating device, in particular in a receiving device.

[0063] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0064] It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively stated combination but also in other combinations or alone without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar components or components having the same function.

[0066] The accompanying drawings schematically show:

[0067] Figure 1 shows a greatly simplified circuit diagram of a system for inductive energy transmission in charging operation of two inductive charging devices,

[0068] Figure 2 shows a simplified top view of an inductive charging device having a transmitting device of a locating device of a system,

[0069] Figure 3 a graph showing a transmission signal of a transmitter of a transmission device,

[0070] Figure 4 A top view showing a receiver of a receiving device of a positioning device,

[0071] Figure 5 shows the received signal of the receiver,

[0072] Figure 6 A circuit diagram showing a receiver device,

[0073] Figure 7 A circuit diagram of a receiver device in another exemplary embodiment is shown. DETAILED DESCRIPTION

[0074] exist Figures 1 to 7 The system 1 shown by way of example in FIG. 1 is used for inductive energy transmission. Figure 1 For this purpose, the system 1 has at least two inductive charging devices 2, namely at least one stationary inductive charging device 2, 2a and at least one mobile inductive charging device 2, 2b. Figure 1 In the illustrated charging operation, the respective stationary inductive charging device 2, 2a can inductively cooperate with one of the at least one mobile inductive charging devices 2, 2b for inductive energy transfer. Thus, in the charging operation, the respective stationary inductive charging device 2 can be a charging point for system 1. For inductive energy transfer, the respective inductive charging device 2 (e.g., in particular in the Figure 1 ) has a coil 3, which is also referred to as power coil 3 in the following text. Therefore, the corresponding stationary inductive charging device 2, 2a has a stationary power coil 3, 3a (see also Figure 2 ), and the corresponding mobile inductive charging device 2, 2b has a mobile power coil 3, 3b. In charging operation, one of the power coils 3 is used as a primary coil, which generates an alternating magnetic field, which induces a voltage for energy transmission in the other power coil 3 used as a secondary coil. Figure 1 As shown, in charging operation, the inductive charging devices 2, in particular the energy coils 3 of the inductive charging devices 2, which act together for inductive energy transmission, are arranged spaced apart from each other and opposite to each other in a direction R1, which is also referred to as the first direction R1 below. The inductive charging device 2 and its energy coils 3 are also referred to as "assigned" below. The corresponding mobile inductive charging devices 2, 2b are arranged in the assigned mobile application 100. In the illustrated embodiment, the application 100 is a motor vehicle 101. Here, the first direction R1 extends along, in particular parallel to, the Z direction of the motor vehicle 101. That is, the first direction R1 corresponds in particular to the height direction. In addition, in charging operation, in order to enable charging operation and achieve high efficiency in charging operation, the assigned energy coils 3 are positioned relative to each other transversely to the first direction R1, that is, in the second direction R2 extending transversely to the first direction R1 and in the third direction R3 extending transversely to the first direction R1 and transversely to the second direction R2. In this positioning, the assigned energy coils 3 preferably overlap at least partially in the second direction R2 and in the third direction R3. In the illustrated embodiment, the second direction R2 is the driving direction of the mobile application 100 or the motor vehicle 101, that is, the X direction of the motor vehicle 101. Figure 1As shown, energy can be transmitted in an inductive manner to mobile inductive charging device 2, 2b in order to charge battery 102 of mobile application 100. For this purpose, a rectifier 26 can be provided between mobile power coil 3, 3b and battery 102, which converts the voltage induced in mobile power coil 3, 3b into a rectified voltage. In the embodiment shown, purely by way of example, rectifier 26 is a component of mobile inductive charging device 2, 2b. Inductive energy transmission can also be carried out from mobile inductive charging device 2, 2b to stationary inductive charging device 2, 2a, i.e., in principle, it can also be carried out bidirectionally.

[0075] The positioning device 4 of the system 1 is used to identify the relative position of the associated power coil 3 and thus the inductive charging device 2 relative to each other during charging operation. This can be used within the framework of driver assistance in order to position the mobile application 100, in particular the motor vehicle 101, accordingly relative to the stationary inductive charging device 2, 2a. For this purpose, the positioning device 4 generates two signals 5 in one of the inductive charging devices 2 that cooperate in the charging operation, that is, in one of the associated inductive charging devices 2. The signals 5 are also referred to as transmission signals 5 below. The transmission signals 5 are received in the other inductive charging device 2. For this purpose, the positioning device 4 has a transmission device 9 in one of the inductive charging devices 2 and a receiving device 10 in the other inductive charging device 2. The transmission signal 5 is generated by means of the transmission device 9 and received by means of the receiving device 10. In the illustrated embodiment, the transmission device 9 is a component of the stationary inductive charging device 2, 2a, and the receiving device 10 is a component of the mobile inductive charging device 2, 2b. That is, the respective stationary inductive charging device 2 , 2a has such a transmitting device 9 , and the respective mobile inductive charging device 2 , 2b has such a receiving device 10 .

[0076] If you can Figure 1 and 2As known from the figure, the transmitting device 6 has an associated transmitter 6, that is, at least two transmitters 6, for generating a corresponding transmission signal 5. During operation, the corresponding transmitter 6 generates an associated transmission signal 5 and outputs the transmission signal 5, which has an associated preset frequency f, wherein the transmitter 6 simultaneously generates and outputs the respectively associated transmission signal 5. That is, during operation, the transmitter 6 simultaneously outputs a transmission signal 5, which has an associated preset frequency f, wherein the frequencies f of these transmitters 6 are different from each other. In the illustrated embodiment, a magnetic field is generated as the transmission signal 5 by means of the corresponding transmitter 6. Here, the frequency f of the corresponding transmitter 6 and thus the transmission signal 5 is between 110 kHz and 148.5 kHz. Advantageously, the frequency f is between 134.0 kHz and 137.0 kHz and is spaced 0.5 kHz apart from each other.

[0077] If you can Figure 2 As can be seen in , in the illustrated embodiment, purely by way of example, the transmitting device 5 has four transmitters 6, namely a first transmitter 6, 6a, a second transmitter 6, 6b, a third transmitter 6, 6c and a fourth transmitter 6, 6d. Figure 2 In the top view shown, transmitter 6 is arranged in the corners of an imaginary quadrilateral (not shown), wherein the quadrilateral frames power coil 3 of the associated inductive charging device 2, i.e., in the illustrated exemplary embodiment, the power coil of the associated inductive charging device 2, 2a in the top view.

[0078] Figure 3 shows a graph of a transmission signal 5 with a transmitter 6, wherein Figure 3 In the example, the time variation curve is plotted along the corresponding abscissa axis X, and the intensity is plotted along the corresponding ordinate axis Y. Figure 3 As known from the above, the first transmitter 6, 6a transmits the first transmission signal 5, 5a with the first frequency f, f1, the second transmitter 6, 6b transmits the second transmission signal 5, 5b with the second frequency f, f2, the third transmitter 6, 6c transmits the third signal 5, 5c with the third frequency f, f3, and the fourth transmitter 6, 6d transmits the fourth transmission signal 5, 5d with the fourth frequency f, f4. At least two transmitters of the transmitter 6, preferably all transmitters 6, transmit the associated transmission signal 5 simultaneously. In addition, it can be seen from Figure 3 As can be seen in FIG. 5 , the transmission signals 5 shown are output, which have the same strength but different frequencies f. For example, the first frequency f1 is 111.5 kHz, the second frequency f2 is 112.0 kHz, the third frequency f3 is 113.0 kHz, and the fourth frequency f4 is 113.5 kHz.

[0079] For example, from Figure 4As is known from the prior art, the receiving device 10 has a receiver 7 for receiving the transmission signal 5. In the exemplary embodiment shown, the receiving device 10 has a single receiver 7. Figure 4 As can be seen in FIG. 1 , in the exemplary embodiment shown, the receiver 7 has two receiving coils 8 which are wound in a manner offset by 90° relative to one another. The signal 11 received by the receiving coil 8 is Figure 5 , and corresponds to the superposition of all received transmit signals 5. The received signal 11 is also referred to as received signal 11 in the following. The received signal 11 is therefore time-dependent. Figure 4 As indicated by means of electrical connection 12, a received signal 11 can be tapped off at the receiver 7. That is, the receiver 7 outputs the received signal 11, wherein the received signal 11 is in the form of a voltage. Figure 5 In FIG. 1 , a time variation curve is plotted along the abscissa axis X, and a voltage variation curve of the received signal 11 is plotted along the ordinate axis Y. FIG.

[0080] As hereinafter and in particular according to Figure 6 and 7 As explained, the locating device 4 is configured such that it determines the associated amplitude A for the respective received transmission signal 5 from the received signal 11. The respective amplitude A represents the strength of the associated transmission signal 5 at the location of the receiver 7, i.e., the local strength of the associated transmission signal 5. Furthermore, the locating device 4 is configured such that it generates position information from the determined amplitude A, which represents the relative position of the energy coils 3 relative to one another.

[0081] The amplitude A can be determined from the received signal 11, for example, by means of a Fourier transform, preferably by means of a fast Fourier transform (also known by the English name "Fast-Fourier-Transformation" and the abbreviation "FFT"). Alternatively or additionally, the amplitude A can be determined from the received signal 11 by means of a finite impulse response filter (also known by the English name "Finite Impulse Response Filter" and the abbreviation "FIR"). Advantageously, a correlation and / or convolution of the segments is used here. The locating device 4 is configured accordingly.

[0082] In the embodiment described below, the amplitude A is determined by means of IQ stimulation. However, it should be understood that the following description can be applied to the above-mentioned method in an analogous manner.

[0083] That is, in the exemplary embodiment shown, the locating device 4 is configured such that it demodulates the received signal 11 by means of IQ demodulation and thus determines the associated amplitude A for the corresponding received transmit signal 5 from the received signal 11. The corresponding amplitude A represents the intensity of the associated transmit signal 5 at the location of the receiver 7, that is, the local intensity of the associated transmit signal 5. Furthermore, the locating device 4 is configured such that it generates position information from the determined amplitude A, which represents the relative position of the energy coils 3 relative to each other.

[0084] exist Figure 6 In the illustrated embodiment, the amplitude A of the transmission signal 5 is determined from the received signal 11 by sampling the received signal 11. Here, in order to determine the amplitude A of the corresponding transmission signal 5 from the received signal 11, the received signal 11 is sampled at a sampling rate that corresponds to an integer multiple (four times in the illustrated embodiment) of the frequency f of the transmission signal 5. That is, in order to determine the amplitude A, A1 of the first transmission signal 5, 5a, a sampling rate is selected that corresponds to four times the first frequency f, f1. That is, in order to determine the amplitude A, A2 of the second transmission signal 5, 5b, a sampling rate is selected that corresponds to four times the second frequency f, f2. That is, in order to determine the amplitude A, A3 of the third transmission signal 5, 5c, a sampling rate is selected that corresponds to four times the third frequency f, f3. Therefore, in order to determine the amplitude A, A4 of the fourth transmission signal 5, 5d, a sampling rate is selected that corresponds to four times the fourth frequency f, f4. Therefore, for a corresponding sampling rate, four sampling points at 0°, 90°, 180° and 270° are obtained with respect to the period of the frequency f. The corresponding sampling time points provide values, wherein the values ​​determined in a manner offset by 90° relative to each other correspond in magnitude to the I value or Q value of the IQ demodulation. In other words, the value at the sampling time point 0° corresponds to I, the value at the sampling time point 90° corresponds to Q, the value at the sampling time point 180° corresponds to -I, and the value at the sampling time point 270° corresponds to -Q. Therefore, the value at the sampling time point 360° corresponds again to the value I, and so on. Therefore, when the amplitude A of the transmitted signal 5 at the predetermined frequency f is known, it always corresponds to the square root of the square of the sum of I and Q of the frequency f, that is,

[0085] In the case of , the associated amplitude A can be determined in a simple and reliable manner from the received signal 11 for the corresponding transmitted signal 5 , without having to take into account any phase conditions.

[0086] That is, therefore, in the example in question, an associated amplitude A is determined for the respective transmit signal 5, that is, a total of four amplitudes A. In order to improve / increase the resolution accuracy, a plurality of I and Q values, in particular several hundred I and Q values, can be determined for the respective sampling rate and thus for the respective transmit signal 5, and these I and Q values ​​can be averaged. It is also conceivable to carry out an averaging of the values ​​of I and −I as well as Q and −Q.

[0087] exist Figure 6 In the embodiment shown, the receiving device 10 has an analog-to-digital converter 13 connected downstream of the receiver 7 and a digital signal processor 14 connected to the analog-to-digital converter 13 in a data transmission manner. The analog-to-digital converter 13 is also known by the English abbreviation "ADC", and the digital signal processor 14 is also known by the English abbreviation "DSP". During operation, the digital signal processor 14 successively adjusts the analog-to-digital converter 13 to the sampling rate. In the embodiment shown, this is achieved via a trigger source 16 (also known by the English name "Trigger Source"), which can include, for example, a PWM generator not shown. That is, the sampling rate set on the analog-to-digital converter 13 corresponds to the current clock of the analog-to-digital converter 13. The analog-to-digital converter 13 transmits the sampled values ​​to the digital signal processor 14, which are the values ​​for I, Q, -I and -Q as described above. The digital signal processor 14 determines the amplitude A assigned to the sampling rate from the sampled values. Therefore, the received signal 11 can be sampled successively with a sampling rate of the corresponding frequency f, and therefore the amplitude A associated with the corresponding transmitted signal 5 can be determined successively from the received signal 11. This means that the amplitude A associated with the transmitted signal 5 is determined successively.

[0088] like Figure 6 As shown, the analog-to-digital converter 13 and the digital signal processor 14 can be combined in a microcontroller 15, which is also referred to below as a DSP microcontroller 15. In the embodiment shown, the DSP microcontroller 15 further comprises a trigger source 16.

[0089] If you can Figure 6 As is known from the figure, a conditioning 17 of the received signal 11 is performed between the receiver 7 and the analog-to-digital converter 13, which conditioning is indicated by means of a box. The conditioning 17 includes taking into account an offset (also known by the English name "Offset") of the received signal 11 present as a voltage. For this purpose, for at least one of the sampling rates, in particular for the corresponding sampling rate, an offset is determined from two values ​​offset by 180°. This means, for example, that the offset is determined from the values ​​for I and -I or from the values ​​for Q and -Q. Likewise, the conditioning 17 can include amplifying the received signal 11. The determination of the offset can again be performed in the digital signal processor 14.

[0090] exist Figure 7 In the embodiment shown, the receiving device 10 has two mixers 18 connected downstream of the receiver 7, an analog-to-digital converter 13 connected downstream of the mixer 18, a local oscillator 19 connected to the mixer 18, and a microcontroller 20. The microcontroller 20 is connected to the analog-to-digital converter 13 and to the local oscillator 19. Here, the received signal 11 is transmitted to the mixer 18. In the embodiment shown, the received signal 11 is transmitted to the mixer 18 after conditioning 17 (for example, after signal amplification). In order to determine the amplitude A of the transmission signal 5, the microcontroller 20 adjusts the frequency f assigned to the transmission signal 5 on the mixer 18 by means of the local oscillator 19 so that the mixer 18 mixes the received signal in a manner offset by 90° relative to each other. This is also known as the so-called "I&Q method". The mixed signal is provided to the analog-to-digital converter 13. In the embodiment shown, a low-pass filter 21 is arranged between the corresponding mixer 18 and the analog-to-digital converter 13. Furthermore, the analog-to-digital converter 13 has an associated input 22 for the respective mixer 18 and thus for the respective low-pass filter 21. Thus, the I value required for IQ demodulation reaches the analog-to-digital converter 13 via one of the inputs 22, and the Q value required for IQ demodulation reaches the analog-to-digital converter 13 via the other input 22. Thus, the microcontroller 20 can determine the amplitude A of the transmission signal 5 with the set frequency f from the data provided by the analog-to-digital converter 13 according to the above rule. After determining the amplitude A of the transmission signal 5 with the set frequency f, the microcontroller 20 sets the frequency f associated with another transmission signal 5 by means of the local oscillator 19, wherein, according to the above explanation, the amplitude A of the transmission signal 5 with the frequency f now set is determined. Thus, the microcontroller 20 sequentially sets the frequency f associated with the respective transmission signal 5 on the mixer 18 by means of the local oscillator 19, and sequentially determines the correspondingly associated amplitude A.

[0091] like Figure 1 and 2 As shown, in the illustrated embodiment, the transmitters 6 are spaced apart transversely to the first direction R1. Figure 1 As shown, the transmitter 6 generates a magnetic field with a main axis along the first direction R1 as a transmission signal 5. Therefore, the transmission signal 5 propagates locally in the area of ​​the correspondingly assigned transmitter 6 transversely to the first direction R1. Therefore, these transmission signals 5 are suitable for determining the relative position of the energy coils 3 relative to each other in the area close to the transmitter 6 transversely to the first direction R1. The corresponding transmitter 6 is also referred to as a near-field transmitter 23 below. In the embodiment shown, each near-field transmitter 23 is respectively configured as a flat coil 24, which is wound parallel to the first direction R1, that is, the winding axis (not shown) of the corresponding near-field transmitter 23 extends parallel to the first direction R1.

[0092] If you can Figure 2 As known from FIG. 1 , the transmitting device 9 can have a further transmitter 6, namely a fifth transmitter 6, 6e, which generates a magnetic field as a fifth transmission signal 5, 5e, such as Figure 2 As shown, the fifth transmission signal has a main axis along the second direction R2 and thus along the X direction. Therefore, the sixth transmission signal 5, 5e of the sixth transmitter 6, 6e propagates transversely to the first direction R1 and can therefore also be received at a longer range. The sixth transmitter 6, 6e is also referred to as the far-field transmitter 27 below. In the illustrated embodiment, the far-field transmitter 27 is wound around a winding axis (not shown) extending along the second direction R2. Here, as described for the transmission signal of the near-field transmitter 23, the sixth transmission signal 5, 5e of the far-field transmitter 27 is received by the receiver 7, and the local amplitude A of the sixth transmission signal 5, 5e of the far-field transmitter 27 is determined from the received signal 11. The frequency f of the far-field transmitter can be between 145.5 kHz and 147.5 kHz. If the system 1 has two or more transmission devices 9 each having such a far-field transmitter 27, the far-field transmitter 27 has a different frequency f than the adjacent far-field transmitter 27, preferably the adjacent far-field transmitter 27 in the second direction R2.

[0093] The relative position of the energy coils 3 relative to one another and thus position information can be determined by comparing the amplitudes A using the locally determined amplitudes A of the respective transmitters 6. This position information can be made available via an interface 25 of a microcontroller 15, 20 of a mobile application 100, in particular an auxiliary device 103 of a motor vehicle 101 (see Figure 6 ) is provided, and the auxiliary device is also Figure 1 Here, the auxiliary device 103 generates navigation instructions for the mobile application 100 based on the received position information, and the navigation instructions are Figure 1 . The navigation instructions can also be generated by means of the positioning device 4 and provided to the auxiliary device 103 via the interface 24. The navigation instructions can be provided, for example, via a human-machine interface (not shown) to a leader of the mobile application 100 for guiding the mobile application 100. Likewise, the navigation instructions can be used for at least partially automated guidance of the mobile application 100, in particular for at least partially automated guidance of the motor vehicle 101. The navigation instructions serve the purpose of achieving an improved positioning of the associated power coil 3 in order to optimize the energy transmission.

[0094] The amplitude determination and the generation of the position information are preferably realized by means of a computer program product. In this case, the computer program product is preferably at least partially stored in the receiving device, in particular in the microcontroller 15, 20, in a non-volatile memory (not shown). The computer program product includes instructions which, when executed by the locating device 4 (in the illustrated embodiment by the receiving device 10), cause the locating device 4 (in the illustrated embodiment, the receiving device 10) to determine the amplitude A and generate the position information.

Claims

1. A system (1) for inductive energy transmission, comprising at least one stationary inductive charging device (2, 2a) and at least one mobile inductive charging device (2, 2b), the mobile inductive charging device being in particular a mobile inductive charging device of at least one motor vehicle (101), -in, The corresponding stationary inductive charging device (2, 2a) has a stationary power coil (3, 3a), and the corresponding mobile inductive charging device (2, 2b) has a mobile power coil (3, 3b), - wherein, during charging operation, the respective stationary inductive charging device (2, 2a) cooperates with one of the at least one mobile inductive charging device (2, 2b) in order to inductively transfer energy by means of the power coil (3), the system comprises a positioning device (4) for detecting the relative positions of the associated power coils (3) relative to one another during charging operation, wherein the locating device (4) has a transmitting device (9) in one of the inductive charging devices (2) assigned during charging operation and a receiving device (10) in the other inductive charging device (2), - wherein the transmitting device (9) has at least two transmitters (6), and the transmitters (6) respectively output a transmission signal (5) having an associated predetermined frequency simultaneously during operation, and the frequencies of the transmitters (6) are different, wherein the receiving device (10) has a receiver (7) which is designed such that it outputs a superposition of all received transmission signals (5) as a time-dependent reception signal (11), wherein the locating device (4) is designed in such a way that it determines from the received signal (11) an associated amplitude for the respective received transmitted signal (5), - wherein the locating device (4) is designed in such a way that it generates position information from the ascertained amplitudes, which represents the relative position of the energy coils (3) with respect to one another.

2. The system according to claim 1, characterized in that The locating device (4) is designed in such a way that it demodulates the received signal (11) by means of IQ demodulation and thereby determines from the received signal (11) at least one associated I value and at least one associated Q value for a corresponding received transmitted signal (5) and determines from these values ​​an associated amplitude.

3. The system according to claim 1 or 2, characterized in that: The locating device (4) is designed in such a way that it determines from the received signal (11) an associated amplitude for a corresponding received transmit signal (5) by means of a Fourier transformation, in particular a fast Fourier transformation.

4. The system according to any one of claims 1 to 3, characterized in that The localization device (4) is designed in such a way that it determines an associated amplitude for a corresponding received transmission signal (5) from the received signal (11) by means of a finite impulse response filter, in particular by means of a segment correlation and / or by means of a convolution.

5. The system according to any one of claims 1 to 4, characterized in that The receiving device (10) is designed such that it successively samples the received signal (11) at a sampling rate corresponding to an integer multiple of the frequency of the corresponding transmitted signal (5) and determines an amplitude associated with the corresponding transmitted signal (5) using the sampled values.

6. The system according to claim 5, characterized in that The receiving device (10) is designed in such a way that it successively samples the received signal (11) at a sampling rate corresponding to four times the frequency of the corresponding transmitted signal (5).

7. The system according to claim 5 or 6, characterized in that: The receiving device (10) comprises an analog-to-digital converter (13) and a digital signal processor (14) for sampling the received signal (11) and for determining the corresponding amplitude, the analog-to-digital converter being connected downstream of the receiver (7) and the digital signal processor being connected to the analog-to-digital converter (13) in a data transmission manner, wherein the receiving device (10) is configured such that - causing the digital signal processor (14) to sequentially adjust the analog-to-digital converter (13) to the sampling rate and the analog-to-digital converter (13) to transmit the sampled values ​​to the digital signal processor (14), - causing the digital signal processor (14) to successively ascertain the amplitudes assigned to the transmission signal (5) from the sampled values.

8. The system according to any one of claims 6 to 8, characterized in that in, The receiving device (10) is designed in such a way that it ascertains an offset of the received signal (11) from two values ​​of at least one of the sampling rates that are offset by 180° and takes the offset into account when ascertaining the amplitude (A).

9. The system according to any one of claims 2 to 8, characterized in that The receiving device (10) comprises two mixers (18) and an analog-to-digital converter (13) as well as a local oscillator (19) and a microcontroller (20), wherein the mixers are connected downstream of the receiver (7), the analog-to-digital converter is connected downstream of the mixers (18), the local oscillator is connected to the mixers (18), and the microcontroller is connected to the analog-to-digital converter (13) and the local oscillator (19), wherein the receiving device (10) is designed such that: - transmitting the received signal (11) to the mixer (18), - the microcontroller (20) uses the local oscillator (19) to successively set the frequencies assigned to the respective transmission signals (5) at the mixers (18) in such a way that the mixers (18) mix the reception signals (11) offset by 90° relative to one another and supply them to the analog-to-digital converter (13), The analog-to-digital converter (13) supplies the converted signal to the microcontroller (20), and the microcontroller (20) successively ascertains amplitudes associated with the transmit signal (5) from the converted signal.

10. The system according to claim 9, characterized in that A low-pass filter (21) is arranged between the respective mixer (18) and the analog-to-digital converter (13).

11. The system according to any one of claims 1 to 10, characterized in that The receiver (7) has two receiving coils (8) wound offset from one another, which receive the transmission signal (5) and output the reception signal (11).

12. The system according to any one of claims 1 to 11, characterized in that The receiving device (10) has a single receiver (7).

13. The system according to any one of claims 1 to 12, characterized in that The specified frequency of the corresponding transmitter (6) is between 110 kHz and 148.5 kHz.

14. The system according to any one of claims 1 to 13, characterized in that - in charging operation, the power coils (3) are arranged spaced apart from one another and opposite one another in a first direction (R1), The transmitting device (9) has at least two near-field transmitters (5, 23) which are spaced apart from one another transversely to the first direction (R1) and which, during operation, generate a magnetic field having a main axis along the first direction (R1) as a transmission signal (5).

15. The system according to any one of claims 1 to 14, characterized in that A corresponding stationary inductive charging device (2, 2a) has such a transmitting device (9), and a corresponding stationary inductive charging device (2, 2b) has such a receiving device (10).

16. A computer program product comprising instructions which, when executed by a positioning device (4) of a system (1) according to any one of the preceding claims, cause the positioning device (4) to determine the amplitude and generate the position information.

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