Method for operating an inductive coupling

Abstract

The invention relates to a method for operating a primary device (100) for inductive power transmission, at least a first operating mode and a second operating mode being activatable for the primary device (100); wherein, when the first operating mode is activated, a primary oscillation circuit (104) of the primary device (100) is excited such that secondary power can be transmitted to a secondary oscillation circuit (204) of the secondary device (200) coupled to the primary device (100); and wherein, when the second operating mode is activated, the primary oscillating circuit (104) is excited with a standby power and a standby operating parameter is detected; wherein the target object (300) is detected in the detection region and an output signal is generated in accordance with the detected standby operating parameter. The invention also relates to a primary device (100).

Description

Technical Field

[0001] The invention relates to a method and a system for operating an inductive coupling. Background Art

[0002] Such systems are known in which inductive power transmission is performed between a primary device (transmitter) and a secondary device (receiver) via an electromagnetic field. In this case, the primary device is in particular an active part coupled to an external power source and can inductively transmit power to the secondary device as a passive part.

[0003] In order to ensure an optimal power transmission, the arrangement of the primary and secondary devices relative to each other must meet certain boundary conditions. From EP 2 216 870 A2, a device for contactless power transmission is known. Here, it is determined whether the coils on the primary side and the secondary side are at a suitable distance from each other to allow efficient power transmission.

[0004] Furthermore, it should be ensured that there are no foreign objects within the effective range of the coupler device, so that energy does not flow to these foreign objects unintentionally and these foreign objects may heat up, which is dangerous. In order to circumvent this problem, a number of different methods have been proposed, in which foreign objects are usually detected in the coupler device during power transmission. Summary of the invention

[0005] The object of the present invention is to improve the known methods and systems so that foreign objects can be effectively detected and the coupler can be used in a variety of ways.

[0006] According to the invention, this object is achieved by a method having the features of the independent method claim and by a primary device having the features of the independent device claim. Advantageous embodiments are given in the dependent claims.

[0007] The object is therefore achieved by a method for operating a primary device for inductive power transmission, wherein at least a first operating mode and a second operating mode can be activated for the primary device. When the first operating mode is activated, a primary oscillating circuit of the primary device is excited so that secondary power can be transmitted to a secondary oscillating circuit of a secondary device coupled to the primary device. Furthermore, when the second operating mode is activated, the primary oscillating circuit is excited with standby power and a standby operating parameter is detected. In this case, a target object, in particular a metallic target object, is detected in a detection area as a function of the detected standby operating parameter and an output signal is generated.

[0008] In particular, in the second operating mode, in particular in the standby mode, a metal object is thus detected in the electromagnetic field of the primary device. In particular, in the second operating mode, the primary oscillating circuit is excited with a low voltage and a fixed frequency. This generates an electromagnetic field, and if a secondary device is detected, the first operating mode can also be activated and an inductive power transmission can be carried out.

[0009] The method expands the possibilities for use of the inductive coupler by making it possible to use the primary side as a sensor, for example as an end position switch, even during periods when no energy is being transmitted to the secondary device.

[0010] Thus, in the second operating mode, in particular in the standby state, the primary device can be used as a proximity switch, in particular when the primary device is not coupled to the secondary device; in a special construction of the method it can be provided that the primary device cannot be coupled to the secondary device in the second operating mode; however, normally the primary device will carry out coupling with the secondary device as soon as a secondary device ready for coupling is identified in the standby mode.

[0011] The term “standby” is understood here to mean a state in which the primary device is not coupled to the secondary device for inductive power transfer at a certain point in time.

[0012] In the second operating mode, the primary frequency for exciting the primary oscillating circuit can be set so that a certain standby power of the primary oscillating circuit is obtained. If a metal object is located within the effective range of the electromagnetic field of the primary oscillating circuit, the metal object absorbs the power of the electromagnetic field and thus changes the impedance of the overall system consisting of the primary oscillating circuit and the target object. This change can be detected, for example, by the increase in the primary current required to excite the primary oscillating circuit at the preset primary frequency.

[0013] Therefore, the increased primary current allows qualitative conclusions to be drawn about the presence of a target object in the effective range of the electromagnetic field of the primary oscillating circuit. In addition, the increased primary current allows quantitative assessment of the distance and / or position at which the target object is arranged relative to the primary oscillating circuit.

[0014] It can be provided that the primary device switches between the first and second operating modes depending on whether a secondary device is recognized and coupled to perform inductive power transfer in the first operating mode, or whether no secondary device is coupled and a target object, in particular a metallic foreign object, is detected in the standby state of the primary device.

[0015] In one embodiment, the first operating mode is activated when the primary device is coupled to the secondary device, in particular when a data connection to the secondary device is established in order to start the inductive power transmission.

[0016] For example, the first operating mode can be activated according to a user input or automatically when the secondary device is coupled to the primary device, in particular when the primary device is coupled to the secondary device for inductive power transmission and in particular for data transmission. If the second operating mode is activated at this time, it is particularly provided that the second operating mode is deactivated. Therefore, in particular, the first and second operating modes cannot be activated at the same time.

[0017] In one embodiment, a user input is detected and the first or second operating mode is activated as a function of the user input. In this case, in particular when the second operating mode is activated, the standby power of the primary oscillating circuit is determined as a function of the user input.

[0018] Thus, in particular, a dual use of the primary device can be set by the user by means of a user input. Alternatively or additionally, the primary device can automatically assess whether, when the secondary side is present and coupled, the function of inductive power transmission should be activated in the first operating mode or whether the function of metal detection should be activated in the second operating mode.

[0019] If the user determines that the primary side is to be used for metal detection, the standby power, i.e., the voltage used to generate the electromagnetic field, can be increased above a lower base value and / or the frequency of the primary oscillating circuit can be changed in the second operating mode. In this way, a greater effective range and more accurate metal detection can be achieved.

[0020] In the case where the primary side automatically switches between the first and second operating modes, the effective range can be designed to be smaller initially, but the effective range can be automatically expanded during metal detection through the same procedure as the above-mentioned user setting.

[0021] In a further embodiment, when the first operating mode is activated, a secondary power parameter of the secondary device is detected and a primary frequency for exciting the primary oscillating circuit is adjusted so that a preset value for the secondary power parameter is obtained.

[0022] In this case, in particular standby operating parameters such as the primary current intensity (I_pri) flowing from the intermediate capacitor into the amplifier and the primary oscillating circuit or the input current (I_in) of the primary device are detected.

[0023] In a further development, when the second operating mode is activated, the primary oscillating circuit is excited with a predefined primary frequency. In this case, the detected and evaluated standby operating parameters include in particular the primary current intensity (I_pri) or the input current (I_in) of the primary device.

[0024] In particular, power parameters of the primary device can be used as standby operating parameters of the primary device, such as the primary current intensity (I_pri) flowing from the intermediate capacitor into the amplifier and the primary oscillation circuit or the input current (I_in) of the primary device; in addition, the primary frequency of the primary oscillation circuit can be used as the standby operating parameter.

[0025] In one embodiment, the target object is detected in the detection area by comparing the power parameter with a predefined threshold value. The power parameter is determined based on calibration data or a characteristic curve.

[0026] In a further embodiment, during the detection of a target object in the detection area, a distance of the target object from the primary device or a distance of the target object from the primary oscillating circuit and / or a position of the target object relative to the primary oscillating circuit is determined.

[0027] For example, the distance can be determined based on a characteristic curve and / or based on a plurality of threshold values ​​which are respectively assigned to specific distances, wherein undershooting or overshooting of one of the specific distances is detected by comparison with the respectively assigned threshold values.

[0028] In one refinement, the output signal includes a switch signal and / or an alarm signal. For example, when the distance of the target object is below a certain value, a signal for turning the device on or off can be generated and output. In addition, if a foreign object is identified within the effective range of the primary device, a signal to prevent coupling and / or inductive power transfer can be generated. In addition, if the secondary power parameter does not enable power transfer during data transmission, a signal can be generated, that is, according to the signal, a coupling attempt is made with a secondary device identified nearby.

[0029] During the coupling process of the primary device and the secondary device, in particular a data connection is established, which is established in particular simultaneously and, if appropriate, in parallel with a connection for the inductive power transmission.

[0030] A primary device for inductive power transmission includes a primary oscillating circuit and a control unit. Here, the primary device is configured to: when a first operating mode is activated, transmit secondary power to a secondary oscillating circuit of a secondary device coupled to the primary device by means of the primary oscillating circuit; and when a second operating mode is activated, excite the primary oscillating circuit with standby power. Here, the control unit is configured to: when the second operating mode is activated, detect a standby operating parameter of the primary device; and detect a target object in a detection area according to the detected standby operating parameter and generate an output signal.

[0031] The control unit for switching between the first and the second operating mode and / or evaluating the output signal can be comprised in the primary device or can be provided as an external unit which is coupled to the primary device, in particular in terms of data technology.

[0032] The primary device is designed in particular for carrying out the method described here. The primary device therefore has the same advantages as the method and can be improved in a similar manner to the method embodiment described here.

[0033] In one construction of the primary device, the control unit is configured to: when the second operating mode is activated, adjust the primary frequency for exciting the primary oscillating circuit so as to obtain a preset primary frequency; and detect standby operating parameters, wherein the standby operating parameters particularly include the primary current intensity (I_pri) or the input current (I_in) of the primary device flowing from the intermediate circuit capacitor into the amplifier and the primary oscillating circuit.

[0034] During operation of the primary device as a proximity sensor in the second operating mode, for example, an input current (I_pri) into the primary oscillating circuit of the primary side is detected and evaluated. If the current I_pri rises above an application-related threshold value, a metal object is considered to be detected.

[0035] In one development, the primary device comprises an interface, in particular a network interface, for transmitting data to an external unit, and the control unit is configured to transmit the output signal to the external unit via the interface.

[0036] For example, the following information can be output to an external unit: whether a metallic object is located in the electromagnetic field of the primary device and / or at what distance and / or in what position the object is arranged relative to the primary device.

[0037] The interface can be configured, for example, to establish a data communication with a higher-level control level by means of IO-Link for evaluation. In this case, the primary device can be designed in particular as an independent IO-Link device. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Further details and advantages of the invention will now be explained in more detail based on the exemplary embodiments shown in the drawings.

[0039] In the attached picture:

[0040] Figure 1 An embodiment of a primary device and a secondary device coupled thereto for inductive power transfer are shown;

[0041] Figure 2 An embodiment of a primary device and a detected target object are shown;

[0042] Figure 3 An embodiment of the method is shown; and

[0043] Figure 4 and Figure 5 Exemplary measurement results are shown when the primary device is in operation. DETAILED DESCRIPTION

[0044] refer to Figure 1 , a system 10 for inductive power transfer having an embodiment of a primary device is described.

[0045] The system 10 includes a primary device 100 (here, a transmitter 100 ) and a secondary device 200 (here, a receiver 200 ).

[0046] The system 10 includes a primary device 100 and a secondary device 200 .

[0047] exist Figure 1 In the illustrated state, the primary device 100 and the secondary device 200 are coupled and perform contactless power transmission.

[0048] In this case, the first operating mode of the primary device 100 is activated.

[0049] In the first operating mode, the primary oscillating circuit of the primary device is excited so that the secondary power can be transmitted to the secondary oscillating circuit of the secondary device 200 coupled to the primary device 100 .

[0050] In this embodiment, the primary device 100 comprises a single coil 104 in a (primary) oscillating circuit for inductive energy transfer between the coupled primary device 100 and the secondary device 200 , wherein the primary device 100 acts as a transmitter 100 .

[0051] The input terminal 110 of the primary side supplies power to the primary device 100 , and the secondary device 200 outputs power on the secondary side via the output terminal 120 .

[0052] The primary device 100 further comprises a control unit 107 for adapting the oscillating circuit frequency as a function of load and distance, a voltage converter 101 with a constant output voltage, and a voltage intermediate circuit 102 for adapting the input voltage to the oscillating circuit voltage.

[0053] The primary device 100 further comprises an amplifier 103 , in particular a current-mode amplifier, for adapting a control signal of an actuation unit 107 to an oscillating circuit having a single coil 104 , and a current measuring unit 106 between the voltage intermediate circuit 102 and the amplifier 103 .

[0054] The primary device 100 further comprises a voltage measuring unit 105 on the voltage intermediate circuit 102 and an evaluation and control unit 107 for controlling the voltage converter 101 and the amplifier 103 .

[0055] The primary device 100 furthermore comprises an interface 108 for data transmission between the coupled primary device 100 and the secondary device 200 , wherein in particular the data connection to the secondary device 200 can be operated using the IO-Link method.

[0056] The secondary device 200 also comprises a single coil 204 in a (secondary) oscillating circuit for inductive energy transmission between the coupled primary device 100 and the secondary device 200 , wherein the secondary device 200 acts as a receiver 200 .

[0057] The secondary device 200 further comprises a rectifier 203 having a voltage intermediate circuit 202 for storing the received energy.

[0058] Furthermore, the secondary device 200 comprises a voltage converter 201 for adapting the intermediate circuit voltage to the output voltage and a current measuring unit 206 located between the voltage intermediate circuit 202 and the voltage converter 201 .

[0059] The secondary device 200 furthermore comprises a voltage measuring unit 205 on the voltage intermediate circuit 202 and an interface 208 for data transmission between the secondary device 200 and a primary device 100 coupled to the secondary device in a data-intensive manner.

[0060] refer to Figure 2 , describes an embodiment of the primary device 100 and the target object detected. Figure 1 The above-described contents and similar or identical elements are not described in detail again.

[0061] In the case shown here, the primary device 100 is as described in reference Figure 1 The device 200 is designed as described, but is not coupled to the secondary device 200 and does not carry out an inductive power transfer.

[0062] The second operating mode of the primary device 100 is activated, here the standby mode.

[0063] By means of the activated second operating mode, the primary oscillating circuit is supplied with standby power by means of the single coil 104 , and standby operating parameters are detected, according to which the target object 300 is detected in the detection area and an output signal is generated.

[0064] The target object 300 (here “foreign object” 300 ) is a metal body which is arranged at a distance d from the single coil 104 of the primary oscillating circuit.

[0065] In particular, in this embodiment, the “detection area” is defined according to the maximum distance at which the target object 300 can be detected, in particular the effective range of the electromagnetic field generated by the primary device 100 .

[0066] In this embodiment, the standby power fed to the primary oscillating circuit is significantly lower than the typical power used in inductive power transmission. For example, up to 5W, preferably up to 2W of standby power can be supplied.

[0067] refer to Figure 3 An exemplary embodiment of the method is described. In this case, the above exemplary embodiment of the primary device 100 is used in particular as the basis.

[0068] In step S1, the method begins in particular with a start routine which comprises, for example, initialization of the primary device 100. For the initialization, a data connection to a network can be used, via which, for example, the primary device 100 is connected to a control device.

[0069] In this example, the start routine of the first step S1 includes parameter configuration of the primary device. In particular, in order to activate the second operating mode, activate the function as a distance sensor or proximity switch, set the intermediate circuit voltage U ZK .

[0070] For example, a value of 5 V or 18 V can be set as the intermediate circuit voltage U ZK , wherein a smaller detection area can be achieved in the case of 5 V, while the detection area is increased in the case of 18 V.

[0071] In step S2 , the primary device 100 is operated in a standby mode, which in this exemplary embodiment corresponds to the second operating mode. In this state, the primary device is initialized and ready to detect an existing secondary side or metal object or target object 300 .

[0072] For example, with a 5V intermediate circuit voltage U ZK The maximum distance d is obtained in the case of limited effective range, e.g. for detecting secondary devices or metal objects. max It can be roughly up to 7 mm. In this case, the standby power during operation is about P≈1.0 W.

[0073] For example, with an intermediate circuit voltage U of 18V ZK The maximum distance d is used to obtain an extended effective range, for example for detecting secondary devices or metal objects. max It can be roughly up to 18 mm. In this case, the standby power during operation is about P≈2.5W.

[0074] In a further step S3 , it is checked whether the secondary device 200 is detected within the effective range of the electromagnetic field of the primary device 100 .

[0075] As already mentioned, this detection can be carried out, for example, at the intermediate circuit voltage U ZK 5V, until the maximum distance d max This is done for approximately up to 7 mm. ZK For example, in the 18V enlarged variant, the maximum distance d for detecting secondary devices max For example, it may be approximately up to 18 mm.

[0076] In a further step S4, if the secondary device 200 is detected, the first operating mode of the primary device 100 is activated and the primary device is coupled to the secondary device 200 for inductive power transmission. For this purpose, a data connection is established. Furthermore, a contactless inductive power transmission is performed by means of an electromagnetic field generated by the primary device 100 and received by the secondary device 200.

[0077] In the case of the limited effective range mentioned above, for example, the maximum distance for energy transmission may be d max <=7mm, in the case of the above-mentioned extended effective range, for example, the maximum distance for detecting metal objects can be d max >7mm.

[0078] In a further step S5 , the second operating mode of primary device 100 is activated if no secondary device 200 is present and / or coupled to primary device 100 . Primary device 100 then acts as a distance sensor or proximity switch which detects whether target object 300 is present in the detection range, wherein distance d is also determined.

[0079] In this exemplary embodiment, it is provided that when executing step S5, it is first checked whether the extended functionality of the primary device is set so that, in the absence of the secondary side, the primary device is to be operated as a distance sensor or proximity switch or detector for target object 300. If this is not set, in particular a third operating mode is activated in which no detection takes place in the standby state.

[0080] When the second operating mode is activated, a check is performed regularly in a cycle with fixed time intervals (in this example every 10 ms) to determine whether a secondary device is coupled and whether a switch should therefore be made to the first operating mode for inductive power transmission, if necessary.

[0081] As long as no secondary side is detected, in step S6 a detection of metallic target object 300 is carried out when the second operating mode is activated. For this purpose, it is checked whether a metallic object is located in the electromagnetic field of the primary device.

[0082] In order to detect target object 300 , in a second operating mode, the primary oscillating circuit of primary device 100 is energized at a fixed intermediate circuit voltage U ZK Operation. Under given fixed primary frequency and intermediate circuit voltage, the primary current I of the primary device 100 is detected and evaluated. pri and / or input current I in In the presence of a metal object, the primary current I pri Or input current I in The measured primary current I of the primary device 100 is then pri Or input current I in Conduct an assessment.

[0083] If the primary current I pri Or input current I in If a certain threshold value is exceeded, it can be assumed that a target object 300 made of metal is located within the detection area or the effective range of the primary device 100. The size of the detection area or the effective range depends in particular on the intermediate circuit voltage U ZK is related to the level of the intermediate circuit voltage U ZK In the higher case, the primary oscillator circuit operates at a higher standby power.

[0084] As an alternative or in addition to the comparison with the threshold value, the primary current I pri Or input current I in The distance d of the target object 300 from the primary device 100 is determined by the height of the current intensity. Generally, the closer the target object 300 is arranged to the primary device 100, the higher the measured value of the current intensity. For evaluation, the measured value is evaluated and the distance d is determined, in particular by means of a calibration value or by means of a calibration curve.

[0085] During the above-mentioned limited effective range operation, the maximum distance d of 7 mm can be used. max Detecting target object 300. In operation with an extended effective range, in particular with a higher standby power, the maximum distance d of, for example, 18 mm can be achieved. max Detection target object 300. In particular, with different intermediate circuit voltages U ZK In other examples, additional valid ranges may be obtained.

[0086] Then, a signal is output in step S7. In particular, a signal is output when the target object 300 is detected; alternatively or additionally, a signal may be output when the target object 300 is not detected.

[0087] Different output channels are conceivable for the output signal, depending on which interfaces are provided in the primary device 100 and how the output signal is to be processed further.

[0088] For example, the output signal may be output via a network such as IO-Link and may be transmitted to another device such as an IO master.

[0089] Furthermore, the primary device 100 can have a switching output which is switched on or off, for example, when a target object 300 is detected or when a distance d of the target object 300 exceeds or falls below a certain distance threshold.

[0090] It is also conceivable that when the target object 300 is detected, the intermediate circuit voltage U ZK Or the control frequency of the primary oscillating circuit. In this way, impermissible heating of metal objects can be avoided.

[0091] refer to Figure 4 and Figure 5 , exemplary measurement results during operation of the primary device are described. Here, the above-described embodiments of the primary device 100 and the method are based on the above-described embodiments.

[0092] exist Figure 4 In the case shown, the primary oscillating circuit of the primary device 100 is connected to an intermediate circuit voltage U of 5 V. ZK run.

[0093] exist Figure 5 In the case shown, the primary oscillating circuit of the primary device 100 is operated with an intermediate circuit voltage U ZK run.

[0094] They show that during metal detection at different distances d, 5V ( Figure 4 ) or 18V( Figure 5 ) of the intermediate circuit voltage U ZK 2 is an exemplary measurement result of the internal primary current I_pri and the input current I_in of the primary device 100 under FIG.

[0095] Here, the internal primary current I pri In particular, the current intensity required to excite the primary oscillating circuit during operation of the primary device 100 in order to supply the primary oscillating circuit with the required power at a given fixed primary frequency. pri Alternatively or in addition, the primary device input current I in , ie in particular the current intensity of the electrical power supplied to the primary device 100 from the outside.

[0096] In the curve region characterized by a specific value of distance d, a target object 300 made of metal is arranged at a distance d from the primary device 100. For the measurement, the distance d is 0 mm, 5 mm, 7 mm and 9 mm.

[0097] from Figure 4 and Figure 5 It can be seen from the curve that at a higher intermediate circuit voltage U of 18V ZK In this case, the measured current intensity is significantly higher than the baseline even at a larger distance d. That is, even at a distance d of, for example, 7 mm or 9 mm, the target object 300 can still be reliably detected.

[0098] In addition, from Figure 4 and Figure 5 It can be seen from FIG. 1 that the measured current intensity is related to the distance d, so the distance d can be inferred from the measured current intensity. Figure 4 and Figure 5 As calibration data, the primary device can be used in the second operating mode as a distance sensor or proximity sensor, which outputs a distance value or an output signal when a threshold value for the distance d is undershot. During calibration, a calibration curve can also be determined from the measured data by fitting, for example by fitting a polynomial, in which the dependence of the measured current intensity on the distance d is given.

[0099] Compared to known devices, the invention allows the functional range of the primary side of the inductive coupler to be expanded. By evaluating the signals of the primary side in a superordinate control device, a higher safety can be achieved, for example to prevent the primary side from colliding with metal objects.

[0100] Furthermore, it is possible to detect metal deposits, for example on the front cover of the primary device or the secondary device, at an early stage. Thus, maintenance and cleaning of the coupling system can be carried out in a targeted manner and wear and energy requirements can be reduced.

[0101] It is possible to prevent foreign objects in the electromagnetic field on the primary side from heating up and causing a hazard during the second operating mode, ie in the standby mode.

[0102] The method and the primary device of the present description allow various applications of the primary device as an extended function of a distance sensor or proximity switch. For example, a control optimization can be performed to position a (metal) tool carrier, wherein the inductive coupling of the primary device to the secondary side is performed only after positioning. Various (metal) devices can be listed, only some of which have secondary devices, which are suitable for coupling and inductive power transmission. In addition, in the second operating mode, the primary device can be used as an end position switch for approaching a target object; for example, when it is detected that the distance to the target object is small enough, the movement can be stopped and inductive energy transmission can be started if necessary. In addition, foreign objects on the primary side can be detected, which are caused, for example, by contamination in the area of ​​the primary device, such as the cover of the primary device, but it is not necessary to couple the primary device to the secondary device for this purpose. In addition, before the secondary side is installed and coupled, the installation of the primary side in a closed metal environment can also be checked.

[0103] List of Reference Numerals

[0104] 10 System

[0105] 100 Primary equipment; transmitter

[0106] 101 Voltage Converter

[0107] 102 voltage intermediate circuit; primary intermediate circuit

[0108] 103 Amplifier

[0109] 104 Single coil; Primary oscillating circuit with single coil and resonant capacitor

[0110] 105 Voltage measurement unit

[0111] 106 Current measurement unit

[0112] 107 Evaluation and Control Unit

[0113] 108 Primary interface; interface (data transmission)

[0114] 110 Input

[0115] 120 Output

[0116] 130 Data Transmission

[0117] 140 Power Transmission

[0118] 200 Secondary equipment; Receiver

[0119] 201 Voltage Converter

[0120] 202 Voltage intermediate circuit; Secondary intermediate circuit with single coil and resonant capacitor

[0121] 203 Rectifier

[0122] 204 single coil; secondary oscillation circuit

[0123] 205 Voltage measurement unit

[0124] 206 Current measurement unit

[0125] 207 Evaluation and Control Unit

[0126] 208 secondary interface; interface (data transmission)

[0127] 300 Target object, foreign object (metal)

[0128] d Distance

[0129] d max Maximum detection distance

[0130] Steps S1, S2, S3, S4, S5, S6, S7

Claims

1. A method for operating a primary device (100) for inductive power transmission, wherein: For the primary device (100), at least a first operating mode and a second operating mode can be activated; wherein, When the first operating mode is activated, the primary oscillating circuit (104) of the primary device (100) is excited so that secondary power can be transmitted to the secondary oscillating circuit (204) of the secondary device (200) coupled to the primary device (100); and wherein, When the second operation mode is activated, the primary oscillating circuit (104) is excited with standby power and standby operation parameters are detected; wherein According to the detected standby operation parameters, a target object (300) is detected in a detection area and an output signal is generated.

2. The method according to claim 1, It is characterized in that The first operating mode is activated when the primary device (100) is coupled to the secondary device (200), in particular when a data connection with the secondary device (200) is established to start inductive power transmission.

3. The method according to claim 1 or 2, It is characterized in that detecting user input and activating the first or second operating mode based on the user input; in In particular, when the second operating mode is activated, the standby power of the primary oscillating circuit (104) is determined according to the user input.

4. The method according to claim 1 or 2, It is characterized in that When the first operating mode is activated, detecting a secondary power parameter of the secondary device (200), in particular a primary current intensity (I_pri) or an input current (I_in) of the primary device; and The primary frequency for exciting the primary oscillating circuit is adjusted to obtain a preset value of the secondary power parameter.

5. The method according to claim 1 or 2, It is characterized in that When the second operating mode is activated, the primary oscillating circuit (104) is excited with a preset primary frequency; wherein The standby operating parameters include in particular the primary current intensity (I_pri) or the input current (I_in) of the primary device (100).

6. The method according to claim 4, It is characterized in that By comparing the power parameter with a preset threshold, the target object (300) is detected within the detection area; wherein Optionally, the power parameter is determined based on calibration data or a characteristic curve.

7. The method according to claim 1 or 2, It is characterized in that During detection of the target object (300) within the detection area, a distance (d) of the target object (300) from the primary device (100) is determined.

8. The method according to claim 1 or 2, It is characterized in that The output signal includes a switch signal and / or an alarm signal.

9. A primary device (100) for inductive power transmission, comprising a primary oscillator circuit (104); and A control unit (107); wherein The primary device (100) is configured to: - when the first operating mode is activated, transmitting secondary power to a secondary oscillating circuit (204) of a secondary device (200) coupled to the primary device (100) via the primary oscillating circuit (104); and - when the second operating mode is activated, the primary oscillating circuit (104) is excited with standby power; wherein The control unit (107) is configured to, when the second operating mode is activated, detect a standby operating parameter of the primary device (100); and detect a target object (300) in a detection area according to the detected standby operating parameter and generate an output signal.

10. The primary device (100) according to claim 9, It is characterized in that The control unit (107) is configured to: when the second operating mode is activated, excite the primary oscillating circuit (104) with a preset primary frequency; wherein the standby operating parameters include in particular the primary current intensity (I_pri) or the input current (I_in) of the primary device (100) flowing from the intermediate capacitor into the amplifier (103) and the primary oscillating circuit (104); and / or The primary device (100) comprises an interface, in particular a network interface, for transmitting data to an external unit, and the control unit (107) is configured to transmit the output signal to the external unit via the interface.

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