METHOD FOR OPERATING AN INDUCTIVE CHARGING DEVICE

Abstract

A method for operating an inductive charging device, in which a foreign object detection is carried out in at least one method step. It is provided that in at least one method step, the foreign object detection is carried out as a function of at least one characteristic power transmission variable.

Claims

1-10. (canceled)

11. A method for operating an inductive charging device, comprising: detecting, by the inducting charging device, a foreign object detection, the detecting being carried out as a function of at least one characteristic power transmission variable.

12. The method as recited in claim 11, further comprising: determining at least one characteristic precision variable of the foreign object detection as a function of the at least one characteristic power transmission variable.

13. The method as recited in claim 11, further comprising: determining at least one execution frequency of the foreign object detection as a function of the at least one characteristic power transmission variable.

14. The method as recited in claim 11, wherein the foreign object detection is carried out as a function of at least one change over time of an amplitude fluctuation and/or a gradient, of the characteristic power transmission variable.

15. The method as recited in claim 11, further comprising: suspending the foreign object detection as a function of a value of the characteristic power transmission variable undershooting a limit value.

16. The method as recited in claim 11, wherein the foreign object detection is carried out as a function of a value of the characteristic power transmission variable exceeding a limit value.

17. The method as recited in claim 1, further comprising: determining at least one execution period of time of the foreign object detection as a function of the at least one characteristic power transmission variable.

18. An inductive charging device, comprising: at least one open-loop and/or closed-loop control unit configure to carry out a foreign object detection as a function of at least one characteristic power transmission variable.

19. The inductive charging device as recited in claim 18, wherein the open-loop and/or closed-loop control unit is configured to determine at least one characteristic precision variable of the foreign object detection as a function of at least one characteristic power transmission variable.

20. The inductive charging device as recited in claim 18, wherein the open-loop and/or closed-loop control unit is configured to determine at least one execution frequency of the foreign object detection as a function of the at least one characteristic power transmission variable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Additional advantages result from the following description of the figures. The figures illustrate an exemplary embodiment of the present invention. The figures and the description of the figures include numerous features in combination. One skilled in the art will expediently also consider the features in isolation and combine them to form additional meaningful combinations.

[0020] FIG. 1 shows an inductive charging device in a schematic representation.

[0021] FIG. 2 shows a flow diagram of a method according to the present invention in a schematic representation.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0022] FIG. 1 shows an inductive charging device 10. In addition, FIG. 1 shows a battery-powered device 14 to be charged. Inductive charging device 10 is provided to charge battery-powered device 14. Inductive charging device 10 forms the primary side of a charge system 46. A rechargeable battery of a handheld tool represents battery-powered device 14 to be charged. However, it is also possible to use inductive charging device 10 for charging other rechargeable batteries that one skilled in the art might consider useful. FIG. 1 shows inductive charging device 10 and battery-powered device 14 to be charged during a charging operation. Battery-powered device 14 is placed on a top surface of a housing 16 of inductive charging device 10 and is wirelessly charged by way of a charging coil 18 of inductive charging device 10.

[0023] Inductive charging device 10 includes an open-loop and/or closed-loop control unit 12. Inductive charging device 10 has a charge electronics unit 48, which encompasses open-loop and/or closed-loop control unit 12. In addition, charge electronics unit 48 has an oscillating circuit 50. Oscillating circuit 50 includes charging coil 18.

[0024] During a charging operation of inductive charging device 10, a foreign object detection is carried out as a function of at least one characteristic power transmission variable. It is checked during the foreign object detection whether foreign objects that may have an adverse effect on a charging operation are located between inductive charging device 10 and battery-powered device 14 or are simply located only on inductive charging device 10 or may pose a risk to an operator or to inductive charging device 10. The foreign object detection is carried out in inductive charging device 10 using a method for foreign object detection with the aid of open-loop and/or closed-loop control unit 12 of inductive charging device 10. Open-loop and/or closed-loop control unit 12 of inductive charging device 10 is provided to execute the foreign object detection during a charging operation as a function of at least one characteristic power transmission variable.

[0025] FIG. 2 shows a flow diagram of a method for foreign object detection during a charging operation of the inductive charging device. In a first method step 30, the foreign object detection is initiated by open-loop and/or closed-loop control unit 12. The subsequent further execution of the foreign object detection takes place in a further method step 32 as a function of at least one characteristic power transmission variable. The characteristic power transmission variable in particular is a characteristic variable that characterizes, preferably in quantitative terms, an electromagnetic energy flow which is taking place during a charging operation between inductive charging device 10 and battery-powered device 14 to be charged. The characteristic power transmission variable is preferably developed as an electric power transmitted between inductive charging device 10 and battery-powered device 14 to be charged, as an electric current in a charging coil 18, an electric voltage applied at a charging coil 18, a temperature of a charging coil 18, an accepted power by a power supply unit, or the like. Closed-loop and/or open-loop control unit 12 has a sensor unit 20, which is provided to detect the characteristic power transmission variable during a charging operation of the inductive charging device in a continuous or quasi-continuous manner.

[0026] To optimize the foreign object detection, different parameters for adjusting the foreign object detection are able to be determined from the characteristic transmission power value with the aid of open-loop and/or closed-loop control unit 12. In at least one method step 34, at least one characteristic precision variable, such as a number of discrete frequency points and/or a number of sweep cycles, of the foreign object detection is determined as a function of the at least one characteristic power transmission variable. In at least one method step 36, at least one execution frequency, in particular a frequency of an execution of the foreign object detection during a charging operation, of the foreign object detection is determined as a function of the at least one characteristic power transmission variable. In particular, the execution frequency during a charging operation involving an average power transmission, e.g. a power transmission of between 5 W and 10 W, may be reduced in comparison with an execution frequency during a charging operation involving a high power transmission, e.g., a power transmission of more than 10 W. During charging operations that feature a low power transmission, an execution of a foreign object detection may be dispensed with completely. In at least one method step 38, at least one execution period of time, in particular a length of time of a sweep and/or a sweep cycle, of the foreign object detection is determined as a function of the at least one characteristic power transmission variable. Method steps 34, 36, 38 for determining parameters for the adjustment of the foreign object detection are able to be carried out in combination or individually.

[0027] Furthermore, in at least one method step 40, the foreign object detection is carried out as a function of at least one change over time, in particular of an amplitude fluctuation and/or a gradient, of the characteristic power transmission variable. In particular, a complete foreign object detection may be carried out once during the initialization of the charging operation. If no a fault occurs during the run through, then the foreign object detection is deactivated and the charging operation, during which energy from inductive charging device 10 is transmitted to battery-operated device 14, is started. During the energy transmission, open-loop and/or closed-loop control unit 12 monitors the charging operation for irregularities. If open-loop and/or closed-loop control unit 12 detects a change over time, in particular of an amplitude fluctuation and/or a gradient, of the characteristic power transmission variable, then the charging operation is interrupted and a foreign object detection initiated.

[0028] In at least one method step 42, the foreign object detection is suspended as a function of an undershooting of a limit value, in particular an undershooting of a lower limit value, by a value of the characteristic power transmission variable. In at least one method step 44, the foreign object detection is carried out as a function of an exceeding of a limit value, in particular an exceeding of an upper limit value, by a value of the characteristic power transmission variable. In particular, the execution of the foreign object detection of a charging operation is suspended when a lower limit value of a power transmission is undershot, for instance in a drop of the power transmission to a value below 5 W. When a specified limit value of the power transmission is exceeded, the foreign object detection is resumed again.