Method for foreign object detection for an induction charging device and induction charging device

• US 10,326,317 B2
• Filed: 08/26/2015
• Issued: 06/18/2019
• Est. Priority Date: 10/01/2014
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Krupezevic, Dragan, Gonda, Martin
• Primary Examiner(s): Hollington, Jermele M
• Assistant Examiner(s): Rhodes-Vivour, Temilade S
• Application Number:
  US15/516,246
• Publication Number:
  US 20170302111A1
• Time in Patent Office: 1,392 Days
• CPC Class Codes: G01V 3/101 by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil measuring impedance or characteristics derived therefrom G01R27/00, e.g. quality factor G01R27/26
• CPC Class Codes: H01L 21/00 Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
• CPC Class Codes: H01L 2221/00 Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H04W 4/00 Services specially adapted for wireless communication networks; Facilities therefor

Abstract

A method for foreign object detection for an induction charging device is described, including an oscillator circuit, in particular, for a hand-held power tool, a resonance frequency and an associated actual quality of the oscillator circuit being detected and the actual quality is subsequently compared to a setpoint quality as a function of the resonance frequency and a decision is made about the presence of a foreign object based on a defined setpoint quality range. The method provides that an upper limit and/or a lower limit of the setpoint quality range and the profile of the actual quality are adapted to one another. Also described is an induction charging device including an oscillator circuit and a control and regulating unit for carrying out the method.

Claims

1. A method for foreign object detection for an induction charging device including an oscillator circuit, the method comprising:

detecting a resonance frequency and an associated actual quality of the oscillator circuit;

subsequently comparing the actual quality to a setpoint quality as a function of the resonance frequency;

determining whether a foreign object is present based on a defined setpoint quality range; and

adapting at least one of an upper limit and a lower limit of the setpoint quality range and a profile of the actual quality to one another.

2. The method for foreign object detection as recited in claim 1, wherein the induction charging device is for a hand-held power tool.

3. The method for foreign object detection as recited in claim 1, further comprising:

changing the at least one of the upper limit and the lower limit of the setpoint quality range within a maximum setpoint quality and a minimum setpoint quality in such a way that a profile of the at least one of the upper limit and the lower limit of the setpoint quality range largely corresponds to the profile of the actual quality.

4. The method for foreign object detection as recited in claim 1, further comprising:

correcting the actual quality by a correction factor in such a way that the profile is at least one of linear and constant.

5. The method for foreign object detection as recited in claim 4, wherein a distance of the at least one of the upper limit and the lower limit of the setpoint quality range is maintained essentially the same with respect to the profile of the corrected actual quality.

6. A method for foreign object for an induction charging device including an oscillator circuit, the method comprising:

detecting a resonance frequency and an associated actual quality of the oscillator circuit;

subsequently comparing the actual quality to a setpoint quality as a function of the resonance frequency;

determining whether a foreign object is present based on a defined setpoint quality range;

adapting at least one of an upper limit and a lower limit of the setpoint quality range and a profile of the actual quality to one another;

correcting the actual quality by a correction factor in such a way that the profile is at least one of linear and constant; and

multiplying the at least one of the upper limit and the lower limit of the setpoint quality range by the correction factor.

7. The method for foreign object detection as recited in claim 6, wherein the correction factor is defined as an inverse of the actual quality.

8. An induction charging device, comprising:

an oscillator circuit; and

a control and regulating unit, wherein the control and regulating unit;

detects a resonance frequency and an associated actual quality of the oscillator circuit,

subsequently compares the actual quality to a setpoint quality as a function of the resonance frequency,

determines whether a foreign object is present based on a defined setpoint quality range, and

adapts at least one of an upper limit and a lower limit of the setpoint quality range and a profile of the actual quality to one another.