Device for triggering an electromagnetic actuator and method for testing a first inductor of an electromagenetic actuator

• US 20090219033A1
• Filed: 06/14/2006
• Published: 09/03/2009
• Est. Priority Date: 07/13/2005
• Status: Abandoned Application

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schumacher, Hartmut, Kottke, Thomas, Wirth, Jens
• Application Number:
  US11/988,701
• Publication Number:
  US 20090219033A1
• Time in Patent Office: Days
• US Class Current: 324/546
• CPC Class Codes: B60N 2/888 with arrangements for protecting against abnormal g-forces, e.g. by displacement of the head-rest
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: G01R 31/72 Testing of electric windings testing of transformers G01R31/62

Abstract

In a device for triggering an electromagnetic actuator and a method for testing an inductor of an electromagnetic actuator, the inductor is connected to a test circuit in such a way that a resonant circuit is created, and an evaluation circuit is provided that evaluates at least one electrical parameter of this resonant circuit to determine whether the inductance lies within predefined tolerances.

Claims

1-17. -17. (canceled)

18. A device for controlling an electromagnetic actuator having a first inductor, wherein the first inductor is supplied with current in the case of triggering of the actuator by the device, the device comprising:

a test circuit connected to the first inductor, wherein the test circuit is configured to monitor the first inductor and form a resonant circuit together with the first inductor; and

an evaluation circuit configured to record at least one electrical parameter of the resonant circuit and determine, as a function of the at least one electrical parameter, whether the first inductor enables the triggering of the actuator when supplied with current.

19. The device as recited in claim 18, wherein the test circuit has at least one first capacitor configured to form a resonant circuit connected in parallel to a first switch, and wherein the first switch is connected in series to the first inductor.

20. The device as recited in claim 19, wherein a first Zener diode is provided in parallel to the at least one first capacitor, and wherein the evaluation circuit is coupled to the first Zener diode.

21. The device as recited in claim 19, wherein the first switch is configured as a first low-side switch.

22. The device as recited in claim 21, wherein the device has a first test switch connected in parallel to the first inductor, the first switch, and the at least one first capacitor, and wherein the first test switch is closed for forming the resonant circuit.

23. The device as recited in claim 22, wherein a second test switch connected between an energy supply and the first inductor is provided.

24. The device as recited in claim 19, wherein a second inductor and a second switch are connected in series with one another, and wherein the second inductor and a second switch are connected in parallel to the first inductor and the first switch, and wherein a second capacitor is connected in parallel to the second switch.

25. The device as recited in claim 19, wherein a reference potential is provided that serves to charge the resonant circuit.

26. The device as recited in claim 25, wherein the test circuit is configured to enable the resonant circuit to oscillate around the reference potential.

27. The device as recited in claim 24, wherein a second Zener diode is connected in parallel to the second capacitor.

28. A method for testing a first inductor of an electromagnetic actuator, comprising:

connecting a test circuit to the first inductor for forming a resonant circuit;

supplying the resonant circuit with energy;

recording, by an evaluation circuit, at least one electrical parameter of the resonant circuit; and

testing, based on the at least one electrical parameter, whether the first inductor enables a triggering of the actuator.

29. The method as recited in claim 28, wherein an initial maximum of an oscillation of the resonant circuit is used as the at least one electrical parameter, and wherein the time of the initial maximum is compared with a predetermined tolerance range.

30. The method as recited in claim 28, wherein the frequency of the resonant circuit is used as the at least one electrical parameter.

31. The method as recited in claim 30, wherein the frequency of the resonant circuit is determined by ascertaining one of:

a) consecutive maxima;

b) consecutive zero crossings;

c) consecutive rising edges at predefined voltage values;

or d) consecutive falling edges at predefined voltage values.

32. The method as recited in claim 30, wherein in a first time period, one of a charging or discharging behavior of a first capacitor of the resonant circuit is determined, and wherein the capacitance of the first capacitor is determined based on the one of the charging or discharging behavior, and wherein the capacitance of the first capacitor is used together with the frequency of the resonant circuit for determining the inductance of the first inductor.

33. The method as recited in claim 28, wherein a first test switch connected in parallel to the first inductor is closed, after energy is supplied, to form the resonant circuit.

34. The method as recited in claim 28, wherein a second inductor is provided in parallel to the first inductor, and wherein the second inductor is connected to the test circuit to form the resonant circuit such that the first and second inductors are tested together.