Circuit arrangement for operating a solenoid actuator

• US 6,646,851 B1
• Filed: 07/10/2000
• Issued: 11/11/2003
• Est. Priority Date: 07/09/1999
• Status: Expired due to Fees

• Current Assignee: Wabco GmbH (Wabco Holdings Incorporated)
• Original Assignee: Wabco GmbH (Wabco Holdings Incorporated)
• Inventors: Gudat, Wolfgang
• Primary Examiner(s): Sircus, Brian
• Assistant Examiner(s): Rodriguez, Isabel
• Application Number:
  US09/612,890
• Time in Patent Office: 1,219 Days
• Field of Search: 318/254, 361/160, 361/115
• US Class Current: 361/160
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: H02P 25/08 Reluctance motors
• CPC Class Codes: H02P 29/032 Preventing damage to the motor, e.g. setting individual current limits for different drive conditions

Abstract

A circuit arrangement for operating a solenoid actuator, for example, an electric motor provided in the form of a switched reluctance motor, permits operation of the motor in the event of malfunction or failure of part of an energy supply. The circuit arrangement advantageously includes an auxiliary battery serving as a redundance in addition to a main battery. The auxiliary battery is smaller and has a lower nominal voltage than the main battery. In order to permit continued operation of the electric motor in the event of failure, with a nominal operating voltage which is adapted to the nominal voltage of the main battery, a capacitor which can be switched on and off is connected in series to the batteries. An energy quantity can be accumulated in the capacitor by switching the current switching through an exciter winding of the electric motor in the manner of a switching regulator, whereby the nominal voltage of the capacitor finally exceeds the voltage in the auxiliary battery. When a sufficient quantity of energy has been accumulated, the electric motor can be actuated for a short time by means of the energy accumulated in the capacitor. Electrically actuated braking systems in commercial vehicles represent a significant and preferred area of application for the invention.

Claims

1. A circuit arrangement for operating a solenoid actuator comprising:

an electrical energy supply device;

a first switching device via which the actuator is connectable to the energy supply device;

an energy feed-back device located between the energy supply device and the actuator for feeding back an energy quantity stored in the actuator into the energy supply device when the first switching device is opened, the energy supply device including at least one energy output device and at least one energy storage for transmitting and receiving energy; and

a second switching device via which the energy storage is connectable to an energy feed-back device, such that a desired energy reserve is accumulated step by step in the energy storage by an alternating opening and closing of the first and the second switching devices,

wherein the energy output device includes a main energy output device and an auxiliary energy output device parallel to the main energy output device, and wherein the step by step accumulation of the desired energy reserve in the energy storage is carried out in the event of defect or failure of the main energy output device.

2. A circuit arrangement according to claim 1, wherein the desired energy reserve is accumulated in the energy storage by opening the first switching device to stop the transfer of energy between the energy output device and the actuator, and by closing the second switching device to feed back energy stored in the actuator via the energy feed-back device to the energy storage, wherein the accumulated energy storage is subsequently transmittable to the actuator by simultaneously closing the first switching device and the second switching device, when required for operation of the actuator.

3. A circuit arrangement according to claim 2, wherein the first switching device comprises a first switch connected between a first side of the actuator and a first side of the energy supply device, and a second switch connected between a second side of the actuator and a second side of the energy supply device, both first and second switches of the first switching device opening and closing simultaneously, and wherein the energy feed-back device bridges the first switching device.

4. A circuit arrangement according to claim 3, wherein the energy feed-back device comprises a first diode and a second diode, the first diode being connected from the connection of the first switch and the first end of the actuator to the connection of the second switch and the second side of the energy supply device in the direction of flow, and the second diode being connected from the connection of the second switch and the second side of the actuator to the connection of the first switch and the first side of the energy supply device in the direction of flow.

5. A circuit arrangement according to claim 4, wherein the energy supply device comprises first and second circuits connected in parallel, the first circuit comprising the energy output device connected in series with an energy supply diode, and the second circuit comprising the energy storage connected in series with the second switching device, such that the energy supply diode is connected to the second switching device at the first side of the energy supply device, and the energy output device is connected to the energy storage at the second side of the energy supply device.

6. A circuit arrangement according to claim 5, wherein the energy output device is a battery, the energy storage is a capacitor, and the first and second switching devices are electronically controllable switches.

7. A circuit arrangement according to claim 1, wherein the energy reserve is accumulated step by step in the energy storage when the actuator produces an actuating force in combination with the energy output device that is below a desired value.

8. A circuit arrangement according to claim 7, wherein the first switching device is actuatable in such a manner that the actuator does not substantially execute any actuating movement for the step by step accumulation of the energy reserve in the energy storage.

9. A circuit arrangement according to claim 1, wherein at least on e of the main energy output device and the auxiliary energy output device is operable for output and not input of electrical energy.

10. A circuit arrangement according to claim 1, wherein at least one of the main energy output device and the auxiliary energy output device is provided with an energy source connected in series with a component which allows current to pass only in the direction of the energy feed-back device.

11. A circuit arrangement according to claim 10, wherein the energy source includes a rechargeable battery.

12. A circuit arrangement according to claim 1, wherein at least one of the main energy output device and the auxiliary energy output device is provided with an energy source to which an additional switching device is connected in series.

13. A circuit arrangement according to claim 12, wherein the energy source includes a rechargeable battery.

14. A circuit arrangement according to claim 1, wherein a nominal voltage of the auxiliary energy output device is substantially lower than a nominal voltage of the main energy output device.

15. A circuit arrangement according to claim 1, further comprising a control module which provides electronic control signals to the first and second switching devices.

16. A circuit arrangement according to claim 1, wherein the actuator is an electric motor.

17. A circuit arrangement according to claim 16, wherein the electric motor is a D.C. motor including an armature, a commutator and two electrical connections.

18. A circuit arrangement according to claim 16, wherein the electric motor includes exciter windings having electrical connections via which electrical energy is suppliable to said exciter windings.

19. A circuit arrangement according to claim 18, wherein:

the electric motor includes rotor poles and stator poles corresponding to the exciter windings; and

the first switching device is actuatable in such manner for the step by step accumulation of the energy reserve in the energy storage that particular ones of the exciter windings of the electric motor whose stator poles are closest to the rotor poles are connected to the energy output device.

20. A circuit arrangement according to claim 18, wherein the first switching device is actuatable in such manner for the step by step accumulation of the energy reserve in the energy storage that several or all exciter windings of the electric motor are connectable at the same time to the energy output device.

21. A circuit arrangement according to claim 16, wherein the electric motor is a switched reluctance motor.

22. A circuit arrangement according to claim 1, wherein the actuator is a solenoid.

23. A circuit arrangement according to claim 22, wherein the solenoid comprises a solenoid valve.

24. A method of operating a solenoid actuator, comprising:

connecting the actuator in a circuit arrangement including an electrical energy supply device, a first switching device via which the actuator is connectable to the electrical energy supply device, an energy feed-back device located between the energy supply device and the actuator which feeds back an energy quantity stored in the actuator into the energy supply device when the first switching device has been opened, the energy supply device including at least one energy output device and at least one energy storage for transmitting and receiving energy, and a second switching device via which the energy storage is connectable to the energy feed-back device; and

alternating opening and closing the first and the second switching devices such that a desired energy is accumulated step by step in the energy storage,

wherein the energy output device includes a main energy output device and an auxiliary energy output device parallel to the main energy output device, and wherein the step by step accumulation of the desired energy in the energy storage is carried out in the event of defect or failure of the main energy output device.

25. A method of operating a solenoid actuator, comprising:

connecting the actuator to an electrical energy source;

disconnecting the actuator from the electrical energy source and feeding back an energy quantity stored in the actuator into an energy storage; and

alternating repeating said steps of connecting and disconnecting, whereby a desired energy reserve is accumulated step by step in the energy storage, wherein the electrical energy source includes at least one energy output device and an auxiliary energy output device parallel to the main energy output device, and wherein the step by step accumulation of the desired energy reserve in the energy storage is carried out in the event of defect or failure of the main energy output device.

26. A method according to claim 25, wherein:

the actuator is an electric motor including exciter windings, rotor poles and stator poles corresponding to the exciter windings; and

only the exciter windings of the electric motor whose stator poles are closest to the rotor poles are connected to the auxiliary energy source in said step of connecting.

27. A method according to claim 25, further comprising:

transmitting the energy reserve collected in the energy storage to the actuator when required for operation thereof.

28. A method according to claim 25, wherein the energy reserve is accumulated step by step in the energy storage when the actuator produces an actuating force in combination with the energy output device that is below a desired value.

29. A method according to claim 25, wherein said step of connecting does not substantially execute any actuating movement of the actuator.

30. A method according to claim 25, wherein:

the electrical energy source is an auxiliary energy source; and

the step by step accumulation of the energy reserve in the energy storage is carried out in the event of operational failure of a main energy source.

31. A method according to claim 30, wherein a nominal voltage of the auxiliary energy source is substantially lower than a nominal voltage of the main energy source.

32. A method according to claim 25, wherein:

the actuator is an electric motor having exciter windings; and

said step of alternatingly repeating includes connecting several or all exciter windings of the electric motor at the same time to the electrical energy source.