Electrical circuit for transmitting state information, in particular concerning some member in railway rolling-stock, and an electrical system incorporating such a circuit

• US 6,483,431 B2
• Filed: 03/26/2001
• Issued: 11/19/2002
• Est. Priority Date: 03/31/2000
• Status: Expired due to Fees

• Current Assignee: Alstom SA
• Original Assignee: Alstom SA
• Inventors: Prince, Ladimir, Bert, Michel
• Primary Examiner(s): Oda, Christine K.
• Application Number:
  US09/816,247
• Publication Number:
  US 20010026227A1
• Time in Patent Office: 603 Days
• Field of Search: 340/509, 340/524, 340/525, 340/679
• US Class Current: 340/509
• CPC Class Codes: H01H 1/605 Cleaning of contact-making surfaces by relatively high voltage pulses
• CPC Class Codes: H01H 9/167 Circuits for remote indication

Abstract

An electrical circuit for transmitting an item of information relating to the state of a parameter or of a piece of equipment, in particular for application in the railway field. The circuit includes a device for regulating the current flowing through the switch, including a switch device for switching over connections and having an inductive energy storage device and a capacitive energy storage device which, under steady conditions, alternate between being a device for storing and a device for restoring a fraction of the energy of the electrical circuit depending on the alternating state of the connections, as defined by the switch device. The invention also provides an electrical system incorporating such a circuit.

Claims

1. An electrical circuit for transmitting the state of one of a parameter and of a piece of equipment and operative to be connected to terminals of a power supply battery, the circuit comprising:

an isolated link between said electrical circuit and an output for sending an item of state information; and

a state switch whose open or closed position is representative of the state information and determines, while not testing, whether or not a current flows in said electrical circuit;

the electrical circuit transmitting state information from the state switch to the output via the isolated link;

the electrical circuit comprising means for regulating the magnitude of the current flowing through the state switch, said means for regulating comprising switch means, connections between component elements of the electrical circuit and comprising inductive energy storage means in series with the state switch and capacitive energy storage means which, under steady conditions, alternate between constituting means for storing and means for restoring a fraction of the energy of said electrical circuit, depending on the alternating state of said connections between the component elements of the electrical circuit, as determined by the switch means.

2. An electrical circuit according to claim 1, wherein the isolated link is connected in series with the state switch.

3. An electrical circuit according to claim 1, wherein the means for regulating the current through the state switch further include means for monitoring a magnitude characteristic of the state of the electrical circuit and for controlling the switch means to alternate connections between the elements constituting the electrical circuit as a function of the state of said electrical circuit.

4. An electrical circuit according to claim 3, wherein said means for monitoring a magnitude characteristic of the state of the electrical circuit and for periodically controlling the switch means also form the isolated link and for this purpose are provided with said outlet for sending the information and are suitable for sending this information on the basis of processing said characteristic magnitude, in particular on the basis of the duty ratio.

5. An electrical circuit according to claim 3, wherein the peak value during a period of the current flowing through the state switch constitutes said magnitude characteristic of the state of the electrical circuit.

6. An electrical circuit according to claim 3, further comprising means for testing correct operation of the electrical circuit, the means for testing including:

a controlled test switch and a test battery connected in a first series circuit which is in turn connected in parallel with a second series circuit including the state switch and a location for connecting the power supply battery; and

an automatic test unit connected to the control terminal of the controlled test switch and to the outlet for transmitting state information, and wherein the automatic test unit, also connected to the means for monitoring a magnitude that is characteristic of the state of the electrical circuit and for operating the switch means of the connections in alternation, is suitable for holding said switch means in at least one current cut-off position in said electrical circuit.

7. An electrical circuit according to claim 1, wherein the switch means for switching the connections between the elements constituting the electrical circuit establish at least the following connections in an alternation:

the inductive energy storage means, the state switch, the power supply battery, and the capacitive energy storage means in series in a closed loop during a first stage, under steady conditions, in which the inductive energy storage means restore a quantity of energy which is stored in the capacitive energy storage means; and

the inductive energy storage means, the state switch, and the capacitive energy storage means in series in a closed loop during a second stage, under steady conditions, in which the capacitive energy storage means restore a quantity of energy which is stored by the inductive energy storage means;

the polarity of the connections between the inductive energy storage means and the capacitive energy storage means being inverted between the first and second stages.

8. An electrical circuit according to claim 1, wherein the inductive energy storage means and the capacitive energy storage means comprise respectively:

an inductor in series with the state switch; and

a capacitor;

wherein the electrical circuit has first and second parallel-connected branches in series with the state switch and the inductor, and includes a resistor in parallel with the state switch and the inductor, and connected to a point of the second branch, the capacitor being connected in the second branch; and

wherein the means for switching the connections comprises means for directing the current flowing through the state switch and the inductor through the first and second branches in alternation.

9. An electrical circuit according to claim 8, wherein the isolated link is connected in the first branch.

10. An electrical circuit according to claim 8, wherein the isolated link is connected in series with the capacitor in the second branch.

11. An electrical circuit according to claim 8, wherein the isolated link is connected in series with the resistor.

12. An electrical circuit according to claim 8, wherein the period during which the current flowing through the state switch and the inductor flows successively through the first branch and then through the second branch, and the duty ratio which is equal to the time said current flows through the first branch divided by said period, are respectively fixed and variable, and are determined by the means for monitoring the magnitude characteristic of the state of the electrical circuit and for periodically controlling the switch means.

13. An electrical circuit according to claim 8, wherein the means for directing the current passing through the state switch and the inductor alternately through the first branch and through the second branch comprise a controlled switch connected in the first branch and a diode connected in the second branch between firstly one of the two junctions between the first and second branches, and secondly the connection point between the resistor and the second branch, the capacitor lying between the other one of said two junctions between the first and second branches, and the connection point of the resistor and the second branch.

14. An electrical circuit according to claim 13, wherein the isolated link is connected in series with the diode.

15. An electrical circuit according to claim 8, wherein the potential at the point where the resistor is connected to the second branch constitutes a magnitude characteristic of the state of the electrical circuit.

16. An electrical circuit according to claim 8, wherein the voltage across the terminals of the resistor constitutes a magnitude characteristic of the state of the electrical circuit.

17. An electrical circuit according to claim 1, wherein the isolated link consists in an optocoupler.

18. An electrical circuit according to claim 1, wherein the isolated link consists in a transformer.

19. An electrical circuit according to claim 1, wherein the isolated link consists in a transformer connected in series with the state switch and whose primary winding also forms at least a portion of the inductive energy storage means.

20. An electrical circuit according to claim 1, further including means for testing correct operation thereof, independently of the position of the state switch.

21. An electrical circuit according to claim 20, wherein the means for testing correct operation of the electrical circuit include:

a controlled test switch and a test battery connected in a first series circuit which is in turn connected in parallel with a second series circuit including the state switch and a location for connecting the power supply battery; and

an automatic test unit connected to the control terminal of the controlled test switch and to the outlet for transmitting state information.

22. An electrical circuit according to claim 20, wherein the means for testing correct operation of the electrical circuit include:

a controlled test switch connected in parallel with the state switch, the assembly being connected in series with a location for connecting the power supply battery that is also to operate as a test battery; and

an automatic test unit connected to the control terminal of the controlled test switch and to the outlet for transmitting state information.

23. An electrical circuit according to claim 20, wherein the means for testing correct operation of the electrical circuit include at least one protective diode connected in series with the state switch to block current coming from the controlled test switch.

24. An electrical circuit according to claim 23, wherein the means for testing correct operation of the electrical circuit include another protective diode connected in series with the controlled test switch to block current coming from the state switch.

25. An electrical system for transmitting a plurality of items of state information, the system comprising a power supply battery and a plurality of electrical circuits according to claim 1, each serving to transmit one item of state information and all connected in parallel across the terminals of said battery.

26. An electrical system according to claim 25, the system being mounted on board a railway train, each state switch being associated with one of a member and a piece of equipment of said railway train, to monitor the state or the position thereof.