Electronic circuit breaker

• US 20060120000A1
• Filed: 09/14/2005
• Published: 06/08/2006
• Est. Priority Date: 03/14/2003
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: Power-One Incorporated (ABB Limited)
• Inventors: Cincinelli, Lorenzo, Fiesoli, Guido, Bittoni, Francesco
• Granted Patent: US 7,630,185 B2
• Time in Patent Office: Days
• US Class Current: 361/93.100
• CPC Class Codes: H02H 3/006 Calibration or setting of parameters
• CPC Class Codes: H02H 3/025 Disconnection after limiting, e.g. when limiting is not sufficient or for facilitating disconnection
• CPC Class Codes: H02H 3/08 responsive to excess current responsive to abnormal temperature caused by excess current H02H5/04
• CPC Class Codes: H02H 3/087 for dc applications

Abstract

An electronic circuit breaker includes an input for connection to a power-supply and an output for connection to a load. Connected in circuit between the input and the output are a switch, a relay, and a limitation block, which controls the switch to cause at least partial inhibition thereof in the event of an over-current condition. Also provided is a microprocessor which is connected to the limitation block to inhibit power supply to the load.

Claims

1. An electronic circuit breaker with an input for connection to a power-supply and an output for connection to a load, comprising:

an interrupt block connected in circuit between the input and the output, the interrupt block including at least one switch functional to inhibit current flow from the input to the load and an isolation device functional to interrupt current flow to the load;

a limitation block electrically coupled to the interrupt block, the limitation block functional to cause the switch to partially inhibit current flow to the load during a delay period in the event of an over-current condition to the load; and

a microprocessor operably coupled to the limitation block and to the isolation device, the microprocessor operable to cause the isolation device to interrupt current to the load after the delay period in the event of an over-current condition.

2. The circuit breaker according to claim 1, wherein said switch is a semiconductor device.

3. The circuit breaker according to claim 1, wherein said isolation device is a relay.

4. The circuit breaker according to claim 2, wherein said isolation device is a relay.

5. The circuit breaker according to claim 1, wherein said microprocessor is programmed for controlling switching of isolation device and of said switch in such a way that switching of the isolation device occurs substantially at zero voltage.

6. The circuit breaker according to claim 2, wherein said microprocessor is programmed for controlling switching of said isolation device and of said switch in such a way that switching of the isolation device occurs substantially at zero voltage.

7. The circuit breaker according to claim 3, wherein said microprocessor is programmed for controlling switching of said isolation device and of said switch in such a way that switching of the isolation device occurs substantially at zero voltage.

8. The circuit breaker of claim 7 wherein said limitation block comprises an operational amplifier having an inverting input and a non-inverting input and wherein a signal proportional to the current that traverses said circuit breaker is applied to the inverting input and a reference voltage is applied to the non-inverting input.

9. The circuit breaker according to claim 8, wherein said reference voltage is programmable by means of said microprocessor.

10. The circuit breaker according to claim 8, wherein said microprocessor is connected to the inverting input of said operational amplifier.

11. The circuit breaker according to claim 8, wherein said switch is connected to an output of said operational amplifier.

12. The circuit breaker according claim 8, wherein a fuse is connected in circuit between the output of said operational amplifier and said switch.

13. The circuit breaker according to claim 1, comprising at least one catastrophic-protection device in circuit between the input and the output.

14. The circuit breaker according to claim 1, comprising at least one sensing resistor connected in circuit for determining an amount of current that flows through said circuit breaker.

15. The circuit breaker according to claim 10, wherein said at least one catastrophic-protection device is connected in series with said at least one switch.

16. The circuit breaker according to claim 14, wherein said at least one sensing resistor is connected in series with said at least one switch.

17. The circuit breaker according to claim 1, wherein said microprocessor is programmable for intervening with a pre-set delay with respect to the partial inhibition of said switch.

18. The circuit breaker according to claim 1, wherein said microprocessor is connected to a temperature sensor and is programmed to cause opening of the circuit in the event of overheating.

19. The circuit breaker according to claim 1, wherein said microprocessor comprises an input/output terminal for programming and/or communication external to said circuit breaker.

20. The circuit breaker according to claim 1, wherein said microprocessor is associated to a memory for storing the parameters for operation of the circuit breaker.

21. The circuit breaker according to claim 1, comprising a plurality of switches, each of which is associated to a corresponding limitation block, said switches being set in parallel with respect to one another.

22. The circuit breaker according to claim 21, comprising an individual relay associated to said switches, which are arranged in parallel with respect to one another.

23. The circuit breaker according to claim 1, wherein said microprocessor receives an input signal proportional to a voltage at the input to the circuit breaker and is programmed to cause opening of the circuit by the circuit breaker when said voltage exceeds a pre-determined value.

24. The circuit breaker according to claim 1, wherein said microprocessor is programmed to cut off power supply to the load by bringing said switch and said isolation device into an open condition after a time delay following partial inhibition of said switch.

25. The circuit breaker according to claim 24, wherein said time delay is programmable.

26. The circuit breaker according to claim 24, wherein said time delay is variable according to a voltage drop across said switch.

27. The circuit breaker according to claim 25, wherein said time delay is variable according to a voltage drop across said switch.

28. The circuit breaker according to claim 24, wherein said microprocessor is arranged to detect a voltage value which is a function of a voltage drop across said switch and wherein said microprocessor is programmed to modify said time delay as a function of said detected voltage value.

29. The circuit breaker according to claim 28, wherein said limitation block comprises an operational amplifier, to a first input of which there is applied a signal proportional to the current that traverses said circuit breaker, and to the second input of which there is applied a reference voltage

30. The circuit breaker according to claim 29, wherein said reference voltage is programmable by means of said microprocessor.

31. The circuit breaker according to claim 1, wherein said at least one switch includes a MOSFET.

32. A method for controlling a circuit breaker, including the steps of:

arranging at least an electronically controllable switch and a isolation device between an input and an output of said circuit breaker;

providing a microprocessor controlling said switch;

powering a load through said circuit breaker;

detecting a current flowing through said circuit breaker;

when the current exceeds a current threshold, partially inhibiting said switch;

upon a given time delay following partial inhibition of said switch, if said current still exceeds said threshold, cutting off power supply through said circuit breaker by opening said switch and said isolation device.

33. The method according to claim 32, including the steps of providing a limitation block controlling said at least one switch and partially inhibiting said switch by means of said limitation block.

34. The method according to claim 33, wherein said time delay is programmable.

35. The method according to claim 34, wherein said time delay is programmable.

36. The method according to claim 32, further including the steps of:

detecting a voltage drop which is a function of the voltage drop across said at least one switch;

calculating said time delay as a function of said detected voltage drop.

37. The method according to claim 33, further including the steps of:

detecting a voltage drop which is a function of the voltage drop across said at least one switch;

calculating said time delay as a function of said detected voltage drop.

38. The method according to claim 32, further including the step of detecting an input voltage across input terminals of said circuit breaker, cutting off said circuit breaker when said input voltage exceeds a pre-set overvoltage value.