Method for protecting an electrical modular unit from overcurrent damage

Patent metadata

Field	Value
Publication number	US-10530240-B2
Application number	US-201415301991-A
Country	US
Kind code	B2
Filing date	Apr 8, 2014
Priority date	Apr 8, 2014
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

A method protects an electrical modular unit from overcurrent damage by virtue of an inductive component converting electrical energy into magnetic and thermal energy, in which a bypass bypasses the inductive component during regular operation of the modular unit and current flows via the bypass. In order to reduce current spikes in the event of a surge current without significantly enlarging the semiconductor switching the circuit inductance for the commutation circuit, it is proposed that the bypass is opened by an overcurrent flowing through the bypass which is above a current value that can be achieved during fault-free operation of the modular unit, with the result that more current is forced through the inductive component than residual current flows through the bypass.

First claim

The invention claimed is:

1. A method for protecting an electric unit against overcurrent damage, which comprises the steps of:
providing an inductive component for converting electric power into magnetic and thermal energy, the inductive component having a busbar, embodied as a ribbon, in which the inductive component is formed by virtue of incisions in said ribbon;
bypassing the inductive component via a bypass during regular operation of the electrical unit where current flows via the bypass; and
opening the bypass when an overcurrent flows through the bypass, the overcurrent being above a current value reachable during the regular operation of the electric unit, so that more current is forced through the inductive component than residual current flowing through the bypass.

2. The method according to claim 1 , wherein the bypass is heated by the overcurrent and, even in a heated state, conducts some of the overcurrent in a same way as during the regular operation.

3. An electric unit, comprising:
an overcurrent buffer having an inductive component for converting electric power into magnetic energy and a bypass connected in parallel with said inductive component, said bypass embodied as a current switched overcurrent switch that opens by virtue of an overcurrent flowing through said bypass that is above a current value reachable during correct operation, so that more current is forced through said inductive component than residual current flowing through said bypass; and
said inductive component having a busbar, embodied as a ribbon, in which said inductive component is formed by virtue of incisions in said ribbon.

4. The electric unit according to claim 3 , wherein:
said busbar is a conductor; and
said bypass has an electrical conductor containing a positive temperature coefficient thermistor with a temperature coefficient α being at least twice as great as that of said conductor of said inductive component.

5. The electric unit according to claim 3 , wherein said busbar of said inductive component contains a first conductor having a conductor loop with a loop start and a loop end, said loop start is connected indirectly via said bypass to a second conductor and said loop end is connected directly to said second conductor.

6. The electric unit according to claim 5 , wherein said second conductor contains a conductor loop having a loop start and a loop end, and said loop starts of said first and second conductors are connected via said bypass to one another, and said loop ends of said first and second conductors are connected directly to one another.

7. The electric unit according to claim 3 , wherein said busbar is one of two busbars, shaped as flat conductors, that are situated flat above one another, form said inductive component and are connected to one another both via said bypass.

8. The electric unit according to claim 3 , wherein said busbar of said inductive component is one of two busbars, each of said busbars having a conductor loop embodied as a worm, said two worms being situated above one another and being connected to one another inside said worm directly and, in each case at a start of said worm, via said bypass.

9. The electric unit according to claim 7 , wherein said bypass is a plate disposed between said two busbars.

10. The electric unit according to claim 7 , wherein said bypass is a strip disposed between said two busbars.

11. The electric unit according to claim 7 , wherein said bypass is embodied as a U-shaped sheet having two U limbs lying flat against said busbars.

12. The electric unit according to claim 7 , wherein said overcurrent buffer has an insulator disposed between said two busbars and said bypass engages around said insulator.

13. The electric unit according to claim 3 , wherein:
said busbar is one of two busbars; and
said overcurrent buffer has a clamping brace and said two busbars are electrically connected to one another via said bypass and are mechanically pressed against one another in said clamping brace by means of surface pressure.

14. The electric unit according to claim 4 , wherein the temperature coefficient α is at least ten times greater than that of said conductor of said inductive component.

15. A converter module, comprising:
an electric unit containing an overcurrent buffer having an inductive component for converting electric power into magnetic energy and a bypass connected in parallel with said inductive component, said bypass embodied as a current switched overcurrent switch that opens by virtue of an overcurrent flowing through said bypass that is above a current value reachable during correct operation, so that more current is forced through said inductive component than residual current flowing through said bypass, said inductive component having a busbar, embodied as a ribbon, in which said inductive component is formed by virtue of incisions in said ribbon;
two DC supply lines connected to said electric unit; and
a capacitor disposed between said DC supply lines.

Assignees

• Siemens Ag

Inventors

• Schmitt Daniel

Classifications

• H02M7/217

  using semiconductor devices only · CPC title

• H02M7/003

  Constructional details, e.g. physical layout, assembly, wiring or busbar connections · CPC title

• H01F38/023

  of inductances · CPC title

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H01F27/40 Primary

  Structural association with built-in electric component, e.g. fuse · CPC title