SUPPLY DEVICE FOR AN ELECTRICAL MODULE HAVING A FUSE ELEMENT

Abstract

A supply device supplies electrical power to an electrical assembly at a high-voltage potential. The supply device has a series circuit composed of at least one series resistor and a supply unit. The series circuit can be connected to an energy store and the supply unit can be connected to the assembly that is to be supplied with power. The supply device further has a fuse element, by which a short-circuit current through the supply unit can be electrically interrupted in the event of a short circuit.

Claims

1. A supply device for supplying electrical power to an electrical assembly at a high-voltage potential, the supply device comprising: a series circuit composed of at least one series resistor and a supply unit, said series circuit to be connected to an energy store and said supply unit to be connected to the electrical assembly that is to be supplied with the electrical power; and a fuse element, by means of said fuse element a short-circuit current through said supply unit can be electrically interrupted in an event of a short circuit.

2. The supply device according to claim 1, wherein said fuse element interrupts said series circuit as soon as a current through said series circuit exceeds a predetermined maximum current value.

3. The supply device according to claim 1, wherein said fuse element is purely passive.

4. The supply device according to claim 1, wherein said fuse element contains a fuse wire, which can be severed in an event of the short circuit.

5. The supply device according to claim 1, wherein said fuse element is a sacrificial element.

6. The supply device according to claim 1, wherein said fuse element is configured in such a way that said fuse element at least partly evaporates in an event of the short circuit.

7. The supply device according to claim 1, wherein said fuse element is integrated into said series resistor.

8. The supply device according to claim 1, wherein said at least one series resistor is a flat resistor.

9. The supply device according to claim 1, wherein said supply unit has a switching element that can be switched on and off.

10. The supply device according to claim 9, wherein said supply unit has an actuation unit, said switching element can be actuated in a pulse-like manner by means of said actuation unit.

11. The supply device according to claim 1, further comprising a first high-voltage-side connection terminal and a second high-voltage-side connection terminal configured for connecting to the energy store, said series circuit extends between said first high-voltage-side connection terminal and said second high-voltage-side connection terminal; wherein said series resistor is connected directly to said first high-voltage-side connection terminal; wherein said supply unit has a switched-mode power supply, with a switching element that can be switched on and off and a voltage tap, said switching element and said voltage tap are connected to one another in a series circuit, said switched-mode power supply has a first connection connected to said series resistor and a second connection connected to said second high-voltage-side connection terminal; and further comprising a first low-voltage-side connection terminal and a second low-voltage-side connection terminal disposed at said voltage tap for connection to the electrical assembly that is to be supplied with the electrical power.

12. The supply device according to claim 11, wherein said supply unit further has a resistance element disposed in parallel with said switching element or in parallel with said switched-mode power supply.

13. The supply device according to claim 1, further comprising a first high-voltage-side connection terminal and a second high-voltage-side connection terminal; wherein said series circuit extends between said first high-voltage-side connection terminal and said second high-voltage-side connection terminal, said first high-voltage-side connection terminal and said second high-voltage-side connection terminal are configured for connecting to the energy store; wherein said supply unit contains a variable resistor and a voltage tap in series with said variable resistor; and wherein said fuse element is disposed in series with said supply unit.

14. The supply device according to claim 1, wherein the supply device is dimensioned on an energy store side for a voltage of 1 kV to 20 kV.

15. The supply device according to claim 1, wherein the supply device is dimensioned on an output side for a voltage of 100 V to 1 kV.

16. A switching module for a modular multistage converter, the switching module comprising: power semiconductor switches; an energy store; a supply device connected in parallel with said energy store, said supply device containing: a series circuit composed of at least one series resistor and a supply unit, said series circuit connected to said energy store and said supply unit to be connected to an electrical assembly that is to be supplied with electrical power; and a fuse element, by means of said fuse element a short-circuit current through said supply unit can be electrically interrupted in an event of a short circuit.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0031] FIG. 1 is a schematic illustration of an exemplary embodiment of a switching module having a supply device according to the invention;

[0032] FIG. 2 is a schematic illustration of the exemplary embodiment of FIG. 1 in an event of a short circuit; and

[0033] FIG. 3 is a schematic illustration of a further exemplary embodiment of the supply device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0034] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a supply device 1 for a switching module 2 of a modular multistage converter. The switching module 2 is constructed in a half-bridge circuit. The switching module 2 thus contains a series circuit having a first power semiconductor switching unit 3 and a second power semiconductor switching unit 4, which each has a semiconductor switch 5 and a freewheeling diode 6. An energy store 7 in the form of a capacitor is arranged in parallel with the two power semiconductor switching units. The switching unit 2 is connected in a series circuit with further structurally identical switching units by the terminals 8 and 9 of the switching unit. During operation of the modular multistage converter, the switching module 2 is at a high-voltage potential that is usually not constant. A voltage Uc of approximately 3 kV is dropped across the energy store 7.

[0035] The supply device 1 contains a series circuit 10 composed of a series resistor 11 and a supply unit 12. The supply unit 12 contains a parallel circuit of a further resistance element 121 and a switching element 13. In the exemplary embodiment illustrated, the switching element 13 is an insulated-gate bipolar transistor (IGBT). The series circuit 10 is connected on the high-voltage side in a parallel circuit with the energy store 7.

[0036] In the exemplary embodiment illustrated, the supply unit 12 further has a voltage tap in the form of a medium-voltage capacitor 14. Low-voltage side connection terminals 15, 16 are arranged at the medium-voltage capacitor 14. Using the connection terminals 15, 16, the supply device 1 can be connected to the assembly that is to be supplied with power. During operation, a supply voltage Uv of 200 V is applied to the connection terminals 15, 16. If, depending on the assembly, a lower supply voltage, for example of 15 V, is also required, the connection terminals can be connected to a further power supply, which can transform the voltage from 200 V to 15 V.

[0037] The gate of the switching element 13 is connected to an actuation system 17. The opening and closing of the switching unit 13 is controlled by the actuation system 17. The actuation is carried out depending on the voltage dropped across the voltage tap 14. If the supply voltage Uv falls below a prescribed threshold value, the switching element 13 is switched on. If the prescribed threshold value is exceeded, the switching element 13 is closed. In this way, a pulse-like actuation of the switching element 13 is produced.

[0038] A fuse element 20a is arranged between the series resistor 11 and the supply unit 12. The fuse element 20a is provided to interrupt the series circuit 10 in the event of a fault. The fuse element 20a has a sacrificial element, which is designed in such a way that it evaporates when the series circuit 10 exceeds a current threshold value, wherein the electrical connection between the series resistor 11 and the supply unit 12 is isolated. Alternatively to or in combination with the fuse element 20a, the supply device has a fuse element 20b, which is arranged inside the supply unit 12. In the event of a fault, the fuse element 20b interrupts the short-circuit current through the faulty switching element 13. In the exemplary embodiment illustrated, the fuse elements 20a, 20b are of identical design.

[0039] FIG. 2 illustrates the supply device 1 and the switching module 2 of FIG. 1 in the event of a fault. The short circuit on account of a fault in the medium-voltage capacitor 14 or at the connection terminals 15, 16, the short circuit being indicated by the arrow 18, leads to a drop in the supply voltage Uv to zero. The actuation system 17 keeps the switching element 13 permanently open in this case. This in turn leads to a short-circuit current 19 through the series resistor 11 and can lead to thermal overloading of the series resistor.

[0040] The short-circuit current 19 is higher than the current threshold value of the fuse element 20a. In the fault event described, the fuse element 20a evaporates, which is indicated in FIG. 2 by a dashed line 21. The short-circuit current 19 is interrupted in this way before the thermal overloading of the series resistor 11 can lead to damage to the supply device 1 or the switching module 2. The fuse element 20b operates correspondingly.

[0041] FIG. 3 shows a supply device 1a. Identical and similar elements are in this case provided with identical reference signs in FIGS. 1 to 3.

[0042] A fuse element 20c is arranged in series with the supply unit 12. The design of the fuse element 20c corresponds to that of the fuse element 20a. A variable resistor 22 is arranged in series with the voltage tap 14. The variable resistor 22 can contain switch elements, such as semiconductor switches, by which the resistance value of the variable resistor 22 can be increased or decreased.

[0043] The switching module 2 can comprise a discharge resistor for the energy store, the discharge resistor being arranged in parallel with the energy store 7.