THYRISTOR RECTIFIER WITH IMPROVED SURGE CHARACTERISTICS AND ELECTRIC MOTOR DRIVE WITH A CORRESPONDING THYRISTOR RECTIFIER

Abstract

The present invention relates to AC-DC conversion in power electronics. In particular, the present invention is directed at a thyristor rectifier, which may be employed in an electric motor drive. The rectifier includes three thyristors and three diodes, wherein the thyristors are connected to a positive rectifier output and the three diodes are connected to a negative rectifier output. The present invention also relates to an electric motor drive comprising a corresponding thyristor rectifier. In general, the present invention may be used in a frequency converter for an electric motor drive, but it can also be used in non-drive application.

Claims

1. A thyristor rectifier, in particular for an electric motor drive, comprising three thyristors and three diodes, wherein the thyristors are connected to a positive rectifier output and the three diodes are connected to a negative rectifier output, wherein the thyristor rectifier comprises an impedance and a capacitor arranged in series to each other, wherein the capacitor 12 connects to the positive rectifier output and the impedance 11 connects to the negative rectifier output and wherein the impedance is a NTC-resistor.

2. The thyristor rectifier according to claim 1, wherein the impedance is directly connected to the negative rectifier output.

3. The thyristor rectifier according to claim 1, wherein the capacitor is directly connected to the positive rectifier output.

4. The thyristor rectifier according to claim 1, wherein a circuit portion comprising the impedance and the capacitor is arranged in parallel to one circuit portion comprising at least a second impedance, said second impedance connecting the positive rectifier output to the negative rectifier output.

5. The thyristor rectifier according to claim 1, wherein the thyristors are directly connected to a positive rectifier output and the three diodes are directly connected to a negative rectifier output.

6. An electric motor drive comprising a thyristor rectifier according to claim 1.

7. The thyristor rectifier according to claim 2, wherein the capacitor is directly connected to the positive rectifier output.

8. The thyristor rectifier according to claim 2, wherein a circuit portion comprising the impedance and the capacitor is arranged in parallel to one circuit portion comprising at least a second impedance, said second impedance connecting the positive rectifier output to the negative rectifier output.

9. The thyristor rectifier according to claim 3, wherein a circuit portion comprising the impedance and the capacitor is arranged in parallel to one circuit portion comprising at least a second impedance, said second impedance connecting the positive rectifier output to the negative rectifier output.

10. The thyristor rectifier according to claim 2, wherein the thyristors are directly connected to a positive rectifier output and the three diodes are directly connected to a negative rectifier output.

11. The thyristor rectifier according to claim 3, wherein the thyristors are directly connected to a positive rectifier output and the three diodes are directly connected to a negative rectifier output.

12. The thyristor rectifier according to claim 4, wherein the thyristors are directly connected to a positive rectifier output and the three diodes are directly connected to a negative rectifier output.

13. An electric motor drive comprising a thyristor rectifier according to claim 2.

14. An electric motor drive comprising a thyristor rectifier according to claim 3.

15. An electric motor drive comprising a thyristor rectifier according to claim 4.

16. An electric motor drive comprising a thyristor rectifier according to claim 5.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0015] Further details and advantages of the invention are described with reference to the embodiment shown in FIG. 1.

DETAILED DESCRIPTION

[0016] FIG. 1 shows a schematic view of a thyristor rectifier 10. The thyristor rectifier 10 may be a part of an electric motor drive. The thyristor rectifier 10 comprises three thyristors D1, D3, D5 and three diodes D2, D4, D6, wherein the thyristors D1, D3, D5 are connected to a positive rectifier output REC+ and the three diodes D2, D4, D6 are connected to a negative rectifier output REC−. According to the invention, the thyristor rectifier 10 comprises an impedance 11 and a capacitor 12 arranged in series to each other, wherein the capacitor 12 connects to the positive rectifier output REC+ and the impedance 11 connects to the negative rectifier output REC− and wherein the impedance is a NTC-resistor.

[0017] The circuit portion comprising the impedance 11 and the capacitor 12 is arranged in parallel to one circuit portion comprising at least a second impedances 13, said second impedances 13 connecting the positive rectifier output REC+ to the negative rectifier output REC−. In addition, the thyristors D1, D3, D5 are directly connected to the positive rectifier output REC+ and the three diodes D2, D4, D6 are directly connected to the negative rectifier output REC−.

[0018] Although not shown in FIG. 1, the presently described thyristor rectifier may be part of an electric motor drive.

[0019] The invention is not limited to one of the above-described embodiments, but can be modified in many ways.

[0020] All of the features and advantages arising from the claims, the description and the drawings, including constructive details, spatial arrangements and procedural steps, can be essential to the invention both individually and in the most varied of combinations.