INVERTER WITH LESS SNUBBER CAPACITORS

• US 20150003132A1
• Filed: 01/08/2013
• Published: 01/01/2015
• Est. Priority Date: 01/12/2012
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Woywode, Oliver, Luerkens, Peter
• Application Number:
  US14/371,775
• Publication Number:
  US 20150003132A1
• Time in Patent Office: Days
• US Class Current: 363/132
• CPC Class Codes: H02M 1/346 Passive non-dissipative snubbers
• CPC Class Codes: H02M 1/348 Passive dissipative snubbers
• CPC Class Codes: H02M 7/483 Converters with outputs that each can have more than two voltages levels
• CPC Class Codes: H02M 7/487 Neutral point clamped inverters
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An electrical inverter 18 for transforming an DC current into an AC current comprises at least one half-bridge 54. The half bridge 54 comprises at least two series connected semiconductor switches 58a, 58b, 58c, 58d inter-connecting an input terminal 54, 56 with an output terminal 50 of the inverter 18. A snubber capacitor 62a, 62b is connected in parallel to at least two semiconductor switches 58a, 58b, 58c, 58d of the half bridge 54.

Claims

1. An electrical inverter for transforming an DC current into an AC current,

the inverter comprising at least one half-bridge;

the half bridge comprising at least two series connected semiconductor switches interconnecting an input terminal with an output terminal of the inverter

wherein a snubber capacitor is connected in parallel to the at least two series connected semiconductor switches of the half bridge;

wherein a neutral point terminal is connected via a diode to a connection between the at least two series connected semiconductor switches of the half bridge;

wherein the connection between the at least two semiconductor switches is not directly connected to the snubber capacitor.

3. The electrical inverter of claim 1,

wherein the snubber capacitor is directly connected to the input terminal and to the output terminal.

4. The electrical inverter of claim 1,

wherein the snubber capacitor is connected in parallel to two semiconductor switches.

5. The electrical inverter of claim 1,

wherein the half bridge interconnects a positive input terminal with a negative input terminal and the half bridge comprises at least two upper series connected semiconductor switches interconnecting the positive terminal with an output terminal and at least two lower series connected semiconductor switches interconnecting the negative terminal with the output terminal,

wherein a neutral point terminal is connected between the at least two upper semiconductor switches and between the at least two lower semiconductor switches by means of diodes;

wherein an upper snubber capacitor is connected in parallel to the at least two upper semiconductor switches;

wherein a lower snubber capacitor is connected in parallel to the at least two lower semiconductor switches.

6. The electrical inverter of claim 1,

wherein the half-bridge has only two snubber capacitors.

7. The electrical inverter of claim 1,

wherein the electrical inverter has at most half as much snubber capacitors as semiconductor switches.

8. The electrical inverter of claim 1,

wherein the inverter comprises two half bridges;

wherein the electrical inverter is a 5-level inverter adapted to generate a negative full voltage (−

2V_DC) and a positive full voltage (+2V_DC), a negative half voltage (−

V_DC) and a positive half voltage (−

V_DC) and no voltage (0 V) between two output terminals as output voltage.

9. A method for switching an electrical inverter according to claim 1, the method comprising the step of:

switching semiconductor switches in the half bridge in such a way that a voltage change at the output terminal of the half bridge is generated that has an opposite direction with respect to a sign of a current flowing from the output terminal to a load.

10. A computer program for controlling an electrical inverter, which, when being executed by a processor, is adapted to carry out the steps of the method of claim 9.

12. A high voltage device, for example an X-ray device, comprising:

an input rectifier for rectifying an input voltage into an DC voltage;

an electrical inverter according to claim 1 for converting the DC voltage into an AC output voltage;

an inductive load for receiving the output voltage of the inverter.

13. The high voltage device of claim 12, further comprising:

a controller adapted for executing the method for switching an electrical inverter.

2. (canceled)

11. A computer-readable medium, in which a computer program according to claim 11 is stored.