Method for operating a resonant converter, and resonant converter

Patent metadata

Field	Value
Publication number	US-9455638-B2
Application number	US-201514624121-A
Country	US
Kind code	B2
Filing date	Feb 17, 2015
Priority date	Feb 18, 2014
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

A method for operating a resonant converter having an inverter circuit, the inverter circuit having a plurality of switches, includes: switching each of the switches of the plurality of switches at an actuation frequency and with a phase angle offset relative to one another, such that a voltage of an output of the inverter circuit has a duty factor; and determining the actuation frequency and the duty factor for a prescribable operating point and with a prescribable phase reserve of the resonant converter. A resonant converter and an x-ray generator having a resonant converter are described.

First claim

The invention claimed is:

1. A method for operating a resonant converter, the resonant converter comprising an inverter circuit, the inverter circuit comprising a plurality of switches, the method comprising:
switching each of the switches of the plurality of switches at an actuation frequency and with a phase shift relative to each other, such that a voltage at an output of the inverter circuit has a duty factor,
wherein the plurality of switches comprises a first switch, a second switch, a third switch, and a fourth switch, wherein the first switch and the second switch form a first bridge path, and wherein the third switch and the fourth switch form a second bridge path; and
determining the actuation frequency and the duty factor for an assignable operating point and with an assignable phase reserve of the resonant converter,
wherein a latching time is smaller than the phase reserve divided by 2π times the actuation frequency, wherein the latching time indicates a period of time between switching of the first switch and the second switch and between switching of the third switch and the fourth switch.

2. The method of claim 1 , wherein the phase reserve indicates a phase angle offset between disconnection of the plurality of switches and a zero crossing of a resonant circuit current.

3. The method of claim 2 , wherein
the method further comprises:
switching the first switch, the second switch, the third switch, and the fourth switch at the actuation frequency;
switching the first switch and the second switch in alternation;
switching the third switch and the fourth switch in alternation; and
switching the first switch and the second switch of the first bridge path and the third switch and the fourth switch of the second bridge path with a phase angle offset relative to one another, such that the output of the inverter circuit provides a voltage having the duty factor.

4. The method of claim 3 , wherein the phase reserve indicates the phase angle offset that exists between either (a) disconnection of the first switch and a zero crossing of a resonant circuit current and between disconnection of the second switch and the zero crossing of the resonant circuit current, or (b) disconnection of the third switch and the zero crossing of the resonant circuit current and between disconnection of the fourth switch and the zero crossing of the resonant circuit current.

5. The method of claim 2 , wherein an input voltage of the resonant converter, an output voltage of the resonant converter, and an output current of the resonant converter stipulate the operating point.

6. The method of claim 2 , further comprising determining the duty factor and the actuation frequency from stored, previously determined tables based on the operating point.

7. The method of claim 1 , wherein
the method further comprises:
switching the first switch, the second switch, the third switch, and the fourth switch at the actuation frequency;
switching the first switch and the second switch in alternation;
switching the third switch and the fourth switch in alternation; and
switching the first switch and the second switch of the first bridge path and the third switch and the fourth switch of the second bridge path with a phase angle offset relative to one another, such that the output of the inverter circuit provides a voltage having the duty factor.

8. The method of claim 7 , wherein the phase reserve indicates the phase angle offset that exists between either (a) disconnection of the first switch and a zero crossing of a resonant circuit current and between disconnection of the second switch and the zero crossing of the resonant circuit current, or (b) disconnection of the third switch and the zero crossing of the resonant circuit current and between disconnection of the fourth switch and the zero crossing of the resonant circuit current.

9. The method of claim 8 , wherein an input voltage of the resonant converter, an output voltage of the resonant converter, and an output current of the resonant converter stipulate the operating point.

10. The method of claim 8 , wherein an input voltage of the resonant converter, an output voltage of the resonant converter, and an output current of the resonant converter stipulate the operating point.

11. The method of claim 7 , wherein an input voltage of the resonant converter, an output voltage of the resonant converter, and an output current of the resonant converter stipulate the operating point.

12. The method of claim 1 , wherein an input voltage of the resonant converter, an output voltage of the resonant converter, and an output current of the resonant converter stipulate the operating point.

13. The method of claim 1 , further comprising determining the duty factor and the actuation frequency from stored, previously determined tables based on the operating point.

14. The method of claim 1 , further comprising:
using a control unit to comply dynamically with the phase reserve based on limitation, pilot control, regulation of the actuation frequency, regulation of the duty factor, or combinations thereof.

15. The method of claim 1 , wherein the phase reserve is complied with dynamically by observation of a resonant circuit current.

16. A resonant converter comprising an inverter circuit, the inverter circuit comprising a plurality of switches, wherein the resonant converter is configured to:
switch each of the switches of the plurality of switches of the inverter circuit at an actuation frequency and with a phase shift relative to each other, such that a voltage at an output of the inverter circuit has a duty factor,
wherein the plurality of switches comprises a first switch, a second switch, a third switch, and a fourth switch, wherein the first switch and the second switch form a first bridge path, and wherein the third switch and the fourth switch form a second bridge path; and
determine the actuation frequency and the duty factor for an assignable operating point and with an assignable phase reserve of the resonant converter,
wherein a latching time is smaller than the phase reserve divided by 2π times the actuation frequency, wherein the latching time indicates a period of time between switching of the first switch and the second switch and between switching of the third switch and the fourth switch.

17. The resonant converter of claim 16 , further comprising:
a regulatory device configured to use previously determined and stored tables to determine the actuation frequency and the duty factor from the operating point and the phase reserve.

18. An x-ray generator comprising a resonant converter, the resonant converter comprising an inverter circuit, the inverter circuit comprising a plurality of switches, wherein the resonant converter is configured to:
switch each of the switches of the plurality of switches of the inverter circuit at an actuation frequency and with a phase shift relative to each other, such that a voltage at an output of the inverter circuit has a duty factor,
wherein the plurality of switches comprises a first switch, a second switch, a third switch, and a fourth switch, wherein the first switch and the second switch form a first bridge path, and wherein the third switch and the fourth switch form a second bridge path; and
determine the actuation frequency and the duty factor for an assignable operating point and with an assignable phase reserve of the resonant converter,
wherein a latching time is smaller than the phase reserve divided by 2π times the actuation frequency, wherein the latching time

Assignees

• Waffler Stefan
• Siemens Ag

Inventors

• Waffler Stefan

Classifications

• H05G1/10

  Power supply arrangements for feeding the X-ray tube {(supply circuits with converters in general H02M; supply circuits for emitters and amplifiers H04B1/16 - H04B1/1623)} · CPC title

• H01J35/025

  X-ray tubes with structurally associated circuit elements · CPC title

• H02M3/33507 Primary

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02M2001/0064

  Electricity · mapped topic

• Y02B70/1433

  Cross-Sectional Technologies · mapped topic