Medium frequency power generator

• US 7,692,936 B2
• Filed: 05/04/2007
• Issued: 04/06/2010
• Est. Priority Date: 05/05/2006
• Status: Expired due to Fees

• Current Assignee: Huettinger Elektronik GmbH + Company KG (TRUMPF SE + Co. KG)
• Original Assignee: Huettinger Elektronik GmbH + Company KG (TRUMPF SE + Co. KG)
• Inventors: Richter, Volkhard
• Primary Examiner(s): Riley; Shawn
• Application Number:
  US11/744,543
• Publication Number:
  US 20070258274A1
• Time in Patent Office: 1,068 Days
• Field of Search: 363/17, 363/132, 363/56.05
• US Class Current: 363/17
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02M 7/537 using semiconductor devices only, e.g. single switched pulse inverters
• CPC Class Codes: H05B 6/062 for cooking plates or the like

Abstract

An MF power generator includes a DC current supply connected to an inverter. The inverter includes at least one switching element connected to a first-polarity current supply potential, and an output network. Each switching element is provided with a decoupling circuit for decoupling the switching element from a voltage of the output network. This enables the low-loss switching of the switching elements.

Claims

1. An MF power generator for induction heating or a plasma process, the MF power generator comprising:

a DC current supply;

an inverter comprising at least one switching element connected to a first polarity current supply potential of the DC current supply; and

an output network connected to the inverter;

wherein the inverter comprises a decoupling circuit for each switching element for decoupling the switching element from a voltage of the output network;

wherein the decoupling circuit comprises;

a first component connected in series between the switching element and an input terminal of the output network; and

a second component connected between the switching element or the input terminal of the output network and a limiting potential differing from the first polarity current supply potential.

2. The MF power generator of claim 1, wherein the decoupling circuit comprises one or more of nonlinear components and active components.

3. The MF power generator of claim 1, wherein the output network includes an output oscillating circuit.

4. The MF power generator of claim 1, wherein the first component is designed as a diode, and the second component is designed as a freewheeling diode.

5. The MF power generator of claim 1, wherein the limiting potential is a second polarity current supply potential.

6. The MF power generator of claim 1, wherein the limiting potential is quantitatively larger than a second polarity current supply potential.

7. The MF power generator of claim 1, wherein the inverter comprises a relief circuit for each switching element.

8. The MF power generator of claim 7, wherein the relief circuit comprises one or more of nonlinear components and active components.

9. The MF power generator of claim 7, wherein the relief circuit includes a voltage rise delaying arrangement in parallel with the switching element.

10. The MF power generator of claim 9, wherein the voltage rise delaying arrangement includes a capacitor.

11. The MF power generator of claim 7, wherein the relief circuit comprises a first active component that is connected between the switching element to be relieved and the limiting potential or the second polarity current supply potential.

12. The MF power generator of claim 11, wherein the first active component includes a transistor.

13. The MF power generator of claim 7, wherein the relief circuit comprises a second active component that is connected between the switching element to be relieved and a reference potential.

14. The MF power generator of claim 13, wherein the second active component includes a transistor.

15. The MF power generator of claim 13, wherein the inverter comprises a network associated with the second active component.

16. The MF power generator of claim 1, wherein the DC current supply is designed as a mains rectifier or a PFC element.

17. The MF power generator of claim 1, wherein the inverter comprises a single switching element, a half-bridge with two switching elements, or a full bridge with four switching elements.

18. The MF power generator of claim 1, further comprising a controller connected to the switching elements to turn on the switching elements.

19. A method for controlling and/or regulating the power of an MF power generator comprising an inverter that includes at least one activatable switching element and an output network, the method comprising operating the switching element in a pulse width modulation method such that the switching element is at least largely decoupled from a voltage of the output network, in that a current direction reversal of the current between the switching element and the output network is prevented.

20. The method of claim 19, further comprising relieving the switching element during its switching processes by delaying the voltage rise at the switching element when the switching element is being opened.

21. The method of claim 19, further comprising relieving the switching element by reducing the voltage applied to it before the switching element is closed.

22. The method of claim 21, wherein relieving the switching element comprises relieving the switching element by reducing the voltage applied to it to about 0 V before the switching element is closed.

23. The method of claim 19, wherein the switching element is operated in the pulse group mode.

24. The method of claim 23, wherein the pulses in a pulse group have different lengths.

25. The method of claim 24, wherein the pulses at the beginning of a pulse group are longer than the ones at the end of the pulse group.