Induction generator for induction heating devices and a method for the operation of an induction generator for induction heating elements

Patent metadata

Field	Value
Publication number	US-9572202-B2
Application number	US-201214236058-A
Country	US
Kind code	B2
Filing date	Sep 12, 2012
Priority date	Sep 15, 2011
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

An induction generator is connected to a three-phase mains. The induction generator includes a control unit ( 10 ) connected to a current transformer ( 38 ), on one (L 1 ) of the lines (L 1 , L 2 , L 3 ) of the three-phase mains. The induction generator includes a number of power sections ( 26, 28, 30, 32, 34, 36 ). Each power section ( 26, 28, 30, 32, 34, 36 ) supplies one of the induction coils ( 40, 42, 44, 46, 48, 50 ). A control unit ( 10 ) estimates and corrects harmonic distortions of the mains current via the current transformer ( 38 ). The power transferred to a heated object as a function of the frequency is stored in a memory of the control unit ( 10 ), so that the heated object is identifiable by its frequency-power characteristic. The frequency spectrum of the transferred power related to a harmonic distortion in the line (L 1 ) is stored in the memory ( 10 ) if the distortion exceeds a predetermined limit. The harmonic distortions are corrected by the control unit ( 10 ) if a heated object with the frequency-power characteristic related to the harmonic distortion is detected.

First claim

The invention claimed is:

1. An induction generator for for induction coils of a cooking hob, wherein:
the induction generator is connected or connectable to different lines (LI, L 2 , L 3 ) of a three-phase mains,
the induction generator includes a control unit ( 10 ) connected to a current transformer ( 38 ) placed on one line (LI) of the three-phase mains,
the induction generator includes a number of power sections ( 26 , 28 , 30 , 32 , 34 , 36 ),
each power section ( 26 , 28 , 30 , 32 , 34 , 36 ) is provided for supplying one of the induction heating elements ( 40 , 42 , 44 , 46 , 48 , 50 ),
the control unit ( 10 ) is provided for estimating via the current transformer ( 38 ) and correcting harmonic distortions of the mains current,
the power transferred to a heated object as a function of the frequency is stored or storable in a memory of the control unit ( 10 ), so that the heated object is identifiable by its frequency-power characteristic,
the frequency spectrum of the transferred power related to an harmonic distortion in the line (LI) supplying the control unit is stored or storable in the memory of the control unit ( 10 ), if said harmonic distortion exceeds a predetermined limit,
and the harmonic distortions of the mains current are corrected or correctable by the control unit ( 10 ), if the heated object with the frequency-power characteristic related to the harmonic distortion is detected.

2. The induction generator according to claim 1 , wherein the induction generator includes a number of detection devices ( 14 , 16 , 18 ), wherein each detection device ( 14 , 16 , 18 ) is connected to or associated with one line (LI, L 2 , L 3 ) of the three-phase mains.

3. The induction generator according to claim 1 , wherein the induction generator includes a number of rectifiers ( 20 , 22 , 24 ), wherein each rectifier ( 20 , 22 , 24 ) is connected to or associated with one line (LI, L 2 , L 3 ) of the three-phase mains.

4. The induction generator according to claim 1 , wherein the control unit ( 10 ) is directly connected to that detection device ( 14 ) and those power sections ( 26 , 28 ) associated with the line (LI) supplying the control unit ( 10 ).

5. The induction generator according to claim 1 , wherein the control unit ( 10 ) is connected via galvanic insulation means ( 52 ) to those detection devices ( 16 , 18 ) and power sections ( 30 , 32 , 34 , 36 ) associated with those lines (L 2 , L 3 ) of the three-phase mains, which are not supplying the control unit ( 10 ).

6. The induction generator according to claim 1 , wherein the power transferred to the heated object as a function of the frequency is stored or storable as a table in the memory of the control unit ( 10 ).

7. The induction generator according to claim 1 , wherein the heated object is a pot or a pan heated by the induction coils.

8. A method for operating an induction generator for induction coils of a cooking hob, said induction generator is connected to different lines (LI, L 2 , L 3 ) of a three-phase mains and includes a control unit ( 10 ) supplied by one line (LI) of the three-phase mains via a power supply, said control unit ( 10 ) is connected to a current transformer ( 38 ) in order to detect the current of the one line (LI) of the three-phase mains, and a number of power sections ( 26 , 28 , 30 , 32 , 34 , 36 ), each power section ( 26 , 28 , 30 , 32 , 34 , 36 ) is provided for supplying one of the induction heating elements ( 40 , 42 , 44 , 46 , 48 , 50 ), wherein the method comprises the steps of:
estimating harmonic distortions of the mains current by the control unit ( 10 ) via the current transformer ( 38 ),
storing the power transferred to a heated object as a function of the frequency in a memory of the control unit ( 10 ), so that the heated object is identifiable by its frequency spectrum,
storing the frequency spectrum of the transferred power related to an harmonic distortion in the line (LI) supplying the control unit in the memory of the control unit ( 10 ), if said harmonic distortion exceeds a predetermined limit, and
correcting the harmonic distortions of the mains current by the control unit ( 10 ), if the heated object with the frequency spectrum related to the harmonic distortion is detected.

9. The method according to claim 8 , wherein the current of each line (LI, L 2 , L 3 ) of the three-phase mains is detected by a separate detection device ( 14 , 16 , 18 ) in each case.

10. The method according to claim 8 , wherein the current of each line (LI, L 2 , L 3 ) of the three-phase mains is rectified by a separate rectifier ( 20 , 22 , 24 ) in each case.

11. The method according to claim 8 , wherein the power transferred to the heated object as a function of the frequency is stored as a table in the memory of the control unit ( 10 ).

12. The method according to claim 8 , wherein the heated object is a pot or a pan heated by the induction coils.

13. An induction cooking hob with a number of induction coils, wherein the induction cooking hob comprises at least one induction generator according to claim 1 .

Assignees

• Viroli Alex
• Rossi Andrea
• Jeanneteau Laurent
• Zannoni Luca
• Electrolux Home Products Corp Nv

Inventors

• Viroli Alex
• Rossi Andrea
• Jeanneteau Laurent
• Zannoni Luca

Classifications

• H05B6/062 Primary

  for cooking plates or the like · CPC title

• H05B2213/05

  Heating plates with pan detection means · CPC title

• H05B6/065 Primary

  using coordinated control of multiple induction coils · CPC title