COST EFFECTIVE HYBRID PROTECTION FOR HIGH POWER AMPLIFIER

• US 20190312555A1
• Filed: 12/30/2016
• Published: 10/10/2019
• Est. Priority Date: 12/30/2016
• Status: Active Grant

• Current Assignee: Panasonic Holdings Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: Brindani, Franco, Roumpedaki, Natalia
• Granted Patent: US 11,804,807 B2
• Time in Patent Office: Days
• CPC Class Codes: H03F 1/52 Circuit arrangements for protecting such amplifiers monitoring arrangements G01R31/28; increasing reliability in communication systems, e.g. using redundancy H04B1/74
• CPC Class Codes: H05B 6/64 Heating using microwaves containers, packaging elements or packages specially adapted to be heated by microwaves B65D81/3446
• CPC Class Codes: H05B 6/681 Circuits comprising an inverter, a boost transformer and a magnetron
• CPC Class Codes: H05B 6/686 Circuits comprising a signal generator and power amplifier, e.g. using solid state oscillators
• CPC Class Codes: H05B 6/70 Feed lines
• CPC Class Codes: H05B 6/705 using microwave tuning
• CPC Class Codes: H05B 6/72 Radiators or antennas
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

An RF generation system is provided for an electromagnetic cooking device having a cavity. The system includes: a signal generator for generating an input RF signal; an RF feed configured to introduce electromagnetic radiation into the cavity and to receive reflected electromagnetic radiation from the cavity; and a high-power amplifier coupled between the signal generator and the RF feed. The high-power amplifier including an amplifying stage configured to output a signal that is amplified in power, and a circulator for directing the amplified output signal to the RF feed and for redirecting any reflected radiation received from the RF feed to a dummy load. The system further includes a hardware protection component for detecting backward power in the reflected radiation and for reducing power supplied to the amplifying stage if the backward power exceeds a power threshold within a time scale that prevents damage to the circulator.

Claims

1. A solid state radio frequency generation system for an electromagnetic cooking device having an enclosed cavity in which a food load is placed, the solid state radio frequency generation system comprising:

a small signal generator for generating an input RF signal;

an RF feed configured to introduce electromagnetic radiation into the enclosed cavity to heat up and prepare the food load, the RF feed configured to receive reflected electromagnetic radiation from the enclosed cavity;

a high-power RF amplifier coupled between the small signal generator and the RF feed, the high-power RF amplifier comprising;

at least one amplifying stage configured to output a signal that is amplified in power with respect to the input RF signal; and

a circulator for directing the amplified output signal to the RF feed and for redirecting any reflected waves and their associated power received from the RF feed to a dummy load; and

a hardware protection component for detecting backward power in the reflected electromagnetic radiation received by the RF feed and for reducing power supplied to the at least one amplifying stage if the backward power exceeds a power threshold within a time scale that prevents electrical stress or damage to the circulator.

2. The solid state radio frequency generation system of claim 1, wherein the time scale is shorter than a maximum capability of the circulator to sustain a power condition exceeding its maximum rating.

3. The solid state radio frequency generation system of claim 1, wherein the circulator has a maximum power rating of less than a maximum backward power to which the circulator could be exposed.

4. The solid state radio frequency generation system of claim 1, wherein the time scale is less than about 10 nanoseconds.

5. The solid state radio frequency generation system of claim 1, wherein the hardware protection component comprises a comparator for comparing the backward power to the power threshold, wherein the power threshold is adjustable.

6. The solid state radio frequency generation system of claim 5, wherein the hardware protection component further comprises a power control coupled to an output of the comparator for reducing the power supplied to the at least one amplifier stage when the output of the comparator represents that the backward power exceeds the power threshold.

7. The solid state radio frequency generation system of claim 6, wherein the power control reduces the power supplied to the at least one amplifier stage by interrupting the supply of power to the at least one amplifier stage.

8. A solid state radio frequency generation system for an electromagnetic cooking device having an enclosed cavity in which a food load is placed, the solid state radio frequency generation system comprising:

a small signal generator for generating an input RF signal;

a plurality of RF feeds configured to introduce electromagnetic radiation into the enclosed cavity to heat up and prepare the food load, the plurality of RF feeds each configured to receive reflected electromagnetic radiation from the enclosed cavity;

a set of high-power RF amplifiers coupled to the plurality of RF feeds, each high-power RF amplifier comprising;

at least one amplifying stage configured to output a signal that is amplified in power with respect to the input RF signal; and

a circulator for directing the amplified output signal to the RF feed and for redirecting any reflected waves and their associated power received from the RF feed to a dummy load; and

a hardware protection component for detecting backward power in the reflected electromagnetic radiation received by the plurality of RF feeds and for reducing power supplied to the plurality of high-power amplifiers if the backward power from any one of the plurality of RF feeds exceeds a power threshold within a time scale that prevents electrical stress or damage to the circulator of one of the plurality of high-power RF amplifiers.

9. The solid state radio frequency generation system of claim 8, wherein the time scale is shorter than a maximum capability of the circulator to sustain a power condition exceeding its maximum rating.

10. The solid state radio frequency generation system of claim 8, wherein the circulator of each of the plurality of high-power RF amplifiers has a maximum power rating of less than a maximum backward power to which the circulator could be exposed.

11. The solid state radio frequency generation system of claim 8, wherein the time scale is less than about 10 nanoseconds.

12. The solid state radio frequency generation system of claim 8, wherein the hardware protection component comprises a comparator for comparing the backward power to the power threshold, wherein the power threshold is adjustable.

13. The solid state radio frequency generation system of claim 12, wherein the hardware protection component further comprises a power control coupled to an output of the comparator for reducing the power supplied to each of the plurality of high-power RF amplifiers when the output of the comparator represents that the backward power exceeds the power threshold.

14. The solid state radio frequency generation system of claim 13, wherein the power control reduces the power supplied to each of the plurality of high-power RF amplifiers by interrupting the supply of power to each of the plurality of high-power RF amplifiers.

15. An electromagnetic cooking device comprising:

an enclosed cavity in which a food load is placed;

a small signal generator for generating an input RF signal;

an RF feed configured to introduce electromagnetic radiation into the enclosed cavity to heat up and prepare the food load, the RF feed configured to receive reflected electromagnetic radiation from the enclosed cavity;

a high-power RF amplifier coupled between the small signal generator and the RF feed, the high-power RF amplifier comprising;

at least one amplifying stage configured to output a signal that is amplified in power with respect to the input RF signal; and

a circulator for directing the amplified output signal to the RF feed and for redirecting any reflected waves and their associated power received from the RF feed to a dummy load; and

a hardware protection component for detecting backward power in the reflected electromagnetic radiation received by the RF feed and for reducing power supplied to the at least one amplifying stage if the backward power exceeds a power threshold within a time scale that prevents electrical stress or damage to the circulator.

16. The electromagnetic cooking device of claim 15, wherein the time scale is shorter than a maximum capability of the circulator to sustain a power condition exceeding its maximum rating.

17. The electromagnetic cooking device of claim 15, wherein the circulator has a maximum power rating of less than a maximum backward power to which the circulator could be exposed.

18. The electromagnetic cooking device of claim 15, wherein the time scale is less than about 10 nanoseconds.

19. The electromagnetic cooking device of claim 15, wherein the hardware protection component comprises a comparator for comparing the backward power to the power threshold, wherein the power threshold is adjustable.

20. The electromagnetic cooking device of claim 19, wherein the hardware protection component further comprises a power control coupled to an output of the comparator for reducing the power supplied to the at least one amplifier stage when the output of the comparator represents that the backward power exceeds the power threshold.