Power delivery system for an induction cooktop with multi-output inverters

• US 10,660,162 B2
• Filed: 03/16/2017
• Issued: 05/19/2020
• Est. Priority Date: 03/16/2017
• Status: Active Grant

• Current Assignee: Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: Calesella, Carlo, Parachini, Davide, Pastore, Cristiano Vito
• Primary Examiner(s): Ross, Dana
• Assistant Examiner(s): Mills, Jr., Joe E
• Application Number:
  US15/460,705
• Publication Number:
  US 20180270914A1
• Time in Patent Office: 1,160 Days
• Field of Search: 219620
• CPC Class Codes: H05B 6/065 using coordinated control of multiple induction coils

Abstract

A power delivery system and method for an induction cooktop are provided herein. A plurality of inverters are each configured to apply an output power to a plurality of induction coils electrically coupled thereto via corresponding relays. A selected inverter is operable to momentarily idle to enable commutation of a relay connected thereto. An active inverter is operable to increase its output power for the duration in which the selected inverter is idled in order to lessen power fluctuations experienced on a mains line.

Claims

1. A power delivery system for an induction cooktop, comprising:

a plurality of inverters, each of which is configured to apply an output power to a plurality of induction coils electrically coupled thereto via corresponding relays;

a controller configured to;

control a selected inverter to momentarily enter an idle state;

in response to the idle state, control a commutation of a relay connected thereto; and

control an active inverter to increase an output power for the duration in which the selected inverter is in the idle state, thereby decreasing power fluctuations on a mains line.

2. The power delivery system of claim 1, wherein the controller is further configured to:

increase the output power applied to each of a plurality of active induction coils associated with the active inverter.

3. The power delivery system of claim 1, wherein during the idling of the selected inverter, the controller is configured to increase the output power of the active inverter by an additional output power that is based on a pre-idle output power of the selected inverter.

4. The power delivery system of claim 3, wherein the additional output power is equal to the pre-idle output power of the selected inverter that is applied to at least one associated induction coil that was active before and remains active after the idling of the selected inverter.

5. The power delivery system of claim 3, wherein the additional output power is less than the pre-idle output power of the selected inverter that is applied to at least one associated induction coil that was active before and remains active after the idling of the selected inverter.

6. The power delivery system of claim 3, wherein the controller is further configured to:

decrease the output power of the active inverter over the course of a control period, thereby offsetting the additional power applied during the idling of the selected inverter.

7. The power delivery system of claim 1, wherein the duration in which the selected inverter is idled is set equal to an integer number of mains half-cycles of a mains voltage supplied to the induction cooktop and is synchronized with a mains voltage zero crossings.

20. The power delivery system accordingly to claim 1, wherein the duration in which the selected inverter is in the idle state corresponds to a predetermined number of mains half-cycles of a mains voltage supplied to the induction cooktop.

8. An induction cooktop comprising:

a plurality of induction coils;

a plurality of relays, each of which is connected to a corresponding induction coil;

a plurality of inverters, each of which is connected to more than one relay and configured to apply an output power to the corresponding induction coils;

a controller configured to;

control at least one selected inverter to momentarily idle and enable a commutation of a relay connected thereto, wherein the timing in which the at least one selected inverter is idled is synchronized with a mains voltage zero crossing of a mains voltage supplied to the induction cooktop; and

control at least one active inverter to increase an output power for the duration in which the at least one selected inverter is idled decreasing power fluctuations experienced on the mains line.

9. The induction cooktop of claim 8, wherein the increased output power of the at least one active inverter is applied to all active induction coils associated therewith.

10. The induction cooktop of claim 8, wherein during the idling of the at least one selected inverter, the controller is configured to increase the output power of the at least one active inverter by an additional output power that is based on a pre-idle output power of the at least one selected inverter.

11. The induction cooktop of claim 10, wherein the additional output power is equal to the pre-idle output power of the at least one selected inverter that is applied to at least one associated induction coil that was active before and remains active after the idling of the at least one selected inverter.

12. The induction cooktop of claim 10, wherein the additional output power is less than the pre-idle output power of the at least one selected inverter that is applied to at least one associated induction coil that was active before and remains active after the idling of the at least one selected inverter.

13. The induction cooktop of claim 10, wherein the at least one active inverter decreases its output power over the course of a control period to offset the additional power applied during the idling of the at least one selected inverter.

14. The induction cooktop of claim 8, wherein the duration in which the at least one selected inverter is idled is set equal to an integer number of mains half-cycles.

15. A power delivery method for an induction cooktop, comprising the steps of:

providing a plurality of inverters, each of which is configured to apply an output power to a plurality of induction coils electrically coupled thereto via corresponding relays;

momentarily idling a selected inverter to enable commutation of a relay connected thereto; and

increasing an output power of an active inverter for the duration in which the selected inverter is idled, thereby decreasing power fluctuations experienced on a mains line.

16. The power delivery method of claim 15, wherein the increased output power of the active inverter is applied to all active induction coils associated therewith.

17. The power delivery method of claim 15, wherein, during the idling of the selected inverter, the output power of the active inverter is increased by an additional output power that is based on a pre-idle output power of the selected inverter.

18. The power delivery method of claim 17, wherein the additional output power is equal to or less than the pre-idle output power of the selected inverter that is applied to at least one associated induction coil that was active before and remains active after the idling of the selected inverter.

19. The power delivery method of claim 17, further comprising the step of decreasing the output power of the active inverter over the course of a control period to offset the additional power applied during the idling of the selected inverter.