Control of heating elements

Patent metadata

Field	Value
Publication number	US-11190015-B2
Application number	US-201615561929-A
Country	US
Kind code	B2
Filing date	Mar 29, 2016
Priority date	Mar 30, 2015
Publication date	Nov 30, 2021
Grant date	Nov 30, 2021

Abstract

An apparatus for controlling one or more switched high power loads (or heating elements). The apparatus including: one or more switched high power loads (or heating elements), each high power load being powered from a common alternating current power source, and wherein each load is independently switched using a switching signal for zero crossing switching to achieve a desired average power output; the switching signal is generated that comprises a repeated switching sequence; the switching sequence indicates a respective selecting activation for each of the switched high power load over a sequence of half or full cycles.

First claim

We claim:

1. A kitchen appliance comprising:
a plurality of switched high power loads included in the kitchen appliance, each load being powered from a common alternating current power source;
a processor apparatus included in the kitchen appliance comprising:
(i) a memory having stored therein a lookup table; and
(ii) a processor adapted to generate a plurality of switching signals for controlling the plurality of loads, wherein the plurality of switching signals are generated based on a respective switching sequence retrieved from the lookup table, wherein each switching sequence is indicative of selective activation of the plurality of loads over a sequence of half or full cycles of the common alternating current power source, wherein a combination of the plurality of switching signals has no frequency components less than 24 Hz or frequency components above 24 Hz have more energy than any frequency components below 24 Hz; and

one or more zero crossing devices that are included in the kitchen appliance and that are electrically coupled with the plurality of loads and the processor apparatus, wherein the one or more zero crossing devices are configured to:
(i) receive the plurality of switching signals from the processor apparatus; and
(ii) independently switch each load using a respective switching signal of the plurality of switching signals for zero crossing switching to achieve a desired average power output.

2. The kitchen appliance according to claim 1 , wherein the plurality of loads are powered from the common alternating current power source operating at 60 Hz, wherein the plurality of loads are repeatedly switched according to the respective switching sequence in 5 or less half cycles of common alternating current power source.

3. The kitchen appliance according to claim 1 , wherein the one or more zero crossing devices are configured to perform zero-crossing switching of the plurality of loads to achieve asymmetric power consumption between the plurality of loads.

4. The kitchen appliance according to claim 1 , further comprising a temperature sensor electrically coupled with the processor apparatus, wherein the processor apparatus is configured to generate the plurality of switching signals based on a temperature feedback signal indicative of a current temperature of the plurality of loads received from the temperature sensor.

5. A method of generating one or more switching signals that control operation of a plurality of switched high power loads in a kitchen appliance, each load being powered from a common alternating current power source, wherein the method comprises:
generating, by a processor apparatus of the kitchen appliance, a plurality of switching signals for controlling the plurality of loads of the kitchen appliance, wherein the plurality of switching signals are generated based on a respective switching sequence retrieved from a lookup table stored in memory of the processor apparatus, wherein each switching sequence is indicative of a respective selective activation of the plurality of loads over a sequence of half or full cycles, wherein each switching sequence is indicative of a selective activation of the plurality of loads over a sequence of half or full cycles of the common alternating current power source, wherein a combination of the plurality of switching signals has no frequency components less than 24 Hz or frequency components above 24 Hz have more energy than any frequency components below 24 Hz; and
receiving, from the processor apparatus by one or more zero crossing devices of the kitchen appliance in electrical communication with the plurality of loads, the plurality of switching signals; and
independently switching, by the one or more zero crossing devices of the kitchen appliance, each load of the kitchen appliance using a respective switching signal of the plurality of switching signals for zero crossing switching to achieve a desired average power output.

6. The kitchen appliance according to claim 1 , wherein the one or more zero crossing devices comprise of:
one or more zero crossing switches; or
one or more zero crossing circuits.

7. The kitchen appliance according to claim 1 , wherein the plurality of loads comprise of a plurality of heater devices.

8. The kitchen appliance according to claim 1 , wherein the kitchen appliance is one of:
an oven; or
a toaster.

9. The kitchen appliance according to claim 1 , further comprising:
a temperature sensor to sense a temperature of the plurality of loads;
a temperature controller electrically coupled to the one or more zero crossing devices, the plurality of loads and the temperature sensor, wherein the temperature controller is configured to:
receive, from the temperature sensor, a temperature feedback signal indicative of a current temperature of the plurality of loads; and
electrically connect or disconnect the one or more zero crossing devices and the plurality of loads based on a comparison of the current temperature with a temperature set point.

10. The kitchen appliance according to claim 9 , wherein the temperature controller is configured to electrically connect the one or more zero crossing devices with the plurality of loads in response to the current temperature being below the temperature set point.

11. The kitchen appliance according to claim 9 , wherein the temperature controller is configured to electrically disconnect the one or more zero crossing devices from the plurality of loads in response to the current temperature being above the temperature set point.

12. The kitchen appliance according to claim 9 , wherein the temperature controller is configured to receive a signal indicative of the temperature set point.

13. The kitchen appliance according to claim 4 , wherein the processor apparatus is configured to receive a temperature set point signal indicative of a temperature set point, wherein the processor apparatus is configured to generate the plurality of switching signals based on a comparison of the current temperature to the set point temperature.

14. The method according to claim 5 , wherein the plurality of loads are powered from the common alternating current power source operating at 60 Hz, wherein the method includes repeatedly switching the plurality of loads according to the respective switching sequence in 5 or less half cycles of common alternating current power source.

15. The method according to claim 5 , wherein the method includes the one or more zero crossing devices performing zero-crossing switching of the plurality of loads to achieve asymmetric power consumption between the plurality of loads.

16. The method according to claim 5 , further comprising generating, by the processor apparatus of the kitchen appliance, the plurality of switching signals based on a temperature feedback signal indicative of a current temperature of the plurality of loads of the kitchen appliance received from a temperature sensor electrically coupled to the processor apparatus.

17. The method according to claim 5 , wherein the kitchen appliance comprises a temperature sensor to sense a temperature of the plurality of loads, and a temperature controller electrically coupled to the one or more zero crossing devices, the plurality of loads and the temperature sensor, wherein the method includes:
receiving, at the temperature controller from the temperature sensor, a temperature feedback signal indicative of a current temperature of the plurality of loads; and
electrically connect or disconnect the one or more zero crossing devices and the plurality of loa

Assignees

• Breville R & D Pty Ltd

Inventors

• Marsh-Croft Ashley
• Hegedis Tibor
• Foxlee Brendan John
• Craig Emma
• Meng Lichan

Classifications

• H02J2105/42

  Home appliances · CPC title

• H02J3/002

  Flicker reduction, e.g. compensation of flicker introduced by non-linear load · CPC title

• H02M5/2573 Primary

  with control circuit · CPC title

• G05F1/02

  Regulating electric characteristics of arcs · CPC title

• H02M5/257

  using semiconductor devices only · CPC title