Induction hob and method of operating same

Abstract

A method of operating an induction hob, the induction hob comprising at least one induction coil for heating a cookware, the method comprises the steps of: receiving a high power user command indicative of a high power level to be provided to the cookware during cooking, controlling an induction coil to adjust an increase in heating power provided to the cookware from a low heating power level to the high power level, the method comprising the steps of: receiving a silent mode command, the silent mode command indicates a request to reduce acoustic noise generated by the cooker when heated by the induction hob; measuring the temperature of the induction coil; measuring a time elapsed from receiving the high power user command; an increase in heating power from a low heating power level to a high heating power level is delayed until a first condition or a second condition is satisfied.

Description

Technical Field

[0001] The present invention generally relates to the technical field of induction cooktops. More particularly, the present invention relates to reducing the acoustic noise generated by cookware when heated by an induction cooktop. Background Art

[0002] Induction cooktops for preparing food are well known in the art. Typically, an induction cooktop includes a heating zone associated with an induction coil. To heat cookware placed on the heating zone, the induction coil is electrically coupled to an electronic drive unit that drives alternating current through the induction coil.

[0003] The alternating current generates a time-varying magnetic field. The magnetic field generated by the induction coil induces eddy currents that circulate in the cookware due to inductive coupling between the induction coil and the cookware piece placed above the induction coil.

[0004] The presence of eddy currents generates heat within the cookware element due to the electrical resistance of the cookware element.

[0005] It is also known that pots and cookware generally generate acoustic noise when heated by an induction cooktop. The acoustic noise generated by the cookware depends largely on its structure and construction and tends to be higher in the case of lightweight cookware or multi-layer materials (e.g. stainless steel with an aluminum core).

[0006] At the start of a cooking cycle, there's a temperature difference between the outer and inner layers of the cookware. The outer layer is heated immediately by the induction cooktop, while the inner layer heats up through conduction. Consequently, the intensity of the noise generated by the cookware depends largely on the heating power supplied to the cookware.

[0007] When heated by high heating powers, the cookware produces acoustic resonances at frequencies within the frequency range of human hearing, which can be disturbing to the cooktop user.

[0008] In order to solve the technical problem of acoustic noise interference, many solutions have been proposed.

[0009] Some known solutions are disclosed in, for example, CN000114263943A, JP002003257610A, JP002007323886A, JP002009301915A, US020030164373A1 and CN000109140543A.

[0010] In detail, the solution disclosed in CN000109140543A relates to a noise reduction method, which basically includes the following steps: determining whether the temperature of the cooker is higher than a first predetermined temperature; when the temperature of the cooker is lower than the first preset temperature, controlling the induction cooker to heat the cooker at a first heating power; when the temperature of the cooker is higher than the first preset temperature, controlling the induction cooker to heat the cooker at a second heating power higher than the first heating power.

[0011] The solution disclosed in CN000109140543A requires the presence of a temperature sensor system, which, according to different embodiments, can be arranged in the handle of the cooker, wherein a communication system is provided to transmit the measured temperature to the control panel of the cooker, or alternatively arranged in an induction cooker to measure the temperature of the bottom of the cooker.

[0012] The temperature sensor system disclosed in CN000109140543A is complex and expensive. Furthermore, the embodiment with the temperature sensor installed in the cooker is not suitable for use with a sensorless cooker. Summary of the Invention

[0013] The object of the present invention is therefore to provide a different method for reducing the acoustic noise generated by cookware when heated by an induction hob, which method is simpler and cheaper than the solutions disclosed above.

[0014] In accordance with this object, according to the present invention, there is provided a method for operating an induction cooktop, the induction cooktop comprising at least one induction coil for heating cookware, the method comprising the steps of: receiving a high-power user command indicating a high power level to be provided to the cookware during cooking, controlling the induction coil so as to adjust an increase in the heating power provided to the cookware from a low heating power level to the high power level, the method further comprising the steps of: receiving a silent mode command indicating a request to reduce acoustic noise generated by the cookware when heated by the induction cooktop; measuring a temperature of the induction coil; measuring a time elapsed from receipt of the high-power user command; and delaying the increase in heating power from the low heating power level to the high heating power level until a first condition or a second condition is satisfied.

[0015] Preferably, the first condition is met when the temperature of the induction coil is higher than a predetermined temperature threshold.

[0016] Preferably, the second condition is satisfied when a predetermined timeout time corresponding to a predetermined time threshold has elapsed.

[0017] Preferably, the method further comprises the steps of measuring noise / vibration of the cooker, and generating the silent mode command based on the measured noise / vibration.

[0018] Preferably, the method further comprises the step of receiving the silent mode command by the user via an interface of the induction cooktop.

[0019] The present invention further relates to an induction cooktop, comprising: at least one induction coil for heating cookware, a user interface, and an electronic control system, the electronic control system being configured to: receive, via the user interface, a high-power user command indicating a high power level to be provided to the cookware during cooking; control the induction coil so as to adjust an increase in the heating power provided to the cookware from a low heating power level to the high power level; the electronic control system being further configured to: receive a silent mode command indicating a request to reduce acoustic noise generated by the cookware when heated by the induction cooktop; measure a temperature of the induction coil; measure a time elapsed from receipt of the high-power user command; and delay the increase in heating power from the low heating power level to the high heating power level until a first condition or a second condition is satisfied.

[0020] Preferably, the electronic control system determines that the first condition is satisfied when the temperature of the induction coil is higher than a predetermined temperature threshold.

[0021] Preferably, the electronic control system determines that the second condition is met when the measured time is higher than a predetermined time threshold.

[0022] Preferably, the electronic control system is further configured to measure noise / vibration of said cooker and automatically generate said silent mode command based on said measured noise / vibration.

[0023] Preferably, the electronic control system is further configured to receive the silent mode command by the user via the user interface of the induction cooktop.

[0024] The claims describe preferred embodiments of the present invention and constitute an integral part of this description.

[0025] If not explicitly stated otherwise, embodiments of the invention can be freely combined with one another. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Various aspects of the present invention, including its specific features and advantages, will be readily understood from the following detailed description and accompanying drawings, in which:

[0027] Figure 1 The induction cooker made according to the teachings of the present invention is schematically shown.

[0028] Figure 2 is a flow chart of the operation of the induction cooktop when implementing the method provided in accordance with the present invention. DETAILED DESCRIPTION

[0029] The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments are shown. However, the present invention should not be construed as being limited to the embodiments set forth herein. Throughout the following description, similar reference numerals are used to represent similar elements, parts, objects, or features, where applicable.

[0030] refer to Figure 1 , number 1 as a whole represents the induction cooker made according to the present invention.

[0031] The induction cooktop 1 may include a cooktop plate 2 and one or more heating zones 4 (illustrated by dotted lines) arranged on the cooktop plate 2 and configured to support corresponding cookware C ( Figure 1 One of the cookers is shown schematically in ).

[0032] refer to Figure 1 In the exemplary embodiment shown, each heating zone 4 is associated with at least one induction coil 3 configured to heat the cookware C. Preferably, the induction coil 3 may be arranged below the cooktop 2 .

[0033] exist Figure 1 In the example shown, the induction cooktop 1 further comprises a user interface 5 , which is for example comprised in a control panel of the induction cooktop 1 .

[0034] The user interface 5 may be configured to allow a user to input / set commands to the induction cooktop 1 to perform cooking (cycles).

[0035] according to Figure 1 In the illustrated embodiment of the present invention, the user interface 5 may be further configured to allow the user to input / set a command to select a heating power for cooking from among a plurality of predetermined heating powers.

[0036] According to the invention, the predetermined heating power may comprise a plurality of predetermined heating powers denoted as "high heating power levels" in the following.

[0037] According to the present invention, the user interface 5 may preferably be configured to allow the user to input / set a command indicating a "boost power level" of the highest heating power level. For example, the high heating power level may have a value within the range of about 2000 W, while the boost power level may be a value of about 3000 W.

[0038] according to Figure 1 In the illustrated embodiment of the present invention, the user interface 5 may be further configured to allow the user to input / set a command for selecting a “silent mode”.

[0039] The silent mode function, when selected by a user, causes the induction cooktop 1 to operate to reduce acoustic noise generated by the cookware C during cooking.

[0040] When the user inputs / sets the silent mode function, the induction cooktop 1 works to perform the following detailed description and Figure 2 The flowchart shows the steps of the operation method.

[0041] refer to Figure 1 In the example shown, the induction cooktop 1 preferably comprises an electronic control system 6 which is configured to control the operation of the induction cooktop 1 .

[0042] Preferably, the electronic control system 6 may include an electronic control unit 7 .

[0043] Preferably, the electronic control system 6 may further include a temperature sensor 8. Figure 2 In the exemplary embodiment of FIG. 8 , the temperature sensor 8 is configured to measure the temperature Tc of the induction coil 3 .

[0044] It will be appreciated that the present invention is not limited to a temperature sensor 8 being configured to measure the temperature of the induction coil 3 , but alternatively or additionally the temperature sensor 8 may be arranged and configured to measure the temperature of the heating zone 4 .

[0045] The electronic control unit 7 may be configured to control the electric power supplied to the induction coil 3 so as to adjust the heating power provided by the induction coil 3 to the cookware C during cooking.

[0046] According to the present invention, when the user selects a high heating power level through the user interface 5, the electronic control unit 7 adjusts the electric power supplied to the induction coil 3 so that the heating power increases from a predetermined low heating power (hereinafter referred to as the initial low heating power level) to the high heating power level selected by the user.

[0047] The increase in heating power from an initial low heating power level to a high heating power level (eg, a boost level) may be implemented gradually and / or in a smoothly progressive manner.

[0048] For example, during the implementation steps, the induction cooktop 1 may maintain a predetermined initial level lower than a high heating level set by a customer for a certain period of time.

[0049] Once a coil temperature threshold or a time threshold has been reached, the transition from the predetermined initial power level to the high heating power level may be performed, for example, in one step.

[0050] According to an exemplary embodiment of the present invention, in order to implement a smooth and gradual power increase, the induction cooktop 1 starts the cooking process with an initial predetermined low heating power that is lower than the high heating power level set by the user, and then gradually increases the power according to a certain slope to reach a final power corresponding to the high heating level.

[0051] In the event that a temperature threshold has been reached, the process can be accelerated in at least one step or the final power can be obtained.

[0052] The slope of the heating power can be customized by the user and ultimately adapted to the cooker C used by the user.

[0053] During a cooking cycle, the electronic control unit 7 controls the electrical power supplied to the induction coil 3 so as to adjust the heating power provided by the induction coil to the cookware C so as to increase the heating power from a predetermined low heating power level to a high heating power level.

[0054] According to the present invention, the electronic control unit 7 is configured to receive as input a silent mode command indicating a user's request to reduce the acoustic noise generated by the cookware C when it is heated by the induction cooktop 1, and to delay the transition from the initial low heating power level to the high power level until the first condition or the second condition is met.

[0055] According to the present invention, the first condition is satisfied when the temperature of the induction coil is higher than a predetermined temperature threshold, and the second condition is satisfied when a predetermined timeout period corresponding to a time threshold has elapsed.

[0056] Applicants have discovered that acoustic noise tends to peak when the cooker C is cold and then decreases as it heats up. At the start of cooking, there's a temperature difference between the outer layer, which is immediately heated by induction, and the inner layer, which is heated by conduction. Therefore, the intensity of the noise depends on the heating power supplied to the cooker C.

[0057] The technical effect obtained by delaying the time at which the heating power is switched from the low heating power level to the high heating power level is that the acoustic noise generated by the cooker C is reduced.

[0058] refer to Figure 2 As shown in the flowchart, the method for operating the induction cooktop 1 comprises the following steps.

[0059] The method includes the step of controlling whether a silent mode command has been selected (block 100).

[0060] It will be appreciated that the silent mode function may be activated based on a user command given through the user interface 5 (block 200 ) and / or automatically activated by the sensor device 9 based on noise / vibration (block 300 ).

[0061] If silent mode is activated (output is yes, box 100), the method can check whether a command for a high power level (i.e., boost level) has been selected (box 110), and if selected (output is yes, box 110), the method measures the elapsed time te (box 120).

[0062] Furthermore, the method performs a step of measuring the temperature Tc of the induction coil 11 (block 130 ).

[0063] Next, the method controls whether the first condition or the second condition is met.

[0064] The method checks a first condition, namely whether the elapsed time te is higher than a predetermined time threshold tr (te>tr) (block 150 ).

[0065] Furthermore, the method checks a second condition, ie, whether the measured temperature Tc is higher than a temperature threshold Tr (Tc>Tr) (block 140 ).

[0066] If the measured time te is higher than the predetermined time threshold tr (output is yes, block 150), or the measured coil temperature Tc is higher than the temperature threshold Tr (output is yes, block 140), the method controls the electric power supplied to the induction coil 3 so as to increase the heating power provided to the cookware C from the initial low heating power level to a high heating power level, corresponding to a boost power level in this example.

[0067] In other words, when the first condition and the second condition are met, the heating power provided to the cooker is switched from an initial low heating power level to a high heating power level, corresponding to a boost power level in this example.

[0068] When the measured time te reaches a predetermined end time tf, the method ends.

[0069] The invention has the advantage of reducing the acoustic noise generated by a cooker by a method that is simpler and cheaper to implement than known solutions.

[0070] Clearly, changes and variations may be made to the induction cooktop and the method without departing from the scope of the present invention.

Claims

1. A method for operating an induction cooker (1), the induction cooker comprising at least one induction coil (3) for heating a cooker (C), the method comprising the following steps: receiving a high power user command indicating a high power level to be provided to said cooker (C) during cooking, controlling the induction coil (3) so as to regulate an increase in the heating power supplied to the cooker (C) from a low heating power level to the high power level, The method further comprises the following steps: receiving a silent mode command indicating a request for reducing acoustic noise generated by the cookware (C) when being heated by the induction cooktop (1), measuring the temperature of the induction coil (3), measuring the time elapsed since receipt of the high power user command, The increase of the heating power from the low heating power level to said high heating power level is delayed until a first condition or a second condition is met.

2. The method according to claim 1, wherein The first condition is met when the measured temperature of the induction coil is higher than a predetermined temperature threshold.

3. The method according to claim 1 or 2, wherein: When the measured time reaches a predetermined time threshold, the second condition is met.

4. The method according to any one of the preceding claims, comprising: - measuring the noise / vibration of said cooker (C), - generating said silent mode command based on said measured noise / vibration.

5. Method according to any of the preceding claims, comprising the step of receiving the silent mode command via a user interface (5).

6. An induction cooker (1), comprising: at least one induction coil (3) for heating the cooker (C), User interface (5) and An electronic control system (6), the electronic control system being configured to: receiving a high power user command indicating a high power level to be provided to said cooker (C) during cooking, controlling the induction coil (3) so as to regulate an increase in the heating power supplied to the cooker (C) from a low heating power level to the high power level, The electronic control system (6) is further configured to: receiving a silent mode command indicating a request for reducing acoustic noise generated by the cookware (C) during heating by the induction cooktop, Measure the temperature of the induction coil, measuring the time elapsed since receipt of the high power user command, The increase of the heating power from the low heating power level to said high heating power level is delayed until a first condition or a second condition is met.

7. The induction cooker according to claim 6, wherein: The electronic control system (6) is further configured to verify that the first condition is met when the induction coil temperature is above a predetermined temperature threshold.

8. The induction cooker according to claim 6 or 7, wherein: The electronic control system (6) is further configured to verify that the second condition is met when a predetermined timeout time corresponding to a predetermined time threshold has elapsed.

9. The induction cooktop according to any one of claims 6 to 8, wherein: The electronic control system (6) is further configured to: - measuring the noise / vibration of said cooker, - generating said silent mode command based on said measured noise / vibration.

10. The induction cooktop according to any one of claims 6 to 9, wherein: The electronic control system (6) is further configured to receive the silent mode command via the user interface.

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