An induction cooktop and a power control method for an induction cooktop

Abstract

The invention relates to an induction cooktop comprising a first cooking module (2) and at least one second cooking module (3) on a top plate (1), a first induction coil (10) and at least one second induction coil (20) within the first cooking module (2), and at least one third induction coil (30) within the second cooking module (3). The cooktop further comprises a first power control unit (50) connected to the first cooking module (2) and configured to activate the first and / or second coils (10, 20), and a controller (40) that is in signal communication with a user panel (4). In a cooking mode, the controller (40) compares the power used by the first power control unit (50) to a predefined threshold value and, based on that comparison, drives a first relay (52) that switches the first power control unit (50) at a predetermined interval.

Description

[0001] AN INDUCTION COOKTOP AND A POWER CONTROL METHOD FOR AN INDUCTION COOKTOP

[0002] TECHNICAL FIELD

[0003] The present invention relates to cooktops having multiple heating elements whose power consumption is regulated by an electronic control unit, particularly induction cooktops.

[0004] PRIOR ART

[0005] Induction cooktops are often designed to operate on two-phase or single-phase electricity. This approach allows users to select products according to their own needs and constraints. In many regions, the total electricity consumption of multiple electric appliances running at the same time must remain below limits set by standards or local authorities. For example, in countries like the United Kingdom, Israel, Italy, and others, maximum usage of 3000W or 3600W may be permitted for electric cooktops and various other electrical appliances. Consequently, products rated for 7200W in a two-phase configuration cannot be used in these countries.

[0006] On the other hand, manufacturing both single-phase and multi-phase products separately poses serious challenges in terms of time, cost, and resources. Thus, designing devices that can operate in both single-phase and multi-phase modes offers a practical, cost-effective solution. A user interface can be used to select whether the product runs on a single-phase or multi-phase supply, and the product’s maximum output power is then adapted to meet the relevant limit. However, when a product designed for multi-phase operation is run on a single-phase supply, a loss in potential performance emerges as a principal challenge.

[0007] EP4013189A1 discloses an induction cooktop with at least one cooking zone, which includes a first induction coil and a second induction coil. These two coils can heat the cookware either independently or in cooperation. The cooktop additionally features a power unit that supplies and operates the first and second induction coils, along with a control interface for receiving a demanded power setting from the user. This demanded power is the amount of power intended to be transferred to the cookware. The power unit delivers a first power to the first induction coil within a range between a first minimum and a first maximum deliverable power, and a second power to the second induction coil within a range between a second minimum and a second maximum deliverable power. The power unit selects from various powering schemes to supply the coils. Based on the demanded power and each coil’s deliverable power range (minimum and maximum values), the power unit chooses one powering scheme to supply the first and second induction coils.

[0008] BRIEF SUMMARY OF THE INVENTION

[0009] The objective of the present invention is to maintain efficient cooking operation under conditions where the total power simultaneously drawn from the mains by an induction cooktop is limited.

[0010] To achieve this objective, the invention provides an induction cooktop that includes a first cooking module and at least one second cooking module on a cooktop surface, a first induction coil and at least one second induction coil within the first cooking module, and at least one third induction coil within the second cooking module. The induction cooktop has a first power control unit linked to the first cooking module for activating the first and / or second coil, and a controller in communication with a user panel. In a cooking mode, the controller compares the power value used by the first power control unit with a predefined threshold value. Based on the comparison, it drives a first relay that switches the first power control unit over a predetermined time interval. In this way, the induction cooktop enhances energy efficiency by optimizing power control in accordance with whether the first and second cooking modules are in use. Furthermore, comparing power usage against threshold values is important for safety: once power usage exceeds a certain level, the control unit initiates a safety measure (for example, switching a relay).

[0011] In a preferred embodiment, the invention includes a second power control unit connected to the second cooking module. This unit controls the activation of the induction coils located in the second cooking module.

[0012] In another preferred embodiment, the cooktop includes a second relay, driven by the controller, that switches the second power control unit at predetermined intervals. Thus, if the mains power limit is reached, the relay can be leveraged to control the efficiency of the coils.

[0013] In yet another preferred embodiment, if the first or second induction coil in one cooking module and at least one third induction coil in the other module are all active in a cooking mode, the controller can switch both the first and second relays. This ensures that a single controller can manage the cooking operation of both the first and second cooking modules. According to a further preferred embodiment, the second cooking module may include a fourth induction coil spaced from the third induction coil, thereby providing four distinct cooking zones on the cooktop surface.

[0014] In another preferred embodiment, there is a memory unit in communication with the controller that stores threshold values and period durations. As a result, data about the control method implemented by the controller can be recorded.

[0015] In yet another preferred embodiment, the controller is configured to switch the first and / or second relay at intervals ranging from 8 to 12 seconds. Thus, the power distribution among the induction coils can be handled via a single controller.

[0016] In a further preferred embodiment, the controller switches the first and / or second relay at fixed intervals. This ensures that energy efficiency is maintained at a constant level during limited power consumption in a cooking mode.

[0017] In still another preferred embodiment, in a cooking mode, the first and second power control units each contain single-switch quasi-resonant converters (or in some configurations, halfbridge series resonant converters) that activate the respective coils.

[0018] In a preferred application, the steps include receiving a demand signal from the user panel by the controller, converting that demand signal to a required power value for the first and / or second cooking module, and switching the first and / or second power control unit at predetermined intervals based on the converted power value. In this manner, the induction coils are activated periodically to maintain cooking efficiency while staying within a limited power range.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 shows a top view of the induction cooktop configuration according to the invention.

[0021] DETAILED DESCRIPTION OF THE INVENTION

[0022] This detailed description provides illustrative examples of the invention to facilitate understanding without imposing any limitation. In Figure 1 , a top view of the induction cooktop according to the invention is presented. The induction cooktop includes a top plate (1 ), on which a first cooking module (2) is provided, and a second cooking module (3) of similar design located adjacent to the first module (2).

[0023] Within the first cooking module (2), there is a first induction coil (10). A second induction coil (20) is spaced from the first induction coil (10). A first power control unit (50) activates or deactivates both coils (10, 20). The first power control unit (50) features a Single Switch Quasi-Resonant (SSQR) converter, which minimizes switching and transition losses to enhance overall efficiency.

[0024] A controller (40) supervises the first power control unit (50). The controller (40) is in signal communication with a user panel (4) located on a circuit board (5). Implemented as a microcontroller, the controller (40) employs a first relay (52) within the first power control unit (50) to perform switching actions. The controller (40) converts the demand signal from the user panel (4) into the required power level. Based on this power level, the controller (40) decides whether the first coil (10) and second coil (20) will be activated or deactivated. If only the first coil (10) is in operation, it is activated via the first relay (52). If the first and second coils (10, 20) need to operate simultaneously, the controller (40) switches the first relay (52) at specific time intervals (e.g., every 10 seconds) according to a set algorithm.

[0025] The second cooking module (3) contains a third induction coil (30). A fourth induction coil (80) is spaced from the third induction coil (30). A second power control unit (60) activates or deactivates the third (30) and fourth (80) coils. The second power control unit (60) also includes a Single Switch Quasi-Resonant (SSQR) converter. The controller (40) employs a second relay (62) in the second power control unit (60) for switching. It converts the demand signal from the user panel (4) to a power value subject to certain limits, then determines the threshold and controls whether the third coil (30) and the fourth coil (80) should be activated or deactivated.

[0026] If only the third coil (30) is to operate, the controller (40) activates it via the second relay (62). If the third and fourth coils (30, 80) must operate simultaneously, the second relay (62) is switched at fixed intervals (e.g., every 10 seconds) according to the controller’s algorithm. When the cooking mode is deactivated, the controller (40) stores the applied switching period data in a memory unit (90). REFERENCE NUMERALS

[0027] 1 Top Plate

[0028] 2 First Cooking Module 3 Second Cooking Module

[0029] 4 User Panel

[0030] 5 Circuit Board

[0031] 10 First Induction Coil

[0032] 20 Second Induction Coil 30 Third Induction Coil

[0033] 40 Controller

[0034] 50 First Power Control Unit

[0035] 52 First Relay

[0036] 60 Second Power Control Unit 62 Second Relay

[0037] 80 Fourth Induction Coil

[0038] 90 Memory Unit

Claims

CLAIMS1. An induction cooktop comprising: a plate (1 ); a first cooking module (2) provided on the plate (1 ); at least one second cooking module (3) provided on the plate (1); a first induction coil (10) and at least one second induction coil (20) within the first cooking module (2); at least one third induction coil (30) within the second cooking module (3) characterized in that the induction cooktop further comprises: a first power control unit (50) connected to the first cooking module (and configured to activate the first and / or second coil (10, 20); a controller (40) in signal communication with a user panel (4), wherein, in a cooking mode, the controller (40) compares the power used by the first power control unit (50) to a predetermined threshold value and, based on the comparison result, drives a first relay (52) that switches the first power control unit (50) at a predetermined interval.

2. The induction cooktop according to Claim 1 , wherein a second power control unit (60) is connected to the second cooking module (3).

3. The induction cooktop according to Claim 2, wherein a second relay (62) is driven by the controller (40) to switch the second power control unit (60) at a predetermined interval.

4. The induction cooktop according to Claim 3, wherein the controller (40) is configured to switch both the first relay (52) and the second relay (62) when, in a cooking mode, at least one of the first or second induction coils (10, 20) and at least one third induction coil (30) are activated.

5. The induction cooktop according to any of the preceding claims, wherein the second cooking module (3) includes a fourth induction coil (80) spaced from the third induction coil (30).

6. The induction cooktop according to any of the preceding claims, wherein a memory unit (90) is in signal communication with the controller (40), wherein threshold values and interval durations are stored.

7. The induction cooktop according to any of the preceding claims, wherein the controller (40) is configured to switch the first relay (52) and / or the second relay (62) at intervals between 8 and 12 seconds.

8. The induction cooktop according to Claim 7, wherein the controller (40) is configured to switch the first relay (52) and / or the second relay (62) at fixed intervals.

9. The induction cooktop according to any of the preceding claims, wherein the first and second power control units (50, 60), in a cooking mode, each comprise a single-switch quasi-resonant converter that activates the coils (10, 20, 30, 40).

10. A power control method for an induction cooktop according to any of the preceding claims, comprising the steps of receiving a demand signal at the controller (40) from the user panel (4), converting the received demand signal into a power value required for the first and / or second cooking module (2, 3), and switching the first and / or second power control unit (50, 60) at predetermined intervals based on the converted power value.

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