JP7008181B2 - Load detection method in induction heating device and induction heating device - Google Patents

Description

The present disclosure relates to an induction heating device that induces and heats a load such as a metal cooking pot placed on a top plate, and in particular, a multi-coil type induction heating having a large number of heating coils provided below the top plate. Regarding the device.

In recent years, the development of multi-coil type induction heating cookers has been progressing. The multi-coil type induction heating cooker is provided with a large number of heating coils arranged in a matrix below the top plate, and is configured so that the heating region can be changed according to the situation (see Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2008-293871 International Publication No. 2014/066931

As described above, the multi-coil type heating cooker disclosed in Patent Documents 1 and 2 detects the position of the load placed on the top plate and identifies one or more heating coils to be operated. do.

This work is performed by detecting a change in an electric signal in an energization path connecting the power supply of the cooking device and each of the heating coils when a detection current, which is high-frequency power, is supplied to the heating coil. Hereinafter, this work is referred to as load detection.

How to save energy and accurately detect the load in a short time is a problem to be solved in the development of a multi-coil type induction heating device.

One aspect of the present disclosure is a top plate on which a load is placed, a plurality of heating coils provided below the top plate, and at least one drive unit configured to supply high frequency power to the plurality of heating coils. An electric signal detection unit configured to detect an electric signal related to an element included in the drive unit, and a control unit configured to input the detected electric signal to control the drive unit. It is an induction heating device equipped with.

In the induction heating device of this embodiment, the control unit controls at least one drive unit so as to repeatedly supply the detection current, which is high frequency power, to the plurality of heating coils at a predetermined detection cycle. The control unit detects the loading of the load above the plurality of heating coils based on the electric signal in response to the detection current.

When the control unit detects the loading of the load above any one of the plurality of heating coils, the control unit tentatively determines the loading status of the load. The control unit does not detect the placement of a new load above the heating coil adjacent to the heating coil related to the tentatively determined mounting condition in the detection cycle after the tentatively determined detection cycle. In that case, the tentatively determined placement status is fixed.

Another aspect of the present disclosure is a load detection method in an induction heating device. The load detection method of this embodiment is based on a step of repeatedly supplying a detection current, which is high-frequency power, to a plurality of heating coils provided below the top plate at a predetermined detection cycle, and an electric signal in response to the detection current. , Includes a step of detecting load placement above a plurality of heating coils.

Further, in the load detection method of this embodiment, when the load placement is detected above any one of the plurality of heating coils, the step of tentatively determining the load placement status and the detection that the tentative determination is performed are performed. If no load placement is detected above the heating coil adjacent to the heating coil associated with the tentatively determined placement status in at least one detection cycle following the cycle, the tentatively determined placement status is determined. Including steps.

FIG. 1 is an exploded perspective view showing an induction heating cooker according to the first embodiment. FIG. 2 is a plan view of the induction heating cooker of the first embodiment in a state where the top plate is removed. FIG. 3 is a diagram showing compartments A and B included in the left heating region Lh, the right heating region Rh, and the central heating region Ch, respectively. FIG. 4 is a functional block diagram relating to a section in which two heating coils 3 are driven by one drive unit 4. FIG. 5 is a circuit block diagram relating to a section in which two heating coils 3 are driven by one drive unit 4. FIG. 6A is a circuit block diagram which is a first modification of the circuit block diagram shown in FIG. FIG. 6B is a circuit block diagram which is a second modification of the circuit block diagram shown in FIG. FIG. 7A is a diagram schematically showing a temporal change in the peak value of the amplitude of the detection current for mounting detection. FIG. 7B is a diagram schematically showing a temporal change in the peak value of the amplitude of the detection current for mounting detection. FIG. 8A is a timing chart showing the operation of the switching elements 19a and 19b during the detection period Dp1. FIG. 8B is a timing chart showing the operation of the switching elements 19a and 19b during the detection period Dp2. FIG. 9A is a flowchart for mounting detection according to the first embodiment. FIG. 9B is a flowchart for mounting detection according to the first embodiment. FIG. 10A is a timing chart for mounting detection and position identification according to the first embodiment. FIG. 10B is a timing chart of the gate signal input to the switching elements 19a and 19b during the detection period Dp1. FIG. 10C is a timing chart of the gate signal input to the switching elements 19a and 19b during the detection period Dp2. FIG. 10D is a timing chart of the gate signal input to the switching elements 19a and 19b during the detection period Dp3. FIG. 11 is a flowchart for specifying a position according to the first embodiment. FIG. 12A is a timing chart for mounting detection and position identification according to the second embodiment. FIG. 12B is a flowchart for specifying the position according to the second embodiment. FIG. 13A is a block diagram of an induction heating cooker for explaining the concept of changing the detection cycle according to the third embodiment. FIG. 13B is a timing chart for explaining the concept of changing the detection cycle according to the third embodiment. FIG. 14A is a flowchart for changing the detection cycle according to the third embodiment. FIG. 14B is a flowchart for changing the detection cycle according to the third embodiment. FIG. 15A is a timing chart for explaining the concept of determining the placement status according to the fourth embodiment. FIG. 15B is a diagram showing a pattern of the mounting status for explaining the concept of determining the mounting status according to the fourth embodiment. FIG. 16A is a flowchart for determining the mounting state in the first detection cycle according to the fourth embodiment. FIG. 16B is a flowchart for determining the mounting state in the first detection cycle according to the fourth embodiment. FIG. 17A is a flowchart for determining the mounting state in the second and subsequent detection cycles according to the fourth embodiment. FIG. 17B is a flowchart for determining the mounting state in the second and subsequent detection cycles according to the fourth embodiment. FIG. 17C is a flowchart for determining the mounting state in the second and subsequent detection cycles according to the fourth embodiment. FIG. 18A is a flowchart for mounting detection according to the fifth embodiment. FIG. 18B is a flowchart for mounting detection according to the fifth embodiment. FIG. 19A is a flowchart for specifying a position according to the fifth embodiment. FIG. 19B is a flowchart for specifying a position according to the fifth embodiment. FIG. 20A is a flowchart for determining the mounting status according to the fifth embodiment. FIG. 20B is a flowchart for determining the mounting status according to the fifth embodiment. FIG. 21 is a flowchart for determining the mounting status according to the fifth embodiment. FIG. 22A is a flowchart for changing the detection cycle according to the fifth embodiment. FIG. 22B is a flowchart for changing the detection cycle according to the fifth embodiment.

A first aspect of the present disclosure is to supply high frequency power to a top plate on which a load is placed, a plurality of heating coils provided below the top plate, and a plurality of heating coils. At least one drive unit configured in the above, an electric signal detection unit configured to detect an electric signal related to an element included in the drive unit, and an electric signal detection unit configured to input the detected electric signal to control the drive unit. It is an induction heating device provided with a control unit configured to do so.

In the induction heating device of this embodiment, the control unit controls at least one drive unit so as to repeatedly supply the detection current, which is high frequency power, to the plurality of heating coils at a predetermined detection cycle. The control unit detects the loading of the load above the plurality of heating coils based on the electric signal in response to the detection current.

When the control unit detects the loading of the load above any one of the plurality of heating coils, the control unit tentatively determines the loading status of the load. The control unit does not detect the placement of a new load above the heating coil adjacent to the heating coil related to the tentatively determined mounting condition in the detection cycle after the tentatively determined detection cycle. In that case, the tentatively determined placement status is fixed.

According to the induction heating apparatus of the second aspect of the present disclosure, in the first aspect, the control unit is tentatively determined above the heating coil adjacent to the heating coil related to the tentatively determined mounting situation. When a new load is detected in the detection cycle after the detected cycle, it is determined that the load has moved, and the loading status in the detection cycle after the detection cycle in which the tentative decision is made is checked again. Make a tentative decision.

In the detection cycle after the detection cycle in which the tentative decision is made again, the control unit places a new load on the heating coil adjacent to the heating coil related to the tentatively determined mounting situation. If it is not detected, the tentatively determined placement status is confirmed again.

According to the induction heating apparatus of the third aspect of the present disclosure, in the first aspect, the control unit is tentatively determined above the heating coil adjacent to the heating coil related to the tentatively determined mounting situation. When a new load is detected in the detection cycle after the detected cycle, it is determined that another load has been placed, and the placement status of the other load is tentatively determined and the tentative decision is made. Determine the placement status in the detection cycle performed.

The control unit has a new load above the heating coil adjacent to the heating coil related to the mounting status of the other load in the detection cycle after the detection cycle in which the mounting status of the other load is tentatively determined. If the placement of the coil is not detected, the provisionally determined placement status is confirmed.

According to the induction heating device of the fourth aspect of the present disclosure, in the first aspect, the top plate has at least one heating region. At least one heating region has a plurality of compartments. A plurality of heating coils and at least one drive unit are provided for one of the plurality of compartments.

A fifth aspect of the present disclosure is a load detection method in an induction heating device. The load detection method of this embodiment is based on a step of repeatedly supplying a detection current, which is high-frequency power, to a plurality of heating coils provided below the top plate at a predetermined detection cycle, and an electric signal in response to the detection current. , Includes a step of detecting load placement above a plurality of heating coils.

Further, in the load detection method of this embodiment, when the load placement is detected above any one of the plurality of heating coils, the step of tentatively determining the load placement status and the detection that the tentative determination is performed are performed. If no load placement is detected above the heating coil adjacent to the heating coil associated with the tentatively determined placement status in at least one detection cycle following the cycle, the tentatively determined placement status is determined. Including steps.

According to the load detection method of the induction heating device of the sixth aspect of the present disclosure, in the fifth aspect, the tentative determination is made above the heating coil adjacent to the heating coil related to the tentatively determined mounting condition. When a new load is detected in the detection cycle after the detected cycle, it is determined that the load has moved, and the loading status in the detection cycle after the detection cycle in which the tentative decision is made is checked again. In the step of tentative determination and the detection cycle after the detection cycle in which the tentative determination is made again, a new load is placed above the heating coil adjacent to the heating coil related to the mounting condition that has been tentatively determined again. If the placement is not detected, it further includes a step of determining the placement status that has been tentatively determined again.

According to the load detection method of the induction heating device according to the seventh aspect of the present disclosure, in the fifth aspect, the tentative determination is made above the heating coil adjacent to the heating coil related to the tentatively determined mounting condition. When a new load is detected in the detection cycle after the detected cycle, it is determined that another load has been placed, and the placement status of the other load is tentatively determined and the tentative decision is made. In the heating coil related to the mounting status of other loads in the step of determining the mounting status in the performed detection cycle and the detection cycle after the detection cycle in which the mounting status of other loads is tentatively determined. If no new load placement is detected above the adjacent heating coil, it further includes a step of determining the tentatively determined placement status.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In all the figures below, the same or equivalent parts are designated by the same reference numerals, and duplicate description is omitted.

Each embodiment is a specific example of the present disclosure. The numerical values, shapes, configurations, steps, steps, and the like shown in the embodiments are examples, and do not limit the present disclosure.

The present disclosure also includes configurations in which the configurations according to some embodiments are appropriately combined. As such, the combined configuration has all the effects of the relevant embodiments.

Here, an induction heating cooker as an example of the induction heating device of the present disclosure will be described. However, the present disclosure is not limited to the induction heating cooker.

In embodiments, left and right mean left and right when the induction cooker is viewed by a user operating the induction cooker, respectively. The user side of the induction heating cooker is defined as the front side of the induction heating cooker, and the side opposite to the user side of the induction heating cooker is defined as the rear side of the induction heating cooker.

(Embodiment 1)
FIG. 1 is an exploded perspective view showing an induction heating cooker which is an induction heating device according to the first embodiment of the present disclosure. FIG. 2 is a plan view of the induction heating cooker of the present embodiment in a state where the top plate is removed.

As shown in FIGS. 1 and 2, the induction heating cooker of the present embodiment includes a housing 1, a top plate 2 that covers the upper portion of the housing 1, and a plurality of heatings provided inside the housing 1. It has a coil 3 and an operation display unit 5.

The plurality of heating coils 3 are arranged in vertical and horizontal rows. The heating coil 3 has an elliptical shape in a plan view.

Due to the arrangement of the heating coil 3 shown in FIG. 2, the top plate 2 has a left heating region Lh on the left side thereof, a right heating region Rh on the right side thereof, and a central heating region Ch between the left heating region Lh and the right heating region Rh. Have. An operation display region P is provided between the left heating region Lh and the right heating region Rh and in front of the central heating region Ch.

Four heating coils 3 are arranged below the left heating region Lh and the right heating region Rh, respectively. These heating coils are arranged in a row in the front-rear direction with the elliptical long axis oriented in the left-right direction.

Below the central heating region Ch, three heating coils 3 are arranged. These heating coils are arranged in a row in the left-right direction with the long axis of the ellipse facing the front-back direction. The heating region H is composed of the left heating region Lh, the right heating region Rh, and the central heating region Ch.

In the present embodiment, the number of heating coils 3 provided in the left heating region Lh, the right heating region Rh, and the central heating region Ch is an example, and the number is not limited thereto. Although a plurality of elliptical heating coils 3 are used in a plan view, a circular heating coil 3 may be used in a plan view. The elliptical shape includes not only an elliptical shape in a strict sense but also a shape having a curved corner portion such as an oval shape or a shape like an athletics track.

The operation display unit 5 is a touch panel device having a liquid crystal display unit provided below the operation display area P. When the induction heating cooker is activated, the operation display unit 5 displays an operation button, an operation menu, an operation content, an operation state, and the like.

As shown in FIG. 2, a plurality of temperature sensors are provided in order to detect the temperature of the load placed on the heating region H. Specifically, in the left heating region Lh and the right heating region Rh, an infrared sensor 6 is provided between two adjacent heating coils 3, and a thermistor 7 is provided at the center of each of the heating coils 3.

In the central heating region Ch, the thermistor 7 is provided at the center of the heating coils 3 located in the center of the three heating coils 3. Thermistors 7 are provided on the outer periphery of the two heating coils 3 located at both ends of the three heating coils 3 facing the left heating region Lh and the right heating region Rh, respectively. An infrared sensor 6 is provided between two adjacent heating coils 3.

According to this configuration, the temperature of the load can be detected with high accuracy no matter where the load is placed on the heating region H.

Inside the housing 1, a drive unit 4 (not shown in FIG. 2) for driving the heating coil 3 and a drive control unit 11 (not shown in FIG. 2) for controlling the operation display unit 5 and the drive unit 4 and the like. ) And are provided. The drive unit 4 and the drive control unit 11 will be described later.

FIG. 3 shows two compartments (compartments A and B) contained in the left heating region Lh, the right heating region Rh, and the central heating region Ch, respectively.

As shown in FIG. 3, in the left heating region Lh and the right heating region Rh, the compartment A has two heating coils 3, that is, a heating coil A1 and a heating coil A2 arranged behind the heating coil A1. The compartment B has two heating coils 3, that is, a heating coil B1 and a heating coil B2 arranged behind the heating coil B1.

In the central heating region Ch, the compartment A has the heating coil 3 at the right end of the three heating coils 3, that is, the heating coil A2. The compartment B has the remaining two heating coils 3, that is, the heating coil B1 and the heating coil B2 arranged on the left side thereof.

One drive unit 4 is provided in each section. That is, the induction heating cooker of the present embodiment has a total of six drive units 4. In the section A of the central heating region Ch, one drive unit 4 drives one heating coil 3. In the other compartments, one drive unit 4 drives two heating coils 3 via the switching unit 8.

4 and 5 are functional block diagrams and circuit block diagrams relating to a compartment in which two heating coils 3 are driven by one driving unit 4 (for example, compartment A of the left heating region Lh), respectively.

As shown in FIGS. 4 and 5, two heating coils 3 (heating coils A1 and A2) are connected in parallel. The switching unit 8 is controlled by the drive control unit 11 and includes relays 8a and 8b that connect or disconnect each of the heating coils A1 and A2 and the drive unit 4, respectively. The relays 8a and 8b are composed of a mechanical relay or a semiconductor type relay.

The drive unit 4 converts the power of the commercial power supply 12 into high frequency power. The drive unit 4 supplies high-frequency power to the heating coils A1 and A2 via the relays 8a and 8b, respectively.

The load detection unit 10 determines whether or not a load is placed above the heating coil A1 and the heating coil A2 based on the detected input current and output current. The drive control unit 11 controls the drive unit 4 according to the determination. In the present embodiment, the load detection unit 10 and the drive control unit 11 constitute the control unit 50.

The drive unit 4 includes a diode bridge 15, a filter circuit 18, an inverter 9, a snubber capacitor 20, resonance capacitors 21a and 21b, an input current detector 13, and an output current detector 14.

The diode bridge 15 rectifies the AC power of the commercial power supply 12 and outputs DC power. The filter circuit 18 has a choke coil 16 and a capacitor 17, and filters the rectified DC power.

The inverter 9 is configured by connecting a switching element 19a arranged on the high voltage side and a switching element 19b arranged on the low voltage side in series. For the switching elements 19a and 19b, for example, an IGBT is used. A reverse conduction diode is connected in parallel to the switching elements 19a and 19b, respectively. The inverter 9 is connected to both ends of the capacitor 17. The drive control unit 11 controls the switching elements 19a and 19b.

The resonance capacitor 21a is connected in series with the heating coil A1 and constitutes a resonance circuit together with the heating coil A1. The resonance capacitor 21b is connected in series with the heating coil A2 and constitutes a resonance circuit together with the heating coil A2.

The snubber capacitor 20 reduces the switching loss that occurs when the switching elements 19a and 19b are turned off. The snubber capacitor 20 is connected in parallel to the switching element 19b.

The input current detector 13 is an electric signal detection unit on the input side of the drive unit 4 that detects the current supplied to the diode bridge 15. The output current detector 14 is an electric signal detection unit on the output side of the drive unit 4 that detects the current flowing through the inverter 9. These electric signal detectors detect a voltage value, a current value, and a power value obtained by calculation.

FIG. 6A is a circuit block diagram which is a first modification of the circuit block diagram shown in FIG. As shown in FIG. 6A, in this modification, the drive unit 4 includes the resonance capacitor 21c instead of the resonance capacitors 21a and 21b. The drive unit 4 includes an input voltage detector 22 and an output current detector 23 instead of the input current detector 13 and the output current detector 14.

Further, the drive unit 4 is connected in series with the inverter 9 and includes a clamp capacitor 24 for suppressing the voltage generated in the resonance capacitor 21c.

The input voltage detector 22 is an electric signal detection unit on the input side of the drive unit 4. The output current detector 23 is an electric signal detection unit on the output side of the drive unit 4.

The resonance capacitor 21c is connected in parallel with any of the heating coils A1 and A2 connected in parallel. The resonance capacitor 21c constitutes one resonance circuit together with the heating coil A1 and another resonance circuit together with the heating coil A2.

The input voltage detector 22 is an electric signal detection unit on the input side of the drive unit 4 that detects the output voltage of the filter circuit 18. The output current detector 23 is an electric signal detection unit on the output side of the drive unit 4 that detects the current flowing through the inverter 9. The load detection unit 10 determines whether or not a load is placed on the top plate 2 based on the detection values of the input voltage detector 22 and the output current detector 23.

FIG. 6B is a circuit block diagram which is a second modification of the circuit block diagram shown in FIG. As shown in FIG. 6B, in this modification, in addition to the configuration of the first modification shown in FIG. 6A, the drive unit 4 is a series of the resonance capacitor 21d and the relay 25 connected in parallel to the resonance capacitor 21c. Has.

In this modification, when both the relay 8a and the relay 8b are turned on, the drive control unit 11 turns on the relay 25. By connecting the resonance capacitor 21d in parallel with the resonance capacitor 21c, the combined capacitance of the resonance capacitors 21c and 21d changes to a value suitable for that case.

[Load detection]
The induction heating cooker of the present embodiment has a wide heating region H formed by arranging a plurality of heating coils 3 below the top plate 2. Therefore, it is necessary to quickly and accurately detect the position of the load placed on the heating region H and specify the heating coil to be operated.

Therefore, the induction heating cooker of the present embodiment periodically executes load detection after starting. Load detection includes placement detection and position identification. Placement detection means determining whether or not a load is placed somewhere in the heating region H, and position specification specifies the heating coil 3 on which the load is placed above. Means that.

Hereinafter, the treatment in the compartment A and the compartment B of the left heating region Lh will be described. The same treatment is performed in parallel in the right heating region Rh and the central heating region Ch.

[Placement detection]
For mounting detection, two types of detection currents (detection current Ds1 and second detection current Ds2) for load detection are supplied to the heating coils 3 arranged in the compartments A and B. The current value of the detected current Ds2 is larger than the current value of the detected current Ds1. The current value of these detected currents is smaller than the current value of high frequency power for inducing and heating the load during cooking. The detection current Ds1 and the detection current Ds2 correspond to the first detection current and the second detection current, respectively.

7A and 7B schematically show the temporal change of the peak value of the amplitude of the detection current supplied to the heating coils 3 arranged in the compartments A and B for the placement detection.

As shown in FIG. 7A, the detection current Ds1 is supplied to the heating coils 3 arranged in the compartments A and B during the detection period Dp1. This makes it possible to detect a relatively large load, for example, a pot having a diameter of about 150 mm or more.

When the load is not detected by the detection current Ds1, the detection current Ds2 is supplied to the heating coils 3 arranged in the compartments A and B during the detection period Dp2 following the detection period Dp1 as shown in FIG. 7B. The detection period Dp1 and the detection period Dp2 correspond to the first detection period and the second detection period, respectively.

FIG. 8A is a timing chart showing the operation of the switching element 19a and the switching element 19b during the detection period Dp1. FIG. 8B is a timing chart showing the operation of the switching elements 19a and 19b during the detection period Dp2.

As shown in FIG. 8A, when the switching element 19b is turned on at the on-time Ton1 during the detection period Dp1, the detection current Ds1 flows through the heating coil 3.

As shown in FIG. 8B, when the switching element 19b is turned on at the on-time Ton2 during the detection period Dp2, the detection current Ds2 flows through the heating coil 3.

The on-time Ton2 is longer than the on-time Ton1. The detection periods Dp1 and Dp2 are both 10 to 20 ms. The switching period of the switching elements 19a and 19b is 50 μsec. The cycle for executing load detection (hereinafter referred to as a detection cycle) is, for example, any time between 1.2 and 2.0 seconds. In the present embodiment, the predetermined detection cycle (detection cycle T0) is set to 1.7 seconds.

9A and 9B are flowcharts for mounting detection according to the present embodiment. The mounting detection must be performed before the user instructs the operation display unit 5 to start heating. In the present embodiment, when the induction heating cooker is activated, the placement detection starts. The induction heating cooker may have a proximity sensor so that when it detects that a person has approached the vicinity of the induction heating cooker, the placement detection starts.

As shown in FIG. 9A, in step S9-1, the drive control unit 11 turns on the off relay (if any) among the relays 8a and 8b of the compartment A, and the heating coil A1 of the compartment A is turned on. And A2 are connected to the inverter 9. In step S9-2, the drive control unit 11 turns on the off relay (if any) of the relays 8a and 8b of the compartment B, and connects the heating coils B1 and B2 of the compartment B to the inverter 9. do.

Before the mounting detection is performed, all the relays in the left heating region Lh are turned on, and all the heating coils 3 are connected to the inverter 9.

In step S9-3, the detection current Ds1 is supplied to the heating coils A1 and A2 during the detection period Dp1 (10 to 20 ms) during the on-time Ton1 which is the first predetermined time.

In step S9-4, the load detection unit 10 makes a predetermined determination with respect to the detection values of the input current detector 13 and the output current detector 14 in the section A.

If the result in step S9-4 is Yes, in step S9-7, the load detection unit 10 determines that the load is placed on the section A.

If the result in step S9-4 is No, in step S9-5, the detection current Ds2 is applied to the heating coils A1 and A2 during the on-time Ton2, which is the second predetermined time during the detection period Dp2 (10 to 20 ms). Will be supplied.

In step S9-6, the load detection unit 10 makes the same determination as in step S9-4 with respect to the detection values of the input current detector 13 and the output current detector 14.

If the result in step S9-6 is Yes, in step S9-7, the load detection unit 10 determines that the load is placed on the section A. If the result in step S9-6 is No, in step S9-8, the load detection unit 10 determines that the load is not placed on the section A.

The determination for mounting detection in steps S9-4 and S9-6 is made based on the detection values of the input current detector 13 and the output current detector 14.

Specifically, the load detector 10 has a first threshold value for the input current detector 13 and a second threshold value for the output current detector 14. The load detection unit 10 detects that the detection value of the input current detector 13 is equal to or higher than the first threshold value and that the detection value of the output current detector 14 is equal to or higher than the second threshold value.

When either of the detection values becomes equal to or higher than the threshold value, the load detection unit 10 has an area in which the mounted load is at least a predetermined ratio (for example, 40%) of the heating region H facing the heating coils A1 and A2. Is determined to occupy.

The determination for mounting detection is based on the detection value itself as described above, or instead, two consecutive detection values in each of the input current detector 13 and the output current detector 14. It may be done based on the change of.

The threshold used in step S9-4 may be the same as or different from the threshold used in step S9-6.

Similarly, in the modification shown in FIGS. 6A and 6B, the determination for mounting detection is the detection value of the input voltage detector 22 and the output current detector 23, and / or the input voltage detector 22 and the output current. It is performed based on the change of two consecutive detection values in each of the detectors 23.

As described above, the current value of the detection current Ds1 is smaller than the current value of the detection current Ds2. Therefore, the load detected during the detection period Dp2 is smaller than the load detected during the detection period Dp1. A small pot with a minimum diameter of 110 mm corresponds to the load detected during the detection period Dp2, but metal substances smaller than 100 mm × 20 mm × 1.0 mm (eg, knife, fork) are detected during the detection period Dp2. Not applicable to load.

Next, the load detection unit 10 determines whether or not a load is placed in the compartment B. The placement detection for the compartment B is substantially the same as the placement detection for the compartment A.

In step S9-9, the detection current Ds1 is supplied to the heating coils B1 and B2 connected in parallel to the on-time Ton1 which is the first predetermined time during the detection period Dp1 (10 to 20 ms). The process proceeds to FIG. 9B.

In step S9-10, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14.

If the result in step S9-10 is Yes, in step S9-13, the load detection unit 10 determines that the load is placed on the compartment B.

If the result in step S9-10 is No, in step S9-11, the on-time Ton2, which is the second predetermined time during the detection period Dp2 (10 to 20 ms), is connected to the heating coils B1 and B2 connected in parallel. The detection current Ds2 is supplied to.

In step S9-12, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14.

If the result in step S9-12 is Yes, in step S9-13, the load detection unit 10 determines that the load is placed on the compartment B. If the result in step S9-12 is No, in step S9-14, the load detection unit 10 determines that the load is not placed on the section B.

The determination in steps S9-10 and S9-12 is performed in the same manner as the determination in steps S9-4 and S9-6, respectively.

Since the mounting detection is executed periodically, if a large high-frequency current is used for the mounting detection, a large leakage magnetic field may be generated from the heating coil 3 on which the load is not mounted. In the heating coil 3 on which the load is placed, the load may be unnecessarily heated.

According to this embodiment, the detection current Ds1 is supplied to the heating coil 3 for a short time (on time Ton1). As a result, if the load is large to some extent, the load can be detected accurately in a short time with energy saving. When the load is not detected by the detection current Ds1, the load can be detected to a certain extent by performing the mounting detection again using the detection current Ds2.

In addition to the circuit configurations shown in FIGS. 5, 6A and 6B, the induction heating device of the present embodiment may have a configuration in which one driving unit 4 drives one heating coil. The induction heating device of the present embodiment may have a configuration in which one driving unit 4 drives three or more heating coils 3 via a switching unit 8.

[Positioning]
FIG. 10A is a timing chart for mounting detection and position identification in the compartments A and B of the left heating region Lh. As shown in FIG. 10A, in the present embodiment, mounting detection and position identification are repeatedly performed in a predetermined detection cycle T0. In the detection cycle T0, first, the above-mentioned placement detection is sequentially and individually performed for the compartments A and B.

After that, the position is specified in the order of the heating coil A1 in the section A, the heating coil A2 in the section A, the heating coil A1 in the section B, and the heating coil A2 in the section B. The switching unit 8 of the compartments A and B switches the connection so as to turn on the relay corresponding to the heating coil 3 to which the detection current Ds3 should be supplied during the detection period Dp3. The detection current Ds3 corresponds to the third detection current.

After the detection current Ds3 is supplied to the heating coil A2, the relay 8b in the compartment A is kept on. After the detection current Ds3 is supplied to the heating coil B2, the relay 8b in the compartment B is kept on.

In this embodiment, the detection period Dp3 is 200 ms. The switching period of the switching elements 19a and 19b is 50 μsec. The detection cycle T0 is any time between 1.2 and 2.0 seconds. The detection cycle T0 is set to 1.7 seconds. The detection period Dp3 corresponds to the third detection period.

The signal shown in FIG. 10B is the same as the signal shown in FIG. 8A, and is a gate signal input to the switching elements 19a and 19b during the detection period Dp1 (see FIG. 10A) for performing the placement detection. In FIG. 10B, the on-time Ton1 is 5 μsec, and the switching period of the switching elements 19a and 19b is 50 μsec.

The signal shown in FIG. 10C is the same as the signal shown in FIG. 8B, and is a gate signal input to the switching elements 19a and 19b during the detection period Dp2 (see FIG. 10A) for performing the placement detection. In FIG. 10C, the on-time Ton2 is 9 μsec, and the switching period of the switching elements 19a and 19b is 50 μsec.

The signal shown in FIG. 10D is a gate signal input to the switching elements 19a and 19b during the detection period Dp3 (see FIG. 10A) for specifying the position.

In FIG. 10D, the on-time Ton3 of the switching element 19b gradually increases to a predetermined maximum value. The maximum value of the on-time Ton3 is longer than the on-time Ton2. When the region identification is completed before the on-time Ton3 reaches the maximum value, the increase in the on-time Ton3 ends.

In the present embodiment, one cycle of the switching operation in the switching elements 19a and 19b is 50 μsec. The on-time Ton3 corresponds to the third predetermined time. The detection current Ds3 also increases as the on-time Ton3 increases.

FIG. 11 is a flowchart for specifying a position according to the present embodiment. As a result of the placement detection, when it is determined that the load is placed in any of the sections A and B, the position identification is started.

As shown in FIG. 11, in step S11-1, if the result of the placement detection shown in FIG. 9A is “a load is placed on the section A”, the process proceeds to step S11-2. If not, the process proceeds to step S11-3.

In step S11-2, the detection currents Ds3 are sequentially and individually supplied to the heating coils A1 and A2. The load detection unit 10 identifies the position in the section A by determining whether or not a load is placed above each of the heating coils A1 and A2.

The determination for position identification in step S11-2 is the detection value of the input current detector 13 and the output current detector 14 and / or the input current detector 13 and the output current detection, as in the case of the mounting detection described above. It is performed based on the change of two consecutive detection values in each of the vessels 14.

After the position is specified for the section A, the position for the section B is specified in steps S11-3 and S11-4 in the same manner as in steps S11-1 and S11-2.

The operation display unit 5 emits light at the location of the operation display area P corresponding to the loading status of the load in the heating region H. This is the state in which load detection is completed for all of the heating coils 3 before the start of induction heating. Hereinafter, the loading status of the load may be simply referred to as the loading status.

In this state, the drive control unit 11 turns on the relays 8a and 8b of all the switching units 8. As a result, the load detection can be performed at the location of the heating region H where the load is not placed, and the load detection is continuously performed at the location of the heating region H where the load is placed.

As a result, when the mounting condition changes in the heating region H where the load is placed, the change can be detected. A change in placement status means that a load has been moved, removed or added.

In a situation where both the heating coils A1 and A2 are connected to the inverter 9, for example, when a load is placed above the heating coil A1 and no load is placed above the heating coil A2, the relay 8b is placed. It is turned off and the heating coil A2 is disconnected from the inverter 9.

This operation is performed when the same detection result is continuously obtained a predetermined number of times after the determination of the above situation. This is because if this operation is performed immediately after the above situation is detected, for example, the heating coil A2 is disconnected from the inverter 9 only by the user lifting the load and immediately repositioning the load.

For example, in the section A, when the switching unit 8 disconnects the heating coil A1 from the inverter 9 and connects the heating coil A2 to the inverter 9, the detection value of the electric signal detection unit changes by a predetermined amount or more. At that time, load detection is sequentially performed for the heating coils A1 and A2 individually.

If the result is the same as before detecting the change in the detected value, the load detecting unit 10 determines that there is no change in the mounting condition, and the switching unit 8 determines that there is no change in the detected value. The same state, that is, the state where the heating coil A1 is separated from the inverter 9 and the heating coil A2 is connected to the inverter 9 is returned. This is because it is highly possible that the change in the detected value is due to a slight movement of the load, which does not require the heating coil 3 to be operated to be changed.

If the result is different from that before detecting the change in the detected value, both the heating coils A1 and A2 are connected to the inverter 9 and the load detection is executed.

According to this embodiment, the operation of the relays 8a and 8b can be reduced as much as possible. When the relays 8a and 8b are mechanical relays, the generation of switching sound can be suppressed.

When the load detection for all the heating coils 3 is completed, the drive control unit 11 turns on the relays 8a and 8b of all the switching units 8 so as to connect all the heating coils 3 to the inverter 9.

As described above, according to the induction heating device of the present embodiment, the control unit 50 controls the drive unit 4 so as to supply the detection current Ds1 which is high frequency power to the heating coils A1 and A2. The control unit 50 determines whether or not a load is placed above the heating coils A1 and A2 based on the change in the electric signal.

When the control unit 50 determines that the load is not placed above the heating coils A1 and A2, the control unit 50 supplies the heating coils A1 and A2 with the detection current Ds2, which is high frequency power and has a current value larger than the detection current Ds1. The drive unit 4 is controlled so as to do so.

The control unit 50 determines whether or not a load is placed above the heating coils A1 and A2 based on the change in the electric signal.

When the detection current Ds1 or Ds2 is supplied, the control unit 50 controls the switching unit 8 so that all of the heating coils A1 and A2 are connected to the drive unit 4. The control unit 50 determines whether or not a load is placed above the heating coils A1 and A2 based on the change in the electric signal.

When the control unit 50 determines that the load is placed above the heating coils A1 and A2, the control unit 50 sequentially and individually supplies the detection current Ds3, which is high frequency power, to each of the heating coils A1 and A2. It controls the drive unit 4 and the switching unit 8. The control unit 50 determines whether or not a load is placed above each of the heating coils A1 and A2.

Further, according to the induction heating device of the present embodiment, the top plate 2 has a left heating region Lh, a central heating region Ch, and a right heating region Rh, and these heating regions have compartments A and B for heating. The coils A1 and A2 and the drive unit 4 are provided for the compartment A of the compartments A and B.

Thereby, the position of the load placed on the heating region H can be detected quickly and accurately, and the heating coil to be operated can be specified.

Further, according to the induction heating device of the present embodiment, the control unit 50 controls the drive unit 4 and the switching unit 8 so as to supply the detection currents Ds1 and Ds2 to the heating coils A1 and A2, and the control unit 50. Determines whether or not a load is placed above the heating coils A1 and A2 based on the change in the electric signal.

When the control unit 50 determines that the load is placed above the heating coils A1 and A2, the control unit 50 switches the drive unit 4 and the switching unit so as to sequentially and individually supply the detection current Ds3 to each of the heating coils A1 and A2. The unit 8 is controlled to determine whether or not a load is placed above each of the heating coils A1 and A2.

The control unit 50 controls the switching unit 8 so as to connect the heating coils A1 and A2 to the drive unit after determining each of the heating coils A1 and A2.

In the present embodiment, the microcomputer constitutes the load detection unit 10 and the drive control unit 11. The present disclosure is not limited to this, but if a programmable microcomputer is used, the processing content can be easily changed and the degree of freedom in design can be increased.

In order to improve the processing speed, it is also possible to configure the load detection unit 10 and the drive control unit 11 with a logic circuit. The load detection unit 10 and the drive control unit 11 may be physically composed of one or a plurality of elements. When the load detection unit 10 and the drive control unit 11 are each composed of a plurality of elements, each item may be associated with one element. In this case, it can be considered that these a plurality of elements correspond to the load detection unit 10 and the drive control unit 11, respectively.

(Embodiment 2)
Hereinafter, the position specification in the induction heating cooker according to the second embodiment of the present disclosure will be described.

The induction heating cooker of the present embodiment has the same configuration as that of the first embodiment, and performs the same mounting detection as that of the first embodiment. The present embodiment is different from the first embodiment in that the position identification shown in FIGS. 12A and 12B is performed instead of the position identification shown in FIGS. 10A and 11. The position specification according to the present embodiment is a modification of the position specification according to the first embodiment.

In the present embodiment, the treatment in the left heating region Lh in the compartment A and the compartment B will be described as in the case of the first embodiment. The same treatment is performed in parallel in the right heating region Rh and the central heating region Ch.

[Position-specific transformation example]
FIG. 12A is a timing chart for mounting detection and position identification in the compartments A and B of the left heating region Lh. FIG. 12A differs from FIG. 10A only in the order of positioning.

That is, in FIG. 10A, the positions of the heating coil A1, the heating coil A2, the heating coil B1, and the heating coil B2 are specified in this order. However, in the present embodiment, as shown in FIG. 12A, the positions of the heating coil A1, the heating coil B2, the heating coil A2, and the heating coil B1 are specified in this order. The switching unit 8 of the compartments A and B switches the connection so as to turn on the relay corresponding to the heating coil 3 to which the detection current Ds3 should be supplied during the detection period Dp3.

After the detection current Ds3 is supplied to the heating coil A2, the relay 8b in the compartment A is kept on. After the detection current Ds3 is supplied to the heating coil B1, the relay 8a in the compartment B is kept on.

The gate signals input to the switching elements 19a and 19b in the detection periods Dp1, Dp2, and Dp3 are the same as those shown in FIGS. 10B, 10C, and 10D, respectively.

FIG. 12B is a flowchart for specifying a position according to the present embodiment. As shown in FIG. 12B, in step S12-1, if the result of the placement detection shown in FIG. 9A is “a load is placed on the section A”, the process proceeds to step S12-2. If not, the process proceeds to step S12-3.

In step S12-2, the detection current Ds3 is supplied to the heating coil A1. The load detection unit 10 determines whether or not a load is placed above the heating coil A1.

In step S12-3, if the result of the placement detection shown in FIG. 9A is "a load is placed on the section B", the process proceeds to step S12-4. If not, the process proceeds to step S12-5.

In step S12-4, the detection current Ds3 is supplied to the heating coil B2. The load detection unit 10 determines whether or not a load is placed above the heating coil B1.

In step S12-5, if the result of the placement detection shown in FIG. 9A is "a load is placed on the section A", the process proceeds to step S12-6. If not, the process proceeds to step S12-7.

In step S12-6, the detection current Ds3 is supplied to the heating coil A2. The load detection unit 10 determines whether or not a load is placed above the heating coil A2.

In step S12-7, if the result of the placement detection shown in FIG. 9A is "a load is placed on the section B", the process proceeds to step S12-8. If not, the position identification process ends.

In step S12-8, the detection current Ds3 is supplied to the heating coil B1. The load detection unit 10 determines whether or not a load is placed above the heating coil B2. This completes the position identification process.

The determination for position identification in steps S12-2, S12-4, S12-6, and S12-8 is the same as in the first embodiment, the detection values of the input current detector 13 and the output current detector 14, and / Alternatively, it is performed based on the change of two consecutive detection values in each of the input current detector 13 and the output current detector 14.

Based on these determinations, the positions in the compartments A and B are specified.

According to the present embodiment, the detection current is supplied to the compartment A and the compartment B from the corresponding drive unit 4. Therefore, for example, the detection period Dp3 for the heating coil B1 in the compartment B can be overlapped with the detection period Dp3 for the heating coil A1 in the compartment A. As a result, the detection cycle can be shortened.

As described above, after the detection current Ds3 is supplied to the heating coil A2, the relay 8b in the compartment A is kept on. After the detection current Ds3 is supplied to the heating coil B1, the relay 8a in the compartment B is kept on. Therefore, for example, when a load is placed across the heating coils A2 and B1, the heating coils A2 and B1 can be operated immediately without switching the connection of the switching unit 8 after the position has been specified.

(Embodiment 3)
Hereinafter, the change of the detection cycle in the induction heating cooker according to the third embodiment of the present disclosure will be described. According to the present embodiment, in the same configuration as that of the first embodiment shown in FIGS. 1 to 5, in addition to the load detection shown in FIGS. 7A to 11, the detection cycle is changed.

[Change detection cycle]
FIG. 13A is a block diagram of an induction heating cooker for explaining the concept of changing the detection cycle according to the present embodiment. As shown in FIG. 13A, the induction heating cooker for conceptual explanation includes four heating coils (heating coils 31 to 34) arranged in a row below the top plate 2, and four heating coils for driving each heating coil. It has a multi-coil type including a drive unit 4.

FIG. 13B is a timing chart for explaining the concept of changing the detection cycle in the induction heating cooker shown in FIG. 13A.

The upper half of FIG. 13B shows the detection periods Dpa1 to Dpk1, Dpa2 to Dpk2, Dpa3 to Dpk3, in which the mounting detection is performed on the heating coils 31 to 34 in the detection cycles T (a) to T (k), respectively. The periods Dpa4 to Dpk4 are shown. The length of each of the detection cycles T (a) to T (k) is equal to the above-mentioned detection cycle T0.

In these detection periods, the load detection unit 10 detects whether or not a load is mounted above the heating coils 31 to 34, similarly to the mounting detection performed in the detection period Dp1 shown in FIG. 12A. ..

The lower half of FIG. 13B shows whether or not the load is placed above the heating coils 31-34. Specifically, the lower half of FIG. 13B shows that the load placed above the heating coils 31 and 32 has moved above the heating coils 32 and 33.

Therefore, as shown in the upper half of FIG. 13B, it is detected that the load is placed above the heating coils 31 and 32 in the detection cycles T (a) and T (b). In response to this result, the heating coils 31 and 32 are not provided with a detection period in the detection cycles T (c) and T (d), but are provided with a detection period in the detection cycle T (e).

That is, when the load placement is detected twice in succession, the detection cycle increases. In FIG. 13B, the detection cycle is extended to a detection cycle T1 that is three times the detection cycle T0.

Next, the change of the detection cycle when the load moves will be described.

As shown in the lower half of FIG. 13B, when the load placed above the heating coils 31 and 32 moves above the heating coils 32 and 33 in the detection cycle T (f), the detection to the heating coils 33 is detected. During the period Dpf3 (see the upper half of FIG. 13B), the load detection unit 10 detects that the load is placed above the heating coil 33.

In response to this result, in the detection cycle T (g), a detection period is provided for the heating coils 31 to 34, and the mounting detection is performed. That is, for the heating coils 31 and 32, the detection cycle that was the detection cycle T1 is shortened to the detection cycle T2. As a result, the load detection unit 10 detects that the load placed above the heating coils 31 and 32 has moved above the heating coils 32 and 33.

In the detection cycles T (g) and T (h), a detection period is provided for the heating coils 31 to 34, and the mounting detection is performed. When the load placement is detected twice in succession, the detection period is not provided in the detection cycles T (i) and T (j) for the heating coils 32 and 33, and the detection cycle T (k) is used. A detection period is provided. That is, for the heating coils 32 and 33, the detection cycle is extended to the detection cycle T1 which is three times the detection cycle T0.

According to the concept of changing the detection cycle, in the multi-coil type induction heating cooker, the mounting detection is performed every detection cycle T1 for the heating coil in which the loading of the load is detected above the heating coil. For the heating coil in which no load is detected above it, load detection is performed in the detection cycle T0.

When it is detected that a load is placed above the heating coil on which the load has not been placed, a detection period is provided for all the heating coils in the subsequent detection cycle. That is, the detection cycle is shortened. In the heating coil in which the loading of the load is newly detected, if there is no change in the mounting condition thereafter, the detection cycle is extended again.

According to the concept of changing the detection cycle, the frequency of placement detection is reduced for a load that has already been recognized. As a result, it is possible to suppress heat generation of the load due to the detection current. When a plurality of heating coils are driven by one drive unit via the switching unit, the switching operation of the switching unit can be reduced.

Hereinafter, the change of the detection cycle when the above concept is applied to the induction heating cooker having the circuit configuration shown in FIG. 5 will be described.

In the present embodiment, the treatment in the left heating region Lh in the compartment A and the compartment B will be described as in the case of the first and second embodiments. The same treatment is performed in parallel in the right heating region Rh and the central heating region Ch.

14A and 14B are flowcharts for changing the detection cycle according to the present embodiment. The change of the detection cycle shown in FIGS. 14A and 14B is executed after the load detection including the above-mentioned placement detection and, if necessary, the above-mentioned position identification is executed.

As shown in FIGS. 14A and 14B, in step S14-1, the drive control unit 11 determines whether or not the mounting detection has been performed continuously a predetermined number of times (N times, for example, 5 times). The mounting detection shown in FIGS. 9A and 9B is performed in step S14-2 until the number of mounting detections reaches N times. When the placement detection is performed N times in succession, the process proceeds to step S14-3.

In step S14-3, the detection current Ds1 is supplied to the heating coils A1 and A2 during the on-time Ton1 during the detection period Dp1.

In step S14-4, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section A. This process detects a relatively large load, for example a pot with a diameter of about 150 mm or more.

When the result in step S14-4 is No, that is, when the load is not detected by the detection current Ds1, in step S14-5, the detection current is detected in the heating coils A1 and A2, and in the on-time Ton2 during the detection period Dp2. Ds2 is supplied.

In step S14-6, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section A. If the result in step S14-6 is No, in step S14-10, the load detection unit 10 determines that the load is not placed in the section A. The process proceeds to FIG. 14B.

On the other hand, when the result of step S14-4 or S14-6 is Yes, in step S14-7, the load detection unit 10 determines that the load is placed in the section A. In step S14-8, the load detection unit 10 determines whether or not the latest mounting detection result is the same as the result in the immediately preceding detection cycle.

If the result of step S14-8 is Yes, in step S14-9, the detection cycle for the section A is extended from the detection cycle T0 to the detection cycle T1. In this embodiment, the detection cycle T1 is 8 seconds. Then, the process proceeds to FIG. 14B. If the result of step S14-8 is No, the process proceeds to FIG. 14B.

In steps S14-11 to S14-18 of FIG. 14B, the same processing as in steps S14-3 to S14-10 is performed on the section B.

In step S14-11, the heating coils B1 and B2 are supplied with the detection current Ds1 during the on-time Ton1 during the detection period Dp1.

In step S14-12, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section B.

When the result in step S14-12 is No, that is, when the load is not detected by the detection current Ds1, in step S14-13, the detection current is detected in the heating coils B1 and B2, and in the on-time Ton2 during the detection period Dp2. Ds2 is supplied.

In step S14-14, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section B.

If the result in step S14-14 is No, that is, if the load is not detected even at the detection current Ds2, in step S14-18, the load detection unit 10 determines that the load is not placed in the section B. .. Then, the process proceeds to step S14-19.

On the other hand, when the result of step S14-12 or S14-14 is Yes, that is, when the load is detected by the detection current Ds1 or Ds2, in step S14-15, the load detection unit 10 puts a load on the compartment B. Judge that it is mounted. In step S14-16, the load detection unit 10 determines whether or not the latest mounting detection result is the same as the result in the immediately preceding detection cycle.

If the result of step S14-16 is Yes, in step S14-17, the detection cycle for the section B is extended from the detection cycle T0 to the detection cycle T1. Then, the process proceeds to step S14-19. If the result of step S14-16 is No, the process proceeds to step S14-19.

Placement detection is performed in step S14-19. In step S14-20, the load detection unit 10 determines whether or not there is a change in the mounting state with respect to another heating region, for example, the central heating region Ch.

If the result of step S14-20 is No, the imposition detection is performed every determined detection cycle. If the result of step S14-20 is Yes, in step S14-21, the drive control unit 11 sets the detection cycle to the detection cycle T0. That is, when the detection cycle is set to the detection cycle T1, the detection cycle is returned to the detection cycle T0.

According to the change of the detection cycle of the present embodiment, as a result of the mounting detection performed every detection cycle T0, the load detection unit 10 continuously loads the load in the compartment A or B N times (for example, 5 times). If it is determined that the drive control unit 11 is installed, the drive control unit 11 extends the detection cycle for the heating coil in the section from the detection cycle T0 to the detection cycle T1.

In the change of the detection cycle of the present embodiment, the placement detection is executed for each of the extended detection cycles T1 for the section on which the load is placed. For the section where the load is not placed, the placement detection is executed every detection cycle T0.

After the detection cycle is changed, when the load detection unit 10 newly detects the load placement in another heating region (for example, the central heating region Ch) where the load is not placed, the drive control unit 11 causes the drive control unit 11. The detection cycle set in the detection cycle T1 is reset to the detection cycle T0.

According to the change of the detection cycle of the present embodiment, the frequency of the placement detection is reduced for the already recognized load. As a result, it is possible to suppress heat generation of the load due to the detection current.

When a plurality of heating coils are driven by one drive unit via the switching unit, the switching operation of the switching unit can be reduced. This makes it possible to suppress the generation of sound when switching relays.

As described in the first embodiment, for example, when a load is placed above the heating coil A1 and no load is placed above the heating coil A2, the relay 8b is turned off and the heating coil A2 is placed. Is disconnected from the inverter 9.

However, also in this case, the relay 8b may be turned on to connect the heating coil A2 to the inverter 9, and the detection cycle for the heating coil A2 may be extended in the same manner as the detection cycle for the heating coil A1. This makes it possible to suppress the generation of sound when switching relays.

According to this embodiment, it is possible to quickly identify the heating coil to be operated when the load moves.

The above is a description of the change of the detection cycle when the load moves in the heating region (here, the left heating region Lh). When the load placed on the heating region is removed and when the load is added to the heating region, the detection cycle is changed in the same manner.

(Embodiment 4)
Hereinafter, determination of the placement status in the induction heating cooker according to the fourth embodiment of the present disclosure will be described. According to the present embodiment, in the same configuration as that of the first embodiment shown in FIGS. 1 to 5, in addition to the load detection shown in FIGS. 7A to 11, 14A, and 14B, the mounting status is determined. Will be.

[Confirmation of placement status]
The concept of determining the placement status in the present embodiment will be described using the induction heating cooker shown in FIG. 13A, as in the case of changing the detection cycle.

FIG. 15A is a timing chart for explaining the concept of determining the placement status according to the fourth embodiment.

The upper half of FIG. 15A shows the detection periods Dpa1 to Dpd1, Dpa2 to Dpd2, Dpa3 to Dpd3, in which the mounting detection is performed on the heating coils 31 to 34 in the detection cycles T (a) to T (d), respectively. The periods Dpa4 to Dpd4 are shown. The length of each of the detection cycles T (a) to T (d) is equal to the above-mentioned detection cycle T0.

In these detection periods, the load detection unit 10 determines whether or not the load is mounted above the heating coils 31 to 34, similarly to the mounting detection performed in the detection period Dp1 shown in FIG. 12A.

The lower half of FIG. 15A shows the temporal change of the mounting state above the heating coil 31 to the heating coil 34. FIG. 15B shows a pattern of mounting conditions of loads (pots La, Lb, Lc) above the heating coils 31 to 34.

As shown in FIG. 15B, in the state Sa, the pan La is placed above the heating coils 33 and 34. In the state Sb, the pan La is placed above the heating coils 32, 33 and 34. In the state Sc, the pan Lb is placed above the heating coils 33 and 34. In the state Sd, the pot Lb is placed above the heating coils 33 and 34, and the pot Lc is placed above the heating coil 32.

As shown in the lower half of FIG. 15A, the determination of the placement status in the case of “state Sa → state Sb” and the case of “state Sc → state Sd” will be described.

The “state Sa → state Sb” is a case where the mounting state changes from the state Sa to the state Sb by slightly shifting the pot La. "State Sc-> state Sd" is a case where the placement state changes from the state Sc to the state Sd due to the addition of the pot Lc to the situation where the pot Lb is placed.

First, the determination of the placement status in the case of "state Sa → state Sb" will be described.

In the detection cycle T (a), the load detection unit 10 detects that the pot La is placed like the state Sa in the detection period Dpa3 for the heating coil 33 and the detection period Dpa4 for the heating coil 34. .. Based on this result, the load detection unit 10 tentatively determines that the mounting status is the state Sa.

In the detection cycle T (b), the detection period Dpb2 for the heating coil 32, the detection period Dpb3 for the heating coil 33, and the detection period Dpb4 for the heating coil 34, the load detection unit 10 has the pan La as in the state Sb. Detects that it is mounted. Based on this result, the load detection unit 10 tentatively determines again that the mounting state is the state Sb.

When the result of the mounting detection in the detection cycle T (c) is the same as the detection cycle T (b), the load detection unit 10 determines that the mounting status is the state Sb. If not, the load detection unit 10 tentatively determines the mounting condition again.

Next, the determination of the placement status in the case of “state Sc → state Sd” will be described.

In the detection cycle T (a), the load detection unit 10 detects that the pot La is placed like the state Sc in the detection period Dpa3 for the heating coil 33 and the detection period Dpa4 for the heating coil 34. .. Based on this result, the load detection unit 10 tentatively determines that the mounting status is the state Sc.

In the detection cycle T (b), when the load detection unit 10 confirms that the mounting status does not change and the state Sc continues, it determines that the mounting status is the state Sc.

In the detection cycle T (c), the detection result in the detection period Dpc2 for the heating coil 32 changes. Based on this result, the load detection unit 10 tentatively determines that a new load has been placed above the heating coil 32 in addition to the determined state Sc.

In the detection cycle T (d), when the load detection unit 10 confirms that the detection result for the heating coil 32 does not change in the detection period and the same state continues, a new load is placed above the heating coil 32. Confirm that it has been placed. As a result, it is confirmed that the placement status is the state Sd.

According to the determination of the mounting status according to the present embodiment, when the change in the mounting status is tentatively determined in the detection cycle in which the change in the mounting status is first detected, and the same detection result is continuously obtained in the subsequent detection cycle. , Change the tentative decision to final. Not limited to this, the tentative decision may be changed to final when the same detection result is continuously obtained in at least one detection cycle following the tentative decision.

Hereinafter, the determination of the mounting state when the above concept is applied to the induction heating cooker having the circuit configuration shown in FIG. 5 will be described.

In the present embodiment, the treatment in the left heating region Lh in the compartment A and the compartment B will be described as in the case of the first to third embodiments. The same treatment is performed in parallel in the right heating region Rh and the central heating region Ch.

16A and 16B are flowcharts for determining the mounting state in the first detection cycle after the induction heating device is started, for example.

17A to 17C are flowcharts for determining the mounting status in the second and subsequent detection cycles following the detection cycle in which the processes shown in FIGS. 16A and 16B are performed.

16A and 16B, steps S16-1 to S16-14, are the same as steps S9-1 to S9-14 of FIGS. 9A and 9B in the mounting detection according to the first embodiment. Therefore, the description of steps S16-1 to S16-14 will be omitted, and the steps after step S16-14 will be described.

In step S16-15, if the result of the processing in steps S16-1 to S16-14 is "a load is placed on the compartment A", the processing proceeds to step S16-16. If not, the process proceeds to step S16-18.

In steps S16-16, the detection currents Ds3 are sequentially and individually supplied to the heating coils A1 and A2. The load detection unit 10 identifies the position in the compartment A by determining whether or not a load is placed above each of the heating coils A1 and A2 in the compartment A.

In step S16-17, the load detection unit 10 tentatively determines the mounting state, which is the result of the position identification in the section A.

The determination for position identification in steps S16-16 is the same as in the first embodiment, that is, the detection values of the input current detector 13 and the output current detector 14, and / or the input current detector 13 and the output current detector. It is performed based on the change of two consecutive detection values in each of the fourteen.

In steps S16-18 to S16-20, the same processing as in steps S16-15 to S16-17 for the compartment A is performed for the compartment B. In this way, the placement status in the compartments A and B is tentatively determined.

In the second and subsequent detection cycles following the first detection cycle in which the processes shown in FIGS. 16A and 16B are performed, the processes shown in FIGS. 17A to 17C are repeatedly performed.

In step S17-1 of FIG. 17A, the off relay (if any) of the relays 8a and 8b of the compartment A is turned on, and the heating coils A1 and A2 are connected to the inverter 9 of the compartment A. In step S17-2, the off relay (if any) of the relays 8a and 8b in the compartment B is turned on, and the heating coils B1 and B2 are connected to the inverter 9 in the compartment B.

In step S17-3, the detection current Ds1 is supplied to the heating coils A1 and A2 during the on-time Ton1 during the detection period Dp1.

In step S17-4, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section A. With this process, it is possible to detect a relatively large load, for example, a pot having a diameter of about 150 mm or more.

When the result in step S17-4 is No, that is, when the load is not detected by the detection current Ds1, in step S17-5, the detection current is detected in the heating coils A1 and A2, and in the on-time Ton2 during the detection period Dp2. Ds2 is supplied.

In step S17-6, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section A. If the result in step S17-6 is No, in step S17-10, the load detection unit 10 determines that the load is not placed in the section A. The process proceeds to FIG. 17B.

On the other hand, when the result of step S17-4 or step S17-6 is Yes, in step S17-7, the load detection unit 10 determines that the load is placed on the section A. In step S17-8, the load detection unit 10 determines whether or not the latest mounting detection result is the same as the result in the immediately preceding detection cycle.

If the result of step S17-8 is Yes, in step S17-9, the load detection unit 10 determines the mounting status in the section A. The process proceeds to FIG. 17B. If the result of step S17-8 is No, the process proceeds to FIG. 17B.

In steps S17-11 to S17-18 of FIG. 17B, the same processing as in steps S17-3 to S17-10 of FIG. 17A for the compartment A is performed for the compartment B.

In step S17-11, the heating coils B1 and B2 are supplied with the detection current Ds1 during the on-time Ton1 during the detection period Dp1.

In step S17-12, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section B.

When the result in step S17-12 is No, that is, when the load is not detected by the detection current Ds1, in step S17-13, the detection current is detected in the heating coils B1 and B2, and in the on-time Ton2 during the detection period Dp2. Ds2 is supplied.

In step S17-14, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section B.

If the result in step S17-14 is No, that is, if the load is not detected even at the detection current Ds2, in step S17-18, the load detection unit 10 determines that the load is not placed in the section B. .. The process proceeds to FIG. 17C.

On the other hand, when the result of step S17-12 or step S17-14 is Yes, that is, when the load is detected by the detection current Ds1 or Ds2, in step S17-15, the load detection unit 10 loads on the section B. Is determined to be placed. In step S17-16, the load detection unit 10 determines whether or not the latest mounting detection result is the same as the result in the immediately preceding detection cycle.

If the result of step S17-16 is Yes, in step S17-17, the load detection unit 10 determines the mounting status in the section B. The process proceeds to FIG. 17C. If the result of step S17-16 is No, the process proceeds to FIG. 17C.

As shown in FIG. 17C, in step S17-19, if the result of the determination of the placement status shown in FIG. 17A is “the placement status in the section A has been determined”, the process proceeds to step S17-23. .. If not, the process proceeds to step S17-20.

In step S17-20, if the result of determining the placement status shown in FIG. 17A is "a load is placed on the section A", the process proceeds to step S17-21. If not, the process proceeds to step S17-23.

In step S17-21, the detection currents Ds3 are sequentially and individually supplied to the heating coils A1 and A2. The load detection unit 10 identifies the position in the compartment A by determining whether or not a load is placed above each of the heating coils A1 and A2 in the compartment A.

In step S17-22, the load detection unit 10 tentatively determines the mounting state, which is the result of the position identification in the section A.

In steps S17-23 to S17-26, the same processing as in steps S17-19 to S17-22 for the compartment A is performed for the compartment B. In this way, the determination of the mounting status in the second and subsequent detection cycles is completed. After the next detection cycle, the processes shown in FIGS. 17A to 17C are repeated.

According to the determination of the mounting status of the present embodiment, the load is mounted above the heating coil adjacent to the heating coil on which the load is mounted by the time when a predetermined number of detection cycles elapse. When is detected, the load detection unit 10 determines that it is due to the movement of the load. When a similar change is detected after a period longer than a predetermined number of detection cycles has elapsed, the load detection unit 10 determines that it is due to the fact that another load is placed.

In this way, the induction heating cooker of the present embodiment can determine the loading status of the load.

According to the determination of the mounting status of the present embodiment, after the load detection and the provisional determination or determination for the mounting status are performed in the compartment A, the load detection in the compartment B and the provisional determination or determination for the mounting status are performed. Confirmation is done.

However, it is not limited to this. For example, after the load is detected in both the compartments A and B, a tentative determination or determination may be made for the placement status in the compartments A and B.

After the load is detected not only in the left heating region Lh but also in all the heating regions H, a tentative determination or determination may be made for the placement status.

According to the determination of the mounting status of the present embodiment, when the load is mounted over a plurality of heating regions, the load detecting unit 10 can detect the loading status of the load more accurately. .. As a result, the drive control unit 11 can induce and heat the load by operating an appropriate heating coil corresponding to the mounting situation.

(Embodiment 5)
Hereinafter, the induction heating cooker according to the fifth embodiment of the present disclosure will be described with reference to FIGS. 18A to 22B.

The induction heating cooker of the present embodiment has the same configuration as that of the first embodiment shown in FIGS. 1 to 5. The induction heating cooker of the present embodiment relates to the mounting detection according to the first embodiment, the position identification according to the second embodiment, the change of the detection cycle according to the third embodiment, and the fourth embodiment. Confirm the placement status and execute in order.

In the present embodiment, the treatment in the left heating region Lh in the compartment A and the compartment B will be described as in the case of the first to fourth embodiments. The same treatment is performed in parallel in the right heating region Rh and the central heating region Ch.

18A and 18B are flowcharts for mounting detection according to the present embodiment. The mounting detection shown in steps S18-1 to S18-14 of FIGS. 18A and 18B is the same as the mounting detection of the first embodiment shown in steps S9-1 to S9-14 of FIGS. 9A and 9B. Therefore, the description of FIGS. 18A and 18B will be omitted.

19A and 19B are flowcharts for specifying a position according to the present embodiment. The position specification shown in steps S19-1 to S19-8 of FIG. 19A is the same as the position specification according to the second embodiment shown in FIG. 12B. Therefore, the description of FIG. 19A will be omitted.

In step S19-9 of FIG. 19B, if the positioning result shown in FIG. 19B is "a load is placed above at least one of the heating coils A1 and A2", the process proceeds to step S19-10. .. If not, the process proceeds to step S19-11.

In step S19-10, the load detection unit 10 tentatively determines the mounting status in the section A.

In step S19-11, if the positioning result shown in FIG. 19B is "a load is placed above at least one of the heating coils B1 and B2", the process proceeds to step S19-12. If not, the process proceeds to FIG. 20A.

In step S19-12, the load detection unit 10 tentatively determines the mounting status in the section B. The process proceeds to FIG. 20A.

20A, 20B, and 21 are flowcharts for determining the mounting status according to the present embodiment.

The determination of the mounting status shown in steps S20-1 to S20-18 of FIGS. 20A and 20B is the determination of the mounting status according to the fourth embodiment shown in steps S17-1 to S17-18 of FIGS. 17A and 17B. Is the same as. Therefore, the description of FIGS. 20A and 20B will be omitted.

As shown in FIG. 21, in step S21-1, if the result of determining the placement status shown in FIG. 20A is "the placement status in section A has been determined", the process proceeds to step S21-6. .. If not, the process proceeds to step S21-2.

In step S21-2, if the result of determining the placement status shown in FIG. 20B is "the placement status in section B has been determined", the process proceeds to step S21-3. If this is not the case, the load detection unit 10 concludes that "the placement status has not been determined in the compartments A and B" and ends the determination of the placement status. In order to specify the position again, the process returns to step S19-1 of FIG. 19A.

In step S21-3, if the result of the process shown in FIG. 20A is "a load is placed on the section A", the process proceeds to step S21-4. If this is not the case, the load detection unit 10 concludes that "the loading status is determined in the compartment B and the load is not mounted on the compartment A", and the determination of the loading status is completed. The process proceeds to FIG. 22A.

In step S21-4, the detection currents Ds3 are sequentially and individually supplied to the heating coils A1 and A2. The load detection unit 10 determines whether or not a load is placed above each of the heating coils A1 and A2.

In step S21-5, the load detection unit 10 concludes that "the mounting status is determined in the compartment B and the mounting status is tentatively determined in the compartment A", and the determination of the mounting status is completed. The process proceeds to FIG. 22A.

In step S21-6, when the result of the process shown in FIG. 20B is "the placement status in the compartment B is determined", the load detection unit 10 "determines the placement status in the compartments A and B". We conclude that we have completed the determination of the placement status. The process proceeds to FIG. 22A. If not, the process proceeds to step S21-7.

In step S21-7, if the result of determining the placement status shown in FIG. 20B is "a load is placed on the section B", the process proceeds to step S21-8. If this is not the case, the load detection unit 10 concludes that "the loading status is determined in the compartment A and the load is not mounted on the compartment B", and the determination of the loading status is completed. The process proceeds to FIG. 22A.

In step S21-8, the detection currents Ds3 are sequentially and individually supplied to the heating coils B1 and B2. The load detection unit 10 determines whether or not a load is placed above each of the heating coils B1 and B2.

In step S21-9, the load detection unit 10 concludes that "the mounting status is determined in the section A and the mounting status is tentatively determined in the section B", and the determination of the mounting status is completed. The process proceeds to FIG. 22A.

As described above, in the second detection cycle, after the placement status shown in FIGS. 20A, 20B, and 21 is confirmed, in the third and subsequent detection cycles, the detection cycles shown in FIGS. 22A and 22B are executed. The changes will be executed.

22A and 22B are flowcharts for changing the detection cycle according to the present embodiment.

As shown in FIGS. 22A and 22B, in step S22-1, the drive control unit 11 determines whether or not the mounting detection has been performed continuously a predetermined number of times (N times, for example, 5 times). The process returns to step S20-1 in FIG. 20A until the number of placement detections reaches N times. When the placement detection is performed N times in succession, the process proceeds to step S22-2.

In step S22-2, the off relay (if any) of the relays 8a and 8b of the compartment A is turned on, and the heating coils A1 and A2 are connected to the inverter 9 of the compartment A. In step S22-3, the off relay (if any) of the relays 8a and 8b in the compartment B is turned on, and the heating coils B1 and B2 are connected to the inverter 9 in the compartment B.

In step S22-4, the detection current Ds1 is supplied to the heating coils A1 and A2 during the on-time Ton1 during the detection period Dp1.

In step S22-5, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section A. This process detects a relatively large load, for example a pot with a diameter of about 150 mm or more.

When the result in step S22-5 is No, that is, when the load is not detected by the detection current Ds1, in step S22-6, the detection current is detected in the heating coils A1 and A2, and in the on-time Ton2 during the detection period Dp2. Ds2 is supplied.

In step S22-7, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section A. If the result in step S22-7 is No, in step S22-11, the load detection unit 10 determines that the load is not placed in the section A. The process proceeds to FIG. 22B.

On the other hand, when the result of step S22-5 or S22-7 is Yes, in step S22-8, the load detection unit 10 determines that the load is placed on the section A. In step S22-9, the load detection unit 10 determines whether or not the latest mounting detection result is the same as the result in the immediately preceding detection cycle.

If the result of step S22-9 is Yes, in step S22-10, the detection cycle for the compartment A is extended from the detection cycle T0 to the detection cycle T1. In this embodiment, the detection cycle T1 is 8 seconds. Then, the process proceeds to FIG. 22B. If the result of step S22-9 is No, the process proceeds to FIG. 22B.

In steps S22-12 to S22-19 of FIG. 22B, the same processing as in steps S22-4 to S22-11 is performed on the section B.

In steps S22-12, the heating coils B1 and B2 are supplied with the detection current Ds1 during the on-time Ton1 during the detection period Dp1.

In step S22-13, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section B.

When the result in step S22-13 is No, that is, when the load is not detected by the detection current Ds1, in step S22-14, the detection current is detected in the heating coils B1 and B2, and in the on-time Ton2 during the detection period Dp2. Ds2 is supplied.

In step S22-15, the load detection unit 10 makes the same determination as in step S9-4 of FIG. 9A with respect to the detection values of the input current detector 13 and the output current detector 14 in the section B.

If the result in step S22-15 is No, that is, if the load is not detected even at the detection current Ds2, in step S22-19, the load detection unit 10 determines that the load is not placed in the section B. .. Then, the process proceeds to step S22-20.

On the other hand, when the result of step S22-13 or S22-15 is Yes, that is, when the load is detected by the detection current Ds1 or Ds2, in step S22-16, the load detection unit 10 puts a load on the section B. Judge that it is mounted. In step S22-17, the load detection unit 10 determines whether or not the latest mounting detection result is the same as the result in the immediately preceding detection cycle.

If the result of step S22-17 is Yes, in step S22-18, the detection cycle for the section B is extended from the detection cycle T0 to the detection cycle T1. Then, the process proceeds to step S22-20. If the result of step S22-17 is No, the process proceeds to step S22-20.

Placement detection is performed in step S22-20. In step S22-21, the load detection unit 10 determines whether or not there is a change in the mounting state with respect to another heating region, for example, the central heating region Ch.

If the result of step S22-21 is No, the imposition detection is performed every determined detection cycle. If the result of step S22-21 is Yes, in step S22-22, the drive control unit 11 sets the detection cycle to the detection cycle T0. That is, when the detection cycle is set to the detection cycle T1, the detection cycle is returned to the detection cycle T0.

In the present embodiment, when it is detected that a load is placed in the section A, a provisional determination or determination is made for the placement status in the section A. Subsequently, when it is detected that a load is mounted in the compartment B, a provisional determination or determination is made for the loading status in the compartment B.

However, when the load detection in the compartments A and B is completed, the placement status in the compartments A and B may be tentatively determined or confirmed.

When the load detection in all the heating regions H as well as the left heating region L is completed, the placement status in all the heating regions H may be tentatively determined or confirmed.

As a result, when the load is mounted over a plurality of sections, the loading status of the load can be accurately detected.

The present disclosure is applicable to a multi-coil type induction heating device having a large number of heating coils provided below the top plate.

1 Housing 2 Top plate 3,31,32,33,34, A1, A2, B1, B2 Heating coil 4 Drive unit 5 Operation display unit 6 Infrared sensor 7 Thermista 8 Switching unit 8a, 8b, 25 Relay 9 Inverter 10 Load Detection unit 11 Drive control unit 12 Commercial power supply 13 Input current detector 14, 23 Output current detector 15 Diode bridge 16 Chalk coil 17 Condenser 18 Filter circuit 19a, 19b Switching element 20 Snubber capacitor 21a, 21b, 21c, 21d Resonant capacitor 22 Input voltage detector 24 Clamp capacitor 50 Control unit

Claims (5)

A top plate configured to carry the load, and
A plurality of heating coils provided below the top plate, and
At least one drive unit configured to supply high frequency power to the plurality of heating coils, and
An electric signal detection unit configured to detect an electric signal related to an element included in the drive unit, and an electric signal detection unit.
A control unit configured to input the electric signal and control the drive unit,
Equipped with
The control unit controls at least one drive unit so that the detection current, which is the high-frequency power, is repeatedly supplied to the plurality of heating coils at a predetermined detection cycle, and the electric signal responds to the detection current. Based on this, it is configured to detect the loading of the load above the plurality of heating coils.
When the control unit detects the loading of the load above any one of the plurality of heating coils, the control unit is configured to tentatively determine the loading status of the load.
The control unit
(1) In the second detection cycle after the first detection cycle in which the tentative determination is made, the placement of the load is detected above the heating coil related to the tentatively determined previously described placement situation. In addition, when the placement of a new load is not detected above the heating coil adjacent to the heating coil related to the tentatively determined pre-statement status, the tentatively determined pre-statement status is determined. And is configured as
(2) In the second detection cycle, the loading of the load is detected above the heating coil related to the tentatively determined pre-described state, and the tentatively determined pre-described state is set. When a new load is detected above the heating coil adjacent to the related heating coil, it is determined that the load has moved, and the mounting status in the second detection cycle is tentatively determined again. Induction heating device configured as such. In the second detection cycle, the load is detected above the heating coil related to the tentatively determined pre-described state, and the tentatively determined pre-described state is related to the above-mentioned. When a new load is detected above the heating coil adjacent to the heating coil, it is determined that the load has moved, and the mounting status in the second detection cycle is tentatively determined again. Being done
In the third detection cycle after the second detection cycle, the loading of the load is detected above the heating coil related to the previously described setting condition that has been tentatively determined again, and the load is tentatively determined again. If no new load is detected above the heating coil adjacent to the heating coil related to the pre-statement status, the pre-statement status that has been tentatively determined is determined again. The induction heating device according to claim 1. The top plate has at least one heating region and has
The at least one heating region has a plurality of compartments and
The induction heating device according to claim 1, wherein the plurality of heating coils and the at least one driving unit are provided for one of the plurality of compartments. A step of repeatedly supplying a detection current, which is high-frequency power, to a plurality of heating coils provided below the top plate at a predetermined detection cycle.
A step of detecting the loading of the load above the plurality of heating coils based on the electric signal in response to the detected current, and a step of detecting the load.
When the loading of the load is detected above any one of the plurality of heating coils, the step of provisionally determining the loading status of the load and the step of determining the loading status of the load.
(1) In at least one second detection cycle following the first detection cycle in which the tentative determination is made, the load is placed above the heating coil related to the tentatively determined previously described placement situation. If the loading of the load is not detected above the heating coil adjacent to the heating coil that is detected and related to the tentatively determined pre-statement status, the tentatively determined pre-statement status is determined.
(2) In the second detection cycle, the loading of the load is detected above the heating coil related to the tentatively determined pre-described state, and the tentatively determined pre-described state is set. When a new load is detected above the heating coil adjacent to the related heating coil, it is determined that the load has moved, and the mounting status in the second detection cycle is tentatively determined again. Load detection methods in induction heating devices, including steps. In the second detection cycle, the load is detected above the heating coil related to the tentatively determined pre-described state, and the tentatively determined pre-described state is related to the above-mentioned. When a new load is detected above the heating coil adjacent to the heating coil, it is determined that the load has moved, and the mounting status in the second detection cycle is tentatively determined again.
In the third detection cycle after the second detection cycle, no new load placement is detected above the heating coil adjacent to the heating coil related to the previously tentatively determined pre-described situation. In the case, the load detection method in the induction heating device according to claim 4, further comprising a step of determining the pre-described setting condition that has been tentatively determined again.

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