JPWO2018042820A1 - Induction heating apparatus and load detection method in induction heating apparatus - Google Patents

Abstract

In the multi-coil type induction heating apparatus, when the control unit (50) detects the placement of the load above any one of the heating coils (3), it temporarily determines the placement situation of the load. The control unit (50) sets the load when the placement of the load is detected in the next detection cycle above the heating coil (3) adjacent to the heating coil (3) related to the temporarily determined placement situation. Is determined to move, and the placement situation is tentatively determined again. The control unit (50) places the load on the heating coil (3) adjacent to the heating coil (3) related to the temporarily determined mounting situation in the detection cycle subsequent to the temporarily determined detection cycle If not detected, the temporarily determined placement situation is decided. The control unit (50) is configured such that the load in the determined placement situation is detected above the heating coil (3) adjacent to the heating coil (3) related to the determined placement situation Judge as different.

Description

  The present disclosure relates to an induction heating apparatus for induction heating 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. It relates to the device.

  In recent years, development of multi-coil induction heating cookers has been advanced. The multi-coil induction heating cooker includes a large number of heating coils arranged in a matrix below the top plate, and is configured to be able to change the heating region according to the situation (see Patent Documents 1 and 2).

Unexamined-Japanese-Patent No. 2008-293871 International Publication No. 2014/064931

  As described above, the multi-coil heating cookers disclosed in Patent Documents 1 and 2 detect the position of the load placed on the top plate and specify one or more heating coils to be operated. Do.

  This operation is performed by detecting a change in an electrical signal in an energization path which respectively connects the power supply of the heating cooker and each of the heating coils when a detection current which is high frequency power is supplied to the heating coils. Hereinafter, this work is called load detection.

  How to perform load detection accurately in a short time with energy saving is a problem to be solved in the development of a multi-coil type induction heating apparatus.

  One aspect of the present disclosure includes 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 electrical signal detection unit configured to detect an electrical signal related to an element included in the drive unit; a control unit configured to receive the detected electrical signal and control the drive unit; It is an induction heating apparatus provided with.

  In the induction heating apparatus according to this aspect, 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 placement of the load above the plurality of heating coils based on the electrical signal in response to the detection current.

  The control unit temporarily determines the placement condition of the load when the placement of the load is detected above any one of the plurality of heating coils. The control unit does not detect the placement of a new load above the heating coil adjacent to the heating coil related to the temporarily determined mounting situation in the detection cycle after the provisionally determined detection cycle. In this case, the temporarily determined placement situation is decided.

  Another aspect of the present disclosure is a load detection method in an induction heating device. The load detection method according to the present aspect is based on the steps 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 electrical signal responsive to the detection current Sensing the placement of the load above the plurality of heating coils.

  The load detection method according to the present aspect further includes the step of temporarily determining the load setting status when the load setting is detected above any one of the plurality of heating coils, and the detection in which the temporary determination is performed. If the placement of the load is not detected above the heating coil adjacent to the heating coil related to the temporarily determined mounting situation in at least one detection cycle following the cycle, the temporarily determined mounting situation is determined And step.

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

  According to a first aspect of the present disclosure, one aspect of the present disclosure provides a top plate on which a load is placed, a plurality of heating coils provided below the top plate, and high-frequency power to the plurality of heating coils. And at least one drive unit configured to be connected to the electric signal detection unit configured to detect an electric signal related to an element included in the drive unit; and the detected electric signal to control the drive unit And a control unit configured to:

  In the induction heating apparatus according to this aspect, 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 placement of the load above the plurality of heating coils based on the electrical signal in response to the detection current.

  The control unit temporarily determines the placement condition of the load when the placement of the load is detected above any one of the plurality of heating coils. The control unit does not detect the placement of a new load above the heating coil adjacent to the heating coil related to the temporarily determined mounting situation in the detection cycle after the provisionally determined detection cycle. In this case, the temporarily determined placement situation is decided.

  According to the induction heating device of the second aspect of the present disclosure, in the first aspect, the control unit performs the provisional determination above the heating coil adjacent to the heating coil related to the provisionally determined placement situation. When placement of a new load is detected in the detection cycle after the performed detection cycle, it is determined that the load has moved, and the placement situation in the detection cycle after the provisionally decided detection cycle is again determined. Make a tentative decision.

  The control unit places a new load on the heating coil adjacent to the heating coil related to the temporarily determined mounting situation again at the detection cycle after the detection cycle at which the temporary determination is performed again. If not detected, the provisionally determined placement situation is determined again.

  According to the induction heating device of the third aspect of the present disclosure, in the first aspect, the control unit performs provisional determination above the heating coil adjacent to the heating coil related to the provisionally determined placement situation. When the placement of a new load is detected in the detection cycle after the conducted detection cycle, it is determined that another load is placed, and the placement situation of the other load is tentatively determined, and the tentative decision is The placement situation in the performed detection cycle is determined.

  The control unit sets a new load above the heating coil adjacent to the heating coil related to the loading situation of the other load at the detection cycle after the sensing cycle in which the loading situation of the other load is temporarily determined. If the placement of the object is not detected, the temporarily determined placement situation is determined.

  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 area has a plurality of compartments. A plurality of heating coils and at least one drive are provided for one of the plurality of sections.

  A fifth aspect of the present disclosure is a load detection method in an induction heating device. The load detection method according to the present aspect is based on the steps 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 electrical signal responsive to the detection current Sensing the placement of the load above the plurality of heating coils.

  The load detection method according to the present aspect further includes the step of temporarily determining the load setting status when the load setting is detected above any one of the plurality of heating coils, and the detection in which the temporary determination is performed. If the placement of the load is not detected above the heating coil adjacent to the heating coil related to the temporarily determined mounting situation in at least one detection cycle following the cycle, the temporarily determined mounting situation is determined And step.

  According to the load detection method of the induction heating device of the sixth aspect of the present disclosure, in the fifth aspect, the provisional determination is performed above the heating coil adjacent to the heating coil related to the provisionally determined placement situation. When placement of a new load is detected in the detection cycle after the performed detection cycle, it is determined that the load has moved, and the placement situation in the detection cycle after the provisionally decided detection cycle is again determined. A new load is placed on the heating coil adjacent to the heating coil associated with the temporarily determined placement situation again in the step of provisionally determining and the detection cycle after the provisionally determined sensing cycle again. And if the placement situation is not detected, the step of determining the provisionally determined placement situation again.

  According to the load detection method of the induction heating device of the seventh aspect of the present disclosure, in the fifth aspect, the provisional determination is performed above the heating coil adjacent to the heating coil related to the provisionally determined placement situation. When the placement of a new load is detected in the detection cycle after the conducted detection cycle, it is determined that another load is placed, and the placement situation of the other load is tentatively determined, and the tentative decision is The step of determining the setting situation in the performed detection cycle, and the detection cycle after the detection cycle in which the setting situation of the other load is tentatively determined, to the heating coil related to the setting situation of the other load And determining, when not detecting the placement of a new load above the adjacent heating coil, determining the provisionally determined placement situation.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In all the following drawings, the same reference numerals are given to the same or corresponding parts, and duplicate explanations are omitted.

  The embodiments are all specific examples of the present disclosure. Numerical values, shapes, configurations, steps, order of steps, and the like described in the embodiments are merely examples, and do not limit the present disclosure.

  The present disclosure also includes configurations in which configurations according to some embodiments are appropriately combined. As such, the combined configuration provides all the benefits of the associated embodiment.

  Here, the induction heating cooker as an example of the induction heating apparatus of this indication is demonstrated. However, the present disclosure is not limited to induction heating cookers.

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

Embodiment 1
FIG. 1: is a disassembled perspective view which shows the induction heating cooker which is an induction heating apparatus which concerns on Embodiment 1 of this indication. FIG. 2 is a plan view of the induction heating cooker according to the present embodiment with the top plate removed.

  As shown in FIGS. 1 and 2, the induction heating cooker according to the present embodiment includes a housing 1, a top plate 2 covering an upper portion of the housing 1, and a plurality of heating units provided inside the housing 1. The coil 3 and the operation display unit 5 are provided.

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

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

  Four heating coils 3 are disposed below the left heating area Lh and the right heating area Rh, respectively. These heating coils are arranged in a line in the front-rear direction with the major axis of the oval shape being in the left-right direction.

  Three heating coils 3 are disposed below the central heating area Ch. These heating coils are arranged in a line in the left-right direction with the major axes of the ovals facing in the front-rear direction. A heating area H is constituted by the left heating area Lh, the right heating area Rh, and the central heating area Ch.

  In the present embodiment, the number of heating coils 3 provided in each of the left heating area Lh, the right heating area Rh, and the central heating area Ch is an example, and is not limited thereto. Although a plurality of heating coils 3 having an elliptical shape in plan view are used, a heating coil having a circular shape in plan view may be used. 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 track-like track shape.

  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 operates, 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 to detect the temperature of the load placed in the heating area H. Specifically, in the left heating area Lh and the right heating area 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 area Ch, a thermistor 7 is provided at the center of the heating coil 3 located at the center of the three heating coils 3. The thermistors 7 are respectively provided on the outer circumferences of the two heating coils 3 located at both ends of the three heating coils 3 respectively facing the left heating area Lh and the right heating area Rh. An infrared sensor 6 is provided between two adjacent heating coils 3.

  According to this configuration, even if the load is placed on the heating area H, the temperature of the load can be detected with high accuracy.

  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, the drive unit 4 and the like. And is provided. The drive unit 4 and the drive control unit 11 will be described later.

  FIG. 3 shows two sections (sections A and B) respectively included in the left heating area Lh, the right heating area Rh, and the central heating area Ch.

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

  In the central heating area Ch, the section A has the heating coil 3 at the right end of the three heating coils 3, ie, the heating coil A2. The section B has the remaining two heating coils 3, namely the heating coil B1 and the heating coil B2 disposed 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 driving units 4. In the section A of the central heating area Ch, one drive unit 4 drives one heating coil 3. In the other sections, one drive unit 4 drives the two heating coils 3 via the switching unit 8.

  FIGS. 4 and 5 are a functional block diagram and a circuit block diagram, respectively, regarding a section (for example, section A of the left heating area Lh) in which two heating coils 3 are driven by one drive unit 4.

  As shown in FIGS. 4 and 5, two heating coils 3 (heating coils A1 and A2) are connected in parallel. The switching unit 8 includes a relay 8 a and a relay 8 b which are controlled by the drive control unit 11 and connect or disconnect between each of the heating coils A 1 and A 2 and the drive unit 4. The relays 8a and 8b are configured by mechanical relays or semiconductor relays.

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

  The load detection unit 10 determines whether 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 a control unit 50.

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

  The diode bridge 15 rectifies 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 in series a switching element 19a disposed on the high voltage side and a switching element 19b disposed on the low voltage side. For example, IGBTs are used as the switching elements 19a and 19b. Reverse conduction diodes are connected in parallel to switching elements 19a and 19b, respectively. The inverter 9 is connected to both ends of the capacitor 17.

  The resonant capacitor 21a is connected in series to the heating coil A1, and constitutes a resonant circuit together with the heating coil A1. The resonant capacitor 21b is connected in series to the heating coil A2, and constitutes a resonant 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 19 b.

  The input current detector 13 is an electrical 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 electrical signal detection unit on the output side of the drive unit 4 that detects the current flowing through the inverter 9. These electrical signal detection units detect a voltage value, a current value, and a power value obtained by calculation.

  FIG. 6A is a circuit block diagram that is a first modification of the circuit block diagram shown in FIG. As shown in FIG. 6A, in the present modification, the drive unit 4 includes a resonant capacitor 21c instead of the resonant 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.

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

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

  The resonant capacitor 21c is connected in parallel to 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 constitutes another resonance circuit together with the heating coil A2.

  The input voltage detector 22 is an electrical 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 electrical 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 the load is placed on the top 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, a series body of a resonant capacitor 21d and a relay 25 in which the drive unit 4 is connected in parallel to the resonant capacitor 21c. Have.

  In the present modification, when both the relay 8 a and the relay 8 b are turned on, the drive control unit 11 turns on the relay 25. By connecting the resonant capacitor 21d in parallel with the resonant capacitor 21c, the combined capacitance of the resonant 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 area 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 area H and to specify the heating coil to be operated.

  Therefore, the induction heating cooker of the present embodiment periodically executes load detection after activation. Load detection includes placement detection and position determination. The placement detection means determining whether or not the load is placed somewhere in the heating area H, and the position specification identifies the heating coil 3 on which the load is placed on the upper side. It means that.

  Hereinafter, processing in the section A and the section B of the left heating area Lh will be described. The same processing is performed in parallel also in the right heating area Rh and the central heating area Ch.

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

  FIGS. 7A and 7B schematically show temporal changes in peak value of the amplitude of the detection current supplied to the heating coil 3 disposed in the sections A and B for detection of placement.

  As shown in FIG. 7A, in the detection period Dp1, the detection current Ds1 is supplied to the heating coil 3 disposed in the sections A and B. This makes it possible to detect relatively large loads, for example pans of about 150 mm or more in diameter.

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

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

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

  As shown in FIG. 8B, during the detection period Dp2, when the switching element 19b is turned on for the on time Ton2, a detection current Ds2 flows in 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 microseconds. The period for performing load detection (hereinafter, referred to as a detection period) 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 placement detection according to the present embodiment. The placement 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, placement detection starts. The induction heating cooker may have a proximity sensor so that placement detection starts when it is detected that a person approaches the vicinity of the induction heating cooker.

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

  Before placement detection is performed, all the relays in the left heating area 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) for the on time Ton1 which is the first predetermined time.

  In step S9-4, the load detection unit 10 performs a predetermined determination on the detection values of the input current detector 13 and the output current detector 14 of the section A.

  When 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.

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

  In step S9-6, the load detection unit 10 performs the same determination as in step S9-4 on 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. When 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 placement detection in steps S9-4 and S9-6 is performed based on the detection values of the input current detector 13 and the output current detector 14.

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

  When one of the detected values becomes equal to or greater than the threshold value, the load detecting unit 10 sets the load to an area equal to or greater than a predetermined ratio (for example, 40%) of the heating area H facing the heating coils A1 and A2. Is determined to occupy the

  In addition to or instead of the determination based on the detected value itself as described above, the determination for the placement detection is two consecutive detected 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 FIG. 6A and FIG. 6B, the determination for placement detection is the detection value of the input voltage detector 22 and the output current detector 23, and / or the input voltage detector 22, 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 in the detection period Dp2 is smaller than the load detected in the detection period Dp1. A small pan with a minimum diameter of 110 mm corresponds to the load detected in the detection period Dp2, but metal substances smaller than 100 mm × 20 mm × 1.0 mm (for example, a knife, a fork) are detected in the detection period Dp2. Does not correspond to the load.

  Next, the load detection unit 10 determines whether a load is placed in the section B. The placement detection for the section B is substantially the same as the placement detection for the section A.

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

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

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

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

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

  When the result in step S9-12 is Yes, the load detection unit 10 determines in step S9-13 that the load is placed on the section B. When 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 determinations in steps S9-10 and S9-12 are performed in the same manner as the determinations in steps S9-4 and S9-6.

  Since the placement detection is performed periodically, when a large high frequency current is used for placement detection, a large leakage magnetic field may be generated from the heating coil 3 on which no load is placed. In the heating coil 3 on which the load is placed, the load may be unnecessarily heated.

  According to the present 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 relatively large, the load can be accurately detected in a short time with energy saving. When the load is not detected by the detection current Ds1, by performing the placement detection again using the detection current Ds2, a small load can be detected to some extent.

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

[Positioning]
FIG. 10A is a timing chart for placement detection and position determination in sections A and B of the left heating area Lh. As shown in FIG. 10A, in the present embodiment, placement detection and position specification are repeatedly performed at a predetermined detection cycle T0. In the detection cycle T0, first, the placement detection described above is sequentially and individually performed on the sections A and B.

  Then, position specification is performed in order of heating coil A1 of division A, heating coil A2 of division A, heating coil A1 of division B, and heating coil A2 of division B. The switching unit 8 of the sections 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 a third detection current.

  After the supply of the detection current Ds3 to the heating coil A2, the relay 8b of the section A is kept on. After the supply of the detection current Ds3 to the heating coil B2, the relay 8b of the section B is kept on.

  In the present embodiment, the detection period Dp3 is 200 ms. The switching period of the switching elements 19a and 19b is 50 microseconds. 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 a 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 in the detection period Dp1 (see FIG. 10A) for performing placement detection. In FIG. 10B, the on time Ton1 is 5 microseconds, and the switching period of the switching elements 19a and 19b is 50 microseconds.

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

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

  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 area specification is completed before the on-time Ton3 reaches the maximum value, the increase of 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 a third predetermined time. The detection current Ds3 also increases in accordance with the increase of the on time Ton3.

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

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

  In step S11-2, the detection current Ds3 is sequentially and individually supplied to the heating coils A1 and A2. The load detection unit 10 specifies the position in the section A by determining whether a load is placed above each of the heating coils A1 and A2.

  The determination for position specification 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, the output current detection, as in the placement detection described above. It is performed based on the change of two consecutive detected values in each of the units 14.

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

  The operation display unit 5 causes the portion of the operation display area P corresponding to the placement condition of the load in the heating area H to emit light. This is a state where load detection has been completed for all the heating coils 3 before the start of induction heating. Hereinafter, the loading situation of load may be simply referred to as the loading situation.

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

  As a result, when the mounting condition changes in the portion of the heating area H where the load is mounted, the change can be detected. The change in the mounting status means that the load has been moved, removed or added.

  In a situation where heating coils A1 and A2 are both connected to inverter 9, for example, when a load is placed above heating coil A1 and no load is placed above heating coil A2, relay 8b is provided. 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 situation is determined. This is because, if this operation is performed immediately after the above-mentioned situation is detected, the heating coil A2 is disconnected from the inverter 9 simply by, for example, the user lifting the load and replacing it immediately.

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

  If the result is the same as before the change in the detected value is detected, the drive control unit 11 determines that there is no change in the mounting condition, and the switching unit 8 detects the change in the detected value before In the same state, that is, the heating coil A1 is disconnected from the inverter 9, and the heating coil A2 is returned to the state of connection to the inverter 9. This is because the change in the detected value is likely to be due to a slight movement of the load without the need to change the heating coil 3 to be operated.

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

  According to the present embodiment, the operations 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 noise 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 apparatus 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 a load is placed above the heating coils A1 and A2 based on the change of the electric signal.

  When the control unit 50 determines that no load is placed above the heating coils A1 and A2, the control unit 50 supplies high-frequency power and a detection current Ds2 having a larger current value than the detection current Ds1 to the heating coils A1 and A2. Control the drive unit 4 so that

  The control unit 50 determines whether a load is placed above the heating coils A1 and A2 based on the change of the electric signal.

  When the detection current Ds1 or Ds2 is supplied, the control unit 50 controls the switching unit 8 to connect all the heating coils A1 and A2 to the drive unit 4. The control unit 50 determines whether a load is placed above the heating coils A1 and A2 based on the change of 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. The drive unit 4 and the switching unit 8 are controlled. Control unit 50 determines whether a load is placed above each of heating coils A1 and A2.

  Further, according to the induction heating device of the present embodiment, the top 2 has the left heating area Lh, the central heating area Ch, and the right heating area Rh, and these heating areas have the sections A and B, The coils A1 and A2 and the drive unit 4 are provided for the section A of the sections A and B.

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

  Furthermore, according to the induction heating apparatus of the present embodiment, control unit 50 controls drive unit 4 and switching unit 8 to supply detection currents Ds1 and Ds2 to heating coils A1 and A2, respectively. Determines whether a load is placed above the heating coils A1 and A2 based on the change in the electrical signal.

  If the control unit 50 determines that the load is placed above the heating coils A1 and A2, the driving unit 4 and the switching unit 4 sequentially supply the detection current Ds3 to each of the heating coils A1 and A2 sequentially. The unit 8 is controlled to determine whether a load is placed above each of the heating coils A1 and A2.

  After the determination on each of the heating coils A1 and A2, the control unit 50 controls the switching unit 8 to connect the heating coils A1 and A2 to the drive unit.

  In the present embodiment, the microcomputer configures the load detection unit 10 and the drive control unit 11. Although the present disclosure is not limited thereto, a programmable microcomputer can be used to easily change the processing content and can increase the degree of freedom in design.

  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 configured by one or more elements. When each of the load detection unit 10 and the drive control unit 11 includes a plurality of elements, each item may correspond to one element. In this case, it can be considered that the plurality of elements correspond to the load detection unit 10 and the drive control unit 11, respectively.

Second Embodiment
Hereinafter, the position specification in the induction heating cooker of Embodiment 2 of this indication is demonstrated.

  The induction heating cooker of the present embodiment has the same configuration as that of the first embodiment, and performs the same placement detection as that of the first embodiment. The present embodiment is different from the first embodiment in that the position specification shown in FIGS. 12A and 12B is performed instead of the position specification 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, as in the case of the first embodiment, processing in the section A and the section B of the left heating area Lh will be described. The same processing is performed in parallel also in the right heating area Rh and the central heating area Ch.

[Modification of position specification]
FIG. 12A is a timing chart for placement detection and localization in sections A and B of the left heating area Lh. FIG. 12A differs from FIG. 10A only in the order of localization.

  That is, in FIG. 10A, the position specification is performed in the order of the heating coil A1, the heating coil A2, the heating coil B1, and the heating coil B2. However, in the present embodiment, as shown in FIG. 12A, the position specification is performed in the order of heating coil A1, heating coil B2, heating coil A2, and heating coil B1. The switching unit 8 of the sections 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 supply of the detection current Ds3 to the heating coil A2, the relay 8b of the section A is kept on. After the supply of the detection current Ds3 to the heating coil B1, the relay 8a of the section 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 position specification 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 "load is placed on 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 a load is placed above the heating coil A1.

  In step S12-3, when the result of the placement detection shown in FIG. 9A is "load is placed on 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 a load is placed above the heating coil B1.

  In step S12-5, when the result of the placement detection shown in FIG. 9A is "load is placed on 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 a load is placed above the heating coil A2.

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

  In step S12-8, the detection current Ds3 is supplied to the heating coil B1. The load detection unit 10 determines whether a load is placed above the heating coil B2. This completes the process of specifying the position.

  As in the first embodiment, determinations for position specification in steps S12-2, S12-4, S12-6, and S12-8 are the detection values of the input current detector 13 and the output current detector 14, and / Or, it is performed based on the change of two consecutive detected values in each of the input current detector 13 and the output current detector 14.

  By these determinations, localization in sections A and B is performed.

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

  As described above, after the supply of the detection current Ds3 to the heating coil A2, the relay 8b of the section A is kept on. After the supply of the detection current Ds3 to the heating coil B1, the relay 8a of the section B is kept on. Therefore, for example, when the 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 end of the position specification.

Third Embodiment
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 the first embodiment shown in FIGS. 1 to 5, in addition to the load detection shown in FIGS. 7A to 11, the change of the detection cycle is performed.

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

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

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

  In these detection periods, the load detection unit 10 detects whether a load is placed above the heating coils 31 to 34 as in the placement detection performed in the detection period Dp1 shown in FIG. 12A. .

  The lower half of FIG. 13B indicates whether 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, no detection period is provided in the detection cycles T (c) and T (d) for the heating coils 31 and 32, and a detection period is provided in the detection cycle T (e).

  That is, when the placement of the load is detected twice in a row, the detection cycle increases. In FIG. 13B, the detection cycle is extended to a detection cycle T1 which 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 for the heating coil 33 is performed. During a 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 the result, in the detection cycle T (g), the detection period is provided for the heating coils 31 to 34, and the placement detection is performed. That is, for the heating coils 31 and 32, the detection cycle which is 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 to perform placement detection. When placement of the load is detected twice in a row, no detection period is provided in the detection cycles T (i) and T (j) for the heating coils 32 and 33, but in the detection cycle T (k) A detection period is provided. That is, for the heating coils 32 and 33, the detection cycle is extended to a detection cycle T1 which is three times the detection cycle T0.

  According to the concept of changing the detection cycle, in the multi-coil induction heating cooker, the placement detection is performed for each heating cycle in which the placement of the load is detected above the heating coil. The load detection is performed in the detection cycle T0 with respect to the heating coil whose load has not been detected above the load.

  If it is detected that the load is placed above the heating coil in which the load was not placed, in the subsequent detection cycle, a detection period is provided for all the heating coils. That is, the detection cycle is shortened. In the heating coil in which the placement of the load is newly detected, if there is no change in the placement state thereafter, the detection cycle is again extended.

  According to the concept of changing the detection cycle, the frequency of placement detection is reduced with respect to the load that has already been recognized. Thereby, the heat generation of the load due to the detection current can be suppressed. 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 a detection period in the case of applying the said concept to the induction heating cooker of the circuit structure shown in FIG. 5 is demonstrated.

  In the present embodiment, as in the first and second embodiments, processing in the section A and the section B of the left heating region Lh will be described. The same processing is performed in parallel also in the right heating area Rh and the central heating area 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 performed after the load detection including the placement detection described above and the position specification described above if necessary.

  As shown in FIGS. 14A and 14B, in step S14-1, the drive control unit 11 determines whether placement detection has been performed a predetermined number of times (N times, for example, five times) continuously. The placement detection shown in FIGS. 9A and 9B is performed in step S14-2 until the number of placement detections is N times. If the placement detection is performed N times consecutively, the process proceeds to step S14-3.

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

  In step S14-4, the load detection unit 10 performs the same determination as in step S9-4 of FIG. 9A on the detection values of the input current detector 13 and the output current detector 14 of the section A. In this process, a relatively large load, for example a pan with a diameter of about 150 mm or more, is detected.

  If the result in step S14-4 is No, that is, no load is detected by the detection current Ds1, in step S14-5, the heating coils A1 and A2 detect the on-time Ton2 during the detection period Dp2 Ds2 is supplied.

  In step S14-6, the load detection unit 10 performs the same determination as in step S9-4 of FIG. 9A on the detection values of the input current detector 13 and the output current detector 14 of 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 on 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, the load detection unit 10 determines in step S14-7 that the load is placed on the section A. In step S14-8, the load detection unit 10 determines whether the result of the latest placement detection is the same as the result in the immediately preceding detection cycle.

  If the result of step S14-8 is YES, then in step S14-9, the detection cycle for section A is extended from detection cycle T0 to detection cycle T1. In the present 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 that of steps S14-3 to S14-10 is performed on the section B.

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

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

  If the result in step S14-12 is No, that is, no load is detected by the detection current Ds1, in step S14-13, the heating coils B1 and B2 detect the on-time Ton2 during the detection period Dp2 Ds2 is supplied.

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

  When the result in step S14-14 is No, that is, when the load is not detected even in the detection current Ds2, in step S14-18, the load detection unit 10 determines that the load is not placed on 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, the load detection unit 10 loads the load on the section B in step S14-15. It determines that it has been placed. In step S14-16, the load detection unit 10 determines whether the result of the latest placement detection is the same as the result in the immediately preceding detection cycle.

  If the result of step S14-16 is YES, then in step S14-17, the detection cycle for section B is extended from detection cycle T0 to 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.

  In step S14-19, placement detection is performed. 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 area, for example, the central heating area Ch.

  If the result of step S14-20 is No, placement detection is performed for each 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 placement detection performed every detection cycle T0, the load detection unit 10 loads the load in section A or B continuously N times (for example, 5 times). If it is determined that it is placed, the drive control unit 11 extends the detection cycle for the heating coil of 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 the section where the load is placed, at each extended detection cycle T1. For a section where no load is placed, placement detection is performed every detection cycle T0.

  After the change of the detection cycle, when the load detection unit 10 newly detects the placement of the load in another heating area (for example, the central heating area Ch) in which the load is not placed, the drive control unit 11 The detection cycle set to 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 placement detection is reduced with respect to the load that has already been recognized. Thereby, the heat generation of the load due to the detection current can be suppressed.

  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. As a result, it is possible to suppress the generation of the sound when switching the relay.

  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 turned on. Are 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 similarly to the detection cycle for the heating coil A1. As a result, it is possible to suppress the generation of the sound when switching the relay.

  According to the present embodiment, when the load is moved, the heating coil to be operated can be identified quickly.

  The above is the description of the change of the detection cycle when the load moves in the heating area (here, the left heating area Lh). Even when the load placed on the heating area is removed and when the load is added to the heating area, the change of the detection cycle is similarly performed.

Embodiment 4
Hereinafter, determination of the mounting condition 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 the first embodiment shown in FIGS. 1 to 5, in addition to the load detection shown in FIG. 7A to FIG. 11, FIG. It will be.

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

  FIG. 15A is a timing chart for illustrating the concept of determination of the mounting state according to the fourth embodiment.

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

  In these detection periods, the load detection unit 10 determines whether a load is placed above the heating coils 31 to 34 as in the placement detection performed in the detection period Dp1 shown in FIG. 12A.

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

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

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

  “State Sa → state Sb” is a case where the placement state changes from the state Sa to the state Sb by slightly shifting the pan La. The “state Sc → state Sd” is a case where the placement state changes from the state Sc to the state Sd because the pan Lc is added to the state in which the pan Lb is placed.

  First, determination of the mounting state in the case of “state Sa → state Sb” will be described.

  The load detection unit 10 detects that the pan La is placed as in the state Sa in the detection period Dpa3 for the heating coil 33 and the detection period Dpa4 for the heating coil 34 in the detection cycle T (a). . Based on the result, the load detection unit 10 tentatively determines that the placement situation is the state Sa.

  In the detection cycle T (b), in 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 sets the pot La like the state Sb. It detects that it is placed. Based on the result, the load detection unit 10 tentatively determines again that the placement status is the state Sb.

  If the result of placement detection in the detection cycle T (c) is the same as the detection cycle T (b), the load detection unit 10 determines that the placement status is the state Sb. If this is not the case, the load detection unit 10 temporarily determines again the placement situation.

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

  The load detection unit 10 detects that the pan 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 in the detection cycle T (a). . Based on the result, the load detection unit 10 tentatively determines that the mounting condition is the state Sc.

  In the detection cycle T (b), the load detection unit 10 confirms that the placement situation is the state Sc when confirming that the placement situation does not change and the state Sc continues.

  In the detection cycle T (c), a change occurs in the detection result of the heating coil 32 in the detection period Dpc2. Based on this result, the load detection unit 10 temporarily 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 in the detection period for the heating coil 32 has no change and confirms that the same state continues, a new load is placed above the heating coil 32. Confirm that it has been placed. Thus, it is determined that the placement status is the state Sd.

  According to the determination of the placement situation according to the present embodiment, the change of the placement situation is temporarily determined in the detection cycle detected first, and the same detection result is continuously obtained in the subsequent detection cycle. , Change the tentative decision to final. The present invention is not limited to this, and the temporary determination may be changed to definite if the same detection result is continuously obtained in at least one subsequent detection cycle after the temporary determination.

  Hereinafter, determination of the mounting condition in the case where the said concept is applied to the induction heating cooker of the circuit structure shown in FIG. 5 is demonstrated.

  In the present embodiment, as in the first to third embodiments, processing in the section A and the section B of the left heating area Lh will be described. The same processing is performed in parallel also in the right heating area Rh and the central heating area Ch.

  FIG. 16A and FIG. 16B are flowcharts for determination of the mounting condition in the first detection cycle, for example, after the induction heating apparatus is activated.

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

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

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

  In step S16-16, the detection current Ds3 is sequentially and individually supplied to the heating coils A1 and A2. The load detection unit 10 specifies the position in the section A by determining whether a load is placed above each of the heating coils A1 and A2 of the section A.

  In step S <b> 16-17, the load detection unit 10 tentatively determines the mounting situation which is the result of the position specification in the section A.

  As in the first embodiment, the determination for position specification in step S16-16 is the detection values of the input current detector 13 and the output current detector 14, and / or the input current detector 13, the output current detector. It is performed based on the change of two consecutive detected values in each of 14.

  In steps S16-18 to S16-20, the same processing as that in steps S16-15 to S16-17 is performed on the section B. In this manner, the placement situation in the sections A and B is tentatively determined.

  In the second and subsequent detection cycles subsequent to 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 relay (if any) of the relays 8a and 8b of section A is turned on, and the heating coils A1 and A2 are connected to the inverter 9 of section A. In step S17-2, the relay (if any) of the relays 8a and 8b of the compartment B is turned on, and the heating coils B1 and B2 are connected to the inverter 9 of the compartment B.

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

  In step S17-4, the load detection unit 10 performs the same determination as in step S9-4 in FIG. 9A on the detection values of the input current detector 13 and the output current detector 14 in section A. In this process, relatively large loads can be detected, for example pans having a diameter of about 150 mm or more.

  If the result in step S17-4 is No, that is, no load is detected by the detection current Ds1, in step S17-5, the heating coils A1 and A2 detect the on-time Ton2 during the detection period Dp2 Ds2 is supplied.

  In step S17-6, the load detection unit 10 performs the same determination as in step S9-4 of FIG. 9A on the detection values of the input current detector 13 and the output current detector 14 of 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 on 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, the load detection unit 10 determines that the load is placed on the section A in step S17-7. In step S17-8, the load detection unit 10 determines whether the result of the latest placement detection is the same as the result in the immediately preceding detection cycle.

  When the result of step S17-8 is Yes, the load detection unit 10 determines the mounting situation in the section A in step S17-9. 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 that of steps S17-3 to S17-10 of FIG.

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

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

  If the result in step S17-12 is No, that is, no load is detected by the detection current Ds1, in step S17-13, the heating coils B1 and B2 detect the on-time Ton2 during the detection period Dp2 Ds2 is supplied.

  In step S17-14, the load detection unit 10 performs the same determination as step S9-4 in FIG.

  When the result in step S17-14 is No, that is, when the load is not detected even in the detection current Ds2, in step S17-18, the load detection unit 10 determines that the load is not placed on 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, the load detection unit 10 loads the load on the section B in step S17-15. Is determined to be placed. In step S17-16, the load detection unit 10 determines whether the result of the latest placement detection is the same as the result in the immediately preceding detection cycle.

  When the result of step S17-16 is Yes, the load detection unit 10 determines the mounting situation in the section B in step S17-17. 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, when the result of determination of the mounting condition shown in FIG. 17A is "the mounting condition in section A is determined", the process proceeds to step S17-23. . If not, the process proceeds to step S17-20.

  In step S17-20, when the result of determination of the mounting condition shown in FIG. 17A is “load is placed on section A”, the process proceeds to step S17-21. If not, the process proceeds to step S17-23.

  In step S17-21, the detection current Ds3 is sequentially and individually supplied to the heating coils A1 and A2. The load detection unit 10 specifies the position in the section A by determining whether a load is placed above each of the heating coils A1 and A2 of the section A.

  In step S <b> 17-22, the load detection unit 10 tentatively determines the mounting situation which is the result of the position specification in the section A.

  In steps S17-23 to S17-26, the same process as in steps S17-19 to S17-22 is performed on the section A. In this way, the determination of the placement status in the second and subsequent detection cycles is completed. The processes shown in FIGS. 17A to 17C are repeatedly performed after the next detection cycle.

  According to the determination of the placement condition of the present embodiment, the load is placed above the heating coil adjacent to the heating coil on which the load is placed up until the predetermined number of detection cycles elapses. When is detected, the load detection unit 10 determines that it is due to the movement of the load. If 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 another load being placed.

  Thus, the induction heating cooker of the present embodiment can determine the placement state of the load.

  According to the determination of the placement situation of the present embodiment, after the load detection and the temporary determination or decision on the placement situation are performed in section A, the load detection in section B and the temporary decision on the placement situation or A decision is made.

  However, it is not limited to this. For example, after load detection in both of the sections A and B is performed, temporary determination or determination on the mounting status in the sections A and B may be performed.

  After load detection is performed not only in the left heating area Lh but also in all the heating areas H, temporary determination or determination on the mounting situation may be performed.

  According to the determination of the placement situation of the present embodiment, when the load is placed across a plurality of heating regions, the load detection unit 10 can detect the placement situation of the load more accurately. . As a result, the drive control unit 11 can operate the appropriate heating coil corresponding to the mounting situation to inductively heat the load.

Fifth Embodiment
Hereinafter, the induction heating cooker of Embodiment 5 of this indication is demonstrated using FIG. 18A-FIG. 22B.

  The induction heating cooker of the present embodiment has the same configuration as that of the first embodiment shown in FIGS. The induction heating cooker according to the present embodiment includes the placement 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. The placement status determination is sequentially performed.

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

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

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

  In step S19-9 in FIG. 19B, when the result of position specification shown in FIG. 19B is “load is placed above at least one of 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 temporarily determines the mounting situation in the section A.

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

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

  FIG. 20A, FIG. 20B, and FIG. 21 are flowcharts for determination of the mounting situation according to the present embodiment.

  Determination of the mounting situation shown in steps S20-1 to S20-18 in FIG. 20A and FIG. 20B is confirmation of the mounting situation according to the fourth embodiment shown in steps S17-1 to S17-18 in FIG. 17A and FIG. 17B. Is the same as Therefore, the description of FIG. 20A and FIG. 20B is omitted.

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

  In step S21-2, when the result of determination of the mounting condition shown in FIG. 20B is "the mounting condition in section B is determined", the process proceeds to step S21-3. Otherwise, the load detection unit 10 concludes that the placement situation is not determined in the sections A and B, and ends the determination of the placement situation. The process returns to step S19-1 of FIG. 19A to perform positioning again.

  In step S21-3, when the result of the process shown in FIG. 20A is “load is placed on section A”, the process proceeds to step S21-4. Otherwise, the load detection unit 10 concludes that the placement situation is determined in section B and the load is not placed on section A, and ends the determination of the placement situation. The process proceeds to FIG. 22A.

  In step S21-4, the detection current Ds3 is sequentially and individually supplied to the heating coils A1 and A2. The load detection unit 10 determines whether 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 placement situation is determined in section B and the placement situation is temporarily determined in section A, and ends the determination of the placement situation. 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 section B is determined", the load detection unit 10 determines that the placement status in sections A and B is determined. Conclude that the placement situation is finalized. The process proceeds to FIG. 22A. If not, the process proceeds to step S21-7.

  In step S21-7, when the result of determination of the mounting condition shown in FIG. 20B is "load is placed on section B", the process proceeds to step S21-8. Otherwise, the load detection unit 10 concludes that the placement situation is determined in section A and the load is not placed on section B, and terminates the determination of the placement situation. The process proceeds to FIG. 22A.

  In step S21-8, the detection current Ds3 is sequentially and individually supplied to the heating coils B1 and B2. The load detection unit 10 determines whether 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 placement situation is determined in section A and the placement situation is temporarily determined in section B, and ends the determination of the placement situation. The process proceeds to FIG. 22A.

  As described above, in the second detection cycle, after the determination of the placement status shown in FIGS. 20A, 20B, and 21 is performed, in the third and subsequent detection cycles, the detection cycle shown in FIGS. The change is implemented.

  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 placement detection has been performed a predetermined number of times (N times, for example, five times) continuously. The process returns to step S20-1 in FIG. 20A until the number of placement detections is N. If the placement detection is performed N times consecutively, the process proceeds to step S22-2.

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

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

  In step S22-5, the load detection unit 10 performs the same determination as in step S9-4 of FIG. 9A on the detection values of the input current detector 13 and the output current detector 14 of the section A. In this process, a relatively large load, for example a pan with a diameter of about 150 mm or more, is detected.

  If the result in step S22-5 is No, that is, no load is detected by the detection current Ds1, in step S22-6, the heating coils A1 and A2 detect the on-time Ton2 during the detection period Dp2 Ds2 is supplied.

  In step S22-7, the load detection unit 10 performs the same determination as in step S9-4 of FIG. 9A on the detection values of the input current detector 13 and the output current detector 14 of the section A. When the result in step S22-7 is No, in step S22-11, the load detection unit 10 determines that the load is not placed on 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, the load detection unit 10 determines that the load is placed on the section A in step S22-8. In step S22-9, the load detection unit 10 determines whether the result of the latest placement detection is the same as the result in the immediately preceding detection cycle.

  If the result of step S22-9 is Yes, then in step S22-10, the detection cycle for section A is extended from detection cycle T0 to detection cycle T1. In the present 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 steps S22-4 to S22-11 is performed on the section B.

  In step S22-12, the detection current Ds1 is supplied to the heating coils B1 and B2 in the on-time Ton1 during the detection period Dp1.

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

  If the result in step S22-13 is No, that is, no load is detected by the detection current Ds1, in step S22-14, the heating coils B1 and B2 detect the on-time Ton2 during the detection period Dp2 Ds2 is supplied.

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

  When the result in step S22-15 is No, that is, when the load is not detected even in the detection current Ds2, the load detection unit 10 determines that the load is not placed in the section B in step S22-19. . 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, the load detection unit 10 detects the load on the section B in step S22-16. It determines that it has been placed. In step S22-17, the load detection unit 10 determines whether the result of the latest placement detection is the same as the result in the immediately preceding detection cycle.

  If the result of step S22-17 is YES, then in step S22-18, the detection cycle for section B is extended from detection cycle T0 to 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.

  In step S22-20, placement detection is performed. 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 area, for example, the central heating area Ch.

  If the result of step S22-21 is No, placement detection is performed for each determined sensing cycle. When 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 section A, temporary determination or determination is performed on the placement situation in section A. Subsequently, when it is detected that the load is placed in the section B, the placement situation in the section B is tentatively determined or confirmed.

  However, when the load detection in the sections A and B ends, the temporary determination or determination may be performed on the placement situation in the sections A and B.

  When load detection in not only the left heating area Lh but in all the heating areas H is finished, the temporary determination or determination may be performed on the placement situation in all the heating areas H.

  Thereby, when the load is placed across a plurality of sections, the loading situation of the load can be accurately detected.

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

DESCRIPTION OF SYMBOLS 1 case 2 top plate 3, 31, 32, 33, 33, A1, A2, B1, B2 heating coil 4 drive part 5 operation display part 6 infrared sensor 7 thermistor 8 switching part 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 Choke coil 17 Capacitor 18 Filter circuit 19a, 19b Switching element 20 Snubber capacitor 21a, 21b, 21c, 21d Resonant capacitor 22 Input voltage detector 24 Clamp capacitor 50 controller

The inverter 9 is configured by connecting in series a switching element 19a disposed on the high voltage side and a switching element 19b disposed on the low voltage side. For example, IGBTs are used as the switching elements 19a and 19b. Reverse conduction diodes are connected in parallel to switching elements 19a and 19b, respectively. The inverter 9 is connected to both ends of the capacitor 17. Drive control unit 11 controls switching elements 19a and 19b.

If the result is the same as before the detection of the change in the detected value, the load detection unit 10 determines that there is no change in the mounting condition, and the switching unit 8 detects the change in the detected value. In the same state, that is, the heating coil A1 is disconnected from the inverter 9, and the heating coil A2 is returned to the state of connection to the inverter 9. This is because the change in the detected value is likely to be due to a slight movement of the load without the need to change the heating coil 3 to be operated.

Claims (7)

A top plate configured to carry a load;
A plurality of heating coils provided below the top plate,
At least one drive configured to supply high frequency power to the plurality of heating coils;
An electrical signal detection unit configured to detect an electrical signal associated with an element included in the drive unit;
A control unit configured to receive the electrical signal and control the drive unit;
Equipped with
The control unit controls the at least one drive unit to repeatedly supply the plurality of heating coils with the detection current, which is the high frequency power, at a predetermined detection cycle, and responds to the electric signal in response to the detection current. On the basis of which the placement of the load is detected above the plurality of heating coils,
The control unit is configured to temporarily determine the placement condition of the load when the placement of the load is detected above any one of the plurality of heating coils,
The control unit sets a new load above the heating coil adjacent to the heating coil related to the provisionally determined setting situation in the detection cycle after the provisionally determined detection cycle. An induction heating device configured to determine the provisionally determined placement condition if not detected. The control unit is configured to load a new load at the detection cycle after the detection cycle in which the temporary determination is made, above the heating coil adjacent to the heating coil related to the provisionally determined setting situation. When a position is detected, it is determined that the load has moved, and the setting situation in the detection cycle after the detection cycle in which the temporary determination is made is temporarily determined again,
In the detection cycle after the detection cycle in which the control unit is tentatively determined again, a new load is added above the heating coil adjacent to the heating coil related to the temporarily decided status again. The induction heating apparatus according to claim 1, wherein when the placement is not detected, the provisionally determined placement situation is determined again. The control unit is configured to load a new load at the detection cycle after the detection cycle in which the temporary determination is made, above the heating coil adjacent to the heating coil related to the provisionally determined setting situation. When a position is detected, it is determined that another load has been placed, and the placement status of the other load is tentatively determined, and the placement status in the detection cycle in which the tentative determination is made is determined. Configured to
The heating coil adjacent to the heating coil related to the other loading condition at the detection cycle after the detection cycle in which the control condition is temporarily determined for the other loading condition. The induction heating apparatus according to claim 1, wherein the induction heating apparatus is configured to determine the provisionally determined placement condition if the placement of a new load is not detected above. The top plate has at least one heating area;
The at least one heating zone comprises a plurality of compartments;
The induction heating apparatus according to claim 1, wherein the plurality of heating coils and the at least one drive unit are provided for one of the plurality of sections. 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;
Detecting the placement of the load above the plurality of heating coils based on the electrical signal responsive to the sensed current;
Temporarily determining the placement status of the load when the placement of the load is detected above any one of the plurality of heating coils;
In the case where the placement of the load is not detected above the heating coil adjacent to the heating coil associated with the provisionally determined setting situation in at least one detection cycle following the detection cycle in which the provisional determination is made, And a step of determining the temporarily determined placement situation. When a new load is detected in the detection cycle after the detection cycle in which the temporary decision has been made, above the heating coil adjacent to the heating coil related to the tentatively determined placement situation Determining again that the load has moved, and temporarily determining a setting situation in the detection cycle after the detection cycle in which the temporary determination has been made;
In the detection cycle after the detection cycle in which the provisional determination is performed again, the placement of a new load is not detected above the heating coil adjacent to the heating coil related to the previously described provisional placement situation. 6. The method of detecting a load in an induction heating apparatus according to claim 5, further comprising the step of, in the case, determining the pre-decided setting situation again. When a new load is detected in the detection cycle after the detection cycle in which the temporary decision has been made, above the heating coil adjacent to the heating coil related to the tentatively determined placement situation Determining that the other load has been placed, and temporarily determining the placement status of the other load, and determining the placement status in the detection cycle in which the temporary determination has been made;
At a detection cycle after the detection cycle in which the setting state of the other load is tentatively determined, a new one above the heating coil adjacent to the heating coil related to the setting situation of the other load The method for detecting a load in an induction heating apparatus according to claim 5, further comprising the step of determining the provisionally determined placement condition if the placement of the load is not detected.

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