JP2017022144A - Induction heating cooker and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating cooker capable of driving both an induction heating coil and a current supply coil according to a simple and inexpensive method by adjusting a drive frequency of a high frequency current supplied from a single inverter circuit.SOLUTION: The induction heating cooker comprises: a heating cabinet including a heat insulation substrate with which a plurality of recesses are provided insides as a rear wall; a plurality of heaters disposed in the plurality of recesses in a removable manner and each consisting of an electrically closed conductor; a current supply coil for performing resistance heating on the plurality of heaters by forming a high frequency magnetic flux which interlinks with the plurality of heaters, and supplying a high frequency current to the plurality of heaters; an U-shaped magnetic body disposed to enclose at least a part of the current supply coil and to cover the recesses of the heat insulation substrate; and an inverter circuit which supplies the high frequency current to an induction heating coil and the current supply coil. The current supply coil and the induction heating coil are connected in parallel with each other.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an electromagnetic induction heating cooker having a plurality of heating units and a control method thereof. In particular, the present invention provides an induction heating coil that induction-heats an object to be heated such as a pan when a high-frequency current is supplied, and a high-frequency magnetic flux that is linked to the heater, thereby supplying the heater with the high-frequency current. The present invention relates to an induction heating cooker having a current supply coil for resistance-heating a heater and a control method thereof.

  Many electromagnetic induction heating cookers having a plurality of heating units have been proposed so far. For example, in the electromagnetic induction heating cooker described in Patent Document 1, a high-output heating unit is produced at low cost, and the entire device is In order to realize a high thermal power burner without increasing power consumption, each heating unit has an independent high-frequency generator and a corresponding heating coil, and the first heating unit includes a plurality of heating coils. The one heating coil of the plurality of heating coils provided in the first heating unit is configured to supply a high frequency current from the high frequency generator of the second heating unit when necessary.

  Specifically, the electromagnetic induction heating cooker described in Patent Document 1 has two induction heating sections, and one induction heating section is provided with an auxiliary coil for high heating power, It is connected to the second high frequency generator via a relay. That is, according to the electromagnetic induction heating cooker described in Patent Document 1, when high-heat cooking is performed in the first induction heating unit, the relay of the second high-frequency generator is switched to the auxiliary coil side, Large heating power can be obtained by supplying a high-frequency current to the auxiliary coil from the high-frequency generator and heating the pan together with the first induction heating unit. (FIG. 3 of Patent Document 1)

  Further, the induction heating cooker described in Patent Document 2 has two heating coils connected in parallel to each other and having different resonance frequencies, and the load to be heated can be selected by changing the driving frequency. It is configured.

  Specifically, in the induction heating cooker described in Patent Document 2, when it is desired to set the heating power of two heating coils to 1000 W and 600 W, for example, the resonance frequency of the load circuit including each heating coil is set to 25 kHz and 28 kHz, for example. In order to realize the above heating power of each heating coil, the drive frequency is set to 26 kHz, the pair of transistors are alternately turned on and off, and the voltage of the DC power supply is adjusted to 85 V. (FIG. 4 of Patent Document 2).

  Further, Patent Document 3 is a heating cooker generally used as a grill cooker, and includes a single coil unit and a heater made of an electrically closed conductor that is detachably disposed inside the heating chamber. , A current supply coil arranged outside the heating chamber, an inverter circuit for supplying high-frequency current to the current supply coil, and a magnetic body arranged so that high-frequency magnetic flux generated from the current supply coil of the coil unit is linked to the heater A cooking device equipped with the above has been proposed.

JP-A-5-347180 (FIG. 3) Japanese Patent No. 2722738 (FIG. 4) JP 2011-187405 A

  However, according to the electromagnetic induction heating cooker described in Patent Document 1, it is necessary to switch the relay of the second high-frequency generator to the auxiliary coil side in order to perform high heating power cooking with the first induction heating unit. At this time, the second induction heating unit is disconnected from the second high frequency generator and loses the power supply means, and therefore cannot be used simultaneously with the first induction heating unit.

  In addition, in the induction heating cooker described in Patent Document 2, the resonance frequency of a load circuit including two heating coils is designed to be constant, but when induction heating a heated object such as a pan, the size of the pan and Depending on the material and the like, the resonance frequency of the load circuit changes, that is, the frequency-heating power relationship shown in FIG. 4 varies. Therefore, even if the induction heating cooker described in Patent Document 2 adjusts the driving frequency and the output voltage of the DC power supply, the resonance frequency of the load circuit changes depending on the size and material of the pan, etc. The heating power of the heating coil cannot be precisely controlled.

  Furthermore, the induction heating cooker described in Patent Document 2 needs to adjust the switching phase of a pair of thyristors provided in the DC power supply in order to control the output voltage of the DC power supply, and the circuit configuration is complicated and expensive. Inevitable.

  Moreover, when employ | adopting the heating cooker (grill cooker) of patent document 3 for the induction heating cooking appliance which has a general 2 or 3 IH heating part, the induction heating coil of each IH heating part, There is a problem that an independent inverter circuit for supplying a high-frequency current to the current supply coil of the grill cooker is required, which increases the number of parts and increases the manufacturing cost. In particular, when the induction heating cooker has a grill heating unit for cooking fish or the like in addition to the IH heating unit, it is necessary to separately provide a power supply circuit unit for supplying power to the grill heating unit, resulting in an increase in the number of parts. A means to solve the problem of improvement is strongly desired.

  Therefore, the present invention provides a high frequency that is supplied from a single inverter circuit according to the induction heating coil and the current supply coil selected by the user when the high frequency current is supplied to the induction heating coil and the current supply coil that are connected in parallel to each other. An object of the present invention is to provide an induction heating cooker that can drive one or both of the induction heating coil and the current supply coil by a simple and inexpensive method by adjusting the drive frequency of the current.

  The present invention has been made to solve the above-described problems, and relates to an induction heating cooker, which is placed on a top plate when a top plate on which a heated object is placed and a high-frequency current is supplied. An induction heating coil for inductively heating the object to be heated; a heating chamber provided below the top plate, the heating chamber having a heat insulating substrate provided with a plurality of recesses on the inside as a rear wall; and the heat insulation A plurality of heaters that are detachably disposed in the plurality of recesses provided on the substrate and made of an electrically closed conductor, and form a high-frequency magnetic flux interlinking with the plurality of heaters when a high-frequency current is supplied. Then, by supplying a high-frequency current to the plurality of heaters, a current supply coil that resistance-heats the plurality of heaters, and at least a part of the current supply coil are surrounded, A U-shaped or U-shaped magnetic body disposed so as to cover a portion, and an inverter circuit that supplies a high-frequency current to the induction heating coil and the current supply coil, the current supply coil and the induction The heating coils are connected in parallel to each other.

  According to the present invention, by adjusting the driving frequency of the high-frequency current supplied from a single inverter circuit, one or both of the induction heating coil and the current supply coil can be driven in a simple and inexpensive manner. A cooker can be provided.

1 is a perspective view schematically illustrating the entire induction heating cooker 1 according to the present invention. It is sectional drawing of the induction heating coil when cut | disconnecting by XY plane of FIG. It is sectional drawing of the center IH heating part when cut | disconnecting by the YZ plane of FIG. It is sectional drawing of a grill heating part when cut | disconnecting by the YZ plane of FIG. It is a perspective view of a coil unit when a rear wall is omitted. 1 is a schematic circuit block diagram of a power supply circuit unit according to a first embodiment of the present invention. FIG. 7 is a detailed circuit block diagram of the power supply circuit unit of FIG. 6. It is the graph which plotted the magnitude | size of the high frequency current I when the high frequency current which has various drive frequencies was supplied to the to-be-heated body which has a resonance frequency. It is a timing chart of the control signal which controls the switching element of an inverter circuit part with a drive frequency. It is a graph which shows the relationship between a drive frequency and the heating electric power of the center IH heating part in a no-load state, and a grill heating part. It is a graph which shows the relationship between a drive frequency and the heating electric power of the center IH heating part in a state where the load was added, and a grill heating part. Relationship between driving frequency and heating power when the pan is made of ferromagnetic, magnetic, and non-magnetic materials, and only when the lower heater only, upper heater only, or both heaters are installed It is the same graph as FIG. 11 which shows the relationship between a drive frequency and heating power. It is a graph which shows the relationship between the drive frequency of a high frequency current, and the heating power of a center IH heating part and a grill heating part. FIG. 2 is an enlarged plan view of an operation unit and a display unit shown in FIG. 1. FIG. 2 is an enlarged plan view of an operation unit and a display unit shown in FIG. 1. It is a flowchart which shows the control method of the induction heating cooking appliance when a user selects center IH cooking. It is a flowchart which shows the control method of the induction heating cooking appliance when a user selects grill cooking. It is a flowchart which shows the control method of the induction heating cooking appliance in the case of wanting grill cooking during central IH cooking. It is a flowchart which shows the control method of the induction heating cooking appliance in the case of wanting central IH cooking during grill cooking. (A) is a wave form diagram which shows the control signal supplied to the switching element of the inverter circuit part during grill cooking, (b) shows the control signal supplied to the switching element of the inverter circuit part during central IH cooking (C) is a timing chart showing a period during which high-frequency currents having different frequencies are supplied when the central IH heating unit and the grill heating unit are heated simultaneously. It is a flowchart which shows the control method of the induction heating cooking appliance in the case of performing central IH cooking and grill cooking simultaneously. It is a timing chart which shows the period when the high frequency current which has a different drive frequency is supplied to a central IH heating part and a grill heating part when entering into a simultaneous heating mode from the state where the central IH heating part is used.

  Embodiments of an induction heating cooker according to the present invention will be described below with reference to the accompanying drawings. In the description of each embodiment, terms indicating directions (for example, “up / down / left / right” and “XYZ direction”) are used as appropriate for easy understanding. The terms are not intended to limit the invention. In the accompanying drawings, the same components are referred to by the same reference numerals.

Embodiment 1 FIG.
The first embodiment of the induction heating cooker according to the present invention will be described in detail below with reference to FIGS. FIG. 1 is a perspective view schematically illustrating the entire induction heating cooker 1 according to the present invention. An induction heating cooker 1 shown in FIG. 1 is arranged roughly on the left and right, with a casing 2 mainly composed of sheet metal, a top plate 3 formed of glass or the like covering almost the entire upper surface thereof, and the like. A pair of left IH heating unit 4a and right IH heating unit 4b, and a central IH heating unit 10 disposed in the center of the top plate 3 (in this specification, these are collectively referred to as “IH heating units 4a, 4b, 10 And a grill heating unit 20.

  The induction heating cooker 1 includes an operation unit (operation panel) 30 used by a user to operate each of the IH heating units 4a, 4b, and 10 and the grill heating unit 20, and each of the IH heating units 4a, 4b, and 10 Control state (user setting values of thermal power and cooking time, etc.) and operation of the thermal power adjustment dials 31a, 31b, 32 for adjusting the “thermal power (heating power)”, the IH heating units 4a, 4b, 10 and the grill heating unit 20 An LCD display (liquid crystal display) 34 for displaying guides and the like, and an LED display (LED level) for displaying the heating power set by the user for each IH heating unit 4a, 4b, 10 and grill heating unit 20 Meter) 36. FIG. 1 shows an example of the number, arrangement, and configuration of the operation unit and the display unit, and the present invention is not limited to these.

  The induction heating cooker 1 has an exhaust port 5 a and an intake port 5 b provided on the rear surface side on the top plate 3. Further, as will be described later, the induction heating cooker 1 is provided with a power supply circuit unit 50 for supplying a high-frequency current to each IH heating unit 4a, 4b, 10 and grill heating unit 20 for each heating unit. . FIG. 1 shows an example of the number, size, arrangement position, and the like of the exhaust port 5a and the intake port 5b, and the present invention is not limited to these.

  The left side IH heating unit 4a, the right side IH heating unit 4b, and the central IH heating unit 10 are spirally wound around a conductive wire (such as a litz wire) made of any metal with an insulating coating below the top plate 3, for example. (In parallel to the XY plane) and having an induction heating coil 12 constructed by winding. Although the diameter and the maximum heating power of the induction heating coil 12 of each IH heating unit 4a, 4b, 10 are different, the basic structure may be the same. FIG. 1 shows an example of the size and arrangement of the left side IH heating unit 4a, the right side IH heating unit 4b, and the central IH heating unit 10, and the present invention is not limited to these.

In general, the left side IH heating unit 4a and the right side IH heating unit 4b are used for cooking that requires a large heating power, such as stir-fried food and boiled food, and cooking such as fried food that requires temperature control. On the other hand, the central IH heating unit 10 is used for cooking that requires a relatively small heating power, such as stewed dishes and warm dishes, and is used less frequently than the left IH heating unit 4a and the right IH heating unit 4b. . In addition, the grill heating unit 20 is often used for grilled dishes such as grilled fish, and similarly, the grill heating unit 20 is less frequently used than the left IH heating unit 4a and the right IH heating unit 4b. Therefore, the possibility of performing stewed food and grilled food at the same time is even smaller, and a separate power circuit section (inverter circuit section 70, FIG. 6) for supplying power to each of the central IH heating section 10 and the grill heating section 20 is provided. Increases the number of parts and increases the cost. Therefore, the present invention intends to provide a cheaper induction heating cooker 1 by sharing a part of the power supply circuit unit 50 of the central IH heating unit 10 and the grill heating unit 20 as described below. is there.
However, the present invention is not limited to the case where the central IH heating unit 10 and the grill heating unit 20 share a part of the single power supply circuit unit 50, but the left IH heating unit 4 a or the right IH heating unit 4 b and the grill heating unit 20. Needless to say, the present invention can be similarly applied to a case where a part of a single power supply circuit unit 50 is shared.

Here, the central IH heating unit 10, the grill heating unit 20, and the power supply circuit unit 50 that constitute the induction heating cooker 1 according to the first embodiment of the present invention will be described in detail below.
2 is a cross-sectional view of the induction heating coil 12 when cut along a plane parallel to the XY plane of FIG. 1, and FIG. 3 is a cross-sectional view of the central IH heating unit 10 when cut along a plane parallel to the YZ plane of FIG. It is sectional drawing. The induction heating coil 12 shown in FIG. 2 can adopt any shape and the number of turns of the coated conductor as long as a desired heating power can be obtained. It may be a single coil formed by concentrically winding a litz wire made into a stranded wire, or may have an inner coil 12a and an outer coil 12b that are divided in the radial direction. . 3 includes an induction heating coil 12, a coil base 13 that supports the induction heating coil 12, and a plurality of rod-like magnetic bodies (ferrite cores) 14 that extend radially in the radial direction. Furthermore, unnecessary high-frequency magnetic flux that does not interlink (contribute) to the heating of the pan K placed on the induction heating coil 12 via the top plate 3 is provided around the coil base 13 that supports the induction heating coil 12. In order to prevent leakage to the outside of the induction heating cooker 1, a metallic ring (cancelling ring) 100 made of aluminum or the like is preferably attached. The induction heating coil 12 is connected to the power supply circuit unit 50 (inverter circuit unit 70) as described above, and is configured such that a high-frequency current is supplied from the power supply circuit unit 50.
In addition, the litz wire and the number of turns constituting the induction heating coil 12 are set to the resonance frequency Fr and the load resistance R of the resonance circuit 76a including the induction heating coil 12, the resonance capacitor 75a, and the pan K that is the object to be heated. It has an influence.

  FIG. 4 is a cross-sectional view of the grill heating section 20 when cut along a plane parallel to the YZ plane of FIG. The grill heating unit 20 is guided to a box-shaped heating chamber 21 built in the housing 2, an upper heater 22a and a lower heater 22b disposed in the heating chamber 21, and an upper heater 22a and a lower heater 22b. And a coil unit 15 through which a current flows.

  The heating chamber 21 includes an upper wall 23a, a lower wall 23b, an openable / closable front door 23c, a rear wall 23d, and a pair of side walls (not shown), and is configured as a rectangular parallelepiped box-shaped container. Since the inside of the heating chamber 21 becomes hot during cooking, the upper wall 23a, the lower wall 23b, and the side wall are, for example, iron plates (including steel plates such as galvanized steel plates and carbon steel plates), magnetic or nonmagnetic It is preferable to form a heat insulating wall in which two metal plates such as a stainless steel plate are stacked and an air layer is sandwiched therebetween. In order to further improve the heat insulation of the upper wall 23a, the lower wall 23b, and the side wall, instead of providing an air layer, a heat insulating material may be disposed between two metal plates, or a part of a single layer iron plate Or you may provide a heat insulating material in all. However, it is preferable that the front door 23c improve heat insulation using a translucent member such as heat-resistant glass so that the user can see the state of the food being cooked. Further, the rear wall 23d constitutes a heat insulating substrate 17 made of a heat insulating material and has a recess 24.

  The front door 23c is fixed to a slide rail 26 that can move back and forth with respect to the heating chamber 21 (in the left-right direction in FIG. 4), and a tray 27 and a grille 28 are also fixed to the slide rail 26. It is attached to slide along with the door 23c. Accordingly, when the front door 23c is opened, the tray 27 and the grill 28 are moved to the front of the heating chamber 21 in accordance with the movement of the slide rail 26, so that foods placed on the grill 28 can be taken in and out.

  FIG. 5 is a perspective view of the coil unit 15 when the rear wall 23d is omitted. The coil unit 15 surrounds at least a part of a planar coil (current supply coil) 16 spirally wound on a plane parallel to the rear wall 23d of the heating chamber 21, and the planar coil 16, and a heat insulating substrate. And U-shaped or U-shaped magnetic bodies 18a and 18b having openings covering the 17 concave portions 24. The planar coil 16 of the coil unit 15 is formed by winding a conductor such as a litz wire a plurality of times. For example, a so-called litz wire formed by twisting 90 coated conductors having a diameter of 0.2 mm is wound 16 times in a planar shape. It may be formed so that its outer shape is substantially rectangular or substantially elliptical. The litz wire and the number of turns constituting the planar coil 16 affect the resonance frequency Fr and the load resistance R of the resonance circuit 76b including the planar coil 16, the resonance capacitor 75b, and the heater 22, which will be described later.

  The upper heater 22a and the lower heater 22b are (hollow) metal pipes or (solid) metal bars made of electrically closed (looped or endless) conductors, as shown in FIG. In addition, a part thereof is configured to be detachably accommodated in the recess 24 of the heat insulating substrate 17.

  The planar coil 16 is sandwiched between the magnetic bodies 18 a and 18 b and the heat insulating substrate 17. Since a part of the planar coil 16 is oriented in the same direction, when a high-frequency current is supplied from the power supply circuit unit 50 (inverter circuit unit 70), the heaters 22a, High-frequency magnetic flux in the same direction is formed around the magnetic bodies 18a and 18b including a part of 22b. Since the high frequency magnetic flux generated around the heaters 22a and 22b is linked to the heaters 22a and 22b, an induction current is generated in the heaters 22a and 22b made of a conductive material having an electrically closed shape. Heated heaters 22a and 22b can heat the inside (and food) of the heating chamber 21. Accordingly, when a high frequency current is supplied to the planar coil 16 of the coil unit 15, a high frequency magnetic flux interlinking with the heaters 22a and 22b is formed, and a substantial large current (high frequency current) is applied to the heaters 22a and 22b. In terms of what is supplied, it can also be called a “current supply coil” for the heaters 22a and 22b. Thus, the heaters 22a and 22b can efficiently cook the food in the heating chamber 21, and can be easily removed from the heating chamber 21 and cleaned with running water after cooking.

  In addition, the coil unit 15 has an aluminum cover (which covers the magnetic bodies 18a and 18b) in order to reduce power loss caused by leakage of high-frequency magnetic flux generated by the planar coil 16 to the heating chamber 21 or other metal components. (Cancel cover) 19a (FIG. 4). The aluminum cover 19a is provided with an air cooling fan 19b facing the planar coil 16 and the magnetic bodies 18a, 18b (FIG. 4), and a wind tunnel for controlling cooling air for efficiently cooling the planar coil 16 and the magnetic bodies 18a, 18b. Also works.

Next, the power supply circuit unit 50 according to the first embodiment of the present invention will be described in detail. The power supply circuit unit 50 according to the first embodiment of the present invention supplies high-frequency currents independently to the induction heating coils 12 of the IH heating units 4a, 4b, and 10 as described above, and the current of the coil unit 15 as well. A high-frequency current is also supplied to the supply coil 16, and in particular, an inverter circuit unit 70 that supplies a high-frequency current to the central IH heating unit 10 and the grill heating unit 20 is shared.
Note that the power supply circuit unit that supplies the high-frequency current to the left IH heating unit 4a and the right IH heating unit 4b is omitted in order to avoid complicated description of the present invention.

  FIG. 6 is a circuit block diagram showing a schematic circuit configuration of the power supply circuit unit 50 according to the first embodiment of the present invention, and FIG. 7 is a detailed circuit block diagram of the power supply circuit unit 50. The power supply circuit unit 50 according to the first embodiment generally includes a converter (for example, a diode bridge) 51 that converts a commercial power supply AC into a direct current, and a filter circuit 52 (smoothing capacitor 52b and choke coil) connected to the output terminal of the converter 51. 52a), a pair of switching elements 71a and 71b such as an inverter circuit unit 70 (IGBT element (insulated gate bipolar transistor element)), FWD elements 72a and 72b connected in parallel thereto, and snubber capacitors 73a and 73b. And a half-bridge circuit. The power supply circuit unit 50 includes a protective component 77 (for example, a fuse) for protecting from a failure due to an overcurrent or the like.

The first resonance capacitor 75a for the central IH heating unit 10 and the induction heating coil 12 are connected in series to the output end 74 of the half bridge circuit, and similarly, the second resonance capacitor 75b for the coil unit 15 is used. And the current supply coil 16 are connected in series, and the induction heating coil 12 and the current supply coil 16 are connected in parallel. 6, the first and second resonant capacitors 75a, 75b is represented by Cc and Cg, the induction heating coil 12 is represented by an inductance _{L C} and the load resistance _{R C,} the current supply coil 16 is an inductance Lg and load It is represented by resistance Rg. That is, in FIG. 7, the first resonance capacitor 75a (Cc) and the induction heating coil 12 (L _C , R _C ) constitute a first resonance circuit 76a, and the second resonance capacitor 75b (Cg) and the current supply coil 16 (Lg, Rg) constitutes the second resonance circuit 76b. The inverter circuit unit 70 is not limited to a half-bridge circuit, and may be configured using a full-bridge circuit, and the present invention is not limited to the circuit configuration of the inverter circuit.

  The induction heating coil 12 forms an eddy current in the metal part on the bottom surface of the pan K by the high-frequency magnetic flux formed in the radial direction interlinking with a heated body K such as a pan placed on the top plate 3. The pot K is directly heated by Joule heat generated by eddy current. On the other hand, as described above, the current supply coil 16 generates an electromotive force in the heaters 22a and 22b for canceling the high-frequency magnetic flux formed around the loop heaters 22a and 22b including the magnetic bodies 18a and 18b. The heaters 22a and 22b are heated by the Joule heat generated by the induced current, and the inside (and food) of the heating chamber 21 is heated. That is, the induction heating coil 12 and the current supply coil 16 are common in that they are coils, but the heating principle and heating mode of the heated body (pan K or heaters 22a and 22b) are different from each other.

  Referring to FIG. 7, the power supply circuit unit 50 according to the first embodiment of the present invention includes, for example, a first load detection means 78a for detecting a power supply current and a power supply voltage flowing at both ends of a commercial power supply, and / or in parallel with each other. There is a second load detecting means 78b for detecting the drive current flowing in the connected first and second resonance circuits 76a and 76b and the drive voltage applied to both ends thereof. In addition, the power supply circuit unit 50 of the first embodiment uses induction heating from the power supply current and power supply voltage obtained by the first load detection means 78a or the drive current and drive voltage obtained by the second load detection means 78b. A load detection unit 80 that detects a resonance frequency Fr (or inductance L) and a load resistance R of a resonance circuit including the coil 12 and the current supply coil 16 is provided. The load detection unit 80 may include a primary component extraction unit described in, for example, the pamphlet of International Patent Application Publication No. WO 2010/137498, and detects the load resistance R (or inductance L) and the resonance frequency Fr. Any load detection unit widely known to those skilled in the art may be used. Since the load detection unit 80 is also described in the above-mentioned International Patent Application Publication Pamphlet, it will not be described in detail. However, if the resonance frequency Fr (or inductance L) and the load resistance R are detected, the loading area of the pan K ( It is possible to know the number of the heaters 22a and 22b (including the presence or absence of the heater) and the material of the pot K or the heaters 22a and 22b. Hereinafter, in the present specification and the like, detecting the resonance frequency Fr (or inductance L) and the load resistance R using the load detection unit 80 is simply referred to as “load detection”.

Furthermore, the induction heating cooker 1 according to the first embodiment includes the above-described operation unit (operation panel) 30, display units 34 and 36 (LCD display unit 34 and LED display unit 36), load detection unit 80, and inverter circuit unit 70. The control circuit unit 90 is connected. The control circuit unit 90 determines whether the user has selected the central IH heating unit 10 or the grill heating unit 20 using the operation unit 30, and the heating to be output by the central IH heating unit 10 or the grill heating unit 20. The inverter circuit unit 70 depends on the power P, the mounting area of the pan K (including the presence or absence of the pan K) or the number of heaters 22a and 22b (including the presence or absence of the heater), and the material of the pan K or the heaters 22a and 22b. switching element 71a, the driving frequency _{F D} and the oN period (period switching elements 71a, 71b to the control signals Sa, Sb are driven by being applied) of 71b to supply the control signal (gate signal) / oFF period (switching It is possible to control the ratio of the control signals Sa and Sb being applied to the elements 71a and 71b.

FIG. 8 is a graph plotting the magnitude of the high-frequency current I when high-frequency currents having various driving frequencies are supplied to the heated object having the resonance frequency Fr. As apparent from FIG. 8, the high-frequency current I is a function of the driving frequency F _D, increases or decreases the resonance frequency Fr as a peak. That high-frequency current I is closer to the resonance frequency Fr, exponentially increases, the switching element 71a of the inverter circuit section 70, also the drive current I flowing to 71b, the driving frequency F _D increases closer to the resonance frequency Fr . However the drive current I, the switching elements 71a, exceeds the maximum allowable drive current _{I MAX} of 71b, the switching element 71a, there is a possibility that 71b is destroyed, the driving frequency _{F D} high frequencies _{(F D} than the resonant frequency Fr It is desirable to select> Fr).

Figure 9 is a timing chart of the control signals Sa, Sb for controlling the switching elements 71a of the inverter circuit section 70, and 71b at the drive frequency _{F D.} At this time, in order to prevent the high-frequency current from flowing directly from the high-voltage side switching element 71a to the low-voltage side switching element 71b without passing through the induction heating coil 12 and the current supply coil 16, the high-voltage side switching element 71a A dead time t _d (drive suspension period) is set between the timing at which the on / off control signals Sa and Sb are supplied and the timing at which the off / on control signals Sa and Sb are supplied to the low-voltage side switching element 71b. It is controlled to provide.

Figure 10 is a graph showing the driving frequency F _D, the relationship between the heating power of the central IH heating unit 10 and the grill heating unit 20 in the no-load state (power value proportional to the square of the high-frequency current I P) . That is, the first resonance circuit 76a including the induction heating coil 12 of the central IH heating unit 10 has at least the first offset frequency ΔFrc higher than the resonance frequency Fr ₀ c when in the no-load state, and about 50 kHz to about 50 kHz. a high-frequency current is supplied with a driving frequency _{F D1} which varies between 80 kHz. Similarly, the second resonance circuit 76b including the current supply coil 16 of the grill heating unit 20 includes at least a second offset frequency ΔFrg higher than the resonance frequency Fr ₀ g when in the no-load state, and about 20 kHz to a high-frequency current is supplied with a driving frequency _{F D2} that vary from about 40 kHz. Here, supplied to the central IH heating unit 10 and the grill heating unit 20, respective resonant frequencies _{Fr 0} c, _Fr 0 g of at least first and second offset frequency DerutaFrc, a high-frequency current having a ΔFrg only large driving frequency _{F D} for, when the driving frequency F _D coincides with the resonant frequency Fr, the switching element 71a, an excessive current flows to 71b, in order to avoid the risk of switching elements 71a, 71b is broken. The first and second offset frequencies ΔFrc and ΔFrg may be, for example, about 1 kHz to about 4 kHz. The difference between the resonance frequencies Fr ₀ c and Fr ₀ g in the no-load state is preferably set to 20 kHz or more in the audible region.

FIG. 11 shows the driving frequency F _D and the heating power P of the central IH heating unit 10 and the grill heating unit 20 when a load is applied (when the pan K is placed and the heaters 22a and 22b are inserted). ₁ is a graph showing the relationship between _{P 2.} When only the central IH heating unit 10 is driven, when the load detection unit 80 detects the resonance frequency Fr ₀ c ′ by load detection, the central IH heating unit 10 has at least a first offset from the resonance frequency Fr ₀ c ′. larger by frequency DerutaFrc, and high-frequency current is supplied with a driving frequency _{F D1} to vary from about 50kHz~ about 80 kHz (solid line on the right). Similarly, when only the grill heating unit 20 is driven, when the load detection unit 80 detects the resonance frequency Fr ₀ g ′ by load detection, the grill heating unit 20 has at least a second frequency greater than the resonance frequency Fr ₀ g ′. large offset frequencies DerutaFrg, and high-frequency current is supplied with a driving frequency _{F D2} to vary from about 20kHz~ about 40 kHz (solid line on the left). Also shows the relationship between the central IH heating unit 10 and the grill heating unit 20 heating power P _1, P ₂ and the driving frequency F _D when the unloaded state of FIG. 10 by dashed lines.

FIG. 12 more specifically shows a case where only the central IH heating unit 10 is driven, and the driving frequency F _D1 when the pan K is made of a ferromagnetic material, a magnetic material, and a non-magnetic material. relationship between the heating power P ₁ (solid line on the right side), and a case of driving only the grill heating unit 20, only the lower heater 22b, only the upper heater 22a, and both heaters 22a, 22b are mounted If a graph showing the relationship between the driving frequency F _D2 and the heating power P ₂ of. For example, when heating the pan K made of a magnetic material using only the central IH heating unit 10, the load detection unit 80 detects the resonance frequency Fr ₀ c ′ by load detection (center solid line in the right graph), and the central IH heating unit the 10 high-frequency current is supplied with a driving frequency _{F D} that varies in the range of the resonance frequency Fr ₀ c 'than by at least a first offset frequency ΔFrc large and about 50kHz~ about 80 kHz. Similarly, for example, when only the upper heater 22a is heated using only the grill heating unit 20, the load detection unit 80 detects the resonance frequency Fr ₀ g ′ by load detection, and the grill heating unit 20 includes the resonance frequency Fr. ₀ g 'than by at least a second offset frequency ΔFrg large and high-frequency current is supplied with a driving frequency _{F D2} to vary from about 20kHz~ about 40 kHz (middle solid line on the left graph).
The relationship between the resonance frequencies Fr ₀ g ′ of the upper heater 22a and the lower heater 22b may be opposite to or the same as the relationship shown in FIG.

In Figure 13, induction heating cooker 1 of the first embodiment, the driving frequency F _D of the high-frequency current I, an example of the relationship between the heating power P _1, P ₂ of the central IH heating unit 10 and the grill heating portion 20 This is a plotted graph. As apparent from FIG. 13, the heating power _{P 1} of the central IH heating unit 10, to the extent the driving frequency _{F D} of about 50kHz~ about 80 kHz, as the driving frequency _{F D} increases, while reducing somewhat slower monotonously , heating power _{P 2} of grill heating unit 20, to the extent the driving frequency _{F D} of about 20kHz~ about 30 kHz, as the driving frequency _{F D} increases, decreases rapidly. Indeed, the central IH heating unit 10, when the driving frequency _{F D} is about 30kHz or less can not be obtained almost heating power _{P 1,} to the contrary, the grill heating unit 20, the driving frequency _{F D} of about 50kHz or higher sometimes, no any heating power P _2.

As described above, the induction heating coil 12 of the central IH heating unit 10 and the current supply coil 16 of the grill heating unit 20 according to the present invention are connected in parallel to the output terminal of the inverter circuit unit 70. Since the bands of the drive frequencies F _D1 and F _D2 (the range of about 50 kHz to about 80 kHz and the range of about 20 kHz to about 40 kHz) do not overlap and are configured to be completely separated, a single inverter circuit 70, either the central IH heating unit 10 or the grill heating unit 20 can be selectively driven.

  Next, the control method according to the first embodiment of the present invention will be described. 14 and 15 are enlarged plan views of the operation unit (operation panel) 30 and the display unit (LCD display unit 34, LED display unit 36) shown in FIG. FIG. 16 is a flowchart showing a control method of induction heating cooker 1 when the user selects central IH cooking in a state where both central IH heating unit 10 and grill heating unit 20 are not used.

In step ST01, when the user wants to heat the pan K on the top plate 3 to cook the food in the pan K (hereinafter referred to as “induction heating mode” in this specification), the operation unit 30 in FIG. When the center IH switch (OFF / ON) 37a is pressed to select center IH cooking, in step ST02, the liquid crystal display unit 34 displays “center IH can be used” in the “center IH menu”, and the center Display that IH cooking is possible. In step ST03, the user selects the heating power P ₁ (for example, “thermal power 2”) of the central IH heating unit 10 using the arrow switches 37b and 37c of FIG. At this time, the control circuit section 90, the driving frequency _{F D} is consistent with the resonance frequency Fr, the switching element 71a, in order to avoid flowing excessive current to 71b, the driving frequency in the range of about 50kHz~ about 80 kHz _{F D1} Among them, for example, control signals Sa and Sb having a maximum drive frequency of 80 kHz are supplied to the inverter circuit unit 70, and in step ST04, the load detection unit 80 detects the resonance frequency Fr ₀ c and the load resistance R (load detection). .

In step ST05, the control circuit unit 90 has a drive frequency F _D (F _D ≧ Fr ₀ c + ΔFrc) that is higher than the resonance frequency Fr ₀ c by at least the first offset frequency ΔFrc, for example, based on the graph of FIG. arrow switch 37b, heating power _{P 1} selected by 37c determines the driving frequency _{F D1} obtained. For example, when the user selects the heating power P ₁ of the central IH cooking, for example, “heating power 4” = 1000 W, by the operation unit 30, in step ST 05, the control circuit unit 90 reduces the driving frequency F _D1 from the graph of FIG. Set to 56 kHz. In step ST06, the control signal Sa having a drive frequency _{F D1} of approximately 56 kHz, is supplied to Sb in the inverter circuit unit 70, the heating power _{P 1} of the central IH heating unit 10 is controlled to 1000W, whereas, in the vicinity of 56 kHz heating power P ₂ from the grill heating unit 20 is substantially zero as described above.
The load detection unit 80 initially supplies the control signals Sa and Sb having the maximum drive frequency of 80 kHz to the inverter circuit unit 70 to perform load detection, and obtains the resonance frequency Fr ₀ c. The resonance frequency Fr ₀ c from performs load detection iteratively by using the offset frequency ΔFrc only large driving frequency F _D1, seeking higher precision resonance frequency Fr 1 _c, the user so as to more accurately achieve the heating power P ₁ to the desired May be.

  FIG. 17 is a flowchart showing a control method of induction heating cooker 1 when the user selects grill cooking in a state where both central IH heating unit 10 and grill heating unit 20 are not used.

In step ST11, when the user wants to cook the food in the heating chamber 21 by resistance heating the heaters 22a and 22b of the grill heating unit 20 (hereinafter referred to as “resistance heating mode” in this specification), FIG. In step ST12, the liquid crystal display unit 34 displays a “grill cooking menu” to indicate that grill cooking is possible. In step ST13, the user presses the menu switch 38b in FIG. 15 to select “fillet”, and uses the arrow switches 38c and 38d to select the heating power P ₂ (for example, “750W”) of the grill heating unit 20. . At this time, the control circuit section 90, the driving frequency _{F D} is consistent with the resonance frequency Fr, to avoid that the switching element 71a, an excessive current 71b flows, the driving frequency in the range of about 20kHz~ about 40 kHz _{F D2} Among them, for example, control signals Sa and Sb having a maximum drive frequency of 40 kHz are supplied to the inverter circuit unit 70, and in step ST14, the load detection unit 80 detects the resonance frequency Fr ₀ g and the load resistance R (load detection). .
Alternatively, a maximum drive frequency of 80 kHz may be set as a default value for the drive frequency for performing load detection. Similarly, the load detection unit 80 initially supplies the control signals Sa and Sb having the maximum drive frequency of 40 kHz to the inverter circuit unit 70 to perform load detection, and obtains the resonance frequency Fr ₀ g. The resonance frequency Fr _{0 g} for load detection and repeated with an offset frequency ΔFrg only large driving frequency F _D2 from seeking more accurate resonance frequency Fr 1 _g, implementing the heating power P ₂ desired by the user more reliably You may do it.

In step ST15, the control circuit unit 90 has a drive frequency F _D (F _D ≧ Fr ₀ g + ΔFrg) that is higher than the resonance frequency Fr ₀ g by at least the second offset frequency ΔFrg, for example, based on the graph of FIG. arrow switches 38c, determines the driving frequency _{F D2} that heating power _{P 2} is obtained, which is selected by 38d. For example, by the user operation unit 30, as the heating power _{P 2} of the grill, for example when selecting 750W, in step ST15, the control circuit section 90 determines about 25kHz driving frequency _{F D} in the graph of FIG. 13. In step ST16, the control signal Sa having a drive frequency _{F D} of about 25kHz, is supplied to Sb in the inverter circuit unit 70, the grill heating unit 20 is controlled to 750W, whereas the power of the central IH heating portion in the vicinity of 25kHz P ₂ becomes almost zero, there is no possibility that the pot K by the central IH heating portion 10 is inductively heated be placed.

Therefore, according to the first embodiment of the present invention, when the high frequency current I is supplied to the induction heating coil 12 and the current supply coil 16 connected in parallel with each other, the induction heating coil 12 and the current supply coil 16 selected by the user are selected. Depending on (ie, induction heating mode or resistance heating mode), the driving frequency F _D1 , F _D2 of the high-frequency current I supplied from a single inverter circuit is in the range of about 50 kHz to about 80 kHz or in the range of about 20 kHz to about 40 kHz. By selecting from these, the central IH heating unit 10 (induction heating coil 12) or the grill heating unit 20 (current supply coil 16) can be selectively driven. Therefore, by sharing the inverter circuit unit 70 that drives the induction heating coil 12 and the current supply coil 16, it is possible to reduce the number of parts and to provide a cheaper induction heating cooker 1.
In the above description, when the predetermined heating powers P ₁ and P ₂ are obtained, the desired drive frequencies F _D1 and F _D2 are selected according to FIG. 13, but they are obtained from the resonance frequency Fr and the offset frequency ΔFr. and as the basic frequency drive frequency F _D, the control signal Sa, may be obtained the desired heating power by changing the duty factor of Sb.

Embodiment 2. FIG.
A second embodiment of the induction heating cooker according to the present invention will be described in detail below with reference to FIGS. 18 and 19. In the induction cooking device 1 according to the second embodiment, the central IH heating unit 10 and the grill heating unit 20 share the inverter circuit unit 70 using the individual operation units 37 and 38 and the display units 34 and 36. Since it has the same configuration as that of the heating cooker 1 according to Embodiment 1 except that it can be operated independently without making the user aware of being there, the description of the overlapping contents is omitted.

  FIG. 18 is a flowchart showing a control method of induction heating cooker 1 when the user wants to use grill heating unit 20 in a state where central IH heating unit 10 is used as described in the first embodiment. . In step ST21, when the user depresses the grill cooking operation switch (OFF / ON) 38a and selects grill cooking, in step ST22, the liquid crystal display unit 34 displays a “grill cooking menu” to set grill cooking. Or, it is displayed that the operation is possible.

In step ST23, the user selects the heating power P ₂ (for example, 750 W) of the grill cooking and grill heating unit 20 using the grill cooking operation switches 38a to 38d of FIG. Information such as the heating power P ₂ is stored in a memory (not shown) of the control circuit unit 90.

  In step ST24, when the control circuit unit 90 determines that the central IH heating unit 10 is being driven (the central IH cooking is being performed), the central IH heating is determined until it is determined that the central IH cooking has been completed (step ST26). The driving of the unit 10 is continued (step ST25).

In step ST26, the control circuit section 90, after the central IH cooking is finished, using information such as the heating power P ₂ selected at step ST23, starts the grill. In other words, the control circuit unit 90 waits for grill cooking until the central IH cooking is completed.

Thereafter, as in the first embodiment, in step ST27, the load detection unit 80 detects the load resistance R and the resonance frequency Fr ₀ g (load detection), and in step ST28, the control circuit unit 90 detects the resonance frequency. a fr ₀ g to at least a second offset frequency DerutaFrg only large driving frequency _{F D (F D ≧ fr 0} g + ΔFrg), for example based on the graph of FIG. 13, an arrow switch 38c for grilling, is selected by 38d heating power _{P 2} determines the driving frequency _{F D2} that are obtained. In addition the step ST29, the control circuit section 90, a control signal Sa having a drive frequency _{F D2} to the desired heating power _{P 2} is obtained by supplying Sb to the inverter circuit section 70, to drive the grill heating portion 20. Although not shown, thereafter, to further carry out the central IH cooking, the control circuit unit 90, the user is configured to be programmed in advance heating power P ₁ or the like using the liquid crystal display unit 34 and operation unit 30 May be.

  FIG. 19 is a flowchart showing a control method of induction heating cooker 1 when the user wants to use central IH heating unit 10 in a state where grill heating unit 20 is used as described in the first embodiment. . In step ST31, when the user depresses the central IH cooking operation switch (OFF / ON) 37a to select central IH cooking, in step ST32, the liquid crystal display unit 34 displays the “central IH menu” and displays the central IH menu. Displays that setting or operation is possible.

In step ST33, the user selects the heating power P ₁ (for example, “thermal power 2”) of the central IH heating unit 10 using the operation switches 37b and 37c for central IH cooking in FIG. The information such as the heating power P ₁ is stored in a memory (not shown) of the control circuit unit.

  In step ST34, when the control circuit unit 90 determines that the grill heating unit 20 is being driven (during grill cooking), the control circuit unit 90 drives the grill heating unit 20 until it determines that grill cooking has ended (step ST36). (Step ST35).

In step ST36, the control circuit section 90, after the grill is finished, using information such as the heating power P ₁ which is selected at step ST33, starts the central IH cooking. In other words, the control circuit unit 90 waits for central IH cooking until grill cooking is completed.

Thereafter, as in the first embodiment, in step ST37, the load detection unit 80 detects the load resistance R and the resonance frequency Fr ₀ c (load detection). In step ST38, the control circuit unit 90 detects the resonance frequency. a fr ₀ c to at least a first offset frequency DerutaFrc only large driving frequency _{F D (F D ≧ fr 0} c + ΔFrc), for example based on the graph of FIG. 13, the operation switch 37b of the center IH cooking, selected 37c The drive frequency F _D1 from which the heating power P ₁ is obtained is determined. In addition the step ST39, the control circuit section 90, a control signal Sa having a drive frequency _{F D1} to the desired heating power _{P 1} is obtained by supplying Sb to the inverter circuit unit 70 drives the central IH heating portion 10. Although not shown, the control circuit unit 90 is configured so that the user can program the heating power P _{2 and the} like in advance using the liquid crystal display unit 34 and the operation unit 30 in order to perform further grill cooking. Also good.

In the above embodiment, the control circuit unit 90 selects grill cooking by pressing the grill cooking operation switch (OFF / ON) 38a when the central IH heating unit 10 is used. when you select the heating power P ₂ of the grill and grill heating unit 20 by using the operation switch 38b~38d for grill cooking, it has been described that the central IH cooking is controlled to wait for a grill cooking to the end . However, the present invention is not limited to this, and although not shown in detail, the control circuit unit 90 selects the grill cooking by pressing the grill cooking operation switch (OFF / ON) 38a (that is, FIG. 18 between steps ST21 and ST22), the liquid crystal display unit 34 informs the user that the central IH cooking is being performed, and waits until the central IH cooking is completed or forcibly terminates the central IH cooking. Then, the user may select whether to start grill cooking.

  Further, when the user selects grill cooking by pressing the grill cooking operation switch (OFF / ON) 38a in step ST21 in a state where the central IH heating unit 10 is used, the control circuit unit 90 performs step ST22. The liquid crystal display unit 34 or the like notifies the user that the central IH cooking is being executed, and further controls not to accept the grill cooking operation. May be notified to the user to allow grill cooking.

Similarly, in the above-described embodiment, the control circuit unit 90 performs the central IH cooking by pressing the central IH cooking operation switch (OFF / ON) 37a when the grill heating unit 20 is used. selected, further central IH operation switch 37b for cooking, if you select the heating power P ₂ of the central IH heating portion 10 with 37c, as being controlled so as to wait for a central IH cooking until grill is finished explained. However, the present invention is not limited to this, and although not shown in detail, the control circuit unit 90 is configured to select the central IH cooking when the user presses the central IH cooking operation switch (OFF / ON) 37a ( That is, between steps ST31 and S32 in FIG. 19, the user is notified by the liquid crystal display unit 34 that the grill cooking is being performed, and waits until the grill cooking process is completed, or the grill cooking is forcibly terminated. Then, the user may select whether to start the central IH cooking.

  Furthermore, when the grill heating unit 20 is used, if the user selects the central IH cooking by pressing the central IH cooking operation switch (OFF / ON) 37a in step ST31, the control circuit unit 90 performs the step. Without shifting to ST32, the liquid crystal display unit 34 or the like is notified to the user that grill cooking is being performed, and further, control is performed not to accept the operation of central IH cooking. To the user and allow central IH cooking.

  As described above, the central IH cooking and grill cooking are performed alternatively, without making the user aware that the central IH heating unit 10 and the grill heating unit 20 share the single inverter circuit unit 70. The induction heating cooker 1 with high user convenience that can be realized can be realized.

Embodiment 3 FIG.
A third embodiment of the induction heating cooker according to the present invention will be described below in detail with reference to FIGS. The induction heating cooker 1 according to the second embodiment operates the central IH heating unit 10 and the grill heating unit 20 alternatively or continuously without making the user aware that the inverter circuit unit 70 is shared. Whereas the induction heating cooker 1 according to the third embodiment is configured to be able to operate the central IH heating unit 10 and the grill heating unit 20 at the same time, the induction heating cooker 1 according to the third embodiment relates to the second embodiment. Since it has the same configuration as the heating cooker 1, the description of the overlapping contents is omitted.

The control circuit unit 90 according to the second embodiment has an inverter circuit unit so that a constant and continuous high-frequency current for obtaining desired power flows only in either the central IH heating unit 10 or the grill heating unit 20. 70 was controlled. FIG. 20B is a waveform diagram showing control signals Sa and Sb supplied to the switching elements 71a and 71b of the inverter circuit unit 70 in order to drive the central IH heating unit 10, and the drive frequency _FD1 is about 50 kHz. Is in the range of ~ 80 kHz. On the other hand, FIG. 20A is a waveform diagram showing the control signals Sa and Sb supplied to the switching elements 71a and 71b of the inverter circuit unit 70 in order to drive the grill heating unit 20, and the drive frequency _FD2 is about It is in the range of 20 kHz to about 40 kHz. FIG. 20C shows a period T ₁ during which the inverter circuit unit 70 according to the third embodiment supplies a high-frequency current having a drive frequency F _D1 to the induction heating coil 12 and the current supply coil 16, and a drive frequency F _D2 . is a timing chart showing the period T ₂ for supplying a high-frequency current to the induction heating coil 12 and the current supply coil 16.

The control circuit unit 90 according to the third embodiment, the high frequency current _{I 1} having a drive frequency _{F D1} in the driving period _{T 1,} a high-frequency current _{I 2} having a drive frequency _{F D2} are in the driving period _{T 2,} the induction heating The inverter circuit unit 70 is controlled so as to be periodically supplied to the coil 12 and the current supply coil 16. That central IH heating unit 10 is driven by the high-frequency current _{I 1} having a drive frequency _{F D1} in the driving period _{T 1, (T 1 / T} 1 + T 2) of the heating power _{P 1} is determined from the graph of FIG. 13 Double firepower can be obtained. Similarly, the grill heating unit 20 is driven by the high-frequency current _{I 2} having a drive frequency _{F D2} in the driving period _{T 2,} the heating power _{P 2} is determined from the graph of FIG. _{13 (T 2 / T 1 +} T 2 ) Double firepower can be obtained. That is, the control circuit unit 90 according to the third embodiment appropriately selects the driving frequencies F _D1 and F _D2 and the driving periods T ₁ and T ₂ to which the high-frequency currents I ₁ and I ₂ are supplied, so that the central IH Arbitrary heating power P ₁ ′ (= P ₁ × (T ₁ / T ₁ + T ₂ )), P ₂ ′ (= P ₂ × (T ₂ / T ₁ + T) desired by the heating unit 10 and the grill heating unit 20 ₂ )) can be controlled to output the inverter circuit unit 70.

In this way, the load detection unit 80 detects the resonance frequencies Fr ₀ c ′ and Fr ₀ g ′ by detecting the load, and the central IH heating unit 10 and the grill heating unit 20 obtain desired heating powers P ₁ ′ and P ₂ ′. In order to output, the control circuit unit 90 sets an appropriate drive frequency F _D1 , F _D2 and drive period T ₁ , T ₂ in the present specification simply “drive frequency of the high-frequency currents I ₁ , I ₂ . / Simultaneous setting of driving period ", the central IH heating unit 10 is used to induction-heat the pan K on the top plate 3 to cook the ingredients in the pan K, and at the same time, the grill heating unit 20 is used to heat the heaters 22a, 22a, Cooking the ingredients in the heating chamber 21 by resistance heating 22b is referred to as “simultaneous heating mode”.

Further, as described above in the second embodiment, the load detection unit 80 detects the resonance frequencies Fr ₀ c ′ and Fr ₀ g ′ by detecting the load, and either the central IH heating unit 10 or the grill heating unit 20 is detected. In order to continuously supply the high-frequency currents I ₁ and I ₂ and alternatively output the desired heating powers P ₁ ′ and P ₂ ′, the control circuit unit 90 has appropriate drive frequencies F _D1 and F 2. Setting _D2 is referred to as “individual setting of driving frequencies of high-frequency currents I ₁ and I ₂ ” in the present specification.

FIG. 21 is a flowchart showing a control method of induction heating cooker 1 when the user wants to use central IH heating unit 10 in a state where grill heating unit 20 is used. FIG. 22 shows a period T ₁ in which the inverter circuit unit 70 supplies a high-frequency current having the driving frequency F _D1 to the central IH heating unit 10 when the simultaneous heating mode is entered from the state where the central IH heating unit 10 is used. When is a high-frequency current having the drive frequency F _D2 timing charts showing the period T ₂ to be supplied to the grill heating unit 20. In step ST41 of the flowchart of FIG. 21, the user is performing grill cooking using the operation unit 30 (drive frequency F _D2 and heating power P ₂ during grill cooking in FIG. 22). Thereafter, in step ST42, the user further performs central IH cooking using the operation unit 30. At this time, in step ST43, the control circuit 90 determines whether or not grill cooking is being performed, that is, whether or not grill cooking is being performed.

When grill cooking is being performed, in step ST44, the control circuit 90 performs simultaneous setting of the driving frequency / driving period of the high-frequency currents I ₁ and I ₂ to be supplied to the central IH heating unit 10 and the grill heating unit 20, In order to obtain the heating powers P ₁ ′ and P ₂ ′ of the central IH heating unit 10 and the grill heating unit 20 set by the operation unit 30, appropriate driving frequencies F _D1 and F _D2 and driving periods T ₁ and T ₂ are determined. Then, the central IH heating unit 10 and the grill heating unit 20 are simultaneously driven (the driving frequency F _D2 ′, the heating power P ₂ ′, the driving frequency F _D1 , and the heating power P _{1 in} FIG. 22).

On the other hand, if it is not being grill execution, in step ST45, the control circuit section 90 includes a central IH perform individual setting of the driving frequency of the high frequency current I ₁ to be supplied to the heating unit 10, the set central IH operation unit 30 In order to obtain the heating power P ₁ of the heating unit 10, an appropriate drive frequency FD ₁ is determined and the inverter circuit unit 70 is controlled. In step ST46, the control circuit unit 90 determines whether or not the central IH cooking is being performed, that is, whether or not the central IH cooking is being performed, and continues the central IH cooking until the central IH cooking is stopped ( FIG. 22 shows the driving frequency F _D1 ′ and heating power P ₁ ′ during IH cooking.

The control circuit unit 90 always monitors whether grill cooking is being performed in step ST47 and whether central IH cooking is being performed in step ST48. If it is determined in step ST47 that grill cooking is not being performed, the process proceeds to step ST45. In step ST48, the control circuit section 90, albeit in a grill execution, if it is found not to be in the center IH cooking executed, the process proceeds to step ST 49, the driving frequency of the high frequency current I ₂ to be supplied to the grill heating section 20 make individual settings, to determine the appropriate driving frequency F _D2 in order to obtain the heating power P ₂ of grill heating portion 20 which is set by the operation unit 30, controls the inverter circuit 70. In step ST50, the control circuit unit 90 determines whether grill cooking is being performed, and continues grill cooking until grill cooking is stopped.

When control circuit unit 90 determines in steps ST47 and 48 that both grill cooking and central IH cooking are being performed (simultaneous heating mode), heating power P ₁ of central IH heating unit 10 is determined in step ST51. It is determined that 'is changed to heating power P ₁ ″ by the user using the operation unit 30 or heating power P ₂ ′ of the grill heating unit 20 is changed to heating power P ₂ ″. When the control circuit unit 90 determines that the heating power of the central IH heating unit 10 or the grill heating unit 20 has been changed, the control circuit unit 90 returns to step ST44 and again supplies the high frequency to be supplied to the central IH heating unit 10 and the grill heating unit 20. The drive frequency / drive period of the currents I ₁ and I ₂ are set simultaneously, and the newly set combination of heating power (P ₁ ′ and P ₂ ″, P ₁ ″ and P ₂ ′, or P ₁ ′) ′ And P ₂ ″) are determined to determine appropriate driving frequencies F _D1 and F _D2 and driving periods T ₁ and T ₂ to drive the central IH heating unit 10 and the grill heating unit 20 simultaneously (FIG. 22). (Not shown).

Note that step ST51 for determining whether the heating power P ₁ ′ of the central IH heating unit 10 or the heating power P ₂ ′ of the grill heating unit 20 has been changed by the user using the operation unit 30 is performed in step ST47 or step ST51. It may be performed after ST48. Further, the control circuit 90 determines whether or not the heating power P ₂ ′ of the grill heating unit 20 has been changed after step ST47, and whether or not the heating power P ₁ ′ of the central IH heating unit 10 has been changed after step ST48. When it is determined whether or not, the process returns to step ST44 to again set the driving frequency / driving period of the high-frequency currents I ₁ and I ₂ to be supplied to the central IH heating unit 10 and the grill heating unit 20 again. the combination of heating power set to _{(P 1} 'and _{P 2'', P 1'} ' and _{P 2',} or P _{1 ''} and _{P 2} '') suitable drive frequency to obtain the _F D1, F _The central IH heating unit 10 and the grill heating unit 20 may be driven simultaneously by determining _D2 and the driving periods T ₁ and T ₂ .

  As described above, according to the induction heating cooker 1 according to the third embodiment, in the simultaneous heating mode, the pot K on the top plate 3 is induction-heated using the central IH heating unit 10 to heat the pot K in the pot K. At the same time as cooking the ingredients, the heaters 22a and 22b are resistance-heated using the grill heating unit 20, whereby the ingredients in the heating chamber 21 can be cooked, and the convenience for the user can be greatly improved.

DESCRIPTION OF SYMBOLS 1 ... Induction cooking device, 2 ... Housing, 3 ... Top plate, 4 ... IH heating part, 5a ... Exhaust port, 5b ... Intake port, 10 ... Central IH heating part, 12 ... Induction heating coil, 13 ... Coil base , 14 ... Magnetic body (ferrite core), 15 ... Coil unit, 16 ... Planar coil (current supply coil), 17 ... Thermal insulation substrate, 18 ... Magnetic body, 19 ... Aluminum cover (cancellation cover), 20 ... Grill heating part, DESCRIPTION OF SYMBOLS 21 ... Heating chamber, 22 ... Heater, 23a ... Upper wall, 23b ... Lower wall, 23c ... Front door, 23d ... Rear wall, 24 ... Recessed part, 26 ... Slide rail, 27 ... Receptacle, 28 ... Grilling net, 30 ... Operation Part (operation panel), 31 ... thermal power adjustment dial, 34 ... LCD display part, 36 ... LED display part, 50 ... power supply circuit part, 51 ... converter, 52 ... filter circuit, 70 ... inverter circuit part, 71 ... Switching element, 72 ... FWD element, 75 ... resonant capacitor, 76 ... resonant circuit, 77 ... protection components, 78 ... load detecting means, 80 ... load detection section, 90 ... control circuit, 100 ... cancel ring, K ... pot.

Claims (10)

A top plate on which the object to be heated is placed;
An induction heating coil that induction-heats the heated object placed on the top plate when a high-frequency current is supplied;
A heating chamber provided below the top plate, and having a heat insulating substrate provided with a plurality of recesses on the inside as a rear wall, and
A plurality of heaters made of electrically closed conductors detachably disposed in the plurality of recesses provided on the heat insulating substrate;
When a high frequency current is supplied, a current supply coil for resistance heating the plurality of heaters by forming a high frequency magnetic flux interlinking with the plurality of heaters and supplying the high frequency current to the plurality of heaters;
A U-shaped or U-shaped magnetic body disposed so as to surround at least a part of the current supply coil and cover the concave portion of the heat insulating substrate;
An inverter circuit for supplying a high-frequency current to the induction heating coil and the current supply coil;
With
The current supply coil and the induction heating coil are connected in parallel to each other;
Induction heating cooker characterized by. An aluminum cover covering the current supply coil and the magnetic body;
The induction heating cooker according to claim 1. A cooling fan for sending cooling air;
The aluminum cover functions as a wind tunnel for cooling air sent from the cooling fan, and cools the magnetic body and the current supply coil covered with the aluminum cover;
The induction heating cooker according to claim 2 characterized by things. A load detection unit that detects the presence or absence of the heater in the recess of the heat insulating substrate by detecting a resonance frequency and a load resistance of a resonance circuit including the induction heating coil and the current supply coil;
The induction heating cooker according to any one of claims 1 to 3, wherein: Depending on the detection result by the load detection unit, controlling the driving frequency or on / off of the switching element of the inverter circuit,
The induction heating cooker according to claim 4. An operation unit that allows the user to select either a) induction heating mode for induction heating of the object to be heated, or b) resistance heating mode for resistance heating of the heater;
A control circuit unit that controls a driving frequency (F _D1 , F _D2 ) of a high-frequency current supplied from the inverter circuit to the induction heating coil and the current supply coil according to the heating mode selected in the operation unit;
The induction heating cooker according to any one of claims 1 to 5, wherein the induction heating cooker is provided. The control circuit unit is
a) controlling the inverter circuit so that a high-frequency current having a first drive frequency (F _D1 ) is supplied from the inverter circuit to the induction heating coil and the current supply coil in the induction heating mode;
b) In the resistance heating mode, a high-frequency current having a second drive frequency (F _D2 ) lower than the first drive frequency (F _D1 ) is supplied from the inverter circuit to the induction heating coil and the current supply coil. The induction heating cooker according to claim 6, wherein the inverter circuit is controlled as described above. A load detection unit electrically connected to the control circuit unit;
a) In the induction heating mode,
The load detection unit detects a first resonance frequency (Fr ₁ ) when a high-frequency current is supplied from the inverter circuit to the induction heating coil and the current supply coil,
The control circuit unit determines the first drive frequency (F _D1 ) so as to be higher than the first resonance frequency (Fr ₁ ) by the addition frequency (ΔF ₁ ),
b) In the resistance heating mode,
The load detection unit detects a second resonance frequency (Fr ₂ ) when a high-frequency current is supplied from the inverter circuit to the induction heating coil and the current supply coil,
The control circuit unit determines the second drive frequency (F _D2 ) so as to be higher than the second resonance frequency (Fr ₂ ) by the addition frequency (ΔF ₂ ). Induction heating cooker. The operation unit is configured so that a user can select a simultaneous heating mode in which c) the object to be heated is induction-heated and the heater is resistance-heated,
c) In the simultaneous heating mode,
The operation unit can set a first heating power (P ₁ ) supplied by the induction heating coil and a second heating power (P ₂ ) supplied by the current supply coil by a user,
The control circuit unit generates a high-frequency current having a first drive frequency (F _D1 ) from the inverter circuit according to the first and second heating powers (P ₁ , P ₂ ) from the inverter circuit and the current supply. A high frequency current having a _first drive period (T ₁ ) supplied to the coil and a second drive frequency (FD ₂ ) is supplied from the inverter circuit to the induction heating coil and the current supply coil. The driving period (T ₂ ) is determined, and the first and second driving periods (T ₁ , T ₂ ) are alternately changed so that a high-frequency current is supplied to the induction heating coil and the current supply coil. The induction heating cooker according to claim 8, wherein the inverter heating circuit is controlled. First and second resonant frequency _{(Fr 0 c, Fr 0 g} ) the difference is, the induction heating cooker according to any one of claims 6-9, wherein greater than the audible frequency.

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