JP2013179077A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating cooker which includes a central heating coil and a plurality of peripheral heating coils arranged adjacent to the central heating coil and each having an arc shape following the shape of the central heating coil; and which can achieve various kinds of useful cookery by flexibly switching a mode between a mode of weakening magnetic flux with each other and a mode of heightening magnetic flux with each other by using direction switching means.SOLUTION: An induction heating cooker of the present embodiment comprises: a central heating coil: a plurality of peripheral heating coils which are arranged adjacent to and on the periphery of the central heating coil and each of which has an arc shape following the shape of the central heating coil; a plurality of power supply circuit parts for supplying high-frequency current to each of the heating coils; a control circuit part for controlling the plurality of power supply circuit parts; and direction switching means for switching a heating mode in a region where the central heating coil and the plurality of peripheral heating coils are adjacent to each other between a first heating mode of supplying the high-frequency current to the central heating coil and the plurality of peripheral heating coils in the same direction and a second heating mode of supplying the high-frequency current in opposite directions.

Description

  The present invention relates to an induction heating cooker having a plurality of induction heating coils.

  For example, a conventional induction heating cooker described in Patent Document 1 includes a plurality of heating coils that are magnetically coupled and a plurality of inverter circuits that supply a high-frequency current to each heating coil. By controlling the phase difference between the heating coils and adjusting the mutual inductance between the heating coils, it is possible to heat a heated pan having a large skin resistance, such as an iron pan and an aluminum pan, to the same extent.

  More specifically, the induction heating cooker of Patent Document 1 is an inverter so that a current in the same direction is supplied to adjacent heating coils for a heated pan of a low resistance pan such as an aluminum pan. By controlling the circuit, the mutual inductance acts positively, the effective inductance of the heating coil is increased, and the current flowing through the heating coil is suppressed. On the other hand, this induction heating cooker controls the inverter circuit so that a reverse current is supplied to the adjacent heating coils for a heated pan such as an iron pan or a magnetic SUS pan. By doing so, the mutual inductance acts negatively, the effective inductance of the heating coil is reduced, and the current is easily passed through the heating coil.

  That is, according to the induction heating cooker of Patent Document 1, by switching the direction of the current supplied to the adjacent heating coils based on the constituent material of the heated pan, the iron pan having a large difference in skin resistance and Both aluminum pans can be heated efficiently.

JP 2007-12482 A

  However, according to the induction heating cooker described in Patent Literature 1, during cooking, that is, while high-frequency current is supplied to each heating coil, if the direction of the energization current flowing through the adjacent heating coils is the same direction, If it is in the reverse direction, it remains fixed in the reverse direction. Therefore, when the direction of the energization current is the same direction (in the opposite direction in the adjacent areas of the heating coil), the magnetic fluxes generated from the adjacent heating coils cancel each other and the heating efficiency is reduced. When the direction of the current is the opposite direction (the same direction in the adjacent region), the magnetic fluxes generated from the adjacent heating coils strengthen each other, and only the heated pan at the top of the adjacent region of each heating coil There is a problem that heating is excessively performed (overheated) as compared with other regions, resulting in uneven heating.

  Accordingly, the present invention has been made to solve the above-described problems, and is disposed so as to be adjacent to the central heating coil wound around a plane and the periphery of the central heating coil. A plurality of peripheral heating coils having an arcuate shape, a plurality of power supply circuit units for supplying a high-frequency current to each of the central heating coil and the plurality of peripheral heating coils, and a control circuit for controlling the plurality of power supply circuit units A first heating mode for flowing the high-frequency current in the same direction, or a second flow for flowing the high-frequency current in the reverse direction in a region where the central heating coil and each of the plurality of peripheral heating coils are adjacent to each other An induction heating cooker provided with a direction switching means for switching to a heating mode is provided.

  According to the present invention, in an induction heating cooker having a central heating coil and a plurality of peripheral heating coils arranged adjacent to the periphery of the central heating coil and having an arc shape along the central heating coil, the direction switching means is used. Thus, various useful cooking methods can be provided by freely selecting a uniform heating mode for uniformly heating the heated body and a high efficiency heating mode for heating the heated body with high heat generation efficiency. .

1 is a perspective view illustrating a schematic mechanical configuration of an induction heating cooker according to the present invention. It is sectional drawing seen from the II-II line of FIG. It is a block diagram which shows the electrical structure of the induction heating cooking appliance of Embodiment 1. FIG. It is a specific circuit wiring diagram of the induction heating cooking appliance of Embodiment 1. FIG. It is a top view of the heating coil of FIG. 1, (a) is a high efficiency heating mode, (b) shows the electric current which flows into a heating coil when it drives by a uniform heating mode. (A) A gate signal for each switching element and (b) a high frequency current supplied to the heating coil in the high efficiency heating mode. (A) A gate signal for each switching element and (b) a high-frequency current supplied to the heating coil in the uniform heating mode. FIG. 6 is a plan view of a heating coil according to a modification of the first embodiment. It is a top view of the heating coil similar to FIG. 8, (a) shows the high current heating mode, (b) shows the electric current which flows into a heating coil when it drives by a uniform heating mode. It is a block diagram which shows the electric constitution of the induction heating cooking appliance of Embodiment 2. It is a block diagram which shows the electric constitution of the induction heating cooking appliance of Embodiment 3. It is a block diagram which shows the electric constitution of the induction heating cooking appliance of Embodiment 4. It is a block diagram which shows the electric constitution of the induction heating cooking appliance of Embodiment 5. It is a block diagram which shows the electric constitution of the induction heating cooking appliance of Embodiment 6.

  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, a term indicating a direction (for example, “upward” and “downward”) is used as appropriate for easy understanding. Does not limit the present 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 illustrating a schematic mechanical configuration of an induction heating cooker 1 according to the present invention. 2 is a cross-sectional view taken along line II-II in FIG. An induction heating cooker 1 shown in FIG. 1 includes a top plate 8 on which a heated object P such as a pan is placed, and a plurality of (two in FIG. 1) heating coils 10a and 10b disposed below the top plate 8. Each of the heating coils 10a and 10b is electrically and mechanically connected, and has a plurality of (two in FIG. 1) drive circuits 20a and 20b for independently supplying a high frequency current of several tens of kHz. When a high frequency current is supplied to each of the heating coils 10a and 10b, an alternating magnetic field is formed around the heating coils 10a and 10b (the alternating magnetic field is linked to the heated body P made of a conductor), and an eddy current is applied to the heated body P. Then, the heated object P itself is heated.
In addition, although each heating coil 10a, 10b of FIG. 1 is illustrated as having a rectangular planar shape, it is not limited to this and has an arbitrary planar shape such as an elliptical shape or a semicircular shape. It may be.

  FIG. 3 is a block diagram showing an electrical configuration of induction heating cooker 1 according to the first embodiment. FIG. 4 shows specific circuit wiring of the block diagram of the induction heating cooker 1 shown in FIG. 3, but is not limited to this, and other circuits that can be easily devised by those skilled in the art. Wiring can be employed. In order to facilitate understanding, the induction heating cooker 1 according to Embodiment 1 will be described below with reference to FIGS. 3 and 4.

  As shown schematically in FIG. 3 and FIG. 4, the induction heating cooker 1 according to the present invention includes a two-phase or three-phase commercial AC power source 30, rectifiers 21 a and 21 b that convert the AC power source 30 into a DC current, and each Drive circuits 20a and 20b including inverters 22a and 22b for supplying high-frequency current to the heating coils 10a and 10b, and an input-side current sensor (input side) for detecting currents input to and output from the heating coils 10a and 10b Current transformers) 40a and 40b and output-side current sensors (output-side current transformers) 42a and 42b.

  Moreover, the induction heating cooker 1 which concerns on Embodiment 1 is arrange | positioned under the top plate 8, the temperature sensor 50 for measuring the temperature of the to-be-heated body P, the temperature measured with the temperature sensor 50, and A control circuit 15 is provided that receives information on currents detected by the input-side current transformers 40a and 40b and the output-side current transformers 42a and 42b and controls the drive circuits 20a and 20b.

  As shown in FIG. 4, each rectifier 21a, 21b has diode bridges 23a, 23b and smoothing capacitors 24a, 24b, for example. Each inverter 22a, 22b includes a pair of switching elements (eg, insulated gate bipolar transistors) 27a, 28a, 27b, 28b in which reflux diodes (eg, freewheel diodes) 25a, 26a, 25b, 26b are reversely connected in parallel; Drivers 29a and 29b that supply gate signals to the gates of the respective switching elements 27a, 28a, 27b, and 28b under the control of the control circuit 15 are provided.

  The high-frequency current output from each inverter 22a, 22b is supplied to each heating coil 10a, 10b (illustrated as an equivalent circuit of inductance and resistance in FIG. 4) via resonant capacitors 31a, 31b. As described above, the information on the current values on the input side and the output side detected by the input side current transformers 40 a and 40 b and the output side current transformers 42 a and 42 b is transmitted to the control circuit 15. At this time, based on these current values, the control circuit 15 determines whether the heated object P is placed on the top plate (whether the heated object P is placed out of the center position or not). The size of the heating body P can be detected, and the gate signals of the inverters 22a and 22b are appropriately controlled in accordance with the detection results to supply appropriate high-frequency currents to the heating coils 10a and 10b. it can.

  The control circuit 15 can control the high-frequency current output from each inverter 22a, 22b, for example, by adjusting the ON time of the gate signal, and thus adjusts the high-frequency current supplied to each heating coil 10a, 10b. Thereby, the heating power of the to-be-heated body P heated by each heating coil 10a, 10b is controllable.

  The gate signals of the inverters 22a and 22b controlled by the control circuit 15 may have the same ON / OFF timing (phase) or may be different, and are arbitrarily controlled using the control circuit 15. be able to. That is, the control circuit 15 makes the ON / OFF timing of the gate signal the same, the direction of the current flowing in each of the heating coils 10a and 10b is the same direction, and the ON / OFF timing of the gate signal is opposite to each other, The direction of the current flowing through each heating coil 10a, 10b can be controlled in the opposite direction.

  5 (a) and 5 (b) are plan views of the heating coils 10a and 10b when the top plate 8 of FIG. 1 is removed as viewed from above, and FIG. FIG. 5 (b) shows the state when the direction of the current flowing through the heating coils 10a and 10b is controlled to be the same direction so that the direction of the current flowing through the coils 10a and 10b is opposite. It is. A broken line P in 5 (a) and FIG. 5 (b) indicates an arrangement position of the body P to be heated.

  In FIG. 5 (a), since each of the heating coils 10a and 10b has a current in the reverse direction as a whole, the adjacent region (the region surrounded by the one-dot chain line 52) has the same direction (from top to bottom in the drawing). Direction) current flows. That is, each heating coil 10a, 10b can mutually strengthen the magnetic flux in the region 52 adjacent to each other, increase the magnetic flux density interlinking the pan P, and can heat the pan P with high efficiency. In the present invention, as shown in FIG. 5A, the driving mode for controlling the currents in the same direction to flow in the adjacent regions 52 of the heating coils 10a and 10b is referred to as a “high efficiency heating mode” for convenience of explanation below.

  On the other hand, in FIG. 5B, when the heating coils 10a and 10b are controlled so as to flow in the same direction (both clockwise in the figure), the magnetic fluxes cancel each other in the adjacent regions 52. Since the density is reduced and the magnetic flux density in the adjacent region 52, which originally has the highest magnetic flux density, is suppressed to a low level, the magnetic flux that interlinks the pan P in the wide area indicated by the two-dot chain line 54 in FIG. Distribution becomes uniform. Similarly, in the present invention, as shown in FIG. 5B, the driving mode for controlling the current in the reverse direction to flow in the adjacent regions 52 of the heating coils 10a and 10b is referred to as “uniform heating mode” for convenience of explanation below. .

In the high-efficiency heating mode of FIG. 5A, as described above, the pan P can be heated with high heat generation efficiency, so that cooking time can be shortened and power consumption can be saved, while partial adjacency is achieved. Since it is heated strongly in the region 52, uneven heating occurs, and depending on the food contained in the pan P, partial burning may occur.
On the other hand, in the uniform heating mode of FIG. 5B, the concentration of magnetic flux can be suppressed and the burning of food can be prevented, but the cooking time tends to be long.

  The induction heating cooker 1 according to the first embodiment uses the temperature sensor 50 arranged below the top plate 8 to measure the temperature of the heated object P, and according to the temperature measured by the temperature sensor 50, The high-efficiency heating mode and the uniform heating mode can be arbitrarily switched. Specifically, according to the induction heating cooker 1 according to the first embodiment, the control circuit 15 assumes that the possibility of scorching of food is low until the measured temperature of the heated object P reaches a predetermined temperature. The pan P is efficiently heated in the high-efficiency heating mode. When the pan P exceeds a predetermined temperature, the pan P is automatically switched to the uniform heating mode to control the drive circuits 20a and 20b so as to suppress the heating unevenness. . That is, the control circuit 15 according to the first embodiment uses the high-efficiency heating mode until, for example, the temperature reaches 100 ° C. when sufficient convection occurs in the food (water) and it is difficult to cause uneven heating, such as when boiling hot water. After heating and reaching 100 ° C., the inverter 22a, 22b may be controlled by switching to the uniform heating mode.

  That is, in the temperature sensor 50 according to the first embodiment, in the adjacent regions 52 of the heating coils 10a and 10b, the high-efficiency heating mode in which the high-frequency current flows in the same direction (FIG. 5A) or the high-frequency current is in the reverse direction It functions as a component of the direction switching means for switching to the uniform heating mode (FIG. 5 (b)) flowing through.

The high-efficiency heating mode and the uniform heating mode can be realized by an arbitrary method using the control circuit 15. 6 and 7 show gate signals for the switching elements 27a, 28a, 27b, and 28b and high-frequency currents supplied to the heating coils 10a and 10b in the high-efficiency heating mode and the uniform heating mode, respectively.
For example, the gate signals of the high-voltage side and low-voltage side switching elements 27a, 28a of one heating coil 10a are inverted from the gate signals of the high-voltage side and low-voltage side switching elements 27b, 28b of the other heating coil 10b. ) (FIG. 6A), the high-efficiency heating mode can be easily realized with the timing of the high-frequency current supplied to each of the heating coils 10a and 10b as the opposite phase (FIG. 6B).
Further, the gate signals of the high voltage side and low voltage side switching elements 27a, 28a of one heating coil 10a and the gate signals of the high voltage side and low voltage side switching elements 27b, 28b of the other heating coil 10b are synchronized (with the same phase). (FIG. 7A), the uniform heating mode can be implemented with the timing of the high-frequency current supplied to the heating coils 10a and 10b as the same phase (FIG. 7B).

(Modification)
In Embodiment 1, although induction heating cooker 1 explained as what has two heating coils 10a and 10b, it is not limited to this, and with respect to induction heating cooking appliances which have many more heating coils. The present invention can also be applied in the same manner.

FIG. 8 is a plan view similar to FIG. 5 showing an induction heating cooker having a central coil 12 and four satellite coils 14a to 14d. The center coil 12 and the satellite coils 14a to 14d may be connected to independent drive circuits 20, respectively. The central coil 12 may be constituted by an inner coil 12a and an outer coil 12b, and the inner coil 12a and the outer coil 12b may be connected in series (FIG. 8) or in parallel. It may be connected to (not shown).
In addition, the satellite coils 14a to 14d are not connected to the independent drive circuits 20, but all of the satellite coils 14a to 14d or some of the satellite coils 14a to 14d are connected in series or in parallel. A satellite coil connected in series or in parallel may be connected to one drive circuit 20.

  In any case, according to the induction heating cooker 1 according to the present invention, as shown in FIG. 9, when the temperature of the pan P is measured using the direction switching means composed of the temperature sensor 50 and a predetermined condition is satisfied. Can switch the direction in which the high-frequency current flows in the region where the central coil 12 and the satellite coils 14a to 14d are adjacent to each other between the same direction (high efficiency heating mode) or the reverse direction (uniform heating mode). . Thus, the control circuit 15 switches the high-efficiency heating mode or the uniform heating mode based on the temperature of the pan P and controls the drive circuit 20 to prevent the food from being burnt and to efficiently heat the pan P. Can do.

Embodiment 2. FIG.
A second embodiment of the induction heating apparatus according to the present invention will be described below with reference to FIG. The induction heating device 2 according to the second embodiment has the same configuration as that of the induction heating device 1 except that the timer 60 is used instead of the temperature sensor 50 as the direction switching means. The detailed description to be omitted is omitted. In the figure, the same components are denoted by the same reference numerals.

  The timer 60 of the induction heating device 2 according to Embodiment 2 measures the cooking time from when cooking is started, and transmits the cooking time information to the control circuit 15. The control circuit 15 of the second embodiment switches to the high efficiency heating mode or the uniform heating mode based on the cooking time measured by the timer 60. For example, the control circuit 15 controls the inverters 22a and 22b until the cooking time measured by the timer 60 has elapsed for 3 minutes, that is, until the initial heating time has elapsed, so that each of the heating coils 10a and 10b in the high-efficiency heating mode. May be driven. Thus, until the initial heating time has elapsed, the temperature of the pan P is often not so high, so that heating is performed in the high-efficiency heating mode within the initial heating time, and heating unevenness occurs after the initial heating time. Since it may cause a problem, it is preferable to heat by switching to the uniform heating mode.

Embodiment 3 FIG.
A third embodiment of the induction heating apparatus according to the present invention will be described below with reference to FIG. The induction heating device 3 according to the third embodiment has the same configuration as that of the induction heating device 1 except that the electric energy measuring unit 62 is used instead of using the temperature sensor 50 as the direction switching unit. Detailed descriptions related to the parts are omitted. In the figure, the same components are denoted by the same reference numerals.

  The electric energy measuring means 62 measures the input electric energy from the commercial power supply 30 and transmits it to the control circuit 15 as electric energy information. The control circuit 15 according to the third embodiment switches to the high efficiency heating mode or the uniform heating mode based on the amount of power measured by the power amount measuring means 62. Specifically, when the heating coils 10a and 10b are driven in the high-efficiency heating mode, if the amount of power that is actually consumed becomes larger than the maximum power consumption, the control circuit 15 You may make it switch to uniform heating mode. Further, when the actual power consumption is sufficiently small, the control circuit 15 may perform control so as to switch to the high-efficiency heating mode that requires large power consumption.

Embodiment 4 FIG.
Embodiment 4 of the induction heating apparatus according to the present invention will be described below with reference to FIG. The induction heating apparatus 4 according to the fourth embodiment uses the induction heating apparatus 1 except that the heating mode setting means 64 capable of manually switching the heating mode by the user is used instead of using the temperature sensor 50 as the direction switching means. The detailed description related to the other components is omitted. In the figure, the same components are denoted by the same reference numerals.

  The heating mode setting means 64 enables switching to the high efficiency heating mode or the uniform heating mode by a user operation, and transmits the setting information to the control circuit 15. The control circuit 15 of the fourth embodiment switches to the high efficiency heating mode or the uniform heating mode set by the heating mode setting means 64. Therefore, according to the induction heating device 4 according to the fourth embodiment, it is possible to freely switch to the high-efficiency heating mode or the uniform heating mode by a user operation.

Embodiment 5 FIG.
A fifth embodiment of the induction heating apparatus according to the present invention will be described below with reference to FIG. The induction heating device 5 according to the fifth embodiment has the same configuration as that of the induction heating device 1 except that the menu selection unit 66 is used instead of the temperature sensor 50 as the direction switching unit. Detailed description related to is omitted. In the figure, the same components are denoted by the same reference numerals.

  Using the menu selection means 66 of the fifth embodiment, the user can select a cooking menu such as “eggaki” or “water heater”. For example, when “eggaki” is selected by the menu selection means 66, the control circuit 15 switches to the uniform heating mode in order to heat the frying pan P as a whole, and when “water heater” is selected, Since there is no fear, the inverters 22a and 22b are controlled to heat in the high efficiency heating mode. When “eggaki” is selected by the menu selection means 66, during the first preheating (for example, 1 minute after the start of cooking), heating is performed in the high-efficiency heating mode, and then switching to the uniform heating mode is performed to suppress scorching. Thus, the control circuit 15 is preferably programmed in advance.

Embodiment 6 FIG.
Embodiment 6 of the induction heating apparatus according to the present invention will be described below with reference to FIG. The induction heating device 6 according to the sixth embodiment has the same configuration as the induction heating device 1 except that the automatic processing function selection unit 68 is used instead of the temperature sensor 50 as the direction switching unit. Detailed descriptions related to the components are omitted. In the figure, the same components are denoted by the same reference numerals.

  An arbitrary cooking procedure (heating procedure) can be input as a cooking program in advance using the automatic processing function selection means 68 of the sixth embodiment. For example, the control circuit 15 heats for 3 minutes after starting cooking in the high efficiency heating mode, then switches to the uniform heating mode and heats for 3 minutes, switches to the high efficiency heating mode again and heats for 1 minute, repeats this, etc. By programming, the drive circuits 20a and 20b can be controlled so as to heat with high efficiency while preventing scorching.

  The direction switching means according to the above embodiment can be arbitrarily combined. That is, the direction switching means includes a temperature sensor 50 for measuring the temperature of the pan P, a timer 60 for measuring cooking time, an electric energy measuring means 62 for measuring the input electric energy, a heating mode setting means 64, and a menu. An arbitrary combination of the selection means 66 and the automatic processing function selection means 68 is used, and the control circuit 15 switches to the high efficiency heating mode or the uniform heating mode based on various information from these direction switching means. Or may be configured.

1 to 6: induction heating cooker, 8: top plate, 10: heating coil, 12: central coil, 14: satellite coil, 15: control circuit, 20: drive circuit, 21: rectifier, 22: inverter, 23: diode Bridge, 24: Smoothing capacitor, 25, 26: Freewheeling diode, 27, 28: Switching element, 29: Driver, 30: Commercial AC power supply, 31: Resonant capacitor, 40: Input side current transformer, 42: Output side current transformer, 50: Temperature sensor, 52: Adjacent region, 60: Timer, 62: Electric energy measuring means, 64: Heating mode setting means, 66: Menu selection means, 68: Automatic processing function selection means, P: Object to be heated.

Claims (7)

A central heating coil wound in a plane,
A plurality of peripheral heating coils disposed adjacent to the periphery of the central heating coil and having an arc shape along the central heating coil;
A plurality of power supply circuit sections for supplying a high-frequency current to the central heating coil and each of the plurality of peripheral heating coils;
A control circuit unit for controlling the plurality of power supply circuit units;
In a region where the central heating coil and each of the plurality of peripheral heating coils are adjacent to each other, the first heating mode in which the high-frequency current flows in the same direction, or the second heating mode in which the high-frequency current flows in the reverse direction An induction heating cooker comprising a direction switching means for switching. The direction switching means has a timer for measuring time,
The induction heating cooking according to claim 1, wherein the control circuit unit controls the power supply circuit unit by switching to the first or second heating mode based on the time measured by the timer. vessel. The direction switching means has an electric energy measuring means for measuring electric energy,
The control circuit unit controls the power supply circuit unit by switching to the first or second heating mode based on the electric energy measured by the electric energy measuring unit. Induction heating cooker. The direction switching unit includes a heating mode setting unit that can set the first or second heating mode by a user,
The induction heating cooker according to claim 1, wherein the control circuit unit controls the power supply circuit unit by switching to the first or second heating mode set by the heating mode setting means. The direction switching means includes a menu selection means that allows a user to select a desired dish from a menu including a plurality of dishes,
The control circuit unit controls the power supply circuit unit by switching to the first or second heating mode according to a predetermined heating program corresponding to a desired dish selected by the menu selection unit. The induction heating cooker according to claim 1. The direction switching means has automatic cooking means that can arbitrarily set a heating program by the user,
2. The induction heating according to claim 1, wherein the control circuit unit controls the power supply circuit unit by switching to the first or second heating mode according to a heating program set by the automatic cooking unit. Cooking device. At least two or more heating coils of the central heating coil and the plurality of peripheral heating coils are connected in series or in parallel,
The induction heating cooker according to claim 1, wherein the single power supply circuit unit supplies a high-frequency current to the at least two heating coils.

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