JP2008262722A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooker which has a fixed quantity calculating means that, in cooking a fried food, fixes a warp quantity of the bottom of a heated subject and a load on a pot from the result of calculation of a temporary warp quantity and a temporary load to be able to linearly calculate an actual warp quantity and an oil quantity, especially to determine a warp and a load on a pot in cooking a fried food quantitatively, and to arbitrarily set a control means in detail based on a calculation result to reduce an error in determination for control to take place after the determination. <P>SOLUTION: Based on output from a thermistor 19, a fixed quantity calculating means 34 linearly determines an actual warp and an actual load in the form of a series of calculation equations with different constants from a temporary warp quantity and a temporary load calculated by a temperature gradient calculating means 32 and a temperature difference calculating means 33. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an induction heating cooker having induction heating means used by being incorporated in a cabinet such as a kitchen.

Conventionally, in this type of induction heating cooker, as shown in FIG. 9, a top plate 41 for placing an object to be heated on the top surface of a main body 40, a heating coil 42 for induction heating the object to be heated, and the heating coil An inverter circuit 43 that supplies a high-frequency current to 42 and a temperature detection thermistor 44 in the center of the heating coil 42 are arranged to conduct heat conduction from the bottom surface of the pan 45 placed on the top plate 41 and the heat conduction. From the temperature calculation means that calculates the bottom temperature of the pan 45 according to the output from the received thermistor 44, the amount of warpage of the pan is estimated by the second-order differential value, and divided into a flat pan, a warp 1 pan, a warp 2 pan, Also, the amount of oil is estimated from the heat capacity of the pan and the temperature at the bottom of the pan using a heat transfer equation, divided into small amount oil, medium amount oil and large amount oil, and the output of the inverter circuit 43 is controlled based on those results (Example If, see Patent Document 1).
Japanese Patent Laid-Open No. 2001-351717

  However, in the above-described conventional configuration, in fried food cooking, when the warpage amount is detected near the warpage setting threshold due to the variation in warpage of the pan bottom, and when the oil amount is detected near the setting threshold, the determination time Since the boundary zone is rough, erroneous detection may occur, and if an erroneous detection occurs, the subsequent control level will shift greatly, making it difficult to finely adjust the temperature and detect the oil amount with high accuracy. For example, if a warped pan is mistakenly detected as a flat pan, the detection of the actual thermistor may not follow the control temperature of the flat pan, and the oil temperature may rise to the high temperature side. The cooking level also decreases. Also, if a small amount of oil is judged as a large amount of oil, the input power is increased for a small amount of oil and input for a long time, so there is no denying that the ignition temperature may be reached without safety means such as a protective sensor. It had the problem that.

  The present invention solves the above-described problems of the prior art, and particularly calculates the amount of change in temperature difference after elapse of a predetermined time and the current temperature difference as the amount of provisional warpage at the bottom of the pan, and after detecting the amount of provisional warpage, calculates the temperature gradient. The means is configured to calculate the temporary load amount of the pan with the temperature change amount updated every predetermined time. From the calculation result of the temporary warpage amount and the temporary load amount, the warpage amount of the bottom of the object to be heated and the inside of the pan By providing a quantitative calculation means for determining the load amount, the actual warpage amount and oil amount can be calculated linearly, and in particular, the pan warpage determination and the load amount determination in frying can be quantitatively performed. An object of the present invention is to reduce the determination error for performing control after determination by arbitrarily finely controlling the control means based on the calculation result.

  In order to solve the above-described conventional problems, a heating cooker according to the present invention includes a top plate for placing an object to be heated on a top surface of a main body, a heating coil for inductively heating the object to be heated, and a high-frequency current in the heating coil. An inverter circuit for supplying heat, an operation section for setting the heating power of the inverter circuit, a display section for displaying setting contents and conditions, a temperature detection means for detecting the temperature of the object to be heated, and an output of the temperature detection means Temperature control means for controlling the heating power amount of the object to be heated by controlling the high-frequency current of the heating coil based on the above, temperature gradient calculation means for calculating the amount of time change of the detection value of the temperature detection means, Storage means for storing a detected value, wherein the temperature gradient calculating means calculates the amount of change in temperature difference after a predetermined time has elapsed as a temporary warpage amount of the bottom of the object to be heated, and the temporary warpage amount After detection, The temperature gradient calculating means is configured to calculate the temporary load amount of the object to be heated with a temperature change amount that is updated every elapse of a predetermined time, and from the calculation results of the temporary warpage amount and the temporary load amount, In the configuration provided with quantitative calculation means for determining the amount of warp of the bottom of the object and the amount of load in the object to be heated, it is possible to quantitatively determine the warpage of the pan and the amount of load in the cooking of the deep-fried food. The error can be reduced.

  The heating cooker according to the present invention obtains a temporary warpage amount and a temporary load amount from the result detected by the temperature detection means, particularly in deep-fried food cooking, and calculates an actual estimated warpage amount and load amount from a preset quantitative calculation means. The error of the determination result can be reduced by using the range of the calculation result, and the thermal power control can be appropriately performed. In addition, by limiting the results of the amount of temporary warpage and the amount of temporary load, if the amount of warpage of the pan bottom of the object to be heated is too large, or if the amount of load is extremely small, detection should be performed in advance. Can do. Further, by providing supplementary means in the quantitative calculation means, it is possible to cope with a change in conditions due to a change in the internal configuration of the housing.

  According to a first aspect of the present invention, there is provided a top plate for placing an object to be heated on a top surface of a main body, a heating coil for inductively heating the object to be heated, an inverter circuit for supplying a high-frequency current to the heating coil, An operation unit for setting thermal power, a display unit for displaying setting contents and conditions, a temperature detection unit for detecting the temperature of the object to be heated, and a high-frequency current of the heating coil are controlled based on the output of the temperature detection unit Temperature control means for controlling the heating power amount of the object to be heated, temperature gradient calculation means for calculating the amount of time change of the detection value of the temperature detection means, and storage means for storing the detection value. The temperature gradient calculating means calculates the amount of change in the temperature difference after the lapse of a predetermined time as the provisional warp amount of the bottom of the object to be heated, and after detecting the amount of temporary warp, the temperature gradient calculating means Over time In the configuration for calculating the temporary load amount of the object to be heated by the temperature change amount updated to the above, the amount of warpage of the bottom of the object to be heated and the object to be heated are calculated from the calculation result of the amount of temporary warpage and the temporary load amount. Is provided with quantitative calculation means for determining the load amount.

  Thus, from the calculation results of the amount of temporary warpage and the amount of temporary load, the actual amount of warpage and the amount of oil can be estimated using quantitative calculation means for determining the amount of warpage of the bottom of the object to be heated and the amount of load inside the pan. The warpage amount and the load amount can be calculated linearly, and by performing control based on the calculation result, the warpage determination and load amount determination of the pan can be quantitatively performed, and the determination error can be reduced.

  In the second invention, in particular, in the first invention, the cooking condition is set to the fried food mode.

  In this way, especially when the temperature detection means is not accurately performed due to misdetection of the amount of warpage or oil amount of the pan, the determination of the warpage of the pan and the load amount determination in frying food cooking that can not deny the risk of oil ignition Since the determination error can be reduced, the safety can be improved.

  In the third aspect of the invention, particularly in the first or second aspect of the invention, a restriction is provided on the change amount of the temperature difference after a predetermined time has elapsed.

  As a result, when using a pan for which the amount of warpage of the pan is difficult to calculate accurately, if the amount of change in temperature difference is small relative to the threshold value, it is regarded as a non-conforming pan for use regardless of the quantitative calculation means. Safety can be improved by limiting.

  According to a fourth aspect of the present invention, in particular, in any one of the first to third aspects, the temperature change amount updated every predetermined time is limited.

  As a result, when a small amount of oil that is difficult to accurately calculate the oil amount is used, a small amount of oil is not used regardless of the quantitative calculation means when the amount of temperature change updated every predetermined time is larger than the threshold value. Safety and cooking performance can be maintained by causing the control to be performed at a lower set control temperature, assuming that it is being used.

  According to a fifth invention, in any one of the first to fourth inventions, the quantitative calculation means is provided with a correction means.

  Thereby, even when the condition changes due to a change in the internal configuration of the housing, it is efficient because it can be dealt with only by correcting the coefficient of the quantitative calculation means.

  In a sixth aspect of the invention, particularly in any one of the first to fourth aspects of the invention, the value obtained from the quantitative calculation means is displayed on the display unit.

  Thereby, since the user can recognize visually the curvature amount and load amount (oil amount) of the pot currently used, it can cook more safely and correctly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIGS. 1-8 shows the top view of the heating cooker in the 1st Embodiment of this invention.

  In FIG. 1, the cooker main body 1 is dropped into the work top 2 of the kitchen cabinet and incorporated. The upper surface of the main body 1 is covered with a plate frame 4 surrounding the top plate 3 made of crystallized glass. In addition, as shown in FIG. 1, the top plate 3 includes induction heating portions 5 a and 5 b and electric resistance heating type heating means 6 (hereinafter referred to as a “radiant heater portion 6”) to constitute the top plate 3. Inductive heating operation sections 7 and 8 and a radial operation section 9 corresponding to the induction heating sections 5a and 5b and the radial heater section 6 are arranged in the front part of the member. The operation units 7, 8, and 9 are capacitance detection type touch keys that react to changes in the electric capacity by touching the electrode part printed on the top plate 3, and the top surface has no irregularities, so that it can be maintained. The flat contact type is easy to handle. Note that the operation unit of the present embodiment is not limited to the capacitance detection type, and the same effect can be obtained with a push button type operation unit such as a tact type. The central heating means is not limited to the radiant heater section 6 and may be induction heating type heating means. Also, on the side surface of the main body 1, there are disposed a grill portion 10 disposed inside the left side of the main body 1 and a grill operation portion 11 capable of storing a tact switch for operating the grill portion 10. In addition, the operation part of the radial heater part 6 distribute | arranged to a top | upper surface center part shall not be limited to the operation part 9, but may be put together in the grill operation part 11.

  Inside the main body corresponding to the induction heating parts 5a and 5b and the radial heater part 6, a heating coil constituting the induction heating means and a radial heater which is an electric resistance heating type heating means are arranged behind the heating coil. . An energization control circuit (not shown), which is a power supply circuit for the heating coil, is arranged below the heating coil, and a cooling fan (not shown) is provided at a position below the operation circuit unit in front of the circuit unit (not shown). ) And an intake port (not shown) is provided in the depth of the main body 1 below.

  In addition, as shown in FIG. 2, the operation unit corresponding to the induction heating units 5a and 5b includes, for example, a heating on / off key 7a for energizing the left heating unit, a fried food key 7e for fried food cooking, A heating power up key 7b and a heating power down key 7c for adjusting the heating power of the heating unit, a timer time setting key for setting cooking time, an auto cooking key, and the like are arranged. The display unit 7d displays an input state, a timer time, a set heating power, a set temperature, and the like by an LCD or LED. Similarly, the operation keys are arranged in the right induction heating and radial heater section and the grill operation section. The notification means comprises a speaker, an amplifier and sound information that can notify a user of a buzzer or sound for notifying the user of the state of the cooking device. Moreover, the control means of the heating cooker in this Embodiment is implement | achieved using a microcomputer.

  As shown in FIG. 3, the temperature detection means includes a thermistor 19 in the vicinity of the center of the heating coil 16, and the thermistor 19 detects the temperature of heat transfer through the top plate 3 from the tempura pan 18 that is the object to be heated. Further, the thermistor 19 is disposed in the vicinity of the center of the heating coil 16 in order to make it less susceptible to the influence of the magnetic flux from the heating coil 16.

  The detection operation will be described from the control block diagram shown in FIG. The commercial power supply 25 is input to the rectifying / smoothing unit 26. The rectifying / smoothing unit 26 is connected to a full-wave rectifier formed of a bridge diode and a low-pass filter formed of a choke coil and a smoothing capacitor between its DC output terminals. An inverter circuit 23 is connected to the output of the rectifying / smoothing unit 26, and the heating coil 16 is connected to the inverter circuit 23. The inverter circuit 23 and the heating coil 16 constitute a high frequency inverter. The inverter circuit 23 is provided with a switching element 27 (IGBT in the present embodiment). A diode 28 is connected to the switching element 27 in antiparallel. A resonance capacitor 29 is connected in parallel to the heating coil 16. The inverter circuit 23 controls the current flowing through the heating coil 16 by controlling the energization rate of the switching element 27 in accordance with a signal from the output control means 30, and the heating power for heating the object to be heated 18 (hereinafter referred to as the tempura pan 18). Control the strength of the. The detection value of the thermistor 19 is transmitted to the temperature control means 31. The temperature control means 31 detects heat transfer from the tempura pan 18 and controls the high frequency current of the heating coil 16 based on the output of the thermistor 19 to control the heating power amount of the tempura pan 18. Further, the temperature control means 31 compares the detection value of the thermistor 19 with the control temperature stored in the storage circuit 35, and transmits a signal to lower or stop the output to the output control means 30 if the detection value exceeds the control temperature. The temperature difference calculation means 33 calculates the temperature difference (for example, the difference between the temperature 60 seconds ago and the current temperature) of the detected value of the temperature detection means (not shown). The temperature gradient calculation unit 32 calculates a temperature gradient for each predetermined time of the detection value of the temperature detection unit. The quantitative calculation means 34 is determined from the calculation results of the temperature difference calculation means 33 and the temperature gradient calculation means 32 and transmits it to the output control means 30. The output control means 30 controls the energization rate of the switching element 27 to determine the tempura pan 18. Heat with heat. Usually, the thermal power is determined to be smaller as the calculation result of the temperature difference calculation means 33 is smaller and the calculation result of the temperature gradient calculation means 32 is larger.

  Next, the operation and action of the quantitative calculation means 34 will be described with reference to FIGS.

  FIG. 5 is a diagram showing a change amount of the temperature difference calculated from the detection value of the temperature detection means (here, assumed as a temporary warping amount ΔTS) when oil is put in the tempura pan 18 and heated at a constant input power for an arbitrary time. is there. FIG. 6 shows a temperature difference calculated from the detection value of the temperature detection means when heated at a constant input power for an arbitrary time based on the level of warpage calculated in FIG. 5 (here, it is assumed as a temporary load amount ΔQ). FIG. In FIG. 5, the amount of change in temperature difference when a constant input power is input for several tens of seconds (for example, about 30 to 40 seconds), that is, temperature difference ΔTS1 after elapse of a predetermined time after starting heating and temperature difference after elapse of time. A difference ΔTS = ΔTS2−ΔTS1 of ΔTS2 is set as a temporary warp amount of the tempura pan. Next, as shown in FIG. 7, quantitative calculation means set in advance based on basic data obtained from various actual warp pans for the above-described ΔTS pan warp amount, for example, the actual warp amount as S1 or S2, S1 = sb1−sa1 × ΔT (sa1 and sb1 are constants based on the basic data described above), and the range of the provisional warpage amount as a continuous calculation formula having different constants as in S2 and S3 according to the tendency of the basic data. It is assumed that various types of switching are performed according to the above, and an approximate expression for calculating the amount of warpage obtained from various amounts of actual warpage. Next, as shown in FIG. 6, after the warp amount is determined, a temperature difference (for example, input until the thermistor temperature reaches 120 ° C.) is input until a constant input power is input until the thermistor 19 reaches a predetermined temperature Tp (for example, input). , 60 seconds temperature difference) is a temporary load amount (hereinafter, the load amount is referred to as oil amount) ΔTQ. Next, as shown in FIG. 8, quantitative calculation means set in advance based on the basic data obtained from the actual various oil amounts with respect to the temporary oil amount of ΔTQ described above, for example, Q1 = Q1 = Q1 = Q2 qb1−qa1 × ΔTQ (qa1, qb1 are constants based on basic data), and are switched according to the range of the temporary oil amount as a continuous calculation formula with different constants such as Q2 and Q3 according to the trend of the basic data It is an approximate expression for calculating the oil amount obtained from various actual oil amounts.

  The operation and action of the induction heating cooker configured as described above will be described below with reference to FIGS.

  First, as shown in FIG. 3, heating of the tempura pan 18 on the heating cooker is started by the fried food key 7e of the operation unit 11 of FIG. When heating is started, the inverter circuit 23 supplies a high-frequency current to the heating coil 16, and the tempura pan 18 self-heats from the magnetic flux from the heating coil 16. Heat generated from the tempura pan 18 is detected by the thermistor 19, and the temperature control is performed through the operation described above with reference to FIG. The temperature detection means (not shown) determines the amount of warpage and the amount of oil through the operations described above with reference to FIGS.

  As described above, in the present embodiment, from the calculation results for estimating the amount of temporary warpage and the amount of temporary oil, the amount of warpage at the bottom of the object to be heated and the amount of oil in the pan are determined using the quantitative calculation means. The amount of warpage and the amount of oil can be calculated linearly, for example, the amount of warpage S = 0.25 mm, the amount of oil Q = 765 g, and the warpage determination and oil amount determination of the pan can be obtained quantitatively. In addition, the control error can be reduced by performing fine control based on the calculation result after the determination.

  Further, when a limit is set for the amount of change in the current temperature difference after the lapse of a predetermined time for obtaining the amount of provisional warpage, calculation is performed by quantitative calculation means (for example, a limit is set so that ΔTS ≦ 25). It is determined that the pan is too large or the pan is not suitable for use, and the pan is difficult to detect by the thermistor 19 by restricting the operation such as stopping the heating, and control is performed so that the oil is not heated to the ignition level. Can increase safety.

  In addition, when a limit is set for the temperature change amount that is updated every predetermined time, the oil amount is accurately determined before calculation by the quantitative calculation means (for example, a limit is set so that ΔTQ ≧ 700). When a small amount of oil that is difficult to calculate is used, a small amount of oil is used regardless of the quantitative calculation means when a temperature change amount that is updated every predetermined time is detected to be larger than the threshold value. Therefore, safety and cooking performance can be maintained by performing control to lower the set control temperature.

  In addition, when the quantitative calculation means is provided with a correction means, even if the internal cooling configuration changes due to a change in the internal configuration of the housing, etc., it is possible to cope with it simply by correcting the coefficient of the quantitative calculation means. Efficient.

  In addition, when the value obtained from the quantitative calculation means is displayed on the display unit, the user can visually recognize the warping amount and oil amount of the pan being used, so that cooking is safer and more accurate. be able to.

  As described above, the induction heating cooker according to the present invention can control the temperature adjustment by reducing the determination error of the amount of warpage and the amount of oil especially during cooking of deep-fried food and has a large amount of warpage. Appropriate control can be performed even when using a very small amount of oil, and safety and usability can be improved, so a built-in heating cooker that controls the temperature by induction heating of the load, etc. Applicable to.

The top view of the heating cooker in Embodiment 1 of this invention The elements on larger scale of the heating cooker in Embodiment 1 of this invention Configuration schematic diagram of heating cooker in Embodiment 1 of the present invention Control block diagram of heating cooker in Embodiment 1 of the present invention The figure which shows the detection value of the temporary curvature amount detection means of the heating cooker in Embodiment 1 of this invention, and the time change of a thermistor (1). The figure (2) which shows the detection value of the temporary oil amount detection means of the heating cooker in Embodiment 1 of this invention, and the time change of a thermistor. The figure which shows the change of the temporary curvature amount detection value of the heating cooker in Embodiment 1 of this invention, and the calculation value of a fixed_quantity | calculation means. The figure which shows the change of the temporary oil amount detection value of the cooking-by-heating machine in Embodiment 1 of this invention, and the calculation value of a fixed-quantity calculation means. Configuration diagram of heating cooker in the conventional example

Explanation of symbols

1, 15 Body 3 Top plate 16 Heating coil 18 Tempura pan (to be heated)
19 Thermistor (temperature detection means)
23 inverter circuit 31 temperature control means 32 temperature gradient calculation means 33 temperature difference calculation means 34 quantitative calculation means 35 storage means

Claims (6)

A top plate for placing the object to be heated on the top surface of the main body, a heating coil for induction heating the object to be heated, an inverter circuit for supplying a high-frequency current to the heating coil, and an operation unit for setting the heating power of the inverter circuit A display unit for displaying setting contents and conditions, temperature detecting means for detecting the temperature of the object to be heated, and high-frequency current of the heating coil based on the output of the temperature detecting means to control the object to be heated Temperature control means for controlling the amount of heating electric power, temperature gradient calculation means for calculating the time change amount of the detection value of the temperature detection means, and storage means for storing the detection value, the temperature gradient calculation means Calculates the amount of change in temperature difference after the lapse of a predetermined time as the amount of provisional warpage of the bottom of the object to be heated, and after detecting the amount of provisional warpage, the temperature gradient calculating means is updated every time a predetermined time has elapsed. Ru In the configuration in which the degree of change is calculated as the temporary load amount of the object to be heated, the amount of warpage of the bottom of the object to be heated and the amount of load in the object to be heated are calculated from the calculation result of the amount of temporary warp and the amount of temporary load. An induction heating cooker provided with a quantitative calculation means for determining. The induction heating cooker according to claim 1, wherein the cooking condition is a fried food mode. The induction heating cooker according to claim 1 or 2, wherein a restriction is provided on a change amount of a temperature difference after a predetermined time has elapsed. The induction heating cooker of any one of Claims 1-3 which provided the restriction | limiting in the amount of temperature changes updated every predetermined time progress. The induction heating cooker according to any one of claims 1 to 4, wherein a correction means is provided in the quantitative calculation means. The induction heating cooker according to any one of claims 1 to 5, wherein a value obtained from the quantitative calculation means is displayed on the display unit.

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