JP2008077841A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating cooker in which sufficient fire power can be obtained and heating to an abnormal high temperature can be prevented. <P>SOLUTION: The heating cooker is equipped with a memory circuit in which a first control temperature corresponding to an inverter circuit fire power set by an operating part is memorized, a first temperature control means of controlling to stop or make small output of the inverter circuit when a detected value of a temperature detecting means exceeds the first control temperature and to make the output of the inverter large when the temperature detected by the temperature detecting means reaches the first control temperature or less, a temperature difference calculating means of calculating the temperature difference between the detected value of the temperature detecting means and a target temperature renewed at every prescribed time, a temperature gradient calculating means of calculating a time change amount of the detected value of the temperature detecting means, a second temperature control means using a fire power determining means to determine the fire power of the inverter circuit by making a calculated value of the temperature difference calculating means and the temperature gradient calculating means as the input, and a loading amount discriminating means. When it is discriminated that there is a load, the fire power is controlled only by the first temperature control means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooking device used in a kitchen or the like.

  Conventionally, this type of cooking device stores the control temperature according to the output of the inverter in the memory circuit, and increases and decreases the set output every time the temperature of the thermistor reaches the control temperature according to the set output. Control temperature was also changed according to the output (for example, refer to patent documents 1).

FIG. 4 shows a conventional cooking device described in Patent Document 1. As shown in FIG. 4, an inverter 20 that converts commercial power into a high-frequency current, a control circuit 21 that controls the output of the inverter 20, a temperature detector 23 that detects the temperature of a frying pan 22 that is to be heated, and an inverter 20 is provided with an operation unit 24 for setting the output of 20, a storage circuit 25 for storing a control temperature corresponding to the output set by the operation unit 24, and a temperature control means 26 for controlling the output of the inverter 20. The means 26 stops or reduces the output of the inverter 20 when the temperature detected by the temperature detection means 23 exceeds the control temperature stored in the storage circuit 25, and the temperature detected by the temperature detection means 23 is the storage circuit 25. The temperature of the frying pan 22 is prevented from becoming an abnormally high temperature by controlling the output of the inverter 20 to be increased when the temperature is lower than the control temperature stored in the above. It is.
JP-A-9-7752

  However, in the conventional configuration described in Patent Document 1, since the temperature detection means 23 detects the temperature of the frying pan 22 via the heated object mounting table 27, the thermal response is slow and appropriate control is difficult. It was. Specifically, when the number of objects to be heated is very small, the temperature detection means stores the data in the storage circuit 25 because the temperature rise of the object to be heated is very fast while the thermal response of the temperature detection means is slow. When the control temperature is reached, the object to be heated becomes hot and may cause smoke.

  This invention solves the said conventional subject, and it aims at providing the heating cooker from which sufficient thermal power is obtained, suppressing the highest temperature of a to-be-heated material appropriately irrespective of the thermal power.

  In order to solve the above-described conventional problems, a heating cooker according to the present invention includes an inverter that converts a commercial power source into a high-frequency current, temperature detection means that detects the temperature of an object to be heated, and an operation that sets the heating power of the inverter. , A storage circuit storing a first control temperature corresponding to the heating power set by the operation unit, and a detection value of the temperature detection means exceeds a first control temperature stored by the storage circuit In such a case, the output of the inverter circuit is stopped or reduced, and the output of the inverter is increased when the temperature detected by the temperature detection means becomes equal to or lower than the first control temperature stored in the storage circuit. A first temperature control means for controlling, a temperature difference calculating means for calculating a temperature difference between a detected value of the temperature detecting means and a target temperature updated every predetermined time, and a time change of the detected value of the temperature detecting means amount A temperature gradient calculating means for calculating, a second temperature control means using a thermal power determining means for determining the thermal power of the inverter circuit with the calculated values of the temperature difference calculating means and the temperature gradient calculating means as inputs, and a load amount determining means When the load amount is determined to be large, the heating power is controlled only by the first temperature control means.

  As a result, when the load of food or the like is small, the thermal power determination means based on the calculated values of the temperature difference calculation means and the temperature gradient calculation means before the detection value of the temperature detection means reaches the control temperature stored in the storage circuit. In order to control the thermal power, the temperature of the object to be heated can be prevented from rising abnormally, and when the load is large, the thermal power set up until the temperature detection means reaches the control temperature stored in the memory circuit. Heating can be continued and the object to be heated can be sufficiently heated.

  The cooking device according to the present invention can provide a cooking device having a sufficient cooking power and good cooking performance in a normal amount of food while appropriately suppressing the maximum temperature of the pan when cooking a small amount of food. .

  1st invention respond | corresponds to the inverter which converts the commercial power source into a high frequency current, the temperature detection means which detects the temperature of a to-be-heated object, the operation part which sets the thermal power of the said inverter, and the thermal power set by the said operation part A storage circuit that stores the first control temperature, and when the temperature detected by the temperature detection means exceeds the first control temperature stored in the storage circuit, the output of the inverter is stopped or reduced. First temperature control means for controlling the output of the inverter to be increased when the temperature detected by the temperature detection means falls below a first control temperature stored in the storage circuit; and the temperature detection A temperature difference calculating means for calculating a temperature difference between a detected value of the means and a target temperature updated every predetermined time; a temperature gradient calculating means for calculating a time change amount of the detected value of the temperature detecting means; and the temperature difference A second temperature control means using a thermal power determining means for determining the thermal power of the inverter by using the calculated values of the output means and the temperature gradient calculating means as input, and a load amount determining means; The heating power is controlled only by the first temperature control means.

  Therefore, when the load of food or the like is small, the thermal power determination means uses the thermal power determination means based on the calculated values of the temperature difference calculation means and the temperature gradient calculation means before the detection value of the temperature detection means reaches the control temperature stored in the storage circuit. The temperature of the object to be heated can be prevented from rising abnormally in order to control the temperature, and when there is a large load, heating is performed with the set thermal power until the temperature detection means reaches the control temperature stored in the memory circuit. Can be continued and the object to be heated can be sufficiently heated.

  According to a second aspect of the present invention, the load amount discriminating means discriminates that the load amount is large when the integrated value of the thermal power integrating means exceeds a predetermined value, and the thermal power integrating means for integrating the thermal power determined by the thermal power determining means for a predetermined time. It is configured to do.

  Accordingly, the heating power required to control the object to be heated to a predetermined temperature is proportional to the load amount, and the load amount can be accurately determined by obtaining the integral value of the heating power for a predetermined time.

  According to a third aspect of the present invention, for each set thermal power, temperature control by only the first temperature control means, temperature control by the combined use of the first temperature control means and the second temperature control means, and only the second temperature control means. Any one of the temperature control by means of is configured to operate.

  Therefore, it is possible to prevent overheating of the object to be heated while obtaining the desired thermal power for each thermal power setting.

  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)
FIG. 1 is a block diagram of a heating cooker according to the first embodiment of the present invention.

  In FIG. 1, a commercial power source 1 is input to a rectifying / smoothing unit 2. The rectifying / smoothing unit 2 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 3 is connected to the output of the rectifying and smoothing unit 2, and an induction heating coil 4 is connected to the inverter circuit 3. The inverter circuit 3 and the induction heating coil 4 constitute a high frequency inverter. The inverter circuit 3 is provided with a switching element 5 (IGBT in the present embodiment). A diode 6 is connected to the switching element 5 in antiparallel. A resonance capacitor 7 is connected in parallel to the induction heating coil 4. The inverter circuit 4 controls the current flowing through the induction heating coil 4 by controlling the energization rate of the switching element 5 according to the signal from the output control means 8, thereby controlling the strength of the heating power for heating the object to be heated 10. The temperature detecting means 9 constituted by a thermistor or the like detects the temperature of the bottom of the article to be heated 10 via the plate 11. The detection value of the temperature detection means 9 is transmitted to the first temperature control means 12 and the second temperature control means 13. The first temperature control means 12 compares the detection value of the temperature detection means 9 with the control temperature stored in the storage circuit 14, and if the detection value exceeds the first control temperature, the output control means 8 lowers the output or stops the output. To communicate. The target temperature setting means 15 in the second temperature control means 13 sets a value obtained by adding a predetermined temperature to the detection value of the temperature detection means 9 at that time every first predetermined time as a target temperature. The maximum value of the target temperature is the second control temperature. The temperature difference calculation means 16 calculates the temperature difference between the target temperature and the detected value of the temperature detection means 9. The temperature gradient calculating unit 17 calculates a temperature gradient for each second predetermined time of the detection value of the temperature detecting unit 9. The thermal power determining means 17 determines the thermal power from the calculation results of the temperature difference calculating means 16 and the temperature gradient calculating means 17 and transmits the thermal power to the output control means 8, and the output control means 8 controls the power supply rate of the switching element 5. The heated object 10 is heated with the determined heating power. Usually, the thermal power is determined to be smaller as the calculation result of the temperature difference calculation means 16 is smaller and the calculation result of the temperature gradient calculation means 17 is larger. The load amount discriminating means 19 calculates the integrated value of the third predetermined time as needed from the output of the thermal power determining means 18, and discriminates that the load amount is large when the integrated value exceeds the predetermined value. When it is determined that the load amount is large, the load amount determination unit 19 transmits a control stop to the second temperature control unit. In this case, the temperature of the object to be heated is controlled only by the first temperature control means. The output set by the user through the operation unit 20 is transmitted to the first temperature control means 12 and the second temperature control means 13, and when the set output is low, the output is controlled only by the first temperature control means. If the temperature is high, the first temperature control means 12 and the second temperature control means 13 are used together, and only the second temperature control means is used at the maximum heating power, and the temperature control means to be used is selected according to the set output.

  The operation and action of the cooking device configured as described above will be described.

  FIG. 2 is a diagram showing the time change of the detected value of the temperature detecting means 9 and the heating power when a small amount of food is put into the object to be heated 10 such as a frying pan and heated. FIG. 3 is a diagram showing temporal changes in the detected value of the temperature detecting means 9 and the heating power when a large amount of food is put into the object to be heated 10 such as a frying pan and heated. In FIG. 2, the target temperature set by the target temperature setting means 15 is Tt. For each first predetermined time ta, a value obtained by adding a predetermined temperature ΔT to the detected value of the temperature detecting means 9 at that time is set. The maximum value of the target temperature Tt is the second control temperature T2.

  When heating is started, a target temperature Tt obtained by adding ΔT to the detected value of the temperature detecting means 9 is set. Tt is updated to the second control temperature every ta time. The temperature difference calculation means 16 calculates the temperature difference between Tt and the detection value of the temperature detection means 9. On the other hand, the temperature gradient calculating means 17 calculates the temperature gradient of the temperature detecting means 9 every Δt time. The thermal power determination means 18 determines the thermal power from the results of the temperature difference calculation means 16 and the temperature gradient calculation means 17 and updates the thermal power every fourth predetermined time (for example, 1 second). As the thermal power determination method of the thermal power determination means 18, fuzzy control or the like can be considered. If the food to be heated is a small amount of food, there is almost no influence on the temperature of the object to be heated 10 such as a frying pan, and the temperature of the object to be heated reaches the second control temperature T2 early and is calculated by the thermal power determining means 18. The integrated value Ps of the thermal power to be generated every third predetermined time ts is not a large value. Accordingly, the load amount determination means 19 determines that the load amount is small, and at least the temperature control by the second temperature control means 13 is continued, and overheating of the article to be heated 10 is prevented. In FIG. 3, the same control as in FIG. 2 is performed at the beginning of heating. However, when a large amount of food is introduced after the lapse of tb time, the temperature of the object to be heated 10 rapidly decreases, and the temperature detection means 9 detects it. The value also decreases. As a result, the calculated value of the temperature difference calculating means 16 becomes large and the calculated value of the temperature gradient calculating means 16 becomes small. Therefore, the thermal power determining means 18 determines a large thermal power so that the detected value of the temperature detecting means 9 approaches the target temperature. As a result, the integral value Ps of the thermal power calculated by the thermal power determining means 18 for each third predetermined time becomes a large value, and the load amount determining means 19 determines that the load amount is large, and the temperature control by the second temperature control means is performed. Stop and perform temperature control only by the first temperature control means 12. In FIG. 3, temperature control is performed only by the first temperature control means after elapse of tc time. When the detection value of the temperature detecting means 9 reaches the control temperature stored in the storage circuit for each output, the heating power is lowered. When the detection value of the temperature detection means 9 exceeds T15, the thermal power decreases from P5 to P4, and when it exceeds T14, the thermal power decreases to P3. If the detected value becomes T15 or less, the thermal power returns to P5. As described above, when the temperature is controlled by the first temperature control means, the object to be heated 10 is sufficiently heated because the detection value of the temperature detection means 9 is heated with the set thermal power until it reaches the control temperature stored in the storage circuit. .

  As described above, in the present embodiment, when the load applied to the article to be heated 10 is small, overheating is prevented by the second temperature control means, and when the load is large, the first temperature is set. It is sufficiently heated with a strong heating power only by the control means, and both safety and cooking performance can be achieved.

  As described above, the heating cooker according to the present invention can obtain sufficient thermal power while appropriately suppressing the maximum temperature of the object to be heated, so that it is used not only for home cooking appliances but also for restaurant kitchens and the like. It can also be applied to other uses such as a heating cooker, etc., or a non-cooking heater using induction heating.

The block diagram of the heating cooker in Embodiment 1 of this invention The figure which shows the detected value of the temperature detection means at the time of the small load amount in Embodiment 1 of this invention, and the time change of a thermal power. The figure which shows the detected value of the temperature detection means at the time of the large load amount in Embodiment 1 of this invention, and the time change of a thermal power Block diagram of a conventional cooking device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Commercial power supply 3 Inverter circuit 9 Temperature detection means 10 Heated object 12 1st temperature control means 13 2nd temperature control means 14 Storage circuit 16 Temperature difference calculation means 17 Temperature gradient calculation means 18 Thermal power determination means 19 Load amount determination means 20 Operation Part

Claims (3)

An inverter that converts commercial power into a high-frequency current, temperature detection means that detects the temperature of the object to be heated, an operation unit that sets the thermal power of the inverter, and a first control temperature that corresponds to the thermal power set by the operation unit And when the detected value of the temperature detection means exceeds the first control temperature stored in the storage circuit, the output of the inverter circuit is stopped or reduced and the temperature detection means First temperature control means for controlling the output of the inverter to be increased when the detected temperature is equal to or lower than the first control temperature stored in the storage circuit; and a detection value of the temperature detection means; A temperature difference calculating means for calculating a temperature difference with a target temperature updated every predetermined time; a temperature gradient calculating means for calculating a time change amount of a detection value of the temperature detecting means; and the temperature difference calculating means and the temperature A second temperature control means using a thermal power determining means for determining the thermal power of the inverter circuit by using the calculated value of the distribution calculating means as an input, and a load amount determining means; A heating cooker configured to control the thermal power only by the temperature control means. The load amount discriminating means is configured to discriminate that the load amount is large when the integrated value of the thermal power integrating means exceeds a predetermined value, and a thermal power integrating means for integrating the thermal power determined by the thermal power determining means for a predetermined time. Item 10. The heating cooker according to item 1. For each set thermal power, among the temperature control only by the first temperature control means, the temperature control by the combined use of the first temperature control means and the second temperature control means, and the temperature control only by the second temperature control means The cooking device according to claim 1, wherein one of the devices is configured to operate.