JP2011048960A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a user to continue cooking by eliminating malfunction of stopping a circuit or of reducing a high-frequency current due to fluctuations of electrostatic capacitance possible in usual cooking. <P>SOLUTION: When an increased amount of electrostatic capacitance exceeds a first increased amount, a boil-over determining part reduces a heating output and makes a timing part start time-lapse measurement, and when the time-lapse when the increased amount returns to a second increased amount set at the first increased amount or less is less than a prescribed time, a signal to return the heating output to the output before reduction is output to a control part, while, when the time-lapse is more than the prescribed time, by outputting the signal to carry out transition to a boil-over control mode, since boil-over can be confirmed without being affected by fluctuations in the electrostatic capacitance possible in usual cooking, incorrect operation of boil-over detection can be prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an induction heating cooker, and more particularly to an induction heating cooker that can avoid erroneous detection of overflow due to a capacitance change that may occur during normal cooking.

  Conventionally, this type of induction heating cooker has a configuration in which when the capacitance increases above a predetermined value, it is determined that the spill is over and the circuit is stopped or the high-frequency current flowing through the coil is reduced (for example, , See Patent Document 1).

JP 2008-159494 A

  However, in the above-described conventional configuration, in all cases where the capacitance increases above a predetermined value, it is determined that the spillage has occurred. Therefore, the capacitance variation that may occur during normal cooking, for example, when a cloth is touched, When touching, or when the pot is stirred with a metal candy, etc., even if the capacitance increases when it is not spilled, the circuit is stopped or the high-frequency current is reduced, so it can be used even during normal cooking It was impossible for the person to continue cooking.

  The present invention solves the above-mentioned conventional problems, and an induction heating cooker that avoids erroneous detection of overflowing without stopping the circuit or reducing high-frequency current due to capacitance fluctuation that may occur during normal cooking. The purpose is to provide.

  In order to solve the above-described conventional problems, an induction heating cooker according to the present invention includes a capacitance detection unit that detects an increase in capacitance relative to capacitance when there is no spill, and a capacitance detection unit. Based on the detection result, when it is detected that a spill has occurred, a spill detection unit that outputs a spill detection signal to the control unit, a storage unit that stores a preset time, a timing unit that measures elapsed time, and heating When controlling the output and inputting a spill detection signal from the spill determining unit, the control unit decreases the heating output, and the spill determining unit has a capacitance increase amount exceeding the first increase amount. When the heating output is reduced and the elapsed time is started to be measured by the time measuring unit, the increase in the capacitance returns to the second increase set to be equal to or less than the first increase thereafter. If the time is less than the predetermined time, it is determined that no spill has occurred, and a signal for returning to the output before reducing the heating output is output to the control unit, and when the elapsed time is equal to or longer than the predetermined time, It is determined that the overflow has occurred, and a signal for shifting to the overflow control mode, which is a control mode corresponding to the overflow, is output to the control unit.

  As a result, capacitance fluctuations that can occur during normal cooking, such as when a cloth is touched, touched by hands, or when a pan is stirred with a metal candy, etc. Thus, it is possible to discriminate from the change in the capacitance due to the spillage, so that it is possible to prevent the malfunction of the detection of spilling due to the capacitance variation during cooking.

  The induction heating cooker according to the present invention measures the capacitance fluctuation for a predetermined time, eliminates the malfunction of the overflow detection, can continue cooking, and can improve convenience.

The block diagram of the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the position of the electrode of the induction heating cooking appliance in Embodiment 1 of this invention The graph which shows the increase amount of the electrostatic capacitance at the time of the spilling of the induction heating cooking appliance in Embodiment 1 of this invention Flowchart until determination of boiling over of induction heating cooker in Embodiment 1 of the present invention The block diagram of the induction heating cooking appliance in Embodiment 2 of this invention External view of the operation part and display part of the induction heating cooking appliance in Embodiment 3 of this invention Graph of power consumption with respect to increase in capacitance of electrode in embodiment 4 of the present invention

  1st invention is an induction heating cooking appliance, the top plate which installs a pan, the induction heating coil which is provided under a top plate, and heats a pan, is provided in the lower part of a top plate, seeing from the upper part, An electrode made of a conductor disposed near the outer periphery of the induction heating coil and a high-frequency signal applied to the electrode to detect the increase in capacitance relative to the capacitance of the electrode when there is no liquid spillage generated near the electrode A capacitance detection unit, a overflow determination unit that outputs a overflow detection signal to the control unit when it detects that a overflow has occurred based on the detection result of the capacitance detection unit, and a memory that stores a preset predetermined time Control unit, a time measuring unit for measuring elapsed time, and the heating output, and when a spill detection signal is input from the spill determining unit, the heating output is reduced. A control unit that causes the spillage determination unit to reduce the heating output and start the elapsed time measurement when the increase exceeds the first increase, and then the increase is less than or equal to the first increase. If the elapsed time when returning to the second increase amount set to is less than the predetermined time, it is determined that no spillage has occurred, and a signal for returning the heating output to the previous output is sent to the control unit. When the elapsed time is equal to or longer than the predetermined time, it is determined that a spill has occurred, and a signal for shifting to the spill control mode, which is a control mode corresponding to the spill, is output to the control unit, so that during normal cooking Since spillage can be confirmed without being affected by potential capacitance fluctuations, malfunctions of spillover detection can be prevented. Can be enhanced can be convenient.

  In particular, the second invention includes a heating output display unit that displays the set heating output in the induction heating cooker of the first invention, and the heating output display unit has an increase in capacitance of the first. Even if the amount exceeds the increase amount, the heating output immediately before being reduced is displayed, and when the spillage determination unit determines that the spillage has occurred and then displays the reduced heating output, the user is not spilled. Can continue cooking without a sense of incongruity.

  In particular, the third aspect of the present invention is the induction heating cooker of the second aspect of the present invention, further comprising an operation unit for the user to increase or decrease the heating output, and the control unit has an increase in capacitance of the first increase amount. If the operation unit is changed so that the heating output is reduced before it is determined that the spillover has occurred, the display on the heating output display unit is changed based on the instruction from the operation unit. By not making changes, the user's intention can be reflected in the heating power during cooking.

In particular, in the induction heating cooker of the third invention, the fourth invention is provided with a spillage presence / absence display unit for displaying that when the spillage determination unit determines that spillage has occurred. When there is an input from the user when the operation has been displayed, the user can continue cooking smoothly by stopping the display of the occurrence of spilling. I can do it.

  In a fifth aspect of the invention, in particular, in the induction heating cooker of any one of the first to fourth aspects of the invention, during the boiling-out control mode, the boiling-out determination unit outputs a signal for reducing the heating output to the control unit. In addition, the time measurement unit outputs a signal for restarting time measurement, and then the elapsed time when the capacitance increase amount returns to the second increase amount set to be equal to or less than the first increase amount, If it is less than the predetermined time, it is determined that the spillage has stopped, and a signal for returning to the output before reducing the heating output is output to the control unit, and if the elapsed time is longer than the predetermined time, the spillage continues. By outputting a signal to stop the heating output to the control unit, it is possible to change the heating output step by step, so the heating does not stop even when light spilling occurs. It is possible to continue the cooking to's.

  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 shows a configuration diagram of an induction heating cooker according to the first embodiment of the present invention.

  In FIG. 1, a pan 1 is installed on a top plate 2, an induction heating coil 3 below the top plate 2, and an electrode 4 and an electrode 4 made of a conductor disposed near the outer periphery of the induction heating coil as viewed from above. A capacitance detection unit 5 is provided for applying a high frequency signal to the electrode and detecting an increase in capacitance with respect to the capacitance of the electrode when there is no liquid spillage generated near the electrode.

  The electrostatic capacitance detection unit 5 includes an oscillator 6 for supplying a high-frequency current, a rectifier 7, a voltage detection unit 8, and a storage unit 9 for storing a predetermined voltage value set in advance.

  When the overflow detection unit 12 detects that the overflow has occurred based on the detection result of the capacitance detection unit 5, the overflow detection signal is output to the control unit 10.

  The storage unit 14 stores a predetermined time set in advance. The time measuring unit 13 measures the elapsed time for determining whether the spill is over. The control unit 10 controls the heating output, and reduces the heating output when a spillage detection signal is input from the spillage determination unit 12.

  When the increase amount of the capacitance exceeds the first increase amount, the spillage determination unit 12 decreases the heating output and causes the timing unit to start measuring elapsed time, and thereafter, the increase amount of the capacitance is the first increase amount. When the elapsed time when returning to the second increase amount set to be less than the increase amount is less than the predetermined time, it is determined that no spilling has occurred, and a signal for returning to the output before reducing the heating output Is output to the control unit.

  If the elapsed time is equal to or longer than the predetermined time, it is determined that a spill has occurred, and a signal for shifting to the spill control mode, which is a control mode corresponding to the spill, is output to the control unit.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

First, when predetermined electric power is supplied from the control unit 10 to the induction heating coil 3, the pan 1 is heated. When heating progresses and spilling occurs from the pan 1, liquid such as water or seasoning liquid is applied to the top plate 2, and the capacitance of the electrode 4 located below the top plate 2 increases from a normal state.

  When the capacitance measured by the capacitance detection unit 5 increases, the spillage determination unit 12 outputs a signal to the control unit 10 to reduce the heating output so that the spillage does not increase, assuming that the spillage has occurred. At the same time, a signal is output to the time measuring unit 13 so as to measure the time for determining whether the spill is over.

  The storage unit 14 stores in advance the time required for the determination of the spill, for example, 3 seconds, and the spill determination unit 12 has the time measured by the time measuring unit 13 for 3 seconds or more, and the capacitance detection unit 5. When the detected increase in capacitance continues, it is determined that a spill has occurred, and a signal is output to the control unit 10 so as to shift to the spill control mode.

  When the increase amount returns to the original value within 3 seconds, it is determined that the spillage has not occurred, and a signal to the effect that the heating output is restored is output to the control unit 10. Although the predetermined time is 3 seconds, it is not limited to this.

  FIG. 2 is a diagram showing the positions of the electrodes of the induction heating cooker according to the first embodiment of the present invention, and shows the induction heating coil as viewed from above.

  In FIG. 2, the electrode is disposed in the vicinity of the outer periphery of the induction heating coil when the induction heating coil is viewed from above, but the outer periphery may be on the outer side or the inner side. By installing them on both sides or in the vicinity of the outer circumference, the entire area around the pan can be monitored, and the area where the capacitance of the electrodes can be detected increases, so when a spill occurs, a wide range of spills can be detected from a narrow range. Even when the pan is placed out of position, it is possible to detect spillage and improve the accuracy of detection.

  FIG. 3 is a graph showing an increase in capacitance when the induction heating cooker according to the first embodiment of the present invention is spilled.

  In FIG. 3, the horizontal axis represents time and the vertical axis represents the capacitance value. A solid line 15 indicates the capacitance when spilling, and a solid line 16 indicates the capacitance that occurs when the pot is touched or wiped with a cloth. In both cases, when the action is performed, the capacitance similarly increases to ΔC1 or more.

  When the increase amount is equal to or greater than a predetermined first increase amount ΔC1, the overflow determination unit outputs a signal for lowering the heating output to the control unit and a signal for starting time measurement to the time measuring unit. .

  As shown by the solid line 15, when the predetermined amount of increase ΔC2 has not been returned for a predetermined time T1 or more, the spillage determination unit determines spillage and shifts to the spill control mode.

  Further, when it is detected that the amount has returned to the second increase amount ΔC2 or less as indicated by the solid line 16, the spillage determination unit 12 determines that the capacitance change is not a spillage but a pot touch or a cloth wipe. Then, a signal is output to the control unit 10 so that the heating output is returned to the original heating power equivalent amount.

  FIG. 4 is a flowchart up to the determination of spilling of the induction heating cooker according to the first embodiment of the present invention.

In FIG. 4, in step S <b> 1, the capacitance detection unit 5 measures the increase in capacitance of the electrode 4. Next, the process proceeds to step S2. In step 2, it is determined whether or not the measured increase in capacitance is equal to or greater than a predetermined first increase.

Here, if it is greater than or equal to the predetermined increment, the process proceeds to step S3. Then, the spillage determination unit 13 decreases the output to the induction heating coil 3, the time measurement unit 13 starts measuring time, and proceeds to step S4.
If the measured increase in capacitance is smaller than the predetermined increase in step S2, the process proceeds to step S1.

  Next, if the time measured in step S4 has passed a predetermined time, the process proceeds to step S5. If the capacitance increase amount measured in step S5 is equal to or greater than the second predetermined increase amount, the process proceeds to step S6, and the spillage determination unit 12 determines that the spillage has occurred and shifts to the spill control mode.

  When the capacitance increase amount measured in step S5 is smaller than the predetermined increase amount, the process proceeds to step S1.

  As described above, in this embodiment, the overflow is detected based on the detection result of the capacitance detection unit and the detection unit of the capacitance detection unit. When the event is detected, a spill detection unit that outputs a spill detection signal to the control unit, a storage unit that stores a predetermined time set in advance, a timing unit that measures elapsed time, a heating output, and a spill determination And a controller that reduces the heating output when a spill detection signal is input from the unit, and the spill determining unit reduces the heating output and increases the timing when the increase in capacitance exceeds the first increase. When the elapsed time is less than the predetermined time after the elapsed time measurement is started and then the increase in capacitance returns to the second increase amount set to be equal to or less than the first increase amount It is determined that no spill has occurred, and a signal for returning to the output before the heating output is reduced is output to the control unit.If the elapsed time is equal to or longer than the predetermined time, it is determined that the spill has occurred. By outputting to the control unit a signal that shifts to the spill control mode, which is a control mode corresponding to the above, even if an increase in capacitance that can occur during normal cooking is seen, it is distinguished from spill and stops heating The cooking can be continued without any problems.

  Although the control is performed by increasing the capacitance, the spill may be detected by the magnitude of the electrode voltage, or the spill may be detected not by the capacitance but by the voltage. The method is not limited to this.

(Embodiment 2)
FIG. 5 shows a configuration diagram of an induction heating cooker according to the second embodiment of the present invention. Description of the same parts as those in the first embodiment will be omitted, and different parts will be described.

  In FIG. 5, when the user selects a thermal power with the operation unit 17, a current for the selected thermal power is applied to the induction heating coil 3 by the control unit 11. The heating power display unit 18 displays the thermal power selected by the user through the operation unit 17.

  When the capacitance of the electrode 4 increases, the overflow determination unit 12 outputs a signal for decreasing the heating output to the control unit 10. At that time, the heating output display unit 18 (FIG. 6) displays the heating output equivalent thermal power before the capacitance decreases.

When the spillage determination unit 12 confirms the spillover and shifts to the spillover control mode, the heating output display unit 18 displays the heating power equivalent to the heating output output by the control unit 10.

  For example, the user has selected the thermal power 8 in the operation unit 17, and the setting heating output of the thermal power 8 is 2500 W. When the spilling occurs and the electrostatic capacity of the power decreases, the spillage determination unit 12 sends a signal for outputting a heating output equivalent to 500 W to the control unit 10.

  At that time, the actual output is 500 W, but the heating output display unit 18 indicates the thermal power 8. If there is no change in the capacitance even after the predetermined time, the spillage determination unit 12 determines the spillage, and the heating output display unit 18 displays the thermal power 3 of thermal power display corresponding to 500 W.

  Further, here, the heating power 8 is 2500 W, and the electric power until the spilling is confirmed is equivalent to the heating power 3 and is 500 W, but it is not limited thereto.

  When the spillage determination unit 12 determines that the spillage has occurred, the spillage presence / absence display unit 19 lights up a display indicating that the spillage has occurred and notifies the user. Examples of the display include blinking display and error display, but are not limited thereto.

(Embodiment 3)
FIG. 6 is an external view of an operation unit and a display unit of an induction heating cooker according to the third embodiment of the present invention.

  On the operation unit 17, a power source unit 23 for turning on and off the main power of the induction heating cooker, a menu selection unit 22 that allows the user to select a desired automatic course, and the user reduces the heating output. A thermal power down operation unit 20 and a thermal power up operation unit 21 to be increased are arranged.

  On the display unit 24, a heating output display unit 18 that displays the heating output based on the information from the overflow determination unit 12 is installed.

  In FIG. 6, the heating output display unit 18 has a structure in which, for example, when the heating output is a thermal power of 5, five lights are turned on from the left. In addition, it may be expressed directly as a thermal power 5 and a number, and the display method is not limited to this.

  The heating output is reduced by the user at the heating power down operation button 20 on the operation unit 17 from when the increase in capacitance exceeds the first increase until the spillover determination unit 12 determines that the spillage has occurred. When changed in this way, the overflow determination unit 12 changes the heating output display unit 18 displayed on the heating output display unit 18 in the decreasing direction based on an instruction from the operation unit 17.

  At that time, only the display is linked and the thermal power setting is not changed. Thereby, a user's intention can be reflected in the heating power during cooking.

  For example, the user has selected the thermal power 8 in the operation unit 17, and the setting heating output of the thermal power 8 is 2500 W. When the spilling occurs and the electrostatic capacity of the power decreases, the spillage determination unit 12 sends a signal for outputting a heating output equivalent to 500 W to the control unit 10.

  At that time, the actual output is 500 W, but the heating power display of the heating output display unit 18 indicates the heating power 8.

If there is no change in the capacitance even after the predetermined time has elapsed, the spillage determination unit determines the spillage, and the heating output display unit 18 displays the thermal power 3, which is a thermal power display corresponding to 500 W.

  However, when the user sets the thermal power with the thermal power down operation unit 20 during the time until the overflow detection unit detects the increase in capacitance and confirms the overflow, the heating output has already been reduced to 500W. Therefore, only the heating output display unit 18 is interlocked, and the heating output remains at 500 W.

  Further, here, the thermal power 8 is 2500 W, and the electric power until the spill is determined is 500 W corresponding to the thermal power 3, but it is not limited thereto.

  On the display unit 24, a spillage presence / absence display unit 19 that is lit when the spillage is confirmed is installed based on the information from the spillage determination unit 12.

  If the user inputs to the operation unit 17 while the spillage presence / absence display unit 19 is lit, the spillage presence / absence display unit is stopped.

  Thereby, in a state where the user is stopped due to spilling, the power can be turned on again by the power supply unit 23, or the user can easily reset the thermal power setting, so that cooking can be continued smoothly.

  Further, the spillage presence / absence display unit 19 may be blinking instead of being turned on, or the blinking and lighting color may be changed, or an error display, voice or sound may be notified, and the spillage presence / absence display unit 19 is displayed. The heating output display unit 18 may also be used.

(Embodiment 4)
FIG. 7 is a graph of the increase in capacitance and power consumption of the electrodes of the induction heating cooker in the fourth embodiment of the present invention.

  In FIG. 7, the horizontal axis represents time, and the vertical axis represents the capacitance value and the power consumption value. A solid line 25 indicates the amount of increase in capacitance when light spilling occurs, and a solid line 26 indicates power consumption at that time.

  When the electrostatic capacity increase amount continues to be ΔC2 or more for a predetermined time T1, the spillage is confirmed and the heating output to the induction heating coil is also reduced.

  At the same time, the spillage determination unit again outputs a signal that causes the timing unit to measure the time for determining the size of the spillage.

  When the time measured by the time measuring unit falls within a predetermined time T2, the increase in capacitance decreases to a second capacitance increase ΔC2 or less as indicated by the solid line 25. The spillage determination unit determines that the spillage has settled and outputs a signal for increasing the heating output to the control unit again. A solid line 26 represents power consumption at that time.

  When the time measured by the time measuring unit is a predetermined time T2 or more and the increase in capacitance is greater than or equal to the second increase in capacitance ΔC2 as indicated by the solid line 27, The spillage determination unit determines that the spillage does not fit even if heating is reduced, and outputs a signal for stopping the heating output to the control unit. A solid line 28 represents the power consumption at that time.

  As a result, when light spilling occurs, the user can continue cooking without performing the thermal power operation, and even when strong spilling occurs, the user can set the heating output without setting the thermal power stop at the operation unit. You can stop.

  As described above, the induction heating cooker according to the present invention can continue cooking without interrupting cooking due to a malfunction of detection of boiling over, and is therefore effective for general uses of heating cookers. is there.

DESCRIPTION OF SYMBOLS 1 Pan 2 Top plate 3 Induction heating coil 4 Electrode 5 Capacitance detection part 10 Control part 12 Overflow determination part 13 Timekeeping part 14 Storage part

Claims (5)

A top plate for installing a pan, an induction heating coil provided under the top plate for heating the pan, and provided at a lower portion of the top plate, disposed near the outer periphery of the induction heating coil as viewed from above. An electrode made of a conductive material, and a capacitance detection device that applies a high-frequency signal to the electrode and detects an increase in the capacitance relative to the capacitance of the electrode when there is no liquid spillage generated in the vicinity of the electrode And a spillage determination unit that outputs a spillage detection signal to the control unit when it detects that the spillage has occurred based on the detection result of the capacitance detection unit, and a storage unit that stores a preset predetermined time. A time measuring unit for measuring the elapsed time, and controlling the heating output, and inputting the spill detection signal from the spill determining unit, And a control unit that reduces the heating output, and when the increase amount exceeds the first increase amount, the spillover determination unit decreases the heating output and starts the elapsed time measurement in the time measuring unit, and then If the elapsed time when the increase amount returns to the second increase amount set to be equal to or less than the first increase amount is less than the predetermined time, it is determined that the spillage has not occurred, and the heating A signal for returning the output to the previous output is output to the control unit, and if the elapsed time is equal to or longer than the predetermined time, it is determined that the spill has occurred, and a control mode corresponding to the spill is performed. An induction heating cooker that outputs a signal to shift to a certain overflow control mode to the control unit. A heating output display unit that displays a set heating output is provided, and the heating output display unit displays the heating output immediately before being reduced even if the increase in capacitance exceeds the first increase. The induction heating cooker according to claim 1, wherein the spillage determination unit displays the reduced heating output after determining that spillage has occurred. A user has an operation unit for increasing / decreasing the heating output, and the control unit controls the operation unit from the time when the increase amount of the capacitance exceeds the first increase amount until the spillage determination unit determines that the spillage has occurred. The induction heating cooker according to claim 2, wherein when the heating output is changed so as to decrease, the display of the heating output display unit is changed based on an instruction from the operation unit, and the heating output is not changed. When the spillage determination unit determines that spillage has occurred, the spillage presence / absence display unit displays that fact, and the spillage presence / absence display unit is used for the operation unit when displaying that the spillage has occurred The induction heating cooker according to claim 3, wherein when there is an input by a person, the display that the spilling has occurred is stopped. During the spill control mode, the spill determination unit outputs a signal for reducing the heating output to the control unit, and outputs a signal for restarting the time measurement to the timing unit, and then the capacitance increase amount is When the elapsed time when returning to the second increase amount set to be equal to or less than the first increase amount is less than the predetermined time, it is determined that the spillage has been settled, and before the heating output is reduced. A signal to be returned to the output is output to the control unit, and when the elapsed time is equal to or longer than the predetermined time, a signal to stop the heating output is determined by determining that the spilling has continued. The induction heating cooking appliance of any one of Claims 1-4 which output.

Images