JP2012089433A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform control of increasing the heating power immediately when a pan is placed on a top plate even in the case where cooking is performed while moving the pan.SOLUTION: An induction heating cooker includes a small object detecting means 14 and an output suppressing means 15. The small object detecting means 14 has a small object detection delay function of continuing operation for a certain period of time in a state where the output is suppressed by the output suppressing means 15 without stopping an inverter circuit 4 when it is determined that a load pan 12 is not suitable for heating. Thus, cooking performance can be improved while safety maintained.

Description

  The present invention relates to an induction heating cooker that is used in general homes, restaurants, offices, and the like, and particularly has a function of stopping heating when a non-heated object that is not suitable for heating, such as a knife or knife, is detected.

  2. Description of the Related Art In recent years, induction heating cookers that inductively heat a cooking container placed on a top plate by a heating coil disposed below the top plate have become widespread. The induction heating cooker is heated when non-heated items (small items) that are not suitable for heating, such as knives and knives, are placed on the top plate, or when heated items are not placed on the top plate. It is desirable to stop.

  Therefore, the conventional induction heating cooker detects whether or not the object to be heated is placed on the top plate by detecting the degree of heating output of the inverter circuit and the input current to the inverter circuit. It is determined whether the placed object to be heated is suitable for heating (small items).

  In addition, the induction heating cooker has an inverter circuit when it is determined that the object to be heated is not placed on the top plate or that the object to be heated placed on the top plate is not suitable for heating (small item). Pause the heating output.

  This control is called an accessory detection function (or “no-load detection function” or “no pan detection function”). After the heating is temporarily stopped, after a predetermined time (for example, 2 seconds) has elapsed, the heating operation is started again, and the object to be heated is discriminated (whether it is placed on the top plate or suitable for heating).

  The operation of discriminating the object to be heated and the operation of temporarily stopping the heating are repeated for a predetermined time (for example, 1 minute) from the start of the first heating, and the heating is completely stopped after the predetermined time has elapsed. In this way, small articles such as knives and knives are prevented from being abnormally heated, and the inverter circuit is prevented from continuing to operate in a state in which an object to be heated is not placed on the top plate.

  However, in the case of cooking by shaking a pan like a fried food, the pan may temporarily leave the top plate. When the pan moves away from the top plate, the induction heating cooker determines that the object to be heated is not placed on the top plate by the accessory detection function, and temporarily stops heating.

  Thereafter, reheating is not performed until a predetermined time (for example, 2 seconds) elapses, and thus it is difficult to continue cooking while keeping the pan at a high temperature. Therefore, if it is detected that the object to be heated has been placed on the top plate and has not been placed, it is determined that cooking is in progress and the pause time is set to a predetermined time (for example, The heating power recovery at the time of reheating was accelerated by making it shorter (for example, 0.5 seconds) (for example, see Patent Document 1).

  Hereinafter, an induction heating cooker having a conventional configuration will be described with reference to FIG.

In FIG. 10, the top plate 102 mounts the load pan 101, the heating coil 103 heats the load pan 101 above the top plate 102, the control means 105 supplies a high frequency current to the heating coil 103, and the load pan 101 By controlling the output of the inverter circuit 104 for induction heating, the current supplied to the inverter circuit 104 detected by the input current detection means 106 is controlled.

  At this time, if the current detected by the input current detection means 106 does not increase even if the output of the inverter circuit 104 is increased, the heating is temporarily determined that the load pan 101 is not placed or is not suitable for heating. Stop (small item detection function).

  However, after the heating is started, when it is detected that the current detected by the input current detection means 106 has once exceeded a predetermined current value, it is determined that cooking is in progress, and the load pan 101 is shaken on the top plate 102. Even if the state is changed to a state in which it is not placed on the top plate 102, the control is performed so that the pause time is shorter than a predetermined time (for example, 2 seconds) (for example, 0.5 seconds).

  In the induction heating cooker configured as described above, after starting heating, if it is determined that cooking is in progress, even if heating is temporarily stopped by the accessory detection function, the time for temporarily stopping is shortened. Thus, it was possible to accelerate the thermal power recovery when reheating.

Japanese Patent Laid-Open No. 2-197070

  However, in the conventional configuration, heating is temporarily stopped when a state in which the object to be heated is placed on the top plate (loaded state) is changed to a state in which it is not placed (no load state). Although the heating time is shortened, the heating is not continued. For this reason, when the object to be heated is not placed on the top plate (no load state) and returned to the placed state (no load state), it cannot be immediately restored to a high heating power. It had the subject that the temperature of the to-be-heated material of a heated material fell.

  The present invention solves the above-described conventional problems, and prevents abnormal heating of small items such as knives and kitchen knives, and immediately returns to high heating power even in the case of cooking by shaking a pan like cooking fried food. An object of the present invention is to provide an induction heating cooker that can perform cooking by heating.

  In order to solve the conventional problem, an induction heating cooker according to the present invention includes a heating coil, a top plate on which a load pan is placed above the heating coil, and a high-frequency current supplied to the heating coil. Inverter circuit for heating the load pan, control means for controlling the heating output of the inverter circuit, input current detection means for detecting an input current to the inverter circuit, heating output of the inverter circuit and the input current detection means There is an accessory detection means for determining whether or not the load pan is suitable for heating based on the current detected by the output, and an output suppression means for suppressing the heating output of the inverter circuit according to the current detected by the input current detection means. And the control means does not stop the inverter circuit when the accessory detection means determines that the load pan is not suitable for heating, and outputs the output. It is obtained by a structure having a small detection delay function to continue the constant-time operation at suppressing state output by the braking means.

As a result, even if a small load such as a knife or kitchen knife is mistakenly heated, the abnormal temperature rise of the small load is prevented, and even when cooking by shaking a pan like cooking fried food Even if the load state is detected, the heating stop is delayed for a certain period of time, and the output of the inverter circuit is suppressed for a certain period of time to enter the standby state. The cooking performance can be improved while maintaining the above.

  The induction heating cooker of the present invention cooks while maintaining safety by delaying the heating stop for a certain time even when detecting the load of small items, even when cooking by shaking a pan like cooking fried food The performance can be improved, and an induction heating cooker that is more convenient for the user can be provided.

The block diagram of the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the waveform of the inverter drive signal output from the control means of the induction heating cooking appliance in Embodiment 1 of this invention. The figure which shows the accessory detection function of the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the output suppression function of the induction heating cooking appliance in Embodiment 1 of this invention The figure which shows the accessory detection delay function of the induction heating cooking appliance in Embodiment 1 of this invention. The figure which shows the waveform of the inverter drive signal output from the control means of the induction heating cooking appliance in Embodiment 2 of this invention. The figure which shows the accessory detection function of the induction heating cooking appliance in Embodiment 2 of this invention The figure which shows the output suppression function of the induction heating cooking appliance in Embodiment 2 of this invention The figure which shows the accessory detection delay function of the induction heating cooking appliance in Embodiment 2 of this invention. Block diagram of a conventional induction heating cooker

  According to a first aspect of the present invention, there is provided a heating coil, a top plate on which a load pan is placed above the heating coil, an inverter circuit that supplies a high-frequency current to the heating coil to heat the load pan, and the inverter circuit Whether the load pan is suitable for heating by the control means for controlling the heating output, the input current detecting means for detecting the input current to the inverter circuit, the heating output of the inverter circuit and the current detected by the input current detecting means An accessory detection means for judging whether or not, and an output suppression means for suppressing the heating output of the inverter circuit in accordance with the current detected by the input current detection means, the control means, the accessory detection means is the When it is determined that the load pan is not suitable for heating, the inverter circuit is not stopped and the output is suppressed by the output suppression means for a certain period of time. It is obtained by the configuration having a small detection delay function to continue the work. By this, even when cooking by shaking the pan like fried food, even if the small load state is detected, by delaying the heating stop for a certain time, when the pan is returned to the top plate again, Since the heating power can be increased immediately, the cooking performance can be improved.

  In particular, according to a second aspect of the present invention, in the first aspect of the present invention, a temperature detection unit arranged on the lower surface of the top plate for detecting the temperature of the load pan, and a temperature calculation unit for calculating the temperature of the load pan from the output of the temperature detection unit The control means is configured to enable the accessory detection delay function when the temperature calculated by the temperature calculation means is equal to or higher than a predetermined temperature. As a result, since the accessory delay function can be enabled after the temperature of the load pan becomes abnormal at the predetermined temperature, the accessory delay function is ineffective even when cooking the pan when the temperature of the load pan is low. For this reason, misuse such as cooking in a pot when the temperature of the load pan is low can be prevented.

The third invention, in particular, in the first or second invention, has a time measuring means for measuring the elapsed time since the start of heating, and the control means has a time measured by the time measuring means not less than a predetermined time. In this case, the small object detection delay function is made effective. As a result, since the accessory delay function can be enabled after the load pan has been heated for a certain time or more, the accessory delay function is disabled when the temperature of the load pan is not sufficiently increased. Misuse such as cooking in a pot when the temperature is low can be prevented.

  In particular, the fourth invention includes current integrating means for integrating the current detected by the input current detecting means after the start of heating in any one of the first to third inventions, and the control means is controlled by the current integrating means. When the integrated current amount is equal to or greater than a predetermined current amount, the accessory detection delay function is made effective. As a result, the accessory delay function can be enabled after a certain amount of heat has been applied to the load pan, so the accessory delay function is disabled when the temperature of the load pan is not sufficiently high. It is possible to prevent misuse such as cooking in a pot when the temperature of the pot is low.

  According to a fifth aspect of the invention, in particular, the inverter circuit according to any one of the first to fourth aspects includes a resonance capacitor connected to the heating coil and a switching element, and the control means sets the drive time of the switching element. The heating output of the inverter circuit is controlled by increasing / decreasing, and the accessory detection means determines whether the load pan is suitable for heating based on the driving time of the switching element and the current detected by the input current detection means, and outputs The suppression means is configured to suppress the drive time of the switching element according to the current detected by the input current detection means. As a result, the accessory detection function can be configured by the accessory detection means for determining the heating and stopping conditions of the inverter circuit and the output suppression means for performing the output suppression control of the inverter circuit, so that an accessory delay can be achieved without providing new parts and parameters. Functions can be realized. Further, even when fine adjustment of the accessory detection means and the parameter of the output suppression control is performed, the design delay can be reduced because the accessory delay function does not need to be finely adjusted.

  According to a sixth aspect of the invention, in particular, the inverter circuit according to any one of the first to fourth aspects includes a resonance capacitor connected to the heating coil and a switching element, and the control means sets the drive frequency of the switching element. The output of the inverter circuit is controlled by increasing / decreasing, and the accessory detection means determines whether the load pan is suitable for heating based on the drive frequency of the switching element and the current detected by the input current detection means, and suppresses the output. The means is configured to suppress the drive frequency of the switching element in accordance with the current detected by the input current detection means. As a result, the accessory detection function can be configured by the accessory detection means for determining the heating and stopping conditions of the inverter circuit and the output suppression means for performing the output suppression control of the inverter circuit, so that an accessory delay can be achieved without providing new parts and parameters. Functions can be realized. Further, even when fine adjustment of the accessory detection means and the parameter of the output suppression control is performed, the design delay can be reduced because the accessory delay function does not need to be finely adjusted.

  In a seventh aspect of the invention, in particular, in any one of the first to sixth aspects of the invention, the display unit is provided, and the control unit is configured to display on the display unit when the accessory detection delay function is valid. Is. Thereby, it is possible to visually tell the user whether the accessory detection delay function is in an effective state.

  In an eighth aspect of the present invention, in particular, in any one of the first to seventh aspects of the present invention, a notification unit is provided, and the control unit is configured to perform notification by the notification unit when the accessory detection delay function is valid. Is. Accordingly, it is possible to audibly tell the user whether the accessory detection delay function is in an effective state.

  According to a ninth aspect of the invention, in particular, in any one of the first to eighth aspects of the present invention, a switching unit is provided, and the control unit can switch whether or not to operate the accessory detection delay function by the switching unit. It is a thing. Thereby, since a user can select whether to enable the accessory detection delay function, usability can be further improved.

In a tenth aspect of the invention, in particular, in any one of the first to ninth aspects, the time setting unit is provided, and the control unit can change the time for operating the accessory detection delay function by the time setting unit. It is what. Thereby, since the user can select the time for operating the accessory detection delay function, the usability can be further improved.

  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 block diagram of an induction heating cooker according to the first embodiment of the present invention.

  In FIG. 1, a commercial power source 1 is full-wave rectified by a rectifier circuit 2 composed of a bridge diode and smoothed by a smoothing capacitor 3 connected between the DC connection terminals of the rectifier circuit 2, thereby It is composed.

  The output of the rectifier circuit 2 is connected to an inverter circuit 4 that converts the commercial power source 1 into a high-frequency current. The inverter circuit 4 includes a heating coil 5 and a resonance capacitor 6 connected in parallel to the heating coil. A switching element 7 (IGBT in the present embodiment) connected in series to the heating coil 5 and a reverse conducting diode 8 connected in reverse parallel to the switching element 7. Supply high frequency current.

  The input current detection means 9 detects the input current from the commercial power source 1 to the inverter circuit 4, and the control means 10 is set by the detection result detected by the input current detection means 9 and the thermal power setting means 11. The switching element 7 is controlled to be turned on / off according to the heating output setting of the inverter circuit 4.

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

  First, the commercial power source 1 is rectified by the rectifier circuit 2 and the smoothing capacitor 3 and supplies power to the inverter circuit 4. In the inverter circuit 4, the control means 10 turns on and off the switching element 7 and causes a high-frequency current to flow through the heating coil 5, so that the load pan 12 placed on the top plate 13 is induction-heated.

  The thermal power input to the load pan 12 is detected by the input current detection means 9, and the control means 10 controls on / off of the switching element 7 so as to be the thermal power set by the thermal power setting means 11.

  FIG. 2 is a diagram showing a waveform of an inverter drive signal output from the control means 10 of the induction heating cooker according to the first embodiment of the present invention. The drive frequency is around 20 kHz, and the cycle Tc is 50 μsec. The input current is controlled by changing the time Ton by setting the time Ton when the H signal is output from the control means 10 to the switching element 7 and the switching element 7 is turned on.

  For example, the time Ton is lengthened when the input current is increased, and the time Ton is shortened when the input current is decreased. The control means 10 sets the time so that the target input current is determined according to the thermal power set by the thermal power setting means 11 and the current detected by the input current detection means 9 is held at the target input current. Control Ton.

  FIG. 3 is a diagram showing the accessory detection function of the induction heating cooker in the first embodiment of the present invention, and FIG. 4 is a diagram showing the output suppression function of the induction heating cooker in the first embodiment of the present invention. is there.

  The operation of the accessory detection means 14 will be described based on the relationship between the time control amount Ton in which the switching element 7 shown in FIG. 3 conducts and the current detected by the input current detection means 9.

  Whether the accessory detection means 14 is in a state where the load pan 12 is placed on the top plate 13 (loaded state) by the time control amount Ton through which the switching element 7 conducts and the current detected by the input current detection means 9. Alternatively, it is determined whether a non-heated object that is not suitable for heating such as a knife or a knife is placed or a state where the load pan 12 is not placed (no load state).

  That is, when the control means 10 gradually increases the time control amount Ton for conducting the switching element 7, if the load pan 12 is placed on the top plate 13 (loaded state), The current detected by the input current detecting means 9 also gradually increases, but there is a state in which a non-heated object that is not suitable for heating, such as a knife or a knife, is placed or a state in which the load pan 12 is not placed (nothing Load current), the current detected by the input current detection means 9 does not increase.

  Using this relationship, the accessory detection means 14 gradually increases the time control amount Ton for turning on the switching element 7 by the control means 10, and when the time control amount Ton is a certain value, If the current detected by the detection means 9 is smaller than a certain value, it is determined that there is no load or a small load, and this is transmitted to the control means 10. At this time, the control means 10 temporarily stops the output signal to the switching element 7 (heating is temporarily stopped).

  Further, the operation of the output suppression means 15 will be described based on the relationship between the time control amount Ton in which the switching element 7 shown in FIG. 4 conducts and the current detected by the input current detection means 9. The output suppressing means 15 is configured such that the load pan 12 placed on the top plate 13 is shifted with respect to the heating coil 5 by the time control amount Ton through which the switching element 7 conducts and the current detected by the input current detecting means 9. It is determined whether it is not mounted.

  That is, when the time control amount Ton at which the switching element 7 conducts is a certain value, the load pan 12 is displaced with respect to the heating coil 5 as compared with the case where the load pan 12 is placed at the center of the heating coil 5. When it is placed, the current detected by the input current detection means 9 becomes small.

  Using this relationship, the output suppression means 15 is configured such that when the control means 10 gradually increases the time control amount Ton in which the switching element 7 is conducted, the input current If the detected current is larger than a certain value, it is determined that the load pan 12 is shifted with respect to the heating coil 5 and is transmitted to the control means 10.

  At this time, the control means 10 has a time control amount Ton that allows the switching element 7 to conduct even if the current detected by the input current detection means 9 does not reach the target current set by the heating power setting means 11. Suppression control is performed so as not to increase.

  At this time, when the load pan 12 is placed on the top plate 13 and heated, and the load pan 12 is removed from the top plate 13 after heating, the load pan 12 is not placed by the accessory detection means 14 (nothing). In other words, the function of temporarily stopping the output signal to the switching element 7 is disabled for a certain time (for example, 2 seconds) (small object detection delay function).

  While the heating stop function by the accessory detection means 14 is disabled for a certain time, the time control amount Ton in which the switching element 7 is conducted is controlled by the output suppression means 15.

  FIG. 5 is a diagram showing an accessory detection delay function of the induction heating cooker according to the first embodiment of the present invention. As shown in FIG. 5, when the load pan 12 is placed on the top plate 13 and heated, the time control amount Ton through which the switching element 7 conducts and the operating point of the current detected by the input current detecting means 9 are The small object detection means 14 does not lie in the region where it is determined that there is no load or small object load (point of the operating point 1a in FIG. 5).

  When the load pan 12 is removed from the top plate 13 in this state, it is in a no-load state. Therefore, the time control amount Ton through which the switching element 7 conducts and the operating point of the current detected by the input current detecting means 9 are small items. Although it moves to the area | region determined by the detection means 14 as a no-load state or an accessory load state (point of the operating point 2a in FIG. 5), since the heating stop function is invalidated for a fixed time, the output suppression means 15 When the output suppression control is performed, the time control amount Ton at which the switching element 7 conducts and the operating point of the current detected by the input current detection means 9 move so that the time control amount Ton at which the switching element 7 conducts becomes small ( The point of the operating point 3a in FIG. 5).

  In this state, when a certain period of time (in this example, 2 seconds) when the accessory load detection function by the accessory detection means 14 is disabled, the accessory load detection function by the accessory detection means 14 becomes valid and the switching element 7 becomes conductive. Since the operating point of the time control amount Ton to be detected and the current operating point detected by the input current detecting means 9 is within the region determined by the accessory detecting means 14 to be in the no-load state or the accessory load state, the output to the switching element 7 Pause the signal (pause heating).

  However, if the load pan 12 is placed on the top plate 13 again within a certain time period (in this example, 2 seconds) in which the accessory load detection function by the accessory detection means 14 is disabled, the switching element 7 becomes conductive. The operating point of the time control amount Ton and the current detected by the input current detecting unit 9 moves from the region where the output suppression control is performed by the output suppression unit 15 (point of the operating point 4a in FIG. 5). Increases the time control amount Ton that the switching element 7 conducts, and the operating point of the current control value Ton that the switching element 7 conducts and the current detected by the input current detection means 9 And return to the heated state (point of the operating point 1a in FIG. 5).

  In this way, by disabling the accessory detection function by the accessory detection means 14 for a certain period of time, even if the load pan 12 is removed from the top plate 13 and then immediately repositioned, the heating power can be increased immediately. Since it is possible, cooking performance can be improved.

(Embodiment 2)
The basic configuration of the present embodiment is the same as the block diagram of the first embodiment shown in FIG.

  In FIG. 1, a commercial power source 1 is rectified by a rectifier circuit 2 and a smoothing capacitor 3 and supplies power to an inverter circuit 4. The inverter circuit 4 heats the load pan 12 placed on the top plate 13 by the control means 10 turning on and off the switching element 7 and passing a high-frequency current through the heating coil 5. The thermal power input to the load pan 12 is detected by the input current detection means 9, and the control means 10 controls on / off of the switching element 7 so as to be the thermal power set by the thermal power setting means 11.

  FIG. 6 is a diagram showing a waveform of an inverter drive signal output from the control means 10 of the induction heating cooker according to the second embodiment of the present invention. The drive frequency f is controlled in the vicinity of 20 kHz to 50 kHz.

  As for the input current, an H signal is output from the control means 10 to the switching element 7, and the time for which the switching element 7 is conductive is 1 / 2f. At this time, the drive frequency f is set as a control amount, and the control means 10 is controlled by changing the drive frequency f.

  For example, when the input current is increased, the drive frequency f is decreased, and when the input current is decreased, the drive frequency is increased. The control means 10 is driven so that the target input current is determined according to the thermal power set by the thermal power setting means 11 and the current detected by the input current detection means 9 is held at the target input current. The frequency f is controlled.

  FIG. 7 is a diagram showing an accessory detection function of the induction heating cooker according to the second embodiment of the present invention.

  The operation of the accessory detection means 14 will be described based on the relationship between the control amount of the switching element 7 shown in FIG. 7, that is, the drive frequency f, and the current detected by the input current detection means 9.

  The accessory detection means 14 is in a state where the load pan 12 is placed on the top plate 13 (loaded state) by the driving frequency f of the switching element 7 and the current detected by the input current detection means 9, or It is determined whether or not a non-heated object that is not suitable for heating, such as a knife or a knife, is placed or a state where the load pan 12 is not placed (no load state).

  That is, when the control means 10 gradually decreases the driving frequency f of the switching element 7, if the load pan 12 is placed on the top plate 13 (loaded state), the input current is detected. Although the current detected by the means 9 also gradually increases, a state in which a non-heated object that is not suitable for heating such as a knife or a knife is placed or a state in which the load pan 12 is not placed (no load state) If so, the current detected by the input current detection means 9 does not increase.

  Using this relationship, the accessory detection means 14 causes the input current detection means 9 to detect when the control means 10 gradually decreases the drive frequency f of the switching element 7 and the drive frequency f is a certain value. If the detected current is smaller than a certain value, it is determined that there is no load or a small load state, and is transmitted to the control means 10.

  At this time, the control means 10 temporarily stops the output signal to the switching element 7 (heating is temporarily stopped).

  FIG. 8 is a diagram showing an output suppression function of the induction heating cooker according to the second embodiment of the present invention.

  The operation of the output suppression unit 15 will be described based on the relationship between the drive frequency f of the switching element 7 shown in FIG. 8 and the current detected by the input current detection unit 9. The output suppression means 15 is mounted so that the load pan 12 placed on the top plate 13 is shifted with respect to the heating coil 5 by the drive frequency f of the switching element 7 and the current detected by the input current detection means 9. Determine whether it is not done.

  That is, when the driving frequency f of the switching element 7 is a certain value, the load pan 12 is shifted with respect to the heating coil 5 as compared to when the load pan 12 is placed at the center of the heating coil 5. When it is mounted, the current detected by the input current detection means 9 becomes small.

Using this relationship, the output suppression means 15 is configured such that when the control means 10 gradually increases the drive frequency f of the switching element 7, the current detected by the input current is detected when the drive frequency f is a certain value. If it is larger than a certain value, it is determined that the load pan 12 is shifted with respect to the heating coil 5 and is transmitted to the control means 10.

  At this time, the control means 10 prevents the drive frequency f of the switching element 7 from further increasing even if the current detected by the input current detection means 9 does not reach the target current set by the heating power setting means 11. The output suppression control is performed.

  At this time, when the load pan 12 is placed on the top plate 13 and heated, and the load pan 12 is removed from the top plate 13 after heating, the load pan 12 is not placed by the accessory detection means 14 (nothing). In other words, the function of temporarily stopping the output signal to the switching element 7 is disabled for a certain time (for example, 2 seconds) (small object detection delay function).

  The driving frequency f of the switching element 7 is controlled by the output suppression unit 15 while the heating stop function by the accessory detection unit 14 is disabled for a certain period of time.

  FIG. 9 is a diagram showing an accessory detection delay function of the induction heating cooker according to the second embodiment of the present invention.

  As shown in FIG. 9, when the load pan 12 is placed on the top plate 13 and heated, the driving frequency f of the switching element 7 and the operating point of the current detected by the input current detecting means 9 are small object detection. It is not in the region determined by the means 14 to be in the no-load state or the accessory load state (point of the operating point 1b in FIG. 9).

  When the load pan 12 is removed from the top plate 13 in this state, it is in a no-load state. Therefore, the time control amount Ton through which the switching element 7 conducts and the operating point of the current detected by the input current detecting means 9 are small items. Although it moves to the area | region determined by the detection means 14 as a no-load state or an accessory load state (point of the operating point 2b in FIG. 9), since the heating stop function is invalidated for a fixed time, the output suppression means 15 The output suppression control is performed, and the operating frequency f of the switching element 7 and the operating point of the current detected by the input current detecting means 9 move so that the driving frequency f of the switching element 7 increases (the operating point in FIG. 9). 3b points).

  In this state, when a certain time (in this example, 2 seconds) in which the accessory load detection function by the accessory detection means 14 is disabled passes, the accessory load detection function by the accessory detection means 14 becomes effective and the switching element 7 is driven. Since the operating point of the frequency f and the current detected by the input current detection means 9 is within the region determined by the accessory detection means 14 to be in the no-load state or the accessory load state, the output signal to the switching element 7 is temporarily output. Stop (pause heating).

  However, if the load pan 12 is placed on the top plate 13 again within a certain time period (in this example, 2 seconds) in which the accessory load detection function by the accessory detection means 14 is disabled, the drive frequency of the switching element 7 Since the operating point of the current detected by f and the input current detecting means 9 moves from the region where the output suppression control is performed by the output suppression means 15 (point of the operating point 4b in FIG. 9), the control means 10 The driving frequency f of the element 7 is decreased, the time control amount Ton for which the switching element 7 is conducted, and the operating point of the current detected by the input current detecting means 9 are first heated by placing the load pan 12 on the top plate 13. It returns to the state (point of the operating point 1b in FIG. 9).

  In this way, by disabling the accessory detection function by the accessory detection means 14 for a certain period of time, even if the load pan 12 is removed from the top plate 13 and then immediately replaced, the heating power can be increased immediately. Since it is possible, cooking performance can be improved.

  As described above, the induction heating cooker according to the present invention can immediately increase the heating power not only when the load pan is stationary but also when cooking while moving. It is effective not only for heating cookers but also for induction heating cookers for business use used in restaurant kitchens.

DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Rectification circuit 3 Smoothing capacitor 4 Inverter circuit 5 Heating coil 6 Resonance capacitor 7 Switching element 8 Reverse conduction diode 9 Input current detection means 10 Control means 12 Load pan 13 Top plate 14 Small object detection means 15 Output suppression means

Claims (10)

A heating coil, a top plate on which the load pan is placed above the heating coil, an inverter circuit for supplying a high frequency current to the heating coil to heat the load pan, and a control for controlling the heating output of the inverter circuit An input current detecting means for detecting an input current to the inverter circuit; an accessory for determining whether the load pan is suitable for heating based on the heating output of the inverter circuit and the current detected by the input current detecting means; Detection means and output suppression means for suppressing the heating output of the inverter circuit in accordance with the current detected by the input current detection means, the control means is suitable for heating the load pan in the load pan. If it is determined that there is no output, the inverter circuit is not stopped and the operation is continued for a certain period of time while the output is suppressed by the output suppression means. Configuration and the induction heating cooker having a small detection delay function. A temperature detecting means arranged on the lower surface of the top plate for detecting the temperature of the load pan; and a temperature calculating means for calculating the temperature of the load pan from the output of the temperature detecting means, and the control means is calculated by the temperature calculating means. The induction heating cooker according to claim 1, wherein the accessory detection delay function is activated when the performed temperature is equal to or higher than a predetermined temperature. 2. A time measuring means for measuring an elapsed time from the start of heating, and the control means is configured to enable the accessory detection delay function when the time measured by the time measuring means is a predetermined time or more. Or the induction heating cooking appliance of 2. The current integration means for integrating the current detected by the input current detection means after the start of heating, and the control means enables the accessory detection delay function when the amount of current integrated by the current integration means is equal to or greater than a predetermined current amount. The induction heating cooker according to any one of claims 1 to 3, which is configured. The inverter circuit includes a resonance capacitor connected to the heating coil and a switching element, and the control means controls the heating output of the inverter circuit by increasing or decreasing the driving time of the switching element, and the accessory detection means is It is determined whether or not the load pan is suitable for heating based on the driving time of the switching element and the current detected by the input current detection means, and the output suppression means is responsive to the current detected by the input current detection means. The induction heating cooker according to any one of claims 1 to 4, wherein the driving time is suppressed. The inverter circuit includes a resonant capacitor connected to the heating coil and a switching element, the control means controls the output of the inverter circuit by increasing or decreasing the drive frequency of the switching element, and the accessory detection means It is determined whether or not the load pan is suitable for heating based on the driving frequency of the switching element and the current detected by the input current detecting means, and the output suppressing means is configured to control the switching element according to the current detected by the input current detecting means. The induction heating cooker according to any one of claims 1 to 4, wherein the drive frequency is suppressed. The induction heating cooker according to any one of claims 1 to 6, further comprising display means, wherein the control means is configured to display on the display means when the accessory detection delay function is valid. The induction heating cooker according to any one of claims 1 to 7, further comprising a notification unit, wherein the control unit is configured to perform notification by the notification unit when the accessory detection delay function is valid. The induction heating cooker according to any one of claims 1 to 8, further comprising a switching unit, wherein the control unit can switch whether or not to operate the accessory detection delay function by the switching unit. The induction heating cooker according to any one of claims 1 to 9, further comprising a time setting unit, wherein the control unit is configured to change a time for operating the accessory detection delay function by the time setting unit.