JP4545105B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker in which changes in heating output can be recognized by hearing.

  An induction heating cooker that emits a sound and gives an audible notification when the heating output changes is increasing. Considering the case where cooking is actually performed using an induction heating cooker, if the auditory alert is given when the heating output changes, the change in output can be confirmed without leaving the line of sight, making it easy to adjust the output, even for blind people. Output adjustment is possible. For this purpose, the conventional induction heating cooker that enables the auditory confirmation of the change in heating output includes a plurality of light emitting elements whose number of lighting is increased or decreased according to the level of the heating output level, and the above light emission. A sound generator that emits a sound each time the number of lighting of the element changes (for example, see Patent Document 1), or a device that visually displays and outputs a heating output (for example, Patent Document 1) 2).

Japanese Examined Patent Publication No. 6-65127 (Page 2, Fig. 1) Japanese Patent Laid-Open No. 10-253062 (first page, FIG. 3)

  The prior art exemplified in Patent Document 1 requires a sounding body such as a buzzer for auditory notification, and if the sound at the time of increase and decrease in heating output is different, the auditory notification means becomes complicated and expensive. There was a problem of inviting. In addition, if a sound is emitted only when the heating output changes, the judgment whether heating is performed or not depends only on the visual display, so if the visual display is hidden or the blind person is heated. It is difficult to judge whether it is heated or not heated. Further, in the prior art exemplified in Patent Document 2, a cooling fan used for cooling a heat-generating component is used as a sounding body for hearing notification. However, since the cooling fan is controlled in rotation speed together with the heating output, There was a problem that cooling may be insufficient.

  The present invention has been made to solve the above-mentioned problems of the prior art, and can notify a change in heating output with a simple configuration without requiring a sounding body such as a buzzer. On the other hand, it aims at providing the induction heating cooking appliance which can perform the efficient cooling according to the heat_generation | fever state.

Induction heating cooker according to the present invention includes a heating coil, an inverter circuit for supplying high-frequency power to the heating coil, in the induction heating cooker having a heating output setting section for the inverter circuit, the temperature of the inverter circuit A first temperature sensor to detect, a first cooling fan for cooling the inverter circuit, and a first rotational speed signal so that the temperature of the inverter circuit obtained from the first temperature sensor increases as the temperature increases. A first rotation speed control unit that outputs Vf1, and a second rotation speed signal Vf2 that temporarily increases immediately after increasing the heating output and temporarily decreases immediately after decreasing the heating output. A second rotation speed control unit, and the first rotation speed signal Vf1 and the second rotation speed signal Vf2 are added to obtain the rotation speed of the first cooling fan. An addition control unit, and the second rotation speed control unit has an absolute value of a change dVf2 / dt per unit time of the second rotation speed signal Vf2 immediately after increasing or decreasing the heating output. The signal Vf1 is controlled to be larger than the absolute value of the change dVf1 / dt per unit time .

In the present invention, the cooling fan control unit is configured to control the cooling fan based on the setting information of the heating output setting unit and the detection result of the temperature sensor that detects the absolute temperature of the inverter circuit. Efficient cooling can be performed according to the heat generated for the inverter circuit which is a member, and the operating status can be audibly notified by the sound generated by the cooling fan that accurately changes according to the increase or decrease of the heating output. Therefore, there is no need for a sounding body such as a buzzer, and the configuration can be simplified.

Embodiment 1 FIG.
1 to 8 illustrate an induction heating cooker according to Embodiment 1 of the present invention. FIG. 1 is a block diagram showing a main configuration, and FIG. 2 shows a relationship between heating output and heat generation of an inverter circuit. FIG. 3 is a diagram showing a half-bridge inverter circuit as an example of the inverter circuit, FIG. 4 is a diagram showing the relationship between the temperature of the inverter circuit and the first rotation speed, and FIG. 5 is a change in the set value of the heating output The figure which shows the time change of the temperature of the inverter circuit at the time, and the produced | generated 1st rotation speed, FIG. 6 is a figure which shows the time change of the 2nd rotation speed when the setting value of a heating output is changed, FIG. Is a diagram showing the relationship between the change amount of the heating output per unit time and the change amount of the second rotation speed per unit time, FIG. 8 is the first rotation speed when the set value of the heating output is changed, Second rotation speed, cooling fan rotation speed, and usage Is a diagram feel how the contrasted with the time axis will be explained with the rotation noise of the person. In the drawings, the same reference numerals denote the same or corresponding parts.

  In FIG. 1, the induction heating cooker operates a heating coil 2 that induction-heats a cooking container (load) 1 such as a pan, an inverter circuit 3 that supplies high-frequency power to the heating coil 2, and operates the inverter circuit 3. A heating output setting unit 5 provided in the operation unit 4, a temperature sensor 6 for detecting the temperature of the inverter circuit 3, a cooling fan 7 for cooling the heating coil 2 and the inverter circuit 3, and a heating output setting unit 5 A cooling fan control unit 8 that controls the cooling fan 7 based on the setting information and the detection result of the temperature sensor 6 is provided. The cooling fan 7 is intended to cool at least the inverter circuit 3, and a cooling fan for cooling the heating coil 2 may be separately provided.

The cooling fan control unit 8 includes the first rotation speed control unit 81 that outputs a signal corresponding to the first rotation speed Vf 1 based on the output of the temperature sensor 6, and the setting information of the heating output setting unit 5. Based on the second rotation speed control unit 82 that outputs a signal corresponding to the second rotation speed Vf2 based on the output signals of the first and second rotation speed control units 82 and 82. The rotational speed Vf is
Vf = Vf1 + Vf2
And an addition control unit 84 for controlling so that

  As the inverter circuit 3, a half-bridge inverter as shown in FIG. 3 is used in the first embodiment. The half-bridge inverter includes a series connection body of two switching elements 32a and 32b connected in parallel to the inverter power supply 31, diodes 33a and 33b connected in parallel to the switching elements 32a and 32b, and an inverter power supply. A snubber capacitor 34 connected in parallel to a switching element 32b (hereinafter referred to as an L arm) connected to the low potential side of 31 is provided, and the heating coil 2 and the resonance capacitor 35 are connected in series to the snubber capacitor 34. Connections are connected in parallel.

Next, regarding the operation of the first embodiment configured as described above, first, the relationship between the heating output P of the induction heating cooker and the heat generation of the inverter circuit will be described. As shown in FIG. 2, the heat generation of the inverter circuit is large when the heating output is small and when the heating output is large, and is small when the heating output is medium.
Hereinafter, the reason will be described in detail. The two switching elements 32a and 32b are alternately controlled at a constant frequency by a control circuit (not shown), and are connected to the high potential side of the inverter power supply 31 (hereinafter referred to as an H arm). The longer the conduction time, the larger the current flowing through the heating coil 2 and the greater the heating output.

  First, the current path when the H arm and L arm are turned on and off will be described. When the H arm is on, current flows through a path of the inverter power supply 31 to the H arm, the heating coil 2, the resonance capacitor 35, and the inverter power supply 31. Next, when the H arm is turned off (the L arm is also turned off), a current flows through a path from the snubber capacitor 34 to the heating coil 2 to the resonance capacitor 35 to the snubber capacitor 34. During this period, the voltage of the snubber capacitor 34 decreases. When the voltage of the snubber capacitor 34 becomes the same as the forward voltage of the diode 33b connected in parallel to the L arm, the diode 33b, the heating coil 2, the resonance capacitor 35, A current flows through the path of the diode 33b. Next, the L arm is turned on, and a current flows through a path from the L arm to the resonance capacitor 35 to the heating coil 2 to the L arm.

  Next, when the L arm is turned off (the H arm is also turned off), a current flows through a path from the snubber capacitor 34 to the resonance capacitor 35 to the heating coil 2 to the snubber capacitor 34, and the voltage of the snubber capacitor 34 increases. When the voltage of the snubber capacitor 34 becomes larger than the sum of the voltage of the inverter power supply 31 and the voltage of the diode 33a connected to the H arm, the inverter power supply 31 to the resonance capacitor 35 to the heating coil 2 to the diode 33a to the inverter power supply 31 are called. Current flows through the path. Then, the H arm is turned on and the above operation is repeated.

  However, when the heating output is small, the current flowing through the inverter circuit is small, and the voltage of the snubber capacitor 34 is reduced during the period in which the current flows through the path of the snubber capacitor 34 to the resonance capacitor 35 to the heating coil 2 to the snubber capacitor 34 described above. Increase slows down. Then, there is no period for the current to flow through the path of the inverter power supply 31 to the resonance capacitor 35 to the heating coil 2 to the diode 33a to the inverter power supply 31, and the current flows through the path of the snubber capacitor 34 to the resonance capacitor 35 to the heating coil 2 to the snubber capacitor 34. The H arm is turned on during the flowing period.

  At this time, since there is a difference between the voltage of the inverter power supply 31 and the voltage of the snubber capacitor 34, the H arm is turned on, so that a short circuit state occurs, and a very large current flows through the H arm and the snubber capacitor 34. As a result, a large loss occurs in the switching element 32a and the snubber capacitor 34, and heat generation of the inverter circuit increases when the heating output is small. When the heating output is increased, the current flowing through the inverter circuit increases, so that a very large current does not flow through the H arm and the snubber capacitor 34, and the inverter power supply 31 to the resonance capacitor 35 to the heating coil 2 to the diode 33a to the inverter power supply 31 are called. There is a period during which current flows through the path. When the heating output is further increased, the current flowing through the inverter is further increased and the heat generation of the inverter circuit is increased.

  As described above, the heat generation of the inverter circuit 3 is large when the heating output is small and when the heating output is large, and is small when the heating output is medium. That is, since the heating output and the heat generation of the inverter circuit are not in a proportional relationship, if the rotation speed of the cooling fan is controlled in proportion to the heating output, the inverter circuit will be undercooled when the heating output is small. When it is small, it is necessary to increase the rotation of the cooling fan. Hereinafter, the first embodiment that solves the problem of cooling of the inverter circuit at the same time will be described in more detail.

  In the first embodiment shown in FIG. 1, the rotational speed Vf of the cooling fan 7 is the first rotational speed Vf1 output from the first rotational speed control unit 81 and the first rotational speed Vf1 output from the second rotational speed control unit 82. 2 is controlled by the addition control unit 84 so that the rotation speed Vf2 of 2 is added (Vf = Vf1 + Vf2). The first rotation speed control unit 81 outputs the first rotation speed Vf1 based on the information obtained from the temperature sensor 6. The temperature sensor 6 is attached to a heat sink (not shown) attached to a switching element that generates a large amount of heat in the inverter circuit components. FIG. 4 shows the relationship between the temperature T of the inverter circuit 3 obtained from the temperature sensor 6 and the first rotational speed Vf1.

  The temperature T of the inverter circuit 3 and the first rotation speed Vf1 are in a proportional relationship as shown in FIG. 4, and the first rotation speed Vf1 is generated so as to increase as the inverter circuit 3 becomes higher in temperature. FIG. 5 shows the time (t) change of the temperature T of the inverter circuit 3 and the time (t) of the first rotation speed Vf1 when the set value of the heating output P is changed. . The amount of change dVf1 / dt of the first rotation speed Vf1 per unit time is reduced so that the rotation sound of the cooling fan 7 changes during the same heating output and the user does not feel that the heating output has changed. Is set to For example, dVf1 / dt can be reduced by increasing the heat capacity of the inverter circuit 3 by increasing the heat sink (not shown).

  On the other hand, the second rotation speed control unit 82 outputs the second rotation speed Vf <b> 2 based on the heating output information from the heating output setting unit 5. FIG. 6 shows the relationship between the second rotation speed Vf2 generated according to the change in the heating output P and the time t. When the heating output P is increased, the second rotation speed Vf2 is temporarily increased, and when the heating output P is decreased, the second rotation speed Vf2 is temporarily decreased. FIG. 7 shows the relationship between the change amount dVf2 / dt of the second rotational speed Vf2 per unit time when the heating output P increases or decreases, and the change amount dP / dt of the heating output. The absolute value of dVf2 / dt increases as the absolute value of dP / dt increases. Note that the sum of Vf1 and Vf2 is set to be positive.

  FIG. 8 is a diagram showing how the parameters such as the time change of the rotational speed Vf (= Vf1 + Vf2) of the cooling fan 7 due to the change of the heating output P and the change of the rotation sound of the cooling fan 7 by the user are perceived. The rotation speed Vf of the cooling fan 7 temporarily increases or decreases when the heating output P changes, so that the second rotation speed Vf2 increases or decreases temporarily. When the heating output P is constant, the rotation speed Vf increases with the temperature of the inverter circuit 3. Since Vf1 changes, Vf also changes according to the change. Here, considering how the user feels the change in the rotation sound of the cooling fan 7, when the heating output P is constant, the change in the rotation speed of the cooling fan 7 is small, so the user can detect the rotation sound of the cooling fan 7. Little change is felt.

  On the other hand, when the heating output P increases, the rotation speed of the cooling fan 7 increases rapidly, so that the user feels that the rotation sound of the cooling fan 7 has suddenly increased. Since the rotation speed of the fan 7 decreases rapidly, the user feels that the rotation sound of the cooling fan 7 has suddenly decreased. Therefore, as shown in the lowermost graph of FIG. 8, the user feels that the rotation sound suddenly changes in magnitude when the heating output P is changed.

  In the above description, the case where the heating output P is increased from the middle has been described as an example. However, when the heating output P is reduced and the temperature of the inverter circuit 3 rises, the temperature sensor 6 detects this, Since the first rotation speed control unit 81 increases the first rotation speed Vf1 in proportion to the detected temperature, the rotation speed of the cooling fan 7 is increased and the cooling of the inverter circuit 3 is not impaired. Further, since the increase in the rotational speed of the cooling fan 7 due to the temperature rise is moderate, it is possible to prevent the user from feeling uncomfortable.

  As described above, according to the first embodiment, the cooling fan control unit 8 is based on the setting information of the heating output setting unit 5 and the detection result of the temperature sensor 6 that detects the temperature of the inverter circuit 3. The cooling fan can perform efficient cooling according to the heat generated for the inverter circuit 3 that is a heat generating member, and is performed in response to a change in heating output. 7 can be audibly informed as a change in the sound generated by the cooling fan 7, that is, an increase / decrease in the rotational sound, so there is no need to separately provide a sounding body such as a buzzer or its control circuit, and the notification means is simplified. Can be

  The rotational speed of the cooling fan 7 is the sum of the first rotational speed Vf1 output from the first rotational speed controller 81 and the second rotational speed Vf2 output from the second rotational speed controller 82. The first rotation speed Vf1 proportional to the temperature of the inverter circuit 3 decreases the change dVf1 / dt per unit time, and the second rotation speed Vf2 changes rapidly per unit time dVf2 / dt that rapidly increases or decreases when the heating output changes. Since dt is made larger than dVf1 / dt, the user can determine the increase or decrease in the heating output P by a sudden change in the rotational sound of the cooling fan 7. In addition, since efficient cooling without insufficient cooling or overcooling of the inverter circuit 3 can be performed at the same time, energy saving of the power consumption of the cooling fan 7 and long life of the cooling fan 7 can be expected.

  Further, as the change amount dVf2 / dt of the second rotation speed Vf2 per unit time is increased, the user is less likely to feel the change in the rotation sound due to the change amount dVf1 / dt of the first rotation speed Vf1 per unit time. Become. Therefore, dVf1 / dt can be increased, and the heat capacity of the inverter circuit 3 can be reduced. When the heat capacity of the inverter circuit 3 is reduced, the heat sink (not shown) can be reduced in size. In the first embodiment, the first rotation speed control unit 81, the second rotation speed control unit 82, and the addition control unit 84 are provided separately. However, the present invention is not limited to this. For example, the same control is performed. These functions may be provided by a microcomputer.

Embodiment 2. FIG.
FIG. 9 is a block diagram illustrating an induction heating cooker according to Embodiment 2 of the present invention. In the second embodiment, in addition to the configuration of the first embodiment, a heating coil temperature sensor 6B that detects the temperature of the heating coil 2 and a third rotation speed Vf3 based on the detection result of the heating coil temperature sensor 6B. Output signals of the third rotation speed control unit 83 that outputs a signal corresponding to the above, the heating coil cooling fan 7B that cools the heating coil 2, and the third rotation speed control unit 83 and the second rotation speed control unit 82. Based on this, a second addition control unit 84B is provided for controlling the rotation speed Vb of the heating coil cooling fan 7B to be Vb = Vf2 + Vf3. The cooling fan control unit 8 includes the first, second, and third rotation speed control units 81, 82, and 83, an addition control unit 84, and a second addition control unit 84B. .

  In the second embodiment, the third rotation speed Vf3 output from the third rotation speed control unit 83 based on the temperature information obtained by the heating coil temperature sensor 6B attached to the heating coil 2 is large. And the variation | change_quantity per unit time is determined similarly to 1st rotation speed Vf1. The rotation speed Vb of the heating coil cooling fan 7B is an addition of the third rotation speed Vf3 and the second rotation speed Vf2. At this time, similarly to the first embodiment, control is performed such that the change dVf2 / dt per unit time of Vf2 is larger than the changes dVf1 / dt and dVf3 / dt of Vf1 and Vf3 per unit time. That is, the cooling fan control unit 8 determines the change dVf2 / dt per unit time of the second rotation speed Vf2 when the heating output P is increased or decreased according to the setting information of the heating output setting unit 5. The rotation speed Vf3 is controlled to be larger than the change dVf3 / dt per unit time.

  As a result, in the second embodiment, when the heating output P is increased or decreased by the heating output setting unit 5, the cooling fan 7 that cools the inverter circuit 3 and the heating coil cooling fan 7B that cools the heating coil 2 are provided. Since both of the cooling fans change the rotating sound abruptly, the changing sound is emphasized, and the increase / decrease in the heating output to the user can be notified more effectively. Moreover, since a required location can be individually cooled by a plurality of cooling fans, an improvement in cooling performance can be expected. When a plurality of heat generating parts such as the heating coil 2 and the inverter circuit 3 are provided, for example, a cooling fan is provided in each heat generating part, and each cooling fan is controlled simultaneously by one cooling fan control unit 8. It can also be configured as follows.

Embodiment 3 FIG.
FIG. 10 is a diagram showing another control example of the induction heating cooker according to Embodiment 3 of the present invention. The heating output P, the first rotational speed Vf1, the second rotational speed Vf2, and the rotational speed Vf of the cooling fan 7 are shown. It is a figure which shows how a user feels the rotation sound of a cooling fan, and the relationship of time. The difference from the first embodiment is that, as shown in the figure, the second rotational speed Vf2 is increased rapidly when the heating output P is increased, and then the second rotational speed Vf2 per unit time when the heating output is changed. The rotation speed is decreased slowly with a small change compared to dVf2 / dt, and when the heating output P is decreased, the rotation speed is rapidly decreased and then slowly increased with a small change compared to dVf2 / dt. That is. The dVf2 / dt is set so as not to cause insufficient cooling of the heat-generating component when the second rotational speed Vf2 is slowly increased or decreased. Since the other configuration is the same as that of the first embodiment, the following description will be given with reference to FIG.

  In the third embodiment, when the heating output P is increased, the rotation speed Vf of the cooling fan 7 is rapidly increased and then only gradually decreased. Therefore, the user feels that the rotation is abrupt as shown in the figure. After going up, it feels constant. Further, since the rotation of the cooling fan 7 is generally maintained in an increased state as shown in the graph of time variation of Vf, the cooling power for the inverter circuit 3 which is a heat generating component becomes sufficient, and the temperature T of the inverter circuit 3 is increased. The first rotation speed Vf1 generated in proportion is changed so as to draw a gradually rising curve after a slight decrease immediately after the heating output P is increased as shown in the figure.

  As described above, according to the third embodiment, the user feels the rotation sound of the cooling fan 7 in the same manner as the heating output P by controlling the second rotation speed Vf2 as described above. That is, when the heating output P changes, the rotation sound of the cooling fan 7 changes abruptly. When the heating output P is constant, the change in the rotation speed of the cooling fan 7 is small. Because there is no. Thereby, the induction heating cooking appliance which a user's heating adjustment becomes easy can be provided. In addition, efficient cooling that does not cause insufficient cooling or overcooling of the heat-generating components can be performed, and energy saving and longer life of the cooling fan can be expected.

The block diagram which shows the principal part structure of the induction heating cooking appliance by Embodiment 1 of this invention. The figure which shows the relationship between the heating output in Embodiment 1, and the heat_generation | fever of an inverter circuit. The figure which shows the half-bridge inverter circuit as an example of the inverter circuit shown in FIG. The figure which shows the relationship between the temperature of the inverter circuit shown in FIG. 1, and a 1st rotational speed. The figure which shows the time change of the temperature of an inverter circuit when the setting value of a heating output is changed in Embodiment 1, and the produced | generated 1st rotational speed. The figure which shows the time change of the 2nd rotational speed when the setting value of a heating output is changed in Embodiment 1. FIG. In Embodiment 1, it is a figure which shows the relationship between the variation | change_quantity of the heating output per unit time, and the variation | change_quantity of the 2nd rotational speed per unit time. The first rotation speed, the second rotation speed, the cooling fan rotation speed, and the user's feeling of the rotation sound when the set value of the heating output is changed in the first embodiment are compared on the time axis. FIG. The block diagram explaining the induction heating cooking appliance by Embodiment 2 of this invention. The figure which shows the other example of control of the induction heating cooking appliance by Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooking container (load), 2 Heating coil, 3 Inverter circuit, 31 Inverter power supply, 32a Switching element (H arm), 32b Switching element (L arm), 33a, 33b Diode, 34 Snubber capacitor, 35 Resonance capacitor, 4 Operation 5, heating output setting unit, 6 temperature sensor, 6B heating coil temperature sensor, 7 cooling fan, 7B heating coil cooling fan, 8 cooling fan control unit, 81 first rotation speed control unit, 82 second rotation speed control 83, third rotation speed control unit, 84 addition control unit, 84B second addition control unit, P heating output, T inverter circuit temperature, t time, Vf1 first rotation speed, Vf2 second rotation speed Vf3 Third rotational speed, Vf Cooling fan rotational speed, Vb Heating coil cooling fan rotational speed

Claims (4)

In an induction heating cooker including a heating coil, an inverter circuit that supplies high-frequency power to the heating coil, and a heating output setting unit for the inverter circuit, a first temperature sensor that detects the temperature of the inverter circuit; first rotational speed to output a first cooling fan for cooling the inverter circuit, a first rotational speed signal Vf1 so that the temperature of the inverter circuit obtained from the first temperature sensor increases as the temperature rises A control unit, a second rotation speed control unit that outputs a second rotation speed signal Vf2 that temporarily increases immediately after increasing the heating output and temporarily decreases immediately after decreasing the heating output; A first addition controller that adds the first rotational speed signal Vf1 and the second rotational speed signal Vf2 to obtain the rotational speed of the first cooling fan, The rotation speed control unit determines that the absolute value of the change dVf2 / dt per unit time of the second rotation speed signal Vf2 immediately after increasing or decreasing the heating output is the change dVf1 / dt of the first rotation speed signal Vf1 per unit time. An induction heating cooker that is controlled to be larger than the absolute value of . A second cooling fan for cooling the heating coil, a second temperature sensor for detecting the temperature of the heating coil, and a temperature of the heating coil obtained from the second temperature sensor so as to increase as the temperature increases. A third rotational speed control unit that outputs a third rotational speed signal Vf3; and the third rotational speed signal Vf3 and the second rotational speed signal Vf2 are added to determine the rotational speed of the second cooling fan. A second addition control unit that performs the absolute value of the change dVf2 / dt per unit time of the second rotation speed signal Vf2 immediately after increasing or decreasing the heating output. 2. The induction heating cooker according to claim 1, wherein the induction heating cooker is controlled to be larger than an absolute value of a change dVf3 / dt of the third rotation speed signal Vf3 per unit time . In an induction heating cooker including a heating coil, an inverter circuit that supplies high-frequency power to the heating coil, and a heating output setting unit for the inverter circuit, a first temperature sensor that detects the temperature of the inverter circuit; The first rotation speed for outputting the first rotation speed signal Vf1 so that the temperature of the inverter circuit obtained from the first cooling fan for cooling the inverter circuit and the first temperature sensor increases as the temperature increases. The control unit increases rapidly immediately after increasing the heating output, then decreases slowly with respect to the change immediately after decreasing the heating output, decreases rapidly immediately after decreasing the heating output, and then heats A second rotation speed control unit that outputs a second rotation speed signal Vf2 that slowly increases with respect to a change immediately after the output is decreased; and the first rotation speed. And a second addition controller that adds the second rotation speed signal Vf2 to the rotation speed of the first cooling fan, and the second rotation speed control section increases or decreases the heating output. The absolute value of the change dVf2 / dt per unit time of the second rotation speed signal Vf2 immediately after is greater than the absolute value of the change dVf1 / dt of the first rotation speed signal Vf1 per unit time. And the induction heating cooker characterized by controlling so that it may become larger than the absolute value of change dVf2 / dt per unit time of 2nd rotational speed signal Vf2 other than immediately after increasing / decreasing a heating output . A second cooling fan for cooling the heating coil, a second temperature sensor for detecting the temperature of the heating coil, and a temperature of the heating coil obtained from the second temperature sensor so as to increase as the temperature increases. A third rotational speed control unit that outputs a third rotational speed signal Vf3; and the third rotational speed signal Vf3 and the second rotational speed signal Vf2 are added to determine the rotational speed of the second cooling fan. A second addition control unit that performs the absolute value of the change dVf2 / dt per unit time of the second rotation speed signal Vf2 immediately after increasing or decreasing the heating output. The change dV per unit time of the second rotation speed signal Vf2 other than immediately after the heating output is increased or decreased so as to be larger than the absolute value of the change dVf3 / dt of the third rotation speed signal Vf3 per unit time. Induction heating cooker according to claim 3, wherein the controller controls so as to be larger than the absolute value of the 2 / dt.

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