JP2009295330A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To display the heating efficiency of a heated cooking utensil in induction heating cooking. <P>SOLUTION: The heating efficiency is calculated by an input current and an output current to and from an inverter circuit, supplying high-frequency current to a heating coil. The heating efficiency calculated is displayed on an efficiency display part 49 provided at a top plate. A user is able to find out from the heating efficiency displayed whether the heated cooking utensil is suited for induction heating. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an induction heating cooking apparatus that uses an inverter circuit to induction-heat cooked utensils.

In an induction heating cooking device (electromagnetic cooker), a high-frequency current is supplied to a heating coil using an inverter circuit to induction-heat a cooked utensil. In the induction heating cooking apparatus using this inverter circuit, when the power is turned on, first, the material of the cooking utensil such as a pan placed on the top plate is determined, and then the high frequency of the frequency according to the material is determined. The switching element of the inverter circuit is on / off controlled so that current is supplied to the heating coil (for example, Patent Document 1).
Japanese Patent No. 3826102

  In the conventional induction heating cooking apparatus, when the heating power is adjusted by operating the operation unit during cooking, the adjusted heating power is displayed on the display. However, this display does not display the actual amount of heating of the cooked utensils. In other words, the cooked utensils include various materials such as an aluminum pan, an iron pan, and a clad pan of aluminum and iron. In an aluminum pan, even if a large high-frequency current is supplied to the heating coil, the heating value of the pan is relatively small, and it takes a long time to boil the hot water. However, in an iron pan, even if the high-frequency current supplied to the heating coil is small, the amount of heat generated by the pan is relatively large, and hot water can be boiled in a shorter time than an aluminum pan.

  If possible, it is convenient for energy saving that the cooked utensil used in the induction heating cooking apparatus is made of a material having a large calorific value even if the high-frequency current supplied to the heating coil is small. However, the conventional induction heating cooking device does not display the magnitude of the actual calorific value of the cooking utensil by the strength display of the set heating power. There was no way of knowing whether the material was suitable for heating, and there was no other way than to judge it sensuously based on the length of time it took to boil.

  This invention is made | formed in view of said situation, The objective is to provide the induction heating cooking apparatus which can display whether it is a to-be-heated cooking appliance suitable for induction heating.

  The induction heating cooking apparatus of the present invention detects the heating efficiency based on the output current detection means for detecting the output current of the inverter circuit and the magnitude of the output current to the inverter circuit detected by the output current detection means. It comprises heating efficiency detection means and display means for displaying the heating efficiency detected by the heating efficiency detection means.

  According to the present invention having the above configuration, since the heating efficiency according to the cooked utensil actually used is displayed, it is possible to easily determine whether the cooked utensil is of a material suitable for induction heating. it can.

Hereinafter, several embodiments in which the present invention is applied to an induction heating cooking apparatus incorporated in a system kitchen will be described with reference to the drawings.
[First Embodiment]
1 to 7 show a first embodiment of the present invention. 3-5 shows the whole structure of a heating cooker, and the heating cooker main body 1 is, as shown in FIG. The lower unit 4 is located below the upper unit 3 and is fitted into the cooking table 2 from the front and assembled.

  The upper unit 3 includes a case 5 and a top plate 6 that closes the upper surface opening of the case 5. Two coil bases 7 (only one is shown) are disposed on the left and right sides of the front side of the case 5 so as to be positioned directly below the top plate 6. On each of the coil bases 7, an induction heating cooking device is provided. The heating coil 8 which is the main body is attached. Although not shown in the figure, a radial end heater is disposed in the center of the rear side in the case 5.

  The top plate 6 is formed in a flat rectangular shape from heat-resistant tempered glass. As shown in FIGS. 3 and 4, on the top surface of the top plate 6, a heating unit for instructing a placement unit suitable for heating a cooking utensil T such as a pan (see FIG. 3) at three locations. 9 to 11 are printed and displayed as circular lines. Among these heating units 9 to 11, the left and right heating units 9 and 10 on the front side correspond to the two heating coils 8, and the heating unit 11 at the center on the rear side corresponds to a not shown radiator end heater. Is.

  On the other hand, as shown in FIGS. 3 and 5, the lower unit 4 includes a roaster 12 on the left side and a control unit 13 and a blower fan device 14 on the right side. The roaster 12 is configured using, for example, a sheathed heater (not shown) as a heat source. The front portion of the control unit 13 is an operation panel 15. The operation panel 15 is used for individually turning on / off or adjusting the output of the power switch 16 for turning on / off the heating cooker, the left and right heating coils 8, the radial end heater, and the sheath heater of the roaster 12. Four dials 17 and the like are provided.

  As shown in FIG. 4, heating coil output display portions 18 and 19 are printed on the top plate 6 so as to surround the front portions of the heating portions 9 and 10 of each heating coil 8. In addition, an output display unit 20 for the radial end heater is printed and displayed at the front center of the top plate 6. A plurality of light emitting diodes (not shown) are provided below the output display portions 18 to 20, and the number of light emitting diodes according to the output adjustment by each heating coil 8 and the dial 17 of the radial end heater is provided. By turning on, the adjusted output (heat power) can be visually confirmed.

  FIG. 7 shows an electrical configuration for heating control by the heating coil 8. In the present embodiment, two heating coils 8 are provided. FIG. 7 shows an electrical configuration of one heating coil. Further, FIG. 7 shows only a part related to the control of the heating coil 8, and does not show the blower fan device 14, the light emitting diodes of the output display units 18 to 20, and the like. In FIG. 7, an AC power supply 21 is connected to a DC power supply circuit 22. The DC power supply circuit 22 includes a bridge circuit 23 for rectifying the AC power supply and a capacitor 24 for smoothing the rectified pulsating flow.

  The inverter circuit 25 using the DC power supply circuit 22 as a power source is a half-bridge type, and includes two IGBTs (switching elements) 26 and 27, and diodes 28 and 29 connected between collectors and emitters of the IGBTs 26 and 27, respectively. A series resonance circuit connected to the output terminal of the inverter circuit 25 and the positive and negative output lines of the DC power supply circuit 22, which is composed of the heating coil 8 and the resonance capacitor 30 in this embodiment.

The inverter voltage phase detection circuit 31 detects the inverter voltage V _IN as the first signal, and outputs the detected inverter voltage V _IN to the phase comparison circuit 32. The capacitor voltage phase detection circuit 33 detects the voltage Vc ₁ at both ends of the capacitor 24 as a second signal phase-correlated with the inverter current flowing through the capacitor 24, and outputs the detected voltage Vc ₁ to the phase comparison circuit 32. To do.

The phase comparison circuit 32 compares the phases of both the input first signal and the second signal, and outputs a comparison result, that is, a signal V _P1 related to the phase difference between the two signals, to the difference comparison circuit 34. The phase difference setting circuit 35 variably sets the phase difference V _SET between the first signal and the second signal described above. The input power is adjusted according to the variably set phase difference V _SET .
The difference comparison circuit 34 compares the phase difference signal V _P1 output from the phase comparison circuit 32 with the phase difference signal V _SET variably set in the phase difference setting circuit 35, and compares the comparison result V _P2 . The voltage is output to a voltage controlled oscillator (hereinafter referred to as VCO) 36. That is, if V _P1 > V _SET , V _P2 = H is output, and if V _P1 ≦ V _SET , V _P2 = L is output. The VCO 36 is frequency control means for controlling the oscillation frequency of the inverter circuit 25 so that the phase difference variably set by the phase difference setting circuit 35 is obtained. In accordance with the output signal V _P2 from the difference comparison circuit 34. Change the oscillation frequency.

  The drive circuit 37 alternately turns on and off the IGBTs 26 and 27 based on the signal from the VCO 36. When the IGBTs 26 and 27 are alternately turned on and off based on the signal from the drive circuit 37, the heating coil 8 and the capacitor 30 are set in a series resonance state, whereby the heating coil 8 generates high frequency power and the top plate 6 The to-be-heated cooking appliance T, such as a pan which is loaded, is induction-heated.

  The input-side current transformer 38 detects a power supply current supplied from the AC power supply 21 and outputs a signal corresponding to the detected power supply current to the input current detection circuit 39. The input side current transformer 38 functions as input current detection means for detecting an input current to the inverter circuit 25. The input current detection circuit 39 detects the input current based on the detection signal from the input side current transformer 38.

  The load state detection circuit 40 detects whether or not the load placed on the top plate 6 is an appropriate load based on information from the input current detection circuit 39. The input side voltage detector 41 as the input voltage detection means outputs a signal corresponding to the voltage of the AC power supply 21 to the input voltage detection circuit 42. The input voltage detection circuit 42 detects the voltage of the AC power supply 21 based on the detection signal from the input side voltage detector 41. The input side voltage detector 41 is composed of, for example, a voltage dividing resistor circuit.

  Further, an output-side current transformer 43 is provided at a portion where the emitter of the IGBT 26 and the heating coil 8 are connected, and an output signal of the output-side current transformer 43 is detected via the inverter current detection circuit 44. The circuit 40 is provided. The output-side current transformer 43 functions as output current detection means for detecting the output current of the inverter circuit 25 (coil current flowing through the heating coil 8; also referred to as inverter current).

  In addition, the input port of the A / D converter 45 includes the positive output terminal of the bridge circuit 5, the output terminal of the inverter circuit 25, the input current detection circuit 39, the input voltage detection circuit 42, and the output of the inverter current detection circuit 44. Each is connected to a terminal. The A / D converter 45 multiplexes the input voltage, output voltage, input current, and output current of the inverter circuit 25 to perform A / D conversion. For the output voltage detection of the inverter circuit 25, a voltage dividing resistor (not shown) is provided as necessary. Here, connecting the positive output terminal of the bridge circuit 5 to the input port of the A / D converter 45 detects the output voltage of the inverter circuit 25 (substantially equal to the voltage applied to the heating coil 8). Therefore, this has a function as an output voltage detection means.

  In this embodiment, the phase comparison circuit 32, the difference comparison circuit 34, the phase difference setting circuit 35, the VCO 36, the load state detection circuit 40, the A / D conversion unit 45, a heating efficiency detection unit (heating efficiency detection means described later) ) 46 and the display control unit 47 constitute a control circuit (control means) 48. The control circuit 48 is constituted by a microcomputer (RISC microcomputer) having a CPU core of RISC architecture.

  In the present embodiment, at the start of heating by the heating coil 8, first, the material determination of the cooked utensil (load) is performed. In this material determination, the switching frequency of the inverter circuit 25 is changed so that the output current of the inverter circuit 25 is constant, and the material determination is performed according to the value of the input current from the AC power source 21 at the time when the inverter circuit 25 becomes constant. The first determination method may be used, and when the switching frequency of the inverter circuit 25 is lowered step by step, the material is determined from the input current and output current of the inverter circuit 25 (first determination method). 2 determination method).

  According to the first determination method, the input current increases in the order of aluminum, nonmagnetic stainless steel (SUS), clad material of aluminum and iron, and iron, so that the material of the load can be determined. According to the second determination method, when the switching frequency is set to, for example, 70 KHz, the aluminum material has a tendency that the input current hardly flows and the output current flows relatively much. When the switching frequency is set to, for example, 50 KHz, Magnetic stainless steel has a tendency to flow both input current and output current, iron has a tendency to have a large input current and a low output current, and cladding material tends to be intermediate between nonmagnetic stainless steel and iron. The material can be determined.

  Then, when the material determination is completed, the process proceeds to normal heating cooking, and the drive circuit 37 determines that the phase difference between the output voltage and the output current of the inverter circuit 25 is determined as described above. The IGBTs 26 and 27 are controlled to be turned on and off so that the values correspond to the load state detected by the load state detection circuit 40 from the material, the input current and the output current, and the output (heat power) adjusted by the user.

The relationship between the material of the cooked utensil during normal cooking and the input current and output current of the inverter circuit 25 is as shown in the characteristic diagram of FIG.
Now, in this embodiment, as shown in FIG. 3 and FIG. 4, the efficiency which displays the heating efficiency at the time of heating a to-be-heated cooking utensil with each heating coil 8 on the right-and-left both sides of the front part of the upper surface of the top plate 6. A display unit (display means) 49 is provided. As shown in FIG. 2, the efficiency display unit 49 includes a transparent portion 6a provided on the top plate 6 and a light emitting display portion (light emitting display means) 50 provided on the back surface of the transparent portion 6a. ing. The light-emitting display unit 50 in this case includes a 7-segment light-emitting diode (numerical display) for displaying numbers, a plurality of light-emitting diode groups, a fluorescent display tube, a liquid crystal display, and the like. is there.

  The heating efficiency detection unit 46 and the display control unit 47 included in the control circuit 48 calculate the heating efficiency of the heating coil 8 during the normal heating cooking, and display the calculated heating efficiency on the efficiency display unit 49. Is. In this embodiment, the heating efficiency detector 46 is configured to calculate the heating efficiency based on the ratio between the input current and the output current of the inverter circuit 25.

  Here, the heating efficiency refers to the ratio between the input power (input power from the AC power supply 21) and the amount of heat received by the water in the cooking utensil (how much the temperature has been heated). Ideally, all of the input power only needs to be converted into heat, but in reality, the loss in the inverter circuit 25, the power consumption of the blower fan device 14 that cools the heating coil 8, and the air from the cooking utensil to be heated Loss of heat dissipation inside.

  This loss is about 10% for iron cookware, 15% for clad material, 25% for nonmagnetic stainless steel, and about 70% for aluminum. Therefore, the standard of the heating efficiency is 90% for iron cooked utensils, 85% for clad material, 75% for nonmagnetic stainless steel, and 30% for aluminum. The relationship between each material and the standard heating efficiency is stored in a memory (storage means) (not shown) of the control circuit 48.

  Although the material is known by the material determination, the material can be determined by calculating the ratio between the input current and the output current even after the actual cooking. This can be understood from the characteristic lines of the respective materials showing the relationship between the input current and the output current in FIG. In practice, the ratio of the input current to the output current of the cooked utensils of each material does not necessarily match the characteristic line of each material shown in FIG. 6, but the characteristic line of each material shown in FIG. By taking into account variations from the above, correct material determination can be performed with high probability.

When the material of the cooked utensil is determined, the actual output current / input current value is multiplied by the inverse of the slope of the characteristic line (output current / input current) of the material shown in FIG. The product is multiplied by the standard heating efficiency of the material. This is the heating efficiency of the cooked utensil at that time.
That is, if the slope of the characteristic line in FIG. 6 is F for iron, C for clad material, S for nonmagnetic stainless steel, and A for aluminum, the actual output current / input current value is the same as the slope of the characteristic line. When the cooking utensil is made of iron and the actual output current / input current value is F, the clad material is C, the nonmagnetic stainless steel is S, and the aluminum is A, the heating efficiency is the iron cooking utensil. 90%, made of clad material 85%, made of nonmagnetic stainless steel 75%, made of aluminum 30%.

  If the actual output current / input current value is different from the slope of the characteristic line of the determined material, for example, if the cooked utensil is made of iron, the output current is 3 amps, and the input current is 9 amps, The efficiency is 90 × F × 3/9.

The heating efficiency thus obtained is displayed on the light emitting display unit 50 under the control of the display control unit 47.
In this embodiment, a 7-segment light-emitting diode that displays numbers is used as the light-emitting display unit 50, and the heating efficiency is displayed by numbers on the light-emitting display unit 50 as shown in FIG. It is assumed that the symbol “%” is printed on the top plate 6 in advance. This display is obtained and displayed as described above from the ratio between the output current and the input current during heating. For this reason, the input current increases and the output current decreases when the cooked utensil deviates from its normal position by, for example, stirring food in the cooked utensil during heating. Heating efficiency is reduced. Since this reduced heating efficiency is displayed on the efficiency display section 49, the user notices the positional deviation of the cooked utensil and corrects the position. In this case, a decrease in heating efficiency may be notified (informing means) by a buzzer or the like.
Thus, according to this embodiment, since the heating efficiency of the cooking utensil to be used is displayed, the user visually confirms whether the cooking utensil to be heated is suitable for induction heating or not. can do.

[Second Embodiment]
FIG. 8 shows a second embodiment of the present invention. In this embodiment, a plurality of light emitting diode groups are used as the light emitting display unit 50, the plurality of light emitting diodes 50a are arranged in a horizontal row or a vertical row, and a number of light emitting diodes are turned on according to the heating efficiency, thereby heating. Display efficiency in a bar graph.

[Third Embodiment]
FIG. 9 shows a third embodiment of the present invention. In this embodiment, the heating efficiency detector 46 regards the heating efficiency of the iron cooked utensil as 100% (actually 90%) and calculates the relative heating efficiency for the iron cooked utensil. It is configured as follows. And this relative heating efficiency is displayed on the efficiency display part 49. FIG. For example, when the determined cooking utensil is made of nonmagnetic stainless steel, the heating efficiency of the nonmagnetic stainless steel is 75%. In this case, the heating efficiency displayed on the efficiency display unit 49 is 83 ( = 75/90)% is displayed.

[Fourth Embodiment]
FIG. 10 shows a fourth embodiment of the present invention. In this embodiment, when 1 liter of water is put into a pot made of various materials and heated at the maximum heating power within an adjustable range, the time required for boiling (water boiling time) is measured, and the result is stored in advance in a memory. It is registered.
When the heating efficiency detector 46 determines the material of the cooked utensil from the input current and output current of the inverter circuit 25, the heating efficiency detection unit 46 acquires the boiling time corresponding to the material from the memory and displays it on the efficiency display unit 49. Is.
Even if comprised in this way, since the boiling time is the time when the heating efficiency is taken into account, it is possible to easily discriminate between those having good heating efficiency and those not.
[Fifth Embodiment]
FIG. 11 shows a fifth embodiment of the present invention. In this embodiment, for example, when 1 liter of water is put into a pot made of various materials and when 2 liters of water is put, it takes time to boil when heated at the maximum heating power within an adjustable range. Time is measured and the result is registered in the memory according to the amount of water.
When the heating efficiency detection unit 46 determines the material of the cooked utensil from the input current and output current of the inverter circuit 25, the heating efficiency detection unit 46 acquires the boiling time for each amount of water corresponding to the material from the memory and displays it on the efficiency display unit 49. .
If the boiling time according to the amount of water is displayed in this way, it becomes easier to compare the actual amount of water that has been put into the cooking utensil during actual use with the displayed boiling time, and whether or not it is suitable for induction heating. Can be more easily determined.

[Sixth Embodiment]
FIG. 12 shows a sixth embodiment of the present invention. In this embodiment, when the heating efficiency detector 46 determines the material of the cooking utensil from the input current and output current of the inverter circuit 25, a symbol or icon corresponding to the material is displayed on the efficiency display 49. In this embodiment, when the material of the cooked utensil is iron, “◎” as shown in FIG. 12A, and when it is a clad material, “◯” as shown in FIG. In the case of magnetic stainless steel, “Δ” is displayed as shown in FIG. 12C, and in the case of aluminum, “X” is displayed as shown in FIG. 12D. For this reason, the user can judge intuitively whether it is suitable for induction heating.

[Seventh Embodiment]
FIG. 13 shows a seventh embodiment of the present invention. In this embodiment, when the heating efficiency detection unit 46 calculates the current heating efficiency as described in the second or third embodiment, the display control unit 47 returns to a predetermined time before the predetermined time. The change in heating efficiency from before the current time to the current time is displayed on the efficiency display section 49 by a graph.
If it is such a display, when it becomes difficult to heat a to-be-heated cooking utensil from a regular position, this will be understood immediately by the graph currently displayed on the efficiency display part 49. FIG.

[Eighth Embodiment]
FIG. 14 shows an eighth embodiment of the present invention. In this embodiment, the heating efficiency detection unit 46 multiplies the input voltage detected by the input voltage detection circuit 42 and the input current detected by the input current detection circuit 39 to obtain instantaneous power during heating. The display control unit 47 displays the instantaneous power calculated by the heating efficiency detection unit 46 on the efficiency display unit 49 in a graph.
Even in this way, the heating efficiency of the cooking utensil to be heated can be determined by the magnitude of the electric power (the length of the bar graph). In this case, if the iron instantaneous power is printed and displayed in the vicinity in the form of a bar graph, it is possible to relatively determine whether the heating efficiency is good or bad compared to the case of iron.

By the way, when the cooked utensil is made of aluminum or non-magnetic stainless steel, if it is set to high heating power, a large current may flow through the inverter circuit 25 and the IGBTs 26 and 27 may be destroyed. It is provided so that no current exceeding the set current value flows. In consideration of such circumstances, it can be seen that the current is limited when the power value is low even though it is set to a high heating power. I know that there is.
The instantaneous power may be obtained from the output voltage and output current of the inverter circuit 25.

[Ninth Embodiment]
FIG. 15 shows a ninth embodiment of the present invention. In this embodiment, the heating efficiency detector 46 obtains the instantaneous power in the same manner as in the eighth embodiment. In this embodiment, for example, a counter for integration (not shown) as an integration unit is connected to the heating efficiency detector 46, and the calculated instantaneous power is sequentially counted. Then, the display control unit 47 displays the integrated power stored in the integration counter on the efficiency display unit 49 as a bar graph.
In this case, the integrated power is preferably used in combination with the efficiency display as shown in FIGS. 1, 8, and 9, for example.
Thus, according to this embodiment, since the amount of electric power actually used is known even when boiling hot water, a more efficient cooked appliance to be used is used, which is useful for energy saving.

[Other Embodiments]
The present invention is not limited to the embodiments described above and shown in the drawings, and can be expanded or changed as follows.
In each embodiment, the heating efficiency may be calculated only by the output current of the inverter circuit 25. In order to calculate the heating efficiency only by the output current, it is only necessary to determine the material of the cooking utensil during heating. As can be understood from the characteristic line of FIG. 6, the output current changes stepwise depending on the material of the cooked utensil. For this reason, if the output current is stored in the memory corresponding to the thermal power set by the user for each material, the material can be determined only by the output current, so the heating efficiency stored for each material can be increased. As a result, the heating efficiency can be calculated.

  The induction heating cooking apparatus provided only with the heating coil may be sufficient. There may be only one heating coil.

The enlarged plan view of the efficiency display part which shows the 1st Embodiment of this invention Vertical section of efficiency display Perspective view of cooking device Top view of cooking device Vertical side view of cooking device Characteristics chart of cooked utensils by material Electrical circuit configuration diagram FIG. 1 equivalent diagram showing a second embodiment of the present invention FIG. 1 equivalent view showing a third embodiment of the present invention FIG. 1 equivalent view showing a fourth embodiment of the present invention FIG. 1 equivalent view showing a fifth embodiment of the present invention FIG. 9 shows a sixth embodiment of the present invention, where (a) is an iron material, (b) is a clad material, (c) is nonmagnetic stainless steel, and (d) is a diagram corresponding to FIG. FIG. 1 equivalent view showing a seventh embodiment of the present invention FIG. 1 equivalent view showing an eighth embodiment of the present invention FIG. 9 shows a ninth embodiment of the present invention, wherein (a) and (b) are diagrams corresponding to FIG.

Explanation of symbols

  In the drawing, 8 is a heating coil, 25 is an inverter circuit, 38 is an input side current transformer (input current detection means), 41 is an input side voltage detector (input voltage detection means), 42 is an input voltage detection circuit, and 43 is an output. Side current transformer (output current detection means), 46 is a heating efficiency detection part (heating efficiency detection means), 47 is a display control part, 49 is an efficiency display part (display means), and 50 is a light emission display part.

Claims (9)

In an induction heating cooking apparatus that generates a high-frequency current by an inverter circuit and supplies the high-frequency current to a heating coil to inductively heat the cooked appliance,
Output current detection means for detecting the output current of the inverter circuit;
Heating efficiency detecting means for detecting heating efficiency based on the magnitude of the output current to the inverter circuit detected by the output current detecting means;
An induction heating cooking apparatus comprising display means for displaying the heating efficiency detected by the heating efficiency detection means. In the induction heating cooking apparatus according to claim 1,
Furthermore, an input current detecting means for detecting an input current of the inverter circuit is provided,
The induction heating cooking apparatus, wherein the heating efficiency detection means detects heating efficiency based on an input current and an output current to the inverter circuit detected by the input current detection means and the output current detection means, respectively. . In the induction heating cooking apparatus according to claim 1 or 2,
The heating efficiency detecting means detects the heating efficiency as a boiling time,
The induction heating cooking apparatus, wherein the display means displays the boiling time as heating efficiency. In the induction heating cooking apparatus according to claim 3,
The induction heating cooking apparatus, wherein the hot water boiling time is displayed according to the amount of water. In the induction heating cooking apparatus according to claim 1 or 2,
The induction heating cooking apparatus, wherein the display of the heating efficiency by the display means is performed by a symbol or a design. In the induction heating cooking apparatus according to any one of claims 1 to 4,
The induction heating cooking apparatus, wherein the display means displays a change in the heating efficiency from a predetermined time before to the present. In the induction heating cooking apparatus according to claim 1,
Furthermore, an output voltage detecting means for detecting the output voltage of the inverter circuit is provided,
The heating efficiency detection means detects instantaneous power from the output current detected by the output current detection means and the output voltage detected by the output voltage detection means,
The induction heating cooking apparatus, wherein the display means displays the instantaneous power detected by the heating efficiency detection means as the heating efficiency. In the induction heating cooking apparatus according to claim 2,
Furthermore, an input voltage detecting means for detecting an input voltage of the inverter circuit is provided,
The heating efficiency detection means detects instantaneous power from the input current detected by the input current detection means and the output voltage detected by the input voltage detection means,
The induction heating cooking apparatus, wherein the display means displays the instantaneous power detected by the heating efficiency detection means. In the induction heating cooking apparatus according to claim 7 or 8,
An integrating means for integrating the instantaneous power detected by the heating efficiency detecting means;
The induction heating cooking apparatus, wherein the display means displays integrated power.

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