JPH1050467A - Electromagnetic cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify without error the characteristic of a pan, and to prevent the breakdown of a transistor in an inverter circuit by measuring the output voltage until a heating coil starts the heating, and comparing the maximum output value with the set output value so as to use a lower value as the output value. SOLUTION: Output voltage for rectifying and smoothing circuits 2, 3 is measured for the time from a start key turning until a heating coil 4 starts the heating, and after the predetermined time has elapsed from the start of the heating, input current of the rectifying and smoothing circuits 2, 3 is measured. A measuring unit 10 measures the output voltage of an inverter circuit 5, and an output value selecting unit 11 selects the maximum output value of the heating coil 4 on the basis of the voltage value and the current value measured by the measuring unit 10, and the selected maximum output value and the output value, which has been previously and desirably set, are compared with each other so as to use a lower value as the output value of the heating coil 4. A signal control unit 12 controls the drive signal on the basis of the output value selected by the output value selecting unit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic cooker for heating by electromagnetic induction.

[0002]

2. Description of the Related Art Conventionally, in an electromagnetic cooker, when a start key is turned on, an inverter circuit is driven and an electromagnetic coil starts heating. Then, the input current of the rectifying / smoothing circuit during heating and the collector voltage of the transistor of the inverter circuit are measured to judge the characteristics of the pot, and the maximum output is controlled so as not to cause thermal breakdown of the transistor.

[0003]

In the above-mentioned conventional electromagnetic cooker, when the voltage of the commercial power supply fluctuates at the start of heating, the input current and the collector voltage change.
In some cases, the characteristics of the pot were misjudged. If the characteristics of the pot are incorrect, the heat loss of the transistor increases, and the heat loss sometimes destroys the transistor.

[0004] When an overvoltage is detected during the start of heating, the apparatus returns to the initial state. Therefore, even if the start key is turned on, the apparatus does not operate even when the start key is turned on. Further, since the microcomputer has a processing speed of several tens of ms, an overvoltage of several μs cannot be detected depending on timing.

Further, when detecting whether or not a pot is placed,
The inverter circuit is driven by a drive signal having one cycle of 500 ms on-time and 500 ms off-time. This cycle is the same as the cycle of the human heart rate. There was a case where a malfunction occurred due to misrecognition.

Further, when the output value of the heating coil is set by a key operation, the corresponding indicator light is turned on and notified by sound. However, when the setting reaches the upper limit or the lower limit, it is continuously performed. No sound was heard when the key was turned on.
In this case, particularly for visually impaired persons who rely on sound, if no sound is output, it is determined that the camera is broken, and this is not an appropriate display method.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to judge the characteristics of a pot without error even when the voltage of a commercial power supply fluctuates, and it is possible to reliably detect the occurrence of overvoltage. An object of the present invention is to provide an electromagnetic cooker in which a pacemaker does not malfunction even if a person using a pacemaker uses an electromagnetic cooker, and furthermore, even a visually impaired person can accurately set the output value of the heating coil. And

[0008]

An electromagnetic cooker according to the present invention comprises a rectifying and smoothing circuit for rectifying and smoothing a commercial power supply, and an inverter for applying an output voltage of the rectifying and smoothing circuit to a heating coil based on a drive signal input. The circuit and the output voltage of the rectifying / smoothing circuit are measured during the period from when the start key is turned on until the heating coil starts heating, and the input current of the rectifying / smoothing circuit is measured after a lapse of a predetermined time T1 from the start of heating. Measuring means for measuring the output voltage of the inverter circuit, and selecting a maximum output value of the heating coil based on the voltage value and the current value measured by the measuring means, and
An output value selecting unit that compares the selected maximum output value with an output value arbitrarily set in advance and sets a lower value as an output value of the heating coil, and an output value selected by the output value selecting unit. Signal control means for controlling the drive signal based on the signal.

A reference voltage set in advance is compared with an output voltage of the rectifying / smoothing circuit. When the measured voltage is higher than the reference voltage, the input of a drive signal to the inverter circuit is cut off and a voltage fluctuation is detected. A voltage fluctuation detection circuit for outputting a signal to the signal control means, wherein the signal control means stops control of the drive signal and starts time measurement when the voltage fluctuation detection signal is input, and the measurement time is set to a predetermined value. If the input of the voltage fluctuation detection signal is interrupted before the time T2 elapses, the control stop of the drive signal is released,
When the predetermined time T2 elapses before the input of the voltage fluctuation detection signal is cut off, the control of the drive signal is invalidated.

[0010] The signal control means controls when the heating coil starts heating so that the time input to the inverter circuit and the cutoff time do not become the same as the period of the human heart rate.

Further, according to the present invention, the output value of the heating coil is selected each time the output setting key is turned on, and it is determined whether the selected output value is the upper limit or the lower limit. When the output value judging means for outputting the setting invalid signal, the light is displayed in accordance with the output value selected by the output value judging means, and a preset sound is generated, and the setting invalid signal is inputted. And a display means for issuing a setting invalid alarm.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a circuit diagram of an electromagnetic cooker showing a first embodiment of the present invention, FIG. 2 is a flowchart showing an operation of the first embodiment, and FIG. 3 is a setting of a maximum output of a heating coil in the first embodiment. FIG. 4 is a flowchart showing an operation when an overvoltage is detected.

In FIG. 1, reference numeral 1 denotes a filter for removing harmonics, which is provided between a pair of capacitors C1 and C2 provided between lines of a commercial power supply, and provided between the pair of capacitors C1 and C2. It comprises a coil L1 connected to each line. 2 is a full-wave rectifier circuit, 3 is a smoothing circuit composed of a choke coil L2 and a capacitor C3, and R1 and R2 are resistors for dividing a rectified and smoothed voltage of a commercial power supply.
Enter 0. Reference numeral 5 denotes an inverter circuit which includes a transistor Tr1 which is turned on / off based on a drive signal (pulse) input, a diode D1 connected in parallel with the transistor Tr1, a resistor R3 and a Zener diode connected between the base and the emitter, respectively. Dz.

Tr2 is a transistor for controlling on / off of a drive signal based on an output signal (coil output) of a signal control section 12 described later, and has a base of 5V via a resistor R5.
The signal control unit 12 is connected to the power supply and the resistor R6
, And the collector is connected to the base side of the transistor Tr1 of the inverter circuit 5 via the resistor R4. Reference numeral 6 denotes a rectifier circuit for rectifying the detection current of the current detector CT, C4 denotes a smoothing capacitor for smoothing the rectified detection current, and the DC detection current is used as a current CT1 as a measuring unit 1
0 is input via the limiting resistor R8.

Reference numeral 7 denotes a voltage fluctuation detection circuit, which includes resistors R9 and R10 which divide a 5V power supply and use it as a reference voltage; resistors R11 and R12 which divide the voltage of the rectified and smoothed commercial power supply; At the connection point of R12, the non-inverting input terminal is connected to the connection point of the resistors R9 and R10, and the output terminal is connected to the base side of the transistor Tr1 of the inverter circuit 5 via the resistor R14 and the diode D2. It comprises a comparator IC connected to the signal control unit 12 via the limiting resistor R15, and a capacitor C5 connected in parallel with the resistor R12.
When the voltage V1 of the commercial power supply divided in step 2 is equal to or higher than the reference voltage, the output (voltage fluctuation detection signal) is inverted to a low level and the input of the drive signal to the inverter circuit 5 is cut off.

R16 and R17 are resistors for dividing the collector voltage of the transistor Tr1 of the inverter circuit 5, and this divided voltage is input to the measuring section 10 as the collector voltage VCE via the limiting resistor R18. Reference numeral 8 denotes a buzzer circuit, a transistor Tr3 having a base connected to the signal control unit 12 via a limiting resistor R20, and one end connected to the transistor Tr3.
And a resistor R19 having one end connected to the buzzer Bz and the other end connected to the 5V power supply of the voltage fluctuation detection circuit 7.

Reference numeral 9 denotes a control unit, which comprises, for example, a microcomputer. The voltage VAC of the commercial power source divided by the resistors R1 and R2 is used from when a start key (not shown) is turned on until the heating coil 4 starts heating. Is measured, a current CT1 detected by the current detector CT is measured after a lapse of a predetermined time T1, for example, 500 ms from the start of heating, and R16 and R17 are measured.
And the maximum output value of the heating coil 4 is selected based on the voltage VAC measured by the measuring unit 10, the current CT1, and the collector voltage VCE (see FIG. 2). The output value selector 11 compares the selected maximum output value with an output value set manually in advance, and determines the lower value as the output value of the heating coil 4. The drive signal is controlled based on the selected output value, and when the output of the voltage fluctuation detection circuit 7 becomes low level, the control of the drive signal is temporarily stopped and the measurement of time is started. When the output is inverted from the low level to the high level before elapse of a predetermined time T3, for example, 1 s, the control stop of the drive signal is released, and 1 s before the output is inverted from the low level to the high level.
When the time has elapsed, the signal control unit 12 stops the control of the drive signal and resets the drive signal to an initial state.

When selecting the maximum output value, the output value selecting section 11 determines whether the measured collector voltage VCE is equal to or less than 400 V or less than 400 V, as shown in FIG. For example, when the collector voltage VCE is 400 V or less, it is determined whether the current CT1 applies to any of the A, B, and C stages. When the current CT1 is determined to be the B stage, the maximum output value is selected based on the voltage VAC. Then, the resulting output value is output to the signal control unit 12.

When the collector voltage VCE and the current CT1 are both in the D stage, it is determined that an appropriate pot is not placed on the heating coil 4 and a "pot sign" is selected, and a heating stop signal is issued. The signal is output to the signal controller 12 and all the measured values are cleared. Then, the voltage VAC measured by the measuring unit 10 is input again, and then the collector voltage VCE and the current CT1 are input, and the selection of the maximum output value is started. This operation is repeated every time a "nabe sign" is selected. If the operation is continuously performed for one minute or more, the effect is displayed on a display unit (not shown) and the start key is turned off. To end.

The operation of the electromagnetic cooker configured as described above will be described with reference to the flowcharts of FIGS.
First, the operation when setting the output value of the heating coil will be described based on the flowchart of FIG.

When the start key is turned on (S1), the signal control unit 12 sets the coil output to low level to input a drive signal to the inverter circuit 5, and the measuring unit 10
During the period from when the start key is turned on until the heating coil 4 starts heating, the voltage VAC of the commercial power source divided by the resistors R1 and R2 is measured (S2), and the time measurement is started after the heating is started. It is determined whether T1 (500 ms) has elapsed (S3). On the other hand, when the heating coil starts heating, the signal control unit 12 inputs a drive signal having a pulse width of 15 μs to the inverter circuit 5 for 500 ms, and cuts off the drive signal input for 500 ms after the lapse of the time. Is repeatedly executed. When the measuring section 10 confirms that the measurement time has passed 500 ms, it measures the current CT1 through the current detector CT (S4), and then measures the collector voltage VCE divided by the resistors R16 and R17. Hold (S
5).

Voltage VAC, current CT1 and collector voltage V
When the CE is measured, the output value selection unit 11 starts selecting the maximum output value based on these measured values (S6). At this time, it is determined whether the “nabe sign” has been selected (S
7) When "pan sign" is selected, it is determined whether one minute has elapsed since the start of heating (S13). If one minute has elapsed, the start key is turned off and this operation is terminated. (S16) If one minute has not elapsed, a heating stop signal is output to the signal controller 12, and the held voltage VAC, current CT1 and collector voltage VCE are cleared (S14, S15). Then, the voltage VAC measured by the measuring unit 10 is input again (S2), and after 500 ms has elapsed, the collector voltage VCE and the current CT1 are input, and selection of the maximum output value is started (S3 to S6).

When the optimum maximum output value is selected while repeating this operation, the output value selection section 11 compares the selected maximum output value with an output value set manually in advance (S8). When the maximum output value is lower, the value is set as the output value of the heating coil 4 (S9). When the output value set manually is lower, the output value is set to the heating coil 4.
(S10), and outputs the result to the signal control unit 12. The signal control unit 12 includes the output value selection unit 1
The drive signal is controlled via the transistor Tr2 so that the output value selected in Step 1 is obtained (S11), and is input to the inverter circuit 5. At this time, the output value selection unit 11
Determines whether the manual output value has been changed (S12). If the manual output value has been changed, the process returns to step 8 to compare with the maximum output value. If the manual output value has not been changed, This is notified to the signal control unit 12.

Next, the operation when the power supply voltage fluctuates during the heating control based on the selected output value will be described with reference to the flowchart of FIG. During the heating control (S21), the voltage fluctuation detecting circuit 7 inputs the divided voltage V1 of the commercial power supply and compares it with the reference voltage (S22, S23). When the voltage V1 is, for example, 190 V or more, Inverts the output level to the low level and cuts off the input of the drive signal controlled by the signal control unit 12 to the inverter circuit 5 (S24). The signal control unit 12 includes the voltage fluctuation detection circuit 7
Is inverted to a low level, the level of the coil output is inverted to a high level to turn off the transistor Tr2,
The control of the drive signal is temporarily stopped, and time measurement is started (S25, S26). Then, it is determined whether or not the measurement time has elapsed 1s (S27). If the measurement time has elapsed 1s, the process proceeds to step 30, but if the measurement time has not elapsed 1s, the output of the voltage fluctuation detection circuit 7 becomes high. It is determined whether the level has been inverted (S2
8). If the output is not inverted, the flow returns to step 27 to check again the passage of time. If it is confirmed that the output has been inverted to the high level, the temporary stop of heating is released (S29). At this time, the voltage fluctuation detection circuit 7
The voltage V1 is detected and comparison with the reference voltage is started (S2).
2).

When the signal control section 12 confirms in step 27 that the measurement time has elapsed 1s, the signal control section 12 turns on the transistor Tr3 of the buzzer circuit 8 to sound the buzzer Bz (S30), and sets the selected output value to the selected value. Based on this, the heating control is stopped, that is, the coil output is inverted to a high level to turn off the drive signal (S31), and then this control is returned to the initial state and terminated (S32).

In the first embodiment, the voltage VAC of the commercial power supply is measured between the time the start key is turned on and the time the heating coil 4 starts heating, and the current of the current detector CT is measured 500 ms after the start of heating. CT1 and collector voltage V
CE is measured, a maximum output value is selected based on these measured values, and the maximum output value is compared with an output value set manually in advance, and the lower value is used as the output of the heating coil 4. The value can be specified so that the characteristics of the pot can be specified without error even if a voltage fluctuation occurs in the commercial power supply, and furthermore, the specification of the pot characteristics is accurate, thereby preventing the transistor Tr1 from being destroyed due to heat loss. effective.

When an overvoltage of several tens of μs occurs, the voltage fluctuation detection circuit 7 inverts the output to a low level and cuts off the input of the drive signal to the inverter circuit 5,
When the signal control unit 12 recognizes the output, the coil output is set to the high level to stop heating, and at the same time, the time is measured. Before the time T2 elapses, the output of the voltage fluctuation detection circuit 7 is set to the high level. The heating control is released from the halt when inverted, and the heating control is returned to the initial state when the measurement time has elapsed time T2 before the output of the voltage fluctuation detecting circuit 7 is inverted to the high level. Conventionally, dozens
There is an effect that it is not possible to cope only with overvoltage of ms or more.

Embodiment 2 FIG. In the above embodiment, when the heating coil 4 starts heating, the time of the drive signal input to the inverter circuit 5 is set to 500 ms, the cutoff time is set to 500 ms, and this is repeated. This may be repeated by setting 2 s and the cutoff time to 1 s.

FIG. 5 is a flowchart for explaining the generation of a drive signal at the time of setting the output value of the heating coil. When the heating coil 4 starts heating after the start key is turned on, the signal control unit 12 outputs the drive signal. Input to the inverter circuit 5 for 2 s, cut off for 1 s after the lapse of the time,
I try to repeat this. The control of the drive signal is for determining whether or not the pan is placed on the heating coil 4, and when the current CT1 of the current detector CT is 4
When the value is A or more, it is determined that the pot is placed. Next, the operation will be described. When the heating coil 4 starts heating after the start key is turned on (S41), the signal control unit 12 sets the coil output level to low level and sets the transistor Tr2 to the low level.
Is turned off (S42), and the drive signal is supplied to the inverter circuit 5
Input. At this time, measurement of time is started, and it is determined whether the current CT1 of the current detector CT is 4 A or more (S43, S44). If the detected current CT1 is less than 4 A, it is determined whether or not the measurement time has elapsed 2s (S45). If the measurement time has elapsed 2s, the process proceeds to step 46, but if not, the process proceeds to step 4.
Returning to 4, it is determined again whether the detected current CT1 is 4 A or more. These steps 44 and 45 are repeated until the detection current CT1 becomes 4 A or more, or the measurement time is 2 seconds.
It is done until the elapse.

In step 45, when the measurement time has elapsed 2s, the coil output is inverted from the low level to the high level to turn on the transistor Tr2 (S46), and the input of the drive signal to the inverter circuit 5 is cut off to perform heating. It stops (S47) and waits for 1 second for that state (S48). Then, when 1 s has elapsed, the flow returns to step 42 to invert the level of the coil output from the high level to the low level, and start time measurement (S43). By repeating this operation, the drive signal is generated for every 2 seconds by the drive circuit 5 every 1 second.
Is input to When the detection signal CT1 becomes 4 A or more due to the input of the drive signal, the signal control unit 12 clears the measurement time (S49), and drives based on the output value of the heating coil selected by the output value selection unit 11. The control of the signal is started (S50), and this operation ends.

In the second embodiment, at the time of detecting a pot after the start of heating, a drive signal is input to the inverter circuit 5 for 2 seconds, then cut off for 1 second, and this is repeated, so that the implantable cardiac pacemaker is repeated. There is an effect that the pacemaker does not malfunction even if the person holding the electronic cooker uses this electromagnetic cooker.

Embodiment 3 FIG. 6 is a block diagram showing a third embodiment of the present invention, and FIG. 7 is a flowchart showing an operation in the third embodiment. Note that the same or corresponding parts as those in the first embodiment described with reference to FIG.

In the figure, 13 is a low output setting key, 14
Is a high output setting key, 15 is an output value judging unit, for example, provided with a microcomputer.
Each time the switch 14 is turned on, the output value of the heating coil is selected and output to that effect to the output value selection unit 11, and it is determined whether the selected output value is the upper limit or the lower limit. In the case of, a setting invalid signal is output.

Reference numeral 16 denotes a display unit which lights the lighting unit 16a and emits a sound in accordance with the output value selected by the output value judgment unit 1. For example, as the lighting section 16a lights up in the "strong" direction, a "pip" sound is generated for 0.2s, and as the lighting section 16a lights up in the "throat" direction, a "pip" sound is generated for 0.2s. Occurs. When the “high” lighting section 16a is lit by the input of the setting invalid signal, for example,
A beep sound is generated for 0.5 s, and a "poop" sound is generated for 0.5 s, for example, when the lighting section 16a of "throat fire" is turned on by the input of the setting invalid signal.

Next, the operation will be described with reference to the flowchart of FIG. When the output setting key is turned on (S61), the output value determining unit 15 determines whether the output setting key is the high output setting key 14 (S62). In the case of the high output setting key 14, it is determined whether or not the current setting is "strong" (S63). If the current setting is "strong", a setting invalidation signal is output (S6).
6) If the setting is not “strong”, “beep” for 0.2s
Is generated on the display unit 16 and the lighting unit 16
The lighting of a is increased by one step (S64, S65), and the process returns to step 61. If the current setting is "strong", a setting invalidation signal is output to the display unit 16 to generate a "beep" sound for 0.5 seconds (S66, S67), and the process returns to step 61.

The output value judging section 15 determines in step 62
When it is confirmed that the low output setting key is turned on, it is determined whether or not the current setting is “throttle” (S68), and if the current setting is not “throttle”, a “push” sound is displayed for 0.2 seconds. In step S69, the lighting of the lighting unit 16a is lowered by one step (S69, S70).
Return to If the current setting is “Torui”, a setting invalid signal is output to the display unit 16 to generate a “poo” sound for 0.5 seconds (S71, S72), and the process returns to step 61.

In the third embodiment, when the upper limit “strong” is selected by turning on the high output setting key,
Conversely, different sounds are generated when the lower limit "Torohi" is selected by turning on the low output setting key, so that even a visually impaired person can recognize that the setting is invalid.

[0038]

As described above, according to the present invention, the output voltage of the rectifying / smoothing circuit is measured between the time when the start key is turned on and the time when the heating coil starts heating, and after a lapse of a predetermined time T1 from the start of heating. Measure the input current of the rectifying and smoothing circuit and the output voltage of the inverter circuit, select the maximum output value based on these measured values, and compare this maximum output value with an output value set arbitrarily in advance. Since the lower value is used as the output value of the heating coil, the characteristics of the pan can be specified without error even if the voltage fluctuates in the commercial power supply. Therefore, there is an effect that the breakdown of the transistor of the inverter circuit due to the above can be prevented.

When an overvoltage occurs, the voltage fluctuation detection circuit cuts off the input of the drive signal to the inverter circuit and outputs a voltage fluctuation detection signal to the signal control means.
The signal control means stops the control of the drive signal when the voltage fluctuation detection signal is input and starts measuring the time, and when the input of the voltage fluctuation detection signal is interrupted before the measurement time elapses a predetermined time T2. Releases the control stop of the drive signal and disables the control of the drive signal when the measurement time elapses a predetermined time T2 before the input of the voltage fluctuation detection signal is cut off. It is possible to reliably detect any of ms and several μs and protect the inverter circuit, and furthermore, there is an effect that the operation does not stop even if the start key is turned on when overvoltage is applied.

Further, when the heating coil starts heating,
Since the time and the cutoff time of the drive signal input to the inverter circuit are controlled so as not to be the same as the period of the human heart rate, there is an effect that the pacemaker does not stop by mistake.

Further, when the upper limit or the lower limit of the output value is set by setting the heating power setting key, an invalid warning is issued, so that the visually impaired person can recognize the state.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an electromagnetic cooker according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the first embodiment.

FIG. 3 is a diagram for explaining setting of a maximum output of a heating coil according to the first embodiment.

FIG. 4 is a flowchart illustrating an operation when an overvoltage is detected.

FIG. 5 is a flowchart illustrating generation of a drive signal when an output value of a heating coil is set.

FIG. 6 is a block diagram showing a third embodiment of the present invention.

FIG. 7 is a flowchart showing an operation in the third embodiment.

[Explanation of symbols]

1 filter, 2 full-wave rectifier circuit, 3 smoothing circuit, 4
Heating coil, 5 inverter circuit, 7 voltage fluctuation detection circuit, 8 buzzer circuit, 9 control section, 10 measuring section, 11
Output value selector, 12 signal controller.

Claims (4)

[Claims] 1. A rectifying and smoothing circuit for rectifying and smoothing a commercial power supply, an inverter circuit for applying an output voltage of the rectifying and smoothing circuit to a heating coil based on an input of a drive signal, and a heating coil after a start key is turned on. Measuring means for measuring the output voltage of the rectifying / smoothing circuit until the start of heating, measuring the input current of the rectifying / smoothing circuit after a lapse of a predetermined time T1 from the start of heating, and measuring the output voltage of the inverter circuit; A maximum output value of the heating coil is selected based on the voltage value and the current value measured by the measuring unit, and the selected maximum output value is compared with an output value arbitrarily set in advance to obtain a value. Output value selection means for setting the lower one as the output value of the heating coil; and signal control means for controlling the drive signal based on the output value selected by the output value selection means. An electromagnetic cooker, characterized in that: 2. A method for comparing a preset reference voltage with an output voltage of the rectifying / smoothing circuit, and when a measured voltage is higher than the reference voltage, interrupts a drive signal input to the inverter circuit and detects a voltage fluctuation. A voltage fluctuation detection circuit for outputting a signal to the signal control means, wherein the signal control means stops control of the drive signal and starts time measurement when the voltage fluctuation detection signal is input, and the measurement time is set to a predetermined value. When the input of the voltage fluctuation detection signal is interrupted before the time T2 elapses, the control stop of the drive signal is released, and when the predetermined time T2 elapses before the input of the voltage fluctuation detection signal is interrupted, The electromagnetic cooker according to claim 1, wherein control of the drive signal is invalidated. 3. The signal control means according to claim 1, wherein when the heating coil starts heating, the time inputted to the inverter circuit and the cutoff time are controlled so as not to be the same as the period of the human heart rate. Item 3. The electromagnetic cooker according to Item 1 or 2. 4. Each time the output setting key is turned on, the output value of the heating coil is selected, and it is determined whether the selected output value is the upper limit or the lower limit. If the output value is the upper limit or the lower limit, the setting is invalid. Output value determining means for outputting a signal; lighting and displaying according to the output value selected by the output value determining means; generating a preset sound; and invalidating the setting when the setting invalidation signal is input. 4. An electromagnetic cooker according to claim 1, further comprising a display means for issuing a warning.