JP4407438B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker that induction-heats a pan or the like with a magnetic flux of a heating coil by an inverter circuit.

  Conventionally, this type of induction heating cooker has a full-wave rectification of the commercial power supply and a surge voltage detection circuit with a differential voltage configuration and resistance voltage detection at both ends, and detects the steady power supply voltage and the voltage caused by the surge. When an abnormal voltage is detected, the driving operation of the switching element is stopped (for example, see Patent Document 1).

FIG. 5 shows a conventional induction heating cooker described in Patent Document 1. As shown in FIG. Hereinafter, a conventional example will be described with reference to FIG. The diode bridge 102 performs full-wave rectification on the commercial power supply 101, and the smoothing capacitor 103 smoothes the commercial power supply 101 rectified by the diode bridge 102 into a DC power supply. The inverter circuit 104 includes a heating coil 105, a resonant capacitor 106, and a switching element 107 made of IGBT or the like. The drive control means 108 drives and controls the switching element 107, passes a high-frequency current through the heating coil 105, and turns the switching element 107 on and off at a high frequency so as to heat a pan or the like (not shown) as an object to be heated. The surge detecting means 109 detects the voltage of the DC power source smoothed from the commercial power source 101 and comprises a differentiation circuit composed of a capacitor and a resistor. When a surge is applied above the steady voltage, a high voltage is generated in the differentiation circuit. Is output. The voltage comparison unit 110 compares the value detected by the surge detection unit 109 with a predetermined value, and outputs a signal to the drive stop unit 112 when a voltage equal to or higher than the predetermined value is input, and the switching element 107 by the drive control unit 108. The drive was stopped.
Japanese Patent No. 3249294

  However, in the above-described conventional configuration, it is not possible to distinguish between a case where the power supply voltage changes only once due to lightning, an instantaneous power failure, or the like, and a substantially periodic harmonic external noise generated by other devices. Such substantially periodic external noise does not have as much energy as a lightning surge, and even when the driving of the switching element 107 is not stopped, the driving stop means 112 works and heating cooking may stop. . At this time, if the external noise at a level where the device stops is periodic, there is a problem that the device cannot be used while the external noise is superimposed on the commercial power source.

  An object of this invention is to provide the induction heating cooking appliance which reduced the situation where heating cannot be used carelessly and it cannot be used by switching the voltage detection level of a commercial power source.

In order to solve the conventional problem, the induction heating cooker of the present invention compares a surge detection means for detecting a surge or the like superimposed on a commercial power supply, and a voltage detected by the surge detection means and a surge voltage threshold. Voltage comparison means, a drive stop means for stopping the driving of the switching element when the voltage comparison means determines that the detection voltage by the surge detection means is higher than a surge voltage threshold, and the number of stops by the drive stop means. And a voltage switching means for switching the detection voltage level of the power supply voltage detection means, wherein the voltage switching means is configured to detect the surge detection means when the number of stops exceeds a predetermined number within a predetermined time. The detection voltage level is switched to lower .

Thus, if the repeated stopping predetermined number of times or more, the voltage switching example means it is different from the abrupt change of sporadic lightning surges and momentary power failure and the power supply voltage of the power failure recovery that occurs, the surge detection means detecting the voltage level and it is possible to reduce the like can not be heated by periodic external noise or the like in Rukoto lowered to a level that does not stop driving.

Further, a power supply voltage detecting means for detecting the voltage of the commercial power supply, a surge detecting means for detecting a surge or the like superimposed on the commercial power supply, and a voltage comparison for comparing the voltage detected by the surge detecting means with a surge voltage threshold value And a drive stop means for stopping the driving of the switching element when the voltage comparison means determines that the detection voltage by the surge detection means is higher than a surge voltage threshold, and a stop for measuring the number of stops by the drive stop means Frequency measurement means and voltage switching means for switching the detection voltage level of the power supply voltage detection means, wherein the voltage switching means has a number of stops within a predetermined time equal to or greater than a predetermined number of times, and the power supply voltage detection means If the detected voltage is less than the driving voltage allowed value, but to switch to lower the detection level of said surge detecting means.

Thus, a power supply voltage variation sporadically generated by lightning or momentary power failure or the like, since the case of substantially periodically external noise generated by switching the voltage detection level, to reduce the situation that can not be used to stop heating unnecessary meaning be able to. In addition, since the voltage detection level is switched only when the drive voltage is less than or equal to the drive voltage permission value, the breakdown prevention level of the device is not lowered so much.

Further, surge detection means for detecting a surge or the like superimposed on a commercial power supply, voltage comparison means for comparing a voltage detected by the surge detection means and a surge voltage threshold, and detection by the surge detection means by the voltage comparison means A drive stop means for stopping driving of the switching element when it is determined that the voltage is higher than a surge voltage threshold; a stop count measuring means for measuring the number of stops by the drive stop means; and a surge voltage threshold of the voltage comparison means. Comparison voltage switching means for switching , and the voltage switching means switches the surge voltage threshold to a higher voltage when the number of stops within a predetermined time is equal to or greater than a predetermined number.

As a result, the voltage level compared by the comparison threshold switching means is switched to a high voltage in the case of the power supply voltage fluctuation that occurs only once due to lightning or instantaneous power failure and the case of external noise that occurs substantially periodically, it is possible to reduce the situation that can not be used to stop heating unnecessary attention. Further, the voltage input to the voltage comparing means are pressed later to a small signal can be realized with an inexpensive configuration.

Further, a power supply voltage detecting means for detecting the voltage of the commercial power supply, a surge detecting means for detecting a surge or the like superimposed on the commercial power supply, and a voltage comparison for comparing the voltage detected by the surge detecting means with a surge voltage threshold value And a drive stop means for stopping the driving of the switching element when the voltage comparison means determines that the detection voltage by the surge detection means is higher than a surge voltage threshold, and a stop for measuring the number of stops by the drive stop means a number measuring means, before a comparison threshold switching means for switching the hexa over di voltage threshold, the comparison threshold value switching means is a number of stops within a predetermined time a predetermined number of times or more, and at the power supply voltage detection means When the detected voltage is less than or equal to the drive voltage permission value , the surge voltage threshold is switched to a higher voltage .

As a result, the voltage level compared by the comparison threshold switching means is switched to a high voltage in the case of the power supply voltage fluctuation that occurs only once due to lightning or instantaneous power failure and the case of external noise that occurs substantially periodically, it is possible to reduce the situation that can not be used to stop heating unnecessary attention. Further, the voltage input to the voltage comparing means are pressed later to a small signal can be realized with an inexpensive configuration. In addition, since the voltage detection level is switched only when the drive voltage is less than or equal to the drive voltage permission value, the breakdown prevention level of the device is not lowered so much.

Induction heating cooker of the present invention, since the switch and the power supply voltage fluctuation sporadically generated by lightning or momentary power failure or the like, substantially periodically voltage detection level in the case of external noise that occurs less affected, the unnecessary meaning It is possible to reduce the situation where the heating is stopped and cannot be used.

The first invention includes an inverter circuit including a heating coil, a resonant capacitor, and a switching element, drive control means for driving and controlling the switching element of the inverter circuit, and surge detection means for detecting a surge superimposed on a commercial power source. And a voltage comparison means for comparing the voltage detected by the surge detection means with a surge voltage threshold, and the switching element when the voltage comparison means determines that the detection voltage by the surge detection means is higher than the surge voltage threshold. Drive stop means for stopping the driving of the motor, stop frequency measuring means for measuring the number of stops by the drive stop means, and voltage switching means for switching the detection voltage level of the surge detection means, wherein the voltage switching means If the number of stop in time is equal to or more than the predetermined number of times, the detection voltage level of the surge detection means By switching to the gel so, switches the level of the power supply voltage variation sporadically generated by lightning or momentary power failure or the like, the voltage detection level to a level that does not stop the drive in the case of substantially periodically external noise generated Therefore, it is possible to reduce the situation where the heating is inadvertently stopped and cannot be used.

The second invention includes an inverter circuit including a heating coil, a resonant capacitor, and a switching element, drive control means for driving and controlling the switching element of the inverter circuit, power supply voltage detection means for detecting the voltage of a commercial power supply, A surge detection means for detecting a surge or the like superimposed on a commercial power source, a voltage comparison means for comparing a voltage detected by the surge detection means with a surge voltage threshold, and a voltage detected by the surge detection means by the voltage comparison means. Switching between the drive stop means for stopping the driving of the switching element, the stop count measuring means for measuring the number of stops by the drive stop means, and the detection voltage level of the surge detection means when judged to be higher than the surge voltage threshold and a voltage switching means, said voltage switching means, the number of stops is a predetermined number or more within a predetermined time period In, and, when the voltage detected by the supply voltage detecting means is less than the driving voltage allowed value, by switching the detection level of said surge detecting means, sporadic supply voltage variation caused by lightning or momentary power failure or the like If so switched as in the case of the external noise that occurs substantially periodically lowering the voltage detection level, it is possible to reduce the situation that can not be used to stop heating unnecessary attention. In addition, since the voltage detection level is switched only when the drive voltage is less than or equal to the drive voltage permission value, the breakdown prevention level of the device is not lowered so much.

In the third invention, in particular, the switching element is driven by the drive control means in a state where the detection level of the surge detection means is switched by the voltage switching means of the first or second invention, and the drive by the drive stop means for a predetermined time. When the operation is not stopped, the detection level switched by the voltage switching means is returned to the initial level. When the external noise is reduced, the level can be returned to the same level of breakdown prevention as usual. Can keep protection against.

According to a fourth aspect of the present invention, there is provided an inverter circuit including a heating coil, a resonant capacitor, and a switching element, drive control means for driving and controlling the switching element of the inverter circuit, and surge detection means for detecting a surge superimposed on a commercial power source. And a voltage comparison means for comparing the voltage detected by the surge detection means with a surge voltage threshold, and the switching element when the voltage comparison means determines that the detection voltage by the surge detection means is higher than the surge voltage threshold. and drive stop means for stopping the driving of a number of stops measuring means for measuring the number of times stopping by said drive stopping means, before a comparison threshold switching means for switching the hexa over di voltage threshold, the comparison threshold value switching means, If the number of stops within a predetermined time is equal to or more than the predetermined number of times, even switching the surge voltage threshold to a high voltage , And the power supply voltage fluctuation sporadically generated by lightning or momentary power failure or the like, the voltage level so switched that is compared by the comparator threshold switching means in the case of substantially periodically external noise occurs, the unnecessary meaning It is possible to reduce the situation where the heating is stopped and cannot be used. Further, the voltage input to the voltage comparing means are pressed later to a small signal can be realized with an inexpensive configuration.

According to a fifth aspect of the present invention, there is provided an inverter circuit including a heating coil, a resonant capacitor, and a switching element, drive control means for driving and controlling the switching element of the inverter circuit, power supply voltage detection means for detecting a commercial power supply voltage, A surge detection means for detecting a surge or the like superimposed on a commercial power source, a voltage comparison means for comparing a voltage detected by the surge detection means with a surge voltage threshold, and a voltage detected by the surge detection means by the voltage comparison means. comparison of switching a drive stop means for stopping the driving of the switching element when it is determined that higher than the surge voltage threshold, the number of stops measuring means for measuring the number of times stopping by said drive stopping means, the pre-hexa over di voltage threshold and a threshold value switching means, said comparison threshold value switching means is a number of stops within a predetermined time a predetermined number of times or more, or , When the voltage detected by the supply voltage detecting means or less driving voltage allowed value, which switches the surge voltage threshold to a higher voltage, and the power supply voltage fluctuation generated sporadically by lightning or momentary power failure or the like, since the voltage level of the are compared by comparing the threshold switching means in the case of substantially periodically external noise to be generated off switched, it is possible to reduce the situation that can not be used to stop heating unnecessary attention. Further, the voltage input to the voltage comparing means are pressed later to a small signal can be realized with an inexpensive configuration. In addition, since the voltage detection level is switched only when the drive voltage is less than or equal to the drive voltage permission value, the breakdown prevention level of the device is not lowered so much.

A sixth invention is particularly, the invention of the fourth or fifth, comparison threshold value switching means switching element is driven by the drive control means by Lisa over state di voltage threshold is switched to a predetermined time drive stop means If the drive stop is not performed by, which returns a surge voltage threshold value is switched by the comparator threshold switching means in the initial, because reversible usually the same fracture prevention level and if the external noise has been reduced, Furthermore, protection against a single surge can be maintained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of an induction heating cooker according to the first embodiment of the present invention. This will be described below with reference to FIG.

  The diode bridge 2 performs full-wave rectification on the commercial power supply 1, and the smoothing capacitor 3 smoothes the commercial power supply 1 rectified by the diode bridge 2 to obtain a DC power supply. The inverter circuit 4 includes a heating coil 5, a resonant capacitor 6, and a switching element 7 made of IGBT or the like. The drive control means 8 drives and controls the switching element 7, passes a high-frequency current through the heating coil 5, and turns the switching element 7 on and off at a high frequency so as to heat a pan or the like (not shown) as an object to be heated. The surge detection means 9 detects a surge superimposed on the commercial power source 1 and outputs Vs which is a divided voltage of Vin. When the Vin voltage jumps suddenly, such as a surge, a differential circuit composed of C1 and R2 Can capture the change. The voltage comparison means 10 compares the reference Vref voltage with the output voltage Vs from the surge detection means 9, and sends a stop signal to the drive stop means 12 if Vs> Vref. The drive stop means 12 receives the signal from the voltage comparison means 10 and stops the control of the switching element 7 by the drive control means 8. The stop count measuring means 11 measures the number of times the operation is stopped by the drive stop means 12 in a predetermined time, and if it is equal to or greater than the predetermined number, the voltage switching means 13 such as a relay switches the connection of C2.

  Normally, the connection of C2 by the voltage switching means 13 is ON, that is, C1 and C2 are connected in parallel, and the differentiation becomes easier to work by increasing the capacity of the capacitor constituting the differentiation circuit of the surge detection means 9. This makes it easy to detect fluctuations in the power source Vin due to a surge that occurs once.

  Here, for example, when the same commercial power source 1 is connected to another switching power source device, a capacitor input device such as an air conditioner, or a phase control device such as a vacuum cleaner or a bag, the input waveform of the commercial power source 1 is displayed. When periodic noise occurs, the differentiation circuit of the surge detection means 9 detects the noise, and Vs periodically increases. As a result, Vref of the voltage comparison means 10 (for example, equivalent to the superimposed voltage 350V). ) As described above, for example, the superimposed voltage may be approximately 360V. In this case, the heating is stopped by the drive stopping means 12 almost in synchronization with the external noise. The stop count measuring means 11 measures the drive stop count for a predetermined time (for example, 1 minute), and if the drive stop count is equal to or greater than the predetermined count (for example, 10 count or more), the voltage switching means 13 disconnects C2. . As a result, the capacitance of the capacitor constituting the differentiating circuit is reduced, so that the action of the differentiation is suppressed. That is, even at the same voltage fluctuation level, the voltage Vs output by the surge detection means 9 is a low voltage. Thereby, the case where heating stops and becomes unusable due to periodic external noise or the like different from surge can be reduced.

  Furthermore, if periodic noise is superimposed due to the influence of other equipment, the use of the other equipment may be terminated, so heating is continued with the capacitor C2 disconnected by the voltage switching means 13. In this case, the voltage switching means 13 connects the capacitor C2 after a predetermined time (approximately 15 minutes, for example, in a range that does not affect cooking). As a result, when the external noise that stops the heating is already removed, the operation level of the original differential is obtained, and the device can be protected more safely against a single surge or the like. Further, even when the heating is once stopped by the user, the initial state in which the capacitor C2 is connected is returned. As a result, the surge detection level is lowered only when periodic external noise is superimposed on the commercial power supply 1 and heating is not possible. In other cases, the surge can be detected to keep the device protected. Is possible.

  In the present embodiment, the voltage switching means is the switching of capacitors connected in parallel, but the same effect can be obtained by connecting capacitors in series or switching the voltage dividing ratio of resistors.

  In this embodiment, the inverter circuit is a monolithic voltage resonance inverter. However, in a full-bridge or half-bridge inverter, the same configuration can be used as a protection circuit against a surge superimposed on the commercial power source 1. Similar effects can be obtained.

(Embodiment 2)
FIG. 2 is a configuration diagram of the induction heating cooker according to the second embodiment of the present invention. In addition, the same number is provided about the structure shown in Embodiment 1, and only a different structure is demonstrated.

  A power supply voltage detection means 14 constituted by resistance voltage division, a band-pass filter 15 that passes about 100 Hz, which is approximately twice the frequency of the commercial power supply 1, and a logic comparator 16 are provided to the output. Vin is detected, and further, the voltage Vin of the commercial power source 1 is detected through the band-pass filter 15. Both of the voltage range in which Vin does not cause a problem even if the normal device is operated in the logical comparator 16 and the switching condition that the number of times of driving stop by the stop number measuring means 11 is periodic are satisfied. In such a case, the voltage switching means 13 switches the connection of the capacitor C2.

  As a result, the surge detection level is switched only in the voltage range where there is no problem even if the normal device is operated, so that the breakdown prevention level of the device is not lowered much.

  In the present embodiment, the voltage switching means 13 is switched between capacitors connected in parallel, but the same effect can be obtained by connecting capacitors in series or switching the voltage dividing ratio of resistors.

  In this embodiment, the inverter circuit is a monolithic voltage resonance inverter. However, in a full-bridge or half-bridge inverter, the same configuration can be used as a protection circuit against a surge superimposed on the commercial power source 1. Similar effects can be obtained.

(Embodiment 3)
FIG. 3 is a configuration diagram of an induction heating cooker according to the third embodiment of the present invention. This will be described below with reference to FIG.

  The diode bridge 2 performs full-wave rectification on the commercial power supply 1, and the smoothing capacitor 3 smoothes the commercial power supply 1 rectified by the diode bridge 2 to obtain a DC power supply. The inverter circuit 4 includes a heating coil 5, a resonant capacitor 6, and a switching element 7 made of IGBT or the like. The drive control means 8 drives and controls the switching element 7, passes a high-frequency current through the heating coil 5, and turns the switching element 7 on and off at a high frequency so as to heat a pan or the like (not shown) as an object to be heated. The surge detection means 9 detects a surge superimposed on the commercial power source 1 and outputs Vs which is a divided voltage of Vin. When the Vin voltage jumps suddenly such as a surge, the differential composed of C1 and R2 The change can be caught by the circuit. The voltage comparison means 10 compares the reference Vref voltage with the output voltage Vs from the surge detection means 9, and sends a stop signal to the drive stop means 12 if Vs> Vref. The drive stop means 12 receives the signal from the voltage comparison means 10 and stops the control of the switching element 7 by the drive control means 8. The stop count measuring means 11 measures the number of times the operation has been stopped by the drive stop means 12 in a predetermined time.

  The connection of R6 by the normal comparison threshold switching means 17 is off, that is, Vref is determined only by the partial pressure of R4 and R5. Here, R6 has a smaller resistance value than R4. When R6 is connected by the comparison threshold value switching means 17, the combined resistance of R4 and R6 becomes small.

  Here, for example, when another switching power supply device, a capacitor input device, a phase control device, etc. are connected to the same commercial power source 1, if periodic noise occurs in the input waveform of the commercial power source 1, the differential circuit of the surge detection means 9. May detect the noise, and Vs may periodically increase, resulting in a voltage equal to or higher than Vref of the voltage comparison unit 11. In this case, the heating is stopped by the drive stopping means 12 almost in synchronization with the external noise. The stop number measuring means 11 measures the number of times of driving stop for a predetermined time (for example, 1 minute), and if the number of times of driving stop is equal to or larger than the predetermined number of times (for example, 10 times or more), the comparison threshold switching means 17 sets R6. Connecting. As a result, the reference voltage Vref of the voltage comparison unit 13 becomes high and it is difficult to satisfy Vs> Vref, and the voltage comparison unit 10 can suppress sending a stop signal to the drive stop unit 12. Thereby, the case where heating stops and becomes unusable due to periodic external noise or the like different from surge can be reduced. Further, since the switching of R6 is a small signal, it can be performed with an inexpensive transistor or the like.

  Further, when periodic noise is superimposed due to the influence of other equipment, the use of the other equipment may be terminated after that, and the influence of the periodic noise may be eliminated. When heating is continued with the resistor R6 connected at 17, the comparison threshold switching means 17 disconnects the resistor R6 after a predetermined time (approximately 15 minutes in a range that does not affect cooking, for example). As a result, when the external noise that stops the heating is already removed, the operation level of the original differential is obtained, and the device can be protected more safely against a single surge or the like. Moreover, even if heating is once stopped by the user, the initial state in which the resistor R6 is not connected is restored. As a result, the surge detection level is lowered only when periodic external noise is superimposed on the commercial power supply 1 and heating is not possible. In other cases, the surge can be detected to keep the device protected. Is possible.

  Note that the switching of the surge threshold is for switching the reference voltage Vref of the voltage comparison means 10, and there is no change even in the configuration of connection of resistors or connection switching on the R5 side.

  In this embodiment, the inverter circuit is a monolithic voltage resonance inverter. However, in a full-bridge or half-bridge inverter, the same configuration can be used as a protection circuit against a surge superimposed on the commercial power source 1. Similar effects can be obtained.

(Embodiment 4)
FIG. 4 is a configuration diagram of an induction heating cooker according to the fourth embodiment of the present invention. In addition, the same number is given about the structure shown in Embodiment 3, and only a different structure is demonstrated.

  A power supply voltage detection means 14 constituted by resistance voltage division, a band-pass filter 15 that passes about 100 Hz, which is approximately twice the frequency of the commercial power supply 1, and a logic comparator 16 are provided to the output. Vin is detected, and further, the voltage Vin of the commercial power source 1 is detected through the band-pass filter 15. Both of the voltage range in which Vin does not cause a problem even if a normal device is operated in the logical comparator 16 and the switching condition that the number of drive stops for a predetermined time by the stop number measurement cut-off means 11 is periodic are satisfied. In this case, the connection of the resistor R6 is switched by the comparison threshold switching means 17.

  As a result, the surge detection level is switched only in the voltage range where there is no problem even if the normal device is operated, so that the breakdown prevention level of the device is not lowered much.

  Note that the switching of the surge threshold is for switching the reference voltage Vref of the voltage comparison means 10, and there is no change even if it is a resistor connection or a connection switching configuration on the R5 side.

  In this embodiment, the inverter circuit is a monolithic voltage resonance inverter. However, in a full-bridge or half-bridge inverter, the same configuration can be used as a protection circuit against a surge superimposed on the commercial power source 1. Similar effects can be obtained.

As described above, the induction heating cooker according to the present invention switches the voltage detection level between the fluctuation of the power supply voltage caused by lightning, a momentary power failure, etc., and the external noise that occurs almost periodically. it is possible to reduce the situation that can not be heated decommission the will, it can be applied to applications such as induction heating devices other than cooker.

The block diagram of the induction heating cooking appliance in Embodiment 1 of this invention The block diagram of the induction heating cooking appliance in Embodiment 2 of this invention The block diagram of the induction heating cooking appliance in Embodiment 3 of this invention The block diagram of the induction heating cooking appliance in Embodiment 4 of this invention Configuration diagram of a conventional induction heating cooker

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Commercial power supply 4 Inverter circuit 5 Heating coil 6 Resonance capacitor 7 Switching element 8 Drive control means 9 Surge detection means 10 Voltage comparison means 11 Stop frequency measurement means 12 Drive stop means 13 Voltage switching means 14 Power supply voltage detection means 17 Comparison threshold value switching means 17

Claims (6)

An inverter circuit including a heating coil, a resonance capacitor, and a switching element; drive control means for driving and controlling the switching element of the inverter circuit; surge detection means for detecting a surge superimposed on a commercial power supply; and the surge detection means Voltage comparing means for comparing the voltage detected by the surge voltage threshold and a drive for stopping the driving of the switching element when the voltage comparing means determines that the detected voltage by the surge detecting means is higher than the surge voltage threshold and stop means, and number of stops measuring means for measuring the number of stops by the drive stop means, and a voltage switching means for switching the sensed voltage level of the surge detection means, said voltage switching means, the number of stops within a predetermined time There when the predetermined number of times or more, so as to lower the detection voltage level of the surge detection means Induction heating cooker to switch. An inverter circuit including a heating coil, a resonant capacitor, and a switching element, drive control means for driving and controlling the switching element of the inverter circuit, power supply voltage detection means for detecting the voltage of a commercial power supply, and superimposed on the commercial power supply A surge detection means for detecting a surge or the like; a voltage comparison means for comparing a voltage detected by the surge detection means with a surge voltage threshold; and a voltage detected by the surge detection means by the voltage comparison means is higher than the surge voltage threshold. Drive stop means for stopping the driving of the switching element when it is determined, stop number measurement means for measuring the number of stops by the drive stop means, and voltage switching means for switching the detection voltage level of the surge detection means. the voltage switching means is a number of stops within a predetermined time a predetermined number of times or more, and, prior to When the voltage detected by supply voltage detecting means is less than the driving voltage allowed value, the induction heating cooker to switch to lower the detection level of said surge detecting means. When the switching element is driven by the drive control means while the detection level of the surge detection means is switched by the voltage switching means, and the drive stop by the drive stop means is not performed for a predetermined time, the detection switched by the voltage switching means The induction heating cooker according to claim 1 or 2 , wherein the level is returned to the initial level. An inverter circuit including a heating coil, a resonance capacitor, and a switching element; drive control means for driving and controlling the switching element of the inverter circuit; surge detection means for detecting a surge superimposed on a commercial power supply; and the surge detection means Voltage comparing means for comparing the voltage detected by the surge voltage threshold and a drive for stopping the driving of the switching element when the voltage comparing means determines that the detected voltage by the surge detecting means is higher than the surge voltage threshold comprising a stop means, a number of stops measuring means for measuring the number of stops by the drive stopping means, and a comparator threshold switching means before switching the hexa over di voltage threshold, the comparison threshold value switching means, said stop within a predetermined time period An induction heating cooker that switches the surge voltage threshold to a higher voltage when the number of times is equal to or greater than a predetermined number. An inverter circuit including a heating coil, a resonant capacitor, and a switching element, drive control means for driving and controlling the switching element of the inverter circuit, power supply voltage detection means for detecting the voltage of a commercial power supply, and superimposed on the commercial power supply A surge detection means for detecting a surge or the like; a voltage comparison means for comparing a voltage detected by the surge detection means with a surge voltage threshold; and a voltage detected by the surge detection means by the voltage comparison means is higher than the surge voltage threshold. comprising a drive stop means for stopping the driving of the switching element when determining the number of stops measuring means for measuring the number of times stopping by said drive stopping means, and a comparator threshold switching means before switching the hexa over di voltage threshold and the comparison threshold switching means is a number of stops within a predetermined time a predetermined number of times or more, and, the power supply electric When the voltage detected by the detection means is less than the driving voltage allowed value, the induction heating cooker to switch the surge voltage threshold to a higher voltage. In a state where Lisa over di voltage threshold by the comparison threshold value switching means is switched, the switching element is driven by the drive control means, when the driving stop of a predetermined time the drive stopping means is not performed, by the comparison threshold value switching means induction heating cooker according to claim 4 or 5 returns the switched surge voltage threshold value to the initial.

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