JP4978258B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker capable of induction heating a heated body made of a material such as aluminum and iron.

Conventionally, when both aluminum and iron can be inductively heated as the material to be heated, both materials can be inductively heated by changing the resonance current frequency. In order to change the resonance current frequency, a method of switching the capacitance of the resonance capacitor is employed (for example, see Patent Document 1).
JP 2003-151747 A

  However, in the conventional configuration, a plurality of resonance capacitors are connected to the induction heating coil in order to lower the resonance current frequency during iron heating, but one resonance capacitor is used to increase the resonance current frequency during aluminum heating. Switch by switching means so as not to connect. For this reason, when the contact of the switching means is opened for some reason during iron heating, arc discharge may occur. In addition, when aluminum is heated, a voltage of several kV is applied to both ends of the switching means. If there is no margin in the withstand voltage of the contact, if the applied voltage exceeds the withstand voltage of the contact of the switching means for some reason, the switching means Arcing may occur between the contacts. When arc discharge occurs, the contact portion of the switching means becomes very hot, and there is a possibility that a malfunction such as burning of the constituent members of the switching means may occur.

  This invention solves the said conventional subject, and it aims at providing a safe induction heating cooking appliance by stopping a heating at the time of generation | occurrence | production of the arc discharge of a switching means.

In order to solve the conventional problems, an induction heating cooker according to the present invention includes an induction heating coil, a plurality of resonance capacitors connected to the induction heating coil, and switching means for driving the induction heating coil and the resonance capacitor. And a control means for controlling the switching means, and a switching means for switching the plurality of resonance capacitors . When the material of the object to be heated is iron, the capacity of the resonance capacitor is larger than that of aluminum. The switching means switches the capacity of the plurality of resonant capacitors, and further comprises arc discharge detection means for detecting that arc discharge has occurred at the contact of the switching means, and the control means includes the arc discharge detection means in which is to stop the heating by controlling the switching means when detecting arcing.

  As a result, when an arc discharge occurs at the contact of the switching means, the arc discharge detection means detects this, and the control means controls the switching means to stop heating, preventing a burning accident of the switching means, etc. An induction heating cooker can be provided.

  The induction heating cooker according to the present invention stops heating when arc discharge occurs at the contact of the switching means, thereby preventing a burnout accident of the switching means and providing a safe induction heating cooker.

The first invention includes an induction heating coil, a plurality of resonance capacitors connected to the induction heating coil, switching means for driving the induction heating coil and the resonance capacitor , control means for controlling the switching means, Switching means for switching a plurality of resonance capacitors, and when the material of the object to be heated is iron, the switching means causes the resonance capacitors to have a larger capacity than the case of aluminum. with switching capacity, said switch further comprising an arc discharge detecting means for detecting that the arc discharge is generated in the contact means, said control means, said switching means when the arc discharge detecting means detects the arc discharge it is an induction heating cooker to Suspend heating control to. As a result, when an arc discharge occurs at the contact of the switching means, the arc discharge detection means detects this, and the control means controls the switching means to stop heating, preventing a burning accident of the switching means, etc. An induction heating cooker can be provided.

  In particular, in the second invention, in the first invention, the heating operation is stopped due to malfunction of the arc detecting means due to noise or the like by stopping the heating when the arc discharge detecting means detects the arc discharge for a predetermined time or more. Can be prevented.

  In the third aspect of the invention, in particular, in the second aspect of the invention, it is possible to notify the user that an abnormality has occurred in the device by performing error notification when heating is stopped.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the invention, the arc discharge detection means includes an antenna that detects arc discharge, a transistor that is turned on by an increase in voltage across the antenna, And the control means detects the change in the voltage across the capacitor and controls the switching means to easily detect the occurrence of arc discharge at the contact of the switching means. be able to.

  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 and 2 show an induction heating cooker according to an embodiment of the present invention.

  As shown in FIG. 1, the induction heating cooker in the present embodiment is connected to a power source 1, a booster 2, an induction heating coil 3 that heats a heated object such as a pan, and the induction heating coil 3. A plurality of resonance capacitors 4 and 5, a switching means 7 for driving the induction heating coil 3 and the resonance capacitors 4 and 5, a switching means 6 for switching the plurality of resonance capacitors 4 and 5, and a contact point installed in the vicinity of the switching means 6 An arc discharge detecting means 9 for detecting the occurrence of arc discharge at the time, and a control means 8 for stopping the heating by controlling the switching means 7 based on the signal when the arc discharge detecting means 9 detects the arc discharge. I have.

  As shown in FIG. 2, the arc discharge detection means 9 includes an antenna 11 that detects arc discharge in the vicinity of the switching means 6, resistors 12, 13, 14, diodes 15, 16, and an increase in voltage across the antenna 11. And a capacitor 18 whose voltage at both ends changes (decreases) when the transistor 17 is turned on.

  The operation | movement is demonstrated below about the induction heating cooking appliance comprised as mentioned above.

  When heating is started, the resonance current flowing in the induction heating coil 3 and the voltage of the switching means 7 are detected, and the material of the heated object such as a pan is discriminated based on the value. 6 is turned on and the resonant capacitor 5 is connected in parallel to the resonant capacitor 4 to increase the capacitance.

  In this state, when the contact of the switching means 6 is opened due to a malfunction due to the influence of power supply noise or the like, arc discharge due to high voltage and high frequency occurs at both ends of the contact of the switching means 6. When the arc discharge occurs, the arc discharge detection means 9 detects the arc discharge.

  Hereinafter, the operation will be described. When arc discharge occurs, the voltage across the antenna 11 increases, the transistor 17 is turned on via the resistor 12, and the voltage across the capacitor 18 decreases. The control means 8 detects a change in the voltage across the capacitor 18 and turns off the switching means 7 to stop heating.

  On the other hand, if it is determined that aluminum, the control means 8 turns off the switching means 6 and connects only the resonance capacitor 4 to the induction heating coil 3. The voltage across the contact of the switching means 6 is several kV during aluminum heating, but if the withstand voltage is lower than the applied voltage due to insufficient pressure resistance at the contact of the switching means 6, Arc discharge occurs. Also in this case, the arc discharge detecting means 9 detects arc discharge, and the control means 8 detects the arc discharge and stops heating, as in the case where the contact is opened due to a malfunction of the switching means 6 during iron heating. As a result, it is possible to prevent the switching means 6 from being burned out by continuing the arc discharge.

  In order to prevent the heating operation from stopping due to malfunction of the arc discharge detection means 9 due to noise or the like, when the arc discharge detection means 9 detects arc discharge for a predetermined time or longer (for example, 0.1 seconds), The control means 8 may stop heating.

  When the arc discharge detecting means 9 detects an arc discharge, an error notification is displayed on the display portion of the induction heating cooker, an error notification is made with a buzzer or sound, or an error notification is performed by both. Thus, if the user is informed of the abnormality of the device, the usability is improved.

  As described above, the induction heating cooker according to the present invention provides a safe induction heating cooker that prevents the switching means from being burned out by stopping heating when arc discharge occurs at the contact of the switching means. Therefore, it can be applied not only to general households but also to induction heating cookers for business use.

The block diagram which shows the circuit of the induction heating cooking appliance in embodiment of this invention Circuit diagram of arc discharge detection means in the induction heating cooker

Explanation of symbols

3 Induction heating coil 4, 5 Resonance capacitor 6 Switching means 7 Switching means 8 Control means 9 Arc discharge detecting means

Claims (4)

An induction heating coil;
A plurality of resonant capacitors connected to the induction heating coil;
Switching means for driving the induction heating coil and the resonant capacitor;
Control means for controlling the switching means;
Switching means for switching the plurality of resonant capacitors ,
When the material of the object to be heated is iron, the switching means switches the capacity of the plurality of resonance capacitors so that the capacity of the resonance capacitor is larger than that of aluminum, and arc discharge occurs at the contacts of the switching means. Further comprising arc discharge detection means for detecting the occurrence ,
The control means, the induction heating cooker, characterized in that said arc discharge detection means to stop heating by controlling the switching means when detecting arcing. Induction heating cooker of claim 1, wherein the arc discharge detecting means stops heating when detecting arcing predetermined time or more. The induction heating cooker according to claim 1 or 2, wherein an error is notified when heating is stopped. The arc discharge detection device includes an antenna for detecting an arc discharge, a transistor which is turned on by an increase in voltage across the antenna, and a capacitor across voltage decreases by turning the transistor, the control means of the capacitor The induction heating cooker according to any one of claims 1 to 3, wherein the switching means is controlled by detecting a change in voltage at both ends.

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