JP4325446B2 - Induction heating device - Google Patents

Description

  The present invention relates to an induction heating apparatus used in general homes, restaurants, offices, factories and the like.

The conventional induction heating device is operated at a constant driving frequency regardless of the object to be heated. When the voltage duty of the switching means is large, the input power is lowered to reduce the electrical duty of the switching means or the inverter circuit components. The electric duty was reduced (for example, refer to Patent Document 1).
JP-A 63-128581

  However, in the above conventional configuration, since it can only be operated at a constant drive frequency regardless of the object to be heated, when the object to be heated is heated such that the voltage of the switching means becomes large, the input power must be lowered. As a result, the user's feeling of firepower was reduced.

  The present invention solves the above-mentioned problems. The drive frequency of the inverter circuit described above is optimized for the object to be heated, and the reduction in thermal power is suppressed for the user by obtaining the maximum input power. Another object of the present invention is to provide an induction heating device that reduces the electric duty of the switching means or the electric duty of the inverter circuit components.

In order to achieve the above object, an induction heating apparatus according to the present invention includes a plurality of heating coils, and an inverter circuit that is provided in each of the heating coils and that induction-heats an object to be heated by supplying high-frequency current to the heating coils. An input current detecting means for detecting an input current of the inverter circuit; a switching voltage detecting means for detecting a voltage of a switching means for switching a current of a resonance circuit of the inverter circuit; and an operation of the inverter circuit, Control means for driving the inverter at the same frequency in the case of simultaneous heating to suppress the interference sound of the heated object, and the control means detects the material of the heated object by the input current detection means and the switching voltage detection Having a pot type judging means for judging from the information of the means, and when the heating coil operated at the first time is operated, Inductive heating so as to obtain rated input power without switching the drive frequency of the inverter circuit in a region where the switching voltage is less than or equal to a predetermined value with respect to the input current by means of a signal of the means, the switching voltage enters the region a voltage duty that have the potential to allowed to reach greater destroying the switching element of the switching means and performing induction heating by the driving frequency of the intact Ri of higher than the predetermined value one When the heating coil is operated in the second and subsequent operations by performing induction heating by performing a driving frequency switching operation to obtain a rated input power by lowering to the optimum driving frequency of the heating coil operated second. In the second embodiment, the optimum driving frequency of the heating coil that is operated first is the driving frequency of the heating coil that is operated second or later. In which was set to match the frequency.

  As a result, the maximum input power is obtained regardless of the object to be heated, thereby suppressing the reduction of thermal power for the user and reducing the electrical responsibility for the switching means or the inverter circuit components. It is possible to suppress the squealing that occurs due to the difference between the driving frequencies of the plurality of coils.

  As described above, the present invention optimizes the drive frequency of the inverter circuit for the object to be heated and obtains the maximum input power to suppress the reduction of the thermal feeling for the user and to the switching means. However, it is possible to suppress the squealing that occurs due to the difference in the driving frequency of the plurality of coils while reducing the electrical duty or the electrical duty of the inverter circuit components.

The first invention is a plurality of heating coils, an inverter circuit that is provided in each of the heating coils and supplies a high-frequency current to the heating coils to inductively heat an object to be heated, and detects an input current of the inverter circuit An input current detecting means, a switching voltage detecting means for detecting a voltage of a switching means for switching a current of a resonance circuit of the inverter circuit, an operation of the inverter circuit is controlled, and the inverter is operated at the same frequency in the case of a plurality of simultaneous heatings. And a control means for suppressing the interference sound of the heated body, wherein the control means determines the material of the heated body from the information of the input current detection means and the switching voltage detection means. When the heating coil that is operated first is operated, the input current is determined by the signal of the pot type determination means. The switching voltage is inductively heated so as to obtain the input power rating without switching the driving frequency of the inverter circuit in a region equal to or less than a predetermined value, Ri the switching voltage is higher than the predetermined value for the input current optimum of the heating coil to perform the induction heating without changing the driving frequency the operated on the one th voltage duty of the switching means enters increase the area of the switching element that has the potential to allowed to reach breakdown Drive frequency switching operation to obtain a rated input power by lowering to a proper drive frequency, induction heating is performed, and when the heating coil is operated second or later with multiple simultaneous heating, the second or later operation is performed. The driving frequency of the heating coil is adjusted to the optimum driving frequency of the heating coil that is operated first. It is intended. Thereby, the electrical duty of a switching means or the electrical duty of an inverter circuit component can be reduced, and the pot sound which generate | occur | produces by the difference in the drive frequency of several coils can be suppressed.

In the second invention, in particular, the control means of the first invention is such that the operation of the first heating coil is finished and the driving frequency of the heating coil operated second is the optimum driving frequency of the second heating coil. If it is different from the above, the drive frequency switching operation is performed so as to suppress a decrease in the thermal feeling, and the drive frequency of the heating coil operated after the third is also adjusted to the drive frequency of the heating coil operated second. In this way, the drive frequency switching operation is performed by giving priority to the order of the operated heating coils. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

According to the third aspect of the invention, in particular, the control means of the first aspect of the invention is that the heating coil operation operated first is the voltage duty of the switching means increased by the heated object, and the heating coil operated first is optimal. when lowering the driving frequency to the driving frequency is obtained by a configuration to match the driving frequency of the other heating coils to the drive frequency. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

A fourth invention, the control means of the invention, the driving dynamic frequency toggle operation is obtained by gradually performing configuration while operating the inverter circuit. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

A fifth invention is the control means of the invention, the driving dynamic frequency toggle operation, after the inverter circuit is temporarily stopped if in operation, has a configuration which carried out is operated at a driving frequency which is a target Is. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking an induction heating cooker as an example.

  FIG. 1 is a block diagram showing the configuration of the induction heating apparatus according to the first embodiment of the present invention, and FIG. 2 shows the signals and switching of the input current detecting means in the pot type determining means according to the first embodiment of the present invention. It is a graph which shows the relationship of the signal with a voltage detection means. In FIG. 1, 1 is an AC power source, 2 is a rectifier circuit comprising a bridge-connected diode that rectifies the AC power source, 3 is a smoothing circuit comprising a choke coil 3a and a capacitor 3b, 4 is an inverter circuit including switching means 5, 6 Is a heating coil that performs induction heating by applying a high-frequency alternating magnetic field to a heated object 7 such as a pan when supplied with a high-frequency current from the inverter circuit 4, and 8 is an input current detection means that detects the current flowing through the inverter circuit 4. , 9 is a switching voltage detecting means for detecting the voltage applied to the switching means 5 of the inverter circuit 4, the control means 10 is a driving means 11 for driving the switching means 5 for controlling the operation of the inverter circuit 4, and an input current detecting means 8; Pot type determination means 12 for determining the material of the heated object 7 based on the signal of the switching voltage detection means 9. The signal from the pan type determination unit 12 and a driving frequency switching means 13 for switching the driving frequency.

In order to start induction heating, the drive means 11 of the control means 10 outputs a drive signal to the switching means 5, thereby operating the inverter circuit 4 and supplying a high-frequency current to the heating coil 6. By this high-frequency current, the object to be heated 7 such as a pan is induction-heated by the high-frequency magnetic flux generated from the heating coil 6. In order to determine the pot type, the voltage of the input current detecting means 8 and the switching means 5 for detecting the current flowing through the inverter circuit 4 as shown in FIG. Based on the signal from the switching voltage detection means for detecting the signal, it can be used normally in the part other than the shaded area in the figure, that is, in a region where the input current flows to some extent and the switching voltage is also to some extent, in other words, the switching voltage does not increase and is rated. Induction heating is started without being switched by the drive frequency switching means 13 as the heated body 7 to which electric power can be input. For example, when the object 7 to be heated is a magnetic stainless steel pan, it falls within the hatched area in FIG. That is, when the input voltage is small, the switching voltage is high. When induction heating is performed at the drive frequency as it is, the switching voltage becomes high, the voltage duty of the switching means 5 becomes large, and there is a possibility of destruction. In this case, the drive frequency switching means 13 operates to lower the drive frequency of the drive signal sent to the switching means 5 and lower the switching voltage, and performs control to obtain the rated input power. .

  And it has a plurality of heating coils 6 and has a plurality of inverter circuits 4 for controlling each of the heating coils 6, and when a plurality of heating coils 6 are simultaneously heated, the interference sound of the heated object 7 is suppressed by driving at the same frequency. can do.

  When the heating coil 6 operated first is operated, the power input to the heated object 7 is heated at a certain driving frequency to obtain the optimum maximum power, and the second and subsequent heating coils are heated by a plurality of simultaneous heatings. At the time of 6 'operation, the one operated after the second is adjusted to the drive frequency operated first.

  When the operation of the first heating coil 6 is completed and the second heating coil 6 ′ is different from the optimum driving frequency, the driving frequency is switched, and the third and subsequent heating coils 6 ″ are also switched. In this configuration, priorities are set in order of use so as to match the driving frequency of the second heating coil 6 '. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

  The switching of the driving frequency of the inverter circuit 4 is performed gradually while operating. Thereby, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the deterioration of the thermal power feeling is suppressed for the user, and the difference is caused by the difference in driving frequency. Pottering can be suppressed.

The switching of the driving frequency of the inverter circuit 4, after temporarily stopped if in operation, is obtained by the arrangement performed by operating at the drive frequency as a target. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

  In addition, at the time of the first heating coil operation, the power input to the object to be heated is heated at a certain driving frequency to obtain the optimum maximum power, and at the time of the second and subsequent heating coil operations by a plurality of simultaneous heatings, When the voltage duty of the switching means is increased by the heated body and the driving frequency needs to be switched, the driving frequency of the other heating coil is adjusted to the driving frequency. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

  Further, the switching of the drive frequency of the inverter circuit is performed gradually while being operated. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

  In addition, switching of the drive frequency of the inverter circuit is configured to be stopped once during operation and operated at a target drive frequency. As a result, the electric duty of the switching means or the electric duty of the inverter circuit components can be reduced, and the reduction of the thermal feeling is suppressed for the user, and the squealing caused by the difference in driving frequency is suppressed. Can be suppressed.

  The induction heating device of the present invention switches the drive frequency of the inverter circuit according to the material of the object to be heated by the pan type determination means, particularly reduces the voltage duty on the switching means, and reduces the electrical duty of the inverter components, Since the interference sound of the heated object can be reduced, not only induction heating cookers and induction heating rice cookers that have already been put to practical use, but also electric water heaters, electric irons, dishwashers, and water heaters that can be used for induction heating. The present invention can also be applied to uses of heating equipment, and can also be applied to other electrical equipment using an inverter circuit, a microwave oven, a refrigerator, a washing machine, and the like.

The block diagram of the induction heating apparatus in Embodiment 1 of this invention The graph which shows the relationship of the signal of the input current detection means and the signal of the switching voltage detection means in the pan seed | species determination means of the 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectification circuit 3 Smoothing circuit 3a Choke coil 3b Capacitor 4 Inverter circuit 5 Switching means 6 Heating coil 7 Heated body 8 Input current detection means 9 Switching voltage detection means 10 Control means 11 Drive means 12 Pot type determination means 13 Drive Frequency switching means

Claims (5)

A plurality of heating coils, an inverter circuit that is provided in each of the heating coils and that inductively heats the object to be heated by supplying a high-frequency current to the heating coils, and an input current detection means that detects an input current of the inverter circuit; The switching voltage detecting means for detecting the voltage of the switching means for switching the current of the resonance circuit of the inverter circuit, and the operation of the inverter circuit are controlled. Control means for suppressing the interference sound of the heating body, the control means has a pot type determination means for determining the material of the heated body from information of the input current detection means and the switching voltage detection means, the first When the heating coil is operated, the switch for the input current is generated by a signal from the pan type determining means. Grayed voltage induced heating to obtain the input power rating without switching the driving frequency of the inverter circuit in a region equal to or less than a predetermined value, the switching voltage as Ri is higher than the predetermined value for the input current optimum of the heating coil voltage duty is operated in the one th largely entering the area of the switching element that has the potential to allowed to reach disruption of performing said switching means to induction heating by the driving frequency Induction heating by switching to a driving frequency to obtain a rated input power by reducing the driving frequency, and during the operation of the heating coil that is operated second and later by multiple simultaneous heating, the second and subsequent operations An induction heating apparatus in which the driving frequency of the heating coil is adjusted to the optimum driving frequency of the heating coil that is operated first. When the operation of the first heating coil is finished and the driving frequency of the second heating coil is different from the optimum driving frequency of the second heating coil, the control means reduces the thermal power feeling. The order of the heating coils operated by switching the driving frequency so as to suppress and adjusting the driving frequency of the heating coil operated after the third to the driving frequency of the heating coil operated second. The induction heating apparatus according to claim 1, wherein the driving frequency switching operation is performed with priorities assigned to the above. The control means, when the heating coil operation operated first, the voltage duty of the switching means is increased by the object to be heated, and when the driving frequency is lowered to the optimum driving frequency of the heating coil operated first, the control means The induction heating apparatus according to claim 1, wherein the driving frequency of the other heating coil is matched with the driving frequency. The induction heating apparatus according to any one of claims 1 to 3, wherein the control means is configured to gradually perform the drive frequency switching operation while operating the inverter circuit. The control means according to any one of claims 1 to 3, wherein the control means performs the drive frequency switching operation by temporarily stopping the operation if the inverter circuit is in operation and then operating the drive frequency at a target drive frequency. Induction heating device.

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