JP2012248395A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely control input currents including a maximum input current of an apparatus.SOLUTION: Receiving a first signal, Iin adjusting mode control means 12 causes input current control means 10 to change an input current to a first input current value I1 and stores a first detection value T1 output at that time from input current detecting means 9 in first storing means 13. Receiving a second signal during the Iin adjusting mode, the Iin adjusting mode control means 12 causes the input current control means 10 to change the input current to a second input current value I2 smaller than the first input current value I1 and stores a second detection value T2 output from the input current detecting means 9 in second storing means 14. Input current correction means 11 linearly approximates a relationship between the input current value and the detection value based on the first input current value I1, the first detection value T1, the second input current value I2 and the second detection value T2 to obtain a corrected detection value I3 and corrects the detection value to the corrected detection value I3 corresponding to a preset value. The input current control means 10 exerts control so that the corrected detection value I3 is the preset value.

Description

  The present invention relates to correction control of input current of an induction heating cooker.

  Conventionally, when this type of induction heating cooker performs input current correction control, the detection value from the input current detection means when the input supplied from the commercial power supply is the set maximum input current is stored in the storage means, The input current is controlled based on the detected value (see, for example, Patent Document 1).

  FIG. 4 is a block diagram of a conventional induction heating cooker described in Patent Document 1. As shown in FIG. In FIG. 4, the main circuit of the frequency converter 29 includes a rectifier 31 that rectifies the commercial power supply 30, a filter coil 32, a filter capacitor 33, a resonant capacitor 34, and a heating coil 35 connected in parallel to the capacitor. The switching transistor 36 is used.

  On the other hand, the control unit of the frequency converter 29 converts an output voltage of the first input current detection circuit 17 including a current transformer that detects an input current into a digital signal and inputs the digital signal to the microcomputer 19. 18, an A / D converter 21 that converts the output voltage of the collector voltage detection circuit 20 that detects the collector voltage of the switching transistor 36 into a digital signal and inputs it to the microcomputer 19, and a set value storage comprising a nonvolatile digital storage element A circuit 22 and a correction start switch 23 are provided.

  Further, an input terminal 26 that is installed outside the device and is detected by the second input current detection circuit 24 that detects the input current and is digitized by the A / D converter 25 is disposed in the control unit. Has been. A signal input from the input terminal 26 is input to the microcomputer 19. The output voltage of the second input current detection circuit 24 and the output voltage of the A / D converter 25 are softened with high precision so that the relationship between the predetermined input current and the output voltage can be accurately obtained.

JP-A-2-270292

  However, in the conventional configuration, when the input current correction control is performed, since the error of the input current value other than the maximum input current due to the performance variation of each product is not taken into consideration, the performance of the low input current of the device varies. When this occurs, there is a problem that input current values other than the maximum input current (particularly at low currents) cannot be controlled with high accuracy.

  This invention solves the said conventional subject, and it aims at providing the induction heating cooking appliance which can control not only the maximum input current but input currents other than the maximum input current accurately.

In order to solve the conventional problems, an induction heating cooker according to the present invention includes a main body constituting an outer shell, a top plate provided on an upper surface of the main body, and an object to be heated placed on the top plate. A heating coil for induction heating with a high frequency current, an inverter circuit for supplying a high frequency current to the heating coil, an input current detection means for detecting an input current input to the inverter circuit, and a detection output by the input current detection means Input current control means for controlling the operation of the inverter circuit so that the value becomes a set value selected from a plurality of set values, and the detected value output from the input current detection means is corrected to correct the input current An input current correction unit that outputs a detection value after correction to the control unit; and an Iin adjustment mode control unit that has an input terminal for inputting a signal and controls the Iin adjustment mode. The mode control means shifts the control of the input current control means to the Iin adjustment mode when a start signal is inputted from the input terminal, and the input current control means when the first signal is inputted from the input terminal during the Iin adjustment mode. Based on the instruction of the first signal, the input current is changed to the first input current value, and the first detection value output by the input current detection means at that time is stored in the first storage means, and the Iin adjustment mode is in progress. When a second signal is input to the input terminal, the input current control means changes the input current to a second input current value smaller than the first input current value based on an instruction of the second signal, and then detects the input current. The second detection value output by the means is stored in the second storage means, and the input current correction means is configured to output the first input current value, the second input current value, and the first detection value and From the second detection value, the relationship between the input current value and the detection value is linearly approximated to obtain the corrected detection value, and the detection value is corrected to the detection value after correction corresponding to the set value, The input current control means is controlled so that the corrected detection value becomes the set value.

  Accordingly, a detection value when an input current other than the first input current value and the second input current value is input can be predicted with high accuracy, and any level of input current value can be input with high accuracy.

  The induction heating cooker of the present invention can accurately input any level of input current value.

The block diagram which shows the structure of the induction heating cooking appliance in Embodiment 1 of this invention. The correction figure which showed the relationship between the input current value of correction | amendment performed with the input current correction means of the induction heating cooking appliance in Embodiment 1 of this invention, and a detected value The actual relationship line L0 and the first approximate line L1 of the input current value and the detected value of the induction heating cooker in Embodiment 1 of the present invention, and the line L2 obtained by linearly approximating the relationship between the input current value and the detected value in the prior art Relationship diagram showing the relationship Block diagram of a conventional induction heating cooker

According to a first aspect of the present invention, there is provided a main body constituting an outer shell, a top plate provided on an upper surface of the main body, a heating coil for induction heating an object to be heated placed on the top plate with a high frequency current, and the heating coil An inverter circuit that supplies a high-frequency current to the input circuit, an input current detection unit that detects an input current input to the inverter circuit, and a setting in which a detection value output from the input current detection unit is selected from a plurality of setting values Input current control means for controlling the operation of the inverter circuit so as to become a value, and input current correction for correcting the detection value output from the input current detection means and outputting a corrected detection value to the input current control means And an Iin adjustment mode control means for controlling the Iin adjustment mode having an input terminal for inputting a signal, and the Iin adjustment mode control means receives a start signal from the input terminal. The input current control means shifts to the Iin adjustment mode, and when the first signal is input from the input terminal during the Iin adjustment mode, the input current control means is supplied with the input current based on the instruction of the first signal. Is changed to the first input current value, the first detection value output by the input current detection means at that time is stored in the first storage means, and the second signal is input from the input terminal during the Iin adjustment mode. Based on the instruction of the second signal, the input current control means changes the input current to a second input current value smaller than the first input current value, and a second detection value output by the input current detection means at that time The input current correction means stores the input current value based on the first input current value, the second input current value, the first detection value, and the second detection value. The corrected detection value is corrected to the corrected detection value corresponding to the set value, and the input current control means has the corrected detection value set to the set value. It controls to become.

  As a result, it is possible to accurately predict a detection value when a predetermined input current other than the first input current value and the second input current value is input, and by controlling based on the detection value, any level of the input current value can be accurately detected. It can be controlled well.

  In the second invention, in particular, when the Iin adjustment mode control means of the first invention inputs the second signal from the input terminal during the Iin adjustment mode, the input current is supplied to the input current control means based on the instruction of the second signal. Instead of storing the second detection value output by the input current detection means at that time in the second storage means in the second storage means, the operation of the inverter circuit is stopped. The second detection value output by the input current detection means is stored in the second storage means, and the input current correction means is the first input current value, the second input current value and the first detection value, Instead of linearly approximating the relationship between the input current value and the detected value from the second detected value to obtain a corrected detected value and correcting the detected value to the corrected detected value corresponding to a set value, The input current correction means includes the first current value and The first detection value, 0, and the second detection value are used to obtain a corrected detection value by linearly approximating the relationship between the input current value and the detection value, and the detection value corresponds to the set value. By correcting to the detection value after correction, the second signal can be deleted and work efficiency can be improved.

  In the third invention, in particular, the difference between the first input current value and the second input current value can be increased by setting the first input current value of the first or second invention to the maximum input current of the device. In addition, the input current can be controlled more comprehensively and accurately than when the difference is narrow.

  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 block diagram showing the configuration of the induction heating cooking appliance according to the first embodiment of the present invention.

  In FIG. 1, a commercial power source 1, a rectifier 2, a printed wiring board 3, a main body 4 constituting an outer shell, a top plate 5 provided on an upper surface of the main body 4, a heated object 6 placed on the top plate 5, A heating coil 7 that induction-heats the heated object 6 with a high-frequency current, an inverter circuit 8 that supplies the heating coil 7 with a high-frequency current, an input current detection means 9 that detects an input current input to the inverter circuit 8, and an input current detection means 9 The input current control means 10 for controlling the operation of the inverter circuit 8 and the detection value output from the input current detection means 9 are corrected so that the detection value output from the input circuit becomes a set value selected from a plurality of set values. Input current correction means 11 for outputting a detection value after correction to the input current control means 10, Iin adjustment mode control means 12 having an input terminal 12a for inputting a signal and controlling the Iin adjustment mode, input current detection Are constituted by the second storage means 14 for storing the second detection value the first storage unit 13, an input current detecting means 9 for storing the first detection value stage 9 outputs to output.

  About the induction heating cooking appliance comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

First, when the Iin adjustment mode control means 12 inputs a start signal from the input terminal 12a, the control of the input current control means 10 shifts to the Iin adjustment mode, and when the first signal is input from the input terminal 12a during the Iin adjustment mode. Based on the instruction of the first signal, the input current control means 10 changes the input current to the first input current value, and the first detection value output by the input current detection means 9 at that time is stored in the first storage means 13. When the second signal is inputted from the input terminal 12a during the Iin adjustment mode, the input current is changed to the second input current value smaller than the first input current value to the input current control means 10 based on the instruction of the second signal. Then, the second detection value output by the input current detection means 9 at that time is stored in the second storage means 14.

The start signal may be the same as the first signal or the second signal, or may be a different signal. The Iin adjustment mode refers to a mode in which the following operations i and ii are performed when a signal is input to the input terminal 12a, and i and ii are out of order.
i: The input current is changed to the first input current based on the signal input to the input terminal 12a, and the first detection value output by the input current detection means 9 at that time is stored in the first storage means 13. Let
ii: The input current is changed to the second input current based on a signal input to the input terminal 12a, and the second detection value output by the input current detection means 9 at that time is stored in the second storage means 14. Let

  FIG. 2 is a correction diagram showing the relationship between the input current value of correction performed by the input current correction means 11 of the induction heating cooker and the detected value in the first embodiment of the present invention. The input current correction unit 11 will be described.

  In FIG. 2, L0 is an actual characteristic showing the relationship between the input current value of a device whose performance varies and the detected value output by the input current detecting means 9 when the input current is the input current value. L1 is a first approximate line obtained by linearly approximating the relationship between the input current value and the detected value from the first input current value I1, the first detected value T1, the second input current value I2, and the second detected value T2.

The input current correction means 11 obtains a corrected detection value I3 from the first approximate straight line L1, and corrects the detection value T3 to a corrected detection value I3 corresponding to the set value.
The input current control means 10 performs control so that the corrected detection value I3 becomes the set value.

  As described above, in the present embodiment, the input current correction unit 11 detects the input current value and the detection value from the first input current value I1, the first detection value T1, the second input current value I2, and the second detection value T2. By linearly approximating the relationship with the value, the difference between the actual relationship line L0 and the first approximate line L1 can be reduced, and the detection value T3 is corrected to the corrected detection value I3 from the first approximate line L1, By controlling the corrected detection value I3 to be the set value, it is possible to accurately control the input current value at any level.

  This will be described in comparison with the prior art using FIG. FIG. 3 shows the relationship between the input current value and the detected value of the induction heating cooker according to the first embodiment of the present invention, the actual relationship line L0 and the first approximate line L1 between the input current value and the detected value. It is a relationship figure showing the relation of line L2 which carried out straight line approximation.

  In FIG. 3, I4 is a maximum input current value of the device, T4 is a detection value output by the input current detection means 9 when the input current is the maximum input current value of the device, and T5 is a detection value output by the device to the input current correction means 11. It is a preset fixed value that cannot be changed and is estimated as a detection value when the input current of the device is 0 from the beginning.

  L2 is the relationship between the input current value and the detected value from the maximum input current value I4 of the device and the detected value T4 of the maximum input current value of the device, the detected value when the input current is 0, and the preset fixed value T5. Is a conventional approximate line obtained by linearly approximating.

  Δ1 is an input current error representing a difference in input current value at the same detected value between the actual relation line L0 and the conventional approximate line L2.

  As shown in FIG. 3, since the first approximate straight line L1 has a smaller error from the actual relationship line L0 than the conventional approximate straight line L2, more accurate input current control can be performed.

  In this embodiment, when the Iin adjustment mode control means 12 inputs the second signal from the input terminal 12a during the Iin adjustment mode, the input current is supplied to the input current control means 10 based on the instruction of the second signal. The second input current value I2 smaller than the value I1 is changed.

  Instead of storing the second detection value T2 output by the input current detection means 9 at that time in the second storage means 14, the second detection value T2 output by the input current detection means 9 while the operation of the inverter circuit 8 is stopped. The detection value T2a is stored in the second storage means 14, and the input current correction means 11 receives the input current from the first input current value I1, the first detection value T1, the second input current value I2, and the second detection value T2. Instead of linearly approximating the relationship between the detected value and the detected value to obtain a corrected detected value I3 and correcting the detected value to the corrected detected value I3 corresponding to the set value, the input current correcting means 11 is the first input The relationship between the input current value and the detected value is linearly approximated from the current value I1, the first detected value T1 and 0, and the second detected value T2a output from the input current detecting means 9 while the operation of the inverter circuit 8 is stopped. The corrected detection value I3 is obtained and the detection value is Serial By was corrected to the corrected detection value I3 corresponding to the setting value, it is possible to improve the efficiency of work can remove the second signal.

  Further, by setting the first input current value I1 of the present embodiment to the maximum input current value I4 of the device, the difference between the first input current value I1 and the second input current value I2 can be widened. Compared to when the difference between the input current value I1 and the second input current value I2 is narrow, it is possible to control the input current with higher accuracy overall.

  The input current detection means 9 is composed of a current transformer and a microcomputer. The input current control means 10, the input current correction means 11, the first storage means 13, the second storage means 14, and the Iin adjustment mode control means 12 are Even if it is constituted by a microcomputer, the same effect can be obtained.

  As described above, the induction heating cooker according to the present invention can accurately input the instructed input power value, so that it can be used for equipment using other inverter circuits that require accurate control of the input current value. It can also be applied.

DESCRIPTION OF SYMBOLS 1,30 Commercial power supply 2,31 Rectifier 3 Printed wiring board 4 Main body 5 Top plate 6 Heated object 7, 35 Heating coil 8 Inverter circuit 9 Input current detection means 10 Input current control means 11 Input current correction means 12a, 26 Input terminal 12 Iin adjustment mode control means 13 First storage means 14 Second storage means I1 First input current value T1 First detection value I2 Second input current value T2 Second detection value T2a The operation of the inverter circuit 8 is stopped Second detection value output by the input current detection means 9 T3 detection value I3 detection value after correction I4 maximum input current value of device T4 detection value of maximum input current value of device T5 preset fixed value L2 conventional A line that approximates the relationship between the input current value and the detected value with technology using a straight line (conventional approximate line)
ΔI Input current error

Claims (3)

A main body constituting the outer shell, a top plate provided on the upper surface of the main body, a heating coil for induction heating an object to be heated placed on the top plate by a high frequency current, and a high frequency current to the heating coil An inverter circuit; input current detection means for detecting an input current input to the inverter circuit; and a detection value output from the input current detection means so as to be a set value selected from a plurality of set values. Input current control means for controlling the operation of the inverter circuit; input current correction means for correcting the detection value output from the input current detection means and outputting the corrected detection value to the input current control means; and a signal input And an Iin adjustment mode control means for controlling the Iin adjustment mode, and the Iin adjustment mode control means receives the start signal from the input terminal. When the control of the force / current control means shifts to the Iin adjustment mode and the first signal is input from the input terminal during the Iin adjustment mode, the input current is first input to the input current control means based on the instruction of the first signal. When the input current value is changed and the first detection value output by the input current detection means is stored in the first storage means, and the second signal is input from the input terminal during the Iin adjustment mode, the input current Based on the instruction of the second signal, the control means changes the input current to a second input current value smaller than the first input current value, and the second detection value output by the input current detection means at that time is stored in the second memory. And the input current correction means determines the relationship between the input current value and the detected value from the first input current value, the first detected value, the second input current value, and the second detected value. Straight line Similarly, the corrected detection value is obtained and the detected value is corrected to the corrected detection value corresponding to the set value, and the input current control means controls the corrected detection value to be the set value. Induction heating cooker. When the second signal is input from the input terminal during the Iin adjustment mode, the Iin adjustment mode control means changes the input current to a second input current value smaller than the first input current value based on the instruction of the second signal to the input current control means. Then, instead of storing the second detection value output by the input current detection means at that time in the second storage means, the second detection value output by the input current detection means while the operation of the inverter circuit is stopped. Is stored in the second storage means, and the input current correction means determines the input current value and the detected value from the first input current value, the second input current value, the first detected value, and the second detected value. Instead of obtaining a corrected detection value by linear approximation and correcting the detection value to the corrected detection value corresponding to a set value, the input current correction means includes the first current value and the first current value. Detection value of 0 and the second 2. The correction value according to claim 1, wherein the corrected detected value is obtained by linearly approximating a relationship between an input current value and the detected value from an output value, and the detected value is corrected to the corrected detected value corresponding to the set value. Induction heating cooker. The induction heating cooker according to claim 1 or 2, wherein the first input current value is a maximum input current value of the device.