JPH0963760A - Induction heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically adjust the input power to an exciting coil. SOLUTION: An adjustment control means 18 is selected so that the input power of are exciting coil 7 and the adjustment power of an adjustment power memory 21 coincide with each other. An input current correction value computing means 22 compares each output signal from an input voltage detecting means 14 and an input current detecting means 16 with the described adjustment power, and computes a correction value of the input current. Input power to the exciting coil 7 is thereby automatically adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electromagnetic induction heating (hereinafter,
Called IH. ) Type induction heating device having a built-in microcomputer such as a warming pot.

[0002]

Generally, an induction heating apparatus of this type is composed of an input voltage detecting means for detecting an input voltage from a commercial power source and an input current detecting means for detecting an input current from the commercial power source. Monitor each output signal so that the desired input power is supplied to the oscillation coil that is the load.
Control is performed by an input power adjusting means incorporated in a microcomputer.

However, the relationship between the input voltage and the input current of the commercial power source and the input power to the load causes an error for each product due to variations in elements forming the circuit. In particular, the output signal from the input current detection means tends to vary greatly due to the influence of the oscillating coil and the induced object, and the semi-fixed resistor is used for each device to correct the output signal before the product is shipped to correct the input power. It had to be adjusted. Therefore, conventionally, an adjusting tool such as a screwdriver for rotating the semi-fixed resistor is required, an adjusting hole for inserting a driver must be provided in the device, and the element is directly contacted during adjustment, which may cause an electrical short circuit. However, there are various problems such as adjustment being time-consuming due to physical manual work, and productivity is poor.

In view of the above problems, it is an object of the present invention to provide an induction heating device capable of automatically adjusting the input power to a load without using an adjustment tool.

[0005]

An induction heating device of the present invention is an output signal of an input voltage detecting means for detecting an input voltage from a commercial power source and an input current detecting means for detecting an input current from the commercial power source. Thus, in the induction heating device including the microcomputer for controlling the input power to the load by the input power adjusting means, the adjusted power storage means for storing a predetermined adjusted power and the load by stopping the control by the input power adjusting means. Adjustment control means for varying the input power of, and the adjusted power stored in the adjusted power storage means when the input power of the load matches the adjusted power stored in the adjusted power storage means by the adjustment control means. And the respective output signals of the input voltage detection means and the input current detection means are compared to calculate a correction value of the input current from the input current detection means. An input current correction value calculating means for,
An input current correction value storage means for storing the correction value calculated by the input current correction value calculation means, and an output signal from the input current detection means by using the correction value stored in the input current correction value storage means The microcomputer is further provided with an input current correction means for correction.

According to the above configuration, when the adjustment control means incorporated in the microcomputer matches the input power of the load with the adjustment power stored in the adjustment power storage means, the input current also incorporated in the microcomputer. The correction value calculation means compares each output signal of the input voltage detection means and the input current detection means at this point with the adjusted power stored in the adjusted power storage means to correct the input current from the input current detection means. I try to calculate the value. Therefore, even without using a semi-fixed resistor as in the past, the output signal from the input current detection means, which has a relatively large variation among products, can be automatically used by utilizing the software function stored in the microcomputer. Can be corrected to. If the correction value calculated by the input current correction value calculation means is stored in the input current correction value storage means, the feedback control by the input power adjustment means is performed based on the corrected output signal from the input current detection means. You can

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to an IH type warming pot will be described below with reference to the attached FIGS. FIG.
Shows the overall configuration of the system during adjustment and inspection before product shipment. In the figure, 1 is a commercial power supply, 2
Is an IH type warming pot with a built-in microcomputer 3, and the input power from the commercial power source 1 is supplied from the IH oscillating power source circuit 4 having a rectifying and smoothing circuit in the IH type warming pot 2 to the IH oscillation circuit 5 And via the IH drive circuit 6,
It is adapted to be supplied to the oscillation coil 7 which is a load. The IH oscillation circuit 5 supplies a predetermined high frequency current to the oscillation coil 7 by resonance with the oscillation coil 7.
Further, the IH drive circuit 6 controls the switching on and off to the oscillation coil 7 while varying the high frequency current from the IH oscillation circuit 5 based on the drive signal from the drive signal generating means 8. Then, when a high-frequency current is supplied to the oscillation coil 7, an eddy current is generated in a heating layer of a pan (not shown) facing the oscillation coil 7, and the eddy current is converted into Joule heat, so that the heating layer is formed. It is configured to generate heat and heat the pot.

On the other hand, the microcomputer 3 carries out various controls for the oscillation coil 7 etc. according to the control sequences of a plurality of programs held by itself.
The control means 11 is provided. The IH control means 11 is a heating control means for sequentially instructing the required input power of the oscillation coil 7.
12, input voltage detection means 14 for detecting the input voltage from the commercial power supply 1 input from the IH oscillation power supply circuit 4 via the input voltage signal generation means 13, and also input from the IH oscillation power supply circuit 4. Input voltage detecting means 16 for detecting an input current from the commercial power supply 1 inputted via the current signal generating means 15, and electric power obtained by each output signal from the input voltage detecting means 14 and the input current detecting means 16. So that the value matches the input power indicated by the heating control means 12,
Input power adjusting means for adjusting and controlling the input power of the oscillation coil 7 via the drive signal generating means 8 and the IH drive circuit 6.
It has 17 and. Further, 18 is an adjustment control means that is activated when calculating the correction value of the input current, and when this adjustment control means 18 is selected, the input power adjustment means 17 causes the input voltage detection means 14 and the input current described above. Stop the feedback control of the input power by the output signal from the detection means 16,
The instruction of the adjustment control means 18 is preferentially followed. Specifically, when the adjustment control means 18 is activated, the mode is switched to a program mode for calculating the correction value of the input current, and the input power of the oscillation coil 7 is changed to the IH drive circuit 6 according to the control signal from the adjustment control means 18. It becomes variable via.

In addition to the above, the IH control means 11 outputs each output signal from the input voltage detection means 14 and the input current detection means 16,
An input current correction value calculation means 22 for calculating a correction value of the input current from the input current detection means 16 by comparing with the adjusted power stored in advance in the adjusted power storage means 21, and this input current correction value calculation means 22 By using the input current correction value storage means 23 for storing the correction value calculated in step 1, and the correction value stored in the input current correction value storage means 23 And an input current correction means 24 for correcting the output signal. Then, the input current correction value calculation means 22 is a control sent from the adjustment control means 18 when the input power of the oscillation coil 7 matches the adjusted power stored in the adjusted power storage means 21 during the operation of the adjustment control means 18. It is designed to operate by signals. Further, 25 is a communication means for starting and controlling the adjustment control means 18 from the outside. 26 is an operation key as an operation means for setting a normal rice cooking course and clock time, and executing and stopping each process such as rice cooking and heat retention. For example, while simultaneously pressing a plurality of operation keys 26, the commercial power source 1 is turned on. The IH control means 11 is configured so that the adjustment control means 18 can be activated when a special key operation is performed by turning it on. In this case, the input power to the oscillating coil 7 can be changed, and the subsequent operation instruction to the input current correction value calculating means 22 can be performed by operating the operation key 26.

Reference numeral 31 is an adjusting device for automatically adjusting and inspecting each IH type warming pot 2. The adjusting device 31 includes an input power detecting means 32 such as a wattmeter for detecting the input power of the oscillation coil 7 and the IH control means 11
The adjusted power storage means 33 for storing the adjusted power having the same value as the adjusted power storage means 21 in the inside, and the power value obtained by the input power detection means 32 and the adjusted power stored in the adjusted power storage means 33 are compared. Communication means for the electric power comparison means 34 and the IH type warmer 2
Adjustment control means 35 connected to 25. Among them, the adjustment control means 35 of the adjusting device 31 is for starting and controlling the adjustment control means 18 of the IH type warmer 2 from the outside, but the power value from the input power detection means 32 and the adjusted power storage means. When the power comparison means 34 notifies that the adjusted powers stored in the 33 match, the request signal for operating the input current correction value calculation means 22 is output to the adjustment control means 18. In addition,
The adjusting device 31 according to the present embodiment is capable of adjusting and inspecting a plurality of types of IH type heat insulation pots 2 having different specifications.
Corresponding to this, the adjusted power storage means 33 stores a plurality of adjusted power values.

FIG. 2 shows a simplified configuration of the system shown in FIG. 1. In FIG. 2, 41 is the oscillation coil 7.
It is the IH means of the IH type warmer 2 including the
An outlet plug 42 for supplying power to the means 41 is connected to the input detection means 32 of the adjusting device 31 connected to the commercial power supply 1. In addition to the above-mentioned IH control means 11, the microcomputer 3 is provided with a time setting means 43 for setting the time of a built-in clock. On the other hand, the adjusting device 31 includes a CPU 44 and a reference clock 45 for measuring a reference time, and a communication cable 46 enabling bidirectional communication between the CPU 44 and the microcomputer 3 is connected between them.
Although it is possible to set the time for the IH type warmer 2 with the operation keys 26, the CPU 44 of the adjusting device 31 is set.
It is also possible to send the time data from the to the clock setting means 43. Further, 47 is a start switch for starting the operation of the adjusting device 31, and when the start switch 47 is pushed, data is transmitted / received between the CPU 44 and the microcomputer 3 according to a program incorporated in the adjusting device 31. Meanwhile, a series of adjustment and inspection procedures for the IH type warmer 2 are automatically performed.

Next, the operation of the above structure will be described. First, the procedure for controlling the input power of the oscillation coil 7 by the input power adjusting means 17 before adjustment will be described. The input power adjusting means 17 includes the input voltage detecting means 14 and the input current detecting means.
Using each of the 16 output signals as they are, the power value calculated by the product of voltage and current is calculated. At this time, when the power value obtained by the calculation is higher than the input power instructed by the heating control means 12, a signal that considerably reduces the input power to the oscillation coil 7 is output to the IH drive circuit 6. On the contrary, when the calculated electric power value is lower than the input electric power instructed by the heating control means 12, the signal for lowering the input electric power to the oscillation coil 7 by a considerable amount is output to the IH drive circuit 6. Thus
The input power adjusting means 17 performs feedback control while monitoring the output signals of the input voltage detecting means 14 and the input current detecting means 16 so that the input power of the oscillation coil 7 matches the instruction value from the heating control means 12. To do.

Next, the automatic adjustment and inspection procedure using the adjusting device 31 will be described in detail with reference to Table 1 showing the contents of communication between the adjusting device 31 and the IH type warming pot 2.

[0014]

[Table 1]

The CPU 44 of the adjusting device 31 sequentially executes each item of numbers 1 to 6 shown in Table 1. In the first item of "reset", a reset signal is sent from the adjusting device 31 to the IH type warming pot 2. As a result, the IH control means 11
Controls the adjustment control means 18 instead of the input power adjustment means 17 with priority. In the next item of "communication start", a start signal indicating the start of communication is sent from the adjusting device 31 to the IH type warmer kettle 2. Adjustment control means receiving this start signal
18 sends an echo back signal confirming the connection of the communication cable 46 to the adjusting device 31. If the echo back signal is not received within a predetermined time, that is, 5 seconds after sending the reset signal, the adjusting device 31 notifies that there is an abnormality by a notifying means (not shown) such as a buzzer. Also, when the echo back signal is not a specific data code, the adjusting device 31 gives an abnormality notification.

When the communication is confirmed by both the adjusting device 31 and the IH type warmer 2, the item "clock adjustment" is performed. This "clock adjustment" is to match the time of the reference clock 45 held by the adjusting device 31 with the time of the time setting means 43. Specifically, the adjusting device 31 outputs one minute digit, 1
4-bit time data indicating 0 minute digit, 1 hour digit, and 10 hour digit are sequentially sent out, and after receiving each echo back signal from the IH type warmer 2, the notification signal indicating the completion of transmission of the time data is adjusted. Send it out from the device 31 to the IH type warmer 2
The time data of the time setting means 43 is rewritten. Also in this case, when the echo back signal cannot be received within a predetermined time or the echo back signal of a different code is received, the adjusting device 31 gives an abnormality notification.

After that, the adjusting device 31 performs "IH watt adjustment".
Item. In this "IH watt adjustment", a notification signal for starting the adjustment of the input power of the oscillation coil 7 is sent from the adjustment control means 18 of the IH type warmer 2 to the adjustment control means 35 of the adjustment device 31. The adjusting device 31 detects the input power of the oscillation coil 7 by the input power detecting means 32, and
The electric power value obtained by the input electric power detection means 32 and the adjusted electric power stored in the adjusted electric power storage means 33 are compared by the electric power comparison means 34, and information of plus or minus how many watts with respect to the adjusted electric power is adjusted and controlled. Send to 35. Then, based on the comparison information from the power comparison means 34, a 4-bit request signal for increasing or decreasing the input power of the oscillation coil 7 is sent from the adjustment control means 35 via the communication means 25 to the IH warming pot 2. It is sent to the adjustment control means 18. Adjustment control means 18
Immediately sends the echo back signal to the adjustment control means 35, and in response to the request signal from the adjustment control means 35,
A control signal for increasing or decreasing the input power of the oscillation coil 7 is output to the IH drive circuit 6. This adjustment control means 35
The request signal from is sent a plurality of times (n times) until the power value obtained by the input power detection means 32 matches the adjusted power stored in the adjusted power storage means 33.

In this way, the adjustment control means 18 adjusts the input power to the oscillating coil 7 so that the power value obtained by the input power detection means 32 matches the adjusted power stored in the adjusted power storage means 33. From the adjustment control means 35 of the adjustment device 31 to the adjustment control means 18 of the IH warming pot 2, the input current detection means 16
A request signal is sent out to calculate the correction value of the input current from. Upon receiving this request signal, the adjustment control means 18 instructs the input current correction value calculation means 22 to calculate the correction value. The input current correction value calculation means 22 reads each output signal of the input voltage detection means 14 and the input current detection means 16 at the time when the correction value calculation request is made, and the adjusted power storage means 21.
The correction value of the input current is calculated based on the following formula 1 by comparison with the adjusted power stored in

[0019]

[Equation 1]

Then, the correction value obtained by the input current correction value calculation means 22 is stored in the input current correction value storage means 23, and the item "IH watt adjustment" ends.

The next item of "automatic switch inspection" is "I
Subsequent to the "H watt adjustment", the operation is performed until the pot temperature of the IH type warmer 2 rises to a predetermined temperature while keeping the input power of the oscillation coil 7 constant. Specifically, first, when the notification signal for starting the automatic switch operation is sent from the adjustment control means 18, the adjustment control means 35 of the adjustment device 31 starts the required time measurement, and then the automatic control operation is started from the adjustment control means 18. When the notification signal indicating the completion is sent, the adjustment control means 35 ends the measurement of the required time. If the "automatic switch inspection" and the "IH watt adjustment" described above are not completed within a predetermined time, for example, 15 seconds, the adjusting device 31 issues an abnormality notification.

The last item of "heat retention heater inspection" is a heat retention heater (not shown) different from the oscillation coil 7.
It is to inspect whether or not it is operating normally. In this item, first, the adjustment control means 18 sends a notification signal for energizing the heat retention heater to the adjustment control means 35. Adjustment device
In response to this notification signal, the input power detection means 32 detects the input power of the warming heater. Then, if the power value obtained by the input power detection means 32 is within a predetermined management value, the adjustment control means 35 sends a notification signal indicating the completion of the inspection of the heat retention heater to the adjustment control means 18, and a series of procedures. To finish. On the contrary, if the power value obtained by the input power detecting means 32 is out of the predetermined control value, the adjusting device 31 gives an abnormality notification.

The required time for each item from "reset" to "heat retention heater inspection" is as shown in the right column of Table 1, and the total required time is about 15 seconds. If the required time exceeds 40 seconds, the adjusting device 31 gives an abnormality notification. When the adjusting device 31 determines that there is an abnormality, the adjusting control means 35 sends out a reset signal.

After the adjustment by the adjustment control means 18, the output signal from the input current detection means 16 is corrected based on the correction value stored in the input current correction value storage means. Therefore, the input power adjusting means 17 determines that the power value obtained by the corrected output signal from the input current detecting means 16 and the output signal from the input voltage detecting means 14 is the heating control means 12
The input power to the oscillating coil 7 is feedback-controlled so as to match the input power instructed by.

As described above, in the present embodiment, when the adjustment control means 18 incorporated in the microcomputer 3 matches the input power of the oscillation coil 7 with the adjusted power stored in the adjusted power storage means 21, Similarly, the input current correction value calculation means 22 incorporated in the microcomputer 3 calculates the output signals of the input voltage detection means 14 and the input current detection means 16 at this time point and the adjusted power stored in the adjusted power storage means 21. By comparison, the correction value of the input current from the input current detecting means 16 is calculated. Therefore, without using a semi-fixed resistor as in the prior art, the output signal from the input current detection means 16 having a relatively large variation between products can be utilized by utilizing the software function stored in the microcomputer 3. If it can be automatically corrected and the correction value calculated by the input current correction value calculation means 22 is stored in the input current correction value storage means 23, based on the corrected output signal from the input current detection means 16, Feedback control by the input power adjusting means 17 can be performed.

That is, the microcomputer 3 having the input power adjusting means 17 is provided with the adjusting control means 18, the adjusted power storage means 21, the input current correction value calculation means 22, the input current correction value storage means 23 and the input current correction means 24. By adding more, without using an adjustment tool such as a driver,
The adjustment work of the input power to the oscillation coil 7 can be automatically performed, and the adverse effects of the conventional adjustment work by the semi-fixed resistor can be eliminated.

In this embodiment, a dedicated adjusting device 31 is provided as means for controlling the adjustment control means 18 from the outside, but the microcomputer 3 is constructed so that the adjustment control means 18 can also be controlled by the operation keys 26. Preferably. This is an operation key if there is a wattmeter that can measure the input power to the oscillation coil 7 without the adjustment device 31.
This is because the correction value can be easily calculated and stored by the operation of 26, which is particularly useful in terms of service such as when repairing the IH type warmer 2.

Further, in this embodiment, since the microcomputer 3 is provided with the time setting means 43 capable of rewriting the time based on the time data sent from the adjustment control means 35 of the adjusting device 31, the operation keys are individually operated. Even if you do not operate the 26, you can automatically adjust the clock of the IH type warming kettle 2 based on the time data sent from the adjusting device 31. It is possible to prevent troubles such as an increase in man-hours due to troublesome work. Moreover, since the microcomputer 3 also incorporates an automatic switch inspection means for automatically inspecting the switch and a heat retention heater inspection means for inspecting the heat retention heater, there is a manufacturing advantage that each of these inspections can be performed at the same time. It should be noted that various kinds of adjustment and inspection means added to these adjustment control means 18 may be incorporated in the microcomputer 3 as appropriate according to the specifications of the IH type heat retention pot 2.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the gist of the present invention. For example, the present invention is not limited to the warming pot in the embodiment, and it goes without saying that the present invention can be applied to other IH type rice cookers and cookers.

[0030]

According to the induction heating apparatus of the present invention, the output signal from the input voltage detecting means for detecting the input voltage from the commercial power source and the input current detecting means for detecting the input current from the commercial power source is applied to the load. In an induction heating device provided with a microcomputer for controlling input power by input power adjusting means, adjusted power storage means for storing predetermined adjusted power, and control by the input power adjusting means to stop the input power of the load. Adjustable control means that is variable, and when the input power of the load matches the adjusted power stored in the adjusted power storage means by the adjustment control means, the adjusted power and the input voltage stored in the adjusted power storage means An input current for comparing the output signals of the detection means and the input current detection means to calculate a correction value of the input current from the input current detection means Positive value calculation means, input current correction value storage means for storing the correction value calculated by the input current correction value calculation means, and the input current detection using the correction value stored in the input current correction value storage means Since the microcomputer is further provided with an input current correction means for correcting the output signal from the means, it becomes possible to automatically perform the work of adjusting the input power to the load without using an adjustment tool.

[Brief description of drawings]

FIG. 1 is a block diagram of a system showing an embodiment of the present invention.

FIG. 2 is a block configuration diagram of the system simplified above.

[Explanation of symbols]

 1 Commercial Power Supply 3 Microcomputer 7 Oscillation Coil (Load) 14 Input Voltage Detection Means 16 Input Current Detection Means 17 Input Power Adjustment Means 18 Adjustment Control Means 21 Adjusted Power Storage Means 22 Input Current Correction Value Calculation Means 23 Input Current Correction Value Storage Means 24 Input current correction means

Claims (1)

[Claims] 1. Input power adjusting means for adjusting input power to a load by output signals of an input voltage detecting means for detecting an input voltage from a commercial power source and an input current detecting means for detecting an input current from the commercial power source. In an induction heating apparatus equipped with a microcomputer for controlling, an adjusted power storage means for storing a predetermined adjusted power, an adjustment control means for stopping the control by the input power adjustment means and varying the input power of the load, When the adjustment control means matches the input power of the load with the adjusted power stored in the adjusted power storage means, the adjusted power stored in the adjusted power storage means, the input voltage detection means, and the input current detection means Input current correction value calculation means for calculating the correction value of the input current from the input current detection means by comparing each output signal of Input current correction value storage means for storing the correction value calculated by the current correction value calculation means, and the output signal from the input current detection means is corrected using the correction value stored in the input current correction value storage means. An induction heating device, characterized in that the microcomputer is further provided with an input current correction means.