KR20180044766A - Induction heating cooker - Google Patents

Abstract

The present invention relates to an induction heating cooker which varies a capacitance in each induction fuel intake to suppress heating of a switching element included in each fuel intake, or reduces the difference of resonance frequencies between a plurality of induction fuel intakes to reduce or prevent interference noise. The induction heating cooker of the present invention comprises: at least one driving unit for separately operating at least one induction fuel intake whose capacitance is varied; an input unit for obtaining a set heating power and a set duty, or a heating power stage for each induction fuel intake from a user; and a control unit for separately controlling the driving unit to operate the induction fuel intake with the set heating power and the set duty, or a set heating power and a set duty corresponding to the heating power stage, the control unit confirming a resonance frequency of a single induction fuel intake when one of the induction fuel intakes performs a heating operation and performing a capacitance adjusting process of varying the capacitance of the single induction fuel intake with respect to the confirmed resonance frequency.

Description

Induction Heating Cooker {INDUCTION HEATING COOKER}

The present invention relates to an induction heating cooker, and in particular, by varying the capacitance in each induction cooker, it is possible to suppress the generation of switching elements included in the induction cooker or reduce the difference in resonance frequency between a plurality of induction cookers to reduce interference noise To an induction heating cooker.

The induction heating system is a system for providing cooking heat to a cooking vessel. The induction heating system generates an induction current in a cooking vessel composed of a magnetic body due to a magnetic field generated by supplying a current to a working coil formed inside the body, Induction range, rice cooker, fan, cook top and slow cooker are examples of induction heating cookers.

Among induction heating cookers of the related art, an induction range includes a body having a housing space formed therein, first and second induction furnaces mounted in the housing space to form induction currents below the cooking vessel, And an upper plate portion covering the first and second induction furnaces and displaying a cooking region on the upper side corresponding to the first induction furnace and the second induction furnace, wherein each of the first induction furnace and the second induction furnace has at least one working coil And the induction heating cooker in this specification is mainly described about an induction range.

The resonance frequencies of the first and second induction furnaces are different from each other depending on the setting fire power for each of the first and second induction furnaces and the material, size, and shape of the cooking vessel placed in the cooking zone above the first and second induction furnaces Do. If the cooking vessel is placed in each of the first and second induction furnaces and the first and second induction furnaces are operated simultaneously so that the difference between the resonance frequencies of the first and second induction furnaces is in the audible frequency band (about 2 kHz to 20 kHz) Interference noise is generated. This interference noise makes the user considerably uncomfortable, and may cause the user to doubt the failure of the induction heating cooker.

In order to prevent such interference noise, the prior art has proposed that the first and second induction furnaces are separated by a considerable distance (about 10 cm) or more (hereinafter referred to as "first prior art & (Hereinafter, referred to as "second prior art") in which first and second driving units for controlling each of the two IGBT elements are applied to one induction unit.

In the case of the first prior art, when the main body is standardized to have a constant area (volume) (the area occupied by the main body in the kitchen sink is almost constant) The diameter of the second induction furnace (for example, the working coil) must be reduced, and the first or second induction furnace having such a reduced diameter has a problem that it is difficult to generate a strong thermal power.

Further, in the case of the second conventional technology, the circuit structure of the half bridge type inverter circuit is complicated, and the production cost thereof is also increased.

The present invention suppresses heat generation of a switching element (for example, an IGBT element) included in an induction furnace by varying the capacitance in each induction furnace, reduces a difference in resonance frequency between a plurality of induction furnaces and reduces interference noise The present invention also provides an induction heating cooker for preventing or preventing an induction heating cooker.

In addition, the present invention provides an induction heating control device for controlling duty of a plurality of induction heating furnaces to control duty of a plurality of induction heating furnaces without reducing the set heating amount (set integrated power) of the induction heating furnaces, And it is an object of the present invention to provide a heating cooker.

The present invention also provides a method of controlling a thermal power so that the resonance frequency difference of a plurality of induction heating appliances is not included in an audible frequency band (for example, 2 kHz or less or 20 kHz or more) using the principle that the thermal power and the resonant frequency are inversely proportional to each other. And an object of the present invention is to provide an induction heating cooker that maintains a set heating amount (set integrated power) by adjusting the duty when the thermal power is adjusted while performing the frequency change control.

The induction heating cooker of the present invention includes at least one driver for operating at least one induction furnace in which the capacitance is variable, an input part for acquiring a setting firepower and a set duty or firepower step for each of the at least one induction firepower from the user, And controlling the at least one or more driving units to respectively operate the at least one induction furnace with the set firepower and the set duty or with the set firepower corresponding to the firepower stage and the set duty respectively, When a single induction furnace performs a heating operation, a capacitance adjustment process is performed to confirm the resonance frequency of the single induction furnace and vary the capacitance of the induction furnace on the basis of the identified resonance frequency .

Preferably, the control unit operates the induction furnace of the single number with a minimum thermal power and a full duty, and confirms the resonance frequency of the induction furnace of the single number from the driving unit.

Preferably, the control unit compares the identified resonance frequency with a reference resonance frequency to determine necessity of variable capacitance of the induction unit of the singular number.

The control unit may determine that the capacitance is required to be varied if the identified resonance frequency is greater than the reference resonance frequency, and vary the capacitance of the singulation induction unit.

In addition, the induction heating cooker of the present invention includes a plurality of driving units for respectively operating a plurality of induction cooking hobs having variable capacitances, an input unit for acquiring a setting firepower and a set duty or firepower phase for each of the plurality of induction firepaces from a user, And controls the plurality of driving units to operate the plurality of induction furnaces respectively with the set firepower and the set duty or the set firepower corresponding to the firepower stage and the set duty respectively, , The plurality of induction furnaces are alternately operated with the set firepower and the set duty to confirm the resonance frequencies of the plurality of induction furnaces from the plurality of drivers, respectively, and the difference (absolute value) Of the induction furnace of one of the plurality of induction furnaces And a control unit for performing a capacitance adjustment process for varying the capacitance.

In addition, the controller may compare the difference (absolute value) between the resonance frequencies with a reference frequency for adjusting the capacitance to determine the necessity of the variable capacitance.

If the difference (absolute value) between the resonance frequencies is greater than the reference frequency, the control unit determines that the capacitance is required to be varied, and varies the capacitance of one induction unit of the plurality of induction units desirable.

Preferably, the control unit varies the capacitance of the induction furnace having a large resonance frequency among the resonance frequencies.

It is preferable that the controller stores operation history information indicating whether the number of induction burners or the plurality of induction burners has been judged to be necessary for varying the capacitance.

In addition, the operation history information preferably includes one of a set state and a reset state.

Preferably, the control unit determines a variable necessity of the capacitance when the operation history information is in a reset state, and the control unit sets the operation history information to a set state.

Preferably, the controller varies the capacitances of the at least one induction furnace or the plurality of induction furnaces to a minimum capacitance, and sets the operation history information to a reset state.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a switching device (for example, a switching device, a switching device, etc.) included in an induction furnace by varying the capacitance in each induction furnace without distancing the induction furnace, reducing the diameter of the induction furnace, And IGBT elements) and reduces the difference in resonance frequency between a plurality of induction furnaces, thereby reducing or reducing interference noise.

In addition, the present invention performs duty misregistration control to prevent a plurality of induction burners from simultaneously operating without reducing the set heating amount (set integrated power) of a plurality of induction burners by controlling each thermal power and duty of the induction burners, There is an effect of preventing interference noise.

In addition, the present invention uses the principle that the resonance frequency of the induction unit is inversely proportional to the resonance frequency of the induction unit, so that the interference between the resonance frequencies of the plurality of induction units is not included in the audible frequency band to prevent interference noise, The duty is controlled to maintain the set heating amount.

In addition, the present invention selectively performs the duty shift control or the frequency change control, and compensates the heating loss portion due to the rising time of the thermal power when the operation of the induction furnace is started so that the induction heating furnace outputs the set heating amount It is effective.

According to another aspect of the present invention, there is provided a method of operating an induction furnace during an output operation of an induction furnace, including the steps of simultaneously performing a duty- So that interference noise is prevented.

1 is a configuration diagram of an induction heating cooker according to the present invention.
Fig. 2 is a control operation flow chart performed by the induction heating cooker of Fig. 1; Fig.
3 is a flowchart of a frequency control process included in the control operation of FIG.
4 is a flow chart of a capacitance adjustment process included in the control operation of FIG.
5 is a flow chart of a capacitance adjustment process performed in the frequency control process of FIG.
FIG. 6 is a graph illustrating a heating amount compensation process performed by the induction heating cooker of FIG. 1. FIG.
FIG. 7 is a graph for explaining the operation control process of the induction cookers performed in the frequency control process performed by the induction heating cooker of FIG.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings.

1 is a configuration diagram of an induction heating cooker according to the present invention. The induction heating cooker includes a commercial power supply unit 1 to which commercial AC power is supplied, first to third rectifying units 3-1 to 3-3 to which a commercial AC power is supplied and supply a DC voltage, An input unit 5 for acquiring commands such as start and end of operation, selection or change of firepower (or firepower), selection of a cooking menu, start and end of cooking, and the like, A display unit 7 for displaying a cooking menu, a start and end of cooking, and at least one working coil WC1 and WC2, respectively. The first and second rectifying units 3-1 and 3-2 The first and second induction heating units 8 and 9 are controlled by the control signal of the control unit 20. The first and second induction heating units 8 and 9 operate by induction heating resonance, 1 and the second induction craters (8), (9) And a control unit 20 for controlling the first and second driving units 18 and 19 and the aforementioned components to control the first and second driving units 18 and 19 according to a user's command do. The power supply unit 1, the input unit 5, the display unit 7, the first and second driving units 18 and 19 are well known to those skilled in the art, Explanations are omitted. Although the present invention is explained through the induction heating cooker having the first and second induction cooking utensils 8 and 9, it can also be applied to the induction heating cooker having three or more induction cooking utensils.

The first rectification part 3-1 is composed of a diode bridge BD1 to which commercial AC power is supplied from the power supply part 1, a choke coil L1 and a capacitor C1, and the second rectification part 3-2 Includes a diode bridge BD2 to which commercial AC power from a power supply unit 1 is applied, a choke coil L2 and a capacitor C2. The third rectifying unit 3-3 receives the DC voltage required for the first and second driving units 18 and 19, the input unit 5, the display unit 7, and the control unit 20, Respectively. In the present specification, the first to third rectifying sections 3-1 to 3-3 are collectively referred to as a rectifying section 3. [

The first induction heating furnace 8 includes a first variable capacitance unit which receives a direct current voltage from the first rectification unit 3-1 and whose capacitance is variable, a working coil WC1 connected in parallel to the first variable capacitance unit, And a first switch SW1 connected between the first variable section and the working coil WC1 and the first rectification section 3-1. The first variable capacitance unit includes a first path including a first capacitor C1-1 and a second path connected in parallel to the first path and connected to the first path by a control unit 20 for conducting / 1 relay unit RLY1 and a second capacitor C2-1 connected in series to the first relay unit RLY1. The first variable capacitance unit has a capacitance (minimum capacitance) of only the first capacitor C1-1 when the first relay unit RLY1 is in an OFF state and the first relay unit RLY1 has a capacitance ), A capacitance (maximum capacitance) which is the sum of the capacitance of the first capacitor C1-1 and the capacitance of the second capacitor C1-2 is obtained. Therefore, the resonance frequency of the first induction heating furnace 8 is influenced by the minimum capacitance, the inductance or the maximum capacitance of the working coil WC1 and the inductance of the working coil WC1. Therefore, by varying the capacitance of the first variable capacitance portion The resonance frequency of the first induction crater 8 is also varied.

Also, the second induction burning port 9 is also the same as the first induction burning port 8 A second variable capacitance unit having a capacitance varying with a direct voltage from the second rectification unit 3-2, a working coil WC2 connected in parallel with the second variable capacitance unit, a second variable capacitance unit and a working coil And a second switch SW2 connected between the first rectification part WC2 and the second rectification part 3-2. The second variable capacitance unit includes a first path including a second capacitor C2-1 and a second path connected in parallel to the first path and connected to the first path by a control unit 20 for conducting / 2 relay unit RLY2, and a second capacitor C2-2 connected in series to the second relay unit RLY2. The second variable capacitance unit has a capacitance (minimum capacitance) of only the first capacitor C2-1 when the second relay unit RLY2 is in the blocking state (OFF) and the second relay unit RLY2 has the capacitance ), The capacitance of the sum of the capacitance of the first capacitor C2-1 and the capacitance of the second capacitor C2-2 has the maximum capacitance. Therefore, the resonance frequency of the second induction heating furnace 9 is influenced by the minimum capacitance, the inductance or the maximum capacitance of the working coil WC2 and the inductance of the working coil WC2. Therefore, by varying the capacitance of the second variable capacitance portion The resonance frequency of the second induction furnace 9 also varies.

The minimum capacitance and the maximum capacitance of the first induction furnace 8 may be equal to or different from the minimum and maximum capacitances of the second induction furnace 9, but the same case is exemplified in this embodiment.

If the capacitances of the first and second induction burning openings 8 and 9 are excessively small, the resonance frequencies of the first and second induction burning openings 8 and 9 become high, The first and second switches SW1 and SW2 may be damaged because heat generated by the switches SW1 and SW2 is increased and the resonance voltage is also increased. The minimum capacitance is determined so as to prevent heat generation and damage of the switch SW2. If the capacitances of the first and second induction heating cathodes 8 and 9 are excessively large, the resonance frequency becomes low, and the loss due to the switching loss of the first and second switches SW1 and SW2 Since the first and second switches SW1 and SW2 can be heated more heat by increasing the voltage of the first and second switches SW1 and SW2, Is determined.

The induction heating cooker according to the present invention includes a power source unit 1, a rectifying unit 3, an input unit 5, a display unit 7, first and second induction heating units 8 and 9, and first and second driving units (Not shown) in which a housing space for housing the control unit 20 and the control unit 20 is formed, and a main body And an upper plate (not shown) for displaying a cooking area on the upper plate. The input unit 5 and the display unit 7 are installed on the front surface of the upper plate.

When the control unit 20 performs an operation (output) function for one of the first and second induction burning openings 8 and 9, the same operation as that of the induction heating cooker in the related art The first or second driving unit 18 is controlled so that the induction heating unit selected by the setting firepower (or firepower step) set by the user and the duty (or duty ratio) corresponding to the setting firepower or the setting firepower and the duty set by the user are operated, , And (19). Table 1 below is a data table showing the corresponding relationship between the thermal power level, the thermal power and the duty, and the corresponding relationship of the accumulated power, which is the heating amount according to the thermal power level (thermal power and duty).

Firepower stage One 2 3 4 5 6 7 8 9 10 fire power
(W) 1100 1100 1100 1100 1100 1100 1100 1300 1500 1800 Duty
(Sec) 1.1 / 6 1.6 / 6 2.2 / 6 2.7 / 6 3.8 / 6 4.9 / 6 6/6 6/6 6/6 6/6 Integration
power
(Wh) About 200 About 300 About 400 About 500 About 700 About 900 1100 1300 1500 1800

When only a single induction burner is operated, the control unit 20 controls the first or second driving unit 18, 19 to perform the heating operation according to the thermal power and duty corresponding to each thermal power stage, ). Here, the duty is represented by the on-time (sec) / duty cycle. For example, in 1.1 / 6, the induction crater is turned ON for 1.1 seconds and the induction crater is stopped for 4.9 seconds (6-1.1) OFF, and the accumulated electric power Wh means the amount of heating when heating is performed for one hour to the selected thermal power level, and is calculated as "thermal power (W) x duty ". Also, the controller 20 performs a capacitance adjustment process to prevent the first or second switches SW1 and SW2 from increasing in heat. The capacitance adjustment process is performed by the control unit 20 while maintaining the first and second relay units RLY1 and RLY2 in the cutoff state and operating the first or second induction heating unit 8 or 9 If the identified resonance frequency exceeds the reference resonance frequency Rf for prevention of heat generation, the first or second relay units RLY1 and RLY2 are operated in the conduction state, 2 induction craters (8), (9).

An example of the resonance frequency according to the capacitance variation of the cooking vessel and the first or second induction heating furnace (8), (9) is shown in Table 2 below.

division Firepower stage Step 7 (1100 W) 8 steps (1300W) 9 steps (1500W) 10 steps (1800W) A container application at least
Capacitance 35kHz 34 kHz 32 kHz 31 kHz maximum
Capacitance 30 kHz 29kHx 28kHz 27 kHz B container application at least
Capacitance 43 kHz 41 kHz 40kHz 38 kHz maximum
Capacitance 37 kHz 36 kHz 34 kHz 33 kHz

Here, it is confirmed that the A container and the B container are containers having different electrical characteristics, and that the resonance frequency in the induction furnace having the maximum capacitance in all vessels is reduced by approximately 4 to 6 kHz from the resonance frequency in the induction furnace having the minimum capacitance do. This decrease in the resonance frequency prevents the heat generation of the first and second switches SW1 and SW2 from being intensified.

In addition, the capacitance adjustment process can be applied not only to a single inverter crane operation but also to a plurality of inverter crane operations. For example, the resonance frequencies of the first inverter crater 8 to which the A container is applied and the second inverter crater 9 to which the B container is applied (the first and second inverter craters 8 and 9) Capacitance) are 35 kHz and 7 kHz, respectively, and the difference between the resonance frequencies is 43 kHz and 8 kHz, respectively. However, when the second relay RLY 2 of the second inverter crater 9 is converted into the conduction state at the same thermal power, the resonance frequency of the second inverter crater 9 is reduced to 37 kHz and the first and second inverter craters 8) and (9) is remarkably reduced to 2 kHz, and interference noise is remarkably reduced by the reduction of the difference between these resonance frequencies.

The controller 20 determines the resonance frequencies of the first and / or second induction heating units 8 and 9 while the capacitance is being adjusted and outputs the first and second relay units RLY1 and RLY2 (See Fig. 4) and whether or not the first or second relay unit RLY1 or RLY2 is in a conducting state or a blocking state (see Fig. 5) of the necessity of conduction operation (i.e., a necessity of variable capacitance) And the like.

 The control unit 20 stores the operation history information in an initial state at the time of manufacture of the induction heating cooker or at the end of the control method and stores the operation history information in the reset state only when the operation history information is in the reset state. The resonance frequency of the induction cutters 8 and 9 is checked to determine the necessity of the conduction operation of the first or second relay units RLY1 and RLY2 and the operation history information is set and stored in the set state. If the number of the induction fireballs in operation is kept the same, the control unit 20 determines whether the number of the induction fireballs 8 is larger than the first and / or the second induction fireballs 8 and 9 based on the operation history information (set state) Of the resonance frequency of the resonator. For example, in the case where the number of induction cookers being operated, a single induction cooker in operation is turned off and then turned on again, or the cooking vessel is removed and returned, the first and / or second induction cookers 8, 9) can be confirmed again.

The control unit 20 controls only one of the first or second relay units RLY1 and RLY2 to be in a conductive state or controls the first and second relay units RLY1 and RLY2 to be in a cutoff state do.

Next, when a plurality of inverter craters are to be operated, the control unit 20 performs an interference noise prevention method including a capacitance adjustment process. This interference noise preventing method is a method in which the control unit 20 controls the first and second inverter craters 8 (8) and (9) without operating time overlapping each other with the respective thermal power set in the first and second inverter craters ), And (9), respectively. This duty shift control process operates only the first inverter crater 8 during the duty corresponding to the thermal power of the first inverter crater 8 and the second inverter crater 9 stops operating, The process of operating only the second inverter culvert 9 during the duty corresponding to the thermal power of the second inverter culvert 9 is sequentially repeated after the lapse of the duty corresponding to the thermal power of the inverter.

In addition, in the interference noise prevention method, when the thermal power of the first and second induction burning openings 8 and 9 is lowered, the resonance frequencies of the first and second induction burning openings 8 and 9 become higher, When the thermal power of the second induction burning openings 8 and 9 is increased, the resonance frequency of the first and second induction burning openings 8 and 9 is lowered, 8 and 9 so that the difference between the resonance frequencies of the first and second induction cooking zones 8 and 9 is not included in the audible frequency band .

Examples of the resonance frequency according to the sizes of the cooking pot and the thermal power stages (or thermal power) of the first and second induction cooking openings (8) and (9) are shown in Table 3 below.

division Firepower stage Step 7 (1100 W) 8 steps (1300W) 9 steps (1500W) 10 steps (1800W) When the C container is applied to the first induction furnace (8), the resonance frequency 38.9 kHz 37.2 kHz 35.5 kHz 34 kHz When the D container is applied to the second induction furnace (9), the resonance frequency 33.7 kHz 32.1 kHz 30.5 kHz 29.5 kHz

Also, it is confirmed that the difference between the resonance frequencies is reduced by the frequency change control process in Table 4 below.

fireball Before frequency change control After frequency change control fire power
(W) Duty
(Sec) Integrated power
(Wh) Resonance
frequency
(KHz) fire power
(W) Duty
(Sec) Integrated power
(Wh) Resonance
frequency
(KHz) The first induction crater (8) 1100 W 6/6 1100 38.9 1800 W 3.66 / 6 1099 34 Second induction crater (9) 1100 W 6/6 1100 33.7 1100 W 6/6 1100 33.7 Difference between resonant frequencies 5.2 0.3

In Table 4, the difference between the resonance frequency of the first induction cooking appliance 8 and the resonance frequency of the second induction cooking appliance 9 is 5.2 kHz, and the difference is included in the audible frequency band, It will occur considerably.

The control unit 20 increases the thermal power of the first induction furnace 8 from 1100 W to 1800 W by the frequency change control process and adjusts the duty to be 6.6 to 3.66 so that the accumulated power before the thermal power change and the accumulated power after the thermal power change become the same / 6. By this frequency change control, the difference between the resonance frequency of the first induction cooking appliance 8 and the resonance frequency of the second induction cooking appliance 9 is 0.3 kHz, the difference is not included in the audible frequency band, Hardly occurs.

In the operation of a single induction furnace, only the capacitance adjustment process is used. However, in the operation of the plurality of induction furnaces, the capacitance adjustment process, the frequency change control process, and the duty shift control process included in the interference noise prevention method are the first and second May be performed independently or sequentially according to the set duties for the induction furnaces (8), (9), the difference between the resonant frequencies, etc., and will be described in detail below.

Fig. 2 is a control operation flow chart performed by the induction heating cooker of Fig. 1; Fig. In the start step, the control unit 20 starts the heating operation from the input unit 3 in accordance with the firebox selection, the firepower step and the cooking start input or the operation start input inputted by the user. In the following description, the setting firepower P1 is the setting firepower of the first induction firepot 8 (firepower corresponding to the set firepower phase), the setting firepower P2 is the setting firepower of the second induction firepot 9, The set duty D1 is the set duty of the first induction firepot 8 and the set duty D2 is the set duty of the second induction firepot 9 and the duty Dp is Duty cycle. The firepower P1-1 is an increase fire power of the first induction firepot 8 (a firepower greater than the firepower corresponding to the set firepower phase) and the firepower P2-1 is the increase firepower of the second induction firepot 9 The duty D2-1 is a decreasing duty of the first induction burning port 8 and the duty D2-1 is a decreasing duty of the second induction burning port 9. The duty ratio to be.

In step S1, the control unit 20 determines whether a plurality of induction furnaces are operating according to a user input from the input unit 3. [ If the plurality of induction furnaces, that is, the first and second induction furnaces 8 and 9, are in operation, the process proceeds to step S3, otherwise the process proceeds to step S25.

In step S3, the control unit 20 determines whether the duty shift control can be performed based on the set duty D1 and the set duty D2. If the sum of the set duty D1 and the set duty D2 is less than or equal to the duty cycle Dp, the controller 20 operates the first induction furnace 8 during the set duty D1 within the duty cycle Dp The duty induction control can be performed during the set duty D2 after the set duty D1 and the second induction burner 9 can be operated during the set duty D2. Dp), there is an overlap time between the set duty D1 and the set duty D2. Accordingly, the process goes to step S7.

In step S5, the control unit 20 sets the first and second inductors P1 and P2 to the set duty P1 and P2 set in the first and second induction burning openings 8 and 9, And starts performing the duty shift control for operating the second induction craters 8 and 9, respectively. In this duty shift control, the set duty D2 is turned ON and OFF immediately after the ON and OFF operations of the set duty D1 within the duty cycle Dp It is possible to wait until the next duty cycle and turn on and off the set duty D1 from the start time of one duty cycle Dp and set the set duty D2 at the end of the duty cycle Dp The setting duty D2 is set to ON so that the set duty D1 and the duty D2 are set in an intermediate period in which the set duty D1 and the duty D2 are not overlapped with each other. Both the duty D1 and the duty D2 may be turned off. In the duty shift control, the induction peak to be duty-operated first may be determined according to the user's input order for the first and second induction craters 8 and 9, or may be fixed to the default. For example, when the control unit 20 receives the operation input to the first induction crater 8 after receiving the operation input to the second induction crater 9 from the user first, the first induction crater 8 The duty control for the second induction firepot 9 may be performed first. When the first induction firepot 8 is initially determined to be duty-controlled first, when the control unit 20 performs the duty shift control for the first induction firepot 8 and the second induction firepot 8, The first induction crater 8 can be operated in the duty first.

In step S7, the control unit 20 determines at least one of the set firepower P1 and P2 by adjusting the increase of the firepower P1-1 and P2-1, (D1) and (D2) are set so as to be equal to the set integrated electric power by the set firepower P1 and P2 and the set duty D1 and D2, (D1-1) and (D2-1). In Table 3, the thermal power of the first induction furnace 8 is increased from 1100 W to 1800 W, and the duty is adjusted from 6/6 to 3.66 / 6 such that the set integrated electric power before the thermal power change and the set integrated electric power after the thermal power change are the same So that the set integrated electric power of the first induction cooking appliance 8 is kept constant.

In step S9, the control unit 20 determines whether the duty shift control can be performed based on the reduction duty D1-1 and the duty D2-1. If the sum of the decrease duty D1-1 and the duty D2-1 is less than or equal to the duty cycle Dp, the control unit 20 proceeds to step S11 because the duty shift control can be performed, Since there is an overlap time between the decrement duty D1-1 and the duty D2-1 within the duty cycle Dp, the process goes to step S10.

In step S10, the control unit 20 controls both the first and second relay units RLY1 and RLY2 to have the minimum capacitances of the capacitances of the first and second induction burning openings 8 and 9, , Sets the operation history information in the reset state and stores it, and then proceeds to (A).

In step S11, the control unit 20 determines whether or not the first (first) and second (second) duty cycles are set to the adjusted increase power P-1, And the second inverter craters (8), (9).

In step S13, the control unit 20 determines whether a single induction unit is currently operating. That is, when only a single induction burner operates, the control unit 20 does not need to perform the interference noise preventing method, so the control unit 20 performs step S13. If a single induction burner is currently operating, the process proceeds to step S23. Otherwise, if a plurality of induction burners are operating, the process proceeds to step S15.

In step S15, the control unit 20 receives the cooking vessel inspection result from the first and second driving units 18 and 19 to determine whether the cooking vessel of one or more induction cooking zones has been removed. For this determination, the first and second driving units 18 and 19 perform the cooking vessel inspection using the difference in current value depending on the presence or absence of the first and second cooking vessels, The control unit 20 determines whether or not the cooking vessel placed on the first and second induction cooking hobs 8 and 9 has been removed according to the cooking vessel inspection result. If the cooking vessel has been removed from any one of the first and second induction cooking zones 8 and 9, the process proceeds to step S17, and if not, the process proceeds to step S19.

In step S17, the control unit 20 calculates the removal duration of the cooking container based on the results of the inspection of the cooking vessels from the first and second driving units 18 and 19, (For example, one minute). The first and second driving units 18 and 19 can perform the cooking vessel inspection with a difference in the current value depending on the presence or absence of the cooking vessel for a predetermined period of time (for example, one minute) And the result of the cooking vessel inspection is applied to the control unit 20 repeatedly. If the detachment duration of the cooking container is not less than the reference, the process proceeds to step S21, and if not, the process proceeds to step S3.

In step S19, the control unit 20 determines whether or not the thermal power of one or more induction furnaces has been changed by the user's input from the input unit 5 in a state where the cooking vessel is not detached. If the thermal power for any one of the first and second induction burning openings 8 and 9 is changed, the resonance frequencies of the first and second induction burning openings 8 and 9, It is necessary to determine again whether or not the interference is caused between the first and second antennas. Therefore, the process proceeds to step S3 to perform the interference noise prevention method from the beginning. If the firepower for the first and second induction fire booths 8 and 9 has not been changed, the flow advances to step S5 to perform the duty slip control currently being performed.

In step S21, the control unit 20 controls the first or second driving unit 18 or 19 to cancel the cooking of the induction cooking bowl from which the cooking vessel has been removed, thereby stopping the heating operation.

In step S23, since only one induction burner operates, the control unit 20 terminates the interference noise prevention method, and sets the firepower and the duty of one induction burner in operation to the set firepower P1, P2 and the duty D1 and D2 of the first and second driving units 18 and 19, respectively.

In step S25, the control unit 20 determines whether all of the induction cooking zones have been cooked through the input from the user through the input unit 5 or the control process for the first and second driving units 18 and 19 before . If the first or second induction cooking utensils 8 and 9 are in operation, the process proceeds to (a) to advance the cooking, and if not, the process proceeds to step S27.

In step S27, the control unit 20 controls both the first and second relay units RLY1 and RLY2 so that the capacitances of the first and second induction burning openings 8 and 9 are the minimum capacitances. , Sets the operation history information in the reset state and stores it, and ends the entire control process.

Table 5 below shows the adjustment process of the set firepower and the set duty in the steps (S3) to (S9) and (S11).

fireball Before setting firepower change After changing setting firepower Thermal power (W) Duty (Sec) Integrated power (Wh) Thermal power (W) Duty (Sec) Integrated power (Wh) The first induction crater (8) 1100 W 4.9 / 6 898 1800 W 2.99 / 6 897 Second induction crater (9) 1100 W 4.9 / 6 898 1800 W 2.99 / 6 897

The control unit 20 calculates the sum of the duty (4.9 / 6) of the first induction crater 8 and the duty (4.9 / 6) of the second induction crater 9 as shown in Table 5, Is larger than the duty cycle 6/6, and proceeds to step S7. In step S7, the control unit 20 increases the set firepower of the first and second induction fireposts 8, 9 from 1100 W to 1800 W, changes the set cumulative power 898W before the set firepower change and the set firepower change The duty is adjusted from 4.9 / 6 to 2.99 / 6 so that the set integrated electric power (897W) is the same or the difference is minimized. In step S9, the control unit 20 determines whether the sum of the adjusted decreasing duty (2.99 / 6), (2.99 / 6) of the first and second induction cut-off points 8, 9 is greater than the duty cycle 6 / The control proceeds to step S11 so as to control the first and second induction fire booths 8 and 9 to be shifted to each other with the increased heating power 1800W and the decreasing duty 2.99 / 6.

In Table 5, the duties of the first and second induction firepaces 8 and 9 are overlapped for 3.8 to 4.9 seconds before the setting firepower is changed, and the interference noise is generated during the overlapping time. However, 1 and the second induction firepaces 8 and 9 do not overlap with each other, interference noises do not occur.

In step S7, the control unit 20 increases the setting firepower to the maximum adjustable firepower of the first and second induction fireposts 8, 9, adjusts the set duty, or sequentially sets the firepower to a reference magnitude And adjusts it by decreasing the set duty accordingly.

3 is a flowchart of a frequency control process included in the control operation of FIG.

In step S29, the control unit 20 sets the increase power P1-1, P2-1, and the decrease duty D1-1, D2-1 adjusted in step S7 at step S1 (P1), (P2) and the set duty D1 (D2), which are set in advance, and stores the restored set firepower P1 and P2.

In step S31, the control unit 20 operates alternately with the set fire powers of the plurality of induction furnaces and the set duty to confirm the resonance frequencies of the plurality of induction furnaces, respectively. The control unit 20 drives only the first driving unit 18 to operate only the first induction heating furnace 8 for a predetermined time with the set heating power P1 and the set duty D1 and the first driving unit 18 drives the first induction heating furnace The resonance frequency f1 of the crane 8 is calculated and transmitted to the control unit 20. [ Next, the control unit 20 drives only the second driving unit 19 to operate only the second induction furnace 19 for a predetermined time with the set firepower P2 and the set duty D2, and the second driving unit 19 The resonance frequency f2 of the second induction furnace 19 is calculated and transmitted to the control unit 20. [

In step S33, the control unit 20 calculates a difference (? F) between the resonance frequencies f1 and f2 to determine whether interference noise has occurred or not.

In step S35, the control unit 20 compares the difference (? F) between the resonance frequencies f1 and f2 and the lowest frequency fam (for example, 2 kHz) of the audible frequency range Thereby determining whether interference noise has occurred. If the difference (? F) between the resonance frequencies f1 and f2 is larger than the minimum frequency fam in the audible frequency range, the controller 20 determines that interference noise will occur and outputs , It is determined that no interference noise will be generated, and the process proceeds to step S71.

The control unit 20 proceeds to step (A-1), performs the capacitance adjustment process, and then proceeds to step (A-2) to perform step S37.

In step S37, the control unit 20 compares the resonance frequencies of the plurality of induction furnaces and determines the smallest thermal power Pn and the greatest thermal power Px. The control unit 20 uses the principle that the thermal power decreases as the resonance frequency increases so that the resonance frequency of the first and second induction burning openings 8, The setting force of the induction fire port I is determined as the firepower Pn and the setting firepower of the induction fire port Ix having the smaller resonance frequency is determined as the firepower Px. The set duty and set integrated power of the induction fire In are set to the duty Dn and the set integrated power Wn and the set duty of the induction fireball Ix and the set integrated power to the duty Dx and the set integrated power Wx).

In step S39, the control unit 20 compares the firepower Pn with the maximum firepower Pmax. Here, the maximum firepower Pmax corresponds to the maximum firepower that can be output by the first and second induction fireposts 8, 9. If the firepower Pn is smaller than the maximum firepower Pmax, the process proceeds to step S41. Otherwise, the firepower Pn can not be increased, and thus the process proceeds to step S53.

In step S41, the control unit 20 increases the thermal power Pn by the reference magnitude and calculates and stores the adjusted thermal power Pn.

In step S43, the control unit 20 operates the induction furnace In with the adjusted thermal power Pn and the duty Dn of the induction furnace In to acquire, confirm, and store the resonance frequency fv. At this time, the induction crater Ix does not operate.

In step S45, the control unit 20 calculates a difference (absolute value) [Delta] fv between the resonance frequency fv and the resonance frequency fx of the induction furnace Ix to determine whether interference noise has occurred .

In step S47, the control unit 20 determines whether the calculated difference (absolute value)? Fv is smaller than the difference (absolute value)? F in step S33. If the calculated difference (absolute value)? Fv is smaller than the difference (? F), the process proceeds to step S49 because the process of increasing the thermal power of step S41 is effective, ) Is not effective, the process proceeds to step S51.

In step S49, the control unit 20 compares the calculated difference (absolute value)? Fv with the lowest frequency fam in the audible frequency range to determine whether interference noise has occurred. If the calculated difference (absolute value) [Delta] fv is larger than the lowest frequency fam in the audible frequency range, the control unit 20 proceeds to step S39 to further increase the adjusted firepower Pn since interference noise may occur. , It is determined that no interference noise will be generated, and the process proceeds to step S67.

In step S51, the control unit 20 determines that the thermal power increasing process in step S41 is not effective in step S47, and determines that the adjusted thermal power in step S41 performed before step S47 Pn) is reduced by the reference size and determined as the thermal power of the induction furnace In. The firepower of the induction furnace In thus determined makes the difference (absolute value)? Fv the smallest.

Steps S39 to S49 sequentially increase the thermal power Pn of the induction furnace In by the reference size within the maximum thermal power Pmax to reduce the resonance frequency fv of the induction furnace In . In step S39, the control unit 20 is the same as the above-described step S39 when proceeding from step S37. If the control unit 20 proceeds from step S49, the control unit 20 determines whether or not the adjusted firepower Pn in step S41 The maximum firepower Pmax is compared with the maximum firepower Pmax and then the step S41 is further performed to increase the reference firepipe Pn to the adjusted firepower Pn to increase the firepower Pn of the induction firepot In to the maximum firepower Pmax By the reference size. Further, in step S47, when proceeding from step S37 to step S47, the control unit 20 compares the difference (absolute value)? Fv with the difference (absolute value)? F, In the case of proceeding from the step S49 to the step S47, the difference (? Fv) calculated in the step S45 and the difference (? Fv) calculated and stored in the step S45 before the step S49 Absolute value)? Fv, and performs a process of minimizing the difference (absolute value)? Fv.

The control unit 20 performs the above-described steps S39 to S49 and step S51 to perform the process of minimizing the difference (absolute value)? Fv by the increase in the thermal power (thermal power increase process) do.

In step S53, the control unit 20 compares the thermal power Px with the minimum thermal power Pmin. Here, the minimum thermal power Pmin corresponds to the minimum thermal power that can be output by the first and second induction burning openings 8, 9. If the thermal power Px is larger than the minimum thermal power Pmin, the process proceeds to step S55; otherwise, the process proceeds to step S67.

In step S55, the control unit 20 decreases the thermal power Px by the reference magnitude and calculates and stores the adjusted thermal power Px.

In step S57, the control unit 20 operates the induction cooking pot Ix with the adjusted heating power Px and the duty Dx of the induction cooking pot Ix to acquire, confirm, and store the resonance frequency fw. At this time, the induction furnace In does not operate.

In step S59, the control unit 20 determines whether or not an induction noise fw operated in the step S51 or S37 and a duty Dn operated in the step S37, (Absolute value) DELTA fw between the resonance frequencies fv of the coke In.

In step S61 or step S37, the control unit 20 determines whether the calculated difference (absolute value)? Fw is the minimized difference (absolute value)? Fv calculated in steps S39 to S51, . If the calculated difference (absolute value) [Delta] fw is smaller than the minimized difference (absolute value) [Delta] fv, the process of reducing the thermal power of step S55 is effective, The process of reducing the thermal power of step S55 is not effective, and the process proceeds to step S65.

In step S63, the controller 20 compares the calculated difference (absolute value) [Delta] fw with the lowest frequency fam in the audible frequency range to determine whether interference noise has occurred. If the calculated difference (absolute value) [Delta] fw is greater than the lowest frequency fam in the audible frequency range, the control unit 20 may perform step S53 (step S53) to further reduce the adjusted firepower Px , It is determined that no interference noise will be generated, and the process proceeds to step S67.

In step S65, the control unit 20 determines that the firepower reduction process in step S55 is not effective in step S61 and determines that the adjusted firepower in step S55 performed before step S61 Px) is increased by the reference size to determine the firepower of the induction firepot Ix. The firepower of the induction firepot Ix thus determined makes the difference (absolute value)? Fw smallest.

Steps S53 to S63 sequentially increase the resonance frequency fw of the induction fire Ix by decreasing the thermal power Px of the induction fire Ix sequentially from the minimum thermal power Pmin to the reference magnitude . In the step S51, the control unit 20 is the same as the above-described step S53 when proceeding from the step S53, and when the control unit 20 proceeds from the step S63, the adjusted firepower Px in the step S55 and The minimum firepower Pmin is compared with the firepower Px of the induction firepot Ix and the reference firepower Px is further reduced to the adjusted firepower Px in step S55, By the reference size. In step S61, the control unit 20 compares the difference (absolute value)? Fw and the minimized difference (absolute value)? Fv in the case of proceeding from step S51 to step S61 (Absolute value) Δfw calculated in the step S59 and the step S59 before the process proceeds to the step S63 when the process proceeds from the step S63 to the step S61, (Absolute value)? Fw is compared with the difference (? Fw) to minimize the difference (? Fw).

The control unit 20 performs the above-described steps S53 to S63 and step S65 to perform the process of minimizing the difference (absolute value)? Fv by reducing the thermal power (thermal power reduction process) do.

In step S67, the control unit 20 determines whether the set integrated electric power of the induction firepot In and the set integrated electric power of the induction firepot Ix, which have been subjected to the firepower change processing in steps S37 through S65, The duty Dn of the induction furnace In and the duty Dx of the induction furnace Ix are set such that the set integrated power Wn of the induction furnace In is equal to or close to the set integrated power Wx of the induction furnace Ix Dx) so that the set integrated electric powers of the induction furnace In and Ix are kept constant. If the process proceeds from step S49 to step S67, the duty Dn is adjusted based on the adjusted thermal power Pn of the step S41 performed before the step S49 so as to be equal to the set integrated power Wn The controlled thermal power Pn and duty Dn at this time are referred to as a determined thermal power Pn and duty Dn of the induction fire In and the thermal power Px of the induction fire Ix and the duty Dx are referred to as the determined thermal power Px and duty Dx of the induction fire Ix.

When the process proceeds from the step S63 to the step S67, the duty Dn is adjusted based on the determined thermal power Pn of the induction furnace In in the step S51 so as to be equal to the set integrated power Wn And the duty Dx is adjusted based on the adjusted thermal power Px in the step S57 performed before the step S63 to be equal to the set integrated power Wx. The adjusted duty Dn at this time is referred to as the determined duty Dn of the induction fire In and the adjusted firepot Px and duty Dx of the induction firepot Ix are set to the determined firepower Ix of the induction firepot Ix (Px) and duty (Dx).

When the process proceeds from step S65 to step S67, the duty Dn is adjusted on the basis of the determined thermal power Pn of the induction fire In in step S51 to obtain the set integrated power Wn And the duty Dx is adjusted based on the determined thermal power Px of the induction fire Ix in step S65 to be equal to the set integrated power Wx. The adjusted duty Dn at this time is referred to as a determined duty Dn of the induction fire In and the adjusted duty Dx is referred to as the determined duty Dx of the induction fire Ix.

The control unit 20 calculates and stores the determined thermal power Pn and duty Dn of the induction furnace In and the determined thermal power Px and duty Dx of the induction furnace Ix.

In step S69, the control unit 20 compares the induction fire In and Ix in step S67 with the respective determined firepower Pn and duty Dn, the determined firepower Px and the duty Dx ). To be precise, the control unit 20 sets the first or second induction firepot 8 or 9 corresponding to the induction fire In and Ix determined in step S37 to the determined firepower Pn and duty Dn, and the determined thermal power Px and duty Dx.

In step S71, the control unit 20 operates a plurality of induction fireballs with a set firepower and a duty by the user. That is, the control unit 20 operates the first and second induction fireparks 8 and 9 with the set firepot P1 and P2 and the set duty D1 and D2, And D2 are overlapped with each other for a predetermined time, interference noise is not generated by the judgment in step S35.

The firepower increase process of steps S39 to S51 and the firepower reduction process of steps S53 to S65 may be performed in a changed order. That is, the fire reduction process may be performed first and the fire increase process may be performed later.

In step S35, the control unit 20 performs steps S31, S33, S35, and S71 independently of the duty shift control process or the frequency change control process. If the difference (? F) between the resonance frequencies f1 and f2 is greater than the minimum frequency fam in the audible frequency range, the controller 20 determines that interference noise will occur and performs a duty shift control process A frequency change control process may be performed.

Further, in step S35, the control unit 20 compares the difference (absolute value)? F with the highest frequency of the audible frequency range, and if the difference (absolute value)? F is the highest frequency of the audible frequency range The process proceeds to step S71, and if not, the process may proceed to step (A-1).

In the embodiment of FIG. 3, the controller 20 increases the thermal power of the low induction furnace In of the setting firepower so that the difference (? Fv) and? Fw are below the lowest frequency in the audible frequency range, This process of lowering the firepower of the high induction crater (Ix) is performed. The control unit 20 also sets the firepower of the induction furnace In to be lower than the maximum frequency (e.g., 20 kHz) in the audible frequency range so that the difference (absolute value)? Fv and? Lowering and setting It is also possible to perform the process of increasing the firepower of the induction crater (Ix) with a high firepower.

In the case of the induction heating cooker having three or more induction furnaces, the control and operation principles of the induction furnaces of the two halves of FIG. 3 are the same, but the heating power is adjusted by the number of the additional furnaces, . That is, the thermal power of the induction furnace having the lowest resonance frequency (fmin) among the respective burners is fixed, the thermal power of the remaining induction furnaces is increased by the reference magnitude, and the lowest resonance frequency (fmin) The resonance frequencies of the induction furnaces are compared with each other to perform a firepower increase process for ascertaining whether the difference (absolute value) between the resonance frequencies is within the lowest frequency of the audible frequency range. If the interference noise is not generated during the thermal power increase process, the thermal power reduction process is not performed, and when the interference noise occurs, the thermal power reduction process is performed. In the process of reducing the thermal power, the thermal power of the induction furnace with the lowest resonance frequency (fmin) is adjusted by reducing by the reference size, and the resonance frequencies of the induction furnaces due to the thermal power increasing process and the resonance frequencies of the induction furnace (Absolute value) between the resonance frequencies is within the lowest frequency of the audible frequency range. In addition, a process of adjusting each duty of the induction furnaces is performed so that the integrated power of each induction furnace before the interference noise prevention method is performed is satisfied.

For example, when the induction furnace 1 has the lowest resonance frequency, the induction furnace 3 has the highest resonance frequency, and the induction furnace 2 has the intermediate resonance frequency, the control unit 20 sets the thermal power of the induction furnace 1 fixed (The absolute value) between the resonance frequencies of the induction furnaces 1 to 3 (the difference between the resonance frequency of the induction furnace 1 and the resonance frequency of the induction furnace 2, the induction furnace 1 Between the resonance frequency of the induction furnace 3 and the resonance frequency of the induction furnace 3 is calculated. The control unit 20 determines that the difference between the resonance frequency of the induction furnace 1 and the resonance frequency of the induction furnace 2 is within the lowest frequency of the audible frequency range but the difference between the resonance frequency of the induction furnace 1 and the resonance frequency of the induction furnace 3 is the lowest frequency , The firepower increase process is performed by increasing the firepower of the induction firepower 3 by the reference size. If the interference power of the induction unit 2 and the induction unit 3 is the maximum thermal power, if the interference noise is generated, the thermal power reduction process is performed by reducing the thermal power of the induction unit 1 by the reference magnitude. In this way, the control unit 20 can perform the interference noise prevention method even when a plurality of induction furnaces are provided.

In addition, the control unit 20 may adjust the thermal power of three or more induction furnaces so that the difference between the resonance frequencies of the induction furnaces is greater than or equal to the maximum frequency of the audible frequency range.

4 is a flow chart of a capacitance adjustment process included in the control operation of FIG. The single induction unit in operation is one of the first or second induction unit (8), (9). In this flowchart, the first induction unit (8) is illustrated as being in operation.

In step S25 of FIG. 2, when the first induction cooking appliance 8 is in operation, the process proceeds to step S101 through (a).

In step S101, the control unit 20 controls the first induction crater 8 to operate with the setting firepower and the duty.

In step S103, the control unit 20 determines the state of the stored operation history information (set or reset state). If the operation history information is reset, the process proceeds to step S105. Otherwise, if the operation history information is in the set state The process proceeds to step S113.

In step S105, the control unit 20 sets the operation history information to the set state.

In step S107, the control unit 20 confirms the resonance frequency fc of the first induction heating unit 8, which is the induction heating unit in operation. The control unit 20 operates the first induction crater 8 for a predetermined time by driving only the first driving unit 18 to generate the lowest induction power (for example, 7 stages (1100W) and the full duty D1) The first driving unit 18 calculates the resonance frequency fc of the first induction heating unit 8 and transmits the calculated resonance frequency fc to the control unit 20. As can be seen from Table 2, since the resonance frequency of the first induction furnace 8 at the lowest power is higher than the resonance frequency of the first induction furnace 8 at the maximum power, the first switch SW1) is the most severe. Therefore, it is preferable that step S107 is performed on the basis of the lowest fire power considering that the user can use the lowest fire power.

In step S109, the control unit 20 compares the received resonance frequency fc with a reference resonance frequency Rf for preventing heat generation. Here, the reference resonance frequency Rf corresponds to a frequency (for example, 40 kHz) at which excessive heat generation of the first switch SW1 occurs. If the received resonance frequency fc is larger than the reference resonance frequency Rf, the controller 20 determines that the heat generation of the first switch SW1 may be excessive, Otherwise, the conduction operation control (variable capacitance) of the first relay unit RLY1 is unnecessary, and the process proceeds to step S113.

In step S111, the control unit 20 operates the first relay unit RLY1, which is a relay included in the first induction heating unit 8, which is the induction heating unit in operation, to be in a conductive state to change the capacitance of the first induction heating unit 8 To the maximum capacitance.

In step S113, the control unit 20 controls the first induction crater 8 to operate in accordance with the set firepower and the duty.

In step S115, the control unit 20 determines whether the cooking of the first induction cooking appliance 8, which is the induction cooking appliance in operation, is completed. If the cooking of the first induction cooking appliance 8 is completed, the process proceeds to step (C) and step S27 is performed. Otherwise, the process proceeds to step (b) and the process proceeds to step S1.

The order of execution of steps S105 and S107 described above may be changed.

In step S115, the process proceeds to step (b). In step S1, if only the first induction firepot 8, which is a single induction firepot, is in operation, steps S25, If the process proceeds to step S103, the control unit 20 checks the stored operation history information, and proceeds to step S113 because the operation history information is set, thereby preventing the steps S105 to S111 from being unnecessarily repeated do.

5 is a flow chart of a capacitance adjustment process performed in the frequency control process of FIG.

The control unit 20 performs step S35 and proceeds to step S201 through step (A-1).

In step S201, the control unit 20 checks the state of the stored operation history information. If the operation history information is in the reset state, the controller 20 proceeds to step S203 to determine whether the capacitance adjustment is necessary. Otherwise, State (i.e., when the capacitance adjustment is unnecessary or the capacitance is already adjusted), the process proceeds to step S37 via (A-2).

In step S203, the control unit 20 compares the difference (? F) between the resonance frequencies f1 and f2 calculated in step S33 and the reference frequency fac for capacitance adjustment do. As described above, since the resonance frequency is reduced by a variable range (for example, 4 to 6 kHz) of the resonance frequency by the capacitance adjustment process, the difference (absolute value) between the estimated resonance frequencies f1 and f2 The control unit 20 can perform the capacitance adjustment process. Here, the reference frequency fac for adjusting the capacitance is set to have a frequency included in this variable range, and is set to, for example, 5 kHz. If the difference (? F) between the estimated resonance frequencies f1 and f2 is equal to or greater than the reference frequency fac, the process proceeds to step S205; otherwise, the process proceeds to step S37).

In step S205, the control unit 20 sets the operation history information to the set state and stores it.

In step S207, the control unit 20 compares the resonance frequency f1 of the first induction cooking aperture 8 with the resonance frequency f2 of the second induction cooking aperture 9, Increases from the minimum capacitance to the maximum capacitance. If the resonance frequency f1 of the first induction cooking appliance 8 is equal to or greater than the resonance frequency f2 of the second induction cooking appliance 9, the process proceeds to step S209, and if not, the process proceeds to step S211 . However, when the difference (? F) between the resonance frequencies f1 and f2 is equal to or greater than the variable range in step S203, the process proceeds to step S207, so that the resonance frequencies f1 and f2 ) Are not the same.

In step S209, the control unit 20 controls the first relay unit RLY1 to be in a conduction state to reduce the resonance frequency f1 of the first induction cooking appliance 8, The capacitance is changed to the maximum capacitance, and the process proceeds to step S29 via (A).

The control unit 20 controls the second relay unit RLY2 to be in a conductive state to reduce the resonance frequency f2 of the second induction heating unit 9 in step S211, The capacitance is changed to the maximum capacitance, and the process proceeds to step S29 via (A).

The above-described step S205 may be performed after the execution of steps S209 and S211, respectively, unlike the order shown in Fig.

3 and 5, the present invention firstly performs a capacitance adjustment process between (A-1) and (A-2) when interference noise is generated in step S35, It is exemplified that the frequency control process is performed in steps S37 to S69 after decreasing the difference between the resonant frequencies between the induction coves 8 and 9 by the variable range described above by the capacitance adjustment However, the order of control of the capacitance adjustment process and the frequency control process may be changed.

FIG. 6 is a graph illustrating a heating amount compensation process performed by the induction heating cooker of FIG. 1. FIG. The control unit 20 controls the first and second driving units 18 and 19 so that the first and second driving units 18 and 19 are driven to the first and second induction heating units 8 and 9 The thermal power is applied in accordance with the set duty (duty ON and OFF). Ideally, the thermal power must immediately increase from 0 to the set firepower W1 at the time t1 when the duty is ON, but the firepower is increased by the time constant value of the circuit components in the cooking vessel or induction heating cooker, A rising time gradually increases from 0 to the set firepower W1. The rising time (t1-t2) in Fig. 6 causes a loss of the heating amount (PL-hatched portion). That is, since the loss of the heating amount occurs at each duty-ON time while performing the interference noise prevention method, a difference is generated by the loss heating amount PL between the set integrated electric power and the actual integrated electric power.

In order to solve this problem, the controller 20 makes the actual thermal power OFF after a predetermined time elapses from the duty OFF time included in the set duty, i.e., the first and second induction burners are compensated for more than the set duty And the heating amount is compensated. Specifically, the control unit 20 obtains the current value from the first and second drivers 18 and 19, and calculates the time (time t2) required to rise to the target current value corresponding to the setting power W1, The slope of the current rising curve is calculated by confirming the current value in a predetermined time unit from the time t1 to the time t2 and the slope of the current rising curve is integrated by integrating the slope of the current rising curve PL) is calculated. Next, the control unit 20 calculates the compensation time by dividing the loss heating amount PL by the current setting firepot W1. 6, the control unit 20 maintains the thermal power for the compensation time at the duty-off time (time t3) of the set duty, and maintains the thermal power at the time t4, Off signal to the first and second drivers 18 and 19, respectively. That is, the control unit 20 adds up the compensation time to the set duty and sets the duty cycle of the duty cycle (time t3-time t1) + compensation time for the first and second drivers 18 and 19 The first and second induction furnaces 18 and 19 are controlled such that the on duty time of the set duty (time (duty)) of the set duty is applied to the first and second driving units 18 and 19, (t3) - time (t1)) + compensation time). For example, if the on-duty time is 3 seconds and the compensation time is 0.2 second, the control unit 20 generates a control signal including duty 3.2 / 6 and outputs the control signal to the first and second driving units 18, (19), thereby compensating for the loss heat amount.

As described above, the control unit 20 compensates the heating amount by using the current values from the first and second driving units 18 and 19, but may use other measurement values (for example, voltage values) The heating amount compensation may be performed.

Alternatively, the induction heating cooker has a cumulative power meter for measuring the cumulative power at the first and second induction cooking zones 8 and 9, and the control unit 20 acquires the cumulative power from the cumulative power meter. The control unit 20 stores the maximum power and the accumulated power data in the entire duty cycle 6/6 and receives the accumulated power due to the maximum power and the set duty from the integrated power meter, The compensation time may be calculated by dividing the difference (integrated power difference) between the applied accumulated powers by the maximum thermal power. Further, the control unit 20 stores controllable firepower and all accumulated power data in the entire duty 6/6, receives the integrated firepower and the accumulated electric power due to the set duty from the integrated electric power meter, responds to the stored firepower The compensation time may be calculated by dividing the difference between the integrated electric power and the applied integrated electric power by the setting firepower.

FIG. 7 is a graph for explaining a process of controlling the operation of the induction furnaces performed in the frequency control process performed by the induction heating cooker of FIG.

7 (a) is a thermal power graph S1 of the first induction furnace 8 operated with the total duty 6/6 and the thermal power Wa, and FIG. 7 (b) FIG. 7C is a thermal power graph S3 of the first induction heating apparatus 8 modified according to the present invention. FIG. 7C is a thermal power graph S2 of the second induction heating apparatus 9 which is ON.

The first induction furnace 8 is controlled by the thermal power Wa and the second induction furnace 9 is controlled by the frequency control process so that the thermal power of the first induction furnace 8 and / Is operated with the thermal power Wb, no interference noise is generated. However, due to the rising time (from time t10 to time t11), the thermal power of the second induction furnace 9 gradually increases from 0 to the thermal power Wb. That is, during the rising time, the resonance frequency of the second induction burning port 9 is changed, so that the difference (absolute value) between the resonance frequencies of the first and second induction burning ports 8 and 9 is in the audible frequency range Interference noise is included.

In order to prevent such an interference noise, as shown in FIG. 7 (c), when each duty of a plurality of induction burners is overlapped during operation of duty shift control or frequency change control, The frequency change due to the rising time of each induction furnace is caused to coincide with the time point when the off state is changed from the OFF state to the duty ON state so that there is little difference between the resonance frequencies of the induction furnaces, . If the first induction firepot 8 is the total duty (6/6) and the second induction firepot 9 is the set duty, the controller 20 controls the second induction firepot 9 before the duty on The first and second induction burning openings 8 and 9 are turned on at a time point when the second induction burning openings 9 are turned on, So that the interference noise due to the change in the frequency of the rising time can be prevented.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims. It is to be understood that modifications are possible and that such modifications are within the scope of the claims.

1: Power supply unit 3:
5: Input section 7: Display section
8, 9: first and second induction furnaces 18, 19: first and second driving parts
20: control unit SW1, SW2: first and second switches
RLY1, RLY2: The first and second relay units

Claims (22)

At least one or more drive units for respectively operating at least one induction furnace in which the capacitance is variable;
An input unit for obtaining a setting firepower and a set duty or a firepower step for each of the at least one induction firepaces from a user;
Wherein each of the at least one induction fire extinguishers is operated by the set fire power and the set duty or the set fire power and the set duty corresponding to the fire power stage respectively by controlling each of the at least one drive units, And a control unit for checking the resonance frequency of the induction unit of the single number when the induction unit performs the heating operation and performing a capacitance adjustment process of varying the capacitance of the induction unit of the single number based on the identified resonance frequency Features an induction heating cooker. The method according to claim 1,
Wherein the controller operates the induction cooker having the single number with a minimum thermal power and a total duty, and confirms the resonance frequency of the induction cooker having the number of the induction cookers from the driving unit. 3. The method of claim 2,
Wherein the control unit compares the identified resonance frequency with a reference resonance frequency to determine necessity of variable capacitance of the induction unit of the singular number. The method of claim 3,
Wherein the control unit determines that the capacitance is required to be varied if the identified resonance frequency is greater than the reference resonance frequency, and varies the capacitance of the singulated induction cooking cavity. A plurality of driving units for respectively operating a plurality of induction furnaces with variable capacitances;
An input unit for obtaining a setting firepower and a set duty or a firepower step for each of the plurality of induction firepaces from a user;
And controls the plurality of driving units to respectively operate the plurality of induction firepaces with the set firepower and the set duty or the set firepower corresponding to the firepower stage and the set duty, respectively, when the plurality of induction firepaces perform the heating operation , The plurality of induction furnaces are alternately operated with the set firepower and the set duty to confirm the resonance frequencies of the plurality of induction furnaces respectively from the plurality of drivers, and the difference (absolute value) between the resonance frequencies is referred to And a controller for performing a capacitance adjustment process for varying the capacitance of one of the plurality of induction cooking zones. 6. The method of claim 5,
Wherein the control unit compares a difference (absolute value) between the resonance frequencies and a reference frequency for capacitance adjustment to determine a necessity of variable capacitance. The method according to claim 6,
Wherein the controller determines that the capacitance is required to be varied when the difference (absolute value) between the resonance frequencies is greater than the reference frequency, and varies the capacitance of one induction furnace of the plurality of induction furnaces Induction heating cooker. 8. The method of claim 7,
Wherein the control unit varies the capacitance of the induction cooking zone having a large resonance frequency among the resonance frequencies. The method according to claim 3 or 4 or 6 to 8,
Wherein the controller stores operation history information indicating whether or not the number of induction cookers or the plurality of induction cookers has been judged as requiring a variable capacitance. 10. The method of claim 9,
Wherein the operation history information includes one of a set state and a reset state. 11. The method of claim 10,
Wherein the control unit determines a necessity of variable capacitance when the operation history information is in a reset state, and the control unit sets the operation history information to a set state. 11. The method of claim 10,
Wherein the control unit varies the capacitances of the at least one induction cooktop or the plurality of induction cooktop to a minimum capacitance and sets the operation history information to a reset state. 9. The method according to any one of claims 5 to 8,
Wherein when the simultaneous heating operation of the plurality of induction burners is performed, the duty cycle control is performed on the plurality of induction burners by comparing the set duty of each of the plurality of induction burners with the duty cycle before the capacitance adjusting process And a control unit for controlling the heating unit. 14. The method of claim 13,
Wherein the control unit performs the duty shift control when a sum of set durations of the plurality of induction cookers is less than or equal to the duty cycle. 14. The method of claim 13,
If the sum of the set duties of the plurality of induction culverts is greater than the duty cycle, the controller decreases the set duty of at least one induction culprit among the plurality of induction cultrits and increases the set fire power of the one induction culminator , And the set integrated power of said one induction cooking appliance is kept constant. 16. The method of claim 15,
Wherein the controller compares the duty cycle of the plurality of induction cookers with the set duty of the plurality of induction cookers and the reduced set duty. 17. The method of claim 16,
When the sum of the set duty of the plurality of induction fireballs and the reduced set duty is less than or equal to the duty cycle, the control unit sets the set duty of the plurality of induction fireballs, the reduced set duty, And performs the duty shift control. 17. The method of claim 16,
Wherein the control unit varies the capacitance of the plurality of induction furnaces to a minimum capacitance when the sum of the set duty of the plurality of induction furnaces and the reduced set duty is greater than the duty cycle, Wherein the at least one of the at least two heating elements is at least one heating element. 19. The method of claim 18,
Wherein the control unit performs a frequency changing process of adjusting at least one of the setting power of the plurality of induction furnaces so that the difference (absolute value) between the resonance frequencies is out of the audible frequency range. Cooker. 20. The method of claim 19,
Wherein the controller is configured to control the increasing process and the smallest resonance frequency for the setting force of the induction furnace having the largest resonance frequency so that the difference (absolute value) between the resonance frequencies is less than or equal to the lowest frequency of the audible frequency range And a reduction process for setting firepower of the induction furnace. 20. The method of claim 19,
Wherein the control unit is configured to perform a reduction process on the setting force of the induction furnace having the largest resonance frequency and a process for decreasing the minimum resonance frequency to a value equal to or larger than the maximum resonance frequency Wherein the at least one induction heating cooker performs at least one of an increasing process for setting firepower of the induction furnace having the induction heating cooker. 20. The method of claim 19,
Wherein the control unit adjusts a setting duty of the induction cooking zone in which the setting thermal power is adjusted so that the set integrated power of the induction cooking zone in which the setting thermal power is adjusted is kept constant.

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