JP3054840B2 - Multi-port induction heating cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-port induction heating cooker having a plurality of heating coils, wherein the total input power does not exceed a predetermined value when the plurality of heating coils operate simultaneously. .

[0002]

2. Description of the Related Art In recent years, many multi-port induction heating cookers provided with a high-output heating coil and a plurality of inverters for driving the heating coil have been provided. There has been proposed a multi-port induction heating cooker that limits the total input power so that the total input power does not exceed a predetermined value when the heating coils are simultaneously used.

For example, as shown in Japanese Patent Application Laid-Open No. 58-68888, a specific power supply is operated in conjunction with a power switch of another inverter or in conjunction with a reference voltage of a pulse width modulation circuit of another inverter. A method of changing the reference voltage of the pulse width modulation circuit of the inverter and suppressing the conduction time of the switching element to suppress the driving power of a specific heating coil, or as disclosed in Japanese Utility Model Application Laid-Open No. Sho 62-153789. A method of providing a total input power detecting means for detecting a total of input power supplied to all inverters so that a detected value does not exceed a predetermined value;
As disclosed in Japanese Unexamined Patent Publication No. 270291, there has been a method of calculating the total sum of the set powers of the input power setting means by a calculating means and changing the power supplied to each heating coil based on the calculation result.

[0004]

However, in the configuration disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 58-68888, the input power of a particular inverter is kept constant when a plurality of inverters are operated at the same time. Is limited, the limit level of the input power is not determined by monitoring the input power, and is a method of simply changing the reference voltage level of the pulse width modulation circuit to suppress the conduction time of the switching element.
If the shape or material of the load changes, the limit level will fluctuate, so the maximum input cannot be set accurately, and the user must manually allocate the maximum power to each heating coil during simultaneous operation. There were challenges.

In the configuration disclosed in Japanese Utility Model Laid-Open Publication No. Sho 62-153789, a total current detection circuit is required. For example, if a current transformer is used as a total current monitor component, the detection current becomes large. If accurate detection is to be performed, the shape of the current transformer becomes large and expensive, and the number of parts increases because the number of detection circuits increases.

Further, the configuration disclosed in Japanese Patent Laid-Open No. 2-270291 requires arithmetic means for calculating the sum of the set power of the setting means, and the configuration of the power determining means to be supplied to each heating source is complicated. In addition, since the amount of power supplied to each heating source is determined by the power determining means, there is a problem that if the power determining means fails, all the heating sources may be unusable.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and does not complicate the control circuit and has an inexpensive configuration so that when a plurality of heating coils operate simultaneously, the sum of the input currents does not flow more than a predetermined amount. To automatically set the maximum possible supply power to each heating coil, and to provide a multi-port induction heating cooker in which a failure of the control means of one heating coil hardly affects the operation of another heating coil. This is the first purpose.

A second object of the present invention is to further improve the cooking performance by automatically controlling the temperature of the load while changing the heating output in accordance with the temperature of the load in a specific heating coil. When other heating sources are operated at the same time and the output increases in the course of the above-mentioned automatic temperature control operation, the other is automatically controlled so that the total input current to the equipment does not exceed the limit instantaneously. To limit the power supply to the heating coil.

A third object is that, in addition to the second object, when automatic temperature control is performed by changing the output in a specific heating coil, the opportunity to limit the power supply to other heating coils is minimized. In order not to reduce usability.

A fourth object is to provide the maximum possible supply to each heating coil automatically when a plurality of heating coils are operated simultaneously so that the sum of the input currents does not flow more than a predetermined value. When setting the power, the power suppression level of the frequency converter in which the input power is suppressed is changed in multiple stages according to the power set value of the other frequency converter, and the degree of power limitation is reduced as much as possible. The purpose is to reduce adverse effects on cooking.

A fifth object is to inform the user of the presence or absence of the power limitation and to prevent the user from having a distrust of the difference between the setting content and the actual heating power.

[0012]

The present invention in order to achieve the first object, there is a solution to a means for] comprises a plurality of frequency translation devices, each including a control unit for controlling the heating coil and the switching element and the switching element, wherein each the control unit, setting the output of the frequency converter in accordance with the signal <br/> No. of input means to input a start-stop instruction or the output level of the change instruction of the frequency conversion device is performed by operation of the user and output setting means for, on of the switching element based on an output signal of said output setting means, an output control means for controlling the output of the controlled off the frequency converter, control of the respective
Among control unit, at least one control unit, depending on the setting state of the output signal or the output setting means of said input means, "1" state or "0" electrical binary signal indicating the state
Manner and having an output setting judgment means for outputting the insulation signal transmitting means for transmitting by an insulating state, at least one other control <br/> control of the control unit comprising the output setting discrimination means The unit inputs the binary signal output from the output setting determination unit via the insulation signal transmission unit, and limits an output of the frequency conversion device to which the control unit belongs according to a state of the binary signal. This is a configuration having output limiting means.

According to a second aspect of the present invention, there is provided the present invention, wherein at least one of the control units having the output setting determining means directly or indirectly controls the temperature of the load. , A temperature control means for varying the output setting of the output control means in response to a signal from the temperature sensor and changing the output of the frequency converter to control the temperature of the load, and a signal from the output setting means. Output setting method selecting means for switching between output setting according to the output setting according to the signal from the temperature control means, and when the output setting by the temperature control means is selected,
The output setting determination unit fixes the binary signal output to the insulation signal transmission unit to a predetermined state, and limits the output of the frequency conversion device to which the control unit that receives the output signal of the insulation signal transmission unit belongs. Configuration.

According to a third aspect of the present invention, there is provided the present invention, wherein at least one of the control units having the output setting determining means directly or indirectly controls the temperature of the load. Temperature control means for varying the output of the frequency conversion device in accordance with a signal from the temperature sensor to control the temperature of the load; and an output setting and a temperature control in accordance with a signal from the output setting means. Output setting method selecting means for switching output setting according to a signal from the means, the output setting determining means, when the output setting by the temperature control means is selected by the output setting method selecting means, The binary signal is output to an insulation signal transmitting means in accordance with an output setting state set by the temperature control means.

According to a fourth aspect of the present invention, a control unit of at least one frequency converter includes an output signal or an output signal of an input means. Output setting discriminating means for outputting a plurality of sets of binary signals indicating a "1" state or a "0" state to a corresponding plurality of insulating signal transmitting means in accordance with a setting state of the setting means or the temperature control means, At least one other control unit of the control unit including the output setting determination unit inputs a plurality of sets of the binary signals output by the output setting determination unit via the plurality of insulation signal transmission units, and According to another aspect of the present invention, there is provided an output limiting means for varying an output limiting level of the frequency converter to which the control unit belongs in accordance with a combination of a plurality of sets of states of the binary signal.

According to a fifth aspect of the present invention, there is provided the present invention, wherein the input signal or the output of the insulated signal transmitting means is provided by any one of the first, second, third and fourth aspects. The display mode of at least one display unit is changed according to the state of the signal.

[0017]

According to a first aspect of the present invention, there is provided an induction heating cooker comprising: a plurality of frequency converters each including a heating coil, a switching element, and a control unit for controlling the switching element. Since the transmission and reception of signals with other frequency converters for output control during simultaneous operation are performed via insulating signal transmission means and using simple binary signals, one Even if a component of the frequency conversion device, for example, a switching element, a component of the output control means such as a microcomputer, or a component constituting the output setting means fails and a specific heating coil cannot be used, other heating coils are not used. Works fine. Alternatively, the influence on the operation of other heating coils is reduced.

Further , at least one of the above-mentioned respective control units is provided.
One control unit transmits a binary signal indicating a “1” state or a “0” state in an electrically insulated state according to the output signal of the input unit or the setting state of the output setting unit .
Output setting discriminating means for outputting to the insulation signal transmitting means for the other, the other of the control unit comprising the output setting discriminating means
At least one control unit inputs a binary signal output from the output setting determination unit via the insulation signal transmission unit, and outputs an output of a frequency conversion device to which the control unit belongs according to a state of the binary signal. Since the control unit having the output limiting unit has the output limiting unit, the control unit including the output limiting unit monitors the output setting state of the control unit including the output setting determining unit, and monitors the output setting state of the specific frequency converter set by itself. The output can be controlled, and when a plurality of heating sources are operated simultaneously, the sum of the input currents is equal to or greater than a predetermined value smaller than the sum of the maximum input currents when each heating source is operated independently. Will not flow.

That is, if the output setting in the output setting means of the control section to which the output setting determining means belongs is equal to or more than a predetermined value, for example, the output setting determining means outputs a "1" state signal to the insulation signal transmitting means, and If the value is smaller than the value, a signal in the “0” state is output. If the signal corresponding to the signal in the “1” state is input via the insulating signal transmitting means, the output limiting means may output itself. If the output setting of the control unit is limited to a predetermined value that is smaller than the maximum possible set value and the signal corresponding to the signal in the “0” state is input, the restriction is released. Regardless of what setting is made by operating the input means at the same time, the sum of the output powers of the two is equal to or less than the sum of the output value set by the control unit to which the output setting determination means belongs and the output value limited by the control unit to which the output limiting means belongs. Suppressed, both Will be limited to less than the small becomes a value than the sum of the maximum output power that can be set to Germany.

Further, as described above, the output setting discriminating means for outputting its own output setting status, and the specific output setting discriminating means for inputting a signal from the output signal of the other output setting discriminating means via the insulation signal transmitting means. Since the signal transmission / reception with the means is performed by the binary signal indicating the "1" state or the "0" state, the insulation signal transmission means can be easily constituted by a phototriac or a phototransistor, and generated from the heating coil. This prevents a malfunction due to high-frequency noise.

Further, in the means for achieving the second object, at least one or more control units include a temperature sensor for directly detecting the load temperature or indirectly detecting the temperature of the load via a top plate or the like. It has a temperature control means for inputting a signal from this temperature sensor and varying the output of the frequency conversion device in accordance with this signal to control the temperature of the load. Change the output and perform automatic cooking with optimal heat. In addition, since output setting method selecting means for switching between the output setting by the output setting means and the output setting by the temperature control means is provided, the output adjustment by the input means and the execution of the automatic cooking by the temperature control means are appropriately performed according to the cooking content. Choose one. Further, when the output setting by the temperature control means is selected,
The output setting determination means outputs to the insulation signal transmission means 2
The value signal is fixed to a predetermined state, and the fixed signal is detected by the output limiting means of at least one other control unit via the insulating signal transmitting means, and the output to a specific heating coil is limited in advance. Even if the temperature control means instantaneously increases the power supplied to the heating coil in order to maintain the load temperature or rapidly raise the load temperature, the total sum of the input currents to the equipment is a predetermined value. Will not be exceeded.

Further, in the means for achieving the third object, at least one of the plurality of control units includes an insulation signal transmitting unit according to the output setting by the output setting unit belonging to the control unit. Output setting discriminating means for sending a binary signal to the output means, and output setting method selecting means for switching between output setting by the output setting means and output setting by the temperature control means.
The output setting determining means, when the output setting by the temperature control means is selected, outputs the binary signal to an insulation signal transmitting means according to the setting of the output set by the temperature control means, Since the output limiting means of at least one other control unit is configured to input the binary signal via the insulation signal transmitting means and limit the output of a specific heating coil according to the value, at least one In the control unit having the output limiting unit, an output setting state of the control unit having at least one other temperature control unit and the output setting determining unit to the heating coil is selected by the temperature control unit. The output of the heating coil set by itself is controlled while monitoring whether or not the heating coil is set.

Therefore, in a multi-port induction heating cooker including a frequency conversion device having a control unit capable of selecting the output setting by the user and the automatic output setting by the temperature control means,
Regardless of which output setting is selected, when a plurality of heating coils are driven and the sum of the input powers may become too large, at least one control unit restricts the output level of a specific heating coil. Therefore, it is possible to prevent the total sum of the input currents from increasing, and also in this case, the output setting by the temperature control means is not limited, but the output of another control unit is suppressed. The automatic temperature control function by the temperature control means is not reduced.

Further, when the output setting by the temperature control means is selected, the output value of the other heating coil is not always limited, but the content of the binary signal is changed according to the output value set by the temperature control means. As a result, the output value of the other heating coil can be limited only when a large output is set by the temperature control means, thereby reducing the opportunity for limiting the output.

Further, in the means for achieving the fourth object, the control unit in at least one of the frequency converters may include a plurality of control units in accordance with an output signal of the input means or a setting state of the output setting means or the temperature control means. Since output setting discriminating means for outputting a set of binary signals indicating the "1" state or the "0" state to the corresponding plurality of insulating signal transmitting means is provided, the output signal is transmitted via the insulating signal transmitting means according to the output setting state. And a plurality of sets of binary signals to be output. In addition, at least one control unit other than the control unit including the output setting determination unit inputs a plurality of sets of binary signals output from the output setting determination unit via a plurality of insulation signal transmission units. Since there is output limiting means for varying the output limiting level of the frequency converter to which the control unit belongs according to the combination of the states of the set of binary signals, the output limiting level of the frequency converter is determined by the output setting determination. A plurality of stages can be set according to the output setting state of the control unit having the means, and the total input power can be finely limited.

[0026] In the means for achieving the fifth object, at least one of the following is provided in accordance with the state of the input signal or the output signal of the insulation signal transmitting means, which corresponds to whether or not the heating power of the specific heating coil is limited. Since the display mode of the two display means is changed, the user can know that the heating power of the specific heating coil is smaller than the heating power set by the user, and the heating power set at the time of cooking does not come out, and the equipment is not operated. It is possible to prevent a situation in which the user assumes that the device has failed. Further, since the input signal and the output signal of the insulation signal transmission means are binary signals, it is possible to change the display mode of the display means in accordance with the state with a very simple circuit configuration.

[0027]

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG.

FIG. 1 is a circuit block diagram of a multi-mouth cooker having two heating coils and a common heater, a nichrome heater, in the same housing. A full-wave rectifier 3 is connected to a 200 V commercial power supply 1 via a fuse 2, and its DC output terminal has an inverter 4 as one of frequency converters.
And the maximum power consumption of the inverter 4 is 2 k
W. The inverter 4 includes a main circuit 5 for applying a large current or a high voltage and a control unit 11a. The main circuit 5 includes a filter circuit including a choke coil 6 and a capacitor 7, a heating coil 8, a resonance capacitor 9, and a transistor. It is composed of a resonance circuit consisting of ten. The control unit 11a is a circuit block that outputs a signal for driving the transistor 10, and includes an output control unit 12 and an output setting unit 1.
The current transformer 16 monitors the input current and controls the on / off of the transistor 10. Then, the output limiting unit 15 outputs a signal to the output setting unit 13 according to the ON / OFF of the phototransistor 37 and the output signal of the output setting unit 21 of the control unit 11b.

Similarly, the commercial power supply 1
Is connected to the input terminal of the full-wave rectifier 24, and the output terminal is connected to the inverter 25. The maximum power consumption of the inverter 25 is 2 kW. The inverter 25 includes a main circuit 26 and a control unit 32. The main circuit 26 includes a choke coil 27, a capacitor 28, a heating coil 29, a resonance capacitor 30, and a transistor 31. The control unit 32 is a circuit block that outputs a signal for driving the transistor 31 and includes an output control unit 33, an output setting unit 34, an input unit 35, and an output setting determination unit 36, and monitors an input current by a current transformer 38. While controlling the transistor 31 on and off. The output setting judging means 36 outputs an on / off signal to the phototransistor 37 according to the input signal from the output setting means 34.

A series circuit of a nichrome heater 17 and a triac 18 having a maximum power consumption of 1.2 kW is connected to the commercial power supply 1, and an output terminal of a phototriac coupler 19 is connected to a gate of the triac 18. The control unit 11b is an input unit 22 for inputting a command by key operation.
An output setting means 21 for setting the output of the nichrome heater 17 in accordance with the signal; and a drive signal output to the diode portion of the input terminal of the phototriac coupler 19 in accordance with the output of the output setting means 21 to output a triac 18 Is constituted by output control means 20 for driving.

The control unit 11a and the control unit 11b
DC power is supplied from the DC power supply 9 and the DC power supply circuit 40, and is constituted by a single microcomputer and its peripheral circuits, and the emitter potential of the transistor 10 is set to the common potential. The control unit 32 is supplied with DC power by a transformer 41 and a DC power supply circuit 42, and is configured by a microcomputer different from those constituting the control unit 11a and the control unit 11b and its peripheral circuits, and changes the emitter potential of the transistor 31 to the common potential. And

The operation of the induction cooking device configured as described above will be described. When the user presses the heating key of the input means 14, the output setting means 13 detects this and outputs a reference signal corresponding to the maximum output, ie, 2 kW, to the output control means 12. In the present embodiment, the microcomputer executes these operations, detects the occurrence of the ON state of the heating key, and reads the corresponding digital reference signal from the internal storage unit. The output control means 12 has a comparison unit, and the microcomputer is provided with a comparison function, and compares the reference signal with data obtained by A / D conversion of a detection output of the current transformer 16 to perform control. Output the signal to the output port. In the output control means 12, the signal output from the microcomputer is converted into an analog signal, and based on the signal, a peripheral circuit also functions to perform pulse width control and output between the base and the emitter of the transistor 10. The high-frequency resonance current of the heating coil 8 and the resonance capacitor 9 changes according to the pulse width of the drive signal of the transistor 10, and the high-frequency output changes. In this case, the reference signal corresponds to the maximum output. Therefore, the pulse width becomes maximum and the output of the inverter 4 becomes maximum, that is, 2 kW.

It should be noted that the output setting means 13 is the output limiting means 1
5, the nichrome heater 17 and the heating coil 29 are not driven at that time, so that the state of the input signal from the output limiting means 15 is "0" and the output setting means 13 is the input means. The output of the heating coil 8 is determined according to the setting of 14.

Next, when the user presses the output change key of the input means 14 to minimize the output setting, the output setting means 13 incorporated in the microcomputer reads the corresponding reference signal from the internal storage unit and outputs the reference signal. Control means 12
, The pulse width of the drive signal of the transistor 10 is minimized and the output of the inverter 4 is minimized in the same manner as described above.

Then, when the heating key of the input means 22 is pressed, the output setting means 21 incorporated in the microcomputer used in the control section 11a reads the maximum set value from the storage section and corresponds to the output control means 20. Output a signal. Since the method of controlling the power supplied to the nichrome heater 17 is so-called duty control that changes the on / off energization ratio, the output control means 20 applies a continuous drive signal to the input of the phototriac coupler 19, and the triac 18 is continuously turned on. The output of the nichrome heater 17 is controlled to the maximum output value. When the output setting key of the input means 22 is pressed to minimize the output setting, the output setting means 2
1 reads the minimum set value from the storage unit and outputs
Therefore, the output control means 20 outputs a duty signal having an on / off ratio corresponding to the minimum output to the input section of the phototriac coupler 19. As a result, the triac 18 repeatedly turns on and off at the on / off ratio to supply the minimum power to the nichrome heater 17.

When the nichrome heater 17 is driven, the output setting means 21 controls the control unit 1 regardless of whether the output setting is the maximum setting or other than the maximum setting.
A signal whose state is "1" is output to the output setting means 13 of 1a.

Further, when the heating key of the input means 35 is depressed, the output setting means 34 incorporated in the microcomputer which is a component of the control section 32 reads the maximum set value from the storage section. Output the corresponding signal. The output control means 33 performs pulse width control based on the signal to change the drive time width of the transistor 31,
Heating coil 29 and resonance capacitor 30 of main circuit 26
The frequency and the current value of the resonance current generated in the resonance circuit are changed, and the high-frequency output is controlled to the maximum set value, that is, 2 kW while monitoring the input current with the current transformer 38. This operation is performed by the main circuit 5 and the control unit 11 described above.
This is the same as the operation in a.

When the output setting key of the input means 35 is depressed to minimize the output setting, the output setting means 34 incorporated in the microcomputer reads the corresponding reference signal from the internal storage section and sends it to the output control means 33. As a result, the pulse width of the drive signal for the transistor 31 is minimized in the same manner as described above, and the output of the main circuit 26 is minimized.

When the output setting means 34 sets the output of the main circuit 26 to the maximum output, the output setting discriminating means 36 discriminates this and applies a forward current to the diode at the input of the phototransistor 37, and its output side Are turned on by driving the transistor section of FIG. The output limiting unit 15 also receives a signal indicating whether or not the nichrome heater 17 is in a driven state from the output setting unit 21, detects that the phototransistor 37 is turned on, and simultaneously drives the nichrome heater 17 simultaneously. Control unit 1 only when
The signal of the state "1" is output to the output setting means 13 of 1a. When the output setting means 13 provided in the microcomputer receives the signal of the state "1", the output setting means 13 reads the set value corresponding to 1.6 kW from the storage section and outputs the value.
2 so that the output control means 12
By reducing the drive pulse width of 0 and increasing the oscillation frequency, the maximum setting output of the heating coil 8 is suppressed from 2 kW to 1.6 kW.

After that, the driving of the nichrome heater 17 is stopped and the output signal from the output setting means 21 to the output control means 15 becomes "0", the driving of the heating coil 29 is stopped, or the heating coil 29 is stopped. Is set to an output of 1.6 kW or less, and the output setting determining means 36
When this is detected and the driving of the phototransistor 37 is stopped, the output limiting means 15 determines this and sets the state of the output signal to the output setting means 13 to “0”. The restriction on the output of the coil 8 is released, and the output of the heating coil 8 is set as set by the input means 14.

As described above, according to the present embodiment, output 1.
When the 2 kW nichrome heater 17 is driven and the output of the main circuit 26 that supplies the high-frequency current to the heating coil 29 is set to the power exceeding the maximum output setting of 2 kW or 1.6 kW, the main driving the heating coil 8 Circuit 5
Is automatically suppressed to 1.6 kW, so that when the heating coil 8, the nichrome heater 17, and the heating coil 29 are simultaneously driven, the total power does not exceed 4.8 kW. In this embodiment, since the input voltage is 200 V, the maximum value of the total input current is 24 amps. For example, if a home power distribution line or a power supply breaker with a current rating of 30 amps is used, 6 amps can be reliably applied to the rating. Therefore, there is no possibility that the total input current exceeds its rating.

Since the output of the nichrome heater 17 is controlled by duty control, even if the output setting is reduced, the operation stop period becomes longer and the average input power becomes smaller. It is the same as the output setting. In the present embodiment, the nichrome heater 17 is configured to send an output signal to the output limiting means 15 according to the presence or absence of driving regardless of the low output setting or the large output setting. There is no inconvenience that the current exceeds a predetermined value.

When the driving of the nichrome heater 17 is stopped, the driving of the heating coil 29 is stopped, or the output setting of the heating coil 29 is set to an output of 1.6 kW or less, the automatic operation is performed. The restriction of the output of the heating coil 8 is released, and the output of the heating coil 8 can be set according to the setting of the input means 14, so that the chance of the output being restricted can be reduced.

The phototransistor 37 controls the circuit blocks of the control units 11a and 11b and the control unit 3.
Since the two circuit blocks are separated and the power supply voltage to the control unit is separately supplied by the transformer 39 and the transformer 41, for example, the transistor 31 is broken down due to a failure and the fuse 23 is opened. However, since the heating coil 8 and the nichrome heater 17 operate normally without affecting the operation of the inverter 4, there is no disadvantage that all the components fail and cooking cannot be performed at all.

The output setting judging means 36 outputs a so-called binary signal indicating whether the phototransistor 37 is driven or not, that is, whether the output signal is "1" or "0". Since the transistor 37 is configured to determine whether the transistor 37 is on or off, a malfunction does not easily occur due to noise, and a microcomputer that is a component of the control unit 32 and a microcomputer that is a component of the control unit 11a and the control unit 11b. Is used, the circuit configuration can be made extremely simple and the number of parts can be reduced.

Embodiment 2 Hereinafter, Embodiment 2 of the present invention will be described with reference to FIG.

In FIG. 2, a full-wave rectifier 45 is connected to a 200 V commercial power supply 43 via a fuse 44, and a main circuit 46 of an inverter having a maximum power consumption of 3.2 kW is connected to its DC output terminal. In addition, the commercial power supply 43
Is similarly connected via a fuse 47 to a full-wave rectifier 48 and a main circuit 49 of an inverter having a maximum power consumption of 2 kW. The main circuit 46 and the main circuit 49 are the same as the main circuit 5 or the main circuit 26 in the first embodiment, and are circuit blocks including a heating coil, a resonance capacitor, a filter circuit, and a semiconductor switching element. The output of the transformer 70 is sent to the output control means 51 of the control unit 68, and the output of the current transformer 71 is sent to the output control means 62 of the control unit 69.

The difference from the first embodiment is that the main circuit 4
6 is that a thermistor 67 is provided in a control section 68 for controlling the semiconductor switching element of No. 6. The thermistor 67 is pressed against a load mounting plate provided in the vicinity of the heating coil and indirectly detects the temperature of the load pan, or is disposed directly in contact with the load pan and directly detects the temperature of the load pan. The thermistor 67 is connected to the temperature detecting means 50, and the output of the temperature detecting means 50 is sent to the temperature control means 52.

The input means 55 includes the output setting means 5
A temperature setting key 58 and a temperature adjustment selection key 59 are provided in addition to the heating key 56 and the output setting key 57 connected to 4. The signal received by the temperature setting key 58 is input to the temperature control means 52, and the signal received by the temperature adjustment selection key 59 is input to the output setting method selection means 53. The output setting method selecting means 53 also includes an output setting means 54.
And the output signal of the temperature control means 52 is input to send a signal to the output control means 51, and the output control means 51 controls the output of the main circuit 46 based on the signal. The output setting method selecting means 53 sends a signal to the output setting judging means 60, and the output setting judging means 60 drives the diode at the input part of the phototransistor 61 based on the signal.

Inverters 4 and 2 whose maximum power consumption is 2 kW
The control unit 69 that drives the fifth semiconductor switching element has the same configuration as the control unit 11a of the first embodiment, and the detection signal of the current transformer 71 is also connected to the output control unit 62 as in the first embodiment. However, in this embodiment, since the nichrome heater 17 in the first embodiment is omitted, the output restricting means 63 sends a signal to the output setting means 64 only in accordance with ON / OFF of the phototransistor 61.

The operation of the multi-port induction heating cooker configured as described above will be described below. When the heating key 56 is pressed, the output setting means 54 detects this and outputs a reference signal for setting the output of the main circuit 46 to the maximum setting of 3.2 kW to the output setting method selecting means 53. The output setting method selecting means 53 selects this reference signal and outputs it.
Output to The output control means 51 compares the reference signal with the detection signal of the current transformer 70 and controls the output of the main circuit 46 to the maximum setting. When the output setting key 57 is pressed to change the output setting, a reference signal corresponding to the changed setting is output from the output setting means 54 to the output setting method selecting means 53, and the output setting method selecting means 53 Is output to the output control means 51, so that the output of the main circuit 46 is changed to the newly set output in the same manner as described above.

Next, when the temperature adjustment selection key 59 is pressed, the output setting method selection means 53 selects the reference signal output from the temperature control means 52 and outputs it to the output control means 51. When the temperature setting key 58 is not depressed, the temperature control means 52 internally sets a specific reference temperature (for example, 180 ° C.), and the temperature of the load pan detected by the thermistor 67 and the temperature detection means 50 and the above-mentioned temperature. The reference temperature is periodically compared to determine an optimum output so that the load temperature reaches the reference temperature first, and the reference level corresponding to the output is periodically output to the output setting method selecting means 53. . That is, when the difference between the load temperature and the reference temperature is large, heating is performed with a large output, and when the difference between the load temperature and the reference temperature is reduced, output control is performed such as reducing the output so as not to cause so-called overshoot.

When the output control by the temperature control means 52 is selected by the temperature adjustment selection key 59 and the temperature setting key 58 (for example, 200 ° C.) is pressed,
The temperature control unit 52 replaces the specific reference temperature (for example, 180 ° C.) set inside with the temperature (for example, 200 ° C.) corresponding to the pressed temperature setting key 58. Are periodically output to the output setting method selecting means 53 so that the signal arrives quickly.

When the temperature control selection key 59 is pressed to select the output setting of the temperature control means 52, or when the temperature control selection key 59 is not pressed, the output setting means 54 Is greater than the maximum setting of 3.2 kW or 1.6 kW,
The output setting determination means 60 detects this and drives the phototransistor 61. When the phototransistor 61 is turned on, the output limiting means 63 outputs a signal to the output setting means 64 to suppress the maximum output of the main circuit 49 or the output exceeding 1.6 kW to 1.6 kW.

As described above, according to the present embodiment, when the temperature adjustment selection key 59 is pressed, the output of the main circuit 46 is varied according to the current load temperature, and the target temperature is quickly overshot again. Can be reached. When the other main circuits 49 are operated at the same time, the maximum power consumption of the main circuit 49 is automatically set to 1.
Since the power is suppressed to 6 kW, the total power consumption is suppressed to 4.8 kW even when the temperature control means 52 is operating and the output of the main circuit 46 is set to the maximum setting to rapidly increase the load temperature. be able to. Therefore, since the input voltage is 200 V, the maximum value of the input current is 24 amps, and the current capacity of the distribution line or the breaker can be suppressed.

Embodiment 3 Hereinafter, Embodiment 3 of the present invention will be described with reference to FIG.

In FIG. 3, a control section 72 corresponds to the control section 68 of FIG. 2 in the second embodiment. In FIG. 2, the output setting discriminating means 60 directly discriminates the output setting contents of the output setting means 54, and Although the transistor 61 was driven, in FIG. 3, the output setting method selecting means 53 outputs one of the output signals of the temperature control means 52 and the output setting means 54 in response to a signal from the temperature adjustment selecting key 59, that is, The output setting of the main circuit 46 of the inverter is selected, and the output setting determining means 6 is selected in accordance with the selected setting.
0 determines the combination of the driving states of the two phototransistors 61a and 61b.

Further, instead of the output limiting means 63 of FIG.
Output limiting means 76 is provided which receives the output signal 1b and sends a signal to the output setting means 64 in accordance with the combination of the signals. The output limiting unit 76 also outputs a signal to the display circuit 73, and the display circuit 73 drives the light emitting diode 74 according to the signal. The control section 75 drives the main circuit 49 of the inverter, and corresponds to the control section 69 in FIG. Note that, in FIG. 3, components or circuit blocks denoted by the same reference numerals as those in FIG. 2 perform substantially the same functions, and description thereof will be omitted.

The operation of the induction cooking device configured as described above will be described below.

When the temperature adjustment selection key 59 is not pressed, the activation of the main circuit 46 or an output setting command is input by the heating key 56 or the output setting key 57, and the output setting means 54 sets the output accordingly. After this set value is selected by the output setting method selecting means 53,
It is sent to the output control means 51 and also sent to the output setting discriminating means 60. The output setting determining means 60 drives only the phototransistor 61a when the output setting value is 2.9 kW to 3.0 kW. When the output set value is 3.0 kW to 3.1 kW, only the phototransistor 61b is driven, and the output set value is 3.1 kW.
When the power is 3.2 kW from W, the phototransistor 6
Both 1a and 61b are driven.

When only the phototransistor 61a is driven, the output limiting means 76 outputs the output setting command from the output setting means 64 to the output control means 62 when the output setting command exceeding 1.9 kW is input to the input means 65. The output set value is limited to 1.9 kW, and 1.9
When an output setting command of kW or less is input, the output setting value according to the command is output to the output control means 62. When only the phototransistor 61b is driven, the output restricting means 76 outputs 1.7 signals from the input means 65.
When an output setting command exceeding kW is input, the output setting value output from the output setting means 64 to the output control means 62 is limited to 1.7 kW. When input, the output setting value according to the instruction is output to the output control means 62. further,
When both of the phototransistors 61a and 61b are driven, the output limiting means 76 outputs the output setting command from the output setting means 64 to the output control means 62 when the input setting command of the input means 65 exceeds 1.6 kW. Output setting value is limited to 1.6 kW, and 1.6
When an output setting command of kW or less is input, the output setting value according to the command is output to the output control means 62.

That is, when the total of the set output values set by the user or set by the temperature control means exceeds 4.8 kW, the total of the actual output power is limited to 4.8 kW, and the set output value is set. Is less than or equal to 4.8 kW, an output according to each setting can be obtained.

When one of the phototransistors 61a and 61b is driven, the output limiting means 76
A predetermined signal is output to the display circuit 73. The display circuit 73 detects this and drives the light emitting diode 74, and the light emitting diode 74 is turned on.

When the temperature adjustment selection key 59 is pressed, the output setting method selecting means 53 selects the output set value of the temperature control means 52 and sends it to the output control means 51 and the output setting discriminating means 60. The output setting determining means 60 determines the output setting value set by the temperature control means 52 in place of the output setting value of the output setting means 54 when the temperature adjustment key 59 is not pressed, and 6
1a and the driving state of the phototransistor 61b are changed,
The output limiting means 76 limits the output value set by the output setting means 64 according to the combination of the driving states,
A predetermined signal is output to the display circuit 73.

As described above, according to the present embodiment, the main circuit 46 of the inverter and the main circuit 49 of the inverter are simultaneously operated, and the control unit 72 sets the output by the heating key 56 and the output setting key 57. In any case, or when the output has been set by the temperature adjustment selection key 59 and the temperature setting key 58, the output setting discriminating means 60 for monitoring the current output setting value of the main circuit 46 is provided. Temperature control means 52 for automatic temperature control as well as output control by operation.
However, even if the main circuit 46 repeats a large output or a small output state according to the load amount or the temperature, the output of the other main circuit 49 that is simultaneously operated according to the output set value is automatically automatically generated each time. Because of the suppression, it is possible to prevent the total input power from instantaneously exceeding the rating of the breaker of the distribution line or the switchboard. When the power consumption of the main circuit 46 is small, the output restriction of the main circuit 49 is automatically and instantaneously released. When the output is restricted, the main circuit 46 is controlled according to the output set value of the main circuit 46. Since the maximum output limit value of the circuit 49 is set in a plurality of stages, the output limit level may be small, and the influence on cooking can be relatively reduced.

When the output is determined by the output setting discriminating means 60, the light emitting diode 74 is turned on, so that the output is reduced by the user, and the reason is to suppress the total input power. Can be recognized, and the risk of being mistaken for a device failure can be avoided.

In the first embodiment, the nichrome heater 1
7, the state of the output signal of the output limiting means 15 changes depending on whether or not the nichrome heater 1 is driven.
The state of the output signal of the output limiting means 15 may be changed only in the state of the output signal of the phototransistor 37 irrespective of the presence or absence of the driving of the signal 7. Also, for example, the control unit 11
The same configuration as that of the first embodiment can be obtained by configuring the common potential of b to be the same as that of the control unit 32, and reflecting the presence or absence of driving of the nichrome heater 17 on the output of the output setting determination unit 36. The effect is obtained. The configuration of the main circuit 5 or the main circuit 26 of the inverter is not limited to that shown in FIG. 1, but is a two-push push-pull type that operates with a constant frequency and a variable drive time ratio between the two. And the like, and may be a converter instead of an inverter, and the type of the frequency converter can be appropriately selected.

[0068]

As is apparent from the above description, the present invention relates to a heating coil, a switching element and the switching element.
A plurality of frequency converters each including a control unit for controlling the element , wherein each of the control units is performed by a user operation.
Command or output signal of the frequency converter
According to the signal of the input means for inputting the bell change command,
Output setting means for setting the output of the frequency conversion device,
The switching element based on the output signal of the output setting means;
On and off to control the output of the frequency converter
Output control means, and a small number of
At least one control unit is configured to electrically isolate the binary signal indicating the “1” state or the “0” state according to the output signal of the input unit or the setting state of the output setting unit .
Comprising an output setting judgment means for outputting the insulation signal transmitting means for transmitting comprises the output setting determination hand stage the
At least one other control section of the control unit inputs the binary signal output from the output setting discrimination means via said insulating signal transmission means, the control unit in accordance with the state of the binary signal It has output limiting means for limiting the output of the frequency converter to which it belongs, so if a plurality of frequency converters are operated at the same time and the total input power may exceed a predetermined value, a specific frequency is automatically The output of the converter can be suppressed, and the total input current can be prevented from exceeding the rating of the breaker of the distribution line or switchboard. Further, since the control units of the different frequency converters transmit and receive the binary signals via the insulating signal transmitting means, the frequency converters are less susceptible to the high-frequency noise generated by the frequency converters, and are less likely to malfunction.
In addition, since the circuit configuration is simplified, and even if one of the frequency converters fails, it is easy to prevent the other from being affected, the disadvantage that all the heat sources cannot be used occurs. Can be prevented.

Further, the present invention includes the output setting method selecting means for switching between the output setting by the output setting means and the output setting by the temperature control means. Therefore, when the output setting by the temperature control means is selected, the load is set. The automatic cooking can be performed with an optimum heating power while automatically changing the output to the maximum or the minimum output while monitoring the temperature of the temperature, and the binary signal output to the insulation signal transmission means by the output control means is transmitted to a predetermined level. Since the configuration is fixed to the state, the maximum output to another specific heating coil is limited in advance, and the temperature control means instantaneously increases the power supplied to the heating coil to maintain the temperature of the load. In this case, the sum of the input currents to the devices does not exceed a predetermined value.

Further, according to the present invention, in a plurality of frequency converters, at least one or more frequency converters include output setting determining means for determining output setting contents by output setting means included in the control unit, and output setting means by output setting means. And an output setting method selecting means for switching the output setting by the temperature control means. When the output setting by the temperature control means is selected, the insulation is performed according to the setting of the output set by the temperature control means. The binary signal is output to the signal transmitting means, and the at least one other output control means inputs the binary signal through the insulating signal transmitting means, so that the output is automatically set by the user or automatically by the temperature control means. In any case at the time of output setting, if there is a possibility that the sum of the input powers becomes too large when a plurality of heating coils are driven, Both of the output control means can limit the output level of the heating coil whose output is controlled by itself so that the sum of the input currents does not increase. In that case, too, the output setting by the temperature control means can be performed. Is not limited, so that it is possible to prevent the automatic temperature control by the temperature control means from being affected, and if the output decreases during the automatic temperature control, the output of another frequency converter is immediately Since the suppression is released, a decrease in cooking performance due to the output limitation can be minimized.

Further, according to the present invention, at least one control unit indicates a plurality of sets of "1" states or "0" states according to the output signal of the input means or the setting state of the output setting means or the temperature control means. Output setting discriminating means for outputting the value signal to the corresponding plurality of insulation signal transmitting means, and at least one of the control units other than the control unit having the output setting discriminating means.
One control unit inputs a plurality of sets of the binary signals via the plurality of insulation signal transmission units, and limits the output level of the frequency conversion device to which the control unit belongs to a plurality of stages according to a combination of the states. Since the output limiting means is provided, even when a plurality of frequency converters are operated simultaneously, the output of a specific frequency converter can be automatically limited so that the sum of the input power is equal to or less than a predetermined value, and the output is limited. The output of the frequency conversion device to be performed can be varied according to the output level of another frequency conversion device to minimize the limit level and suppress the degree of reduction in cooking performance.

Further, according to the present invention, the display mode of at least one display means is changed in accordance with the state of the input signal or the output signal of the insulation signal transmission means. It is possible to recognize that the heat power is smaller than the set heat power, and it is possible to prevent a situation in which the heat power set at the time of cooking does not come out and the device is assumed to be out of order. Further, since the input signal and the output signal of the insulation signal transmitting means are constituted by binary signals or a combination thereof, the input signal and the output signal are hardly affected by noise and the like, and the circuit structure of the display means for changing the display mode is simplified. be able to.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit of a multi-port induction heating cooker according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit of a multi-port induction heating cooker according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a circuit of a multi-port induction heating cooker according to a third embodiment of the present invention.

[Explanation of symbols]

 4, 25 Inverter (frequency conversion device) 8, 29 Heating coil 10, 31 Transistor (switching element) 11a, 32 Control unit 12, 33 Output control means 13, 34 Output setting means 14, 35 Input means 15 Output limiting means 36 Output Setting discriminating means 37, 61 Phototransistor (insulating signal transmitting means) 46, 49 Main circuit 55, 65 Input means 67 Thermistor (temperature sensor) 68, 69, 72, 75 Controller 74 Light emitting diode (display means)

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Fujii 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-53-90034 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H05B 6/12

Claims (5)

(57) [Claims] [Claim 1 further comprising a plurality of frequency translation devices, each including a control unit for controlling the heating coil and the switching element and the switching element, the control unit of the each of start of the frequency conversion device is performed by operation of the user and output setting means for setting an output of the frequency converter in accordance with a signal input means to input a stop instruction or the output level of the change instruction, on of the switching element based on an output signal of said output setting means, off Output control means for controlling and controlling the output of the frequency conversion device , wherein each of the control units
Among the at least one control unit , according to the output signal of the input means or the setting state of the output setting means,
A binary signal indicating the “1” state or the “0” state is electrically
Comprising an output setting judgment means for outputting the insulation signal transmitting means for transmitting by an insulating state, at least one other control section of the control unit comprising the output setting discrimination means, said insulating signal A multi-input device having input limiting means for inputting the binary signal output from the output setting determining means via a transmitting means and limiting the output of the frequency conversion device to which the control unit belongs according to the state of the binary signal. Mouth induction heating cooker. At least one of the control units including the output setting determining means includes a temperature sensor for directly or indirectly detecting a load temperature, and an output of the output control means in response to a signal from the temperature sensor. Temperature control means for controlling the load temperature by changing the output of the frequency conversion device by changing the setting; and an output for switching between an output setting according to a signal from the output setting means and an output setting according to a signal from the temperature control means. When the output setting by the temperature control unit is selected, the output setting determination unit fixes the binary signal output to the insulation signal transmission unit to a predetermined state, and The multi-port induction heating cooker according to claim 1, wherein the output of the frequency conversion device to which the control unit that receives the output signal of the insulation signal transmission unit belongs is limited. At least one of the control units including the output setting determining means includes a temperature sensor for directly or indirectly detecting the temperature of the load, and an output of the frequency conversion device according to a signal from the temperature sensor. Temperature control means for varying the load and controlling the temperature of the load, and an output setting method selection means for switching between an output setting according to a signal from the output setting means and an output setting according to a signal from the temperature control means, The output setting determining means, when the output setting by the temperature control means is selected by the output setting method selecting means, outputs the signal to the insulation signal transmitting means in accordance with the output setting state set by the temperature control means. 2. The multi-port induction heating cooker according to claim 1, which outputs a value signal. 4. A control unit in at least one frequency conversion device indicates a plurality of “1” states or “0” states according to an output signal of an input unit or a setting state of an output setting unit or a temperature control unit. Output setting determining means for outputting a binary signal to a corresponding plurality of insulation signal transmitting means; and at least one other control section including the output setting determining means includes the plurality of insulation signal transmitting means. A plurality of sets of the binary signals output from the output setting determination means via the output setting discriminating means, and an output limiting level of the frequency conversion device to which the control unit belongs according to a combination of states of the plurality of sets of the binary signals The multi-port induction heating cooker according to claim 1 or 3, further comprising an output restricting means for varying the temperature. 5. The display mode of at least one display means is changed according to the state of an input signal or an output signal of the insulation signal transmission means.
The multi-port induction heating cooker according to claim 4.