JP2001015262A - Cooking apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a control based on the sensing result in a stable condition by heightening the sensing accuracy of a current sensing means and a voltage sensing means. SOLUTION: A current of known level is sensed by a current sensing circuit 32 through a current transformer 31 while the input voltage of known level is sensed by a voltage sensing circuit 34 through a step-down transformer 17, and at the stage before product shipment, the sensing values of current and voltage are stored in a non-volatile memory 38 as the reference current value and reference voltage value, respectively. A control unit 36 calculates the current and voltage values sensed by the sensing circuits 32 and 34, respectively, during the cooking operation on the basis of the stored reference values. At this time of calculation, the power supply frequency sensed by a frequency signal generating circuit 35 and the temp. sensed by a temp. sensing circuit 37 are taken into account.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking device provided with a heating means driven by a commercial AC power supply.

[0002]

In a heating cooker, output control (including power cutoff control) and overcurrent protection control of a load such as a heating means are performed based on a current detected by a current transformer or the like. What is performed is provided, and in addition, it is also performed to detect fluctuations in the power supply voltage and thereby control the output of the heating means. However, in the conventional current detecting means and voltage detecting means,
It is inevitable that the detection current and the detection voltage fluctuate due to a change over time in the circuit constant, and it is difficult to perform an accurate detection operation.

[0003] In recent years, for example, in microwave ovens, it has been demanded to increase the heating output (high-frequency output) as much as possible in order to improve the cooking speed. In this case, the outlet capacity and breaker capacity of the household wiring are generally set to 15 A, and therefore, the maximum rated current of the microwave oven is set to a state as large as possible without exceeding this. Become. However, in practice, the input current of the microwave oven may fluctuate greatly due to fluctuations in the power supply voltage, changes in the ambient temperature, etc. Therefore, the maximum rated current is set to a value that allows for a sufficient margin for 15 A. (For example, around 13A), which has been one of the causes that hinders improvement in cooking speed. In order to cope with such a situation, it is conceivable to perform control to detect an input current through the current detection means and increase the output of the heating means through an inverter circuit or the like when the input current has a margin. However, as described above, in a situation where it is difficult to perform an accurate current detection operation by the current detection means, it is very difficult to perform such control, and there is a situation that the heating output cannot be sufficiently increased. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a first object of the present invention is to improve the accuracy of detection by current detection means and to perform control based on the detected current in a stable state. A second object of the present invention is to provide a heating cooker capable of improving the detection accuracy of an input voltage from a commercial AC power supply in addition to the detection accuracy of a current detection unit. Another object of the present invention is to provide a heating cooker capable of performing control based on a detected voltage in a stable state.

[0005]

According to a first aspect of the present invention, there is provided a heating cooker having a heating means driven by a commercial AC power supply for performing a cooking operation. Current detecting means for detecting a current flowing through a portion, storage means for storing in advance a detection value when a current of a known level is detected by the current detecting means as a reference current value, and the current detecting means during a cooking operation And a current calculation means for calculating a current value detected by the storage means based on the reference current value stored in the storage means.

According to this configuration, even when the current value detected by the current detecting means varies during the cooking operation due to a change over time of the circuit constant or the like, the current value detected by the current detecting means remains unchanged. Is calculated based on the reference current value stored in the storage means in advance (that is, a detection value when a current of a known level is detected by the current detection means), the detection accuracy by the current detection means is improved. Thus, control based on the detected current can be performed in a stable state.

In this case, as in the invention described in claim 2,
The current detection means and the storage means may be arranged on the same substrate or a plurality of substrates which cannot be easily separated. According to this configuration, there is an advantage that the operation of storing the reference current value in the storage unit can be performed not in the assembling process of the heating cooker but in, for example, an inspection process at the time of manufacturing a substrate. The reference current value can be easily stored as compared with the case where the reference current value is stored during the assembling process or the repair and replacement. Further, when a failure occurs in one or both of the current detection means and the storage means, it is only necessary to replace the entirety thereof.
The work for storing the reference current value, that is, the troublesome work of requiring a device for generating a predetermined current is not required, and the repair and replacement thereof can be easily performed.

According to a third aspect of the present invention, a signal generating means for generating a frequency signal indicating the frequency of a commercial AC power supply is provided, and the storage means stores a reference current value and a reference current value when the reference current value is detected. The power supply frequency information is stored in advance, and the current calculating means is provided, if the power supply frequency indicated by the frequency signal is different from the power supply frequency information stored in the storage means during the cooking operation, the current detection means Is calculated based on the reference current value stored in the storage means, and performs a correction in consideration of a difference in power supply frequency. According to this configuration,
Frequency of commercial AC power supply (50H
z or 60 Hz), the current detection function by the current detection means and the calculation function by the current calculation means can always be operated accurately.

According to a fourth aspect of the present invention, a signal generating means for generating a frequency signal indicating the frequency of a commercial AC power supply is provided, and a current of a known level of a different power supply frequency is stored in the storage means. Is stored in advance as a reference current value in a state corresponding to the power supply frequency information, and the current calculation means stores the current value detected by the current detection means during the cooking operation. The calculation is performed based on the reference current value corresponding to the power supply frequency information indicated by the frequency signal among the reference current values stored in the means. According to such a configuration, similarly to the third aspect of the invention, even when the frequency of the commercial AC power supply is different, the current detection function by the current detection means and the calculation function by the current calculation means are always accurately performed. You can work.

According to a fifth aspect of the present invention, there is provided a temperature detecting means for detecting a temperature of an atmosphere in which the current detecting means is placed, and further comprising a current calculating means for detecting a current detected by the current detecting means during a cooking operation. When the value is calculated based on the reference current value stored in the storage means, the temperature detected by the temperature detection means is also taken into account. According to this configuration, it is possible to prevent a situation in which the detection current value calculated by the current calculation unit after being detected by the current detection unit becomes inaccurate due to a change in the ambient atmosphere temperature.

In order to achieve the second object, an invention according to claim 6 is a heating cooker having a heating means driven by a commercial AC power supply and performing a cooking operation, wherein a current flowing through a predetermined portion is detected. Current detecting means, a voltage detecting means for detecting an input voltage from the commercial AC power supply, a detection value when a current of a known level is detected by the current detecting means, and a known level input voltage by the voltage detecting means. Storage means for storing the detection values at the time of detection as a reference current value and a reference voltage value, respectively; and a current value detected by the current detection means during the cooking operation to a reference current value stored in the storage means. Current calculating means for calculating the input voltage value detected by the voltage detecting means during the cooking operation based on the reference voltage value stored in the storage means. It is obtained by a structure in which a calculation means.

According to this configuration, even if the current value detected by the current detecting means and the input voltage value detected by the voltage detecting means vary during the cooking operation due to a change over time in the circuit constant, etc. The current value and the input voltage value detected by the current detection means and the voltage detection means are:
Since the current is calculated based on the reference current value and the reference voltage value previously stored in the storage means (that is, each detection value when the current and the voltage detection means detect a current and a voltage of a known level, respectively), the current The detection accuracy by the detecting means and the voltage detecting means is improved, and control based on the detected current and the detected voltage can be performed in a stable state.

In this case, as in the invention according to claim 7,
The current detection means, the voltage detection means and the storage means may be arranged on the same substrate or a plurality of substrates which cannot be easily separated. According to this configuration, there is an advantage that the operation of storing the reference current value and the reference voltage value in the storage unit can be performed not in the assembling process of the heating cooker but in, for example, an inspection process at the time of manufacturing a substrate. In addition, the reference current value and the reference voltage value can be easily stored in comparison with the case where the process is performed during the assembling process of the cooking device or at the time of repair and replacement. Further, when a failure occurs in any one or two or more of the current detection means, the voltage detection means, and the storage means, it is only necessary to replace all of them. Work, that is, a cumbersome work that requires a device for generating a predetermined current and voltage is not required, and repair and replacement thereof can be easily performed.

According to the present invention, a signal generating means for generating a frequency signal indicating the frequency of the commercial AC power supply is provided, and the storage means has a reference current value and a reference voltage value, and the reference current value. And power supply frequency information when the reference voltage value is detected is stored in advance, and the power supply frequency indicated by the frequency signal is stored in the storage means during the cooking operation. If the frequency information is different from the frequency information, when calculating the current value and the input voltage value detected by the current detection means and the voltage detection means based on the reference current value and the reference voltage value stored in the storage means, The correction is made in consideration of the difference. According to this configuration, the frequency of the commercial AC power supply (50 Hz or 6
0 Hz), the current detecting function by the current detecting means, the voltage detecting function by the voltage detecting means, and the calculating function by the current calculating means and the voltage calculating means can always be operated accurately.

According to a ninth aspect of the present invention, a signal generating means for generating a frequency signal indicating the frequency of a commercial AC power supply is provided, and the storage means stores currents and input voltages of known levels of different power supply frequencies, respectively. The detection values detected in each case by the current detection means and the voltage detection means are configured to be stored in advance as a reference current value and a reference voltage value in a state corresponding to the power supply frequency information, and the current calculation means and the voltage calculation means are cooked. During operation, the current value and the input voltage value detected by the current detection means and the voltage detection means are set to a reference value corresponding to the power supply frequency information indicated by the frequency signal among the reference current value and the reference voltage value stored in the storage means. It is configured to calculate based on a current value and a reference voltage value. According to such a configuration, similarly to the invention according to claim 8, even when the frequency of the commercial AC power supply is different, the current detection function by the current detection unit, the voltage detection function by the voltage detection unit, and the current The calculation function of the calculation means and the voltage calculation means can always be operated accurately.

According to a tenth aspect of the present invention, in addition to the provision of the temperature detecting means for detecting the temperature of the atmosphere in which the current detecting means and the voltage detecting means are placed, the current calculating means and the voltage calculating means are operated during the cooking operation. In the above, when calculating the current value and the input voltage value detected by the current detection means and the voltage detection means based on the reference current value and the reference voltage value stored in the storage means, the temperature detected by the temperature detection means is also taken into account. It is what it was. According to this configuration, the detected current value calculated by the current calculating unit after being detected by the current detecting unit and the detected voltage value calculated by the voltage calculating unit after being detected by the voltage detecting unit are determined by the ambient atmosphere temperature. Can be prevented from becoming inaccurate due to the change in.

According to the eleventh aspect of the invention, when at least one of the reference current value and the reference voltage value is not stored in the storage means, execution of a cooking operation or operation of a specific load is prohibited. is there. According to this configuration,
If the reference values for the current detection and the voltage detection are not stored due to a component failure or the like, the execution of the cooking operation or the operation of a specific load is prohibited. Can be prevented.

According to a twelfth aspect of the present invention, a predetermined notification operation is performed when at least one of the reference current value and the reference voltage value is not stored in the storage means. According to this configuration, when a value serving as a reference for current detection and voltage detection is not stored due to a component failure or the like, a predetermined notification operation is performed, so that an abnormal cooking operation is performed beforehand. It can be dealt with.

According to a thirteenth aspect of the present invention, based on the current value and the input voltage value calculated by the current calculating means and the voltage calculating means, the input power is controlled to be constant within a range where the entire input current does not exceed the upper limit value. This is a configuration provided with control means. According to this configuration, the total input current is controlled so as not to exceed the upper limit based on the accurate current value and the input voltage value calculated by the current calculation means and the voltage calculation means. The cooking speed can be improved even under restricted conditions.

According to a fourteenth aspect of the present invention, the voltage calculating means is provided with a function of correcting the input voltage value detected by the voltage detecting means according to the on / off state of the heating means and other loads. It is. According to this configuration, for example, even when a load other than the heating means is stopped during the cooking operation and the input voltage fluctuates, the finally obtained detected voltage value can be accurate.

According to a fifteenth aspect of the present invention, the storage means is configured to be nonvolatile so as to retain the stored contents even when the power is shut off. According to this configuration, the reference current value and the reference voltage value stored in the storage means hardly disappear, so that the reliability of the operation of calculating the detected current value or the detected voltage value increases.

According to a sixteenth aspect of the present invention, the current detecting means is configured to detect an input current from a commercial AC power supply or a current flowing to a specific load. According to this configuration, the input current of the entire heating cooker or the input current flowing to each load can be accurately detected.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a microwave oven will be described below with reference to the drawings. First, in FIG. 5 showing a schematic appearance of a microwave oven, a cabinet 1 has a rectangular box shape with an open front surface, and a cooking chamber 2 having a rectangular container shape with an open front surface is formed therein. At the same time, a door 3 for opening and closing the opening of the cooking chamber 2 is rotatably mounted on the front part.

In the cabinet 1, a machine room (not shown) is formed adjacent to the side of the cooking chamber 2, and a magnetron (corresponding to a heating means: FIG.
And a power supply device (shown by reference numeral 29 in FIG. 1) for driving the same. An operation panel 4 is provided at a position on the front side of the machine room in the cabinet 1.
A start switch 5 for starting cooking, an automatic cooking switch 6 corresponding to a plurality of types of cooking menus, a time setting dial 7 for setting a cooking time, and an LED panel 8 for displaying cooking information and time information are provided. Have been.

A heater 9 for oven cooking and grill cooking is provided on the ceiling in the cooking chamber 2. Cooking room 2
A circular rotating plate 10 is provided at the bottom inside.
The rotating plate 10 is obtained by applying an enamel treatment to the surface of a conductive material such as a steel plate, for example, and a configuration in which a circular cooking dish (not shown) is placed on the rotating plate 10 at the time of range cooking. It has become. The cooking dish is made of a microwave transmitting material such as glass or ceramic.

FIG. 1 schematically shows an electric configuration of the microwave oven, which will be described below. In FIG. 1, a predetermined frequency (50 Hz or 6 Hz) is supplied between a pair of power supply lines 11 and 12 from a commercial AC power supply 13 through a fuse 14, a noise filter 15 and a thermal switch 16.
0 Hz). The primary winding 17a of the step-down transformer 17 is connected between the two power lines 11 and 12, and a series circuit of the fan motor 18 and the relay switch 19 is connected. still,
The fan motor 18 is disposed in the machine room (not shown), and a blower fan (not shown) for cooling electric components in the machine room is driven in the driven state. I have.

One power supply line 11 is connected to a power supply line 11a via door switches 20 and 21 which are turned on when the door 3 is closed, and the other power supply line 12 is connected to a power supply line via a main relay switch 22. 12a.
A door switch 23 functioning as a short-circuit switch is connected between the common connection point of the door switches 20 and 21 and the power supply line 12. The door switch 23 is turned on when the door 3 is opened. It has become.

Between the power supply lines 11a and 12a, a lamp 24 for illuminating the inside of the cooking chamber 2, a series circuit of a relay switch 25 and a motor 26 for driving the rotary plate 10, a relay switch 27 and a heater Each series circuit is connected.

A power supply unit 29 connected between the power supply lines 11a and 12a via a relay switch 28 is for supplying resonance power to the magnetron 30. Although not specifically shown, a rectifying / smoothing circuit and an inverter are provided. It has a well-known configuration including a circuit, a step-up transformer, a high-voltage capacitor, a high-voltage diode, and the like.

The power supply line 12 is provided with a current transformer 31, and a secondary output of the current transformer 31 is supplied to a current detection circuit 32 (corresponding to current detection means). The secondary winding 17b of the step-down transformer 17 has a constant voltage power supply circuit 33, a voltage detection circuit 34 (corresponding to voltage detection means), a frequency signal generation circuit 3
5 (corresponding to signal generation means) is connected. These current transformer 31, current detection circuit 32, constant voltage power supply circuit 33, voltage detection circuit 34, frequency signal generation circuit 35
Are arranged on the same substrate together with a nonvolatile memory 38 (corresponding to storage means) to be described later, or on a plurality of substrates which are connected (connected) by solder or the like and cannot be easily separated.

The current detection circuit 32, the constant voltage power supply circuit 33, the voltage detection circuit 34, and the frequency signal generation circuit 35 are specifically configured as shown in FIG. That is, the current detection circuit 32 is a rectifier circuit 3 for performing full-wave rectification on the secondary-side output of the current transformer 31.
1a, a series circuit (integrating circuit) of a charging resistor 31b and a capacitor 31c connected to the output terminal of the rectifier circuit 31a, and a discharging resistor 31d connected in parallel with the series circuit. ing. Therefore, in the current detection circuit 32, a current detection signal Iin of a voltage level corresponding to the input current value from the commercial AC power supply 13 appears at both ends of the capacitor 31c.
in is the control unit 36 (current calculation means, voltage calculation means,
(Corresponding to control means).

The constant voltage power supply circuit 33 includes a center tap type rectifier circuit 33a for full-wave rectifying an alternating current supplied through the secondary winding 17b, a capacitor 33b for smoothing the rectified output, and a constant voltage receiving the smoothed output. Voltage circuit 33
c and a capacitor 33 for stabilizing the constant voltage output.
d, the output of which is supplied to the control unit 36 as a control power supply and to other circuit elements through a power supply terminal + Vcc.

The voltage detection circuit 34 includes diodes 34a and 34b having cathodes connected to both ends of the secondary winding 17b.
A resistor 34c connected between the anodes of the diodes 34a and 34b and the power supply terminal + Vcc; a series circuit of resistors 34d and 34e having a relatively large resistance connected in parallel with the resistor 34c; And a capacitor 34f connected in parallel. In the voltage detection circuit 34 thus configured, a voltage detection signal Vin having a voltage level corresponding to the input voltage value from the commercial AC power supply 13 appears at a common connection point between the resistors 34d and 34e. The signal Vin is provided to the control unit 36.

The frequency signal generating circuit 35 has an emitter connected to the power supply terminal + Vcc and a collector connected to the resistor 35a.
, A pnp-type transistor 35b connected to the ground terminal, a resistor 35c connected to the base of the transistor 35b and one end of the secondary winding 17b, and a bias resistor between the emitter and the base of the transistor. 35d. In the frequency signal generating circuit 35 configured as described above, a pulse-like frequency signal Ps having a cycle corresponding to the frequency of the commercial AC power supply 13 is generated from the collector of the transistor 35b. 13 is given to the control unit 36 as a signal indicating the frequency.

Returning to FIG. 1, the temperature detecting circuit 37 (corresponding to temperature detecting means) is, for example, a thermistor arranged to detect the temperature of the atmosphere in which the current detecting circuit 32 and the voltage detecting means 34 are placed. The control unit 36 is provided with a temperature detection signal Vt having a voltage level corresponding to the detected temperature. The non-volatile memory 38 stores a reference current value and a reference voltage value, which will be described later, in association with the power supply frequency information at a stage before the product is shipped. It is configured to be able to exchange.

The control unit 36 includes, in addition to the above-described current detection signal Iin, voltage detection signal Vin, pulse signal Ps, and temperature detection signal Vt, the start switch 5, automatic cooking switch 6, time setting dial 7, and the like. Operation means 3
9 is input.

The control unit 36 controls the ON / OFF of the main relay switch 22, the relay switches 19, 25, 27, 28 based on the input signal, the data stored in the nonvolatile memory 38, and a preset program. The display / notification unit 40 including the LED panel 8 and an electronic buzzer (not shown) is controlled, and the operation of an inverter circuit (not shown) in the power supply device 29 is controlled. The relay switches 19, 22, 25, 2
On / off control of the relay coils 7 and 28
This is performed by controlling the power cutoff of a, 22a, 25a, 27a, 28a through the relay drive circuit 41.

The control unit 36 is indicated by the input current value indicated by the current detection signal Iin from the current detection circuit 32 and the voltage detection signal Vin from the voltage detection circuit 34, particularly during range cooking by the magnetron 30. Control for increasing or decreasing the output of the magnetron 30 through an inverter circuit (not shown) based on the input voltage value is performed as described later. In this case, the control unit 36 outputs the current detection signal I from the current detection circuit 32.
The input current value indicated by “in” and the input voltage value indicated by the voltage detection signal Vin from the voltage detection circuit 34 are stored in the storage data of the nonvolatile memory 38 and the frequency signal generation circuit 35.
The calculation is performed based on the correction based on the frequency signal Ps from the temperature detection circuit 37 and the temperature detection signal Vt from the temperature detection circuit 37. Hereinafter, a configuration related to the calculation operation will be described.

As described above, the non-volatile memory 38 stores the reference current value and the reference voltage value in a state in which the reference current value and the reference voltage value are associated with the power supply frequency information before the product is shipped.
In this case, the operation of storing the reference current value is performed as follows. First, an AC current of a known level is applied to the primary side of the current transformer 31 in a board assembled state in which at least the current transformer 31, the current detection circuit 32, and the nonvolatile memory 38 are mounted on the board. Specifically, for example, 98.5V
A current of 14.3 A flows through a resistive load in a state where an AC voltage of / 60 Hz is applied. At this time, the current value detected by the current detection circuit 32 (indicated by the voltage level of the current detection signal Iin) is determined. Is stored in the nonvolatile memory 38 as a quantized reference current value. At the same time, power supply frequency information indicating that the power supply frequency is 60 Hz is stored in association with the reference current value.

The operation of storing the reference voltage value is performed as follows. First, at least the step-down transformer 17, the constant voltage power supply circuit 33, the voltage detection circuit 34, the frequency signal generation circuit 35
In addition, in a board assembled state in which the nonvolatile memory 38 is incorporated in the board, a known level AC voltage is applied to the primary side of the step-down transformer 17 and a predetermined load is operated. Specifically, for example, an AC voltage of 98.5 V / 60 Hz is applied,
In this state, the relay switches 19, 22, 25, and 28 (loads that are simultaneously operated when the magnetron 30 operates) are operated. At this time, the voltage value (the voltage detection signal) detected by the voltage detection circuit 34 is detected. (Indicated by the voltage level of Vin) is stored in the nonvolatile memory 38 as a quantized reference voltage value. At the same time, power supply frequency information indicating that the power supply frequency is 60 Hz is stored in association with the reference voltage value. The reason why the relay switches 19, 22, 25, and 28 are operated as described above is that, during range cooking, the load current of the step-down transformer 17 increases as these loads operate, and the output voltage of the step-down transformer 17 increases. This is in order to cope with the phenomenon of decrease.

Thus, during the range cooking operation, the control unit 36 controls whether the input current detected through the current detection circuit 32 has a margin,
When the input voltage (power supply voltage) detected through the inverter is lowered, the control to increase the output of the magnetron 30 to a predetermined level through the inverter circuit is performed based on the detected input current and the detected input voltage. However, the output (and, consequently, the cooking speed) of the magnetron 30 is maximized within a range not exceeding 15 A (corresponding to the outlet capacity and breaker capacity of the household wiring).

In this case, according to the present embodiment, the control unit 36 outputs the current value indicated by the current detection signal Iin from the current detection circuit 32 to the reference current value (current detection circuit 32 And the input voltage value indicated by the voltage detection signal Vin from the voltage detection circuit 34 is calculated based on a current value when a current of a known level is detected. The control for calculating based on the voltage at the time when the voltage of the known level is detected by the detection circuit 34 is performed. For this reason, even when the input current value detected by the current detection circuit 32 and the input voltage value detected by the voltage detection circuit 34 vary due to a change over time of the circuit constant or the like, the above-described calculation control can be used. , The detection accuracy of the current detection circuit 32 and the voltage detection circuit 34 is increased, and control based on the detected current and the detected voltage, that is, the range in which the entire input current does not exceed the upper limit of 15 A (for example, , 14.6A
(In the range of ± 0.2 A), the control for maximizing the output of the magnetron 30 can be performed in a stable state.
In short, the improvement of the cooking speed can be realized even under the condition where the entire input current is restricted.

By the way, in the current transformer 31 required for outputting the current detection signal Iin, the relationship between the input current on the primary side and the output voltage on the secondary side is, as shown in FIG. There is a situation that the state is changed according to the difference. Further, even in the step-down transformer 17 necessary for output of the voltage detection signal Vin, the relationship between the input voltage on the primary side and the output voltage on the secondary side is changed according to the difference in the power supply frequency as described above. There will be circumstances.

In order to deal with such a situation, the control unit 36 determines whether the power supply frequency is 50 Hz or 60 Hz based on the frequency signal Ps from the frequency signal generation circuit 35, and determines whether the power supply frequency is non-volatile. Power supply frequency information stored in the functional memory 38 (in this embodiment, “6
0 Hz "), the input current value indicated by the current detection signal Iin and the voltage detection signal V
The input voltage value indicated by “in” is stored in the nonvolatile memory 38.
When the calculation is performed based on the reference current value and the reference voltage value stored in the memory, the correction taking into account the power supply frequency difference (FIG.
The relationship between the primary side input current and the secondary side output voltage in the current transformer 31 as shown in FIG.
7 is performed in consideration of the relationship between the primary-side input voltage and the secondary-side output voltage.

As a result, even if the frequency (50 Hz or 60 Hz) of the commercial AC power supply 13 serving as the power supply for the microwave oven is different, the current detection function by the current detection circuit 32, the voltage detection function by the voltage detection circuit 34, and The calculation function of the detection current and the detection voltage by the control unit 36 can always be operated accurately.

On the other hand, in the current transformer 31,
As shown in FIG. 4, there is a situation that the output fluctuates according to the level of the ambient temperature. In order to deal with such a situation, the control unit 36, based on the temperature detection signal Vt from the temperature detection circuit 37, controls the input current value indicated by the current detection signal Iin and the input voltage indicated by the voltage detection signal Vin. When the value is calculated based on the reference current value and the reference voltage value stored in the non-volatile memory 38, correction taking into account the temperature indicated by the temperature detection signal Vt (the output of the current transformer 31 as shown in FIG. Correction taking into account the temperature characteristics of the above).
As a result, the detected current value obtained by calculating the current value indicated by the current detection signal Iin from the current detection circuit 32 based on the reference current value stored in the non-volatile memory 38 corresponds to a change in the ambient atmosphere temperature. Inaccuracies due to this can be prevented beforehand, and the output control of the magnetron 30 as described above can be performed in a more stable state.

In this embodiment, the current detection circuit 3
2. Since the voltage detection circuit 34 and the nonvolatile memory 38 are arranged on the same substrate or a plurality of substrates that cannot be easily separated, the reference current value and the reference voltage value are stored in the nonvolatile memory 38, respectively. There is an advantage that the operation to be performed can be performed not in the assembling process of the microwave oven but in, for example, an inspection process in manufacturing a substrate. As a result, the reference current value and the reference voltage value can be stored more easily than when the process is performed during the assembling process of the microwave oven or at the time of repair and replacement. In addition, any one or two of the current detection circuit 32, the voltage detection circuit 34, and the nonvolatile memory 38
In the event of a failure caused by the above means, it is only necessary to replace the entirety of them, so at the time of repair and replacement, an operation for storing the reference current value and the reference voltage value, that is, a device for generating predetermined current and voltage, The troublesome work that needs to be prepared becomes unnecessary, and the repair and replacement can be easily performed.

The reference current value and the reference voltage value are
Non-volatile memory 3 that retains stored contents even when power is off
8, the reference current value and the reference voltage value once stored are hardly lost, and as a result, the current value detected by the current detection circuit 32 or the voltage value detected by the voltage detection means 34 Is more reliable.

The present invention is not limited to the above-described embodiment, but can be modified or expanded as follows. When the control unit 36 does not store at least one of the reference current value and the reference voltage value in the non-volatile memory 38, the control unit 36 controls the execution of the range cooking operation or the operation of a specific load (for example, the magnetron 30). Functions may be added. According to such a configuration,
If the reference values for the current detection and the voltage detection are not stored due to defective parts, etc., execution of the range cooking operation or operation of a specific load is prohibited. There is an advantage that can be prevented beforehand.

When the control unit 36 does not store at least one of the reference current value and the reference voltage value in the nonvolatile memory 38, for example, the LED panel 8
A control function of performing a predetermined notification operation may be added through the. According to such a configuration, when a value serving as a reference for current detection and voltage detection is not stored due to a component failure or the like, a predetermined notification operation is performed, so that an abnormal cooking operation is performed. It can be dealt with beforehand.

The control unit 36 may be provided with a function of correcting the input voltage value detected by the voltage detection circuit 34 according to the on / off state of the magnetron 30 and other loads (such as the motor 26). According to this configuration, for example, even when the load other than the magnetron 30 is stopped during the cooking operation and the input voltage fluctuates, the finally obtained detected voltage value can be made accurate.

In the above embodiment, the reference current value and the reference voltage value obtained based on the current and the voltage of the known level having the frequency of 60 Hz are stored in the nonvolatile memory 38 by the power supply frequency indicating that the power supply frequency is 60 Hz. Although the configuration is such that the information is stored together with the information, in addition to this, the detected value in each case where the current and the voltage of the power supply frequency of 50 Hz are detected by the current detection circuit 32 and the voltage detection circuit 34, respectively, is
The configuration may be such that the reference current value and the reference voltage value in a state corresponding to the power supply frequency information indicating that the power supply frequency is 50 Hz are stored. In this case, the control unit 36
Represents the current value and the voltage value detected by the current detection circuit 32 and the voltage detection circuit 34 as the frequency signal generation circuit 3 out of the reference current value and the reference voltage value stored in the nonvolatile memory 38.
5 is corrected based on the reference current value and the reference voltage value corresponding to the power supply frequency information indicated by the frequency signal Ps.

Although the input current of the entire microwave oven is detected by the current detection circuit 32, the current detection circuit 32 may be configured to detect a current flowing through a specific load (for example, the magnetron 30). In order to control the output of the magnetron 30, both the current detection signal Iin from the current detection circuit 32 and the voltage detection signal Vin from the voltage detection circuit 34 are used, but at least control using the current detection signal Iin is performed. The voltage detection circuit 34 may be provided as needed. Further, the frequency signal generating circuit 35
And the temperature detection circuit 37 may be provided as needed.

The work of storing the reference current value and the reference voltage value is as follows.
Although the configuration is performed at the stage of board assembly, it may be performed at the stage when the product is finally completed. However, in this case, it is necessary to apply a power supply voltage in consideration of a voltage drop in a path from a power outlet of the product to the primary side of the step-down transformer 17.

In the above embodiment, the present invention is applied to a microwave oven having a heater cooking function. However, the present invention is not limited to this.
In the above embodiment, the magnetron 3 was used as the heating means.
Although 0 is exemplified, the heater 9 may be used, or another heating means such as an induction heating coil or a halogen lamp heater may be used.

[0056]

As is clear from the above description, in the cooking device of the present invention, the current value detected by the current detecting means during the cooking operation is determined by detecting the current of a known level by the current detecting means. , The detection accuracy of the current detecting means can be improved, and control based on the detected current can be performed in a stable state. In addition to the above-described calculation function of the detection current, a voltage value detected by the voltage detection means during the cooking operation is calculated based on a detection value when a voltage of a known level is detected by the voltage detection means. With the configuration, in addition to the detection accuracy of the current detection means, the detection accuracy of the input voltage from the commercial AC power supply can be improved,
The control based on the detected current and the detected voltage can be performed in a stable state.

[Brief description of the drawings]

FIG. 1 is an electrical configuration diagram showing one embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a main part.

FIG. 3 is a characteristic diagram showing a relationship between a primary input current and a secondary output voltage of a current transformer.

FIG. 4 is a temperature characteristic diagram of an output of a current transformer.

FIG. 5 is a perspective view showing the entire configuration.

[Explanation of symbols]

9 is a heater, 13 is a commercial AC power supply, 17 is a step-down transformer, 26 is a motor, 29 is a power supply device, 30 is a magnetron (heating means), 31 is a current transformer, 32 is a current detection circuit (current detection means), and 33 is Constant voltage power supply circuit, 3
4 is a voltage detection circuit (voltage detection means), 35 is a frequency signal generation circuit (signal generation means), 36 is a control unit (current calculation means, voltage calculation means, control means), and 37 is a temperature detection circuit (temperature detection means) , 38 indicate a non-volatile memory (storage means).

Claims (16)

[Claims] 1. A heating cooker provided with a heating means driven by a commercial AC power supply for performing a cooking operation, a current detection means for detecting a current flowing to a predetermined portion, and a current of a known level detected by the current detection means. Storage means for storing a detection value at the time of performing as a reference current value in advance, and a current calculation for calculating a current value detected by the current detection means during a cooking operation based on the reference current value stored in the storage means. And a cooking device. 2. The cooking device according to claim 1, wherein the current detection means and the storage means are arranged on the same substrate or a plurality of substrates which cannot be easily separated. 3. A signal generating means for generating a frequency signal indicating a frequency of a commercial AC power supply, wherein the storage means stores in advance a reference current value and power supply frequency information when the reference current value is detected. The current calculation means is configured to store the current value detected by the current detection means when the power supply frequency indicated by the frequency signal is different from the power supply frequency information stored in the storage means during the cooking operation. The heating cooker according to claim 1, wherein when performing calculation based on the reference current value stored in the storage unit, correction is performed in consideration of a difference in power supply frequency. 4. A signal generating means for generating a frequency signal indicating the frequency of a commercial AC power supply is provided, and the storage means has a known level of current of a different power supply frequency detected by the current detecting means. The current value is configured to be stored in advance as a reference current value in a state corresponding to the power supply frequency information, and the current calculation unit is configured to store the current value detected by the current detection unit during the cooking operation in the storage unit. The cooking device according to claim 1, wherein the current value is calculated based on a reference current value corresponding to power supply frequency information indicated by the frequency signal. 5. A temperature detecting means for detecting a temperature of an atmosphere in which the current detecting means is placed, wherein the current calculating means stores a current value detected by the current detecting means during a cooking operation in a storage means. The heating cooker according to any one of claims 1 to 4, wherein when calculating based on the current value, a temperature detected by the temperature detecting means is also taken into account. 6. A heating cooker provided with a heating means driven by a commercial AC power supply and performing a cooking operation, wherein a current detection means for detecting a current flowing to a predetermined portion, and an input voltage from the commercial AC power supply is detected. Voltage detection means, and a detection value when a current of a known level is detected by the current detection means and a detection value when an input voltage of a known level is detected by the voltage detection means are defined as a reference current value and a reference voltage value, respectively. Storage means for storing; current calculation means for calculating a current value detected by the current detection means during the cooking operation based on a reference current value stored in the storage means; and voltage detection means during the cooking operation A voltage calculating means for calculating an input voltage value detected by the storage means based on the reference voltage value stored in the storage means. 7. The cooking device according to claim 6, wherein the current detection means, the voltage detection means and the storage means are arranged on the same substrate or a plurality of substrates which cannot be easily separated. 8. A signal generating means for generating a frequency signal indicating the frequency of a commercial AC power supply is provided, and the storage means detects a reference current value and a reference voltage value and the reference current value and the reference voltage value. The power supply frequency information when the power supply frequency indicated by the frequency signal is different from the power supply frequency information stored in the storage means during the cooking operation. When calculating the current value and the input voltage value detected by the current detection means and the voltage detection means based on the reference current value and the reference voltage value stored in the storage means, the correction taking into account the difference in the power supply frequency is performed. The cooking device according to claim 6 or 7, wherein the heating is performed. 9. A storage device comprising: a signal generating means for generating a frequency signal indicating a frequency of a commercial AC power supply; Means for detecting in each case the reference value and the reference voltage value in a state corresponding to the power supply frequency information. The current calculation means and the voltage calculation means detect the current during the cooking operation. A current value and an input voltage value detected by the voltage detection means and a reference current value and a reference voltage value corresponding to the power supply frequency information indicated by the frequency signal among the reference current value and the reference voltage value stored in the storage means; The heating cooker according to claim 6, wherein the calculation is performed based on: 10. A temperature detecting means for detecting a temperature of an atmosphere in which the current detecting means and the voltage detecting means are placed, wherein the current calculating means and the voltage calculating means are arranged such that the current detecting means and the voltage detecting means during the cooking operation. 10. The temperature detected by the temperature detecting means when calculating the current value and the input voltage value to be detected based on the reference current value and the reference voltage value stored in the storage means.
A cooking device according to any one of the above. 11. The method according to claim 6, wherein execution of a cooking operation or operation of a specific load is prohibited when at least one of the reference current value and the reference voltage value is not stored in the storage means. The heating cooker according to any one of the above. 12. The cooking according to claim 6, wherein a predetermined notification operation is performed when at least one of the reference current value and the reference voltage value is not stored in the storage unit. vessel. 13. A control means for controlling the input power to be constant within a range where the entire input current does not exceed the upper limit value, based on the current value and the input voltage value calculated by the current calculation means and the voltage calculation means. The cooking device according to any one of claims 1 to 12, characterized in that: 14. The voltage calculating means is provided with a function of correcting an input voltage value detected by the voltage detecting means in accordance with the on / off state of the heating means and other loads. 13. The cooking device according to any one of 13 to 13 above. 15. The cooking device according to claim 1, wherein the storage unit is configured to be non-volatile so as to retain the stored contents even when the power is shut off. 16. The cooking device according to claim 1, wherein the current detection means detects an input current from a commercial AC power supply or a current flowing to a specific load.