JP2007147095A - Heating cooking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating cooking device comprising a safety device for preventing an electric leak and electric shock, and reducing power consumption during a wait mode. <P>SOLUTION: An operation is started by starting a power supply based on a signal from a start signal generating portion 19 during a wait mode not performing power supply by a power supply portion 17, by a microcomputer 13 and an electric leak determining portion 16, and the power supply by the power supply portion 17 is stopped when the electric leak is detected by the electric leak determining portion 16, thus risks of electric leak and electric shock can be reduced, and the power consumption in the wait mode can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cooking device that reduces power consumption during standby, and more particularly to a safety device that prevents electric leakage or electric shock of a cooking device that uses water or generates steam.

  2. Description of the Related Art Conventionally, in a microwave oven as this type of cooking device, a ground terminal is provided on the main body, and this is used while being grounded to prevent a user from being in danger of electric shock. In addition, there is a case where an earth leakage blocking function is mounted assuming that the ground terminal provided in the microwave oven body is not securely grounded (see Patent Document 1).

FIG. 5 shows a circuit diagram of a conventional microwave oven described in Patent Document 1. In FIG. As shown in FIG. 5, a magnetron 104 that oscillates in a power supply circuit composed of a high-voltage transformer 101, a capacitor 102, and a diode 103, a control board 106 that operates by supplying power from a low-voltage transformer 105, A relay 107 that opens and closes the connection, and a zero-phase current transformer 108 attached to a power line between the power source and the relay 107. The relay 107 is operated by a control signal from the control board 106, and the high-voltage transformer 101 When the power is supplied to the magnetron 104, the magnetron 104 oscillates to heat the food. In addition, the control board 106 detects the leakage current by monitoring the unbalanced current detected by the zero-phase current transformer 108. When the leakage is detected, the relay 107 is immediately opened to interrupt the leakage current. I have to.
JP 58-175282 A

  However, recently, it has become a general requirement to reduce the standby power of the cooking device to 1 W or less, and for a microwave oven that does not have a clock function, it is required to reduce the standby power to 50 mW or less. Efforts are being made to bring standby power as close to zero as possible. In the conventional configuration, power is always supplied to the control means that is the control board, and the power consumed by the microcomputer constituting the control means and its peripheral circuits cannot be ignored. Furthermore, since a circuit for detecting electric leakage is also operating, there is a problem that it is difficult to suppress standby power to 50 mW or less.

  This invention solves the said conventional subject, and it aims at providing the cooking device which provided the safety device which prevents an electric leakage or an electric shock, and reduced the power consumption at the time of standby.

  In order to solve the conventional problems, a heating cooker according to the present invention includes a load, a control unit that controls the load, a power source unit of the control unit, and supply of power from the power source unit to the control unit. A power supply unit that performs a signal, a start signal generation unit that gives a signal to the power supply unit to start supply of power, an electric circuit that supplies commercial power to the load and the power supply unit, and an unbalanced current that flows through the electric circuit A current detection unit for detecting and a leakage determination unit for determining the presence or absence of leakage based on a signal from the current detection unit, the control means and the leakage determination unit are in a standby state in which the power supply unit is not supplying power The power supply is started by the signal of the start signal generator during the operation, and the operation starts.If the signal of the leakage determination unit is normal, the power supply of the power supply unit is continued to continue the subsequent operation. And the power It is obtained as a standby state by stopping the supply of power supply unit.

  Thereby, in the standby state, since the supply of power to the control unit and the leakage determination unit is turned off, power consumption in the control unit and the leakage determination unit can be eliminated.

  Moreover, the control means of the heating cooker of the present invention includes a power switch having a reset function for opening and closing an electric path to the load and the power supply unit, and opens the power switch when the signal of the leakage determination unit is not normal. It is a thing.

  As a result, even if a leakage occurs in the power supply unit or the control means, it is possible to prevent an electric shock by turning off the switch by turning off the switch.

  The heating cooker of the present invention includes a safety device that prevents electric leakage or electric shock, and can reduce power consumption during standby.

  According to a first aspect of the present invention, a load, a control unit that controls the load, a power supply unit of the control unit, a power supply unit that supplies power from the power supply unit to the control unit, and the power supply unit An activation signal generating unit that gives a signal and starts supplying power, an electric circuit that supplies commercial power to the load and the power supply unit, a current detection unit that detects an unbalanced current flowing in the electric circuit, and the current detection unit A leakage determining unit that determines the presence or absence of leakage based on a signal of the power supply, and the control means and the leakage determining unit are powered by a signal of the activation signal generating unit during a standby state in which the power supply unit is not supplying power. Is started, and if the signal of the leakage determination unit is normal, the power supply of the power supply unit is continued and the subsequent operation is continued, and there is no occurrence of leakage and the operation is performed for a predetermined time. If there is no transition Wherein by stopping the power supply of the power supply unit, so out to eliminate the power consumption of the control means and the leakage determination unit it is possible to reduce the power consumption during standby.

  According to a second aspect of the invention, in particular, the activation signal generator of the first aspect of the invention includes a door switch that operates in conjunction with opening and closing of the door, and generates a signal by opening or closing the door switch. By opening and closing the door, which is always performed when cooking an object, the power is turned on without a power switch, so that the usability is not impaired.

  In a third aspect of the invention, in particular, in the first aspect of the invention, a switch for opening and closing the connection between the load and the electric circuit is provided, and the control means is configured to open the switch when the signal of the leakage determination unit is not normal. As a result, even if a leakage occurs due to a load, an electric shock can be prevented by turning off the switch.

  According to a fourth aspect of the invention, in particular, in the first aspect of the invention, the power switch having a reset function for opening and closing the load and the power path to the power source unit is provided, and the control means is configured to operate the power source when the signal of the leakage determination unit is not normal. By adopting a configuration in which the switch is opened, even if a leakage occurs in the power supply unit or the control means, an electric shock can be prevented by turning off the switch by turning off the switch.

  The fifth invention particularly includes a power switch having a reset function for opening and closing an electric circuit to the load and the power supply unit and a switch for opening and closing a connection between the load and the electric circuit in the first invention, If the signal of the part is not normal, the switch is opened, and then the power switch is opened when the signal of the leakage determination part is not normal. It is possible to estimate whether there is a leakage in the control means.

In a sixth aspect of the present invention, in particular, in any one of the third to fifth aspects of the present invention, a notification unit is provided, and the control unit is configured to notify the occurrence of a leakage when the signal of the leakage determination unit is not normal. Therefore, for example, by displaying an error display, it is possible to notify the occurrence of a leakage.

  In the seventh aspect of the invention, in particular, the control means of the sixth aspect of the invention is configured so as not to stop the power supply of the power supply unit while notifying the occurrence of leakage, and is not in a standby state. The notification is continued.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is an external view of a heating cooker according to the first embodiment of the present invention. In FIG. 1, a door 2 is provided on the front surface of a main body 1 so as to be freely opened and closed. An operation panel 3 is provided with a display element 4 and a keyboard 5. A ground wire 7 is connected to a ground terminal 6 provided on the main body 1 to ground the main body 1. Reference numeral 8 denotes a power cable.

  FIG. 2 shows a circuit diagram of the cooking device according to the first embodiment of the present invention. In FIG. 2, 10a and 10b indicate the load of the present invention with a high-frequency generator and a heater as a heating source, each composed of a magnetron or the like that generates microwaves for heating food to be heated. . The power for these loads is supplied from a commercial power line 8a drawn from the power cable 8 through relays 11a, 11b, 11c, and 11d as switches that are controlled by the control means of the present invention. In addition, all loads are cut off from the power supply by relays 11a and 11b. The relays 11a, 11b, 11c, and 11d are operated by turning on the transistors 12a, 12b, 12c, and 12d so that a current flows through the relay coil. These transistors operate based on a control signal from the microcomputer 13 constituting the control means.

  Reference numeral 14 denotes an AC / DC converter that constitutes a power supply unit that generates a DC voltage (+5 V) necessary for the operation of the control means. The AC / DC converter 14 is directly connected to a commercial power circuit 8 a supplied from the power cable 8. This type of power supply has a function of suppressing power consumption to 10 mW or less in a state where the output of the power supply is not taken at all. By reducing unnecessary power consumption during standby by using such an AC / DC converter 14, the standby power consumption of the cooking device can be reduced by taking advantage of the power saving characteristics of the AC / DC converter itself during standby. . The electric circuit 8a drawn from the power cable 8 is provided with a zero-phase current transformer 15 which is a current detection unit of the first embodiment of the present invention, thereby detecting the occurrence of an unbalanced current in the electric circuit 8a. The unbalanced current is such that the current supplied from the electric circuit after the zero-phase current transformer 15 is connected to the outline and the outline of the main body 1 due to insulation deterioration or ground fault of the electric circuit and the load connected to the electric circuit and the control means. This is caused by leakage from the ground.

  Reference numeral 16 denotes a leakage determination unit that converts the output of the zero-phase current transformer 15 into a signal level that can be determined by the microcomputer 13. For example, when the unbalanced current exceeds 10 mA, the leakage determination unit 16 outputs an output voltage of the Vdd level that is the power supply voltage of the microcomputer 13. In the case of 10 mA or less, an output voltage of 0 V which is the reference potential of the microcomputer 13 is output. Based on the output signal of the leakage determination unit 16, the microcomputer 13 determines the presence or absence of leakage. The current value of the unbalanced current is set to a value that does not affect the human body in consideration of conditions such as the operation time from when the leakage is detected until the contacts of the relays 11a and 11b are opened. is there.

Reference numeral 17 denotes a power supply unit according to the present invention, which can control power supply to the control means and the like by turning on and off the transistor 18 constituting the power supply unit 17. In the first embodiment of the present invention, the microcomputer 13, the leakage determination unit 16, the display element 4, and the keyboard 5 constituting the control unit are operated by supplying power from the power supply unit.

  Reference numeral 19 denotes an activation signal generator, which is provided with a door switch 20 that is turned on / off in conjunction with the opening / closing operation of the door 2 provided on the front surface of the main body 1. The activation signal generator 19 generates an activation signal by the on / off operation of the door switch 20. The power supply unit 17 is continuously turned on or on by a start signal output from the start signal generator 19 or a power holding signal output from the microcomputer 13. In the state where the transistor 18 of the power supply unit 17 is turned off, the power supply to the control means or the like is stopped, and the microcomputer 13 that controls the entire heating cooker is in the stopped state. . Furthermore, since the relays 11a, 11b, 11c, and 11d connected to the output of the AC / DC converter 14 are turned off, the transistors 12a, 12b, 12c, and 12d connected to the coil side of each relay are turned off. Power is no longer consumed. Further, in the activation signal generation unit 19, since the door switch 20 is turned off when the door 2 is closed, power is not consumed from + 5V. In this way, the output current of the AC / DC converter 14 is minimized, and the power consumption of the cooking device is also minimized.

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

  First, the operation of the activation signal generator 19 will be described. FIG. 3 is a timing chart showing the voltage of each part of the activation signal generator 19 in the opening / closing operation of the door 2, and FIG. 3A is a timing chart when the door 2 is closed and the door switch 20 is OFF. b) is a timing chart when the door 2 is closed and the door switch 20 is on. FIG. 3A shows a period from when the door is closed in the standby state until the door is opened and the microcomputer 13 operates to continue the operation state. Regarding the relationship between the door 2 and the door switch 20, the door switch 20 is turned off when the door 2 is closed, and the door switch 20 is turned on when the door 2 is opened. When the user opens the door 2 from the standby state, the door switch 20 is turned on and +5 V is generated in V1 and V2. When a voltage is generated in V2, a charging current flows through the capacitor 21, and a voltage V3 in FIG. 3A is generated until the charging current becomes 0 in V3. Due to the voltage generated at V3, the transistor 22 is turned on, V4 becomes 0V level, the base current of the transistor 18 flows, and the transistor 18 is turned on. In this way, the power supply unit 17 is turned on by the operation of the activation signal generation unit 19 and the microcomputer 13 starts to operate. Then, the microcomputer 13 outputs a power holding signal (V5), the transistor 23 of the power supply unit 17 is turned on, and + 5V is continuously supplied to Vdd, and the operation is continued.

  FIG. 3B shows the case where the on / off logic of the door switch 20 is reversed. The relationship between the door 2 and the door switch 20 is that when the door 2 is closed, the door switch 20 is turned on and the door 2 is turned on. When open, the door switch 20 is off. When the user opens the door 2 from the standby state, the door switch 20 is turned off and V1 changes from + 5V to 0V. V2 gradually decreases from + 5V to 0V as the electric charge stored in the capacitor 21 is discharged through the resistor 24, and maintains 0V until the door is closed again.

Next, when the door 2 is closed and the door switch 20 is turned on, V2 becomes + 5V, and when a voltage is generated at V2, a charging current flows through the capacitor 21 until the charging current becomes 0 at V3 as shown in FIG. Voltage is generated. Due to the voltage generated at V3, the transistor 22 is turned on, V4 becomes 0V level, the base current of the transistor 17 flows, and the transistor 18 is turned on. In this way, the power supply unit 17 is turned on by the operation of the activation signal generation unit 19 and the microcomputer 13 starts to operate. Then, the microcomputer 13 outputs a power holding signal (V5), the transistor 23 of the power supply unit 17 is turned on, and + 5V is continuously supplied to Vdd, and the operation is continued.

  Next, when the power supply unit 17 is turned on and +5 V is supplied to Vdd, the leakage determination unit 16 operates. The zero-phase current transformer 15 can detect an unbalanced current generated in the electric circuit 8a, and an output voltage proportional to the unbalanced current is generated. The leakage determination unit 16 determines the leakage when the output voltage generated in the zero-phase current transformer 15 exceeds the detection voltage, and outputs a determination result to the microcomputer 13. In a normal state where no electric leakage occurs, the microcomputer 13 turns on and off the relays 11a, 11b, 11c, and 11d in a pre-programmed sequence, controls the high-frequency generator and the heating source, and cooks the food. To do. When the state does not change for a predetermined time after cooking is finished (for example, when the keyboard 5 is not operated), the microcomputer 13 drops the power holding signal to 0 V level and turns off the power supply unit 17. As a result, the power supply to the control means and the leakage determination unit 16 is stopped, and a standby state is set.

  Next, the operation when the occurrence of electric leakage is detected will be described. When the relays 11a, 11b, 11c, and 11d are turned on / off and a voltage is applied to the load that is the high-frequency generator and the heating source, the microcomputer 13 immediately turns off the relay and stops the voltage application. Furthermore, a display for notifying the occurrence of electric leakage is displayed on the display element 4 to notify the user of the occurrence of electric leakage and to urge the user to stop using the cooking device. In addition, while notifying the occurrence of electric leakage, the notification is continued without entering the standby state.

(Embodiment 2)
FIG. 4 is a circuit diagram of a microwave oven according to the second embodiment of this invention. The description of the same reference numerals as those in Embodiment 1 is omitted. The difference from the first embodiment is that a power switch 25 having a reset function is provided in front of an electric circuit connected to a load and a power supply unit. When the power switch 25 is manually switched to the closed state, the closed state is maintained by the magnet. The power switch 25 can be manually switched to the open state, but when the coil 25a is energized, a repulsive force is generated in the direction to open the contact, and the power switch 25 can be returned to the open state.

About the microwave oven comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.
First, by closing the power switch 25, power is supplied to the AC / DC converter 14 and + 5V is output. In this state, the cooking device is still in a standby state, and the power consumption of the AC / DC converter when the output current of the AC / DC converter 14 is the minimum is the power consumed by the cooking device. Some recent AC / DC converters have a standby power of 10 mW or less when the output current is 0. By reducing the output of the AC / DC converter as much as possible, the power consumption during standby of the cooker is 50 mW or less. It becomes possible to do.

  Next, by opening / closing the door 2, + 5V is supplied to the microcomputer 13 to shift to an operating state. In a normal state where no leakage occurs, the microcomputer 13 turns on and off the relays 11a, 11b, 11c, and 11d in a pre-programmed sequence, controls the high-frequency generator 10a and the heater 10b, and heats the food. Cook. When the state does not change for a predetermined time after cooking is finished, the microcomputer 13 lowers the power holding signal to 0 V level and turns off the power supply unit 17, thereby supplying power to the control means and the leakage determination unit 16. Supply is stopped and a standby state is entered.

Next, the operation when the occurrence of electric leakage is detected will be described. When the relays 11a, 11b, 11c, and 11d are turned on / off and a voltage is applied to the load that is the high-frequency generator and the heating source, the microcomputer 13 immediately turns off the relay and stops the application of the voltage. When the output of the leakage determination unit 16 returns to normal by turning off the relay, the display element 4 is displayed to notify the occurrence of the leakage, inform the user of the occurrence of the leakage, and stop using the cooker. Prompt. In addition, while notifying the occurrence of electric leakage, the notification is continued without entering the standby state. When the load such that the relays 11a, 11b, 11c, and 11d are turned off is in a double-cut state, and the leakage determination unit 16 further determines the occurrence of leakage, the microcomputer 13 immediately turns on the transistor 26. Is output and the coil 25a is energized, thereby opening the contact of the power switch 25.

  As described above, the cooking device according to the present invention can eliminate the power consumption of the leakage detection circuit during standby without impairing the effect of the leakage blocking function for preventing leakage or electric shock. It is equipped with a function, and it is necessary to reduce power consumption during standby. It can also be applied to applications such as home appliances that need to be reduced as much as possible.

External view of the heating cooker in Embodiment 1 of the present invention The circuit diagram of the heating cooker in Embodiment 1 of this invention (A) Timing chart showing the voltage of each part of the activation signal generation unit when the door opening / closing operation is performed in the standby state in the first embodiment of the present invention (b) Door switch on / off logic in (a) Timing chart showing the voltage of each part of the start signal generator when the is opposite Circuit diagram of heating cooker in Embodiment 2 of the present invention Circuit diagram of conventional cooking device

Explanation of symbols

8a Electric circuit 10a High frequency generator (load)
10b Heater (load)
11a, 11b, 11c, 11d Relay (switch)
13 Microcomputer (control means)
14 AC / DC converter (power supply)
15 Zero-phase current transformer (current detector)
16 Electric leakage determination unit 17 Power supply unit 19 Start signal generation unit 20 Door switch 25 Power switch

Claims (7)

A load, a control means for controlling the load, a power supply section of the control means, a power supply section for supplying power from the power supply section to the control means, and a power supply by supplying a signal to the power supply section An activation signal generation unit for starting a power supply, an electric circuit for supplying commercial power to the load and the power supply unit, a current detection unit for detecting an unbalanced current flowing in the electric circuit, and presence or absence of leakage due to a signal from the current detection unit And the control means and the leakage determination unit operate when power supply is started by a signal from the activation signal generation unit during a standby state in which the power supply unit is not supplying power. If the signal of the leakage determination unit is normal, the subsequent operation is continued by continuing the power supply of the power supply unit, and the standby state by stopping the power supply of the power supply unit Specially to be Heating cooker to be. The cooking device according to claim 1, wherein the activation signal generator includes a door switch that operates in conjunction with opening and closing of the door, and generates a signal by opening or closing the door switch. The cooking device according to claim 1, further comprising a switch that opens and closes a connection between the load and the electric circuit, and the control unit opens the switch when a signal from the leakage determination unit is not normal. The cooking device according to claim 1, further comprising a power switch having a reset function for opening and closing an electric path to the load and the power supply unit, wherein the control means opens the power switch when the signal of the leakage determination unit is not normal. vessel. A power switch having a reset function for opening and closing an electric path to the load and the power supply unit, and a switch for opening and closing a connection between the load and the electric circuit, and the control unit is configured to switch the switch when the signal of the leakage determination unit is not normal. The cooking device according to claim 1, wherein the power switch is further opened when the signal of the leakage determination unit is not normal after opening. The cooking device according to any one of claims 3 to 5, further comprising a notification unit, wherein the control unit notifies the occurrence of a leakage by the notification unit when the signal of the leakage determination unit is not normal. vessel. The cooking device according to claim 6, wherein the control means is configured not to stop the power supply of the power supply unit while notifying the occurrence of the electric leakage.