JPH03224517A - heating cooker - Google Patents

Abstract

PURPOSE:To prevent the repetition of a meaningless notice to a user against a single noise by informing abnormality to the user only when the abnormal state of an inverter circuit is generated continuously for a prescribed time. CONSTITUTION:When a power supply voltage is abnormal, the abnormality detecting circuit 12 of a control circuit 11 decides that an inverter circuit 2 is in an abnormal state, and outputs a signal to an oscillation stopping circuit 13 and a timer circuit 14, respectively. Subsequently, the timer circuit 14 operates a timer as the abnormal state of the inverter circuit 2, but in the case this abnormal state is restored within four seconds, the abnormality detecting circuit 12 releases an output signal from its time point. In the case it is not restored, the timer circuit 14 outputs a signal to a display part 23 until the abnormal state is restored and the output signal from the abnormality detecting circuit 12 is released from its time point. In such a manner, as for a single impulse-like noise, it is not informed to a user every time.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a cooking device using induction heating.

BACKGROUND OF THE INVENTION In recent years, cooking appliances using induction heating are required to be able to cook food without being affected by abnormal operation caused by isolated impulse-like power supply noise.

Conventional cooking appliances that use this type of induction heating have abnormal load detection devices, temperature detection devices, or overvoltage detection devices.

Equipped with a protection function device such as a low voltage detection device, the heating display LED lights up during normal heating, and when the protection function device is activated, heating is immediately stopped, and the heating display LED lights up for a certain period of time while heating is stopped. , and then restarts heating again. At this time, if the protective function device has not been deactivated, heating will be stopped again, and while heating is stopped,
The heating indicator LED was turned off for a certain period of time.

Note that if the protective function device is deactivated when heating is restarted, the normal heating state is restored and the heating display LED is turned on again.

Problems to be Solved by the Invention In such conventional heating cookers, the LED lights only when heating, but when the protective function device is activated, the heating stops and starts repeatedly at regular intervals. There was also a problem that the LED would repeatedly turn off and turn on.

The present invention solves the above-mentioned problems by constantly monitoring impulse-like conditions and notifying an abnormality only when an abnormal condition occurs continuously for a certain period of time. The primary purpose of this system is to eliminate meaningless appeals that have little effect on cooking performance to the user by not displaying any abnormal operations.

In addition, the state of the inverter circuit is constantly monitored, and only if an abnormal condition occurs continuously for a certain period of time, heating is forcibly stopped for a certain period of time (for example, about 8 seconds), and an abnormality is notified during that time, so that unnecessary The second purpose is to prevent power consumption and to ensure that only abnormal conditions that affect cooking performance are reported as abnormal.

Means for Solving the Problems In order to achieve the first object, the present invention provides a heating coil for inductively heating a container, an inverter circuit for supplying a high frequency current to the heating coil, and a notification of the heating state of the container. an abnormality detection circuit that detects an abnormal state of the inverter circuit and outputs a signal; and an abnormality detection circuit that outputs a signal when the output of the abnormality detection circuit is not released within a certain time after the abnormality detection circuit outputs the signal. and a timer circuit that outputs a signal, and the notification means notifies the abnormal state until the signal from the abnormality detection circuit is released after receiving the output signal from the timer circuit. It is used as a means.

Furthermore, in order to achieve the second object, in addition to the first problem-solving means, an inhibiting circuit is provided which receives an output signal from the timer circuit and inhibits the oscillation of the inverter circuit for a certain period of time;
A second problem-solving means is that while the prohibition circuit prohibits oscillation of the inverter circuit, the notification means notifies the abnormal state.

Operation The present invention has the above-mentioned first problem solving means, and is capable of detecting an abnormality when the operating state of the inverter circuit is abnormal due to a large fluctuation in the power supply voltage, abnormal oscillation of the inverter circuit, abnormal heating of one component, inappropriate steel, etc. When the detection circuit is activated, the timer circuit is activated by a signal from the abnormality detection circuit, and the signal is output from the abnormality detection circuit for a certain period of time or more, the timer circuit outputs a signal to the notification means, and the notification means A warning of equipment abnormality is given to the user by flashing the lighting elements or by an alarm until the operating state of the inverter circuit returns to normal and the signal from the abnormality detection circuit is released. Thereafter, the inverter circuit is brought into a state where it can oscillate again, and the above contents are repeated.

Further, when the second problem solving means outputs a signal from the abnormality detection circuit for a certain period of time or more.

The timer circuit outputs a signal to the prohibition circuit, and the prohibition circuit forcibly stops the oscillation of the inverter circuit for a certain period of time (approximately 8 seconds). During this time, the notification means warns the user of the abnormality of the equipment by blinking the lighting element or by using an alarm or the like.

After that (about 8 seconds later), the inverter circuit is brought into a state where it can oscillate again, and the above contents are repeated.

EXAMPLE Hereinafter, an example of the first invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, an inverter circuit 2 is connected to a commercial power source 1. In FIG. The inverter circuit 2 includes a rectifier 3 connected to a commercial power supply 1, a capacitor 4 connected to the output terminal of the rectifier 3, a choke coil 6 and a smoothing capacitor 6 connected in series, and a resonant capacitor 7 connected to the smoothing capacitor 6. It is composed of a switching transistor 8 having a built-in diode connected in antiparallel. capacitor 4
and CHIWOKUKOI/L15 constitute a filter circuit. Further, the heating coils /l/9 and 10 are connected in parallel with the resonant capacitor 7 to form a resonant circuit. The control circuit 11 includes an abnormality detection circuit 12 that detects an abnormal state of the inverter circuit 2 by detecting the voltage across the smoothing capacitor e, and an oscillation stop circuit that stops oscillation of the inverter circuit 2 based on the output signal of the abnormality detection circuit 12. 13, a timer circuit 14 that measures the time period during which the inverter circuit 2 is in an abnormal state based on the output signal of the abnormality detection circuit 12, and outputs a signal when the abnormal state continues for a certain period of time; and a switching transistor 8. A drive circuit 15 for driving the.

In this embodiment, the timer time required for the timer circuit 14 to measure the abnormality time of the inverter circuit 2 and output a signal is approximately 4 seconds. Further, the abnormality detection circuit 12 may detect the voltage across the resonant capacitor 7 or the switching transistor 8 to detect an abnormal state of the inverter circuit 2.

Next, in FIG. 2, a storage section 18 for storing a pot 17, which is a container for storing rice, is provided inside the main body 1e.
6 is covered with an upper lid 19 that can be opened and closed freely, and the pot 17 is covered with the upper lid 1.
By opening and closing 9, the item can be taken out. The heating coil 9.1° is for induction heating the pot 17.
A plurality of ferrite cores 21 that absorb leakage magnetic flux are placed on a support stand 2o, and are provided radially below the support stand 2o. The load detection device 22 moves up and down and mechanically detects whether the pot 17 is an appropriate container for cooking rice.
It is provided on the lower surface of the pot 17, and if the pot 17 is inappropriate for cooking, it outputs a signal to the control circuit 11 indicating that the pot 17 is inappropriate.

The control circuit 11 controls the oscillation of the inverter circuit 2, and also controls the display section 23, which is a notification means for notifying the heating state of the pot 17 provided on the upper part of the main body 16.

The operation in the above configuration will be explained. When rice and water are put into the pot 17 and rice cooking starts, the control circuit 11 displays the display section 2.
The rice cooking LED 3 is turned on, and the inverter circuit 2 starts oscillating. If a voltage abnormality occurs in the commercial power supply 1 during rice cooking and a voltage higher than normal is input to the inverter circuit 2, a high voltage is applied to both ends of the smoothing capacitor 8. As a result, the abnormality detection circuit 12 determines that the inverter circuit 2 is in an abnormal state because the power supply voltage is abnormal, and outputs signals to the oscillation stop circuit 13 and the timer circuit 14, respectively. Here, the oscillation stop circuit 13 outputs a signal to the drive circuit 16 to stop the operation of the switching transistor 8, and the drive circuit 16 stops the operation of the switching transistor 8. Then, the abnormality detection circuit 12 continues to output a signal until the voltage of the commercial power supply 1 becomes normal. Note that at this point, the rice cooking LED remains lit.

Then, the timer circuit 14 operates the timer when the inverter circuit 2 is in an abnormal state, but if this abnormal state returns within 4 seconds, the abnormality detection circuit 1
2 cancels the output signal, sets the drive circuit 15 to a driveable state, causes the inverter circuit 2 to oscillate, and turns on the timer circuit 14.
Reset the timer.

Conversely, if the abnormal state of the inverter circuit 2 does not recover within 4 seconds, the timer circuit 14 outputs a signal to the display unit 23 from that point until the abnormal state returns and the output signal from the abnormality detection circuit 12 is released. Output. The display unit 23 turns off the rice cooking LED while receiving the signal from the timer circuit 14.
Flashes every 6 seconds.

As described above, according to the heating cooker of the embodiment of the first invention,
If the abnormal state of the inverter circuit 2 continues for a certain period of time (4 seconds) or more, the control circuit 11 causes the rice cooking LED to blink at intervals of 0.6 seconds from that point until the abnormal state is restored, notifying the user of the abnormality.

Therefore, in response to a single impulse-like noise, the operation of the inverter circuit 2 immediately stops, but after the inverter circuit 2 recovers from its abnormal state, it restarts normal operation, so there is no impact on the rice cooking performance. Since there is no impact, users will not be notified each time. In the above embodiment, the abnormality detection circuit 12 is configured to detect an abnormal voltage of the commercial power supply 1 and detect an abnormal state of the inverter circuit 2. However, the present invention is not limited to this. Nabe 1
The load detection device 22 may detect 7, or may detect an abnormal temperature rise of a component of the inverter circuit 2 (not shown). Further, in the above embodiment, the notification means (display unit) 23 is a rice cooking LED, and is configured to notify an abnormality by blinking, but the same effect can be obtained by using a configuration in which a buzzer or the like is used to notify an abnormality.

Next, an embodiment of the second invention will be described with reference to FIG. Components having the same configuration as the embodiment of the first invention are given the same reference numerals, and the explanation thereof will be omitted.

The control circuit 24 includes an abnormality detection circuit 12 that detects an abnormal state of the inverter circuit 2 by detecting the voltage across the smoothing capacitor 6, and an oscillation stop circuit that stops oscillation of the inverter circuit 2 based on the output signal of the abnormality detection circuit 12. 13, the time period during which the inverter circuit 2 is in an abnormal state is measured based on the output signal of the abnormality detection circuit 12, and when the abnormal state continues for a certain period of time or more, a signal is sent to a prohibition circuit 26 that prohibits the operation of the inverter circuit 2 for a certain period of time. A timer circuit 14 for outputting and a drive circuit 16 for driving the switching transistor 8
It is equipped with

In this embodiment, the prohibition time during which the prohibition circuit 26 prohibits the oscillation of the inverter circuit 2 is approximately 8 seconds;
The timer time for measuring the abnormality time of the inverter circuit 2 and outputting a signal is set to about 4 seconds.

The operation in the above configuration will be explained. When rice and water are put into the pot 17 and rice cooking starts, the control circuit 11 displays the display section 2.
The rice cooking LED 3 is turned on, and the inverter circuit 2 starts oscillating. If a voltage abnormality occurs in the commercial power supply 1 during rice cooking and a voltage higher than normal is input to the inverter circuit 2, a high voltage is applied to both ends of the smoothing capacitor 6. As a result, the abnormality detection circuit 12 determines that the inverter circuit 2 is in an abnormal state because the power supply voltage is abnormal, and outputs signals to the oscillation stop circuit 13 and the timer circuit 14, respectively. Here, the oscillation stop circuit 13 outputs a signal to the drive circuit 15 to stop the operation of the switching transistor 8, and the drive circuit 16 stops the operation of the switching transistor 8. The abnormality detection circuit 12 continues to output a signal until the voltage of the commercial power supply 1 becomes normal. Note that at this point, the rice cooking LED remains lit.

Then, the timer circuit 14 operates the timer when the inverter circuit 2 is in an abnormal state, but if this abnormal state returns within 4 seconds, the abnormality detection circuit 1
2 cancels the output signal, enables the drive circuit 15 to drive, causes the inverter circuit 2 to oscillate, and sets the timer circuit 14 to
Reset the timer.

Conversely, if the abnormal state of the inverter circuit 2 does not recover within 4 seconds, the timer circuit 14 outputs a signal to the prohibition circuit 25 and resets the timer. Then, the prohibition circuit 26 prohibits the operation of the inverter circuit 2 for 8 seconds.

Only for these 8 seconds, the control circuit 24 controls the rice cooking LED on the display section 23.
blinks in 0.5 second increments. After 8 seconds, the prohibition is canceled, the inverter circuit 2 is enabled to oscillate again, and the abnormal state of the inverter circuit 2 is detected by the abnormality detection circuit 12.

As described above, according to the heating cooker of the embodiment of the second invention,
If the abnormal state of the inverter circuit 2 continues for 4 seconds or more, the control circuit 24 will forcibly prohibit the operation of the inverter circuit 2 for about 8 seconds to prevent wasteful power consumption. blinks to notify the user of any abnormalities. Therefore, in response to a single impulse-like noise, the operation of the inverter circuit 2 immediately stops, but after the inverter circuit 2 recovers from its abnormal state, it restarts normal operation, which has no effect on the rice cooking performance. Since there is no notification, the user is not notified each time it occurs. In the above embodiment, the abnormality detection circuit 12 is connected to the commercial power supply 1.
Although the configuration is configured to detect an abnormal voltage of the inverter circuit 2 and detect an abnormal state of the inverter circuit 2, the present invention is not limited to this.
Although not shown, it may be used to detect a pot 17 that is inappropriate for cooking rice, or to detect an abnormal temperature rise in a component of the inverter circuit 2, for example. Further, in the above embodiment, the notification means (display unit) 23 is a rice cooking LED, and is configured to notify an abnormality by blinking, but the same effect can be obtained by using a configuration in which a buzzer or the like is used to notify an abnormality.

As is clear from the explanation of the embodiments above, according to the first invention, the user is notified of the abnormality only when the abnormal state of the inverter circuit occurs continuously for a certain period of time. It is possible to prevent repetition of meaningless notifications to the user regarding one-off noises. Further, according to the second invention, when an abnormal state of the inverter circuit occurs continuously for a certain period of time, heating is forcibly stopped for a certain period of time and an abnormality is notified during that period, so that wasteful power consumption can be prevented. Furthermore, it is possible to reliably notify the user of an abnormality.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a heating cooker according to an embodiment of the present invention;
The figure is a longitudinal cross-sectional view of the heating cooker, and FIG. 3 is a circuit diagram of a heating cooker according to another embodiment of the present invention. 2... Inverter circuit, 9... Heating coil, 10... Heating coil, 12... Abnormality detection circuit, 14... Timer circuit, 17...
... Pot (container), 23 ... Display section (notification means).

Claims (2)

[Claims] (1) A heating coil that inductively heats the container, an inverter circuit that supplies high-frequency current to the heating coil, a notification means that notifies the heating state of the container, and detects an abnormal state of the inverter circuit and outputs a signal. an abnormality detection circuit; and a timer circuit that outputs a signal when the output of the abnormality detection circuit is not released within a certain period of time after the abnormality detection circuit outputs the signal, and the notification means is configured to detect the output of the timer circuit. After receiving a signal, the cooking device is configured to notify an abnormal state until the signal from the abnormality detection circuit is released. (2) A prohibition circuit is provided which prohibits the oscillation of the inverter circuit for a certain period of time in response to the output signal of the timer circuit, and while the prohibition circuit prohibits the oscillation of the inverter circuit, an abnormal state is notified by the notification means. The heating cooker according to claim 1.