JPH02268709A - Heating cooker such as rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a cooking device such as a rice cooker using induction heating.

2. Description of the Related Art Conventional heating cookers using this type of induction heating are equipped with protective function devices such as an abnormal load detection device, a temperature detection device, or an overvoltage or low voltage detection device. When the protection function device is activated by lighting the protection function device 14D, the heating is first stopped, and while the heating is stopped, the heating display LED is turned off for a certain period of time, and then the heating is restarted, but at this time the protection function device is activated. If the functional device has not been deactivated, heating is stopped again, and while heating is stopped, the heating display LKDI is turned off for a certain period of time.

Note that when heating is restarted, if the protective function device has been deactivated, the normal heating state is restored and the heating display LE
This makes D light up again.

Problems to be Solved by the Invention In such a conventional configuration, the L
The ED lights up, but while the protective function device is operating,
Heating is repeatedly stopped and started at regular time intervals, and the LED is also turned off and turned on repeatedly.

The present invention solves these problems by constantly monitoring the operation of the inverter circuit and forcibly heating it for a certain period of time (for example, about 8 seconds) only when abnormal operation occurs two or more times in a row. In addition to preventing unnecessary power consumption by stopping the system, it also displays abnormal operation by ignoring it at least the first time, especially when abnormal operation is caused by one-off impulse-like power supply noise that is common in daily life. The purpose is to eliminate meaningless A/VF that has little impact on performance for users.

Means for Solving the Problems A heating cooker such as a rice cooker according to the present invention includes a heating coil for inductively heating a container, an inverter circuit for supplying a high-frequency current to the heating coil, and a control circuit for controlling the operation of the inverter circuit. , a display section having a lighting element that displays the heating state of the container, and the control circuit includes an abnormality detection circuit that detects abnormal operation of the inverter circuit and outputs a signal, and receives an output signal of the abnormality detection circuit. an oscillation stop circuit that stops the oscillation of the inverter circuit, a start-up delay circuit that delays the start of re-oscillation of the inverter circuit for a certain period of time after the oscillation of the inverter circuit has stopped; a counting circuit that counts the number of signals output by the abnormality detection circuit and outputs a signal when the number of counted signals becomes 2 or more; and a counting circuit that receives the output signal of the counting circuit and causes the inverter circuit to oscillate for a certain period of time. The display device has a prohibition circuit that prohibits oscillation of the inverter circuit, and causes the lighting elements of the display section to blink while the prohibition circuit prohibits oscillation of the inverter circuit.

Function The heating cooker such as a rice cooker of the present invention has a protective function when the operating state of the inverter circuit is inappropriate due to large fluctuations in the power supply voltage, abnormal oscillation of the inverter circuit, abnormal overheating of parts, inappropriate steel, etc. The operation of the device stops the oscillation of the inverter circuit and protects the inverter circuit components. Then, the control circuit outputs a signal so that the inverter circuit re-oscillates after a certain delay time (one second).

After this time, if the inverter circuit continues to oscillate normally, the display section will not display an abnormality by blinking the lighting elements or the like. However, even if the inverter circuit oscillates again, it is again in an inappropriate operating state and the protective function device is activated again, causing the inverter circuit to stop oscillating again! If the inverter is turned off, the counting circuit outputs a signal, and the inhibiting circuit forcibly stops the oscillation of the inverter circuit for a certain period of time (approximately 8 seconds).

During this time, the display section warns the user of the abnormality of the device by flashing the lighting elements or by issuing an alarm.

Thereafter (about 8 seconds later), the control circuit outputs a signal so that the inverter circuit re-oscillates, and the above contents are repeated.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

In Fig. 2, reference numeral 1 denotes a main body of a jar rice cooker using induction heating, which is an embodiment of the present invention. The steel 3 ((-upper lid 9
It can be taken out by opening and closing.

4.5 is a heating coil μ for inductively heating the steel 3, which is placed on a support stand 6, and a plurality of ferrite cores are radially provided on the lower side of the support stand 6 to absorb leakage magnetic flux. There is.

1o is a load detection device that moves up and down and mechanically detects whether the pot 3 is an appropriate container for cooking rice, and is installed on the bottom of the pot 3. For example, a signal indicating that the pot is inappropriate is output to the control unit 13. The control section 13 controls the oscillation of the inverter circuit section 8 provided at the bottom of the main body 1 that supplies high-frequency current to the heating coil 4.6, and also controls the display section 11 provided at the top of the main body 1.

In FIG. 2, 12 is a commercial power supply and the inverter circuit 8
is connected. The inverter circuit 8 is connected to the commercial power supply 12
A rectifier 14 connected to the output terminal of the rectifier 14 and a choke coil/
v16 and smoothing capacitor 177! :, a switching transistor that includes a resonant capacitor 18 connected to a smoothing capacitor 17 and a diode connected in anti-parallel.
It consists of 19. The capacitor 15 and the choke coil 16 constitute a filter circuit.

The heating coils/v4 and 6 are connected in parallel with the resonant capacitor 18 to form a resonant circuit.

The control circuit 13 includes an abnormality detection circuit 20 that detects abnormal operation of the inverter circuit 8 by detecting the voltage across the smoothing capacitor 17 and the voltage between the collector and emitter of the switching transistor 19, and an abnormality detection circuit 2o.
an oscillation stop circuit 21 that stops the oscillation of the inverter circuit 8 based on an output signal from the inverter circuit 8; and a startup delay circuit 22 that delays the oscillation of the inverter circuit 8 by a certain period of time after the oscillation of the inverter circuit 8 is stopped until it is restarted.
The output signal of the abnormality detection circuit 20 is used to count the number of abnormal operations of the inverter circuit 8 within a certain period of time, and when the number becomes 2 or more, a prohibition circuit 24 is configured to prohibit the operation of the impark circuit 8 for a certain period of time. It includes 23 counting circuits that output signals and a drive circuit 25 that drives the switching transistor 19.

The time that the start-up delay circuit 22 delays from when the inverter circuit 8 stops oscillating until it restarts is set shorter than the time that the prohibition circuit 24 prohibits the inverter circuit 8 from oscillating.

Also, during the time when the counting circuit 23 is counting the abnormal state of the inverter circuit 8, the startup delay circuit 22 is counting the abnormal state of the inverter circuit 8.
The delay time from when the oscillation stops until it restarts is set to be much longer.

In this embodiment, the delay time is about 1 second, the prohibition time is about 8 seconds,
The counting time is about 3 seconds.

In the above configuration, when rice and water are put into the pot 3 and rice cooking is started, the control circuit 13 controls the rice cooking L on the operation display section 11.
The CD is lit and the inverter circuit starts oscillating.

If impulse-like noise is applied to the commercial power supply 12 during rice cooking, the noise is superimposed on the voltage across the smoothing capacitor 17 and a high voltage is applied, causing the inverter circuit 8 to abnormally oscillate, causing the collector of the switching transistor 19 to The voltage increases abnormally.

Then, the abnormality detection circuit 20 determines that the operation of the inverter circuit 8 is abnormal, and outputs signals to the oscillation stop circuit 21 and the counting circuit 23, respectively.

Here, the oscillation stop circuit 21 outputs a signal to the drive circuit 26 to stop the operation of the switching transistor 19, and the drive circuit 25 outputs a signal to the drive circuit 26 to stop the operation of the switching transistor 19.
Stop the operation of 9. Then, approximately one second after the inverter circuit 8 stops operating, the drive circuit 26 sends a signal to the switching transistor 19 to restart the drive, and the inverter circuit 8 starts operating again.

During this time, the rice cooking LICD is lit! There is even.

In addition, the counting circuit 23 counts this time as one abnormal operation of the inverter circuit 8, but if the inverter circuit 8 continues to operate normally for 3 seconds thereafter, the counted one time is reset as 0 times again. be done.

When the inverter circuit 8 restarts operation, the commercial power supply 12
If impulse-like noise still continues to build up, each circuit in the control circuit 13 repeats the above steps to stop the operation of the inverter circuit 8, and after about 1 second, drives the inverter circuit 8 again. shall be. However, since this clock counting circuit 23 counts the abnormal operation of the inverter circuit 8 twice in a row, it outputs all the signals to the prohibition circuit 24, and the prohibition circuit 24 prohibits the operation of the inverter circuit 8 for about 8 seconds. . Only during these 8 seconds, the control circuit 13 causes the rice cooking LED on the display section 11 to blink every 0.5 seconds.

After about 8 seconds, the inhibition is canceled and the activation delay circuit 22
The inverter circuit 8 is restarted by the drive circuit 26,
The rice cooking LED also lights up.

As explained above, if the inverter circuit 8 abnormally operates twice in three seconds, the control circuit 13 forcibly prohibits the operation of the inverter circuit 8 for about eight seconds.

During this time, the rice cooking LICD blinks at 0.6 second intervals to notify the user of the abnormality.

Therefore, in response to a single impulse-like noise, the operation of the inverter circuit 8 immediately stops, but the startup delay circuit 22 causes the normal operation to start all the time after one second, so there is no effect on the rice cooking performance. Therefore, we do not notify users one by one.

In the above embodiment, the abnormality detection circuit 20 has a configuration for detecting an abnormal voltage of the inverter circuit 8 (-), but the present invention is not limited to this. The effects of the present invention can also be achieved as a device that detects abnormal temperature rises in inverter circuit components.

Furthermore, although the counting circuit 23 detects abnormal operation of the inverter circuit 8 by a number of times, the invention is not limited to this.
The effects of the present invention can also be obtained by detecting the operating state of the inverter circuit 8 after a certain period of time, for example, 3 seconds after the first abnormality detection, and monitoring whether or not the inverter circuit 8 is operating abnormally. The goal is to achieve the following.

Effects of the Invention As will be clear from the description of the embodiments below, the present invention provides the following effects.

(1) Since the heater is notified only when abnormal operation of the inverter circuit occurs at least twice or more in a row, it is possible to prevent meaningless notifications from being given to the user in response to one-off noises that are common in everyday life.

(2) When abnormal operation of the inverter circuit occurs continuously, heating is forcibly stopped for a certain period of time, so wasteful power consumption can be prevented.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram of a jar rice cooker showing one embodiment of the present invention, and FIG. 2 is a sectional view thereof. 3... Container, 4.6... Heating coil,
8...Inverter circuit, 11...Display section, 13...Control circuit, 20...Abnormality detection circuit, 21...Oscillation stop Circuit, 22...
-...Start-up delay circuit, 23...Counting circuit, 24
...Prohibited circuit. Name of agent: Patent attorney Shigetaka Awano TL or 1 person 3
--Ichishibuima y-yo boiling coil

Claims (1)

[Claims] A heating coil that inductively heats the container, an inverter circuit that supplies high-frequency current to the heating coil, a control circuit that controls the operation of the inverter circuit, and a display section that has a lighting element that displays the heating state of the container, The control circuit includes:
an abnormality detection circuit that detects abnormal operation of the inverter circuit and outputs a signal; an oscillation stop circuit that stops oscillation of the inverter circuit in response to an output signal of the abnormality detection circuit; and a re-oscillation start after stopping the oscillation of the inverter circuit. a start-up delay circuit that delays the signal for a certain period of time; and a start-up delay circuit that counts the number of signals output by the abnormality detection circuit within a certain period of time after the abnormality detection circuit outputs the signal, and when the counted number of signals becomes 2 or more. It has a counting circuit that outputs a signal, and a prohibiting circuit that receives the output signal of the counting circuit and prohibits the oscillation of the inverter circuit for a certain period of time, and displays the display while the prohibiting circuit prohibits the oscillation of the inverter circuit. A heating cooker such as a rice cooker that has a flashing lighting element.