JPH0229215A - 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] [Objective of the Invention] (Field of Industrial Application) The present invention relates to a rice cooker equipped with a power outage compensation function, and particularly relates to a rice cooker that is equipped with a power outage compensation function, and in particular, when the power supply is stopped due to a power outage, etc., noise input can be normalized. This relates to a rice cooker that is equipped with a function that does not misjudge that the power has returned.

(Prior art) In conventional rice cookers, for example, when the rice cooking operation is set on a timer, even if a long power outage occurs, after the power is restored, the rice cooker automatically returns to the operating setting state before the power outage. Some devices are equipped with a power outage compensation function that will restore power. The reason for this feature is that, for example, if you set a timer at night before going to bed so that the rice is cooked in time for breakfast, it will prevent a long power outage while you are sleeping. However, if you want to make sure that you can eat rice at breakfast time, or if you turn off the power after cooking rice in the kitchen, take the rice cooker to a meal, and then turn it on again in the kitchen after the meal is finished, This is to meet the demand for automatically setting the heat retention state to reliably keep leftover rice warm.

In order to realize such a function, the rice cooker maintains the III all system in an operating state and stores set information even when the power supply is stopped due to a power outage, etc. The control system is equipped with a backup power source and power consumption reducing means for bringing the control system into a low power consumption state in order to maintain power supply from the backup power source for a long time. In the low power consumption state, the display current from the control system to the display, the control current to the heater control relay,
The current for temperature detection to each temperature sensor and the current for reading key operation to the key input circuit are turned off to reduce the power consumption of the backup power supply.

(Problem to be solved by the invention) Nowadays, there are more opportunities to install devices equipped with inverter power supplies in ordinary homes, and the environment is susceptible to the effects of electromagnetic noise generated by such devices. . For this reason, with conventional rice cookers, when the power supply is interrupted,
If the above electromagnetic noise is input while the control system is in a low power consumption state and activated by a backup power supply, it will misjudge this as a power return signal, and the system will stop supplying power. Despite this, the control system sometimes returns to normal operation in a high power consumption state.

However, during operation using the backup power source, if the control system returns to the normal high power consumption state 65 due to a misjudgment as shown in FIG. 6, the power consumption of the backup power source will rapidly increase.

For example, if the current consumption is 50 μΔ in the low power consumption state, but it is 50 mA in the 'i:4 low power consumption state, the power will decrease 1000 times faster. Then, a backup power source that is supposed to last 24 hours could run out in 1 minute and 30 seconds. If the power consumption of the backup electric wire is accelerated in this way, the rice cooker will not be able to cope with the power supply interruption for a predetermined period of time, and after the normal power supply is restored, the rice cooker will automatically return to the setting state before the power supply interruption. There was a problem that it became impossible to restore the system.

This invention was made based on the above circumstances, and when the control system is set to a low power consumption state and an operating state by a backup power supply when the power supply is stopped, the restoration of the normal power supply is performed using noise input. It is an object of the present invention to provide a rice cooker that can be clearly distinguished and can always appropriately respond to power supply interruption within a predetermined period of time.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a system in which, when the power supply from the AC power supply is stopped, the control system is brought into operation by the backup power supply means in a low power consumption state. The main feature of the rice cooker is to include a power return detection means for detecting the return of power supply from the AC power supply in distinction from noise input when the control system is in an operating state by the backup power supply means.

(Function) In the above configuration, when the control system is in an operating state by the backup power supply means, the power supply return detection means detects the return of normal power supply, clearly distinguishing it from noise input.

Therefore, the rice cooker always appropriately responds to power supply interruption within a predetermined period of time, and after normal power supply is restored, the rice cooker reliably operates in the setting state before the power supply was stopped.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 5. This embodiment is described for the case where the stoppage of power supply occurs due to a power outage.

First, to explain the configuration of the rice cooker, in FIG. 1, 6 is a commercial AC power supply, 7 is a rice cooking heater, 8 is a heat-retaining heater, and 10 is a control tC consisting of a microcomputer that constitutes a control system (control circuit). This control IC10 has built-in means such as an energization counter constituting a power failure occurrence detection means and a pulse interval counter constituting a power failure recovery detection means.

11 is a display circuit, 12 is a key input circuit, and 13 is a buzzer circuit. Signals from the operating section operated by the user are sent from the key input circuit 12 to the input port I N of the control ICIO.
Information such as each stroke, clock, timer, etc. is output to the display circuit 11 from the output port 0LJT4.

In addition, to notify when keys are pressed or when rice cooking is completed, etc.
A notification command signal is output from the output boat 0UT5 to the buzzer circuit 13.

When cooking rice, the control IC 10 outputs
According to the output signal from 1~0UT2, relay coil 9
a is energized or deenergized, relay contact 9b is turned on/off, and rice cooking heater 7 is set to a required heat generation state. In addition, when keeping warm, the phototriac 14 and the triac 15 are activated according to the output signal from the output boat OUT 3.
The electric current of the series circuit of the heat retention heater 8 and the rice cooking heater 7 is controlled intermittently through the heat retention heater 8 and the rice cooking heater 7, so that the rice is kept warm at a constant temperature. Humidity detection during cooking or keeping warm rice is performed using the analog input board AI, which detects a voltage corresponding to a change in the resistance value of the thermistor 16 that is in thermal contact with the pot in the rice cooker.
It is detected by inputting it to N.

Reference numeral 17 denotes a voltage dividing resistor for creating a voltage corresponding to a change in the resistance value of the thermistor 16.

18 is a large capacity capacitor, 19 is a resistor, and the large capacity capacitor 18 and one resistor constitute a backup power supply means. That is, when power is supplied from the commercial AC power supply 6, the [ )C
The voltage is supplied to the large capacity capacitor 18 via the constant power supply circuit 23.
is charged. When the power supply is stopped due to a power outage, etc., the charging voltage is used as a backup voltage by resistor 1.
Control ICl0 through 9! It is designed to be supplied to the control system of In addition, a diode 24 and a resistor 25
．． 26, 27, a capacitor 28, and a transistor 29 constitute a synchronization signal generation circuit 30, and this circuit 30 generates a synchronization signal synchronized with the input waveform from the commercial AC power supply 6. This synchronization signal is input from the input port IN1 to the control IC 10 as a signal for detecting the occurrence of a power outage or the like.

The crystal sensor 31 and capacitors 32 and 33 connected to the control IC 10 are oscillation circuit components that generate a signal of, for example, 4 MHz for the control IC 10 to operate at normal speed. , also the boat XTIN.

Crystal oscillator 34 and capacitor 3 connected to XTOUT
5.36 is an oscillation circuit component that produces, for example, a 32KH2 signal when the control IC 10 is operated in a low power consumption state.

Next, the operation will be explained using timing charts such as the O-diagrams in FIGS. 2, 3, and 4 and the signals in FIG. 5. Figure 2 is a flowchart showing a power outage detection routine that is part of the main routine, Figure 3 is the first interrupt routine that is activated every time a synchronization signal is input, and Figure 4 is the first interrupt routine that is activated every 1ms. This is the second interrupt routine to be executed.

For example, when the power supply is stopped due to a power outage or the like in a state where the rice cooking operation is currently set on a timer, the operation for detecting the occurrence of a power outage will be explained.

In the power outage detection routine shown in Figure 2, 1/100
Every sec (=10m5) (step 41), the value of the energization counter in the control ICl0 is counted up by one (step 42), and when the count value becomes 4 or more, it is determined that a power outage has occurred ( Step 4
3 Yes).

That is, in the timing chart of FIG. 5, before time t1, the commercial AC power supply 6 is in the power supply state (hereinafter also referred to as energized), so the synchronization signal generation circuit 30 generates a synchronization signal, which is transmitted to the control ICl0. Enter into input port INI.

Then, each time this synchronization signal is input, that is, when the power frequency is 50 Hz, every 2 OrTT S e C, and when 601-1 z, 16.7 m5ec
Each time, the first interrupt routine shown in FIG. 3 is activated. In this first interrupt routine, since the power flag shown in step 46 is energized (NO), the value of the power supply counter is set to zero (step 4
7). Therefore, during this energization period, the value of the energization counter will never exceed 4, and it will not be determined that a power outage has occurred.

Then, at time t1, when a power outage occurs, the value of the energization counter increases by 1 every 1/100 seconds, as described above.
On the other hand, since the synchronization signal is no longer generated, the first interrupt routine is not activated, and therefore the operation to zero the energization counter is no longer performed.

In this way, when 4/100 seconds have passed since time t1, it is determined that a power outage has occurred, as described above (
FIG. 2, Step 43: Yes). This point in time is time t2 in FIG. When it is determined that a power outage has occurred, the power flag is changed from the energized state to the power-off state as a process for entering a power outage state (step 44), and the control I is changed as a process for reducing power consumption (step 45).
Each input/output boat in Cl0 0UT1.0UT2.0
UT3.0UT4.0UT5 and IN2 are set to high impedance state, and the temperature detection current and relay 9 are set to high impedance state.
a control current, a control current of the phototriac 14,
Processing is performed to eliminate the display current to the display circuit 11, the buzzer drive current to the buzzer circuit 13, the key operation reading current to the key input circuit 12, etc., and the control IC
l0 itself is switched from operation using a high oscillation frequency signal from the crystal oscillator 31 or the like to operation using a low oscillation frequency signal from the crystal oscillator 34 or the like.

Through the above processing and operation, the time t2 when a power outage was detected
Thereafter, the control system is placed in a low power consumption state, and operates during a long power outage using only the charging power of the capacitor 18 serving as a backup power source.

Next, a power failure recovery detection operation during a power failure operation as described above will be explained. In FIG. 5, when the power is restored from the power outage at time t9, the synchronization signal generation circuit 30
A synchronizing signal is generated at , which is input to the input port INI of the control IC 10 . By inputting this synchronization signal, the first interrupt routine shown in FIG. 3 is activated each time the signal is input. In this first interrupt routine, time t
At step 9, the power flag at step 46 is in a power outage state, so the power outage counter is incremented by one (step 48). This power outage counter was initially set to zero,
Therefore, it is set to 1 by the first synchronization signal (Yes in step 4).

With this operation, the pulse interval counter as a pulse interval (pulse period) detection means is set to zero (step 50).
, lm5eC, the second interrupt routine shown in FIG.
The occurrence of this interrupt is allowed so that the interrupt routine for each is activated (step 51). In this interrupt routine every 1 m5 ec, the pulse interval counter is counted up by 1 every 1 m5 eC (step 60), however, the upper limit of the count value is 30 t-
Yes (step 61.62).

While the count-up operation of the pulse interval counter is in progress, a second synchronization signal is input to the input port IN1 of the control IC 10, thereby restarting the first interrupt routine of FIG. Similarly to the above, the power supply flag in step 46 indicates a power outage state, so the value of the power outage counter becomes 2. Therefore, since the count value is not 1 (No in step 49>, the count value of the pulse interval counter is determined in step 52. Therefore, if this count value is between 15 and 22, the input port The input signal to 1 is determined to be a signal correctly synchronized with the power supply frequency (Yes), and if it has a value other than the above, it is determined to be an asynchronous signal (NO).

Then, as shown in the example timing chart of FIG. 5, if the interval from time t9 to the next synchronization signal is smaller than the predetermined interval, the value of the power outage counter is set to zero again (step 53), and 1m5ec Interrupts are prohibited from occurring (step 54).

Subsequently, as shown in FIG. 5, when a signal synchronized with the power supply frequency is input to the input port INI, the first interrupt routine similar to the above is activated, and the second synchronization signal , the value of the power failure counter in step 48 becomes 2. At this time, the value of the pulse interval counter is
Since the value is between 15 and 22, after setting the pulse interval counter to zero (step 55), it is determined whether the value of the power outage counter is 4 or more (step 56).
). At this time, as described above, the value of the power outage counter is 2, so this interrupt processing is ended. After this, when the synchronization signal is input twice to the input port IN1, that is, at the time t to in FIG. 4, normal power outage recovery (power recovery)
It is determined that interrupt generation is prohibited every 1m5eC (
Step 57).

As a process (step 58) for recovering from the power outage, the power flag is changed from the power-off state to the energized state, and the value of the power outage counter is set to zero. Further, as a process for restoring power consumption, contrary to the process for reducing power consumption performed in step 45 in FIG. 2, necessary input/output ports are turned on, and the control IC 10 itself operates is returned to the high oscillation frequency signal operation by the crystal oscillator 31.

As mentioned above, when recovering from a power outage, 1 shown in Figure 4
By interrupt generation processing every m5eC and pulse interval detection processing in step 52 in Fig. 3, the control IC
It is confirmed that the period of the input signal to the input port INI at l0 is synchronized with the power supply frequency, and further, by the determination process of step 56 in FIG. Based on the results of this confirmation, the system detects when a power outage returns.

Therefore, even if a signal such as electromagnetic noise that is not synchronized with the power supply frequency is input to the input port IN1, or even if the interval between two noise pulses is coincidentally synchronized with the power supply frequency, in the case of noise, Since the above synchronized states are not consecutive, it can be determined that the power outage state continues.
This figure shows a case where noise occurs during the period t4 or from t6 to t7.
With the pulse interval detection process, the pulse interval is 15 to 22
Even if it is determined that the noise interval is not between m5ec, or even if one of the noise intervals happens to have a value between the above values, the determination process in step 56 determines that this is not continuous. The process for restoring power consumption shown in step 59 is not performed, and the control system continues to be operated by the backup power supply means in a low performance power state.

On the other hand, as shown in the conventional example in FIG. 6, when electromagnetic noise etc. is applied to the input port INI, if this is mistakenly recognized as a power failure recovery signal and processing for power failure recovery is performed,
What about the control system? 3.The charging power of the backup power supply means is transferred to the power consumption state before the normal power outage recovery is performed.
It will be consumed quickly.

[Effects of the Invention] As explained above, according to the present invention, when the power supply is stopped and the control system is in the operating state by the backup power supply means, the power supply return detection means detects the return of normal power supply. Since it is detected clearly from noise input, even when used in a noisy environment, it is possible to always respond to power supply interruptions within a predetermined period of time, and there is no need to worry about the restoration of normal power supply. This has the advantage that it can be operated reliably in the setting state before the power supply was stopped.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the rice cooker according to the present invention, in which FIG. 1 is a circuit diagram, FIG. 2, FIG. 3, and FIG.
The figure is a flowchart for explaining the operation, FIG. 5 is a timing chart without showing signals of each part, and FIG. 6 is a timing chart for explaining the operation of the conventional rice cooker. 6: Commercial AC power supply, 7: Rice cooking heater, 8: Warming heater, 10: Control IC with built-in power return detection means. 182: Large-capacity capacitor constituting backup power supply means; 30: Synchronous signal generation circuit.

Claims (2)

[Claims] (1) In a rice cooker in which the control system is maintained in an operating state by a backup power source means in a low power consumption state when power supply from an AC power source is stopped, when the control system is in an operating state by the backup power source means, A rice cooker characterized by having a power supply return detection means for detecting the return of power supply from an AC power source, distinguishing it from noise input. (2) The power return detection means detects a synchronization signal synchronized with the input waveform from the AC power supply, counts the number of consecutive inputs of the synchronization signal in a predetermined cycle, and when the counted value is equal to or greater than a predetermined number, Claim 1 characterized in that the return of power supply from the AC power source is detected separately from noise input.
The rice cooker mentioned.