JPH0334721B2 - - Google Patents

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) Conventional rice cookers have a system in which, 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 allows recovery. The reason for this feature is that, for example, if you set the timer at night before going to bed so that the rice is cooked in time for breakfast, if there is a long power outage while you are sleeping, For example, if you want to make sure that you can eat rice at breakfast time, or after cooking rice in the kitchen, turn off the power, take the rice cooker to the dining table, and then turn it on again in the kitchen after the meal is finished. This is to meet the demand for ensuring that leftover rice is kept warm by setting the heat retention state.

In order to realize this kind of function, the rice cooker has a control system that keeps its control system in operation and stores the set status even when the power supply is stopped due to a power outage, etc. In addition, a backup power source and power consumption reducing means for bringing the control system into a low power consumption state are provided 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 temperature detection current to the temperature detector, the key operation reading current to the key input circuit, etc. is turned off to reduce the power consumption of the backup power supply.

(Problems to be Solved by the Invention) Nowadays, there are more opportunities to install devices equipped with inverter power supplies and the like in ordinary homes, and the environment is susceptible to the effects of electromagnetic noise generated from such devices. For this reason, in the case of conventional rice cookers, if the above electromagnetic noise is input when the control system is set to a low power consumption state and activated by a backup power supply when the power supply is stopped, There have been cases in which the control system has been mistakenly judged to be a power return signal, and the control system has returned to normal operation in a high power consumption state even though the power supply has been stopped.

However, during operation using the backup power source, as shown in FIG. 6, if the control system returns to the normal high power consumption state 65 due to an erroneous judgment, the power consumption of the backup power source will rapidly increase. For example, if the current consumption was 50μA in the low power consumption state, but it was 50mA in the high power consumption state, the power will decrease 1000 times faster, and for example, the current consumption will last 24 hours in the low power consumption state. It is possible that the backup power supply that was supposed to be used could run out in 1 minute and 30 seconds. If the power consumption of the backup power supply is accelerated in this way, the rice cooker will no longer be able to cope with a power outage 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 stopped. 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 that the rice cooker is provided with 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, the power return detection means
When the control system is energized by the backup power supply means, the return of normal power supply is detected distinctly from noise input.

Therefore, the rice cooker always responds appropriately to power supply interruption within a predetermined period of time, and after normal power supply is restored, it operates reliably 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 Figure 1,
Reference numeral 6 denotes a commercial AC power supply, 7 a rice cooking heater, 8 a heat retention heater, and 10 a control IC consisting of a microcomputer that constitutes a control system (control circuit). Various means such as a pulse interval counter constituting the power failure recovery detection means are built-in. 11 is a display circuit, 12 is a key input circuit, 13
is a buzzer circuit, and the signal from the operation section operated by the user is sent from the key input circuit 12 to the control IC.
It is input to 10 input ports IN2, and each process,
Information such as clock and timer time is output from the output port.
The signal is output from OUT4 to the display circuit 11. Furthermore, a notification command signal is outputted from the output port OUT5 to the buzzer circuit 13 in order to notify when a key is operated or when rice cooking is completed.

During rice cooking, the relay coil 9a is energized or deenergized according to the output signal from the output port OUT2 of the control IC 10, the relay contact 9b is turned on/off, and the rice cooking heater 7 is set to the required heat generation state. Ru. In addition, when keeping the rice warm, the current of the series circuit of the warming heater 8 and the rice cooking heater 7 is controlled intermittently through the phototriax 14 and the rice cooker heater 7 according to the output signal from the output port OUT3, and the rice is kept warm at a constant temperature. It is becoming more and more common. Temperature detection during cooking or keeping warm rice is detected by inputting a voltage corresponding to the resistance change of the thermistor 16, which is in thermal contact with the pot in the rice cooker, to the analog input port AIN. It's summery. 17 is thermistor 1
This is a voltage dividing resistor for creating a voltage corresponding to the change in resistance value of 6.

18 is a large capacity capacitor, 19 is a resistor,
This large capacity capacitor 18 and resistor 19 constitute a backup power supply means. That is, when power is supplied from the commercial AC power supply 6, the transformer 2
A DC voltage that is rectified by a rectifier circuit having a full bridge configuration of diodes 22 is charged to a large-capacity capacitor 18 via a constant power supply circuit 23. When the power supply is stopped due to a power outage or the like, the charging voltage is supplied as a backup voltage to the control system such as the control IC 10 via the resistor 19. In addition, a diode 24, resistors 25, 26, 27, and a capacitor 28
A synchronizing signal generation circuit 30 is configured by the transistor 29 and the transistor 29, and this circuit 30 connects the commercial AC power supply 6.
A synchronization signal is generated that is synchronized with the input waveform from the input waveform. This synchronization signal is input to the control IC 10 from the input port IN1 as a signal for detecting the occurrence of a power outage or the like.

Crystal oscillator 31 and capacitors 32 and 3 connected to ports XIN and XOUT of control IC 10
3 is an oscillator circuit component that produces, for example, a 4MHz signal for the control IC 10 to operate at normal speed, and also ports XTIN and XTOUT.
crystal oscillator 34, capacitors 35, 3
Reference numeral 6 denotes an oscillation circuit component that generates, for example, a 32KHz signal when the control IC 10 is operated in a low power consumption state.

Next, the operation will be explained using the flowcharts shown in FIGS. 2, 3, and 4 and the timing chart of each signal and the like shown in FIG. 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 a flowchart that is activated every 1ms. This is the second interrupt routine that is activated.

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

In the power outage detection routine shown in Figure 2, 1/
Every 100 seconds (=10ms) (step 41), the value of the energization counter in the control IC 10 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 ( Yes on step 43). 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 IC 10. Input to input port IN1 of. Then, each time this synchronization signal is input, that is, every 20 msec when the power frequency is 50 Hz, and every 20 msec when the power frequency is 60 Hz,
The first interrupt routine shown in FIG. 3 is activated every 16.7 msec. In this first interrupt routine, since the power flag shown in step 46 is energized (No), the value of the energization counter is set to zero (step 47). 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 t ₁ , when a power outage occurs,
As mentioned above, the value of the energization counter is incremented by one every 1/100 seconds, and on the other hand, since the synchronization signal is no longer generated, the first interrupt routine is not activated, and therefore the energization counter is set to zero. No action will be taken. In this way, when 4/100 seconds have passed since time t ₁ , it is determined that a power outage has occurred, as described above (see step 43 in Figure 2).
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 to enter the power outage state (step 44), and the control is changed as a process to reduce power consumption (step 45).
Each input/output port OUT1, OUT in IC10
2, OUT3, OUT4, OUT5, and IN2 are set to a high impedance state, and the temperature detection current, the control current of the relay 9a, the control current of the phototriax 14, the display current to the display circuit 11, and the buzzer circuit 13 are respectively transmitted. Processing is performed to eliminate the buzzer drive current to the key input circuit 12 and the key operation reading current to the key input circuit 12.
The device itself is switched from operation using a high oscillation frequency signal from the crystal resonator 31 or the like to operation using a low oscillation frequency signal from the crystal resonator 34 or the like.

Through the above processing and operation, at time t ₂ when a power outage is detected, the control system is placed in a low power consumption state, and the large capacitor 1 is used as a backup power source.
Operation during a long power outage can be performed using only the charging power of 8.

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 , a synchronizing signal is generated in the synchronizing signal generating circuit 30 after this time _t9 , and this signal is input to the input port IN1 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, the power flag in step 46 is in a power-off state at time _t9 , so
The power outage counter is incremented by one (step 48). This power outage counter is initially set to zero, so the first synchronization signal causes the power outage counter to become zero.
(Yes in step 49). As a result of this operation, the pulse interval counter as a pulse interval (pulse period) detection means is set to zero (step 50), and the second interrupt routine shown in FIG. 4, which is an interrupt routine every 1 msec, is activated. Interrupt generation is permitted (step 51). this
In the 1 msec interrupt routine, the pulse interval counter is incremented by 1 every 1 msec (step 60). However, the upper limit of the count value is 30 (steps 61 and 62).

While the count-up operation of the pulse interval counter is in progress, the input port of the control IC 10
A second synchronization signal is input to IN1, thereby restarting the first interrupt routine of FIG. As before, the power flag in step 46 indicates a power outage, so the value of the power outage counter is 2.
becomes. 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. If this count value is between 15 and 22, the input signal to input port 1 is determined to be a signal correctly synchronized with the power supply frequency (Yes), and if it is a value other than the above, it is determined to be an asynchronous signal. Judgment is made (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). Generation of interrupts every 1 msec is prohibited (step 54).

Subsequently, as shown in FIG. 5, when a signal synchronized with the power supply frequency is input to the input port IN1, the first interrupt routine similar to the above is activated, and with 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 between 15 and 22, so after the pulse interval counter is set to zero (step 55), the value of the power failure counter is 4.
It is determined whether or not this is the case (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, the synchronization signal continues to be input to the input port IN.
1 twice, that is, t ₁₀ in Figure 5.
At this point, perform the same operation as above and proceed to step 5.
If the value of the power outage counter reaches 4 in step 6, it is determined that the power outage has returned normally (power recovery).
Disable interrupt generation every 1msec (step
57).

After this, processing for power outage recovery (step 58)
As a result, the power flag is changed from the power-off state to the power-on state, and the value of the power outage counter is set to zero. In addition, 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.
The operation of the control IC 10 itself is controlled by the crystal oscillator 3.
1 to return to high oscillation frequency signal operation.

As mentioned above, upon recovery from a power outage, the input signal to the input port IN1 of the control IC 10 is generated by the interrupt generation process every 1 msec shown in FIG. 4 and the pulse interval detection process in step 52 in FIG. It is confirmed that the cycle of
The system confirms that the power supply has lasted several times, and detects a power outage recovery based on the results of this confirmation.

Therefore, even if a signal such as electromagnetic noise that is not synchronized with the power supply frequency is input to input port IN1, or even if the interval between two noise pulses happens to be synchronized with the power supply frequency, in the case of noise, Since the synchronized state does not continue any longer, it can be determined that the power outage state continues. The timing chart in Figure 5 shows t ₃ to _{t 4} or
The case where noise occurs during the period t ₆ to _{t 7} is shown, but during this period, the pulse interval is determined to be 15 to 15 by the pulse interval detection process in step 52 in FIG.
Even if it is determined that the noise interval is not within 22 msec, 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. step
The process for restoring the power consumption shown in 59 is not performed, and the control system continues to be operated by the backup power supply means in a low power consumption state.

On the other hand, as shown in the conventional example in Fig. 6, when electromagnetic noise etc. is added to the input port IN1,
If this is misinterpreted as a power outage recovery signal and processing for power outage recovery is performed, the control system will shift to a high power consumption state and the charging power of the backup power source will be rapidly reduced before a normal power outage recovery can be performed. It will be consumed by

[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 prevents the return of normal power supply to noise. Since the input is clearly distinguished and detected, even when used in a noisy environment, it is possible to always respond to a power supply outage within a predetermined time, and after the normal power supply is restored, the power supply It has the advantage that it can be operated reliably in the setting state before stopping.

[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.
3 and 4 are flowcharts for explaining the operation, FIG. 5 is a timing chart showing signals etc. 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: Heat retention heater, 10: Control IC with built-in power return detection means, 18: Large capacitor constituting backup power supply means, 30: Synchronous signal generation circuit.

Claims (1)

[Scope of Claims] 1. In a rice cooker in which the control system is maintained in an operating state by backup power supply means in a low power consumption state when power supply from an AC power source is stopped, the control system is kept in an operating state by backup power supply means. A rice cooker characterized in that it has a power supply return detection means that detects the return of power supply from an AC power source, distinguishing it from noise input, at a certain time. 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 period, and when the counted value is equal to or greater than a predetermined number, the AC power supply is restarted. 2. The rice cooker according to claim 1, wherein the rice cooker detects the return of power supply from the source separately from noise input.