JP2022078416A - Cooker - Google Patents

Abstract

To detect a malfunction of a heater by a simple circuit configuration with no erroneous detection.SOLUTION: A cooker includes: heating means (heater 3) for heating a material to be heated; a main relay 2 connected to a front stage of a commercial power supply side of the heating means 3; a heater relay 4 connected to a rear stage of the commercial power supply side of the heating means 3; relay operation abnormality detection signal detection means 71 for receiving a relay operation abnormality detection signal from a relay operation abnormality detection circuit 5 branching from between the heating means 3 and the main relay 2, and from between the heating means and the heater relay 4; power synchronization signal detection means 73 for receiving a power synchronization signal from a power synchronization signal generation circuit branching from a front stage of a commercial power supply side of the main relay 2 and connected to the downstream side of a rectification circuit for rectifying voltage of commercial power supply; and relay drive signal output means 72 for outputting a relay drive signal for controlling operations of the main relay 2 and the heater relay 4.SELECTED DRAWING: Figure 1

Description

The present invention relates to a configuration and means for detecting a contact abnormality of a relay connected to a heater of a cooking cooker.

In a heating cooker, a relay is used to conduct the heater at an arbitrary timing, and ON / OFF is controlled by a relay drive circuit. However, the relay contact may be blown or welded, and the heater is particularly welded. Is always conductive and is in a heated state, so there is a risk of fire.

Patent Document 1 has a main relay for supplying power to the heater, a heater relay for turning the heater on and off, and a temperature detection unit for detecting the temperature in the cooking room, and only the main relay is turned on at the start of heating. Disclosed is a method of notifying an abnormality by determining that the heater relay is welded if the temperature in the cooking chamber is detected after a lapse of a predetermined time and the temperature rises above a certain level.

Patent Document 2, of the two relays connected to both ends of the heater, has a contact abnormality detection circuit at one terminal, has a current detection circuit that detects the current flowing through the heater, and has a contact abnormality detection circuit and a current detection circuit. A method of detecting one or both relay abnormalities from the consistency of the output of is described.

Japanese Unexamined Patent Publication No. 2009-258049 Japanese Unexamined Patent Publication No. 8-75176 Japanese Patent Application No. 2020-152503

In the heating cooker described in Patent Document 1, when the heater relay is normal, the heater does not conduct just by turning on the main relay, so that the cooker is not heated until a predetermined time elapses after the main relay is turned on, and cooking takes time. It takes. The cooking device described in Patent Document 2 has a current detection circuit for detecting the current flowing through the heater, and the detection is costly. The cooking device described in Patent Document 3 has a problem that there is a possibility of erroneous detection when the power supply voltage drops.

The present invention has been made to solve the above-mentioned problems, and the uniform state thereof includes a heating means for heating an object to be heated, a main relay connected to the front stage on the commercial power supply side of the heating means, and the above-mentioned. A relay operation abnormality detection signal branched from a heater relay connected to the rear stage on the commercial power supply side of the heating means and a relay operation abnormality detection circuit branched between the heating means and the main relay and between the heating means and the heater relay. Power supply synchronization that receives the power supply synchronization signal from the relay operation abnormality detection signal detection means that receives the The signal detection means and the relay drive signal output means for outputting a relay drive signal for controlling the operation of the main relay and the heater relay are provided, and the relay operation abnormality detection signal detection means has the power supply synchronization signal turned on. The relay operation is estimated from the relay drive signal immediately after the synchronization signal is turned off from the relay operation abnormality detection signal pattern detected by the relay operation abnormality detection signal detecting means immediately after the relay operation is turned off. The heating cooker was used to detect the malfunction of the main relay or the heater relay as compared with the pattern of the abnormality detection signal.

According to the present invention, it is possible to provide a cooking device that detects an abnormality of a relay in a short time and at a low cost without erroneous detection.

It is a circuit diagram which shows the circuit structure which concerns on 1st Embodiment of this invention. It is a figure which shows the power supply synchronization signal which concerns on 1st Embodiment of this invention. It is a figure which shows the relay operation abnormality detection signal which concerns on 1st Embodiment of this invention. It is a flowchart for detecting a relay operation abnormality which concerns on 1st Embodiment of this invention. It is a figure which shows the normal relay operation abnormality detection signal pattern when the main relay and the heater relay are turned off. It is a figure which shows the relay operation abnormality detection signal pattern when the main relay is not open state. It is a figure which shows the relay operation abnormality detection signal pattern when the main relay is not short-circuited. It is a figure which shows the relay operation abnormality detection signal pattern at the time of a main relay normal, a heater relay abnormality. It is a circuit diagram which shows the circuit structure which concerns on 2nd Embodiment of this invention. It is a figure which shows the relay operation abnormality detection signal pattern at the time of the main relay / heater relay normal. It is a figure which shows the relay operation abnormality detection signal pattern at the time of a main relay normal, a heater relay abnormality. It is a figure which shows the relay operation abnormality detection signal pattern when the main relay and the heater relay are normal when the power supply voltage drops. It is a figure which shows the relay operation abnormality detection signal pattern when the main relay is normal and the heater relay is abnormal when the power supply voltage drops. It is a circuit diagram which shows the circuit structure which concerns on 2nd Embodiment of this invention. It is a flowchart for detecting a relay operation abnormality which concerns on 2nd Embodiment of this invention.

Hereinafter, the first embodiment of the present invention will be described with reference to the drawings and the like. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various changes and modifications can be made by those skilled in the art within the scope of the technical idea disclosed in the present specification, and it is planned from the beginning that the configurations of the following examples are appropriately combined. Further, in all the drawings for explaining the present invention, those having the same function may be designated by the same reference numerals, and the repeated description thereof may be omitted.

FIG. 1 shows a form of a cooking device for carrying out the present invention. Of the heater 3 for heating the object to be heated, the commercial power supply 11 and both ends of the heater, the main relay 2 and its drive circuit connected in series in the front stage, and the heater relay 4 and its drive connected in series in the rear stage. The circuit, the relay operation abnormality detection circuit 5 connected between the main relay 2 and the heater 4 and between the heater 2 and the heater relay 4, the rectifying circuit 8 for rectifying the commercial power supply 1, and the rectifying circuit 8 are connected. It includes a power supply synchronization signal generation circuit 6 and a control unit 70 that detects each signal and controls each relay. The control unit 70 detects the relay operation abnormality detection signal detecting means 71 that detects the relay operation abnormality signal, the relay drive signal output means 72 that outputs the relay drive signals of the main relay 2 and the heater relay 4, and the power supply synchronization signal. It has a power supply synchronization signal detecting means 73.

The power supply synchronization signal obtained from the power supply synchronization signal generation circuit 6 will be described with reference to FIG. The power supply synchronization signal generation circuit 6 is connected to the commercial power supply 1 voltage after rectification after the commercial power supply 1 is rectified, and is connected to a voltage dividing resistor, a filter circuit for noise reduction, a pull-up resistor, and a transistor for signal switching. It is composed. Since the rectifier circuit 8 is connected to the front stage of the main relay 2, the input voltage changes depending on the operating state of the main relay 2.

When the main relay 2 is off (open state), in the case of a negative phase, the current path is cut off by the main relay 2, so that only the positive phase voltage of the commercial power supply 1 is applied to the rectifier circuit 8. .. When the voltage of the commercial power supply 1 after rectification is 0V, the transistor does not operate and is cut off, so that the pulled-up signal (High) is input to the power supply synchronization signal detecting means 73. When the voltage of the commercial power supply 1 after rectification is higher than 0V (strictly speaking, when the voltage obtained by dividing the voltage of the commercial power supply 1 after rectification by the voltage dividing resistor is equal to or higher than the transistor drive voltage), the transistor operates and the pull-up resistor and GND are connected. Therefore, 0V (Low) is input to the power supply synchronization signal detecting means 73.

When the main relay 2 is on (short-circuited state)), the negative phase side also conducts, so that both positive and negative phase voltages are applied to the rectifier circuit 8. Since the operating conditions of the transistor do not change, the voltage of the commercial power supply 1 after rectification becomes High near 0V (strictly speaking, when the voltage obtained by dividing the voltage of the commercial power supply 1 after rectification by the voltage dividing resistor is less than the transistor drive voltage). Signal is input to the power supply synchronization signal detecting means 73.

FIG. 3 shows the relay operation abnormality detection signal obtained from the relay operation abnormality detection circuit 5 according to the operation state of the main relay 2 and the heater relay 4. The relay operation abnormality detection circuit 5 is branched from between the main relay 2 and the heater 3 and between the heater 3 and the heater relay 4, and has a backflow prevention diode, a voltage dividing resistor, a filter circuit for noise reduction, and a pull-up resistor. , Consists of a transistor for signal switching.

When the main relay 2 and the heater relay 4 are off (open state), the voltage applied to the relay operation abnormality detection circuit 5 is 0V because it is cut off from the commercial power supply 1, and the transistor does not operate, so the relay operation abnormality detection signal. A pulled-up signal (High) is input to the detection means 71.

When the main relay 2 is on (short-circuited state) and the heater relay 4 is off (open state), the commercial power supply 1 is applied only from the terminal connected between the main relay 2 and the heater 3, but the heater relay 4 Is cut off in the off state, so that only the positive phase of the commercial power supply 1 is applied to the relay operation abnormality detection circuit 5. Since the circuit after application has the same configuration as the power supply synchronization signal circuit 6, the relay operation abnormality detection signal obtained at this time is Low when the commercial power supply 1 voltage is in the positive phase and High when the voltage is in the negative phase. A signal is obtained.

When the main relay 2 is off and the heater relay 4 is on, the commercial power supply 1 is not applied to the circuit in the subsequent stage because it is cut off by the main relay 2, and the relay operation abnormality detection signal is always due to the pull-up resistance. High signal is obtained.

When the main relay 2 and the heater relay 4 are on, the main relay 2, the heater 3, and the heater relay 4 are connected to the commercial power supply 1, so that both positive and negative phase voltages are applied to the relay operation abnormality detection circuit 5. Will be done. In this case as well, similarly to the power supply synchronization signal circuit, a relay operation abnormality detection signal that becomes High when the commercial power supply 1 is near 0V can be obtained. Next, an operation example for detecting an abnormality in the main relay will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart from outputting a control signal for turning off the main relay 2 and the heater relay 4 to detecting a malfunction of the main relay 2 or the heater relay 4. 5 (a)-(d) show the relay operation abnormality detection signal pattern and the power supply synchronization signal pattern obtained when the control signal is output according to the operating states of the main relay 2 and the heater relay 4. It is a thing.

First, the control unit 70 outputs a signal for turning off the main relay and the heater relay from the relay drive signal output means 72 (S101). After that, the moment when the power supply synchronization signal falls from High to Low is detected (S102), and immediately after that (strictly speaking, the time lapse considering the voltage dividing resistance tolerance, the transistor on-voltage tolerance, and the time constant of the filter circuit is taken into consideration. Later), the relay operation abnormality detection signal is acquired (S103). This is repeated a plurality of times (8 times in the first embodiment) and held as a relay operation abnormality detection signal pattern (S104). Among the relay operation abnormality detection signal patterns stored in the relay operation abnormality detection signal pattern storage means 74, the held relay operation abnormality detection signal pattern is a relay operation abnormality detection pattern in which the main relay is off and the heater relay is off. It is determined whether or not it matches "HHHHHHHH" (S105). If the main relay is normal, as shown in FIG. 5A, the acquired relay operation abnormality detection signal pattern is also "HHHHHHHH", which matches the stored relay operation abnormality detection signal pattern. When the main relay is not in the open state, that is, when the operation is malfunctioning in the welded state, the acquired relay operation abnormality detection signal pattern becomes "HLHLHLHL" or "LHLHLHLH" as shown in FIG. 5 (b). Since it does not match the stored pattern, it is possible to detect a malfunction in the welded state (S106).

When the normal operation of the main relay is confirmed, a signal for turning on the main relay is output from the relay drive signal output means 72 (S107). After that, similarly to the relay operation abnormality determination method when the main relay is off, the moment when the power supply synchronization signal falls from High to Low is detected (S108), and immediately after that, the relay operation abnormality detection signal is acquired (S109). This is repeated a plurality of times (8 times in the first embodiment) and held as a relay operation abnormality detection signal pattern (S110). Among the relay operation abnormality detection signal patterns stored in the relay operation abnormality detection signal pattern storage means 74, the held relay operation abnormality detection signal pattern is a relay operation abnormality detection pattern in which the main relay is on and the heater relay is off. It is determined whether or not it matches "HLHLHLHL" or "LHLHLHLH" (S111).

If the main relay is normal, the acquired relay operation abnormality detection signal pattern becomes "HLHLHLHL" or "LHLHLHLH" as shown in FIG. 5A, and matches the stored relay operation abnormality detection signal pattern. If the main relay is not in the short-circuited state, that is, if the operation is malfunctioning in the blown state, the acquired relay operation abnormality detection signal pattern is "HHHHHHHH" and is stored as shown in FIG. 5 (c). Since it does not match the pattern, it is possible to detect a malfunction in the blown state of the main relay (S112). Further, when the heater relay is malfunctioning in the welded state, the acquired relay operation abnormality detection signal pattern is "LLLLLLLL" as shown in FIG. 5 (d), and does not match the stored pattern. It is possible to detect a malfunction in the welded state of the heater relay (S113).

Next, an operation example for detecting a fusing abnormality of the heater relay 4 will be described with reference to FIGS. 4 and 6 and 7. FIG. 6 illustrates a flowchart from outputting a control signal for turning on both the main relay 2 and the heater relay 4 to detecting an abnormality (fusing) of the heater relay 4. FIG. 7 illustrates the patterns of the relay operation abnormality detection signal and the power supply synchronization signal obtained when the control signal is output according to the operating states of the main relay 2 and the heater relay 4.

Here, it is assumed that the main relay is operating normally. First, the control unit 70 outputs a signal for turning on the main relay and the heater relay from the relay drive signal output means 72 (S201). After that, the moment when the power supply synchronization signal falls from High to Low is detected (S202), and immediately after that, the relay operation abnormality detection signal is acquired (S203). This is repeated a plurality of times (8 times in the first embodiment) and held as a relay operation abnormality detection signal pattern (S204). Among the relay operation abnormality detection signal patterns stored in the relay operation abnormality detection signal pattern storage means 74, the held relay operation abnormality detection signal pattern is a relay operation abnormality detection pattern in which the main relay is turned on and the heater relay is turned on. It is determined whether or not it matches "LLLLLLLL" (S205).

If the heater relay is normal, the acquired relay operation abnormality detection signal pattern becomes "LLLLLLLL" as shown in FIG. 7A, and matches the stored relay operation abnormality detection signal pattern. If the heater relay is in a blown state and malfunctions, the acquired relay operation abnormality detection signal pattern becomes "HLHLHLHL" or "LHLHLHLH" as shown in FIG. 7 (d), and does not match the stored pattern. Therefore, it is possible to detect a malfunction in the blown state of the heater relay (S206).

As described above, the relay operation abnormality detection signal and the power supply synchronization signal change depending on the on / off of the transistor. A voltage obtained by dividing the voltage obtained by rectifying the power supply voltage with a voltage dividing resistor is applied to the base terminal of the transistor. When this voltage exceeds the on voltage of the transistor, the transistor turns on. Therefore, when the original power supply voltage changes, the timing at which the transistor turns on changes.

FIG. 8B illustrates the patterns of the relay operation abnormality detection signal and the power supply synchronization signal obtained when the power supply voltage becomes low according to the operating states of the main relay 2 and the heater relay 4. Comparing FIGS. 7 and 8 (b), when the power supply voltage becomes low, the low time of the power supply synchronization signal and the relay operation abnormality detection signal becomes shorter, but the same signal pattern as in FIG. 7 can be obtained. Since it is possible, even if the power supply voltage becomes low, it is possible to detect the malfunction of the heater relay in the same manner.

By determining the abnormality of the relay as described above, even if the power supply voltage becomes low, it is possible to detect the malfunction of the main relay in a short time and detect the malfunction of the heater relay while performing the heating operation. can.

Example 2 of the present invention will be described with reference to FIGS. 8 and 9. FIG. 8 shows a mode in which the heater 2 and the heater relay 4 are connected in parallel, unlike the first embodiment. The first heater 3a and the second heater 3b are branched in parallel from the rear stage of the main relay 2 when viewed from the commercial power source 1, and the first heater relay 4a and the second heater relay 4b are branched from the heaters 3a and 3b. Each is connected in series. A plurality of relay drive signal output means for outputting the drive signal of the heater relay are connected in parallel, and a relay operation abnormality detection circuit connected between each heater and the heater relay is provided.

FIG. 9 shows a flowchart for detecting a malfunction of the main relay 2 and the heater relay 4 taken when the circuit configuration as shown in FIG. 8 is adopted. Similar to the first embodiment, the relay operation abnormality signal pattern is acquired (S302) in the state where the off signal is output for all the relays, and if the acquired pattern is other than "HHHHHHHH", the main relay 2 is welded. It is possible to detect a malfunction of the state (S304). Next, the ON signal of the main relay 2 is output (S305), the relay operation abnormality signal pattern is acquired (S306), and if the acquired pattern is "HHHHHHHH", the main relay is in a blown state malfunction (S309). If it is "LLLLLLLL", it is possible to detect a malfunction (S308) in the welded state of the first heater relay 4a or the second heater relay 4b.

Next, the ON signal of the first heater relay 4a is output (S310), the relay operation abnormality signal pattern is acquired (S311), and if the acquired pattern is "HLHLHLHL" or "LHLHLHLH", the first heater relay It is possible to detect a malfunction in the fusing state of 4a (S313). Next, a signal for turning off the first heater relay 4a is output (S314), a relay operation abnormality signal pattern is acquired (S315), and if the acquired pattern is "LLLLLLLL", the welded state of the first heater relay 4a. (S317). If the same method is used, it is possible to detect a malfunction in the welded or fused state of the second heater relay 4b.

1: Commercial power supply 1
2: Main relay 3: Heater 3a: First heater 3b: Second heater 4: Heater relay 4a: First heater relay 4b: Second heater relay 5: Relay operation abnormality detection circuit 6: Power supply synchronization signal generation Circuit 8: Rectifier circuit 70: Control unit 71: Relay operation abnormality detection signal detection means 72: Relay drive signal output means 73: Power supply synchronization signal detection means

Claims (2)

A heating means for heating the object to be heated, a main relay connected to the front stage on the commercial power supply side of the heating means, and
A heater relay connected to the rear stage on the commercial power supply side of the heating means,
A relay operation abnormality detection signal detecting means that receives a relay operation abnormality detection signal from a relay operation abnormality detection circuit branched from between the heating means and the main relay and between the heating means and the heater relay.
A power supply synchronization signal detecting means that receives a power supply synchronization signal from a power supply synchronization signal generation circuit connected downstream of a rectifier circuit that branches from the front stage on the commercial power supply side of the main relay and rectifies the voltage of the commercial power supply.
A relay drive signal output means for outputting a relay drive signal that controls the operation of the main relay and the heater relay is provided.
The relay operation abnormality detection signal detecting means displays the relay operation abnormality detection signal pattern detected by the relay operation abnormality detection signal detecting means immediately after the power supply synchronization signal is turned from ON to OFF, and the synchronization signal is turned from ON to OFF. A heating cooker that detects a malfunction of the main relay or the heater relay by comparing with a pattern of the relay operation abnormality detection signal inferred from the relay drive signal immediately after becoming. In the cooking device according to claim 1,
The relay operation abnormality detection signal detecting means receives the relay operation abnormality detection signal immediately after the power supply synchronization signal is turned from ON to OFF when the main relay and the heater relay are turned off by the relay drive signal. A heating cooker that detects a malfunction of the main relay when the pattern does not match the pattern of the relay operation abnormality detection signal presumed when the main relay and the heater relay are OFF.

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