JP5195029B2 - Relay control device and cooking equipment - Google Patents

Description

  The present invention relates to a relay control device that controls a load such as a heater with a relay, and a cooking appliance including the relay control device.

  Conventionally, a power supply circuit for driving a relay when a load such as a heater is controlled by a relay outputs a voltage higher than the moving voltage of the relay when no current flows through the relay coil, and the current flows through the relay coil. When flowing, there is a method of configuring the relay voltage to be equal to or lower than the relay impression voltage and equal to or higher than the relay open voltage (holding voltage) (see, for example, Patent Document 1).

In Patent Document 1, a power supply circuit for driving a relay is configured by a constant voltage circuit including a rectifier diode, a resistor, a Zener diode, and a smoothing capacitor, and an output voltage of the power supply circuit is detected to be equal to or higher than a predetermined output voltage. Sometimes when the relay is turned on, the time from the connection of the AC power supply to the relay drive is shortened, and when the current flows through the relay coil, the output voltage of the power circuit is lowered to reduce the current flowing through the relay coil. , Relay coil heat generation is suppressed.
JP-A-8-266800

  However, in such a conventional configuration, in order to change the output voltage of the power supply circuit between when the current flows through the relay coil and when it does not flow, the smoothing connected to the output of the power supply circuit It was necessary to design the capacity of the capacitor or the capacity of the capacitor connected in parallel to both ends of the relay coil to an optimum value. However, due to the deterioration of the capacitor over time, the time constant between the capacitor and the coil is reduced, and there is a problem that the time during which the moving current of the relay flows (or the time during which the moving voltage is applied to the relay coil) is shortened.

  In addition, if it is attempted to secure the time for the moving current of the relay to flow for several years or more in consideration of the aging of the capacitor, it is necessary to increase the capacity of the capacitor, which increases the size of the capacitor and the size of the device. was there.

  In addition, when no current flows through the relay coil, the power supply voltage for driving the relay is increased, the applied voltage to the circuit components other than the relay is increased, and the circuit that excludes the relay is increased as the applied voltage is increased. There is a problem in that the current flowing through the component increases and the current does not flow through the relay coil, that is, the standby power without using the device increases.

  The present invention solves the above-described conventional problems, and the timing of switching the output voltage from a voltage higher than a moving voltage capable of supplying a moving current to a voltage higher than a holding voltage capable of supplying a holding current is determined by the capacitance of the capacitor and the resistance of the relay coil The first object is to enable the setting regardless of the influence of the value or the like and to ensure long-term guarantee.

  A second object of the present invention is to provide a cooking appliance that can use the relay for a long period of time and has a long product life.

In order to achieve the first object, the relay control device of the present invention conducts or cuts off a current path between a load and an AC power supply by a relay, converts the AC power supply to a DC power supply by a first DC power supply circuit, The output voltage of the first DC power supply circuit is converted to a voltage lower than the output voltage of the first DC power supply by the second DC power supply circuit, and the relay is turned on by the control means that receives power supply from the second DC power supply circuit, configured to control the cut-off, the first DC power supply circuit has a plurality of output voltages, the driving power of the relay is supplied from the first DC power supply circuit in response to a control signal of the control means, the first DC The power supply circuit is composed of a switching power supply that has a supply capability that does not drop even when the relay's moving current is supplied.When the control means conducts the relay, the output voltage of the first DC power supply circuit is set to the relay's moving current. Serving Set above can impressed voltage, the output voltage of the first DC power supply circuit is set more than the holding voltage that can be supplied holding current of the relay from the starting conduction of the relay after a predetermined period of time, when the relay is cut off, the The output voltage of one DC power supply circuit is set to a value lower than the moving voltage that can supply the moving current of the relay, and the output voltage of the first DC power supply circuit is set to be higher than the moving voltage before turning on the relay . Is.

As a result, the control means can switch the output voltage of the first DC power supply circuit that supplies current to the coil of the relay according to the conduction time of the relay. The timing of switching the output voltage to a voltage that is higher than the holding voltage that can supply current can be set regardless of the influence of the capacitance of the capacitor and the resistance of the relay coil that make up the first DC power supply circuit. It is not affected by the aging of the capacitor that is a component of the circuit, and the long-term guarantee of the relay control device can be made. Further, since the output voltage output to the second DC power supply circuit is lowered, the power consumption of the second DC power supply circuit is reduced, and the power when the relay control device is not operated, that is, the standby power can be reduced. it can.

  Moreover, in order to achieve the said 2nd objective, the cooking appliance of this invention is equipped with the above-mentioned relay control apparatus.

  Thereby, since a relay can be used over a long period of time, the cooking appliance with a long product life can be provided.

  In the relay control device of the present invention, the output voltage of the power supply circuit (first DC power supply circuit) that supplies current to the relay coil can be set by the control means. The output voltage of the first DC power supply circuit that supplies current to the current can be switched from a voltage that is higher than the moving voltage that can supply the moving current to a voltage that is higher than the holding voltage that can supply the holding current. It is not affected by the deterioration of parts over time, miniaturization of parts and long-term guarantee of relay control devices.

  Moreover, since the cooking appliance of this invention can use a relay over a long period of time, the cooking appliance with a long product life can be provided.

A relay control device according to a first aspect of the present invention includes an AC power supply, a load, a relay that conducts or cuts off a current path of the load and the AC power supply, and a first DC power supply circuit that converts the AC power supply into a DC power supply. A second DC power supply circuit that converts the output voltage of the first DC power supply circuit to a voltage lower than the output voltage of the first DC power supply circuit; and the power supply from the second DC power supply circuit Control means for controlling conduction and interruption of the relay, wherein the first DC power supply circuit has a plurality of output voltages, and the driving power of the relay is in accordance with the control signal of the control means. The first DC power supply circuit is supplied from a power supply circuit, and the first DC power supply circuit is configured by a switching power supply having a supply capability that does not drop even when the moving current of the relay is supplied, and when the control means conducts the relay, first The output voltage of the DC power supply circuit is set to be equal to or higher than the moving voltage capable of supplying the moving current of the relay, and the output voltage of the first DC power supply circuit is supplied with the holding current of the relay after a predetermined time has elapsed after the relay starts to conduct. It is constructed so that it can be set to a holding voltage or higher, and the control means can switch the output voltage of the first DC power supply circuit that supplies current to the coil of the relay according to the relay conduction time. The timing of switching the output voltage from a voltage that is higher than the moving voltage that can supply current to a voltage that is higher than the holding voltage that can supply the holding current is affected by the capacitance of the capacitors that make up the first DC power supply circuit and the resistance value of the relay coil. Can be set regardless of the aging of the capacitor, which is a component of the first DC power supply circuit. It is proof. Also, when the relay conduction time is long, the output voltage of the first DC power supply circuit can be made smaller than the moving voltage of the relay and larger than the holding voltage, so the output voltage to the second DC power supply circuit is also The power consumption of the relay control device can be reduced.

Further , the control means sets the output voltage of the first DC power supply circuit to a value lower than the moving voltage capable of supplying the moving current of the relay when the relay is cut off, and before turning on the relay, The output voltage of the DC power supply circuit is set to be equal to or higher than the moving voltage, and the output voltage output to the second DC power supply circuit is low, so the power consumption of the second DC power supply circuit is reduced, The power when the relay control device is not moving, that is, standby power can be reduced.

According to a second aspect of the present invention, in the first aspect of the invention, when the control means shuts off the relay, the control means outputs the output voltage of the first DC power supply circuit from the holding voltage that can supply the holding current of the relay. The value is set to a low value, and when the relay is shut off, no current is supplied to the relay coil even if the control means outputs a control signal that turns on the relay due to the influence of external noise, etc. Since the relay contact is not connected, it is possible to provide a safe relay control device in which the relay contact is accidentally connected and the load is not conducted when the relay control device is not operated. Moreover, since the voltage output to the second DC power supply circuit is lowered, the power consumption of the second DC power supply circuit is reduced, and the standby power of the relay control device can be reduced.

According to a third aspect of the present invention, there is provided a relay control device according to the first aspect, further comprising voltage detection means for detecting the output voltage of the first DC power supply circuit, and the control means is configured to detect the output voltage of the first DC power supply circuit by the voltage detection means when the relay is turned on. When the detected voltage is less than or equal to the moving voltage of the relay, the relay is controlled so as not to start conduction, and it is possible to prevent a moving current from being supplied when the relay is turned on. It is possible to prevent the contact of the relay from being defective due to the conduction of the relay with a current smaller than the current.

According to a fourth aspect of the present invention, there is provided a relay control device according to the first aspect, wherein the zero voltage synchronization signal generating means for generating a signal synchronized with the zero voltage of the AC power supply, and the time from the output of the zero voltage synchronization signal generating means. Timer means for measuring, and timing setting means for setting a timing time from the output signal of the zero voltage synchronization signal generating means until the relay is turned on or off, and the control means is a timing time set by the timing setting means And the timing setting means changes the timing time so that the positive and negative phases of the AC power supply alternate, and the timing setting means changes the current of the current flowing through the contact of the relay. The average value is almost zero, so that the metal transition of the relay contact can be suppressed and the durability of the relay contact can be improved.

According to a fifth aspect of the present invention, there is provided a relay control device according to the first aspect, comprising: a plurality of loads; and a plurality of relays for conducting or blocking the current paths of the plurality of loads and the AC power source. When one of the plurality of relays is turned on, the output voltage of the first DC power supply circuit is set to the moving current of the relay regardless of whether the other relays are turned on or off. It is set so that it can be supplied more than the impressed voltage, and then the output voltage of the first DC power supply circuit is set to be higher than the holding voltage that can supply the holding current of the relay after a predetermined time has elapsed. There is no need to add a circuit for optimizing the current supplied to the coil, and the number of circuit components can be reduced. When the relay is turned on, first, the output voltage of the first DC power supply circuit is switched to a voltage higher than the moving voltage that can supply the moving current of the relay. Since the output voltage of the circuit is switched to the holding voltage that can supply the holding current of the relay, the relay can be operated reliably within the guaranteed operation range of the relay regardless of the number of relays, and the reliability of the relay control device is improved. be able to.

According to a sixth aspect of the present invention, there is provided a relay control device according to the fifth aspect , comprising two or more relays having different moving currents, and the control means has the largest moving current among the different moving currents when the relay is conducted. The output voltage of the first DC power supply circuit is set so that the impression voltage can be supplied, and the set value of the output voltage of the first DC power supply circuit can be reduced, and the relay control device The number of components can be reduced, and relay control can be simplified. In addition, since the largest moving current among the moving currents of multiple relays can be passed, even if relays with different moving currents are conducted at the same time, the moving current of the relays is not sufficient, and the relay contacts are unstable. Therefore, it is possible to suppress relay failures such as welding of relay contacts.

According to a seventh aspect of the present invention, there is provided a relay control device according to the sixth aspect , comprising two or more relays having different holding currents, wherein the control means has the largest of the different moving currents when the relays are conducted. The output voltage of the first DC power supply circuit is set so as to be a moving voltage that can supply the current, and after a predetermined time has elapsed after the relay is turned on, the holding voltage that can supply the largest holding current among the different holding currents is set. In this way, the output voltage of the first DC power supply circuit is set so that the set value of the output voltage of the first DC power supply circuit can be reduced and the number of components of the relay control device is reduced. And relay control can be simplified. In addition, since the maximum holding current among the holding currents of the plurality of relays can be passed, even if relays with different holding currents are turned on at the same time, the relay holding current is not sufficient, and the relay contacts must be connected. It can be prevented that the load cannot be held and the load cannot be conducted. In addition, the relay contact cannot be maintained due to insufficient holding current of the relay. As a result, the relay contacts are separated, an arc is generated between the relay contacts, and the relay contacts are welded by this arc. Can be suppressed.

According to an eighth aspect of the present invention, there is provided a relay control device according to the first aspect, further comprising temperature detection means for detecting a temperature in the vicinity of the relay, and the control means is configured to control the first DC power supply circuit according to the output of the temperature detection means. The output voltage is changed. Even if the resistance value of the relay coil changes depending on the ambient temperature, the change in the ambient temperature is detected and the output voltage of the first DC power supply circuit is changed. The relay's moving current and holding current can be reliably supplied, and the relay contact can be prevented from being lost, and the relay contact cannot be maintained and the contact is released, preventing the load from conducting. Can be prevented.

A cooking appliance of the ninth invention is provided with the relay control device according to any one of the first to eighth inventions, and since the relay can be used for a long period of time, a cooking appliance having a long product life can be provided. . In addition, since cooking equipment and other equipment are heated, the ambient temperature of the relay controller increases even during normal use, so it can be assumed that the aging of the electrolytic capacitor is faster than that of AV equipment, but the output of the first DC power supply circuit Since this output voltage can be switched by setting the voltage using the control means, it is not necessary to set the capacity of the electrolytic capacitor while taking into account the period during which the relay's moving current flows and the power consumption of the device. It can be set taking into account only deterioration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a partially block circuit diagram of the relay control device according to the first embodiment of the present invention, and FIG. 2 shows a sectional view of a cooking appliance equipped with the relay control device of the present embodiment. is there. In FIG. 2, the electrical connection state is omitted.

  As shown in FIG. 1, the AC power source 1 is a commercial power source of 60 Hz 100 V or 50 Hz 100 V that is generally used in various parts of Japan. The heater 2 constitutes a load, and is composed of a tubular miraclon heater using a nichrome wire, and generates near infrared rays. This heater becomes about 400 W when 100 V is applied. In this embodiment, a heater using a nichrome wire is used, but a halogen heater may be used, or an argon heater may be used. A relay contact (relay) 3 is connected in series with the heater 2, and the current path between the heater 2 and the AC power supply 1 is made conductive and interrupted by turning on and off the relay contact 3.

  The first DC power supply circuit 4 converts the AC power supply 1 into a DC power supply. The half-wave rectifying / smoothing circuit 7 composed of a diode 5 and a capacitor 6 receives power from the half-wave rectifying / smoothing circuit 7 and is about 12V. And a switching power supply 8 that outputs a direct current voltage. The half-wave rectifying / smoothing circuit 7 uses the diode 5 and the capacitor 6 to half-wave rectify and smooth the AC power supply 1 and convert it to a DC voltage of about 141V. However, this is an example, and the AC power supply 1 may be full-wave rectified and smoothed using a diode bridge.

  Although not shown, the switching power supply 8 includes a power semiconductor element control circuit 9 including a power semiconductor element such as a MOSFET, and a control circuit for controlling on / off of the power semiconductor within a range of a predetermined current value, a coil 10, and a smoothing circuit. In order to feedback control the power semiconductor built-in control circuit 9 so that the voltage of the capacitor 11 and the voltage of the capacitor 11 become a predetermined set value, the output voltage detection circuit 12 is configured.

  The power semiconductor built-in circuit 9 charges the capacitor 12 via the coil 11 by performing on / off control of the built-in MOSFET within a predetermined current value range.

  Although not shown, the output voltage detection circuit 12 is composed of a photocoupler, a Zener diode of about 12 V, and a Zener diode of about 7 V, and the output voltage for feedback control is switched by switching the two Zener diodes.

  For example, when setting an output voltage of about 12 V, a photocoupler and a Zener diode are connected in series. When the voltage of the capacitor 11 exceeds 12V, the Zener diode for 12V is energized, the photocoupler is turned on, and the output voltage exceeding 12V is transmitted to the control circuit 9 with built-in power semiconductor. When the power semiconductor built-in control circuit 9 receives this signal, it turns off the switching operation of the built-in MOSFET. When the power supply to the capacitor 11 is stopped, the voltage drops and becomes lower than 12V, the 12V Zener diode is not energized, the photocoupler is turned off, and the output voltage to the power semiconductor built-in control circuit 9 is lower than 12V. Send. When the power semiconductor built-in control circuit 9 receives this signal, it starts the switching operation of the built-in MOSFET and charges the capacitor 11 via the coil 10.

  When the output voltage is set to 7V, the same operation can be performed by connecting a photocoupler and a 7V Zener diode in series. The output voltage detection circuit 12 of the present embodiment is different from the voltage detection means shown in claim 4. This voltage detection means will be described later.

  That is, in the present embodiment, the switching power supply 8 steps down the output voltage of about 141 V from the half-wave rectifying and smoothing circuit 7 to a DC voltage of about 12 V.

  The relay coil (relay) 13 has an output terminal of the first DC power supply circuit 4 connected to one terminal. In the present embodiment, the voltage rating of the relay coil 13 is a DC voltage of 12V. Moreover, the DC voltage (moving voltage) through which a moving current can flow is 10V, and the DC voltage (holding voltage) through which a holding current can flow is 5V.

  Although not shown, the second DC power supply circuit 14 is constituted by an emitter follower circuit using an NPN transistor and a Zener diode, and the output voltage of the switching power supply 8, that is, the output voltage of the first DC power supply circuit 4 is about 12V. Is converted to a voltage of about 5 V, which is lower than the output voltage of the first DC power supply circuit 4.

  The control means 15 includes a microcomputer 16, a drive circuit 17 that energizes the relay coil 13, an output voltage setting means 18 that sets the output voltage of the first DC power supply circuit 4, and the like. The control means 15 operates by being supplied with a DC voltage of about 5 V from the second DC power supply circuit 14. The microcomputer 16 outputs a high or low signal for energizing or interrupting the relay coil 13 to the drive circuit 17.

  The microcomputer 16 of the relay control device of the present embodiment outputs high or low to the output voltage setting means 18 and sets the detection voltage set value of the output voltage detection circuit 12 constituting the first DC power supply circuit 4. Switch. In the present embodiment, the microcomputer 13 outputs a low signal to the output voltage setting means 18 when setting the output voltage of the first DC power supply circuit 4 to about 12 V, and the output voltage of the first DC power supply circuit 4 is set. When the voltage is set to about 7 V, a high signal is output to the output voltage setting means 18.

  In the relay control device of the present embodiment, the time from the start of energization of the relay coil 13 is measured using a timer built in the microcomputer 16, and the output signal to the output voltage setting means 18 is switched after a predetermined time has elapsed. ing.

  The drive circuit 17 is composed of a transistor and the like. The transistor is turned on, and the output voltage 12V of the switching power supply 8 is supplied to the relay coil 13 so that a current flows in the relay coil 13 and the electromagnetic force generated in the coil relays. The contact 3 is driven.

  In general, when a rated voltage is applied to the relay coil 13, the relay can pass a current greater than the moving current. Therefore, if a relay whose rated voltage is 12 V is used, the relay contact 3 can be reliably connected.

  The moving current indicates the current value of the relay coil 13 that can be reliably connected by moving the relay contact 3, indicates the specification of the relay, and is a commonly used term.

  The output voltage setting means 18 is composed of a transistor or the like, and switches the set value of the detection voltage of the output voltage detection circuit 12 by turning on and off the transistor. In the relay control device of the present embodiment, when the transistor constituting the output voltage setting means 18 is turned on, the detection voltage of the output voltage detection circuit 12 is 7V, and when the transistor is turned off, the output voltage detection circuit 12 The detection voltage is 12V.

  Next, as shown in FIG. 2, the cooking appliance main body 21 is configured by forming a metal plate whose surface is plated in a box shape. The heating chamber 22 is formed by forming an aluminum plate into a box shape that is open in only one direction. Inside the heating chamber 22, heaters (Miraclon heaters) 2 are arranged on the top surface side and the bottom surface side. The two heaters are electrically connected in series.

  The door 23 is made of glass and a metal plate so that the state of the cooked food inside the heating chamber 22 can be visually observed. The handle 24 is made of resin, and the heater 2 is heated so that the user can grasp and open the door 23 even if the temperature of the door 23 rises.

  The control board 25 is mounted with the relay control device shown in FIG. 1, and controls the heater 2 by mounting a circuit other than the heater 2 in the main circuit configuration of the relay control device shown in FIG. In addition, a thermistor for detecting the temperature inside the heating chamber 22, a switch such as a tact switch, an LED, and the like are mounted, and a predetermined sequence as a cooking appliance is operated by a user pressing it.

  The operation panel 26 displays the meanings of the switches arranged on the control board 25 so that the user can set a desired menu and time with the switches. The meaning of the LEDs arranged on the control board 25 is displayed so that the user can recognize the remaining time and the current state.

  Although the grill net 27 is made of metal and is not shown in the figure, hooks are provided at the four corners of the grill net 27, and the grill net 27 is hooked on the hooks so that it can be placed at a predetermined position. Yes. The legs 28 are made of resin and arranged at the four corners of the cooking appliance body 21.

  In the above configuration, the operation and action of a cooking appliance equipped with the relay control device of the present embodiment will be described with reference to FIG. FIG. 3 is a timing chart showing operation waveforms of the respective parts of the relay control device shown in FIG. (A) shows the on / off state of the drive circuit 16, (b) shows the current waveform of the heater 2 and the relay contact 3, (c) shows the output voltage waveform of the first DC power supply circuit 4, (d) Shows the on / off state of the output voltage setting means 17, and (e) shows the voltage waveform of the AC power supply 1.

  First, a user puts food such as bread and rice cake on the grill 27 in the heating chamber 22 of FIG. At this time, the relay control device of FIG. 1 is already connected to the AC power source 1. The microcomputer 16 constituting the control means 15 outputs a high signal to the output voltage setting means 18. The transistors constituting the output voltage setting means 18 are turned on in response to this high signal. When this transistor is on, the set value of the detection voltage of the output voltage detection circuit 12 is 7V, and the output voltage of the first DC power supply circuit 4 is controlled to be 7V.

  When a desired switch is pressed according to the display on the operation panel 26 in the above state, the switch on the control board 25 is pressed via the operation panel 26, and heating corresponding to the switch is started.

  For example, when a switch on the operation panel 26 is pressed, the microcomputer 16 constituting the control means 15 outputs a low signal to the output voltage setting means 18 at time t0 in FIG. When the transistor constituting the output voltage setting means 18 is turned off in response to the low signal, the set value of the detection voltage of the output voltage detection circuit 12 constituting the first DC power supply circuit 4 becomes 12V, and the output voltage becomes 12V. Thus, the first DC power supply circuit 4 is controlled.

  The time from the 7V output voltage to the 12V output voltage is determined by the output current supply capability of the first DC power supply circuit 4. In this embodiment, it takes about 30 ms for the output voltage to change from 7V to 12V.

  At time t1, 40 ms has passed since the transistor of the output voltage setting means 18 was turned off. At time t1, the microcomputer 16 constituting the control means 15 outputs a high signal to the drive circuit 17. At the same time, the microcomputer 16 starts time measurement using a built-in timer.

  When the transistor constituting the drive circuit 17 is turned on, the relay coil 13 is energized. At this time, the current supply of the relay coil 13 is supplied from the first DC power supply circuit 4. Since the first DC power supply circuit 4 is controlled so that the output voltage becomes 12V, the voltage does not drop even if a current flows through the relay coil 13.

  When the relay coil 13 is energized, the relay contact 3 is driven by the electromagnetic force of the coil. Since the relay contact 3 moves and connects and opens the contact, it takes time until the relay contact 3 is connected and the heater 2 becomes conductive. In the present embodiment, at time t2 after about 7 ms, the contacts of the relays are connected, and the current path of the heater 2 becomes conductive.

  At time t3, 170 ms has elapsed since time t1. The microcomputer 16 measures this elapsed time with a built-in timer, and outputs a high signal to the output voltage setting means 18 when measuring that 170 ms has elapsed.

  When the transistor constituting the output voltage setting means 18 is turned on in response to this high signal, the detection voltage set value of the output voltage detection circuit 12 constituting the first DC power supply circuit 4 becomes 7V, and the output voltage becomes 7V. Thus, the first DC power supply circuit 4 is controlled.

  The power semiconductor built-in control circuit 9 does not perform the switching operation until the output voltage of the first DC power supply circuit 4 decreases from 12V to 7V. That is, the time from the 12V output voltage to the 7V output voltage is determined by the capacitance of the capacitor 11 and the resistance value of the relay coil 13 constituting the first DC power supply circuit 4. In this embodiment, it takes about 25 ms for the output voltage to change from 12V to 7V. In the present embodiment, since the DC voltage that allows the holding current of the relay coil 13 to flow is 5V, if the output voltage of the first DC power supply circuit 4 is set to 7V, a current that is higher than the holding current can be supplied. . At the same time, since the output voltage to the second DC power supply circuit 14 becomes 7V, the loss of the second DC power supply circuit 14 can be suppressed, and the power consumption of the relay control device excluding the power of the load (heater 2) Can be reduced.

  As described above, in the relay control device according to the present embodiment, when the relay is energized, the control unit 15 causes the output voltage of the first DC power supply circuit 4 to be higher than the moving voltage that can supply the moving current of the relay. Since the output voltage of the first DC power supply circuit 4 is set to be higher than the holding voltage that can supply the holding current of the relay after a lapse of a predetermined time from the start of relay conduction, the control means 4 sets the relay conduction time to the relay conduction time. Accordingly, the output voltage of the first DC power supply circuit 4 that supplies current to the relay coil 13 can be switched. Therefore, even if the capacity of the capacitor 11 constituting the first DC power supply circuit 4 is increased, the output voltage can be ensured. The power supply voltage can be switched at a predetermined timing, and the current consumption of the relay coil 13 and the loss of the second DC power supply circuit 14 that supplies power to the control means 15 can be suppressed.Further, in order to reduce the current consumption of the relay coil 13, a current limiting resistor may be connected in series to the relay coil 13, but this need not be required. Furthermore, when this current limiting resistor is connected in series, a capacitor may be connected in parallel to the relay coil in order to secure a current when the relay coil is activated, but this capacitor is also unnecessary.

  Further, in the relay control device of the present embodiment, as shown in FIG. 3, in the state before the relay is operated, the output voltage of the first DC power supply circuit 4 is lower than the moving voltage and higher than the holding voltage. 7V. By setting the voltage to 7V, the loss of the second DC power supply circuit 14 is reduced as compared with the case of 12V, and the power consumption can be reduced. So-called standby power can be reduced.

Moreover, in the cooking appliance of this Embodiment, since the above-mentioned relay control apparatus was provided, since a relay can be used over a long period of time, a cooking appliance with a long product life can be provided. In addition, since cooking equipment and the like are heated, the ambient temperature of the relay control device becomes high even during normal use, so it can be assumed that the aging of the electrolytic capacitor is faster than that of AV equipment and the like. Since the output voltage can be switched by setting the output voltage by the control means 15, it is not necessary to set the capacity of the electrolytic capacitor in consideration of the period during which the moving current of the relay flows and the power consumption of the device. It can be set taking into account only aged deterioration of

(Embodiment 2)
FIG. 4 shows a partially blocked circuit diagram of the relay control device according to the second embodiment of the present invention, and FIG. 5 is a cross-sectional view of a rice cooker as a cooking appliance equipped with the relay control device of the present embodiment. Is shown. In FIG. 5, lead wires for electrical connection and screws for fixing components are omitted for the sake of brevity.

  As shown in FIG. 4, the first heater 41 constitutes a load and is constituted by a sheathed heater. Generally, a sheathed heater has a configuration in which a heating element such as a nichrome wire is enclosed while an electric insulator is filled in a metal pipe. In the present embodiment, this sheathed heater is made of aluminum and is generally called a cast heater. This cast heater becomes about 400 W when 100 V is applied. The second heater 42 constitutes a load and is constituted by a sheathed heater. This sheathed heater becomes about 70 W when 100 V is applied.

  The first relay contact 43 is connected in series with the first heater 41, and turns on and off the first relay contact 43, thereby conducting and blocking the current path between the first heater 41 and the AC power supply 1. The second relay contact 44 is connected in series with the second heater 42, and turns on and off the second relay contact 44, thereby conducting and blocking the current path between the second heater 42 and the AC power supply 1.

  The first DC power supply circuit 45 includes a half-wave rectifying / smoothing circuit 7 composed of a diode 5 and a capacitor 6, and a switching power supply 46 that receives a power supply from the half-wave rectifying / smoothing circuit 7 and outputs a DC voltage of about 12V. doing.

  Although not shown, the switching power supply 46 includes a power semiconductor built-in control circuit 9 including a power semiconductor element such as a MOSFET and a control circuit that controls the power semiconductor within a predetermined current value range, a coil 10, and a smoothing circuit. In order to feedback control the power semiconductor built-in control circuit 9 so that the voltage of the capacitor 11 and the voltage of the capacitor 11 become a predetermined set value, the output voltage detection circuit 47 is configured.

  The power semiconductor built-in circuit 9 charges the capacitor 12 via the coil 11 by performing on / off control of the built-in MOSFET within a predetermined current value range. Although not shown, the output voltage detection circuit 47 is composed of a photocoupler, a Zener diode of about 12 V, a Zener diode of about 7 V, and a Zener diode of about 4 V, and feedback control is performed by switching these three Zener diodes. The output voltage is switched.

  For example, when setting an output voltage of about 12 V, a photocoupler and a Zener diode are connected in series. When the voltage of the capacitor 11 exceeds 12V, the Zener diode for 12V is energized, the photocoupler is turned on, and the power semiconductor built-in control circuit 9 is notified that the output voltage has exceeded 12V. When the power semiconductor built-in control circuit 9 receives this signal, it turns off the switching operation of the built-in MOSFET. When the power supply to the capacitor 11 is stopped, the voltage drops and becomes lower than 12V, the 12V Zener diode is not energized, the photocoupler is turned off, and the output voltage to the power semiconductor built-in control circuit 9 is lower than 12V. Send. When the power semiconductor built-in control circuit 9 receives this signal, it starts a switching operation of the built-in MOSFET and charges the capacitor 11 via the coil 10.

  When the output voltage is set to 7V, the same operation can be performed by connecting a photocoupler and a 7V Zener diode in series. When an output voltage of 4V is set, the same operation can be performed by connecting a photocoupler and a 4V Zener diode in series. The output voltage detection circuit 47 of the present embodiment is different from the voltage detection means shown in claim 4. This voltage detection means will be described later.

  That is, in this embodiment, the switching power supply 46 steps down the output voltage of about 141 V of the half-wave rectifying and smoothing circuit 7 to a DC voltage of about 12 V.

  The first relay coil 48 is connected to the output terminal of the first DC power supply circuit 45 at one terminal. In the present embodiment, the voltage rating of the first relay coil 48 is a DC voltage of 12V. Moreover, the direct-current voltage (stimulating voltage) which can flow a moving current is 10V. The DC voltage (holding voltage) through which a holding current can flow is 5V.

  The second relay coil 49 connects the output terminal of the first DC power supply circuit 45 to one terminal. In the present embodiment, the voltage rating of the second relay coil 49 is a DC voltage of 12V. Moreover, the direct-current voltage (moving voltage) which can flow a moving current is 11V. The DC voltage (holding voltage) through which a holding current can flow is 6V.

  The control means 50 includes an output from the microcomputer 51, a first drive circuit 52 that energizes the first relay coil 48, a second drive circuit 53 that energizes the second relay coil 49, and the first DC power supply circuit 45. The output voltage setting means 54 for setting the voltage is used. The control means 50 operates by being supplied with a DC voltage of about 5 V from the second DC power supply circuit 14.

  The microcomputer 51 outputs a high or low signal for energizing or interrupting the first relay coil 48 and the second relay coil 49 to the first drive circuit 52 and the second drive circuit 53. Further, the microcomputer 51 outputs a signal to the output voltage setting means 54 to switch the setting value of the detection voltage of the output voltage detection circuit 47 constituting the first DC power supply circuit 45.

  The first drive circuit 52 and the second drive circuit 53 are composed of transistors and the like, turn on the transistors, and supply the output voltage 12V of the switching power supply 46 to the first relay coil 48 or the second relay coil 49. Thus, a current is passed through the first relay coil 48 or the second relay coil 49, and the first relay contact 43 or the second relay contact 44 is driven by the electromagnetic force generated in the coil.

  The output voltage setting means 54 includes two transistors 55 and 56. The set value of the detection voltage of the output voltage detection circuit 47 is switched by the combination of the on and off of the two transistors 55 and 56. In the relay control device of the present embodiment, when the transistors 55 and 56 are both off, the set value of the detection voltage of the output voltage detection circuit 47 is 12V. When only the transistor 55 is on, the set value of the detection voltage of the output voltage detection circuit 47 is 7V. When only the transistor 56 is on, the set value of the detection voltage of the output voltage detection circuit 47 is 4V.

The zero voltage synchronization signal generating means 57 generates a signal synchronized with the zero voltage of the AC power supply 1 and is divided by the resistance voltage dividing circuit 58 formed by connecting two resistors in series and the resistance voltage dividing circuit 58. The transistor 59 is inputted to the base terminal to turn on and off, and one terminal is connected to the collector terminal of the transistor 59, and the other terminal is constituted by the resistor 60 connected to the output terminal of the second DC power supply circuit 14. ing. With the above configuration, when the voltage of the AC power supply 1 becomes close to zero voltage, the zero voltage synchronization signal generating means 57 switches from a high signal to a low signal or from a low signal to a high signal. In the relay control device of the present embodiment, the microcomputer 51 detects the switching of the high signal from the low signal of the zero voltage synchronization signal generating means 57, and measures the time by the timer means 61 constituted by the timer of the microcomputer 57. Begin to.

  The timing setting means 62 sets the timing time from the output signal of the zero voltage synchronization signal generating means 57 until the relay is turned on or off, and sequentially sets a plurality of timing times stored in the ROM of the microcomputer 51 in order. It will be switched to. In the relay control device of the present embodiment, this timing time is set to Ts1, Ts2, Ts3, and Ts4. In the present embodiment, Ts1, Ts2, Ts3, and Ts4 are set to have phases shifted by 90 degrees for each power supply frequency of the AC power supply 1. That is, when the power supply frequency of the AC power supply 1 is 50 Hz, Ts1 = 0 ms, Ts2 = 5 ms, Ts3 = 10 ms, and Ts4 = 15 ms. The timing setting means 62 changes the timing time from Ts1 to Ts4 so that the voltage phase of the AC power supply 1 is switched alternately.

  In the relay control device of the present embodiment, the time from the start of energization of the first relay coil 48 or the second relay coil 49 using a timer built in the microcomputer 51 provided separately from the timer means 61. The output signal to the output voltage setting means 18 is switched after a predetermined time has elapsed.

  Next, as shown in FIG. 5, the rice cooker body 71 has a lid 72 that can be opened and closed so as to cover the upper surface thereof. The rice cooker body 71 and the lid 72 are mechanically connected by a hinge shaft 73 made of stainless steel, and the lid 72 is opened and closed with the hinge shaft 73 as a rotation axis. The storage part 74 of the rice cooker main body 71 arranges the first heater 41 at the bottom. The first heater 41 is an aluminum cast heater as described with reference to FIG.

  The pan 75 is made of a metal such as aluminum. The pan 75 has a fluorine coating on its surface. The pan 75 has a flange protruding outward at the upper end opening. The pan 75 is detachably stored in the storage portion 74 by being placed in contact with the upper surface of the first heater 41. The user cooks by putting a heated object such as rice or water in the pan 75.

  The lid heating plate 76 is made of a metal such as stainless steel, and is detachably installed on the lid 72 via a rubber packing 77. A hole for allowing steam to escape to the outside is provided in a substantially central portion of the lid heating plate 76. A heat sink 78 made of aluminum is incorporated on the surface of the cover 72 that opposes the cover heating plate 76, and the second heater 42 is attached to the heat dissipation plate 78 in contact with an aluminum tape, although not shown. A steam port 79 is detachably attached to a substantially central portion of the lid 72, and steam generated in the pan 75 is discharged to the outside through the hole of the lid heating plate 76 and the steam port 79. .

  The first circuit board 80 includes a switch, an LCD, a microcomputer 51, and the like. The operation panel 81 is fitted in the rice cooker main body 71, and characters indicating the meaning of each switch are printed. When the user presses the portion, the switch mounted on the first circuit board 80 is pressed.

  Although not shown, the second circuit board 82 includes the second relay 44, the first DC power supply circuit 45, the second DC power supply circuit 14 and the like in addition to the first relay 43.

  The wind-up type power cord storage portion 83 is electrically connected to the second circuit board 82 via a lead wire. The power cord storage portion 83 can wind up the power cord using a stopper and a spring.

  The temperature detection means 84 is composed of a thermistor and is arranged at the approximate center of the bottom of the pan 75. Since the resistance value of the thermistor changes with temperature, a voltage dividing circuit is configured with this thermistor and a resistor having a predetermined resistance value, and the resistance value of the thermistor is analogized by supplying a predetermined voltage to both ends of the voltage dividing circuit. Can be converted to voltage. The microcomputer 51 shown in FIG. 4 estimates the temperature from this analog voltage using a built-in AD converter.

  Although not shown, the first circuit board 80 and the second circuit board 82 are electrically connected by lead wires, and the microcomputer 51, the first drive circuit 52, and the second drive circuit 53 allow the first circuit board 80 and the second circuit board 82 to be electrically connected. The first relay coil 48 and the second relay coil 49 are energized and controlled, the first relay contact 43 and the second relay contact 44 are connected, and the first heater 41 and the second heater 42 are electrically connected. The heater 41 and the second heater 42 generate heat, and the pan 75 and the lid heating plate 76 are heated by this heat generation.

  Thus, the rice cooker of this Embodiment heats the pan 75 with the heat_generation | fever of the 1st heater 41, and cooks the cooking thing in the pan 75 by heating. Here, the cooked product is rice before cooking rice, water, cooked rice, or the like.

  In the above configuration, the operation and action of the rice cooker equipped with the relay control device of the present embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 shows a part (first half) of a time chart showing operation waveforms of each part of the relay control device shown in FIG. (A) shows the on / off state of the first drive circuit 48, (b) shows the current waveforms of the first heater 41 and the first relay contact 43, and (c) shows the on / off state of the second drive circuit 49. (D) shows the current waveform of the second heater 42 and the second relay contact 44, (e) shows the output voltage waveform of the first DC power supply circuit 45, and (f) shows the output voltage. The on / off state of the transistor 55 constituting the setting means 54 is shown, (g) shows the on / off state of the transistor 56 constituting the output setting means 54, (h) shows the voltage waveform of the AC power supply 1, and (i) The output signal of the zero voltage synchronizing signal generating means 57 is shown. FIG. 7 shows the continuation (second half) of the time chart of FIG. 6, and (a) to (i) are the same as FIG. 6.

  First, the user puts rice and water into the pan 75 of FIG. At this time, the relay control device of FIG. 4 is already connected to the AC power source 1. The microcomputer 51 constituting the control means 50 outputs a high signal to the transistor 55 constituting the output voltage setting means 54 and outputs a low signal to the transistor 56. The transistor 55 is turned on in response to this high signal, is connected to a 4V Zener diode that constitutes the output voltage detection circuit 47, the detection voltage is set to 4V, and the output voltage of the first DC power supply circuit 45 is It is controlled to be 4V.

  When the output voltage of the first DC power supply circuit 45 is 4V, the output voltage of the second DC power supply circuit 14 is about 3.3V. This is because the circuit configuration of the second DC power supply circuit 14 is an emitter follower circuit, so that a voltage drop between the base and the emitter of the transistor constituting the emitter follower circuit is generated by about 0.7V. Since the operation guarantee range of the microcomputer 51 of the present embodiment is 2.3 V to 5.5 V, the microcomputer 51 can operate normally even if the output voltage of the second DC power supply circuit 14 is about 3.3 V. .

When the output voltage of the first DC power supply circuit 45 is 4V, the voltage applied to the control means 50 is lower than when the output voltage is 7V and 12V, so even if the current consumption is the same, The power consumption of the control means 50 can be reduced. Further, since the first DC power supply circuit 45 is constituted by the switching power supply 46, the conversion efficiency from the DC voltage of about 141V to the DC voltage of about 4V is higher than that of the power supply transformer, and the power consumption of the relay control device is reduced. Can be reduced.

  When a desired switch is pressed according to the display on the operation panel 81 in FIG. 5 in the above state, the switch on the first circuit board 80 is pressed via the operation panel 81, and the rice cooking sequence corresponding to the switch To start.

  For example, when a switch on the operation panel 81 is pressed, the microcomputer 51 constituting the control means 50 outputs a low signal to the transistor 55 constituting the output voltage setting means 54 at time t0 in FIG.

  When the transistor 55 is turned off in response to this low signal, the 12V Zener diode that constitutes the output voltage detection circuit 47 is connected, the detection voltage is set to 12V, and the first direct current is set so that the output voltage is 12V. The power supply circuit 45 is controlled.

  The time from the 4 V output voltage to the 12 V output voltage is determined by the output current supply capability of the first DC power supply circuit 45. In this embodiment, it takes about 25 ms for the output voltage to change from 4V to 12V.

  At time t1, 40 ms has elapsed since the transistor 55 was turned off. A high signal is output from the zero voltage synchronization signal generating means 57 to the microcomputer 51 at time t1. The timer means 61 in the microcomputer 51 uses the edge of the high signal as a trigger to measure the time until the set time set by the timing setting means 62 is reached. As described with reference to FIG. 4, the timing setting unit 62 can set an arbitrary set time from the four set times Ts1, Ts2, Ts3, and Ts4 stored in advance in the ROM built in the microcomputer 51. In the present embodiment, there are a first relay and a second relay, but the timing setting means 62 can set a set time for each relay, and the timing setting means 62 is set to Ts1 (0 ms) at the start of the rice cooking sequence. ) Is set.

  At time t1, since the set time Ts1 set by the timing setting means 62 is 0 ms, when the high signal of the zero voltage synchronization signal generating means 57 is output, the microcomputer 51 constituting the control means 50 is immediately driven first. A high signal is output to the circuit 52. When a high signal is output to the first drive circuit 52, the timing setting unit 62 changes the set time for sending the high signal to the first drive circuit 52 to Ts3 (10 ms). At the same time, the microcomputer 51 starts time measurement using a built-in timer.

  When the transistor constituting the first drive circuit 52 is turned on, the first relay coil 48 is energized. At this time, the current supply of the first relay coil 48 is supplied from the first DC power supply circuit 45. Since the first DC power supply circuit 45 is controlled so that the output voltage becomes 12V, even if a current flows through the first relay coil 48, there is almost no voltage drop.

  When the first relay coil 48 is energized, the first relay contact 43 is driven by the electromagnetic force of the coil. Since the first relay contact 43 moves and connects and opens the contact, it takes time until the first relay contact 43 is connected and the first heater 41 is turned on. In the present embodiment, at time t2 after about 7 ms, the first relay contact 43 is connected, the current path of the first heater 41 becomes conductive, the first heater 41 generates heat, and FIG. The bottom surface of the pan 75 is heated.

  At time t3, 90 ms has elapsed from time t1. The microcomputer 51 measures this elapsed time with a built-in timer, and outputs a high signal to the transistor 56 constituting the output voltage setting means 54 when measuring that 90 ms has elapsed.

  When the transistor 56 is turned on in response to this high signal, the 7V Zener diode that constitutes the output voltage detection circuit 47 is connected, the detection voltage setting value becomes 7V, and the first direct current is set so that the output voltage becomes 7V. The power supply circuit 45 is controlled.

  Until the output voltage of the first DC power supply circuit 45 drops from 12V to 7V, the power semiconductor built-in control circuit 9 does not perform the switching operation. That is, the time from the output voltage of 12 V to the output voltage of 7 V is determined by the capacity of the capacitor 11 constituting the first DC power supply circuit 45 and the resistance value of the first relay coil 48. In this embodiment, it takes about 15 ms for the output voltage to change from 12V to 7V. In the present embodiment, the DC voltage that allows the holding current of the first relay coil 48 to flow is 5 V. Therefore, if the output voltage of the first DC power supply circuit 45 is set to 7 V, a current equal to or higher than the holding current is supplied. be able to. At the same time, since the output voltage to the second DC power supply circuit 14 becomes 7V, the loss of the second DC power supply circuit 14 can be suppressed, and the relay control device excluding the power of the load (first heater 41). Power consumption can be reduced.

  At the time t4, for example, the moisture of the cooking object inside the pan 75 in FIG. Therefore, in order to turn on the second heater 42 that heats the lid heating plate 76, the microcomputer 51 outputs a low signal to the transistor 56 constituting the output voltage setting means 54. When the transistor 56 receives a low signal and is turned off, the 12V Zener diode constituting the output voltage detection circuit 47 is connected, the detection voltage is set to 12V, and the first DC power supply circuit is set to 12V. 45 is controlled.

  The time from the output voltage of 7V to the output voltage of 12V is the supply capacity of the output current of the first DC power supply circuit 45, the resistance value of the first relay coil 48, and the capacitor constituting the first DC power supply circuit 45. 11 is determined. In this embodiment, it takes about 15 ms for the output voltage to change from 7V to 12V.

  At time t5, 40 ms has elapsed since the transistor 56 was turned off. At time t5, a high signal is output from the zero voltage synchronization signal generating means 57 to the microcomputer 51. The timer means 61 in the microcomputer 51 uses the edge of the high signal as a trigger to measure the time until the set time set by the timing setting means 62 is reached. As described with reference to FIG. 4, the timing setting unit 62 can set an arbitrary set time from the four set times Ts1, Ts2, Ts3, and Ts4 stored in advance in the ROM built in the microcomputer 51. In the present embodiment, there are a first relay and a second relay, but the timing setting means 62 can set a set time for each relay, and the timing setting means 62 is set to Ts1 (0 ms) at the start of the rice cooking sequence. ) Is set. Since the second relay is turned on for the first time at time t5, Ts1 (0 ms) is set as the set time.

  Since the set time Ts1 set by the timing setting means 62 is 0 ms at time t5, the microcomputer 51 immediately sends a high signal to the second drive circuit 53 when the high signal of the zero voltage synchronization signal generating means 57 is output. Output. When a high signal is output to the second drive circuit 53, the timing setting means 62 changes the set time for sending the high signal to the second drive circuit 53 to Ts3 (10 ms). At the same time, the microcomputer 51 starts time measurement using a built-in timer.

When the transistor constituting the second drive circuit 53 is turned on, the second relay coil 49 is energized. At this time, the current supply of the second relay coil 49 is supplied from the first DC power supply circuit 45. Since the first DC power supply circuit 45 is controlled so that the output voltage becomes 12V, even if a current flows through the second relay coil 49 and the first relay coil 48, there is almost no voltage drop.

  When the second relay coil 49 is energized, the second relay contact 44 is driven by the electromagnetic force of the coil. Since the second relay contact 44 moves and connects and opens the contact, it takes time until the second relay contact 44 is connected and the first heater 42 becomes conductive. In the present embodiment, at time t6 after about 5 to 6 ms, the second relay contact 44 is connected, the current path of the second heater 42 becomes conductive, the second heater 42 generates heat, The lid heating plate 76 is heated via the 5 lid heat radiating plate 78.

  At time t7, 110 ms has elapsed since time t5. The microcomputer 51 measures this elapsed time with a built-in timer, and outputs a high signal to the transistor 56 constituting the output voltage setting means 54 when measuring that 90 ms has elapsed.

  When the transistor 56 is turned on in response to this high signal, the 7V Zener diode that constitutes the output voltage detection circuit 47 is connected, the detection voltage setting value becomes 7V, and the first direct current is set so that the output voltage becomes 7V. The power supply circuit 45 is controlled.

  Until the output voltage of the first DC power supply circuit 45 drops from 12V to 7V, the power semiconductor built-in control circuit 9 does not perform the switching operation. That is, the time from the 12V output voltage to the 7V output voltage is determined by the capacitance of the capacitor 11 constituting the first DC power supply circuit 45 and the combined resistance value of the first relay coil 48 and the second relay coil 49. Determined. In this embodiment, it takes about 15 ms for the output voltage to change from 12V to 7V.

  In the present embodiment, the DC voltage that allows the holding current of the first relay coil 48 and the second relay coil 49 to flow is 5 V. Therefore, if the output voltage of the first DC power supply circuit 45 is 7 V, the holding voltage is maintained. A current higher than the current can be supplied. At the same time, since the output voltage to the second DC power supply circuit 14 becomes 7 V, the loss of the second DC power supply circuit 14 can be suppressed, and the power of the load (first heater 41, second heater 42) can be suppressed. It is possible to reduce the power consumption of the relay control device except for.

  When the first heater 41 generates heat for a while, the bottom surface of the pan 75 is heated, and the temperature of the bottom surface rises. When the temperature detection means 84 in FIG. 5 detects that the bottom surface temperature of the pan 75 has increased, the microcomputer 51 operates to stop the first heater 41.

  Next, when the zero voltage synchronization signal generating means 57 outputs a high signal at time t8 in FIG. 7, the timer means 61 built in the microcomputer 51 starts measuring time.

  When the measurement time of the timer means 61 reaches the set time Ts3 (10 ms) at time t9, the microcomputer 51 outputs a low signal to the first drive circuit 52. When receiving the low signal, the transistors constituting the first drive circuit 52 are turned off, and the energization of the first relay coil 48 is stopped. Since no current flows through the first relay coil 48, the electromagnetic force of the coil is lost, the force for driving the first relay contact 43 is lost, and the first relay contact 43 is opened. When the first relay contact 43 is in an open state, the current path of the first heater 41 is interrupted, no current flows through the first heater 41, and the first heater 41 stops generating heat.

When the bottom surface temperature of the pan 75 falls and the temperature detecting means 84 detects it, it is necessary to heat the first heater 41 again to heat the pan 75.

  At time t10, control is performed to set the output voltage of the first DC power supply circuit 45 to 12 V so that a current equal to or greater than the moving current flows through the first relay coil 48. The microcomputer 51 outputs a low signal to the transistor 56 constituting the output voltage setting means 54. When the transistor 56 receives a low signal and is turned off, the 12V Zener diode constituting the output voltage detection circuit 47 is connected, the detection voltage is set to 12V, and the first DC power supply circuit is set to 12V. 45 is controlled.

  The time from the output voltage of 7V to the output voltage of 12V is the supply capacity of the output current of the first DC power supply circuit 45, the resistance value of the second relay coil 49, and the capacitor constituting the first DC power supply circuit 45. 11 is determined. In this embodiment, it takes about 15 ms for the output voltage to change from 7V to 12V.

  At time t11, 40 ms has elapsed since the transistor 56 was turned off. A high signal is output from the zero voltage synchronization signal generating means 57 to the microcomputer 51 at time t11. The timer means 61 in the microcomputer 51 starts measuring time using the edge of the high signal as a trigger.

  When the measurement time of the timer means 61 reaches the set time Ts3 (10 ms) set by the timing setting means 62 at time t12, the microcomputer 51 outputs a high signal to the first drive circuit 52. When a high signal is output to the first drive circuit 52, the timing setting unit 62 changes the set time for sending the high signal to the first drive circuit 52 to Ts2 (5 ms). At the same time, the microcomputer 51 starts time measurement using a built-in timer.

  When the transistor constituting the first drive circuit 52 is turned on, the first relay coil 48 is energized. At this time, the current supply of the first relay coil 48 is supplied from the first DC power supply circuit 45. Since the first DC power supply circuit 45 is controlled so that the output voltage becomes 12V, even if a current flows through the first relay coil 48 and the second relay coil 49, there is almost no voltage drop.

  When the first relay coil 48 is energized, the first relay contact 43 is connected by the electromagnetic force of the coil, and the first heater 41 becomes conductive. In the present embodiment, at time t13 after about 7 ms, the first relay contact 43 is connected, the current path of the first heater 41 becomes conductive, the first heater 41 generates heat, and the pan 75 is removed. Heat.

  At time t14, 90 ms has elapsed since time t12. The microcomputer 51 measures this elapsed time with a built-in timer, and outputs a high signal to the transistor 56 constituting the output voltage setting means 54 when measuring that 90 ms has elapsed.

  When the transistor 56 is turned on in response to this high signal, the 7V Zener diode that constitutes the output voltage detection circuit 47 is connected, the detection voltage setting value becomes 7V, and the first direct current is set so that the output voltage becomes 7V. The power supply circuit 45 is controlled.

Until the output voltage of the first DC power supply circuit 45 drops from 12V to 7V, the power semiconductor built-in control circuit 9 does not perform the switching operation. That is, the time from the 12V output voltage to the 7V output voltage is determined by the capacitance of the capacitor 11 constituting the first DC power supply circuit 45 and the resistance values of the first relay coil 48 and the second relay coil 49. . In this embodiment, it takes about 15 ms for the output voltage to change from 12V to 7V. In the present embodiment, the DC voltage that allows the holding current of the first relay coil 48 and the second relay coil 49 to flow is 5 V. Therefore, if the output voltage of the first DC power supply circuit 45 is 7 V, the holding voltage is maintained. A current higher than the current can be supplied. At the same time, since the output voltage to the second DC power supply circuit 14 becomes 7V, the loss of the second DC power supply circuit 14 can be suppressed, and the relay control device excluding the power of the load (first heater 41). Power consumption can be reduced.

  Thereafter, when the temperature of the lid heating plate 76 becomes high, the microcomputer 51 performs an operation of stopping the second heater 76.

  At time t15, when the zero voltage synchronization signal generating means 57 outputs a high signal at time t8, the timer means 61 built in the microcomputer 51 starts measuring time.

  When the measurement time of the timer means 61 reaches the set time Ts3 (10 ms) at time t16, the microcomputer 51 outputs a low signal to the second drive circuit 53. When receiving the low signal, the transistors constituting the second drive circuit 53 are turned off, and the energization of the second relay coil 49 is stopped. Since no current flows through the second relay coil 49, the electromagnetic force of the coil is lost, the force for driving the second relay contact 44 is lost, and the second relay contact 44 is opened. When the second relay contact 44 is in an open state, the current path of the second heater 42 is interrupted, no current flows through the second heater 42, and the second heater 42 stops generating heat.

  As described above, in the relay control device according to the present embodiment, the output of the first DC power supply circuit 45 that supplies current to the first relay coil 48 and the second relay coil 49 even when there are a plurality of relays. By controlling the voltage by the control means 50, it is possible to switch between a moving voltage that can supply a moving current to each relay coil and a holding voltage that can supply a holding current to the relay coil at a desired timing. The loss of the current and the second DC power supply circuit 14 that supplies power to the control means 50 can be suppressed. In addition, in order to reduce the current consumption of the relay coil, a current limiting resistor may be connected in series to the relay coil, but this is not necessary. Furthermore, when this current limiting resistor is connected in series, a capacitor may be connected in parallel to the relay coil in order to secure a current when the relay coil is activated, but this capacitor is also unnecessary.

  Further, the control means 50 turns on or off the relay from the timing time set by the timing setting means 62 and the output of the timer means 61, and the timing setting means 62 makes the timing time alternate between positive and negative phases of the AC power supply 1. Since the change is made, the average value of the current flowing through the contact of the relay is made almost zero, so that the metal transfer of the relay contact can be suppressed and the durability of the relay contact can be lengthened.

  Also, when all relays are off, the output signal of the first DC power supply circuit that supplies current to the relays is made smaller than the holding voltage, so that an ON signal is output to the relays due to the effects of external noise, etc. However, sufficient electromagnetic force is not generated in the relay coil, and the relay contact can be prevented from being connected.

  In the relay control device of the present embodiment, the first relay coil 48 and the second relay coil 49 have the same moving current and holding voltage, but relays having different moving current and holding current may be used. Absent. In this case, when a moving current is required, the output voltage can be set according to the relay with the larger moving current. When a holding current is required, the output voltage is set according to the relay with the larger holding current. You only have to set it. By doing so, the set value of the output voltage of the first DC power supply circuit 45 when driving the relay can be made two, so that the combination of the relay and the moving current or the holding current is not mistaken. Can be driven.

  In the relay control device of the present embodiment, although not shown, a voltage detection means for detecting the output voltage of the first DC power supply circuit 45 is provided separately from the output voltage detection circuit 47. Depending on the detection voltage, the relay can be turned off or released. If the output voltage of the first DC power supply circuit 45 is detected by the voltage detection means, the first DC power supply circuit 45 as shown in FIG. 3, FIG. 6, and FIG. It is possible to determine whether the output voltage of the DC power supply circuit 45 is a voltage that can flow more than the moving current of the relay coil, and to drive the relay in the shortest time. If the voltage detection means is constituted by a resistance voltage dividing circuit and is input by an AD converter built in the microcomputer, it is determined whether or not the microcomputer outputs the voltage set by the first DC power supply circuit 45. In addition, a failure of the first DC power supply circuit 45 can be detected early.

  5 is used to estimate the temperature of the second circuit board 82 on which the relay is mounted, and to estimate the resistance value of the relay coil. The output voltage of the power supply circuit 45 may be adjusted. Since the resistance value of the relay coil changes depending on the temperature, it is necessary to adjust the output voltage of the first DC power supply circuit 45 to make the current supplied to the relay coil constant, but by using the temperature detection means, The minimum necessary current can be supplied, and the power consumption when the relay coil is energized can be minimized.

  Moreover, in the rice cooker as a cooking appliance of this Embodiment, since the above-mentioned relay control apparatus was provided, since a relay can be used over a long period of time, a cooking appliance with a long product life can be provided.

  In the present embodiment, the load is described as a heater, but a motor for stirring dough may be used as a load in a home bakery or the like for manufacturing bread, and this motor may be turned on and off by a relay.

  As described above, the relay control device according to the present invention can set the output voltage of the power supply circuit (first DC power supply circuit) that supplies current to the coil of the relay by the control means. The output voltage of the first DC power supply circuit that supplies current to the relay coil can be switched from a voltage that is higher than the moving voltage that can supply the moving current to a voltage that is higher than the holding voltage that can supply the holding current. The components of the DC power supply circuit are not affected by the aging deterioration, the parts can be downsized and the relay control device can be guaranteed for a long time, and the cooking appliance according to the present invention can use the relay for a long time. Since a cooking device with a long life can be provided, a relay control device that controls a load such as a heater with a relay and a cooking device equipped with the relay control device It is useful.

1 is a partial block diagram of a relay control apparatus according to Embodiment 1 of the present invention. Sectional view of cooking equipment equipped with the relay control device Operation time chart of the relay controller Circuit diagram in which the relay control device according to Embodiment 2 of the present invention is partly blocked Cross section of rice cooker as cooking equipment equipped with the relay control device The figure which shows a part (first half) of the operation time chart of the relay control device The figure which shows the continuation (second half) of the operation time chart of the relay control device

Explanation of symbols

1 AC power supply 2 Heater (load)
3 Relay contact (relay)
4 First DC power supply circuit 13 Relay coil (relay)
14 Second DC power supply circuit 15 Control means

Claims (9)

An AC power supply, a load, a relay that conducts or cuts off a current path between the load and the AC power supply, a first DC power supply circuit that converts the AC power supply into a DC power supply, and an output of the first DC power supply circuit A second DC power supply circuit for converting the voltage to a voltage lower than the output voltage of the first DC power supply circuit; and a control means for controlling conduction and interruption of the relay by receiving power supply from the second DC power supply circuit The first DC power supply circuit has a plurality of output voltages, and the driving power of the relay is supplied from the first DC power supply circuit in accordance with a control signal of the control means , The DC power supply circuit is composed of a switching power supply having a supply capability that does not drop even when the moving current of the relay is supplied, and when the control means conducts the relay, the output voltage of the first DC power supply circuit is set. Above Is set more than impressed voltage capable of supplying impressed current rate, sets the output voltage of the first DC power supply circuit from starting conduction after a predetermined period of time of the relay beyond the holding voltage that can be supplied holding current of the relay, When the relay is cut off, the output voltage of the first DC power supply circuit is set to a value lower than the moving voltage capable of supplying the moving current of the relay, and the output of the first DC power supply circuit is turned on before the relay is turned on. A relay control device configured to set the voltage to be greater than or equal to the moving voltage. Control means, while blocking the relay, the relay control device according to claim 1, wherein so as to set to a value lower than the holding voltage to the output voltage of the first DC power supply circuit capable of supplying a holding current of the relay. Voltage detecting means for detecting the output voltage of the first DC power supply circuit is provided, and when the control means conducts the relay, if the voltage detected by the voltage detecting means is equal to or less than the moving voltage of the relay, the relay is conducted. 2. The relay control device according to claim 1, wherein control is performed so as not to start. From the zero voltage synchronization signal generating means for generating a signal synchronized with the zero voltage of the AC power supply, the timer means for measuring the time from the output of the zero voltage synchronization signal generating means, and the output signal of the zero voltage synchronization signal generating means Timing setting means for setting a timing time until the relay is turned on or off, and the control means turns on or off the relay from the timing time set by the timing setting means and the output of the timer means, and the timing setting The relay control device according to claim 1, wherein the means changes the timing time so that the positive and negative phases of the AC power supply are alternated. A plurality of loads, and a plurality of relays for conducting or blocking each of the current paths of the plurality of loads and the AC power supply, and the control unit is configured to perform other operations when conducting any one of the plurality of relays. Regardless of whether the relay of the relay is in a conductive state or a disconnected state, the output voltage of the first DC power supply circuit is set to be equal to or higher than the moving voltage that can supply the moving current of the relay, 2. The relay control device according to claim 1, wherein the output voltage of the DC power supply circuit is set to be equal to or higher than a holding voltage capable of supplying a holding current of the relay. Two or more relays having different moving currents are provided, and the control means outputs the first DC power supply circuit so as to obtain a moving voltage capable of supplying the largest moving current among the different moving currents when the relays are turned on. The relay control device according to claim 5 , wherein the voltage is set. When two or more relays having different holding currents are provided, and the control means also conducts the relays, the output of the first DC power supply circuit is set so as to obtain a moving voltage capable of supplying the largest moving current among the different moving currents. The voltage is set, and the output voltage of the first DC power supply circuit is set so as to be a holding voltage that can supply the largest holding current among the different holding currents after a predetermined time has elapsed after the relay is turned on. The relay control device according to claim 6 . The relay control device according to claim 1, further comprising a temperature detection unit that detects a temperature in the vicinity of the relay, wherein the control unit changes an output voltage of the first DC power supply circuit in accordance with an output of the temperature detection unit. Cooking equipment provided with the relay control device according to any one of claims 1 to 8 .

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