JP2008104326A - Power supply controller and washing dryer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply controller which can cope with a heavy load by achieving an overvoltage protection function through simple circuitry without enlarging a surge absorber. <P>SOLUTION: The power supply controller comprises a control circuit 2 for supplying power from an AC power supply 1 to a load 3 under predetermined control, a power supply relay 5 connected in series with the control circuit, a power switch 4 connected in parallel with the power supply relay, a series circuit of a surge absorber 8 and a fuse 7 connected between the AC power supply and the control circuit in parallel with the control circuit, and a circuit 9 for detecting voltage application from the AC power supply across the surge absorber and inputting the detection output to the control circuit. On condition that voltage application is detected by the AC power supply detection circuit, the control circuit can turn on the power supply relay, and keeps ON state of the power supply relay on condition that voltage application is detected by the AC power supply detection circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power supply control device that supplies power from an AC power source to a load through predetermined control, and more particularly, a power supply control device having an overvoltage protection circuit including a protective fuse and a surge absorber, and washing and drying using the same Related to the machine.

  A power supply control device having an overvoltage protection circuit is widely used in household appliances and the like. As an example of the overvoltage protection circuit, one using a surge absorber and a fuse as shown in FIG. 3 is known (for example, see Patent Document 1).

  In FIG. 3, the power of the AC power source 1 is supplied to the load 3a through the control circuit 2a through a predetermined control. For example, the load 3a is a motor, and the control circuit 2a is an inverter circuit that drives the motor. A power relay 5 is connected in series with the control circuit 2 a, and a power switch 4 is connected in parallel with the power relay 5. The overvoltage protection circuit includes a fuse 6a connected in series to the control circuit 2a, and a surge absorber 8 connected in parallel with the control circuit 2a between the fuse 6a and the control circuit 2a.

  When the power switch 4 is turned on to start the operation of this circuit, power is supplied from the AC power source 1 to the control circuit 2a, and the control circuit 2a turns on and holds the power relay 5. In this circuit, if an overvoltage is applied by mistake and the voltage applied to the control circuit 2a is about to be higher than the set voltage of the surge absorber 8, the surge absorber 8 is short-circuited and a large current flows, and the fuse 6a is blown. Thereby, application of overvoltage to the control circuit 2a is avoided, and the control circuit 2a can be protected. The surge absorber 8 needs to be large enough to pass a current larger than the capacity of the fuse 6a.

  The power supply control device having the overvoltage protection circuit as described above is also used in, for example, a washing machine. FIG. 4 shows an example of a control device used in the washing / drying machine. In this control apparatus, the AC power of the commercial power supply 20 is rectified by the rectifier 21 and the DC power smoothed by the smoothing circuit including the choke coil 22 and the smoothing capacitor 23 is used as the driving power, and the drum driving motor 25 is driven by the inverter circuit 24. Is driven to rotate.

  The drum drive motor 25 includes a stator having three-phase windings 25a, 25b, and 25c and a rotor having two-pole permanent magnets, and is configured as a DC brushless motor provided with three position detection elements 26a, 26b, and 26c. Then, the rotation is controlled by the PWM control inverter circuit 24 constituted by the switching elements 24a to 24f. The rotor position detection signals detected by the position detection elements 26a, 26b, and 26c are input to the control unit 27 that is configured by a microcomputer, and the driving circuit 28 turns on / off the switching elements 24a to 24f based on the rotor position detection signals. Is controlled by PWM to control the energization of the three-phase windings 25a, 25b, 25c of the stator to rotate the rotor at the required rotational speed.

  Further, the rotation of the drum drive motor 25 is controlled based on the operation instruction input from the input setting unit 29 and the monitoring information of the operation state detected by each detection means (not shown), and the load drive unit 30 The operation of the water supply valve 31, the drain valve 32, the blower fan 33, and the compressor 34 is controlled.

  The compressor 34 constitutes a heat pump cycle. The heat pump cycle is composed of a compressor, an evaporator that absorbs heat, a condenser that generates heat, and a capillary tube, and functions as a dehumidifier that removes moisture by introducing moist air from the washing tub during drying.

  As described above, the washing and drying machine has the load driving unit 30 in addition to the driving circuit 28 of the drum driving motor 25, and the compressor 34 in particular becomes a heavy load. Although an overvoltage protection circuit for the control device is not shown, it can be inserted between the commercial power supply 20 and the load drive circuit 30. However, when applied to this control device, the overvoltage protection circuit shown in FIG. 3 needs to have a sufficient capacity of the fuse 6a. If only the drive circuit 28 of the drum drive motor 25 is used, the fuse 6a may be 7A, for example. However, when the compressor 34 is added, the fuse 6a needs to have a capacity of, for example, 16A.

  However, in order to flow a current of 16 A or more so that the fuse 6a is blown when an overvoltage is applied, the surge absorber 8 needs to be considerably large, which is not practical in terms of cost and mounting.

  Therefore, a configuration of an overvoltage protection circuit as shown in FIG. 5 has been proposed. In FIG. 5, the washing load 3 b corresponds to the drum drive motor 25, and the compressor load 3 c corresponds to the motor of the compressor 34. The electric power from the AC power supply 1 is branched into two systems, and the washing load 3b and the compressor load 3c are driven by the first control circuit 2b and the second control circuit 2c, respectively. The overvoltage protection circuit connected to the first control circuit 2b has the same configuration as that shown in FIG. The second control circuit 2c to which the compressor load 3c is connected is connected to the AC power supply 1 in parallel with the first control circuit 2b, and between one terminal of the AC power supply 1 and the second control circuit 2c, A fuse 6b is connected. A power relay 5b is connected between the other terminal of the AC power source 1 and the second control circuit 2c. The power relay 5b is held in an ON state by a control signal from the first control circuit 2b.

  In this circuit, if an overvoltage is accidentally applied and the voltage applied to the first control circuit 2b attempts to reach a state equal to or higher than the set voltage of the surge absorber 8, the surge absorber 8 is short-circuited, current flows, and the fuse 6a is blown. . At the same time, since the control signal from the first control circuit 2b is turned off, the power supply relay 5b is turned off, and the second control circuit 2c is also cut off from the AC power supply 1 and protected from overvoltage.

As described above, when a large current flows in the surge absorber 8 due to overvoltage, the fuse 6a inserted between the AC power supply 1 and the first control circuit 2b is blown, whereby the first control circuit 2b and the second control circuit. The effect of overvoltage protection for both 2c is obtained. The fuse 6a only needs to have a capacity corresponding to the first control circuit 2b, that is, the washing load 3b, and is smaller than the capacity corresponding to the combined load of the washing load 3b and the compressor load 3c. There is no need to increase the size of the absorber 8.
JP 2002-359921 A

  However, the circuit having the configuration shown in FIG. 5 has a complicated configuration because the wiring from the power supply branches into two systems and a power relay is provided for each of them, and increases the cost of parts and manufacturing.

  Accordingly, an object of the present invention is to provide a power supply control device that can realize an overvoltage protection function with a simple circuit configuration and can cope with a large load without increasing the size of a surge absorber.

  In order to solve the above-described problems, a power supply control device according to the present invention includes a control circuit that supplies power from an AC power source to a load through a predetermined control, a power relay connected in series with the control circuit, and the power source. A power switch connected in parallel with a relay, a series circuit of a surge absorber and a fuse connected in parallel with the control circuit between the AC power supply and the control circuit, and the AC power supply for both ends of the surge absorber An AC power supply detection circuit that detects the presence or absence of voltage application and inputs the detection output to the control circuit, and the control circuit is provided that the voltage application is detected by the AC power supply detection circuit. The power relay can be turned on, and the power relay is turned on on condition that the application of the voltage is detected by the AC power supply detection circuit. It controls to hold a state.

  According to the power supply control device of the present invention, the fuse connected in series with the surge absorber is blown by the current flowing through the surge absorber due to overvoltage and is used only to shut off the AC power supply to the surge absorber. It is not necessary to secure a capacity according to the load of the circuit. As a result, the size of the surge absorber can be set as appropriate without being constrained by the load of the control circuit, and the overvoltage protection function can be realized with a simple circuit configuration to handle a large load. Become.

  In the power supply control device of the present invention configured as described above, the voltage applied to the control circuit when the power switch is turned on is connected in parallel with the control circuit between the power switch and the control circuit. A voltage detection circuit that detects and inputs the voltage to the control circuit, and the control circuit detects that the detected voltage of the voltage detection circuit is within a predetermined range after the application of the voltage is detected by the AC power supply detection circuit. It is preferable that the power relay is turned on when detected.

  Further, the control circuit is configured such that when the power supply relay is in an ON state, when the voltage application is not detected by the AC power supply detection circuit, or the detection voltage of the voltage detection circuit is out of a predetermined range. In some cases, the power relay is preferably turned off.

  The washing and drying machine of the present invention includes a rotating drum for storing laundry and washing and drying, a water tank that rotatably includes the rotating drum and elastically supported in the washing machine body, and a compressor A dehumidifying device that dehumidifies moist air by a heat pump cycle comprising an evaporator, a condenser, and a capillary tube, and sends the moist air in the washing tub when the laundry is dried to the dehumidifying device A blower, a drum drive motor that drives the rotating drum, and a control circuit that controls the supply of electric power to a load including the compressor motor that drives the compressor. A configuration using a control circuit can be employed.

  Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings.

(Embodiment 1)
FIG. 1 is a circuit diagram showing a configuration of a power supply control apparatus according to Embodiment 1 of the present invention. The power of the AC power source 1 is supplied to the load 3 through the control circuit 2 through a predetermined control. The load 3 includes, for example, two inverter circuits for driving a drum drive motor and a compressor motor in a washing / drying machine, and the control circuit 2 includes an inverter drive control circuit for controlling the inverter circuits. can do. A first fuse 6 is connected in series between one terminal of the AC power supply 1 and the control circuit 2. A power relay 5 is connected in series with the other terminal of the AC power source 1 and the control circuit 2, and a power switch 4 is connected in parallel with the power relay 5.

  A series circuit of a second fuse 7 and a surge absorber 8 is connected between the first fuse 6 and the control circuit 2 in parallel with the control circuit 2 to constitute an overvoltage protection circuit. An AC power supply detection circuit 9 is connected to both ends of the surge absorber 8. The AC power supply detection circuit 9 detects the presence or absence of voltage application from the AC power supply 1 at both ends of the surge absorber 8 and inputs the detection output to the control circuit 2. The AC power supply detection circuit 9 is constituted by a series circuit of a resistor 10 and a diode 11 connected in parallel to the surge absorber 8, detects the voltage at both ends of the surge absorber 8, and detects a pulse train detection signal via the photocoupler 12. Is input to the control circuit 2.

  The control circuit 2 makes it possible to turn on the power supply relay 5 on the condition that the voltage application is detected by the AC power supply detection circuit 9 and the voltage application is detected by the AC power supply detection circuit 9. Under the condition, control is performed so as to maintain the ON state of the power supply relay 5. That is, the power supply relay 5 is turned on when the power switch 4 is turned on while the application of voltage is detected by the AC power supply detection circuit 9. Further, when the application of voltage is no longer detected by the AC power supply detection circuit 9, the power supply relay 5 is turned off.

  According to the above configuration, when an overvoltage occurs, a large current flows through the surge absorber 8, the control circuit 2 is protected from the overvoltage, and the second fuse 7 is blown, so that the surge absorber 8 has an AC current. The voltage from the power source 1 is not applied. Therefore, the AC power supply detection circuit 9 does not receive the output indicating the voltage application to the control circuit 2, and the control circuit 2 cancels the ON state of the power supply relay 5. In addition, since the detection signal of voltage application is not output from the AC power supply detection circuit 9, the power supply relay 5 will not be turned on even if the power switch 4 is turned on, and the overvoltage protection by the surge absorber 8 is not activated. Driving is avoided.

  In order to operate the overvoltage protection function in the circuit of FIG. 1, the surge absorber 8 only needs to be able to flow a current that is sufficient to blow the second fuse 7. On the other hand, the protection against the overcurrent that flows due to the problem on the control circuit 2 side is performed by the first fuse 6 being blown, so that the load on the control circuit 2 is increased against the first What is necessary is just to set the capacity | capacitance of the fuse 6 large. That is, the second fuse 7 is blown by a current flowing through the surge absorber 8 due to an overvoltage and is used only to shut off the AC power supply 1 with respect to the surge absorber 8, so that the second fuse 7 corresponds to the load of the control circuit 2. There is no need to secure capacity. As a result, the size of the surge absorber 8 can be set as appropriate without being restricted by the load of the control circuit 2. As described above, according to the present embodiment, only one wiring from the power source and one power relay are required, and the circuit can be protected from overvoltage with a simple and inexpensive configuration.

(Embodiment 2)
FIG. 2 is a circuit diagram showing a configuration of the power supply control apparatus according to Embodiment 2 of the present invention. The basic configuration of this circuit is the same as that shown in FIG. 1, and the same components are denoted by the same reference numerals, and the description thereof will not be repeated.

  The circuit of the present embodiment is different from the circuit of the first embodiment in that a voltage detection circuit 13 connected in parallel with the control circuit 2 is provided between the power supply relay 5 and the control circuit 2. is there. The voltage detection circuit 13 detects a voltage applied to the control circuit 2 when the power switch 4 is turned on, and inputs the detection voltage to the control circuit 2.

  After the voltage application is detected by the AC power supply detection circuit 9, the control circuit 2 turns on the power supply relay 5 when detecting that the voltage detected by the voltage detection circuit 13 is within a predetermined range. The predetermined range of the detection voltage by the voltage detection circuit 13 is set to such a voltage that it is not desired to be applied to the control circuit 2 although the surge absorber 8 is not operated and the second fuse 7 is blown. .

  By providing the voltage detection circuit 13 and operating it as described above, it is possible to suppress an undesirable overvoltage from being applied to the control circuit 2 although the surge absorber 8 does not operate. Further, even when the second fuse 7 cannot be blown due to a component failure, the control circuit 2 can be protected.

  Also, the control circuit 2 is configured such that when the power supply relay 5 is in the ON state, voltage application is no longer detected by the AC power supply detection circuit 9, or the detection voltage of the voltage detection circuit 13 is out of a predetermined range. Then, the power supply relay 5 is turned off. Thereby, even when an overvoltage is applied during operation, the control circuit 2 can be protected.

  According to the power supply control device of the present invention, the overvoltage protection function can be realized with a simple circuit configuration without increasing the size of the surge absorber, and it is possible to cope with a large load, which is useful for a washing dryer and the like.

The circuit diagram which shows the power supply control apparatus in Embodiment 1 of this invention The circuit diagram which shows the electric power supply control apparatus in Embodiment 2 of this invention Circuit diagram showing a conventional power supply control device Circuit diagram showing schematic configuration of control device for washing and drying machine Circuit diagram showing another conventional power supply control device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2, 2a Control circuit 2b 1st control circuit 2c 2nd control circuit 3, 3a Load 3b Washing load 3c Compressor load 4 Power switch 5 Power supply relay 6 1st fuse 6a fuse 7 2nd fuse 8 Surge absorber 9 AC power supply detection circuit 10 Resistor 11 Diode 12 Photocoupler 13 Voltage detection circuit 20 Commercial power supply 24 Inverter circuit 25 Drum drive motor 27 Control unit 28 Drive circuit 30 Load drive unit 34 Compressor

Claims (4)

A control circuit for supplying the power of the AC power source to the load through a predetermined control;
A power relay connected in series with the control circuit;
A power switch connected in parallel with the power relay;
Between the AC power supply and the control circuit, a series circuit of a surge absorber and a fuse connected in parallel with the control circuit,
An AC power supply detection circuit that detects the presence or absence of voltage application from the AC power supply to both ends of the surge absorber and inputs the detection output to the control circuit;
The control circuit makes it possible to turn on the power relay on condition that the voltage application is detected by the AC power supply detection circuit,
A power supply control device, characterized in that control is performed so as to maintain an ON state of the power supply relay on condition that the application of voltage is detected by the AC power supply detection circuit. A voltage detection circuit that is connected in parallel with the control circuit between the power switch and the control circuit, and detects a voltage applied to the control circuit when the power switch is turned on and inputs the voltage to the control circuit With
2. The control circuit turns on the power relay when detecting that the detection voltage of the voltage detection circuit is within a predetermined range after the application of the voltage is detected by the AC power supply detection circuit. The power supply control device described in 1.   The control circuit is configured such that when the power supply relay is in an ON state, when the voltage application is no longer detected by the AC power supply detection circuit, or when the detection voltage of the voltage detection circuit is out of a predetermined range. The power supply control device according to claim 2, wherein the power supply relay is turned off. A rotating drum for accommodating laundry and washing and drying;
A water tub enclosing the rotating drum rotatably and elastically supported in the washing machine body;
A dehumidifying device for dehumidifying humid air by a heat pump cycle composed of a compressor, an evaporator, a condenser, and a capillary tube;
An air blower for sending moist air in the washing tub to the dehumidifier when drying the laundry;
A control circuit for controlling supply of electric power to a load including a drum drive motor for driving the rotary drum and a compressor motor for driving the compressor;
A washing / drying machine using a control circuit having the configuration according to claim 1 as the control circuit.

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