JP2008043004A - Power supply device and air cleaner using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device which can properly suppress a rush current at powering-on and heat generation at normal operation without the need for any control, and to provide an air cleaner using the power supply device. <P>SOLUTION: The power supply device comprises a power feeding circuit (AC-DC conversion circuit 301) which feeds drive power to loads (fan motor 101 and DC-AC conversion circuit 302), and a load characteristic thermistor 306 which is arranged on a power feeding line to the loads from the power feeding circuit, and whose resistance value is decreased as a temperature rises. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power supply device that supplies driving power to a load, and an air purifier using the same, and more particularly to a technique for suppressing inrush current when power is turned on and heat generation during normal operation.

  FIG. 5 is a circuit diagram showing a conventional example of an inrush current limiting circuit.

  In each of the inrush current limiting circuits shown in FIGS. 5A and 5B, an inrush current limiting resistor R and a resistor short-circuiting switch SW are connected in parallel on the power supply line from the power source X to the load Y. When the power is turned on, the switch SW is turned off to incorporate the resistor R into the power supply line, while during normal operation, the switch SW is turned on to short-circuit the resistor R.

  The inrush current limiting circuit of FIG. 5A has a conventional configuration using a transistor as the switch SW (see, for example, Patent Document 1), and the inrush current limiting circuit of FIG. This is a conventional configuration using a relay.

JP-A-2-303318

  Certainly, with the inrush current limiting circuit of FIGS. 5A and 5B, the inrush current can be effectively suppressed using the resistor R when the power is turned on, and the resistor R is used in the subsequent normal operation. By short-circuiting, it is possible to reduce heat generation and power consumption.

  However, in the inrush current limiting circuit shown in FIGS. 5A and 5B, the switch SW is necessary as means for short-circuiting the resistor R. Such separate installation of the switch SW is one factor that hinders the reduction of the chip area during circuit integration. In particular, when the conventional configuration shown in FIG. 5A is used as an inrush current limiting circuit of a power supply device that supplies driving power to a load (for example, a motor) that requires a large current, it is used as a switch SW. Since it is necessary to increase the element size in order to sufficiently increase the current capacity of the transistor, the above-described problem has become prominent.

  Further, in the conventional configuration in which the switch SW is separately installed, there is a possibility that not only the above-described problem but also a failure of the switch SW directly leads to a serious failure of the entire device. Specifically, when the switch SW fails, the resistor R is always inserted into the power supply line, or on the contrary, is always short-circuited. Or the temperature of the resistance R continuously increases during normal operation, and in the worst case, there is a risk of destruction of the device or smoke or ignition of the device.

  In view of the above problems, the present invention provides a power supply device capable of appropriately suppressing inrush current at power-on and heat generation during normal operation without requiring any control, and an air cleaner using the same. The purpose is to provide a machine.

  In order to achieve the above object, a power supply device according to the present invention is provided on a power supply circuit for supplying driving power to a load; and on a power supply line from the power supply circuit to the load. And a negative characteristic thermistor that lowers (a first configuration).

  In addition, an air cleaner according to the present invention includes a power supply device having the above first configuration; a fan motor that is driven using driving power from the power supply device to intake and exhaust indoor air; and And a filter that collects dust from the indoor air that has been sucked in (second configuration).

  More specifically, the air cleaner according to the present invention is driven to rotate by using the first DC voltage as an operating voltage, and rotates and sucks and exhausts indoor air; and rotates using the second DC voltage as an operating voltage. A motor control circuit that performs drive control of the fan motor in accordance with a speed control signal and generates a rotation speed signal indicating the rotation speed of the fan motor; an operation panel that receives a user operation; AC supplied from a commercial power supply An AC / DC conversion circuit that converts a voltage to a first DC voltage; a DC / DC conversion circuit that generates a second DC voltage from the first DC voltage; and the rotation speed signal and the user operation A microcomputer that generates a PWM signal for controlling the rotation speed of the fan motor; and a digital generator that generates the rotation speed control signal by converting the PWM signal into an analog signal A negative characteristic thermistor provided on a power supply line from the AC / DC conversion circuit to the fan motor and the DC / DC conversion circuit, and having a lower resistance value as the temperature increases; And a filter that collects dust from the indoor air that has been sucked in (third configuration).

  According to the present invention, the negative characteristic of the thermistor (high resistance is shown because the temperature is low immediately after the power is turned on, but when a predetermined time elapses after the power is turned on, the temperature rises due to self-heating due to energization and the resistance It is possible to appropriately suppress the inrush current when the power is turned on and the heat generation during the normal operation without using any control by utilizing the characteristic that the value decreases.

  Hereinafter, the case where the present invention is applied to a power supply device mounted on an air cleaner will be described in detail as an example.

  FIG. 1 is a perspective view showing an external appearance of an air cleaner according to the present invention.

  As shown in the figure, the air cleaner 1 has a main body 10 erected by the support of a base 11. The front surface of the main body 10 is covered with a front panel 12. A side air inlet 13 for taking in indoor air is formed by a gap between the main body 10 and the front panel 12. A first air outlet 14a is provided at an upper portion of the main body 10, and a second air outlet 14b that is bent obliquely upward and opens forward is provided. In addition, an operation panel 15 for a user to perform an operation is provided on the upper portion of the main body unit 10.

  FIG. 2 is a front view showing an example of the operation panel 15.

  As shown in the figure, the operation panel 15 includes various user operations (ion on / off, child lock on / off, air cleaning operation switching, ion shower on / off, humidification operation switching, reset, and operation on / off. In addition to the switch group (depicted with a square frame in the figure) that accepts the switch, the operating state of the device (ion on / off state, child lock on / off state, air cleaning operation state, ion shower operation state, humidification operation) Indicator lamps (shown in a circle in the figure) that indicate the status, water supply time, humidification filter replacement time, indoor cleanliness (clean sign), and cluster status (normal mode / sterilization shower mode) ing.

  FIG. 3 is a side sectional view (longitudinal sectional view) showing the internal structure of the air purifier 1. FIG. 3 (a) shows the case without humidification, and FIG. 3 (b) shows the case with humidification. . In addition, the thick arrow in a figure shows the intake-exhaust path | route of the air cleaner 1. FIG.

  A blower unit 100 for intake and exhaust of room air is provided in the main body 10. The blower unit 100 includes a fan motor 101 that sucks air in the axial direction and exhausts it in the circumferential direction in a unit housing that is shielded from the front surface and the bottom surface and opened at the back surface and the top surface. The intake side of the fan motor 101 is communicated with a rear ventilation path 22 that extends in the vertical direction on the rear side of the blower unit 100 via the rear opening of the unit housing. On the other hand, the exhaust side of the fan motor 101 is communicated with an exhaust air passage 23 that reaches the first air outlet 14a and the second air outlet 14b through the upper surface opening of the unit housing.

  An air cleaning filter unit 16 is detachably provided between the front panel 12 and the blower unit 100 (the front surface of the unit housing). In addition, as the air cleaning filter unit 16, for example, a deodorizing filter that deodorizes intake air using a prefilter, activated carbon, or the like that collects large dust in the intake air in order from the air suction side in a predetermined frame. A unit having a three-layer structure incorporating a dust collection filter that collects fine dust in the intake air can be considered.

  The air that has passed through the air cleaning filter unit 16 flows toward the intake air passage 21 provided below the main body 10 and the humidification unit 17. An air path switching member (damper) 18 is provided in the course of the intake air path 21, and as shown in FIG. 3A, the intake air path 21 is conducted and the inflow air is supplied to the intake air path 21. The airflow is guided directly to the backside air passage 22 or the intake air passage 21 is shielded and the inflowing air is guided to the backside air passage 22 via the humidifying unit 17 as shown in FIG. Can be done.

  The humidifying unit 17 includes a water tank 17a (see FIG. 1), a tray 17b, and a humidifying filter 17c. The water tank 17a is a means for storing water for humidification, and is detachably provided on the side of the main body 10. The tray 17b is a means for storing water supplied from the water tank 17a. The humidifying filter 17c is made of a water-absorbing material having water absorption soaked in the tray 17b, and is formed in a folding screen that is bent zigzag in the front-rear direction. Thereby, the humidification filter 17c sucks up the water in the tray 17b and retains it. Therefore, as shown in FIG. 3B, when the inflowing air is guided to the rear air path 22 via the humidifying unit 17, the water retained in the humidifying filter 17c is taken into the inflowing air that passes through the air. The humidified air flows into the rear air path 22.

  The air cleaning filter unit 16 is mounted in such a manner as to separate the air blowing unit 100 (the front surface of the unit housing) from a predetermined space. By providing such a space, the air that has passed through the air cleaning filter unit 16 can be smoothly flowed toward the intake air passage 21 and the humidification unit 17, so that pressure loss and noise can be reduced. It becomes.

  On the other hand, the exhaust air passage 23 is provided with an ion generator 19 for releasing positive ions and negative ions to sterilize and remove odors in the room or to release only negative ions into the room to obtain a relaxation effect. ing. In this manner, by disposing the ion generator 19 between the first air outlet 14 a and the second air outlet 14 b and the air blowing unit 100, it is possible to prevent the disappearance of ions due to the collision with the air blowing unit 100. . Only the electrode that generates ions may be disposed facing the exhaust air passage 23, and the ion generator 19 itself (power source unit or the like) may be disposed at another position.

  Although not shown in FIGS. 1 and 3, the air cleaner 1 includes a temperature / humidity sensor for detecting indoor temperature and humidity, and a person in front of the device, in addition to the above components. Human body sensor for detecting whether or not, dust sensor for detecting whether or not the amount of dust in the room is larger than a predetermined amount, and odor sensor for detecting whether or not the amount of indoor odor component is larger than a predetermined amount Is provided.

  Next, the electrical system of the air cleaner 1 having the above configuration will be described in detail.

  FIG. 4 is a block diagram showing an electrical connection relationship among the air blowing unit, the operation board, and the control board in the air cleaner 1.

  The blower unit 100 uses the motor voltage Vm (for example, DC 141 [V]) as the operating voltage and the fan motor 101 that is rotationally driven, and the power supply voltage Vcc (for example, DC 15 [V]) as the operating voltage. And a motor control circuit 102 for controlling the driving of the fan motor 101 according to the above. The motor control circuit 102 has not only a drive control function for the fan motor 101 but also a function for detecting the rotational speed of the fan motor 101 (a function for generating a rotational speed signal PG).

  The operation board 200 is a small board on which the switch group and the indicator lamp group of the operation panel 15 are mounted, and is provided directly below the operation panel 15 (see FIG. 3). As described above, by arranging the small operation board 200 separately from the control board 300 which requires a relatively large installation space and has a large arrangement layout restriction, the arrangement layout of the operation panel 15 (and hence the air) The degree of freedom of the total design) of the cleaner 1 can be increased.

  The control board 300 includes an AC / DC conversion circuit 301, a DC / DC conversion circuit 302, a microcomputer 303, a digital / analog conversion circuit 304, a driver circuit 305, and a negative characteristic thermistor (NTC [Negative Temperature Coefficient] thermistor). 306.

  The AC / DC conversion circuit 301 uses a transformer or a full-wave rectifier to convert an AC voltage (AC 100 [V], 50/60 [Hz]) supplied from the commercial power source 400 to a desired DC voltage (for example, DC 141 [V]). ). Note that the DC voltage generated by the AC / DC conversion circuit 301 is supplied to the blower unit 100 (fan motor 101) as the motor voltage Vm described above.

  The DC / DC conversion circuit 302 is means for generating the power supply voltage Vcc described above by stepping down the DC voltage obtained by the AC / DC conversion circuit 301. Further, the DC / DC conversion circuit 302 has not only a function of generating the power supply voltage Vcc but also a function of generating an operating voltage (for example, DC5 [V]) of the operation board 200 and the control board 300 by another system. .

  The microcomputer 303 is means for comprehensively controlling the operation of each part of the air purifier 1. For example, the microcomputer 303 responds to the rotation speed of the fan motor 101 according to the rotation speed signal PG input from the blower unit 100 or the user operation signal input from the operation board 200 (user operation received by the operation panel 15). That is, a PWM [Pulse Width Modulation] signal for controlling the intake / exhaust air volume of the air cleaner 1 is generated. Further, the microcomputer 303 also controls the operation of the air path switching member 18 and the ion generator 19 shown in FIG.

  The digital / analog conversion circuit 304 is means for generating a rotation speed control signal Vs to be supplied to the blower unit 100 by analog-converting the PWM signal input from the microcomputer 303. For example, as the rotation speed control signal Vs, it is conceivable to generate a voltage signal whose voltage level increases as the on-duty of the PWM signal increases, and conversely, decreases as the on-duty of the PWM signal decreases.

  The driver circuit 305 is means for supplying current to the light emitting diodes constituting the indicator lamp group of the operation board 200 in accordance with a control signal from the microcomputer 303. The driver circuit 305 also functions as an electrostatic breakdown protection unit that prevents electrostatic surges from directly propagating to the control signal output port of the microcomputer 303.

  The negative characteristic thermistor 306 is provided on a power supply line from the AC / DC conversion circuit 301 serving as a power supply circuit to the fan motor 101 or the DC / DC conversion circuit 302 serving as a load. The negative characteristic thermistor 306 is a semiconductor formed by sintering a metal oxide such as manganese, cobalt, nickel, and iron, and its resistance value tends to decrease as the temperature increases (so-called negative characteristic). That is, the negative characteristic thermistor 306 shows a high resistance value because the temperature is low immediately after the power is turned on, but when a predetermined time has elapsed since the power is turned on, the temperature rises due to self-heating due to energization and the resistance value decreases. This is a variable impedance element.

  The air purifier 1 according to the present invention (especially its power supply device) is created by paying attention to the above characteristics, and serves as means for suppressing inrush current on the power supply line from the power supply circuit to the load. , And a negative characteristic thermistor 306.

  With such a configuration, when the power supply of the negative characteristic thermistor 306 is low, the inrush current can be effectively suppressed with the maximum resistance value, and in the subsequent normal operation, the current flowing through the load can be suppressed. Since the resistance value of the negative characteristic thermistor 306 varies depending on the magnitude (and thus the temperature), it is possible to keep the heat generation amount constant.

  For example, when the fan motor 101 is operated with the front panel 12 of the air purifier 1 removed, during a light load operation of the blower unit 100, a large current flows through the negative characteristic thermistor 306 and the temperature rises. However, since the resistance value of the negative characteristic thermistor 306 decreases in accordance with this temperature increase, the subsequent temperature increase is suppressed.

  Also, if the negative characteristic thermistor 306 is used as a means for suppressing the inrush current, unlike the conventional structure shown in FIG. 5, it is not necessary to use a control means (transistor or relay) for short-circuiting the resistor R. The factor can be reduced and the cost of the device can be reduced.

  In the above embodiment, the case where the present invention is applied to the power supply device mounted on the air cleaner has been described as an example. However, the application target of the present invention is not limited to this, and other The present invention can also be widely applied to power supply devices mounted on electrical equipment.

  The configuration of the present invention can be variously modified within the scope of the present invention in addition to the above embodiment.

  The power supply device according to the present invention can be used, for example, as a power supply means for an air purifier or an air conditioner that has a filter, collects dust, and sends out ions into the room.

These are perspective views which show the external appearance of the air cleaner 1 which concerns on this invention. FIG. 3 is a front view showing an example of an operation panel 15. These are side surface sectional views (longitudinal sectional views) showing the internal structure of the air purifier 1. These are block diagrams which show the electrical connection relationship of the ventilation unit 100 in the air cleaner 1, the operation board 200, and the control board 300. FIG. These are circuit diagrams which show a prior art example of an inrush current limiting circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air cleaner 10 Main part 11 Base 12 Front panel 13 Side inlet 14a 1st outlet 14b 2nd outlet 15 Operation panel 16 Air purifying filter unit 17 Humidification unit 17a Water tank 17b Tray 17c Humidification filter 18 Air path switching Member (damper)
DESCRIPTION OF SYMBOLS 19 Ion generator 21 Intake air path 22 Back surface ventilation path 23 Exhaust air path 100 Blower unit 101 Fan motor 102 Motor control circuit 200 Operation board 300 Control board 301 AC / DC conversion circuit (AC / DC)
302 DC / DC converter (DC / DC)
303 Microcomputer 304 Digital / Analog Conversion Circuit (D / A)
305 Driver circuit 306 Negative characteristic thermistor 400 Commercial AC power supply

Claims (3)

  A power supply circuit for supplying driving power to a load; and a negative characteristic thermistor provided on a power supply line from the power supply circuit to the load, the resistance value of which decreases with increasing temperature. Power supply.   The power supply device according to claim 1; a fan motor that is driven by using driving power from the power supply device and that sucks and exhausts indoor air; and a filter that collects dust in the indoor air sucked by the fan motor. And an air purifier characterized by comprising:   A fan motor that is rotationally driven using the first DC voltage as an operating voltage and that sucks and exhausts indoor air; and performs drive control of the fan motor according to a rotational speed control signal using the second DC voltage as an operating voltage; A motor control circuit that generates a rotation speed signal indicating the rotation speed of the fan motor; an operation panel that receives a user operation; an AC / DC conversion circuit that converts an AC voltage supplied from a commercial power supply into a first DC voltage; A DC / DC conversion circuit for generating a second DC voltage from the first DC voltage; and a microcomputer for generating a PWM signal for controlling the rotation speed signal and the rotation speed of the fan motor in accordance with the user operation A digital / analog conversion circuit that generates the rotation speed control signal by converting the PWM signal into analog; and the AC / DC conversion circuit A negative thermistor which is provided on a power supply line to the fan motor and the DC / DC converter circuit, and has a resistance value which decreases as the temperature increases; a filter which collects dust of room air taken in by the fan motor; An air cleaner characterized by comprising:

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