JP2009013890A - Power source circuit for fan and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power source device for a fan reducing electric power consumption without deteriorating cooling effect. <P>SOLUTION: The power source device for the fan is provided with a switch 2 turning electric power supply to the fan 4 on and off. Off-time of the switch corresponds to a point of time when rotation speed of the fan drops to a predetermined value after the switch is transfer from on to off. Consequently, electric power consumption is reduced without deteriorating cooling effect. When a plurality of fans are provided, points of time when the switches controlling electric power supply to the plurality of fans are mutually shifted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply circuit for a cooling fan and a control method thereof.

  An example of a general circuit configuration of the cooling fan will be described with reference to FIG. In FIG. 12, when the power is turned on, the cooling fans 4-1 to 4-3 are rotated at a constant rotational speed because a constant voltage is applied. The cooling fan is rotated using a power source used by the device or a voltage (internal power supply voltage) used inside the device. For this reason, while the device is operating, the cooling fan is energized and consumes power.

  Depending on the small-scale equipment, the temperature rise inside the equipment may be detected, and the fan may be controlled to turn on / off based on the detection result. However, in a large-scale system device, the temperature is detected individually. , It is difficult and economical to turn on / off the fan. For this reason, in the configuration of FIG. 12, the plurality of fans 4-1, 4-2 and 4-3 are always operated as a unit to cool the entire apparatus.

  As the scale of the device increases, the power consumption of the fan increases due to an increase in the size of the fans and an increase in the number of installed fans. Therefore, low power consumption is strongly desired.

  On the other hand, the performance of fan motors has improved dramatically due to advances in processing / manufacturing technology of motor bearings (bearings), and the rotation is extremely smooth. For example, as shown in FIG. 6, even if the power of the fan is turned off, the fan continues to rotate for a while due to the inertial force.

  As a related technique of the present invention, Patent Document 1 discloses a configuration for preventing the bias magnetism of a pulse transformer in a push-pull converter.

  Patent Document 2 discloses that an electric floor heating device that keeps the heat generation of a PTC heater substantially constant at a constant temperature and does not require a large rated amperage such as a switch is turned on / off by an electric signal from a temperature sensor. A configuration is disclosed in which an anti-phase voltage that is off and half-wave rectified is applied to each PTC heater.

  In Patent Document 3, the timing at which switching elements that supply current to each of a plurality of motors are turned on is shifted by phase conversion means to reduce fluctuations in the power supply voltage of the motor drive means due to current flowing into all the motors at once. A configuration of a motor control device that suppresses generation of noise is disclosed.

  In Patent Document 4, a first fan motor (radiator fan motor) and a second fan motor (capacitor fan motor) are connected in parallel between the drain of a semiconductor switching element (FET) and ground, and the source of the FET Is connected to the positive electrode of the battery via an ignition switch, a pressure switch and a water temperature switch are connected in series between the gate of the FET and the ground, and the gate of the FET is connected to the output terminal of the PWM control circuit for PWM control A configuration is disclosed in which a magnet clutch relay is connected between the input terminal of the circuit and the ground so that the rotational speed of the fan can be finely controlled.

  As a control device for a cooling fan motor such as a CPU, in Patent Document 5, as shown in FIG. 14, a switching element 22 is provided in a power supply line of a DC fan motor 21, and the switching element 22 is controlled by a PWM signal. A configuration in which on / off control is performed via an element 24 is disclosed (FIG. 8 of Patent Document 5). In FIG. 14, 25 is a circuit resistance, 26 is a base resistance, and 23 is a capacitor. When the PWM signal is HIGH, the control element (NPN transistor) 24 is turned on, the base of the switching element 22 (PNP transistor) is pulled to the ground potential side, the switching element 22 is turned on, and the power supply Vcc to the DC fan motor 21. When power is supplied and the PWM signal is LOW, the NPN transistor 24 is turned off and the switching element 22 is turned off.

JP 2004-015900 A JP 2005-042979 A JP-A 62-002892 JP 09-272322 A JP 2003-319677 A

  The cooling fan circuit configuration shown in FIG. 12 has the following problems.

Since the fan is always energized, power consumption increases. Further, as the scale of the device increases, the number of fans increases, and a large-capacity power source is required for the fans. Further, since the fan is rotated regardless of the state of the device, there may be an excessive cooling effect.

  Accordingly, an object of the present invention is to provide an apparatus and a method for reducing power consumption while avoiding a decrease in cooling effect.

  Another object of the present invention is to provide an apparatus and a method that can achieve the above-mentioned object and can control the power consumption and the cooling effect to the most efficient state.

  In order to solve the above-described problems, the invention disclosed in the present application is generally configured as follows.

  A fan power supply device according to one aspect of the present invention includes a switch for turning on / off power supply to a fan. In the present invention, the on / off control of this switch is devised. The switch off time corresponds to a point in time when the rotational speed of the fan falls to a predetermined value after the switch transitions from on to off, and the switch on time is from the switch off to on. This corresponds to the time point when the stable rotational speed of the fan is reached after the transition to.

  A fan power supply device according to another aspect of the present invention includes a plurality of switches that respectively turn on and off power supply to a plurality of fans, and a control circuit that performs control to shift the times when the plurality of switches are turned on from each other. I have.

  In the fan power supply device according to still another aspect of the present invention, power is supplied to the first and second fans through the first and second rectifying elements on the secondary side of the transformer, with the time shifted from each other. .

In the present invention, a first switch inserted between one end of the primary winding of the transformer and a negative electrode of a DC power source having a positive electrode connected to a center tap of the primary winding of the transformer;
A second switch inserted between the other end of the primary winding of the transformer and the negative electrode of the DC power supply, and the first fan is connected to one end of the secondary winding of the transformer. The second fan is inserted between a second terminal of the first rectifying element to which one terminal is connected and a half tap of the transformer, and the second fan includes a half tap of the transformer and a secondary winding of the transformer. It is good also as a structure inserted between the 1st terminal of the said 2nd rectifier with which the 2nd terminal was connected to one end of.

  In the present invention, the transformer is a commercial transformer in which a commercial power source is connected to a primary winding side, and the first fan has the first terminal connected to one end of a secondary winding of the transformer. The second fan is connected between the second terminal of the first rectifying element and the other end of the secondary winding, and the second fan has a second terminal connected to one end of the secondary winding of the transformer. It is good also as a structure connected between the 1st terminal of this rectifier, and the other end of the said secondary winding.

  A power supply device for a fan according to another aspect of the present invention includes a switch for turning on / off power supply to the fan, a detection circuit that detects a predetermined state of the device, and a detection result in the detection circuit. And a control circuit that controls a period during which the switch is turned on or turned off.

  According to one aspect of the present invention, a switch is provided in a power supply line of a fan, and the switch OFF time is set to a predetermined value in which the rotational speed of the fan is predetermined after the switch transitions from ON to OFF. The on-time of the switch is set in correspondence with the time when the stable rotational speed of the fan is reached after the switch transitions from off to on.

  In the method according to another aspect of the present invention, the plurality of switches that respectively turn on and off the power supply to the plurality of fans are controlled to shift the time when the plurality of switches are turned on from each other.

  In the method according to another aspect of the present invention, the first and second fans are energized with the time shifted from each other via the first and second rectifying elements on the secondary side of the transformer.

A method according to yet another aspect of the present invention detects a predetermined condition for an apparatus,
Based on the detection result, a period for turning on or turning off a switch provided in the power supply line of the fan is controlled.

  ADVANTAGE OF THE INVENTION According to this invention, in the apparatus provided with the several cooling fan, the power consumption of a fan can be reduced, without reducing a cooling effect. According to the present invention, there is provided an apparatus that makes it possible to control power consumption and a cooling effect to the most efficient state.

  Several embodiments of the present invention will be described below with reference to the accompanying drawings.

<Example 1>
FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. In the present embodiment, the power consumption of the fan 4 can be reduced by turning on and off the switch 2 inserted in the power supply line of the cooling fan 4 (fan motor) to obtain a pulsed applied voltage. For the sake of simplicity, FIG. 1 shows a configuration in which one fan is used. In FIG. 1, a fan (FM) 4 includes a fan, a motor, and a motor drive circuit (the same applies to other drawings).

  In FIG. 1, a DC power source 1 is a power source for driving a fan 4, and power is supplied from the DC power source 1 to the fan 4 when the switch 2 is on. FIG. 1 does not show a control circuit for controlling on / off of the switch 2. In FIG. 1, a DC power source 1 is used and the fan 4 is configured by, for example, a DC motor (DC brushless motor, stepping motor, or the like), but may be an AC power source and an AC drive fan. As described above, with the progress of bearing processing / manufacturing technology, the fan performance is dramatically improved and the rotation is smooth. As shown in FIG. 6, even if the power supply of the fan 4 in the operating state is turned off, the fan rotates for a while due to inertial force. By utilizing this characteristic and turning on / off the power supply of the fan at high speed, the power consumption can be reduced without significantly reducing the rotational speed of the fan.

  In the configuration shown in FIG. 1, the capacitor 3 may be provided in parallel with the fan 4 as in the configuration shown in FIG. 14. When the switch 2 is on, the capacitor 3 is charged. When the switch 2 is turned off, the fan 4 is supplied with voltage / current from the capacitor 3 and can increase the rotation time.

  In the present embodiment, the control is performed so that the switch 2 is off for a long time until the rotation speed of the fan 4 is reduced by turning the power on and off so that the cooling effect is not affected. As a result, power consumption can be reduced.

  Further, in the present embodiment, the on time of the switch 2 is set to be narrowed until the time when the fan 4 reaches the stable rotational speed, so that the power consumption can be reduced. FIG. 7 is a diagram for explaining the operation of this embodiment.

In FIG.
(A) is a voltage waveform applied to the fan 4;
(B) is a waveform of a current flowing through the fan 4;
(C) shows the rotation speed of the fan 4.

  As the switch 2 is turned on / off, the rotational speed of the fan 4 fluctuates as shown in FIG. As can be seen from FIG. 7, the power consumption can be reduced by adjusting the ON / OFF time ratio to such an extent that the cooling effect is not affected.

  For example, the power consumption W of the fan 4 is an effective value of voltage (a) × effective value of current (b). When the duty ratio D = 0.5, the following calculation is performed. The duty ratio is the ratio of the on period in one cycle of the switching operation.

Effective value of voltage (a) = Vp × √D;
RMS value of voltage (b) = Ip × √D;
電力 Power consumption W = (Vp × √D) × (Ip × √D)
= 0.5 x Vp x Ip

  That is, half the power is required compared to the case where voltage is continuously supplied from the power source to the fan.

  As described above, the present embodiment provides the following operational effects.

  With a simple configuration that switches the power supply line of the fan 4, it is possible to reduce power consumption without impairing the cooling effect as compared with the continuous voltage application method.

  Moreover, the cooling capacity can be freely adjusted by adjusting the switching time ratio.

  In this embodiment, the present invention can be applied to any DC motor, but can also be applied to an AC motor such as a three-phase AC.

<Example 2>
A second embodiment of the present invention will be described. The basic configuration is the same as that of the first embodiment, but a device is devised for controlling a plurality of fans. FIG. 2 is a diagram showing the configuration of the second exemplary embodiment of the present invention. Although not particularly limited, in this embodiment, three fans are used.

In FIG. 2, the on / off control circuit 6 individually controls on / off of the switches 5-1, 5-2, and 5-3. For example, if the current consumption per fan is 0.5A and 3 fans are used in parallel,
0.5A x 3 pieces = 1.5A
Current consumption. The supply capacity of the DC power source 1 is required to have a rating of 1.5 A or more.

  In this embodiment, the voltages V1 to V3 applied to the fans 5-1 to 5-3, respectively, as shown in FIG. By shifting the phase so that they do not overlap, the rated current of the DC power source 1 that is the power source of the three fans 4-1, 4-2, 4-3 is 0, which is the current consumption of one fan. .5A is possible. In this embodiment, the rated current of the DC power supply 1 can be lowered by shifting the phase so that the ON times of a plurality of fans do not overlap, and a small power supply can be used, and the fan power circuit is small and inexpensive. Can be configured.

<Example 3>
Next, a third embodiment of the present invention will be described. In this embodiment, the voltage line applied to the fan is not directly switched, but a power supply pulse is generated using a transformer and supplied to the fan. As shown in FIG. 13, a voltage used in an electronic device may be converted into a fan voltage by a switching power supply (switching regulator). That is, FIG. 13 shows a configuration in which a fan is driven using a typical switching power supply (push-pull, center tap rectification method) as a comparative example.

  In FIG. 13, when the switch (NPN transistor) 7-1 is turned on, the switch (NPN transistor) 7-2 is turned off. At this time, the positive electrode of the DC power source 1 → the center tap P2 of the transformer (pulse transformer) 8 → A current flows from the primary winding M1 → P1 → the switch 7-1 → the negative electrode of the DC power source 1, and a voltage having P4 as positive and P5 as negative is induced in the secondary winding H1, and this voltage (V4 ), The current flows as follows: diode 9-1 → smoothing circuit 16 (comprising choke coil 14 and capacitor 15) → parallelly connected fans (fan motors) 4-1, 4-2 → P5. On the other hand, when the switch 7-2 is turned on, the switch 7-1 is turned off. At this time, the positive electrode of the DC power source 1 → the center tap P2 of the transformer 8 → the primary winding M2 → P3 → the switch 7-2 → DC. A current flows to the negative electrode of the power supply 1, and a voltage having P6 as positive and P5 as negative is induced in the secondary winding H2, and this voltage causes the current to be connected in a diode 9-2 → smoothing circuit 16 → in parallel. The fans (fan motors) 4-1 and 4-2 flow to P5. The fans 4-1 and 4-2 are energized simultaneously.

  FIG. 3 is a diagram showing the configuration of the third exemplary embodiment of the present invention. In FIG. 3, when the switch 7-1 is turned on, the switch 7-2 is turned off. At this time, the positive electrode of the DC power source 1 → the center tap P2 of the transformer 8 → the primary winding M1 → P1 → the switch 7-1. → Current flows to the negative electrode of the DC power source 1, and a voltage with P4 being positive and P5 being negative is induced in the secondary winding H1, and this voltage causes the current to be diode 9-1 → fan (fan motor) It flows from 4-1 to P5. That is, when the switch 7-1 is on, the fan (fan motor) 4-1 is energized.

  When the switch 7-2 is turned on, the switch 7-1 is turned off. At this time, the positive electrode of the DC power source 1 → the center tap P2 of the transformer 8 → the primary winding M2 → P3 → the switch 7-2 → DC power source 1 A current flows to the negative electrode of the inverter, and a voltage having P4 negative and P5 positive is induced in the secondary winding H1, and this voltage causes the current to be P5 → fan (fan motor) 4-2 → diode 9−. 2 → P4 flows. That is, when the switch 7-2 is on, the fan (fan motor) 4-2 is energized.

  Also in this embodiment, it is possible to reduce power consumption by applying a pulse voltage to the fan. Further, the smoothing circuit 16 in FIG. 13 can be eliminated, and the power supply unit can be simplified.

  The primary side of the transformer 8 in FIGS. 3 and 13 is a basic configuration of a push-pull converter, and the switches (NPN type bipolar transistors) 7-1 and 7-2 are signals that are 180 ° out of phase alternately. The base is driven.

  In FIG. 3, the voltages V4 and V5 applied to the fans 4-1 and 4-2 are as shown in FIG. The voltages V4 and V5 applied to the fans 4-1 and 4-2 are 180 degrees out of phase, and the fans 4-1 and 4-2 are supplied with power alternately. Therefore, this embodiment also has the same effect as the second embodiment.

  Since the configuration of the push-pull converter shown in FIG. 13 and the like is known, detailed description thereof is omitted. In the present embodiment, the same effect can be obtained with any system other than the push-pull converter as long as it is an arbitrary circuit system that can apply a rectangular wave voltage to the fan.

<Example 4>
As still another embodiment of the present invention, the method is basically the same as the method using the transformer of the above embodiment, but an example using a commercial transformer will be described as the simplest circuit configuration.

  FIG. 4 is a diagram showing the configuration of the fourth exemplary embodiment of the present invention. As shown in FIG. 4, in this embodiment, the voltage is stepped down by using a commercial transformer 11 (50 Hz / 60 Hz) with the commercial power supply 10 as input, half-wave rectified by diodes 9-1 and 9-2, and the fan 4-1. , 4-2 are fed alternately. As shown in FIG. 10, half-wave rectified voltages V6 and V7 that are 180 degrees out of phase are applied to the fans 4-1 and 4-2, respectively. It is possible to reduce power consumption and simplify the power supply unit for the fan. However, since the frequency is low and it is a sine wave, the fan rotational speed fluctuation increases, but if there is no problem with the cooling effect, this is a practical technique.

<Example 5>
Furthermore, as another embodiment of the present invention, in the basic configuration of FIG. 1, information on the state of the device, for example, information such as internal temperature and current consumption is detected, and the on / off time of the switch 2 is adjusted in real time. This makes it possible to create optimal cooling conditions. FIG. 5 is a diagram showing the configuration of the fifth exemplary embodiment of the present invention. A detection circuit 12 that detects the state of the device is provided, and an on / off control circuit 13 that controls on / off of the switch 2 based on the detection result of the detection circuit 12 is provided. In the fifth embodiment, the on / off time is arbitrarily varied, and can be applied to the on / off control of the switch in each of the above-described embodiments.

  FIG. 11 is a flowchart for explaining the operation of the fifth embodiment of the present invention. The operation of this embodiment will be described with reference to the flowchart of FIG.

  In general, the required cooling conditions in the equipment vary depending on environmental conditions and operating conditions. For example, the internal temperature increases or decreases due to environmental changes, or when a certain circuit operates, the current consumption increases rapidly.

  The state in the device is monitored by the detection circuit 12 (step S1 in FIG. 13), and after the state is detected (step S2 in FIG. 13), it is compared with the current cooling capacity and determined (step S3 in FIG. 13). ).

  If the determination result indicates that further cooling capacity is required, the on / off control circuit 13 sets the on time of the switch 2 longer (steps S4 and S5 in FIG. 13).

  On the other hand, if the cooling capacity is excessive based on the determination result, the on / off control circuit 13 sets the on time of the switch 2 to be short (steps S6 and S7 in FIG. 13).

  If the result of determination is appropriate, the current cooling capacity is maintained.

  As described above, the optimum cooling condition is set (step S8 in FIG. 13), and the process of detecting the state of the device is repeated (step S9 in FIG. 13), so that the optimum cooling effect considering low power consumption is achieved. Can always be maintained.

  Although the on / off control circuit 13 has been described by adjusting the ON time of the switch 2, the cooling effect can also be adjusted by adjusting the OFF time.

  The present invention can be applied to all electronic devices that require a forced air cooling system using a fan.

  It should be noted that the disclosures of the above patent documents are incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiments and examples can be changed and adjusted based on the basic technical concept. Various combinations and selections of various disclosed elements are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea.

It is a figure which shows the structure of the 1st Example of this invention. It is a figure which shows the structure of the 2nd Example of this invention. It is a figure which shows the structure of the 3rd Example of this invention. It is a figure which shows the structure of the 4th Example of this invention. It is a figure which shows the structure of the 5th Example of this invention. It is a figure explaining transition of the rotation speed of the fan at the time of OFF. FIG. 4 is a timing waveform diagram for explaining the operation of the first exemplary embodiment of the present invention. It is a timing waveform diagram for demonstrating operation | movement of the 2nd Example of this invention. It is a timing waveform diagram for demonstrating operation | movement of the 3rd Example of this invention. It is a timing waveform diagram for demonstrating operation | movement of the 4th Example of this invention. It is a flowchart for demonstrating the procedure of the 5th Example of this invention. It is a figure which shows the structure of related technology. It is a figure which shows the structure of a comparative example. It is a figure which shows the structure of related technology (patent document 5).

Explanation of symbols

1 Power supply (DC power supply)
2 Switch 3 Capacitor 4, 4-1, 4-2, 4-3 Fan (FM)
5-1, 5-2, 5-3, 7-1, 7-2 Switch 6, 13 ON / OFF control circuit 8 Transformer 9-1, 9-2 Diode 10 Commercial power supply 11 Commercial transformer 12 Detection circuit 14 Choke coil 15 capacitor 16 smoothing circuit
21 DC fan motor 22 Switching element 23 Capacitor 24 Control element 25, 26 Resistance

Claims (10)

With a switch to turn on / off the power supply to the fan,
The switch off time corresponds to the time when the rotational speed of the fan falls to a predetermined value after the switch transitions from on to off,
The on-time of the switch corresponds to a point in time when the stable rotational speed of the fan is reached after the switch is switched from off to on. With multiple switches that turn on and off the power supply to multiple fans,
A power supply device for a fan, comprising a control circuit for performing a control for shifting times for turning on the plurality of switches.   A power supply pulse is generated using a transformer, and power is supplied to the first and second fans through the first and second rectifying elements on the secondary side of the transformer at different times. A power supply device for fans. A first switch inserted between one end of the primary winding of the transformer and a negative electrode of a DC power source having a positive electrode connected to a center tap of the primary winding of the transformer;
A second switch inserted between the other end of the primary winding of the transformer and the negative electrode of the DC power source;
With
The first fan is inserted between a second terminal of the first rectifier element having a first terminal connected to one end of a secondary winding of the transformer and a half tap of the transformer.
The second fan is inserted between a half tap of the transformer and a first terminal of the second rectifying element having a second terminal connected to one end of a secondary winding of the transformer. The fan power supply device according to claim 3. The transformer comprises a commercial transformer that inputs commercial power to the primary side,
The first fan is connected between a second terminal of the first rectifying element having a first terminal connected to one end of a secondary winding of the transformer and the other end of the secondary winding,
The second fan is connected between a first terminal of a second rectifying element having a second terminal connected to one end of the secondary winding of the transformer and the other end of the secondary winding. The fan power supply device according to claim 3. A switch to turn on / off the power supply to the fan,
A detection circuit for detecting a predetermined state with respect to the device;
A fan power supply apparatus comprising: a control circuit that controls a period during which the switch is turned on or a period during which the switch is turned off based on a detection result of the detection circuit. A switch is provided on the power supply line of the fan, and the off time of the switch is set corresponding to the time when the rotation speed of the fan falls to a predetermined value after the switch transitions from on to off,
An on-time of the switch is set in correspondence with a point in time when the stable rotation speed of the fan is reached after the switch is switched from off to on. For multiple switches that turn on / off power supply to multiple fans,
A fan power supply control method, wherein control is performed to shift the times when the plurality of switches are turned on from each other.   A power supply pulse is generated using a transformer, and the first and second fans are energized at different times through the first and second rectifying elements on the secondary side of the pulse transformer. Control method for fan power supply. Detects predefined conditions for the device,
A fan power supply control method, comprising: controlling a period during which a switch provided in a power supply line of a fan is turned on or off based on the detection result.

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