JP2002349478A - Fan motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fan motor controller capable of securing a desired air quantity even when an installing state is different. SOLUTION: This fan motor controller comprises a static pressure determining means 26 for determining which zone of a plurality of previously divided static pressure zones is to be applied, based on a difference between a first motor output value obtained by operating a DC motor at a preset first rotation speed and a second motor output value obtained by operating the DC motor at a preset second rotation speed, when a fan is driven by the DC motor and the rotation speed of the DC motor is controlled so as to provide a desired air quantity, and a rotation speed determining means 28 for determining a rotation speed of the DC motor based on the desired air quantity and the static pressure zone determined by the static pressure determining means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan motor control device for driving a range hood or a ceiling-mounted fan with a DC motor and controlling the rotation speed of the DC motor so as to obtain a target air volume.

[0002]

2. Description of the Related Art Induction motors are often used in range hoods and ceiling-mounted fans. But,
The rotation speed of the induction motor changes depending on the state of the duct, for example, an external factor such as a static pressure, and the air flow also changes accordingly. To solve this problem, set the fan
In addition to being driven by a C motor, the DC motor has been driven at a constant rotational speed by performing feedback control.

[0003]

As described above, in a fan driven at a constant rotation speed by a DC motor, the rotation speed is kept constant even when an external factor, for example, the static pressure of the hood changes. However, since the rotation speed was determined assuming that the static pressure was constant, the air volume was insufficient in the installation state with high static pressure, and the air volume was too large in the installation state with low static pressure, and the noise also increased. There were issues that had to be addressed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a fan motor control device capable of securing a desired air flow even when installation conditions are different.

[0005]

According to a first aspect of the present invention, there is provided a fan motor control apparatus which drives a fan with a DC motor and controls the number of rotations of the DC motor so as to obtain a target air volume. Between a first motor output value obtained by operating the DC motor at the first rotation speed and a second motor output value obtained by operating the DC motor at a second predetermined rotation speed. A static pressure determining means for determining which of a plurality of static pressure zones are divided in advance based on the difference; and a DC motor based on the target airflow and the static pressure zone determined by the static pressure determining means. Rotation speed determining means for determining the rotation speed.

According to a second aspect of the present invention, in the fan motor control device according to the first aspect, the static pressure determination means obtains a motor output value at a point in time when a predetermined time has elapsed since the operation of the DC motor was started. It is characterized by the following. According to a third aspect of the present invention, in the fan motor control device according to the second aspect, the static pressure determination means obtains the motor output value a plurality of times, averages the obtained motor output values, and performs static based on the average value. The pressure zone is determined.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a block diagram showing a schematic configuration of a fan motor control device according to the present invention. In the figure, a power supply circuit 21 rectifies and smoothes an AC and outputs a predetermined DC voltage.
1 is connected to a DC input terminal of a switching circuit 22 formed by three-phase bridge connection of six switching elements each having a diode connected in anti-parallel. A DC motor 23 for driving a fan is connected to an AC output terminal of the switching circuit 22. In order to control on / off of the switching element of the switching circuit 22,
Driving means 24 generally called a driver is provided.

A motor output detecting means 25 for detecting an output value based on a current supplied to the DC motor 23.
And a static pressure for determining which of a plurality of pre-divided static pressure zones belongs to, based on the output of the motor output detecting means 25 when a predetermined rotational speed command is applied to the driving means 24. Determination means 26; on the other hand,
An air flow rate setting means 27 is provided for the user to set the air flow rate of the fan, and a rotation speed determination means 28 determines a predetermined rotation speed according to the set air flow rate and the static pressure zone determined by the static pressure determination means 26. It is configured to apply a command to the driving means 24.

The general operation of the fan motor control device configured as described above will be described. First, the static pressure determination unit 26 applies a first rotation speed command set in advance to the driving unit 24. The driving means 24 controls the switching elements of the switching circuit 22 to be turned on and off in response to the rotation speed command, and
The C motor 23 is controlled to a rotation speed corresponding to the rotation speed command. The motor output detection means 25 calculates the motor output value at this time, that is, the first motor output value, and stores it. Subsequently, the static pressure determining unit 26 applies a preset second rotational speed command to the driving unit 24. Drive means 24
Controls ON / OFF of the switching element of the switching circuit 22 in response to the rotation speed command to control the DC motor 23 to a rotation speed corresponding to the rotation speed command. The motor output detection means 25 calculates the motor output value at this time, that is, the second motor output value and stores it. Further, the static pressure determining means 26 determines the static pressure zone of the fan air passage based on the difference between the first motor output value and the second motor output value.

Thereafter, the rotation speed determining means 28 determines the fan rotation speed in accordance with the set air volume and the static pressure determined by the static pressure determining device 26 so that the air volume set by the air volume setting device 27 is obtained. , To the driving means 24. The drive means 24 controls the switching circuit 22 according to the rotation speed command. By the above operation, a desired air volume can be ensured even when the static pressure changes. FIG. 2 shows a specific embodiment of the present invention, in which a DC motor driven fan to which the present invention is applied is mounted. It is sectional drawing which shows schematic structure of a hood. In FIG. 1, a range hood fan 1 has a box-like shape in which a lower portion extends in an eave shape toward the front, and a fan casing 3 and a fan device 4 are provided in a hood body 2 having a suction port 5 formed on a lower surface thereof. It is arranged and configured. Also, inside the hood body 2,
A grease filter 6 for capturing oils and fats from the ventilation air is provided so as to partition between the suction port 5 and the fan casing 3. An outdoor discharge duct 7 connected to the outer wall of the building is connected to the discharge port 2a at the top of the hood body 2.

As a result, when the fan device 4 is driven, the kitchen is mainly equipped with a microwave oven (not shown).
The air in the upper part is sucked through a suction port 5 located directly above the air outlet, and the air is discharged through an outdoor discharge duct 7 to the outside through a grease filter 6, thereby ventilating the kitchen. ing. An exhaust duct 9 for discharging oil smoke, combustion gas, and the like generated in the roaster chamber of the range is connected to a lower surface of the hood body 2 close to the wall portion 8. Note that the range hood fan 1 can adjust the ventilation air volume to five levels of air volume 1, air volume 2, air volume 3, air volume 4, and air volume 5.

FIG. 3 shows a specific configuration example of a control circuit for controlling the number of revolutions of the DC motor 10 constituting the fan device 4. In FIG. 1, a DC motor 10 is a motor control IC.
15 are built in. This motor control IC
Reference numeral 15 denotes a switching circuit 17 including a transistor for turning on and off the energization of the motor winding portion 10a and D
A position detection circuit 14 composed of a Hall element for detecting a rotation position of a rotor (not shown) of the C motor 10 is provided. By controlling the switching circuit 17 on and off based on the detection state of the position detection circuit 14, The DC motor 10 is rotated. In this case, the negative sides of the motor control IC 15 and the switching circuit 17 are connected to each other, and are grounded via the current detection resistor 16. Therefore, the current consumed by the DC motor 10 and the motor control IC 15 passes through the current detection resistor 16, so that the entire current consumption and the motor output value can be detected by detecting the voltage generated by the current detection resistor 16. Can be.

On the other hand, a switching power supply 12 connected to an AC power supply 11 converts AC to DC and outputs the DC power. The switching power supply 12 supplies a predetermined voltage Vm to the DC motor 10 and
The drive voltage Vcc is supplied to the motor control IC 15. And the microcomputer 13
According to the set value of the air volume setting device 18 for setting the air volume in five stages, the rotation speed of the DC motor 10 is determined so as to obtain the air volume, and the motor control I / O is controlled so as to obtain the rotation speed.
A switching frequency command PG is added to C15, and a predetermined voltage Vm is supplied from the switching power supply 12 in accordance with the command.
Are turned on and off in accordance with the switching frequency command PG and applied to the DC motor 10. The microcomputer 13 detects the overall power consumption and the output value of the DC motor 10 by detecting the voltage of the current detection resistor 16 through the switching power supply 12.

Here, when the installation condition of the range hood fan 1 is changed, the load of the fan device 4 fluctuates.
Even when the DC motor 10 is rotated at the set number of revolutions, the displacement of the fan device 4 varies. That is, as the length of the outdoor discharge duct 7 becomes longer or the inner diameter of the outdoor discharge duct 7 becomes smaller, the load of the fan device 4 increases and the exhaust air volume of the fan device 4 decreases. In addition, as the airtightness of the room to which the fan device 4 is attached is higher, the load on the fan device 4 is increased, and the exhaust air volume of the fan device 4 is reduced.

According to the present invention, in response to the change in the mounting state of the fan device 4, even if the static pressure changes, the number of revolutions at which the air volume set by the air volume setting device 18 is obtained is determined. The feedback control is performed so as to obtain the rotation speed. Hereinafter, the operation including the static pressure determination process by the microcomputer 13 will be described.

Generally, when the rotation speed of the fan device 4 is kept constant, the air volume increases as the static pressure Ps decreases, and decreases as the static pressure Ps increases. Also,
When the fan device 4 is driven so that the air volume becomes equal between the case where the static pressure is high and the case where the static pressure is low, the motor output value when the static pressure is high is small and the motor output value when the static pressure is low is large. Become.

As a result of repeating various experiments on the characteristics of the fan device 4, characteristics as shown in FIG. 4 were obtained. This means that the variation range of the static pressure is A, B, C, D, E (A
>B>C>D> E), and in order to obtain, for example, the maximum airflow 5 corresponding to each zone, 1200 rpm in the A zone, 1100 rpm in the B zone, and C 980r in the zone
This was achieved by driving the fan device 4 at 870 rpm in the D zone and 780 rpm in the E zone. If the minimum air volume is to be set to 1, the A zone has 580 rpm, the B zone has 580 rpm, the C zone has 500 rpm,
It suffices to drive the fan device 4 at 420 rpm in the D zone and 340 rpm in the E zone.

On the other hand, in the five zones A, B, C, D and E, for example, the motor output value when the fan device 4 is driven at 780 rpm and the motor output value when the fan device 4 is driven at 980 rpm When calculating the difference from the value,
As shown in FIG. 5, the difference in the A zone is the smallest,
It was found that the difference in the E zone was the largest, and in each of the zones A to E, the difference was gradually increased. FIG. 5 shows 90V, 95V, 1 in consideration of the case where the power supply voltage fluctuates.
The same experiment as described above was repeated for 00 V, 105 V, and 110 V, and a similar difference appeared at any power supply voltage.

In this embodiment, four threshold values F for determining the static pressure are based on the case where the power supply voltage is 100 V.
-OUT1, F-OUT2, F-OUT3, F-OUT4 (F-OUT1 <F-OUT2
<F-OUT3 <F-OUT4) is set to determine the static pressure zone.

FIG. 6 shows such a static pressure determination.
In the table stored in the microcomputer 13 (see FIG. 3), the microcomputer 13
At 0 rpm, the DC motor 10 is drive-controlled to determine the motor output value at that time, and then, at the second time, at 980 rpm
To control the drive of the DC motor 10 to obtain the motor output value at that time. Next, the microcomputer 13 calculates the difference between the two motor output values, searches the table in FIG. 6 to determine which zone of the static pressure is A, B, C, D, or E. As shown in FIG. 4, the microcomputer 13 determines the rotation speed in accordance with the static pressure zone obtained by the determination and the air volume set externally, and the microcomputer 13 controls the position detection circuit 14 so as to obtain this rotation speed. And performs feedback control.

The measurement of the motor output value (motor input) for the determination of the static pressure is performed at a stage when a certain time has elapsed since the power was turned on and the operation state was stabilized.
The calculation accuracy of the motor output value is improved by employing the average value of the values obtained over a plurality of times.

FIG. 7 is a flowchart showing a specific processing procedure of the microcomputer 13 for determining the static pressure and determining the rotation speed. In this case, step 101
It is determined whether or not the fan motor (DC motor) has been operated, and if it has been operated, it is determined in step 102 whether or not the static pressure zone has been determined.
At 03, the value of the counter for counting the number of operations of the motor output value is incremented by “1”, and subsequently, at step 104, it is determined whether or not the value is “1”.

If it is determined that the value is "1", then in step 105, the rotation speed (7
80 rpm), and a predetermined time T
After confirming that 1 has elapsed, the motor output value is integrated in step 107, and it is determined in step 108 whether or not the integrated number has reached a predetermined number n.
The average value of the integrated value is obtained and stored.

Next, in step 110, it is determined whether or not the average value has become two. If the average value has not become two, the process returns to step 103, and the counter is incremented. Check that the value is "2". Subsequently, the operation is performed at the rotation speed (980 rpm) of the air flow rate 4 in the A zone, and
Step 110 is repeated. As a result, two motor output values are obtained. Therefore, in step 113, the static pressure zone is determined using the table shown in FIG.
At step 114, the value of the counter is cleared to "0".

Next, at step 115, using the table shown in FIG. 4, a rotation speed according to the static pressure determined according to the above-described procedure and the air volume set externally is selected, and the rotation speed is selected. Is given to the motor control IC 15.

Thus, according to the present embodiment, since the static pressure can be accurately determined from the relationship between the difference between the motor output values at each of the two rotational speeds obtained through the experiment and the static pressure, the static pressure can be determined. A desired air volume can be secured against the change of the air flow. In addition, the problem that noise increases at a low static pressure is also solved.

In the above-described embodiment, the thresholds F-OUT1, F-OUT1 for determining the static pressure are premised on the assumption that the power supply voltage is usually 100 V, and in some cases, may be lower than this.
OUT2, F-OUT3 and F-OUT4 are set, but the power supply voltage is 11
When the voltage is 0 V, an appropriate threshold may be set from the characteristic diagram of FIG.

In the above-described embodiment, the motor output values are obtained at two rotation speeds at which the difference between the motor output values is considered to be large from the relationship between the air volume and the static pressure.
The motor output values may be calculated at other rotation speeds.

Furthermore, in the above-described embodiment, the description has been given of a fan device used in a range hood. However, the present invention is not limited to this, and a ceiling embedded type fan or the like may be replaced by a DC motor. The present invention can be applied to a driving device.

[0030]

As is apparent from the above description, according to the present invention, it is possible to provide a fan motor control device capable of securing a desired air flow even when installation conditions are different.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a fan motor control device according to the present invention.

FIG. 2 is a cross-sectional view showing a schematic configuration of a hood equipped with a DC motor driven fan to which the present invention is applied as a specific embodiment of the present invention.

FIG. 3 is a circuit diagram showing a specific configuration of a control circuit that controls the number of rotations of a DC motor of the fan device shown in FIG. 2;

FIG. 4 is a chart for determining a rotation speed based on a static pressure zone and a flow rate.

FIG. 5 is a diagram showing a relationship between a voltage difference between a motor output value at two rotation speeds and a voltage using static pressure as a parameter.

FIG. 6 is a chart showing a relationship between a difference between motor output values and a static pressure zone.

FIG. 7 is a flowchart showing a specific processing procedure of static pressure determination and rotation speed determination by the microcomputer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Range hood fan 2 Hood main body 4 Fan device 10 DC motor 12 Switching power supply 13 Microcomputer 14 Position detection circuit 15 Motor control IC 17 Switching circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hibashi Anfuku 336 Tatehara, Fuji-shi, Shizuoka Toshiba Carrier Co., Ltd. (72) Yoshihiro Yamada 336 Tatehara, Fuji-shi, Shizuoka Toshiba Carrier Engineering Co., Ltd. F term (reference) 3H021 AA01 AA08 BA06 CA02 CA07 CA10 DA06 EA09 EA12 3H045 AA06 AA09 AA12 AA26 AA31 BA12 CA02 CA21 CA25 CA28 DA07 DA45 EA35 EA38 5H560 AA01 BB04 BB07 DA02 DC12 EB01 TT04 SS07

Claims (3)

[Claims] 1. A fan motor control device for driving a fan with a DC motor and controlling the number of rotations of the DC motor so as to obtain a target air volume, wherein the DC motor is operated at a preset first number of rotations. A first motor output value obtained by
A static pressure determining means for determining which of a plurality of static pressure zones are divided in advance based on a difference from a second motor output value obtained by operating the DC motor at the number of rotations; A fan motor control device comprising: rotation speed determining means for determining the rotation speed of the DC motor based on the target air flow and the static pressure zone determined by the static pressure determination means. 2. The fan motor control device according to claim 1, wherein said static pressure determination means obtains a motor output value when a predetermined time has elapsed since the operation of said DC motor was started. 3. The static pressure determining means determines a motor output value a plurality of times, averages the obtained motor output values, and determines the static pressure zone based on the average value. 3. The fan motor control device according to 1.