JP3119953B2 - DC fan motor with constant air volume control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant-flow-rate control DC fan motor used for a range hood, a ceiling-mounted type ventilation fan, and the like.

[0002]

2. Description of the Related Art In recent years, for a range hood, a ceiling-mounted type ventilating fan, etc., a fan motor having good controllability capable of ventilating at an optimum air flow according to a cooking state or a living room situation has been demanded.

Conventionally, this type of fan motor changes its air volume due to external factors such as the state of a duct, and requires the use of a dedicated sensor called a thermistor to detect the air volume. As the distance becomes longer, there is a problem that dust or the like adheres to the surface of the thermistor and the detection air volume changes. Therefore, we have already proposed methods shown in FIGS.

[0004] As shown in the figure, reference numeral 51 denotes a DC fan motor having a DC motor 52 mounted thereon, and a discharge port 58 thereof is connected to a duct 59. The DC motor 52 guides indoor air contaminated by waste gas generated by cooking through the wall 60 of the building to the outside of the building. The DC motor 52 is rotated by an energization control unit 53 that controls energization to a stator winding according to a rotor position. The rotation speed detecting means 54 detects the rotation speed of the DC motor 52 according to the control state.
The air flow amount instructing means for instructing the operating air amount of the DC motor 52 for realizing each of the strong, medium and weak operating air amounts stores the required number of rotations at each applied voltage to the DC motor 52.
Reference numeral 56 stores the number of rotations for operating the DC fan motor 51 with the air volume indicated by the air volume instructing unit 57 and the air volume instructed from the current applied voltage to the DC motor 52. Is selected from the rotation speed storage means 61, and the selected rotation speed and the rotation speed detection means 5 are selected.
4 compares the current operating rotational speed detected and controls the voltage applied to the DC motor 52 so that the operating rotational speed becomes the same as the selected rotational speed.

In the above configuration, the DC fan motor 51 is operated in advance, and the voltage of the DC motor 52 is continuously changed as shown in FIG. 4 to increase the strength of the DC fan motor 51 at each of the voltages V1, V2, V3,. , Medium, low operating airflow Q
The rotation speeds Nh1, Nh2, Nh3, at h, Qm, Ql,.
, Nm1, Nm2, Nm3,..., And N11, N12, N13,..., And as shown in the table of FIG. In order to operate the motor, the required number of revolutions is stored in the revolution number storage means 61, and the voltage determined in advance by actually installing the DC fan motor 51, Va in FIG. When the operation is started by applying the voltage to the DC motor 52 via the power supply control means 53 by the power supply control means 56, the power supply control means 53 switches the power supply to the winding according to the rotor position of the DC motor 52, and the DC motor 52 At this time, the rotation number detecting means 54 detects the rotation number Na from the switching speed of the current supply to the winding of the current supply control means 53.

Next, when the operating air volume and Qm in the figure are instructed by the air volume instructing means 57, the applied voltage controlling means 56
Searches the rotation speed Nma required for operation at the current applied voltage Va at the indicated airflow Qm from the rotation speed stored in the rotation speed storage means 61, and compares Na with Nma. As a result of the comparison, FIG. 6 and FIG. As shown in FIG. 7, when Na <Nma, the centrifugal blower is used, and as shown in the drawing, it is operated at a flow rate larger than the commanded flow rate Qm. Therefore, it is necessary to reduce the applied voltage. The voltage is reduced by Δva in the figure to make the applied voltage Vb.
In this state, the rotational speed detecting means 54 again detects the rotational speed at the changed applied voltage Vb, Nb in the figure, and the applied voltage control means 56 determines the indicated airflow Qm at Vb from the rotational speed stored in the rotational speed storage means 61. Search for the number of rotations Nmb necessary for operation at and compare Nb with Nmb.

As a result of the comparison, as shown in the figure, Nb> Nmb
In the case of, since the operation is performed with the air volume smaller than the instructed air volume Qm contrary to the case where the operation is performed with the applied voltage Va,
It is necessary to increase the applied voltage, and the applied voltage control means 56 reduces the voltage by Δvb in the figure to make the applied voltage Vc, and the rotation number detecting means 54 again sets the rotation number at the changed applied voltage Vc and Nc in the figure. The detected and applied voltage control means 56 searches the rotational speed Nmc required for operating at the indicated airflow Qm at Vc from the rotational speed stored in the rotational speed storage means 61, and compares Nc with Nmc. As shown in the figure, when Nc <Nmc, it is necessary to reduce the applied voltage because the operation is performed at a flow rate larger than the instructed air flow Qm as in the case of Va, and the applied voltage control means 56 sets the voltage by Δvc in the figure. And the applied voltage is set to VL. At this time, as shown in the figure, the operation is performed with the rotation speed NL at the applied voltage VL and the designated airflow Qm at the applied voltage VL. When the rotation speed becomes equal to the required rotation speed NmL, the DC fan motor 51 is operated at the instructed air volume Qm.
The adjustment voltage for each applied voltage, which holds the air volume Qm while maintaining L, gradually approaches the indicated air volume with Δva>Δvb> Δvc.

FIG. 8 shows an example of a specific circuit of a main part.
The rotation speed detection means 54, the applied voltage control means 56, and the rotation speed storage means 61 are constituted by a microcomputer 62, a switching power supply 63 and peripheral circuits. The energization control means 53 is constituted by a switching element. The current supply to the winding of the DC motor 52 is controlled by the gate signal of the microcomputer 62.

[0009]

SUMMARY OF THE INVENTION Such a conventional DC
The fan motor has a problem that the ROM capacity of the microcomputer is increased because all the specified rotation speeds at each applied voltage at each indicated airflow are increased, resulting in an increase in cost.

The present invention has been made to solve the above-mentioned problems, and does not need to memorize all the specified rotation speeds at each applied voltage at each indicated airflow, without being affected by external factors such as the external wind pressure and the state of the duct.
It is an object of the present invention to provide a DC fan motor for a ventilator , which can be operated at a constant airflow without receiving the airflow .

[0011]

Means for Solving the Problems A constant air flow control D according to the present invention.
In order to achieve the above object, the C fan motor includes a DC fan motor equipped with a DC motor, energization control means for controlling energization of the DC motor, and an operation speed of the DC motor based on the operation of the energization control means. Means for detecting the number of revolutions to be detected, air volume instructing means for instructing the operating air volume of the DC fan motor, and instructing a specified number of revolutions at a voltage applied to the DC motor for operating at the air volume instructed by the air volume instructing means A specified rotation speed calculating means for calculating from the air volume and the applied voltage, wherein the DC fan is configured such that the operating rotation speed detected by the rotation speed detecting device is the same as the specified rotation speed determined by the specified rotation speed calculating device. A DC fan motor having a constant air volume control for a ventilator, which is provided with an applied voltage control means for controlling an applied voltage of the motor.

[0012]

According to the present invention, the specified rotation speed at the voltage applied to the DC motor for operating at the indicated airflow by the specified rotation speed calculation means can be obtained by the calculation from the indicated airflow and the applied voltage. it can.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, reference numeral 1 denotes a DC fan motor on which a DC motor 2 is mounted, and a discharge port 8 thereof is connected to a duct 9. The DC motor 2 is a duct that guides indoor air contaminated by waste gas generated by cooking through the building wall 10 to the outside of the building. The DC motor 2 is rotated by energization control means 3 that controls energization to the stator windings according to the rotor position. The rotation speed detection means 4 detects the rotation speed of the DC motor 2 according to the control state.
Air flow instructing means for instructing the operation air flow of the DC fan motor 1 such as medium or low, and 5 is a specification for calculating a specified rotation speed at a voltage applied to the DC motor 2 for realizing the strong, medium and weak operation air flow. The rotation speed calculation means 6 is an applied voltage V of the DC motor 2 detected by the rotation speed detection means 4.
A changed applied voltage difference klV (n) is obtained from a difference klN (n) between the operating rotation speed in (n) and the specified rotation speed calculated by the specified rotation speed calculating means 5, and the voltage V (n + 1) to be applied next is obtained. ) Is determined and an applied voltage control means for sending a signal to the energization control means 3. The specified rotation number calculating means 5 obtains the specified rotation number by the following method.

First, the output P (W) and the torque T (kgcm) of the DC motor are expressed by the following equations.

[0016]

(Equation 1)

[0017]

(Equation 2)

Here, N is the number of rotations of the motor (rpm),
I indicates the current (A) and Kt indicates the torque constant, and the following equation is obtained from (Equation 1) and (Equation 2).

[0019]

(Equation 3)

The following relation is known for the similarity rule in general fluids.

[0021]

(Equation 4)

[0022]

(Equation 5)

[0023]

(Equation 6)

[0024] Here, L is the shaft power of the fan (W), Q is flow rate (m ³ / min), Ps is the static pressure (mmAq), N _F is the fan speed (rpm), D is the impeller Diameter (mm), K _L is the shaft power coefficient, K _Q is the air flow coefficient, K _P is the static pressure coefficient, and (Equation 4) can be replaced by (Equation 5) and (Equation 6) as follows: it can.

[0025]

(Equation 7)

[0026] Then, the fan and motor rotational speed N and the shaft power L of the fan since it is directly connected is considered to be equal to the rotational speed N and the output P of the motor, (Equation 3) and (7)
Gives the following equation:

[0027]

(Equation 8)

If the applied voltage to the motor is V (V), the total resistance of the armature circuit is R (Ω), and the induced voltage constant is Ke, the circuit equation and the induced voltage E (V ) Is shown by the following equation.

[0029]

(Equation 9)

[0030]

(Equation 10)

Then, (Equation 8), (Equation 9) and (Equation 1)
0), the following equation can be obtained.

[0032]

[Equation 11]

Here, the static pressure coefficient Kp, the diameter D of the impeller, the torque constant Kt, the total resistance R of the armature circuit, and the induced voltage constant K
Since e is a constant determined when the specifications of the fan motor are determined, the specified number of revolutions can be calculated from the indicated airflow Q and the voltage V applied to the motor, and other configurations are the same as those of the conventional example. It is.

In the above configuration, when the power supply of the DC fan motor 1 is turned on, the operation is started according to the procedure of the program shown in the flowchart of FIG. 2 stored in the ROM of the microcomputer 11. First, at step 14, the initial voltage is output. At the same time, an initial gate signal is output in step 15 to rotate the DC motor 2, and then in step 16, the rotor position of the DC motor 2 is detected, and a gate signal corresponding to the detected position is output in step 17. After the change time of the gate signal is measured in step 18, the operation speed is calculated and held in step 19 from this change time, and the flow rate instruction signal is taken in step 20 to check the indicated flow rate. Based on (Equation 11), a specified rotation speed that matches the commanded air volume and the applied voltage is calculated, and The operation speed held in step 9 is compared with the operation speed in step 22. If the result of the comparison is that the speed is the same, the process returns to step 16, and the operation is continued by repeating this operation. If the rotation speed is different from the specified rotation speed, the difference between the operation rotation speed and the specified rotation speed is calculated in step 23, the output voltage of the switching power supply 12 is determined and output in step 24, and the process returns to step 16; Continued.

As described above, according to the DC fan motor having the constant air volume control according to the embodiment of the present invention, by providing the prescribed rotational speed computing means 5 for calculating the prescribed rotational speed by calculation, it is possible to cope with each indicated air volume and each applied voltage. Since it is not necessary to store the specified rotation speed, the ROM capacity of the microcomputer can be reduced.

[0036]

As is clear from the above description of the embodiment, according to the present invention, by providing the specified rotation speed calculating means for calculating the specified rotation speed from the indicated airflow and the voltage applied to the DC motor, Since it is not necessary to measure and store the specified rotation speed corresponding to the indicated air volume and each applied voltage, the development cost is reduced and the microcomputer ROM capacity can be reduced.
Since a cheaper microcomputer can be used, low-cost, high-precision constant airflow control for the indicated airflow can be achieved.
Can be done, duct length, duct bend, outside wind
Of pressure, oil fumes and dust inside the filter / duct
Without depending on cooking conditions and living room conditions
Ventilation device that can realize a ventilation device that can ventilate with the optimal air volume
It is possible to provide a DC fan motor for controlling the fixed air flow.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a DC fan motor with constant air volume control according to the present invention.

FIG. 2 is a flowchart showing an example of a program for the operation.

FIG. 3 is a configuration diagram of a conventional fan motor.

FIG. 4 is a static pressure-air flow graph showing the same operation characteristics.

FIG. 5 is a table showing a relationship among the indicated airflow, applied voltage, and rotation speed.

FIG. 6 is a graph showing the relationship between the applied voltage and the number of rotations.

FIG. 7 is a graph showing the relationship between the operating airflow, static pressure, and rotation speed.

FIG. 8 is a circuit diagram of the main part.

FIG. 9 is a flowchart illustrating an example of a program for the same operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC fan motor 2 DC motor 3 Energization control means 4 Revolution number detection means 5 Specified revolution number calculation means 6 Applied voltage control means 7 Air volume indication means

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-4788 (JP, A) JP-A-62-152389 (JP, A)

Claims (1)

(57) [Claims] 1. A DC fan motor having a DC motor mounted thereon, energization control means for controlling energization of the DC motor, and rotation speed detection means for detecting an operation speed of the DC motor based on an operation of the energization control means. An air flow rate instructing means for instructing an operation air volume of the DC fan motor, and a specified rotation speed at an applied voltage to the DC motor for operating at the air volume instructed by the air volume instructing means is calculated from the instructed air volume and the applied voltage. And a control unit for controlling a voltage applied to the DC fan motor so that an operation speed detected by the rotation speed detection unit is the same as a specified rotation speed obtained by the specified rotation speed calculation unit. A constant air flow control DC fan motor for a ventilator , comprising an applied voltage control means.