JP3362826B2 - Fan motor control device - Google Patents

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 controlling the rotation of a fan, and more particularly to a fan motor control device for appropriately controlling the rotation according to the state of a blower flow path blown by a fan motor.

[0002]

2. Description of the Related Art Conventionally, as a means for detecting the current on the motor side and controlling the rotation of a fan motor, a motor and a resistor are connected in series, the voltage of the resistor is detected, and the voltage is fed back to rotate. Thus, there is one that detects the current flowing through the motor and feeds it back to control the rotation.

Further, as a conventional motor control device used for controlling a fan, as disclosed in, for example, Japanese Patent Application Laid-Open No. 4-36508, a wind speed sensor or the like is installed in an air flow passage, and detection from this wind speed sensor or the like is performed. In some cases, the number of rotations of the fan motor is controlled according to the signal.

[0004]

Although there is a fan motor control device of this kind in the related art, when the power supply voltage of the fan motor control device of the related art changes, the detection output also changes, so that sufficient detection cannot be performed. could not. Further, in the case of providing a power supply to the detection circuit by disposing a power supply circuit between the drive power supply of the motor and the detection circuit, there is a problem that the entire circuit becomes large in size and naturally becomes large and expensive.

In some cases, a motor using a variable voltage switching power source is used for controlling the motor. When the variable voltage switching power source is used, the variable voltage switching power source is expensive, large in size and heavy in weight. Therefore, it tends to hinder cost reduction and weight reduction of the entire apparatus.

Besides, it is conceivable to use a so-called PWM type motor drive IC for rotating the motor by switching the DC power obtained by rectifying and smoothing the AC power and supplying it as drive power to the motor. In this case, since the DC power obtained by rectifying and smoothing the AC power is supplied to the motor drive IC, the voltage fluctuation of the commercial power supply generally used as the AC power is large, and therefore the current flowing to the motor side must be accurately known. As a result, when the motor is used as a fan motor, it becomes more difficult to accurately calculate the air flow path resistance in which the fan is installed.

That is, since the rotation speed of the motor, the current flowing through the motor, and the flow resistance of the air flow passage have a constant relationship with each other, it is possible to detect the rotation speed of the motor and the current flowing through the motor. For example, the flow path resistance can be calculated, but even if the motor rotation speed and flow path resistance do not change, the current changes due to fluctuations in the AC voltage. Cannot be calculated.

The present invention has been proposed in view of the above points, and can reduce the cost and the weight of the power source,
Moreover, the current flowing through the fan motor side can be accurately grasped,
Therefore, it is an object of the present invention to provide a fan motor control device that can accurately determine the flow path resistance.

Further, the present invention provides a fan motor control device capable of always maintaining an appropriate motor rotation speed according to the flow passage resistance of the air flow passage without installing an air flow rate detecting device or the like in the air flow passage. Is its purpose.

[0010]

In order to achieve the above object, the invention according to claim 1 provides a fan motor control device for controlling the rotation of a fan motor for blowing air, wherein information on a drive voltage on the fan motor side is provided. Voltage detecting means for detecting, current detecting means for detecting information about the drive current on the fan motor side, and current for correcting and converting the current information detected by the current detecting means based on the voltage information detected by the voltage detecting means. A calculation means, a rotation speed detection means for detecting the rotation speed of the fan motor, and an air flow passage for the fan motor to blow air based on the current information obtained by the current calculation means and the rotation speed detected by the rotation speed detection means. Flow path resistance determining means for determining the flow path resistance of the fan motor, and rotation control of the fan motor based on the flow path resistance determined by the flow path resistance determining means. And wherein the door.

According to the first aspect of the present invention, based on the voltage detected by the voltage detecting means, for example, a current that may flow at a predetermined voltage (AC100V as an example, or a voltage corresponding thereto) is calculated as the current calculating means. Converts the current detected by the current detecting means. Then, based on the converted detection current and the rotation speed detected by the rotation speed detection means, the flow path resistance determination means determines the flow path resistance of the blower flow path, and the fan motor is rotationally controlled according to the flow path resistance. To do.

According to a second aspect of the present invention, in a fan motor control device for controlling the rotation of a fan motor for air blowing arranged in an air flow passage, a rectifying / smoothing means for rectifying and smoothing AC power and outputting DC power. , Power control means for supplying DC power from the rectifying / smoothing means to the fan motor as drive power, rotation speed detection means for detecting the rotation speed of the fan motor, and information about drive voltage on the fan motor side Voltage detection means, current detection means for detecting information about the drive current on the fan motor side, and current information detected by the current detection means based on the voltage information detected by the voltage detection means to the motor side. Current calculation means for converting into current information that will flow when the voltage of the above is applied, the current calculated by the current calculation means, and the rotation Flow path resistance determining means for determining the flow path resistance of the air flow path based on the number of revolutions detected by the detecting means, and optimum air flow rate determining means for determining the optimum air flow rate based on the combustion amount of the combustor. And the optimum rotation speed of the fan motor based on the optimum air flow rate determined by the optimum air flow rate determination means and the flow path resistance determined by the flow path resistance determination means. It is characterized in that the rotation is controlled so that becomes the optimum rotation speed.

According to a second aspect of the present invention, based on the voltage detected by the voltage detecting means, a predetermined voltage (for example, AC100
The current calculation means converts the current detected by the current detection means into a current that will flow when V (or a voltage corresponding thereto). Then, the flow path resistance determination means determines the flow path resistance of the blower flow path based on the converted detection current and the rotation speed detected by the rotation speed detection means. Further, the optimum air flow rate determination means determines the optimum air flow rate based on the combustion amount of the combustor, and controls the rotation of the fan motor based on the optimum air flow rate and the determined flow path resistance.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a hot water supply apparatus provided with a motor control device of the present invention, in which a burner 2 and a heat exchanger 3 are arranged inside a casing 1 of the hot water supply apparatus. A sirocco fan 6 driven by a fan motor 5 is installed inside a fan case 4 continuous to the lower side of the casing 1, and an exhaust port 7 is formed in the upper part of the casing 1.

A fuel supply pipe 8 for supplying a fuel such as gas or oil is connected to the burner 2, and a water supply pipe 10 for supplying water is connected to the heat exchanger 3. . A valve 1 is provided on the fuel supply pipe 8 and the water supply pipe 10.
1 and 12 are interposed, and these valves 11 and 12 are controlled by a hot water supply control unit 13.

The motor control device includes a rectifying / smoothing means 16 for rectifying and smoothing AC power from a commercial power supply 15 of 100 VAC, and outputting DC power, and a DC power from the rectifying / smoothing means 16 based on a control pulse. A power control means 17 for switching the fan motor 5 to supply it to the fan motor 5 as driving power, a rotation speed detection means 18 for detecting the rotation speed of the fan motor 5, and a current detection means 19 for detecting the output current of the rectifying / smoothing means 16. The rotation of the fan motor 5 is based on the voltage detection means 28 for detecting the output voltage of the rectifying / smoothing means 16, the rotation speed command signal, the rotation speed detected by the rotation speed detection means 18, and the current flowing through the fan motor 5. Detected by the duty ratio control means 20 for controlling the duty ratio of the control pulse so that the number becomes the command rotation speed, and the current detection means 19. Output current and voltage detecting means 28
Detection voltage, current detection means 19 and voltage detection means 28
The current calculation means 21 for calculating the current flowing through the fan motor 5, the optimum air flow rate determination means 22 for determining the optimum air flow rate based on the combustion charge of the burner 2, and the current calculation means. Flow path resistance determining means 23 for determining the flow path resistance of the air flow path constituted by the fan case 4 and the casing 1 based on the current calculated by 21 and the rotation speed detected by the rotation speed detecting means 18, The optimum rotation speed of the fan motor 5 is determined based on the optimum air flow rate determined by the optimum air flow rate determination means 22 and the flow path resistance determined by the flow path resistance determination means 23, and the fan motor 5
Of the combustion speed based on the flow path resistance determined by the flow path resistance determination means 23 and the optimum rotation speed determination means 24 that supplies a rotation speed command signal to the duty ratio control means 20 so that the rotation speed of the above is the optimum rotation speed. Abnormality determination means 25 for determining abnormality
And an abnormality processing unit 26 that outputs a stop signal to the hot water supply control unit 13 to stop the combustion of the burner 2 when the abnormality determination unit 25 determines that the combustion is abnormal.

It should be noted that the duty ratio control means 20, the current calculation means 21, the optimum air flow rate determination means 22, the flow path resistance determination means 23, the optimum rotation speed determination means 24, the abnormality determination means 25, and the abnormality processing. The means 26 is realized by the microcomputer 27. The microcomputer 27 controls the entire combustion device.

FIG. 2 is a circuit block diagram of the drive unit of the fan motor 5, which is mainly a motor drive IC 3
It is composed of 1. This motor drive IC31 is
It is equipped with terminals 31a to 31e, and is equipped with a power control means 17 and a rotation speed detection means 18.

The power control means 17 includes a motor driver 32 for supplying drive power to each coil of the fan motor 5,
A PWM variable speed circuit 33 that switches the drive power supplied to the fan motor 5 by the motor driver 32 is provided. The rotation speed detecting means 18 is the fan motor 5
A rotation logic 35 that calculates the rotation speed of the fan motor 5 based on a detection signal from a Hall IC 34 that includes a plurality of Hall elements built in, and a rotation speed pulse corresponding to the rotation speed calculated by the rotation logic 35 are generated. And a rotation speed pulse generation circuit 36 that operates.

The drive power from the rectifying / smoothing means 16 is input to the terminal 31a, and the drive power is supplied to the power control means 17.
Is supplied to the motor driver 32. The DC power from the auxiliary power supply 37 is input to the terminal 31b, and this DC power is supplied to each part of the motor drive IC 31 as a power supply. A control voltage is input from the duty ratio control means 20 to the terminal 31c, and this control voltage is supplied to the power control means 17
Is supplied to the PWM variable speed circuit 33. From the terminal 31d, a rotation speed pulse is output from the rotation speed pulse generation circuit 36 of the rotation speed detection means 18, and this rotation speed pulse is supplied to the duty ratio control means 20. The terminal 31e is
It is a ground terminal.

The rectifying / smoothing means 16 is realized by a full-wave rectifier composed of, for example, a diode bridge and a smoothing circuit composed of a capacitor, and rectifies and smoothes AC power obtained from a commercial power supply 15 of 100 V, for example. Output power. The power control means 17 is based on the control pulse whose duty ratio is controlled according to the control voltage from the duty ratio control means 20, and based on the control pulse, the rectification smoothing means 1
The DC power from 6 is switched to the fan motor 5
To drive power to.

That is, the DC drive power supplied to the fan motor 5 is PWM-controlled by the power control means 17. The rotation speed detection means 18 is based on a detection signal from a rotation detection sensor composed of a Hall IC 34 including a plurality of Hall elements built in the fan motor 5, based on the detection signal.
The rotation speed pulse of the fan motor 5 is detected, the rotation speed pulse corresponding to the detected rotation speed is supplied to the duty ratio control means 20, and the rotation signal corresponding to the rotation of the rotation element of the fan motor 5 is supplied to the power control means 1.
Supply to 7.

The current detecting means 19 is provided with a current detecting element 29 such as a resistor or a current transformer, and detects the output current of the rectifying / smoothing means 16. Voltage detecting means 28
Detects the output voltage of the rectifying / smoothing means 16. The duty ratio control means 20 adjusts the control voltage so that the rotation speed of the fan motor 5 becomes the command rotation speed, and supplies the control voltage to the power control means 17.

The fan motor 5 is a three-phase brushless motor, more specifically a permanent magnet type synchronous motor,
In the present embodiment, it is used to drive the sirocco fan 6 of the combustion device.

FIG. 3 is a circuit block diagram of the power control means 17, which includes a triangular wave oscillation circuit 41, a comparator 42, a three-phase distribution circuit 43, and transistors TR1 to TR6. ing. It should be noted that components not directly related to the present invention, such as a diode for protecting the transistors TR1 to TR6 and a circuit for detecting and protecting overcurrent flowing in the coils 5a to 5c of the fan motor 5, are illustrated and described. Is omitted.

The triangular wave oscillation circuit 41 is, for example, 20 KHz.
Outputs a triangular wave with a period of. The comparator 42 is composed of an operational amplifier, and has a triangular wave voltage from the triangular wave oscillation circuit 41 and a control voltage Vs from the duty ratio control means 20.
When the control voltage Vs is equal to or higher than the triangular wave voltage, the control voltage Vs is turned on, and when the control voltage Vs is lower than the triangular wave voltage, the control voltage Vs is turned off and a control pulse having a cycle of 20 KHz is output.

That is, the duty ratio of the control pulse changes according to the control voltage Vs from the duty ratio control means 20. The three-phase distribution circuit 43 is responsive to the rotation signal from the rotation speed detection means 18 to form the upper transistor T.
One of R1 to TR3 and the lower transistor T
One of R4 to TR6 is selectively turned on.
For example, when the transistors TR1 and TR5 are on,
A drive current flows from the coil 5a of the fan motor 5 to the coil 5b.

That is, the rotation of the fan motor 5 is continued by sequentially switching the coils 5a to 5c for flowing the current and the direction of the current according to the rotational position of the rotor of the fan motor 5. Further, the three-phase distribution circuit 43 turns on / off the transistor to be turned on among the transistors TR4 to TR6 on the lower stage side according to the control pulse from the comparator 42. That is, the three-phase distribution circuit 43 performs PWM control of the drive power supplied to the fan motor 5 according to the control voltage Vs from the duty ratio control means 20.

The operation of the power control means 17 will be briefly described. The AC power from the commercial power supply 15 is rectified and smoothed by the rectifying / smoothing means 16 and supplied to the fan motor 5 as driving power via the power control means 17. At this time, the power control means 17 performs PWM control, and controls the drive voltage to the fan motor 5 so that the rotation speed of the fan motor 5 becomes the command rotation speed.

Now, as shown in FIG. 4, the maximum voltage of the triangular wave from the triangular wave oscillator circuit 41 is Vh, the minimum voltage is V1, and the control voltage from the duty ratio control means 20 is Vs.
Then, as shown in FIG. 5, the control pulse output from the comparator 42 turns on when the control voltage Vs is equal to or higher than the triangular wave voltage, and turns off when the control voltage Vs is lower than the triangular wave voltage. The pulse train has the same cycle as.

Since the three-phase distribution circuit 43 applies the control pulse from the comparator 42 to the base of the transistor to be turned on among the transistors TR4 to TR6 on the lower side, the drive power of the fan motor 5 is controlled by the control pulse. Is switched by and the drive power corresponding to the duty ratio of the control pulse is supplied to the fan motor 5.

Next, the operation of the fan motor control device of the present invention specifically used for a hot water supply device will be described with reference to the flow chart shown in FIG. When an operation command is input to the controller from a remote controller (not shown), the hot water supply controller 13 controls the valves 11, 12 and an igniter (not shown) to start the ignition operation.
A signal corresponding to the combustion amount of the burner 2, that is, the valve opening amount of the valve 11 is output to the optimum air flow rate determination means 22. As a result, the optimum air flow rate determination means 22 calculates the optimum air flow rate according to the combustion amount of the burner 2 based on the signal from the hot water supply control unit 13 (step S1).

At this time, the fan motor 5 is not rotating and the determination result by the flow path resistance determining means 23 is not supplied to the optimum air flow rate determining means 22. Therefore, the optimum rotation speed determining means 24 is set to a preset value, for example. A rotation speed command signal corresponding to an initial rotation speed of about 3000 rpm is output to the duty ratio control means 20 (step S2). As a result, the duty ratio control means 20 supplies the electric power control means 17 with the control voltage Vs with which the fan motor 5 rotates at the initial rotation speed. As a result, the power control means 17 causes the PWM
The drive power is controlled by the method to drive the fan motor 5 so as to rotate at the initial rotation speed.

Next, the abnormality determining means 25 activates the built-in timer (step S3).

Next, the current detecting means 19 detects the current flowing through the fan motor and the voltage detecting means 28 detects the supply voltage (step S4). The rotation speed detection means 18 detects the rotation speed of the fan motor 5 based on the detection signal from the Hall IC 34 of the fan motor 5 (step S5).

Next, the current calculation means 21 calculates the current flowing through the fan motor 5 for properly obtaining the flow path resistance from the output current of the rectifying / smoothing means 16 detected by the current detection means 19 (step S6). .

That is, if there is no voltage fluctuation of the commercial power supply 15 and the output voltage of the rectifying / smoothing means 16 is always constant,
Although it is not necessary to correct the output current of the rectifying / smoothing means 16 detected by the current detecting means 19, in reality, for example, in the case of the commercial power supply 15 of 100 VAC, it varies from 75 to 120 volt. The current calculation means 21 calculates the fan motor 5 from the output current of the rectifying / smoothing means 16.
It is necessary to correct the output current of the rectifying / smoothing means 16 which is actually detected by calculating and correcting the current flowing through the side. Here, in order to make the explanation more understandable, first, in the case where it is not necessary to correct the output current of the rectifying / smoothing means 16,
The flow path resistance determination operation will be described.

That is, regarding the relationship between the rotation speed N of the fan motor 5 and the current I flowing through the fan motor 5, as shown in FIG. 7, data on the relationship with the flow path resistance should be stored in a memory or the like in advance. Thus, the flow path resistance Φ can be determined from the rotation speed N and the current I. For example, if the current I becomes I0 when the rotation speed N is N1, or the current I becomes I1 when the rotation speed N is N2, it can be determined that the flow path resistance Φ is Φ1, and the rotation speed N is If the current I becomes I0 at N0, it can be determined that the flow path resistance Φ is Φ0.

Φ0 is smaller than Φ1. Further, the flow path resistance Φ can be experimentally obtained by the following mathematical formula 1, where N is the number of rotations of the fan motor 5 and I is the current flowing through the fan motor 5. However, g (N), f
(N) is a function of the rotation speed N. Alternatively, as another empirical formula, it is obtained by the following mathematical formula 2.

[0040]

[Equation 1]

[0041]

[Equation 2]

Next, the operation of the current calculation means 21 for correcting the current detected by the current detection means 19 will be described. As long as a constant voltage is always supplied from the commercial power supply 15, the flow path resistance can be determined by the above method, but in reality, the voltage of the commercial power supply 15 fluctuates, so it can be determined only by the above method. Instead, correction by the current calculation means 21 becomes necessary.

That is, when the voltage of the commercial power supply 15 fluctuates, the relationship between the rotation speed N of the flow path resistance Φ and the current I shown in FIG. 7 fluctuates, for example, as shown in FIG. In this case, a method may be considered in which the voltage fluctuation of the commercial power supply 15 is taken into consideration in advance and the relational data indicating the flow path resistance shown in FIG. 7 is stored for each voltage value of the commercial power supply. However, in this case, since a very large memory capacity is required, the relational data of the flow path resistance as the reference as shown in FIG. 7 is stored and the current corresponding to the case where the detected current is used as the reference is set as the current. The correction can reduce the memory, and the same effect can be obtained.

Next, the correction performed by the current calculation means 21 will be described in detail. The value of the output voltage of the rectifying / smoothing means 16 detected by the voltage detecting means 28 is V0, and the value of the output current of the rectifying / smoothing means 16 detected by the current detecting means is I0. Further, the voltage when the data showing the relationship with the flow path resistance held in the memory as shown in FIG. 7 is obtained is the voltage V (in this embodiment, the voltage when AC100V), and when the voltage is V, Let I be the corresponding correction current.

From the standpoint of the amount of work of the fan motor 5, if the electrical / mechanical work conversion efficiency is considered to be 100%, the following formula 3 is established.

(3) I × V = I0 × V0

Therefore, the correction current that will flow when the AC100V commercial current is supplied can be obtained by the following equation (4).

[Equation 4]

Thus, in step S6, the current I flowing through the fan motor 5 is calculated by the current calculating means 21 to correct the output current I0 detected by the current detecting means 19, and in step S7. Since the flow path resistance is calculated by the flow path resistance determining means 23 using the current I, the flow path resistance can be accurately obtained regardless of the voltage fluctuation of the commercial power supply 15.

Then, the flow path resistance judging means 23 detects the current and rotation speed detecting means 18 corrected by the current calculating means 21.
The flow path resistance Φ of the fan flow path in the fan motor 4 and the casing 1 is determined based on the relationship from FIG.

Next, the abnormality determining means 25 determines whether the flow path resistance Φ determined by the flow path resistance determining means 23 is between a predetermined lower limit value ΦL and upper limit value ΦH. Yes (step S8). That is, when the flow path resistance Φ is outside the range between the lower limit value ΦL and the upper limit value ΦH, it is not possible to secure an appropriate air flow rate even if the rotation speed of the fan motor 5 is controlled. Must be
If the flow path resistance Φ is between the lower limit value ΦL and the upper limit value ΦH, it is possible to determine a normal state because it is possible to secure an appropriate air flow rate by controlling the rotation speed of the fan motor 5. The first quadrant of FIG. 7 represents the relationship among the current I flowing through the fan motor 5, the rotation speed N, and the flow path resistance Φ.
The fourth quadrant represents the relationship among the rotation speed N of the fan motor 5, the air flow rate Q, and the flow path resistance Φ.

If the flow path resistance Φ is between the lower limit value ΦL and the upper limit value ΦH, the abnormality determining means 25 determines that it is normal and clears the built-in timer (step S).
9). As soon as this timer is cleared, it restarts and restarts the timing operation.

Next, the optimum rotation speed determination means 24 determines the optimum rotation speed based on the flow path resistance Φ determined by the flow path resistance determination means 23 and the optimum air flow rate determined by the optimum air flow determination means 22. It calculates (sweep S10) and outputs a rotation speed command signal to the duty ratio control means 20. That is, as shown in FIG. 7, since the relationship between the rotation speed N of the fan motor 5 and the air flow rate Q changes depending on the flow path resistance Φ,
The optimum rotation speed is determined according to the flow path resistance Φ so that the optimum air flow rate can be obtained. This optimum rotation speed Ns is obtained by, for example, an empirical formula (5) below, where Q0 is the optimum air flow rate and Ng is the reference rotation speed determined based on the reference flow path resistance Φ0 and the combustion amount. Alternatively, as another empirical formula, it can be obtained by the following mathematical formula 6.

[0052]

[Equation 5]

[0053]

[Equation 6]

As a result, the duty ratio control means 20
However, based on the rotation speed command signal corresponding to the optimum rotation speed calculated by the optimum rotation speed determination means 24 and the actual rotation speed from the rotation speed detection means 18, the fan motor 5 becomes the optimum rotation speed. The control voltage Vs is output to the power control means 17 (step S11).

As a result, the electric power control means 17 switches the DC electric power supplied to the fan motor 5 based on the control voltage from the duty ratio control means 20, and drives the fan motor 5 to reach the optimum rotation speed. .

Next, the optimum air flow rate determination means 22 determines whether or not the combustion amount is changed based on the signal from the hot water supply control unit 13 (step S12). If there is no change, the microcomputer 27 determines It is determined whether or not an operation end instruction has been input from the remote controller (step S13), and if not input, the processing returns to step S5. If entered, the routine ends.

In step S12, if the optimum air flow rate determination means 22 determines that the combustion amount has changed, the process returns to step S1.

In step S8, the abnormality determining means 25
However, if it is determined that the flow path resistance Φ is not between the predetermined lower limit ΦL and upper limit ΦH, the abnormality determining means 25 further determines whether or not the built-in timer has timed out ( If the time is not up in step S14), the process proceeds to step S10. If the time is up,
It outputs to the abnormality processing means 26 that there is an abnormality. That is, since the flow path resistance Φ may constantly change due to the influence of wind or the like, the flow path resistance Φ is determined to be in an abnormal state only when the flow path resistance Φ reaches an abnormal value for a predetermined period of time.

Next, when the abnormality processing means 26 receives the signal indicating the abnormality from the abnormality determining means 25, it outputs a stop signal to the hot water supply control section 13 to stop the combustion of the burner 2 or the like. Error processing (step S1
5), the routine ends.

As described above, the rectifying / smoothing means 16 for rectifying and smoothing the AC power to output the DC power, and the DC power from the rectifying / smoothing means 16 are switched based on the control pulse to drive the fan motor 5 as driving power. Power supply control means 17, rotation speed detection means 18 for detecting the rotation speed of the fan motor 5, current detection means 19 for detecting the output current of the rectifying and smoothing means 16, rotation speed command signal and rotation speed detection means 18. On the basis of the output current detected by the current detection means 19 and information on the voltage detected by the voltage detection means 28 based on the rotation speed detected by
Since the current calculation means 21 for calculating the current flowing through the fan motor 5 when the predetermined voltage is applied is provided, the current flowing through the fan motor 5 can be accurately known regardless of the voltage fluctuation of the commercial power supply 15. Therefore, it becomes possible to properly judge the flow path resistance.

In the above embodiment, the detection position of the current detecting means 19 is arranged at the output position of the rectifying / smoothing means 16, but it is not limited to this position, but the power control means 17 and the motor 5 are not limited to this position. It may be provided between them or may be arranged on the ground side of the motor 5. Further, if possible, it is not necessary to consider the power consumption of the power control means 17, so it is also a desirable detection method to directly detect before and after the motor 5. Further, any other position may be used as long as it can detect the information about the current.

Further, in the above embodiment, the detection position of the voltage detecting means 28 is arranged at the output position of the rectifying / smoothing means 16, but it is not limited to this position, but the commercial power source 1
The voltage of 5 may be monitored. Any other position may be used as long as it can detect the voltage-related information.
However, when the detection position by the current detection unit 19 and the detection position by the voltage detection unit 28 are set to different positions, the above formula (2) is not always applied as it is, but there is a fixed relationship due to the work amount. Since this holds, the current correction can be realized by a calculation formula or a relationship based on experimental values.

Further, in the above embodiment, in the flow chart shown in FIG. 6, the process returns to step S5 when it is not finished in step S13, but it may return to step S4. In this case, the operations of steps S4 to S15 are performed when the power supply 15 fluctuates even when the air flow rate is not changed.

In the above embodiment, the PWM type fan motor control device has been mainly described, but it is applicable to both the PAM type fan motor control device and the other type fan motor control device. Of course.

In the PWM method, more accurate calculation can be performed if the current amount of the drive IC 31 and the like is taken into consideration.

Further, in the above-described embodiment, an example of correcting and calculating the current detected by the current detecting means 19 by the current calculating means 21 in the formula (4) is shown, but this is merely an example. . It goes without saying that other correction calculations may be used. Actually, the correction calculation method may be different depending on the characteristics of the motor used, the detection position of the current detection means 19, and the detection position of the voltage detection means 28.

The equations (1), (2), (5), and (6) shown in the above embodiment are merely examples, and needless to say, the present invention is not limited to these.

[0068]

As described above, according to the first aspect of the invention, based on the voltage detected by the voltage detecting means,
The current calculation means converts the current detected by the current detection means into a current that will flow at a predetermined voltage (for example, AC 100 V or a voltage corresponding thereto). Then, based on the converted detection current and the rotation speed detected by the rotation speed detection means, the flow path resistance determination means determines the flow path resistance of the blower flow path, and the fan motor is rotationally controlled according to the flow path resistance. Therefore, even if the voltage fluctuates, it is possible to properly determine the flow path resistance of the air flow path in which the fan motor blows air, and to appropriately control the rotation of the fan motor according to the state of the flow path resistance. effective.

According to a second aspect of the present invention, a predetermined voltage (for example, AC100) is obtained based on the voltage detected by the voltage detecting means.
The current calculation means converts the current detected by the current detection means into a current that will flow when V (or a voltage corresponding thereto). Then, the flow path resistance determination means determines the flow path resistance of the blower flow path based on the converted detection current and the rotation speed detected by the rotation speed detection means. Further, the optimum air flow rate determination means determines the optimum air flow rate based on the combustion amount of the combustor, and controls the rotation of the fan motor based on the optimum air flow rate and the determined flow path resistance. However, there is an effect that it is possible to appropriately determine the flow path resistance of the air flow path through which the fan motor blows air, and appropriately control the air flow of the combustor according to the state of the flow path resistance.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a hot water supply device including a motor control device of the present invention.

FIG. 2 is a circuit block diagram of a motor drive unit provided with the motor control device of the present invention.

FIG. 3 is a circuit diagram of power control means provided with the motor control device of the present invention.

FIG. 4 is a waveform diagram of a triangular wave obtained by the triangular wave oscillation circuit provided with the motor control device of the present invention.

FIG. 5 is a waveform diagram of a drive voltage supplied to a fan motor provided with the motor control device of the present invention.

FIG. 6 is a flowchart illustrating the operation of the motor control device that controls the fan motor according to the present invention.

FIG. 7 is an explanatory diagram of a relationship between a current flowing through a fan motor controlled by a motor control device of the present invention, a rotation speed, and an air flow rate.

FIG. 8 is an explanatory diagram of a relationship between the detected current by the current detection means provided in the motor control device of the present invention and the rotation speed of the fan motor.

[Explanation of symbols]

1 casing 2 burners 3 heat exchanger 4 fan case 5 fan motor 6 Sirocco fan 7 exhaust port 8 Fuel supply pipe 10 Water pipe 11 valves 12 valves 13 Hot water supply control unit 15 Commercial power supply 16 Rectification smoothing means 17 Power control means 18 Rotation speed detection means 19 Current detection means 20 Duty ratio control means 21 Current calculation means 22 Optimal air flow rate determination means 23 Flow path resistance determination means 24 Optimal rotation speed discrimination means 25 Abnormality discrimination means 26 Abnormality processing means 27 Micro Computer 28 Voltage detection means

Continuation of the front page (56) Reference JP-A-7-190343 (JP, A) JP-A-2-52923 (JP, A) JP-A-6-313541 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) F23N 3/08 F23N 1/10 101

Claims (2)

(57) [Claims] 1. A fan motor control device for controlling the rotation of a fan motor for blowing air, comprising: voltage detection means for detecting information on a drive voltage on the fan motor side; and current for detecting information on a drive current on the fan motor side. A detection means; a current calculation means for correcting and converting the current information detected by the current detection means based on the voltage information detected by the voltage detection means; a rotation speed detection means for detecting the rotation speed of the fan motor; A flow path resistance determination unit that determines the flow path resistance of the air flow path that is blown by the fan motor based on the current information by the current calculation unit and the rotation speed detected by the rotation speed detection unit; and the flow path resistance determination unit. A fan motor control device, wherein the fan motor is rotationally controlled based on the flow path resistance determined by. 2. A fan motor control device for controlling the rotation of a fan motor for blowing air arranged in a blower flow path, comprising: rectifying and smoothing means for rectifying and smoothing AC power to output DC power; Power control means for supplying the DC power of the fan motor as drive power, rotation speed detection means for detecting the rotation speed of the fan motor, voltage detection means for detecting information about the drive voltage on the fan motor side, When a predetermined voltage is applied to the motor side of the current information detected by the current detecting means based on the voltage information detected by the voltage detecting means and the current detecting means for detecting the information about the drive current of the fan motor side. Current calculation means for converting into current information that will flow to
A flow path resistance determination unit that determines the flow path resistance of the blower flow path based on the current calculated by the current calculation unit and the rotation speed detected by the rotation speed detection unit, and the combustion amount of the combustor. Based on the optimum air flow rate determination means for determining the optimum air flow rate based on the optimum air flow rate determined by the optimum air flow rate determination means and the flow path resistance determined by the flow path resistance determination means. A fan motor control device characterized by determining an optimum rotation speed and controlling rotation so that the rotation speed of the fan motor becomes the optimum rotation speed.