JP3339245B2 - 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 so-called PWM type motor control device for rotating a motor by switching DC power obtained by rectifying and smoothing AC power and supplying the switching power to the motor as driving power.

[0002]

2. Description of the Related Art As a conventional motor control device, for example, as described in JP-A-5-164323,
In some cases, when the fan motor current reaches a predetermined value, an alarm lamp blinks or combustion is prohibited.

As a conventional motor control device, for example, as described in JP-A-4-36508,
There has been a configuration in which a wind speed sensor or the like is installed in a blowing passage and the number of revolutions of the fan motor is controlled in accordance with a detection signal from the wind speed sensor or the like.

A conventional motor controller for controlling such a fan motor often uses a variable voltage switching power supply.

[0005]

In a conventional motor control device which is configured to blink an alarm lamp or inhibit combustion when the fan motor current reaches a predetermined value, a wind pressure switch is provided. Although the intake / exhaust failure can be detected without the provision, the appropriate amount of air cannot be maintained in accordance with the flow path resistance of the air flow path, and there has been a problem that optimum combustion cannot be secured. That is, the flow path resistance of the air flow path changes due to various factors such as aging, headwind, flow path length, pressure difference between intake and exhaust, bending of the flow path, clogging of the intake filter, and rotation of the fan motor. Even if the number is controlled to be constant, the air flow rate changes due to the change in the flow path resistance of the air flow path, so if the appropriate motor rotation speed cannot be maintained in accordance with the flow path resistance of the air flow path, the air-fuel ratio Worsens, resulting in poor combustion such as extinction, incomplete combustion, and poor fire.

Further, in a conventional motor control device in which a wind speed sensor or the like is installed in a blowing passage and the number of revolutions of a fan motor is controlled in accordance with a detection signal from the wind speed sensor or the like, Although the air volume can be maintained,
Since a wind speed sensor or the like is installed in the air flow passage, there is a problem that the wind speed sensor or the like causes an increase in flow resistance of the air flow passage and the wind speed sensor or the like increases manufacturing cost.

Further, when a variable voltage switching power supply is used, the variable voltage switching power supply is expensive, large and heavy, and hinders reduction in the cost and weight of the entire apparatus.

In order to solve this problem, a so-called PWM type motor drive IC is used, in which the DC power obtained by rectifying and smoothing the AC power is switched and supplied as drive power to the motor to rotate the motor. It is possible.

However, in this case, since DC power obtained by rectifying and smoothing AC power is supplied to the motor drive IC, the voltage of a commercial power supply generally used as AC power greatly fluctuates, and therefore flows into the motor drive IC. Even if the current is detected, the current flowing through the motor cannot be accurately known. As a result, when the motor is used as a fan motor, it is necessary to accurately calculate the flow path resistance of the air flow path in which the fan is installed. Can not.

That is, since the rotational speed of the motor, the current flowing through the motor, and the flow resistance of the blower flow path have a fixed relationship to each other, if the rotational speed of the motor and the current flowing through the motor are detected, The flow path resistance can be calculated.
In the method, even if the rotation speed of the motor and the flow path resistance do not change, the current flowing into the motor driving IC changes due to the fluctuation of the AC voltage, and even if the current flowing into the motor driving IC is detected, The flow path resistance cannot be calculated.

[0011] The present invention has been proposed in view of the above points, and can reduce the cost and weight of a power supply,
Further, it is an object of the present invention to provide a motor control device capable of accurately grasping a current flowing through a motor and thus accurately determining a flow path resistance. Further, the present invention provides a motor control device that can always maintain an appropriate motor rotation speed according to the flow path resistance of the air flow path without installing an air volume detection unit such as a wind speed sensor in the air flow path. That is the purpose.

[0012]

Means for Solving the Problems To solve the above problems, the present invention takes the following technical means.

That is, according to the invention described in claim 1 of the present application, the blower fan arranged in the blower passage of the combustor is turned on.
Supply power to the fan motor to be
Rectify and flatten AC power
Rectifying and smoothing means for smoothing and outputting DC power, and PWM variable
Control circuit having a speed circuit and generated by the PWM variable speed circuit
The DC power from the rectifying and smoothing means is switched based on the pulse.
Switched and supplied as drive power to the fan motor
Power control means for detecting the number of revolutions of the fan motor
And the output current of the rectifying and smoothing means.
Current detecting means for detecting, a rotation speed command signal and the rotation speed
Based on the rotation speed detected by the detection means,
The control is performed so that the rotation speed of the fan motor becomes the command rotation speed.
Duty ratio control to control pulse duty ratio
Means for calculating the current flowing through the fan motor
Calculating means, and the current calculated by the current calculating means
Based on the rotation speed detected by the rotation speed detection means.
Flow path resistance determining means for determining the flow path resistance of the blower flow path
Wherein the current calculation means is provided by the current detection means.
Output current and the duty ratio control means.
Based on more controlled duty ratio information
Output current detected by the current detection means
By converting the output current to
It is characterized by calculating the current flowing through the data .

The invention described in claim 2 of the present application is
Rotate the fan for ventilation located in the ventilation passage of the combustor.
Supply power to the fan motor to rotate the fan
In the motor control device, the AC power is rectified and smoothed.
Rectifying / smoothing means for outputting DC power by means of
Control pulse generated by the PWM variable speed circuit.
The DC power from the rectifying and smoothing means is switched based on the
And supply it as drive power to the fan motor
Power control means for detecting the number of revolutions of the fan motor
Rotational speed detecting means and output current of the rectifying and smoothing means are detected.
Current detection means for detecting the rotation speed command signal and the rotation speed detection
The fan based on the rotational speed detected by the means.
The control pulse is controlled so that the motor speed becomes the command speed.
Ratio control means for controlling the duty ratio of the motor
And a current calculation for calculating a current flowing through the fan motor
Means and an optimum air flow rate based on the combustion rate of the combustor.
Separate optimal air flow rate determining means and the current calculating means
Calculated current and detected by the rotation speed detecting means
Determining the flow path resistance of the air flow path based on the rotation speed
The determination is made by the flow path resistance determining means and the optimal air flow rate determining means.
Discriminated by the separated optimal air flow and the flow path resistance discriminating means
The optimum rotation of the fan motor based on the
The number of revolutions is determined, and the number of revolutions of the fan motor
So that the duty ratio control means
An optimum rotational speed determining means for supplying a command signal,
The current calculation means outputs the current detected by the current detection means.
Controlled by the force current and the duty ratio control means.
Detecting the current based on information on a duty ratio.
Output current in the PAM system
The current flowing through the fan motor
It is characterized by calculating the flow .

Further, the invention described in claim 3 of the present application is
Duty ratio control means controls the duty ratio of the control pulse by adjusting the control voltage supplied to the power control unit, the current calculation means, a control voltage Vs, the full
The minimum control voltage § down motor rotates Vl, the constant k, when the Io the detected output current by the current detecting means, constituting a current I flowing through the fan motor computed based on the equation 1 It is characterized by having.

[0016]

According to the first aspect of the present invention, the rectifying and smoothing means rectifies and smoothes AC power and outputs DC power . This DC power is PWM controlled by a power control means.
Switching based on control pulse generated by speed circuit
Then, it is supplied as drive power to the fan motor. this
When the fan motor rotates due to the driving power, the rotation speed
Is detected by the rotation speed detecting means. Rectified flat with current detection means
The output current from the sliding means is detected, and this output current and
Of the control pulse controlled by the duty ratio control means
The output current based on the information about the
Current calculation by converting to the output current in the method
The current flowing through the fan motor is calculated by the means. further
The number of rotations and power of the fan motor detected by the rotation speed
The fan motor drive current calculated by the flow calculation means.
Flow resistance of the ventilation channel of a combustor with a fan
Is determined. The duty ratio control means outputs a rotational speed command.
The rotation of the fan motor detected by the signal and the rotation speed detection means
And the number of rotations of the fan motor
Control duty ratio of the control pulse
You. This makes it possible to accurately determine the flow path resistance of the air flow path.
You.

According to the second aspect of the present invention, the rectifying and smoothing means rectifies and smoothes the AC power and outputs the DC power . This DC power is supplied to the power control means by PWM control.
Switch based on control pulse generated by variable speed circuit
And is supplied as drive power to the fan motor.
When the fan motor rotates with this drive power,
The number of revolutions is detected by the number of revolutions detecting means. Set by current detection means
The output current from the flow smoothing means is detected, and this output current and
The duty of the control pulse controlled by the duty ratio control means
The output current to P based on the
By converting to the output current in the AM system, the current
The current flowing to the fan motor is calculated by the calculating means. Sa
The rotation of the fine motor detected by the rotation speed detection means
Drive current of fan motor calculated by number and current calculation means
And the flow in the air flow path of the combustor with the fan
The flow path resistance is determined, and the flow path resistance and the optimal air flow rate determination means are determined.
Of the fan motor based on the optimum airflow determined in
The appropriate rotation speed is determined. De Yuti ratio control means, the most
The fan speed detected by the appropriate airflow and rotation speed detection means
The rotation speed of the fan motor is optimal based on the rotation speed
Control the duty ratio of the control pulse so that it becomes the number of revolutions
I do. This allows the fan motor to operate at the maximum
Rotate at an appropriate speed.

According to the third aspect of the present invention, the duty ratio control means controls the duty ratio of the control pulse by adjusting the control voltage supplied to the power control means. the Vs, the minimum control voltage Vl fan motor <br/> over motor rotates, the constant k, when the Io the detected output current by the current detecting means, a current I flowing through the fan motor I = kIo / (Vs
-Vl) .

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.
This will be specifically described with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic configuration diagram of a water heater provided with a motor control device according to Embodiment 1 of the present invention, and a burner 2 and a heat source are provided inside a casing 1 of the water heater. An exchange 3 is arranged. Fan case 4 continuous below casing 1
Is provided with a sirocco fan 6 driven by a fan motor 5.
An exhaust port 7 is formed. The burner 2 is connected to a fuel supply pipe 8 for supplying a fuel such as gas or oil, and the heat exchanger 3 is connected to a water supply pipe 10 for supplying water. Fuel supply pipe 8 and water supply pipe 1
0 is provided with valves 11 and 12, 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, for example, 100 VAC and outputting DC power, and a DC power from the rectifying / smoothing means 16 based on a control pulse. Power control means 17 for switching the power supply to supply the drive power to the fan motor 5, 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 and smoothing means 16. And controlling the duty ratio of the control pulse based on 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 so that the rotation speed of the fan motor 5 becomes the command rotation speed. Duty ratio control means 20 and current detection means 19
Current and duty ratio control means 2 detected by
Current calculating means 21 for calculating the current flowing through the fan motor 5 based on the information on the duty ratio controlled by 0, and optimal blowing amount determining means 22 for determining the optimum blowing amount based on the combustion amount of the burner 2. , Current calculation means 2
Flow path resistance determining means 23 for determining the flow path resistance of the air flow path formed by the fan case 4 and the casing 1 based on the current calculated by 1 and the rotation speed detected by the rotation speed detection means 18; The optimum rotation speed of the fan motor 5 is determined based on the optimum air flow amount determined by the optimum air flow amount determination unit 22 and the flow path resistance determined by the flow path resistance determination unit 23, and the rotation speed of the fan motor 5 is optimized. An abnormality detecting means for supplying an instruction signal for the number of revolutions to the duty ratio control means so that the number of revolutions becomes equal to the number of revolutions; A determination unit 25; 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. There. In addition, the duty ratio control means 20, the current calculation means 21, and the
2, flow path resistance determining means 23, and optimum rotational speed determining means 2
4, an abnormality determination unit 25, and an abnormality processing unit 26 are realized by a microcomputer 27. In addition,
The microcomputer 27 controls the entire combustion device.

FIG. 2 is a circuit block diagram of a driving unit of the fan motor 5, and the driving unit mainly includes a motor driving IC.
31. This motor drive IC 31
Has terminals 31a to 31e, and is equipped with a power control unit 17 and a rotation speed detection unit 18. The power control unit 17 includes a motor driver 32 that supplies driving power to each coil of the fan motor 5, and a PWM variable speed circuit 33 that switches driving power supplied to the fan motor 5 by the motor driver 32.
The rotation number detecting means 18 calculates the rotation number of the fan motor 5 based on a detection signal from a Hall IC 34 including a plurality of Hall elements built in the fan motor 5, and the rotation logic 35 calculates the rotation number. A rotation speed pulse generating circuit 3 for generating a rotation speed pulse according to the rotation speed
6 is provided. The rectifying and smoothing means 16 is connected to the terminal 31a.
And the driving power is supplied to the motor driver 32 of the power control means 17. Terminal 31
DC power from the auxiliary power supply 37 is input to b, and this DC power is supplied to each part of the motor drive IC 31 as power. The terminal 31c is connected to the duty ratio control means 20.
, And the control voltage is supplied to the PWM variable speed circuit 33 of the power control unit 17. Terminal 31d
From the rotation speed pulse generating circuit 3 of the rotation speed detecting means 18.
6 is output, and the number of rotation pulses is supplied to the duty ratio control means 20. Terminal 31e
Is a ground terminal.

The rectifying / smoothing means 16 is realized by, for example, a full-wave rectifier composed of a diode bridge and a smoothing circuit composed of a capacitor. Output power. The power control means 17 performs rectification and smoothing means 1 based on a control pulse whose duty ratio is controlled in accordance with a control voltage from the duty ratio control means 20.
6 by switching the DC power from the fan motor 5
As driving power. That is, the fan motor 5
Is controlled by the power control means 17 in PWM. The rotation number detecting means 18 is a Hall IC 3 including a plurality of Hall elements built in the fan motor 5.
4 based on the detection signal from the rotation detection sensor
The rotation number of the fan motor 5 is detected, and a rotation number pulse corresponding thereto is supplied to the duty ratio control means 20, and a rotation signal corresponding to the rotation of the rotor of the fan motor 5 is supplied to the power control means 17. The current detecting unit 19 includes, for example, a current transformer, and detects the output current of the rectifying / smoothing unit 16. Duty ratio control means 2
0 means that the control voltage is adjusted so that the rotation speed of the fan motor 5 becomes the command rotation speed, and the control voltage is
7 The fan motor 5 is a three-phase brushless motor, more specifically, a permanent magnet type synchronous motor. In the present embodiment, the fan motor 5 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. The power control means 17 includes a triangular wave oscillation circuit 41, a comparator 42, a three-phase distribution circuit 43, and transistors TR1 to TR6. ing. Components not directly related to the present invention, such as transistors TR1 to TR6 , protection diodes, and circuits for detecting and protecting overcurrents flowing through coils 5a to 5c of fan motor 5, are illustrated and illustrated. Description is omitted.

The triangular wave oscillation circuit 41 has a frequency of, for example, 20 kHz.
Outputs a triangular wave with a period of. The comparator 42 is composed of an operational amplifier. The voltage of the triangular wave from the triangular wave oscillating circuit 41 and the control voltage Vs
And outputs a control pulse having a period of 20 KHz, which turns on when the control voltage Vs is equal to or higher than the voltage of the triangular wave and turns off when the control voltage Vs is lower than the voltage of the triangular wave. 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 responds to the rotation signal from the rotation speed detecting means 18 by using the upper transistors TR1-T
R3 and one of the lower transistors TR4 to TR4.
One of R6 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 direction of the current and the coils 5a to 5c through which the current flows according to the rotation position of the rotor of the fan motor 5. Further, the three-phase distribution circuit 43 sets the transistors to be turned on among the lower transistors TR4 to TR6,
It is turned on / off according to a control pulse from the comparator 42. That is, the three-phase distribution circuit 43 converts the drive power supplied to the fan motor 5 to the duty ratio control unit 20.
PWM control according to the control voltage Vs from

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 and smoothing means 16 and supplied to the fan motor 5 via the power control means 17 as drive power. At this time, the PWM control is performed by the power control unit 17, and the drive voltage to the fan motor 5 is controlled such 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 oscillation circuit 41 is Vh, the minimum voltage is Vl, 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 voltage of the triangular wave, and turns off when the control voltage Vs is smaller than the voltage of the triangular wave. The pulse train has the same cycle as Then, 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 lower transistors TR4 to TR6, so that the driving power of the fan motor 5 is switched by the control pulse. In addition, the driving power according to the duty ratio of the control pulse is supplied to the fan motor 5.

FIG. 6 is a circuit diagram of the current detecting means 19. The current detecting means 19 includes a current transformer CT1.
, Operational amplifiers OP1, OP2, and variable resistors VR1,
VR2, resistors R30 to R35, capacitor C2,
C3. A resistor R30 is connected to the output terminal of the current transformer CT1.
Is grounded at one end. The other end of the resistor R30 is connected to a non-inverting input terminal of the operational amplifier OP1. The inverting input terminal of the operational amplifier OP1 is grounded via a resistor R31, and a parallel circuit of a resistor R32 and a capacitor C2 is connected between the output terminal and the inverting input terminal of the operational amplifier OP1. The output terminal of the operational amplifier OP1 is connected to a resistor R34.
Is connected to the inverting input terminal of the operational amplifier OP2, and a series circuit of a resistor R33 and a variable resistor VR1 is interposed between the DC voltage VCC and the ground. The slider of the variable resistor VR1 is connected to the non-inverting input terminal of the operational amplifier OP2, and the output terminal of the operational amplifier OP2 is connected to one end of the variable resistor VR2. Variable resistor VR2
Is connected to an inverting input terminal of an operational amplifier OP2 via a parallel circuit of a resistor R35 and a capacitor C3.

Current transformer CT1 and operational amplifier OP
1, the resistors R30 to R32, and the capacitor C2 constitute a current / voltage conversion circuit that converts the magnitude of the current flowing through the fan motor 5 into a voltage. The resistor R33 and the variable resistor VR1 constitute a reference voltage circuit that generates a reference voltage. The operational amplifier OP2 and the resistor R34 are
The amplifier circuit amplifies the difference between the output of the current / voltage conversion circuit and the output of the reference voltage circuit. Variable resistor VR2
The resistor R35 and the capacitor C3 constitute a feedback circuit that feeds back the output of the amplifier circuit to the input side. The variable resistor VR1 constitutes a first adjusting unit for adjusting the reference voltage generated by the reference voltage circuit. The variable resistor VR2 constitutes a second adjusting unit for adjusting the feedback ratio by the feedback circuit.

In the current detecting means 19, the voltage input to the non-inverting input terminal of the operational amplifier OP2 changes by moving the slider of the variable resistor VR1. That is, when the slider of the variable resistor VR1 is moved, it is amplified by the operational amplifier OP2.
, The relationship between the current flowing through the current transformer CT1 and the detection voltage E appearing at the output terminal of the operational amplifier OP2 changes. Therefore, FIG.
As shown in the figure, the rotation speed N of the fan motor 5 and the detection voltage E
By moving the slider of the variable resistor VR1, the level shifts, for example, from a solid line state to a broken line state. As a result, if there is a variation in the level of the characteristic between the current flowing through the individual fan motors 5 and the number of rotations during manufacturing, the level can be adjusted by the variable resistor VR1 to adjust the detection characteristic in advance.

When the slider of the variable resistor VR2 is moved, the resistance value of the variable resistor VR2 changes, so that the feedback ratio changes and the amplification factor of the operational amplifier OP2 changes. The relationship between the current flowing through CT1 and the detection voltage E appearing at the output terminal of the operational amplifier OP2 changes. Therefore, as shown in FIG.
The relationship between the rotation speed N and the detection voltage E of the variable resistor VR2
By moving the slider, the inclination changes, for example, from a solid line state to a broken line state. As a result, if the characteristics of the current flowing through the individual fan motors 5 and the rotation speed vary in the manufacturing process, the characteristics can be adjusted by the variable resistor VR2 to adjust the detection characteristics in advance.

Next, the operation of the water heater will be described with reference to FIG.
This will be described with reference to the flowchart shown in FIG. When an operation command is input from a remote controller (not shown) to the controller, the hot water supply control unit 13 controls the valves 11 and 12 and an igniter (not shown) to start the ignition operation, and to A signal corresponding to the combustion amount of the burner 2, that is, the valve opening amount of the valve 11 is output. Thereby, the optimum air blowing amount determining means 22 calculates the optimum air blowing amount 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 result of the discrimination by the passage resistance discriminating means 23 is the optimum rotation.
Since it is not supplied to the number discriminating means 24 , the optimum revolution number discriminating means 24 outputs to the duty ratio control means 20 a preset revolution number command signal corresponding to a preset initial revolution number of, for example, about 3000 revolutions per minute (step S2). ). As a result, the duty ratio control means 20 supplies a control voltage Vs to the power control means 17 such that the fan motor 5 rotates at the initial rotation speed. As a result, the power control means 17
The driving power is controlled by the method, and the fan motor 5 is driven to rotate at the initial rotation speed.

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

Next, the current detecting means 19 detects the output current of the rectifying / smoothing means 16 (step S4). That is, a voltage corresponding to the output current of the rectifying / smoothing means 16 is induced in the current transformer CT1, applied to the resistor R30, and input to the non-inverting input terminal of the operational amplifier OP1. The operational amplifier OP1 amplifies the voltage input to the non-inverting input terminal at an amplification factor determined by the resistors 31 and 32, and supplies the amplified voltage to the inverting input terminal of the operational amplifier OP2 via the resistor R34. As a result, the operational amplifier OP2 becomes
The difference voltage between the voltage input to the non-inverting input terminal of the amplifier and the output voltage of the operational amplifier OP1 is determined by the variable resistor VR2 and resistor R3.
4 and R35, and amplifies at an amplification factor determined by R35, and outputs as a detection voltage E. This detection voltage E is calculated by the current calculation means 21.
Supplied to

Next, the rotation speed detecting 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 calculating means 21 calculates the output current of the rectifying / smoothing means 16 detected by the current detecting means 19,
Using the control voltage Vs from the duty ratio control means 20, the current flowing through the fan motor 5 is calculated by the above equation (Step S6).

That is, if there is no fluctuation in the voltage of the commercial power supply 15 and the output voltage of the rectifying / smoothing means 16 is always constant,
There is little need to correct the output current of the rectifying / smoothing means 16 detected by the current detecting means 19, but in reality, for example, in the case of a commercial power supply 15 of 100 volts AC, it fluctuates to 75 to 120 volts. In order to correct the difference between the change in the output current of the rectifying / smoothing means 16 and the current flowing through the fan motor 5 due to the fluctuation, the current calculating means 21 calculates the fan motor 5 from the output current of the rectifying / smoothing means 16.
It is necessary to calculate the current flowing through the rectifier and correct the actually detected output current of the rectifying / smoothing means 16. Here, in order to make the description easier to understand, first, a flow path resistance determining operation in the case where it is not necessary to correct the output current of the rectifying / smoothing means 16 will be described.

The flow path resistance judging means 23 comprises the current detecting means 1
9 (that is, the current before being corrected by the current calculation unit 21 in this description) and the rotation speed pulse from the rotation speed detection unit 18, the fan case 4
Then, the flow path resistance Φ of the air flow path in the casing 1 is determined (step S7). That is, the relationship between the rotation speed N of the fan motor 5 and the current I flowing through the fan motor 5 is shown in FIG.
As shown in FIG. 0, the rotation speed N and the current I are changed in accordance with the flow path resistance Φ. I
From this, the flow path resistance Φ can be determined. For example, if the rotational speed N is N
When the current is 1, the current I becomes I0, or the rotation speed N becomes N
2, when the current I becomes I1, it can be determined that the flow path resistance Φ is Φ1, and when the rotational speed N is N0, the current I becomes I0.
, It can be determined that the flow path resistance Φ is Φ0. Note that Φ0 is smaller than Φ1. In addition, this flow path resistance Φ
Assuming that the number of revolutions of the fan motor 5 is N and the current flowing through the fan motor 5 is I, for example, it can be obtained experimentally by the following equation 2. Where g (N) and f (N) are the rotation speed N
Is a function of Alternatively, as another experimental formula, it is obtained by the following mathematical formula 3.

[0040]

(Equation 2)

[0041]

[Equation 3]

Next, the operation in which the current calculating means 21 corrects the current detected by the current detecting 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-described method. However, since the voltage of the commercial power supply 15 fluctuates in practice, it can be determined only by the above-described method. However, correction by the current calculation means 21 is required.

Generally, in the PAM system, the fan motor 5
When power is supplied to the fan motor 5, the fan motor 5 can be driven by a stable DC power supply.
In the WM method, since the AC power is driven by a DC power supply that is only rectified and smoothed, there is an advantage that the power supply unit can be simplified. However, on the other hand, when the voltage of the commercial power supply 15 fluctuates, as shown in FIG. 11, the fluctuation fluctuates the output voltage of the rectifying / smoothing means 16, and this fluctuation is absorbed by a change in the duty ratio of PWM. Control, the output current I of the rectifying / smoothing means 16 for the same rotational speed is controlled.
o will also fluctuate. Therefore, in the case of the PWM method, the current value of the fan motor 5 at the same rotation speed is equal to the fluctuation of the flow path resistance of the intake and exhaust passages and the fluctuation of the voltage of the commercial power supply 15.
It will fluctuate by two factors.

Therefore, the current calculation means 21 determines in step S
In step 6, the current I flowing through the fan motor 5 is calculated using the output current Io detected by the current detecting means 19. This has the same meaning as correcting the current that would be detected when the voltage of the commercial power supply 15 is 100 volts. Specifically, the calculation is performed by using the above-described Expression 1.

Equation 1 can be obtained as follows. That is, to simplify and explain, the PWM method shown in FIG. 12 can be expressed as shown in FIG. 13 in the PAM method. Rectifying smoothing means 1 in PWM system
6, the output voltage is Vo, the output current is Io, the output voltage of the variable voltage power supply 51 in the PAM system is V, and the output current is I.
Further, when the electric / mechanical work conversion efficiencies in the respective methods are considered to be equal and 100%, the following Expression 4 is satisfied.

[0046]

(Equation 4)

Here, the voltage applied to the fan motor 5 in the PWM system is in a pulse form as shown in FIG. 5, and the hatched portion corresponds to the applied voltage V in the PAM system. The control voltages Vs, Vh,
When represented by Vl, the following equation 5 is obtained.

[0048]

(Equation 5)

Since this corresponds to the applied voltage V in the PAM system, the following equation 6 is established.

[0050]

(Equation 6)

By substituting Equation 6 above into Equation 4, the following Equation 7 is established.

[0052]

(Equation 7)

When the above equation (7) is modified, the following equation (8) is obtained.

[0054]

(Equation 8)

Here, the voltage width Vh- of the triangular wave shown in FIG.
Assuming that Vl is a constant k, Expression 8 becomes the same as Expression 1. If the constant k is, for example, 3.5 volts,
The following equation 9 holds.

[0056]

(Equation 9)

Equations (1), (8) and (9) show that the output current Io detected by the current detecting means 19 in the PWM system is represented by P
This is converted into a detection current I in the AM system.

As described above, in step S6, the current I flowing through the fan motor 5 is calculated by the current calculating means 21, so that the output current Io detected by the current detecting means 19 is corrected. In step S7, the correction is performed. 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.

Next, the abnormality determination means 25 determines whether or not the flow path resistance Φ determined by the flow path resistance determination means 23 is between a predetermined lower limit value ΦL and a predetermined upper limit value ΦH. (Step S8). That is, a region where the flow path resistance Φ deviates from between the lower limit value ΦL and the upper limit value ΦH is shown by hatching in FIG. 14, but when the flow path resistance Φ becomes such a value, the fan motor 5 Even if the number of rotations is controlled, an appropriate amount of air cannot be secured, so that it is necessary to determine that the fan motor 5 is in an abnormal state. If the flow path resistance Φ is between the lower limit ΦL and the upper limit ΦH, By controlling the number of revolutions, an appropriate amount of air can be secured, so that it can be determined that the air condition is normal. The first quadrant in FIG. 14 represents the relationship between the current I flowing through the fan motor 5, the number of revolutions N, and the flow path resistance Φ, and the fourth quadrant represents the number of revolutions N of the fan motor 5 and the air volume Q.
And the flow path resistance Φ.

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

Next, the optimum rotational speed discriminating means 24 determines the optimum rotational speed based on the flow path resistance Φ determined by the flow path resistance determining means 23 and the optimum air flow rate determined by the optimal air flow rate determining means 22. Is calculated (step S10), and a rotation speed command signal is output to the duty ratio control means 20. That is, as shown in FIG.
Since the relationship between and the flow rate Q changes with the flow path resistance Φ, the optimum rotation speed is determined according to the flow path resistance Φ so as to obtain the optimum flow rate. This optimum rotation speed Ns is
Assuming that the optimal air flow rate is Q0 and the reference rotation speed determined based on the reference flow path resistance Φ0 and the combustion amount is Ng,
For example, it is obtained by the empirical formula of the following Expression 10. Alternatively, it can also be obtained by the following equation 11 as another experimental equation.

[0062]

(Equation 10)

[0063]

(Equation 11)

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

As a result, the power control means 17 performs the control based on the control voltage Vs from the duty ratio control means 20.
Switching the DC power supplied to the fan motor 5,
The fan motor 5 is driven so as to have an optimum rotation speed.

Next, the optimum air blowing amount determining means 22 determines whether or not the combustion amount has been changed based on a signal from the hot water supply control unit 13 (step S12). It is determined whether or not an instruction to end the operation has been input from the remote controller (step S13), and if not, the process returns to step S5. If so, the routine ends.

If it is determined in step S12 that the optimum amount of air has been changed, the flow returns to step S1.

In step S8, the abnormality determining means 25
, The flow path resistance Φ is a predetermined lower limit ΦL and upper limit Φ
If it is determined that the time does not fall between H and H, the abnormality determination means 25 further determines whether the built-in timer has expired (step S14), and if not, the process proceeds to step S10. If the time is up, an error is output to the abnormality processing means 26. That is, since the flow path resistance Φ may constantly change due to the influence of the wind or the like, an abnormal state is determined only when the flow path resistance Φ has an abnormal value for a predetermined time or more.

Next, the abnormality processing unit 26 outputs a stop signal to the hot water supply control unit 13 to stop the combustion of the burner 2 by inputting a signal indicating an abnormality from the abnormality determination unit 25, for example. (Step S1)
5) End the routine.

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 is switched based on the control pulse to drive the fan motor 5 as driving power. A power control unit 17 to be supplied, a rotation speed detection unit 18 for detecting the rotation speed of the fan motor 5, a current detection unit 19 for detecting the output current of the rectification smoothing unit 16, a rotation speed command signal and a rotation speed detection unit 18 And duty ratio control means for controlling the duty ratio of the control pulse so that the rotation speed of the fan motor 5 becomes the required rotation speed, based on the rotation speed detected by the control unit, and the output current detected by the current detection means 19. A current flowing through the fan motor 5 is calculated based on the information on the duty ratio controlled by the duty ratio control means 20. Since there is provided a current calculation unit 21,
The current flowing through the fan motor 5 can be accurately known irrespective of the voltage fluctuation of the commercial power supply 15, so that the flow path resistance can be properly determined.

Further, the flow path resistance determining means 23 for determining the flow resistance of the air flow path based on the current calculated by the current calculating means 21 and the rotation speed detected by the rotation speed detecting means 18 is provided. Thus, the flow path resistance of the air flow path can be properly determined. Therefore, it is possible to maintain an appropriate motor rotation speed according to the flow path resistance of the air flow path.

Further, 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. Is provided with an optimum rotation speed discriminating means 24 for supplying a rotation speed command signal to the duty ratio control means 20 so that the rotation speed of the motor becomes the optimum rotation speed. Can always be maintained. Therefore, even if the flow path resistance changes, the optimum air flow can always be maintained.

Further, an abnormality judging means 25 for judging an abnormal combustion based on the flow path resistance judged by the flow path resistance judging means 23, and a burner 2 when the abnormality judging means 25 judges that the combustion is abnormal. Since the abnormality processing means 26 for stopping the combustion is provided, it is possible to accurately determine the abnormality of the combustion from the flow path resistance at a stage before the flame of the burner 2 disappears, and to improve the safety.

(Embodiment 2) FIG. 15 is a schematic configuration diagram of a water heater provided with a fan motor control device according to Embodiment 2 of the present invention, which is different from the water heater of Embodiment 1 shown in FIG. As a component realized by the microcomputer 27, the air supply for estimating the actual air flow rate based on the flow path resistance determined by the flow path resistance determination means 23 and the rotation speed detected by the rotation speed detection means 18 is described. The difference is that an air volume estimating unit 52 and a target rotational speed determining unit 53 for determining a target rotational speed of the fan motor 5 based on the combustion amount of the burner 2 are added. Therefore, the optimum rotation speed discrimination means 24 discriminates the deviation between the optimum air flow rate determined by the optimum air flow rate discrimination means 22 and the actual air flow rate estimated by the air flow rate estimation means 52, and the target rotation speed discrimination means 53. The optimum rotation speed of the fan motor 5 is determined based on the set target rotation speed. Also, the abnormality determining means 25
Determines abnormal combustion based on the actual blown air amount estimated by the blown air amount estimating means 52. Other configurations are shown in FIG.
This is the same as the hot water supply device of the first embodiment shown in FIG.

Next, the operation of the water heater will be described with reference to FIG.
This will be described with reference to the flowchart shown in FIG. When an operation command is input from a remote controller (not shown) to the controller, the hot water supply control unit 13 controls the valves 11 and 12 and an igniter (not shown) to start the ignition operation, and to A signal corresponding to the combustion amount of the burner 2, that is, the valve opening amount of the valve 11 is output. Thereby, the optimum air blowing amount determining means 22 calculates the optimum air blowing amount according to the combustion amount of the burner 2 based on the signal from the hot water supply control unit 13 (Step S21).

Next, the target rotational speed discriminating means 53 calculates a target rotational speed for obtaining an optimum air flow according to the combustion amount of the burner 2 based on the signal from the hot water supply controller 13 (step S22). ).

At this time, the fan motor 5 is not rotating, and the result of the discrimination by the flow path resistance discriminating means 23 is not supplied to the optimum revolution number discriminating means 24. A rotation speed command signal corresponding to the initial rotation speed of about 3000 rotations per minute is output to the duty ratio control means 20 (step S23). As a result, the duty ratio control means 20 outputs a control voltage Vs to the power control means 17 such that the fan motor 5 rotates at the initial rotation speed. Thus, the power control unit 17 controls the duty ratio of the driving power so that the fan motor 5 rotates at the initial rotation speed.

Next, the abnormality determining means 25 starts a built-in timer (step S24).

Next, the current detecting means 19 detects the output current Io of the rectifying / smoothing means 16 (step S25).

Next, the rotation speed detecting means 18 detects the rotation speed of the fan motor 5 based on the detection signal from the hall element 34 of the fan motor 5 (step S26).

Next, the current calculation means 21 uses the output current Io detected by the current detection means 19 and the control voltage Vs output from the duty ratio control means 20 to flow to the fan motor 5 using the above equation (1). The current I is calculated (step S27).

Next, the flow path resistance determining means 23 compares the current I calculated by the current calculating means 21 with the rotational speed detecting means 18.
Then, the flow path resistance Φ of the air flow path in the fan case 4 and the casing 1 is determined on the basis of the rotation speed pulse from (Step S28).

Next, the blower amount estimating means 52 determines the actual value based on the flow path resistance Φ determined by the flow path resistance determining means 23 and the rotational speed N of the fan motor 5 detected by the rotational speed detecting means 18. Is calculated (step S2).
9). That is, as shown in FIG.
The relationship between the actual rotation speed N and the actual air flow rate Q changes with the change in the flow path resistance Φ of the air flow path. However, if the flow path resistance Φ is determined, it is uniquely determined accordingly. By calculating the relationship between the flow rate and the flow resistance Q and the air flow rate Q and storing it in a memory in advance, the actual air flow rate Q can be calculated from the rotation speed N of the fan motor 5 and the flow resistance Q.

Next, the abnormality determining means 25 determines whether or not the blown air amount Q estimated by the blown air amount estimating means 52 falls between a predetermined lower limit value QL and a predetermined upper limit value QH ( Step S30).

The abnormality discriminating means 25 determines that the blown air amount Q
If it is between L and the upper limit QH, it is determined to be normal,
The built-in timer is cleared (step S31).
As soon as this timer is cleared, it restarts and resumes the timing operation.

Next, the optimum rotation number discriminating means 24 calculates the difference between the actual air volume Q1 estimated by the air volume estimating means 52 and the optimal air volume Q0 determined by the optimal air volume discriminating means 22. The optimum rotational speed N is calculated by using the following equation (12).
1 is calculated (step S32). That is, the sum of the proportional component and the integral component of the difference between the optimum air flow amount Q0 and the estimated actual air flow amount Q1 is added to the target rotation speed N0 as a feedback component. Therefore, the optimal air volume Q0
If the deviation from the actual airflow amount Q1 estimated to be stable in a state of zero, the target rotation speed N0 becomes the optimum rotation speed N1.

[0087]

(Equation 12)

Further, the optimum rotation speed discriminating means 24 outputs a rotation speed command signal corresponding to the calculated optimum rotation speed to the duty ratio control means 20 (step S33).

Thus, the duty ratio control means 20
However, based on the rotation speed command signal from the optimum rotation speed determination unit 24 and the actual rotation speed from the rotation speed detection unit 18, the power control unit 1 controls the fan motor 5 to the optimum rotation speed.
7, the control voltage Vs is output. Thereby, the power control unit 17 varies the duty ratio of the driving power so that the fan motor 5 has the optimum rotation speed.

Next, the optimum air blowing amount determining means 22 determines whether or not the combustion amount has been changed based on a signal from the hot water supply control unit 13 (step S34). It is determined whether or not an instruction to end the operation has been input from the remote controller (step S35), and if not, the process returns to step S25. If so, the routine ends.

In step S34, if the optimum air volume determining means 22 determines that the combustion amount has been changed, the process returns to step S21.

In step S30, the abnormality determining means 2
5 is the lower limit value QL and the upper limit value
H, if it is determined that there is no gap between the
5 determines whether the built-in timer has timed out (step S36), and if not, proceeds to step S32. If the time is up, an error is output to the abnormality processing means 26. That is, since the blown air amount Q may constantly change due to the influence of the wind and the like, the abnormal state is determined only when the blown air amount Q becomes an abnormal value for a predetermined time or more.

Next, the abnormality processing means 26
By receiving a signal indicating that there is an abnormality from No. 5,
Abnormal processing such as outputting a stop signal to the hot water supply control unit 13 to stop combustion of the burner 2 is performed (step S3).
7), end the routine.

As described above, the rotation speed detection means 18 for detecting the rotation speed of the fan motor 5, the current calculation means 21 for calculating the current flowing through the fan motor 5, and the current calculation means 21
Resistance determining means 23 for determining the flow resistance of the air flow path of the casing 1 and the fan case 4 based on the calculated value of the rotation speed and the rotation speed detected by the rotation speed detecting means 18.
And a flow rate estimating means 52 for estimating an actual air flow rate based on the flow path resistance determined by the flow path resistance determining means 23 and the rotational speed detected by the rotational speed detecting means 18. It is possible to accurately estimate the actual air flow rate without installing an air flow rate detecting means such as a wind speed sensor in the air flow path. Therefore, it is possible to appropriately control the fan motor 5 from the estimated air flow rate without causing an increase in the flow path resistance by the air flow rate detecting means such as a wind speed sensor. In addition, since it is not necessary to install an air volume detecting means such as a wind speed sensor in the air flow channel, manufacturing costs can be reduced.

Further, the optimum air volume determining means 22 for determining the optimum air volume based on the combustion amount of the burner 2 and the optimum air volume and the air volume estimating means 52 estimated by the optimum air volume determining means 22 are estimated. An optimum rotation speed determining means for determining an optimum rotation speed of the fan motor based on a deviation from an actual air flow; and controlling the fan motor to be the optimum rotation speed determined by the optimum rotation speed determining device. Duty ratio control means 20 and power control means 17
Thus, the fan motor 5 can be appropriately controlled by estimating the actual air flow rate without installing an air flow rate detecting means such as a wind speed sensor in the air flow path. Therefore, irrespective of a change in flow path resistance or the like, optimum combustion can be always maintained.

Further, a target rotation number discriminating means 53 for discriminating a target rotation number of the fan motor 5 based on the combustion amount of the burner 2, and an optimum air blowing amount and air blowing amount estimating means 52 determined by the optimum air blowing amount determining means 22. The optimum rotation speed discriminating means 24 for discriminating the optimum rotation speed of the fan motor 5 based on the deviation from the actual air flow rate estimated by the above and the target rotation speed discriminated by the target rotation speed discriminating means 53 is provided. The target rotation speed determined by the rotation speed determination means 53 is set to N0, and the optimum air flow rate determined by the optimum air flow rate determination means 22 is set to Q.
0, when the actual air volume estimated by the air volume estimating unit 52 is Q1, and the predetermined constants are Kp and Ki, the optimal rotational speed determining unit 24 calculates the optimal rotational speed N1 according to the above equation (12). With this configuration, the fan motor 5 can be appropriately controlled by estimating the actual air flow rate without installing an air flow rate detection unit such as a wind speed sensor in the air flow path. Therefore, irrespective of a change in flow path resistance or the like, optimum combustion can be always maintained. In addition, since the motor speed is controlled by the PI control using the deviation between the optimum air volume and the estimated actual air volume, the fan motor 5 can be controlled smoothly.

Further, abnormality determining means 25 for determining abnormal combustion based on the actual air flow estimated by the air flow estimating means 52, and the burner 2 when the abnormality determining means 25 determines abnormal combustion. Since the abnormality processing means 26 for stopping the combustion is provided, it is possible to accurately judge the abnormality of the combustion from the amount of air blow before the flame of the burner 2 is extinguished, thereby improving safety.

(Embodiment 3) As shown in FIG.
The relationship between the air flow rate Q, the rotation speed N, and the current Io as shown in FIG. 10 is stored in the form of a table for each voltage Vac of the commercial power supply 15, and the rectifying / smoothing means 16 In addition to detecting the output current Io, the voltage Vac of the commercial power supply 15 is detected, and the ROM
54, the current Io may be corrected.

(Embodiment 4) As shown in FIG. 18, in addition to detecting the output current Io of the rectifying / smoothing means 16 by the current detecting means 19,
And the correction circuit 55 detects the output current Iac
o may be corrected to the current I by the voltage Vac, and the current I may be input to the microcomputer 27.

In the second embodiment, in step S30 of FIG. 16, the abnormality determining means 25 determines that the actual blown air amount Q estimated by the blown air amount estimating means 52 is between the lower limit value QL and the upper limit value QH. Although the abnormality is determined based on whether the value is a value or not, the abnormality determining unit 25 determines the optimum air flow rate determined by the optimum air flow amount determining unit 22 and the actual air flow estimated by the air blowing amount estimating unit 52. The abnormality may be determined based on whether or not the deviation from the above is equal to or more than a predetermined upper limit value. Even in this case, the abnormality of the combustion can be accurately determined at the stage before the flame of the burner 2 disappears, and the safety can be improved.

In the first and second embodiments, a timer is incorporated in the abnormality determining means 25, and when the value of the flow path resistance Φ or the blown air amount Q is outside the predetermined range for a predetermined time or more. However, it is not always necessary to provide a timer, and if the value of the flow path resistance Φ or the blown air amount Q is out of the predetermined range, the abnormality may be immediately determined.

Further, in the first and second embodiments, in step S2 of FIG. 9 or step S23 of FIG.
Is output in accordance with the predetermined initial rotation speed. However, the optimum rotation speed determination means 24 outputs the rotation speed command signal corresponding to the optimum air flow rate determined by the optimum air flow rate determination means 22. May be output to the duty ratio control means 20.

In each of the above embodiments, the fan motor 5 is controlled by the motor control device according to the present invention. However, the motor control device according to the present invention is not limited to the fan motor 5 but may be controlled by a PWM method. It can be used for any driven motor.

In the first and second embodiments, the detection characteristics can be adjusted by the variable resistors VR1 and VR2 of the current detecting means 19. However, the present invention can be realized even if this adjusting function is omitted. is there. The current detecting means 19 is realized by using the current transformer CT1. For example, a resistor may be arranged in the current line provided with the current transformer CT1 in place of the current transformer CT1 to detect the voltage. May be used to detect the amount of current. In any case, the current detecting means 19
Not limited to these, as long as the current amount can be detected,
The current detecting means 19 can be realized.

[0105]

As described above, according to the first aspect of the present invention, the fan for blowing air disposed in the air flow path of the combustor.
Supply current to the fan motor to rotate the fan
In the motor control device, the AC power is rectified and
Rectifying and smoothing means for smoothing and outputting DC power;
It has a variable speed circuit and is generated by this PWM variable speed circuit.
The DC power from the rectifying / smoothing means is switched based on the control pulse.
Switched and supplied as drive power to the fan motor
Power control means for detecting the rotation speed of the fan motor
Detecting the output current of the rotation speed detecting means and the rectifying and smoothing means
The current detection means, the rotation number command signal and the rotation number detection means
Rotation of the fan motor based on the detected rotation speed.
The duty of the control pulse so that the number becomes the command speed
Duty ratio control means for controlling the ratio, and a fan motor
Current calculating means for calculating the current flowing through
Detected by the current and the rotation speed detecting means.
Flow to determine the flow path resistance of the air flow path based on the
Road resistance determining means, and the current calculating means includes a current detecting means.
Output current detected by the stage and duty ratio control means
Information on the duty ratio controlled by
Output current detected by the current detection means
The fan current by converting the output current
Since the flowing current is calculated, the flow path of the air flow path
Resistance can be accurately determined.

According to the second aspect of the present invention, the combustion chamber
A fan that rotates the fan for air blowing arranged in the air flow path
Motor that supplies power to the motor and rotates the fan
In the control device, the AC power is rectified and smoothed to
Rectifying smoothing means for outputting force and PWM variable speed circuit
Then, based on the control pulse generated by the PWM variable speed circuit,
Switching the DC power from the rectifying and smoothing means
Power control means for supplying drive power to the fan motor
Rotation speed detecting means for detecting the rotation speed of the fan motor
And current detecting means for detecting the output current of the rectifying and smoothing means
And current calculation means for calculating the current flowing through the fan motor
And determining the optimal air flow rate based on the combustion volume of the combustor.
The suitable air flow amount determining means and the electric power calculated by the current calculating means are used.
Based on the flow and the rotation speed detected by the rotation speed detection means
Flow path resistance determining means for determining the flow path resistance of the ventilation flow path,
Optimal air volume and flow path determined by the optimal air volume determining means
The flow is determined based on the flow path resistance determined by the resistance determining means.
Determine the optimal rotation speed of the fan motor, and
Generates a speed command signal so that the speed is at the optimum speed.
Generated by the optimum rotational speed determining means and the optimal rotational speed determining means.
Speed command signal and the speed detected by the speed detection means.
The rotation speed of the fan motor is based on the rotation speed and the command rotation speed.
To control the duty ratio of the control pulse so that
Duty ratio control means, and the current calculation means
Output current detected by the detection means and duty ratio control
Information on the duty ratio controlled by the
The output current detected by the current detection means based on
By converting to the output current in the
The current flowing through the fan is calculated.
Motor speed can always be maintained according to the flow path resistance
You. Therefore, even if the flow path resistance changes, always the optimal combustion
Can be maintained.

According to the third aspect of the present invention, the duty ratio control means controls the duty ratio of the control pulse by adjusting the control voltage supplied to the power control means, and the current calculation means changes the control voltage. Vs, the minimum control voltage fan motor rotates Vl, the constant k, when the detected output current was Io by the current detection means, fa
The current I flowing through the down motor I = kIo / (Vs-Vl )
In the PWM driving method, the current flowing through the motor can be easily and accurately determined by detecting the output current of the rectifying / smoothing means regardless of the voltage fluctuation of the AC power.

[Brief description of the drawings]

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

FIG. 2 is a circuit block diagram of a motor drive unit provided in the motor control device according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram of power control means provided in the motor control device according to the first embodiment of the present invention.

FIG. 4 is a waveform diagram of a triangular wave obtained by a triangular wave oscillation circuit provided in the motor control device according to the first embodiment of the present invention.

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

FIG. 6 is a circuit diagram of a current detection unit provided in the motor control device according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating a relationship between a voltage detected by a current detection unit provided in the motor control device according to the first embodiment of the present invention and a rotation speed of a fan motor.

FIG. 8 is an explanatory diagram illustrating a relationship between a voltage detected by a current detection unit provided in the motor control device according to the first embodiment of the present invention and a rotation speed of a fan motor.

FIG. 9 is a flowchart illustrating an operation of the motor control device according to the first embodiment of the present invention.

FIG. 10 is an explanatory diagram illustrating a relationship among a current flowing through a fan motor controlled by a motor control device according to the first embodiment of the present invention, a rotation speed, and an air blowing amount.

FIG. 11 is an explanatory diagram illustrating a relationship between a current detected by a current detection unit provided in the motor control device according to the first embodiment of the present invention and a rotation speed of a fan motor.

FIG. 12 is a schematic configuration diagram of a PWM type motor control device.

FIG. 13 is a schematic configuration diagram of a PWA type motor control device.

FIG. 14 is an explanatory diagram of an abnormality determination area by abnormality determination means provided in the motor control device according to the first embodiment of the present invention.

FIG. 15 is a schematic configuration diagram of a hot water supply device including a motor control device according to a second embodiment of the present invention.

FIG. 16 is a flowchart illustrating an operation of the motor control device according to the second embodiment of the present invention.

FIG. 17 is a schematic configuration diagram of a main part of a motor control device according to a third embodiment of the present invention.

FIG. 18 is a schematic configuration diagram of a main part of a motor control device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 5 fan motor 6 sirocco fan 16 rectifying / 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 determination means 25 abnormality determination means 26 abnormality processing means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-70288 (JP, A) JP-A-5-91707 (JP, A) JP-A-3-143294 (JP, A) JP-A-1- 252819 (JP, A) JP-A-2-208414 (JP, A) JP-A-53-103524 (JP, A) JP-A-2-45344 (JP, U) JP-A-61-14799 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02P 5/00 H02P 7/00 F23N 3/08

Claims (3)

(57) [Claims] 1. An air blower disposed in an air flow passage of a combustor.
Supply power to the fan motor that rotates the fan
Rectifier that rectifies and smoothes AC power and outputs DC power in a motor control device that rotates the motor
It has a smoothing means and a PWM variable speed circuit, and is generated by this PWM variable speed circuit.
Based on the control pulse to be applied,
Switch the electric power to drive the fan motor
Power control means for supplying power as a motor, and rotation speed detection means for detecting the rotation speed of the fan motor
When current detecting means for detecting an output current of the rectifying smoothing means
And the rotation speed command signal and the rotation speed detected by the rotation speed detection means.
The rotation speed of the fan motor is commanded based on the rotation speed.
The duty ratio of the control pulse is adjusted so that
Duty ratio control means for controlling, and current calculation means for calculating a current flowing through the fan motor
And the current calculated by the current calculating means and the rotation speed detection.
The blast flow based on the rotation speed detected by the outlet means.
Flow path resistance determination means for determining the flow path resistance of the road, wherein the current calculation means is detected by the current detection means
Output current and the duty ratio control means.
The current based on the
The output current detected by the detection means is output in the PAM system.
The fan motor flows through
A motor control device for calculating a current flowing through the motor. 2. An air blower disposed in an air flow passage of a combustor.
Supply power to the fan motor that rotates the fan
Rectifier that rectifies and smoothes AC power and outputs DC power in a motor control device that rotates the motor
It has a smoothing means and a PWM variable speed circuit, and is generated by this PWM variable speed circuit.
Based on the control pulse to be applied,
Switch the electric power to drive the fan motor
Power control means for supplying power as a motor, and rotation speed detection means for detecting the rotation speed of the fan motor
When current detecting means for detecting an output current of the rectifying smoothing means
And the rotation speed command signal and the rotation speed detected by the rotation speed detection means.
The rotation speed of the fan motor is commanded based on the rotation speed.
The duty ratio of the control pulse is adjusted so that
Duty ratio control means for controlling, and current calculation means for calculating a current flowing through the fan motor
And determining the optimum air flow rate based on the combustion volume of the combustor.
Means for judging an appropriate air flow rate, detecting the current calculated by the current calculating means and detecting the rotation speed.
The blast flow based on the rotation speed detected by the outlet means.
Flow path resistance determining means for determining the flow path resistance of the road, and the optimal blowing amount determined by the optimal blowing amount determining means;
Based on the flow path resistance determined by the flow path resistance determining means.
Then, the optimum rotation speed of the fan motor is determined,
So that the rotation speed of the fan motor becomes the optimum rotation speed.
Supply the rotation speed command signal to the
An appropriate rotation speed determining means, wherein the current calculating means is detected by the current detecting means.
Output current and the duty ratio control means.
The current based on the
The output current detected by the detection means is output in the PAM system.
The fan motor flows through
A motor control device for calculating a current flowing through the motor. 3. A duty ratio control unit controls a duty ratio of a control pulse by adjusting a control voltage supplied to the power control unit. A current calculation unit sets the control voltage to Vs and rotates the fan motor. When the minimum control voltage is Vl, the constant is k, and the output current detected by the current detecting means is Io, the current I flowing through the fan motor is calculated based on the following equation 1. The motor control device according to claim 1 or 2, wherein (Equation 1)