JPH09137940A - Controlling device of fan motor of combustion equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out highly accurate detection of a normal/abnormal state of combustion without requiring a long time from a start of operation to ignition, and of the degree of the abnormal combustion at the time when the abnormal state of combustion is detected. SOLUTION: Checking of abnormal combustion by a determining part 19 is executed every time when a cumulative combustion time amounts to 10 hours on the occasion of post-purge. When the data on the aforesaid time in a storage part 11 reach 10 hours and continuous combustion is judged to be 5 minutes or more, detected values of the number of revolutions of a fan, a drive current and a drive voltage are read in, and when any two of these values are stable, the fan 5 is determined as being in a steady state. Thereafter a voltage corresponding to the maximum number of revolutions is applied to a fan motor, then the number of revolutions of the fan, the drive current and the drive voltage are read in and the drive voltage is controlled to be a prescribed value. In this state, the real number of revolutions of the fan at this time and the reference number of revolutions (of the initial number of revolutions) are compared with each other and, when difference between them is larger than a threshold, the combustion is determined as abnormal (clogging).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a fan motor control device for driving a fan for supplying air to a combustion device.

[0002]

2. Description of the Related Art Conventionally, in a combustion apparatus such as a gas water heater, when the operation is started (pre-purge), the rotation speed of a fan that supplies air to the burner is detected to cause clogging of an air supply filter (insufficient air supply amount). ) Is known, a device for stopping the combustion is known (Japanese Patent Laid-Open No. 63-18971).
No. 2). Also, during combustion, when the fan speed and its drive voltage and drive current are detected and the degree of abnormal combustion due to insufficient air supply is determined to be "small," operation continues and a warning is issued, and when "large," operation is performed. There is also known a device for taking a stop action (see Japanese Patent Laid-Open No. 5-196229).

[0003]

Generally, in order to perform highly accurate fan rotation speed detection, it is necessary to set the fan rotation speed in a high-speed rotation region and maintain it at a constant rotation speed.

By the way, in the apparatus disclosed in Japanese Patent Laid-Open No. 63-189712, the rotation speed of the fan is detected at the start of operation (that is, before combustion). Therefore, even if the clogging of the air supply filter is found, the combustion is immediately started. Since it is stopped, there is an advantage that abnormal combustion can be prevented.

However, in the above device, once the fan rotation speed is raised to the maximum rotation speed (for example, 3500 rpm) to detect the rotation speed, the rotation speed required for ignition (pre-purge rotation speed: 1500 rpm) is reached. Since it is configured to lower the temperature and shift to the ignition process, there is a problem that it takes a long time from the start of operation to the ignition. Also,
The rotation speed of the fan may be detected while the motor that drives the fan is not warmed up, and in that case, there is a problem in that accurate rotation speed detection cannot be performed.

On the other hand, in the device disclosed in Japanese Patent Laid-Open No. 5-196229, high disturbance is caused during combustion in which it is difficult to realize a stable state of the rotational speed of the fan, the drive voltage and the drive current. There is a problem in that it is not possible to accurately determine whether the combustion state is good or bad and how large or small the degree of deterioration of the combustion state is.

Therefore, an object of the present invention is to detect a normal / abnormal combustion state with high accuracy and to detect an abnormal combustion state without requiring a long time from the start of operation to ignition.
It is an object of the present invention to provide a fan motor control device for a combustion device capable of highly accurately detecting the degree of abnormal combustion.

[0008]

A fan motor control apparatus according to the present invention judges whether or not the control of the fan motor is stable, and when it is judged as stable as a result,
It is determined from the state of the fan motor whether abnormal combustion occurs. When the control of the fan motor is stable, it is determined whether the combustion is abnormal or not, so that the normal / abnormal combustion state can be detected with high accuracy.

Whether or not the control of the fan motor is stable is determined by, for example, fan drive current, fan drive voltage,
If any two of the fan rotational speeds are within a predetermined numerical value range for a predetermined time, it can be determined that the fan rotational speed is stable.

Alternatively, it may be determined that the control is stable when a predetermined time (generally, a time when the control is expected to be stable) has elapsed since the control of the fan motor was started.

Further, the determination as to whether or not the combustion is abnormal is performed, for example, by
It is possible to determine whether the combustion is abnormal or not based on the result of comparison between the fan rotation speed and a predetermined reference rotation speed while keeping the drive voltage of the fan motor constant.

Alternatively, it is also possible to determine whether or not the combustion is abnormal based on the result of comparison between the input power of the fan motor and a predetermined reference drive power with the fan rotation speed kept constant.

The control device of the present invention drives the fan motor in a rotation speed range higher than the fan rotation speed normally used during combustion, waits for the control to stabilize at that time, and determines whether abnormal combustion occurs. It is desirable to judge By making the determination in the high rotation speed range, the influence of noise and the like is reduced, and more accurate detection can be performed.

It is desirable that the timing of the determination is post-purge of the combustion device. In the case of post-purge, even if the fan motor is driven in the high rotation speed range, there is almost no delay in the start of combustion as in the case of pre-purge, and sufficient fan drive time can be secured, so control is possible. Since it can be reliably stabilized and the motor is sufficiently warmed, highly accurate detection is possible.

The above-described determination operation may be performed each time combustion is performed, but may be performed occasionally at appropriate intervals. For example, it is performed every time the usage amount of the combustion device (for example, the number of combustions, the combustion time, the elapsed time, etc.) increases by a certain amount. As described above, since the frequency of the abnormal combustion determination can be reduced within a necessary range by performing the determination at an appropriate interval, it is possible to reduce the number of times that the user feels inconvenient by performing the determination.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a fan motor control device in which the present invention is applied to a gas water heater.

The gas water heater is a water supply source (not shown).
Heat exchanger 1 for warming the water from the room to supply hot water to a hot water supply tap (not shown), a burner 3 for heating the heat exchanger 1, a fan 5 for supplying air to the burner 3, a fan 5 A combustion unit 9 having a fan motor (for example, a DC brushless motor) 7 for driving The fan 5 is provided with a rotation speed detector (not shown) for detecting the rotation speed thereof. In addition, the fan motor 7 has a current detection circuit for detecting its drive current,
And a voltage detection circuit (neither of which is shown) for detecting the drive voltage (applied voltage) thereof.
The water heater is a controller 23 for controlling each part of the water heater including the combustion unit 9, and an operation unit (not shown) for sending various commands such as a combustion start request and a combustion stop request to the controller 23. Control board 25 having the like
Also equipped with.

The controller 23 detects the drive current of the fan motor 7 based on the output from the rotation speed detector, the rotation speed detection unit 11 for detecting the rotation speed of the fan 5, and the output from the current detection circuit. And a voltage detection unit 15 that detects the drive voltage of the fan motor 7 based on the output from the voltage detection circuit.

The controller 23 stores in advance reference values for normal / abnormal determination of fan speed, normal / abnormal determination of fan motor drive current, and normal / abnormal determination of fan motor drive voltage, and hot water supply. It also includes a storage unit 17 for measuring the cumulative combustion time of the machine and accumulating the measured data. The reference value for normal / abnormal determination of fan speed (hereinafter referred to as the rotation speed reference value) is the fan speed when the combustion state is normal and the best, and the combustion state from normal to abnormal. It is the difference between the number of fan rotations at the time of transition (a threshold value for determining abnormal combustion). The same applies to the reference value for normal / abnormal determination of fan motor drive current (hereinafter referred to as drive current reference value) and the reference value for normal / abnormal determination of fan motor drive voltage (hereinafter referred to as drive voltage reference value). is there.

The controller 23 compares the detection result of the rotation speed with the reference value of the rotation speed, the comparison result of the detection value of the drive current with the reference value of the drive current, the detection value of the drive voltage with the reference value of the drive voltage. The determination unit 19 that determines whether or not the heat exchanger 1 or the air supply filter is clogged with soot or the like (abnormal combustion) is also provided based on the comparison result. The controller 23 further includes an operation unit 21 that controls the operation of each unit of the water heater such as changing the rotation speed of the fan motor 7 based on the output from the determination unit 19.

Next, the control operation of the above configuration will be described with reference to the flowchart of FIG.

In the control operation described below, the water heater is operated (combusted) and then stopped (that is, post-purge).
It is executed when you move to.

First, when there is a request to stop the operation of the water heater (step S1), the determination section 19 determines that the cumulative combustion time is 10
Every time the time is reached, the accumulated combustion time data in the storage unit 17 is read out and it is checked whether the time has reached 10 hours in order to detect the clogging of the air supply filter or the like and perform a series of control related thereto (step S2). As a result, if it is determined that 10 hours have been reached, it is checked whether or not the water heater has continuously burned for 5 minutes or more (that is, whether or not the fan motor 7 is sufficiently warmed) (step S3).

When it is determined that the time is 5 minutes or more (step S3), in order to detect the rotation speed of the fan 5 with high accuracy,
Maximum number of revolutions (number of revolutions for determining whether abnormal combustion occurs) 3500rp from the number of revolutions (1500 rpm) at ignition
In order to raise it to m, the drive voltage of the fan motor 7 is controlled to a value commensurate with the maximum rotation speed (step S4).

Next, the fan rotation speed detection value, the fan motor drive current detection value, and the fan motor drive voltage detection value are read, and the fan rotation speed of the fan motor 7 is increased based on these detection values. It is checked whether the driving state has deviated from the steady state (step S5). Here, whether or not the control state of the fan 5 is a steady state is a state in which any two of the detected values are stable for a predetermined time (for example, the rotational speed stability is 10 seconds or more when the rotational speed fluctuation is within ± 35 rpm). If the drive current is stable,
The current fluctuation is within ± 0.05 A for 10 seconds or more)).

Alternatively, a time (for example, 40 seconds from the time of the operation stop request) estimated in advance from the time when the operation stop request is input to the time when any two of the detected values shift to the stable state has elapsed. Whether or not it is in the steady state may be determined depending on whether or not it is done. Since the time required to reach a steady state varies depending on how the motor warms up, the above estimated time is the operating state of the water heater before the operation stop request is input (for example, the operating time immediately before the operation stop request is input or , The time from the last fan drive stop to the current fan drive start, etc.) can be made variable.

Therefore, in step S5, the length of time during which any two of the detected values remain in the stable state or the length of time during which any two of the detected values transition to the stable state is determined. By checking either one, it is determined whether or not the drive state of the fan 5 is a steady state. As a result of the above check, when it is determined that the engine is in a steady state (step S5), the fan rotation speed, the fan motor drive current, and the fan motor drive voltage are read to determine whether or not there is clogging due to soot (= abnormal combustion) At the same time, the cumulative combustion time data in the storage unit 17 is erased (step S6).

For example, when it is determined in step S5 that the fan rotation speed and the fan motor drive current are stable, the fan motor drive voltage is controlled to the constant value set in step S4, and abnormal combustion occurs. The determination target value of the fan rotation speed for determining whether or not is determined by the following formula.

Fan rotation speed determination target value = | Fan initial rotation speed−Fan actual rotation speed | ...

Here, the initial rotation speed of the fan means the rotation speed of the fan when the combustion device is in a normal state, such as the rotation speed of the fan when the combustion device is shipped from the factory. The actual fan rotation speed is the fan rotation speed detected by the rotation speed detector described above.

Next, this judgment target value is compared with the rotation speed reference value in the storage unit 17, and as a result of this comparison, when it is judged that the judgment target value is larger than the rotation speed reference value (step S
6), it is determined to be clogged (abnormal combustion) (step S
7).

Here, when the fan motor drive voltage is constant, if there is soot or clogging in the heat exchanger 1, the air supply filter, etc., the greater the degree of clogging, the more air does not flow. (Torque) decreases. Therefore, the fan rotation speed tends to increase further than 3500 rpm, and if the increase is larger than the rotation speed reference value, it is determined that the fan is clogged (air amount is insufficient, that is, abnormal combustion).

The controller 21 determines in step S1.
When it is determined that there is no operation stop request in, of course,
The combustion operation of the water heater is continued as it is. In addition, when it is determined in step S2 that the cumulative combustion time is less than 10 hours, when it is determined in step S2 that the cumulative combustion time has reached 10 hours but continuous combustion is less than 5 minutes in step S3, and If it is determined in S5 that the fan 5 is not in a steady state, the processes in and after step S6 are not performed.

As described above, according to the embodiment of the present invention, after the request for stopping the operation of the gas water heater, the continuous combustion is performed for 5 minutes or more each time the cumulative combustion time reaches 10 hours. Since the fan motor 7 is driven in a high rotation speed range to perform the abnormal combustion check at the time of the occurrence of the abnormal combustion check, the number of abnormal combustion checks can be reduced unlike the case of performing the abnormal combustion check every combustion. . Therefore, it is possible to reduce the number of times noise is generated by rotating the fan motor 7 at a high speed, and thus to reduce the number of times the user feels uncomfortable.

Further, since the abnormal combustion check is carried out at the time of post-purge and in the steady state of the fan motor 7, it is supposed to be carried out at the start of the operation of the gas water heater like the device of Japanese Patent Laid-Open No. 63-189712. Unlike, there is no problem that it takes a long time from the start of operation to ignition,
In addition, the problem that accurate rotation speed detection cannot be performed does not occur.

Further, since the abnormal combustion check is carried out during the post-purge, there are many disturbances and the fan rotation speed, the fan motor drive voltage, and the fan motor drive current are stable as in the device of Japanese Patent Laid-Open No. 5-196229. Unlike the one that is performed during combustion, which is difficult to achieve, it is possible to perform highly accurate determination of the combustion state, for example, to determine whether the degree of deterioration of the combustion state is large or small.

It should be noted that the above content is only related to one embodiment of the present invention, and does not mean that the present invention is limited to the above content.

For example, a method of controlling the fan rotation speed to a constant value (3500 rpm) by the controller 23 to check the input power of the fan motor 7 is adopted, and this method is used to judge whether clogging (abnormal combustion) has occurred. You may go.

That is, when it is determined in step S5 that the fan motor drive current and the fan motor drive voltage are stable, the fan rotation speed is constant (35).
The control target value of the fan motor drive current for determining whether or not the combustion is abnormal is obtained by the following equation under the control of 100 rpm). Alternatively, the determination target value of the fan motor drive voltage for determining whether the combustion is abnormal is calculated by the following formula.

Fan motor drive current judgment target value = | Fan motor initial drive current value−Fan motor actual drive current value | ...

Fan motor drive voltage determination target value = | Fan motor initial drive voltage value−Fan motor actual drive voltage value | ...

Here, the initial drive current value of the fan motor means the fan motor drive current value when the combustion device is in a normal state, such as the fan motor drive current value when the combustion device is shipped from the factory. is there. The actual drive current value of the fan motor is the fan motor drive current value detected by the current detection circuit described above.

Similarly, the initial drive voltage value of the fan motor means the fan motor drive voltage value when the combustion device is in a normal state, such as the fan motor drive voltage value when the combustion device is shipped from the factory. is there. The actual drive voltage value of the fan motor is the fan motor drive voltage value detected by the voltage detection circuit described above.

Next, the judgment target value of the fan motor drive current is compared with the drive current reference value in the storage unit 17, and when it is judged that the judgment target value is larger than the drive current reference value (step S6). ), It is determined to be clogged (abnormal combustion) (step S7). Similarly, when the determination target value of the fan motor drive voltage is compared with the drive voltage reference value in the storage unit 17, and as a result, it is determined that the determination target value is larger than the drive voltage reference value (step S6), It is determined to be clogged (abnormal combustion) (step S7).

In this case, as described above, as the torque of the fan 5 decreases, the fan rotation speed increases. Therefore, in order to maintain the fan rotation speed at 3500 rpm, the driving power is reduced in accordance with the decrease in the work amount. It will have to be done. Therefore, if the reduction amount of the drive power, that is, the determination target value of the drive current is larger than the drive current reference value, or the determination target value of the drive voltage is larger than the drive voltage reference value, clogging (abnormal combustion) occurs. It will be judged.

[0047]

As described above, according to the present invention,
Highly accurate detection of normal / abnormal combustion conditions is possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of a water heater as one embodiment of a combustion device of the present invention.

FIG. 2 is a flowchart showing a control operation of the controller of FIG.

[Explanation of symbols]

 1 Heat Exchanger 3 Burner 5 Fan 7 Fan Motor 9 Combustion Section 11 Rotation Speed Detection Section 13 Current Detection Section 15 Voltage Detection Section 17 Storage Section 19 Judgment Section 21 Operating Section 23 Controller 25 Control Board

Front Page Continuation (72) Inventor Toru Tsuruta 43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Nihon Yupro Co., Ltd. (72) Inventor Hiroshi Munemura 43-1, Uozakihama-cho, Higashinada-ku, Kobe, Hyogo Nihon Within Yupro Corporation

Claims (9)

[Claims] 1. A controller for a fan motor that drives a fan for supplying air to a combustion device, comprising: a determining unit that determines whether or not the control of the fan motor is stable; And a determination unit that determines whether or not abnormal combustion has occurred from the state of the fan motor when it is determined that the fan motor control apparatus for the combustion device. 2. The fan motor control device for a combustion device according to claim 1, wherein the determination unit determines that any two of the fan drive current, the fan drive voltage, and the fan rotation speed are within a predetermined numerical value range for a predetermined time. A fan motor control device for a combustion device, wherein the control is determined to be stable. 3. The fan motor control device for a combustion device according to claim 1, wherein the determination unit determines that the control is stable when a predetermined time has elapsed from the start of control of the fan motor. A fan motor control device for a combustion device characterized by the above. 4. The fan motor control device for a combustion device according to claim 1, wherein the determination means determines a comparison result between the fan rotation speed and a predetermined reference rotation speed in a state in which the drive voltage of the fan motor is constant. A fan motor control device for a combustion device, characterized in that it is determined based on abnormal combustion. 5. The fan motor control device for a combustion device according to claim 1, wherein the determination means determines a comparison result between the input power of the fan motor and a predetermined reference drive power in a state where the fan rotation speed is constant. A fan motor control device for a combustion device, characterized in that it is determined based on abnormal combustion. 6. The fan motor control device for a combustion device according to claim 1, wherein the determination of the abnormal combustion by the determination means is performed every time the cumulative usage amount of the combustion device reaches a predetermined time. Combustion device fan motor controller. 7. The fan motor control device for a combustion device according to claim 1, further comprising a fan motor drive means for driving the fan motor in a rotation speed range higher than a fan rotation speed normally used during combustion. A fan motor control device for a combustion device, wherein the determination means determines whether or not abnormal combustion occurs when the fan motor is driven in the high rotation speed range. 8. The fan motor control device for a combustion device according to claim 7, wherein the fan motor is driven by the fan motor driving means in a high rotation speed range during post-purge of the combustion device. A fan motor control device for a combustion device. 9. The fan motor control device for a combustion device according to claim 1, wherein the determination by the determination means is performed during post-purge of the combustion device.