JP2003161496A - Control method for air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the correct start/stop timing of defrost operation by eliminating the influence of change in condition of heating operation or natural wind on the number of rotations of a fan. <P>SOLUTION: To correctly detect change in the number of rotations of a fan motor caused by frost formation on fins of a heat exchanger, the following processing is performed: Firstly, the fan motor is driven in fixed voltage (ST11), and the driven-time rotational number is stored (ST12); secondary, the not-driven-time rotational number at a time where the fan motor is not driven is detected (ST13). When the not-driven- time rotational number is approximately zero (ST14-Y), the determination is made to be in a calm state, so that the driven-time rotational number is used as it is. When the not-driven-time rotational number is not approximately zero (ST14-N), the not- driven-time rotational number is stored (ST15) and the above processing is repeated by predetermined times. When the repetition is completed (ST10-Y), the driven-time rotational number is corrected by the not-driven-time rotational number (ST16), the mean value is calculated (ST17), the calculation result is decided as a final driven-time rotational number, a reference rotational number is compared to the driven rotational number, and then the determination is made about the defrost operation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to start / stop of defrosting operation.
The present invention relates to an air conditioner control method for determining a stop timing.

[0002]

2. Description of the Related Art Conventionally, a control method for determining a start / stop timing of a defrosting operation in an air conditioner is shown in FIG.
This is a method of controlling the defrosting operation by detecting the change in the rotation speed of the fan motor due to frost formation on the fins (not shown) of the heat exchanger, using the air conditioner configured by the block diagram of . The air conditioner of FIG. 1 includes an indoor unit 1 and an outdoor unit 2. The outdoor unit 2 includes a compressor driving unit 4 that drives the compressor 3, a fan motor 5 including a fan that blows outside air to the heat exchanger, and a fan motor driving unit 6 that drives the fan motor 5.
A rotation speed detection sensor 7 for detecting the rotation speed and the rotation direction of the fan motor 5, a sensor input unit 9 for inputting a signal from the rotation speed detection sensor 7 and sending it as a rotation speed value to the control unit 8, Memory unit 10 for temporarily storing the number of revolutions
And a control unit 8 that controls each unit in the outdoor unit 2. Further, the control unit 8 is connected to the indoor unit 1,
The indoor unit 1 is configured to transmit a driving instruction from the indoor unit 1 and the state of the outdoor unit 2 to the indoor unit 1. It should be noted that description and illustration of a heat exchanger, a refrigerant circuit, and the like, which are not directly related to the control method of the present application, are omitted.

A control method for determining the timing for carrying out the defrosting operation in the above configuration will be described. When the outdoor unit 2 starts the heating operation according to the instruction of the indoor unit 1, the heat exchanger of the outdoor unit 2 absorbs the heat of the outside air and performs the heat exchange operation of sending the heat to the indoor unit 1. Therefore, the temperature around the heat exchanger becomes lower than the outside air. At this time, in order to increase the efficiency of heat exchange, the fan motor 5 arranged near the heat exchanger is rotated, and the outside air around the heat exchanger is circulated by the fan fixed to the fan motor 5. When the humidity of the outside air is high, the frost forms on the fins of the heat exchanger due to the circulation of this outside air, and the air passage of the fins narrows
The efficiency of heat exchange deteriorates. Therefore, the refrigerant circuit is reversed and the defrosting operation is performed to melt the frost that has accumulated on the heat exchanger.
Since the heating function is temporarily stopped during this defrosting operation, accurate frosting detection is required to prevent defrosting operation as much as possible.

As one of the methods for detecting the frost formation, there is a method for detecting a change in the rotation speed of the fan motor 5. This is a method of detecting the timing when the air passage of the fin is narrowed due to frosting and the circulation of the outside air is deteriorated, the load of the fan motor 5 is increased, and as a result, the rotation speed of the fan motor 5 changes. When the control unit 8 starts the heating operation,
The rotation speed of the fan motor 5 is detected by the rotation speed detection sensor 7, and is stored as a reference rotation speed in the memory unit 10 via the sensor input unit 9. At this time, the heating operation has just started, and the fins of the heat exchanger have not been frosted yet. After that, the control unit 8 continuously operates the current fan motor 5
The drive rotation speed, which is the rotation speed of, is detected and the reference rotation speed and the drive rotation speed are compared. For example, when the driving rotation speed is lower than the reference rotation speed by 10% or more, it is determined that frost has formed, and the defrosting operation is started. In addition, the drive rotation speed is continuously detected even after the defrosting operation is started, and if the drive rotation speed becomes almost the same as the reference rotation speed, it is determined that defrosting is completed, and the defrosting operation is stopped and the heating operation is restarted. .

However, the fan motor 5 during the heating operation has its rotation speed finely controlled according to the heating operation situation which changes every moment according to the temperature change in the room. Therefore, it is necessary to detect an accurate rotation speed change due to frost formation. Was difficult. Further, since the outdoor unit 2 is located outdoors, the rotation speed of the fan is affected by the natural wind, and the accurate start / end timing of the defrosting operation cannot be detected.

[0006]

SUMMARY OF THE INVENTION The present invention solves the problems described above, eliminates the influence of changes in the heating operation status and the fan speed on the fan rotation speed, and provides accurate start / end timing of defrosting operation. It is an object of the present invention to provide a method for controlling an air conditioner that can detect air pollution.

[0007]

In order to solve the above problems, the present invention detects the number of rotations of a fan motor of an outdoor unit of an air conditioner to detect heat generated by frost during heating operation of the air conditioner. In order to remove the frost on the exchanger, the reference rotation speed that is measured in advance at a predetermined time and is the fan motor rotation speed when it is not frosted is compared with the current drive rotation speed that is the fan motor rotation speed. However, the defrosting operation is started when the drive rotational speed is smaller than the reference rotational speed by a predetermined value or more, and is removed when the difference between the reference rotational speed and the drive rotational speed is a predetermined value or less. In an air conditioner control method for stopping a frost operation, the rotation speed of the fan motor when the fan motor is not driven immediately after the drive rotation speed is detected and the drive of the fan motor is stopped. Detects the undriven speed, or Immediately after detecting the dynamic rotational speed, the fan motor is driven to detect the drive rotational speed, and the reference rotational speed and the drive rotational speed are compared when the undriven rotational speed is equal to or lower than a predetermined rotational speed. .

The reference rotation speed and the drive rotation speed are the rotation speed of the fan motor when driven with a predetermined voltage.

When the undriven rotational speed is equal to or higher than a predetermined rotational speed, the drive rotational speed and the undriven rotational speed are alternately detected a predetermined number of times.

Further, an average rotation speed which is an average value of the plurality of drive rotation speeds is calculated, and the defrosting operation is performed only when the average rotation speed is smaller than the reference rotation speed by a predetermined rotation speed.

Further, the rotation direction of the fan motor is simultaneously detected at the time of detecting the undriven rotational speed, and the value of the driven rotational speed is corrected using the undriven rotational speed corresponding to the rotational direction.

Further, the driving rotation speed detected when the undriving rotation speed is equal to or lower than a predetermined rotation speed is detected a plurality of times, and the driving rotation speed is arithmetically averaged.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a control method for an air conditioner according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an air conditioner according to the present invention, the configuration of which is the same as that of the conventional technique, and therefore the description thereof is omitted, and the accurate start / end of defrosting operation, which is a feature of the present application An air conditioner control method capable of detecting timing will be described.

FIG. 2 is a flow chart showing an embodiment of heating operation processing using the defrosting operation control method for an air conditioner according to the present invention. Further, FIG. 3 is an embodiment showing a control flow chart for detecting the drive rotational speed which is the current rotational speed of the fan motor 5 necessary for controlling the defrosting operation,
FIG. 4 is a table showing the data of the detected rotation speed stored in the memory unit 10.

The control process of FIG. 2 represents a heating operation (including a defrosting operation) performed by the control unit 8 in response to an instruction from the indoor unit 1. First, the heating operation is started (ST0), and it is checked whether a certain time, for example, 30 minutes has passed (ST
1), if nothing has passed, do nothing and wait (ST1-
N). This is because defrosting does not occur for a certain period of time from the start of the heating operation, and thus the defrosting operation is not performed during this period.
When one hour has passed (ST1-Y), the current frosted state is detected, so that the drive rotational speed, which is the current rotational speed of the fan motor, is detected (ST2). The drive rotation speed is basically the rotation speed when the fan motor 5 is driven with a predetermined voltage, but may be subjected to various corrections described later. This processing is a characteristic part of the present application, and a detailed flowchart will be presented in FIG. 3 and detailed description will be given later.

Next, the detected drive rotational speed is compared with a reference rotational speed, which was previously determined at the time of design and detected when frost was not formed and when there was no natural wind, for example, 22 rotations (ST3). If a predetermined difference in which the drive rotation speed and the reference rotation speed are substantially the same, for example, within two rotations, it is determined that there is no frost formation, and nothing is done and a certain time elapses (ST3-N). If the drive rotation speed is smaller than the reference rotation speed by a difference of two or more rotations (ST3-
Y) It is judged that there is frost, and the heating operation is stopped (ST4),
Defrosting operation is performed for a fixed time, for example, 10 minutes (ST
5). Next, the drive rotation speed is detected again to detect the current frost formation state (ST6). Then, the detected drive rotation speed is compared with the reference rotation speed (ST7). If the driving rotation speed is smaller than the reference rotation speed by a difference of two rotations or more, it is determined that frost is still formed, and the defrosting operation is performed again for 10 minutes (S.
T7-Y). If the predetermined difference in which the drive rotation speed and the reference rotation speed are substantially the same is within 2 rotations, it is determined that the frost has already melted (ST7-N), the heating operation is restarted (ST8), and then a series of operations is started from ST1. Repeat the operation.

Next, a control method which is a characteristic part of the present application and which detects the drive rotational speed for judging the current frosting state will be described with reference to the flowchart of FIG. This control is shown in Figure 2.
This is a process commonly used in ST2 and ST6 of the flowchart of 1. and is used for accurately detecting the presence or absence of frost in consideration of the natural wind. First, in order to detect the stop timing of the natural wind, the drive rotation speed detection processing is performed a plurality of times.
Therefore, it is determined whether or not the drive rotation speed detection processing has been performed a designated number of times, for example, three times (ST10). If it is less than the specified number of times (ST10-N), a predetermined voltage is applied to the fan motor 5 from the fan motor drive unit 6 according to an instruction from the control unit 8, and the fan is rotated for a fixed time, for example, 10 seconds (ST11). . At this time, the rotation speed of the fan motor 5 is simultaneously counted by the rotation speed detection sensor 7, and the result is stored in the drive rotation speed column of the memory unit 10 shown in FIG. 4 (ST12). During the driving of the fan motor 5, the rotation speed is detected by not performing the feedback related to the rotation speed and the torque.

Next, after the fan motor 5 is stopped, the fan motor 5 is expected to be completely stopped, for example, 5 seconds, and the undriven rotation which is the current rotation speed of the fan motor 5 is set. The number is detected (ST13). At this time, the rotation direction of the fan motor 5 is also detected at the same time. When the normal direction in which the fan motor 5 rotates is forward rotation and the reverse direction is reverse rotation, a minus sign is added to the value of the undriven rotation speed detected during reverse rotation. If the detected undriven rotational speed is a predetermined rotational speed that is almost zero, for example, less than ± 1 rotation, it is determined that there is almost no wind (ST14-Y), and the rotational speed value stored in the drive rotational speed column. The memory unit 10 shown in FIG.
It is stored in the field of the final drive rotation number of (ST19), and this processing is exited. If the undriven rotation speed is ± 1 rotation or more (ST
14-N) The value of the rotation speed is stored in the column of the undriven rotation speed of the memory unit 10 shown in FIG. 4 (ST15), and the processing from ST10 is repeated again. The driving rotation speed and the non-driving rotation speed in FIG. 4 are stored in the columns corresponding to the first to third rotation speed detections, respectively.

When the number of times of the drive rotational speed detection processing is checked three times (ST10-Y), the drive rotational speed value is corrected by the value of the undriven rotational speed (ST16). As described above, if the windless state can be detected even once, the detected drive rotational speed can be set as the final drive rotational speed, but if the windless state cannot be detected even after detecting three times, there is continuous wind. Therefore, it is considered that the detected drive speed is affected by wind.
Therefore, the non-driving speed is subtracted from the driving speed detected at each time, and stored in the column of the corrected speed. That is, if the value of the undriven rotation speed is forward rotation, the driving rotation speed is increased by the normal wind, and therefore the processing for subtracting the undriven rotation speed is performed. Further, in the case of headwind, the value of the undriven rotational speed is added with a minus sign as described above, and as a result, it is possible to add and correct the rotational amount in which the driven rotational speed is decreased due to the headwind. . Although the undriven rotational speed is simply subtracted here for the sake of explanation, it is more accurate if the relationship of the change in the driven rotational speed with respect to the undriven rotational speed is investigated at the time of design and the undriven rotational speed is further corrected. The corrected rotation speed is obtained.
Next, the average value of each correction rotation speed is calculated (ST17), the calculated average correction rotation speed is stored in the field of the final drive rotation speed (ST18), and this processing is exited.

The memory unit 10 stores each of the detected rotational speeds, and an example thereof is the table of FIG. In this example, the number of drive revolutions and the number of non-drive revolutions are detected by 3 for each.
It is performed once, and each is stored as shown in FIG. The value of the second non-driving speed is "-2", which means that it has made two revolutions due to head wind, and the driving speed "19" detected immediately before this is affected by this. It is believed that In addition, the number of rotations other than two is positive because the number of undriven rotations is positive, and is therefore affected by normal wind (normal rotation). Therefore, by performing the above-mentioned correction (driving speed-undriving speed) every time, the driving speed in a pseudo-windless state is calculated as the corrected speed. Furthermore, the average value of each corrected rotation speed is stored as the final drive rotation speed. In this example, the final drive speed value is "1".
According to the control of the flow chart of FIG. 2, the reference rotational speed is "22", which is "2.7" lower than the reference rotational speed, and there is a difference of two or more rotations. Be the target.

By calculating and using the average value of the corrected rotational speeds in this way, the rotational speed measurement error can be reduced even when the natural wind speed is constantly changing.
Further, since the driving rotation speed and the non-driving rotation speed are detected a plurality of times, the probability of detection of a windless state is improved and more accurate detection is possible. It should be noted that, in this embodiment, the non-driving speed is detected after the driving speed is detected, but the same effect can be obtained by reversing this order. Further, a more accurate drive rotation speed can be detected by detecting the drive rotation speed detected a plurality of times when the undriven rotation speed is equal to or lower than the predetermined rotation speed and obtaining the average of the drive rotation speeds.

As described above, the detection of the rotation speed of the fan motor is separated from the normal heating operation, the rotation is performed at a predetermined voltage, and the rotation speed and torque control feedback to the fan motor are removed to detect the rotation speed. It is possible to detect an accurate change in the number of revolutions. Furthermore, since the timing when there is no natural wind can be specified by detecting the rotation speed of the fan motor when the drive of the fan motor is stopped, it is possible to detect an accurate change in the rotation speed due to frost formation.

[0023]

As described above, according to the air conditioner control method of the present invention, when the fan motor is not driven immediately after the drive speed is detected and the drive of the fan motor is stopped. Of the fan motor rotation speed, which is the undriven rotation speed, or immediately after detecting the undriven rotation speed,
The fan motor is driven to detect the drive rotation speed, and when the undriven rotation speed is equal to or lower than the predetermined rotation speed, the reference rotation speed and the drive rotation speed are compared to eliminate the influence of natural wind to eliminate the influence of the fan motor. Since the change in the rotation speed can be detected, it is possible to accurately detect the start / stop timing of the defrosting operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional embodiment and an embodiment of a configuration of an air conditioner common to the present invention.

FIG. 2 is a flowchart showing an example of a heating operation process using the defrosting operation control method for an air conditioner according to the present invention.

FIG. 3 is an embodiment showing a control flow chart for detecting a drive rotation speed according to the present invention.

FIG. 4 is a table showing rotation speed data stored in a memory unit.

[Explanation of symbols]

1 Indoor unit 2 outdoor unit 3 compressor 4 Compressor drive 5 fan motor 6 Fan motor drive 7 Rotation speed detection sensor 8 control unit 9 Sensor input section 10 memory section

Claims (6)

[Claims] 1. A fan motor of an outdoor unit of an air conditioner is detected in rotation speed, and is measured at a predetermined time in advance to remove frost on a heat exchanger that is frosted during heating operation of the air conditioner. Then, a reference rotation speed that is the fan motor rotation speed when not frosting is compared with a drive rotation speed that is the current fan motor rotation speed, and the drive rotation speed is equal to or more than a predetermined value from the reference rotation speed. In the control method of the air conditioner, the defrosting operation is started when the value is small, and the defrosting operation is stopped when the difference between the reference rotation speed and the drive rotation speed is a predetermined value or less. Immediately after stopping the drive of the fan motor by detecting the number of revolutions, the undriven revolution speed which is the revolution speed of the fan motor when the fan motor is not driven is detected, or the undriven revolution speed is detected. Immediately after that, drive the fan motor Wherein detecting the drive speed and the control method of an air conditioner undriven speed is characterized by being obtained by comparing the reference speed and the drive rotational speed when the following predetermined rotational speed Te. 2. The control method for an air conditioner according to claim 1, wherein the reference rotation speed and the drive rotation speed are rotation speeds of the fan motor when driven at a predetermined voltage. 3. The driving speed and the non-driving speed are alternately detected a predetermined number of times when the undriving speed is equal to or higher than a predetermined speed.
Or the control method of the air conditioner according to claim 2. 4. An average rotation speed that is an average value of a plurality of drive rotation speeds is calculated, and the defrosting operation is performed only when the average rotation speed is smaller than the reference rotation speed by a predetermined rotation speed. The control method of the air conditioner according to claim 3. 5. The rotation direction of the fan motor is detected at the same time when the undriven rotation speed is detected, and the value of the driven rotation speed is corrected by using the undriven rotation speed corresponding to the rotation direction. The method for controlling an air conditioner according to claim 4, wherein. 6. The method according to claim 1, wherein the drive rotational speed detected when the undriven rotational speed is equal to or lower than a predetermined rotational speed is detected a plurality of times, and the drive rotational speed is arithmetically averaged. Air Conditioner Control Method