JPH06288602A - Air conditioner - Google Patents

Abstract

PURPOSE:To keep indoor environment in a good state by suppressing local room temperature variation even if overload function is being operated due to extremely low outdoor temperature when room temperature is controlled by an air conditioner. CONSTITUTION:An air conditioner calculates an operation frequency code of a compressor 5 constituting a refrigerating cycle according to both a room temperature detected by a room temperature detecting means 3 and a set temperature set by a remote control setting means 4, and the inverter control of the compressor 5 is effected according to a frequency value in an operation frequency table corresponding to the operation frequency code. The operation frequency table 7a for an outdoor unit control means 7 is constituted of first to third operation frequency tables respectively having different operation frequency values and operation frequency intervals. As the temperature detected by an outdoor temperature detecting means 6 becomes lower, the operation frequency tables having the smaller operation frequency values and smaller operation frequency intervals are selected. By using the above selected operation frequency table the operation frequency code from the indoor unit control means 1 is converted to the operation frequency value of the compressor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner of an inverter type, which is capable of maintaining a stable room temperature even during a heating load protection operation during room temperature control.

[0002]

2. Description of the Related Art An inverter type air conditioner has, for example, a configuration shown in FIG. 3 and has an indoor unit control section 1 for controlling an indoor unit.
An outdoor unit controller 2 for controlling the outdoor unit, an indoor temperature detector 3 for detecting the indoor temperature (room temperature), a remote controller setting unit 4 for setting the room temperature by the room temperature control, and a refrigeration cycle. It is provided with a compressor 5.

When controlling the room temperature in the air conditioner having the above-mentioned structure, the indoor unit control section 1 detects the temperature difference between the room temperature (Tr) and the set temperature (Ts) by the internal calculation section 1a and responds to this temperature difference. The operating frequency code of the compressor 5 or the number of steps of the operating frequency code is used as the outdoor unit control unit 2
Call.

The outdoor unit control unit 2 on the outdoor side receives the operating frequency code, converts it to the operating frequency value of the compressor 5 by referring to the internal operating frequency table 2a, and at the same time, converts the operating frequency value of the compressor 5. Inverter control. In addition,
The operating frequency table 2a has, for example, the contents shown in Table 1 below. The operating frequency code from the indoor unit control unit 1 is hexadecimal data, and the outdoor unit control unit 2 transmits the hexadecimal data to the compressor 5 Convert to the operating frequency value of.

[0005]

[Table 1]

During the heating operation, the room temperature is low and the room temperature (T
When the temperature difference (Tr-Ts) between r) and the set temperature (Ts) is large, the operating frequency code transmitted from the indoor unit control unit 1 is large, that is, the operating frequency of the compressor 5 is increased, and thus the indoor frequency is increased. The temperature of can be raised quickly. When the room temperature is stable, the temperature difference (T
r-Ts) is small, the operating frequency code transmitted from the indoor unit control unit 1 is small, that is, the operating frequency of the compressor 5 is lowered, so that the room temperature does not change suddenly.
Room temperature can be stabilized.

[0007]

By the way, at the time of controlling the room temperature of the air conditioner, for example, in the heating operation in a state where the outside air temperature is relatively high (overload state),
The operating current with respect to the operating frequency of the compressor 5 becomes relatively higher than usual, and the protection function (current release) becomes easy to operate. Then, when the operating current exceeds a predetermined value, the current release operates and the operating frequency of the compressor 5 is switched to a value considerably lower than the instruction operating frequency code from the indoor unit control unit 1, so that the room temperature deteriorates. Will be lost.

When the heating operation is performed for a long time in the heating overload state, the pressure on the high-pressure side in the refrigeration cycle gradually rises, which causes the temperature of the indoor heat exchanger to rise and the indoor unit control section 1 to overheat. The load protection function operates. In this case, as shown in FIG. 4, the temperature of the indoor heat exchanger has reached a predetermined value (operating value; for example, 54 ° C.) or more so that the heating operation can be continued as much as possible while suppressing the pressure increase on the high pressure side. At this time, the operation of the overload protection function causes the indoor unit controller 1 to
The operating frequency code transmitted from the device is reduced, and when the temperature falls below a predetermined value (operating value; 50 ° C), the overload function is released. During the operation of the overload protection function, the operating frequency code of the compressor is 5 (H) when it is 6 (H) or more, and 1 step / 70 seconds when it is 3 (H) to 5 (H). (Lower by 1 (H) every 70 seconds), 1
It is set to 0 (H) when it is (H) and 2 (H).

However, as is clear from Table 1 above, since the difference in the operating frequency value between steps in the operating frequency code (frequency value interval) is wide, the operation of the overload protection function as shown in FIG. 5 is performed. The release is easy to repeat, and the operating frequency of the compressor 5 during this repetition varies greatly. Moreover, the more frequently it is repeated,
The fluctuation of the operating frequency is large and the fluctuation range of the room temperature is large, and the comfortability is deteriorated due to the deterioration of the room temperature.

The present invention has been made in view of the above problems, and an object thereof is to suppress deterioration of room temperature, suppress fluctuation of room temperature, and improve comfort even during the protective function operation at room temperature control. An object of the present invention is to provide an air conditioner that can be designed.

[0011]

To achieve the above object, the present invention calculates an operating frequency code of a compressor constituting a refrigeration cycle based on at least an indoor temperature and a set temperature, and at the same time, the operating frequency code. In an air conditioner in which a compressor is inverter-controlled with a frequency value of an operating frequency table corresponding to, a plurality of operating frequency tables for converting the operating frequency code into the operating frequency value of the compressor are provided, and the plurality of operating frequency tables are provided. The operating frequency table has different operating frequency values to be converted, one of the plurality of operating frequency tables is selected based on the temperature detected by the outside air detecting means, and the operating frequency table is selected with reference to the selected operating frequency table. Convert the calculated operating frequency code to the operating frequency value of the compressor, and compress the same based on the converted operating frequency. And summarized in that which is adapted to control.

[0012]

With the above configuration, when the detected outside air temperature is high and the overload protection function is easy to operate, the operating frequency value to be converted among the plurality of operating frequency tables is small on the outdoor unit side. An operating frequency table having a small interval of operating frequency values is selected. Then, the operating frequency code transmitted from the indoor unit side is converted into the operating frequency value of the compressor using the selected operating frequency table.

As a result, the protection function (current release) becomes difficult to operate, and the pressure on the high pressure side in the refrigeration cycle gradually rises. Even when the overload protection function operates in the indoor unit controller 1, the above selection is made. Since the interval between the operating frequency values in the operating frequency table is small, it becomes difficult for the room temperature to reach the release value of the overload protection function, and the repetition of the operation and release of the overload protection function does not occur frequently. Therefore, even during the operation of the overload protection function, the fluctuation of the room temperature is suppressed and the stability of the room temperature is achieved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In the figure, the same parts as those in FIG. 3 are designated by the same reference numerals, and duplicate description will be omitted.

In FIG. 1, the air conditioner includes an outside air detecting section (temperature sensor) 6 for detecting an outside air temperature (To),
When the detected outside air temperature (To) is in the range shown in Table 2 below, the first to third operation frequency tables (shown in Table 3 below) forming the operation frequency table 7a instead of the operation frequency table 2a shown in FIG. ) Any one of,
The outdoor unit control unit 7 that controls the inverter of the compressor 5 using the selected table is provided. The outdoor unit controller 7 has the function of the outdoor unit controller 2 shown in FIG.

[0016]

[Table 2]

[0017]

[Table 3]

Next, the operation of the air conditioner configured as described above will be described in detail with reference to the graph of FIG. First, assuming that the air conditioner is operated for heating, the temperature detected by the indoor temperature detection unit 3 in the indoor unit control unit 1 (room temperature;
The temperature difference between Tr) and the temperature set by the remote controller setting unit 4 (Ts) is calculated, and an operating frequency code corresponding to the calculated temperature difference is transmitted.

At this time, in the outdoor unit controller 7, the temperature detected by the outside air temperature detector 6 (outside air temperature; To) is shown in Table 1.
It is determined whether or not it is within the range shown in. As is apparent from Table 2, when the outside air temperature (To) is 20 ° C. or higher, control for selecting the third operating frequency table is performed.

The operating frequency code from the indoor unit controller 1 is converted into an operating frequency value using the selected third operating frequency table (shown in Table 3), and the compressor is based on the converted operating frequency. Inverter control of 5.

When the outside air temperature (To) is extremely high, that is, when the protective function (for example, current release) or the overload function is easily operated, conventionally, the current release lowers the operating frequency of the compressor 5. Or the pressure on the high-pressure side due to the refrigeration cycle gradually rises, which raises the temperature of the indoor heat exchanger, and the indoor unit controller 1
In, the overload protection function operates, and the operation and cancellation of the overload function are repeated (shown by the broken line curve in FIG. 2).

However, the third operation frequency table 7a
As is apparent from Table 3, the operating frequency table of No. 2 is smaller in operating frequency value to be converted, as the operating frequency code is larger, as compared with other tables (first and second operating frequency tables). (The interval between operating frequency values is the smallest).

As a result, even if the outside air temperature is extremely high,
Since the operating frequency of the compressor 5 is suppressed to a low level, the operating current does not increase so much, that is, the current release (protection function) is hard to operate, and therefore the frequency of the compressor 5 does not drop and the room temperature deteriorates. Nothing.

Further, when the outside air temperature is extremely high and is in an overload state, for example, as shown by the solid line in FIG. 2, the pressure on the high pressure side in the refrigeration cycle gradually increases, which causes the temperature of the indoor heat exchanger ( Tn) rises and indoor unit control unit 1
When the value exceeds the operating value of the overload function of, the overload function operates. That is, the operating frequency code transmitted from the indoor unit control unit 1 is reduced, but the interval of the operating frequency values in the third operating frequency table is small, so the rate of decrease in the operating frequency of the compressor 5 is small, and The decrease in room temperature is small and the deterioration in room temperature is suppressed. In addition, since the operating frequency of the compressor 5 is suppressed to a low level, the pressure on the high-pressure side due to the refrigeration cycle does not increase so much, that is, the temperature of the indoor heat exchanger is less likely to exceed the operating value of the overload function. Therefore, the room temperature does not deteriorate.

On the other hand, when the temperature (To) detected by the outside air temperature detection unit 6 is higher than 10 ° C. and lower than 20 ° C., the second table of the operating frequency table 7a is referred to by referring to Table 2 as described above.
The operating frequency table of is selected and the detected temperature (T
When o) is 10 ° C. or lower, the second operating frequency table of the operating frequency table 7a is selected with reference to Table 2 as well. The operation frequency code transmitted from the indoor unit controller 1 is converted into an operation frequency value using the first or second operation frequency table selected in this way.

As is apparent from Table 3, the second operating frequency table has a larger operating frequency value to be converted, the operating frequency value interval is larger, and the first operating frequency table is larger than the third operating frequency table. The table is the same as the operating frequency table 2a shown in FIG. 3, and the operating frequency value to be converted is larger and the operating frequency value is larger than the second operating frequency table. That is, when the outside air temperature (To) is not extremely high, the operating frequency value of the compressor 5 is so small that the interval between the operating frequency values need not be so small, and the outside air temperature (To) is normally low. This is because it is not necessary to further reduce the operating frequency value of the compressor 5 and further reduce the interval between the operating frequency values.

As described above, the operating frequency table 7 for converting the operating frequency code from the indoor unit control section 1 into the operating frequency value of the compressor 5 has the first to third operating frequency values and the intervals between the operating frequency values are different. The operating frequency table is configured such that the operating frequency value is smaller and the interval between the operating frequency values is smaller as the outside air temperature (To) is higher.

Therefore, when the operating frequency code from the indoor unit controller 1 is converted into the operating frequency value of the compressor 5, the higher the outside air temperature (To) and the more the overload state, the lower the converted operating frequency value becomes. Since the interval between the converted frequency values becomes small, the protection function (current release) becomes difficult to operate, and the overload protection function in the indoor unit control unit 1 becomes difficult to operate.

As a result, the deterioration of the room temperature can be suppressed, and the drop rate of the operating frequency value of the compressor 5 can be suppressed to be small even during the operation of the overload function. The release is not performed frequently, that is, the fluctuation of the room temperature can be suppressed to be small, and the stability of the room temperature can be improved.

[0030]

As described above, according to the present invention, the operating frequency code of the compressor constituting the refrigeration cycle is calculated based on the room temperature and the set temperature, and the operating frequency corresponding to this operating frequency code is calculated. In an air conditioner in which a compressor is inverter-controlled by the frequency values of the table, the operating frequency table is composed of operating frequency values and first to third operating frequency tables having different intervals of the operating frequency values, and the outside air temperature is low. The operating frequency value is smaller, and the operating frequency table with a smaller interval between the operating frequency values is selected, and the operating frequency code from the indoor unit controller is converted to the operating frequency value of the compressor using the selected operating frequency table. Since the protection function (current release) becomes difficult to operate even if the outside air temperature is extremely low, It is possible to suppress the deterioration of the engine, and even when the overload function is operating, the rate of decrease of the operating frequency value of the compressor is suppressed to a small level, and the overload function is frequently operated and released. Since it does not exist, it is possible to suppress fluctuations in room temperature, which in turn can suppress deterioration in room temperature and improve comfort.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an air conditioner showing an embodiment of the present invention.

FIG. 2 is a schematic graph for explaining the operation of the air conditioner shown in FIG.

FIG. 3 is a schematic block diagram of a conventional air conditioner.

FIG. 4 is a schematic diagram illustrating an operation of a protective function of the air conditioner shown in FIG.

5 is a schematic graph for explaining the operation of the air conditioner shown in FIG.

[Explanation of symbols]

1 Indoor unit control unit 1a Calculation unit 2, 7 Outdoor unit control unit 3 Indoor temperature detection unit 4 Remote control setting unit 5 Compressor 6 Outside air temperature detection unit 7a Operating frequency table (first to third operating frequency tables)

Claims (1)

[Claims] 1. An operating frequency code of a compressor that constitutes a refrigeration cycle is calculated based on at least the indoor temperature and a set temperature, and the compressor is inverter-controlled by a frequency value of an operating frequency table corresponding to this operating frequency code. In the air conditioner, a plurality of operating frequency tables for converting the operating frequency code into the operating frequency value of the compressor are provided, and the operating frequency tables of the plurality have different operating frequency values to be converted. One of the plurality of operating frequency tables is selected based on the temperature detected by the detecting means, and the calculated operating frequency code is converted to the operating frequency value of the compressor by referring to the selected operating frequency table. An air conditioner characterized in that the compressor is controlled based on the converted operating frequency.