JPH10318615A - Operation control device of air-conditioning equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively prevent a liquid refrigerant from staying in a compressor case by performing a positive correction to a frequency command at each specific time when the detection temperature of a refrigerant and a lubricant in the compressor is lower than a specific value when the operation frequency of the compressor is controlled according to a frequency command in response to an air-conditioning load. SOLUTION: The capacity of a compressor 2 is adjusted while the compressor 2 is driven at a variable speed by a compressor motor 9 consisting of an AC motor, and the AC motor 40 is driven under a frequency corresponding to the compressor rotation speed in response to the requested air-conditioning capacity at each time via a frequency converter 44 from an AC system power supply 42. In this case, a pseudo overheating control is performed and at the same time the output frequency of the frequency converter 44 is controlled according to a temperature deviation of ΔTA in an outdoor machine controller 48. However, at a region where an outdoor discharge pipe temperature TD is lower than a specific value, it is regarded that a frequency command Cf is too low and a positive correction is made where each specific frequency, for example, 2.5 Hz is added at each specific time for the frequency command Cf.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for an air conditioner, and more particularly, to a refrigeration cycle having a variable capacity compressor, an outdoor heat exchanger, a throttle mechanism, and an indoor heat exchanger. An indoor unit controller that issues a frequency command according to the required air conditioning load, such as a deviation between the indoor temperature and the set indoor temperature, and an operating frequency of the compressor that receives a frequency command from the indoor unit controller and responds to the frequency command And an outdoor unit controller for controlling the operation of the air conditioner.

[0002]

2. Description of the Related Art In an air conditioner equipped with a variable capacity compressor, the rotational speed, that is, the operating frequency of the compressor is changed according to the air conditioning load corresponding to the difference between the temperature of the room to be air-conditioned and the set temperature. Control and adjust the air conditioning capacity. In such an air conditioner, depending on the indoor and outdoor temperature,
Under temperature conditions where the degree of dilution of lubricating oil in the compressor is likely to rise, to prevent it: 1. Always set a higher frequency according to the command from the indoor unit controller. Measures are taken to prevent operation at frequencies below the frequency at which the degree of dilution increases.

[0003] From the same viewpoint, There are also measures to bypass the high-temperature gas inside the compressor so that the compressor does not become cold.

[0004]

However, the above measures 1, 2, and 3 have the following inconveniences. In other words, under the measures 1 and 2, the compressor is eventually operated under a load condition that is always higher than the air conditioning load, which goes against the concept of energy saving and requires it. The opportunity to operate with excessive capacity for the air conditioning load increases, and the opportunity to operate the compressor intermittently in a short cycle increases. As a result, not only does the durability of the compressor deteriorate, but also the comfort of air conditioning often deteriorates. Further, the variable width of the operating frequency becomes narrow, and the variable width of the capacity of the air conditioner with respect to the air conditioning load becomes small, and the usable temperature range of the air conditioner cannot be expanded.

[0005] In the measures (3), the operating efficiency at the time of low-frequency operation is deteriorated, and the compressor is easily overheated at the time of overload operation, which causes a decrease in the reliability of the compressor.

Accordingly, the present invention is to control the operation of an air conditioner that can prevent the liquid refrigerant from stagnation in the compressor case during low-capacity, low-frequency operation and improve the reliability of the compressor during low-load operation. It is intended to provide a device.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention provides a refrigeration cycle having a variable capacity compressor, an outdoor heat exchanger, a throttle mechanism, and an indoor heat exchanger. An indoor unit controller that issues a frequency command according to an air conditioning load to be performed, and an operation control device for an air conditioner including an outdoor unit controller that controls an operating frequency of a compressor according to a frequency command from the indoor unit controller, A temperature detecting means for detecting a temperature state of the refrigerant and the lubricating oil in the compressor, and when a temperature detected by the temperature detecting means is lower than a predetermined value, a frequency command input from the indoor unit controller to the outdoor unit controller is applied for a predetermined time And a correction control means for performing a predetermined amount of positive correction every time.

According to a second aspect of the present invention, in the operation control device for an air conditioner according to the first aspect, the temperature detecting means detects a temperature of a discharge side pipe of the compressor.

According to a third aspect of the present invention, the temperature detecting means is a compressor case temperature detecting means for detecting a case temperature of the compressor.

According to a fourth aspect of the present invention, in the operation control device for an air conditioner according to the first aspect, the temperature detecting means is a compressor lubricating oil temperature detecting means for detecting a lubricating oil temperature of the compressor. It is characterized by the following.

According to a fifth aspect of the present invention, in the operation control device for an air conditioner according to the first aspect, the temperature detecting means includes a discharge pipe temperature, a compressor case temperature, and a compressor lubricating oil temperature. And at least two temperature detecting means for detecting at least two temperatures of the at least two temperature detecting means, the correction control means, when at least one detected temperature of at least two or more temperature detecting means is lower than a predetermined value, from the indoor unit controller to the outdoor unit controller It is characterized in that a predetermined amount of positive correction is added to the input frequency command every predetermined time.

According to a sixth aspect of the present invention, in the operation control device for an air conditioner according to the first aspect, the temperature detecting means includes a discharge pipe temperature, a compressor case temperature, and a lubricating oil dilution degree of the compressor. First detecting means for detecting at least one of the following, and second detecting means for detecting the temperature of the refrigerant liquid returned to the compressor as the degree of superheating of the refrigerant in the refrigeration cycle or the temperature associated therewith, A positive correction to a frequency command from the indoor controller based on the detection result of the detection means is executed on condition that the temperature detected by the second detection means is higher than a predetermined value.

According to a seventh aspect of the present invention, in the operation control device for an air conditioner according to any one of the first to sixth aspects, the correction control means includes a controller for controlling the compressor to operate at a frequency higher than a frequency command from the indoor unit controller. When the frequency command from the indoor unit controller becomes higher than the operating frequency of the compressor during operation, the frequency command output from the outdoor unit controller is immediately changed to the frequency value corresponding to the frequency command from the indoor unit controller. It is characterized by being raised.

According to an eighth aspect of the present invention, in the operation control device for an air conditioner according to any one of the first to fifth aspects, the correction control means includes a current detection means for detecting a current of a motor for driving the compressor. When the current detection value by the current detection means exceeds a predetermined value while the compressor is operating at a frequency higher than the frequency command from the indoor unit controller, the stage output from the outdoor unit controller indicates the discharge pipe temperature. At least two temperature detecting means for detecting at least two of the compressor case temperature and the compressor lubricating oil temperature, and the correction control means detects at least one of the at least two or more temperature detecting means. When the temperature is lower than a predetermined value, a predetermined amount of positive correction is applied to the frequency command from the indoor unit controller via the outdoor unit controller at predetermined time intervals. It is an feature.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

<Refrigeration Cycle and Sensor Arrangement> FIG. 3 shows a refrigeration cycle to which the present invention is applied and arrangement positions of various sensors according to the present invention.

This refrigeration cycle includes a compressor 2, a four-way valve 4, an outdoor heat exchanger 6, an electronic control valve 8, an indoor heat exchanger 1,
0 and the accumulator 12. The indoor heat exchanger 10 is included in the indoor unit, and the other devices are included in the outdoor unit. Although only one indoor heat exchanger 10 is illustrated, two or more indoor heat exchangers may be provided in parallel as needed. Here, the description will be made on the assumption that the cooling operation is performed. In the case of the cooling operation, the four-way valve 4 is switched as shown by a solid line arrow, and the refrigerant discharged from the compressor 2 passes through the four-way valve 4 and further the outdoor heat exchanger 6, the electronic control valve 8, the indoor heat exchanger 10, four-way valve 4
Then, the flow returns to the compressor 2 via the accumulator 12. In this case, the outdoor heat exchanger 6 functions as a condenser, and the indoor heat exchanger 10 functions as an evaporator. By the way, during the heating operation, the four-way valve 4 is switched as shown by the dashed arrow, and the refrigerant discharged from the compressor 2 passes through the four-way valve 4 and further passes through the indoor heat exchanger 10, the electronic control valve 8, and the outdoor heat exchange. Bowl 6,
It returns to the compressor 2 via the four-way valve 4 and the accumulator 12. In this case, the outdoor heat exchanger 6 functions as an evaporator, and the indoor heat exchanger 10 functions as a condenser. This refrigeration cycle additionally has a connection point between the outdoor heat exchanger 6 and the electronic control valve 8 and the four-way valve 4 and the accumulator 12.
And a connection point for the saturation temperature detection capillary 14.

The indoor heat exchanger 10 includes an indoor suction air temperature sensor 20 for detecting the indoor suction air temperature TA and an indoor heat exchanger temperature sensor 2 for detecting the indoor heat exchanger temperature TC.
2 are provided. The compressor 2 has its case temperature T
A compressor case temperature sensor 24 for detecting K and a lubricating oil dilution sensor 26 for detecting a lubricating oil dilution OQ are provided, and an outdoor discharge for detecting an outdoor discharge pipe temperature TD is provided on a discharge side pipe of the compressor 2. A tube temperature sensor 28 is provided.
An outdoor suction pipe temperature sensor 30 for detecting an outdoor suction pipe temperature TS is provided between the four-way valve 4 and the accumulator 12. The outdoor heat exchanger 6 is provided with an outdoor heat exchanger temperature sensor 32 for detecting the temperature TE, and a low-pressure saturation temperature sensor for detecting a low-pressure saturation temperature TU in a pipe connecting between the accumulator 12 and the capillary 14. 36 are provided.

<Embodiment 1> FIG.
1 shows an embodiment corresponding to the present invention. The compressor (CP) 2 is a compressor motor (CM) composed of an AC motor
The capacity is adjusted by being driven at a variable speed by 40. Therefore, the AC motor 40 is
Is driven through the frequency converter 44 at a frequency corresponding to the compressor rotational speed according to the required air conditioning capacity in each case. Here, the compressor rotation speed, that is, the motor rotation speed, is represented by the input frequency of the motor 40, that is, the output frequency of the frequency converter 44, which substantially corresponds thereto.

The indoor unit including the indoor heat exchanger 10 is provided with an indoor unit controller 46. The indoor intake air temperature TA detected by the temperature sensor 20 is taken in as indicating the room temperature, and the room temperature set value TM and The frequency command Cf corresponding to the output frequency (= input frequency of the compressor motor 40) of the frequency converter 44 necessary to make the difference, that is, the room temperature deviation ΔTA (= TM−TA) zero, is compared with the outdoor unit. It is sent to the controller 48. The outdoor unit controller 48 includes an outdoor discharge pipe temperature sensor 28.
The outdoor discharge pipe temperature TD detected by the outdoor suction pipe temperature TS detected by the outdoor suction pipe temperature sensor 30,
And the low-pressure saturation temperature TU detected by the low-pressure saturation temperature sensor 36 is introduced.

Here, it is assumed that pseudo superheat control is performed using the outdoor suction pipe temperature TS and the low pressure saturation temperature TU. The outdoor unit controller 48 basically receives the frequency command Cf from the indoor unit controller 46 and sends a frequency command Sf to the frequency converter 44 based on the frequency command Cf to control the output frequency. The frequency converter 44 outputs a voltage having a frequency corresponding to the frequency command Sf, thereby adjusting the number of revolutions of the compressor motor 40, that is, the number of revolutions of the compressor 2, and controlling its ability.

The outdoor unit controller 48 basically controls the output frequency of the frequency converter 44 in accordance with the temperature deviation ΔTA while performing pseudo superheat degree control. The outdoor discharge pipe temperature TD detected by the temperature sensor 28 is monitored, and the frequency command Cf is corrected according to the monitored value. Therefore, the outdoor unit controller 48 includes the correction control means according to the present invention. Now, as exemplified in FIG. 2, the outdoor discharge pipe temperature T
Hysteresis is given to the set value of D, and when the temperature TD is in the process of falling, the hold zone upper limit value Db = 47 ° C.
Hold zone lower limit value Dd = 44 ° C., hold zone lower limit value Dc = 45 ° C., hold zone upper limit value (= slow down zone lower limit value) Db = 47 in the ascending process.
° C and the slowdown zone upper limit Da = 52 ° C. As can be seen from the figure, Da> Db
>Dc> Dd.

When the outdoor discharge pipe temperature TD is in the hold zone (Db ≧ TD ≧ Dd when the temperature TD is in the process of decreasing, and Db ≧ TD ≧ Dc when the temperature TD is in the process of increasing), correction is performed. Regardless of whether the frequency command has been corrected or not, no correction is made to the frequency command Cf at that time. However, the outdoor discharge pipe temperature TD is lower than the slow-up zone (the zone below the hold zone, and TD <Dd during the descending process and TD <during the rising process).
If the operation is continued for a long time in Dc), the refrigerant may be liquefied inside the case of the compressor 2 and fall into the lubricating oil. In such a state, the lubricating oil is diluted, causing poor lubrication and the like, thereby impairing the reliability of the compressor. Therefore, according to the present invention, a region where the outdoor discharge pipe temperature TD is lower than the predetermined value is set as a slow-up zone, and the outdoor unit controller 48 determines that the frequency command Cf is too low.
For f, a positive correction of slow-up is performed such that a predetermined frequency, for example, 2.5 Hz is added every predetermined time, for example, every two minutes. On the other hand, the "instruction-based zone" is Db <TD when the outdoor discharge pipe temperature TD is in the process of decreasing, and Da <TD when the temperature TD is in the process of increasing. It is considered that there is no possibility that the refrigerant liquefies inside the case of the compressor 2 and stagnates in the lubricating oil, and the outdoor unit controller 48 outputs the frequency command Cf as it is as the frequency command Sf. When the outdoor discharge pipe temperature TD value is in the process of rising, the range of Db <TD ≦ Da is a slowdown zone, and the outdoor unit controller 48 adjusts the frequency command Cf to 5 Hz every minute in order to correct the excessive rise. Frequency command S with slow down correction, that is, negative correction
f is sent to the frequency converter 44.

By controlling as described above, the refrigerant inside the compressor 2 is efficiently expelled to the outside by the heat generation effect inside the compressor 2 to prevent the refrigerant from liquefying inside the compressor case and falling asleep. As a result, a situation such as poor lubrication due to dilution of the lubricating oil can be prevented, and the reliability of the compressor can be improved.

<Embodiment 2> FIG. 4 shows an embodiment corresponding to the third aspect of the present invention. In this embodiment, a compressor case temperature TK having a correlation with the outdoor discharge pipe temperature TD detected by the outdoor discharge pipe temperature sensor 28 in the first embodiment is used. The compressor case temperature TK is detected by a compressor case temperature sensor 24. However, the compressor case temperature T
Considering that K is in a considerably lower temperature state than the outdoor discharge pipe temperature TD, unlike the case where the zoning section value regarding the detected value of the compressor case temperature TK is the temperature TD,
Modify as follows. That is, specific examples of the set values Ka to Kd of the compressor case temperature TK in FIG. 5 corresponding to the set values Da to Dd of the outdoor discharge pipe temperature TD in FIG. 2 are as follows. That is, Ka = 25 ° C., Kb
= 20 ° C, Kc = 10 ° C, and Kd = 5 ° C.

The control mode of the apparatus shown in FIGS. 4 and 5 is basically similar to the control mode of the apparatus shown in FIGS. 1 and 2, and the set values Da, Db, Dc and Dd are replaced with the former set values Da, Db, Dc and Dd. The only difference is that the set values Ka, Kb, Kc, and Kd are used. Here, when the compressor case temperature TK is in the slow-up zone (TK <Kd during the descending process, TK <Kc during the ascending process), the frequency command Sf becomes low for the same reason as in the first embodiment. If it is considered too long, a correction is made such that it is added every predetermined time, for example, every two minutes, every predetermined frequency, for example, 2.5 Hz. When the TK value is in the slow down zone,
That is, in the ascending process, when Kb <TK ≦ Ka, a negative correction is made to the frequency command Sf by 5 Hz every minute to correct the frequency command Sf from rising too much.

The feature of the second embodiment is that the frequency command Sf is corrected using the compressor case temperature TK as described above. Although the compressor case temperature TK is slightly delayed from the lubricating oil temperature in the compressor 2 due to the heat capacity of the case, a value close to the actual lubricating oil temperature can be detected. Can be controlled. According to the second embodiment, the same operation and effect as those of the first embodiment can be obtained.

<Embodiment 3> FIG. 6 shows an embodiment corresponding to the fourth aspect of the present invention. In this embodiment, the outdoor discharge pipe temperature T in Embodiment 1 is set.
D, or compressor case temperature TK in the second embodiment
, The dilution degree OQ of the lubricating oil inside the compressor 2 is used. The compressor lubrication oil dilution degree OQ is detected by a compressor lubrication oil dilution degree sensor 26. Here, since the compressor lubricating oil dilution degree OQ has a correlation with the lubricating oil temperature, it can be used for correcting the frequency command Cf. In consideration of such a correlation, as shown in FIG. 7, the category of the compressor lubricating oil dilution degree OQ is set as follows. That is, for example, the set values Qa to Qd for the compressor lubricating oil dilution degree OQ in FIG. 7 corresponding to the section set values Ka to Kd of the compressor case temperature TK in FIG. 5 are set as follows, for example. That is, Qa = 10%, Qb = 1
5%, Qc = 20%, and Qd = 25%.

The control mode of the apparatus shown in FIGS. 6 and 7 is basically similar to the control mode of the first and second embodiments described with reference to FIGS. 6 to 7 instead of the section setting values Da to Dd of the outdoor discharge pipe temperature TD in the apparatus of FIG. 2 or the section setting values Ka to Kd of the compressor case temperature TK in the apparatus of FIGS. The only difference is that the set values Qa to Qd of the compressor lubricating oil dilution degree OQ are used. Here, the compressor lubricating oil dilution degree OQ is set in the slow-up zone (OQ <Q during the descending process).
d, when OQ <Qc during the rising process, for the same reason as in the first and second embodiments, the frequency command Cf is set at a predetermined frequency, for example, 2.times. A positive correction such as adding 5 Hz is added. When the OQ value is in the slow down zone, that is, when the OQ value is in the process of rising and is in the range of Qb <OQ ≦ Qa, the frequency is increased by 5 Hz every minute to suppress the frequency command Cf. A negative correction is applied to the command Cf.

As described above, it is possible to modify the frequency command Cf using the compressor lubricating oil dilution OQ in the third embodiment.
It is a feature of. 4 and 5 using compressor case temperature TK
If the heat capacity of the compressor case is too large,
Delay in response to cycle changes can be a problem. In such a case, according to the devices of FIGS. 6 and 7, the compressor lubricating oil dilution OQ is directly detected, so that the responsiveness can be improved.

<Embodiment 4> FIG. 8 shows an embodiment corresponding to the fifth aspect of the present invention. This embodiment corresponds to a combination of the first embodiment and the second embodiment. That is, here, both the outdoor discharge pipe temperature TD and the compressor case temperature TK are used for correcting the frequency command Cf described above. Then, the detected temperature T
When at least one of D and TK is equal to or less than a predetermined value (TD <Dd or (and) TK <Kd during the descending process, TD <Dc or (and) TK <Kc during the ascending process),
As described above, in response to the frequency command Cf, a predetermined frequency, for example, 2..
A positive correction such as adding 5 Hz is added. Similarly, when at least one of the TD value and the TK value is in the slowdown zone (Db <TD ≦ Da or (and) Kb <TK ≦ Ka in the ascending process), the frequency command Cf is lowered. In order to correct it, a negative correction is applied to the frequency command Cf for 5 Hz every minute. In this embodiment, the detected temperatures TD, TK
May be a condition that one of them is in the above-mentioned zone, or may be a condition that both of them are in the above-mentioned zone.

As described above, by using the outdoor discharge pipe temperature TD and the compressor case temperature TK, the internal refrigerant is driven out due to the heat generation effect inside the compressor 2, and the refrigerant liquefies inside the case and falls asleep. Prevent the situation,
As a result, it is possible to prevent the occurrence of poor lubrication due to dilution of the lubricating oil, and to further ensure the above-described effect of improving the reliability of the compressor.
It should be noted that the method of correcting the frequency command Cf on condition that both the temperatures TD and TK are in the slow-up zone increases the reliability of the compressor as compared with the case where either one is in that zone. While further improving and achieving the intended purpose, the compressor can be operated at a frequency as low as possible, and a further energy saving effect can be achieved.

<Embodiment 5> FIG. 9 shows an embodiment corresponding to the sixth aspect of the present invention. This embodiment is a system in which frequency control based on the degree of superheat is used in combination with the first embodiment, and can be implemented by diverting the device configuration of FIG. In the apparatus shown in FIG. 1, the section setting values of the outdoor discharge pipe temperature TD shown in FIG. 2 are used. Further, the outdoor suction pipe temperature T detected by the outdoor suction pipe temperature sensor 30 is used.
Using S and the low-pressure saturation temperature TU detected by the low-pressure saturation temperature sensor 36, the value of TH = TS-TU is set as the superheat degree TH, and this is used as a frequency command slow-up control based on the temperature classification of the outdoor discharge pipe temperature TD. Alternatively, one condition of the slowdown control is set. Regarding the degree of superheat TH, as shown in FIG. 9, for example, a boundary value of 3 ° C. is set as an Hz (frequency) up control permission zone above, and a Hz up control inhibition zone below it.

By adopting the control method based on the superheat degree classification shown in FIG. 9, even if the outdoor discharge pipe temperature TD is in the slow-up zone, the superheat degree TH is in the Hz-up control permission zone (TH ≧ 3). , The slow-up control for the frequency command Cf is permitted. When the superheat degree TH is not in the Hz-up control permission zone (TH> 3), that is, when TH <3, even if the outdoor discharge pipe temperature TD is in the slow-up zone, the slow-up correction for the frequency command Cf is not performed. not allowed.

In the case of the system shown in FIGS. 1 and 2, when a temporary liquid back cycle occurs, the frequency is reduced before the throttling by the superheat control.
The frequency may be increased, and the Hz may be increased other than when the low frequency operation is laid down. On the other hand, in the above-described fifth embodiment, it is possible to perform the Hz-up correction only when the outdoor discharge pipe temperature TD decreases even though the superheat degree TH is appropriate. Hz contrary to the spirit of energy saving
Up driving can be prevented.

In this embodiment, as the basic control mode, the compressor case temperature TK,
And the compressor lubricating oil dilution OQ can be used. Still further, instead of the degree of superheat of the refrigerant, the temperature of the refrigerant liquid returned to the compressor may be used as the temperature related thereto.

<Sixth Embodiment> A sixth embodiment is a modification of the first embodiment. Embodiment 6 is shown in FIGS.
When the compressor 2 is operated at a frequency higher than the operating frequency based on the frequency command Cf from the indoor unit controller 46 in the device of FIG. 2, the outdoor discharge pipe temperature TD is in the hold zone or the slow-up zone in FIG. However, when the operating frequency based on the frequency command Cf becomes higher than the actual operating frequency, the operation shifts to the “instruction-based zone” ignoring the Hz hold or the Hz slow-up, and immediately the indoor unit controller 46. Is increased to a frequency command corresponding to the capability request command Cf. As described above, according to this embodiment, it is possible to promptly correspond to the frequency command Cf in response to an increase in the frequency command Cf from the indoor unit controller 46.

In this embodiment, a compressor case temperature TK or a compressor lubricating oil dilution degree OQ can be used instead of the outdoor discharge pipe temperature TD.

<Embodiment 7> In this embodiment, as shown in FIG. 10, a current detector 50 for detecting a motor current Im is provided in an input current circuit of a compressor motor 40, and its current detection value Is added to the above-described correction control. Here, as an example, the current detector 50 is connected to the frequency converter 44.
Is provided on the input side, but it may be provided on the output side of the frequency converter 44. The correction of the frequency command by the zone division of the outdoor discharge pipe temperature TD, the compressor case temperature TK, and the compressor lubrication oil dilution degree OQ in FIGS. This is to add protection control based on the detected value. In the current increasing direction, as shown in FIG.
21A is set as a threshold, Im ≦ 21A is set as a Hz up zone, and an operation frequency rise is corrected by 1 Hz every 5 seconds. A range of Im> 21A is set as a Hz down zone and operated at 2.5 Hz every 1 second. It is assumed that frequency drop is corrected. Further, in the current value decreasing direction, two threshold values Im = 21A and Im = 20A are set, and
m> 21A as a Hz down zone, 2.5 per second
The frequency of operation is corrected in steps of Hz, and 21A ≧ Im>
It is assumed that the operating frequency in each case is held by setting the range of 20A as a hold zone, and that the operation frequency is increased by 1 Hz every 5 seconds by setting Im ≦ 20A as a Hz up zone.

The seventh embodiment is based on the control by the apparatus shown in FIGS. 1 and 2, and attempts to take the motor current Im into consideration. The outdoor unit controller 48 controls the indoor unit 48 according to the detected value of the temperature TD. Command correction control based on the outdoor discharge pipe temperature TD when the current value Im exceeds the threshold value 21A and enters the Hz down zone in the case where the frequency command Cf from the machine controller 46 has already been positively corrected. The current value dependent control is prioritized, and the frequency command Cf is corrected by lowering by 2.5 Hz every second. If Im ≦ 20 A during the current decreasing process, the operating frequency is increased by 1 Hz every 5 seconds as an Hz up zone.

This embodiment is effective as a protection means in the case where the outdoor discharge pipe temperature sensor 28 is separated from the outdoor discharge pipe and cannot detect the outdoor discharge pipe temperature TD. When the current Im exceeds a predetermined value and is likely to be in a failure state, by performing the frequency down control, such an inconvenient situation can be avoided.

In this embodiment, a compressor case temperature TK or a compressor lubricating oil dilution degree OQ can be used instead of the outdoor discharge pipe temperature TD.

[0042]

The advantage of the variable capacity type air conditioner is that it operates at a low frequency to reduce the capacity when the indoor air conditioning load is small.

However, if the cooling operation is performed under low temperature conditions both indoors and outdoors, the compressor is operated at a low frequency, and therefore, depending on the state of the refrigeration cycle, the refrigerant liquefies inside the compressor case and falls down. The lubricant of the compressor may be diluted. According to the present invention, by increasing the frequency in such a case, it is possible to prevent such an increase in the degree of dilution of the lubricating oil by the refrigerant, and to prevent a failure due to poor lubrication of the compressor or liquid compression. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an operation control device for an air conditioner according to the present invention, which corresponds to claims 1 and 2;

FIG. 2 is a diagram illustrating a region division relating to a detected value of an outdoor discharge pipe temperature in FIG. 1;

FIG. 3 is a diagram showing a refrigeration cycle to which the present invention is applied and arrangement positions of various sensors according to the present invention.

FIG. 4 is a block diagram showing an embodiment of an air conditioner operation control device according to the present invention, corresponding to claim 3;

FIG. 5 is a diagram illustrating a region division relating to a detected value of a compressor case temperature in FIG. 4;

FIG. 6 is a block diagram showing an embodiment of an operation control device for an air conditioner according to the present invention, which corresponds to claim 4;

FIG. 7 is a diagram for explaining a region division relating to a detected value of a lubricating oil dilution degree in FIG. 6;

FIG. 8 is a block diagram showing an embodiment of an operation control device for an air conditioner according to the present invention, which corresponds to claim 5;

FIG. 9 is a diagram for explaining an embodiment of an operation control device for an air conditioner according to the present invention, which corresponds to claim 6;

FIG. 10 is a block diagram showing an embodiment of an air conditioner operation control device according to the present invention, which corresponds to claim 8;

FIG. 11 is a diagram illustrating a region division related to a detected value of a motor current in FIG. 10;

[Explanation of symbols]

 2 Compressor 4 Four-way valve 6 Outdoor heat exchanger 8 Throttle mechanism 10 Indoor heat exchanger 12 Accumulator 14 Capillary 46 Indoor unit controller 48 Outdoor unit controller 20 Indoor suction air temperature sensor 22 Indoor heat exchanger temperature sensor 24 Compressor case temperature sensor 26 Lubricating oil dilution degree sensor 28 Outdoor discharge pipe temperature sensor 30 Outdoor suction pipe temperature sensor 32 Outdoor heat exchanger temperature sensor 36 Low pressure saturation temperature sensor 40 Compressor motor (CM) 42 AC system power supply 44 Frequency converter 46 Indoor 48 Outdoor unit Controller 50 Current detector

Claims (8)

[Claims] 1. A refrigeration cycle having a variable capacity compressor, an outdoor heat exchanger, a throttle mechanism, and an indoor heat exchanger, an indoor unit controller for issuing a frequency command corresponding to a required air conditioning load, and the indoor unit An air conditioner operation control device including an outdoor unit controller that receives a frequency command from a controller and controls an operation frequency of the compressor according to the frequency command, wherein a temperature state of refrigerant and lubricating oil in the compressor is provided. The temperature command detected by the temperature detecting means is lower than a predetermined value. When a frequency command input from the indoor unit controller to the outdoor unit controller is corrected by a predetermined amount every predetermined time, An operation control device for an air conditioner, comprising: a correction control unit for adding a correction value. 2. The operation control device for an air conditioner according to claim 1, wherein said temperature detecting means detects a temperature of a discharge side pipe of said compressor. Control device. 3. An operation control device for an air conditioner, wherein the temperature detecting means is a compressor case temperature detecting means for detecting a case temperature of the compressor. 4. An operation control device for an air conditioner according to claim 1, wherein said temperature detecting means is a compressor lubricating oil temperature detecting means for detecting a lubricating oil temperature of said compressor. Air conditioner operation control device. 5. The operation control device for an air conditioner according to claim 1, wherein said temperature detecting means comprises: a temperature of said discharge pipe;
At least two temperature detecting means for detecting at least two temperatures of a case temperature of the compressor and a temperature of lubricating oil of the compressor, wherein the correction control means is provided with at least two or more temperature detecting means; An operation of the air conditioner, wherein a predetermined amount of positive correction is added to the frequency command input from the indoor unit controller to the outdoor unit controller every predetermined time when at least one detected temperature is lower than a predetermined value. Control device. 6. An operation control device for an air conditioner according to claim 1, wherein said temperature detecting means comprises: a temperature of said discharge pipe;
First detecting means for detecting at least one of a case temperature of the compressor and a lubricating oil dilution degree of the compressor; and a refrigerant superheat degree of the refrigeration cycle or a temperature related to the refrigerant superheat degree to the compressor. A second detection unit for detecting a temperature of the return refrigerant liquid, wherein a positive correction to a frequency command from the indoor controller based on a detection result of the first detection unit is detected by the second detection unit. An operation control device for an air conditioner, which is executed on condition that the temperature is higher than a predetermined value. 7. The operation control device for an air conditioner according to claim 1, wherein the correction control means comprises:
When the frequency command from the indoor unit controller becomes higher than the operating frequency of the compressor while the compressor is operating at a frequency higher than the frequency command from the indoor unit controller, the output from the outdoor unit controller is output. An operation control device for an air conditioner, wherein the frequency command is immediately increased to a frequency value corresponding to the frequency command from the indoor unit controller. 8. The operation control device for an air conditioner according to claim 1, wherein the correction control means includes:
Current detection means for detecting the current of the motor driving the compressor, wherein the current detection value by the current detection means in a state where the compressor is operated at a frequency higher than the frequency command from the indoor unit controller An operation control device for an air conditioner, wherein a frequency command output from the outdoor unit controller is decreased by a predetermined amount at predetermined time intervals when a predetermined value is exceeded.