JP2007232321A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner which prevents the damage of a compressor by always ensuring the supply of lubricating oil to a compressor sliding part. <P>SOLUTION: The air conditioner has the compressor controlled by the difference between an indoor temperature and a set temperature. When the operation frequency of the compressor is the preset protective operation frequency fpro or less for a predetermined time and the protective operation frequency fpro or more after the lapse of the predetermined time and its difference is a predetermined value f1 or more, the protective operation of the compressor is performed at the protective operation frequency fpro for the predetermined time tpro to cope with the fluctuation of various operation frequencies as well as the starting time of the compressor. Consequently, the supply of lubricating oil to the compressor sliding part is always secured to prevent the damage of the compressor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air conditioner that controls an operating frequency of a compressor based on a difference between a room temperature and a set temperature.

  Conventionally, in this type of air conditioner, when the compressor is stopped, a so-called stagnation phenomenon in which the refrigerant melts and accumulates in the lubricating oil in the hermetic container has frequently occurred. During operation, a large amount of the lubricating oil in the compressor is taken out to the outside by the discharged refrigerant, and the reliability is greatly reduced. A large amount is taken out to the outside by the discharged refrigerant (for example, see Patent Document 1).

  FIG. 5 shows an operating characteristic diagram of a control device in a conventional air conditioner described in Patent Document 1, wherein the horizontal axis represents the time from startup and the vertical axis represents the rotational speed of the refrigerant compressor. .

As shown in FIG. 5, since the first holding frequency f01 at which the compressor is started is set to a low frequency, the amount of the lubricating oil taken out is small and the lubricating oil is secured. However, since the speed is low, the amount of lubricating oil supplied to the sliding portion is small, and therefore operating for a long time reduces the reliability. Therefore, after holding for a relatively short predetermined time, the second holding frequency f02 is provided and the warm-up operation is started. After the operation at the second holding frequency f02, the operation is performed at the rotation speed corresponding to the load. Since the operation is performed at the second holding frequency, the startability can be greatly improved while ensuring the reliability of the refrigerant compressor.
JP-A-7-301460

  However, in the conventional configuration, the control is only performed when the compressor is started, and does not correspond to the sudden change in the compressor frequency thereafter, the long pipe is installed and the compressor frequency is low for a long time, In other words, when the compressor frequency rises from a state where the amount of lubricating oil supplied to the sliding part is low (the lubricating oil level in the compressor is low), a large amount of lubricating oil in the compressor is discharged to the outside of the compressor by the discharged refrigerant. There was a problem that problems such as abnormal wear and seizure occurred due to the lack of lubricating oil in the compressor because the oil was discharged and the lubricating oil was not secured.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide an air conditioner that can prevent damage to the compressor by always ensuring supply of lubricating oil to the compressor sliding portion.

  In order to solve the above-described conventional problem, the air conditioner of the present invention has a compressor operating frequency determined by the difference between the room temperature and the set temperature at a preset operating time fpro below a preset operating frequency fpro. If the difference is equal to or greater than the predetermined value f1 after the lapse of a predetermined time and the protective operation frequency fpro is exceeded, the compressor is protected for the predetermined time tpro and the protective operation frequency fpro.

As a result, not only when the compressor is started, but also when long pipes are installed and the compressor frequency is low for a long time, that is, when the amount of lubricating oil supplied to the sliding part is low (the lubricating oil level in the compressor is low) Since it is possible to cope with fluctuations in various operating frequencies such as when the compressor frequency suddenly increases, supply of lubricating oil to the compressor sliding portion can always be ensured and damage to the compressor can be prevented.

  The air conditioner of the present invention can prevent damage to the compressor by ensuring the supply of lubricating oil to the compressor sliding portion at all times. Can be provided.

  1st invention is an air conditioner which has an indoor heat exchanger, an indoor fan, a compressor, an outdoor heat exchanger, and an outdoor fan, Comprising: The compression which controls the operating frequency of a compressor by the difference of indoor temperature and preset temperature A compressor operating frequency control means, and the compressor operating frequency output by the compressor operating frequency control means is equal to or lower than a preset protective operating frequency fpro for a predetermined time and after a predetermined time has elapsed, the protective operating frequency fpro If the difference is equal to or larger than the predetermined value f1 as described above, the compressor is protected at a predetermined time tpro and the protection operation frequency fpro, so that the compressor is installed not only at the time of starting the compressor, but also installed for a long time and used for a long time. Various operations such as when the frequency of the compressor is increased from a low frequency, that is, when the amount of lubricating oil supplied to the sliding part is low (the lubricating oil level in the compressor is low) Damage can always be ensured supply of lubricant to the compressor sliding parts compressor because it corresponds to the variation of the wave can be prevented.

  The second aspect of the invention protects the operating frequency of the compressor of the first aspect of the invention when the indoor piping temperature falls below a preset value for preventing freezing during the cooling operation and the protective operation of the compressor. By setting the predetermined operating frequency ffrz lower than the operating frequency fpro, it is possible to prevent freezing of the indoor heat exchanger and reduce the discharge amount of lubricating oil in the compressor, thereby improving the reliability of the compressor.

  In the third aspect of the invention, in particular, when the operating frequency of the compressor of the first aspect of the invention exceeds the preset value for the heating overload that the indoor piping temperature is set in advance during the heating operation and the protective operation of the compressor, By setting a predetermined operation frequency fhovl lower than the protection operation frequency fpro, the compressor discharge pressure during heating operation is reduced to protect the compressor, and the discharge amount of lubricating oil in the compressor is reduced to improve the reliability of the compressor. Improvements can be made.

  In the fourth aspect of the invention, in particular, when the operating frequency of the compressor of the first aspect of the invention exceeds the preset value for the cooling overload in which the outdoor pipe temperature is set in advance during the cooling operation and the protective operation of the compressor, By setting a predetermined operation frequency fcovl lower than the protective operation frequency fpro, the discharge pressure of the compressor during cooling operation is reduced to protect the compressor, and the discharge amount of lubricating oil in the compressor is reduced, thereby improving the reliability of the compressor. Improvements can be made.

  In particular, the fifth aspect of the present invention provides a protection operation frequency when the operation frequency of the compressor of the first invention exceeds the preset value for compressor protection during the compressor protection operation. By setting the operation frequency fcmp to be lower than fpro, the compressor winding is prevented from being overheated due to overheat of the compressor, such as insulation deterioration of the motor winding and deterioration of the components, and the discharge amount of the lubricating oil in the compressor is reduced. The reliability can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a refrigeration cycle diagram of an air conditioner according to the first embodiment of the present invention, and FIG. 2 is a block diagram of the air conditioner according to the first embodiment of the present invention.

  In FIG. 1, a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an expansion valve 4, and an outdoor heat exchanger 5 are sequentially connected to form a heat pump type refrigeration cycle.

  An indoor fan 6 that ventilates the indoor heat exchanger 3 and an outdoor fan 7 that ventilates the outdoor heat exchanger 5 are also provided.

  Each of the indoor unit and the outdoor unit includes an indoor temperature sensor 12 for detecting the indoor temperature, an indoor pipe temperature sensor 13 for detecting the pipe temperature of the indoor heat exchanger 3, and an outdoor pipe temperature sensor 22 for detecting the pipe temperature of the outdoor heat exchanger 5. A compressor temperature sensor 23 for detecting the temperature of the compressor 1 is provided, and a signal is sent to the control unit 8 together with a control signal input means 14 provided with an operation stop means for the air conditioner and a temperature adjustment setting means for setting the room temperature. You are typing.

  The control signal input means 14 may be connected to the main body via a communication line, or may be a wireless type such as a remote controller.

  The control unit 8 controls the rotational speeds of the indoor fan 6, the outdoor fan 7, and the compressor 1 through the indoor fan drive control circuit 9, the outdoor fan drive control circuit 10, and the inverter circuit 11.

  In FIG. 2, the control unit 8 comprises a microcomputer, its peripheral circuits, and its program software, and includes an indoor temperature detection means 15, a set temperature reading means 16, an indoor temperature control means 17, a compressor operating frequency control means 18, an indoor piping temperature. A detection means 19, an outdoor pipe temperature detection means 20, a compressor temperature detection means 21 and the like are provided.

  In the present embodiment, the indoor temperature sensor 12 as the indoor temperature detection means 15, the indoor pipe temperature sensor 13 as the indoor pipe temperature detection means 19, the outdoor pipe temperature sensor 22 as the outdoor pipe temperature detection means 20, and the compressor temperature detection means 21 as A compressor temperature sensor 23 is used.

  About the air conditioner comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  FIG. 3 shows a control main routine flowchart of the air conditioner according to the first embodiment of the present invention, and FIG. 4 shows a control subroutine flowchart of the air conditioner according to the first embodiment of the present invention.

  In FIG. 3, the main control starts in step S100 and proceeds to step S101. In step S101, the compressor operating frequency control means determines and outputs the initial compressor operating frequency ft0, and the compressor operating frequency f is set to ft0.

  Next, steps S102 to S107 represent a processing flow for controlling the operating frequency of the compressor based on the difference between the room temperature and the set temperature.

  In step S101, the operation frequency ft0 is set, and after a predetermined time, the process proceeds to step S102, the room temperature Tin is sampled by the room temperature detecting means, and the process proceeds to step S103.

  In steps S103 and S105, it is determined whether the operation mode of the air conditioner is a cooling operation or a heating operation. If it is cooling operation in step S103, it will progress to step S104, and if it is not cooling operation, it will progress to step S105. If it is heating operation in step S105, it will progress to step S106, and if it is not heating operation, it will return to S101.

In step S104, the sampled indoor temperature Tin is compared with the set temperature Ta of the remote controller read by the set temperature reading means, and the difference | Tin−Ta | is larger than the specified value Tch, that is, the actual temperature and the set temperature. If the difference is large, the compressor operating frequency control means determines and outputs the compressor operating frequency ft1 so as to change the compressor operating frequency to a larger one.

  On the other hand, if the difference | Tin−Ta | is smaller than the specified value Tch, that is, if the difference between the actual temperature and the set temperature is small, compression is performed by the compressor operating frequency control means so as to change the operating frequency of the compressor. The machine operating frequency ft1 is determined and output.

  In step S105, the sampled room temperature Tin is compared with the set temperature Ta of the remote controller read by the set temperature reading means, and the difference | Tin−Ta | is larger than the prescribed value Thh, that is, the actual temperature and the set temperature. If the difference is large, the compressor operating frequency control means determines and outputs the compressor operating frequency ft1 so as to change the compressor operating frequency to a larger one.

  On the other hand, if the difference | Tin−Ta | is smaller than the prescribed value Thh, that is, if the difference between the actual temperature and the set temperature is small, compression is performed by the compressor operating frequency control means so as to change the operating frequency of the compressor to a lower one. The machine operating frequency ft1 is determined and output.

  In step S107, the operating frequency f of the compressor is set to ft1 determined by the compressor operating frequency control means.

  Steps S108 to S112 represent a processing flow for performing the protective operation of the compressor.

  In step S108, the initial operating frequency ft0 of the compressor is equal to or lower than a preset protected operating frequency fpro for a predetermined time, and after the predetermined time has elapsed, the changed operating frequency ft1 of the compressor is equal to or higher than the protected operating frequency fpro. If the difference (ft1-ft0) is greater than or equal to the predetermined value f1, the compressor protection operation loop S109 to S112 is entered. Otherwise, the compressor protection operation is not performed, the process proceeds to step S113, and the operation frequency f of the compressor remains set at ft1.

  In step S109, the elapsed time t in the compressor protection operation loop is counted, and the compressor protection operation is continued in the state of steps S110 and S111 until the elapsed time t reaches the predetermined time tpro.

  In step S110, the operation frequency f of the compressor is set to the protection operation frequency fpro, and the compressor is protected. The next step S111 is a subroutine for temperature protection control, the content of which will be described later with reference to FIG.

  When the elapsed time t reaches the predetermined time tpro, the compressor protection operation loop ends in step S112, and the process proceeds to step S113, the operation frequency f of the compressor is returned to ft1, and the original target operation is performed.

As described above, in the control flow from step S108 to step S112, the compressor is protected. For example, when the protection operation frequency fpro is set to 80 Hz and the predetermined value f1 is set to 80 Hz as the prescribed values in the microcomputer memory in advance, the difference between the operation frequency ft1 of the compressor derived from the difference | Tin−Ta | If ft1-ft0) is 80 Hz or more, the compressor is operated at a frequency f of 80 Hz for a predetermined time (for example, 10 minutes). When the supply of lubricating oil to the compressor sliding portion is secured by this compressor protection operation, the operation frequency f of the compressor is returned to the set compressor frequency ft1 for operation.

  With this control, not only at the time of starting the compressor, but also in response to fluctuations in various operating frequencies, it is possible to always ensure the supply of lubricating oil to the compressor sliding part and prevent damage to the compressor. .

  Next, a subroutine for temperature protection control will be described with reference to FIG.

  FIG. 4 is a flowchart of a subroutine executed in step S111 of FIG. 3, and the compressor protection operation loop is entered in step S109 of FIG. 3 immediately before. Accordingly, the temperature protection is further controlled under the condition that the compressor is operating in step S110 where the compressor operating frequency f becomes the protection operating frequency fpro.

  In FIG. 4, sub-control starts in step S200, and the process proceeds to step S201.

  In steps S201 and S211, it is determined whether the operation mode of the air conditioner is a cooling operation or a heating operation. If it is cooling operation in step S201, it will progress to step S202, and if it is not cooling operation, it will progress to step S211. If it is heating operation in step S211, it will progress to step S212, and if it is not heating operation, it will progress to S232.

  In step S202, the indoor pipe temperature detecting means detects the pipe temperature Tpi of the indoor heat exchanger, and if it is smaller than a preset value Tfrz for preventing freezing, it is determined that there is a need for freeze protection, and the flow proceeds to step S203. Go ahead and switch the compressor to freeze-proof operation.

  That is, in step S203, the compressor is operated by changing the operation frequency f of the compressor from the protection operation frequency fpro to the freeze protection operation frequency ffrz. Here, the freeze protection operation frequency ffrz is a preset value for preventing freezing, which is lower than the protection operation frequency fpro, and prevents freezing of the indoor heat exchanger and discharge of lubricating oil in the compressor. The amount is reduced and the reliability of the compressor is improved.

  In this way, the operation of the compressor is switched from the protection operation to the freeze protection operation, and the process proceeds to step 205 without returning to the original compressor protection operation loop.

  In step S202, the indoor pipe temperature detection means detects the pipe temperature Tpi of the indoor heat exchanger, and if it is not smaller than the preset set value Tfrz for preventing freezing, the process proceeds to step S222.

  In step S222, the outdoor pipe temperature detecting means detects the pipe temperature Tpo of the outdoor heat exchanger, and if it exceeds a preset value Tcovl for the preset cooling overload, it is determined that the cooling overload protection is necessary. Proceeding to step S223, the compressor is switched to the cooling overload protection operation.

  That is, in step S223, the operation frequency f of the compressor is changed from the protection operation frequency fpro to the cooling overload protection operation frequency fcovl, and the compressor is operated. Here, the cooling overload protection operation frequency fcovl is a preset value for the cooling overload, and is a value lower than the protection operation frequency fpro to reduce the discharge pressure of the compressor and protect the compressor. The discharge amount of the lubricating oil in the compressor is reduced to improve the reliability of the compressor.

  In this way, the operation of the compressor is switched from the protection operation to the cooling overload protection operation, and the process proceeds to Step 205 without returning to the original compressor protection operation loop.

  In step S212, the piping temperature Tpi of the indoor heat exchanger is detected by the indoor piping temperature detection means, and if it exceeds a preset value Thovl for the heating overload set in advance, it is determined that the heating overload protection is necessary, Proceeding to step S213, the compressor is switched to the heating overload protection operation.

  That is, in step S213, the compressor operating frequency f is changed from the protection operating frequency fpro to the heating overload protection operating frequency fhovl. Here, the heating overload protection operation frequency fhovl is a preset setting value for the heating overload, and is lower than the protection operation frequency fpro to reduce the discharge pressure of the compressor and protect the compressor. The discharge amount of the lubricating oil in the compressor is reduced to improve the reliability of the compressor.

  In this way, the operation of the compressor is switched from the protection operation to the cooling overload protection operation, and the process proceeds to Step 205 without returning to the original compressor protection operation loop.

  In step S232, the compressor temperature detection means detects the compressor temperature Tc, and if it exceeds a preset value Tcmp for the compressor overheat protection, it is determined that the compressor overheat protection is necessary, and step S233 is executed. To switch to compressor overheat protection operation.

  That is, in step S233, the compressor operation frequency f is changed from the protection operation frequency fpro to the compressor overheat protection operation frequency fcmp, and the compressor is operated. Here, the compressor overheat protection operation frequency fcmp is a preset value for the compressor overheat protection, which is lower than the protection operation frequency fpro, and the insulation deterioration of the motor winding due to overheating of the compressor. It is intended to prevent compressor overheating such as deterioration of parts and reduce the discharge amount of lubricating oil in the compressor and improve the reliability of the compressor.

  In this way, the operation of the compressor is switched from the protection operation to the compressor overheat protection operation, and the process proceeds to Step 205 without returning to the original compressor protection operation loop.

  In step S232, the compressor temperature detection means detects the compressor temperature Tc. If the preset temperature Tcmp for the compressor overheat protection is not exceeded, the process proceeds to step 204 and the temperature protection control subroutine is terminated. Then, returning to the compressor protection operation loop starting from step S109 in FIG. 3, the compressor operation frequency fpro is set to the protection operation frequency fpro until the elapsed time t reaches the predetermined time tpro, and the compressor is protected.

  As described above, in the present embodiment, the operation frequency of the compressor is equal to or lower than the preset protection operation frequency fpro for a predetermined time, and after the predetermined time has elapsed, the difference is equal to or greater than the protection operation frequency fpro. If it is above, by carrying out the protection operation of the compressor at the predetermined time tpro and the protection operation frequency fpro, not only at the time of starting the compressor but also long pipe installation and the compressor frequency is low for a long time, that is, sliding Because it can respond to various operating frequency fluctuations, such as when the compressor frequency rises suddenly from a state where the amount of lubricating oil supplied to the part is low (the lubricating oil level in the compressor is low), The supply of lubricating oil can be ensured and damage to the compressor can be prevented.

  Further, in the present embodiment, when the indoor piping temperature falls below a preset value for preventing freezing during the protective operation of the compressor in the cooling operation, the operation frequency of the compressor is set to a predetermined value lower than the protective operation frequency fpro. By setting the operating frequency to ffrz, the indoor heat exchanger can be prevented from freezing and the discharge amount of the lubricating oil in the compressor can be reduced to improve the reliability of the compressor.

Further, in the present embodiment, when the indoor piping temperature exceeds a preset heating overload set value during the compressor protection operation in the heating operation, the compressor operation frequency is lower than the protection operation frequency fpro. By setting the predetermined operating frequency fhovl, it is possible to reduce the discharge pressure of the compressor during the heating operation and protect the compressor, and to reduce the discharge amount of the lubricating oil in the compressor, thereby improving the reliability of the compressor. .

Further, in the present embodiment, when the outdoor piping temperature exceeds a preset value for the cooling overload during the compressor protection operation in the cooling operation, the operation frequency of the compressor is lower than the protection operation frequency fpro. By setting the predetermined operating frequency fcovl, it is possible to reduce the discharge pressure of the compressor during the cooling operation and protect the compressor, and to reduce the discharge amount of the lubricating oil in the compressor, thereby improving the reliability of the compressor. .
In the present embodiment, when the compressor temperature exceeds a preset value for compressor protection during the compressor protection operation, the compressor operation frequency is lower than the protection operation frequency fpro. By setting the frequency to fcmp, the compressor winding is prevented from being overheated due to overheating of the compressor and the components are deteriorated, and the discharge amount of lubricating oil in the compressor is reduced, thereby improving the reliability of the compressor. be able to.

  As described above, the air conditioner according to the present invention can prevent the compressor from being damaged by always ensuring the supply of the lubricating oil to the compressor sliding portion, and is highly reliable for the user. Therefore, it can be applied to uses such as a dehumidifier having a compressor.

Refrigeration cycle diagram of the air conditioner in Embodiment 1 of the present invention The block diagram of the air conditioner in Embodiment 1 of this invention Control main routine flowchart of the air conditioner according to Embodiment 1 of the present invention. Control subroutine flowchart of the air conditioner according to Embodiment 1 of the present invention. Operation characteristic diagram of control device in conventional air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Indoor heat exchanger 4 Expansion valve 5 Outdoor heat exchanger 6 Indoor fan 7 Outdoor fan 8 Control part 9 Indoor fan drive control circuit 10 Outdoor fan drive control circuit 11 Inverter circuit 12 Indoor temperature sensor 13 Indoor piping Temperature sensor 14 Control signal input means 15 Indoor temperature detection means 16 Set temperature reading means 17 Indoor temperature control means 18 Compressor operating frequency control means 19 Indoor pipe temperature detection means 20 Outdoor pipe temperature detection means 21 Compressor temperature detection means 22 Outdoor Piping temperature sensor 23 Compressor temperature sensor

Claims (5)

An air conditioner having an indoor heat exchanger, an indoor fan, a compressor, an outdoor heat exchanger, and an outdoor fan, the compressor operating frequency control means for controlling the operating frequency of the compressor based on the difference between the indoor temperature and the set temperature The compressor operating frequency output by the compressor operating frequency control means is less than or equal to a preset protected operating frequency fpro for a predetermined time, and after a predetermined time has passed, the difference is greater than or equal to the protected operating frequency fpro. If it is more than predetermined value f1, the air conditioner characterized by performing the protection operation | movement of a compressor by predetermined time tpro and the said protection operation frequency fpro. The indoor piping temperature detecting means for detecting the piping temperature of the indoor heat exchanger is provided, and the indoor piping temperature detected by the indoor piping temperature detecting means during the cooling operation and the protective operation of the compressor is set to prevent freezing. 2. The air conditioner according to claim 1, wherein when the value falls below a set value for the compressor, the operation frequency of the compressor is set to a predetermined operation frequency ffrz lower than the protection operation frequency fpro. An indoor pipe temperature detecting means for detecting the pipe temperature of the indoor heat exchanger is provided, and the indoor pipe temperature detected by the indoor pipe temperature detecting means during the heating operation and the protective operation of the compressor is set to a preset overheating temperature. The air conditioner according to claim 1, wherein when the set value for the load is exceeded, the operation frequency of the compressor is set to a predetermined operation frequency fhovl lower than the protection operation frequency fpro. An outdoor pipe temperature detecting means for detecting the pipe temperature of the outdoor heat exchanger is provided, and the outdoor pipe temperature detected by the outdoor pipe temperature detecting means during the cooling operation and the compressor protecting operation is a preset cooling over temperature. The air conditioner according to claim 1, wherein if the set value for the load is exceeded, the operation frequency of the compressor is set to a predetermined operation frequency fcovl lower than the protection operation frequency fpro. A compressor temperature detecting means for detecting the temperature of the compressor is provided, and the compressor temperature detected by the compressor temperature detecting means during the protective operation of the compressor is a preset setting for protecting the compressor. 2. The air conditioner according to claim 1, wherein when the value is exceeded, the operation frequency of the compressor is set to a predetermined operation frequency fcmp lower than the protection operation frequency fpro.

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