CN111279138A

CN111279138A - Air conditioner

Info

Publication number: CN111279138A
Application number: CN201880069422.0A
Authority: CN
Inventors: 伊藤裕; 仲田贵裕; 冈诚司; 芦泽智春
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2017-10-30
Filing date: 2018-09-27
Publication date: 2020-06-12
Anticipated expiration: 2038-09-27
Also published as: EP3705808B1; JP6601472B2; WO2019087630A1; EP3705808A1; EP3705808A4; JP2019082279A; CN111279138B

Abstract

The air conditioner includes: a compressor capable of changing an operating frequency; and a control unit that executes compressor protection control for increasing the operating frequency of the compressor to a required operating frequency at the start of the cooling operation or the heating operation. The compressor protection control has a1 st protection control and a2 nd protection control. The 1 st protection control controls the operating frequency of the compressor so that the time from the start of the compressor until the operating frequency reaches the necessary operating frequency is relatively long. The 2 nd protection control controls the operating frequency of the compressor so that the time from the start of the compressor until the operating frequency reaches the necessary operating frequency is relatively short. The control unit executes the 2 nd protection control when a predetermined condition is satisfied when the compressor protection control is executed.

Description

Air conditioner

Technical Field

The present invention relates to an air conditioner.

Background

Conventionally, in an air conditioner, in order to prevent liquid from returning to a compressor at the start of a cooling operation or a heating operation, a start-up operation is performed in which the operating frequency of the compressor is reduced for a predetermined time after the compressor is started (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 6-341720

Disclosure of Invention

Problems to be solved by the invention

However, at the start of the cooling operation or the heating operation, the liquid does not necessarily return to the compressor. That is, depending on the environment around the compressor at the start of the cooling operation or the heating operation, the liquid may be less likely to return to the compressor. In this case as well, if the start-up operation is performed with the operating frequency of the compressor reduced, the time from when the compressor is started until the indoor temperature reaches the set temperature becomes long, and it is difficult to accelerate the start-up of the cooling operation or the heating operation.

The purpose of the present invention is to provide an air conditioning apparatus that can accelerate the start of cooling operation or heating operation.

Means for solving the problems

An air conditioner that solves the problem includes: a compressor capable of changing an operating frequency; and a control unit that executes compressor protection control for increasing the operating frequency of the compressor to a required operating frequency at the start of the cooling operation or the heating operation. The compressor protection control has a1 st protection control and a2 nd protection control. The 1 st protection control controls the operating frequency of the compressor such that a time from the start of the compressor until the operating frequency reaches the necessary operating frequency is relatively long. The 2 nd protection control controls the operating frequency of the compressor in such a manner that a time from the start of the compressor until the operating frequency reaches the necessary operating frequency is relatively short. The control unit executes the 2 nd protection control when a predetermined condition is satisfied when the compressor protection control is executed.

According to this configuration, when the predetermined condition is satisfied when the compressor protection control is executed, the 2 nd protection control is executed, whereby the time from the start of the compressor until the operating frequency of the compressor reaches the necessary operating frequency is shortened. This can shorten the time from the start of the cooling operation or the heating operation to the time when the indoor temperature reaches the set temperature, and can speed up the start of the cooling operation or the heating operation.

Here, the predetermined condition means the following condition: when the compressor is started, the operating frequency of the compressor is rapidly increased, and as a result, the possibility of a problem that the liquid level in the compressor decreases, the dilution progresses due to the return of the refrigerant, the liquid returns to the compressor, the heat exchanger functioning as an evaporator in the outdoor heat exchanger and the indoor heat exchanger freezes, and the suction side of the compressor becomes a negative pressure or the like is reduced.

Preferably, the control unit sets a1 st target frequency and a2 nd target frequency that is higher than the 1 st target frequency and lower than the required operating frequency in the compressor protection control. The control unit maintains the operating frequency at the 1 st target frequency for the 1 st period and maintains the operating frequency at the 2 nd target frequency for the 2 nd period, thereby increasing the operating frequency of the compressor in stages. The 1 st target frequency in the 2 nd protection control is larger than the 1 st target frequency in the 1 st protection control. The 2 nd target frequency in the 2 nd protection control is larger than the 2 nd target frequency in the 1 st protection control.

According to this configuration, the time from the start of the compressor to the time when the operating frequency of the compressor reaches the required operating frequency is shortened by the 2 nd protection control. Therefore, the start of the cooling operation or the heating operation can be speeded up.

Preferably, the control unit sets a1 st target frequency and a2 nd target frequency that is higher than the 1 st target frequency and lower than the required operating frequency in the compressor protection control. The control unit maintains the operating frequency at the 1 st target frequency for the 1 st period and maintains the operating frequency at the 2 nd target frequency for the 2 nd period, thereby increasing the operating frequency of the compressor in stages. The 1 st period in the 2 nd protection control is shorter than the 1 st period in the 1 st protection control. The 2 nd period in the 2 nd protection control is shorter than the 2 nd period in the 2 nd protection control.

Preferably, the predetermined condition during the heating operation and the predetermined condition during the cooling operation are different.

With this configuration, the 2 nd protection control can be appropriately executed during the cooling operation or the heating operation.

Preferably, the predetermined condition includes a temperature of indoor air, a temperature of outdoor air, and a temperature difference between the temperature of the indoor air and the temperature of the outdoor air.

Preferably, the predetermined condition during the heating operation is: the temperature of the indoor air is below a room temperature threshold, the temperature of the outdoor air is above an outside air temperature threshold, and the temperature difference between the temperature of the indoor air and the temperature of the outdoor air is below a temperature difference threshold.

According to this configuration, it is possible to set conditions that can suppress the occurrence of a failure in the compressor such as the liquid return to the compressor during the compressor protection control, using the temperature of the indoor air and the temperature of the outdoor air that are easily acquired as information of the air conditioner.

Preferably, the predetermined condition includes a temperature of a discharge pipe of the compressor and a temperature of outdoor air.

With this configuration, the 2 nd protection control can be executed more appropriately during the cooling or heating operation.

Drawings

Fig. 1 is a schematic diagram showing an air conditioner according to embodiment 1.

Fig. 2 is a block diagram showing an electrical configuration of the air conditioner.

Fig. 3 is a graph showing transition of the operating frequency of the compressor in the compressor protection control.

Fig. 4 is a graph showing a relationship between the indoor temperature, the outdoor air temperature, and a temperature difference between the indoor temperature and the outdoor air temperature, and a possibility of a failure of the compressor.

Fig. 5 is a diagram for selecting the 1 st protection control and the 2 nd protection control during the heating operation.

Fig. 6 is a diagram for selecting the 1 st protection control and the 2 nd protection control during the cooling operation.

Fig. 7 is a flowchart showing processing steps of the 1 st start-up control performed by the air conditioner.

Fig. 8 is a flowchart showing the processing procedure of the 2 nd activation control in the air conditioning apparatus according to embodiment 2.

Fig. 9 is a diagram showing a relationship between the temperature of the discharge pipe of the compressor and the outside air temperature in the air conditioning apparatus according to the modification.

Detailed Description

(embodiment 1)

The air conditioner 1 will be described below with reference to the drawings.

As shown in fig. 1, the air conditioner 1 includes a refrigerant circuit 40. The refrigerant circuit 40 includes a refrigerant pipe 30 for circulating a refrigerant between the outdoor unit 10 and the indoor unit 20. The air conditioning apparatus 1 of the present embodiment includes a refrigerant circuit 40 formed by connecting an outdoor unit 10 installed outdoors and a wall-mounted indoor unit 20 attached to an indoor wall surface or the like by a refrigerant pipe 30.

The outdoor unit 10 includes a compressor 11 capable of changing an operating frequency, a four-way switching valve 12, an outdoor heat exchanger 13, an expansion valve 14, an outdoor fan 15, an outdoor control device 16, and the like. The outdoor fan 15 includes a motor 15a as a drive source capable of changing a rotation speed, and an impeller 15b connected to an output shaft of the motor 15 a. An example of the impeller 15b is a propeller fan.

The compressor 11 is, for example, a swing piston type compressor, and includes a compression mechanism, a motor, a crankshaft (not shown) for transmitting a driving force of the motor to the compression mechanism, and the like. The compressor 11 has a gas-liquid separator 11a for separating the refrigerant into gas and liquid. An example of the motor is a 3-phase brushless motor. The expansion valve 14 is, for example, an electronic expansion valve. The outdoor fan 15 rotates the impeller 15b by the motor 15a to promote heat exchange between the refrigerant flowing through the heat transfer tubes of the outdoor heat exchanger 13 and the outdoor air. Thereby, the outdoor blower 15 generates an airflow of outdoor air passing through the outdoor heat exchanger 13. The outdoor control device 16 is electrically connected to the motor of the compressor 11, the four-way switching valve 12, the expansion valve 14, and the motor 15a of the outdoor blower 15.

The indoor unit 20 includes an indoor heat exchanger 21, an indoor fan 22, an indoor controller 23, and the like. The indoor fan 22 includes a motor 22a as a drive source capable of changing a rotation speed, and an impeller (not shown) connected to an output shaft of the motor 22 a. An example of the impeller is a cross flow fan. The indoor blower 22 rotates an impeller by a motor 22a to promote heat exchange between the refrigerant flowing through the heat transfer tubes of the indoor heat exchanger 21 and the indoor air. Thereby, the indoor fan 22 generates an airflow of the indoor air passing through the indoor heat exchanger 21. The indoor control device 23 is electrically connected to the motor 22a of the indoor blower 22. The indoor control device 23 is configured to be capable of performing wireless communication with a remote controller 51 (see fig. 2) of the air conditioner 1 by infrared rays or the like, for example. The indoor control device 23 is configured to be capable of wired communication with the outdoor control device 16 through a signal line. Thus, the indoor control device 23 controls the indoor unit 20 and the outdoor control device 16 controls the outdoor unit 10 in response to the operation instruction from the remote controller 51.

The refrigerant circuit 40 is formed by annularly connecting the compressor 11, the four-way switching valve 12, the outdoor heat exchanger 13, the expansion valve 14, and the indoor heat exchanger 21 by the refrigerant pipes 30. The refrigerant circuit 40 can execute a vapor compression refrigeration cycle in which a refrigerant is reversibly circulated by switching the four-way switching valve 12.

That is, by switching the four-way switching valve 12 to the cooling mode connection state (the state shown by the solid line), the refrigerant circuit 40 forms a refrigeration cycle in which the refrigerant circulates in the order of the compressor 11, the four-way switching valve 12, the outdoor heat exchanger 13, the expansion valve 14, the indoor heat exchanger 21, the four-way switching valve 12, and the compressor 11. Thus, in the air conditioning apparatus 1, the cooling operation is performed in which the outdoor heat exchanger 13 functions as a condenser and the indoor heat exchanger 21 functions as an evaporator. Further, by switching the four-way switching valve 12 to the heating mode connection state (the state shown by the broken line), a heating cycle in which the refrigerant circulates in the order of the compressor 11, the four-way switching valve 12, the indoor heat exchanger 21, the expansion valve 14, the outdoor heat exchanger 13, the four-way switching valve 12, and the compressor 11 is formed in the refrigerant circuit 40. As a result, in the air conditioning apparatus 1, a heating operation is performed in which the indoor heat exchanger 21 functions as a condenser and the outdoor heat exchanger 13 functions as an evaporator.

As shown in fig. 2, the control unit 50 for controlling the air-conditioning apparatus 1 includes the outdoor control device 16 and the indoor control device 23. The outdoor control device 16 and the indoor control device 23 each include, for example, an arithmetic processing device and a storage unit that execute a predetermined control program. The arithmetic Processing device includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The storage unit stores various control programs and information used for various control processes. The storage unit includes, for example, a nonvolatile memory and a volatile memory.

The remote controller 51, the indoor temperature sensor 52, the outdoor temperature sensor 53, and the discharge pipe temperature sensor 54 are communicably connected to the control unit 50.

More specifically, the control unit 50 is configured to be capable of wireless communication with a remote controller 51 (see fig. 3) by infrared rays or the like, for example. In other words, signals of an operation instruction (an instruction for cooling operation, heating operation, or the like) or an operation stop instruction from the remote controller 51 are output to the control unit 50. The indoor temperature sensor 52, the outdoor temperature sensor 53, and the discharge pipe temperature sensor 54 are electrically connected to the control unit 50. The indoor temperature sensor 52 is a sensor for measuring the temperature of the indoor air (indoor temperature), and is provided, for example, near the inlet of the indoor unit 20. The indoor temperature sensor 52 outputs a signal corresponding to the indoor temperature to the control unit 50. The outdoor temperature sensor 53 is a sensor for measuring the temperature of outdoor air (outdoor temperature), and is provided, for example, near the suction port of the outdoor unit 10. The outdoor temperature sensor 53 outputs a signal corresponding to the outdoor temperature to the control unit 50. The discharge pipe temperature sensor 54 is a sensor for measuring the temperature of the discharge pipe of the compressor 11, that is, the temperature of the discharge gas refrigerant discharged from the compressor 11. A discharge pipe temperature sensor 54 is attached to the discharge pipe of the compressor 11. The discharge pipe temperature sensor 54 outputs a signal corresponding to the temperature of the discharge gas refrigerant of the compressor 11 to the control unit 50. In this way, various signals (operation instruction or measurement information) are input to the control unit 50 from the remote controller 51, the indoor temperature sensor 52, the outdoor temperature sensor 53, and the discharge pipe temperature sensor 54. Then, the control unit 50 acquires an indoor temperature (hereinafter, referred to as "indoor temperature DA") from the measurement information of the indoor temperature sensor 52, an outdoor temperature (hereinafter, referred to as "outdoor temperature DOA") from the measurement information of the outdoor temperature sensor 53, and a temperature DF (temperature of the discharge gas refrigerant) of the discharge pipe of the compressor 11 from the measurement information of the discharge pipe temperature sensor 54.

Further, since the indoor control device 23 and the outdoor control device 16 are electrically connected, the indoor control device 23 can output the received operation instruction and the indoor temperature DA to the outdoor control device 16. The outdoor control device 16 can output the received outside air temperature DOA and the temperature DF of the discharge pipe of the compressor 11 to the indoor control device 23.

The indoor control device 23 controls the rotation speed of the motor 22a of the indoor blower 22 based on the operation instruction or measurement information of the remote controller 51.

The outdoor control device 16 controls the operating frequency of the compressor 11, the switching between the cooling mode connection state and the heating mode connection state of the four-way switching valve 12, the opening degree of the expansion valve 14, and the rotation speed of the motor 15a of the outdoor fan 15, based on the operation instruction or measurement information of the remote controller 51.

The control unit 50 executes the cooling operation and the heating operation based on the operation instruction and the measurement information of the remote controller 51 via the indoor control device 23 and the outdoor control device 16. The control unit 50 controls the compressor 11, the expansion valve 14, the outdoor fan 15, and the indoor fan 22 so that the indoor temperature is set by the remote controller 51 during the cooling operation and the heating operation.

The control unit 50 sets the same raising speed and the same lowering speed so that the raising speed when raising the operating frequency of the compressor 11 and the lowering speed when lowering the operating frequency are equal to each other in the cooling operation and the heating operation. An example of the speed of changing the operating frequency of the compressor 11 in the cooling operation and the heating operation, such as the rising speed and the falling speed, is 2Hz per second.

Further, the control unit 50 increases the low operating frequency of the compressor 11 so as to reach the operating frequency required for the cooling operation or the heating operation (hereinafter, referred to as "required operating frequency FN") at the time of starting the compressor 11 at the time of starting the operation of the cooling operation or the heating operation. In this case, the control unit 50 executes the compressor protection control at the start of the compressor 11. In the compressor protection control, in order to avoid a problem with the compressor 11, the operating frequency of the compressor 11 is started at a low operating frequency and is increased in stages with the elapse of time until the required operating frequency FN required for stable operation of the compressor 11 is reached. Further, as the defects of the compressor 11, there are cases where the operating frequency of the compressor 11 is rapidly increased at the start-up of the compressor 11, and the liquid level in the compressor 11 is lowered or the dilution degree is advanced by the return of the refrigerant, and the liquid is returned to the compressor 11, and the freezing of the heat exchanger functioning as the evaporator among the outdoor heat exchanger 13 and the indoor heat exchanger 21 is generated, and the suction side of the compressor 11 becomes a negative pressure.

The graph GX shown by the broken line in fig. 3 is a schematic graph for explaining a general compressor protection control.

As shown in the graph GX of fig. 3, the compressor protection control is changed as follows: the target frequencies of the plurality of stages are maintained for the entire predetermined time until the operating frequency of the compressor 11 reaches the required operating frequency FN. In detail, the controller 50 stores the 1 st target frequency FX1, the 2 nd target frequency FX2 higher than the 1 st target frequency FX1, the 3 rd target frequency FX3 higher than the 2 nd target frequency FX2, and the 4 th target frequency FX4 higher than the 3 rd target frequency FX3 in the compressor protection control. The controller 50 drives the compressor 11 so that the operating frequency of the compressor 11 becomes the 1 st target frequency FX1 at time t1, and drives the compressor 11 so that the operating frequency of the compressor 11 maintains the 1 st target frequency FX1 during a period from time t1 to time t 3. At time t3, controller 50 drives compressor 11 such that the operating frequency of compressor 11 changes from 1 st target frequency FX1 to 2 nd target frequency FX2, and drives compressor 11 such that the operating frequency of compressor 11 maintains 2 nd target frequency FX2 between time t3 and time t 5. At time t5, controller 50 drives compressor 11 such that the operating frequency of compressor 11 changes from 2 nd target frequency FX2 to 3 rd target frequency FX3, and drives compressor 11 such that the operating frequency of compressor 11 maintains 3 rd target frequency FX3 between time t5 and time t 6. At time t6, controller 50 drives compressor 11 such that the operating frequency of compressor 11 changes from 3 rd target frequency FX3 to 4 th target frequency FX4, and drives compressor 11 such that the operating frequency of compressor 11 maintains 4 th target frequency FX4 between time t6 and time t 7. At time t7, controller 50 drives the compressor 11 such that the operating frequency of compressor 11 is set from target frequency 4 FX4 to required operating frequency FN.

In addition, in the graph GX of fig. 3, the difference between the 2 nd target frequency FX2 and the 1 st target frequency FX1 (FX2-FX1), the difference between the 3 rd target frequency FX3 and the 2 nd target frequency FX2 (FX3-FX2), and the difference between the 4 th target frequency FX4 and the 3 rd target frequency FX3 (FX4-FX3) are equal to each other. In addition, the operation frequency of the compressor 11 is equal to each other during the 1 st period TX1 for maintaining the 1 st target frequency FX1, during the 2 nd period TX2 for maintaining the 2 nd target frequency FX2, during the 3 rd period TX3 for maintaining the 3 rd target frequency FX3, and during the 4 th period TX4 for maintaining the 4 th target frequency FX 4.

However, when the compressor protection control is executed at the start of the operation of the cooling operation or the heating operation, the trouble of the compressor 11 can be avoided, and on the other hand, the operating frequency of the compressor 11 is gradually increased as shown in the graph GX in fig. 3, so that the time from when the user instructs the cooling operation or the heating operation by using the remote controller 51 until the temperature of the indoor air becomes the set temperature becomes long. That is, the start-up of the cooling operation or the heating operation at the start of the operation of the cooling operation or the heating operation is difficult, and as a result, the cooling capacity or the heating capacity at the start of the operation of the cooling operation or the heating operation is decreased.

On the other hand, depending on the ambient environment of the compressor 11 (the temperature of outdoor air or the temperature of indoor air), there is a low possibility that a failure of the compressor 11 may occur. When the compressor protection control shown in the graph GX in fig. 3 is executed even when there is a low possibility that a failure of the compressor 11 occurs, the operation of the compressor 11 in which the cooling capacity or the heating capacity is reduced is executed although the failure of the compressor 11 is not likely to occur.

In view of this, in the present embodiment, the control unit 50 executes the 1 st start-up control for changing the control format of the compressor protection control depending on whether the possibility of the occurrence of the malfunction of the compressor 11 is high or low. Specifically, when there is a high possibility that a failure occurs in the compressor 11, the control unit 50 executes the 1 st protection control, which is the compressor protection control shown in the graph GX of fig. 3. On the other hand, when there is a low possibility that a failure of the compressor 11 occurs, the control unit 50 executes the 2 nd protection control for rapidly increasing the operating frequency of the compressor 11 to the required operating frequency FN as compared with the compressor protection control (the 1 st protection control) shown in the graph GX of fig. 3.

The details of the 2 nd protection control will be described.

The 2 nd protection control has a1 st target frequency FA1 and a2 nd target frequency FA 2. That is, the number of target frequencies of the 2 nd protection control is smaller than the number of target frequencies of the 1 st protection control. The 1 st target frequency FA1 is greater than the 1 st target frequency FX1 of the 1 st protection control. The 1 st target frequency FA1 of the present embodiment is equal to the 2 nd target frequency FX2 of the graph GX. The 2 nd target frequency FA2 is greater than the 2 nd target frequency FX2 of the 1 st protection control. The 2 nd target frequency FA2 of the present embodiment is larger than the 4 th target frequency FX4 of the graph GX and smaller than the required operating frequency FN. The 1 st and 2 nd target frequencies FA1 and FA2 and FA1 are equal to each other in difference (FA2-FA 1). The difference (FA2-FA1) between the 2 nd target frequency FA2 and the 1 st target frequency FA1 is larger than the difference (FN-FA2) between the necessary operating frequency FN and the 2 nd target frequency FA 2. The 1 st period TA1 during which the operating frequency of the compressor 11 maintains the 1 st target frequency FA1 and the 2 nd period TA2 during which the operating frequency of the compressor 11 maintains the 2 nd target frequency FA2 are equal to each other.

In the 2 nd protection control, the controller 50 controls the operating frequency of the compressor 11 to be the 1 st target frequency FA1, and then controls the operating frequency of the compressor 11 to be the 1 st target frequency FA1 for the entire predetermined time. Then, the controller 50 controls the operating frequency of the compressor 11 to be the 2 nd target frequency FA2 from the 1 st target frequency FA1, and controls the operating frequency of the compressor 11 to be the 2 nd target frequency FA2 for the entire predetermined time, and thereafter controls the operating frequency of the compressor 11 to be the required operating frequency FN from the 2 nd target frequency FA 2. In the 2 nd protection control, the 1 st period TA1, which is controlled so that the operating frequency of the compressor 11 is maintained at the 1 st target frequency FA1, is shorter than the 1 st period TX1, which is controlled so that the operating frequency of the compressor 11 is maintained at the 1 st target frequency FX1 in the 1 st protection control. Further, the 2 nd period TA2 that is controlled so that the operating frequency of the compressor 11 maintains the 2 nd target frequency FA2 is shorter than the 2 nd period TX2 that is controlled so that the operating frequency of the compressor 11 maintains the 2 nd target frequency FX2 in the 1 st protection control.

The graph GA of fig. 3 shows transition of the operating frequency of the compressor 11 based on the 2 nd protection control. As shown in the graph GA, the controller 50 drives the compressor 11 at time t1 so that the operating frequency of the compressor 11 becomes the 1 st target frequency FA1, and drives the compressor 11 so that the operating frequency of the compressor 11 maintains the 1 st target frequency FA1 during a period from time t1 to time t2 (period TA 1). Then, at time t2, controller 50 drives compressor 11 such that the operating frequency of compressor 11 becomes 2 nd target frequency FA2 from 1 st target frequency FA1, and drives compressor 11 such that the operating frequency of compressor 11 maintains 2 nd target frequency FA2 during the period from time t2 to time t4 (period TA 2). Then, at time t4, the controller 50 drives the compressor 11 so that the operating frequency of the compressor 11 becomes the required operating frequency FN from the 2 nd target frequency FA 2. In this way, a period TA (period from time t1 to time t 4) from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 2 nd protection control is shorter than a period TX (period from time t1 to time t 8) from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 1 st protection control.

Next, a possibility of occurrence of a failure in the compressor 11 will be described.

The possibility of occurrence of a malfunction of the compressor 11 can be estimated using the temperature of the indoor air (indoor temperature) and the temperature of the outdoor air (outdoor temperature). More specifically, the possibility of occurrence of a failure in the compressor 11 can be estimated from the indoor temperature DA, the outdoor temperature DOA, and the temperature difference between the indoor temperature DA and the outdoor temperature DOA. The present inventors found, through experiments and the like, a temperature condition with a low possibility of occurrence of a failure of the compressor 11 at the start of the heating operation and a temperature condition with a low possibility of occurrence of a failure of the compressor 11 at the start of the cooling operation.

However, when the indoor temperature DA is high at the start of the heating operation, the necessity of quickly increasing the indoor temperature DA, that is, the necessity of increasing the heating capacity is low. When the indoor temperature DA is low at the start of the cooling operation, the necessity of quickly lowering the indoor temperature DA, that is, the necessity of increasing the cooling capacity is low. In this way, when the necessity of improving the heating capacity or the cooling capacity is low, the 1 st protection control is executed as the compressor protection control, whereby the trouble of the compressor 11 can be avoided more reliably.

Fig. 4 is an example of the results of a test conducted by the inventors of the present application as to whether or not a failure has occurred in the compressor 11 when the 2 nd protection control of the compressor protection control is executed at the start of the heating operation when the indoor temperature DA, the outdoor temperature DOA, and the temperature difference between the indoor temperature DA and the outdoor temperature DOA are changed. In fig. 4, the vertical axis shows the indoor temperature DA and the horizontal axis shows the outdoor air temperature DOA. The hatched lines in the temperature map show the difference between the indoor temperature DA and the outdoor temperature DOA (DA-DOA), i.e., the difference between the indoor temperature DA and the outdoor temperature DOA. The dotted portion in the temperature chart of fig. 4 shows an example of a temperature region (hereinafter, referred to as "temperature region RL") in which the possibility of a failure of the compressor 11 occurring at the start of the heating operation is low and the necessity of improving the heating capacity is high. The temperature region RL is a temperature region surrounded by conditions of an indoor temperature DA of 20 ℃ or lower, an outdoor temperature DOA of 0 ℃ or higher, and an inside-outside temperature difference X5 or lower. An example of the difference X5 between the internal and external temperatures is 10 ℃. Specifically, if the outside air temperature DOA is 0 ℃ or higher and the difference between the inside and outside temperatures is 10 ℃ or lower, the possibility of a malfunction occurring in the compressor 11 when the 2 nd protection control of the compressor protection control is executed at the start of the heating operation is low. In other words, when the outside temperature DOA is less than 0 ℃ or the inside-outside temperature difference is greater than 10 ℃, there is a high possibility that a problem occurs in the compressor 11 when the 2 nd protection control of the compressor protection control is executed at the start of the heating operation. On the other hand, when the indoor temperature DA is higher than 20 ℃ and the difference between the internal temperature and the external temperature is 10 ℃ or lower, there is a low possibility that a problem occurs in the compressor 11 when the 2 nd protection control of the compressor protection control is executed at the start of the heating operation.

Although not shown, the present inventors have conducted experiments on whether a failure has occurred in the compressor 11 when the 2 nd protection control of the compressor protection control is executed at the start of the cooling operation when the indoor temperature DA, the outdoor temperature DOA, and the temperature difference between the indoor temperature DA and the outdoor temperature DOA are changed, as in the heating operation. According to such a test, the temperature conditions that are low in the possibility of occurrence of a failure of the compressor 11 at the start of the cooling operation or the heating operation and high in the necessity of improving the cooling or heating capacity are as follows. The temperature conditions during the cooling operation and the heating operation are stored in the controller 50 as, for example, a map MP1 during the heating operation in fig. 5 and a map MP2 during the cooling operation in fig. 6.

[ heating operation ] (a1) the indoor temperature DA is 1 st judgment temperature (room temperature threshold) DAX1 or less (DA. ltoreq. DAX 1). (a2) The outside air temperature DOA is within the temperature range of 1 st (DOAL1 ≦ DOA ≦ DOAH 1). DOAL1 indicates the lower limit value of the 1 st temperature range, and DOAH1 indicates the upper limit value of the 1 st temperature range. (a3) The temperature difference between the indoor temperature DA and the outdoor air temperature DOA is equal to or less than the 1 st judgment temperature difference (temperature difference threshold) DDX1 (DA-DOA is less than or equal to DDX).

Here, the 1 st determination temperature DAX1 is a determination value for determining whether or not the indoor temperature is required to be increased in heating capacity. An example of the 1 st determination temperature DAX1 is 13 ℃. The lower limit value DOAL1 of the 1 st temperature range is an outside air temperature determination value for determining whether or not there is a low possibility that a malfunction of the compressor 11 will occur at the start of the heating operation. An example of the lower limit value of DOAL1 is 0 ℃. The upper limit value DOAH1 of the 1 st temperature range is a determination value for determining whether or not the outside air temperature is required to improve the heating capacity. An example of the upper limit value DOAH1 is 24 ℃. The 1 st determination temperature difference DDX1 is a determination value of the inside-outside temperature difference that determines whether or not there is a low possibility that a failure of the compressor 11 occurs at the start of the heating operation. An example of the 1 st determination temperature difference DDX1 is 10 ℃.

[ cooling operation ] (b1) the indoor temperature DA is equal to or higher than the 2 nd judgment temperature (room temperature threshold) DAX2 (DA. gtoreq.DAX 2). (b2) The outside air temperature DOA is within the range of temperature 2 (DOAL2 ≦ DOA ≦ DOAH 2). DOAL2 indicates the lower limit of the 2 nd temperature range, and DOAH2 indicates the upper limit of the 2 nd temperature range. (b3) The temperature difference between the indoor temperature DA and the outdoor air temperature DOA is equal to or less than the 2 nd judgment temperature difference (temperature difference threshold) DDX2 (DA-DOA is less than or equal to DDX 2).

Here, the 2 nd determination temperature DAX2 is a determination value for determining whether or not the indoor temperature is required to be increased in cooling capacity. An example of the determination temperature DAX2 of the 2 nd determination temperature is 25 ℃. The lower limit value DOAL2 of the 2 nd temperature range is a determination value for determining whether or not the outside air temperature is required to be increased in cooling capacity. An example of a lower limit value of DOAL2 is 25 ℃. The upper limit value DOAH2 of the 2 nd temperature range is an outside air temperature determination value for determining whether or not there is a low possibility that a failure of the compressor 11 occurs at the start of the cooling operation. An example of the upper limit value DOAH2 is 45 ℃. The 2 nd determination temperature difference DDX2 is a determination value of the inside-outside temperature difference that determines whether or not there is a low possibility that a failure of the compressor 11 occurs at the start of the operation of the cooling operation. An example of the determination temperature difference DDX2 in the 2 nd determination is-10 ℃.

The controller 50 uses the map MP1 to select the 1 st protection control and the 2 nd protection control at the start of the heating operation, based on the temperature conditions a1, a2, and a3 of the heating operation. The controller 50 uses the map MP2 to select the 1 st protection control and the 2 nd protection control at the start of the cooling operation, based on the temperature conditions b1, b2, and b3 of the cooling operation.

The vertical axis of the map MP1 shows the indoor temperature DA, and the horizontal axis shows the outdoor air temperature DOA. In addition, the inclined line in the map MP1 shows the boundary condition of the inside-outside temperature difference. In the map MP1, a temperature region R1 satisfying all the temperature conditions a1, a2, a3 is shown with dots. That is, the temperature region R1 is a region in which the 2 nd protection control is selected, and the region other than the temperature region R1 is a region in which the 1 st protection control is selected.

The temperature region R1 of the map MP1 may be the same region as the temperature region RL of fig. 4. That is, the 1 st determination temperature DAX1, the lower limit value DOAL1, the upper limit value DOAH1, and the 1 st determination temperature difference DDX1 in the temperature conditions a1, a2, and a3 of the heating operation may be set to 20 ℃, 0 ℃, 30 ℃, and 10 ℃.

The vertical axis of the map MP2 shows the indoor temperature DA, and the horizontal axis shows the outdoor air temperature DOA. In addition, the inclined line in the map MP2 shows the boundary condition of the inside-outside temperature difference. In the map MP2, a temperature region R2 satisfying all the temperature conditions b1, b2, b3 is shown by dots. That is, the temperature region R2 is a region in which the 2 nd protection control is selected, and the region other than the temperature region R2 is a region in which the 1 st protection control is selected.

In the 1 st start-up control, the control unit 50 selects one of the 1 st protection control and the 2 nd protection control using the map MP1 at the start of the heating operation, and selects one of the 1 st protection control and the 2 nd protection control using the map MP2 at the start of the cooling operation.

The processing procedure of the 1 st start-up control will be described with reference to fig. 7.

The control unit 50 determines whether or not the heating operation is instructed in step S11. The determination of step S11 is made, for example, based on whether or not the control unit 50 has received a command for heating operation from the remote controller 51. If it is determined in step S11 that the heating operation is instructed (yes in step S11), control unit 50 selects map MP1 in step S12. Then, in step S13, the control unit 50 determines whether or not the coordinates defined by the indoor temperature DA and the outdoor temperature DOA are within the range of the temperature range R1 in the map MP 1. When the control unit 50 determines that the coordinates defined by the indoor temperature DA and the outdoor temperature DOA are within the range of the temperature range R1 (yes in step S13), that is, when it determines that all the temperature conditions a1 to a3 are satisfied, the 2 nd protection control is selected in step S14. On the other hand, when the control unit 50 determines that the coordinates defined by the indoor temperature DA and the outdoor temperature DOA are outside the range of the temperature range R1 (no in step S13), that is, when it determines that at least one of the temperature conditions a1 to a3 is not satisfied, the 1 st protection control is selected in step S15.

If it is determined in step S11 that the heating operation has not been instructed (no in step S11), the controller 50 determines in step S16 whether the cooling operation has been instructed. The determination of step S16 is made, for example, based on whether or not the control unit 50 has received a command for the cooling operation from the remote controller 51. If it is determined in step S16 that the cooling operation has been instructed (yes in step S16), controller 50 selects map MP2 in step S17. Then, in step S18, the control unit 50 determines whether or not the coordinates defined by the indoor temperature DA and the outdoor temperature DOA are within the range of the temperature range R2 in the map MP 2. If it is determined that the coordinates defined by the indoor temperature DA and the outdoor temperature DOA are within the range of the temperature range R2 (yes in step S18), that is, if it is determined that all of the temperature conditions b1 to b3 are satisfied, the control unit 50 proceeds to step S14. That is, the control unit 50 selects the 2 nd protection control. On the other hand, when the control unit 50 determines that the coordinates defined by the indoor temperature DA and the outdoor temperature DOA are outside the range of the temperature range R2 (no in step S18), that is, when it determines that at least one of the temperature conditions b1 to b3 is not satisfied, the 1 st protection control is selected in step S19.

If it is determined in step S16 that the cooling operation has not been instructed, the control unit 50 ends the 1 st start control. In this case, the operation other than the heating operation and the cooling operation is, for example, a dehumidification operation.

According to the present embodiment, the following advantageous effects are obtained.

(1-1) the control unit 50 executes either the 1 st protection control or the 2 nd protection control using the map MP1 or the map MP2 during the cooling operation or the heating operation. The time from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 2 nd protection control is shorter than the time from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 1 st protection control. According to this configuration, by executing the 2 nd protection control, the time from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN becomes short. This makes it possible to accelerate the start of the cooling operation or the heating operation. As a result, the time from the start of the cooling operation or the heating operation until the indoor temperature DA reaches the set temperature can be shortened, and therefore, the heating capacity or the cooling capacity can be improved.

(1-2) the 1 st target frequency FA1 in the 2 nd protection control is greater than the 1 st target frequency FX1 in the 1 st protection control, and the 2 nd target frequency FA2 in the 2 nd protection control is greater than the 2 nd target frequency FX2 in the 1 st protection control. According to this configuration, the number of target frequencies set from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 2 nd protection control is smaller than the number of target frequencies set from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 1 st protection control. Therefore, the time from the start of the compressor 11 to the time when the operating frequency of the compressor 11 reaches the required operating frequency FN is shortened by the 2 nd protection control, and therefore, the start of the cooling operation or the heating operation can be speeded up.

(1-3) the 1 st period TA1 of the 2 nd protection control, which is controlled such that the operating frequency of the compressor 11 maintains the 1 st target frequency FA1, is shorter than the 1 st period TX1 of the 1 st protection control, which is controlled such that the operating frequency of the compressor 11 maintains the 1 st target frequency FX 1. The 2 nd period TA2 in the 2 nd protection control, which is controlled such that the operating frequency of the compressor 11 maintains the 2 nd target frequency FA2, is shorter than the 2 nd period TX2 in the 1 st protection control, which is controlled such that the operating frequency of the compressor 11 maintains the 2 nd target frequency FX 2. According to this configuration, the number of target frequencies set from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 2 nd protection control is smaller than the number of target frequencies set from the start of the compressor 11 until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 1 st protection control. Therefore, the time from the start of the compressor 11 to the time when the operating frequency of the compressor 11 reaches the required operating frequency FN is shortened by the 2 nd protection control, and therefore, the start of the cooling operation or the heating operation can be speeded up.

(1-4) the control unit 50 selects one of the 1 st protection control and the 2 nd protection control using the map MP1 during the cooling operation, and selects one of the 1 st protection control and the 2 nd protection control using the map MP2 during the heating operation. In this way, the condition for executing the 2 nd protection control during the cooling operation and the condition for executing the 2 nd protection control during the heating operation are different from each other. That is, these conditions are set individually during the cooling operation and the heating operation. Therefore, the control unit 50 can appropriately execute the 2 nd protection control during the cooling operation or the heating operation.

(1-5) the conditions for executing the 2 nd protection control in fig. MP1 and MP2 are determined by the indoor temperature DA, the outdoor air temperature DOA, and the difference between the indoor and outdoor temperatures. In this way, the conditions for executing the 2 nd protection control are set using the indoor temperature sensor 52 and the outdoor temperature sensor 53 that are provided in the air conditioner 1 in a standard manner. Therefore, since the indoor temperature DA and the outdoor temperature DOA, which are easily obtained as information of the air conditioner 1, are used, it is not necessary to have a dedicated sensor to set the condition for executing the 2 nd protection control. Therefore, an increase in the cost of the air conditioner 1 can be suppressed.

(embodiment 2)

An air conditioning apparatus 1 according to embodiment 2 will be described with reference to fig. 1 and 8. The air conditioner 1 of the present embodiment differs from the air conditioner 1 of embodiment 1 in the content of the 1 st start control. In the following description, the components of the air conditioner 1 are the components of the air conditioner 1 shown in fig. 1.

When the operation of the air conditioner 1 is stopped, the refrigerant may condense and accumulate at a lower temperature of the indoor air temperature and the outdoor air temperature. In the case where the temperature of the outdoor air is lower than that of the indoor air, a so-called stagnation phenomenon occurs in which the liquid refrigerant is dissolved and accumulated in the lubricating oil in the compressor 11 or the liquid refrigerant is accumulated in the outdoor heat exchanger 13. When the compressor 11 is started by the heating operation in a state where the stagnation phenomenon occurs, if the increase rate of the operating frequency of the compressor 11 is increased, oil foam is likely to be generated in the compressor 11, which causes a failure of the compressor 11. In addition, even when the compressor 11 is started by the cooling operation in a state where the stagnation phenomenon is generated, oil foam is likely to be generated in the compressor 11 when the increase rate of the operating frequency of the compressor 11 is increased, as in the heating operation.

Therefore, the control portion 50 performs the refrigerant discharge starting operation to avoid the malfunction of the compressor 11 at the start of the cooling operation or the heating operation due to the stagnation phenomenon. In the refrigerant discharge start operation at the start of the heating operation, the controller 50 operates the compressor 11 in a state in which the four-way switching valve 12 is switched to the reverse cycle (cooling mode connection state) for the entire predetermined time (for example, 1 minute) at the start of the compressor 11 in association with the start of the heating operation. Thereby, the liquid refrigerant accumulated in the outdoor heat exchanger 13 is caused to flow into the indoor heat exchanger 21. The liquid refrigerant in the indoor heat exchanger 21 is evaporated by the indoor heat exchanger 21 during the refrigerant discharge start operation to become a gas refrigerant, and is sucked into the compressor 11. This can suppress the occurrence of oil foam in the compressor 11. In the refrigerant discharge start operation at the start of the cooling operation, the controller 50 operates the compressor 11 in a state in which the four-way switching valve 12 is switched to the reverse cycle (heating mode connection state) for the entire predetermined time (for example, 1 minute) at the start of the compressor 11 in association with the start of the operation of the cooling operation. Thereby, the liquid refrigerant accumulated in the indoor heat exchanger 21 is caused to flow to the outdoor heat exchanger 13. The liquid refrigerant in the outdoor heat exchanger 13 is evaporated by the outdoor heat exchanger 13 during the refrigerant discharge start-up operation to become a gas refrigerant, and is sucked into the compressor 11. This can suppress the occurrence of oil foam in the compressor 11. In this way, when the refrigerant discharge start-up operation is performed at the start of the cooling operation or the heating operation, the possibility of occurrence of a trouble in the compressor 11 becomes low.

In view of this, in the present embodiment, when the refrigerant discharge start-up operation is performed, the control unit 50 executes the 2 nd start-up control for selecting the 2 nd protection control after the refrigerant discharge start-up operation. The processing procedure of the 2 nd activation control will be described with reference to fig. 8.

The control unit 50 determines in step S21 whether or not the refrigerant discharge start operation is performed. If it is determined at step S21 that the refrigerant discharge starting operation is being performed (yes at step S21), the controller 50 determines at step S22 whether the refrigerant discharge starting operation is ended. If the control unit 50 determines in step S22 that the refrigerant discharge activation operation has ended (yes in step S22), the 2 nd protection control is selected in step S23. On the other hand, if the controller 50 determines in step S22 that the refrigerant discharge activation operation has not been completed (no in step S22), the process proceeds to the determination in step S22 again.

On the other hand, if the control unit 50 determines in step S21 that the refrigerant discharge activation operation is not being executed (no in step S21), the control unit shifts to the 1 st activation control in step S24. Then, the control unit 50 selects one of the 1 st protection control and the 2 nd protection control in accordance with the 1 st activation control.

(2-1) the control unit 50 executes the 2 nd protection control when the refrigerant discharge start operation is executed. After the refrigerant discharge start operation is completed, the possibility of occurrence of a failure of the compressor 11 is low. Therefore, by executing the 2 nd protection control after the refrigerant discharge start operation, the operating frequency of the compressor 11 can be quickly set to the required operating frequency FN after the refrigerant discharge start operation. Therefore, the start of the cooling operation or the heating operation can be speeded up.

(modification example)

The description of the embodiments is an example of the form that the air conditioner according to the present invention can take, and is not intended to limit the form. The air conditioner according to the present invention can take the form of, for example, the following modifications and combinations of at least 2 modifications that are not mutually inconsistent, other than the above-described embodiments.

In each of the above embodiments, the control of the compressor 11 when the operating frequency of the compressor 11 is increased to the required operating frequency FN in the 2 nd protection control can be arbitrarily changed. That is, this control can be arbitrarily changed under the condition that the time until the operating frequency of the compressor 11 in the 2 nd protection control reaches the required operating frequency FN is shorter than the time until the operating frequency of the compressor 11 in the 1 st protection control reaches the required operating frequency FN. The 2 nd protection control can be changed as shown in (a) to (F) below, for example. (A) The 1 st and 2 nd target frequencies FA1 and FA2 can be arbitrarily changed. For example, the 1 st target frequency FA1 may be a different value than the 2 nd target frequency FX 2. In one example, the 1 st target frequency FA1 may be a value greater than the 2 nd target frequency FX2 and less than the 3 rd target frequency FX 3. Further, for example, the 2 nd target frequency FA2 may be equal to the 4 th target frequency FX 4. (B) The 1 st period TA1 during which the compressor 11 maintains the 1 st target frequency FA1 and the 2 nd period TA2 during which the 2 nd target frequency FA2 is maintained may be equal to the 1 st to 4 th periods TX1 to TX4 of the 1 st protection control or may be longer than the 1 st to 4 th periods TX1 to TX 4. (C) The 1 st period TA1 during which the compressor 11 maintains the 1 st target frequency FA1 and the 2 nd period TA2 during which the 2 nd target frequency FA2 is maintained can be arbitrarily changed. For example, TA1 during period 1 and TA2 during period 2 may be different from each other. That is, the 1 st period TA1 and the 2 nd period TA2 can be set independently. (D) The number of target frequencies in the 2 nd protection control is not limited to 2, and can be arbitrarily changed. That is, the number of target frequencies in the 2 nd protection control may be 1 or 3 or more. (E) The contents of (A) to (D) above may be combined with each other. (F) The operating frequency of the compressor 11 may be set to the necessary operating frequency FN at the start of the 2 nd protection control. That is, the 1 st target frequency FA1 or the like may be omitted.

In each of the above embodiments, the control of the compressor 11 when the operating frequency of the compressor 11 is increased to the required operating frequency FN in the 1 st protection control may be changed as follows, for example. (G) The 1 st to 4 th target frequencies FX1 to FX4 can be arbitrarily changed. For example, the difference between the 2 nd target frequency FX2 and the 1 st target frequency FX1 and the difference between the 3 rd target frequency FX3 and the 2 nd target frequency FX2 may be different from each other. The difference between the 4 th target frequency FX4 and the 3 rd target frequency FX3 and the difference between the 3 rd target frequency FX3 and the 2 nd target frequency FX2 may be different from each other. (H) The compressor 11 can be arbitrarily changed to maintain the 1 st to 4 th target frequencies FX1 to FX4, i.e., the 1 st to 4 th periods TX1 to TX4, respectively. For example, a part of TX1 to TX4 during 1 to 4 th periods may be different from the rest of TX1 to TX4 during 1 to 4 th periods. (I) The number of target frequencies in the 1 st protection control is not limited to 4, and can be arbitrarily changed. That is, the number of target frequencies in the 1 st protection control may be 3 or 5 or more.

In each of the above embodiments, the temperature DF of the discharge pipe of the compressor 11 and the outside air temperature DOA may be added to the conditions for selecting the 1 st protection control and the 2 nd protection control. (c1) The temperature DF of the discharge pipe is above the temperature threshold DFX (DF is not less than DFX). (c2) The outside air temperature DOA is equal to or higher than the determination temperature threshold value DOAY (DOA is not less than DOAY). (c3) The temperature difference between the temperature DF of the discharge pipe and the outside air temperature DOA is greater than or equal to a temperature difference threshold value DDY (DF-DOA is greater than or equal to DDY).

The temperature threshold DFX is a threshold that limits the conditions for transition to the maps MP1 and MP2, and is set in advance by an experiment or the like. An example of the temperature threshold DFX is-3 ℃. The determination temperature threshold value DOAY is a determination value in which the conditions for transition to the maps MP1 and MP2 are limited, and is set in advance by an experiment or the like. An example of the determination temperature threshold value DOAY is-15 ℃. The temperature difference threshold DDY is a threshold that limits the conditions for shifting to the maps MP1 and MP2, and is set in advance by experiments or the like.

The controller 50 stores a map MP3 showing the relationship between the outside air temperature DOA and the temperature DF of the discharge pipe of the compressor 11 for selecting the 1 st protection control and the 2 nd protection control. Fig. 9 shows an example of fig. MP 3. The vertical axis of the map MP3 shows the temperature DF of the discharge pipe of the compressor 11, and the horizontal axis shows the outside air temperature DOA. In addition, the inclined line in the map MP3 shows the boundary condition of the temperature difference between the temperature DF of the discharge pipe and the outside air temperature DOA. In fig. MP3, a temperature region R3 satisfying all temperature conditions c1, c2, and c3 is shown with a white base (white removed き).

In the 1 st start-up control, when it is determined that there is an instruction for the cooling operation or the heating operation after the determination at step S11 or the determination at step S16, the control unit 50 determines whether the temperature DF of the discharge pipe and the outside air temperature DOA are within the temperature range R3. More specifically, the control unit 50 determines whether the temperature DF of the discharge pipe of the compressor 11 and the outside air temperature DOA are within the temperature range R3. When it is determined that the temperature is within the temperature range R3, that is, when it is determined that the temperature conditions c1, c2, and c3 are satisfied, the control unit 50 selects one of the 1 st protection control and the 2 nd protection control using the map MP1 when the operation of the heating operation is started, and selects one of the 1 st protection control and the 2 nd protection control using the map MP2 when the operation of the cooling operation is started. On the other hand, when determining that the temperature DF of the discharge pipe and the outside air temperature DOA are in a region other than the temperature region R3, that is, when at least one of the temperature conditions c1, c2, and c3 is not satisfied, the control unit 50 executes the 1 st protection control. As described above, by adding the relationship between the temperature DF of the discharge pipe of the compressor 11 and the outside air temperature DOA as the condition for executing the 2 nd protection control, the 2 nd protection control can be executed more appropriately during the cooling operation or the heating operation.

In the map MP3 of fig. 9, when the outdoor temperature DOA is less than the temperature range R4 of the determination temperature threshold value DOAY, the 3 rd protection control different from the 1 st protection control and the 2 nd protection control may be executed as the compressor protection control. As an example of the 3 rd protection control, the control unit 50 controls the compressor 11 such that the time until the operating frequency of the compressor 11 reaches the required operating frequency FN is longer than the time (period TX) until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 1 st protection control.

In map MP3 of fig. 9, in a temperature region R5 in which the outdoor air temperature DOA is equal to or higher than the determination temperature threshold value DOAY and lower than the determination temperature threshold value DOAY (DOAZ > DOAY) and the temperature DF of the discharge pipe of the compressor 11 is lower than the temperature threshold value DFX, the 4 th protection control different from the 1 st protection control and the 2 nd protection control may be executed as the compressor protection control. As an example of the 4 th protection control, the control unit 50 controls the compressor 11 such that the time until the operating frequency of the compressor 11 reaches the required operating frequency FN is longer than the time (period TX) until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 1 st protection control and is shorter than the time until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 3 rd protection control.

In map MP3 of fig. 9, in a temperature region R6 in which the outdoor air temperature DOA is equal to or higher than the determination temperature threshold value DOAZ and the temperature difference between the temperature DF of the discharge pipe and the outdoor air temperature DOA is smaller than the temperature difference threshold value DDY, the 5 th protection control different from the 1 st protection control and the 2 nd protection control may be executed as the compressor protection control. As an example of the 5 th protection control, the control unit 50 controls the compressor 11 such that the time until the operating frequency of the compressor 11 reaches the required operating frequency FN is longer than the time (period TX) until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 1 st protection control and is shorter than the time until the operating frequency of the compressor 11 reaches the required operating frequency FN in the 4 th protection control.

In each of the above embodiments, at least one of the temperature condition a1 during the heating operation and the temperature condition b1 during the cooling operation in the 1 st start-up control may be omitted.

In each of the above embodiments, one of the outdoor control device 16 and the indoor control device 23 may be omitted. For example, in the case where the indoor control device 23 is omitted, the indoor temperature sensor 52 is connected to the outdoor control device 16 in a wired or wireless manner. Further, the indoor blower 22 is connected to the outdoor control device 16 by a wire. In this case, the outdoor control device 16 corresponds to a control unit.

Claims

1. An air conditioning apparatus, comprising:

a compressor (11) capable of changing the operating frequency; and

a control unit (50) that executes compressor protection control for increasing the operating frequency of the compressor (11) to a required operating Frequency (FN) at the start of cooling operation or heating operation,

the compressor protection control has a1 st protection control and a2 nd protection control,

the 1 st protection control controls the operating frequency in such a manner that a time from a start of the compressor (11) until the operating frequency reaches the necessary operating Frequency (FN) is relatively long,

the 2 nd protection control controls the operating frequency in such a manner that a time from a start of the compressor (11) until the operating frequency reaches the necessary operating Frequency (FN) is relatively short,

the control unit (50) executes the 2 nd protection control when a predetermined condition is satisfied when the compressor protection control is executed.

2. The air conditioner according to claim 1,

the controller (50) sets a1 st target frequency (FA1, FX1) and a2 nd target frequency (FA2, FX2) that is higher than the 1 st target frequency (FA1, FX1) and lower than the required operating Frequency (FN) during the compressor protection control,

the control unit (50) maintains the operating frequency at the 1 st target frequency (FA1, FX1) for the entire 1 st period (TA1, TX1) and at the 2 nd target frequency (FA2, FX2) for the entire 2 nd period (TA2, TX2) to thereby increase the operating frequency in a stepwise manner,

the 1 st target frequency (FA1) in the 2 nd protection control is greater than the 1 st target frequency (FX1) in the 1 st protection control,

the 2 nd target frequency (FA2) in the 2 nd protection control is larger than the 2 nd target frequency (FX2) in the 1 st protection control.

3. The air conditioner according to claim 1 or 2,

the 1 st period (TA1) in the 2 nd protection control is shorter than the 1 st period (TX1) in the 1 st protection control,

the 2 nd period (TA2) in the 2 nd protection control is shorter than the 2 nd period (TX2) in the 2 nd protection control.

4. The air conditioner according to any one of claims 1 to 3,

the predetermined condition during the heating operation and the predetermined condition during the cooling operation are different.

5. The air conditioner according to any one of claims 1 to 4,

the prescribed conditions include a temperature of indoor air (DA), a temperature of outdoor air (DOA), and a temperature difference between the temperature of the indoor air and the temperature of the outdoor air (DA-DOA).

6. The air conditioner apparatus according to claim 5,

the predetermined condition during the heating operation is: the temperature (DA) of the indoor air is equal to or lower than a room temperature threshold (DAX1, DAX2), the temperature (DOA) of the outdoor air is equal to or higher than an outside air temperature threshold (DOAX1, DOAX2), and the temperature difference (DA-DOA) between the temperature (DA) of the indoor air and the temperature (DOA) of the outdoor air is equal to or lower than a temperature difference threshold (DDX1, DDX 2).

7. The air conditioner according to any one of claims 1 to 6,

the prescribed conditions include a temperature (DF) of a discharge pipe of the compressor and a temperature (DOA) of outdoor air.