JP2023072385A - Air conditioner and method - Google Patents

Abstract

To provide an air conditioner and a method for preforming feedback control of a compressor by using an appropriate control parameter.SOLUTION: An air conditioner 10 includes: a compressor 35 constituting a refrigeration cycle; a temperature sensor 24 measuring a temperature of an environment constituting the refrigeration cycle; and a compressor control section 234 performing feedback control of an operation of the compressor 35. The compressor control section 234 includes: manual setting means for setting a control parameter of the feedback control on the basis of operation input by a user; and automatic setting means for setting the control parameter on the basis of the temperature measured by the temperature sensor. Either means of the manual setting means and the automatic setting means can be used by switching.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to an air conditioner and method for performing PID control of a compressor.

In order to properly air-condition a space, air conditioners have been developed that PID-control the rotation frequency of a compressor.

For example, in Japanese Patent Application Laid-Open No. 9-119696 (Patent Document 1), PID control is performed using the temperature of the air-conditioned space and the temperature of the indoor heat exchanger as control amounts, and the frequency of the electric power supplied to the compressor driving motor as the operation amount. An air conditioner is disclosed. According to Patent Document 1, temperature hunting can be prevented.

However, PID control can be affected by various conditions such as the structure of the air-conditioned space, heat sources present in the space, climate, and other environmental factors. Therefore, it is preferable to appropriately set the control constants of the PID control according to the conditions, but the setting of the control constants requires expert knowledge about control. Therefore, in conventional air conditioners, it is common to use control constants set at the manufacturing stage of the apparatus, and there was no idea of changing the control constants afterward.

Therefore, the conventional air conditioner cannot perform PID control of the compressor appropriately, which sometimes causes hunting of the room temperature. Therefore, there is a demand for a further technique for appropriately PID-controlling the compressor.

JP-A-9-119696

SUMMARY OF THE INVENTION It is an object of the present invention to provide an air conditioner and method for feedback-controlling a compressor with an appropriate control constant.

That is, according to the present invention,
A compressor comprising a refrigerating cycle, a temperature sensor for measuring the temperature of an environment comprising the refrigerating cycle, and control means for feedback-controlling the operation of the compressor based on the temperature measured by the temperature sensor. A harmonizing device,
The control means is
manual setting means for setting a control constant of the feedback control based on an operation input by a user;
automatic setting means for setting the control constant based on the temperature measured by the temperature sensor;
Either means of the manual setting means and the automatic setting means can be switched and used,
An air conditioner is provided.

According to the present invention, it is possible to provide an air conditioner and method for feedback-controlling a compressor with an appropriate control constant.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows schematic structure of the air conditioning apparatus in each embodiment. The figure which shows the refrigerating cycle which comprises the air conditioner of each embodiment. FIG. 2 is a software block diagram included in the control unit of the air conditioner of each embodiment. FIG. 2 is a control block diagram in the first embodiment; FIG. 4 is a graph showing the response of PID control in the first embodiment; 4 is a flowchart showing feedback control in the first embodiment; 4 is a graph showing changes in room temperature in the air conditioner of the first embodiment; The control block diagram in 2nd Embodiment. The control block diagram in 3rd Embodiment.

Hereinafter, the present invention will be described with some embodiments, but the present invention is not limited to the embodiments described later. In addition, in each figure referred to below, the same reference numerals are used for common elements, and description thereof will be omitted as appropriate. In addition, in the following embodiments, the air conditioner 10 is described by exemplifying a room air conditioner (RAC), but the type of the air conditioner 10 is not particularly limited. It may be a multi-air conditioner (VRF) or the like. 1 to 3 illustrate configurations common to each embodiment.

FIG. 1 is a diagram showing a schematic configuration of an air conditioner 10 in each embodiment. As shown in FIG. 1, the air conditioner 10 includes an indoor unit 20, an outdoor unit 30, and a remote control 40. As shown in FIG.

The indoor unit 20 is arranged in a target space to be air-conditioned, and provides air conditioning desired by the user by means of a remote control terminal such as a remote control 40 operated by the user. The outdoor unit 30 is installed outside the target space, and includes an expansion valve 31, an outdoor heat exchanger 32, a compressor 35, and the like.

The air conditioner 10 forms a closed circuit in which an indoor unit 20 and an outdoor unit 30 are connected by piping. Refrigerant is enclosed in this closed circuit, the refrigerant circulates in the closed circuit, and a refrigerating cycle is realized by exchanging heat between the refrigerant and air. The details of the refrigeration cycle will be explained with reference to FIG. 2 below.

FIG. 2 is a diagram showing a refrigeration cycle that constitutes the air conditioner 10 of each embodiment. As shown in FIG. 2, the refrigeration cycle in the air conditioner 10 is composed of an indoor unit 20 and an outdoor unit 30, which are connected via piping.

The indoor unit 20 includes an indoor fan 21 , an indoor heat exchanger 22 , a controller 23 and a temperature sensor 24 . The outdoor unit 30 includes an expansion valve 31 , an outdoor heat exchanger 32 , an outdoor fan 33 , a four-way valve 34 and a compressor 35 . Here, the arrows in FIG. 2 indicate the direction in which the refrigerant flows when the air conditioner 10 is in cooling operation. . During heating operation, the direction of refrigerant flow is reversed from the direction indicated by the arrow in FIG.

The indoor unit 20 performs heat exchange between the air in the indoor space and the refrigerant flowing through the indoor heat exchanger 22 using the indoor fan 21, and discharges the air into the room again, thereby performing air conditioning in the indoor space. . During the cooling operation, the indoor heat exchanger 22 operates as an evaporator and exchanges heat between the low-temperature, low-pressure liquid refrigerant and the air blown from the indoor fan 21 . The indoor unit 20 can lower the temperature of the indoor space by discharging the heat-exchanged air. The refrigerant that has flowed out of the indoor heat exchanger 22 is a low-temperature, low-pressure gas refrigerant, and flows to the outdoor unit 30 via the refrigerant pipe.

The control unit 23 controls the operation of each piece of hardware constituting the air conditioning apparatus 10 based on a signal received from the remote controller 40 or the like, for example. As a result, the air conditioner 10 can perform predetermined operation operations desired by the user, such as cooling operation, dehumidifying operation, and heating operation. As an example, the control unit 23 can be configured as an information processing device such as a CPU.

The temperature sensor 24 is a sensor that measures the temperature that is the target of PID control. be able to. The temperature sensor 24 outputs measured temperature data to the control unit 23 . Thereby, the controller 23 can perform PID control based on the measured temperature. Note that the indoor unit 20 may be provided with a plurality of temperature sensors 24 .

Next, the outdoor unit 30 will be explained. The compressor 35 is driven by a motor to compress the low-temperature, low-pressure gas refrigerant that has flowed in from the outdoor unit side, and discharge it as a high-temperature, high-pressure gas refrigerant. Note that the operating frequency of the compressor 35 according to the described embodiment is controlled by a drive signal from the control unit 23 . Gas refrigerant discharged from the compressor 35 passes through the four-way valve 34 and flows into the outdoor heat exchanger 32 . The outdoor heat exchanger 32 exchanges heat between the refrigerant flowing inside and the outside air sent from the outdoor fan 33 . During cooling operation, the outdoor heat exchanger 32 operates as a condenser and discharges the refrigerant as a high-temperature liquid through heat exchange. Note that the outdoor heat exchanger 32 operates as an evaporator during heating operation.

The refrigerant discharged from the outdoor heat exchanger 32 is expanded in volume by the expansion valve 31 and is decompressed to lower its temperature. After that, the refrigerant flows into the indoor unit 20, and the cooling operation is performed to lower the temperature of the indoor space as described above.

The four-way valve 34 is a valve that switches the refrigerant flow path according to the operation mode of the air conditioner 10 . That is, the connection is as shown by the solid line in FIG. 2 during the cooling operation, and the connection is as shown by the broken line during the heating operation. As a result, one of the indoor heat exchanger 22 and the outdoor heat exchanger 32 can be operated as a condenser, and the other can be operated as an evaporator, and appropriate air conditioning operation can be performed.

Next, the control unit 23 that performs PID control in the described embodiment will be described with reference to FIG. FIG. 3 is a software block diagram included in the controller 23 of the air conditioner 10 of each embodiment. The control unit 23 includes functional units of a target temperature setting unit 231 , a temperature acquisition unit 232 , a control constant setting unit 233 and a compressor control unit 234 . Each of these functional means may be realized by a program stored in a storage area, a circuit, or the like.

The target temperature setting unit 231 is means for setting a target temperature that is a parameter in feedback control by PID control. For example, in the case of PID control based on room temperature, the target temperature setting unit 231 sets the temperature set by the remote controller 40 as the target temperature. Further, for example, in the case of PID control based on the temperature of the refrigerant in the indoor heat exchanger 22, the target temperature setting unit 231 sets the refrigerant evaporation temperature (for cooling operation) or condensation temperature (for heating operation) as a target. Set as temperature.

The temperature acquisition unit 232 is means for acquiring the measured value measured by the temperature sensor 24 . The control constant setting unit 233 is means for setting control constants in PID control. Note that the control constant may be set automatically based on the temperature measurement value acquired by the temperature acquisition unit 232, or may be set manually. As an example of manual setting, there is a case where an operator having specialized knowledge performs the setting when inspecting the air conditioner 10, but the embodiment is not particularly limited.

The compressor control unit 234 is means for calculating the operating frequency of the compressor 35 based on the control constant set by the control constant setting unit 233, the set temperature, and the measured temperature, and controlling the operation of the compressor 35.

Note that the software blocks described above correspond to functional means that are realized by causing each piece of hardware to function as a result of the CPU or the like executing the program according to the embodiments to be described. Also, the functional means shown in each embodiment may be implemented entirely in software, or part or all of them may be implemented as hardware that provides equivalent functions. Therefore, the air conditioner 10 may be provided with a CPU, a circuit, a storage area, etc. for realizing these processes. In addition, the air conditioner 10 may include communication means in order to implement all or part of these functions in an external server, cloud, or the like via a communication network.

So far, the configuration common to each embodiment has been described. More specific embodiments are described below.

First, the first embodiment will be explained. In the first embodiment, PID control is performed based on room temperature. FIG. 4 is a control block diagram in the first embodiment.

As shown in FIG. 4, the remote control 40 outputs the desired room temperature arbitrarily set by the user in the target space as the set temperature. Also, the temperature acquisition unit 232 acquires the measured value by the temperature sensor 24 and outputs it as the room temperature. A difference between the set temperature and the room temperature is output to the compressor control section 234 .

The control constant setting section 233 outputs the set control constants to the compressor control section 234 . When the control constant setting unit 233 is in the automatic setting mode, the control constant setting unit 233 calculates control constants in PID control based on the indoor temperature output by the temperature acquisition unit 232 . When the control constant setting unit 233 is in the manual setting mode, the control constant setting unit 233 determines control constants in PID control based on setting information received from the user. Selection between the automatic setting mode and the manual setting mode can be performed from the remote controller 40, for example.

Further, when the control constant setting unit 233 is in the manual setting mode, the control constants of the proportional term, the integral term, and the differential term can be set by the user's operation. In the manual setting mode, for example, a method in which the user arbitrarily sets a control constant using the remote controller 40, a method in which the user selects a control constant set at the time of device development, and a method in which a control constant corresponding to the operation mode is selected by selecting various operation modes. A combination of the control constants of the proportional term, the integral term, and the differential term can be set by the method of setting . For example, the user selects a controller such as the remote control 40 from a plurality of operating modes in which sets of values such as control constants K _p , K _i , and K _d are adjusted in advance according to high load and low load. The control constant can be set by selecting the mode from . In this case, in the operation mode corresponding to the case where the load is large and it is desired to lower the indoor temperature quickly, a combination with a large control constant _Ki may be selected so that the output can be easily generated with respect to the control amount. Expert knowledge about control is required to set the control constants. can be set. As a result, even in the automatic setting mode, the control constants can be easily changed by manual setting even when the temperature adjustment is not stable due to various conditions, or even when the automatic setting environment does not suit the user's preference.

Compressor control unit 234 outputs a manipulated variable for PID-controlling the operating frequency of compressor 35 based on the difference between the set temperature and the room temperature and the control constant set by control constant setting unit 233 .

Next, the operation amount by PID control of the compressor 35 and the control constant in PID control will be described. The manipulated variable u _n of the compressor 35 can be calculated by the following equation (1).

Here, u _n-1 is the manipulated variable in the previous PID control, and Δu is given by the following equation (2).

In equation (2), e _n , e _n-1 , and e _n-2 indicate the control amount (for example, the room temperature in the case of the first embodiment) during the current, previous, and two previous PID controls, respectively, and K _p , K _i , and K _d represent the constant of the proportional term, the constant of the integral term, and the constant of the differential term, respectively.

In the first embodiment to be described, the control constant setting unit 233 sets K _p , K _i , and K _d based on the room temperature, thereby appropriately operating the compressor 35 according to the environment of the target space. It is possible to prevent indoor temperature hunting. The control constant setting unit 233 in the first embodiment sets the control constant K _p , K _i , K _d can be set.

That is, the control constants K _p , K _i and K _d can be set based on the graph shown in FIG. FIG. 5 is a graph showing the response of PID control in the first embodiment. In the graph of FIG. 5, the vertical axis indicates the controlled variable (room temperature in the case of the first embodiment) and the horizontal axis indicates time t, and the compressor 35 starts operating at t=0.

As shown in FIG. 5, generally, even if the compressor 35 starts, the indoor temperature does not change immediately, and it takes a certain amount of time for the indoor temperature to be affected by the operation of the compressor 35 . Here, the line extending the slope when the control amount varies linearly after the start of control (t=0) intersects with the line extending the control amount at the start of control (t=0). When the time until L is the dead time L and the slope of the control amount in the linear variation is the maximum slope R, the control constant setting unit 233 sets the control constants K _p , K _i , K of the proportional term, the integral term, and the differential term. _d is calculated by the following formula (3). Note that a, b, and c in equation (3) indicate coefficients.

The control constant setting section 233 outputs the control constant calculated by the equation (3) to the compressor control section 234 . Compressor control unit 234 applies the output control constants to equations (1) and (2) to calculate the operating frequency of compressor 35 , that is, the amount of operation, and controls the operation of compressor 35 .

By performing PID control using the control constants calculated based on the maximum slope R and the dead time L in this way, the compressor control unit 234 in the first embodiment takes into account how easily the room temperature fluctuates. can be used to control the compressor 35 . As a result, the air conditioning apparatus 10 can prevent hunting of the indoor temperature, which is the control target, and can perform efficient air conditioning.

Next, feedback control in the first embodiment will be described. FIG. 6 is a flow chart showing feedback control in the first embodiment. The processing shown in FIG. 6 is mainly performed by the control unit 23 .

The control unit 23 starts processing from step S1000. At step S<b>1001 , the control unit 23 starts the compressor 35 . In starting control, from the viewpoint of ensuring the reliability of the compressor 35, the compressor 35 is operated at a higher rotation speed than during steady operation for a certain period of time.

Next, in step S<b>1002 , the temperature acquisition unit 232 acquires the indoor temperature measured by the temperature sensor 24 . After that, the control constant setting unit 233 calculates a control constant for PID control in step S1003. The control constant setting section 233 outputs the calculated control constants to the compressor control section 234 . That is, in the described embodiment, after shifting to normal control, the operation of the compressor 35 is controlled using the control constant calculated based on the temperature change during the start control.

Compressor control unit 234 calculates the operating frequency of compressor 35 as a manipulated variable based on the calculated control constant in step S<b>1004 , and controls the operation of compressor 35 .

After step S1004, the process proceeds to step S1005 and ends. By performing the processing described above, the control unit 23 can perform PID control using the room temperature as the controlled variable. By the processing shown in FIG. 6, PID control can be performed with appropriately set control constants, and the air conditioner 10 can perform air conditioning while preventing indoor temperature hunting.

FIG. 7 shows an example of an air conditioner 10 that performs PID control by applying the first embodiment. FIG. 7 is a graph showing changes in room temperature by the air conditioner 10 of the first embodiment. The solid line in FIG. 7 indicates the room temperature when PID control is performed by adjusting the control constant according to the method of the first embodiment, and the dashed line indicates the room temperature when PID control is performed without adjusting the control constant. .

As shown in FIG. 7, by applying the method according to the first embodiment, hunting of the room temperature is suppressed, and the room temperature approaches the set temperature in a short period of time. Therefore, it was shown that efficient air conditioning can be performed by applying the first embodiment.

So far, the first embodiment has been described. Next, a second embodiment will be described. In the second embodiment, the temperature of the refrigerant in the indoor heat exchanger 22 is used as the controlled variable in the PID control. In the following description of the second embodiment, matters common to the first embodiment will be omitted as appropriate.

FIG. 8 is a control block diagram in the second embodiment. In the second embodiment, the target temperature setting unit 231 calculates the target value of the coolant temperature, which is the controlled variable, and outputs it as the set temperature. The refrigerant temperature, which is the target value, may be calculated from the room temperature setting by the remote controller 40, or may be directly input.

Also, the temperature acquisition unit 232 in the second embodiment acquires the temperature of the refrigerant from the temperature sensor 24 installed near the indoor heat exchanger 22 . Here, the temperature acquisition unit 232 acquires the evaporation temperature of the refrigerant when the air conditioner 10 is in cooling operation, and acquires the condensation temperature of the refrigerant when the air conditioner 10 is in heating operation. . The temperature acquisition section 232 outputs the acquired temperature to the control constant setting section 233 .

The control constant setting unit 233 sets a control constant in PID control based on the acquired coolant temperature. The control constant in the second embodiment is calculated from equation (3) based on the dead time L and the maximum gradient R of the coolant temperature, as in the method described in the first embodiment. The control constant setting section 233 outputs the calculated control constants to the compressor control section 234 .

Compressor control unit 234 outputs a manipulated variable for PID-controlling the operating frequency of compressor 35 based on the difference between the set temperature and the refrigerant temperature and the control constant set by control constant setting unit 233 .

In this way, in the second embodiment, the control constant is set using the refrigerant temperature as the controlled variable, and PID control is performed. As a result, hunting of the refrigerant temperature can be prevented, and by extension, hunting of the room temperature can be prevented to perform air conditioning.

Next, a third embodiment will be described with reference to FIG. FIG. 9 is a control block diagram in the third embodiment. 3rd Embodiment is PID control of the compressor 35 in the air conditioner 10 provided with the several indoor unit 20 with respect to the one outdoor unit 30. FIG. For example, in the case of an air conditioner 10 including a plurality of indoor units 20 such as VRF, the compressor 35 is controlled as in the third embodiment. When trying to PID control the compressor 35 when a plurality of indoor units 20 are installed, since the conditions of the space where the indoor units 20 are installed are different, conventionally, the compressor required by each indoor unit 35 could not be operated properly, causing hunting of the room temperature. Therefore, also in the third embodiment, the control constants of PID control are appropriately set to prevent hunting.

In addition, in the third embodiment to be described, an example of PID control based on the room temperature is shown as in the first embodiment, but the embodiment is not particularly limited. Therefore, also in the third embodiment, like the second embodiment, PID control may be performed based on the coolant temperature.

A plurality of indoor units 20 according to the third embodiment each include a temperature acquisition unit 232 and a control constant setting unit 233 . Here, as shown in FIG. 9, it is assumed that there are two indoor units 20a and 20b. The number of indoor units 20 shown in FIG. 9 is an example, and the number of indoor units 20 in the third embodiment may be three or more.

In the third embodiment, each of the indoor units 20a and 20b calculates a control constant. That is, the indoor unit 20a sets a control constant based on the indoor temperature acquired by the temperature acquisition unit 232a and outputs it to the compressor control unit 234, and the indoor unit 20b sets the control constant based on the indoor temperature acquired by the temperature acquisition unit 232b. to set a control constant and output it to the compressor control unit 234 .

The compressor control unit 234 calculates the operation amount of the compressor 35 based on the control constants output by the control constant setting units 233a and 233b of the indoor units 20a and 20b, and controls the operation. If the control constants are different for each indoor unit, an average value may be obtained, or one of the control constants may be selected according to the conditions. Further, when there are three or more indoor units 20, the operation amount may be calculated by weighting the value of each control constant.

In the third embodiment described above, even when there are a plurality of indoor units 20, it is possible to appropriately set the control constant, thereby preventing hunting of the indoor temperature.

As described above, according to the first to third embodiments, it is possible to appropriately set the control constants in PID control. In particular, conventionally, expert knowledge was required to set the control constants, and it was difficult to change the control constants after installation of the air conditioner 10. However, according to the described embodiment, the control constants can be By calculating based on the maximum slope R and the dead time L, it is possible to set the control constant according to the state of the air-conditioned space. As a result, the room temperature can be quickly brought to the desired temperature, so comfortable and efficient air conditioning can be provided.

Also, in the described embodiment, the compressor 35 is PID-controlled, but the embodiment is not particularly limited. Therefore, even when PID-controlling devices related to the refrigeration cycle other than the compressor 35, the PID-control may be performed by setting the control constants by the method described above.

According to the embodiments of the present invention described above, it is possible to provide an air conditioner and method for feedback-controlling a compressor with an appropriate control constant.

Each function of the embodiment of the present invention described above can be realized by a device-executable program written in C, C++, C#, Java (registered trademark), etc. It can be stored and distributed in a device-readable recording medium such as ROM, MO, DVD, flexible disk, EEPROM (registered trademark), EPROM, etc., and can be transmitted via a network in a format compatible with other devices. .

As described above, the present invention has been described with embodiments, but the present invention is not limited to the above-described embodiments, and within the scope of embodiments that can be conceived by those skilled in the art, as long as the actions and effects of the present invention are exhibited. , are within the scope of the present invention.

10... Air conditioner,
20... indoor unit,
21... indoor fan,
22 ... indoor heat exchanger,
23 ... control unit,
24 ... temperature sensor,
30 outdoor unit,
31... expansion valve,
32 ... outdoor heat exchanger,
33... an outdoor fan,
34... four-way valve,
35 Compressor,
40 ... remote control,
231 ... target temperature setting unit,
232 ... temperature acquisition unit,
233... control constant setting unit,
234 Compressor control unit

Claims (6)

A compressor comprising a refrigerating cycle, a temperature sensor for measuring the temperature of an environment comprising the refrigerating cycle, and control means for feedback-controlling the operation of the compressor based on the temperature measured by the temperature sensor. A harmonizing device,
The control means is
manual setting means for setting a control constant of the feedback control based on an operation input by a user;
automatic setting means for setting the control constant based on the temperature measured by the temperature sensor;
Either means of the manual setting means and the automatic setting means can be switched and used,
Air conditioner. The automatic setting means is
Setting the control constant based on the temperature measured by the temperature sensor during a certain period of time from the start of the compressor;
The air conditioner according to claim 1. The automatic setting means is
The control constant is calculated based on the slope when the temperature change becomes linear and the dead time after the compressor starts,
The air conditioner according to claim 1 or 2. The temperature measured by the temperature sensor is the temperature of the air-conditioned space.
The air conditioner according to any one of claims 1 to 3. The temperature measured by the temperature sensor is the temperature of the refrigerant in the indoor heat exchanger,
The air conditioner according to any one of claims 1 to 3. The air conditioner includes a plurality of indoor units each having the control means and the temperature sensor,
The air conditioner according to any one of claims 1 to 5.

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