JP2005106429A - Control device and control method for air conditioner - Google Patents

Abstract

The present invention provides a control technique that minimizes the frequency of discontinuous switching of the compressor operation amount in an air conditioner and that can easily perform noise and vibration design.
SOLUTION: A target temperature setting means 21 for setting a target temperature r in an air-conditioning target room, a temperature detection means 22 for detecting a temperature y in the air-conditioning target room, and a temperature difference e = ry−y between the room temperature y and the target temperature r. The continuous operation amount calculation means 25 for calculating the continuous operation amount u ′ by performing a proportional operation, an integral operation, or a differential operation and adding the calculation results, and the compressor 7 set discretely Discretized table storage means 27 for storing the manipulated variable as a discretized table, and discrete manipulated variable calculating means for determining the manipulated variable of the compressor 7 corresponding to the continuous manipulated variable u ′ by referring to the discretized table. 26.
[Selection] Figure 2

Description

  The present invention relates to a control technology for controlling the operation amount of a refrigerant circulation system compressor in accordance with the room temperature to be air-conditioned in an air conditioner, and in particular, a single rotary compressor having a large vibration during low-speed rotation. TECHNICAL FIELD OF THE INVENTION

  In an inverter type air conditioner provided with a refrigerant circulation circuit, the room temperature is adjusted to a set target temperature by controlling the rotation speed (rotation frequency of the compressor) of a compressor provided in the refrigerant circulation path. A control device is used to control the compressor.

  As a method for controlling the compressor by the control device, conventionally, continuous control such as PID control and I-PD control (for example, refer to Patent Documents 1 and 2) and discontinuous control such as zone control (for example, patents). References 3 to 6) are known.

  A typical method for continuous control is PID control. FIG. 6 is a diagram showing a typical configuration of a control system of an air conditioner by PID control (see Patent Document 2 and FIG. 5). 6, the PID control system 100 includes a deviation calculator 101, a proportional calculator 102, an integrator 103, a differentiator 104, an adder 105, and a control target 106. In this case, the control object 106 is a system including a compressor, a refrigerant circulation system, a heat exchanger, and a room to be air-conditioned.

  The target temperature r is set by a remote control device installed indoors. The room temperature y is detected by a temperature sensor installed in the indoor unit of the air conditioner. The deviation calculator 101 calculates a deviation e = ry that is a difference between the target temperature r and the room temperature y. Actually, the indoor temperature y is not the temperature itself detected by the temperature sensor, but is generally corrected so that it is close to the temperature near the floor in the room in consideration of the installation height of the indoor unit of the air conditioner. Detected temperature. The proportional calculator 102 performs a proportional calculation on the deviation e. The integrator 103 performs an integration operation on the deviation e. The differentiator 104 performs a differentiation operation on the deviation e. The adder 105 adds the calculation outputs of the proportional calculator 102, the integrator 103, and the differentiator 104, and outputs the result as an operation amount u of the compressor. In the case of an inverter / air conditioner, the “operation amount” is the operating frequency of the compressor. Eventually, the operation amount u is expressed as (Equation 1).

  On the other hand, a typical discontinuous method is a zone control method. FIG. 7 is a diagram showing a typical configuration of a control system for an air conditioner based on a zone control system (see Patent Documents 3 and 5, Patent Document 6, and FIG. 1). In FIG. 7, the zone control system 110 includes a deviation calculator 111, a temperature gradient change detection unit 112, a temperature difference storage unit 113, an operating frequency calculation unit 114, a zone storage unit 115, and a control object 116. In this case, the control object 116 is a system including a compressor (including a frequency converter), a refrigerant circulation system, a heat exchanger, and a room to be air-conditioned.

  As in the case of FIG. 6, the target temperature r is set by a remote control device or the like installed indoors, and the room temperature y is detected by a temperature sensor installed in the indoor unit of the air conditioner. The deviation calculator 111 calculates a deviation e = r−y, which is a difference between the target temperature r and the room temperature y. The temperature gradient change detection unit 112 detects a change in the gradient of the room temperature based on the deviation e. The operating frequency calculation unit 114 calculates the operation amount u of the compressor based on a change in the indoor temperature gradient and a predetermined zone.

This zone represents the correspondence relationship of the operation amount u of the compressor with respect to the section of deviation e, and a predetermined table is determined in advance and stored in the zone storage means 115. FIG. 8 shows an example of the correspondence relationship between the operation amount u of the compressor and the section of deviation e in the cooling operation. In FIG. 8, the thermo-off temperature T _off is a temperature at which the compressor is stopped. The thermo-on temperature _Ton is a temperature at which the compressor is restarted. When the room temperature is decreasing, zone control is performed by the zone in the area A in FIG. Further, when the room temperature is rising, each zone in the area A is shifted up in a direction in which the deviation is large, and the zone control by the zone in the area B in FIG. 8 is performed.

  In the zone control, the deviation e between the room temperature and the target temperature is divided into zones a to h as shown in FIG. 8, and the operating frequency of the compressor is assigned to each zone. Then, the operating frequency calculation unit 114 determines which zone the deviation e belongs to, and outputs the operation amount u of the zone to which the deviation e belongs to the compressor.

When the room temperature becomes equal to or lower than the thermo-off temperature T _off by the cooling operation, the operation frequency calculation unit 114 sets the operation amount u to 0 and stops the compressor. At this time, the compressor may not be stopped immediately, but may be stopped after a certain period of time (see Patent Document 3).

When the compressor stops, the room temperature starts to rise and the deviation starts to increase. When the deviation turns in the increasing direction, the operating frequency calculation unit 114 shifts up the zones a to h by 0.5 ° C. in the direction in which the deviation is large. Then, the operating frequency calculation unit 114 monitors the deviation e. When the deviation e reaches the thermo-on temperature T _on, operation frequency calculation unit 114 restarts the operation of the compressor in operation amount corresponding to the zone c. In resuming the operation of the compressor, an operation for increasing the operation amount at an appropriate speed is performed so that the compressor does not cause hunting.
JP 54-89352 A JP-A-5-250004 Japanese Patent Laid-Open No. 9-243144 Japanese Patent Publication No.57-67735 JP 59-13841 A Japanese Examined Patent Publication No. 4-47219

  In continuous control such as the above-described conventional PID control and I-PD control, the air conditioning load in the room changes when the target temperature r changes due to a setting change, or when the window of the room is opened or the day begins to enter the room. In some cases, the rotation speed (operation amount) of the compressor continuously changes following the target temperature and the air conditioning load. When the room temperature reaches the vicinity of the target temperature, the rotation speed of the compressor becomes a value near zero.

  By the way, generally, when the rotational speed of the compressor becomes low, the compressor and other devices tend to cause mechanical resonance. And when a compressor etc. produce mechanical resonance, a vibration and noise will generate | occur | produce or rotation of a compressor will become unstable. Therefore, in designing the air conditioner, a design with special measures is required so that the rotation speed of the compressor does not stop at the resonance point. For this reason, there is a problem that the burden of designing spent on countermeasures against vibration and noise is large.

  On the other hand, in the conventional discontinuous control such as zone control, the rotation speed (operation amount) of the compressor in each zone can be determined in advance to a specific discrete value. Therefore, by setting the rotation speed of the compressor in each zone while avoiding resonance points that cause mechanical resonance, there is no problem of design burden as in the continuous control.

  On the other hand, in the conventional zone control, when the room temperature reaches the target temperature, the rotation speed of the compressor becomes the lowest, and when the thermo-off temperature is exceeded, the compressor stops. Such control functions without problems when the air conditioning load (heat input / output) in the room to be air-conditioned is sufficiently small relative to the air conditioning capacity of the air conditioner. However, if the air conditioning load in the room subject to air conditioning is not sufficiently small relative to the air conditioning capacity of the air conditioner, for example, if the room is large or the room has large windows and the sun is coming in When the compressor stops, the room temperature changes quickly. When the room temperature passes the thermo-on temperature, the compressor starts again. When the compressor is activated and air conditioning is started, the room temperature immediately passes the thermo-off temperature and the compressor stops.

  FIG. 9 is a diagram showing the correspondence between changes in room temperature and changes in the rotational speed of the compressor in conventional zone control. As shown in FIG. 9, when the air conditioning load is not considered to be sufficiently small, the compressor is frequently turned on / off and the number of rotations is switched. When the rotation speed of the compressor is changed, the temperature of the air blown from the air conditioner changes discontinuously, so that the user easily feels uncomfortable. Further, when the rotation speed of the compressor changes, the sound generated by the air conditioner also changes. Normally, the sound generated from the air conditioner is designed to be as small as possible. However, even if the sound is small, if the volume changes discontinuously, it becomes annoying to the user and the comfort of the room is impaired.

  Accordingly, an object of the present invention is to provide an air conditioner control technology that minimizes the frequency of discontinuous switching of the operation amount in the compressor of the air conditioner and can easily perform noise and vibration design. It is to provide.

  A first configuration of an air conditioner control device according to the present invention is a control device that calculates an operation amount of a compressor in an air conditioner, and sets a target temperature in a room to be air-conditioned. Proportional to the temperature difference between the means, the temperature detection means for detecting the temperature of the room to be air-conditioned, and the indoor temperature detected by the temperature detection means and the target temperature set by the target temperature setting means Performs an operation, integration operation, or differentiation operation, and adds the operation results to obtain a continuous operation amount calculation means for calculating a continuous operation amount, and discretizes the operation amount of the compressor set discretely Discretized table storage means for storing as a table, and discrete manipulated variable calculating means for determining the manipulated variable of the compressor corresponding to the continuous manipulated variable by referring to the discrete table. And wherein the door.

  With this configuration, the steady value of the manipulated variable is obtained by the continuous manipulated variable calculating means by feedback control using the added value of the proportional difference calculation, integral calculation, or differential calculation of the temperature difference. Therefore, since the steady value of the manipulated variable is determined to reflect the degree of change in the room temperature relative to the change in the manipulated variable, depending on the air conditioning load conditions in the room, such as the size of the room, the entrance and exit of heat from the outside to the room, The steady value of the manipulated variable is determined. Therefore, even when the target temperature and air conditioning load conditions change, if a certain settling time elapses, the fluctuation in the amount of operation of the compressor required for air conditioning control changes with a small amplitude around a constant steady value. To come. As a result, zone switching does not occur frequently as in the conventional zone control system, and the frequency of fluctuations in the temperature of the blown air from the indoor units and the fluctuation in the generated sound volume is reduced.

  Further, the operation amount of the compressor is a discrete operation amount corresponding to the continuous operation amount calculated by the continuous operation amount calculation means from among the operation amount values registered in advance in the discretization table by the discrete operation amount calculation means. Set to the correct value. Therefore, by setting the operation amount registered in advance in the discretization table to an operation amount other than the resonance point of the compressor, it is possible to easily avoid the vibration and noise of the air conditioner from increasing. is there. In other words, the design burden that is spent on vibration countermeasures and noise countermeasures is reduced.

  Here, the “operation amount” refers to an amount (parameter) that can control the output of the compressor, such as the rotational speed, torque, and power consumption of the compressor. As the “target temperature setting means”, a remote controller or the like installed in the room is used. As the “temperature detection means”, a temperature sensor such as a thermistor or a thermocouple installed in the room is used. “Continuous operation amount” refers to an operation amount calculated as a continuous value. As a method of “calculating the continuous operation amount”, a general control method such as PID control, PI control, or I-PD control can be used. “The operation amount of the compressor set discretely” refers to the operation amount set not as a continuous value but as a discrete value. The discrete operation amount is usually set to a value that avoids the resonance point of the compressor. “The operation amount of the compressor corresponding to the continuous operation amount” is the one that is closest to the continuous operation amount among the discrete operation amounts, or the continuous operation amount is rounded down or rounded up to the discrete operation amount. What you get.

  According to a second configuration of the control device for an air conditioner according to the present invention, in the first configuration, the continuous operation amount calculation means is based on the temperature difference by PID control, PI control, or I-PD control. A continuous operation amount of the operation amount of the compressor is calculated.

  According to this configuration, the continuous operation amount calculation means calculates a continuous operation amount of the operation amount of the compressor by PID control, PI control, or I-PD control based on the temperature difference. The continuous operation amount is determined so that the deviation offset becomes 0, reflecting the rate of change of temperature and the past integrated value of the temperature difference. Therefore, after a certain settling time has elapsed, the continuous operation amount converges to a steady value that minimizes the change in the operation amount of the compressor in accordance with the set target temperature and indoor air conditioning load conditions. . Thereby, the switching of the operation amount of the compressor does not frequently occur, and the frequency of fluctuations in the temperature of wind blown out from the indoor units and the fluctuation in generated sound volume is reduced.

  According to a third configuration of the control device for an air conditioner according to the present invention, in the first or second configuration, the discrete manipulated variable calculation means includes the continuous manipulated variable among the manipulated variables in the discretization table. The operation amount that minimizes the absolute value of the difference, the operation amount that does not exceed the continuous operation amount and the maximum operation amount, or the operation amount that exceeds the continuous operation amount and the minimum operation amount, The operation amount is determined.

  With this configuration, the discrete operation amount calculation means sets the operation amount of the compressor to the value closest to the continuous operation amount or the second closest value among the operation amounts in the discretization table. As a result, the operation amount of the compressor is controlled as optimally as possible, and at the same time, the operation amount can be set while avoiding the resonance point of the air conditioner.

  According to a fourth configuration of the control device for an air conditioner according to the present invention, in any one of the first to third configurations, the discrete manipulated variable calculation means is configured such that the continuous manipulated variable is smaller than a predetermined threshold. The operation amount of the compressor corresponding to the continuous operation amount is determined by referring to the discretization table, and when the continuous operation amount is larger than a predetermined threshold, the continuous operation amount is determined as the compressor. The operation amount is determined.

  When the operation amount of the compressor is small, that is, when the rotation speed of the compressor is low, resonance is likely to occur in the air conditioner, and therefore it is preferable to perform discontinuous control such as zone control. On the other hand, when the amount of operation of the compressor is large, that is, when the rotational speed of the compressor is high, the resonance point of the air conditioner decreases, and resonance hardly occurs. Therefore, it is preferable to use continuous control from the viewpoint of shortening the settling time in the control system and improving the followability to changes in indoor air conditioning load conditions and changes in target temperature. Therefore, in the above configuration, in the region where the resonance is likely to occur and the operation amount of the compressor is small, the discrete operation amount calculation means refers to the discretization table so that the discrete operation amount corresponding to the continuous operation amount is reduced. In a region where discontinuous control is performed by determining the operation amount, resonance does not occur, and the operation amount of the compressor is large, the discrete operation amount calculation means determines the continuous operation amount as the operation amount of the compressor. Therefore, continuous control is performed. As a result, it is possible to reduce the settling time of the control system and improve the followability with respect to the air conditioning load change and the target temperature change, and at the same time, it is possible to reduce vibration and noise during the low output operation of the compressor.

  A first configuration of an air conditioner control method according to the present invention is a control method for calculating an operation amount of a compressor in an air conditioner, and includes a temperature detection unit installed in a room to be air-conditioned. Performs proportional, integral, or differential calculations on the temperature difference between the detected indoor temperature and the target indoor temperature that is the target of air conditioning, and calculates the amount of continuous operation by adding the calculation results. And a second step of determining an operation amount of the compressor corresponding to the continuous operation amount by referring to a discretization table that holds the operation amount of the compressor set discretely. It is characterized by providing.

  In a second configuration of the air conditioner control method according to the present invention, in the first step of the first configuration, the compression is performed by PID control, PI control, or I-PD control based on the temperature difference. The continuous operation amount of the operation amount of the machine is calculated.

  According to a third configuration of the air conditioner control method of the present invention, in the second step of the first or second configuration, the discretization table is used when the continuous operation amount is smaller than a predetermined threshold value. , The operation amount of the compressor corresponding to the continuous operation amount is determined, and when the continuous operation amount is larger than a predetermined threshold, the continuous operation amount is determined as the operation amount of the compressor. It is characterized by doing.

As described above, according to the present invention, by using the feedback control using the added value of the proportional calculation, integral calculation, or differential calculation of the temperature difference, the steady value of the manipulated variable according to the indoor air conditioning load condition After the settling time elapses, the fluctuation of the operation amount of the compressor changes with a small amplitude around a constant steady value. Therefore, the frequency of zone switching decreases, and the frequency of fluctuations in the blowout temperature of the indoor unit and the fluctuations in the generated volume decreases. Therefore, it is possible to prevent an unpleasant feeling due to fluctuations in the temperature of the blown air and fluctuations in the generated volume from becoming annoying.
In addition, by setting the discrete value corresponding to the continuous manipulated variable calculated by the continuous manipulated variable calculating means from among the manipulated variable values registered in advance in the discretization table, the air conditioner can be designed. Since the burden of vibration countermeasures and noise countermeasures is reduced, the development time of the air conditioner can be shortened and the development cost can be reduced.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of the entire system of an air conditioner according to Embodiment 1 of the present invention. The air conditioner 1 is composed of two parts, an outdoor unit 2 and an indoor unit 3. Further, a refrigerant circulation path 4 through which refrigerant circulates between the outdoor unit 2 and the indoor unit 3 is provided. The outdoor unit 2 is installed outside and performs heat exchange between the refrigerant in the refrigerant circuit 4 and the outdoor air. In addition, the indoor unit 3 is installed in a room to be air-conditioned, and performs heat exchange between the refrigerant in the refrigerant circulation path 4 and the air in the room.

  The refrigerant circulation path 4 includes an outdoor heat exchanger 5 → four-way valve 6 → compressor 7 → (four-way valve 6 →) muffler 9 → indoor heat exchanger 8 → strainer 10 → electronic expansion valve 11 → capillary tube 12 → outdoor. Each device is provided in the order of the heat exchanger 5. The outdoor heat exchanger 5, the four-way valve 6, the compressor 7, the muffler 9, the strainer 10, the electronic expansion valve 11, and the capillary tube 12 are provided inside the outdoor unit 2, and the indoor heat exchanger 8 It is provided inside the machine 3.

  The outdoor heat exchanger 5 performs heat exchange between the refrigerant and the outdoor air. The four-way valve 6 switches the refrigerant circulation direction. As the compressor 7, a single rotary compressor, a twin rotary compressor, or the like is used. The compressor 7 pressurizes and circulates the refrigerant in the refrigerant circulation path 4. The indoor heat exchanger 8 performs heat exchange between the refrigerant and the indoor air. The muffler 9 silences the sound generated in the refrigerant circulating in the refrigerant circuit 4. The strainer 10 removes dust floating in the refrigerant circulation path 4 with a filter. The electronic expansion valve 11 functions as a refrigerant depressurization mechanism that depressurizes the refrigerant in the refrigerant circulation path 4 using a throttle. The capillary tube 12 reduces refrigerant flow noise when passing through the electronic expansion valve 11.

  The direction in which the refrigerant circulates in the refrigerant circulation path 4 can be switched by the four-way valve 6. When the refrigerant is circulated in the direction of the arrow A, the air conditioner 1 functions as a cooling device, and when the refrigerant is circulated in the direction of the arrow B, the air conditioner 1 functions as a heating device.

  An outdoor unit control unit 13 that controls the operation of the outdoor unit 2 is provided inside the outdoor unit 2. The outdoor unit control unit 13 can perform inverter control of the compressor 7. An indoor unit control unit 14 that controls the operation of the indoor unit is provided inside the indoor unit 3. In the indoor unit 3, a crossflow fan 15 is provided for sending indoor air to the indoor heat exchanger 8 and blowing out the air indoors. An indoor temperature sensor 16 such as a thermistor is provided at the suction port of the crossflow fan 15. The indoor temperature sensor 16 can detect the temperature of indoor air. Further, a remote controller 17 for setting a target temperature for air conditioning is connected to the indoor unit control unit 14.

  FIG. 2 is a diagram showing a control system of the compressor 7 of the air conditioner 1 of FIG. The control system of the compressor 7 includes a control device 20, the compressor 7, a heat exchange system 29, and indoor air 30. Here, the heat exchange system is a system configured by the refrigerant circuit 4 shown in FIG. 1 and each device connected thereto. The indoor air 30 is indoor air in which the indoor unit 3 is installed.

  The control device 20 includes a target temperature setting unit 21, a temperature detection unit 22, a temperature difference calculation unit 24, a continuous operation amount calculation unit 25, a discrete operation amount calculation unit 26, a discretization table storage unit 27, and a frequency converter 28. Has been. The target temperature setting means 21 is a means for setting the air conditioning temperature (target temperature) in the room where the indoor unit 3 is installed, and is specifically realized by the remote controller 17 in FIG. The temperature detection unit 22 includes an indoor temperature sensor 16 and a temperature correction unit 23.

  The temperature correction unit 23 corrects the indoor air temperature detected by the indoor temperature sensor 16, and is specifically performed by the indoor unit control unit 14. The temperature actually detected by the indoor temperature sensor 16 is indoor air sucked into the indoor unit 3, but the indoor unit 3 is usually installed on the upper part of the indoor wall. On the other hand, the temperature of indoor air is not uniform, the temperature near the ceiling in the room is high, and the temperature near the floor is low. Therefore, the temperature correction means 23 performs correction to estimate the temperature in the vicinity of 0.5 m to 1.5 m from the indoor floor where people live, from the temperature of the air near the indoor ceiling detected by the indoor temperature sensor 16. Is.

  The temperature difference calculation means 24 has a deviation e (t) = r () between the target temperature r (t) set by the target temperature setting means 21 and the indoor air temperature y (t) detected by the temperature detection means 22. t) -y (t) is calculated. The continuous manipulated variable calculator 25 calculates the manipulated variable u ′ (t) by continuous control based on the deviation e (t) output from the temperature difference calculator 24. Here, PID control, I-PD control, PI control, or the like is used as a continuous control method performed by the continuous operation amount calculation means 25. Hereinafter, as an example, the description will be made assuming that the continuous operation amount calculation means 25 calculates the continuous operation amount u ′ (t) from the deviation e (t) by PID control.

  The “operation amount” here is a parameter for operating the compressor 7. Specifically, it is the rotation speed, frequency, or applied power of the compressor 7. In the following, it is assumed that the “operation amount” is the frequency of the compressor 7.

  The discrete manipulated variable calculator 26 discretizes the continuous manipulated variable u ′ (t) output from the continuous manipulated variable calculator 25 by referring to the discretization table stored in the discretization table storage 27. Output as a quantity u (t). The frequency converter 28 applies power proportional to the discrete manipulated variable u (t) output from the discrete manipulated variable calculating means 26 to the compressor 7. Thereby, the compressor 7 is inverter-controlled.

  The temperature difference calculating means 24, continuous manipulated variable calculating means 25, discrete manipulated variable calculating means 26, discretized table storage means 27, and frequency converter 28 are realized by the outdoor unit controller 13 in FIG. .

  In addition, the value of the operation amount to be registered in the discretization table is registered in advance so as to avoid the resonance point of the mechanical vibration of the air conditioner 1. By doing so, noise and vibration due to resonance of the air conditioner 1 can be easily avoided. In addition, it is possible to easily take measures to prevent noise and vibration due to resonance of the air conditioner 1 at the time of design.

  The control method of the air conditioner control apparatus according to this embodiment configured as described above will be described below.

  FIG. 3 is a flowchart showing the operation of the control device for the air conditioner according to the first embodiment of the present invention. First, the target temperature r is set in the target temperature setting means 21, and the time t is set to 0 in the outdoor unit controller 13 (S1). Next, the temperature detection means 22 corrects the room temperature Th detected at the time t detected by the room temperature sensor 16 by the temperature correction means 23 and outputs it to the temperature difference calculation means 24 as the room temperature y (t). To do. The temperature difference calculation means 24 subtracts the room temperature y (t) from the target temperature r (t) set by the target temperature setting means 21 at time t to detect the deviation e (t) (S2).

Next, the continuous operation amount calculation means 25 calculates the continuous operation amount u ′ (t) from (Equation 1) based on the deviation e (t) (S3). At this time, if the value of u ′ (t) calculated by (Equation 1) exceeds the maximum value u _max of the operation amount of the compressor, u ′ (t) = u _max is set.

  Next, the discrete manipulated variable calculation means 26 refers to the discretization table stored in the discretization table storage means 27, and among the operation quantities registered in the discretization table, the continuous manipulated variable u (t) is the largest. The close manipulated variable is output to the frequency converter 28 as a discrete manipulated variable u (t) (S4).

Incidentally, discretization table, time change inclination of the continuous operation amount and positive discretization table TB cases ^+, the inclination of time change of continuous operation amount discretization table TB in the case of negative ^- different two of the Use a discretization table. If during the cooling is discretized table TB ⁺ discretization table TB ^- using those continuous operation amount is shifted up to a large direction. In the case of the heating, the discrete table TB ^- is used after downshifting discretization table TB ⁺ direction continuous operation amount is small. As described above, the use of the discretization table that varies depending on the slope of the time change gradient of the continuous operation amount is because the operation amount control of the compressor 7 has a history so that the compressor immediately after the compressor is stopped. This is to avoid a situation that would cause the to start.

FIG. 4 is a diagram illustrating the relationship between the continuous operation amount u ′ and the discrete operation amount u. As shown in FIG. 4A, the continuous operation amount u ′ is divided into a plurality of sections a to f, and a discrete operation amount u determined for each section is assigned. In the section a, since the minimum operation amount u ₀ of the compressor 7 is less than or equal to 0, 0 is assigned to the discrete operation amount u. In the section f, since the maximum operation amount u ₄ of the compressor 7 is equal to or greater than the maximum operation amount u ₄ , the maximum operation amount u ₄ is assigned to the discrete operation amount u.

The correspondence relationship between the continuous operation amount u ′ and the discrete operation amount u can be as shown in FIG. That is, in a region where the continuous operation amount u ′ is small, an operation amount is assigned discretely to the discrete operation amount u as in FIG. 4A, and in a region where the continuous operation amount u ′ is a predetermined size u ₄ or more. , U = u ′ and u is a continuous value. Usually, since there are many resonance points of mechanical vibration in the region where the operation amount of the compressor 7 is small, it is suitable to assign the operation amount discretely, but in the region where the operation amount is large, the mechanical resonance point Will be less. Therefore, in such a region, it is preferable that the operation amount is a continuous value obtained by PID control because the operation amount converges faster.

  Next, the frequency converter 28 performs inverter control of the compressor 7 based on the input discrete manipulated variable u (t) (S5). Then, after the time t is incremented by 1 in the outdoor unit control unit 13 (S6), the operation returns to the operation of step S2, and the above operation is repeated again.

  FIG. 5 is a diagram illustrating an example of a transient response by the control method of the air conditioner 1 according to the first embodiment. Although FIG. 5 shows the case of cooling, the same applies to the case of heating.

When the room is narrow with respect to the air conditioning capacity of the air conditioner 1 and the air conditioning load is relatively small, the transient responses of the room temperature, the continuous operation amount, and the discrete operation amount are y ₁ and u _{1 in} FIG. ', U ₁ and so on. When the air conditioner 1 starts cooling, room temperature y ₁ is quickly approaches the target temperature. Along with this, continuous operation amount u _{1 'and} discrete operation amount u ₁ is reduced, continuous operation amount u _1' is discretized table TB ^- when it becomes smaller than the minimum value of the registered in the operation amount, discrete The manipulated variable calculation means 26 sets the value of the discrete manipulated variable u ₁ to 0, and the compressor stops.

In this case, since the air conditioning load is small, after the compressor 7 is stopped, the indoor temperature y ₁ continues to rise slowly. Along with this, the continuous operation amount u ₁ output from the continuous operation amount calculation means 25 also slowly increases. When the continuous operation amount u ₁ is larger than the minimum value u ⁺ _min of operation amount registered in the discretization table TB ^+, discrete operation amount calculation means 26 the minimum value of the discrete manipulated variables u ₁ The value u ⁺ _min is set and the compressor 7 is started. Thereafter, when the continuous manipulated variable u ₁ ′ becomes smaller than the minimum value of the manipulated variable registered in the discretization table TB ⁻ again, the discrete manipulated variable calculating means 26 sets the value of the discrete manipulated variable u ₁ to 0, The compressor stops.

  Thus, when the air conditioning load is small, air conditioning is performed by repeatedly starting and stopping the compressor 7 at relatively long intervals.

On the other hand, if the room is large with respect to the air conditioning capacity of the air conditioner 1 or there is a large window in the room and the sun is coming in from there, the air conditioning load is relatively large. The transient responses of the quantity and the discrete manipulated variable are respectively y ₂ , u ₂ ′, and u ₂ in FIG. When the air conditioner 1 starts cooling, the room temperature y ₂ is slowly approaches the target temperature. Along with this, the continuous operation amount u ₂ ′ and the discrete operation amount u ₂ decrease. However, in this case, since the continuous operation amount u ₂ ′ is determined by PID control, a steady value that finally converges is determined according to the load on the room. That is, the control is not performed so that the operation amount becomes zero as in the conventional zone control, but the control is performed toward the steady operation amount determined according to the load of the room.

Therefore, when the air conditioning load is large, the constant values continuous operation amount u _{2 'is} converged, discrete table TB ^- becomes a value larger than the minimum value of the registered in the operation amount. Therefore, the discrete operating amount calculating means 26, discrete table TB ^- among the registered in the operation amount, and outputs the closest to continuous operation amount u _{2 'as} a discrete operation amount u _1. Therefore, the compressor 7 does not stop even when it is in a steady state, and continues to operate in a thermal equilibrium state. Therefore, the fluctuation of the indoor temperature y ₂ can be minimized, and the fluctuation of the operation amount u ₂ of the compressor 7 can be minimized.

As described above, even when the air conditioning load is large, the change in the indoor temperature y _{2 and} the change in the operation amount u ₂ of the compressor 7 are small. Will no longer be given.

It is a figure showing the structure of the whole system of the air conditioner which concerns on Example 1 of this invention. It is a figure showing the control system of the compressor 7 of the air conditioner of FIG. It is a flowchart showing operation | movement of the control apparatus of the air conditioner which concerns on Example 1 of this invention. It is a figure showing the relationship between continuous manipulated variable u 'and discrete manipulated variable u. It is a figure showing an example of the transient response by the control method of the air conditioner concerning Example 1. It is a figure showing the typical structure of the control system of the air conditioner by PID control. It is a figure showing the typical structure of the control system of the air conditioner by a zone control system. It is a figure which shows an example of the correspondence of the operation amount u of the compressor with respect to the area of the deviation e. It is a figure showing the correspondence of the change of the indoor temperature in the conventional zone control, and the change of the rotation speed of a compressor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Outdoor unit 3 Indoor unit 4 Refrigerant circulation path 5 Outdoor heat exchanger 6 Four way valve 7 Compressor 8 Indoor heat exchanger 9 Muffler 10 Strainer 11 Electronic expansion valve 12 Capillary tube 13 Outdoor unit control part 14 Indoor unit Control unit 15 Cross flow fan 16 Indoor temperature sensor 17 Remote controller 20 Control device 21 Target temperature setting means 22 Temperature detection means 23 Temperature correction means 24 Temperature difference calculation means 25 Continuous operation amount calculation means 26 Discrete operation amount calculation means 27 Discretization table Storage means 28 Frequency converter 29 Heat exchange system 30 Indoor air

Claims (7)

A control device for calculating an operation amount of a compressor in an air conditioner,
Target temperature setting means for setting a target temperature in the room to be air-conditioned,
Temperature detecting means for detecting the temperature of the room to be air-conditioned,
Performing a proportional operation, an integral operation, or a differential operation on the temperature difference between the room temperature detected by the temperature detection means and the target temperature set by the target temperature setting means, and adding the calculation results A continuous operation amount calculating means for calculating a continuous operation amount;
Discretization table storage means for storing the operation amount of the compressor set discretely as a discretization table;
Discrete operation amount calculation means for determining an operation amount of the compressor corresponding to the continuous operation amount by referring to the discretization table;
A control device comprising: 2. The control according to claim 1, wherein the continuous operation amount calculation unit calculates a continuous operation amount of the operation amount of the compressor by PID control, PI control, or I-PD control based on the temperature difference. apparatus. The discrete manipulated variable calculation means is an manipulated variable in which the absolute value of the difference from the continuous manipulated variable is the smallest among the manipulated variables in the discretization table, or an manipulated variable that does not exceed the continuous manipulated variable and is the maximum The control device according to claim 1, wherein the operation amount of the compressor is determined as a minimum operation amount that exceeds the continuous operation amount. When the continuous operation amount is smaller than a predetermined threshold, the discrete operation amount calculation means determines an operation amount of the compressor corresponding to the continuous operation amount by referring to the discretization table, The control device according to any one of claims 1 to 3, wherein when the continuous operation amount is larger than a predetermined threshold, the continuous operation amount is determined as an operation amount of the compressor. A control method for calculating an operation amount of a compressor in an air conditioner,
For the temperature difference between the room temperature detected by the temperature detecting means installed in the room to be air-conditioned and the target temperature in the room to be air-conditioned, a proportional operation, an integral operation, or a differential operation is performed, A first step of calculating a continuous operation amount by adding the calculation results;
A second step of determining an operation amount of the compressor corresponding to the continuous operation amount by referring to a discretization table holding the operation amount of the compressor set discretely;
A control method comprising: 6. The control method according to claim 5, wherein in the first step, a continuous operation amount of the operation amount of the compressor is calculated by PID control, PI control, or I-PD control based on the temperature difference. . In the second step, when the continuous operation amount is smaller than a predetermined threshold, the operation amount of the compressor corresponding to the continuous operation amount is determined by referring to the discretization table, and the continuous operation amount is determined. The control method according to claim 5 or 6, wherein when the operation amount is larger than a predetermined threshold, the continuous operation amount is determined as an operation amount of the compressor.

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