JPH1183115A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably adjust a plurality of controlled variables with small mutual interference by varying robust stabilizing gain and adaptively controlling it based on the values of parameters estimated for meeting the fluctuation of the parameters representing dynamic characteristics. SOLUTION: In this air conditioner, sealed refrigerant is compressed and heated by a compressor 20 and flows to an outdoor heat exchanger 21 during a cooling operation. The refrigerant is cooled, liquefied by outdoor air therein and gives heat to air. Further, when the refrigerant passes through an outdoor expansion valve 26, an indoor expansion valves 30l and 30N, its pressure is reduced and the pressure reduced refrigerant enters indoor heat exchangers 28l and 28N. There, the refrigerant takes heat from air. Evaporating refrigerant enters again the compressor and is compressed. On the other hand, during a heating operation, processes opposite to those during the cooling operation are carried out. As described above, a controller controls room temperature and humidity respectively during the heating and cooling operations and also controls the temperature and pressure of the refrigerant of the air conditioner itself as a heat loading device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for heating and cooling air in one or a plurality of utilization units by one or more indoor units connected to one outdoor unit. The present invention relates to an air conditioner that stably controls a refrigerant pressure, a temperature, an air temperature and a humidity of a use unit, and the like by robust control.

[0002]

2. Description of the Related Art An air conditioner itself has a large number of control amounts to be controlled, operation amounts of devices operated to adjust the control amounts, and detection amounts for detecting the operation results.
Moreover, it is an interference system in which the behavior of each manipulated variable affects almost all controlled variables. For example, during the cooling operation, that is, the high-temperature and high-pressure refrigerant discharged by the compressor,
The refrigerant is condensed in the outdoor unit to become a liquid refrigerant, and this liquid refrigerant is decompressed and expanded by the expansion valve, evaporates in the indoor unit to become a gas refrigerant, and this gas refrigerant returns to the compressor to form a refrigeration cycle in which the refrigerant is sucked. In this case, when the compressor drive frequency, which is an operation amount, is increased, the refrigerant discharge temperature, the refrigerant discharge pressure, and the outdoor heat exchanger condensation temperature increase, and the indoor heat exchanger evaporation temperature and the refrigerant suction pressure decrease. In order to reduce the refrigerant discharge pressure as a control amount, if the outdoor fan rotation speed is increased as an operation amount,
The refrigerant discharge temperature may decrease, and the refrigerant evaporation temperature and the refrigerant suction pressure may also decrease. Therefore, if the opening degree of the expansion valve is reduced as the operation amount in order to increase the refrigerant discharge temperature as the control amount, the refrigerant suction pressure may be further reduced. Furthermore, because the cooling capacity, which is the amount of heat per unit time that the indoor unit of the air conditioner gives to the user unit room, changes, the indoor air temperature and indoor air humidity change, and the power of the indoor fan changes. Even conceivable. It is no exaggeration to say that such interference exists between all control amounts and operation amounts.

Therefore, the control method of the conventional control device is designed as follows. For example, two of the refrigerant discharge superheat degree (= the difference between the refrigerant discharge temperature and the saturation temperature) and the indoor air temperature are selected as the control amounts, and the operation amount is any one of the outdoor expansion valve and the indoor expansion valve. And the compressor drive frequency are selected. Basically, it is assumed that the expansion valve controls the refrigerant discharge superheat degree and the compressor drive frequency controls the indoor air temperature. However, actually, there is a change in the indoor air temperature with respect to the operation of the expansion valve, and there is a change in the refrigerant discharge superheat degree with respect to the compressor drive frequency. Therefore, the magnitude of each interference is calculated in advance, and control is performed in consideration of the interference, thereby achieving non-interference control.

A conventional known example of such an air conditioner control device is described in Japanese Patent Application Laid-Open No. 63-29155.

[0005] However, in an air conditioner in which a number of indoor units are connected to one outdoor unit, the number of control amounts and operation amounts is too large to perform non-interference control, and non-interference is performed. There was a problem that it was virtually impossible.

[0006]

The decoupling performed by the conventional air conditioner is very difficult in a multi-input multi-output system having a large number of operation amounts and a large number of control amounts.
We have to change our approach to decoupling.

In a control system in which one operation amount is assigned to one control amount, the operation of the other operation amounts is a disturbance. As described above, when the expansion valve is assigned to control the discharge temperature, the discharge temperature rises sharply as the compressor frequency increases, so the compressor frequency is a disturbance for this combination. Therefore, there is an idea that the sensitivity of the control amount to the disturbance should be reduced. That is, decoupling and disturbance suppression can be discussed from the same viewpoint. Further, there are many other possible disturbances, such as a change in outdoor airflow, a stop operation of the operating indoor unit, an operation of stopping the indoor unit, and a change in the target value of the control amount. For example, a change in the target value of the control amount causes the control amount, which is currently following the target value, to become a value deviated from the target value at the next moment due to the change. This is one of the disturbances affecting the control amount.
As described above, it is obvious that the disturbance suppression technique is very important from the fact that there are many disturbances in combination with decoupling.

However, in the actual control problem, there is a problem of dynamic characteristic fluctuation of a controlled object. In the conventional control system, control design at a certain rated point is performed,
The control performance was not actively compensated for the condition deviated from the rated point. In other words, in the conventional control design, even under the conditions other than the rated point, even if the performance is reasonably satisfied, it is an unsatisfactory result. However, in an actual air conditioner, the outdoor air temperature, the indoor air temperature, the operating indoor unit total capacity, the operating indoor unit total number, the pipe length between the outdoor unit indoor units, the pipe diameter, the height difference between the outdoor unit indoor units, It is well known that the dynamic characteristics of a controlled object fluctuate depending on conditions such as the amount of charged refrigerant and the type of charged refrigerant. For example, when the pipe length is long, the rise of the refrigerant discharge pressure is delayed and the attained value is reduced even at the same compressor drive frequency. At the same time, the ultimate value of the refrigerant suction pressure tends to decrease. This can be said that when the dynamic characteristics of the controlled object are represented by a differential equation or a transfer function, the derivative, which is a parameter thereof, is changing. Therefore, it is necessary to somehow compensate for the parameter variation of the control target.

In addition, a mathematical model for control design is
For example, even if the order of the differential equation, called the order, or the multiplier of the transfer function is constructed as a first-order or second-order using a differential equation or a transfer function, the actual control target has a fifth-order or sixth-order high order. The following terms may be present: Generally, the first order and second order are called low order, and the fifth order and sixth order are called high order. This is a relative wording, with no strict division.
An example in which this higher-order term exists is the refrigerant discharge temperature in FIG. The temperature curve 51 is a calculation based on a primary model, and the temperature curve 52 is a calculation based on a model to which a higher-order term is added. Both of these figures are simulations calculated by a computer, but the actual refrigerant discharge temperature very often repeats minute fluctuations as time passes, as shown by 52. This means that the transfer function G (s) of the controlled
In case of 1

[0010]

(Equation 1)

In the case of the temperature curve 52,

[0012]

(Equation 2)

[0013] This is because the simulation was performed so as to be slightly similar to the actual refrigerant discharge temperature. From the above,
It can be said that the actual refrigerant discharge temperature must be represented by a model to which higher-order terms are added as in the above equation. However, such small fluctuations are very difficult to accurately model.

After all, as described above, fluctuations in dynamic characteristics include parameter fluctuations from the rated value due to differences in conditions, and higher-order terms for which accurate modeling is difficult. The former fluctuations are parameter fluctuations, and the latter fluctuations are parameter fluctuations. As we call it higher-order term variation,
The parameter fluctuation is expressed as Δ1 (s), and the higher-order term fluctuation is expressed as Δ2 (s). The second term in Expression (2) is an example of Δ2 (s). Without a control design that compensates for these variations, the original control system is incomplete.

By the way, as can be said from FIG. 4, when viewed from the output of the rated transfer function Pn (s), the fluctuation transfer function Δ1 (s),
The output of Δ2 (s) is considered as an additional disturbance. Therefore, also in this case, the concept of suppressing the disturbance can handle the fluctuation of the control target. That is, disturbance suppression can be an answer to all problems such as decoupling and dynamic characteristic fluctuation of the control target. Robust control can address this problem.

However, the problem here is that in the current robust control, it is necessary to estimate and calculate some of the fluctuations Δ1 (s) and Δ2 (s). For example, in an air conditioner in which a number of indoor units are connected to one outdoor unit, when controlling the refrigerant discharge temperature, a case where all the indoor units are operating and a case where only one indoor unit is operating There is a difference in the dynamic characteristics from the above, and the dynamic characteristics also change due to the indoor / outdoor air temperature, indoor / outdoor unit piping length, indoor / outdoor unit height difference, etc., which must be estimated as a change in the dynamic characteristics. . It is noticed that these have unexpectedly large fluctuations compared to the magnitude of the rated transfer function Pn (s). Therefore, these fluctuations △ 1 (s) and △ 2 (s) are collectively regarded as one fluctuation, and in order to further secure the compensation, the fluctuation is largely estimated in anticipation of safety and robust control is designed. Then, control is performed under any environment, but the control system often has an undesirable control performance such as responsiveness.

Therefore, the parameter variation Δ1 (s) is dealt with by identifying the variation value from the detected value and using a parameter identification method that actively utilizes the remaining value, and the remaining non-interference and high-order term variation Δ2 Regarding (s), it is sufficient to deal with the conventional robust control. A control method that combines this parameter identification method and the conventional robust control,
Here, it is called adaptive robust control. In simple terms, the robust control is a control using a fixed gain calculated with respect to Pn (s) and Δ2 (s), whereas the adaptive robust control uses Pn (s) and Δ1 (s) by fixing parameters. And make Pn (s) and Δ1 (s) variable transfer functions,
This is control for calculating and updating the stabilization gain with respect to n (s), Δ1 (s) and Δ2 (s) every moment.

An object of the present invention is to provide an air using adaptive robust control so that a plurality of control amounts can be stably adjusted with little interference when adjusting control amounts such as refrigerant discharge pressure, temperature, and room temperature of a compressor. To provide a harmony machine.

[0019]

In order to achieve the above object, a first air conditioner of the present invention comprises a plurality of indoor units connected in parallel to one outdoor unit, and is provided in the outdoor unit. In addition, the compressor, the outdoor heat exchanger and the outdoor expansion valve having a variable drive frequency are sequentially arranged, then the indoor expansion valve and the indoor heat exchanger room provided for each indoor unit are sequentially arranged, and the piping is returned so as to return to the compressor. An outdoor fan for blowing air to the outdoor heat exchanger and an indoor fan for blowing air to the indoor heat exchanger are connected to form a forward circulation path enclosing the refrigerant, and a cooling operation is performed when the refrigerant flows along the forward circulation path. Or an air conditioner that performs a heating operation when the refrigerant flows in a reverse direction to the forward circulation path, a detecting means for detecting the total cooling capacity or the total heating capacity of the operating indoor unit, and an operation of operating the compressor drive frequency Means, and the indoor cooling capacity Or when the total heating capacity is controlled as a control amount, changes in the outdoor expansion valve opening, outdoor fan rotation speed, indoor expansion valve opening, indoor fan rotation speed, and outdoor air flow for the operating indoor unit total cooling capacity or total heating capacity Change, disturbance in the operating indoor unit, operation of the stopped indoor unit, operation of the stopped indoor unit, change in the target value of the total cooling capacity or total heating capacity of the operating indoor unit, or the cooling of the operating indoor unit. When the capacity or total heating capacity is represented by a lower-order mathematical model, the actual cooling capacity or total heating capacity of the actual indoor unit of the operating room includes higher-order terms than the mathematical model, and the adverse effects of the higher-order terms are as follows: Performs stabilization using the robust stabilization gain, but further includes outdoor air temperature, indoor air temperature, operating indoor unit total capacity, operating indoor unit total number,
Pipe length, pipe diameter, height difference between outdoor unit and indoor unit, refrigerant charge amount,
When the dynamic characteristics of the operating indoor unit total cooling capacity or total heating capacity with respect to the compressor drive frequency fluctuates due to a difference in these conditions including at least one of the sealed refrigerant types,
In order to cope with the variation of the parameter representing the dynamic characteristic of the driving indoor unit total cooling capacity or total heating capacity, the robust stabilization gain is made variable based on the value of the estimated parameter, and adaptive control is performed. An adaptive robust control device is provided.

Further, the second air conditioner of the present invention has a first air conditioner.
In this air conditioner, the refrigerant suction pressure of the compressor is used instead of the total cooling capacity or total heating capacity of the operating indoor unit as the control amount, and the compressor drive frequency is used as the operation amount as in the first air conditioner. .

Further, the third air conditioner of the present invention has a first air conditioner.
The refrigerant discharge pressure of the compressor is used instead of the total cooling capacity or total heating capacity of the operating indoor unit as the control amount in the air conditioner, and the compressor drive frequency is used as the control amount in the same manner as the first air conditioner. .

A fourth air conditioner according to the present invention comprises a plurality of indoor units connected in parallel to one outdoor unit, and a variable drive frequency compressor, an outdoor heat exchanger and an outdoor unit provided in the outdoor unit. An outdoor expansion valve is sequentially formed, then an indoor expansion valve and an indoor heat exchanger chamber provided in each indoor unit are sequentially formed, and a pipe is connected so as to return to the compressor to form a forward circulation path in which a refrigerant is sealed, An outdoor fan that blows air to the outdoor heat exchanger and an indoor fan that blows air to the indoor heat exchanger perform a cooling operation when the refrigerant flows along the forward circulation path, or the refrigerant flows in a reverse direction to the forward circulation path In an air conditioner that performs heating operation at the time,
When controlling the refrigerant discharge temperature of the compressor as a control amount to be controlled, and performing feedback control using the outdoor expansion valve opening as an operation amount for adjusting the control amount, the compressor drive frequency and the outdoor fan rotation speed for the control amount and Changes in indoor expansion valve opening and indoor fan speed, changes in outdoor airflow, operation indoor unit stop operation,
Stopped indoor unit operation, disturbance including at least one of disturbances such as a change in the target value of the control amount, or
When the control amount is expressed by a low-order mathematical model, the actual control amount includes a higher-order term than the mathematical model, and against the adverse effects of the higher-order term, stabilization is performed using a robust stabilization gain. Perform, but at least one of outdoor air temperature, indoor air temperature, total operating indoor unit capacity, total number of operating indoor units, pipe length, pipe diameter, height difference between outdoor unit indoor units, amount of refrigerant charged, and type of charged refrigerant When the dynamic characteristic of the control variable with respect to the manipulated variable fluctuates due to the difference between these conditions, the above robust based on the value of the estimated parameter is used to cope with the fluctuation of the parameter representing the dynamic characteristic of the control variable. An adaptive robust control device for adaptively controlling the stabilization gain by changing the stabilization gain is provided.

[0023] A fifth air conditioner of the present invention comprises one outdoor unit and one indoor unit connected by piping, and a variable drive frequency compressor, an outdoor heat exchanger and an outdoor unit provided in the outdoor unit. An outdoor expansion valve is sequentially formed, then an indoor expansion valve and an indoor heat exchanger chamber provided in each indoor unit are sequentially formed, and a pipe is connected so as to return to the compressor to form a forward circulation path in which a refrigerant is sealed, An outdoor fan that blows air to the outdoor heat exchanger and an indoor fan that blows air to the indoor heat exchanger perform a cooling operation when the refrigerant flows along the forward circulation path, or the refrigerant flows in a reverse direction to the forward circulation path In the air conditioner performing the heating operation, when performing the feedback control using the compressor drive frequency as the control amount for controlling the indoor air temperature and the operation amount for adjusting the indoor air temperature, the outdoor air temperature with respect to the indoor air temperature is controlled. Expansion valve opening and outdoor fan rotation Among the disturbances, changes in the number and indoor expansion valve opening and indoor fan rotation speed, outdoor air flow changes, indoor heat generation device ON / OFF operation, indoor ventilation device operation stop operation, indoor window opening / closing operation, and indoor air temperature target value change At least one
When the indoor air temperature is expressed by a lower-order mathematical model when the actual indoor air temperature contains higher-order terms than the mathematical model, and the higher-order Performs stabilization using a robust stabilization gain, but further includes outdoor air temperature, indoor air temperature, pipe length,
At least one of pipe diameter, height difference between indoor and outdoor units, amount of filled refrigerant, type of charged refrigerant, ON / OFF state of indoor heat generating equipment, shutdown of indoor ventilation system, open / close state of indoor windows, and difference in thermal load caused by indoor personnel When the dynamic characteristics of the indoor air temperature with respect to the compressor drive frequency fluctuate due to the difference between these conditions, the estimated parameter value is also changed to correspond to the fluctuation of the parameter representing the dynamic characteristic of the indoor air temperature. In addition, an adaptive robust control device that adaptively performs control by changing the robust stabilization gain is provided.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The adaptive robust control device for an air conditioner according to the present invention includes a plurality of use unit indoor air temperatures, a compressor refrigerant discharge pressure, a compressor refrigerant, in order to obtain a set indoor air temperature and humidity environment. Control variables such as suction pressure, compressor refrigerant discharge superheat degree, operating indoor unit total cooling capacity or total heating capacity
The operation amounts such as the drive frequency of the compressor, the opening degree of the outdoor expansion valve, the opening degree of the indoor expansion valve, the number of rotations of the outdoor fan, and the number of rotations of the indoor fan are controlled so as to coincide with the respective determined target values. As a result, the entire air conditioner can be controlled so that it can always be operated in an appropriate operation state, stable and safe operation can be maintained, and cooling or heating capacity according to the increase or decrease of the load can be obtained. A favorable temperature and humidity environment is obtained. The adaptive robust control device according to the present invention is suitable for an air conditioner having a plurality of utilization units, but it is needless to say that the adaptive robust control device is also suitable for an air conditioner having a single utilization unit.

An embodiment of an adaptive robust control device for an air conditioner according to the present invention will be described below with reference to the drawings. FIG.
Is a configuration diagram showing an air conditioner and a control device. The air conditioner has one outdoor unit 19 and a plurality of indoor units 271, 2
An indoor unit 27 having 7N and comprising an outdoor unit 19 and a plurality of units
1, 27N are connected by piping to form a closed circuit, and a refrigerant is sealed in the closed circuit.

In the outdoor unit 19, the outdoor heat exchanger 21 and the outdoor expansion valve 26 are sequentially piped to the variable frequency compressor 20 via the four-way valve 24, and the outdoor fan blows the outdoor heat exchanger 21. 22. In the indoor units 271 and 27N, the indoor heat exchangers 281 and 28N that exchange heat with the indoor air and the indoor expansion valve 3 that adjusts the flow rate of the refrigerant in the indoor heat exchangers 281 and 28N.
01N and 30N sequentially and indoor heat exchanger 2
It has indoor fans 291 and 29N for blowing air to 81 and 28N.

The outdoor unit 19 includes an accumulator 23 and a receiver 25. Then, the gas side and the liquid side of the outdoor unit 19 and the indoor units 271 and 27N are connected to the gas side pipeline 3
1. A closed circuit is formed by connecting the liquid side conduit 32 and the branch pipes 331 and 33N, and a refrigerant is sealed in the closed circuit.
In addition, the indoor units 271 and 27N are respectively disposed in use units 341 and 34N that are rooms or the like to be air-conditioned.

Further, an outdoor air temperature detector 35 for detecting an outdoor air temperature, a refrigerant discharge superheat degree detector 36 comprising a refrigerant discharge temperature detector and a refrigerant superheat degree calculator, a refrigerant suction pressure detection for detecting a refrigerant suction pressure. Compressor 37, a refrigerant discharge pressure detector 38 for detecting refrigerant discharge pressure, a compressor power detector 39 for detecting power consumption of the compressor 20, an inverter compressor frequency operator 40 for operating the frequency of the compressor 20, an outdoor fan 22, an outdoor fan power operation device 41 for operating the air blowing capacity of the outdoor fan 22, an outdoor fan power detector 42 for detecting the power consumption of the outdoor fan 22, an outdoor expansion valve opening operation device 43 for operating the opening of the outdoor expansion valve 26, Utilization unit indoor air temperature detector 4 for detecting the utilization unit indoor air temperature of utilization units 341 and 34N
41, 44N, utilization section blowout air temperature detectors 451, 45N for detecting the temperature of the blown air to the utilization section, indoor side blower capacity controllers 461, 46N, and indoor fan 291 for controlling the blowing capacity of indoor fans 291, 29N. , 29
N fan power detectors 471 and 47 for detecting N power
N, indoor expansion valve opening controllers 481 and 48N for controlling the refrigerant circulation amounts of the indoor expansion valves 301 and 30N, and a remote controller for storing a predetermined temperature and humidity set value or setting a desired temperature and humidity by a user. It has setting devices 491 and 49N.

The adaptive robust control device 50 reads these detection signals, and operates the compressor frequency operating device 40, the outdoor air blowing capacity operating device 41, the outdoor expansion valve opening degree operating device 43, the indoor air blowing capacity operating device 461, 46N, are wired so as to calculate and control the operation amounts of the indoor expansion valve opening degree controllers 481 and 48N. Compressor (variable or fixed drive frequency)
When there are a plurality of compressors, the equivalent sum of the driving frequencies of the operating compressor is defined as the compressor driving frequency.

In the above-described air conditioner, first, the compressor 20 starts up and performs a compression action, whereby the enclosed refrigerant is compressed and overheated, and flows to the outdoor heat exchanger 21 during cooling. Then, it is cooled and liquefied by the outdoor air, and gives heat to the air. Further, an outdoor expansion valve 26 performing an expansion action,
By passing through the indoor expansion valves 301 and 30N, the pressure is reduced and flows into the indoor heat exchangers 281 and 28N. Then, it is heated and evaporated by the indoor air, and the heat is removed from the air. The evaporated refrigerant again flows into the compressor and is compressed, and thereafter, the above operation is repeated. This is a series of behaviors of the refrigerant of the air conditioner during cooling. On the other hand, at the time of heating, the refrigerant compressed and superheated by the compressor 20 flows toward the indoor heat exchangers 281 and 28N. Then, it is cooled and liquefied by room air, and gives heat to the air. Furthermore, by passing through the indoor expansion valves 301 and 30N and the outdoor expansion valve 26 that perform an expansion action, the pressure is reduced, and flows into the outdoor heat exchanger. Then, the air is heated and evaporated by the outdoor air, and the heat is taken from the air. The evaporated refrigerant again flows into the compressor and is compressed, and thereafter, the above operation is repeated. This is a series of behaviors of the refrigerant of the air conditioner during heating. As described above, during cooling and heating, respectively, the control device controls the indoor air temperature and humidity, and the refrigerant temperature of the air conditioner itself, which is a heat load device,
Controls pressure.

The design method and operation of the adaptive robust stabilization gain mounted on the adaptive robust control device of the present air conditioner will now be described. First, the principle of the current robust control will be briefly described. In the above, the robust control has been described from the viewpoint of decoupling, but the original principle is as follows. The key point of robust control is
It is to consider the dynamic characteristic fluctuation of the controlled object and to suppress the disturbance.

The dynamic characteristic variation means that the dynamic characteristic changes. In short, depending on the environmental change and the passage of time,
Whether the amount of change is known or unknown, there are two meanings: a change in dynamic characteristics, and an unexpected behavior such as an unknown minute change as compared with the known model. The former is referred to as parameter variation Δ1 (s) and the latter is referred to as higher-order term variation Δ2 (s), but the current robust control prior to the present invention does not distinguish between the two and treats them as unknown variations.

In classical control typified by PID and modern control typified by optimal control, the mathematical model of the controlled object is fixed, whereas the feature of the robust control is that It means that the model has a margin. In other words, the mathematical expression model of the control target of the conventional control does not change, or it is known how it changes even if it changes, whereas in the robust control, the mathematical expression model of the control target is That is, in addition to the known rated part, the unknown variable part is considered. In the actual operation of the controlled object, it is rare that the behavior of the mathematical model of the controlled object and the behavior of the actual controlled object almost completely match.Therefore, the rated transfer function which can be regarded as a fixed part in the robust control, the error and A mathematical model composed of the sum of the variable transfer functions that can be said to be realistic.

When stabilizing such a controlled object, stabilizing a rated portion that defines a basic motion is, of course, similar to conventional control, but a portion including a fluctuation transfer function. It is also important to stabilize.
Stabilizing both the rated model and the actual model with fluctuations is called robust stabilization, and the feedback gain used at that time is called robust stabilization gain.

Another point of the robust control is disturbance suppression. Control function transfer function Gwz for disturbance
If (s) is defined and a feedback gain is obtained so as to make the transfer function Gwz (s) as small as possible, the control system using the feedback gain controls the control amount in response to disturbance. It can be said that it is a robust control system that does not disturb.

However, as can be seen from FIG. 4, considering the rated transfer function Pn (s) as a center, the variable transfer functions △ 1 (s), △ 2
Neither the output of (s) nor the disturbance W (s) can be distinguished.
That is, the disturbance due to the disturbance and the disturbance due to the fluctuation of the dynamic characteristic are exactly the same operation. Therefore, since the disturbance and the dynamic characteristic fluctuation originally have the same action, the transfer function G (s) of the control amount with respect to the dynamic characteristic fluctuation is defined, and the G (s) is made as small as possible. If a suitable feedback gain is obtained and control is performed using the feedback gain, a robust control system that is not easily affected by fluctuations in dynamic characteristics can be designed. This is the basic principle of robust control.

The feedback gain is proportional, integral, and integral with respect to (the deviation of) the control amount as in PID control.
It is not fixed as a differential action and takes various forms.
For example, the feedback gain K (s)

[0038]

(Equation 3)

When the operation amount u (s) is feedback u (s) = K (s) y (s) of the detection amount y (s), the operation amount u (s) becomes

[0040]

(Equation 4)

This is an operation having the dynamics described above. The feedback gain K (s) can be said to be a feedback transfer function rather than a mere feedback coefficient. The above is the outline of robust control.

By applying the above principle, as shown in FIG. 1, for example, as shown in FIG. 1, a general method for assuring robust stability against a high-order term variation Δ2 (s) for an outdoor expansion valve of an air conditioner during heating. Suppose that you design a robust control. here,
The control amount is the refrigerant discharge temperature Td (t) or the refrigerant discharge superheat degree T
dSH (t), and the operation amount is the outdoor expansion valve opening degree εo (t).
TdSH indicates how much the refrigerant is heated by the saturation temperature, and is a function of Td and the discharge pressure Pd. Therefore, the TdSH control is based on Td, in which the target value of Td is determined by Pd.
Since the control results, the Td control and the TdSH control can be said to be substantially the same. Here, for simplicity, it is assumed that the refrigerant discharge temperature target value 16 in FIG. 1 is constant. And the dynamic characteristics of the refrigerant discharge temperature

[0043]

(Equation 5)

It can be written that t represents time, and the parameters here are coefficients Ao and Bo of the differential equation. The parameters Ao and Bo in the above equation are the behavior 51 shown in FIG.
In the example, the rising speed and the arrival point are determined. The behavior of the actual air conditioner refrigerant discharge temperature Td (t) is as follows: outdoor air temperature, indoor air temperature, operating indoor unit total capacity, operating indoor unit total number, pipe length, pipe diameter, outdoor unit indoor unit height difference, The parameters Ao and Bo can be said to fluctuate according to the above-mentioned various conditions because they vary according to various conditions such as the amount of the charged refrigerant, the type of the charged refrigerant, the compressor drive frequency, the outdoor fan speed, and the indoor fan speed. In addition, the actual refrigerant discharge temperature of the air conditioner is the above equation (1.1), or
It cannot be represented by a smooth first-order differential equation as shown by 51 in FIG. 3, and as shown in the behavior simulation of Td (t) of 52 shown in FIG.
Includes uncertain higher-order term variation Δ2 (s) of the 6th floor.

Now, the values of the parameters Ao and Bo under certain conditions are considered as the rated values of the parameters. Next, the equation (1.1) is rewritten into a transfer function expression of Td (t) and εo (t). When this is shown in the figure, as shown in FIG. 4, the rated transfer function Pn (s) including the parameters Ao and Bo, the parameter change transfer function Δ1 (s), which is the parameter change, and the higher order change transfer function Δ2 (s) Can be expressed in the form of the sum of Therefore,
The actual transfer function of the refrigerant discharge temperature of the air conditioner and the opening degree of the outdoor expansion valve is expressed as P (s) = Pn (s) + Δ1 (s) + Δ2 (s) as shown in Expression (2). It can be written as (2). s is a Laplace operator.
However, the fluctuations Δ1 (s) and Δ2 (s) themselves are stable and Δ2 (s)
Is suppressed by the size of the known scalar function Wa (s), and its maximum singular value is represented by σ. As shown in Expression (3), σ {Δ ₂ (jω)} ≦ | W _a ( jω) |, (0 ≦ ω <∞) (3) This is a function expressing how the higher-order term variation Δ2 (s) depends on the frequency. From here on, instead of considering the unknown variation Δ2 (s), the known Wa (s)
think of.

Thus, a control system that is stable even when the higher-order term variation Δ2 (s) is added is constructed. Rated transfer function Pn
The fact that both the output of (s) and the output of the actual transfer function P (s) are stable is called robust stability.

FIG. 5 shows a diagram in which the higher order page Δ2 (s) (only) is added to the rated transfer function Pn (s). Parameter variation Δ1 (s)
Do not think now. FIG. 5 can be equivalently expressed as shown in FIG. When the small gain theorem that guarantees the stability of the closed loop is applied to FIG. 6,-{1 + K (s) Pn (s)} ~ ¹
Is stable and as shown in equation (4.1)

[0048]

(Equation 6)

It is necessary and sufficient that However, since the higher-order page Δ2 (s) is unknown (it is a feature of robust control that it is processed as unknown), Δ2 (s) cannot be calculated.
Using Wa (s), another source of (s), as shown in equation (4.2)

[0050]

(Equation 7)

Is a necessary and sufficient condition for stability. symbol‖
・ ‖ _∞ is H _∞ norm (infinity norm), and its definition is

[0052]

(Equation 8)

And, as shown in equation (5.2), σ
Represents the maximum singular value of X (s), and X * (s) represents the conjugate transpose of a complex matrix (vector). As a result, when Expression (4) is satisfied, FIG. 5 becomes equivalently stable, that is, the “closed loop to which Δ2 (s) is added” becomes stable. This is a robust stability condition. Basically, the robust control is based on the robust feedback gain K (s) satisfying the equation (4.2).
Is to seek.

In addition, the response of the control deviation 17 in FIG. 1 is considered. The robust control system designed without considering the response of the control deviation 17 is certainly robust against disturbance in some cases, but the response of the control deviation 17 is poor, and the control amount deviated from the target value due to the disturbance is: Target value 16 promptly
Do not settle. Even when a disturbance occurs and is added and the control amount deviates from the target value, a control system that is robustly stable and quickly converges a control deviation simultaneously satisfies conflicting requirements. However, the control deviation is important in the low frequency band, and the uncertain high-order term fluctuation Δ2 (s) is large in the high frequency band.
If a design is performed in consideration of frequency shaping that places importance on the high-frequency band with respect to higher-order fluctuations, a control design that has high robustness and can quickly settle a control deviation is possible.

FIG. 7 is a schematic diagram of the addition of the higher-order disturbance and the frequency shaping. Now, the control amount is z (s), the detection amount is y (s), the operation amount is u (s), the state amount having dynamic characteristics is x (s),
Disturbance is newly defined as w (s), and each is expressed by differential equation expression

[0056]

(Equation 9)

Are expressed as follows. In FIG.
The specific element of (6.1)-(8.1) is

[0058]

(Equation 10)

It is assumed that this is expressed by the following equation (6.2)-(8.2).

If each variable is associated with the actual state quantity of the air conditioner, xo (t) is the rated component of the refrigerant discharge temperature Td (t), and xs (t) improves the response to disturbance input. A variable expressing the frequency weight Ws (s) considered as a dynamic characteristic, xa (t) is an estimated value Wa in the frequency domain of a higher-order term variation Δ2 (s) of Td (t) of an actual air conditioner. (s) is a variable expressing the dynamic characteristic in the time domain. u (t) is the outdoor expansion valve opening εo (t), w (t) is the output of the fluctuation transfer function, Td (t)
It is also possible to treat a plurality of elements as a vector by using the fluctuation component of as a disturbance input as a variable, and then simultaneously treat disturbance such as an outdoor airflow change. z1 (t) is the frequency weight W
A control quantity based on the dynamic characteristic state quantity xs (s) of s (s), also z
2 (t) is Td output from the estimated value Wa (s) of the fluctuation transfer function.
This is a control amount based on the dynamic characteristic state quantity xa (s) corresponding to the variation of (t). In this example, there is no problem even if it is the same as xs (t) and xa (t), respectively. y (t) is Td (t) itself if the refrigerant discharge temperature can be directly sensed.

Now, it is assumed that the actual behavior of the refrigerant discharge temperature of the air conditioner has been obtained through preliminary experiments and the like. From the data, the data of the reference condition is used as the behavior of the rated point and applied to the primary and secondary equations, and the above equation (6.
2) Determine Ao, Bo, and Co in (8.2) as rated parameters. Next, the magnitude and frequency characteristic of the higher-order term fluctuation Δ2 (s) are identified by various experimental data, and the result is defined as fluctuation information Wa (s). (8.
Determine Aa, Ba, Ca and Da in 2). Also, frequency adjustment factors As, Bs, Cs,
Determine Ds.

With the parameters determined by the above operations, both the rated state quantity xo (t) and the state quantity xo (t) + xa (t) to which the higher-order term fluctuation is added are stabilized, and the control deviation 17 Robust stabilization gain K (s) to settle deviation quickly
Is a frequency expression

[0063]

[Equation 11]

Is obtained from the equations (9), (10) and (11). † represents a pseudo inverse matrix, ⊥ represents an orthonormal component, and 'represents transposition. Matrices A, B1, B2, etc. are (6.1)-(8.1)
Both (6.2)-(8.2) correspond. This gain
By using K (s) to perform feedback u (s) = K (s) y (s)... (12) of the detection amount y (s) as shown in Expression (12), the result is shown in FIG. Higher-order term variation Δ2
Even when (s) exists, the refrigerant discharge temperature can always be stabilized. In addition, it is possible to supply an air conditioner that controls with a quick response to changes in the target value 16 of the refrigerant discharge temperature. This is the robust control.

The above-described variation handling does not yet deal with the parameter variation Δ1 (s). The parameter variation Δ1 (s) is separated from the higher-order term variation Δ2 (s) as described above.
This is because, if (s) = Δ1 (s) + Δ2 (s) is collectively handled by the robust control design method, the fluctuation Δ (s) becomes too large.
If this is left as it is, the feedback coefficient K (s) that must correspond to an extremely wide range of transfer functions must be obtained. However, a control system that is too poor in control performance such as responsiveness is designed. For example, when the outdoor expansion valve controls the refrigerant discharge temperature, the compressor drive frequency rises and changes as a disturbance, and even if the refrigerant discharge temperature rises from a target value, the refrigerant discharge temperature does not immediately decrease, and the target value The temperature may exceed the upper limit allowable temperature range of the compressor before the temperature lowering control is performed.

Therefore, the concept of the parameter identification method is used together. A parameter identification method often used for adaptive control is to calculate a parameter value of a dynamic characteristic expression of a controlled object, such as Ao and Bo in Equation (1.1), when the controlled object is operated and operated, and a detection amount and a reference value. This is a method of estimating by comparing with a mathematical model. There is no unknown higher-order term variation that is a model error, the order and configuration of the model formula are almost complete, and only when the parameter value varies, the feature of the control target is clearly recognized. So,
Adaptive control for identifying the value of the parameter to be controlled from time to time and calculating the optimal control gain online based on the value can be performed. However, as described above, if a model error such as a higher-order term variation that is higher than the mathematical model exists in the actual control target, the accuracy of the parameter value by the parameter identification method deteriorates, so that appropriate control cannot be performed. That is, the adaptive control using the parameter identification method is vulnerable to a change due to a model error.

Further, as described above, one control amount-
Disturbances such as interference operation of other manipulated variables with respect to the combination of manipulated variables, outdoor air flow change, operation indoor unit stop operation, stop indoor unit operation operation, and target value change of control amount exist, but adaptive control using parameter identification Then, the concept of suppressing disturbance is not as thorough as robust control. Therefore, the decoupling is slightly weakened. This is represented as a table as follows.

[0068]

[Table 1]

Therefore, the concept of the robust control and the concept of the adaptive control using the parameter identification method are used together to maximize the advantages of both. As described above, in a situation where the dynamic characteristic parameters of the controlled object fluctuate greatly, as in the example of indoor unit all-room operation and single-unit operation, Pn (s) + Δ1 (s) is estimated by parameter identification. And the higher-order term variation Δ2 which is the model error contained in the actual control target.
For problems where parameter identification is not good, such as stability compensation for (s) and decoupling in a multi-input multi-output system, the concept of robust stabilization is used, and finally the transfer function Pn
Stabilization is performed on (s) + Δ1 (s) + Δ2 (s).

The control algorithm will be described below.
The formulas are described in a time domain expression. First, the air conditioner to be controlled is started and operated. As an example, it is assumed that the operation is performed in the indoor unit all-room operation. At that time, the control is started using the pre-stored rated parameters Ao, Bo and the like to be controlled. At the same time, parameter identification is performed using the detected amount, and the current value of the parameter to be controlled is estimated in real time. The estimation method is performed by the following calculation. Equation (1.2) obtained by transforming equation (1.1) into a discrete form by the model

[0071]

(Equation 12)

In this case, the estimated vector θ (k) and the detection vector q (k) are expressed as in Expression (13).

[0073]

(Equation 13)

Is defined as Here, k is a time step when detection is performed discretely, and Aodest (k), Bodes
t (k) is the estimated value of Aod and Bod in equation (1.2). Since both are scalar between the discrete parameters Aod and Bod and the continuous parameters Ao and Bo, as shown in equation (14)

[0075]

[Equation 14]

It is assumed that the following relationship exists. Δt is a sampling time. At this time, J in Expression (15)

[0077]

(Equation 15)

In order to minimize the following equation (16),

[0079]

(Equation 16)

In the form of the sequential calculation, it is obtained every moment. From this, the estimated values of Aod and Bod during the indoor unit all-room operation can be calculated, and conversely, the continuous type parameters Ao and Bo can be calculated by the above equation (14). This is the rated transfer function Pn
(s) and the parameter variation Δ1 (s) are clarified. From the obtained parameters, the above equations (9) and (1)
The robust stabilization gain K (s) calculated in (0) and (11) is newly calculated. As a result, control is performed to quickly settle the control deviation without making the refrigerant discharge temperature unstable.

Next, it is assumed that the operation has been changed to the operation of one indoor unit according to a command from the user. At this time, the parameters Aod and Bod representing the dynamic characteristics of the refrigerant discharge temperature change greatly. Therefore, the parameters during operation of one indoor unit are estimated in real time by the above estimation method. Similarly, using the estimated new parameters Aod and Bod, a new robust stabilization gain K (s) is calculated using equations (9), (10), and (1).
The calculation and update are performed in 1) to stabilize the control target and to quickly settle the control deviation.

FIG. 8 is a flowchart showing this. First, the operation of the air conditioner is started (61). Thereafter, in order to operate the outdoor expansion valve, which is the manipulated variable, to the initial value, the initial robust stabilization gain is set in consideration of advance information such as whether the operation is the outdoor all-room operation or the single-unit operation (6).
2). Next, the refrigerant discharge temperature, which is a control amount, is
(63). Further, the outdoor expansion valve is actually operated by the operating device 43 while comparing the detected refrigerant discharge temperature with the target value (64).

Here, detection is continuously performed to detect how the refrigerant discharge temperature has changed (65). Using the initially detected refrigerant discharge temperature, the degree of opening of the outdoor expansion valve, and the changed refrigerant discharge temperature, parameters Aodest and Bodest that represent the relationship between the manipulated variable and the control variable are estimated (66). .

Further, the estimated parameters are converted into Ao and Bo, and the robust stabilization gain K (s) is calculated assuming the estimated values of Ao and Bo (67). At the same time when the gain is calculated, the outdoor expansion valve opening for performing feedback is calculated for the difference between the refrigerant discharge temperature detected at 65 and the target value (68). Then, the opening degree is output to the operating device and operated (69). Thereafter, the operations of (65)-(69) are repeatedly performed until a stop condition is input (70). Finally,
When the stop condition is input, the operation is stopped (71). This is a series of operations.

Explaining with reference to FIG. 1 of the block diagram, the existing robust control has a loop of 11 → 14 → 15 → 16, 17
On the other hand, the adaptive robust control has a parameter identification mechanism, so that the information flow is 18 → 10
And has another loop. This is a variable mechanism of the robust stabilization gain K (s).

As described above, the change in the operating condition in which the parameter greatly changes corresponds to the change Δ (s) in the robust control.
By estimating the parameters of the rated transfer function and adaptively changing the robust stabilization gain by the parameter identification method, it is always stable and comfortable for extremely wide operating conditions. An air conditioner control device that creates a temperature environment can be designed. And a comfortable temperature environment can always be supplied to the user stably.

[0087]

As described above, according to the present invention,
The air conditioner uses the parameter identification method even when the control amount such as the refrigerant discharge temperature and the refrigerant discharge superheat degree has different dynamic characteristics under various conditions such as the pipe length between the outdoor unit and the indoor unit, the height difference, and other various conditions. In the case where a higher-order variation not included in the mathematical model of dynamic characteristics is added, adaptive control is performed, and robust stability against the variation is considered in advance. The control amount can be controlled stably by reducing mutual interference. Further, by stabilizing the refrigeration cycle state of the air conditioner, a more reliable air conditioner can be supplied, and the cooling capacity or heating capacity of the user is less fluctuated and the failure is less. It can create comfortable air conditioning.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a transfer function of an air conditioner according to an embodiment of the present invention, and a diagram illustrating a main part of a control device of the air conditioner.

FIG. 2 is a diagram illustrating a configuration of an air conditioner of the present invention.

FIG. 3 is a diagram simulating the behavior of the refrigerant discharge temperature of an actual air conditioner in a case where there is no higher-order variation and in a certain case.

FIG. 4 When the dynamic characteristics of an actual air conditioner are represented by a transfer function, additional fluctuations are added to the ideal rated transfer function due to disturbance, unknown higher-order fluctuations, parameter fluctuations, and the like. FIG.

FIG. 5 is a diagram showing the transfer function of the actual air conditioner shown in FIG.

FIG. 6 is an equivalent representation of FIG.

FIG. 7 is a model block diagram when a dynamic characteristic of an air conditioner having a fluctuation is specifically structured and a control design having a quick response to a disturbance is performed.

FIG. 8 is a flowchart when executing adaptive robust control.

[Explanation of symbols]

 Reference Signs List 3 Robust computing unit 6 Refrigerant discharge temperature transfer function 9 Parameter identifier 10 Robust stabilization gain signal 11 Outdoor expansion valve opening signal 12 Refrigerant discharge temperature rated output 13 Refrigerant discharge temperature fluctuation output 14 Refrigerant discharge temperature 15 Refrigerant discharge temperature detection signal 16 Refrigerant discharge temperature control target value signal 17 Control deviation signal 18 Estimation parameter signal 19 Outdoor unit 20 Compressor 21 Outdoor heat exchanger 22 Outdoor fan 23 Accumulator 24 Four-way valve 25 Receiver 26 Outdoor expansion valve 271, 27N Indoor unit 281, 28N Indoor heat Exchanger 291, 29N Indoor fan 301, 30N Indoor expansion valve 31 Gas pipe 32 Liquid pipe 331, 33N Branch pipe 341, 34N Utilization section 35 Outdoor air temperature detector 36 Refrigerant discharge superheat degree detector 37 Refrigerant suction pressure detector 38 Refrigerant Discharge pressure detector 39 Compressor power Alarm 40 Inverter compressor operation device 41 Outdoor air blowing capacity operation device 42 Outdoor fan power detector 43 Outdoor expansion valve opening operation device 441, 44N Indoor air temperature detector 451, 45N Blow-out air temperature detector 461, 46N Indoor side Ventilation capacity controller 471, 47N Indoor fan power detector 481, 48N Indoor expansion valve opening controller 491, 49N Remote controller setting unit 50 Adaptive robust control unit 57 Disturbance 58 Fluctuation transfer function model 59 Rated transfer function model 60 Responsive weight model

Continued on the front page (72) Inventor Satoru Yoshida 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Inside Air Conditioning Systems Division, Hitachi, Ltd. (72) Inventor Kenichi Nakamura 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Inside Air Conditioning Systems Division, Hitachi, Ltd.

Claims (5)

[Claims] A plurality of indoor units are connected in parallel to one outdoor unit by piping, and a compressor having a variable drive frequency, an outdoor heat exchanger, and an outdoor expansion valve provided in the outdoor unit are sequentially arranged. The indoor expansion valve and the indoor heat exchanger chamber provided in each indoor unit are sequentially connected to each other, and a pipe is connected to return to the compressor to form a forward circulation path filled with refrigerant, and the outdoor heat exchanger is connected to the outdoor heat exchanger. An outdoor fan that blows air and an indoor fan that blows air to the indoor heat exchanger perform a cooling operation when the refrigerant flows along the forward circulation path, or perform a heating operation when the refrigerant flows in the reverse direction to the forward circulation path. In the air conditioner to be performed, when the feedback control is performed using the compressor drive frequency as the operation amount for controlling the total cooling capacity or total heating capacity of the operating indoor unit and the operation amount for adjusting the control amount, the outdoor amount with respect to the control amount Expansion valve opening and chamber Disturbance including at least one of a disturbance such as a change in a fan rotation speed, an indoor expansion valve opening degree, an indoor fan rotation speed, an outdoor air flow change, an operation indoor unit stop operation, a stop indoor unit operation operation, or a change in a target value of a control amount. When the control amount is expressed by a lower-order mathematical model, the robust control gain is used to stabilize the adverse effects of higher-order terms included in the actual control amount than the mathematical model. However, at least one of the outdoor air temperature, the indoor air temperature, the operating indoor unit total capacity, the operating indoor unit total number, the pipe length, the pipe diameter, the height difference between the outdoor unit indoor units, the refrigerant charging amount, and the charged refrigerant type. When the dynamic characteristic of the control amount with respect to the manipulated variable fluctuates due to the difference in these conditions including one, in order to cope with the fluctuation of the parameter representing the dynamic characteristic of the control amount, based on the value of the estimated parameter, Robust above An air conditioner equipped with an adaptive robust control device that adaptively controls with a variable stabilization gain. 2. A plurality of indoor units are connected in parallel to one outdoor unit by piping, and a compressor having a variable drive frequency, an outdoor heat exchanger, and an outdoor expansion valve provided in the outdoor unit are sequentially arranged. The indoor expansion valve and the indoor heat exchanger chamber provided in each indoor unit are sequentially connected to each other, and a pipe is connected to return to the compressor to form a forward circulation path filled with refrigerant, and the outdoor heat exchanger is connected to the outdoor heat exchanger. An outdoor fan that blows air and an indoor fan that blows air to the indoor heat exchanger perform a cooling operation when the refrigerant flows along the forward circulation path, or perform a heating operation when the refrigerant flows in the reverse direction to the forward circulation path. In the air conditioner to be performed, when the refrigerant suction pressure of the compressor is a control amount to be controlled, and the feedback control is performed using the compressor drive frequency as an operation amount for adjusting the control amount, the outdoor expansion valve opening degree with respect to the control amount is controlled. And outdoor fan speed and room For a disturbance including at least one of disturbances such as a change in an expansion valve opening degree and a rotation number of an indoor fan, a change in an outdoor air flow, a stop operation of a driving indoor unit, a driving operation of a stopped indoor unit, and a change in a target value of a control amount, or When the control amount is represented by a lower-order mathematical model, the actual control amount includes, with respect to the adverse effects of higher-order terms than the mathematical model, stabilization is performed using a robust stabilization gain. In addition, outdoor air temperature, indoor air temperature, operating indoor unit total capacity,
At least one of the total number of operating indoor units, pipe length, pipe diameter, height difference between outdoor units and indoor units, amount of refrigerant charged, and type of refrigerant charged
When the dynamic characteristic of the control amount with respect to the manipulated variable fluctuates due to the difference in these conditions including the one above, in order to respond to the fluctuation of the parameter representing the dynamic characteristic of the control amount, the above An air conditioner equipped with an adaptive robust control device that performs adaptive control with a variable robust stabilization gain. 3. A plurality of indoor units are connected in parallel to one outdoor unit by piping, and a compressor having a variable drive frequency, an outdoor heat exchanger, and an outdoor expansion valve provided in the outdoor unit are sequentially arranged. The indoor expansion valve and the indoor heat exchanger chamber provided in each indoor unit are sequentially connected to each other, and a pipe is connected to return to the compressor to form a forward circulation path filled with refrigerant, and the outdoor heat exchanger is connected to the outdoor heat exchanger. An outdoor fan that blows air and an indoor fan that blows air to the indoor heat exchanger perform a cooling operation when the refrigerant flows along the forward circulation path, or perform a heating operation when the refrigerant flows in the reverse direction to the forward circulation path. When performing feedback control using the compressor drive frequency as an operation amount for controlling the refrigerant discharge pressure of the compressor in the air conditioner to be controlled and controlling the control amount, the outdoor expansion valve opening relative to the control amount And outdoor fan speed and room For a disturbance including at least one of disturbances such as a change in an expansion valve opening degree and a rotation number of an indoor fan, a change in an outdoor air flow, a stop operation of a driving indoor unit, a driving operation of a stopped indoor unit, and a change in a target value of a control amount, or When the control amount is represented by a lower-order mathematical model, the actual control amount includes, with respect to the adverse effects of higher-order terms than the mathematical model, stabilization is performed using a robust stabilization gain. In addition, outdoor air temperature, indoor air temperature, operating indoor unit total capacity,
At least one of the total number of operating indoor units, pipe length, pipe diameter, height difference between outdoor units and indoor units, amount of refrigerant charged, and type of refrigerant charged
When the dynamic characteristic of the control amount with respect to the manipulated variable fluctuates due to the difference in these conditions including the one above, in order to respond to the fluctuation of the parameter representing the dynamic characteristic of the control amount, the above An air conditioner equipped with an adaptive robust control device that performs adaptive control with a variable robust stabilization gain. 4. A plurality of indoor units are connected in parallel to one outdoor unit by piping, and a compressor having a variable drive frequency, an outdoor heat exchanger, and an outdoor expansion valve provided in the outdoor unit are sequentially arranged. The indoor expansion valve and the indoor heat exchanger chamber provided in each indoor unit are sequentially connected to each other, and a pipe is connected to return to the compressor to form a forward circulation path filled with refrigerant, and the outdoor heat exchanger is connected to the outdoor heat exchanger. An outdoor fan that blows air and an indoor fan that blows air to the indoor heat exchanger perform a cooling operation when the refrigerant flows along the forward circulation path, or perform a heating operation when the refrigerant flows in the reverse direction to the forward circulation path. In the air conditioner to be performed, when the feedback control is performed using the outdoor expansion valve opening as an operation amount for controlling the refrigerant discharge temperature of the compressor as a control amount for controlling the control amount, the compressor drive frequency with respect to the control amount is controlled. And outdoor fan speed and room For a disturbance including at least one of disturbances such as a change in an expansion valve opening degree and a rotation number of an indoor fan, a change in an outdoor air flow, a stop operation of a driving indoor unit, a driving operation of a stopped indoor unit, and a change in a target value of a control amount, or When the control amount is represented by a lower-order mathematical model, the actual control amount includes, with respect to the adverse effects of higher-order terms than the mathematical model, stabilization is performed using a robust stabilization gain. In addition, outdoor air temperature, indoor air temperature, operating indoor unit total capacity,
At least one of the total number of operating indoor units, pipe length, pipe diameter, height difference between outdoor units and indoor units, amount of refrigerant charged, and type of refrigerant charged
When the dynamic characteristic of the control amount with respect to the manipulated variable fluctuates due to the difference in these conditions including the one above, in order to respond to the fluctuation of the parameter representing the dynamic characteristic of the control amount, An air conditioner comprising an adaptive robust control device that adaptively controls by making a robust stabilization gain variable. 5. An outdoor unit and an indoor unit are connected by piping, and a compressor having a variable drive frequency, an outdoor heat exchanger, and an outdoor expansion valve provided in the outdoor unit are successively provided. The indoor expansion valve and the indoor heat exchanger chamber provided in each indoor unit are sequentially connected to each other, and a pipe is connected to return to the compressor to form a forward circulation path filled with refrigerant, and the outdoor heat exchanger is connected to the outdoor heat exchanger. An outdoor fan that blows air and an indoor fan that blows air to the indoor heat exchanger perform a cooling operation when the refrigerant flows along the forward circulation path, or perform a heating operation when the refrigerant flows in the reverse direction to the forward circulation path. In the air conditioner to be performed, when the feedback control is performed using the compressor drive frequency as the control amount for controlling the indoor air temperature and the operation amount for adjusting the indoor air temperature, the outdoor expansion valve opening degree with respect to the indoor air temperature or Outdoor fan speed and indoor At least one of disturbances such as a change in the opening degree of the expansion valve and the number of rotations of the indoor fan, a change in the outdoor air flow, an operation for turning on / off the indoor heat generating device, an operation for stopping the operation of the indoor ventilation device, an operation for opening and closing the indoor window, and a change in the target value of the indoor air temperature. Robust stabilization against disturbances including, or when the room air temperature is expressed by a lower-order mathematical model, and the adverse effects of higher-order terms than the mathematical model include the actual room air temperature The gain is used for stabilization, but the outdoor air temperature, indoor air temperature, pipe length, pipe diameter, height difference between outdoor and indoor units, refrigerant charge, refrigerant charge, indoor heat generation equipment on / off status, and indoor ventilation Due to the difference in these conditions including at least one of the device operation stop, the indoor window opening / closing state, and the thermal load difference occurring in the indoor personnel,
When the dynamic characteristic of the indoor air temperature with respect to the compressor drive frequency fluctuates, the robust stabilization gain is varied based on the value of the estimated parameter to cope with the fluctuation of the parameter representing the dynamic characteristic of the indoor air temperature. An air conditioner comprising an adaptive robust control device that performs adaptive control.