JP2518273B2 - Air conditioning control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for an air conditioner, to which modern control theory is applied in order to stably control the air conditioner.

[Conventional technology]

Conventionally, for example, in a vehicle air conditioner, a refrigerant compression refrigeration cycle has been used. As the control of this refrigeration cycle, it is general to intermittently transmit the power to the refrigerant compressor according to the cooling load. Even with such intermittent control of the compressor, power loss is large and air-conditioning feeling is bad, so that many variable displacement refrigerant compressors have been proposed.

Further, in an expansion valve that adjusts the refrigerant flowing into a cooler (evaporator), it has been proposed to adjust the opening of the expansion valve by an electric drive mechanism. With these devices, the capacity of the compressor and the opening degree of the expansion valve can be adjusted according to the cooling load, the power loss is greatly reduced, and the air conditioning feeling is also improved.

[Problems to be solved by the invention]

However, even in an air conditioner equipped with a refrigeration cycle capacity adjusting device typified by such a variable capacity refrigerant compressor, power loss, air conditioning feeling, etc. are not achievable with conventional control based on proportional, integral, differential or a combination thereof. It could not be said that the sufficient effect was obtained.

Therefore, the present invention applies modern control theory to the design of a control device for an air conditioner, and configures this control device as an optimum integral regulator to treat the air conditioner as a multi-input multi-output system. The control is performed in consideration of the interference between the input and output, and the purpose is to optimize the air conditioning system control and further improve the air conditioning feeling.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a cooling system for cooling the air, which is provided in a ventilation path having a downstream side communicating with the room as shown in FIG. 1 and evaporates a refrigerant circulating in a refrigeration cycle. And a cooling capacity adjusting device that is provided in the refrigeration cycle and that adjusts the cooling capacity of the cooler, a capacity detecting unit that detects the cooling capacity of the cooler, and a cooling path of the ventilation path provided downstream of the cooler. The temperature control means for heating the air and controlling the temperature of the blown air, the room temperature detection means for detecting the air temperature in the room, the capacity setting means for setting the target value of the cooling capacity, and the air in the room A room temperature setting means for setting a temperature target value; a capacity deviation accumulating means for accumulating a deviation between a detection capacity detected by the capacity detecting means and a target capacity set by the capacity setting means; A room temperature deviation accumulating means for accumulating a deviation between a detected room temperature detected by the stage and a target room temperature set by the room temperature setting means; and a control input of at least an adjusting amount of the cooling capacity adjusting device and an adjusting amount of the temperature adjusting means. And, at least the cooling capacity, and a dynamic model of the system that uses the indoor air temperature as a control output, feed bark at least the detection capacity, the detected room temperature, the capacity deviation accumulated value, and the room temperature deviation accumulated value. An air conditioning control device is provided which stores a feedback gain as an additional integral type optimum regulator to be controlled, and feedback control amount calculation means for calculating a command value of the control input based on the feedback gain.

[Action]

 The operation of the air conditioning control device of the present invention will be described.

The air-conditioning control device of the present invention is configured as an additional integral type optimum regulator as shown in FIG. 1, and detects and feeds back the cooling capacity and the room temperature as the control output of the air-conditioning device to obtain a dynamic feedback of the air-conditioning device. A feedback gain predetermined based on the model is used to output a command for the adjustment amount of the cooling capacity adjusting device and the adjustment amount of the temperature adjusting means as control inputs.

This feedback gain treats the air conditioner as a multi-input multi-output system as a dynamic model considering mutual interference of each input and output based on the modern control theory, and this dynamic model is calculated by the above-mentioned additional integral type optimal regulator. It is decided through many simulations and the like so that the optimum state is controlled.

Here, in the present invention, the cooling capacity in the cooler of the refrigeration cycle that constitutes the air conditioner is treated as the control output of the air conditioner together with the room temperature that is the output of the air conditioner.

As a result, the indoor temperature, which is the output of the air conditioner, is controlled to a state that is considered stable and optimal, and the cooling capacity of the refrigeration cycle that configures the air conditioner is controlled to be stable and optimal.

〔The invention's effect〕

As described above, according to the configuration and operation of the present invention, it is possible to stably control the indoor temperature,
It is possible to stably control the cooling capacity of the refrigeration cycle for controlling the indoor temperature to a state considered to be optimum.

 As a result, good air conditioning can be performed.

〔Example〕

 Examples to which the present invention is applied will be described below.

First, the configuration of this embodiment will be described with reference to the drawings.
In this embodiment, the present invention is applied to a controller for a vapor compression refrigeration cycle used in a vehicle air conditioner.

FIG. 2 shows the configuration of the vehicle air conditioning control device. A vehicle air conditioner (hereinafter referred to as an air conditioner) 2 that performs air conditioning of a vehicle interior 1 has the following configuration.

Reference numeral 3 is a ventilation duct of the vehicle air conditioner 2, 4 is an inside air inlet communicating with the vehicle compartment 1, and 5 is an outside air inlet communicating with the outside of the vehicle compartment. Reference numeral 6 denotes an inside / outside air switching damper for selecting either the inside air intake 4 or the outside air intake 5, which is in the inside air mode at the position shown and in the outside air mode at the position shown by the broken line. Reference numeral 7 denotes a blower that sucks the outside air or the inside air into the duct 3 and blows the air toward the vehicle compartment 1, and includes a blower motor 7a and a blower fan 7b.

8 is a refrigeration cycle, 8a is an evaporator, 8b is a variable displacement compressor, 8c is a condenser, 8d is a receiver, 8e is a variable opening expansion valve, and 8f is a magnet clutch. The refrigerant circulates in the refrigeration cycle 8 to exchange heat. The high-temperature high-pressure refrigerant gas compressed by the variable capacity compressor 8b is cooled and liquefied by the condenser 8c, and gas-liquid separated by the receiver 8d,
It is atomized by the variable opening expansion valve 8e, vaporized by the evaporator 8a, and takes heat of the evaporator 8a. The gaseous refrigerant vaporized by the evaporator 8a is again sucked into the variable capacity compressor 8b, the heat is removed from the air on the surface of the evaporator 8a, and the heat is discharged to the air on the surface of the condenser 8c, thus repeating the refrigeration cycle.

A heating device 9 is composed of a heater core 9a, a hot water source 9b, and a water valve 9c. The hot water supplied from the hot water source 9b heats the air passing through the heater core 9a. The hot water source 9b is an engine that serves as a power source for the vehicle, and uses its cooling water as hot water. Reference numeral 10 denotes an air mix damper, which controls the temperature of the air blown into the passenger compartment downstream of the heater core 9a by adjusting the amount of air passing through the heater core 9a among the air cooled by the evaporator 8a. .

Reference numeral 11 denotes a control device including a microcomputer, which includes a CPU, a ROM, a RAM, an I / O port, which is a general configuration, and a bus which electrically connects these. This controller 11
Receives signals from various sensors and input devices described below and outputs drive signals to various actuators.

12 is an outside air temperature sensor provided outside the vehicle compartment, 13 is an after-evaporation sensor that detects the air temperature behind the evaporator, 14 is an inside air temperature sensor provided in the vehicle compartment, 15 is a solar radiation sensor provided in the vehicle compartment, and 16 is a hot water source. Is a water temperature sensor, 17 is a refrigerant temperature sensor that detects the refrigerant temperature at the inlet of the evaporator 8a, and 18 is a refrigerant temperature sensor that detects the refrigerant temperature at the outlet of the evaporator 8a. 19 is a rotation speed sensor for detecting the engine rotation speed. Reference numeral 17 is a temperature setter for setting a target temperature in the passenger compartment, and 21 is operation and stop of the air conditioner 2, air volume,
Various switches that specify modes such as inside and outside air.

Reference numeral 22 is an inside / outside air switching servomotor for driving the inside / outside air switching damper 6, and 23 is a speed control circuit for adjusting the rotation speed of the blower motor 7a of the blower 7. 24 is a variable displacement actuator that operates the variable displacement mechanism of the variable displacement compressor 8b, 25 is an expansion valve actuator (such as a motor or solenoid) that operates the variable opening expansion valve 8e, and 26 is an air mix that drives the air mix damper 10. Servo motor, 27 is a water valve 9
It is a water valve servo motor that operates the.

Next, the configuration of the control device 11 for controlling the air conditioner, which is the gist of the present invention, will be described in more detail.

FIG. 3 is a block diagram showing the configuration of the control system.

In this embodiment, the control system is configured as an additional integral optimal regulator for controlling the air temperature T _E and the superheat SH immediately evaporator 8a of the room temperature T _R with the refrigerating cycle 8 which is temperature control by the air conditioner.

Additional integral optimal regulator as shown in FIG. 3, the target room temperature T _R ^*, the target post-evaporator temperature T _E ^*, the target superheat SH ^* is actuated given (P1, P2, P3). Then, the operating range of the non-linear refrigeration cycle is divided into several ranges that can be considered to be valid for the linear approximation, and the steady point T _R a, T _E a, SHa, DOa, Va, EOa within this range is divided. Perturbations δT _R , δT
It is configured to handle each controlled variable as _E , δSH, δDO, δV, δEO (P4, P5). This linear approximation is modeling of a dynamic model, and a dynamic model for each range is assumed.

In addition, the addition integral type optimal regulator Is estimated based on the above perturbation (P6), and the cumulative Z of the deviation S between the target and the actual is calculated (P7, P8, P9, P10, P11, P
12), State variable quantity according to cumulative value Z To a predetermined optimum feedback gain Determine the feedback control amount by multiplying by (P13). Then, a control amount obtained by adding the value of the steady point to this perturbation component δ is output (P5).

Further, the feedback gain, the parameter of the observer, each steady point and (dynamic model) are switched based on the operating state of the air conditioner 2 (P14).

Next, the design procedure of this embodiment will be briefly described. It should be noted that this design procedure shows one method based on the modern control theory, and various methods other than the method described below are known. As for these modern control theories, for example, Katsuhisa Furuta “Linear System Control Theory” (Showa era)
51) Shokoido, Katsuhisa Furuta and others "Mechanical system control" (1984) Ohmsha, Katsuhisa Furuta and Akira Sano "Basic system theory" (1978) Corona, etc. And so on.

In this embodiment, the behavior of the system of the air conditioner 2 is calculated using a state equation and an output equation, As. In the equations (1) and (2), Is the state variable amount of the air conditioner 2, Represents the air mix damper opening DO, the compressor capacity V, the expansion valve opening EO as the control input of the air conditioner 2, Indicates the room temperature T _R , the post-evaporation temperature T _E , and the superheat SH as the control output of the air conditioner 2, and the subscript k indicates the number of times of sampling. FIG. 4 shows the transfer function G ₁ (z), G of the system of the air conditioner 2 operating as a system of 3 inputs and 3 outputs.
₂ (z), G ₃ (z), G ₄ (z), G ₅ (z), G ₆ (z), G
FIG. ₇ is a block diagram expressed by ₇ (z). Incidentally, z
Represents the z-transform of the sampled value of the input / output signal, and G (z) has an appropriate order.

When it is extremely difficult to determine a physical model like the air conditioner 2 of the present embodiment, the transfer function G (z) is obtained by a kind of simulation called system and identification.
Can be obtained, but here the identification is performed by the least squares method.

Operate the air conditioner 2 in a predetermined operating state,
Two of V and δEO are set to zero, and the remaining one is added with an appropriate test signal, and δ which is the input and output at that time.
Data of any one of T _R , δT _E , and δSH is sampled N times. This is input data series {u (i)},
Output data series {y (i)} (correct, i = 1,3, ...
N). At this time, each input / output can be regarded as a system with one input and one output. For example, the transfer function G ₁ (z) is G ₁ (z) = B ₁ (z ⁻¹ ) / A ₁ (z ^{− 1} ) ...... (3) That is, G ₁ (z) = (b ₀ + b ₁ · z ^-1 +… + b _n · z ^-n ) / (1 + a ₁ · z ^-1 + a ₂ · z ^-2 +… ＋ a _n・ z ^-n ) …… (4). Here, z ⁻¹ is a unit transition operator, which means z ⁻¹ · X (k) = X (k−1).

The transfer function G ₁ (z) can be obtained by determining the parameters a _{1 to} a _n and b _{0 to} b _n of the equation (4) from the input / output data series {u (i)} and {y (i)}. . System identification by the least-squares method uses these parameters a _{1 to} a _n and b _{0 to} b _n . Is set to be the minimum. In this example, each parameter was obtained with n =. In this case, the signal flow diagram of the system of each transfer function is as shown in Fig. 5, and [X ₁ (k)] is taken as the state variable, and the state-output equation is X ₁ (k + 1) = z · X ₁ (k) = expressed as _{-a 1 · X 1 (k)} + b 1 · u (k) ...... (6) y (k) = X 1 (k) ...... (7). Therefore, the system parameters when viewed as a system with one input and one output Are each Becomes

In this way, the system parameters of each transfer function are obtained, and from this, the system parameters of an air conditioner with three inputs and three outputs. Is required. This dynamic model is defined in such a manner that when the air conditioner 2 is operated in a predetermined state, a linear approximation holds in the vicinity of this state. Therefore, for multiple steady operating states, each transfer function is
G ₁ (z) to G ₇ (z) are obtained, and from these, the vector in the state equation (1) and the output equation (2) as a system of three inputs and three outputs Is obtained, and the input / output relationship is established during the perturbation δ.

(B) Design of observer Design an observer that estimates the amount of state variables of the system using the above-mentioned degree of degree.

 In this embodiment, it is designed as the same-dimensional observer.

The same-dimensional observer has the configuration shown in FIG. 6, and as shown in the figure, the estimated value of the state variable. As the feedback gain, Becomes here Choose If the absolute values of the unique rights of the matrix are all less than 1, It has been proved that Therefore, That way, and Then the observer Becomes

Parameters Is obtained for each model obtained for a steady operating state.

(C) System expansion Since the control target of this embodiment is a servo system in which the target values T _R ^* , T _E ^* , SH ^* change, the system is expanded using cumulative values. That is, the state variable amount estimated by the observer Including this and And

That is, Becomes

(D) Optimal feed bark gain The system of the system expanded in (c) above is expressed as follows.

Where the state variable quantity Is the 7th order, Is.

At this time, the optimum control input that minimizes the following evaluation function J,
That is, operating conditions Is to solve the control problem as the optimum integral regulator for the air conditioner 2.

Incidentally, here Is the weight parameter matrix, and k is the number of samplings when the control start time is 0. The right side of equation (15) is Is a so-called quadratic form expression in which is a diagonal matrix.

As a result, optimum control input Is Becomes

here, Is And Is a positive definite solution of the following matrix Riccati equation.

Here, the meaning of the evaluation function J in the equation (15) is the amount of operating conditions as the control input to the air conditioner. Of the operating state as a control output while limiting the movement of the It is intended to minimize the deviation of. Various operating conditions The weighting of the constraints for is the weight parameter matrix It can be changed by the value of. Therefore, the dynamic model of the air conditioner 2 which has already been obtained, that is, the matrix Using an arbitrary weight parameter matrix And solve equation (18) And obtain the optimum feedback gain using equation (17). Can be requested. Therefore, this optimal feedback gain Control input variables of the air conditioner 2 using To Can be obtained as

This feedback gain Is determined for each model.

Above, the configuration of the optimum integral regulator (Fig. 3)
The modeling of the control system, the design of the observer, the expansion of the system, and the setting of the optimum feedback gain have been explained based on the above.
Inside 11, the actual control is performed using only the result.

In addition, the above Is a 7 × 3 matrix, Is a 7 × 3 matrix, and Is obtained as a 3 × 10 matrix.

Next, the operation of the control device 11 for realizing the control system as described above will be described.

FIG. 7, FIG. 8 and FIG. 9 are flowcharts for realizing the above control system.

The control device 11 of this embodiment starts execution of a predetermined program when the car air conditioner 2 is activated.

In this embodiment, the control related to the refrigeration cycle, which has a relatively high response speed, and the control related to the room temperature, which has a relatively slow response speed, are separated, and the control related to the room temperature is performed less frequently than the control related to the refrigeration cycle. Configured to run on.

That is, according to the flowchart shown in FIG. 7, the refrigeration cycle control is executed in the calculation cycle of the loop consisting of step 300, step 400 and step 500, and the room temperature control is executed from step 200, step 300, step 400 and step 600. By the loop, the timer time T becomes the set time T
Every time it becomes s or more, it is executed together with the refrigeration cycle control. As a result, it is possible to stably adjust the opening of the air mix damper 10, which is considered to have the greatest effect on room temperature, which has a slow response speed, and it is possible to reduce energy consumption for operating the actuator. .

The waiting time of step 500 is for adjusting the calculation cycle of both loops described above, and is set so that the sampling cycle is constant.

The flowchart of FIG. 8 shows the part related to the refrigeration cycle control.

First, in step 301, the sample timing k is incremented.

In step 302, the indoor temperature T _R (k) detected by the inside air temperature sensor 14 and the after-evaporation temperature T detected by the after-evaporation sensor 13
Signals of _E (k), a temperature difference (superheat) SH (k) between the refrigerant temperature sensors 17 and 18, a temperature setting device 20, various switches 21, and the like are input.

In step 303, the target indoor temperature T _R ^* (k), the target post-evaporator temperature T _E ^* (k), the target superheat SH ^* (k) is calculated. The target post-evaporator temperature T _E ^* (k) is calculated according to the vehicle interior target temperature, the inside air temperature, the outside air temperature, the cooling water temperature, the necessity of dehumidifying action, and the like. The calculation process of step 303 corresponds to the target setting units P1, P2, P3 in FIG.

In step 304, the deviation ST _R (k), ST _E between the target value calculated in step 303 and the value input in step 302
(K) and SSH (k) are calculated.

The calculation processing in step 304 is performed by the addition units P7 and P in FIG.
It corresponds to 8, P9.

In step 305, the process of accumulating the deviations obtained in step 304 is performed, and the cumulative deviations ZT _R (k), ZT _E (k), ZSH
(K) is calculated.

Incidentally, T in the equation is a sampling period. This step
The arithmetic processing of 305 corresponds to the accumulating units P10, P11, P12 in FIG.

In step 306, when the dynamic model of the air conditioner 2 is constructed based on the various signals input in step 302, the closest state is selected from the steady operating states adopted as the range in which the linear approximation holds, and the Steady state point and feedback gain Select and. This process is performed by the model setting unit P14 in FIG.
Hits.

In step 307, a process of extracting the perturbation component δ from the stationary point is performed.

The calculation process of step 307 corresponds to the perturbation component extraction unit P4 in FIG.

Predetermined in step 308 and selected in step 306 And the perturbation of the control output obtained in the previous step 307 [δT _R (k-1) δT _E (k-1), δSH (k-1)] ^T
And the previously estimated state variable amount And the perturbation component of the control input previously obtained [δDO (j) δ
V (k−1) δEO (k−1)] ^T and the above equation (1
Based on 1), the amount of state variables Is estimated. It should be noted that the perturbation component δDO (j) is the value calculated in the previous step 600.

The calculation process of step 308 corresponds to the state variable amount estimation unit P6 in FIG.

In step 309, the state variable amount obtained in step 308 And the cumulative deviation obtained in step 305 From the above, the perturbation component δV (k) of the compressor capacity and the perturbation component δEO (k) of the expansion valve opening, which are the manipulated variables related to the refrigeration cycle, are calculated from the above equation (19).

The calculation process of step 309 corresponds to a part of the feedback control amount calculation unit P13 of FIG.

In step 310, V (k) and EO are calculated from the perturbations δV (k) and δEO (k) of the compressor capacity obtained in step 309 and the steady point values Va and EOa selected in step 306.
(K) is calculated. The calculation process of step 310 is
It corresponds to a part of the steady value adding unit P5 in FIG.

In step 311, the variable displacement actuator 21 and the expansion valve actuator 25 are controlled so that the compressor capacities V (k) and EO (k) obtained in step 310 are realized.

The flow chart of FIG. 9 shows the part related to room temperature control.

In step 601, the sample timing j is incremented.

In step 602, the state variable amount obtained in step 308 shown in FIG. 8 described above. And the cumulative deviation obtained in step 305 From this, the perturbation component δDO (j) of the air mix damper opening, which is the operation amount related to room temperature, is calculated based on the above equation (19).

The calculation process of step 602 corresponds to a part of the feedback control amount calculation unit P13 of FIG.

In step 603, the perturbation component δ obtained in step 602 is calculated.
DO (j) is calculated from DO (j) and the steady point value DOa selected in step 306.

The calculation process of step 603 is performed by the steady value addition unit P of FIG.
It corresponds to 5.

In step 604, the air mix servomotor 26 is controlled so that the opening degree DO (j) of the air mix damper 10 obtained in step 603 is realized.

By executing the flowcharts of FIG. 7, FIG. 8 and FIG. 9 explained above, the control system shown in FIG. 3 is realized, and the air conditioner 2 is controlled to the optimum condition.

As described above, in this embodiment, the air-conditioning control device is configured as an optimum integral type regulator according to the modern control theory, and the cooling efficiency of the evaporator, which has a great influence on the cooling capacity, as well as the post-evaporator temperature which corresponds to the cooling capacity of the refrigeration cycle. Since the refrigerant superheat (superheat) is also controlled by the addition integral type optimum regulator, stable air conditioning can be performed and power loss in the refrigeration cycle can be reduced.

Further, as shown in the flowchart of FIG. 7, since the control relating to the refrigeration cycle and the room temperature having different responsiveness is divided, it is possible to perform good control with less loss according to each responsiveness. .

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing the configuration of the present invention, and FIG. 2 is a configuration diagram of a vehicle air conditioner of an embodiment to which the present invention is applied.
FIG. 3 is a block diagram showing a control system of one embodiment, FIG. 4 is a block diagram in which the air conditioning system is a system with three inputs and three outputs, and FIG. 5 is a signal flow diagram of each transfer function, FIG. 6 is a block diagram showing the configuration of the same-dimensional observer, and FIG.
FIG. 8, FIG. 8 and FIG. 9 are flowcharts showing the operation of the control device. M1 …… Refrigeration cycle, M2 …… Cooler, M3 …… Cooling capacity adjusting device, M4 …… Capacity detecting means, M5 …… Temperature adjusting means, M6 ……
Room temperature detection means, M7 …… Capacity setting means, M8 …… Room temperature setting means, M9 …… Capacity deviation accumulating means, M10 …… Room temperature deviation accumulating means,
M11: Control amount calculation means.

Claims (1)

(57) [Claims] 1. A cooler, which is provided in an air passage having a downstream side communicating with a room and cools air by evaporating a refrigerant circulating in a refrigeration cycle, and a cooling capacity of the cooler provided in the refrigeration cycle. A cooling capacity adjusting device for adjusting the cooling capacity, a capacity detecting means for detecting the cooling capacity of the cooling device, and a temperature control for heating the air and adjusting the temperature of blown air, the cooling device being provided downstream of the cooling device in the ventilation passage. Means, room temperature detecting means for detecting the indoor air temperature, capacity setting means for setting a target value of the cooling capacity, room temperature setting means for setting a target value of the indoor air temperature, and the capacity detecting means Detected by the temperature setting means, the capacity deviation accumulating means for accumulating a deviation between the target capacity set by the capacity setting means, the detected room temperature detected by the room temperature detecting means, and the room temperature setting means set. Room temperature deviation accumulating means for accumulating deviation from the target room temperature, at least the adjustment amount of the cooling capacity adjusting device and the adjustment amount of the temperature adjusting means as control inputs, and at least the cooling capacity and the room air temperature. A dynamic model of the system as a control output stores at least the detection capability, the detected room temperature, the capacity deviation accumulated value, and a feedback gain as an additional integral optimal regulator that controls the room temperature deviation accumulated value by feedback. An air conditioning control device, comprising: a feedback control amount calculation means for calculating a command value of the control input based on the feedback gain.