JPH03279739A - Multiple-room type air conditioner - Google Patents

Abstract

PURPOSE:To obtain a desired dynamic characteristic whenever stability is secured, by calculating the integral gain of an integrating means from at least one of outside air temperature, the sum total of rated capacities of room units being operated, and the rate of change in suction pressure of a compressor. CONSTITUTION:Set values for each room are inputted to a comparing means 31, and is compared with an output from an element 34 having a characteristic inverse to a desired dynamic characteristic. The result of comparison is sent to an integrating means 32, which integrates the input data with respect to time, to obtain an integral gain 1/L, where L is set by a parameter-setting means 23. The parameter-setting means 23 calculates the integral gain from outside air temperature, the number of room units being operated, the sum total of capacitile of the room units being operated, or the rate of change in suction pressure of a compressor. The result of integration by the integrating means 32 is sent to operating circuits for expansion valves for each room, as an expansion valve opening for each room. With the opening of the expansion valve thus controlled, an air conditioner 21 is operated to absorb heat from each room. The characteristic of lowering in room temperature through heat absorption is shown as a room characteristic in a block 22, and a room temperature for each room is determined. The temperature in each room is detected by a room temperature detector, and is inputted to the element 34 having the characteristic inverse to the desired characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to room temperature control in a multi-room air conditioner.

Conventional Technology FIG. 4 is a system configuration diagram of a conventional multi-room air conditioner, in which 1 is a compression @ 3 is an outdoor heat exchanger, which constitutes an outdoor unit 6. Indoor units 7A, 7 & 7C each c
Friend indoor heat exchanger 8A, 8B, 8C1 indoor expansion valve 9A, 9B, 9C, room temperature detector 10A, IOB
, Equipped with IOC, outdoor unit 6 and each indoor unit 7A,
This is a well-known heat pump cycle in which the gas and liquid sides of 7B and 7C are connected through a gas side conduit 13 and a liquid side conduit 12 to form a closed circuit.A refrigerant is sealed inside the closed circuit.

How the multi-room air conditioner works in such a configuration: The outdoor heat exchanger 3 is a condenser; each of the indoor heat exchangers 8A, 8B;
8C acts as an evaporator and cools each room 11A, 11 & IIC by absorbing heat from the air in each room.

Next, the mode of operation of each indoor expansion valve 9A, 9B, and 9C will be explained below. When the opening degree of each indoor expansion valve 9A, 9B, and 9C is increased, the flow rate of the refrigerant increases, the cooling capacity increases, and the temperature of each room is lowered.

The temperature is measured by each room temperature detector 10A, IOB, IO
Detected by C.

In addition, changes in the overall load can be handled by controlling the rotation speed of the compressor 1.

By switching the input and output of the compressor 1 using the Ct west valve (not shown) during heating, the direction in which the refrigerant flows is reversed from that shown in Fig. 4, and the indoor heat exchanger 8A
, 8B, and 8C are condensers, and the outdoor heat exchanger 3 is an evaporator.

Conventional methods for controlling each indoor expansion valve of a multi-room air conditioner employ a so-called PID control method or a table search method that determines the amount of operation according to conditions. In the PID control method, error information with respect to the target value is obtained and the comparison of the error information is calculated.
The manipulated variable is determined by calculating integrals and differentials and adding the calculated results to the controlled object at an appropriate ratio. -People 4 with table search method! Current temperature setting This is a method in which a table of control amounts corresponding to various detected amounts is set in advance.

Further, as a method of controlling the compressor, there is a method of controlling the suction pressure obtained by the suction pressure detector 11 shown in FIG. 4 so as to be constant. When the overall load is large, evaporation speeds up in the evaporators 89B and C of each Sokei internal unit, resulting in an increase in compressor suction pressure.On the other hand, when the overall load is small, evaporation is delayed and the compressor suction pressure increases. Pressure decreases. Therefore, the control number for compressor 1 is: If the compressor suction pressure is higher than the target, the compressor rotation speed is increased; if it is lower than the target, the rotation speed is decreased.4 By controlling the compressor in this way, the rotation speed is You can show your abilities.

The distribution of refrigerant in the indoor unit and outdoor unit can be maintained approximately constant.

Problems to be Solved by the Invention However, in such multi-room air conditioners, it goes without saying that the operating conditions (4 = For example, if the number of units in operation changes, the characteristics of the target will change, and the operation may be stopped for a long time. It is well known that there is a phenomenon in which the suction pressure of the compressor changes in the opposite direction to normal, and the characteristics are significantly different from those in steady state. In the PID control method, the stability and response performance of the control system both change, and in order to ensure stability, the problem is that response performance must be sacrificed. There was also the problem that even if the number of machines in operation increased, the response performance would change. The number of combinations of operating conditions becomes enormous, and the size of the table increases explosively, making it impossible to handle it realistically.

In addition, +1 in the compressor control system.As shown in Figure 9, as time passes after the compressor has stopped and the refrigerant imbalance increases, when the compressor is started, the suction pressure drops significantly and does not return to the target value. occurs. That is, a situation occurs in which the suction pressure decreases and the compressor rotational speed is lowered.

In this case, the suction pressure cannot reach the target value.

Means for Solving the Problems First aspect of the present invention (Main) A means for obtaining a characteristic substantially corresponding to an inverse characteristic of a desired control dynamic characteristic, an integrating means is provided, and the detected room temperature is input to the inverse characteristic means; The output of the means is compared with the set value, and the comparison result is input to the integrating means.The output of the integrating means is used to control the opening degree of the expansion valve. Means for outputting the integral gain of the integrating means based on the amount of change is provided.

The second feature of the present invention is to provide a means for substantially matching the inverse characteristic of the desired control dynamic characteristic at startup, an integrating means, a means for substantially matching the inverse characteristic of the desired control dynamic characteristic at steady state, and an integrating means; The obtained compressor suction pressure is used as the input power of the inverse characteristic means, the output of the inverse characteristic means is compared with the target suction pressure, the comparison result is inputted to the integrator means, and the rotation speed of the compressor is controlled by the output of the integrator means. comprising a means for detecting the amount of change in the compressor suction pressure, and activating the inverse characteristic means and the integrating means for the desired control dynamic characteristic using fuzzy logic when the amount of change in the compressor suction pressure changes from negative to positive. Switch from normal use to normal use.

Effect In the first aspect of the present invention (Dai), by inserting the inverse characteristic of the desired dynamic characteristic into the feedback loop, it becomes equivalent to a configuration in which the set human force goes through an element with the desired characteristic of 4L, and if stability can be ensured, the This makes it possible to obtain the desired dynamic characteristics.Furthermore, in response to fluctuations in the controlled object due to changes in operating conditions, the calculated integral gain changes depending on the operating conditions, so it is stabilized.Also, the calculated integral gain (Yo
Since it changes continuously in response to continuous changes in operating conditions, smooth control is achieved without sudden changes in the amount of operation.

Q- Also, in the second aspect of the present invention (Yo), by setting the one that can obtain the maximum amount of operation as the one corresponding to the desired dynamic characteristic for startup, and starting with the compressor rotation speed at the maximum, the suction The pressure decreases rapidly over time. When the refrigerant imbalance is removed, the suction pressure begins to increase to some extent. At this time, the desired dynamic characteristics for steady-state use are smoothly switched using fuzzy logic, so the suction pressure decreases. Also, there is no situation in which the compressor rotation speed does not increase.

EXAMPLE Hereinafter, the first example of the present invention will be explained based on the drawings. FIG. 1 is a configuration diagram of a control system of a multi-room air conditioner according to the first invention. The setting values for each room are input to the comparison means 31.
It is compared with the output of the inverse characteristic element 34 of the desired dynamic characteristic. The comparison result is sent to the integrating means 32. In the integrating means 32
Integrate the input value over time. The integral gain is (1/L). Here, L is set by the parameter setting means 23.

The parameter setting means (outside temperature) calculates the integral gain based on the total number of operating units and capacity, and the amount of change in the suction pressure of the compressor.The operating principle of the parameter setting means 23 will be described later.Integration means 32 The result is sent to the expansion valve operation circuit (not shown) of each room as the expansion valve opening of each room.By controlling the expansion valve opening, the air conditioner 2
1 will be operated. This absorbs heat from each chamber. The characteristic that the room temperature decreases due to heat absorption is indicated by a block 22 as a room characteristic. In this way, the room temperature of each room is determined.The room temperature of each room is determined by the room temperature detector 1 shown in Figure 4.
0n Detected by IOB and IOC. The sensed room temperature is input to an element 34 having the inverse of the desired dynamic characteristics to form a control loop.

FIG. 2 shows the operating principle of the control system shown in FIG. 1. In FIG. 1(a), the two blocks of the air conditioner 21 and room characteristic element 22 in FIG. 1 are shown as one block 33 to be controlled, and the transfer characteristic thereof is designated as Gp. Also, the integrating means 32 sets the integral gain to (1/L)
, and rSJ is the Laplace operator. In addition, the desired dynamic characteristic is set as Gm, and the reverse characteristic is set as (1/Gm), and block 3
4 shows 1-. The block diagram in FIG. 2(b) is a modification of the block in FIG. 2(a) into a direct feedback system.

That is, the set value rh<, is input to the comparison element 35 via the block 35 consisting of the desired dynamic characteristic Gm. Comparison element 36 compares with room temperature and inputs the comparison result to inverse characteristic element 34. Although the output of the inverse characteristic element 34 is input to the integrating means 32, the output of the integrating means 32 is input to the controlled object 33 as a manipulated variable. The room temperature detected from the controlled object 33 is fed back to the comparison element 36, forming a control loop. If the round-trip transfer characteristic of the loop is sufficiently large and the loop is stable when the loop is closed, the input/output characteristics of the loop section will be almost 1 when the loop is closed. In addition, the dynamic characteristics of the room temperature viewed from the IR settings almost match the desired dynamic characteristics 35.

FIG. 3C& is a diagram showing the operating principle of the parameter setting means 23 of FIG. 1. The integral gain (1/L) 2- for some values among the outside temperature, the total amount of the number of operating units and the rated capacity, and the amount of change in the suction pressure of the compressor is set in advance. They are Xl, X2. Xl...
・Suppose. Therefore, if the current operating conditions are the same as the set conditions, the value is sent to the integrating means 32.

ζ when the current operating conditions differ from the set conditions.
Calculate the difference between the current conditions and the set conditions. In Fig. 3, ζ is the distance between the current condition and the set condition N1, NλN3. ...is used. As distance, cL, absolute value norm, Euclidean norm, etc. can be considered.

Add and average the set amount based on the distance ratio. When the distance is Ni, the additive average X is determined by the following formula.

X=ΣXi·(1/Ni)/Σ(1/Ni) In this way, the addition average can be calculated and the integral gain (1/L) can be calculated.

With this method, when the operating conditions change and the dynamic characteristics of the controlled object change, the loop is kept stable by obtaining an appropriate integral gain, and the desired dynamic characteristics are always obtained. In addition, since the integral gain changes continuously in response to continuous changes in operating conditions, it is possible to perform control operations while maintaining the control state at all times. In Fig. 3, the input conditions for setting the integral gain are the external temperature and the total rated capacity of the operating indoor units. (can be considered as a three-dimensional hyperplane in a four-dimensional space, and as a result, the calculation method is the same.

Figure 5 shows that the integral gain is set as a fuzzy set for some operating conditions, and the fitness of the set gain is defined as a membership function of fuzzy logic for other operating conditions. Find the degree of conformance to the conditions set for the conditions
This shows a method of fuzzy inferring the integral gain actually used from the integral gain as a fuzzy set. Similarly to Fig. 3, the operating principle is the same even if the explanation is made using one or two parameters (outside temperature and total rated capacity of the operating indoor units), but three parameters are used, such as strength. FIG. 5(a) shows the process of calculating how well the operating conditions match the set conditions. In other words, the degree of conformity to 14-conditions R1, R2, R3, . . . is determined based on the current conditions. FIG. 5A shows an example in which the degree of conformity to condition R1 is 0.4, the degree of conformity to condition R2 is 0.6, and the degree of conformity to condition R3 is 0. FIG. 6(b) shows a fuzzy inference method for obtaining an integral gain X from the degree of fitness, and for condition R1, the integral gain is shown as a fuzzy quantity by a triangle ABC. Similarly, R2 is shown as a triangle DEF, and R3 is shown as a triangle CGH.

Now, since the fitness of condition R1 is 0.4, triangle A
Cut out BC at a height of 0.4 and leave what is shown with diagonal lines. In the same way, triangle DEF is cut out at heights 0 and 6, leaving what is shown within the diagonal lines. Triangle CGH is cut off at height 0, so nothing remains. The center of gravity XG of the shaded area obtained in this way is the number of bundles.The value on the horizontal axis at that time is output as the output, that is, the integral gain. In this way, an integral gain that continuously changes can be obtained in response to continuous changes in operating conditions.

In the first embodiment of the invention, a method using an integrating means is explained. Similar effects can be obtained by using a means having a series combination characteristic of a 5-proportional gain means and a low frequency pass means having a large gain. be able to.

Next, the second invention will be explained using an example. 6th
The figure is a block diagram showing the configuration of the second aspect of the present invention. That is, the detected compressor suction pressure is manually input to the desired dynamic characteristic inverse characteristic means 44 and differentiator means 45. The output of the desired dynamic characteristic inverse characteristic means 44 is manually input to the comparator 41 and compared with the target suction pressure value, and the difference is calculated by the integrating means 4.
Enter 2. The output of the integrating means 42 is input to the air conditioner 21 as a compressor rotation command. The compressor suction pressure is obtained by the air conditioner 21, and thereby a system for controlling the compressor suction pressure to a target value is configured.

Further, the output of the differentiating means 45 is sent to the parameter setting means 43 and used to set the parameters of the desired dynamic characteristic inverse characteristic means 44 and the integrating means.

FIG. 7 is a diagram showing the operating principle of the parameter setting means 43 of FIG. 6. In other words, the plate shows switching between the start-up desired dynamic characteristic and the steady-state desired dynamic characteristic in accordance with the amount of change in the compressor suction pressure, which is the input information. In other words, when the amount of change in the compressor suction pressure is negative, only the desired dynamic characteristics for startup are used. When the amount of change in the compressor suction pressure is between 0 and slightly positive, the desired dynamic characteristics for startup and the desired steady-state characteristics are used. When the amount of change in the compressor suction pressure becomes sufficiently positive, only the steady-state dynamic characteristics are used. Desired dynamic characteristics at startup are determined so that the amount of operation (rotation command) of the compressor is immediately maximized.

FIG. 8 shows the control results based on the contents of the parameter setting means shown in FIG. The compressor suction pressure is rapidly reduced by control according to the startup dynamic characteristics.

Even if there is a large imbalance in the refrigerant, as time passes and the refrigerant sent out from the compressor begins to be sucked in again, the change in suction pressure will start to increase. At this time, fuzzy logic switches to a steady-state model.
The compressor rotation command decreases. When the compressor rotation command decreases, the suction pressure increases, and when it rises and exceeds the target value, the compressor rotation command is increased again. In other words, feedback control is realized. Thereby, the compressor suction pressure is controlled to the target value.

Regarding the second aspect of the present invention, the power level was explained using the suction pressure in cooling.In heating, the load information of the indoor unit is detected by the compressor discharge pressure, and the compressor rotation command is issued so that the discharge pressure is constant. the force by which the manipulation is carried out (it is clear that the invention can be applied in this case as well).

As described in detail, the present invention provides a method that allows a multi-room air conditioner to stably follow the set value even if the operating conditions change significantly. can be kept constant.

Furthermore, stable startup can be performed even when the refrigerant bias is significantly different.

[Brief explanation of drawings]

FIG. 1 shows the configuration of the control system according to the first embodiment of the present invention 8 - Configuration of a multi-room air conditioner. FIG. Fig. 6 shows the block configuration of the control system according to the second embodiment of the present invention. Fig. 7 shows the operating principle showing the parameter setting principle of the control system of Fig. 6. Fig. 8 shows the control system of Fig. 6 applied. Figure 9 is a starting characteristic diagram when the desired dynamic characteristics for starting are not set.

Claims (6)

[Claims] (1) One outdoor unit consisting of a compressor, an outdoor heat exchanger, and an outdoor expansion valve is connected in parallel with multiple indoor units each equipped with an indoor heat exchanger and an indoor expansion valve, and each of the indoor units is connected in parallel. Each room temperature detector detects the temperature of each room in which the room is installed, and each set room temperature detector detects each room temperature setting value of each room. A multi-chamber air conditioner that controls the plurality of expansion valves, wherein means for obtaining desired dynamic characteristics substantially inverse to the detected room temperature of each room;
A multi-room air conditioner comprising means for comparing the output of the inverse characteristic means with a set value, and means for time-integrating the comparison result, and controlling the opening degree of the expansion valve of each chamber according to the output result of the integrating means. The integral gain of the integrating means is calculated based on at least one of the outside temperature, the sum of the rated capacities of the indoor units in operation, and the rate of change in the suction pressure of the compressor. Multi-room air conditioner. (2) In claim 1, using a plurality of integral gain values preset according to a plurality of pieces of information such as the outside temperature, the total amount of rated capacity of the operating indoor unit, and the amount of change in the suction pressure of the compressor, The current outside temperature, total amount, and amount of change in suction pressure,
Weighted averaging of the integral gain value is performed based on the ratio of the difference between each of the set outside temperatures, the total amount, and the amount of change in suction pressure;
A multi-room air conditioner characterized in that the obtained average value is used as an integral gain of an integrating means. (3) In claim 1, a plurality of integral gain values based on the outside temperature, the total amount of the rated capacity of the operating indoor unit, and the amount of change in the compressor suction pressure are set as a fuzzy set, and the current outside temperature and the total sum are set as a fuzzy set. Using the amount and suction pressure change amount, find the goodness of fit for each of the set fuzzy sets, perform fuzzy inference on the integral gain value based on the obtained goodness of fit,
A multi-room air conditioner characterized in that an inference result is used as an integral gain of an integrating means. (4) The multi-room air conditioner according to claim 1, characterized in that, instead of the integrating means, means having a characteristic in which a high gain proportional gain means and a low frequency band pass characteristic means are coupled in series is used. (5) One outdoor unit consisting of a compressor, an outdoor heat exchanger, and an outdoor expansion valve is connected in parallel with multiple indoor units each equipped with an indoor heat exchanger and an indoor expansion valve, and each of the indoor units is connected in parallel. means for detecting the suction pressure of a compressor suction section connected to the compressor, and the rotation speed of the compressor is adjusted to match the compressor suction pressure to a preset compressor suction section pressure target value. A multi-chamber air conditioner for controlling a multi-chamber air conditioner, means for obtaining desired dynamic characteristics substantially inverse to the detected compressor suction pressure;
A multi-chamber air conditioner comprising means for comparing the output of the inverse characteristic means and a suction pressure target value, and means for time-integrating the comparison result, and controlling the rotation speed of the compressor based on the output result of the integrating means. There is provided a desired dynamic characteristic for the start of operation and a desired dynamic characteristic for steady operation, and means for obtaining the amount of change in the compressor suction pressure; A multi-room air conditioner characterized in that the two desired dynamic characteristics are switched using fuzzy logic based on the quantity. (6) The multi-room air conditioner according to claim 5, wherein switching of the fuzzy logic starts when the sign of the amount of change in suction pressure changes from negative to positive.