JPS62258946A - Air-conditioning machine - Google Patents

Abstract

PURPOSE:To permit accurate control of the capacity of a compressor and improve the comfortable feeling of users by a method wherein an airconditioning load detecting means is provided and the capacity of the compressor is controlled in accordance with the increase or decrease of detected air-conditioning load during a predetermined time. CONSTITUTION:A refrigerant cycle is constituted by connecting a plurality of units to an outdoor unit provided with a compressor 1. An airconditioning load detecting means 31 detects an air-conditioning load as a reference load in case the air- conditioning load in a room is higher than the reference load. In case the load in the room is smaller than the reference load, a compressor controlling means 37, which detects the air-conditioning load, controls the capacity of the compressor 1 in accordance with said detected air-conditioning load when the detected load not increase or decrease within a predetermined periof of time, however, the means 37 increases or decreases the capacity of the compressor 1 in accordance with the amount of increase and decrease when the detected air-conditioning load is increased or decreased within the predetermined period of time. According to this method, delicate control in accordance with the air-conditioning load may be effected accurately, therefore, the comfortable feeling of users may be improved.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to an air conditioner, and in particular, a refrigerant cycle is constructed by connecting an indoor unit to an outdoor unit having a compressor with variable compression capacity. It is related to air conditioners.

(Prior Art) An air conditioner having the above configuration, such as an inverter multi-air conditioner, is known as described in Japanese Patent Application Laid-Open No. 59-13841. In this type of air conditioner, when the number of indoor units being operated or the indoor air conditioning load changes, the compression capacity of the compressor changes accordingly.
That is, it is necessary to control the inverter frequency. In the conventional apparatus described above, the compression capacity is controlled as follows. For each indoor unit, the required control frequency is determined from the temperature difference between the room temperature and the set temperature, and the maximum required control frequency is set as the required standard frequency, and the required standard frequency is set according to the number of operating indoor units. This is then output to the inverter. In other words, when there are many operating units (for example, 3 units), the above-mentioned required reference frequency is set as the inverter frequency, whereas when there is a small number of operating units (for example, 1 unit), a frequency smaller than the above-mentioned required reference frequency is set as the inverter frequency. It is. In addition, in the above device, when the temperature difference between the room temperature and the set temperature decreases, that is, when the indoor air conditioning load decreases, the control request frequency is decreased accordingly, and the inverter frequency is thereby decreased. control is in place to ensure that

(Problems to be Solved by the Invention) However, when controlling the inverter frequency as described above, the following drawbacks occur. This means that the control required frequency is 90.80.70 for each temperature difference within a predetermined range.
Since the impark frequency is set in stages such as Hz, the range of change in the impark frequency due to changes in room temperature is large (this means that the air conditioning capacity fluctuates greatly, making it impossible to perform fine control of the capacity). In addition, since the inverter frequency is uniquely determined according to the temperature difference and the number of operating units, if the indoor volume becomes too large for the indoor unit, even if there is a margin in the inverter frequency, However, there is a drawback that the air conditioning capacity cannot be increased and, in this respect, accurate capacity control cannot be performed.

This invention was made in order to solve the above-mentioned conventional drawbacks, and its purpose is to perform fine and accurate compressor capacity control according to the load on the indoor side.
Therefore, it is an object of the present invention to provide an air conditioner that can improve the user's sense of comfort.

(Means for Solving the Problems) Therefore, in the present invention, a refrigerant cycle is configured by connecting an indoor unit A to an outdoor unit X having a compressor 1 with variable compression power. As shown in FIG. 1, air conditioning load detection means 31 detects the indoor air conditioning load as a reference load when it is equal to or higher than the reference load, and detects the air conditioning load when it is smaller than the reference load. If the detected air conditioning load does not increase or decrease within a predetermined time, the capacity of the compressor 1 is controlled according to the detected air conditioning load, while if the detected air conditioning load increases or decreases within a predetermined time, the capacity of the compressor 1 is controlled. Compressor control means 37 for controlling to increase or decrease the capacity of the compressor l according to the
This is provided. - (Function) As mentioned above, the air conditioning load detection means 31 detects the air conditioning load as the reference load when it is equal to or higher than the reference load, and detects the air conditioning load as the reference load when it is smaller than the reference load. However, when the load is large, such as immediately after startup, the detected air conditioning load continues to be the reference load, and there is no fluctuation in the detected air conditioning load. Then, the compressor is controlled in accordance with the detected air conditioning load, for example, so that its capacity gradually increases in proportion to the detected air conditioning load. Furthermore, in a state where the detected air conditioning load is smaller than the reference load, the air conditioning load will be detected as is, but since the compressor 1 is in operation, the detected air conditioning load will normally gradually decrease. It turns out. Therefore, in this case, the compression Ill
is controlled so that the capacity decreases in proportion to the amount of decrease, for example, according to the amount of decrease. On the other hand, in a steady operating state in which the room temperature is maintained substantially constant, the detected air conditioning load again remains unchanged, and the capacity of the compressor is controlled in accordance with the detected air conditioning load.

In other words, immediately after startup, etc., the capacity is significantly controlled according to the detected air conditioning load, and when the detected air conditioning load becomes smaller than the reference load, the capacity is reduced according to the amount of decrease in the load, and even more steadily. In the operating state, capacity control is performed in accordance with the detected air conditioning load.

(Example) Next, regarding a specific example of the air conditioner of this invention,
This will be explained in detail with reference to the drawings.

First, Figure 2 shows the refrigerant piping system of a multi-model air conditioner equipped with four indoor units.
X indicates the outdoor unit, and A%B, C, and D indicate the first to fourth indoor units 7), respectively.

The outdoor unit
In addition, during heating operation, there is a four-way switching valve 2 that switches as shown by the broken line in the figure, and an outdoor heat exchanger 3 that has a blower fan 3a.
A first motor-operated valve 4 which is fully opened during cooling operation and controls the degree of superheating of the refrigerant during heating operation, a liquid receiver 5, and a first electric valve 4 which is fully opened during cooling operation, and a liquid receiver 5, which is provided corresponding to each of the above-mentioned indoor units (A...D), It has a total of four second electric valves 6 to 9 that control the degree of superheating of the refrigerant during cooling operation and control the degree of subcooling of the refrigerant during heating operation, and an accumulator 10, and each device 1
10 are connected to each other through refrigerant pipes 11 . . . so that the refrigerant can flow therethrough. Each of the indoor units A to D has an indoor heat exchanger 15 and an electric heater 16 that serves as an auxiliary heat source during heating operation.

The four indoor units 1-A-D are connected to the one outdoor unit X by refrigerant pipes 18, and a refrigerant circulation circuit 19 is formed. That is, during cooling operation, by circulating the refrigerant as shown by the solid line arrows in the figure, the heat absorbed from the room by each indoor heat exchanger 15 is released into the outside air from the outdoor heat exchanger 3, which is repeated to cool each room. While cooling, during heating operation, the refrigerant is circulated as shown by the dashed arrow in the figure.
The heat reception is reversed to that described above, and when the electric heater 16 is activated, each room can be heated together with the heat radiated from the electric heater 16. In the figure, 20 is a capillary chain, and by returning the refrigerant in the liquid receiver 5 to the accumulator 10 through this tube 20, the evaporation temperature during the refrigeration cycle is detected at the outlet of the capillary tube 20. It has become. Further, 22 is a high pressure switch that detects the discharge pressure of the refrigerant, 23 is a liquid shutoff valve, and 24 is a gas shutoff valve.

Next, the operation control circuit of the air conditioner will be explained based on FIG. 3. As shown in the figure, the outdoor unit x has an outdoor control device 25, an inverter 1a is connected to the outdoor control device 25, and the inverter 1a is connected to a drive motor 26 of the compressor 1. Meanwhile, indoor unit 1-A-D
each has an indoor control device 27 (illustration is made for only one indoor unit 1-A, the same applies hereinafter), and a remote control 28 and an indoor thermostat 29 are connected to this indoor control device 27, respectively. ing. Above remote control 2
Reference numeral 8 includes an operation switch for operating the indoor units A to D, and a temperature setting section for setting a desired temperature. And each indoor control device 27...27
and the outdoor control device 25 are connected by a signal line 30, and the indoor control device 27 sends the following three signals to the outdoor control device 25, namely:
A request signal, (2) a ΔT multiplied signal corresponding to the difference between the room temperature determined by the indoor thermostat 29 and the set temperature, and (2) a model code signal are output, respectively. In other words, if we take heating operation as an example,
In the indoor control device 27, as shown in FIG. 4, on the premise that the operation switch is ON (step S1),
ΔT=Detected temperature Calculate general constant temperature (Step S2),
While confirming that ΔT≦O (step S3)
, this signal is changed by ΔT in step S4, and this ΔT
The double signal model code signal is transmitted to the outdoor control device 25.

On the other hand, in the outdoor control device 25, the following (1) to (
7) to determine the ΔT value.

(l) 0≦ΔT signal・・・ΔT value=O(2)-0
,5≦ΔT signal〈0...ΔT value=-0,5(31-
1,0≦∆T signal<-0,5...∆T value--1.0 (4
1-1,5≦ΔT signal<-1,0...ΔT value=-1,5
(51-2,0≦ΔT signal<-1,5...ΔT value=-2
,0(6)-2,5≦ΔT signal<-2,0...ΔT value=
-2,5(7) ΔT times signal -2,5...ΔT
Value=-3,0 and in the outdoor control device 25,
The total temperature difference detection circuit 31 through the air conditioning load detection means for detecting the indoor air conditioning load calculates the sum ΣΔT of the ΔT values of each indoor unit (A to D) requiring operation, and also calculates the maximum temperature. The difference detection circuit 32 determines the maximum of the absolute values of the respective ΔT values. Note that the indoor air conditioning load (absolute value of ΣΔT) detected by the total temperature difference detection circuit 31 has a reference value of 3.0, and all cases of 3.0 or more are detected as 3.0. If it is smaller than that, the value is detected as is, but
The reason for this will be explained later.

In addition, in the outdoor control device 25, each indoor control device 27
...Based on the model code signal output from 27, the load capacity grasping means 33 grasps the load capacity ΣS of all indoor units A to D that are requested to operate (including those whose thermostats are stopped). However, it is done by following the steps below. First, the indoor control device 27
The model code signal output from 27 is determined according to the capacity of each indoor heat exchanger 15,
For example, for a capacity of 2240kcal/h,
0” code, but rQ for 2800kca I/h
OI J is 3550kca 1/h and rolo
, J is also 4500kcal / h rol
1 J, and these codes are stored for each indoor unit A to D. In the outdoor control device 25, the storage unit 34 stores a load capacity value S corresponding to the model code. This load capacity value S is 1t2240kc, +1/h (
The model code rO(jOJ) is set as the standard value "1", and 28
00kcal/h (model code "root") rl
, 25J, 3550kcal/h (model code [
010J) to rl, 5J, 4500kcal/
h (141 type code roll J') is set as "2", and the load capacity grasping circuit 3
In step 5, the above-mentioned load capacity value S is read out for each indoor unit 1-A-D with an operation request, and the sum of these values ΣS
It calculates. Note that the outdoor control device 25 outputs an indoor unit 1-ON signal to the indoor control device 27, thereby controlling the operating states of the indoor units A to D.

In the outdoor control device 25, the total load capacity value ΣS of the indoor units 1-A-D with operation requests as described above,
The maximum absolute values of the ΣΔT value and the ΔT value are determined, and based on these, the frequency of the compressor 1 is controlled by the frequency control circuit 37 as compressor control means. This control method will be explained below using heating operation as an example.

First, the initial setting frequency of the inverter 1a is set, and this initial setting frequency is used at startup, when indoor units A-D return to thermo mode, when the number of operating indoor units A-'-D changes, and when defrost returns. This refers to the frequency that is the control target of the inverter la in the following cases.

This initial setting frequency is determined as shown in Table 1 in relation to the total load capacity value ΣS determined above and the ΔT value which is the maximum absolute value. Note that each initial setting frequency shown in Table 1 is stored in the storage section 38.

Next, the method of controlling the inverter frequency will be explained based on FIG. 5. First, as described in item i, the ΔT flaw signal is converted to the Δτ value (step Sll), ΣS and ΣΔT are calculated (step S12), and then the ΔT value is calculated. Among them, the one with the largest absolute value is read out (step 513). Note that the upper limit of the absolute value of ΣΔT calculated in step 512 is 3.01 as described above, that is, all values greater than 3.0 are 3.01.
It is set to 0.

Next, in step 514, it is determined whether or not the operation of compression '/a1 is continuing, but since it is NO at startup and defrost return, the process moves to step 515, and the data stored in the storage section 38 is An optimal frequency corresponding to the total load capacity ΣS and ΔT value is selected from the initial set frequencies (Table 1), and control is performed to drive the inverter la at this frequency.

Then, the process moves to the next step S16 to perform frequency control, and in step S17, each value of the above ΣS, ΣΔT and the frequency at that time is set to the previous value, and the above step S1
1 and repeats the next control, that is, the same operation as above. In this case, as will be described later, since frequency control is not performed within a predetermined period of time (for example, about 3 minutes) after startup, the inverter frequency will be roughly set to the above-mentioned initial setting value during this period.

Then, in the next control starting from step Sll, since step S14 becomes YES, step 31
8, it is determined whether ΣS has increased compared to the previous time. In the case of NO, that is, if there is no increase in ΣS,
In the next step S19, it is determined whether ΣS is the same as the previous time, and if YES, step S16
Then, the next control is performed in the same manner as above. Further, if NO in step S19, that is, if the indoor units A-D have stopped their thermostats or stopped operating, the process moves to step S15, and the ΣS and Δ at that time are determined.
The initial setting frequency (Table 1) is set again based on T, and steps S16 and subsequent steps are repeated in the same manner as above.

On the other hand, if YES in step S1B, ΣS
has increased, in step S20, it is determined whether the reference setting frequency (Table 1) determined by the increased ΣS and ΔT at that time is equal to or higher than the inverter frequency during the previous control. make a judgment. If YES, control is performed to change the inverter frequency to the reference setting frequency obtained in the above calculation in step S15, and if NO, the previous impark frequency is maintained in step S21. Perform such control,
Next, the process moves to step S16, and similar operations are repeated thereafter.

That is, in the above, in relation to ΣS, the following ■ ~
It performs control that can be summarized in (2).

(2) In a state where there is no change in ΣS, the initial setting frequency is not changed, and the impark frequency is mainly controlled by the subsequent frequency control.

(2) If ΣS decreases, a new initial setting frequency is set based on the decreased ΣS.

■When ΣS increases, a new initial setting frequency is set based on the increased ΣS, but as a result of frequency control,
When the inverter frequency has already exceeded the new initial setting frequency, operation continues at the current inverter frequency.

As described above, when the initial setting frequency of the inverter 1a is set using the total load capacity value ΣS as one of the standards, compared to the case where the number of operating indoor units A-D is used as the standard, , it becomes possible to more accurately grasp the situation in indoor units I-A-D and perform accurate frequency control.

Also, steps S18, 520, S21, and S21 in FIG.
As in S15, when ΣS increases, compare the initial setting frequency after ΣS increase and the current inverter frequency,
If control is performed such that the higher frequency is set as the inverter frequency after the increase in ΣS, the inverter frequency will not decrease when the ΣS increases, and therefore a decrease in heating capacity can be prevented.

Next, the frequency control in step S16 will be explained based on FIG.
The inverter frequency is controlled based on ΔT, thereby achieving even better performance control. Specifically, this frequency control is proportional control (hereinafter referred to as
P control) and integral control (hereinafter referred to as ■ control). First, in step S31,
After startup or the last control, a predetermined period of time (e.g. 30
(seconds) have elapsed. In case of NO,
Proceeding to step 517 (FIG. 5), if YES, the following calculation is performed in the next step S32, and P control is performed to increase or decrease the inverter frequency by the calculated Δ'.

Δr=p・(ΣΔTo−ΣΔTl) In the above, Δf is the frequency to be changed, ΔTO is the current ΔT,
ΔT1 is the previous Δ1゛, and Kp is the regular term coefficient (negative coefficient during heating). Then, in the next step S33, it is determined whether or not Δr obtained above is 0. However, as mentioned above, since the upper limit of ΣΔT is set to 3.0, each Δ′ at indoor units A-D
When the absolute value of r is large, or when each room temperature is very close to the set value and stable, the term (ΣΔTO - ΣΔTl) becomes zero, so
This P control is not performed. Therefore, in such a case, the above step 533 becomes YES, and the next step S
At 34! Advance the control counter by 1. On the other hand, if step S33 is NO, that is, if P control is performed, the control counter 2 is cleared in step S35, and the process proceeds to step 517 (FIG. 5). Then, in step 536, it is determined whether or not the above-mentioned control counter is 6 or more, that is, whether the P control has not been continuously performed more than 6 times. If NO, step 517 (the Figure 5), while Y
If it is ES, control is performed based on the following equation in step S36, and the process moves to step 517 (FIG. 5), whereupon the same operation is repeated.

Δr =KiΣΔTO Note that ΔTO is the same as above, and Ki is an integral term coefficient (a negative coefficient in the case of heating). That is, in step S36, control is performed to increase the inverter frequency approximately in proportion to ΣΔT.

In step S16 of FIG. 5, ΣΔT
The inverter frequency is controlled based on
This can be summarized as shown below.

■If the absolute value of each ΔT is large and the absolute value of ΣΔT continues to be at the upper limit value (3, 0), such as immediately after startup, P control is not performed, and every predetermined time (for example, 3 control is performed every minute), and the inverter frequency is ΣΔT
will increase accordingly.

(2) When each room temperature approaches a set value and the absolute value of ΣΔT increases or decreases, P control is performed, and the inverter frequency increases or decreases in accordance with the change in the absolute value of ΣΔT.

■When the operating state is steady and there is little variation in temperature in each room, ■control is performed and the inverter frequency is set to ΣΔ.
It increases or decreases depending on T.

Next, the operating state of the air conditioner using frequency control as described above will be explained over time based on FIG. 7. First, when the detected air conditioning load (absolute value of ΣΔT) is greater than the reference load 3.0, such as immediately after startup, the detected air conditioning load is continuously detected as the reference load, so there is no change in the detected air conditioning load. Instead, the above-mentioned I control is performed every predetermined time (3 minutes = 30 seconds x 6 times). As a result, Δf=KiXΣΔ
Since Ki and ΣΔT are both negative values during heating, the inverter frequency will gradually increase by Δr (Fig. 7, period T1), and the room temperature will gradually rise and the detected air conditioning load ( If the detected air conditioning load (absolute value of ΔTO) becomes smaller than the reference load 3.0, the detected air conditioning load (absolute value of ΔTO) becomes smaller than the previously detected air conditioning load (Σ
absolute value of ΔT1). As a result, the above P
Control is performed and Δr− becomes ρ・ (ΣΔ↑0−ΣΔ↑1
), and during heating, the inside of the power pump is positive and Kp is negative, so the inverter frequency decreases by Δf, and the rate of rise in room temperature also slows down due to the decrease in heating capacity. Such P control is repeated every predetermined time (30 seconds), and the inverter frequency increases according to the amount of increase when the detected air conditioning load (absolute value of ΣΔT) increases, and when it decreases, the inverter frequency increases according to the amount of increase. will decrease accordingly (
FIG. 7, period T2).

As a result of the above-mentioned control, when the room temperature reaches a steady operating state in which the room temperature hardly changes, the detected air-conditioning load returns to a state where there is no change.In this case, I control is performed again, and ), control is performed to increase or decrease the inverter frequency according to ΣΔT (7th
Figure, period T3).

As described above, according to the frequency control, in a state where the detected air conditioning load is greater than or equal to the reference load, such as at startup,
The inverter frequency is sequentially controlled to increase significantly in proportion to the reference load, and when the detected air conditioning load becomes smaller than the reference load, the inverter frequency is controlled in a small range according to the increase or decrease in the load. Furthermore, in the steady state of operation, the inverter frequency is slightly controlled according to the detected air conditioning load, so it is possible to perform fine heating capacity control with a good 16 degrees.

In the above embodiment, the air conditioning load was detected as the absolute value of ΣΔT, but this is the temperature difference Δ between the room temperature and the set temperature.
It may also be detected as the maximum absolute value of T.Although the explanation above was made during heating operation, it can be carried out in almost the same way during cooling operation, and also in air conditioners other than multi-air conditioners. It is possible to implement

(Effects of the Invention) In the air conditioner of the present invention, as described above, when the air conditioning load is equal to or higher than the reference load, it is detected as the reference load, and when it is smaller than the reference load, the air conditioning load is detected. Furthermore, if the detected air conditioning load does not increase or decrease within a predetermined time, the capacity of the pressure Wi machine is controlled according to the detected air conditioning load, while if the detected air conditioning load increases or decreases within a predetermined time, the Since the compressor capacity is controlled to increase or decrease according to the increase or decrease, immediately after startup, etc., the capacity control is performed to a large extent according to the detected air conditioning load, and when the detected air conditioning load is higher than the standard load. When the air conditioning load becomes smaller, it is possible to perform control to increase or decrease the capacity in accordance with the load increase/decrease, and furthermore, in a steady operating state, it is possible to perform capacity control in accordance with the detected air conditioning load. In other words, it is possible to perform fine control according to the air conditioning load with high precision, and therefore the user's sense of comfort can be improved.

[Brief explanation of drawings]

The figures show an embodiment of the air conditioner according to the present invention, in which Fig. 1 is a block diagram of the overall configuration, Fig. 2 is a refrigerant circuit diagram, Fig. 3 is a block diagram of the control mechanism, and Fig. 4 is a block diagram of the indoor unit. FIGS. 5 and 6 are flowcharts of the control method, and FIG. 7 is an explanatory diagram showing the operating state over time. l...Compressor, 31...Air conditioning load detection means, 37.
...Compressor control means, X...Outdoor unit, A, B,
C, D... Indoor unit lift.

Claims (1)

[Claims] 1. In an air conditioner in which a refrigerant cycle is configured by connecting an indoor unit (A) to an outdoor unit (X) having a variable compression capacity compressor (1), the indoor air conditioning load is higher than the standard load. an air conditioning load detecting means (31) which detects the air conditioning load as a reference load when the load is smaller than the reference load, and detects the air conditioning load when the air conditioning load is smaller than the reference load; While controlling the capacity of the compressor (1) according to the detected air conditioning load,
It is characterized by comprising a compressor control means (37) for controlling the capacity of the compressor (1) to be increased or decreased in accordance with the increase or decrease when the detected air conditioning load increases or decreases within a predetermined time. Air conditioner.