JPH02169948A - Operation control device for air-conditioning apparatus - Google Patents

Abstract

PURPOSE:To improve the feeling of air-conditioning by converting a difference between temperature in each room and set temperature to a load coefficient, calculating the total load of all room units on the basis of the load coefficient and the capacity of each room heat exchanger, and controlling the operation capacity of a compressor in response to the total load. CONSTITUTION:In cooling operation, difference temperature computation means 51 computes a difference between room temperature of each room unit A-C detected by room temperature detector means Th8 and set temperature, which is converted to a load coefficient. The total load of all room units A-C is computed by load computation means 53 on the basis of the load coefficients of the room units A-C and the capacity of a room heat exchanger 7. Control means 54 controls output frequency of an inverter 11 in response to the total load. Thereupon, once the room temperature approaches the set temperature to reduce the difference temperature, the capacity of the condenser 1 is controlled such that it is rapidly reduced. Accordingly, each room temperature is kept at the close vicinity of the set temperature without experiencing a rapid change.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an operation control device for a multi-type air conditioner, and particularly to measures for improving control performance.

(Prior Art) Conventionally, as disclosed in Japanese Patent Publication No. 60-12532, for example, in an air conditioner equipped with a compressor driven by an inverter with variable operating frequency, as shown in FIG. Let the difference in temperature ΔT between and the set temperature be the air conditioning load,
The variation range of the temperature difference ΔT is divided into a large number of zones, and the step value of the inverter frequency is determined according to the zone corresponding to the temperature difference at that time. For example, during cooling operation, on the side where the temperature difference ΔT decreases, ΔT is 1°C.
The above area is zone (A), the area where ΔT is 0.5 to 1.0℃ is zone (B), the area where ΔT is 0 to 0.5℃ is zone (C), and ΔT is -0.5 to -0.5℃. Zone (D) is the 0℃ area.
, the area where ΔT is -1.0 to 0°5°C is zone (E), Δ
The area where T is -1.0℃ or less is defined as zone (F), and the temperature difference Δ
On the side where T increases, the above zones (B) to (E) are each set to be shifted upward by 0.5°C,
The temperature difference ΔT is attempted to converge to the control target value of zero by sequentially decreasing the inverter frequency in zones (A) to (E) and controlling the compressor to stop in zone (F). In other words, as shown in FIG. 8, the room temperature is gradually brought to the set temperature while being varied above and below the set temperature.

(Problem to be solved by the invention) In the case of a so-called pair machine in which one indoor heat exchanger is connected to one compressor, the conventional control described above does not significantly impair the air conditioning feeling. can be controlled.

However, in the case of a multi-type air conditioner in which multiple indoor heat exchangers are connected in parallel to one compressor, the control parameter that determines the capacity of the compressor is ultimately a single one called the total load in each room. On the other hand, since the temperature in each room to be controlled is different, each room does not correspond to a temperature zone as shown in FIG. 9 at the same time. Therefore, with the above-mentioned conventional control, there is a risk that the comfortable feeling of air conditioning in each room may be impaired.

The present invention has been made in view of these points, and its purpose is to control the temperature in each room so that it asymptotically approaches the set temperature from one side of the set temperature.
In a multi-type air conditioner equipped with a plurality of indoor heat exchangers, the objective is to maintain a comfortable air-conditioned feeling equivalent to that of a bare machine in each room.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention does not directly use the temperature difference between the indoor intake air temperature and the set temperature as an air conditioning load, but compresses it as the temperature difference decreases. The problem lies in once converting to another parameter that rapidly reduces the capacity of the machine.

Specifically, the first solution is as shown in FIG.
), the compressor (1) and the outdoor heat exchanger (3) which are driven by an inverter (11) with variable operating frequency
) for one outdoor unit (X) having an indoor heat exchanger (7), a plurality of indoor units l-(A) to
(C) is assumed to be an air conditioner connected in parallel.

As an operation control device for the air conditioner, there are room temperature detection means (Th7) for detecting the indoor temperatures of each of the indoor units (A) to (C), and each room temperature detection means (T
h7) Receiving the output of ,..., each indoor unit (A)
-(C) temperature difference calculation means (51) for calculating the temperature difference between the indoor temperature and the set temperature, and each temperature difference calculation means (51).
), . . . converting means ( 52).

..., all the indoor units (A) to (C) based on the load coefficient calculated by each conversion means (52), ... and the capacity of each indoor heat exchanger (7), ... load calculation means (53) for calculating the total load of the inverter (11); and control means (54) for controlling the output frequency of the inverter (11) according to the total load calculated by the load calculation means (53). The configuration is such that the

As shown in FIG. 1 (not including the broken line part), the second solution means changes the load coefficient characteristics of the converting means (52) in the first solution method such that the load coefficient becomes a predetermined value when the temperature difference is higher than a predetermined value. In the upper limit zone where the temperature difference is greater than or equal to the upper limit value, in the lower limit zone where the load coefficient is zero when the temperature difference is below zero, and in the range where the temperature difference is zero and is lower than the above predetermined value, the load coefficient has a decreasing rate with respect to the decrease in the temperature difference. It has a plurality of intermediate zones that gradually increase and decrease from the upper limit value to zero.

A third solution means, as shown in FIG.
In addition, when the temperature difference value calculated by the temperature difference calculation means (51) is in the same intermediate zone for a predetermined period of time, a carry means (51) for carrying up and changing the load characteristic at that time to a value of a zone one level higher;
55).

(Function) With the above configuration, in the invention of claim (1), during the cooling operation of the device, the temperature difference calculation means (51) detects each indoor unit (A) to (C
) is calculated, and the difference in temperature between the room temperature and the set temperature is calculated, and the conversion means (5
2), the temperature difference value is converted into a load coefficient, and then the load calculation means (53) converts each indoor unit (A) to (C
) and the capacity of the indoor heat exchangers (7), . . . , the total load of all indoor units (A) to (C) is calculated.

The control means (54) then controls the output frequency of the inverter (11) according to the total load.

In that case, the conversion means (52) converts the current temperature difference value into a load coefficient based on the load coefficient characteristic that changes so that the rate of decrease gradually increases as the temperature difference decreases. Therefore, when the room temperature approaches the set temperature and the temperature difference decreases, the temperature difference value is reduced at an accelerated rate, and the capacity of the compressor (1) is rapidly controlled to be small.

Therefore, the temperature difference in each room asymptotically approaches zero from one side, and the room temperature in each room is maintained close to the set temperature without sudden changes, and a comfortable air-conditioned feeling is maintained in each room. Become.

In the invention of claim (2), the load coefficient is set to the upper limit value "1" in the upper limit zone where the temperature difference is equal to or higher than the predetermined value.
For example, during cooling operation, even if the temperature difference is large, the operation is performed without any increase in air conditioning capacity, and overshoot of the total load to the negative side due to excessive air conditioning capacity is effectively prevented. Furthermore, since the load coefficient becomes zero in the lower limit zone where the temperature difference is below zero, when the room temperature in each room becomes below the set temperature, the total load is converted to zero. Furthermore, in the intermediate zone, the plurality of divided zones change with the same decreasing characteristic as the invention of claim (1), so that the same effect as the invention of claim (1) can be obtained. Therefore, the effect of the asymptotic control of the invention of claim (1) can be more effectively obtained.

In the invention of claim (3), as the function of the conversion means (52) in the invention of claim (2), the carry means (55
), when the temperature difference value remains in the same intermediate zone for a predetermined period of time, the load characteristic at that time is carried over to the load coefficient value of the zone one level higher, so the operating capacity of the compressor (1) becomes higher. Even if the room temperature is controlled toward the set temperature and is difficult to asymptotically approach the set temperature during asymptotic control as in the invention of claim (2) above, the approach of the room temperature to the set temperature is accelerated.

(Example) Hereinafter, examples of the present invention will be described based on FIGS. 2 to 7.

FIG. 2 shows the overall configuration of an air conditioner according to an embodiment of the present invention, in which (X) is an outdoor unit, and (A) to (C) are a plurality of indoor units connected in parallel to the outdoor unit (X). It is a unit. The above outdoor unit (X) is equipped with an inverter (
11) Compressor (1) driven by variable operating frequency
A four-way switching valve (2) switches between the solid line in the figure during heating operation and the broken line in the figure during cooling operation to switch the flow cycle of the refrigerant discharged from the compressor (1).
), an outdoor heat exchanger (3) equipped with an outdoor fan (3a), which functions as an evaporator during heating operation and as a condenser during cooling operation, and which adjusts the refrigerant flow rate during cooling operation,
An outdoor electric expansion valve (4) that reduces the pressure of refrigerant during heating operation, a receiver (5) that stores liquid refrigerant, and an accumulator (8) that removes liquid refrigerant from the refrigerant sucked into the compressor (1).
are arranged as main equipment, and each of the above-mentioned equipment is connected through refrigerant piping (9) so that refrigerant can flow therethrough.

In addition, inside the outdoor unit (X), each of the above indoor units)
Branch pipe (9a) of refrigerant pipe (9) to (A) to (C)
~(9C) are arranged, and each of the branch pipes (9a)~(
9C) includes an indoor electric expansion valve (6) that reduces the pressure of the refrigerant during cooling operation and adjusts the flow ffi during heating operation.
is interposed. On the other hand, each indoor unit (A) has
The indoor heat exchanger (7), which functions as a condenser during heating operation and as a condenser during cooling operation, connects each branch pipe (9a) to (
9C). In other words, each of the above devices (1)
- (8) are connected to the refrigerant pipe (9) so that the refrigerant can flow in sequence, and have a heat pump effect of transferring heat obtained by heat exchange with outdoor air to indoor air in the outdoor heat exchanger (3). A main refrigerant circuit (10) is configured.

Furthermore, many temperature sensors are arranged in the device, and in the outdoor unit (X), (Thl) is the discharge pipe (
(9f) is the discharge pipe sensor that detects the temperature of the discharged gas, (T h2) is the suction pipe sensor that detects the temperature of the suction gas that is located in the suction pipe (9g), and (T ha) is the outdoor heat exchanger. An outside air temperature sensor (Th4) is placed at the air inlet of the outdoor heat exchanger (3) to detect the outdoor air temperature. The outer coil sensors for detection (Th5), . . . are branch pipes (9a).

The liquid pipe sensors (The) are arranged on the liquid side of the refrigerant and detect the temperature of the supercooled refrigerant. This is a gas pipe sensor that detects the temperature of superheated gas refrigerant.

On the other hand, on the indoor units (A) to (C) side, (Th
7) , . . are room temperature sensors arranged at the air suction ports of each indoor heat exchanger (7), . . as room temperature detection means for detecting the indoor temperature Ta; (Th8) , . This is an inner coil sensor that is placed in the indoor heat exchanger (7), and detects its temperature.

In other words, during cooling operation, the gas pipe sensor (Th6)
,... and the inner coil sensor (The).

The opening degree of each indoor electric expansion valve (6), etc. is controlled according to the degree of superheating of the refrigerant detected as the difference in temperature from the detected value of the liquid pipe sensor (Th5) during heating operation. )
,... detection value and inner coil sensor (Th8).

The refrigerant flow rate is controlled by adjusting the opening degree of each indoor electric expansion valve (6), depending on the degree of supercooling of the refrigerant detected as the temperature difference between the detected value of the refrigerant and the detected value of the refrigerant. There is.

Note that (12) is the discharge pipe (9f) of the compressor (1).
a first bypass passage (13) that connects the suction pipe (9g) on the upstream side of the accumulator (8) so that refrigerant can flow therebetween;
Reference numeral 4 indicates a first electromagnetic opening/closing valve that controls opening and closing of the refrigerant flow in the first bypass path (12), and (]4) a capillary (14) that reduces the pressure of the refrigerant. The valve (13) opens, allowing a portion of the hot gas discharged from the compressor (1) to bypass from the main refrigerant circuit (10) to the first bypass path (12), and bypasses the hot gas discharged from the compressor (1) to the capillary (14).
) to reduce the pressure and then flow it to the suction side to reduce the capacity.

In addition, (3b) and (3c) are the outdoor heat exchanger (3
) and are connected in parallel between the liquid pipe (9d) and the gas pipe (9e) by branch pipes (9h) and (9i), respectively.

A second electromagnetic on-off valve (15) for controlling the opening and closing of the refrigerant flow is interposed in one of the branch pipes (91),
Normally, the operation is performed with the second electromagnetic on-off valve (15) open, but depending on the operating condition, the heat exchange area of the outdoor heat exchanger (3) is reduced by closing the second electromagnetic on-off valve (15). This is done to reduce the capacity of the system.

Next, FIG. 3 shows the internal configuration of the controller (16) and external equipment connected to the controller (16),
(MC) is the motor of the compressor (1), and the motor (MC) includes a relay contact (52C-+), a noise filter (22), a rectifier circuit (23), and a choke coil (24). ) and the inverter (11) in turn to an AC three-phase power source (21). Also, (MFI
) is the motor of the outdoor fan (3a), (52C), (
2OR2), (2OR4) and (20R5) are the inverter (11), the first electromagnetic on-off valve (13),
An electromagnetic relay that operates a second electromagnetic on-off valve (15) and a four-way switching valve (2), each of which is connected to a single-phase component of the three-phase AC power source (21), and It is also connected to the controller (16) so that signals can be exchanged.

Here, the motor (MFl) of the outdoor fan (3a) is configured such that its connection to the AC power source can be switched in two directions, and an electromagnetic relay (not shown) built in the controller (16) is used. When the normally closed contact (52'FH) of the electromagnetic relay is connected, the standard high air flow is applied, and the normally open contact (52'FH) of the electromagnetic relay is connected.
52FL) is connected, the outdoor fan (3a) is operated on the low air volume side. moreover,(
EVo), (EV+) and -(EV3) are the outdoor electric expansion valve (4) and the indoor electric expansion valve (EV3), respectively.
6).

This is a stepping motor that drives the opening adjustment mechanism CL'I (not shown). Each of the external devices listed in L is connected to the controller (16) so as to be able to send and receive signals, and the operating state thereof is controlled by the controller (11-).

Furthermore, (63H2) is a pressure switch for high pressure control during heating operation, and this switch (63H2) is signal-connected to the controller (16) through a connection terminal (CN3).

Further, inside the controller (16), normally open contacts (RY+) to (RY4) of electromagnetic relays are connected in parallel to the single-phase AC power source. These are, in order, the electromagnetic relay (52C) of the inverter (11), the electromagnetic relay (2OR2) of the first electromagnetic on-off valve (13), the electromagnetic relay (20R4) of the second electromagnetic on-off valve (15), and the four-way switching valve ( 2
) are connected in series to the coils of the electromagnetic relays (20R5), and are opened and closed in response to signals from the controller (16) to turn each of the electromagnetic relays on and off.

The controller (16) is connected so as to be able to input signals from each of the sensors (Thl) to (Thehe) on the outdoor side, and also has a serial transmission circuit (16) connected to the indoor side.
25), each indoor sensor (T h7) to (T
h8) signal can be input.

Furthermore, the controller (16) has a built-in storage device (19) that stores control programs and the like. At t(19), a room temperature sensor (T h
Conversion characteristics for converting the air conditioning load detected in step 7) into an air conditioning load coefficient α are stored in advance. That is, as shown in FIG. 6, for example, there is an upper limit zone where the load coefficient α is the upper limit value "1" in a range where the temperature difference ΔT is a predetermined value of 2.0°C or more, and an upper limit zone where the load coefficient α is the upper limit value "1" in a range where the temperature difference ΔT is 0°C or less. A lower limit zone is set where the load coefficient α becomes rOJ. Also, the temperature difference ΔT is 0
In the intermediate zone ranging from ℃ to 2.0℃, ΔT is 0 to 0
．． A first zone at 5°C, a second zone at 0.5-1.0°C,
An intermediate zone consisting of a third zone of 1.0 to 1.5°C and a fourth zone of 1.5 to 2.0°C is set. Here, in the above intermediate zone, the load coefficient α is a straight line α-1
It changes stepwise along a hyperbola (broken line curve in the figure) that asymptotically approaches ΔT-0, and in the fourth zone it changes to rO,97J, in the third zone to rO,9J, and in the second zone Then ro, 75J, in the 4th zone "0
”. In other words, the load coefficient α increases by increasing the rate of decrease as the temperature difference ΔT decreases.
” to “0”.

Note that the capacity setting value C corresponding to the capacity ratio of each indoor unit (A) to (C) is set as an integer from "1" to "10".

In the figure, (26) is a sawtooth wave smoothing circuit, (2
7) is a transmission synchronization circuit, (28) is a device protection circuit, (
63H+) is a high pressure switch for equipment protection, (49F
) is a protective thermostat for the motor (MFI) of the outdoor fan (3a), and (CN51) is an output terminal for outputting a signal to the drive circuit (not shown) of the inverter (11).

During cooling operation of the device, the four-way switching valve (2) switches to the side shown by the broken line in the figure, and with the outdoor electric expansion valve (4) open, the opening degree of the indoor electric expansion valve (6), etc. is changed. The operation is performed while adjusting according to the degree of superheating, and the discharged refrigerant is condensed in the outdoor heat exchanger (3), reduced in pressure by each indoor electric expansion valve (6), and then transferred to each indoor heat exchanger (7). )... On the other hand, during heating operation, the four-way switching valve (2) switches to the solid line side in the figure, and the opening degree of each indoor electric expansion valve (6),... opens. The outdoor electric expansion valve (4) is operated while the opening degree of the outdoor electric expansion valve (4) is appropriately adjusted in a somewhat cold state, and the discharged refrigerant is condensed in each indoor heat exchanger (7), etc., and the outdoor electric expansion valve (4) is condensed. 4)
It is depressurized and circulated to be evaporated in the outdoor heat exchanger (3).

The controller (16) controls the operation of each device of the apparatus according to input values from each sensor.

The contents will be explained based on the flowchart of FIG. 4. In step S1, each sensor (T hl) to (T
h8) is input, and in step S2, the temperature difference ΔTi (1-1 to 3) is calculated from the room temperature Ta detected by the room temperature sensor (Th7) and the set temperature Ts for each indoor unit (
A) to (C) are calculated, and in step S3 it is determined whether all indoor units (A) to (C) are in the thermo-off state. If the determination is YES, thermo-off operation is performed in step S4. . On the other hand, the thermostat is not turned off even on -
o, in step S5, the temperature difference Δ in each indoor unit (A) to (C) is determined based on the characteristics shown in FIG.
T1 is converted into an air conditioning load coefficient α1 (I-1 to I-3), and in step S6, each indoor unit (A) to (C
) is multiplied by the capacity setting value CI set for each indoor unit (A) to (C) to obtain the required load Di(1-1
~3), and in step S7, each indoor unit (A
) to (C) required load, ,D2. The sum of D3, that is, the total load ΣDl (=D1 +D2 +D3) is calculated.

When the total indoor load ΣD1 is determined by the above control, it is determined in step S8 whether the device is currently in the cooling mode or dry mode, and if YES, the total load ΣD1 is determined in step S9.
It is determined whether or not D1 is smaller than 1 to the first set value which is the lower limit of the normal control region. If the first set value is larger than 1, in step SIO, the frequency is sequentially adjusted as the value of load ΣD1 increases. Perform normal control to increase F.

On the other hand, if the first setting value is as follows, step S11
Then, the electromagnetic relay (2OR2) is turned on to open the first electromagnetic on-off valve (13) of the first bypass path (12), and the output frequency F of the inverter (11) is increased compared to the normal control. .

In other words, a portion of the hot gas is bypassed to the first bypass path (12), and the system is controlled to operate at a low capacity.

After performing the low capacity control as described above, in step S12,
It is determined whether the total load ΣD1 is less than or equal to the second set value, which is even smaller than the first set value, 1, and if it is larger than K2, it is left as it is, and if it is below, step S+
3, set the air volume of the outdoor fan (3a) to low air ffi rLJ
The heat exchange area of the outdoor heat exchanger (3) is reduced, and the outdoor heat exchanger (3) is controlled to operate at a lower capacity.

On the other hand, if the determination in step S8 is No, that is, during heating operation, in step S+4, the total load ΣD1 is set to a third setting value corresponding to the minimum capacity of the compressor (1) during heating operation (30 Hz in this example). If ΣDi≦3, normal control is performed in step SI5, but if ΣDi≦3, the air volume of the outdoor fan (3a) is switched to the low air volume rLJ side in step SI6.

Next, in step SI7, it is determined whether the total load ΣDi is 4 or less to a fourth set value smaller than the third set value, and ΣD
If i>K+, leave as is; if ΣD1≦4,
In step SI8, the electromagnetic relay (20R4) is turned on to close the second electromagnetic on-off valve (15) to reduce the heat exchange area of the outdoor heat exchanger (3).

Thereafter, the process proceeds to step S+9, where it is determined whether the total load ΣDi is less than or equal to the fifth set value, which corresponds to the lowest range limit value, which is smaller than the fourth set value, 4, by 5 or less. and,
If ΣD1 > Ks, leave as is; if ΣD1≦5, open the first electromagnetic on-off valve (13) in step Si,
After bypassing the hot gas and controlling the operation at a lower capacity, the inverter (
11) Increase the frequency F.

When the control in each step S Ill SS +3, SI5, or S2+ is completed, the process waits for the sampling time to elapse in step S22, returns to step S5, and repeats the above control.

FIG. 5 shows the subroutine of step S5 in the above flow, and in which zone the temperature difference ΔT is set in the storage device (19) in step R1 for each indoor unit (A). If it is in the upper limit zone, the load coefficient α is set to "1" in step R2, and if it is in the lower limit zone, the load coefficient α is set to "0" in step R3. If it is in the intermediate zone, the load coefficient α is set to "0" in step R4. After setting the load coefficient α to a value αn (n=1 to 4) corresponding to one of the first to fourth zones, in step R5, it is determined whether or not the same zone is present three times in a row from the previous sampling time. If it is the same three times in a row, the load coefficient αn is carried over and changed to the load coefficient αn+1 of the zone one level higher in step R6.

After performing the above control for each of the indoor units (A) to (C) and setting the load coefficient α according to the zone where the temperature difference ΔT exists, the process returns to the main flow.

In the above flowchart, claims (1) and (2)
In the invention, in step S2, the room temperature Ta detected by the room temperature sensor (room temperature detection means) (Th7), .
temperature difference calculation means (
51) is configured, and in steps R2 to R6, based on the load coefficient characteristic that receives the output of the temperature difference calculation means (51) and changes to decrease while gradually increasing the rate of decrease as the temperature difference ΔT decreases. A conversion means (52) is configured to convert the temperature difference value ΔT at that time into a load coefficient α. Also, step s6. According to s7, the conversion means (52)
The load coefficient α calculated by and each indoor heat exchanger (7),...
A load calculation means (53) is configured to calculate the total load ΣDI of all indoor units (A) to (C) based on the capacity C of . Total load Σ calculated in 53)
A control means (54) is configured to control the output frequency F of the inverter (11) according to D1.

Furthermore, in the invention of claim (3), in step R6, when the temperature difference value ΔT calculated by the temperature difference calculation means (51) is in the same intermediate zone for a predetermined period of time, the load characteristics at that time are increased by one level. A carry means (55) is configured to carry over and change the value of the zone.

Therefore, in the invention of claim (1), during the cooling operation of the device, the temperature difference calculation means (51), . The temperature difference ΔT between the room temperature Ta and the set temperature Ts of the units (A) to (C) is calculated, and the temperature difference value ΔT is converted into a load coefficient α by the conversion means (52), . All indoor units (A) to (C) are calculated by the load calculation means (53).
The total load ΣDI is calculated. Then, the control means (54
), the inverter (11
) is controlled.

In that case, the converting means (52) calculates the difference at that time based on the load coefficient characteristic that changes while gradually increasing the rate of decrease as the temperature difference ΔT decreases, as shown in FIG. Since the temperature value ΔT is converted to the load coefficient α, for example, during cooling operation, when the temperature difference between the temperature difference and the intermediate zone is on the large side, the load coefficient α gradually decreases, causing the compressor (1 ) can quickly bring the room temperature Ta closer to the set temperature Ts without reducing the operating capacity too much.
As the room temperature Ta approaches the set temperature Ts, the temperature difference value ΔT
is converted into an α value that decreases at an accelerating rate, and the capacity of the compressor (1) is rapidly controlled to be small.

The above also applies to the heating operation.

In other words, in conventional step control, as shown in Fig. 8, the room temperature Ta once drops below the set temperature Ts and then rises again to exceed the set temperature Ts. I will do it. However, in the case of a multi-type air conditioner in which a plurality of indoor heat exchangers (7), etc. are connected to the compressor (1) in parallel, the compressor (1) For example, the total air conditioning load ΣD1 is
Even if step control is performed to converge to "0" while changing above and below "0", the room temperature Ta in each room does not necessarily converge as shown in FIG.

In contrast, in the present invention, the load coefficient is converted to a very small value near the set temperature Ts, so the load calculation means (53
), the total load is also small, and the air conditioning capacity is controlled to be small at an accelerated rate. Therefore, as shown in FIG. 7, in each room, the temperature difference ΔT asymptotically approaches rOJ on one side, and the room temperature Ta in each room is maintained very close to the set temperature Ts without sudden changes. Therefore, it is possible to maintain a comfortable air-conditioned feeling in each room.

In the invention of claim 2, especially as shown in FIG.
is set to the upper limit value "1", so for example, during cooling operation, even if the temperature difference ΔT is large, the operation is performed without increasing the air conditioning capacity, and the air conditioning capacity is too large and the operation is performed too quickly. Overshoot caused by a drop in room temperature is suppressed as much as possible. In addition, in the lower limit zone where the temperature difference ΔT is "0" or less, the load coefficient α becomes rOJ, so if the room temperature Ta in each room falls below the set temperature Ts, the compressor (1 ) capacity is controlled.

Furthermore, in the intermediate zone, since the plurality of divided zones change with the same decreasing characteristic as the invention of claim (1), the same effect as the invention of claim (1) can be obtained. . Therefore, the effect of the asymptotic 1+11 control of the invention of claim (1) can be more effectively obtained.

In the invention of claim (3), as the function of the conversion means (52) in the invention of claim (a), the carry means (55)
Therefore, when the temperature difference value ΔT is in the same intermediate zone for a predetermined time, for example, in a load zone where the load coefficient α to be converted corresponds to αn, the load characteristic at that time is carried over to the load coefficient value αni1 of the zone one level higher. Since the compressor (
The operating capacity of 1) is controlled to be high, and the above claim (
During the asymptotic control as in the second invention, the room temperature Ta changes to the set temperature Ts.
Even when it is difficult to asymptote to , there is an advantage that the approach is accelerated.

(Effects of the Invention) As explained above, according to the invention of claim (1), an air conditioner in which a plurality of indoor units are connected in parallel to one outdoor unit having a compressor driven by an inverter. The device measures the difference in temperature between the room temperature in each room and the set temperature.
Based on the load coefficient characteristic that changes to decrease while gradually increasing the rate of decrease in response to a decrease in temperature difference, it is converted into a load coefficient, and based on the load coefficient and the capacity of each indoor heat exchanger, all indoor units are After calculating the total load, the operating capacity of the compressor is controlled according to the total load, so the temperature difference approaches asymptotically to "0" and the room temperature in each room is controlled very close to the set temperature. Therefore, it is possible to improve the feeling of air conditioning.

According to the invention of claim (2), in the invention of claim (1), the load coefficient is set to "1" when the temperature difference is above a predetermined value, and to "0" when the temperature difference is "0" or less. Between "0" and the predetermined value, the temperature difference between the plurality of zones decreases while gradually increasing the rate of decrease. Characteristics can be further improved.

According to the invention of claim (3), when converting the load coefficient in the invention of claim (2), if the temperature difference is in the same zone among a plurality of zones for a predetermined period of time, the load coefficient is increased by one level. The above claim (2J
According to the present invention, it is possible to effectively prevent the deterioration of the air-conditioned feeling due to the delay in asymptotic to the set temperature.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the invention. 2 to 7 show embodiments of the invention, FIG. 2 is a refrigerant system diagram of an air conditioner, FIG. 3 is an electric circuit diagram of the controller, and FIG. 4 is a flowchart showing the control contents of the controller. Fig. 5 is a flowchart diagram showing a subroutine of the flowchart in Fig. 4, Fig. 6 is a characteristic diagram showing conversion characteristics from temperature difference to air conditioning load coefficient, and Fig. 7 shows temperature change characteristics by asymptotic control of the present invention. It is a characteristic diagram. Figure 8 is a characteristic diagram showing temperature change characteristics by conventional control.
FIG. 9 is a diagram showing the correspondence between temperature difference and each zone in conventional step control. (1)...Compressor, (3)...Outdoor heat exchanger, (7
)...Indoor heat exchanger, (11)...Inverter, (
51)... Temperature difference calculation means, (52)... Conversion means,
(53) Load calculation means, (54) Control means, (55) Carry means, (Th7) Room temperature sensor (room temperature detection means), (X) outdoor unit,
(A) to (C)...indoor units. Delivery ΔTi Figure Figure

Claims (3)

[Claims] (1) For one outdoor unit (X) having a compressor (1) and an outdoor heat exchanger (3) that are driven by an inverter (11) at variable operating frequencies, an indoor heat exchanger (7)
In an air conditioner in which a plurality of indoor units (A) to (C) are connected in parallel, room temperature detection means (Th7) for detecting the indoor temperature of each of the indoor units (A) to (C),... and receiving the output of each room temperature detection means (Th7),..., each indoor unit (Th7).
A) to (C) temperature difference calculation means (51), . . . for calculating the temperature difference between the indoor temperature and the set temperature;
51) Conversion means that receives the output of , and converts the current temperature difference value into a load coefficient based on the load coefficient characteristic that changes to decrease while gradually increasing the rate of decrease as the temperature difference decreases. (52), . . . and each conversion means (52),
The load coefficient calculated by ... and each indoor heat exchanger (7),
All indoor units (A) to (C) based on the capacity of...
load calculation means (53) for calculating the total load of the inverter (11); and control means (54) for controlling the output frequency of the inverter (11) according to the total load calculated by the load calculation means (53).
An operation control device for an air conditioner, comprising: (2) The load coefficient characteristic of the conversion means (52) has an upper limit zone in which the load coefficient is greater than or equal to a predetermined upper limit value when the temperature difference is greater than or equal to a predetermined value, and a lower limit zone in which the load coefficient is zero when the temperature difference is less than or equal to zero. In a range where the temperature difference is between zero and lower than the predetermined value, the load coefficient has a plurality of intermediate zones in which the load coefficient decreases from the upper limit value to zero while gradually increasing the rate of decrease as the temperature difference decreases. An operation control device for an air conditioner according to claim (1). (3) When the temperature difference value calculated by the temperature difference calculation means (51) is in the same intermediate zone for a predetermined time, the conversion means (52) carries over the load characteristics at that time to the value of the zone one level higher. 3. The operation control device for an air conditioner according to claim 2, further comprising a carry means (55) for controlling the air conditioner.