JP3108935B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner provided with an inverter for controlling the operating frequency of an outdoor fan.

[0002]

2. Description of the Related Art Recently, an air conditioner (hereinafter, abbreviated as an air conditioner) has been increasingly controlled by using an inverter device for changing a power supply frequency.
No. 153589 discloses such an air conditioner, and FIG.
It is a block diagram showing an example of a conventional air-conditioning control device.

[0003] In the figure, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a decompression device, and 5 is an outdoor heat exchanger. Make up.

Reference numeral 6 denotes an indoor unit, which is an operation command means 7 for determining on / off of the air conditioner, an indoor unit control means 8 for determining on / off of the indoor fan 9 according to a command from the operation command means 7, and It is constituted by an indoor fan 9. 10 is an outdoor unit, 11 is an outdoor unit control means, 12 is a compressor electromagnetic switch, 13 is a commercial AC power supply, 14 is an outdoor fan, and 15 is an outdoor fan electromagnetic switch.

The indoor unit control means 8 and the outdoor unit control means 11 are operated by a command from the operation command means 7 of the indoor unit 6, and the compressor AC switch 12 is controlled to turn on the commercial AC power supply 13.
It turns off the compressor 1 to drive it, and turns the outdoor fan electromagnetic switch 15 on and off to turn the outdoor fan 14 on and off. Reference numeral 16 denotes a discharge temperature sensor attached to a high-pressure section of the compressor 1. The output of the discharge temperature sensor is input to a discharge temperature detecting means 17, and the detected discharge temperature T _C is compared with a discharge temperature upper limit Tmax by a detected temperature determining means 18. Then, the information is output to the outdoor unit control means 11 as control information.

FIG. 5 is a flowchart showing the operation of the conventional air conditioner, and FIG. 6 is a diagram showing the discharge temperature and the operating characteristics of the outdoor fan 14 in the operating state.
The description will be made with reference to these drawings.

First, in step 1 of FIG. 5 (hereinafter, step is abbreviated as S), if the operation command means 7 is in a stopped state, (S1) is repeated, and if it is in an operated state, a signal f ₁ is outputted.
The indoor unit control means 8 causes eject air by turning on the indoor fan 9, the operation of the outdoor unit controller 11 instructs f ₂ by. As a result, the outdoor unit control means 11 outputs signals f ₃ , f
_{By 4} , the electromagnetic switch 12 for the compressor and the electromagnetic switch 15 for the outdoor fan are respectively turned on, and the commercial AC power supply 13 is supplied to the outdoor fan 14 to be in an operating state.

[0008] Next, in (S2), and determines whether to turn on or off the operation state of the outdoor fan 14 in accordance with the air-conditioning capacity of the device at the outdoor unit controller 11, the electromagnetic outdoor fan accordance with the decision signal f ₄ The discharge operation of the outdoor fan 14 is controlled by turning on / off the switch 15.

[0009] discharge temperature detecting means 17 from the output f ₅ of the (S3) discharge temperature sensor 16 calculates a discharge temperature T _C, (S4)
Then, the detected discharge temperature T _C is input (f ₆ ) to the detected temperature determination means 18, and a determination signal (f ₇ ) is output to the outdoor unit control means 11. If the determination here is smaller than the discharge temperature upper limit value Tmax, the process returns to (S2), and the normal operation of controlling the outdoor fan 14 according to the environmental temperature of the room or the like is performed.

If the discharge temperature T _C is higher in the above comparison, the discharge temperature becomes abnormal and there is a danger that the device will stop functioning due to a high pressure rise. Forcibly turn on (S3).

That is, in FIG. 6, the times T ₀ to T ₁
During, when to stop the outdoor fan 14 for capability saving, discharge temperature T _C in a change in the outside air temperature rises at time T _1, exceeds the discharge temperature limit Tmax, the outdoor fan 14
Forcibly turned on causes lowering the discharge temperature T _C and.

Further, the time T _2, since the discharge temperature T _C is below the discharge temperature limit Tmax, again, turns off the outdoor fan 14 for air conditioning capacity saving. Such an operation is the same at times T ₃ and T ₄ .

[0013]

However, in the above-described conventional air-conditioning control, it is necessary to set a lower discharge temperature upper limit value Tmax in consideration of the overshoot δ of the discharge temperature as shown in FIG. There was a problem that the function of the device was not fully utilized. In addition, since the outdoor fan 14 is frequently turned on and off, the air-conditioning capacity varies, causing uneven cooling, causing discomfort to the human body.
If the discharge temperature is not sufficiently reduced by only the control of 14, the compressor 1 is turned on and off, which has a disadvantage of increasing power consumption.

An object of the present invention is to provide an air conditioner for controlling an air conditioner which solves the above-mentioned conventional problems.

[0015]

According to the present invention, there is provided an air conditioner for inverter-controlling the operation frequency of an outdoor fan, the discharge temperature detecting means for discharging the outdoor fan,
From the detected temperature prediction means for predicting the next discharge temperature from the previous and current discharge temperatures detected by the discharge temperature detection means, the discharge temperature detected last time and this time, and the upper limit of the discharge temperature, A detection temperature determining means for calculating a correction frequency for correcting the operating frequency of the fan and outputting the correction frequency to the frequency command means of the frequency command means of the inverter control means; When the temperature exceeds the upper limit value of the device capacity, the operation frequency of the outdoor fan is corrected to be higher by the correction frequency calculated by the detected temperature determination means.

[0016]

According to the present invention, the next discharge temperature predicted by the detected temperature predicting means 21 during the operation of the compressor 1 in FIG.
If the discharge temperature exceeds the discharge temperature upper limit Tmax, the detected temperature determination means 18 inputs the correction frequency to the frequency command means 19 to change the operation frequency of the outdoor fan 14, so that the discharge temperature upper limit Tmax is set to a value sufficient for the capability of the apparatus. It can be set to the limit of the capacity so that it can be used for the air conditioner, and at the same time, the frequency of turning on and off the outdoor fan 14 and the compressor 1 is greatly reduced, and the power consumption is small, so that the air conditioning comfortable for the human body can be performed. Will be possible.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is a block diagram of an air conditioner according to an embodiment of the present invention, wherein 1 to 18 have the same or the same functions as those in FIG. 4, and a detailed description thereof will be omitted. In addition, 19 is frequency command means for determining an operation frequency, 20 is inverter control means, 21 is an outdoor fan
A detection temperature predicting unit 14 predicts the next discharge temperature from the discharge temperature detected last time and the discharge temperature detected this time.

The present invention is configured as described above, and its operation will be described in detail below with reference to the operation flowchart of FIG. 2 and the control characteristic diagram of FIG.

[0020] First, in referring to FIG. 2 (S1), if it is in command "Stop" operation command means 7 by the signal f ₁ repeat (S1), if a command for "operation", the indoor by machine controller 8 turns on the indoor fan 9, instruction f ₂ to the operation to the outdoor unit control means 11 (S1). As a result, the outdoor unit control means 11 turns on the compressor electromagnetic switch 12 in response to the signal f ₃ , and supplies power to the compressor 1 from the commercial AC power supply 13.

Further, the outdoor unit control means 11 activates the operation frequency command means 19 by the signal f _8, to determine the operating frequency of the outdoor fan 14 to satisfy the capacity required for the apparatus by the indoor temperature and the like, the operating frequency information to command f ₉ to the inverter control unit 20 (S2).

The inverter control means 20 forms an inverter output waveform according to the commanded operating frequency, starts the outdoor fan 14 and puts the device into an operating state.

Next, the outdoor fan 14 detects the discharge temperature T _C of the air discharged from the output f ₅ of the discharge temperature sensor 16 by the discharge temperature detecting means 17 (S3).

Next, the detection output f from the discharge temperature detecting means 17
_{In the} detected temperature predicting means 21 according to ₁₀ , the time T ₁
Assuming that the discharge temperature calculated in the above is T _C 1 and the discharge temperature calculated at the current time T ₂ is T _C 2, the following general formula (1) and
Calculating the discharge temperature T _C 3 in the next time T ₃ (2)
(S4).

[0025]

(Equation 1)

Next, in the detection temperature determining means 18, calculates the detected temperature prediction unit 21 compares the next discharge temperature T _C 3 and the discharge temperature limit Tmax by a signal f ₁₁ expected, smaller (S5 (N) The processing returns to (S2) and the outdoor fan 14
Allow normal operation.

If it is large (S5 · Y), the correction frequency F _H for increasing the operation frequency of the outdoor fan 14 is set as follows in order to prevent the apparatus from being damaged by an increase in the high pressure due to the abnormal discharge temperature. (3) is calculated by equation and inputs the calculation signal f ₁₂ to the frequency command means 19 (S6).

[0028]

(Equation 2)

Next, by sending the current operating frequencies F ₁ of the outdoor fan 14 by the frequency command means 19, the signal f ₉ the frequency F ₂ plus correction frequency F _H as the operation frequency inverter control means 20 (S7), high operating the outdoor fan 14 as desired operation frequency F _2, and then returns to (S3).

In the same manner, the operation frequency of the outdoor fan 14 is controlled while predicting the next discharge temperature at the time T ₂ , T ₃ , T ₄ ,.

[0031] or more specifically shown by FIG. 3, during the operation of the operation for the wave number F ₁ between the outdoor fan 14 is a time T ₀ and T _1,
The discharge temperature rises due to a change in the outside air temperature, and at time T ₁ T _C 1
When the discharge temperature detecting means 17 detects T _{C 2} at time T ₂ , the detected temperature predicting means 21 calculates from the above equations (1) and (2)
Calculating a next discharge temperature T _C 3 at time T _3. Since this T _C 3 clearly smaller than the discharge temperature limit Tmax in Figure 3, the outdoor fan 14 is operated by conventional control.

At the next timing, the outside air temperature changes and the discharge temperature detecting means 17 changes the discharge temperature to T _C 2 and T ₃ at time T _2.
When T _C 3 is detected by the following equation, the detected temperature predicting means 21
(1), (2), and calculates the discharge temperature T _C 4 at time T _4. Since this T _C 4 is clearly larger than the discharge temperature upper limit Tmax, at the time T ₄ , the discharge temperature T _C draws a locus indicated by a broken line in the drawing, and it is predicted that an abnormal discharge temperature occurs.

Therefore, in order to avoid an abnormal discharge temperature, the following equation is used.
From (3), the correction frequency F _H for increasing the operating frequency of the outdoor fan 14 is calculated from the discharge temperature _TC 4 and the discharge temperature upper limit Tmax, and is output to the frequency command means 19.

Thus, the frequency command means 19 requests the inverter control means 20 for the operation frequency F ₂ to cause the outdoor fan 14 to operate at the operation frequency F _{2 obtained} by adding the correction frequency F _H to the current operation frequency F _1. Then, the outdoor fan 14 is turned on at time T _3.
Was changed in stages to the operating frequency F _2, a locus shown by the solid line at time T _4, it is possible to control the discharge temperature T _C without overshooting with respect to the discharge temperature limit Tmax. That is, the air conditioner can be operated at the full discharge temperature upper limit Tmax.

As described above, according to the present invention, if the next discharge temperature predicted by the detected temperature predicting means 21 during operation exceeds the upper limit value Tmax, the detected temperature determining means 18 sends the correction frequency to the frequency commanding means 19. The input is used to change the operating frequency of the outdoor fan to a high value. Therefore, the discharge temperature upper limit value Tmax can be set to the limit so that the capacity of the device can be fully utilized, the frequency of turning on and off the outdoor fan and the compressor can be significantly reduced, and the air conditioning state can be suppressed by suppressing uneven cooling. Of the indoor heat exchanger 3 can be prevented, and power consumption can be reduced.

[0036]

As described above, according to the air conditioner of the present invention, when the next discharge temperature predicted by the detected temperature prediction means during the operation of the compressor exceeds the upper limit value Tmax, the detected temperature determination means sets the correction frequency. Is input to the frequency command means to increase the operating frequency of the outdoor fan. The upper limit value Tmax of the discharge temperature can be set up to the capacity limit so that the capacity of the device can be sufficiently utilized. The frequency of turning on and off the machine is greatly reduced, and uneven air conditioning is suppressed, the air-conditioning state is maintained comfortably, and the power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of an air-conditioning control device according to an embodiment of the present invention.

FIG. 2 is an operation flowchart illustrating FIG. 1;

FIG. 3 is a characteristic diagram illustrating the operation of FIG.

FIG. 4 is a block diagram of an example of a conventional air conditioning control device.

FIG. 5 is a flowchart illustrating the operation of FIG. 4;

FIG. 6 is a characteristic diagram illustrating the operation of FIG.

[Explanation of symbols]

1 ... compressor, 2 ... four-way valve, 3 ... indoor heat exchanger, 4
... decompression device, 5 ... outdoor heat exchanger, 6 ... indoor unit, 7
... Operation command means, 8 ... Indoor unit control means, 9 ... Indoor fan, 10 ... Outdoor unit, 11 ... Outdoor unit control means, 12 ... Compressor electromagnetic switch, 13 ... Commercial AC power supply, 14 ... Outdoor fan, 16 ... Discharge temperature sensor, 17: discharge temperature detecting means, 18: detected temperature determining means, 19: frequency command means,
20: inverter control means, 21: detected temperature prediction means.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F24F 11/02 102 F25B 1/00 371 F25B 1/00 381

Claims (1)

(57) [Claims] In an air conditioner for controlling an operation frequency of an outdoor fan by an inverter, a discharge temperature detecting means for discharging the outdoor fan and a next discharge from a previous and a current discharge temperature detected by the discharge temperature detecting means. A correction frequency for correcting the operation frequency of the outdoor fan is calculated from the detected temperature prediction means for predicting the temperature, the discharge temperature detected last time and the current time, and the upper limit value of the discharge temperature, and the frequency of the inverter control means is calculated. Detection temperature determination means for outputting the correction frequency to the command means, and when the next discharge temperature predicted by the detection temperature prediction means exceeds the upper limit of the device capacity, the correction frequency calculated by the detection temperature determination means An air conditioner wherein the operating frequency of the outdoor fan is corrected to be higher.