JPH05164382A - Air conditioner - Google Patents

Abstract

PURPOSE:To permit comfortable air conditioning, capable of developing an air-conditioning capacity sufficiently until the lower limit value of a suction temperature upon a low outside air temperature of cooling, which is set in an air-conditioning machine, in an air-conditioner in which the operating fre quency of an outdoor fan is controlled through inverter control. CONSTITUTION:An air conditioner is provided with a suction temperature detecting means 17 for the suction air of an outdoor fan 14, a detecting temperature estimating means 21, estimating the suction temperature of next time from the detected suction temperature of previous time and the same temperature of this time, and a detecting temperature deciding means 18, operating the corrected operating frequency of the outdoor fan 14 from the suction temperature and the lower limit value of the suction temperature, which are detected at a previous time and this time. When the suction temperature of next time, which is estimated by the detecting temperature estimating means 21, has exceeded a lower limit value of the suction temperature, the operating frequency of the outdoor fan 14 is corrected by the operated correcting frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner equipped with an inverter device 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) is often controlled by an inverter device that changes a power supply frequency. For example, the actual development Sho 61-1280
Japanese Patent Publication No. 55 discloses such an air conditioner.

FIG. 4 is a block diagram showing an example of a conventional air conditioning controller. In the figure, 1 is a compressor, 2 is a four-way valve,
Reference numeral 3 is an indoor heat exchanger, 4 is a decompression device, and 5 is an outdoor heat exchanger, and these are annularly connected by a pipe or the like to form a refrigerant cycle.

Reference numeral 6 designates an indoor unit, which turns on the air conditioner.
The operation command means 7 determines the off state, the indoor unit control means 8 determines the on / off of the indoor fan 9 according to the instruction of the operation instruction means 7, and the indoor fan 9.

Further, 10 is an outdoor unit, 11 is an outdoor unit control means,
Reference numeral 12 is an electromagnetic switch for a compressor, 13 is a commercial AC power source, 14 is an outdoor fan, and 15 is an electromagnetic switch for an outdoor fan. The indoor unit control unit 8 and the outdoor unit control unit 11 are activated by a command from the operation command unit 7 of the indoor unit 6, and control the electromagnetic switch 12 for the compressor to turn on / off the commercial AC power source 13 to turn on the compressor 1 The outdoor fan electromagnetic switch 15 is turned on / off to turn on / off the outdoor fan 14.

Reference numeral 16 is an intake temperature sensor attached to the low pressure portion of the compressor 1, the output of which is input to the intake temperature detecting means 17,
The detected intake temperature T _C is compared with the intake temperature lower limit value Tmin by the detected temperature determination means 18 and output to the outdoor unit control means 11 as control information.

The conventional air conditioner is configured as described above, FIG. 5 is a flowchart of its operation, and FIG. 6 is a diagram showing the operating characteristics of the outdoor fan 14, which will be described below with reference to these figures.

[0008] First, in step 1 in FIG. 5 (Note that hereinafter abbreviated steps as S), if the operation command means 7 is stopped repeatedly (S1), if the operating condition, chamber by the signal f ₁ The machine control means 8 turns on the indoor fan 9 to draw in air, and the operation f of the outdoor machine control means 11 is commanded to f.
_{Do 2} And accompanied not the outdoor unit control means 11 signals f _3, f ₄
This turns on the electromagnetic switch 12 for the compressor and the electromagnetic switch 15 for the outdoor fan to turn the commercial AC power supply 13 on to the outdoor fan 14.
To the equipment to bring the equipment into operation.

Next, in (S2), the outdoor unit control means 11 determines whether the operating state of the outdoor fan 14 should be turned on or off according to the air conditioning capacity of the device, and the electromagnetic noise for the outdoor fan is determined according to the determination signal f _4. The on / off operation of the switch 15 is performed to control the suction operation of the outdoor fan 14.

In (S3), the intake temperature detecting means 17 calculates the intake temperature T _C from the output f ₅ of the intake temperature sensor 16, and (S4)
Then, the intake temperature T _C detected by the intake temperature detecting means 17 is input to the detected temperature determining means 18 (f ₆ ), and the determination signal (f ₇ ) is output to the outdoor unit control means 11. The determination here returns when it is larger than the lower limit value Tmin of the intake temperature (S2), and the normal operation of controlling the outdoor fan 14 in accordance with the environmental temperature of the room or the like is performed.

If the intake temperature T _C is smaller than the above comparison, the intake temperature becomes abnormal and the indoor heat exchanger 2 is frozen due to a low pressure drop, and there is a risk that the device will stop functioning. In S5), in order to forcibly turn off the outdoor fan 14, the compressor electrode switch 12 is turned off by the signal f ₃ from the outdoor unit control means 11, and the process returns to (S3).

That is, in FIG. 6, times T ₀ to T ₁
During this period, the outdoor fan 14 is turned on to secure the capacity, and at time T ₁ , the intake temperature T _C drops due to changes in the outside air temperature, and when it falls below the intake temperature lower limit value Tmin, the outdoor heat exchanger 5 is forced to stop. To raise the suction temperature T _C.

Further, at time T ₂ , the intake temperature T _C becomes equal to or higher than the intake temperature lower limit value Tmin, so that the outdoor heat exchanger 5 is turned on again to secure the air conditioning capacity. This is time T ₃ and T ₄
Also in, the air conditioning can be performed by performing the same operation.

[0014]

However, in the above conventional air conditioning control, as shown in FIG. 6, the intake temperature lower limit value Tmin set in consideration of the overshoot amount δ of the intake temperature in the case of a low outdoor temperature of cooling is set high. There is a problem that the function of the device cannot be fully exerted because it needs to be set.

Further, since the outdoor fan 14 is frequently turned on and off, the air-conditioning capacity varies, and uneven cooling occurs.
The human body may be uncomfortable and the indoor heat exchanger 3 may freeze.

Further, when the suction temperature cannot be sufficiently raised only by controlling the outdoor fan 14, the compressor 1 is turned on / off, which has a drawback of increasing power consumption.

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

[0018]

According to the present invention, in an air conditioner for controlling the operating frequency of an outdoor fan by an inverter, the above-mentioned intake temperature detecting means for inhaling air by the outdoor fan and the intake temperature detecting means detect the same. Correction for correcting the operating frequency of the outdoor fan based on the detected temperature predicting means for predicting the next intake temperature from the previous and present intake temperatures, the intake temperature detected last time and this time, and the lower limit value of the intake temperature. A detection temperature determination unit that calculates a frequency and outputs the correction frequency to the frequency command unit of the inverter control unit is provided, and the next intake temperature predicted by the detection temperature prediction unit is the lower limit of the intake temperature at the outside temperature of the cooling room. When the value exceeds the value, the correction frequency calculated by the detected temperature determination means causes
It is characterized in that the operating frequency of the outdoor fan is corrected.

[0019]

According to the present invention, when the next predicted value of the intake temperature of the detected temperature predicting means becomes lower than the intake temperature lower limit value Tmin during the operation of the compressor, the detected temperature determining means 18 sets the correction frequency to the frequency. Since the operating frequency of the outdoor fan 14 is changed by inputting it to the command means 19, it is possible to set the intake temperature lower limit value Tmin of the cooling low outside air temperature to the limit of the device capacity, and therefore the device capacity can be fully utilized. At the same time, the frequency of turning on and off the outdoor fan 14 and the compressor 1 can be significantly reduced, and comfortable air conditioning for the human body can be performed, the freezing of the indoor heat exchanger 3 can be prevented, and It is possible to reduce power consumption.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings with reference to the accompanying drawings.

FIG. 1 is a block diagram of an air conditioner according to an embodiment of the present invention. Reference numerals 1 to 18 are the same as or have the same functions as in FIG. 4, and detailed description thereof will be omitted. In addition, 19 is a frequency command means for determining the operating frequency, 20 is an inverter control means, and 21 is an outdoor fan.
It is a detection temperature predicting means for predicting the next intake temperature from the intake temperature previously detected by 14 and the intake 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.

First, referring to FIG. 2, in (S1), if the operation command means 7 is instructing "stop" by the signal f _1, (S1) is repeated. When the machine control means 8 turns on the indoor fan 9, the outdoor machine control means 11 is instructed to operate f ₂ (S1). As a result, the outdoor unit control means 11 turns on the electromagnetic switch 12 for the compressor by the signal f ₃ , and supplies power from the commercial AC power supply 13 to the compressor 1.

Further, the outdoor unit control means 11 activates the operation of the frequency command means 19 by the signal f ₈ to determine the operating frequency of the outdoor fan 14 which satisfies the capacity required for the apparatus by the indoor temperature and the like, A command f ₉ is issued to the inverter control means 20 for the operating frequency information (S2).

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

Next, the intake temperature detection means 17 detects the intake temperature T _C of the air taken in by the outdoor fan 14 from the output f ₅ of the intake temperature sensor 16 (S3).

Next, the detection output f from the intake temperature detecting means 17
_{In the} detected temperature predicting means 21 by ₁₀ , the previous time T ₁
The intake temperature calculated in step S1 is T _C 1, and the intake temperature calculated at this time T ₂ is T _C 2, and the following general formula (1) and
(2) by calculating the intake temperature T _C 3 in the next time T ₃ (S4).

[0028]

[Equation 1]

Next, in the detected temperature judging means 18, the next intake temperature T _C 3 is compared with the intake temperature lower limit value Tmin by the signal f ₁₁ calculated and predicted by the detected temperature predicting means 21, and if it is larger (S5・ N) Processing returns to (S2) and outdoor fan 14
Causes normal operation.

If it is small (S5 · Y), an abnormality in the intake temperature is predicted, and in order to prevent the danger that the indoor heat exchanger 3 is frozen and the apparatus stops due to a low pressure drop, the outdoor fan 14
The correction frequency F _H for lowering the operating frequency is calculated by the following equation (3), and the calculated signal f ₁₂ is input to the frequency command means 19 (S6).

[0031]

[Equation 2]

Next, the frequency control means 19 sets the frequency F ₂ obtained by subtracting the above-mentioned correction frequency F _H from the current operation frequency F ₁ of the outdoor fan 14 as the operation frequency and the inverter control means 20.
By sending a signal f ₉ to (S7), driving the outdoor fan 14 as desired operation frequency F _2, and then returns to (S3).

Similarly, at times T ₂ , T ₃ , T ₄ , ..., The operating frequency of the outdoor fan 14 is controlled while predicting the next intake temperature according to the next intake temperature and the current intake temperature.

More specifically, referring to FIG. 3, the outdoor fan 14 is operating at the operating wave number F ₁ between times T ₀ and T ₁ ,
Suction temperature is T _C 1 at time T ₁ the outside air temperature is lowered, the suction temperature detecting means 17 a T _C 2 at time T _2, detects, detected temperature prediction unit 21 is the above formula (1) and ( 2), calculates the next intake temperature T _C 3 at time T _3. Since this T _C 3 is obviously larger than the lower limit value of intake temperature Tmin from FIG. 3,
The outdoor fan 14 is operated by normal control.

At the next timing, the outside air temperature changes and the intake temperature detecting means 17 detects the intake temperature, and at the time T ₂ , T _C 2, T ₃
When T _C 3 is detected by, the detected temperature prediction means 21
(1), (2) to calculate the intake temperature T _C 4 at time T _4. That is, in FIG. 3, since T _C 4 is smaller than the lower limit value Tmin of the intake temperature, at time T ₄ , the intake temperature T _C can be predicted to draw a broken line locus as shown in the figure, and an abnormality in the intake temperature can be predicted. ..

Therefore, in order to avoid the abnormal intake temperature,
From (3), the correction frequency F _H that lowers the operating frequency of the outdoor fan 14 is calculated from the intake temperature T _C 4 and the intake temperature lower limit value Tmin, and the calculated correction frequency F _H is output to the frequency command means 19.

Accordingly, the frequency command means 19 requests the inverter control means 20 to have the operating frequency F ₂ in order to operate the outdoor fan 14 at the operating frequency F _{2 obtained} by subtracting the correction frequency F _H from the current operating frequency F _1. Outdoor fan 14
The order to change the operation frequency F ₂ at the stage of the time T _3, draw a trajectory shown by the solid line at time T _4, the suction temperature lower limit value Tm
The suction temperature T _C can be controlled without overshooting in. That is, the air conditioner can be operated at the intake temperature lower limit value Tmin.

As described above, according to the present invention, when the next intake temperature predicted by the detected temperature predicting means 21 during operation falls below the lower limit value Tmin, the detected temperature determining means 18 sends the correction frequency to the frequency command means 19. It is input to change the operating frequency of the outdoor fan. Therefore, the lower limit value Tmin of the intake temperature at the time of cooling low outside temperature can be set to the limit so that the capacity of the device can be fully utilized, and the frequency of turning on / off the outdoor fan 14 and the compressor 1 can be greatly reduced. It is possible to suppress uneven cooling and maintain a comfortable air-conditioning state, prevent freezing of the indoor heat exchanger 3, and reduce power consumption of the device.

[0039]

As described above, in the air conditioner of the present invention, when the next intake temperature predicted by the detected temperature prediction means during the operation of the compressor exceeds the lower limit value Tmin, the detected temperature determination means corrects the correction frequency. Is input to the frequency commanding means to change the operating frequency of the outdoor fan, so that the lower limit value Tmin of the intake temperature at the time of cooling low outside air temperature can be set to the capacity limit so that the capacity of the device can be fully utilized. As a result, the frequency of turning on and off the outdoor fan and the compressor is greatly reduced, uneven cooling can be suppressed, and the air-conditioning state can be maintained comfortably. Moreover, freezing of the outdoor heat exchanger is prevented, and The power consumption can be reduced.

[Brief description of drawings]

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

FIG. 2 is an operation flowchart illustrating FIG.

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.

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 ... Intake temperature sensor, 17 ... Intake temperature detecting means, 18 ... Detected temperature determining means, 19 ... Frequency command means,
20 ... Inverter control means, 21 ... Detected temperature prediction means.

Claims (1)

[Claims] 1. An air conditioner in which an operating frequency of an outdoor fan is inverter-controlled, the above-mentioned intake temperature detecting means for sucking air by the outdoor fan, and the next and next intake temperatures detected by the intake temperature detecting means. The detected temperature predicting means for predicting the intake temperature of the outdoor fan, the intake temperature detected last time and the current time, and the lower limit value of the intake temperature, the correction frequency for correcting the operating frequency of the outdoor fan is calculated, and the inverter control means is calculated. When the next intake temperature predicted by the detected temperature predicting means exceeds the lower limit value of the intake temperature at the outside air temperature of the cooling, the detected temperature determining means for outputting the corrected frequency to the frequency command means An air conditioner characterized in that the operating frequency of the outdoor fan is corrected by the correction frequency calculated by the determination means.