JPH0810084B2 - Operation control device for air conditioner - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device of an air conditioner in which a compressor is driven by an inverter, and more particularly to measures for preventing overheating of the inverter.

(Prior Art) Conventionally, as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 2-128020, as a structure of an electric parts case attached to an outdoor unit of an air conditioner, a front surface of a case body is opened, and this front surface is opened. A small gap is formed between the front lid that closes the opening and the upper lid that covers the upper surface of the case body, and a ventilation passage that flows inside and outside the case is formed from the upper end of the front lid to the lower end of the front surface of the upper lid. It is a known technique to prevent the electric parts inside from being heated by forming them.

(Problems to be Solved by the Invention) By the way, when the compressor driving inverter in which a high current flows is housed in the above-mentioned conventional electric part case, the electric parts are cooled by the outdoor fan. It can be effectively prevented.

On the other hand, during the cooling operation of the air conditioner, if the outside air temperature decreases, the outdoor fan may be stopped or operated at a low air volume in order to avoid excessive decrease in the condensation temperature. In the case where the cooling is performed by the blow of the outdoor fan, the inside of the electric parts case is not sufficiently cooled, and there is a fear that the inverter may overheat.

The present invention has been made in view of the above circumstances, and an object thereof is to anticipate a condition that causes overheating of an inverter, and under such a condition, provide a means for cooling an electric parts case housing the inverter. Therefore, it is possible to effectively prevent abnormal overheating of the inverter without causing any trouble on the refrigerant circuit side.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the means taken by the invention of claim (1) is, as shown in FIG. 1, an outdoor fan mounted on a casing (2) of an outdoor unit (1). The frequency of the outdoor heat exchanger (10) and the frequency of the compressor is stored in the ventilation path of the outdoor fan (18) that is formed from the air suction port of the casing (2) to the air outlet port of the casing (2). It is premised on an air conditioner in which an electric parts case (21) accommodating an inverter for adjustment is installed.

Then, as an operation control device of the air conditioner, a condensing temperature detecting means (Pr) for detecting the condensing temperature of the refrigerant, and an output of the condensing temperature detecting means (Pr) during cooling operation, and the condensing temperature is equal to or lower than a predetermined value. The air flow rate control means (50A) for controlling the outdoor fan (18) to stop at that time, and when the stopped state of the outdoor fan (18) by the air flow rate control means (50A) continues for a predetermined time or longer, the air flow rate control is performed. The means (50A) is forcibly stopped and the outdoor fan (18) is operated for a certain period of time by a forced operation means (51A).

The means taken by the invention of claim (2) is based on the same air conditioner as that of the invention of claim (1) above, and as an operation control device of the air conditioner, a condensation temperature detection for detecting the condensation temperature of the refrigerant. Means for controlling the outdoor fan (18) so that the outdoor fan (18) operates at a low air volume when the condensation temperature is below a predetermined value (Pr) and the output of the condensation temperature detecting means (Pr) during cooling operation. 50B) and the air volume control means (5
When the low air volume operation of the outdoor fan (18) by 0B) continues for a predetermined time or longer, the control of the air volume control means (50B) is forcibly stopped, and the outdoor fan (18) is set to the high air volume side for a certain period of time. The configuration is such that a forced operation means (50B) for switching operation is provided.

(Operation) With the above configuration, in the invention of claim (1), during cooling operation, if the condensation temperature of the refrigerant is lowered due to low outside air or the like and falls below a predetermined value, the outdoor unit is controlled by the air volume control means (50A). The outdoor fan (18) of the unit (1) is stopped to prevent the condensation temperature from excessively decreasing.

At that time, the inverter for frequency adjustment of the compressor (11) is housed in the electric part case (21) in the casing (2), and the inverter cooled by the air blow in the electric part case (21) is cooled. However, in the present invention, when the outdoor fan (18) remains stopped for a predetermined time, the forced operation means (51A) forcibly controls the air volume control means (50A). The fan (18) is controlled so that it is stopped and the fan (18) is operated for a certain period of time.
The air blow of 8) is circulated and abnormal overheating of the inverter is prevented.

According to the invention of claim (2), during cooling operation, when the condensation temperature of the refrigerant is lowered due to low outside air or the like and falls below a predetermined value,
The outdoor fan (18) of the outdoor unit (1) is switched to a low air volume by the air volume control means (50B), but when the low air volume operation of the outdoor fan (18) continues for a predetermined time, the forced operation means (51B) , The control of the air volume control means (50B) is forcibly stopped, and the fan (18) is controlled to operate by switching to the high air volume side for a certain period of time. The amount of air blown by the fan (18) increases, and abnormal overheating of the inverter is prevented.

(Embodiment) Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows the structure of the outdoor unit (1) of the air conditioner. The outdoor unit (3) is housed in the casing (2) of the outdoor unit (1) and the casing (2) is used. ) Is a floor plate (4), a top plate (5), and a plurality of side plates (7a)
~ (7c) and a protective net (8). The floor plate (4) is a rectangular plate material that forms the bottom of the outdoor unit (1), and a mounting flange (4a) is provided upright on the periphery of the floor plate (4). (7c)
Are installed upright on the mounting flange (4a) which is installed upright on the outer peripheral portion of the floor plate (4) in three directions by means of screws or the like.

Further, the protective net (8) is attached to one side of the attachment flange (4a) of the floor plate (4) excluding three sides to which the side plates (7a) to (7c) are attached,
The outside air can be introduced into the outdoor unit (1). The top plate (5) serves as a lid of a box body formed by the side plates (7) and the protective net (8), and has a ventilation outlet (6) at the center thereof. The outlet (6) is provided with a protective wire net (6a) for preventing foreign matter from entering the outdoor unit (3).

Next, the inside of the outdoor unit (3) is provided with a heat exchanger (10) formed in a substantially U-shape in a plane so as to face the protective net (8). The floor plate (4) has a compressor (1
1), an accumulator (12) and a receiver (13) are attached to the respective devices (10), (11), (12), (1)
The refrigerant pipes (14) are connected to each other by a refrigerant pipe (14) to form a part of a refrigeration circuit, and the refrigerant pipe (14) extends to the indoor unit side. Then, the compressor (11) in the refrigerant pipe (14)
A pressure sensor (Pr) is attached to the discharge pipe as a condensing temperature detecting means for detecting a high-pressure side pressure converted into a condensation temperature equivalent saturation temperature high-pressure side pressure. A fan mount (16) is installed on the outdoor unit (1), and a fan (18) rotatable by a driving force of a motor (17) is supported on the fan mount (16). There is. The fan (18) is of a variable air volume type capable of switching between a standard air volume "H" and a low air volume "L".

Here, of the three side plates (7a) to (7c), the side plate (7c) on the side facing the protective net (8) is divided into an upper plate (7c1) and a lower plate (7c2). Upper plate (7c1)
An electric parts case (21) for accommodating electric parts (P) such as an inverter is attached to the. As shown in FIG. 3 and FIG. 4, the electric parts case (21) has an opening in the front surface of a case body (22) for accommodating the electric parts (P), and a front lid body that closes the front opening. (twenty three)
And an upper lid (24) for covering the upper surface side of the case body (22). An upper gap (25) is formed between the front lid (23) and the upper end of the case body (22), and the lower end of the case body (22) and one end of the lower end of the front lid (23) are connected to each other. A lower gap (26) is formed between the lower gap (26) and the upper gap (2) during operation of the fan (18).
Ventilation air circulates inside and outside the case over 5).

Here, an opening (7d) that connects the inside and the outside of the outdoor unit (1) is provided at a portion of the upper plate (7c1) to which the electric part case (21) is attached and that faces the lower gap (26). Is provided, and outside air (Wo) from the opening (7d) passes through the lower gap (26), and the electric parts case (2
1) It is designed to flow inside.

In the vicinity of the lower gap (26), (27) is a shield plate for shielding internal air (Wi) after heat exchange that flows inside the outdoor unit (1), and (28) is a clamp plate (29). The air thermistor is attached to the case body (22) via the to detect the outside air temperature.

Next, air volume control of the fan (18) of the outdoor unit (1) will be described with reference to the flowchart of FIG. First, in step ST1, it is determined whether or not the cooling operation is performed,
If it is a cooling operation, it proceeds to step ST2 to determine whether it is thermo-on. If it is thermo-on, it proceeds to step ST3, and the saturation temperature Tc of the refrigerant equivalent to the condensation pressure detected by the pressure sensor (Pr) is Determine whether it is lower than 19.0 ℃. Then, the saturation temperature Tc equivalent to the condensation pressure is determined by this determination.
If it is 19.0 ° C or higher, then the normal cooling operation is performed. That is, in step ST4, it is determined whether Tc <30 ° C. and Tc ≧ 30.
If the temperature is ℃, the fan (18) air volume is set to a high air volume "H" in step ST5, and if Tc <30 ℃, the fan (1) is flown (1
8) Reduce the air volume to "L" and perform cooling operation.

On the other hand, when the condensation temperature equivalent to the condensation temperature Tc of the refrigerant is reduced due to low outside air and Tc <19 ° C. in the determination in step ST3 above, the process proceeds to step ST7 in order to avoid excessive reduction of the condensation pressure equivalent saturation temperature Tc. After shifting, it is determined whether or not the 30-minute timer described later has timed up. If not, the fan (18) is stopped in step ST8, and then in step ST9
While setting the minute timer (or counting when the timer is operating), if the 30-minute timer times out in the judgment of step ST7, that is, the condensation pressure equivalent saturation temperature Tc
If the temperature is lower than 19.0 ° C for 30 minutes, the process proceeds to step ST10 to prevent overheating of the electric parts (P) due to long-time fan (18) stoppage, and the 3-minute timer described later times up. Until step ST11, fan (18)
After operating with low air volume "L", in step 12,
The three-minute timer is set (or the timer counts while the timer is operating), and the process returns to step ST1.

If it is determined in step ST1 that the heating operation is not the cooling operation, the process proceeds to step ST13, and if the thermostat is on, the fan (18) air volume is set to the standard air volume "H" in step ST14 while the thermostat is turned off. Sometimes step
Move to ST15 and stop fan (18). Further, in the determination of step ST2, even when the thermostat is turned off during the cooling operation, the process proceeds to step ST15 and the fan (18) is stopped.

In the above flow, the control of step ST8 receives the output of the pressure sensor (condensing temperature detecting means) (Pr) during the cooling operation, and stops the outdoor fan (18) when the condensing temperature Tc is equal to or lower than the predetermined value. Air volume control means to control (50
A) is configured, and when the outdoor fan (18) is stopped by the air volume control means (50A) for a predetermined time or longer by the control of step ST11, the air volume control means (50A)
The forced operation means (51A) is configured to forcibly stop the control of (1) and operate the outdoor fan (18) for a certain period of time.

Therefore, in the above-described embodiment, during cooling operation, when the condensation pressure equivalent saturation temperature Tc of the refrigerant decreases due to low outside air or the like and drops below a predetermined value (19.0 ° C. in the above-described embodiment), the air volume control means (50A) causes Fan (1) of the outdoor unit (1)
8) is stopped, and the excessive decrease of the saturation pressure equivalent saturation temperature Tc is prevented.

At that time, the casing (2) of the outdoor unit (1)
The electric parts case (21) housed inside has a compressor (1
The inverter for frequency adjustment of 1) is stored (electrical part (P) in the above embodiment), and the electric part case (21) is always installed in the ventilation passage of the fan (18),
Although it is cooled by the air blow, it is cooled by the fan (1
If 8) stops, there is a risk that the inverter will overheat due to the stop of cooling. At that time, if the stopped state of the fan (18) continues for a predetermined time (30 minutes in the above embodiment), the forced operation means (51A) forcibly stops the control of the air volume control means (50A), and Since (18) is operated for a fixed time (3 minutes in the above embodiment), the air blown by the fan (18) flows through the electric parts case (21) to effectively prevent abnormal overheating of the inverter. Will be done. Also in that case, since the fan (18) is operated after the fan (18) is stopped for a predetermined time, the condensation pressure equivalent saturation temperature Tc is drastically excessively lowered by the operation of the fan (18). There is no fear of this occurring, and there is no adverse effect on the refrigerant circuit side.

Further, in the above embodiment, when the saturation temperature Tc corresponding to the condensation pressure is excessively lowered, the fan (1
8) is stopped, but the present invention is not limited to such an embodiment, and for example, the fan (18) may have a low air flow rate "L" (or a low air flow rate "LL" depending on the type of the fan (18). , Etc.) can also be applied to those that are switched. That is, even when the fan (18) is operated at a low air volume "L" for a long time, the inverter may be overheated. In that case, the control of step ST8 in the flowchart of FIG. 5 is performed. Is operated at low air volume "L", and its control is air volume control means (50B), and the control of step ST11 is performed by operating the fan (18) at high air volume "H". By using the forced operation means (51B), it is possible to obtain the same effect as that of the above embodiment.

(Effect of the invention) As described above, according to the invention of claim (1),
Condensing the refrigerant as an operation control device for an air conditioner in which a ventilation path for an outdoor fan is formed in the casing of the outdoor unit, and an electric parts case containing an outdoor heat exchanger and an inverter is installed in this ventilation path. When the temperature drops below a specified value, the outdoor fan is stopped and
When the outdoor fan is stopped for a predetermined period of time, the outdoor fan is operated only for a certain period of time, so the inverter housed in the electric parts case can be cooled, thus improving reliability. be able to.

According to the invention of claim (2), as the operation control device of the air conditioner, the outdoor fan is operated at a low air volume when the condensing temperature of the refrigerant is lower than a predetermined value, and the outdoor fan is operated at a low air volume. When it is continued for a predetermined time, the outdoor fan is switched to the high air volume side for a certain time to operate, so that the inverter housed in the electric parts case can be cooled, thus improving reliability. be able to.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of the present invention. 1 and the following shows an embodiment of the present invention, FIG. 2 is an exploded perspective view showing the structure of an outdoor unit, and FIG. 3 is a sectional view taken along line III-III of FIG. 4 showing a sectional structure of an electric parts case. FIG. 4 is a front view of the electric parts case, and FIG. 5 is a flowchart showing the contents of fan air volume control. 1 …… Outdoor unit 2 …… Casing 10 …… Heat exchanger (outdoor heat exchanger) 18 …… Fan (outdoor fan) 21 …… Electrical parts case 50 …… Air volume control means 51 …… Forced operation means P… … Electrical parts Pr …… Pressure sensor (condensing temperature detection means)

Claims (2)

[Claims] 1. A casing (2) of an outdoor unit (1)
The outdoor fan (18) is housed in the casing (2).
An electric parts case (21) for accommodating the outdoor heat exchanger (10) and an inverter for adjusting the frequency of the compressor is provided in the ventilation path of the outdoor fan (18) formed from the air suction port to the air outlet of the compressor. ) Is installed in the air conditioner, the condensation temperature detecting means (Pr) for detecting the condensation temperature of the refrigerant,
During cooling operation, receiving the output of the condensation temperature detecting means (Pr),
The air volume control means (50A) for controlling the outdoor fan (18) to stop when the condensing temperature is equal to or lower than a predetermined value, and the stop state of the outdoor fan (18) by the air volume control means (50A) continues for a predetermined time or more. Then, the air flow control means (50
Forcibly stop the control of (A), and use the outdoor fan (1
8) An operation control device for an air conditioner, comprising: a forced operation means (51A) for operating the air conditioner for a predetermined time. 2. A casing (2) of an outdoor unit (1)
The outdoor fan (18) is housed in the casing (2).
An electric parts case (21) for accommodating the outdoor heat exchanger (10) and an inverter for adjusting the frequency of the compressor is provided in the ventilation path of the outdoor fan (18) formed from the air suction port to the air outlet of the compressor. ) Is installed in the air conditioner, the condensation temperature detecting means (Pr) for detecting the condensation temperature of the refrigerant,
During cooling operation, receiving the output of the condensation temperature detecting means (Pr),
The outdoor fan (18) when the condensing temperature is below the specified value
Air volume control means (50
B) and the outdoor fan (18) by the air volume control means (50B)
When the low air volume operation of (1) continues for a predetermined time or longer, the control of the air volume control means (50B) is forcibly stopped, and the outdoor fan (18) is switched to the high air volume side for a certain period of time to operate the forced air operation means ( 50B) and an operation control device for an air conditioner.