JP2002277022A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability and safety of an air conditioner by preventing the temperature of a rotational speed controller from rising even if an enormous current happens to flow simultaneously with high outdoor temperature. SOLUTION: The air conditioner comprises a refrigeration cycle constituted by connecting by piping an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve, and an indoor unit having an indoor expansion valve and an indoor heat exchanger with each other. The air conditioner further comprises a blower 2 connected to a power source 9 through the rotational speed controller 1 so as to variably control the rotational speed thereof, a temperature detector 6 for detecting outdoor temperature and a bypass circuit 10 connecting the power source 9 to the blower 2 with bypassing the controller 1. When the outdoor temperature detected by the detector 6 is a first limiting temperature or higher, the connection of the blower 2 is switched from the controller 1 to the bypass circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a blower whose rotation speed is controlled, and is particularly suitable for an air conditioner in which the rotation speed of an outdoor fan is variable.

[0002]

2. Description of the Related Art Conventionally, it has been known that an outdoor fan is driven by an inverter in accordance with the outdoor air temperature and the number of revolutions thereof is made variable. Japanese Patent Application Laid-Open No. H11-218352 describes that the rotation speed of the fan motor is reduced when the temperature of the heating element of the outdoor fan drive system is equal to or higher than a predetermined temperature.

[0003]

Conventionally, in controlling the rotation speed of the blower and the outdoor fan, the high pressure increases when the outside air temperature is high in the cooling operation. Therefore, the rotation speed of the blower is increased to suppress the high pressure. . In the above-mentioned prior art, the fan drive system, the outdoor heat exchanger, the refrigerant pipe and the like are prevented from being overheated and damaged.

However, when the outside air temperature becomes high,
Since the rotation speed of the outdoor fan is high, a large current flows through the rotation speed control device. Therefore, when the two factors, that is, the high outside air temperature and the large current flow, overlap, the temperature of the rotation speed control device increases, and the life of the rotation speed control device tends to be shortened.

An object of the present invention is to solve the above-mentioned problems of the prior art, improve the reliability and safety of the air conditioner, and avoid forcibly stopping the air conditioner.

[0006]

In order to achieve the above object, the present invention comprises an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve, an indoor expansion valve and an indoor heat exchanger. Air conditioner equipped with a refrigeration cycle connected by pipes to an indoor unit that has been connected to a power supply via a rotation speed control device, and a blower whose rotation speed is variably controlled, and a temperature detector that detects the outside air temperature And a bypass circuit connected to the blower by bypassing the rotation speed control device from the power supply. When the outside air temperature detected by the temperature detector is equal to or higher than the first limit temperature, the blower is controlled by the rotation speed control device. From the connection to the bypass circuit.

When the outside air temperature is equal to or higher than the first limit temperature, that is, when the outside air temperature is high, the rotation speed control device is bypassed, and no current flows through the rotation speed control device. There is no heat generation of the device, and there is no overlap between the fact that the outside air temperature is high and that a large current flows through the rotation speed control device. Therefore, there is no risk of failure due to overheating of the rotation speed control device, and the reliability and safety of the air conditioner can be improved.

Further, the present invention provides a refrigeration system in which an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve and an indoor unit having an indoor expansion valve and an indoor heat exchanger are connected by piping. In an air conditioner having a cycle, a blower connected to a power supply via a rotation speed control device and having a variable rotation speed and a bypass circuit connected to the blower by bypassing the rotation speed control device from the power supply. A current sensor that detects a current flowing through the rotation speed control device, and when the current detected by the current sensor is equal to or greater than the first limit current,
The connection of the blower is switched from the rotation speed control device to the bypass circuit.

Further, in the above, when the outside air temperature is lower than the first limit temperature, the blower is desirably driven by the rotation speed control device.

[0010] Further, in the above, the current is the first.
If the current is less than the limit current, it is desirable that the blower be driven by a rotation speed control device.

Further, in the above-described apparatus, it is desirable that the switching from the rotation speed control device of the blower to the bypass circuit is performed by a relay circuit having a relay coil and a relay contact.

Further, in the above, when the outside air temperature drops to a second limit temperature lower than the first limit temperature,
It is desirable that the blower is driven by a rotation speed control device.

Furthermore, in the above, the current is the first
When the current drops to the second limit current smaller than the limit current, the blower is desirably driven by the rotation speed control device.

Further, there is provided a refrigeration cycle in which an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve and an indoor unit having an indoor expansion valve and an indoor heat exchanger are connected by piping. The air conditioner includes a blower driven from a power supply via a rotation speed control device, and a current sensor for detecting a current flowing through the rotation speed control device, and when the detected current is determined to be abnormal, The blower is driven from a power supply by bypassing a rotation speed control device.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the conventional rotation speed control of an air conditioner, as shown in FIG. 2, power is supplied to the rotation speed control device 1 and the output voltage is varied by the rotation speed control device 1 based on transmission information from the control board 7. The number of rotations of the blower motor 2 (outdoor fan, indoor fan) is controlled via the blower condenser 3. Therefore, when the rotation speed increases,
As the load increases, a large current flows through the rotation speed control device 1, the components generate heat, and the temperature rises. Furthermore, when the outside air temperature increases, the rise in the outside air temperature is added to the heat generated by the components, which causes a failure of the rotation speed control device 1.

FIG. 1 shows a refrigeration cycle in which an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve and an indoor unit having an indoor expansion valve and an indoor heat exchanger are connected by piping. The blower motor 2 for driving the blower used in the air conditioner provided with the blower is connected to the power supply 9 via the rotation speed control device 1, the blower capacitor 3, and the current sensor 8, and the rotation speed is controlled. The voltage is varied by the control device 1 to control the rotation speed. The voltage is varied by transmitting a signal from the control board 7.

A bypass circuit 10 directly connected from the power supply 9 to the blower motor 2 by bypassing the rotation speed control device 1.
Is provided, and a relay contact 4 is provided so that the rotation speed control device 1 and the power supply 9 can be switched. The relay contact 4 can be switched by a relay coil 5 controlled by a control board 7. Further, the output of the current sensor 8 is input to the control board 7, and the control board 7 determines the magnitude of the value. Further, the control board 7
Has a temperature detector 6 such as a thermistor that detects the outside air temperature
Is connected to determine the magnitude of the outside air temperature.

As shown in the flowchart of FIG. 4, in the control board 7, when the outside air temperature is constantly detected by the temperature detector 6, and the temperature rises to the first limit temperature X ° C., the control board 7 is released. Applying a current to the coil 5; By switching the relay contact 4 to the power supply 9 side, the rotation speed control device 1 is bypassed, and the blower motor 2 is directly connected to the power supply 9 to operate at full speed. This means that the circuit has been changed so that no current flows through the rotation speed control device 1.

Next, when the temperature drops to the second limit temperature Y.degree. C., the power supply from the control board 7 to the relay coil 5 is cut off. Thereby, the relay contact 4 in FIG. 1 is switched from the power supply 9 to the rotation speed control device 1, and the rotation speed of the blower motor 2 is varied by the rotation speed control device 1. Limit temperature X,
Although Y may be equal, it is desirable to provide a hysteresis as shown in FIG. 5 in order to operate the relay contact 4 reliably.

As described above, when the outside air temperature is equal to or higher than the limit temperature X ° C., no current flows to the rotation speed control device 1 and heat generation of parts can be suppressed, and a rise in temperature can be prevented. (1) The reliability of the product can be improved without increasing the heat resistance. Further, when the temperature is equal to or lower than the second limit temperature Y ° C., the rotation speed control using the rotation speed control device 1 can be performed. be able to.

Further, the method shown in the flowchart of FIG. 6 will be described. In the control board 7, the current of the blower motor 2 is constantly detected by the current sensor 8, and when the current rises to the first limited current X amps, the control board 7 allows the current to flow to the relay coil 5. Then, by switching the contact 4 to the power supply 9 side, the rotation speed control device 1 is bypassed, and the blower motor 2 is directly connected to the power supply 9 to operate at full speed.

Next, when the current drops to the second limited current Y ampere, the control board 7 cuts off the current to the relay coil 5. Thereby, the relay contact 4 in FIG. 1 is switched from the power supply 9 to the rotation speed control device 1, and the blower motor 2
The rotation speed is varied by the rotation speed control device 1. Although the limiting currents X and Y may be equal, it is desirable to provide a hysteresis with an arbitrary temperature difference as shown in FIG.

As described above, since a current equal to or larger than the limited current X amps does not flow through the rotation speed control device 1, the reliability of the product can be improved without increasing the rated capacity of the rotation speed control device. In addition, when the current is equal to or less than the limited current Y amperes, the rotation speed control using the rotation speed control device 1 is enabled, so that the increase in the high pressure in the cooling operation can be suppressed and the reliability can be improved.

Further, the method shown in the flowchart of FIG. 8 will be described. In the control board 7, the current of the blower motor 2 is constantly detected by the current sensor 8, and the rotation speed control device 1,
When an abnormality occurs in the blower motor 2 and becomes equal to or less than the third limit current A ampere or equal to or more than the fourth limit current B ampere, the control board 7 causes the relay coil 5 to supply current.
Then, by switching the relay contact 4 to the power supply 9 side, the rotation speed control device 1 is bypassed and the blower motor 2 is directly connected to the power supply 9 for operation.

According to the above, when the outside air temperature becomes high, the rotation speed control device 1 is bypassed from the power supply 9, so that the rotation speed control device 1 itself does not generate heat and the temperature rise can be suppressed. Therefore, the rotation speed control device can be protected, and an air conditioner excellent in reliability and safety can be obtained. Further, since it is not necessary to increase the heat resistance of the rotation speed control device, the capacity and the like of the switching element used can be suppressed as much as possible. Furthermore, even when the rotation speed control device 1 malfunctions, the air conditioner can be prevented from being forcibly stopped, and can be operated continuously.

[0026]

According to the present invention, the high temperature of the outside air temperature and the flow of a large current do not overlap, and the temperature of the rotation speed control device does not rise. Safety and safety.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a blower driving device according to an embodiment.

FIG. 2 is a circuit diagram using a conventional rotation speed control device.

FIG. 3 is a block diagram of a control board unit that controls the relay and the like in FIG. 1;

FIG. 4 is a control flowchart according to one embodiment.

FIG. 5 is a diagram showing a relation between a limit temperature and on / off of a relay according to the embodiment;

FIG. 6 is a control flowchart according to another embodiment.

FIG. 7 is a diagram showing a relation between a limiting current and on / off of a relay according to another embodiment.

FIG. 8 is a control flowchart according to another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotation speed control device, 2 ... Blower motor, 4 ... Relay contact, 5 ... Relay coil, 7 ... Control board, 8 ... Current sensor.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yoshiki Hata 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Inside Hitachi Air Conditioning Systems Shimizu Production Headquarters (72) Inventor Kenichi Oishi 390 Muramatsu, Shimizu-shi Shizuoka Prefecture Hitachi Shimizu Engineering Co., Ltd. In-house F term (reference) 3L060 AA02 CC03 CC10 DD08 EE06

Claims (8)

[Claims] 1. A refrigeration cycle in which an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve and an indoor unit having an indoor expansion valve and an indoor heat exchanger are connected by piping. In the air conditioner, a fan connected to a power supply via a rotation speed control device, the rotation speed of which is controlled to be variable, a temperature detector for detecting an outside air temperature, and the power supply bypassing the rotation speed control device. And a bypass circuit connected to the blower, wherein when the outside air temperature detected by the temperature detector is equal to or higher than a first limit temperature, the connection of the blower is switched from the rotation speed control device to the bypass circuit. An air conditioner characterized by that: 2. A refrigeration cycle in which an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve and an indoor unit having an indoor expansion valve and an indoor heat exchanger are connected by piping. In the air conditioner, a blower connected to a power supply via a rotation speed control device, the rotation speed of which is controlled to be variable, a bypass circuit connected to the blower from the power supply bypassing the rotation speed control device, A current sensor for detecting a current flowing through the rotation speed control device, wherein when the current detected by the current sensor is equal to or greater than a first limit current, the blower is connected to the bypass circuit from the rotation speed control device. An air conditioner characterized by being switched. 3. The air conditioner according to claim 1, wherein the blower is driven by the rotation speed control device when the outside air temperature is lower than the first limit temperature. 4. The air conditioner according to claim 2, wherein when the current is less than the first limit current, the blower is driven by the rotation speed control device. 5. The switch according to claim 1, wherein the switching from the rotation speed control device of the blower to the bypass circuit is performed by a relay circuit having a relay coil and a relay contact. Air conditioner. 6. The air blower according to claim 1, wherein the blower is driven by the rotation speed control device when the outside air temperature falls to a second limit temperature lower than the first limit temperature. And air conditioner. 7. The blower according to claim 2, wherein the blower is driven by the rotation speed control device when the current drops to a second limit current smaller than the first limit current. Air conditioner. 8. A refrigeration cycle in which an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve and an indoor unit having an indoor expansion valve and an indoor heat exchanger are connected by piping. In an air conditioner, a blower driven from a power supply via a rotation speed control device,
A current sensor that detects a current flowing through the rotation speed control device, and when the detected current is determined to be abnormal, the blower is driven from the power supply bypassing the rotation speed control device. An air conditioner characterized by the following.