JP3599861B2 - Air conditioner protection device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a protection device for an air conditioner, and more particularly, to a protection device for a compressor and a condenser incorporated in the air conditioner.
[0002]
[Prior art]
Generally, a compressor of an air conditioner is provided with a motor winding overheat protection device and a high-pressure switch.
[0003]
The overheating protection device for the motor winding of the compressor includes a protection device based on a control program stored in the control device, and a mechanical protection device such as a thermostat built in the compressor.
[0004]
The protection means according to the control program alternatively detects the temperature of the motor winding (the protection temperature value is, for example, 110 ° C.) by the temperature detection means such as a thermistor attached to the refrigerant discharge pipe of the compressor, based on the refrigerant discharge temperature. The detected temperature is compared with a preset refrigerant discharge temperature reference value (for example, 103 ° C.), and if the detected temperature exceeds the refrigerant discharge temperature reference value (for example, 103 ° C.), the compressor motor winding is overheated. Then, the compressor is stopped based on the protection control program stored in the control device (microcomputer or the like).
[0005]
Here, the reason why the refrigerant discharge temperature reference value (103 ° C.) is set lower than the motor winding temperature protection value 110 ° C.) is to allow for heat loss in the heat transfer path to the installation position of the temperature detecting means. Because it is.
[0006]
As the mechanical protection means, a thermostat incorporated in the compressor is used. When the winding temperature of the compressor exceeds a reference value, the thermostat operates to electrically connect the power supply circuit of the compressor. The contact of an electromagnetic contactor or the like inserted in the opening is opened to cut off the supply of power to the compressor.
The high-pressure switch is activated when the pressure in the compressor exceeds a predetermined pressure (for example, 28.5 kgw / cm ² ), and is electrically inserted into the power circuit of the compressor. A contact such as an electromagnetic contactor opens to cut off the supply of power to the compressor.
[0007]
Alternatively, the pressure of the condenser is detected as a condensing temperature (a protection value is, for example, 68 ° C.) corresponding to the pressure (28.5 kg / cm ² ), and the detected temperature is set to a preset condensing temperature reference value. When the pressure exceeds (for example, 64 ° C.), it is considered that the pressure of the condenser has become an abnormal pressure (26 kg / cm ² ), and control is performed to stop the compressor based on a protection control program stored in the control device. I do.
[0008]
In the above protection device, the protection operation of the protection means and the mechanical protection means by the control program is performed in any of the protection devices. The power is directly shut off by the means.
[0009]
[Problems to be solved by the invention]
Meanwhile, in the overheat protection device for the compressor motor winding of the air conditioner, the mechanical protection of the motor winding operates at a temperature (for example, 100 ° C.) lower than a preset refrigerant discharge temperature reference value (for example, 103 ° C.). In some cases, the compressor is stopped or an alarm is generated frequently. This is due to variations in the characteristics of the temperature detector itself such as a thermistor, the state of attachment, and the like.
[0010]
An object of the present invention is to provide a learning function that can prevent random operation of the protection device due to variations in the characteristics of the temperature detector and the like, and can automatically correct a deviation between the reference temperature and the detection sensitivity of the temperature detector. To provide a protective device.
[0011]
[Means for Solving the Invention]
According to the first aspect of the present invention, the refrigerant discharge temperature of the compressor is detected by a temperature detector attached to the refrigerant discharge pipe of the compressor, and the detected temperature becomes higher than a predetermined reference temperature. Air having first protection control means for stopping the operation of the compressor when the internal temperature of the compressor exceeds a predetermined temperature, and second protection control means for stopping supply of power to the compressor when the internal temperature of the compressor exceeds a predetermined temperature. In the protection device of the harmony device, when the second protection control means operates a predetermined number of times or more in a state where the first protection control means does not operate, the reference discharge temperature data of the first protection means is reset to a value lower by a predetermined value. It comprises a reference value updating means for setting.
[0012]
According to the first aspect of the present invention, when the second protection control means of the compressor has been operated a predetermined number of times or more in a state where the first protection control means is not operating, the reference value updating means detects the detection of the temperature detector. Assuming that the temperature contains an error, the reference temperature data is lowered by a predetermined value and reset so as to conform to the characteristic unique to the temperature sensor. In this way, by providing a learning function for updating the protection reference value in accordance with the characteristics of the actual temperature detector, it is possible to prevent mechanical protection (or alarm) operation from occurring randomly, and to perform inspection and protection control of the temperature detector. Work such as changing programs is labor-saving.
[0013]
According to a second aspect of the present invention, when the condensation temperature of the refrigerant is detected by a temperature detector attached to the condenser, the operation of the compressor is performed when the detected temperature becomes higher than a predetermined reference temperature. A first protection control means for stopping the compressor, and a third protection control means for stopping supply of power to the compressor when the internal pressure of the compressor exceeds a predetermined pressure. A reference value updating means for resetting the reference temperature data of the first protection means to a value lower by a predetermined value when the third protection control means is operated a predetermined number of times or more in a state where the first protection control means is not operated; It is comprised including.
[0014]
According to the second aspect of the present invention, when the third protection control means operates a predetermined number of times or more in a state where the first protection control means does not operate, the reference value updating means has an error in the temperature detected by the temperature detector. Is included, and the reference temperature data is lowered by a predetermined value and reset in order to conform to the characteristic unique to the temperature sensor. As described above, by providing a learning function for updating the protection reference value in accordance with the characteristics of the actual temperature detector, it is possible to prevent mechanical protection (or alarm) operation from being disturbed, to inspect the temperature detector, and to perform pressure condensation. Work such as changing the protection control program of the container can be saved.
[0015]
According to a third aspect of the present invention, the refrigerant discharge temperature of the compressor is detected by a temperature detector attached to a refrigerant discharge side pipe of the compressor, and the detected temperature becomes higher than a predetermined reference temperature. A first protection control unit for stopping the operation of the compressor when the internal temperature of the compressor exceeds a predetermined temperature, a second protection control unit for stopping supply of power to the compressor when the internal temperature of the compressor exceeds a predetermined temperature, A third protection control means for stopping supply of power to the compressor when the internal pressure of the compressor exceeds a predetermined pressure, wherein the first protection control means does not operate, A reference value for resetting the reference temperature data of the first protection means to a value lower by a predetermined value when the second protection control means has been operated more than a predetermined number of times, or when the third protection control means has been operated more than a predetermined number of times. Change Configured with the means.
[0016]
According to the third aspect of the present invention, the reference value updating means detects the temperature of the temperature detector when the second or third protection control means operates a predetermined number of times or more in a state where the first protection control means does not operate. Assuming that the temperature contains an error, the reference temperature data is lowered by a predetermined value and reset so as to conform to the characteristic unique to the temperature sensor. As described above, by providing a learning function for updating the protection reference value in accordance with the characteristics of the actual temperature detector, it is possible to prevent mechanical protection (or alarm) operation from being disturbed, to inspect the temperature detector, and to perform pressure condensation. Work such as changing the protection control program of the container can be saved.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a preferred embodiment of the present invention will be described with reference to the drawings.
[0018]
(I) Outline of air conditioner FIGS. 1 and 2 show an outline of an air conditioner according to the present invention.
[0019]
The air conditioner 1 includes an indoor unit 2 and an outdoor unit 3.
[0020]
The indoor unit 2 is provided with an indoor heat exchanger 4 that functions as an evaporator during a cooling operation and as a condenser during a heating operation, and an electric mechanical valve (electrically operated expansion valve) 8.
[0021]
The outdoor unit 3 includes a refrigerant compressor 5, an outdoor heat exchanger 7 that functions as a condenser during cooling operation and also functions as an evaporator during heating operation, and a solid line state during cooling and a broken line state during heating, respectively. The set four-way valve 50 is connected with a refrigerant pipe.
[0022]
During cooling, the refrigerant discharged from the compressor 5 flows in the direction of the solid arrow, and during heating, flows in the direction opposite to the arrow.
[0023]
(II) Protection device The compressor 5 of the air conditioner 1 is provided with a motor winding overheat protection device and a high-pressure switch 14. The overheating protection device for the motor winding of the compressor 5 includes a protection device based on a control program and a mechanical protection device using a thermostat or the like.
[0024]
The protection means based on the control program of the motor winding protection device of the compressor 5 includes a temperature sensor 9 such as a thermistor installed in the discharge pipe 5a of the compressor 5 for detecting a discharge temperature, and a temperature sensor 9 according to the protection control program. A control device such as a microcomputer for comparing the temperature signal with a predetermined reference discharge temperature and outputting a command to stop the compressor 5 when the detected discharge temperature reaches the reference discharge temperature. This protection control program is stored in a storage device in the control device 10 and is executed under the overall control of a CPU (central processing unit).
[0025]
The mechanical protection means of the motor winding protection device of the compressor 5 is such that the bimetal 12 installed near the motor winding inside the compressor 5 is interposed in the power supply circuit, and the motor winding is set at a set temperature (protection value = 110). ° C), the power supply drive circuit 13 is shut off to prevent the motor winding of the compressor 5 from burning.
[0026]
In the motor winding protection device of the compressor 5 described above, the protection operation of the protection means and the mechanical protection means by the control program is performed by first operating the protection means by the control program. The power is directly shut off by the means.
[0027]
When the internal pressure of the compressor 5 reaches a preset reference pressure (for example, 28.5 kgw / cm ² ), the high pressure switch 14 is activated, and the power supply drive circuit 13 is shut off to turn off the compressor. 5 prevents the motor winding from being burned out.
[0028]
Reference numeral 51 denotes a temperature sensor attached to the outdoor heat exchanger, which operates only during cooling to detect the condensation temperature of the refrigerant. Reference numeral 52 denotes a temperature sensor attached to the indoor heat exchanger, which operates only during heating to detect the condensation temperature of the refrigerant. These detected values are all input to the control device 10.
[0029]
(III) Learning function Next, the learning function of the protection device according to the present invention will be described.
[0030]
In this learning function, the reference discharge temperature set in the control device 10 is matched with the actual output signal value (sensitivity) of the temperature sensor 9 due to variations in the characteristics of the temperature sensor 9 itself, the state of attachment, and the like. If not, it will automatically calibrate. That is, if the mechanical protection means is operated a plurality of times (for example, three times) or more before the protection operation by the protection control program, the sensitivity of the temperature sensor 9 is determined to be low, and the reference set value is reduced by a predetermined temperature. The correction is made on software.
[0031]
FIG. 2 shows an example of a learning function algorithm when the bimetal 12 operates. In FIG. 2, td1 is an initial discharge temperature reference value (eg, 105 ° C.), td is a discharge temperature reference value (eg, 105 ° C.), and ti is a protection value of the compressor motor winding (eg, 110 ° C.). is there.
[0032]
In step 100, an initial value tdi of the discharge temperature reference value is set as the discharge temperature reference value td. Next, the routine proceeds to step 101, where it is determined whether or not the bimetal 12, which is the mechanical protection means, has been activated a predetermined number of times (a plurality of times, for example, three times). If NO in step 101, the process returns to continue the count operation. If the result of determination in step 101 is YES, control proceeds to step 102. In step 102, the correction value n (for example, 1 ° C.) is subtracted from the discharge temperature reference value td so far to update the discharge temperature reference value td. That is, td (NEW) = td (OLD) −n
The following control is performed using the discharge temperature reference value td (NEW) which is suitable for the current situation. In the same manner, the operation state of the protection device is constantly monitored in step 101, and learning is sequentially performed so as to conform to the current state. Therefore, a temporal change of the sensors and a temporal change of the mounting member are automatically followed, so that appropriate protection can always be performed.
[0033]
FIG. 3 shows an example of a learning function algorithm when the high-voltage switch 14 operates. In this example, the compressor 5 is protected by a condensing temperature corresponding to the pressure of the high-pressure switch 14 (a value detected by the temperature sensor 51 during cooling, and a value detected by the temperature sensor 52 during heating). It is.
In FIG. 3, tc1 is an initial value of the condensation temperature reference value (eg, 64 ° C.), tc is a condensation temperature reference value (eg, 64 ° C.), and th is a saturation temperature (eg, 68 ° C.) with respect to the high-pressure switch operating pressure. .
[0034]
In step 200, an initial value tci of the condensation temperature reference value is set as the condensation temperature reference value tc. Next, the routine proceeds to step 201, where it is determined whether or not the high-voltage switch, which is a mechanical protection means, has been operated a set number of times (a plurality of times, for example, three times). In step 201, if the determination is NO, the process returns and the counting operation is continued. If the result of determination in step 201 is YES, control proceeds to step 202. In step 202, a new temperature reference value tc (NEW) is updated by subtracting the correction value n (for example, 1 ° C.) from the previous condensation temperature reference value tc (OLD). That is, tc (NEW) = tc (OLD) −n
The following control is performed using the discharge temperature reference value tc (NEW) that is compatible with the current situation. In the same manner, the operation state of the protection device is constantly monitored in step 201, and learning is sequentially performed so as to conform to the current state. Therefore, a temporal change of the sensors and a temporal change of the mounting member are automatically followed, so that appropriate protection can always be performed.
[0035]
In the above-described embodiment, an example of the learning function algorithm when the bimetal 12 operates and an example of the learning function algorithm when the high-voltage switch 14 operates are separately shown. However, both learning functions are combined. It is also within the scope of the present invention to update the discharge temperature reference value when one of the bimetal 12 and the high-voltage switch 14 has operated a predetermined number of times or more.
[0036]
【The invention's effect】
As described above, according to the first to third aspects of the present invention, by providing a learning function of updating the protection reference value in accordance with the characteristics of the actual temperature detector, mechanical protection (or alarm) operation is performed. Work such as checking the temperature detector, changing the protection control program for the compressor motor winding, and the like is prevented, thereby preventing the occurrence of random occurrence.
[Brief description of the drawings]
FIG. 1 is a pipeline diagram of an air conditioner to which a protection device according to the present invention is applied.
FIG. 2 is a flowchart illustrating a learning control algorithm of a protection reference value of a compressor motor winding according to the present invention.
FIG. 3 is a flowchart illustrating a learning control algorithm of a protection reference value of the condenser according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Indoor unit 3 Outdoor unit 4 Indoor heat exchanger 5 Compressor 5a Discharge pipe 7 Outdoor heat exchanger 8 Expansion valve 9 Temperature sensor 10 Controller 12 Bimetal 13 Power supply drive circuit 14 High voltage switch 51 Temperature sensor (outdoor heat) (Exchanger side)
52 Temperature sensor (indoor heat exchanger side)
td1 Initial value of discharge temperature reference value td Discharge temperature reference value ti Protection value of compressor motor winding tc1 Initial value of condensing temperature reference value tc Condensing temperature reference value th Saturation temperature for high pressure switch operating pressure

Claims (3)

The refrigerant discharge temperature of the compressor is detected by a temperature detector attached to the refrigerant discharge side pipe of the compressor, and when the detected temperature becomes higher than a predetermined reference temperature, the operation of the compressor is stopped. A first protection control unit for causing the compressor to stop supplying power to the compressor when an internal temperature of the compressor exceeds a predetermined temperature.
A reference value updating means for resetting the reference discharge temperature data of the first protection means to a value lower by a predetermined value when the second protection control means has operated a predetermined number of times or more in a state where the first protection control means is not operating; A protection device for an air conditioner, comprising: A first protection control means for detecting the condensation temperature of the refrigerant by a temperature detector attached to the condenser, and stopping the operation of the compressor when the detected temperature becomes higher than a predetermined reference temperature. And a third protection control means for stopping supply of power to the compressor when an internal pressure of the compressor exceeds a predetermined pressure.
A reference value updating means for resetting the reference temperature data of the first protection means to a value lower by a predetermined value when the third protection control means is operated a predetermined number of times or more in a state where the first protection control means is not operated; A protection device for an air conditioner, comprising: The refrigerant discharge temperature of the compressor is detected by a temperature detector attached to the refrigerant discharge side pipe of the compressor, and when the detected temperature becomes higher than a predetermined reference temperature, the operation of the compressor is stopped. First protection control means for causing the compressor to stop supplying power to the compressor when the internal temperature of the compressor exceeds a predetermined temperature, and first protection control means for stopping the supply of power to the compressor when the internal temperature of the compressor exceeds a predetermined temperature. And a third protection control means for stopping the supply of power to the compressor when the
In a state where the first protection control means does not operate, when the second protection control means has been operated more than a predetermined number of times, or when the third protection control means has been operated more than a predetermined number of times, the reference temperature data of the first protection means is And a reference value updating means for resetting the reference value to a value lower by a predetermined value.

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