CN108758970B - Abnormal state detection method of exhaust temperature sensing bulb and compressor protection method - Google Patents

Abstract

Hair brushThe invention discloses an abnormal state detection method of an exhaust temperature sensing bulb and a compressor protection method. The abnormal state detection method of the exhaust temperature sensing bulb judges whether the exhaust temperature sensing bulb is abnormal or not through the opening degree of the expansion valve; when the exhaust temperature sensing bulb is judged to be abnormal, the compressor protection method leads the compressor to be in accordance with a given initial opening degree P_SThe operation is continued and maintained at the initial opening degree. By adopting the abnormal state detection method of the exhaust gas temperature sensing bulb, the abnormal state of the exhaust gas temperature sensing bulb can be effectively detected. When the exhaust temperature sensing bulb is judged to be abnormal, the compressor protection method of the invention is adopted to provide refrigeration/heating output and enable the compressor to continue to operate, so that the air conditioner can continue to operate reliably without burning the compressor, and simultaneously, an alarm is given to a user to inform the user that the exhaust temperature sensing bulb is in fault and needs to be maintained in time.

Description

Abnormal state detection method of exhaust temperature sensing bulb and compressor protection method

Technical Field

The invention relates to a protection method of a compressor, in particular to a detection method based on an abnormal state of an exhaust temperature sensing bulb and a method for implementing corresponding protection measures on the compressor based on the result, and belongs to the technical field of sensing control.

Background

At present, the conventional sensors of the outdoor unit of the household air conditioner comprise 3 environment temperature sensing bags, an exhaust temperature sensing bag and an outer pipe temperature sensing bag, wherein the exhaust temperature sensing bag is mainly used for detecting exhaust temperature, the exhaust temperature is controlled by controlling the step number of an electronic expansion valve, and the exhaust temperature reaches a preset target value T_{d_target}However, if the detected exhaust temperature deviates from the actual exhaust temperature due to dropping or failure, the expansion valve may be closed all the time, and finally the actual exhaust temperature may be abnormally high and exceed the acceptable temperature of the compressor winding, thereby burning out the compressor.

The chinese patent application with application number CN201711062314.4 discloses a detection method of a compressor temperature sensor, which comprises the following steps: changing the running frequency of the compressor according to preset parameters in a first preset time period; acquiring the exhaust temperature of the compressor detected by the temperature sensor in a second preset time period; judging whether the exhaust temperature corresponds to the operating frequency of the compressor; if so, judging that the temperature sensor is normal; if not, judging that the temperature sensor is abnormal. The method determines whether the detected temperature sensor is abnormal by determining correspondence of the discharge temperature and the operating frequency of the compressor.

Disclosure of Invention

The invention provides a method for judging whether a temperature sensing bulb is abnormal or not through an opening degree of an expansion valve and a protection method of a compressor based on the method, aiming at solving the problem that when the detected exhaust temperature deviates from the actual exhaust temperature due to falling or faults and the like, the actual exhaust temperature is abnormally high due to abnormal closing of the expansion valve and the compressor is burnt out in the prior art.

The technical scheme of the invention is as follows:

the invention provides a method for detecting abnormal state of an exhaust temperature sensing bulb, which judges whether the exhaust temperature sensing bulb is abnormal or not through the opening degree of an expansion valve, and comprises the following steps:

step 1: after the compressor is started to operate, whether the expansion valve reaches the lower limit opening degree P is judged_{low_limit}And last for T₁Time, if yes, step 2 is carried out, if no, normal control is continued;

step 2: opening degree of expansion valve is switched to lower limit and lasts for T₁After the time, it is judged whether the exhaust temperature is satisfied (T)_d-T_{d_target})＜T_d1If yes, performing the step 3, otherwise, continuing to control normally;

wherein, T_dIs the actually measured exhaust temperature, T, of the current exhaust temperature sensing bulb_{d_target}Is the current target exhaust temperature value; t is_d1Is the theoretical minimum difference between the actual exhaust temperature and the target exhaust temperature when the opening degree is closed to the lower limit;

and step 3: and judging the abnormity of the exhaust temperature sensing bulb.

Further, the lower limit opening degree P_{low_limit}Including a lower limit opening degree P in a cooling mode_{C_low_limit}And a lower limit opening P in the heating mode_{H_low_limit}Namely:

a refrigeration mode:

heating mode:

where F is the currently operating compressor frequency, T_outerIs the current outdoor ambient temperature, T_innerIs the current indoor ambient temperature, parameter a_C、b_C、c_C、d_C、a_H、b_H、c_H、d_HX1, X2, X3 are constants fitted from experimental tests.

Further, said T₁The value range of (A) is 10-30 min.

Further, said T_d1The value range of (A) is-30-10 ℃.

The present invention also provides a compressor protection method, including the above-mentioned abnormal state detection method of the exhaust bulb, further including the following step 4 after the step 3:

when the exhaust temperature sensing bulb is judged to be abnormal, the compressor is started according to a given initial opening P_SContinuing to operate and keeping the initial opening unchanged;

the initial opening degree P_SIncluding an initial opening P in a cooling mode_{C_S}And an initial opening degree P in the heating mode_{H_S}Namely:

a refrigeration mode:

heating mode:

wherein F is the currently operating compressor frequency, T_outerIs the current outdoor ambient temperature, T_innerIs the current indoor ambient temperature, parameter a_{C_S}、b_{C_S}、c_{C_S}、d_{C_S}、a_{H_S}、b_{H_S}、c_{H_S}、d_{H_S}Are constants fitted from experimental tests.

Further, the step 4 further includes the following steps:

and sending an alarm to the internal machine to inform a user that the exhaust temperature sensing bulb is in failure and needs to be maintained in time.

The invention has the following beneficial effects:

by adopting the abnormal state detection method of the exhaust gas temperature sensing bulb, the abnormal state of the exhaust gas temperature sensing bulb can be effectively detected. When the exhaust temperature sensing bulb is judged to be abnormal, the compressor protection method of the invention is adopted to provide refrigeration/heating output, so that the air conditioner can continuously and reliably run without burning the compressor, and simultaneously, an alarm is given to a user to inform the user that the exhaust temperature sensing bulb is in fault and needs to be maintained in time.

Drawings

FIG. 1 is a general flow diagram of the compressor protection method of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The general flow of the compressor protection method of the present invention is shown in fig. 1, wherein the abnormal state detection method of the exhaust gas temperature sensing bulb of the present invention is included. The method comprises the following specific steps:

1. in the design stage of each prototype, the lower limit opening degree P of the electronic expansion valve capable of ensuring the reliability of the compressor can be determined through tests_{low_limit}The lower limit opening degree P_{low_limit}The corresponding system exhaust is the upper limit exhaust temperature which can be borne by the compressor, and the opening degree of the expansion valve is lower than the lower limit opening degree P for a long time_{low_limit}When the compressor is operated, the compressor is damaged, and the lower limit opening can be expressed by the following formula:

a refrigeration mode:

heating mode:

wherein: f represents the currently operating compressor frequency; t is_outerRepresenting the current outdoor side ambient temperature; t is_innerRepresenting the current indoor side ambient temperature; parameter a_C、b_C、c_C、d_C、a_H、b_H、c_H、d_HX1, X2, X3 are constant values, obtained by fitting according to experimental tests.

2. After the starting operation, if the exhaust temperature cannot reach the target exhaust temperature, the opening of the electronic expansion valve is closed all the time until the lower limit opening is closed, and T is continued₁Judging the exhaust temperature;

3. opening degree is closed to lower limit and T is continued₁After time, judge (T)_d－T_{d_target}) Size, if (T)_d－ T_{d_target})＜T_d1Then, the detected temperature value T of the exhaust temperature sensing bulb at the moment is judged_dIf there is an abnormality, the exhaust bulb detects the temperature value T_dCannot represent the actual exhaust temperature value, T_d1Is the theoretical minimum difference between the actual exhaust temperature and the target exhaust temperature when the opening degree is closed to the lower limit, and this parameter is established empirically, for example, in the range of (-30 ℃ to 10 ℃).

It should be noted that the lower limit opening is determined according to the limit exhaust temperature that the compressor can bear in the design stage, and it is generally considered that the exhaust temperature should be very high when the opening has been closed to the lower limit and is much larger than the current target exhaust, but if the detected temperature fed back by the exhaust bulb is not high and is a distance away from the target exhaust temperature, it can be determined that the temperature value detected by the exhaust bulb at this time is not the true exhaust temperature, and there is a possibility that the bulb gets loose or the bulb is damaged.

4. When the exhaust temperature sensing bulb detection value is judged to be abnormal, two operations are required to be executed at the moment: 1) sending an alarm to the internal machine to tell a user that the exhaust temperature sensing bulb is in failure and needs to be maintained in time; 2) the compressor continues to operate, but the opening is not controlled according to the discharge temperature, but according to a given initial opening P_SRunning and keeping the opening degree unchanged;

initial opening degree P_SCan be determined experimentally in the design stage, the calculation formula is as follows:

a refrigeration mode:

heating mode:

wherein: parameter a_{C_S}、b_{C_S}、c_{C_S}、d_{C_S}、a_{H_S}、b_{H_S}、c_{H_S}、d_{H_S}Is a constant value and is obtained by fitting according to experimental tests.

In the process of the invention, T₁The value is generally (10-30) min; t is_d1The value is generally (-30-10) DEG C; t is_dIndicating the current actual exhaust temperature, T, of the bulb_d-targetRepresenting the current exhaust temperature value.

In summary, the abnormal state detection method of the exhaust temperature sensing bulb of the present invention determines whether the exhaust temperature sensing bulb of the outdoor unit of the air conditioner is abnormal through the opening degree of the expansion valve, and when the exhaust temperature sensing bulb is determined to be abnormal, the compressor protection method of the present invention is adopted to provide the output of the cooling/heating amount to continue the operation of the compressor, so that the air conditioner can continue to operate reliably without burning out the compressor, and simultaneously, an alarm is given to a user to inform the user that the exhaust temperature sensing bulb is in failure and needs to be maintained in time.

The above-mentioned embodiments are only one embodiment and should not be construed as limiting the present invention. Various parameters in the specific using process can be adjusted according to actual requirements.

Claims (5)

1. An abnormal state detection method of an exhaust gas temperature sensing bulb, characterized in that: whether the exhaust temperature sensing bulb is abnormal or not is judged through the opening degree of the expansion valve, and the method comprises the following steps:

step 1: after the compressor is started to operate, whether the expansion valve reaches the lower limit opening degree P is judged_{low_limit}And last for T₁Time, if yes, step 2 is carried out, if no, normal control is continued;

step 2: opening degree of expansion valve is switched to lower limit and lasts for T₁After the time, it is judged whether the exhaust temperature is satisfied (T)_d-T_{d_target})＜T_d1If yes, performing the step 3, otherwise, continuing to control normally;

wherein, T_dIs the actually measured exhaust temperature, T, of the current exhaust temperature sensing bulb_{d_target}Is the current target exhaust temperature value; t is_d1Is the theoretical minimum difference between the actual exhaust temperature and the target exhaust temperature when the opening degree is closed to the lower limit;

and step 3: judging the exhaust temperature sensing bulb is abnormal;

the lower limit opening degree P_{low_limit}Including a lower limit opening degree P in a cooling mode_{C_low_limit}And a lower limit opening P in the heating mode_{H_low_limit}Namely:

a refrigeration mode:

heating mode:

where F is the currently operating compressor frequency, T_outerIs the current outdoor ambient temperature, T_innerIs the current indoor ambient temperature, parameter a_C、b_C、c_C、d_C、a_H、b_H、c_H、d_HX1, X2, X3 are constants fitted from experimental tests.

2. The method of detecting an abnormal state of an exhaust gas bulb according to claim 1, characterized in that: the T is₁The value range of (A) is 10-30 min.

3. The method of detecting an abnormal state of an exhaust gas bulb according to claim 1, characterized in that: the T is_d1The value range of (A) is-30-10 ℃.

4. A method of protecting a compressor, comprising: the abnormal state detection method including the exhaust gas bulb according to any one of claims 1 to 3, further including the following step 4 after the step 3:

when the exhaust temperature sensing bulb is judged to be abnormal, the compressor is started according to a given initial opening P_SContinuing to operate and keeping the initial opening unchanged;

the initial opening degree P_SIncluding an initial opening P in a cooling mode_{C_S}And an initial opening degree P in the heating mode_{H _S}Namely:

a refrigeration mode:

heating mode:

wherein F is the currently operating compressor frequency, T_outerIs the current outdoor ambient temperature, T_innerIs the current indoor ambient temperature, parameter a_{C_S}、b_{C_S}、c_{C_S}、d_{C_S}、a_{H_S}、b_{H_S}、c_{H_S}、d_{H_S}Are constants fitted from experimental tests.

5. A compressor protection method as claimed in claim 4, wherein: the step 4 further comprises the following steps:

and sending an alarm to the internal machine to inform a user that the exhaust temperature sensing bulb is in failure and needs to be maintained in time.

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