Compressor and control method for outlet temperature of compressor

Abstract

The invention provides a compressor and a control method for the outlet temperature of the compressor. The compressor comprises a host module, an oil-gas separator, a cooling module, a power module and a control unit. The host module is provided with an air inlet, an oil inlet and a medium outlet. The oil-gas separator is provided with a separator inlet, a separator gas outlet and a separator oil outlet. And the separator inlet is communicated with the medium outlet. The cooling module comprises an oil cooler and a fan, and the oil cooler is connected with the oil outlet and the oil inlet of the separator. The fan is used for cooling the oil cooler so as to control the outlet temperature of the medium outlet. The power module is connected with the host module and the fan. The control unit is in signal connection with the fan and is provided with a fuzzy logic algorithm, and the fuzzy logic algorithm is used for controlling the rotating speed of the fan based on the input power and the output air quantity at the air outlet of the separator. The number of parts is small, and the structure is simple. Meanwhile, the rotating speed of the fan is controlled through the power module and the control unit to adjust the outlet temperature.

Description

Technical Field

[0001] The present application relates to the field of compressors, and in particular to a compressor and a method for controlling the outlet temperature of the compressor. Background Art

[0002] As people's living standards continue to improve, many different types of compressors have appeared on the market. Compressors include positive displacement compressors, reciprocating compressors, screw compressors, etc. Screw compressors are sprayed with an appropriate amount of oil into the main engine of the screw compressor, which has the effect of cooling and sealing, thereby improving the energy efficiency of the compressor. Too high or too low oil temperature will bring additional power consumption. Only when the oil temperature is at the right temperature can the compressor be most efficient.

[0003] Existing screw compressors control the exhaust temperature of the compressor main engine by setting a temperature control valve and a constant-speed fan. However, regardless of the temperature or load, the fan always runs at a constant speed, the fan power consumption is high, the efficiency of the main engine is not at the highest point, and the temperature control valve is set, the compressor cost is high. At the same time, the existing screw compressor is equipped with a temperature control valve and a variable-speed fan. When the ambient temperature is low, the fan power is low and more energy-saving, but when the temperature control valve is half-open, the fan still wastes some power, and the efficiency of the main engine is not at the highest point. When some units of the compressor are under low load, there is a risk of oil emulsification in the oil medium of the compressor.

[0004] Therefore, it is necessary to provide an improved compressor and a method for controlling the compressor outlet temperature to solve the above problems. Summary of the invention

[0005] The present application provides a compressor with a simple structure, low cost and high working efficiency and a method for controlling the outlet temperature of the compressor.

[0006] The present application provides a compressor, comprising: a host module, provided with an air inlet, an oil inlet and a medium outlet; an oil-gas separator, provided with a separator inlet, a separator air outlet and a separator oil outlet, the separator inlet is communicated with the medium outlet, and the separated air and oil are respectively output from the separator air outlet and the separator oil outlet; a cooling module, comprising an oil cooler and a fan, the oil cooler is respectively connected to the separator oil outlet and the oil inlet, and the fan is used to cool the oil cooler to control the oil temperature of the oil inlet and the outlet temperature of the medium outlet; a power module, connected to the host module and the fan, to detect the input power of the compressor in real time; and a control unit, connected to the fan signal, the control unit is provided with a fuzzy logic algorithm, and the fuzzy logic algorithm is used to control the rotation speed of the fan based on the input power and the output gas volume at the separator air outlet.

[0007] Furthermore, a flow meter is provided at the separator gas outlet, and the flow meter is signal-connected to the control unit.

[0008] Furthermore, a variable speed motor is provided between the fan and the power module, and the control unit controls the rotation speed of the fan based on the detection value of the flow meter and the input power.

[0009] Furthermore, a first temperature sensor, a first pressure sensor and a humidity sensor are provided at the air inlet, and the first temperature sensor, the first pressure sensor and the humidity sensor are all signal-connected to the control unit to transmit their measured values ​​to the control unit.

[0010] Furthermore, a second temperature sensor and a second pressure sensor are provided between the medium outlet and the separator inlet, and the second temperature sensor and the second pressure sensor are signal-connected to the control unit to transmit their measured values ​​to the control unit.

[0011] Furthermore, an exhaust pressure sensor is provided at the separator outlet, and the exhaust pressure sensor is signal-connected to the control unit to transmit its measured value to the control unit.

[0012] Furthermore, the host module includes a host and a motor, and the motor is connected to the host and the power module for driving the host.

[0013] The present application also provides a method for controlling the outlet temperature of a compressor, wherein the compressor includes: a host module, an oil-gas separator, a power module and a fan, and the control method includes the following steps: obtaining the input power of the compressor, the actual outlet temperature of the medium outlet of the host module and the output gas volume of the separator outlet of the oil-gas separator; calculating the specific power in real time based on the input power and the output gas volume; obtaining the target outlet temperature based on the change of the specific power and a fuzzy logic algorithm; and controlling the rotation speed of the fan according to the target outlet temperature so that the actual outlet temperature is close to the target outlet temperature.

[0014] Furthermore, when the system pressure of the compressor is stable, the input power of the compressor, the actual outlet temperature of the medium outlet of the host module and the output gas volume of the separator outlet of the oil-gas separator are obtained to detect whether the system pressure of the compressor is stable, including the following steps: obtaining the actual exhaust pressure of the separator outlet; based on the target exhaust pressure of the separator outlet, calculating the absolute value of the difference between the actual exhaust pressure and the target exhaust pressure; if the absolute value of the difference is less than or equal to a set threshold, the system pressure of the compressor is stable; if the absolute value of the difference is greater than the set threshold, the system pressure of the compressor is unstable.

[0015] Furthermore, based on the change of the specific power and a fuzzy logic algorithm, a target outlet temperature is obtained, including the following steps: obtaining the ambient temperature of the air inlet of the host module, the ambient humidity and the outlet pressure of the medium outlet; calculating the dew point temperature based on the ambient temperature, the ambient humidity and the outlet pressure; calculating the calculated outlet temperature of the medium outlet through a fuzzy algorithm based on the specific power; and obtaining the target outlet temperature based on the calculated outlet temperature and the dew point temperature.

[0016] Furthermore, based on the calculated outlet temperature and the dew point temperature, obtaining the target outlet temperature also includes the following steps: if the calculated outlet temperature is greater than the dew point temperature, the target outlet temperature is the calculated outlet temperature; if the calculated outlet temperature is less than or equal to the dew point temperature, the target outlet temperature is the dew point temperature.

[0017] The compressor of the present application includes: a host module, an oil-gas separator, a cooling module, a power module and a control unit, with a small number of parts, a simple structure and low manufacturing cost. At the same time, the power module detects the input power of the compressor in real time, and the control unit controls the speed of the fan based on the input power and output gas volume through a fuzzy logic algorithm, adjusts the outlet temperature at the outlet of the medium, and improves the working efficiency of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a working schematic diagram of the compressor of the present application.

[0019] Figure 2 It is a main flow chart of the method for controlling the compressor outlet temperature of the present application.

[0020] Figure 3 It is a flow chart of the method for controlling the compressor outlet temperature of the present application.

[0021] Figure 4 yes Figure 3 The specific flow chart of step S100 of the method for controlling the compressor outlet temperature is shown.

[0022] Figure 5 yes Figure 3 The specific flow chart of step S400 of the method for controlling the compressor outlet temperature is shown.

[0023] Description of Figure Numbers:

[0024] 10. Host module; 11. Air inlet; 12. Oil inlet; 13. Medium outlet; 14. Host; 15. Motor; 20. Oil-oil separator; 21. Separator inlet; 22. Separator air outlet; 23. Separator oil outlet; 30. Cooling module; 31. Oil cooler; 32. Fan; 33. Variable speed motor; 40. Power module; 50. Control unit; 60. Flow meter; 71. First temperature sensor; 72. First pressure sensor; 73. Humidity sensor; 81. Second temperature sensor; 82. Second pressure sensor; 90. Exhaust pressure sensor. DETAILED DESCRIPTION

[0025] Here, the technical solutions in the embodiments (or "implementations") of the present application will be described clearly and completely in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0026] If there are terms involving directional indications or positional relationships in the embodiments of the present application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings); if the specific posture changes, the directional indication or positional relationship will also change accordingly. In addition, the terms "first", "second", etc. involved in the embodiments of the present application are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance.

[0027] See also Figure 1 As shown, the compressor includes a host module 10, an oil-gas separator 20, a cooling module 30, a power module 40, a control unit 50 and a flow meter 60. The host module 10 is connected to the oil-gas separator 20. The cooling module 30 is connected to the oil-gas separator 20 and the host module 10. The power module 40 is connected to the cooling module 30, the host module 10 and the control unit 50. The flow meter 60 is connected to the oil-gas separator 20.

[0028] The host module 10 is provided with an air inlet 11, an oil inlet 12 and a medium outlet 13. Gas enters the host module 10 from the air inlet 11, and oil medium enters the host module 10 from the oil inlet 12. The oil medium and gas are compressed in the compression chamber of the host module 10 to form an oil-gas mixture. The oil-gas mixture is output from the medium outlet 13 and then enters the oil-gas separator 20.

[0029] The host module 10 includes a host 14 and a motor 15, the host 14 is electrically connected to the motor 15, and the motor 15 is used to drive the host 14 to work. The air inlet 11, the oil inlet 12 and the medium outlet 13 are arranged around the host 14. The host 14 is the core component of the compressor, and the compressor compresses air through the host 14. The host 14 is connected to the oil-gas separator 20 through a pipeline. The medium outlet 13 is arranged on the pipeline between the host 14 and the oil-gas separator 20.

[0030] According to the implementation of the present application, a frequency converter may be provided on the motor 15 , and the frequency converter is connected to the motor 15 . The frequency converter can adjust the rotation speed of the motor 15 according to the pressure fluctuation in the host 14 to adjust the rotation speed of the host 14 .

[0031] The oil-gas separator 20 is provided with a separator inlet 21, a separator air outlet 22 and a separator oil outlet 23. The separator inlet 21 is connected to the medium outlet 13, and the oil-gas mixture enters the oil-gas separator 20 from the separator inlet 21 to separate the oil and gas. The separated air and oil are output from the separator air outlet 22 and the separator oil outlet 23 respectively.

[0032] The cooling module 30 includes an oil cooler 31, a fan 32 and a variable speed motor 33. The fan 32 rotates and cools the oil cooler 31. The variable speed motor 33 is connected to the fan 32 to control the rotation speed of the fan 32. The oil cooler 31 is connected to the oil-gas separator 20 and the main unit 14 respectively. The oil medium in the oil-gas separator 20 flows out from the separator oil outlet 23 and then flows into the oil cooler 31. The fan 32 cools the oil medium in the oil cooler 31, and then the oil medium in the oil cooler 31 is sprayed into the main unit 14 through the oil inlet 12. The oil medium has a cooling and sealing effect to improve the energy efficiency of the compressor. The fan 32 adjusts the oil temperature of the oil cooler 31 to control the oil temperature of the oil inlet 12 and the outlet temperature of the medium outlet 13.

[0033] The power module 40 is connected to the motor 15 and the variable speed motor 33. The power module 40 detects the input power of the compressor in real time, that is, the total power consumed by the compressor.

[0034] The control unit 50 is signal-connected to the power module 40. The control unit 50 is provided with a fuzzy logic algorithm for controlling the rotation speed of the fan 32 based on the input power of the compressor and the output air volume at the separator outlet 22.

[0035] The flow meter 60 is arranged at the separator outlet 22. The flow meter 60 detects the output gas volume at the separator outlet 22. The flow meter 60 is connected to the control unit 50 signal to transmit the measured output gas volume value to the control unit 50. Based on the input power and output gas volume of the compressor, the specific power of the compressor can be calculated. The specific power is an important performance index of the compressor, which indicates the total power required by the compressor for each cubic meter of compressed air produced. Based on the calculated specific power, the control unit 50 controls the outlet temperature at the medium outlet 13 to a suitable point by controlling the speed of the fan 32, so that the specific power of the compressor is the highest and the efficiency of the host 14 is the highest.

[0036] According to the embodiment of the present application, the flow meter 60 may not be provided. The output gas volume of the compressor is calculated according to the model and rotation speed of the compressor.

[0037] The first temperature sensor 71, the first pressure sensor 72 and the humidity sensor 73 are arranged at the air inlet 11. The first temperature sensor 71 is used to detect the intake air temperature at the air inlet 11. The first pressure sensor 72 is used to detect the inlet pressure at the air inlet 11. The humidity sensor 73 is used to detect the intake air humidity at the air inlet 11. The first temperature sensor 71, the first pressure sensor 72 and the humidity sensor 73 are all connected to the control unit 50 by signals, so as to output the measured values ​​of the intake air temperature, inlet pressure and intake air humidity to the control unit 50.

[0038] The second temperature sensor 81 and the second pressure sensor 82 are disposed between the medium outlet 13 and the separator inlet 21. The second temperature sensor 81 is used to measure the outlet temperature at the medium outlet 13. The second pressure sensor 82 is used to measure the outlet pressure at the medium outlet 13. The second temperature sensor 81 and the second pressure sensor 82 are connected to the control unit 50 by signals to output the measured values ​​of the outlet temperature and the outlet pressure to the control unit 50.

[0039] The exhaust pressure sensor 90 is disposed at the separator outlet 22. The exhaust pressure sensor 90 is used to measure the exhaust pressure at the separator outlet 22. The exhaust pressure sensor 90 is connected to the control unit 50 by signal so as to output the measured value of the exhaust pressure to the control unit 50.

[0040] See also Figures 2 to 5 As shown, the present application also provides a method for controlling the compressor outlet temperature, which is applicable to the above-mentioned compressor. The control method comprises the following steps:

[0041] S100: Detect the system pressure of the compressor;

[0042] S200: Acquire the input power of the compressor, the actual outlet temperature of the medium outlet 13 of the host module 10, and the output gas volume of the separator outlet 22 of the oil-gas separator 20;

[0043] S300: Real-time calculation of specific power based on input power and output gas volume;

[0044] S400: obtaining a target outlet temperature based on a change in specific power and a fuzzy logic algorithm;

[0045] S500: Control the rotation speed of the fan 32 according to the target outlet temperature so that the actual outlet temperature approaches the target outlet temperature.

[0046] In S100, when the system pressure of the compressor is stable, step S200 is performed. Detecting the system pressure of the compressor includes the following steps:

[0047] S101: Obtaining the actual exhaust pressure of the separator outlet 22;

[0048] S102 : Based on the target exhaust pressure at the separator outlet 22 , the absolute value of the difference between the actual exhaust pressure and the target exhaust pressure is calculated.

[0049] S103: If the absolute value of the difference is less than or equal to the set threshold, the system pressure of the compressor is stable, and the input power, actual outlet temperature and output gas volume can be obtained, and S200 is continued. If the absolute value of the difference is greater than the set threshold, the system pressure of the compressor is unstable, and S101 is re-executed to obtain the actual exhaust pressure of the separator outlet 22 until the absolute value of the difference is less than or equal to the set threshold.

[0050] In S101 , the actual exhaust pressure is measured and read by the exhaust pressure sensor 90 .

[0051] In the implementation manner of the present application, the threshold is set to 0.1 bar. In addition, other thresholds may be selected according to actual conditions.

[0052] In the implementation manner of the present application, in S101, to detect whether the system pressure of the compressor is stable, it is necessary to continuously obtain the actual exhaust pressure of the separator outlet 22 within a certain period of time, and the certain period of time may be 40 seconds to 60 seconds.

[0053] In S200, the input power of the compressor is detected and obtained by the power module 40. The actual outlet temperature of the medium outlet 13 is detected and obtained by the second temperature sensor 81. The output gas volume of the separator outlet 22 of the oil-gas separator 20 can be detected and obtained by the flow meter 60, or calculated according to the model and speed of the compressor.

[0054] In S400, based on the change of specific power and fuzzy logic algorithm, the target outlet temperature is obtained, which specifically includes the following steps:

[0055] S401: Acquire the ambient temperature and humidity of the air inlet 11 of the host module 10 and the outlet pressure of the medium outlet 13;

[0056] S402: Calculate the dew point temperature based on the ambient temperature, ambient humidity and outlet pressure;

[0057] S403: Based on the specific power, the calculated outlet temperature of the medium outlet 13 is calculated by a fuzzy algorithm;

[0058] S404: Obtain the target outlet temperature based on the calculated outlet temperature and the dew point temperature.

[0059] In S401 , the ambient temperature and ambient humidity of the air inlet 11 are detected and obtained by the first temperature sensor 71 and the humidity sensor 73 .

[0060] In S404, based on the calculated outlet temperature and the dew point temperature, the target outlet temperature is obtained, which also includes the following steps:

[0061] If the calculated outlet temperature is greater than the dew point temperature, the target outlet temperature is the calculated outlet temperature; if the calculated outlet temperature is less than or equal to the dew point temperature, the target outlet temperature is the dew point temperature.

[0062] The value of the target outlet temperature is always greater than the dew point temperature, which can avoid emulsification of the oil medium at the medium outlet 13 and improve the use efficiency of the oil in the compressor.

[0063] In the implementation manner of the present application, the control unit 50 can be externally connected to the client, and transmit the data of the specific power change to the client in real time to remind the client of the change in the specific power.

[0064] The compressor of the present application includes: a host module 10, an oil-gas separator 20, a cooling module 30, a power module 40 and a control unit 50, with a small number of parts, a simple structure and low manufacturing cost. At the same time, the power module 40 detects the input power of the compressor in real time, and the control unit 50 controls the speed of the fan 32 based on the input power and the output gas volume through a fuzzy logic algorithm, adjusts the outlet temperature at the medium outlet 13, improves the working efficiency of the compressor, and makes the specific power of the compressor at the highest point.

[0065] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without causing conflicts. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the drawings; all modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A compressor, characterized in that: include: The host module is provided with an air inlet, an oil inlet and a medium outlet; The oil-gas separator is provided with a separator inlet, a separator air outlet and a separator oil outlet, the separator inlet is communicated with the medium outlet, and the separated air and oil are respectively output from the separator air outlet and the separator oil outlet; A cooling module, comprising an oil cooler and a fan, wherein the oil cooler is connected to the oil outlet and the oil inlet of the separator respectively, and the fan is used to cool the oil cooler to control the oil temperature of the oil inlet and the outlet temperature of the medium outlet; A power module, connected to the host module and the fan, to detect the input power of the compressor in real time; and A control unit is connected to the fan signal, and the control unit is provided with a fuzzy logic algorithm, and the fuzzy logic algorithm is used to control the rotation speed of the fan based on the input power and the output air volume at the separator outlet.

2. The compressor according to claim 1, characterized in that The separator gas outlet is provided with a flow meter, and the flow meter is connected to the control unit by signal.

3. The compressor according to claim 2, characterized in that A variable speed motor is provided between the fan and the power module, and the control unit controls the rotation speed of the fan based on the detection value of the flow meter and the input power.

4. The compressor according to claim 1, characterized in that A first temperature sensor, a first pressure sensor and a humidity sensor are provided at the air inlet. The first temperature sensor, the first pressure sensor and the humidity sensor are all connected to the control unit by signals so as to transmit their measured values ​​to the control unit.

5. The compressor according to claim 1, characterized in that A second temperature sensor and a second pressure sensor are provided between the medium outlet and the separator inlet. The second temperature sensor and the second pressure sensor are signal-connected to the control unit to transmit their measured values ​​to the control unit.

6. The compressor according to claim 1, characterized in that The separator outlet is provided with an exhaust pressure sensor, and the exhaust pressure sensor is signal-connected with the control unit to transmit its measured value to the control unit.

7. The compressor according to any one of claims 1 to 6, characterized in that: The host module includes a host and a motor, and the motor is connected to the host and the power module and is used to drive the host.

8. A method for controlling the outlet temperature of a compressor, the compressor comprising: The host module, the oil-gas separator, the power module and the fan are characterized in that the control method comprises the following steps: Obtaining the input power of the compressor, the actual outlet temperature of the medium outlet of the host module, and the output gas volume of the separator outlet of the oil-gas separator; Calculate specific power in real time based on the input power and the output gas volume; Based on the change of the specific power and the fuzzy logic algorithm, obtaining the target outlet temperature; The rotation speed of the fan is controlled according to the target outlet temperature so that the actual outlet temperature approaches the target outlet temperature.

9. The method for controlling the compressor outlet temperature according to claim 8, characterized in that: When the system pressure of the compressor is stable, the input power of the compressor, the actual outlet temperature of the medium outlet of the host module, and the output gas volume of the separator outlet of the oil-gas separator are obtained to detect whether the system pressure of the compressor is stable, including the following steps: Obtaining the actual exhaust pressure at the separator outlet; Based on the target exhaust pressure at the separator outlet, calculating the absolute value of the difference between the actual exhaust pressure and the target exhaust pressure; If the absolute value of the difference is less than or equal to a set threshold, the system pressure of the compressor is stable; If the absolute value of the difference is greater than the set threshold, the system pressure of the compressor is unstable.

10. The method for controlling the compressor outlet temperature according to claim 8, characterized in that: Based on the change of the specific power and the fuzzy logic algorithm, the target outlet temperature is obtained, including the following steps: Acquire the ambient temperature and humidity of the air inlet of the host module and the outlet pressure of the medium outlet; Calculating a dew point temperature based on the ambient temperature, the ambient humidity and the outlet pressure; Based on the specific power, calculating the calculated outlet temperature of the medium outlet by a fuzzy algorithm; A target outlet temperature is obtained based on the calculated outlet temperature and the dew point temperature.

11. The method for controlling the compressor outlet temperature according to claim 10, characterized in that: Based on the calculated outlet temperature and the dew point temperature, obtaining the target outlet temperature further includes the following steps: If the calculated outlet temperature is greater than the dew point temperature, the target outlet temperature is the calculated outlet temperature; If the calculated outlet temperature is less than or equal to the dew point temperature, the target outlet temperature is the dew point temperature.

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