CN111520895B - Control method of condensing fan and refrigerating unit - Google Patents

Control method of condensing fan and refrigerating unit Download PDF

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Publication number
CN111520895B
CN111520895B CN202010357462.4A CN202010357462A CN111520895B CN 111520895 B CN111520895 B CN 111520895B CN 202010357462 A CN202010357462 A CN 202010357462A CN 111520895 B CN111520895 B CN 111520895B
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suction pressure
pressure control
exhaust pressure
condensing fan
controlling
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CN111520895A (en
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杨虹
卫广穹
张正
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/87—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling absorption or discharge of heat in outdoor units
    • F24F11/871—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling absorption or discharge of heat in outdoor units by controlling outdoor fans
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F24F11/64—Electronic processing using pre-stored data
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2140/00—Control inputs relating to system states
    • F24F2140/10—Pressure

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Thermal Sciences (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

The invention discloses a control method of a condensing fan and a refrigerating unit. The control method of the condensing fan comprises the following steps: monitoring the discharge pressure and the suction pressure; and controlling the frequency of the condensing fan according to the relation between the exhaust pressure and the exhaust pressure control range and by combining the relation between the suction pressure and the suction pressure control range. When the frequency of the condensing fan is controlled, the exhaust pressure and the suction pressure of the compressor are simultaneously referred to, the matching of the rotating speed of the condensing fan and a condensing load is ensured, the low-pressure is kept stable, and the reliability of a unit is ensured.

Description

Control method of condensing fan and refrigerating unit
Technical Field
The invention relates to a control method of a condensing fan, in particular to a frequency control method of a variable-frequency condensing fan and a refrigerating unit adopting the method.
Background
In the refrigerating unit, the variable-frequency condensing fan is adopted, and the frequency of the condensing fan is adjusted by a controller of the refrigerating unit according to the change of condensing load, so that the rotating speed is adjusted, the energy-saving effect of the refrigerating unit is good, the noise is low, the condensing pressure fluctuation is small, and the reliability of the refrigerating unit is remarkably improved. However, at low ambient temperature, the suction pressure of the refrigerating unit may be rapidly reduced at the instant of speed regulation of the condensing fan, and the suction pressure exceeds the application range of the compressor, so that the refrigerating unit is in a fault shutdown state or runs in an over-range state for a long time, the reliability of the compressor is reduced, and the service life of the refrigerating unit is shortened.
In the prior art, the frequency of the condensing fan is controlled according to the exhaust pressure, and therefore, how to provide a method for controlling the condensing fan with higher reliability is an urgent technical problem to be solved in the industry.
Disclosure of Invention
The invention provides a control method of a condensing fan and a refrigerating unit, and aims to solve the technical problem that the reliability of the unit is reduced at the moment of speed regulation easily due to speed regulation control of the condensing fan in the prior art.
The invention provides a control method of a condensing fan, which comprises the following steps:
step 1, monitoring exhaust pressure and suction pressure;
and 2, controlling the frequency of the condensing fan according to the relation between the exhaust pressure and the exhaust pressure control range and by combining the relation between the suction pressure and the suction pressure control range.
Further, the step 2 specifically includes: and in the process of increasing the exhaust pressure, if the exhaust pressure is less than or equal to the maximum value of the exhaust pressure control range, judging whether the suction pressure is greater than or equal to a suction pressure control limit value, and if so, controlling the condensation fan to perform frequency-up operation.
Further, the step 2 specifically includes: and in the process of reducing the exhaust pressure, if the exhaust pressure is greater than or equal to an exhaust pressure control limit value, judging whether the suction pressure is greater than or equal to a suction pressure control limit value, and if so, controlling the condensation fan to perform frequency-up operation.
Further, the step 2 specifically includes: and in the process of reducing the exhaust pressure, if the exhaust pressure is smaller than an exhaust pressure control limit value and is larger than or equal to the minimum value of an exhaust pressure control range, judging whether the suction pressure is larger than or equal to a suction pressure control limit value, and if so, controlling the condensing fan to maintain the current frequency operation.
In the above steps, if the suction pressure is less than the suction pressure control limit and the suction pressure is greater than or equal to the minimum value of the suction pressure control range, the condensation fan is controlled to operate in a frequency reduction mode. And if the suction pressure is smaller than the suction pressure control limit value and the suction pressure is smaller than the minimum value of the suction pressure control range, controlling the unit where the condensing fan is located to stop.
Further, the step 2 specifically includes: and in the process of increasing the exhaust pressure, if the exhaust pressure is greater than the maximum value of the exhaust pressure control range, controlling the unit where the condensing fan is positioned to stop.
Further, the step 2 specifically includes: and in the process of reducing the exhaust pressure, if the exhaust pressure is smaller than the minimum value of the exhaust pressure control range, judging whether the suction pressure is larger than or equal to the minimum value of the suction pressure control range, if so, controlling the condensation fan to operate in a frequency reduction mode, otherwise, controlling the unit where the condensation fan is positioned to stop.
In the present embodiment, the exhaust pressure control range is a minimum value obtained by subtracting the exhaust pressure control accuracy from the exhaust pressure control limit, and a maximum value obtained by adding the exhaust pressure control accuracy to the exhaust pressure control limit. The control range of the air suction pressure takes the air suction pressure control limit minus the air suction pressure control precision as the minimum value and takes the air suction pressure control limit plus the air suction pressure control precision as the maximum value.
The refrigerating unit provided by the invention comprises the condensing fan and the controller, wherein the controller controls the condensing fan by adopting the control method of the condensing fan in the technical scheme.
The invention controls the rotating speed of the condensing fan according to the exhaust pressure and the suction pressure, ensures that the rotating speed of the condensing fan is matched with the condensing load, maintains the stable suction pressure, and avoids the fault protection shutdown or the reliability reduction of the refrigerating unit caused by the over-range operation of the compressor.
Drawings
The invention is described in detail below with reference to examples and figures, in which:
fig. 1 is a control flowchart of a condensing fan of the present invention based on a variation in discharge pressure.
Fig. 2 is a control flowchart of the condensing fan of the present invention based on a change in suction pressure.
Detailed Description
The principles and embodiments of the present invention are described in detail below with reference to the accompanying drawings.
The condensation fan is a fan of a condensation side heat exchanger of the unit, when the unit is a single refrigerating unit, the condensation fan is a fan of an outdoor unit, and when the unit is a heat pump unit, the condensation fan is a fan of an indoor unit when the heat pump unit heats. The control of the condensing fan is adjusted based on the conditions of the exhaust pressure and the suction pressure of the compressor, and particularly, the frequency of the condensing fan is controlled by monitoring the exhaust pressure and the suction pressure and combining the relationship between the suction pressure and the suction pressure control range according to the relationship between the exhaust pressure and the exhaust pressure control range, so that the condensing fan cannot influence the reliability of a unit at the moment of speed regulation.
In the present embodiment, the exhaust pressure control range is the exhaust pressure control limit value P1Exhaust pressure subtraction control accuracy Δ P1At a minimum value, the limit value P is controlled by the exhaust pressure1Plus exhaust pressure control accuracy Δ P1Is at the maximum value, i.e. the exhaust pressure control range is [ P ]1-△P1, P1 +△P1]. Suction pressure control range to suction pressure control limit P2Control accuracy Δ P by subtracting suction pressure2At a minimum value, the limit value P is controlled by the suction pressure2Plus the control precision delta P of the suction pressure2At the maximum value, i.e. the suction pressure control range is [ P ]2-△P2, P2+△P2]. The exhaust pressure control limit may be an exhaust pressure protection value of the compressor, and the suction pressure control limit may be a suction pressure protection value of the compressor.
The control process of this patent will be described in detail below based on fig. 1 and 2 and the exhaust pressure control range and the intake pressure control range.
In the process of monitoring the exhaust pressure increase of the compressor, if the exhaust pressure P is detectedHeight ofNot more than the maximum value of the exhaust pressure control range, i.e. PHeight of≤P1 +△P1And then, continuously judging the current suction pressure, wherein the current suction pressure mainly comprises the following three conditions:
(1) if suction pressure PIs low inStable, i.e. suction pressure greater than or equal to suction pressure control limit PIs low in≥P2And if the suction pressure is stable, controlling the ascending frequency operation of the condensing fan to avoid overhigh exhaust pressure.
(2) If suction pressure PIs low inUnstable and suction pressure PIs low inIs not less than the minimum value of the suction pressure control range, i.e. P2-△P2≤PIs low in＜P2And controlling the condensation fan to perform frequency reduction operation so as to avoid over-low suction pressure.
(3) If suction pressure PIs low inUnstable and suction pressure PIs low inYet less than the minimum value of the suction pressure control range, i.e. PIs low in＜P2-△P2And controlling the unit where the condensing fan is positioned to stop so as to avoid the operation of the unit within the use range of the ultra-low pressure of the suction pressure and reduce the reliability of the unit.
In the process of monitoring the exhaust pressure increase of the compressor, if the exhaust pressure P is detectedHeight ofGreater than the maximum value of the exhaust-pressure control range, i.e. PHeight of＞P1 +△P1And in the process, the unit where the condensing fan is positioned is controlled to stop, so that the operation of the unit in the exhaust pressure ultrahigh pressure application range is avoided.
In the process of monitoring the reduction of the exhaust pressure of the compressor, if the exhaust pressure is detected to be more than or equal to the exhaust pressure control limit value, namely PHeight of≥P1Then, the current suction pressure is continuously determined, which mainly includes the following three conditions:
(1) if suction pressure PIs low inStable, i.e. suction pressure greater than or equal to suction pressure control limit PIs low in≥P2And if the suction pressure is stable, controlling the ascending frequency operation of the condensing fan to avoid overhigh exhaust pressure.
(2) If suction pressure PIs low inUnstable and suction pressure PIs low inIs not less than the minimum value of the suction pressure control range, i.e. P2-△P2≤PIs low in＜P2And controlling the condensation fan to perform frequency reduction operation so as to avoid over-low suction pressure.
(3) If suction pressure PIs low inUnstable and suction pressure PIs low inYet less than the minimum value of the suction pressure control range, i.e. PIs low in＜P2-△P2And controlling the unit where the condensing fan is positioned to stop so as to avoid the operation of the unit within the use range of the ultra-low pressure of the suction pressure and reduce the reliability of the unit.
In the process of monitoring the reduction of the exhaust pressure of the compressor, if the detected exhaust pressure is smaller than the exhaust pressure control limit value and is larger than or equal to the minimum value of the exhaust pressure control range, namely P1-△P1≤PHeight of＜P1Then, the current suction pressure is continuously determined, which mainly includes the following three conditions:
(1) if suction pressure PIs low inStable, i.e. suction pressure greater than or equal to suction pressure control limit PIs low in≥P2And if the suction pressure is stable, controlling the condensing fan to maintain the current frequency operation so as to avoid overhigh exhaust pressure.
(2) If suction pressure PIs low inUnstable and suction pressure PIs low inIs not less than the minimum value of the suction pressure control range, i.e. P2-△P2≤PIs low in＜P2And controlling the condensation fan to perform frequency reduction operation so as to avoid over-low suction pressure.
(3) If suction pressure PIs low inUnstable and suction pressure PIs low inYet less than the minimum value of the suction pressure control range, i.e. PIs low in＜P2-△P2And controlling the unit where the condensing fan is positioned to stop so as to avoid the operation of the unit within the use range of the ultra-low pressure of the suction pressure and reduce the reliability of the unit.
In the process of monitoring the reduction of the exhaust pressure of the compressor, if the exhaust pressure is detected to be smaller than the minimum value of the exhaust pressure control range, P is the minimum valueHeight of＜P1-△P1Then, the current suction pressure is continuously judged, which mainly includes the following two cases:
(1) if the suction pressure is greater than or equal to the minimum value of the suction pressure control range, namely PIs low in≥P2-△P2And the condensation fan is controlled to operate in a frequency reduction mode, so that the over-low suction pressure of the unit is avoided.
(2) If the suction pressure is less than the minimum value of the suction pressure control range, i.e. PIs low in＜P2-△P2And controlling the unit where the condensing fan is positioned to stop so as to avoid the operation of the unit within the use range of the ultra-low pressure of the suction pressure and reduce the reliability of the unit.
According to the invention, the exhaust pressure and the suction pressure are monitored simultaneously, and the frequency of the condensing fan is controlled according to the relation between the exhaust pressure and the suction pressure and the corresponding pressure control range, so that the exhaust pressure or the suction pressure cannot be caused to exceed the corresponding pressure control range at the moment of the change of the rotating speed of the condensing fan, and the reliability of the unit is ensured.
The invention also protects the refrigerating unit adopting the control method, and the controller of the refrigerating unit adopts the control method of the condensing fan to control the condensing fan.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A control method of a condensing fan is characterized by comprising the following steps:
step 1, monitoring exhaust pressure and suction pressure;
and 2, controlling the frequency of the condensing fan according to the relation between the exhaust pressure and the exhaust pressure control range and by combining the relation between the suction pressure and the suction pressure control range, wherein the control method comprises the following steps:
and in the process of increasing the exhaust pressure, if the exhaust pressure is less than or equal to the maximum value of the exhaust pressure control range, judging whether the suction pressure is greater than or equal to a suction pressure control limit value, and if so, controlling the condensation fan to perform frequency-up operation.
2. The method for controlling the condensing fan according to claim 1, wherein the step 2 specifically comprises:
and in the process of reducing the exhaust pressure, if the exhaust pressure is greater than or equal to an exhaust pressure control limit value, judging whether the suction pressure is greater than or equal to a suction pressure control limit value, and if so, controlling the condensation fan to perform frequency-up operation.
3. The method for controlling the condensing fan according to claim 1, wherein the step 2 specifically comprises: and in the process of reducing the exhaust pressure, if the exhaust pressure is smaller than an exhaust pressure control limit value and is larger than or equal to the minimum value of an exhaust pressure control range, judging whether the suction pressure is larger than or equal to a suction pressure control limit value, and if so, controlling the condensing fan to maintain the current frequency operation.
4. A method as claimed in any one of claims 1 to 3, wherein if the suction pressure is less than a suction pressure control limit and the suction pressure is greater than or equal to the minimum value of the suction pressure control range, the method controls the condensing fan to operate in a down-frequency mode.
5. A method as claimed in any one of claims 1 to 3, wherein if the suction pressure is less than a suction pressure control limit and the suction pressure is less than the minimum value of the suction pressure control range, the unit in which the condensing fan is located is controlled to stop.
6. The method for controlling the condensing fan according to claim 1, wherein the step 2 specifically comprises:
and in the process of increasing the exhaust pressure, if the exhaust pressure is greater than the maximum value of the exhaust pressure control range, controlling the unit where the condensing fan is positioned to stop.
7. The method for controlling the condensing fan according to claim 1, wherein the step 2 specifically comprises: and in the process of reducing the exhaust pressure, if the exhaust pressure is smaller than the minimum value of the exhaust pressure control range, judging whether the suction pressure is larger than or equal to the minimum value of the suction pressure control range, if so, controlling the condensation fan to operate in a frequency reduction mode, otherwise, controlling the unit where the condensation fan is positioned to stop.
8. The method of controlling a condensing fan according to claim 1, wherein the exhaust pressure control range is a minimum value of an exhaust pressure control limit minus an exhaust pressure control accuracy and a maximum value of an exhaust pressure control limit plus an exhaust pressure control accuracy.
9. The method of claim 1, wherein the suction pressure control range is a minimum value obtained by subtracting the suction pressure control accuracy from the suction pressure control limit, and a maximum value obtained by adding the suction pressure control accuracy to the suction pressure control limit.
10. A refrigeration unit comprising a condensing fan and a controller, wherein the controller controls the condensing fan by using the method of controlling the condensing fan according to any one of claims 1 to 9.
CN202010357462.4A 2020-04-29 2020-04-29 Control method of condensing fan and refrigerating unit Active CN111520895B (en)

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Publication number Priority date Publication date Assignee Title
CN113739462A (en) * 2021-08-18 2021-12-03 珠海格力电器股份有限公司 Defrosting mode switching method and related equipment thereof
CN115628530A (en) * 2022-10-26 2023-01-20 珠海格力电器股份有限公司 Fan control method, device and unit

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102679494A (en) * 2012-05-03 2012-09-19 宁波奥克斯电气有限公司 Control method of low temperature refrigeration of rooftop air conditioning unit
JP2014206304A (en) * 2013-04-11 2014-10-30 日立アプライアンス株式会社 Air conditioner
CN204026918U (en) * 2014-07-10 2014-12-17 深圳麦克维尔空调有限公司 A kind of air-conditioning system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102679494A (en) * 2012-05-03 2012-09-19 宁波奥克斯电气有限公司 Control method of low temperature refrigeration of rooftop air conditioning unit
JP2014206304A (en) * 2013-04-11 2014-10-30 日立アプライアンス株式会社 Air conditioner
CN204026918U (en) * 2014-07-10 2014-12-17 深圳麦克维尔空调有限公司 A kind of air-conditioning system

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