阅读说明：本技术 冷凝风机的控制方法、制冷机组 (Control method of condensing fan and refrigerating unit ) 是由 杨虹 卫广穹 张正 于 2020-04-29 设计创作，主要内容包括：本发明公开了一种冷凝风机的控制方法、制冷机组。其中冷凝风机的控制方法,包括：监控排气压力和吸气压力；根据所述排气压力与排气压力控制范围的关系,结合所述吸气压力与吸气压力控制范围的关系,对所述冷凝风机的频率进行控制。本发明在对冷凝风机的频率进行控制时,同时参考压缩机的排气压力和吸气压力,确保冷凝风机的转速与冷凝负荷相匹配,同时维持低压压力稳定,确保机组的可靠性。(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.)

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.

2. 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 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.

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 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.

4. 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.

5. A method as claimed in any one of claims 2 to 4, 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.

6. A control method of a condensing fan according to any one of claims 2 to 4, characterized in that if the suction pressure is less than a suction pressure control limit value and the suction pressure is less than the minimum value of the suction pressure control range, the unit where the condensing fan is located is controlled 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 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.

8. 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.

9. 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.

10. 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.

11. 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 10.

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.

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 control accuracy subtracted △ P₁At a minimum value, the limit value P is controlled by the exhaust pressure₁Plus exhaust pressure control accuracy △ 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 P₂Subtracted suction pressure control accuracy △ P₂At a minimum value, the limit value P is controlled by the suction pressure₂Plus the control accuracy of the suction pressure △ P₂At 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 detected_{Height of}Not more than the maximum value of the exhaust pressure control range, i.e. P_{Height 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 P_{Is low in}Stable, i.e. suction pressure greater than or equal to suction pressure control limit P_{Is 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 P_{Is low in}Unstable and suction pressure P_{Is low in}Is not less than the minimum value of the suction pressure control range, i.e. P₂-△P₂≤P_{Is low in}＜P₂And controlling the condensation fan to perform frequency reduction operation so as to avoid over-low suction pressure.

(3) If suction pressure P_{Is low in}Unstable and suction pressure P_{Is low in}Yet less than the minimum value of the suction pressure control range, i.e. P_{Is 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 detected_{Height of}Greater than the maximum value of the exhaust-pressure control range, i.e. P_{Height 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 P_{Height of}≥P₁Then, the current suction pressure is continuously determined, which mainly includes the following three conditions:

(1) if suction pressure P_{Is low in}Stable, i.e. suction pressure greater than or equal to suction pressure control limit P_{Is low in}≥P₂If inhalingAnd if the pressure is stable, controlling the ascending frequency operation of the condensing fan to avoid overhigh exhaust pressure.

(2) If suction pressure P_{Is low in}Unstable and suction pressure P_{Is low in}Is not less than the minimum value of the suction pressure control range, i.e. P₂-△P₂≤P_{Is low in}＜P₂And controlling the condensation fan to perform frequency reduction operation so as to avoid over-low suction pressure.

(3) If suction pressure P_{Is low in}Unstable and suction pressure P_{Is low in}Yet less than the minimum value of the suction pressure control range, i.e. P_{Is 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≤P_{Height of}＜P₁Then, the current suction pressure is continuously determined, which mainly includes the following three conditions:

(1) if suction pressure P_{Is low in}Stable, i.e. suction pressure greater than or equal to suction pressure control limit P_{Is 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 P_{Is low in}Unstable and suction pressure P_{Is low in}Is not less than the minimum value of the suction pressure control range, i.e. P₂-△P₂≤P_{Is low in}＜P₂And controlling the condensation fan to perform frequency reduction operation so as to avoid over-low suction pressure.

(3) If suction pressure P_{Is low in}Unstable and suction pressure P_{Is low in}Yet less than the minimum value of the suction pressure control range, i.e. P_{Is 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 value_{Height 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 P_{Is 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. P_{Is 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.