CN113154643B - Method for acquiring minimum running frequency of variable-frequency air cooling module - Google Patents

Method for acquiring minimum running frequency of variable-frequency air cooling module Download PDF

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CN113154643B
CN113154643B CN202110218383.XA CN202110218383A CN113154643B CN 113154643 B CN113154643 B CN 113154643B CN 202110218383 A CN202110218383 A CN 202110218383A CN 113154643 B CN113154643 B CN 113154643B
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CN113154643A (en
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邢震
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Weike Tianjin Co ltd
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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
    • F24F11/50—Control or safety arrangements characterised by user interfaces or communication
    • F24F11/54—Control or safety arrangements characterised by user interfaces or communication using one central controller connected to several sub-controllers
    • 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
    • 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
    • F24F11/65—Electronic processing for selecting an operating mode
    • F24F11/67—Switching between heating and cooling modes
    • 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
    • F24F11/72—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure
    • F24F11/74—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity
    • F24F11/77—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity by controlling the speed of ventilators
    • 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
    • F24F11/86—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling compressors within refrigeration or heat pump circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2110/00—Control inputs relating to air properties
    • F24F2110/10—Temperature
    • 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
    • F24F2140/20—Heat-exchange fluid temperature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

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  • Devices That Are Associated With Refrigeration Equipment (AREA)

Abstract

The invention provides a method for acquiring the lowest running frequency of a variable frequency air cooling module, which is characterized in that on the premise of the lowest rotating speed of an EC fan of the air cooling module, the running environment temperature and the effluent temperature of a unit under different working conditions are acquired to acquire the running lowest running frequency function of a variable frequency compressor, and then a controller sends an instruction to a variable frequency driver to adjust the allowable lowest running range of the variable frequency compressor. The method for acquiring the lowest operating frequency of the variable-frequency air-cooling module can accurately and effectively control the lowest operating frequency of the variable-frequency compressor through the ambient temperature and the water outlet temperature, and ensures the normal operation of the variable-frequency air-cooling module unit. Make inverter compressor all be in normal reasonable operation within range when different extreme condition moves, avoid appearing inverter compressor and surpassing the operation scope and lead to unable normal oil return of press, wearing and tearing aggravation, and then influence the phenomenon in unit life-span.

Description

Method for acquiring minimum running frequency of variable-frequency air cooling module
Technical Field
The invention belongs to the field of variable-frequency air-cooling module units, and particularly relates to a method for acquiring the lowest operating frequency of a variable-frequency air-cooling module.
Background
The direct-current variable-frequency air-cooling module unit has the advantages of wide operation range, high control precision, high cooling/heating IPLV and the like, can be suitable for various application occasions, and is more and more commonly used at home and abroad. However, when the direct-current variable-frequency air-cooling module unit operates in some extreme working conditions such as low-temperature refrigeration and high-temperature heating places, the following problems easily occur:
under the working conditions, when the variable-frequency air cooling module runs at a low running frequency, the lowest running pressure ratio cannot be reached, and the running range of the variable-frequency compressor is easily exceeded. In severe cases, the variable frequency compressor cannot return oil normally, and the abrasion is aggravated, so that the service life of the whole machine is influenced. Therefore, it is necessary to control the lowest operating frequency of the variable frequency air cooling module.
The lowest operating frequency of the inverter compressor is generally controlled by controlling the ambient temperature of the system or the suction/discharge pressure of the inverter compressor. However, the allowable suction pressure and discharge pressure of the inverter compressor are greatly different at different operating frequencies, so that the lowest allowable operating frequency of the inverter unit is determined simply according to one parameter of the ambient temperature or the suction/discharge pressure of the air cooling unit, which is not comprehensive and accurate enough, and deviation is easy to occur.
For the variable frequency compressor, parameters capable of directly reflecting the running state of the compressor are suction pressure and discharge pressure; however, due to the high cost of the pressure sensor, the pressure sensor needs to be directly installed in a system pipeline, and measurement is inconvenient. Moreover, for an air-cooled cold water (heat pump) unit adopting a variable-frequency compressor, the air suction pressure and the air discharge pressure are directly related to the operating environment temperature and the water outlet temperature of the module unit, and the air suction pressure and the air discharge pressure are acquired by using a temperature sensor, so that the measurement is convenient, and the cost price is low.
In addition, for the variable frequency air cooling module unit, under the extreme working conditions of low-temperature refrigeration and high-temperature heating, the minimum running rotating speed which can be reached by the fan is also one of the key factors influencing the lowest allowable running frequency of the unit, and the minimum running rotating speed must be acquired and used as a judgment condition. The normal design is that the rotating speed of the EC fan of the frequency conversion module unit is not allowed to be reduced to 0rpm, firstly, the running fluctuation of the unit is large due to the fact that the EC fan is frequently started and stopped, and secondly, the service life of the fan is influenced due to the fact that the EC fan is frequently started and stopped.
Disclosure of Invention
In view of this, the present invention aims to provide a method for obtaining a lowest operating frequency of a variable frequency air cooling module, which obtains a function of the lowest operating frequency of a variable frequency compressor by collecting operating environment temperatures and effluent temperatures of a unit under different working conditions on the premise of a lowest rotating speed of an EC fan of the air cooling module, and then sends an instruction to a variable frequency driver through a controller to adjust an allowable lowest operating range of the variable frequency compressor.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a method for obtaining the lowest running frequency of a variable-frequency air cooling module comprises the following steps:
s1: detecting the operation mode of the air cooling module unit, and judging whether the operation mode is a cooling mode or a heating mode;
s2: detecting whether the running speed of an EC fan of the air cooling module unit is the lowest running speed or not;
s3: collecting the operating environment temperature and the water outlet temperature of the air cooling module unit;
s4: calculating the allowable lowest operating frequency of the variable frequency compressor at the lowest EC fan operating speed according to the acquired operating environment temperature and the acquired outlet water temperature of the module unit, and dividing the allowable lowest operating frequency into the lowest operating frequency of a refrigeration mode and the lowest operating frequency of a heating mode;
s5: and the controller sends the calculated lowest operation frequency instruction to a driver of the variable frequency compressor, and when the air conditioning system needs to unload and reduce the frequency, the compressor is ensured not to operate below the lowest operation frequency, so that the safe and stable operation of the compressor is protected.
Furthermore, the minimum running speed of the EC fan is a system set value and is given by different fan manufacturers according to the fan characteristics.
Further, the step S4 is carried out at different ambient temperaturesTa. Different water outlet temperaturesTAnd w, the calculation formula of the lowest operation frequency of the refrigeration mode of the variable frequency compressor is as follows:
Figure DEST_PATH_IMAGE002
under the condition of ensuring the lowest running rotating speed of the EC fan, the lowest water outlet temperature isT cmin The temperature of the effluent is
Figure DEST_PATH_IMAGE004
The deviation value of the water temperature is delta t, and the ambient temperature isT 1 Deviation value of ambient temperature of Δ t 1 The ratio is K 1 ；
Under the condition of ensuring the minimum running rotating speed of the EC fan, the lowest running frequency of the compressor meeting the condition of the running range of the compressor isf 1 Minimum operating frequency f of compressor under different working conditions min 。
Further, the ratio value K of the refrigeration mode 1 The acquisition step comprises:
s401: set the lowest cooling water of the air-cooled modular unitAt a temperature ofTcmin, experimental acquisitionT1 at the ring temperature, the outlet water temperature isTcmin, under the condition of ensuring the lowest running speed of the EC fan, the lowest compressor running frequency meeting the condition of the compressor running range is f1, the running frequency f1 is the set minimum running frequency of the compressor under any working condition, and the relation between the running frequency f1 and the lowest running frequency fmin of the compressor under different working conditions is that fmin is not less than f1, thus a point (f) is determined in the X-Y coordinate axisT1,f1)；
S402: extending a single point to a single line: when the ring temperature is reduced to the lowest allowable operation ring temperature T3 of the frequency conversion module, the lowest allowable operation frequency of the compressor is increased tof3, according to the measured data and theoretical calculation, at the same water temperature, the decrease of the ring temperature and the increase of the lowest frequency of the compressor are in inverse proportion relation, and are connected in an X-Y coordinate axis (T1,f1)、(T3,f3) The following piecewise function is obtained as shown by the straight line segment of (a):
Figure DEST_PATH_IMAGE006
s403: expanding the straight line segment to a straight line segment beam to deduce the lowest operation frequency allowed by the compressor at different ring temperatures under a certain other specific water outlet temperature; based on the measured data and the simulation inference, the environment temperature can be setT1. As a starting point, any delta t1 ring temperature unit is increased/decreased, and under the condition of the lowest rotating speed of the EC fan, the allowable unit refrigeration effluent temperature corresponding to the reasonable operation range of the compressor can be increased/decreased by any delta t2 water temperature unit, so that the piecewise function correlation can be rewritten into the following form:
Figure DEST_PATH_IMAGE008
initial ambient temperature ofT1, the initial ambient temperature is delta t1,
the correlation being indicative of a particular water outlet temperature
Figure 296749DEST_PATH_IMAGE004
Under the condition, the lowest running frequency of the compressor allowed by the air-cooled modular unit at different ring temperatures is determined;
the correlation expression is only the lowest operation frequency of the variable frequency compressor allowed under different specific water temperatures and different ring temperatures;
s405: expanding the linear segment beam to an area plane: namely deducing the temperature at different ring temperaturesTaAnd different water temperaturesTwThe lowest running frequency of the time-varying frequency compressor;
setting the water outlet temperature and the water temperature
Figure 479469DEST_PATH_IMAGE004
The deviation value is delta t water temperature unit, and the environment temperature is setT1 is a starting point, any delta t1 environmental temperature unit is increased/decreased, and any delta t2 water temperature unit is increased/decreased in the allowable unit refrigeration water outlet temperature corresponding to the reasonable operation range of the compressor under the condition of the lowest rotation speed of the EC fan;
after the water temperature changes by delta t, the change of the ambient temperature is delta t 1 /Δt 2 Therefore, the translation value of the straight-line segment along the Y-axis direction can be known according to the slope of the straight-line segment as follows:
Figure DEST_PATH_IMAGE010
order ratio value
Figure DEST_PATH_IMAGE012
，
Wherein the lowest environment temperature allowed by the frequency converter to operate isT 3 Correspond toT 3 The lowest operating frequency at ambient temperature isf 3 。
Further, the step S4 is carried out at different ambient temperaturesTa. Different water outlet temperaturesTAnd w, the calculation formula of the lowest operation frequency of the heating mode of the variable frequency compressor is as follows:
Figure DEST_PATH_IMAGE014
under the condition of ensuring the lowest running rotating speed of the EC fan, the lowest water outlet temperature isT hmin The temperature of the effluent is
Figure DEST_PATH_IMAGE016
The deviation value of the water temperature is delta t, and the ambient temperature isT 1 Deviation value of ambient temperature of Δ t 1 The ratio value is K 2 ；
Under the condition of ensuring the minimum running rotating speed of the EC fan, the lowest running frequency of the compressor meeting the condition of the running range of the compressor isf 1 Minimum operating frequency f of compressor under different working conditions min 。
Further, the proportional value K of the heating mode 2 The acquisition step also adopts a point-line-plane expansion form, and the lowest heating outlet water temperature of the air cooling module unit is set asThmin, measuring the ambient temperatureTUnder the condition of 2-ring temperature and under the condition of ensuring the lowest running rotating speed of the EC fan, the lowest compressor running frequency meeting the condition of the running range of the compressor isf1; keeping the temperature of the discharged water unchanged and increasing the ring temperatureT2, under the condition of maintaining the lowest running speed of the EC fan, the evaporation pressure is continuously increased, and the condensation pressure is unchanged, so the frequency-increasing control needs to be carried out on the variable-frequency compressor until the ring temperature is increased to the maximum allowable ring temperature of the unitT4, the corresponding compressor frequency should be increasedf4, the variable frequency compressor can be ensured to be in a reasonable operation range;
different from the refrigeration mode, under the same water temperature, the rising of the environmental temperature is in direct proportion to the rising of the lowest frequency of the compressor,
Figure DEST_PATH_IMAGE018
，
wherein the maximum environment temperature allowed by the frequency converter isT 4 Correspond toT 4 The lowest operating frequency at ambient temperature isf 4 。
Compared with the prior art, the method for acquiring the lowest operating frequency of the variable-frequency air-cooling module has the following beneficial effects:
on the premise of confirming the operation mode of the variable-frequency air-cooling module unit and the running rotating speed of the fan, the lowest running frequency of the variable-frequency compressor of the air-cooling module is controlled by acquiring the running ambient temperature of the unit and the water outlet temperature of the module. Firstly, the environmental temperature and the effluent temperature are convenient to measure; and for the air cooling module unit, the ambient temperature and the outlet water temperature are working condition parameters which directly influence the low-pressure evaporation side or the high-pressure condensation side of the unit and are directly related to the suction and exhaust parameters of the variable frequency compressor. Therefore, the lowest running frequency of the variable-frequency compressor can be accurately and effectively controlled through the ambient temperature and the water outlet temperature, and the normal running of the variable-frequency air-cooled module unit is ensured. Make inverter compressor all be in normal reasonable operation within range when different extreme condition moves, avoid appearing inverter compressor and surpassing the operation scope and lead to unable normal oil return of compressor, wearing and tearing aggravation, and then influence the phenomenon in unit life-span.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic flow chart of a method for acquiring the lowest operating frequency of a variable frequency air cooling module according to an embodiment of the present invention;
fig. 2 is a graph showing a function curve between the lowest operating frequency of the compressor, the operating environment temperature of the module, and the outlet water temperature during the cooling operation according to the method for obtaining the lowest operating frequency of the variable frequency air-cooling module in the embodiment of the present invention;
fig. 3 is a graph illustrating a function between the lowest operating frequency of the compressor, the operating environment temperature of the module, and the outlet water temperature during heating operation according to the method for acquiring the lowest operating frequency of the variable frequency air-cooling module in the embodiment of the present invention;
description of reference numerals:
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.
The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
As shown in fig. 1, a method for obtaining the lowest operating frequency of a variable frequency air cooling module is characterized in that: the method comprises the following steps:
s1, firstly, detecting an operation mode, a refrigeration mode or a heating mode of an air-cooling module unit;
and S2, secondly, detecting whether the running rotating speed of the EC fan of the variable-frequency air-cooled modular unit is the lowest rotating speed. The step aims to solve the problems that generally, under a specific working condition, the higher the rotating speed of the variable frequency compressor is, the higher the exhaust pressure is, the lower the suction pressure is, and the larger the suction-exhaust pressure difference is; the lower the rotating speed of the variable frequency compressor is, the lower the exhaust pressure is, the higher the suction pressure is, and the smaller the suction-exhaust pressure difference is. Therefore, under the working condition that specific low-temperature refrigeration is carried out at a high water outlet temperature, the minimum running wind speed of the EC fan is given, and the premise that the maximum high-pressure of the condensation side under the working condition is ensured, and the corresponding rotating speed of the variable-frequency compressor is the lowest allowable running rotating speed; similarly, under the conditions of high-temperature heating and low water outlet temperature, the given minimum running wind speed of the EC fan is the premise of ensuring the minimum low-pressure of the evaporation side under the working condition, and the corresponding rotating speed of the variable frequency compressor is the lowest allowable running rotating speed; therefore, the minimum operation rotating speed of the EC fan is the premise basis for calculating the minimum operation frequency of the variable-frequency air-cooling module unit and needs to be judged.
S3, collecting the operating environment temperature of the air-cooled module unit and the module water outlet temperature in real time;
s4, respectively calculating the allowable lowest running frequency of the variable frequency compressor at the lowest EC fan running speed according to the collected running environment temperature and the collected water outlet temperature of the module unit;
and S5, the controller sends the calculated lowest operation frequency instruction to a variable frequency compressor driver, and when the air conditioning system needs to unload and reduce the frequency, the compressor is ensured not to operate below the lowest operation frequency, so that the safe and stable operation of the compressor is protected.
As shown in fig. 2, a function curve graph between the lowest operating frequency of the compressor and the operating environment temperature and the outlet water temperature of the module during the cooling operation is provided, and the fitting of the function curve graph is described in detail below:
firstly, the lowest refrigeration outlet water temperature of the air cooling module unit is set to beTcmin. Measured by experiment atT1 at the ring temperature, the outlet water temperature isTcmin, under the condition of ensuring the lowest running speed of the EC fan, the lowest compressor running frequency meeting the condition of the compressor running range is f1, the running frequency f1 is the relation between the set minimum running frequency of the compressor under any working condition and the lowest running frequency fmin of the compressor under different working conditionsFmin is not less than f 1; thus, in the X-Y coordinate axis in determining a point (T1,f1)；
Further, a single point extends to a single line: keeping the lowest outlet water temperature of the air cooling moduleTcmin is unchanged, and the ring temperature is continuously raisedT1, under the same lowest wind speed, the higher the ring temperature is, the higher the high pressure of the condensation side is, and the temperature of the water outlet of the evaporation side is kept unchanged, so that the frequency reduction treatment of the variable frequency compressor is required to ensure the operation range of the compressor. However, the system sets the minimum compressor speed tof1 cannot be changed, therefore, the temperature is higher than the temperature of the ringTAt 1, the lowest allowable compressor operating frequency is stillf1. On the contrary, the ring temperature is continuously loweredT1, under the same lowest wind speed, the lower the ring temperature, the lower the high pressure on the condensation side, and the constant temperature on the evaporation side, and the frequency raising treatment of the frequency conversion compressor is needed to ensure the operation range of the compressor. When the ring temperature is reduced to the lowest allowable operating ring temperature T3 of the frequency conversion module, the lowest allowable operating frequency of the compressor is increased tof3. According to the measured data and theoretical calculation, at the same water temperature, the decrease of the ambient temperature and the increase of the lowest frequency of the compressor are in inverse proportion, as shown in figure 2 connection: (T1,f1)、(T3,f3) The following piecewise function is obtained as shown by the straight line segment of (a):
Figure DEST_PATH_IMAGE006A
further, as can be seen from the above, the compressor allows the lowest operating frequency to be lowered as the ring temperature increases at the same water temperature; therefore, the straight line segment is expanded to a straight line segment beam to deduce the lowest operation frequency allowed by the compressor under a certain other specific water outlet temperature and different ring temperatures; based on the measured data and the simulation inference, the environment temperature can be setT1. Increasing/decreasing any delta t1 ring temperature unit as a starting point, ensuring that the refrigerating outlet water temperature of the unit allowed corresponding to the reasonable operation range of the compressor can be increased/decreased by any delta t2 water temperature unit under the condition of the lowest rotating speed of the EC fan, and then changing the piecewise function correlation formulaWritten as follows:
Figure DEST_PATH_IMAGE008A
T1 is the initial ambient temperature, Δ t1 is the initial ambient temperature
The correlation being indicative of a particular water outlet temperature
Figure 757741DEST_PATH_IMAGE004
Under the condition, the lowest running frequency of the compressor allowed by the air cooling module unit at different ring temperatures is determined;
the correlation expression only indicates the lowest operation frequency of the inverter compressor, which is allowed under different specific water temperatures and different environment temperatures.
Now, the above-mentioned linear segment beam is expanded to the area surface: namely deducing the temperature at different ring temperaturesTaAnd different water temperaturesTwThe lowest operating frequency at which the time-varying compressor operates. Similarly, the set water temperature and the water temperature
Figure 559475DEST_PATH_IMAGE004
The deviation value is a delta t water temperature unit, and according to the set conditions: set to the ring temperatureT1 is a starting point, any delta t1 environmental temperature unit is increased/decreased, and any delta t2 water temperature unit is allowed to be increased/decreased by the refrigerating water temperature allowed by the unit corresponding to the reasonable operation range of the compressor under the condition of the lowest rotating speed of the EC fan.
After the water temperature changes by delta t, the change of the ambient temperature is delta t 1 /Δt 2 Therefore, the translation value of the straight-line segment along the Y-axis direction can be known according to the slope of the straight-line segment as follows:
Figure DEST_PATH_IMAGE010A
order to
Figure 262596DEST_PATH_IMAGE012
，
Therefore, the lowest operating frequency of the variable frequency compressor under different ring temperatures and different water outlet temperatures can be obtained:
Figure DEST_PATH_IMAGE020
the meaning of the plus or minus sign in the expression is as follows: "+" indicates that the outlet water temperature is higher than the current water temperature; "-" indicates that the outlet water temperature is lower than the current water temperature;
in the above expression except
Figure DEST_PATH_IMAGE022
And
Figure DEST_PATH_IMAGE024
other parameters are known set parameters and can be given according to actual operation parameters of the frequency conversion module unit;
in addition, as can be seen from the correlation, when the outlet water temperature is lower than the current water temperature, the result fmin <f1, which exceeds the minimum operating frequency of the compressor allowed by the system settings, must be defined, as follows:
Figure DEST_PATH_IMAGE002A
fig. 3 shows a function curve diagram of the lowest operating frequency of the compressor, the operating environment temperature of the module, and the outlet water temperature during heating operation according to the method for obtaining the lowest operating frequency of the variable frequency air cooling module provided by the present invention; the heating operation limit condition is generally the condition of high ambient temperature and low water outlet temperature, at this time, the water outlet temperature is low, the condensing pressure is low, but the ambient temperature evaporating side temperature is higher, resulting in higher evaporating side pressure, which may cause the high-low pressure difference of the compressor not to meet the design requirement. The rotating speed range of the EC fan directly influences the low pressure of the evaporation side, the rotating speed of the EC fan is high, the heat absorption of the evaporation side is high, and the evaporation pressure is high; and if the rotating speed of the EC fan is low, the heat absorption of the refrigerant at the evaporation side is less, and the evaporation pressure is low. Therefore, under the derivation heating mode, when the lowest operation frequency of the variable frequency compressor is allowed, the lowest operation speed of the EC fan is also used as a precondition;
similarly, aiming at the heating mode, an expansion form of point-line-surface is also adopted; the lowest heating water outlet temperature of the air cooling module unit is set to beThmin, measured experimentally atTAt the ring temperature, the outlet water temperature isThmin, the lowest compressor running frequency meeting the condition of the compressor running range under the condition of ensuring the lowest running rotating speed of the EC fan isf1; keeping the temperature of the discharged water unchanged and increasing the ring temperatureT2, under the condition of maintaining the lowest running speed of the EC fan, the evaporation pressure is continuously increased, and the condensation pressure is unchanged, so the frequency-increasing control needs to be carried out on the variable-frequency compressor until the ring temperature is increased to the maximum allowable ring temperature of the unitT4, the corresponding compressor frequency should be increasedf4, the inverter compressor can be ensured to be in a reasonable operation range. Unlike the refrigeration mode, at the same water temperature, the increase of the ambient temperature is in direct proportion to the increase of the lowest frequency of the compressor, namely the following correlation:
Figure DEST_PATH_IMAGE026
similarly, set to the ring temperatureT2. As a starting point, any delta t1 ring temperature unit is increased/decreased, under the condition of the lowest rotating speed of the EC fan, the refrigeration outlet water temperature of the unit is allowed to be increased/decreased by any delta t2 water temperature unit corresponding to the reasonable operating range of the compressor, and then the outlet water temperature can be calculated
Figure 553900DEST_PATH_IMAGE016
Under the condition, the lowest operation frequency of the compressor allowed by the air cooling module unit at different ring temperatures is as follows:
order to
Figure 227458DEST_PATH_IMAGE018
，
Figure DEST_PATH_IMAGE028
Therefore, the lowest allowable operating frequency of the variable frequency compressor under different ring temperatures and different water outlet temperatures in the heating mode can be obtained:
Figure DEST_PATH_IMAGE014A
the above is a detailed description of the method for controlling the lowest operating frequency of the variable frequency air-cooled modular unit. According to the invention, on the premise of the lowest rotating speed of the EC fan of the air cooling module, the curve of the lowest operating frequency of the variable frequency compressor is fitted by collecting the operating environment temperature and the water outlet temperature of the unit under different working conditions, and then the controller sends an instruction to the variable frequency driver to adjust the lowest allowable operating range of the variable frequency compressor.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the present invention, which is intended to cover any modifications, equivalents, improvements, etc. within the spirit and scope of the present invention.

Claims (4)

1. A method for obtaining the lowest running frequency of a variable-frequency air cooling module is characterized by comprising the following steps: the method comprises the following steps:
s1: detecting the operation mode of the air cooling module unit, and judging whether the operation mode is a cooling mode or a heating mode;
s2: detecting whether the running speed of an EC fan of the air cooling module unit is the lowest running speed or not;
s3: collecting the operating environment temperature and the water outlet temperature of the air cooling module unit;
s4: calculating the allowable lowest operating frequency of the variable frequency compressor at the lowest EC fan operating speed according to the acquired operating environment temperature and the acquired outlet water temperature of the module unit, and dividing the allowable lowest operating frequency into the lowest operating frequency of a refrigeration mode and the lowest operating frequency of a heating mode;
s5: the controller sends the calculated lowest operation frequency instruction to a variable frequency compressor driver, and when the air conditioning system needs to unload and reduce the frequency, the compressor is ensured not to operate below the lowest operation frequency, so that the safe and stable operation of the compressor is protected;
the step S4 is carried out at different environmental temperaturesTa. Different water outlet temperaturesTAnd w, the calculation formula of the lowest operation frequency of the refrigeration mode of the variable frequency compressor is as follows:
Figure DEST_PATH_IMAGE001
under the condition of ensuring the lowest running rotating speed of the EC fan, the lowest water outlet temperature isT cmin The temperature of the effluent is
Figure 297535DEST_PATH_IMAGE002
The deviation value of the water temperature is delta t, and the ambient temperature isT 1 Deviation value of ambient temperature of Δ t 1 The ratio is K 1 ；
The lowest compressor running frequency meeting the condition of the running range of the compressor under the condition of ensuring the lowest running rotating speed of the EC fan isf 1 Minimum operating frequency f of compressor under different working conditions min ；
The step S4 is carried out at different environmental temperaturesTa. Different water outlet temperaturesTAnd w, the calculation formula of the lowest operation frequency of the heating mode of the variable frequency compressor is as follows:
Figure 706650DEST_PATH_IMAGE003
under the condition of ensuring the lowest running rotating speed of the EC fan, the lowest water outlet temperature isT hmin The temperature of the effluent is
Figure 761194DEST_PATH_IMAGE004
The deviation value of the water temperature is delta t, and the ambient temperature isT 1 Deviation value of ambient temperature of Δ t 1 The ratio is K 2 ；
Meeting the condition of compressor operation range under the condition of ensuring the lowest running speed of the EC fanThe lowest press operating frequency isf 1 Minimum operating frequency f of compressor under different working conditions min 。
2. The method for acquiring the lowest operating frequency of the variable-frequency air-cooling module according to claim 1, wherein the method comprises the following steps: the minimum running speed of the EC fan is a set value of the system and is given by different fan manufacturers according to the characteristics of the fan.
3. The method for acquiring the lowest operating frequency of the variable-frequency air cooling module according to claim 1, wherein the method comprises the following steps: ratio value K of refrigeration mode 1 The obtaining step comprises:
s401: the lowest refrigerating outlet water temperature of the air cooling module unit is set toTcmin, experimental acquisitionT1 at the ring temperature, the outlet water temperature isTcmin, under the condition of ensuring the lowest running speed of the EC fan, the lowest press running frequency meeting the condition of the running range of the compressor is f1, the running frequency f1 is the set minimum running frequency of the compressor under any working condition, and the relation between the running frequency f and the lowest running frequency fmin of the compressor under different working conditions is that fmin is more than or equal to f1, so that a point (a point is determined in an X-Y coordinate axis)T1,f1)；
S402: extending a single point to a single line: when the ring temperature is reduced to the lowest allowable operation ring temperature T3 of the frequency conversion module, the lowest allowable operation frequency of the press is increased tof3, according to the measured data and theoretical calculation, at the same water temperature, the decrease of the ring temperature and the increase of the lowest frequency of the press are in inverse proportion relation, and are connected in an X-Y coordinate axis (T1,f1)、(T3,f3) The following piecewise function is obtained as shown by the straight line segment of (a):
Figure 348296DEST_PATH_IMAGE005
s403: expanding the straight line segment to a straight line segment bundle to deduce the lowest operation frequency allowed by the compressor at different ring temperatures under a certain other specific water outlet temperature; based on the measured data and simulation inference, the environmental temperature can be setT1. Is composed ofAt the starting point, any delta t1 environmental temperature unit is increased/decreased, and under the condition of the lowest rotating speed of the EC fan, the refrigeration outlet water temperature of the unit allowed corresponding to the reasonable operating range of the press is ensured to be increased/decreased by any delta t2 water temperature unit, so that the piecewise function correlation formula can be rewritten into the following form:
Figure 121080DEST_PATH_IMAGE006
initial ambient temperature ofT1, the initial ambient temperature is Δ t1,
the correlation being indicative of a particular water outlet temperature
Figure 802728DEST_PATH_IMAGE002
Under the condition, the lowest operation frequency of the press allowed by the air cooling module unit at different ring temperatures;
the correlation expression only indicates the lowest operation frequency of the variable frequency compressor which is allowed under different specific water temperatures and different environment temperatures;
s405: expanding the linear segment beam to an area surface: namely deducing the temperature at different ring temperaturesTaAnd different water temperaturesTwThe lowest running frequency of the time-varying frequency compressor;
setting the water outlet temperature and the water temperature
Figure 977357DEST_PATH_IMAGE002
The deviation value is delta t water temperature unit, and the environmental temperature is setT1 is taken as a starting point, any delta t1 environment temperature unit is increased/decreased, and under the condition of the lowest rotating speed of an EC fan, the refrigerating water outlet temperature of a unit which is allowed to be correspondingly within the reasonable operating range of a press is allowed to be increased/decreased by any delta t2 water temperature unit;
after the water temperature changes by delta t, the ring temperature changes by delta t 1 /Δt 2 Therefore, the translation value of the straight-line segment along the Y-axis direction can be known according to the slope of the straight-line segment as follows:
Figure DEST_PATH_IMAGE007
order ratio value
Figure 640420DEST_PATH_IMAGE008
，
Wherein the lowest environment temperature allowed by the frequency converter to operate isT 3 Correspond toT 3 The lowest operating frequency at ambient temperature isf 3 。
4. The method for acquiring the lowest operating frequency of the variable-frequency air-cooling module according to claim 1, wherein the method comprises the following steps: proportional value K of heating mode 2 The acquisition step also adopts a point-line-plane expansion form, and the lowest heating outlet water temperature of the air cooling module unit is set to beThmin, measuring the ambient temperatureTUnder the condition of 2-ring temperature and under the condition of ensuring the lowest running rotating speed of the EC fan, the lowest compressor running frequency meeting the condition of the running range of the compressor isf1; keeping the temperature of the discharged water unchanged and raising the temperature of the ringT2, under the condition of maintaining the lowest running speed of the EC fan, the evaporation pressure is continuously increased, and the condensation pressure is unchanged, so the frequency-increasing control needs to be carried out on the variable-frequency compressor until the ring temperature is increased to the maximum allowable ring temperature of the unitT4, the corresponding compressor frequency should be increasedf4, the variable frequency compressor can be ensured to be in a reasonable operation range;
different from the refrigeration mode, under the same water temperature, the rising of the ring temperature is in direct proportion to the rising of the lowest frequency of the compressor,
Figure DEST_PATH_IMAGE009
，
wherein the maximum environment temperature allowed by the frequency converter isT 4 Correspond toT 4 The lowest operating frequency at ambient temperature isf 4 。
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CN114087733B (en) * 2021-11-17 2022-12-13 珠海格力电器股份有限公司 Control method of air conditioner and air conditioner
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010196975A (en) * 2009-02-25 2010-09-09 Denso Corp Refrigerating cycle apparatus
CN103836762A (en) * 2012-11-22 2014-06-04 广东美的制冷设备有限公司 Variable frequency air conditioner and method and device for controlling variable frequency air conditioning system
CN108397853A (en) * 2018-02-11 2018-08-14 珠海格力电器股份有限公司 Air-conditioner set control method and device

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005147540A (en) * 2003-11-17 2005-06-09 Matsushita Electric Ind Co Ltd Heat pump water heater
CN105716203B (en) * 2016-03-03 2018-10-19 海信（山东）空调有限公司 Convertible frequency air-conditioner minimum frequency control method
CN107270601B (en) * 2017-07-07 2020-06-16 青岛海尔空调电子有限公司 Control method of water chilling unit
CN108375175B (en) * 2018-02-08 2019-09-24 珠海格力电器股份有限公司 Air conditioner system control method and device
CN108800458B (en) * 2018-04-28 2020-07-07 四川虹美智能科技有限公司 Method and device for controlling frequency of compressor in air conditioner
CN109556331A (en) * 2018-12-12 2019-04-02 珠海格力电器股份有限公司 A kind of water chiller and its temperature control method of water
CN111023264A (en) * 2019-12-25 2020-04-17 宁波奥克斯电气股份有限公司 Air conditioner and control method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010196975A (en) * 2009-02-25 2010-09-09 Denso Corp Refrigerating cycle apparatus
CN103836762A (en) * 2012-11-22 2014-06-04 广东美的制冷设备有限公司 Variable frequency air conditioner and method and device for controlling variable frequency air conditioning system
CN108397853A (en) * 2018-02-11 2018-08-14 珠海格力电器股份有限公司 Air-conditioner set control method and device

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