CN115355640B - Method and device for controlling water chilling unit, water chilling unit and storage medium - Google Patents

Method and device for controlling water chilling unit, water chilling unit and storage medium Download PDF

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Publication number
CN115355640B
CN115355640B CN202211034760.5A CN202211034760A CN115355640B CN 115355640 B CN115355640 B CN 115355640B CN 202211034760 A CN202211034760 A CN 202211034760A CN 115355640 B CN115355640 B CN 115355640B
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Prior art keywords
compressor
rotating speed
load
water temperature
coefficient
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CN115355640A (en
Inventor
任文臣
张志平
张捷
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Qingdao Haier Central Air Conditioner Co Ltd
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Qingdao Haier Central Air Conditioner Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/40—Fluid line arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F25B49/022—Compressor control arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/021—Inverters therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/025—Compressor control by controlling speed
    • 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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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)

Abstract

The application relates to the technical field of refrigeration and discloses a method for controlling a water chilling unit, which comprises the following steps: obtaining the frequency of the rotating speed of the compressor and the load shedding control quantity; acquiring a differential pressure fluctuation control amount of the rotating speed of the compressor; and adjusting the rotating speed of the compressor according to the frequency loading and unloading control quantity and the pressure difference fluctuation control quantity. The frequency is controlled through the frequency converter, hysteresis existing in control is considered, and the subsequent adjustment process of the rotating speed of the motor of the compressor is optimized. Meanwhile, the influence of compressor frequency fluctuation on the oil return performance of the water chilling unit is considered, and the fluctuation condition of the pressure difference of the air suction and the air discharge of the compressor is monitored, so that the corresponding control quantity is introduced, the adjustment of the rotating speed of the compressor is more accurate, and the stable operation of the water chilling unit is facilitated. The application also discloses a device for controlling the water chilling unit, the water chilling unit and a storage medium.

Description

Method and device for controlling water chilling unit, water chilling unit and storage medium
Technical Field
The present disclosure relates to the field of refrigeration technologies, and for example, to a method and an apparatus for controlling a water chiller, and a storage medium.
Background
At present, a water chilling unit generally judges specific load conditions by calculating water temperature change, and controls a compressor by adopting a variable-frequency speed regulation method, so that continuous adjustment of cold energy is realized. And the prepared cold energy is transferred to the water body, so that the water temperature is always kept near the expected value.
In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art:
the related technology has higher control precision requirement on variable frequency speed regulation. If the adjustment of the rotation speed of the compressor is controlled by only a simple up-down operation, the water temperature may be excessively adjusted due to the hysteresis of the water temperature change. And then causes frequent ascending and descending frequency of the compressor, which is unfavorable for the stable operation of the water chilling unit. Meanwhile, the variable frequency control of the compressor also affects the oil return effect of the unit. The frequent frequency rising and falling phenomenon of the compressor can further cause the phenomenon of oil leakage of the compressor, and the running stability of the water chilling unit is seriously affected.
Disclosure of Invention
The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview, and is intended to neither identify key/critical elements nor delineate the scope of such embodiments, but is intended as a prelude to the more detailed description that follows.
The embodiment of the disclosure provides a method and a device for controlling a water chiller, the water chiller and a storage medium, which can enable the adjustment of the rotation speed of a compressor to be more accurate and are beneficial to the stable operation of the water chiller.
In some embodiments, the method comprises:
obtaining the frequency of the rotating speed of the compressor and the load shedding control quantity;
acquiring a differential pressure fluctuation control amount of the rotating speed of the compressor;
and adjusting the rotating speed of the compressor according to the frequency loading and unloading control quantity and the pressure difference fluctuation control quantity.
In some embodiments, the apparatus includes a processor and a memory storing program instructions configured to perform the above-described method for controlling a chiller, when the program instructions are executed.
In some embodiments, the water chiller includes the device for controlling a water chiller described above.
In some embodiments, the storage medium stores program instructions that, when executed, perform the method for controlling a chiller set described above.
The method and device for controlling the water chilling unit, the water chilling unit and the storage medium provided by the embodiment of the disclosure can realize the following technical effects:
in the embodiment of the disclosure, the frequency is controlled by the frequency converter, and the hysteresis existing in control is considered, so that the subsequent adjustment process of the rotating speed of the motor of the compressor is optimized. Meanwhile, the embodiment of the disclosure also considers the influence of the frequency fluctuation of the compressor on the oil return performance of the unit, and introduces corresponding control quantity by monitoring the fluctuation condition of the pressure difference of the air suction and the air discharge of the compressor, so that the adjustment of the rotating speed of the compressor is more accurate, and the stable operation of the water chilling unit is facilitated.
The foregoing general description and the following description are exemplary and explanatory only and are not restrictive of the application.
Drawings
One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which like reference numerals refer to similar elements, and in which:
FIG. 1 is a schematic diagram of a method for controlling a chiller according to an embodiment of the present disclosure;
FIG. 2 is a schematic illustration of another method for controlling a chiller provided by an embodiment of the present disclosure;
FIG. 3 is a schematic illustration of another method for controlling a chiller provided by an embodiment of the present disclosure;
FIG. 4 is a schematic illustration of another method for controlling a chiller provided by an embodiment of the present disclosure;
FIG. 5 is a schematic illustration of another method for controlling a chiller provided by an embodiment of the present disclosure;
fig. 6 is a schematic diagram of an apparatus for controlling a chiller according to an embodiment of the present disclosure.
Detailed Description
So that the manner in which the features and techniques of the disclosed embodiments can be understood in more detail, a more particular description of the embodiments of the disclosure, briefly summarized below, may be had by reference to the appended drawings, which are not intended to be limiting of the embodiments of the disclosure. In the following description of the technology, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be practiced without these details. In other instances, well-known structures and devices may be shown simplified in order to simplify the drawing.
The terms first, second and the like in the description and in the claims of the embodiments of the disclosure and in the above-described figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe embodiments of the present disclosure. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion.
The term "plurality" means two or more, unless otherwise indicated.
In the embodiment of the present disclosure, the character "/" indicates that the front and rear objects are an or relationship. For example, A/B represents: a or B.
The term "and/or" is an associative relationship that describes an object, meaning that there may be three relationships. For example, a and/or B, represent: a or B, or, A and B.
The term "corresponding" may refer to an association or binding relationship, and the correspondence between a and B refers to an association or binding relationship between a and B.
At present, a water chilling unit generally judges specific load conditions by calculating water temperature change, and controls a compressor by adopting a variable-frequency speed regulation method, so that continuous adjustment of cold energy is realized. And the prepared cold energy is transferred to the water body, so that the water temperature is always kept near the expected value.
But the control accuracy requirement of the related technology on the variable frequency speed regulation is higher. If the adjustment of the rotation speed of the compressor is controlled by only a simple up-down operation, the water temperature may be excessively adjusted due to the hysteresis of the water temperature change. And then causes frequent ascending and descending frequency of the compressor, which is unfavorable for the stable operation of the water chilling unit. Meanwhile, the variable frequency control of the compressor also affects the oil return effect of the unit. The frequent frequency rising and falling phenomenon of the compressor can further cause the phenomenon of oil leakage of the compressor, and the running stability of the water chilling unit is seriously affected.
Referring to fig. 1, an embodiment of the present disclosure provides a method for controlling a water chiller, including:
s101, the processor acquires the frequency of the rotating speed of the compressor and the load shedding control quantity.
S102, the processor acquires the pressure difference fluctuation control quantity of the rotating speed of the compressor.
S103, the processor adjusts the rotating speed of the compressor according to the frequency load-increasing and load-decreasing control quantity and the pressure difference fluctuation control quantity.
By adopting the method for controlling the water chilling unit, which is provided by the embodiment of the disclosure, the frequency is controlled by the frequency converter, and the hysteresis of the control is considered, so that the subsequent regulation process of the rotating speed of the motor of the compressor is optimized. Meanwhile, the embodiment of the disclosure also considers the influence of the frequency fluctuation of the compressor on the oil return performance of the unit, and introduces corresponding control quantity by monitoring the fluctuation condition of the pressure difference of the air suction and the air discharge of the compressor, so that the adjustment of the rotating speed of the compressor is more accurate, and the stable operation of the water chilling unit is facilitated.
Optionally, as shown in connection with fig. 2, the processor obtains a frequency-added load-shedding control amount of the rotation speed of the compressor, including:
s201, the processor acquires a PID regulating value of the rotating speed of the compressor corresponding to the frequency fluctuation.
S202, the processor determines an addition and subtraction load factor.
And S203, the processor determines the frequency load and unload control quantity of the rotating speed of the compressor according to the PID regulating value and the load and unload coefficient.
In this way, the embodiment of the disclosure can receive the frequency adjustment signal of the frequency converter and further optimize the subsequent adjustment process of the rotation speed of the compressor motor by using the PID algorithm. Meanwhile, by introducing the load and unload coefficient, the embodiment of the disclosure can reasonably correct the control quantity by combining the current working condition so as to avoid the excessive adjustment of the rotating speed of the compressor. Thereby facilitating more accurate control of the water temperature to be maintained around a desired value.
Optionally, the processor obtains a PID adjustment value of the rotational speed of the compressor corresponding to the frequency variation, including: the processor determines the frequency fluctuation; the processor determines a PID adjustment value of the compressor speed corresponding to the frequency variation according to an incremental PID algorithm. In this way, the embodiment of the disclosure can accurately control the adjustment process of the rotation speed of the compressor while adjusting the operation frequency of the compressor, so as to avoid the situation of excessive adjustment of the rotation speed. Therefore, the running frequency and the rotating speed of the compressor can be adapted, and the water temperature can be controlled to be kept near a desired value more accurately.
Optionally, the processor determining the frequency variation comprises: the processor receives the adjusting signal of the frequency converter and analyzes and obtains the frequency fluctuation. Thus, according to the working condition of the frequency converter, the embodiment of the disclosure can simply obtain the adjustment quantity of the running frequency of the compressor, so that the subsequent adjustment process of the rotating speed of the motor of the compressor can be reasonably controlled.
Optionally, the processor determines the frequency variation amount, including: the processor acquires the current water temperature and determines a set water temperature; the processor determines the target refrigerating capacity of the water chilling unit according to the current water temperature and the set water temperature; the processor determines the frequency variation amount according to the target cooling capacity. Thus, the embodiment of the disclosure can determine the refrigerating capacity of the water chilling unit by detecting the current water temperature, further judge the load condition of the unit, and reasonably control the operation frequency of the compressor to adjust. Thus, the embodiment of the disclosure can appropriately predict the frequency fluctuation amount in combination with the current water temperature, so that the adjustment process of the rotation speed of the compressor can be controlled more quickly. It is advantageous to control the water temperature to be maintained around a desired value more precisely.
Optionally, the processor determines the target refrigerating capacity of the water chiller according to the current water temperature and the set water temperature, including: processor calculates Q 1 ＝C p ×ρ×L×|T 1 -T s I, obtaining target refrigerating capacity Q of the water chilling unit 1 . Wherein C is p Specific heat of water, ρ is density of water, L is flow rate of water, T 1 T is the current water temperature s To set the water temperature. Thus, embodiments of the present disclosure may incorporate a heat calculation formula to determine the cooling capacity of the chiller. And then the load condition of the water chilling unit can be reasonably judged so as to more accurately control the running frequency of the compressor to adjust.
Optionally, the value range of the addition and subtraction load coefficient is [0, 10]. The load and unload coefficient can be selected according to the specific working condition of the water chilling unit so as to more accurately adjust the rotation speed of the compressor. Specifically, the value of the load and unload coefficient can be any value such as 0.5, 1 or 1.5.
Optionally, the processor determines an addition and subtraction load factor, including: the processor acquires the current water temperature; the processor determines the average rotating speed of the compressor in the load-reducing and load-reducing period; and the processor determines an acceleration and deceleration coefficient according to the current water temperature and the average rotating speed. In this way, the embodiment of the disclosure can identify the current working condition according to the current water temperature and the average rotation speed of the compressor in the load and unload period, and further can select a proper load and unload coefficient to correct the control quantity so as to avoid excessive regulation of the rotation speed of the compressor. Thereby facilitating more accurate control of the water temperature to be maintained around a desired value.
Optionally, the processor determines the load and unload coefficient according to the current water temperature and the average rotation speed, including: when the current water temperature is greater than or equal to the set water temperature and the average rotating speed is greater than the preset rotating speed, the processor determines that the load and unload coefficient is a first load and unload coefficient; or, when the current water temperature is greater than or equal to the set water temperature and the average rotation speed is less than or equal to the preset rotation speed, the processor determines that the load and unload coefficient is a second load and unload coefficient; or under the condition that the current water temperature is smaller than the set water temperature and the average rotating speed is larger than the preset rotating speed, the processor determines that the load and unload coefficient is a third load and unload coefficient; or, in the case that the current water temperature is less than the set water temperature and the average rotation speed is less than or equal to the preset rotation speed, the processor determines that the load-adding and load-reducing coefficient is the fourth load-adding and load-reducing coefficient. In this way, the embodiment of the disclosure can identify the current working condition according to the current water temperature and the average rotation speed of the compressor in the load and unload period, and further can select a proper load and unload coefficient to correct the control quantity so as to avoid excessive regulation of the rotation speed of the compressor. Thereby facilitating more accurate control of the water temperature to be maintained around a desired value.
Optionally, the processor determines a frequency load shedding control amount of the rotation speed of the compressor according to the PID adjustment value and the load shedding coefficient, including: the processor multiplies the PID regulating value and the load-reducing coefficient to obtain the frequency load-reducing control quantity of the rotating speed of the compressor. In this way, through the control of the frequency by the frequency converter, and taking into account the hysteresis of the control, the disclosed embodiments are able to further optimize the subsequent adjustment process of the compressor motor speed. Therefore, the rotation speed of the compressor is regulated more accurately, and the water temperature is controlled to be kept near a desired value more accurately.
Optionally, as shown in connection with fig. 3, the processor determines the load and unload coefficients, including:
s301, the processor acquires the current water temperature.
S302, the processor determines the average rotating speed of the compressor in the load and unload period.
S303, determining the load and unload coefficient as a first load and unload coefficient by the processor when the current water temperature is greater than or equal to the set water temperature and the average rotating speed is greater than the preset rotating speed.
S304, determining that the load and unload coefficient is a second load and unload coefficient by the processor under the condition that the current water temperature is greater than or equal to the set water temperature and the average rotating speed is less than or equal to the preset rotating speed.
S305, determining that the load and unload coefficient is a third load and unload coefficient by the processor when the current water temperature is smaller than the set water temperature and the average rotating speed is larger than the preset rotating speed.
S306, determining that the loading and unloading coefficient is a fourth loading and unloading coefficient by the processor under the condition that the current water temperature is smaller than the set water temperature and the average rotating speed is smaller than or equal to the preset rotating speed.
In this way, the embodiment of the disclosure can identify the current working condition according to the current water temperature and the average rotation speed of the compressor in the load and unload period, and further can select a proper load and unload coefficient to correct the control quantity so as to avoid excessive regulation of the rotation speed of the compressor. Thereby facilitating more accurate control of the water temperature to be maintained around a desired value.
Optionally, the duration of the addition and subtraction period is in the range of [1s,30s ]. The duration of the load adding and subtracting period can be selected according to the specific working condition of the water chilling unit so as to obtain the actual rotation speed of the compressor more accurately. Preferably, the duration of the addition and subtraction load period may be set to 5s.
Specifically, the first load-adding and load-reducing coefficient is smaller than the second load-adding and load-reducing coefficient. Therefore, when the current water temperature is greater than or equal to the set water temperature, the unit is indicated to enter a loading working condition, and the average rotating speed of the compressor in the load and unload period is further identified. If the average rotation speed is larger, a slightly smaller first load-reducing coefficient is selected to properly reduce the increase of the rotation speed. Otherwise, if the average rotation speed is smaller, a second larger load-reducing coefficient is selected to properly increase the rotation speed. The embodiments of the present disclosure are capable of more accurately adjusting the compressor motor speed, thereby facilitating more accurate control of water temperature maintenance around a desired value.
Specifically, in some embodiments, after multiple experimental tests verify that the first loading and unloading coefficient may be set to 0.6, and the second loading and unloading coefficient may be set to 1.0.
Specifically, the third addition and subtraction load factor is larger than the fourth addition and subtraction load factor. Therefore, when the current water temperature is smaller than the set water temperature, the unit is indicated to enter the load shedding working condition, and the average rotating speed of the compressor in the load shedding period is further identified. If the average rotation speed is larger, a third larger load-reducing coefficient is selected to properly increase the rotation speed. Otherwise, if the average rotation speed is smaller, a fourth smaller load-reducing coefficient is selected to properly reduce the rotation speed. The embodiments of the present disclosure are capable of more accurately adjusting the compressor motor speed, thereby facilitating more accurate control of water temperature maintenance around a desired value.
Specifically, in some embodiments, after multiple experimental tests verify that the third loading and unloading coefficient may be set to 0.8, and the second loading and unloading coefficient may be set to 0.6.
Optionally, as shown in conjunction with fig. 4, the processor obtains a differential pressure fluctuation control amount of the rotation speed of the compressor, including:
s401, the processor acquires the pressure difference change rate within the set period.
S402, the processor determines a differential pressure influence coefficient.
S403, the processor determines the differential pressure fluctuation control quantity of the rotating speed of the compressor according to the differential pressure change rate and the differential pressure influence coefficient.
In this way, the embodiment of the disclosure can consider the influence of the compressor frequency variation on the unit oil return performance by monitoring the pressure difference change rate in the set period. Through the fluctuation condition of monitoring compressor suction and exhaust pressure difference to introduce corresponding control quantity, the embodiment of the disclosure can make the regulation of compressor rotational speed more accurate, thereby can avoid excessive regulation to cause the compressor to appear the phenomenon of oil leakage, be favorable to the steady operation of cooling water set.
Optionally, the processor acquires a pressure difference change rate within a set period of time, including: the processor continuously monitors the suction pressure and the discharge pressure of the compressor, calculates the difference value between the suction pressure and the discharge pressure, and obtains a real-time pressure difference; the processor determines a first real-time pressure difference for setting a starting point of the period and a second real-time pressure difference for setting an ending point of the period; the processor obtains the pressure difference change rate in a set period according to the first real-time pressure difference and the second real-time pressure difference. In this way, the embodiment of the disclosure continuously monitors the difference value between the suction pressure and the exhaust pressure, namely the real-time differential pressure, and further obtains the change condition of the real-time differential pressure in a set period, so that the fluctuation condition of the oil return performance of the unit can be accurately judged.
Optionally, the duration of the set period is in the range of [1s,60s ]. The duration of the set period can be selected according to the specific working condition of the water chilling unit so as to more accurately acquire the change condition of the suction and exhaust pressure difference of the compressor. Preferably, the duration of the set period may be set to 10s. Meanwhile, the set period end corresponds to a time node for acquiring the current water temperature. Thereby improving the consistency of the regulation and control of the frequency load and unload control quantity and the pressure difference fluctuation control quantity.
Optionally, the processor obtains a pressure difference change rate in a set period according to the first real-time pressure difference and the second real-time pressure difference, including: the processor subtracts the first real-time differential pressure from the second real-time differential pressure to obtain a differential pressure difference; the processor divides the differential pressure difference value by the duration of the set period to obtain the differential pressure change rate in the set period. In this way, the embodiment of the disclosure can monitor the change condition of the suction and exhaust pressure difference before and after the set period, and properly adjust the rotation speed of the compressor by utilizing the calculated pressure difference change rate, so that the oil return performance of the unit does not have larger fluctuation. Therefore, the phenomenon of oil leakage of the compressor can be avoided, and the stable operation of the water chilling unit is facilitated.
Specifically, when the pressure difference change rate is a positive value, it indicates that the suction-exhaust pressure difference gradually decreases in the set period, and at this time, the oil return performance of the unit becomes poor. By introducing the pressure difference fluctuation control quantity, and the control quantity is positive corresponding to the pressure difference change rate, the embodiment of the disclosure can properly increase the rotation speed of the compressor, thereby improving the oil return effect of the unit and being beneficial to the stable operation of the water chilling unit. On the contrary, when the pressure difference change rate is negative, the suction and exhaust pressure difference gradually becomes larger in the set period, and the oil return effect of the unit is improved. By introducing the pressure difference fluctuation control quantity, and the control quantity is also negative corresponding to the pressure difference change rate, the embodiment of the disclosure can properly reduce the rotating speed of the compressor, thereby avoiding the oil leakage phenomenon of the compressor and being beneficial to the stable operation of the water chilling unit.
Optionally, the differential pressure influence coefficient has a value in the range of [0, 10]. The differential pressure influence coefficient can be selected according to the specific working condition of the water chilling unit so as to more accurately adjust the rotating speed of the compressor. Preferably, the differential pressure influence coefficient may be set to 2.
Optionally, the processor determines a differential pressure fluctuation control amount of the rotation speed of the compressor according to the differential pressure change rate and the differential pressure influence coefficient, and the method comprises the following steps: the processor multiplies the pressure difference change rate and the pressure difference influence coefficient to obtain the pressure difference fluctuation control quantity of the rotating speed of the compressor. In this way, the embodiment of the disclosure can consider the influence of the compressor frequency variation on the unit oil return performance by monitoring the pressure difference change rate in the set period. Through the fluctuation condition of monitoring compressor suction and exhaust pressure difference to introduce corresponding control quantity, the embodiment of the disclosure can make the regulation of compressor rotational speed more accurate, thereby can avoid excessive regulation to cause the compressor to appear the phenomenon of oil leakage, be favorable to the steady operation of cooling water set.
Optionally, the processor adjusts the rotation speed of the compressor according to the frequency load-increasing and load-decreasing control amount and the pressure difference fluctuation control amount, including: the processor determines the current rotating speed of the compressor; the processor adds the frequency load-reducing control quantity and the pressure difference fluctuation control quantity to obtain a total control quantity, and multiplies the total control quantity by a rotating speed value corresponding to the unit control quantity to obtain a rotating speed adjusting value of the compressor; the processor obtains the target rotating speed of the compressor according to the current rotating speed and the rotating speed adjusting value, and controls the compressor to operate according to the target rotating speed. In this way, by acquiring the frequency load/unload control amount and the pressure difference fluctuation control amount, the embodiments of the present disclosure can predict, from multiple aspects, the influence that the regulation and control process may have on the running stability of the chiller, so that the rotation speed of the compressor can be regulated more accurately. On one hand, the water temperature can be controlled to be maintained near an expected value more accurately, and on the other hand, the stable operation of the water chilling unit is facilitated.
Optionally, the processor obtains the target rotation speed of the compressor according to the current rotation speed and the rotation speed adjustment value, including: the processor adds the current rotation speed to the rotation speed adjustment value to obtain a target rotation speed of the compressor. In this way, the embodiments of the present disclosure can simply and directly acquire the target rotation speed of the compressor. By controlling the compressor to run at the target rotational speed, the embodiment of the disclosure can more accurately control the water temperature to be maintained near the expected value, and is beneficial to the stable running of the water chilling unit.
Optionally, the processor obtains the target rotation speed of the compressor according to the current rotation speed and the rotation speed adjustment value, including: under the condition that the rotating speed adjusting value is larger than the upper limit value of the preset regulating section, the processor adds the current rotating speed and the upper limit value of the preset regulating section to obtain the target rotating speed of the compressor; or under the condition that the rotation speed adjustment value is smaller than or equal to the upper limit value of the preset regulation and control interval and is larger than or equal to the lower limit value of the preset regulation and control interval, the processor adds the current rotation speed and the rotation speed adjustment value to obtain the target rotation speed of the compressor; or under the condition that the rotation speed adjustment value is smaller than the lower limit value of the preset regulation and control interval, the processor adds the current rotation speed and the lower limit value of the preset regulation and control interval to obtain the target rotation speed of the compressor. Thus, by comparing the rotation speed adjustment value with the preset adjustment interval, the embodiment of the disclosure can reasonably control the increase or decrease of the rotation speed of the compressor motor. When the rotation speed adjusting value exceeds a preset adjusting and controlling interval, the embodiment of the disclosure adjusts and controls according to the preset adjusting amplitude, so that the condition that water temperature fluctuation is large or the unit operation is unstable due to overlarge adjusting force can be avoided.
Optionally, as shown in connection with fig. 5, the processor adjusts the rotational speed of the compressor according to the frequency load/unload control amount and the pressure difference fluctuation control amount, including:
s501, the processor determines the current rotational speed of the compressor.
S502, the processor adds the frequency load-reducing control quantity and the pressure difference fluctuation control quantity to obtain a total control quantity, and multiplies the total control quantity by a rotating speed value corresponding to the unit control quantity to obtain a rotating speed adjusting value of the compressor.
S503, under the condition that the rotation speed adjustment value is larger than the upper limit value of the preset regulation and control interval, the processor adds the current rotation speed and the upper limit value of the preset regulation and control interval to obtain the target rotation speed of the compressor.
S504, under the condition that the rotation speed adjustment value is smaller than or equal to the upper limit value of the preset regulation section and is larger than or equal to the lower limit value of the preset regulation section, the processor adds the current rotation speed and the rotation speed adjustment value to obtain the target rotation speed of the compressor.
And S505, under the condition that the rotation speed adjustment value is smaller than the lower limit value of the preset regulation and control interval, the processor adds the current rotation speed and the lower limit value of the preset regulation and control interval to obtain the target rotation speed of the compressor.
S506, the processor controls the compressor to operate according to the target rotating speed.
In this way, by acquiring the frequency load/unload control amount and the pressure difference fluctuation control amount, the embodiments of the present disclosure can predict, from multiple aspects, the influence that the regulation and control process may have on the running stability of the chiller, so that the rotation speed of the compressor can be regulated more accurately. On one hand, the water temperature can be controlled to be maintained near an expected value more accurately, and on the other hand, the stable operation of the water chilling unit is facilitated. Meanwhile, the rotation speed adjusting value is compared with a preset adjusting and controlling interval, and the embodiment of the disclosure can reasonably control the increase or decrease of the rotation speed of the compressor motor. When the rotation speed adjusting value exceeds a preset adjusting and controlling interval, the embodiment of the disclosure adjusts and controls according to the preset adjusting amplitude, so that the condition that water temperature fluctuation is large or the unit operation is unstable due to overlarge adjusting force can be avoided.
As shown in connection with fig. 6, an embodiment of the present disclosure provides an apparatus for controlling a chiller, including a processor (processor) 601 and a memory (memory) 602. Optionally, the apparatus may further comprise a communication interface (Communication Interface) 603 and a bus 604. The processor 601, the communication interface 603, and the memory 602 may communicate with each other via the bus 604. The communication interface 603 may be used for information transfer. Processor 601 may invoke logic instructions in memory 602 to perform the method for controlling a chiller in accordance with the above-described embodiments.
Further, the logic instructions in the memory 602 described above may be implemented in the form of software functional units and may be stored in a computer-readable storage medium when sold or used as a stand-alone product.
The memory 602 is a computer readable storage medium that can be used to store a software program, a computer executable program, such as program instructions/modules corresponding to the methods in the embodiments of the present disclosure. The processor 601 executes the program instructions/modules stored in the memory 602 to perform functional applications and data processing, i.e., to implement the method for controlling a chiller in the above-described embodiments.
The memory 602 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, at least one application program required for a function; the storage data area may store data created according to the use of the terminal device, etc. In addition, the memory 602 may include high-speed random access memory, and may also include non-volatile memory.
The embodiment of the disclosure provides a water chilling unit, which comprises the device for controlling the water chilling unit.
The embodiment of the disclosure provides a storage medium, which stores computer executable instructions, wherein the computer executable instructions execute the method for controlling the water chiller when in operation.
The storage medium may be a transitory computer readable storage medium or a non-transitory computer readable storage medium.
Embodiments of the present disclosure may be embodied in a software product stored on a storage medium, including one or more instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of a method according to embodiments of the present disclosure. And the aforementioned storage medium may be a non-transitory storage medium including: a plurality of media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or a transitory storage medium.
The above description and the drawings illustrate embodiments of the disclosure sufficiently to enable those skilled in the art to practice them. Other embodiments may involve structural, logical, electrical, process, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in, or substituted for, those of others. Moreover, the terminology used in the present application is for the purpose of describing embodiments only and is not intended to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a," "an," and "the" (the) are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and/or" as used in this application is meant to encompass any and all possible combinations of one or more of the associated listed. Furthermore, when used in this application, the terms "comprises," "comprising," and/or "includes," and variations thereof, mean that the stated features, integers, steps, operations, elements, and/or components are present, but that the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof is not precluded. Without further limitation, an element defined by the phrase "comprising one …" does not exclude the presence of other like elements in a process, method or apparatus comprising such elements. In this context, each embodiment may be described with emphasis on the differences from the other embodiments, and the same similar parts between the various embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method sections disclosed in the embodiments, the description of the method sections may be referred to for relevance.
Those of skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. The skilled artisan may use different methods for each particular application to achieve the described functionality, but such implementation should not be considered to be beyond the scope of the embodiments of the present disclosure. It will be clearly understood by those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.
In the embodiments disclosed herein, the disclosed methods, articles of manufacture (including but not limited to devices, apparatuses, etc.) may be practiced in other ways. For example, the apparatus embodiments described above are merely illustrative, and for example, the division of the units may be merely a logical function division, and there may be additional divisions when actually implemented, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. In addition, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form. The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to implement the present embodiment. In addition, each functional unit in the embodiments of the present disclosure may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.
The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. In the description corresponding to the flowcharts and block diagrams in the figures, operations or steps corresponding to different blocks may also occur in different orders than that disclosed in the description, and sometimes no specific order exists between different operations or steps. For example, two consecutive operations or steps may actually be performed substantially in parallel, they may sometimes be performed in reverse order, which may be dependent on the functions involved. Each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Claims (9)

1. A method for controlling a chiller, comprising:
obtaining the frequency of the rotating speed of the compressor and the load shedding control quantity;
acquiring a differential pressure fluctuation control amount of the rotating speed of the compressor;
according to the frequency loading and unloading control quantity and the pressure difference fluctuation control quantity, the rotating speed of the compressor is regulated;
the obtaining the frequency of the rotating speed of the compressor and the load-shedding control quantity comprises the following steps: acquiring a PID regulating value of the rotating speed of the compressor corresponding to the frequency fluctuation; determining an addition and subtraction load factor; determining the frequency load-reducing control quantity of the rotating speed of the compressor according to the PID regulating value and the load-reducing coefficient;
the obtaining the differential pressure fluctuation control amount of the rotating speed of the compressor comprises the following steps: acquiring the pressure difference change rate in a set period; determining a differential pressure influence coefficient; and determining the differential pressure fluctuation control quantity of the rotating speed of the compressor according to the differential pressure change rate and the differential pressure influence coefficient.
2. The method of claim 1, wherein the determining the load factor comprises:
acquiring the current water temperature;
determining the average rotating speed of the compressor in the load-reducing and load-reducing period;
and determining the load and unload coefficient according to the current water temperature and the average rotation speed.
3. The method of claim 2, wherein determining the load and unload coefficient based on the current water temperature and the average rotational speed comprises:
determining the load and unload coefficient as a first load and unload coefficient under the condition that the current water temperature is greater than or equal to the set water temperature and the average rotating speed is greater than the preset rotating speed; or,
determining that the load-adding and load-reducing coefficient is a second load-adding and load-reducing coefficient under the condition that the current water temperature is greater than or equal to the set water temperature and the average rotating speed is less than or equal to the preset rotating speed; or,
under the condition that the current water temperature is smaller than the set water temperature and the average rotating speed is larger than the preset rotating speed, determining that the load-adding and unload coefficient is a third load-adding and unload coefficient; or,
and determining the load and unload coefficient as a fourth load and unload coefficient under the condition that the current water temperature is smaller than the set water temperature and the average rotating speed is smaller than or equal to the preset rotating speed.
4. The method of claim 1, wherein the obtaining the rate of change of the differential pressure over the set period of time comprises:
continuously monitoring the suction pressure and the discharge pressure of the compressor, and calculating the difference value between the suction pressure and the discharge pressure to obtain a real-time pressure difference;
determining a first real-time differential pressure at the beginning of the set period and a second real-time differential pressure at the end of the set period;
and acquiring the pressure difference change rate in a set period according to the first real-time pressure difference and the second real-time pressure difference.
5. The method according to any one of claims 1 to 4, wherein the adjusting the rotation speed of the compressor according to the frequency load reducing control amount and the pressure difference fluctuation control amount includes:
determining a current rotational speed of the compressor;
adding the frequency loading and unloading control quantity and the pressure difference fluctuation control quantity to obtain a total control quantity, and multiplying the total control quantity by a rotating speed value corresponding to the unit control quantity to obtain a rotating speed adjustment value of the compressor;
and obtaining the target rotating speed of the compressor according to the current rotating speed and the rotating speed adjusting value, and controlling the compressor to operate according to the target rotating speed.
6. The method of claim 5, wherein obtaining the target rotational speed of the compressor based on the current rotational speed and the rotational speed adjustment value comprises:
under the condition that the rotating speed adjusting value is larger than the upper limit value of the preset regulating and controlling interval, adding the current rotating speed and the upper limit value of the preset regulating and controlling interval to obtain the target rotating speed of the compressor; or,
under the condition that the rotation speed adjustment value is smaller than or equal to the upper limit value of the preset regulation and control interval and is larger than or equal to the lower limit value of the preset regulation and control interval, adding the current rotation speed and the rotation speed adjustment value to obtain the target rotation speed of the compressor; or,
and under the condition that the rotating speed adjusting value is smaller than the lower limit value of the preset regulating and controlling interval, adding the current rotating speed and the lower limit value of the preset regulating and controlling interval to obtain the target rotating speed of the compressor.
7. An apparatus for controlling a water chiller comprising a processor and a memory storing program instructions, wherein the processor is configured to perform the method for controlling a water chiller as claimed in any one of claims 1 to 6 when the program instructions are run.
8. A chiller plant comprising the apparatus for controlling a chiller plant of claim 7.
9. A storage medium storing program instructions which, when executed, perform the method for controlling a chiller as claimed in any one of claims 1 to 6.
CN202211034760.5A 2022-08-26 2022-08-26 Method and device for controlling water chilling unit, water chilling unit and storage medium Active CN115355640B (en)

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Publication number Priority date Publication date Assignee Title
JP2011241760A (en) * 2010-05-18 2011-12-01 Mitsubishi Heavy Ind Ltd Motor-driven compressor, heat source machine, and method of controlling the heat source machine
CN104903660A (en) * 2012-12-28 2015-09-09 大金工业株式会社 Refrigeration device
CN111473466A (en) * 2020-04-21 2020-07-31 宁波奥克斯电气股份有限公司 Frequency control method and air conditioner
CN112432342A (en) * 2020-11-23 2021-03-02 珠海格力电器股份有限公司 Differential pressure control system and method of heat pump air conditioner and heat pump air conditioner
KR20220009052A (en) * 2020-07-15 2022-01-24 엘지전자 주식회사 Chiller system and method for operating the same
CN217236154U (en) * 2022-02-25 2022-08-19 青岛海尔智能技术研发有限公司 Refrigerating system and refrigerator

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011241760A (en) * 2010-05-18 2011-12-01 Mitsubishi Heavy Ind Ltd Motor-driven compressor, heat source machine, and method of controlling the heat source machine
CN104903660A (en) * 2012-12-28 2015-09-09 大金工业株式会社 Refrigeration device
CN111473466A (en) * 2020-04-21 2020-07-31 宁波奥克斯电气股份有限公司 Frequency control method and air conditioner
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