CN117529065A - Control method and device, cooling system, frequency converter and frequency converter unit - Google Patents
Control method and device, cooling system, frequency converter and frequency converter unit Download PDFInfo
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- CN117529065A CN117529065A CN202410009062.2A CN202410009062A CN117529065A CN 117529065 A CN117529065 A CN 117529065A CN 202410009062 A CN202410009062 A CN 202410009062A CN 117529065 A CN117529065 A CN 117529065A
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- 238000001816 cooling Methods 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims abstract description 40
- 230000017525 heat dissipation Effects 0.000 claims abstract description 34
- 238000004364 calculation method Methods 0.000 claims description 3
- 239000003507 refrigerant Substances 0.000 abstract description 57
- 238000006243 chemical reaction Methods 0.000 abstract description 5
- 230000001105 regulatory effect Effects 0.000 abstract description 2
- 230000033228 biological regulation Effects 0.000 abstract 1
- 230000007423 decrease Effects 0.000 description 6
- 230000005855 radiation Effects 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004378 air conditioning Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2089—Modifications to facilitate cooling, ventilating, or heating for power electronics, e.g. for inverters for controlling motor
- H05K7/20945—Thermal management, e.g. inverter temperature control
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2029—Modifications to facilitate cooling, ventilating, or heating using a liquid coolant with phase change in electronic enclosures
- H05K7/20309—Evaporators
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2029—Modifications to facilitate cooling, ventilating, or heating using a liquid coolant with phase change in electronic enclosures
- H05K7/20318—Condensers
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2029—Modifications to facilitate cooling, ventilating, or heating using a liquid coolant with phase change in electronic enclosures
- H05K7/20327—Accessories for moving fluid, for connecting fluid conduits, for distributing fluid or for preventing leakage, e.g. pumps, tanks or manifolds
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2089—Modifications to facilitate cooling, ventilating, or heating for power electronics, e.g. for inverters for controlling motor
- H05K7/20936—Liquid coolant with phase change
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- 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)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Power Engineering (AREA)
- Cooling Or The Like Of Electrical Apparatus (AREA)
Abstract
The invention provides a control method, a control device, a cooling system, a frequency converter and a frequency converter unit, and relates to the technical field of frequency conversion air conditioners. The cooling system comprises a heat-dissipating cold plate, a temperature sensor and an electronic expansion valve, wherein the heat-dissipating cold plate is provided with an inlet and an outlet, and the electronic expansion valve is arranged at the outlet of the heat-dissipating cold plate. The control method comprises the following steps: acquiring the inlet temperature and the outlet temperature of a heat dissipation cold plate; calculating the difference between the outlet temperature and the inlet temperature according to the acquired inlet temperature and outlet temperature to obtain an original temperature difference; and adjusting the opening of the electronic expansion valve according to the original temperature difference. The opening degree of the electronic expansion valve is regulated according to the original temperature difference, so that the regulation of the refrigerant flow is realized, the temperature of the heat dissipation cold plate does not need to be considered, the influence of working conditions is avoided, the control is simple, the response is sensitive, the temperature target value does not need to be modified along with the working conditions, and the product with changeable working conditions can be well adapted.
Description
Technical Field
The invention relates to the technical field of variable frequency air conditioners, in particular to a control method, a control device, a cooling system, a frequency converter and a frequency converter unit.
Background
In the large-scale refrigeration air conditioning industry, the use of frequency conversion units has become a trend, and frequency converters are an indispensable part in the frequency conversion units. The frequency converter generates a lot of heat during operation and must be cooled. Compared with the conventional air cooling and water cooling heat dissipation modes, if the heat dissipation cold plate of the frequency converter is directly cooled by the refrigerant of the frequency converter unit, the heat dissipation device has the advantages of high heat dissipation efficiency, fewer auxiliary facilities, high reliability, low running noise and the like.
When the cooling plate of the frequency converter is directly cooled by the refrigerant of the frequency converter unit, the flow of the refrigerant needs to be controlled. The heat-generating element is prevented from being damaged due to the fact that the temperature of the cold plate is too high due to insufficient refrigerant flow; and the excessive refrigerant is avoided to be introduced, so that the economy of the system is reduced. An electronic expansion valve is generally arranged at the outlet or inlet of the heat-dissipating cold plate, and the opening degree of the electronic expansion valve is regulated by a certain algorithm to reduce the pressure and throttle the refrigerant, so as to control the temperature of the cold plate.
The common practice is to set a target value of the temperature of the cold plate, and a closed-loop control method based on the deviation of the target temperature and the actual temperature, such as fuzzy control, fuzzy PID and the like, is adopted. However, this method is greatly affected by the working conditions in practical application. In order to cope with the working condition changes, different temperature target values can be set only for different working conditions. In the actual running process of the product, the working condition may change at any time, and it is not practical to match the working condition by modifying the temperature target value.
Therefore, the existing control method cannot be adapted to products with variable working conditions.
Disclosure of Invention
In order to solve the problem that the control method in the prior art cannot be suitable for products with variable working conditions, one of the purposes of the invention is to provide a control method.
The invention provides the following technical scheme:
a control method of a cooling system, the cooling system comprising a heat-dissipating cold plate, a temperature sensor and an electronic expansion valve, the heat-dissipating cold plate having an inlet and an outlet, the electronic expansion valve being disposed at the outlet of the heat-dissipating cold plate;
the control method comprises the following steps:
acquiring the inlet temperature and the outlet temperature of the heat dissipation cold plate;
calculating the difference between the outlet temperature and the inlet temperature according to the acquired inlet temperature and outlet temperature to obtain an original temperature difference;
and adjusting the opening of the electronic expansion valve according to the original temperature difference.
As a further alternative to the control method, the step of adjusting the opening degree of the electronic expansion valve according to the original temperature difference includes:
obtaining control deviation according to a temperature interval where the original temperature difference is located;
and adjusting the opening degree of the electronic expansion valve according to the control deviation.
As a further alternative to the control method, the step of obtaining the control deviation according to the temperature interval in which the original temperature difference is located includes:
if the original temperature difference is smaller than or equal to a first preset value, calculating a difference value between the original temperature difference and the first preset value to obtain the control deviation;
if the original temperature difference is larger than the first preset value and smaller than the second preset value, the control deviation is equal to zero;
if the original temperature difference is larger than or equal to the second preset value, calculating a difference value between the original temperature difference and the second preset value to obtain the control deviation;
wherein the first preset value is smaller than the second preset value.
As a further alternative to the control method, the step of adjusting the opening degree of the electronic expansion valve according to the control deviation includes:
if the control deviation is smaller than zero, reducing the opening of the electronic expansion valve;
and if the control deviation is larger than zero, increasing the opening degree of the electronic expansion valve.
As a further alternative to the control method, before the step of adjusting the opening degree of the electronic expansion valve according to the original temperature difference, the method further includes:
calculating a maximum temperature, the maximum temperature being equal to the greater of the inlet temperature and the outlet temperature;
judging whether the highest temperature is larger than a third preset value or not;
if the highest temperature is greater than the third preset value, increasing the opening of the electronic expansion valve;
and if the highest temperature is not greater than the third preset value, adjusting the opening of the electronic expansion valve according to the original temperature difference.
Another object of the present invention is to provide a control device for a cooling system.
The invention provides the following technical scheme:
a control device of a cooling system, the cooling system comprising a heat-dissipating cold plate, a temperature sensor and an electronic expansion valve, the heat-dissipating cold plate having an inlet and an outlet, the electronic expansion valve being disposed at the outlet of the heat-dissipating cold plate;
the control device includes:
the information acquisition module is used for acquiring the inlet temperature and the outlet temperature of the heat dissipation cold plate;
the calculation module is used for calculating the difference value between the outlet temperature and the inlet temperature according to the acquired inlet temperature and outlet temperature to obtain an original temperature difference;
and the control module is used for adjusting the opening of the electronic expansion valve according to the original temperature difference.
It is a further object of the invention to provide a cooling system.
The invention provides the following technical scheme:
a cooling system, comprising:
a controller for executing the control method;
a heat-dissipating cold plate having an inlet and an outlet;
a temperature sensor; and
and the electronic expansion valve is arranged at the outlet of the heat dissipation cold plate.
It is a further object of the invention to provide a frequency converter.
The invention provides the following technical scheme:
a frequency converter comprises a heating unit and the cooling system, wherein the heating unit is arranged on the heat dissipation cold plate.
It is a further object of the invention to provide a frequency converter assembly.
The invention provides the following technical scheme:
a frequency converter unit comprises a condenser, an evaporator and the frequency converter;
the outlet of the condenser is communicated with the inlet of the heat dissipation cold plate, and the inlet of the evaporator is communicated with the outlet of the heat dissipation cold plate through the electronic expansion valve.
The embodiment of the invention has the following beneficial effects:
in the running process of the cooling system, if the flow of the refrigerant is sufficient, the liquid refrigerant in the heat dissipation cold plate is more. At this time, the pressure of the refrigerant determines the phase transition temperature of the refrigerant, and thus the temperature of the heat-dissipating cold plate. On the basis, the opening degree of the electronic expansion valve connected with the outlet of the heat dissipation cold plate is reduced, so that the pressure in the heat dissipation cold plate is increased, and the phase change temperature of the refrigerant is slightly increased. In other words, in a large opening range, the flow rate of the refrigerant becomes small, but the temperature of the heat radiation cooling plate is slightly raised, and the heat radiation cooling plate is in a stable state. Meanwhile, since the inlet pressure of the heat-dissipating cold plate is higher than the outlet pressure, the inlet temperature of the heat-dissipating cold plate is higher than the outlet temperature.
Conversely, if the flow rate of the refrigerant is insufficient, the cooling plate has more gaseous refrigerant. Small bubbles formed by the gaseous refrigerant and the liquid refrigerant are randomly contacted with the heat dissipation cold plate, so that the equivalent heat exchange coefficient of the heat dissipation cold plate is changed rapidly, the temperature of the heat dissipation cold plate is fluctuated severely, the temperatures of different areas are inconsistent, and the temperature uniformity is poor. At this time, as the refrigerant flow decreases, the content of the gaseous refrigerant in the outlet refrigerant of the heat-dissipating cold plate starts to increase, so that the equivalent heat exchange coefficient of the outlet of the heat-dissipating cold plate decreases, and the outlet temperature of the heat-dissipating cold plate increases continuously. When the flow of the refrigerant is reduced to a certain degree, the outlet temperature of the heat dissipation cold plate exceeds the inlet temperature.
Based on the principle, the control method calculates the original temperature difference according to the inlet temperature and the outlet temperature of the heat-dissipating cold plate, the state of the refrigerant in the heat-dissipating cold plate is intuitively reflected by the original temperature difference, and then the opening degree of the electronic expansion valve is adjusted according to the original temperature difference, so that the adjustment of the refrigerant flow is realized, the temperature of the heat-dissipating cold plate is not needed to be considered, the influence of working conditions is avoided, and the control method can be well adapted to products with changeable working conditions.
In order to make the above objects, features and advantages of the present invention more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view showing the overall structure of a cooling system according to an embodiment of the present invention;
FIG. 2 shows a graph of heat sink cold plate temperature as a function of electronic expansion valve opening;
FIG. 3 is a schematic diagram illustrating steps of a control method according to an embodiment of the present invention;
fig. 4 shows a flowchart of step S3 in a control method according to an embodiment of the present invention;
fig. 5 shows a flowchart of step S31 in a control method according to an embodiment of the present invention;
fig. 6 shows a flowchart of step S32 in a control method according to an embodiment of the present invention;
FIG. 7 shows a block diagram of an original PID closed-loop control of temperature difference in a control method according to an embodiment of the invention;
FIG. 8 is a flowchart showing a step S2' in a control method according to an embodiment of the present invention;
FIG. 9 is a flow chart of a control method according to an embodiment of the present invention;
fig. 10 shows a block diagram of a control device according to an embodiment of the present invention.
Description of main reference numerals:
100-frequency converter; 110-a cooling system; 111-a controller; 112-a heat-dissipating cold plate; 113-a temperature sensor; 114-an electronic expansion valve; 120-heating units; 200-condenser; 300-evaporator;
10-an information acquisition module; a 20-calculation module; 30-control module.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the templates herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
Examples
Referring to fig. 1, the present embodiment provides a cooling system 110, specifically a cooling system for a frequency converter refrigerant, where the cooling system 110 includes a controller 111, a heat dissipation cold plate 112, a temperature sensor 113 and an electronic expansion valve 114.
Wherein the inlet and outlet of the heat-dissipating cold plate 112 are provided with temperature sensors 113, respectively. The temperature sensor 113 at the inlet of the heat-dissipating cold plate 112 is located at the inlet temperature T of the heat-dissipating cold plate 112 in Measuring the outlet temperature T of the cold plate 112 by a temperature sensor 113 at the outlet of the cold plate 112 out Measurements were made.
The temperature sensors 113 are electrically connected to the controller 111, and transmit inlet temperature information and outlet temperature information of the heat-dissipating cold plate 112 to the controller 111, respectively.
In addition, an electronic expansion valve 114 is disposed at an outlet of the heat-dissipating cold plate 112 and electrically connected to the controller 111. In use, the controller 111 adjusts the opening of the electronic expansion valve 114, thereby adjusting the flow rate of the refrigerant.
Referring to fig. 2, in the operation process of the cooling system 110, if the flow rate of the cooling medium is sufficient, the liquid cooling medium in the heat dissipation cooling plate 112 is more. At this time, the pressure of the refrigerant determines the phase transition temperature of the refrigerant, and thus the temperature of the heat radiation cold plate 112. On this basis, the opening degree of the electronic expansion valve 114 connected to the outlet of the heat radiation cold plate 112 is reduced, so that the pressure in the heat radiation cold plate 112 increases, and the phase transition temperature of the refrigerant slightly increases. In other words, when the opening degree of the electronic expansion valve 114 is adjusted from the maximum to the minimum, the flow rate of the refrigerant is reduced in a large opening degree range, but the temperature of the heat radiation cooling plate 112 is slightly increased, and the temperature is in a stable state, which is called a "stable stage". Meanwhile, since the inlet pressure of the heat dissipating cold plate 112 is higher than the outlet pressure, the inlet temperature of the heat dissipating cold plate 112 is higher than the outlet temperature.
As the opening of the electronic expansion valve 114 continues to decrease and passes a certain critical opening, the flow rate of the refrigerant is relatively insufficient, and the gaseous refrigerant in the heat-dissipating cold plate 112 is more. Small bubbles formed by the gaseous refrigerant and the liquid refrigerant are randomly contacted with the heat dissipation cold plate 112, so that the equivalent heat exchange coefficient of the heat dissipation cold plate 112 changes sharply, the temperature of the heat dissipation cold plate 112 fluctuates sharply, the temperatures of different areas are inconsistent, and the temperature uniformity is poor, which is called as an oscillation section. At this time, as the refrigerant flow decreases, the content of the gaseous refrigerant in the outlet refrigerant of the heat-dissipating cold plate 112 starts to increase, so that the equivalent heat exchange coefficient of the outlet of the heat-dissipating cold plate 112 decreases, and the outlet temperature of the heat-dissipating cold plate 112 increases continuously. When the flow rate of the refrigerant is reduced to a certain level, the outlet temperature of the heat dissipating cold plate 112 exceeds the inlet temperature.
Based on the above principle, the original temperature difference is calculated according to the inlet temperature and the outlet temperature of the heat-dissipating cold plate 112, so that the state of the refrigerant in the heat-dissipating cold plate 112 can be intuitively reflected by using the original temperature difference. When the liquid refrigerant in the heat-dissipating cold plate 112 is more, the controller 111 gradually reduces the opening of the electronic expansion valve 114, so that the flow rate of the refrigerant is reduced, and the economic efficiency of the system is prevented from being reduced due to the excessive refrigerant. When the cooling plate 112 has more gaseous refrigerant, the controller 111 gradually increases the opening of the electronic expansion valve 114, so as to increase the flow rate of the refrigerant and ensure the cooling effect.
In summary, the cooling system 110 adjusts the opening of the electronic expansion valve 114 according to the original temperature difference, so as to adjust the flow of the refrigerant, without considering the temperature of the heat dissipation cold plate 112, and without being affected by the working condition, the control is simple, the reaction is sensitive, the temperature target value does not need to be modified along with the working condition, and the product with changeable working condition can be well adapted.
In contrast, if the opening degree of the electronic expansion valve 114 is controlled by setting the temperature target value, it is considered that the temperature range corresponding to the "stable segment" is small and is related to the pressure, the temperature, and the like of the refrigerant, and when the refrigerant temperature and the pressure are high under a certain working condition, it is easy for the temperature range corresponding to the entire "stable segment" to be higher than the set temperature target value. At this time, the control algorithm will continuously increase the opening of the electronic expansion valve 114 until the opening of the electronic expansion valve 114 reaches the maximum value, and an excessive amount of unnecessary refrigerant is introduced, thereby reducing the economical efficiency.
Or when the temperature and pressure of the refrigerant under a certain working condition are low, the condition that the temperature range corresponding to the whole stable section is lower than the set temperature target value is easy to occur. At this point, the control algorithm will continuously decrease the opening of the electronic expansion valve 114, eventually causing the cooling system 110 to enter the "oscillation phase" causing severe temperature fluctuations.
In some embodiments, the number of heat sink cold plates 112 is one. Accordingly, the number of the temperature sensors 113 is two. One of the temperature sensors 113 is disposed at an inlet of the heat-dissipating cold plate 112, and the other temperature sensor 113 is disposed at an outlet of the heat-dissipating cold plate 112.
In other embodiments, the number of heat sink cold plates 112 is plural, and the plurality of heat sink cold plates 112 are connected in series. At this time, the number of temperature sensors 113 is still two. One of the temperature sensors 113 is disposed at an inlet of the first heat-dissipating cold plate 112, and the other temperature sensor 113 is disposed at an outlet of the last heat-dissipating cold plate 112.
In still other embodiments, the number of heat sink cold plates 112 is a plurality, and the plurality of heat sink cold plates 112 are connected in parallel. At this time, the inlet and outlet of each heat-dissipating cold plate 112 are provided with temperature sensors 113, and the inlet temperature T in Taking the inlet temperature of all heat dissipation cold plates 112Maximum value of degree, outlet temperature T out Taking the minimum value of all the heat sink cold plate 112 outlet temperatures.
Referring to fig. 1, the present embodiment further provides a frequency converter 100, which includes a heat generating unit 120 and the cooling system 110. Wherein the heat generating unit 120 is disposed on the heat dissipating cold plate 112.
When the frequency converter 100 works, heat generated by the heating unit 120 is mainly transferred to the heat-dissipating cold plate 112 in a heat conduction mode, and then transferred to a refrigerant in the heat-dissipating cold plate 112, so that cooling of the heating unit 120 is realized.
Illustratively, the heat generating unit 120 is a rectifying unit, an inverting unit, or the like in the frequency converter 100.
Referring to fig. 1, the present embodiment further provides a frequency converter unit, which includes a condenser 200, an evaporator 300, and the frequency converter 100.
Wherein, the outlet of the condenser 200 is communicated with the inlet of the heat-dissipating cold plate 112, and the inlet of the evaporator 300 is communicated with the outlet of the heat-dissipating cold plate 112 through the electronic expansion valve 114.
In use, the outlet pressure of the condenser 200 is relatively high and the inlet pressure of the evaporator 300 is low. Accordingly, the inlet pressure of the heat rejection cold plate 112 is higher than the outlet pressure.
Referring to fig. 3, the present embodiment further provides a control method of the cooling system 110, which is applied to the controller 111 of the cooling system 110, and includes the following steps:
s1, acquiring the inlet temperature and the outlet temperature of the heat dissipation cold plate 112.
Specifically, the inlet temperature measured by the temperature sensor 113 disposed at the inlet of the heat-dissipating cold plate 112 is collected and denoted as T in The outlet temperature measured by the temperature sensor 113 arranged at the outlet of the heat-dissipating cold plate 112 is collected and is denoted as T out 。
S2, calculating the difference between the outlet temperature and the inlet temperature according to the acquired inlet temperature and outlet temperature, and obtaining the original temperature difference.
Specifically, let the original temperature difference be Δt, Δt=t out -T in 。
And S3, adjusting the opening degree of the electronic expansion valve 114 according to the original temperature difference.
Specifically, as described above, when the flow rate of the refrigerant is sufficient and the refrigerant is in the "steady state", the inlet temperature T of the heat-dissipating cold plate 112 in Above the outlet temperature T out . At this time, the original temperature difference Δt is a negative value, and the opening of the electronic expansion valve 114 is gradually reduced, so that the flow rate of the refrigerant is reduced, and the economic efficiency of the system is prevented from being reduced due to the excessive refrigerant.
When the flow rate of the refrigerant is relatively insufficient and the refrigerant is in the "oscillation section", the outlet temperature of the heat-dissipating cold plate 112 gradually exceeds the inlet temperature. Accordingly, the original temperature difference Δt is continuously increased and gradually becomes positive. At this time, the opening degree of the electronic expansion valve 114 is gradually increased to increase the flow rate of the refrigerant, thereby ensuring the cooling effect.
Referring to fig. 4, further, in some embodiments, step S3 includes the steps of:
s31, obtaining control deviation according to the temperature interval where the original temperature difference is located.
And S32, adjusting the opening degree of the electronic expansion valve 114 according to the control deviation.
The control target of the original temperature difference is set to be a section instead of a fixed value, so that the robustness of the controller 111 is high, frequent actions of the electronic expansion valve 114 are not caused, and the service life of the electronic expansion valve 114 is prolonged.
Referring to fig. 5, in some embodiments, step S31 includes the following steps:
s311, if the original temperature difference is smaller than or equal to the first preset value, calculating a difference value between the original temperature difference and the first preset value, and obtaining a control deviation.
S312, if the original temperature difference is larger than the first preset value and smaller than the second preset value, the control deviation is equal to zero.
S313, if the original temperature difference is greater than or equal to the second preset value, calculating the difference between the original temperature difference and the second preset value to obtain the control deviation.
Wherein the first preset value is smaller than the second preset value.
Specifically, the control deviation is recorded as Δt 0 The first preset value is T 1 The second preset value is T 2 The original temperature difference DeltaT and the control deviation DeltaT 0 The conversion scheme of (2) is as follows:
after deviation treatment, PID control, rod control, fuzzy control and the like suitable for closed-loop control can be used.
Illustratively T 1 At-2 ℃, T 2 Is +2℃.
Referring to fig. 6, in some embodiments, step S32 uses bar control, which is as follows:
s321, if the control deviation is smaller than zero, the opening degree of the electronic expansion valve 114 is reduced.
S322, if the control deviation is greater than zero, the opening degree of the electronic expansion valve 114 is increased.
When the opening of the electronic expansion valve 114 is adjusted, the adjustment amount is a first step, denoted as Δp 1 。
Illustratively, ΔP 1 1%.
Referring to fig. 7, in other embodiments, step S32 uses PID control. Wherein the deviation DeltaT is controlled 0 The opening P of the electronic expansion valve 114 is the output of the PID control module 30, which is the input of the PID control module 30.
Referring to fig. 8 and fig. 9 together, in some embodiments, step S2' is further included before step S3, and the specific steps are as follows:
s21', calculating the highest temperature, wherein the highest temperature is equal to the larger one of the inlet temperature and the outlet temperature.
Specifically, the highest temperature is recorded as T max T is then max =max(T in ，T out )。
S22', judging whether the highest temperature is larger than a third preset value.
Specifically, the third preset value is a high temperature threshold, denoted as T 3 。
Illustratively T 3 Is 50 ℃.
If the maximum temperature is greater than the third preset value, S23', the opening degree of the electronic expansion valve 114 is increased.
Specifically, if T max ＞T 3 Indicating that the temperature of the heat-dissipating cold plate 112 has exceeded the high temperature threshold, there is an over-temperature risk, and emergency control needs to be performed: in a second step length delta P 2 Increasing the opening of the electronic expansion valve 114 to rapidly increase the refrigerant flow, and the second step ΔP 2 Greater than a first step size DeltaP 1 。
Illustratively, ΔP 2 5%.
If the highest temperature is not greater than the third preset value, step S24' is performed to adjust the opening of the electronic expansion valve 114 according to the original temperature difference.
Specifically, if T max ≤T 3 The heat dissipation cold plate 112 is illustrated to have no risk of overheat, and conventional control is performed to control the original temperature difference Δt to be within the interval [ T ] 1 ，T 2 ]And (3) inner part.
It should be noted that the sequence of the step S2 and the step S2' is not limited.
In a word, the control method is not influenced by working conditions, is simple to control, is sensitive to respond, does not need to modify a temperature target value along with the working conditions, and can be well adapted to products with changeable working conditions.
In correspondence to the above-mentioned method embodiment, referring to fig. 9, a block diagram of a control device of a cooling system 110 according to the present embodiment is provided, where the provided control device is applied to a controller 111 of the cooling system 110. As shown in fig. 1, the cooling system 110 further includes a heat-dissipating cold plate 112, a temperature sensor 113, and an electronic expansion valve 114, wherein the temperature sensor 113 is disposed at an inlet and an outlet of the heat-dissipating cold plate 112, the temperature sensor 113 is electrically connected to the controller 111, the electronic expansion valve 114 is disposed at an outlet of the heat-dissipating cold plate 112, and the electronic expansion valve 114 is electrically connected to the controller 111.
Referring to fig. 10, the control device includes:
the information acquisition module 10 is used for acquiring the inlet temperature and the outlet temperature of the heat dissipation cold plate 112;
the calculating module 20 calculates a difference value between the outlet temperature and the inlet temperature according to the acquired inlet temperature and outlet temperature, and obtains an original temperature difference;
the control module 30 is used for adjusting the opening degree of the electronic expansion valve 114 according to the original temperature difference.
Any particular values in all examples shown and described herein are to be construed as merely illustrative and not a limitation, and thus other examples of exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
The above examples merely represent a few embodiments of the present invention, which are described in more detail and are not to be construed as limiting the scope of the present invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.
Claims (9)
1. A control method of a cooling system, characterized in that the cooling system comprises a heat-dissipating cold plate, a temperature sensor and an electronic expansion valve, wherein the heat-dissipating cold plate is provided with an inlet and an outlet, and the electronic expansion valve is arranged at the outlet of the heat-dissipating cold plate;
the control method comprises the following steps:
acquiring the inlet temperature and the outlet temperature of the heat dissipation cold plate;
calculating the difference between the outlet temperature and the inlet temperature according to the acquired inlet temperature and outlet temperature to obtain an original temperature difference;
and adjusting the opening of the electronic expansion valve according to the original temperature difference.
2. The control method according to claim 1, wherein the step of adjusting the opening degree of the electronic expansion valve according to the original temperature difference includes:
obtaining control deviation according to a temperature interval where the original temperature difference is located;
and adjusting the opening degree of the electronic expansion valve according to the control deviation.
3. The control method according to claim 2, wherein the step of obtaining the control deviation according to the temperature interval in which the original temperature difference is located includes:
if the original temperature difference is smaller than or equal to a first preset value, calculating a difference value between the original temperature difference and the first preset value to obtain the control deviation;
if the original temperature difference is larger than the first preset value and smaller than the second preset value, the control deviation is equal to zero;
if the original temperature difference is larger than or equal to the second preset value, calculating a difference value between the original temperature difference and the second preset value to obtain the control deviation;
wherein the first preset value is smaller than the second preset value.
4. A control method according to claim 3, wherein the step of adjusting the opening degree of the electronic expansion valve according to the control deviation includes:
if the control deviation is smaller than zero, reducing the opening of the electronic expansion valve;
and if the control deviation is larger than zero, increasing the opening degree of the electronic expansion valve.
5. The control method according to any one of claims 1 to 4, characterized by further comprising, before the step of adjusting the opening degree of the electronic expansion valve according to the original temperature difference:
calculating a maximum temperature, the maximum temperature being equal to the greater of the inlet temperature and the outlet temperature;
judging whether the highest temperature is larger than a third preset value or not;
if the highest temperature is greater than the third preset value, increasing the opening of the electronic expansion valve;
and if the highest temperature is not greater than the third preset value, adjusting the opening of the electronic expansion valve according to the original temperature difference.
6. A control device of a cooling system, characterized in that the cooling system comprises a heat-dissipating cold plate, a temperature sensor and an electronic expansion valve, wherein the heat-dissipating cold plate is provided with an inlet and an outlet, and the electronic expansion valve is arranged at the outlet of the heat-dissipating cold plate;
the control device includes:
the information acquisition module is used for acquiring the inlet temperature and the outlet temperature of the heat dissipation cold plate;
the calculation module is used for calculating the difference value between the outlet temperature and the inlet temperature according to the acquired inlet temperature and outlet temperature to obtain an original temperature difference;
and the control module is used for adjusting the opening of the electronic expansion valve according to the original temperature difference.
7. A cooling system, comprising:
a controller for executing the control method according to any one of claims 1 to 5;
a heat-dissipating cold plate having an inlet and an outlet;
a temperature sensor; and
and the electronic expansion valve is arranged at the outlet of the heat dissipation cold plate.
8. A frequency converter comprising a heat generating unit and the cooling system of claim 7, the heat generating unit disposed on the heat dissipating cold plate.
9. A frequency converter unit comprising a condenser, an evaporator and the frequency converter of claim 8;
the outlet of the condenser is communicated with the inlet of the heat dissipation cold plate, and the inlet of the evaporator is communicated with the outlet of the heat dissipation cold plate through the electronic expansion valve.
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| CN202410009062.2A CN117529065A (en) | 2024-01-04 | 2024-01-04 | Control method and device, cooling system, frequency converter and frequency converter unit |
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