CN112177961B - Fan frequency control method and device, air curtain machine and display cabinet - Google Patents
Fan frequency control method and device, air curtain machine and display cabinet Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 42
- 238000010257 thawing Methods 0.000 claims abstract description 38
- 238000005057 refrigeration Methods 0.000 claims abstract description 21
- 238000001514 detection method Methods 0.000 claims description 50
- 238000001816 cooling Methods 0.000 claims description 16
- 238000004590 computer program Methods 0.000 claims description 3
- 230000007613 environmental effect Effects 0.000 abstract description 2
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/004—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying driving speed
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47F—SPECIAL FURNITURE, FITTINGS, OR ACCESSORIES FOR SHOPS, STOREHOUSES, BARS, RESTAURANTS OR THE LIKE; PAYING COUNTERS
- A47F3/00—Show cases or show cabinets
- A47F3/04—Show cases or show cabinets air-conditioned, refrigerated
- A47F3/0439—Cases or cabinets of the open type
- A47F3/0443—Cases or cabinets of the open type with forced air circulation
- A47F3/0447—Cases or cabinets of the open type with forced air circulation with air curtains
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47F—SPECIAL FURNITURE, FITTINGS, OR ACCESSORIES FOR SHOPS, STOREHOUSES, BARS, RESTAURANTS OR THE LIKE; PAYING COUNTERS
- A47F3/00—Show cases or show cabinets
- A47F3/04—Show cases or show cabinets air-conditioned, refrigerated
- A47F3/0478—Control or safety arrangements
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- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Defrosting Systems (AREA)
- Cold Air Circulating Systems And Constructional Details In Refrigerators (AREA)
- Devices That Are Associated With Refrigeration Equipment (AREA)
Abstract
The invention discloses a fan frequency control method and device, an air curtain machine and a display cabinet. Wherein, the method comprises the following steps: determining an operation mode of the air curtain machine; wherein the operating mode comprises at least one of: a refrigeration mode, a defrost mode; acquiring the current air outlet speed of the air curtain machine; and adjusting the frequency of the fan according to the operation mode and the current air outlet speed. The invention can ensure that the air outlet speed of the air curtain machine is constant and cannot be changed due to the influence of frosting or defrosting, thereby ensuring that the environmental temperature of the articles in the air curtain is constant and ensuring the quality of the articles.
Description
Technical Field
The invention relates to the technical field of temperature control equipment, in particular to a fan frequency control method and device, an air curtain machine and a display cabinet.
Background
The open showcase mainly utilizes an air curtain jetted from an air outlet of an air curtain machine to separate a low-temperature environment in the showcase from a high-temperature environment outside the showcase so as to reduce the invasion of heat. The performance of the air curtain directly affects the temperature balance within the cabinet and the quality of the stored goods.
At present, most of the existing show cases adopt a fixed-frequency fan to maintain an air curtain. Because the evaporimeter frosts gradually and leads to fan static pressure grow, because the frequency of fan is certain, fan static pressure increase, even if consequently with the air curtain that the optimal air-out wind speed formed when initial condition, the wind speed of air curtain also can reduce gradually, can directly destroy the air curtain on the whole even when serious, lead to a large amount of heats to pour into in the show case from the external environment for the excessive cold phenomenon of air curtain machine is serious, and energy resource consumption is big.
The problem that the static pressure of a fan is increased and the wind speed is reduced due to gradual frosting of an evaporator in the prior art is solved.
Disclosure of Invention
The embodiment of the invention provides a fan frequency control method and device, an air curtain machine and a display cabinet, and aims to solve the problem that in the prior art, the static pressure of a fan is increased due to gradual frosting of an evaporator, and further the wind speed is reduced.
In order to solve the technical problem, the invention provides a fan frequency control method, wherein the method comprises the following steps:
determining an operation mode of the air curtain machine; wherein the operating mode comprises at least one of: a refrigeration mode, a defrost mode;
acquiring the current air outlet speed of the air curtain machine;
and adjusting the frequency of the fan according to the operation mode and the current air outlet speed.
Further, obtain the current air-out wind speed of air curtain machine, include:
acquiring the air outlet speeds of a plurality of detection points at preset time intervals; the detection points are all positioned on the air outlet side of the evaporator of the air curtain machine;
and calculating the average air outlet speed according to the air outlet speeds of the plurality of detection points to serve as the current air outlet speed.
Further, when the average outlet air speed is calculated according to the outlet air speeds of the plurality of detection points, the formula according to which the average outlet air speed is calculated is as follows:
wherein S isAt presentIs the current wind speed S1Is the wind speed at the first detection point, S2Is the wind speed at the second detection point, SnThe wind speed at the nth detection point is shown, n is the number of the detection points, a is the number of data groups acquired within the preset time length, and i is the serial number of the data groups acquired within the preset time length.
Further, according to operation mode and current air-out wind speed regulation fan frequency, include:
if the operation mode of the air curtain machine is a refrigeration mode, controlling the frequency of the fan to rise according to the current air outlet speed;
and if the operation mode of the air curtain machine is a defrosting mode, controlling the frequency of the fan to be reduced according to the current air outlet speed.
Further, according to the rising of current air-out wind speed control fan frequency, include:
determining a first target fan frequency according to the difference value between the target air outlet speed and the current air outlet speed;
and controlling the fan to operate according to the first target fan frequency.
Further, when the first target fan frequency is determined according to the difference between the target air-out wind speed and the current air-out wind speed, the formula according to which the first target fan frequency is determined is as follows:
f(n1)＝f(0)+K*(Starget-SAt present)；
Wherein f (n1) is a first target fan frequency, K is an adjustment coefficient, STargetIs the target air outlet speed, SAt presentThe current wind outlet speed.
Further, after controlling the frequency of the fan to increase according to the current outlet air speed, the method further comprises:
judging whether the current fan frequency is greater than a frequency upper limit value or not;
if yes, triggering to enter a defrosting mode;
if not, triggering to adjust the fan frequency according to the operation mode and the current air outlet speed, and triggering to enter the defrosting mode after the current fan frequency is greater than the upper limit value of the frequency.
Further, according to the reduction of current air-out wind speed control fan frequency, include:
determining a second target fan frequency according to the difference value between the current air outlet speed and the target air outlet speed;
and controlling the fan to operate according to the second target fan frequency.
Further, when the second target fan frequency is determined according to the difference between the current air-out wind speed and the target air-out wind speed, the formula according to which the frequency of the second target fan is determined is as follows:
f(n2)＝f(0)-K*(Sat present-STarget)；
Wherein f (n2) is the second target fan frequency, K is the adjustment coefficient, STargetIs the target air outlet speed, SAt presentThe current wind outlet speed.
Further, after controlling the fan frequency to decrease according to the current outlet air speed, the method further comprises:
judging whether the current fan frequency is smaller than a lower frequency limit value or not;
if yes, triggering to enter a cooling mode;
if not, triggering to adjust the fan frequency according to the operation mode and the current air outlet speed until the current fan frequency is smaller than the lower frequency limit value, and triggering to enter a refrigeration mode.
The invention also provides a fan frequency control device, which is used for realizing the fan frequency control method and is characterized by comprising the following steps:
the determining module is used for determining the operation mode of the air curtain machine; the operating mode includes at least one of: a refrigeration mode, a defrost mode;
the acquiring module is used for acquiring the current air outlet speed of the air curtain machine;
and the adjusting module is used for adjusting the frequency of the fan according to the operation mode and the current air outlet speed.
The invention also provides an air curtain machine, which comprises an evaporator, a fan and the fan frequency control device.
The invention also provides a display cabinet comprising the air curtain machine.
The invention also provides a computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the above-mentioned method.
By applying the technical scheme of the invention, the operation mode of the air curtain machine is judged to be a refrigeration mode or a defrosting mode, the current air outlet speed of the air curtain machine is obtained, and then the frequency of the fan is adjusted according to the operation mode and the current air outlet speed. In the refrigeration mode or the defrosting mode, the air outlet speed of the air curtain machine can be ensured to be constant by adjusting the frequency of the fan, and the air curtain machine cannot be influenced by frosting or defrosting to change, so that the temperature of the environment where articles in the air curtain are located is ensured to be constant, and the quality of the articles is ensured.
Drawings
FIG. 1 is a block diagram of an air curtain according to an embodiment of the present invention;
FIG. 2 is a flow chart of a method of controlling fan frequency according to an embodiment of the present invention;
FIG. 3 is a flow chart of a method of controlling a fan frequency according to another embodiment of the present invention;
FIG. 4 is a schematic diagram of mode switching according to an embodiment of the present invention;
FIG. 5 is a block diagram of a fan frequency control apparatus according to an embodiment of the present invention;
FIG. 6 is a schematic view of a wind speed sensor arrangement according to an embodiment of the present invention;
fig. 7 is a structural diagram of a fan frequency control apparatus according to another embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a plurality" typically includes at least two.
It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
It should be understood that although the terms first, second, etc. may be used to describe the detection points in embodiments of the present invention, these detection points should not be limited to these terms. These terms are only used to distinguish between different detection points. For example, the first detection point may also be referred to as the second detection point, and similarly, the second detection point may also be referred to as the first detection point, without departing from the scope of embodiments of the present invention.
The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.
It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in the article or device in which the element is included.
Alternative embodiments of the present invention are described in detail below with reference to the accompanying drawings.
Example 1
This embodiment provides a method for controlling a fan frequency, which is applied to an air curtain machine, and fig. 1 is a structural diagram of the air curtain machine according to an embodiment of the present invention, as shown in fig. 1, the air curtain machine includes: the evaporator 1, the fan 2, the throttling device 3, the liquid supply electromagnetic valve 4, the liquid heat exchange medium flows to the evaporator 1 through the liquid supply electromagnetic valve 4 and the throttling device 3, the liquid heat exchange medium is evaporated and absorbs heat in the evaporator 1, so that the temperature of air around the evaporator 1 is reduced, and the fan 2 blows out cold air generated around the evaporator 1 to form an air curtain.
Fig. 2 is a flowchart of a fan frequency control method according to an embodiment of the present invention, and as shown in fig. 2, the method includes:
s201, determining an operation mode of an air curtain machine; wherein the operation mode comprises at least one of: a cooling mode and a defrosting mode.
In the cooling mode, frost is gradually accumulated on the surface of the evaporator, which leads to increase of static pressure of the fan, so that under the condition that the frequency of the fan is not changed, the wind speed is gradually reduced along with increase of frost accumulation, and under the defrosting mode, the frost on the surface of the evaporator is gradually melted, which leads to reduction of static pressure of the fan, under the condition that the frequency of the fan is not changed, the wind speed is gradually increased along with reduction of frost accumulation, therefore, in order to accurately adjust the frequency of the fan to ensure constant wind speed, before adjusting the frequency of the fan, the operation mode of the air curtain machine needs to be determined, so that the frequency of the fan can be adjusted by adopting a proper adjustment strategy.
S202, acquiring the current air outlet speed of the air curtain machine.
In order to accurately adjust the fan frequency according to the current operating condition, after the operating mode of the air curtain machine is determined, the current outlet air speed also needs to be acquired, so that the direction and the amplitude of the adjustment frequency can be determined according to the current outlet air speed.
And S203, adjusting the fan frequency according to the operation mode and the current air outlet speed.
After the operation mode and the current air outlet speed of the air curtain machine are determined through the steps, the frequency of the fan can be adjusted according to the operation mode and the current air outlet speed so as to ensure constant air speed.
According to the fan frequency control method, firstly, whether the operation mode of the air curtain machine is the refrigeration mode or the defrosting mode is judged, the current air outlet speed of the air curtain machine is obtained, and then the fan frequency is adjusted according to the operation mode and the current air outlet speed. This embodiment is under refrigeration mode or defrosting mode, through adjusting fan frequency, can guarantee that the air-out wind speed of air curtain machine is invariable, can not receive the influence of frosting or defrosting and change, and then guarantees the environmental temperature invariant that article in the air curtain were located, guarantees the quality of article.
Example 2
In this embodiment, another fan frequency control method is provided, in order to accurately obtain the current air outlet speed, the step S202 specifically includes:
acquiring the air outlet speeds of a plurality of detection points at preset time intervals; the detection points are all positioned on the air outlet side of an evaporator of the air curtain machine; acquiring the air outlet speed of the plurality of detection points can be realized by arranging a plurality of air speed sensors on the air outlet side of an evaporator of the air curtain machine, for example, the air outlet speed is acquired in real time through the plurality of air speed sensors, and all air speed data acquired by the plurality of air speed sensors within the last 1s time is acquired every 1 s; and calculating the average air outlet speed according to the air outlet speeds of the plurality of detection points to serve as the current air outlet speed.
Specifically, when the average outlet air speed is calculated according to the outlet air speeds of the plurality of detection points, the formula according to which:
wherein S isAt presentIs the current wind speed S1Is the wind speed at the first detection point, S2Is the wind speed at the second detection point, SnThe wind speed at the nth detection point is shown, n is the number of the detection points, a is the number of the data groups acquired within the preset time length, and i is the serial number of the acquired data groups.
In order to match the frequency adjustment strategy with the operation mode of the air curtain machine, the step S203 specifically includes: if the operation mode of the air curtain machine is a refrigeration mode, controlling the frequency of the fan to rise according to the current air outlet speed; and if the operation mode of the air curtain machine is the defrosting mode, controlling the frequency of the fan to be reduced according to the current air outlet speed.
In order to ensure that the amplitude of frequency rise is matched with the current air outlet speed, the frequency rise of the fan is controlled according to the current air outlet speed, and the method comprises the following steps: determining a first target fan frequency according to the difference value between the target air outlet speed and the current air outlet speed; and controlling the fan to operate according to the first target fan frequency. When the first target fan frequency is determined according to the difference value between the target air-out wind speed and the current air-out wind speed, the formula according to which the frequency is determined is as follows:
f(n1)＝f(0)+K*(Starget-SAt present)；
Wherein f (n1) is a first target fan frequency, f (0) is a current fan frequency, the units of f (n1) and f (0) are Hz, K is an adjusting coefficient, S isTargetIs the target air outlet speed, SAt presentIs the current wind speed STargetAnd SAt presentThe units of (A) are m/s, and the calculation according to the formula only carries out numerical operation and does not carry out the units. For example, if the current fan frequency is 50Hz, the current outlet wind speed is 8m/s, the first target outlet wind speed is 10m/s, and the coefficient K is 3, then the calculation is performed according to the above formula: 50+3 (10-8) ═ 56, the fan frequency should be adjusted to 56 Hz. The above is only an example, in specific implementation, the target air outlet speed may be set according to actual needs, the current air outlet speed is obtained by detection, the current fan frequency is also obtained by detection, and for the coefficient K, since the frequency of the variable frequency fan is proportional to the rotation speed, which is proportional to the air volume, the rotation speeds corresponding to different frequencies of the fan under the same static pressure can be measured based on experiments, so as to determine the value K. In the present invention, the specific values of the above parameters are not limited, and in the specific implementation, those skilled in the art can set the values according to the needs.
In the cooling mode, if the frequency of the fan rises to the upper limit of the frequency, the wind speed cannot be maintained constant by the mode of raising the frequency, and therefore, the air curtain machine needs to be controlled to defrost, and after the frequency of the fan is controlled to rise according to the current wind outlet speed, the method further comprises the following steps: judging whether the current fan frequency is greater than a frequency upper limit value or not; if yes, triggering to enter a defrosting mode; if not, triggering to adjust the fan frequency according to the operation mode and the current air outlet speed, and triggering to enter the defrosting mode after the current fan frequency is greater than the upper limit value of the frequency. According to the scheme, when the frequency of the fan rises to the upper limit value of the frequency and cannot rise any more, defrosting is carried out in time, and the wind speed is kept constant continuously.
Similarly, in order to ensure that the amplitude of the frequency reduction is matched with the current wind outlet speed, the frequency reduction of the fan is controlled according to the current wind outlet speed, and the method comprises the following steps: determining a second target fan frequency according to the difference value between the current air outlet speed and the target air outlet speed; and controlling the fan to operate according to the second target fan frequency. When the second target fan frequency is determined according to the difference value between the current air outlet speed and the target air outlet speed, the formula is as follows:
f(n2)＝f(0)-K*(Sat present-STarget)；
Wherein f (n2) is the second target fan frequency, f (0) is the current fan frequency, the units of f (n2) and f (0) are both Hz, K is the regulating coefficient, S isTargetIs the target air outlet speed, SAt presentIs the current wind speed STargetAnd SAt presentThe units of (A) are m/s, and the calculation according to the formula only carries out numerical operation and does not carry out the units.
In the defrosting mode, if the frequency of the fan is reduced to the lower frequency limit value, the wind speed is not required to be maintained to be constant by reducing the frequency, so that the wind curtain machine can be controlled to normally refrigerate, and after the frequency of the fan is controlled to be reduced according to the current wind outlet speed, the method further comprises the following steps: judging whether the current fan frequency is smaller than a lower frequency limit value or not; if yes, triggering to enter a cooling mode; if not, triggering to adjust the fan frequency according to the operation mode and the current air outlet speed until the current fan frequency is smaller than the lower frequency limit value, and triggering to enter a refrigeration mode. The lower limit value of the frequency is the fan frequency which reaches the target air outlet speed when the evaporator is not frosted. Through the scheme, when the frequency of the fan is reduced to the lower limit value of the frequency and does not need to be reduced, the fan enters a normal refrigeration mode in time, and the wind speed is kept constant.
Example 3
The present embodiment provides another fan frequency control method, which is applied to an air curtain machine, as shown in fig. 1 mentioned above, the air curtain machine includes: a liquid supply electromagnetic valve 4, a throttling device 3, an evaporator 1 and a fan 2. The fan used in the invention is a variable frequency fan, n wind speed sensors are arranged on the air outlet side of the evaporator of the conventional refrigerating system of the air curtain machine according to the actual design length of the evaporator 1 and are connected with the main board by using signal lines, and the wind speed detection value is transmitted in real time. Fig. 3 is a flowchart of a fan frequency control method according to another embodiment of the present invention, as shown in fig. 3, the method includes.
And S1, according to different designed evaporators, confirming the parameters of the actual evaporator through matching, and determining a lower frequency limit value f (1) and an upper frequency limit value f (h).
Determining that the target air outlet speed S is achieved in the frostless stateTargetThe time fan frequency is used as a frequency lower limit value f (1), and the target air outlet speed S is reached under the condition that the frosting is the most seriousTargetThe time fan frequency is used as the frequency upper limit value f (h). And setting a lower limit value f (1) and an upper limit value f (h) of the operating frequency of the fan on the mainboard according to the matching result. Wherein, the frosting degree can be detected visually or by other modes such as image acquisition and the like.
And S2, controlling the liquid supply electromagnetic valve to be opened, operating the refrigeration mode, and controlling the fan to operate at the lower frequency limit value f (1).
S3, detecting the wind speeds of the points S1, S2, … and Sn in real time by the wind speed sensor, acquiring the wind speed of each detection point every 1S of the main board, and calculating the current wind outlet speed SAt present。
According to the formula:
calculating the average value of the wind speed within the preset time t as the current wind outlet speed SAt present. Wherein S is1Is the wind speed at the first detection point, S2Is the wind speed at the second detection point, SnThe wind speed at the nth detection point is shown, n is the number of the detection points, a is the number of data groups acquired within the preset time length, and i is the serial number of the data groups acquired within the preset time length.
And S4, calculating a target frequency f (n) and adjusting the fan frequency to the target frequency f (n).
According to the formula f (n) ═ f (0) + K (S)Target-SAt present) And calculating a target frequency f (n) and adjusting the fan frequency to the target frequency f (n). Wherein f (0) is the current fan frequency, the units of f (n) and f (0) are Hz, STargetIs the target air outlet speed, SAt presentIs the current wind speed STargetAnd SAt presentThe unit of the frequency conversion fan is m/s, K is an adjusting coefficient, is a constant and has no unit, and the frequency of the frequency conversion fan is in direct proportion to the rotating speed which is in turn in direct proportion to the windThe K value can be determined according to the rotating speeds of the fan corresponding to different frequencies under the same static pressure.
S5, the mainboard synchronously compares the target frequency f (n) with the highest running frequency f (h), judges whether f (n) > f (h) is true, if not, returns to the step S3; if yes, go to step S6;
and S6, closing the liquid supply electromagnetic valve, entering a defrosting mode, and controlling the fan to operate at the upper frequency limit value f (h).
S7, detecting the wind speeds of the points S1, S2, … and Sn in real time by the wind speed sensor, acquiring the wind speed of each detection point every 1S of the main board, and calculating the current wind outlet speed SAt present。
The specific calculation formula is the same as step S3, and is not described herein again.
And S8, calculating a target frequency f (n) and adjusting the fan frequency to the target frequency f (n).
The specific calculation formula is the same as step S4, and is not described herein again. The difference is only that in this case STarget-SAt presentIs a negative number.
S9, the mainboard synchronously compares the target frequency f (n) with the frequency lower limit value f (1), judges whether f (n) < f (1) is true, if not, returns to the step S7; if yes, go to step S2.
Fig. 4 is a schematic diagram of mode switching according to an embodiment of the present invention, as shown in fig. 4, an arrow direction represents a mode switching direction, when the cooling mode is switched to the defrosting mode, the critical value of the fan frequency is an upper frequency limit value f (h), when the fan frequency is greater than the upper frequency limit value f (h), the cooling mode is switched to the defrosting mode, when the defrosting mode is switched to the cooling mode, the critical value of the fan frequency is a lower frequency limit value f (1), and when the fan frequency is less than the lower frequency limit value f (1), the defrosting mode is switched to the cooling mode.
By using the variable frequency fan, the frequency is adjusted according to the current air outlet speed, so that the air speed of the air curtain is kept constant, and meanwhile, the intelligent defrosting control is performed by using the fan to maintain the difference of the required frequency of the air speed under different static pressures. Therefore, the cold energy overflow can be reduced, and the display cabinet is suitable for various humidity environments.
Example 4
This embodiment provides a fan frequency control device, which is used to implement the fan frequency control method in the foregoing embodiment, and fig. 5 is a structural diagram of the fan frequency control device according to the embodiment of the present invention, as shown in fig. 5, the device includes:
the determining module 10 is used for determining the operation mode of the air curtain machine; the operation mode includes at least one of: a cooling mode and a defrosting mode. In the cooling mode, frost is gradually accumulated on the surface of the evaporator, which leads to increase of static pressure of the fan, so that under the condition that the frequency of the fan is not changed, the wind speed is gradually reduced along with increase of frost accumulation, and under the defrosting mode, the frost on the surface of the evaporator is gradually melted, which leads to reduction of static pressure of the fan, under the condition that the frequency of the fan is not changed, the wind speed is gradually increased along with reduction of frost accumulation, in order to accurately adjust the frequency of the fan to ensure constant wind speed, before adjusting the frequency of the fan, the operation mode of the air curtain machine needs to be determined by the determining module 10, so that the frequency of the fan can be adjusted by adopting a proper adjusting strategy.
And the obtaining module 20 is configured to obtain a current air outlet speed of the air curtain machine. In order to accurately adjust the fan frequency according to the current operating condition, after the determining module 10 determines the operating mode of the air curtain machine, the obtaining module 20 needs to obtain the current outlet air speed, so as to determine the direction and amplitude of the adjustment frequency according to the current outlet air speed.
And the adjusting module 30 is used for adjusting the fan frequency according to the operation mode and the current air outlet speed.
After the operation mode and the current air outlet speed of the air curtain machine are determined through the steps, the fan frequency can be adjusted through the adjusting module 30 according to the operation mode and the current air outlet speed, so that the constant air speed is ensured.
The fan frequency control device of the embodiment determines whether the operation mode of the air curtain machine is a refrigeration mode or a defrosting mode through the determination module 10; acquiring the current air outlet speed of the air curtain machine through an acquisition module 20; the fan frequency is adjusted through the adjusting module 30 according to the operation mode and the current air outlet speed, the air outlet speed of the air curtain machine can be guaranteed to be constant in the refrigeration mode or in the defrosting mode through adjusting the fan frequency, the air outlet speed cannot be influenced by frosting or defrosting to change, the environment temperature where articles in the air curtain are located is guaranteed to be constant, and the quality of the articles is guaranteed.
In order to accurately obtain the current air outlet speed, the obtaining module 20 is specifically configured to: acquiring the air outlet speeds of a plurality of detection points at preset time intervals; the detection points are all positioned on the air outlet side of an evaporator of the air curtain machine; the obtaining module 20 includes a plurality of wind speed sensors, fig. 6 is a schematic diagram of the setting positions of the wind speed sensors according to the embodiment of the present invention, as shown in fig. 6, the plurality of wind speed sensors 20-1 and 20-2 … … 20-n are arranged on the air outlet side of the evaporator of the air curtain machine, the wind speed of the outlet air is obtained in real time by the plurality of wind speed sensors, and all the wind speed data obtained by the plurality of wind speed sensors within 1s is obtained every interval of 1 s; the adjusting module 30 calculates an average outlet air speed according to the outlet air speeds at the plurality of detection points, and the average outlet air speed is used as the current outlet air speed. When the adjusting module 30 calculates the average outlet air speed according to the outlet air speeds at the plurality of detecting points, the formula according to which:
wherein S isAt presentFor the current air outlet speed, t is the preset duration, S1Is the wind speed at the first detection point, S2Is the wind speed at the second detection point, SnThe wind speed at the nth detection point is shown, n is the number of the detection points, a is the number of data groups acquired within the preset time length, and i is the serial number of the data groups acquired within the preset time length.
Fig. 7 is a block diagram of a fan frequency control apparatus according to another embodiment of the present invention, and in order to match a frequency adjustment strategy with an operation mode of an air curtain machine, as shown in fig. 7, the adjusting module 30 includes: the first adjusting unit 301 is configured to control the frequency of the fan to increase according to the current outlet air speed when the operation mode of the air curtain machine is the cooling mode; the second adjusting unit 302 is configured to control the fan frequency to decrease according to the current outlet air speed when the operation mode of the air curtain machine is the defrosting mode.
In order to ensure that the frequency rise amplitude is matched with the current outlet air speed, the first adjusting unit 301 is specifically configured to: determining a first target fan frequency according to the difference value between the target air outlet speed and the current air outlet speed; and controlling the fan to operate according to the first target fan frequency. When the first adjusting unit 301 determines the first target fan frequency according to the difference between the target air-out wind speed and the current air-out wind speed, the formula according to which is:
f(n1)＝f(0)+K*(Starget-SAt present)；
Wherein f (n1) is a first target fan frequency, f (0) is a current fan frequency, the units of f (n1) and f (0) are Hz, K is an adjusting coefficient, S isTargetIs the target air outlet speed, SAt presentIs the current wind speed STargetAnd SAt presentThe units of (A) are m/s, and the calculation according to the formula only carries out numerical operation and does not carry out the units.
In the cooling mode, if the frequency of the fan rises to the upper limit of the frequency, the wind speed cannot be maintained constant by the way of raising the frequency, and therefore, the air curtain machine needs to be controlled to defrost, and therefore, the adjusting module 30 further includes a first determining unit 303, configured to determine whether the current fan frequency is greater than the upper limit of the frequency after controlling the fan frequency to rise according to the current wind outlet speed; the system further comprises a first switching unit 304, which is used for triggering to enter a defrosting mode when the current fan frequency is greater than the upper frequency limit value; when the current fan frequency is less than or equal to the upper frequency limit value, the first adjusting unit 301 continues to control the fan frequency to increase according to the current outlet air speed until the current fan frequency is greater than the upper frequency limit value, and the first switching unit 304 triggers entering the defrosting mode. According to the scheme, when the frequency of the fan rises to the upper limit value of the frequency and cannot rise any more, defrosting is carried out in time, and the wind speed is kept constant continuously.
Similarly, in order to ensure that the amplitude of the frequency reduction matches the current wind outlet speed, the second adjusting unit 302 is specifically configured to: determining a second target fan frequency according to the difference value between the current air outlet speed and the target air outlet speed; and controlling the fan to operate according to the second target fan frequency. When the second adjusting unit 302 determines the second target fan frequency according to the difference between the current outlet air speed and the target outlet air speed, the formula according to which is:
f(n2)＝f(0)-K*(Sat present-STarget)；
Wherein f (n2) is the second target fan frequency, f (0) is the current fan frequency, the units of f (n2) and f (0) are both Hz, K is the regulating coefficient, S isTargetIs the target air outlet speed, SAt presentIs the current wind speed STargetAnd SAt presentThe units of (A) are m/s, and the calculation according to the formula only carries out numerical operation and does not carry out the units.
In the defrosting mode, if the frequency of the fan is reduced to the lower frequency limit, the air curtain machine may be controlled to perform normal refrigeration without maintaining the constant air speed by reducing the frequency, and therefore, the adjusting module 30 further includes a second determining unit 305, configured to determine whether the current fan frequency is less than the lower frequency limit after controlling the fan frequency to be reduced according to the current outlet air speed; the second switching unit 306 is configured to trigger to enter a cooling mode when the current fan frequency is smaller than the lower frequency limit value; when the current fan frequency is greater than or equal to the lower frequency limit value, the second adjusting unit 302 continues to control the fan frequency to decrease according to the current outlet air speed until the current fan frequency is less than the lower frequency limit value, and the second switching unit 306 triggers to enter the cooling mode. The lower limit value of the frequency is the fan frequency which reaches the target air outlet speed when the evaporator is not frosted. Through the scheme, when the frequency of the fan is reduced to the lower limit value of the frequency and does not need to be reduced, the fan enters a normal refrigeration mode in time, and the wind speed is kept constant.
Example 5
The present embodiment provides an air curtain machine, which includes an evaporator and a fan, and further includes a fan frequency control device in the foregoing embodiments, for maintaining a constant air speed of the air curtain.
Example 6
This embodiment provides a showcase, which includes the air curtain machine in embodiment 5, and is configured to maintain a constant outlet air speed of the air curtain machine, so as not to be affected by frosting or defrosting and change, thereby ensuring a constant ambient temperature of an article in the air curtain and ensuring the quality of the article.
Example 7
The present embodiment provides a computer-readable storage medium on which a computer program is stored, which when executed by a processor implements the method in the above-described embodiments.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed 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 modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (13)
1. A fan frequency control method is applied to an air curtain machine and is characterized by comprising the following steps:
determining an operation mode of the air curtain machine; wherein the operating mode comprises at least one of: a refrigeration mode, a defrost mode;
acquiring the current air outlet speed of the air curtain machine;
adjusting the frequency of the fan according to the operation mode and the current air outlet speed; which comprises the following steps:
if the operation mode of the air curtain machine is a refrigeration mode, controlling the frequency of the fan to rise according to the current air outlet speed;
and if the operation mode of the air curtain machine is a defrosting mode, controlling the frequency of the fan to be reduced according to the current air outlet speed.
2. The method of claim 1, wherein obtaining the current outlet wind speed of the air curtain machine comprises:
acquiring the air outlet speeds of a plurality of detection points at preset time intervals; the detection points are all positioned on the air outlet side of the evaporator of the air curtain machine;
and calculating the average air outlet speed according to the air outlet speeds of the plurality of detection points to serve as the current air outlet speed.
3. The method according to claim 2, wherein the average wind speed is calculated from the wind speeds at the plurality of detection points according to the following formula:
wherein S isAt presentIs the current wind speed S1Is the wind speed at the first detection point, S2Is the wind speed at the second detection point, SnFor wind at the nth detection pointAnd n is the number of the detection points, a is the number of the data groups acquired within the preset time length, and i is the serial number of the data groups acquired within the preset time length.
4. The method of claim 1, wherein controlling the fan frequency to increase based on the current wind exit velocity comprises:
determining a first target fan frequency according to the difference value between the target air outlet speed and the current air outlet speed;
and controlling the fan to operate according to the first target fan frequency.
5. The method of claim 4, wherein the first target fan frequency is determined based on a difference between the target wind speed and the current wind speed according to the formula:
f(n1)＝f(0)+K*(Starget-SAt present)；
Wherein f (n1) is a first target fan frequency, f (0) is a current fan frequency, K is an adjustment coefficient, STargetIs the target air outlet speed, SAt presentThe current wind outlet speed.
6. The method of claim 3, wherein after controlling the fan frequency to increase according to the current wind outlet speed, the method further comprises:
judging whether the current fan frequency is greater than a frequency upper limit value or not;
if yes, triggering to enter a defrosting mode;
if not, triggering to adjust the fan frequency according to the operation mode and the current air outlet speed, and triggering to enter the defrosting mode after the current fan frequency is greater than the upper limit value of the frequency.
7. The method of claim 3, wherein controlling the fan frequency to decrease based on the current wind exit velocity comprises:
determining a second target fan frequency according to the difference value between the current air outlet speed and the target air outlet speed;
and controlling the fan to operate according to the second target fan frequency.
8. The method of claim 7, wherein the second target fan frequency is determined based on a difference between the current outlet wind speed and the target outlet wind speed according to the following formula:
f(n2)＝f(0)-K*(Sat present-STarget)；
Wherein f (n2) is the second target fan frequency, f (0) is the current fan frequency, K is the adjustment coefficient, STargetIs the target air outlet speed, SAt presentThe current wind outlet speed.
9. The method of claim 3, wherein after controlling the fan frequency to decrease according to the current wind outlet speed, the method further comprises:
judging whether the current fan frequency is smaller than a lower frequency limit value or not;
if yes, triggering to enter a cooling mode;
if not, triggering to adjust the fan frequency according to the operation mode and the current air outlet speed until the current fan frequency is smaller than the lower frequency limit value, and triggering to enter a refrigeration mode.
10. A fan frequency control apparatus for implementing the fan frequency control method according to any one of claims 1 to 9, the apparatus comprising:
the determining module is used for determining the operation mode of the air curtain machine; the operating mode includes at least one of: a refrigeration mode, a defrost mode;
the acquiring module is used for acquiring the current air outlet speed of the air curtain machine;
the adjusting module is used for adjusting the frequency of the fan according to the operation mode and the current air outlet speed; the adjusting module comprises a first adjusting unit and a second adjusting unit, wherein the first adjusting unit is used for controlling the frequency of the fan to be increased according to the current air outlet speed when the operation mode of the air curtain machine is a refrigerating mode; and the second adjusting unit is used for controlling the frequency of the fan to be reduced according to the current air outlet speed when the operation mode of the air curtain machine is a defrosting mode.
11. An air curtain machine comprising an evaporator and a fan, characterized by further comprising a fan frequency control device as claimed in claim 10.
12. A display case comprising the air curtain machine of claim 11.
13. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the method according to any one of claims 1 to 9.
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| US4346755A (en) * | 1980-05-21 | 1982-08-31 | General Electric Company | Two stage control circuit for reversible air cycle heat pump |
| KR0123429B1 (en) * | 1994-04-04 | 1997-11-15 | 김광호 | Refrigerator fan motor control method and circuit |
| CN202074654U (en) * | 2011-05-25 | 2011-12-14 | 西安市四腾工程有限公司 | Closed-loop control system for controlling constant air volume of purification air conditioner system |
| CN103912968B (en) * | 2013-01-04 | 2016-06-08 | 广东美的制冷设备有限公司 | A kind of conditioner permanent wind amount output control method and device |
| JP2017223406A (en) * | 2016-06-15 | 2017-12-21 | サンデンホールディングス株式会社 | Controller of showcase |
| CN207085941U (en) * | 2017-08-15 | 2018-03-13 | 广州泛美实验室系统科技股份有限公司 | A kind of hundred grades of Streamline cabinets of laboratory Intelligent adjustment |
| CN108613473B (en) * | 2018-04-02 | 2019-08-23 | 合肥美的电冰箱有限公司 | Wind cooling refrigerator and its control method of defrost, control system, controller |
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