Direct-cooling refrigerator, variable-frequency driving board of direct-cooling refrigerator, control method and storage medium

Abstract

The invention provides a direct-cooling refrigerator, a variable-frequency driving board of the direct-cooling refrigerator, a control method and a storage medium. In the direct-cooling refrigerator, a mechanical temperature controller is used for outputting a starting signal or a shutdown signal according to the temperature of an evaporator; the variable-frequency driving board is used for controlling the compressor to start up according to the start-up signal or controlling the compressor to start up according to the shutdown signal; the control method comprises the steps that in response to a starting-up signal obtained for the first time, a compressor is controlled to operate according to a preset gear so as to execute refrigeration for the first time; the energy efficiency of the compressor during operation at the preset gear is close to the maximum value of the direct-cooling refrigerator; in response to the start-up signal obtained at the ith time, the start-up rate of the compressor during refrigeration at the (i-1) th time and the previous gear of the compressor during shutdown at the (i-1) th time are obtained; i is an integer greater than or equal to 2; according to the starting rate and the previous gear, the operation gear of the compressor during ith refrigeration is determined; the compressor is controlled to operate according to the operation gear so as to execute the ith refrigeration; and controlling the compressor to stop in response to the shutdown signal.

Description

Technical Field

[0001] The present application relates to the technical field of refrigerators, and in particular to a direct cooling refrigerator and a variable frequency drive board, a control method and a storage medium thereof. Background Art

[0002] At present, the industry's traditional direct cooling machine-controlled single-system refrigerators all fail to meet freezing capacity performance indicators. At an ambient temperature of 25 degrees, after placing the refrigerated load, during the system's refrigeration operation, either the cold storage room temperature is too cold (below zero degrees), or the refrigeration load and pressure bin load cannot drop below -18 degrees within 24 hours, resulting in the failure of the freezing capacity performance indicators and the loss of food preservation and storage temperature in the cold storage room or freezer room.

[0003] Furthermore, direct-cooling refrigerators use mechanical temperature control technology to regulate temperature. Furthermore, they employ a fixed-speed compressor. A COP of 2.0 for a fixed-speed compressor is already very high, making it difficult to reduce energy consumption by simply increasing the COP. As consumers become more energy-conscious, the high energy consumption of mechanically controlled direct-cooling refrigerators has made their use more difficult.

[0004] Therefore, how to achieve frequency conversion of direct cooling refrigerators while ensuring that the direct cooling machine-controlled refrigerators meet the freezing performance test has become a technical problem that urgently needs to be solved in this field in order to meet energy-saving requirements. Summary of the Invention

[0005] The present application provides a direct cooling refrigerator and its variable frequency drive board, control method and storage medium, aiming to solve the technical problem of how to achieve frequency conversion of a direct cooling refrigerator while ensuring that the direct cooling machine-controlled refrigerator meets the freezing performance test.

[0006] In a first aspect, the present application provides a control method for a direct cooling refrigerator, the direct cooling refrigerator comprising an evaporator, a mechanical thermostat, a variable frequency drive board, and a compressor; the mechanical thermostat is configured to output a power-on signal or a power-off signal according to the temperature of the evaporator; the variable frequency drive board is configured to control the compressor to turn on according to the power-on signal or to turn off according to the power-off signal; the control method comprises:

[0007] In response to the first power-on signal obtained, controlling the compressor to operate at a preset gear to perform a first cooling operation; wherein the energy efficiency ratio of the compressor when operating at the preset gear is close to the maximum value of the direct cooling refrigerator and meets the freezing performance test requirements of the direct cooling refrigerator;

[0008] In response to the startup signal obtained for the i-th time, acquiring the startup rate of the compressor during the i-1-th cooling operation and the last gear position of the compressor during the i-1-th shutdown operation; wherein i is an integer greater than or equal to 2;

[0009] determining an operating gear of the compressor during the i-th cooling operation according to the on-time rate and the previous gear; wherein the on-time rate is positively correlated with an operating frequency or an operating speed corresponding to the operating gear;

[0010] Controlling the compressor to operate according to the operating gear to perform the i-th refrigeration;

[0011] In response to a shutdown signal, the compressor is controlled to stop.

[0012] Optionally, before obtaining the startup rate of the compressor during the (i-1)th cooling operation, the control method further includes:

[0013] In response to the power-on signal obtained for the i-th time, obtaining the power-on time of the compressor during the i-1-th cooling operation;

[0014] Obtain the downtime of the compressor from the time it stops after the (i-1)th cooling to the time it starts cooling for the i-th time;

[0015] According to the startup time and the shutdown time, the startup rate of the compressor during the i-1th cooling time is determined; wherein the startup rate during the i-1th cooling time is defined as t ％(i-1) The power-on time of the i-1th cooling is defined as t (i-1)开 The downtime t from the shutdown after the i-1th cooling to the start of cooling at the i-th time (i-1)停 ; Wherein, the startup rate during the i-1th cooling is determined in the following manner:

[0016]

[0017] Optionally, determining the operating gear of the compressor during the i-th cooling operation according to the startup rate and the previous gear includes:

[0018] Obtaining a gear position-on rate mapping relationship; wherein the gear position-on rate mapping relationship includes a mapping relationship between the range of the on rate and the variable gear position;

[0019] Determining a gear change value according to the on-rate and the gear-on-rate mapping relationship;

[0020] The operating gear is determined according to the gear change value and the previous gear.

[0021] Optionally, the compressor includes N gears; wherein N is a positive integer greater than 1; each gear corresponds to a different operating speed and operating frequency, and the operating speed and the operating frequency increase or decrease in sequence;

[0022] Determining the operating gear according to the gear change value and the previous gear includes:

[0023] determining a target gear position according to the gear position change value and the previous gear position;

[0024] If the gear value corresponding to the target gear is greater than N, then the operating gear is determined to be the Nth gear;

[0025] If the gear value corresponding to the target gear is less than 1, the operating gear is determined to be the first gear;

[0026] If the gear position corresponding to the target gear is between 1 and N, the operating gear is determined to be the target gear.

[0027] Optionally, the control method further includes:

[0028] When the compressor is started, obtaining the running time of the compressor;

[0029] The operating gear of the compressor is adjusted according to the gear-duration mapping relationship and the current gear of the compressor; wherein the operating duration is positively correlated with the operating speed corresponding to the operating gear.

[0030] The compressor is controlled to continue operating according to the adjusted operating gear.

[0031] Optionally, adjusting the operating gear of the compressor according to the gear-duration mapping relationship and the current gear of the compressor includes:

[0032] If the operating time is greater than the maximum operating time threshold, the operating gear of the compressor is adjusted to the highest gear; wherein the highest gear corresponds to the maximum operating speed of the compressor.

[0033] Optionally, before controlling the compressor to operate at a preset gear in response to the first power-on signal obtained to perform the first cooling, the control method further includes:

[0034] In response to a power-on signal, controlling the compressor to operate according to a preset mode;

[0035] The compressor is controlled to exit the preset mode.

[0036] In a second aspect, the present application further proposes a variable frequency drive board for a direct cooling refrigerator, the direct cooling refrigerator comprising an evaporator, a mechanical thermostat, and a compressor; the mechanical thermostat is configured to output a power-on signal or a power-off signal according to the temperature of the evaporator; the variable frequency drive board is configured to control the compressor to start up according to the power-on signal or to control the compressor to shut down according to the power-off signal; the variable frequency drive board comprises:

[0037] an acquisition module, configured to acquire a power-on signal and a power-off signal; and in response to the i-th acquired power-on signal, acquire the power-on rate of the compressor during the i-1th cooling operation and the last gear position of the compressor during the i-1th shutdown operation; wherein i is an integer greater than or equal to 2;

[0038] a control module, configured to, in response to the first power-on signal obtained, control the compressor to operate at a preset gear to perform a first cooling operation; wherein the energy efficiency ratio of the compressor when operating at the preset gear is close to the maximum value of the direct cooling refrigerator;

[0039] a determination module, configured to determine an operating gear of the compressor during the i-th cooling operation according to the startup rate and the previous gear;

[0040] The control module is configured to control the compressor to operate according to the operating gear to perform the i-th cooling operation;

[0041] The control module is further configured to control the compressor to stop in response to a shutdown signal.

[0042] On the third aspect, the present application also proposes a direct cooling refrigerator, which includes an evaporator, a mechanical thermostat, a variable frequency drive board and a compressor; the mechanical thermostat is used to output a power-on signal or a power-off signal according to the temperature of the evaporator; the variable frequency drive board is used to control the compressor to start up according to the power-on signal or to control the compressor to shut down according to the power-off signal; the variable frequency drive board is configured to execute the steps in the control method of the direct cooling refrigerator as described above.

[0043] In a fourth aspect, the present application further proposes a computer-readable storage medium on which a computer program is stored, and the computer program is loaded by a processor to perform the steps in the control method of the direct cooling refrigerator as described above.

[0044] In the technical solution of the embodiment of the present application, when the power-on signal is first obtained, the compressor operates according to the preset gear, so that the direct cooling refrigerator has a good energy-saving effect and can meet the indicators of the freezing performance test; and when the power-on signal is subsequently obtained, the operating gear of the compressor for this startup is determined based on the previous power-on rate and the previous gear when the compressor was shut down. The power-on rate represents the previous cooling condition of the direct cooling refrigerator. Under normal circumstances, the operating conditions of the i-1th cooling are basically consistent with the operating conditions of the refrigerator for the i-th cooling; at this time, the operating gear of this cooling is determined by the previous operating gear and the power-on rate, and the power-on rate is positively correlated with the speed corresponding to the operating gear, that is, the higher the previous power-on rate, the higher the operating speed during the next cooling, so as to dynamically adjust the operation of the direct cooling refrigerator to meet the energy-saving needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 This is a schematic structural diagram of a direct cooling refrigerator provided in an embodiment of the present application;

[0047] Figure 2 This is a flow chart of an embodiment of a control method for a direct cooling refrigerator provided in an embodiment of the present application;

[0048] Figure 3 This is a flow chart of an embodiment of determining the startup rate in the control method of the direct cooling refrigerator provided in the embodiment of the present application;

[0049] Figure 4 yes Figure 2 A schematic diagram of a sub-step of step S420;

[0050] Figure 5 yes Figure 4 A schematic diagram of a sub-step of step S423;

[0051] Figure 6 This is a flow chart of an embodiment of adjusting the current gear position in the control method of the direct cooling refrigerator provided in the embodiment of the present application;

[0052] Figure 7 This is a flow chart of an embodiment of a method for controlling a direct cooling refrigerator provided in an embodiment of the present application, in which a compressor enters a preset mode of operation;

[0053] Figure 8 It is a structural schematic diagram of the control device of the direct cooling refrigerator provided in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0056] In this application, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described in this application as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is given to enable any person skilled in the art to make and use the invention. In the following description, details are listed for the purpose of explanation. It should be understood that one of ordinary skill in the art will recognize that the invention can be practiced without these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0057] The embodiments of the present application provide a direct cooling refrigerator and a variable frequency drive board, a control method and a storage medium thereof, which are described in detail below.

[0058] In the technical solution of the embodiment of this application, Figure 1As shown, the direct cooling refrigerator includes a variable frequency drive board, an evaporator, a compressor and a mechanical thermostat. The mechanical thermostat is configured to output a power-on signal or a power-off signal according to the temperature of the evaporator. For example, the mechanical thermostat is provided on the evaporator, and the contacts thereon are opened or closed according to the temperature of the evaporator. When the contacts are disconnected, the signal path between the mechanical thermostat and the variable frequency drive board is disconnected, and a power-off signal is output to the variable frequency drive board; when the contacts are closed, the signal path between the mechanical thermostat and the variable frequency drive board is connected, and a power-on signal is output to the variable frequency drive board. The temperature at which the mechanical thermostat is disconnected or closed is set according to the system. In an embodiment, the mechanical thermostat can be divided into three gears, weak cooling temperature (-17±1°C), medium cooling temperature (-23±1°C) and strong cooling temperature (-29±1°C). For example, when the mechanical thermostat is in the weak cooling temperature position (taking -17°C as an example), when the evaporator temperature rises from below -17°C to -17°C, it means that the indoor temperature rises to the required cooling capacity. At this time, the mechanical thermostat contacts are closed and the power-on signal is input to the variable frequency drive board.

[0059] In an embodiment, the direct-cooling refrigerator further includes a condenser and a throttling device. A compressor is sequentially connected to the condenser, the throttling device, and the evaporator along the direction of refrigerant flow; the outlet of the evaporator is connected to the inlet of the compressor to form a refrigerant circulation system for the direct-cooling refrigerator.

[0060] In some embodiments, the variable frequency drive board converts the power-on signal or power-off signal input from the mechanical thermostat into a pulse signal through the control signal conversion circuit, and then sends a drive signal to control the startup and shutdown of the compressor.

[0061] In some embodiments, the mechanical thermostat setting is fixed after the freezing performance test and is no longer adjusted, meaning the freezing capacity of the direct-cooling refrigerator is fixed. To meet the standard freezing capacity requirements: at a 25°C ambient temperature, a 25°C freezing load of 3.5 kg per 100 L of freezer volume is loaded. Within 24 hours, the temperatures of all loaded freezing loads and ballast loads reach the preset values. Furthermore, from the time the freezing loads are loaded to the freezing point, the instantaneous temperatures at the top, middle, and bottom of the refrigerated compartment must not fall below 0°C. The mechanical thermostat setting cannot be adjusted from the time the freezing loads are loaded, and remains fixed.

[0062] In an embodiment of the present application, the operating gear of the compressor is configured to be adjustable, that is, the compressor is a variable frequency compressor. In the specific implementation process, the operating gear of the compressor is specifically set. Among them, the operating gear of the compressor includes a preset gear. The preset gear is determined when the direct cooling refrigerator is subjected to a freezing capacity performance test; at this preset gear, the energy efficiency ratio of the compressor is close to the maximum value, and the heat load and the direct cooling amount are well matched, so that the direct cooling refrigerator has a better energy-saving effect; that is, under the preset 25°C ambient temperature condition, the weight of the 25°C freezing load of 3.5kg per 100L of the freezer volume is loaded. At this preset gear, the direct cooling refrigerator can reduce the temperature of the freezer to the preset value with the lowest energy consumption.

[0063] For example, in a specific embodiment, the operating gear of the compressor includes a preset gear, which is the eighth gear. When the operating gear of the compressor is the eighth gear, the operating frequency of the compressor is 43 Hz and the operating speed is 2580 rpm.

[0064] Based on the introduction of the above embodiments, Figure 2 As shown, an embodiment of the present application provides a control method for a direct cooling refrigerator, the control method comprising:

[0065] S200, in response to the first power-on signal obtained, controlling the compressor to operate at a preset gear to perform a first cooling operation; wherein the energy efficiency ratio of the compressor when operating at the preset gear is close to the maximum value of the direct cooling refrigerator and meets the freezing performance test requirements of the direct cooling refrigerator;

[0066] S410, in response to the i-th acquired startup signal, acquiring the startup rate of the compressor during the i-1th cooling operation and the last gear position of the compressor during the i-1th shutdown operation; wherein i is an integer greater than or equal to 2;

[0067] S420, determining an operating gear of the compressor during the i-th cooling operation based on the on-rate and the previous gear; the on-rate is positively correlated with an operating frequency or an operating speed corresponding to the operating gear;

[0068] S430, controlling the compressor to operate according to the operating gear to perform the i-th cooling;

[0069] S600: In response to a shutdown signal, the compressor is controlled to stop.

[0070] In the technical solution of the embodiment of the present application, when the power-on signal is first obtained, the compressor operates according to the preset gear, so that the direct cooling refrigerator has a good energy-saving effect and can meet the indicators of the freezing performance test; and when the power-on signal is subsequently obtained, the operating gear of the compressor at the time of this startup is determined based on the previous power-on rate and the previous gear when the compressor was shut down. The power-on rate represents the previous cooling condition of the direct cooling refrigerator. Under normal circumstances, the operating conditions of the i-1th cooling are basically consistent with the operating conditions of the refrigerator during the i-th cooling; at this time, the operating gear of this cooling is determined by the previous operating gear and the power-on rate, and the power-on rate is positively correlated with the speed corresponding to the operating gear, that is, the higher the previous power-on rate, the higher the operating speed during the next cooling, so as to dynamically adjust the operation of the direct cooling refrigerator to meet the energy-saving needs.

[0071] In an embodiment, when a direct cooling refrigerator is cooled for the first time, it operates at a preset gear until a shutdown signal is obtained (at this time, the contacts of the mechanical thermostat reach the temperature corresponding to the temperature control gear due to the evaporator temperature), and the compressor stops running; however, when the contacts of the mechanical thermostat exceed the temperature corresponding to the temperature control gear due to the evaporator temperature, they are reclosed and a startup signal is generated. At this time, the direct cooling refrigerator is cooled for the second time, and the startup rate during the first cooling and the previous gear during the first shutdown are obtained to determine the operating gear for the second cooling; and so on, the start and stop of the compressor and the operating gear during operation are controlled.

[0072] like Figure 3 As shown, as an optional implementation of the above embodiment, before obtaining the startup rate of the compressor during the (i-1)th cooling, the control method further includes:

[0073] S310, in response to the power-on signal obtained for the i-th time, obtaining the power-on time of the compressor during the i-1-th cooling operation;

[0074] S320, obtaining the downtime of the compressor from the time it stops after the (i-1)th cooling operation to the time it starts cooling for the i-th time;

[0075] S330, determining an on-rate of the compressor during the (i-1)th cooling operation based on the on-time and the off-time.

[0076] The power-on rate during the i-1th cooling period is defined as t ％(i-1) The power-on time of the i-1th cooling is defined as t (i-1)开 The downtime t from the shutdown after the i-1th cooling to the start of cooling at the i-th time (i-1)停 ; Wherein, the startup rate during the i-1th cooling is determined in the following manner:

[0077]

[0078] In this embodiment, when the power-on signal is received for the i-th time, the compressor's power-on duration during the i-1th cooling cycle and the compressor's downtime duration from the time the compressor shuts down after the i-1th cooling cycle to the time the i-th cooling cycle begins are obtained, thereby determining the compressor's power-on rate during the i-1th cooling cycle using the above formula. As can be seen from the power-on rate formula, the power-on rate is positively correlated with power-on duration and negatively correlated with downtime. The longer the power-on duration, the higher the refrigerator's cooling demand; the longer the downtime, the slower the refrigerator's evaporator returns to a warm state, and the lower the cooling demand.

[0079] like Figure 4 As shown, as an optional implementation of the above embodiment, determining the operating gear of the compressor during the i-th cooling according to the startup rate and the previous gear includes:

[0080] S421, obtaining a gear position-on rate mapping relationship; wherein the gear position-on rate mapping relationship includes a mapping relationship between an on rate range and a variable gear position;

[0081] S422, determining a gear change value according to the on-rate and the gear-on-rate mapping relationship;

[0082] S423: Determine the operating gear according to the gear change value and the previous gear.

[0083] In an embodiment, the mapping relationship between the gear position and the power-on rate can refer to a mapping table of the gear position and the power-on rate, which is pre-stored in the memory. The mapping table of the gear position and the power-on rate is preset under the condition that the gear value increases and the frequency (speed) increases. The mapping table of the gear position and the power-on rate is shown in the following table:

[0084] On-time rate x Gear change value x＜50％ Downshift 4 gears (-4) 50％≤x＜60％ Downshift 3 gears (-3) 60％≤x＜70％ Downshift 2 gears (-2) 70％≤x＜76％ Downshift 1 gear (-1) 76％≤x＜84％ Keep 84％≤x＜93％ Add 1 level (+1) 93％≤x Plus 4 gears (+4)

[0085] The above compressor gear-on rate mapping table is merely an example and does not limit the scope of protection of this application. The specific range of the on-rate and the increase or decrease of gears are not specifically limited. For example, in other products, if 60% ≤ x < 80%, the current gear is maintained; if x ≥ 80%, the gear is increased by two; and if x ≤ 60%, the gear is decreased by one for every 10% decrease.

[0086] As shown in the table above, when the set gear value increases and the frequency (speed) increases, in the gear-on rate mapping table, the lower the on rate, the more gears are reduced, and the higher the on rate, the fewer gears are reduced or even increased. For example, the gear-frequency mapping table of the compressor is shown in the table below:

[0087] gear Frequency (Hz) Speed (rpm) 1 22 1320 2 24 1440 3 26 1560 4 29 1740 5 32 1920 6 35 2100 7 38 2280 8 43 2580 9 47 2820 10 61 3660 11 72 4320

[0088] The above compressor gear-frequency mapping table is only an example and does not limit the scope of protection of this application. For example, gear 1 may correspond to 22 Hz, while in other products, gear 1 may correspond to 24 Hz. For another example, the compressor gear may be 11 gears, while in other products, the compressor may be further divided into 15 gears or other gears.

[0089] For example, in a specific embodiment, when the power-on signal is obtained for the first time, the compressor operates at the preset gear (eighth gear) and the power-on rate is 78%; when the power-on signal is obtained for the second time, the compressor still operates at the eighth gear.

[0090] For example, in a specific embodiment, when the power-on signal is obtained for the second time, the compressor operates at the eighth gear and the power-on rate is 45%; then when the power-on signal is obtained for the third time, the compressor needs to reduce the operation by 4 gears and operate at the fourth gear.

[0091] For example, in a specific embodiment, when the power-on signal is obtained for the i-1th time, the compressor is running at the 6th gear and the power-on rate is 88%; then when the power-on signal is obtained for the i-th time, the compressor needs to increase the running speed by 1 gear and run at the 7th gear.

[0092] By dynamically adjusting the operation of the compressor through the mapping relationship between the start-up rate and the gear change value, the compressor can dynamically adapt to load changes and environmental changes during the refrigeration process, so as to accurately achieve a good match between the cooling capacity and the heat load, thereby effectively saving energy.

[0093] As an optional implementation of the above embodiment, the compressor includes N gears; wherein N is a positive integer greater than 1; each gear corresponds to a different operating speed and operating frequency, and the operating speed and the operating frequency increase or decrease in sequence;

[0094] like Figure 5 As shown, determining the operating gear according to the gear change value and the previous gear includes:

[0095] S4231, determining a target gear position according to the gear position change value and the previous gear position;

[0096] S4232, if the gear value corresponding to the target gear is greater than N, determining that the operating gear is the Nth gear;

[0097] S4233, if the gear value corresponding to the target gear is less than 1, determining that the operating gear is the first gear;

[0098] S4234: If the gear position corresponding to the target gear is between 1 and N, determine that the operating gear is the target gear.

[0099] In this embodiment, for example, in a specific embodiment, during the i-1th cooling, the compressor operates at the 2nd gear, and the power-on rate is 45%; then when the power-on signal is obtained for the i-1th time, the compressor needs to reduce the operation by 4 gears, and the target gear is -2 gear at this time, and the gear value is less than 1 gear; that is, the lowest gear of the direct cooling refrigerator is 1 gear, and at this time, the operating gear is determined to be 1 gear.

[0100] For example, in a specific embodiment, during the i-1th cooling, the compressor operates at the 9th gear and the power-on rate is 95%; then when the power-on signal is obtained for the i-th time, the compressor needs to increase the operation by 4 gears. At this time, the target gear is 13, and the gear value is greater than 11; that is, the highest gear of the direct cooling refrigerator is 111, and the operating gear is determined to be 11 at this time.

[0101] For example, in a specific embodiment, when cooling is obtained for the i-1th time, the compressor operates at the 6th gear and the power-on rate is 88%; then when the power-on signal is obtained for the i-th time, the compressor needs to increase the gear by 1 and the gear value of the target gear is 7, which is between 1 and 11. At this time, the compressor operates at the 7th gear.

[0102] That is, when the gear value of the target gear is lower than the lowest gear or the highest gear, the operating gear runs at the lowest gear or the highest gear.

[0103] As an optional implementation of the above embodiment, Figure 6 As shown, the control method further includes:

[0104] S510, when the compressor is started, obtaining the operating time of the compressor;

[0105] S520, adjusting the operating gear of the compressor according to the gear-duration mapping relationship and the current gear of the compressor; wherein the operating duration is positively correlated with the operating speed corresponding to the operating gear.

[0106] S530, controlling the compressor to continue operating according to the adjusted operating gear.

[0107] In an embodiment, during the operation of the compressor, its operating time is affected by changes in the heat load. Generally, the heat load comes from the load, human operation and ambient temperature. Since the ambient temperature is in a steady state for a short time, the amount and temperature of the load and human operation are the main factors causing the change in the heat load. When the load amount is greater than the previous load amount (heat load increases) or the user opens the compartment door for a long time (heat load increases) during a certain refrigeration, and the operating gear at this time is determined based on the last power-on rate and the previous gear, there is a certain mismatch between the cooling capacity and the newly added heat load (that is, the heat load of the refrigerator becomes unstable). At this time, the operating time of the compressor increases. When the continuous operation time exceeds a certain value, the current gear will be adjusted to increase the cooling capacity so that the compartment reaches the required temperature faster.

[0108] Refer to the gear-duration mapping relationship shown below:

[0109]

[0110] In one specific embodiment, when the cooling signal is obtained for the i-1th time, the compressor is operating at gear 6, with an on-rate of 88%. Then, when the on-rate signal is obtained for the i-th time, the compressor needs to increase its gear by one, and the target gear value is 7, which is between 1 and 11. At this time, the compressor is operating at gear 7. During the i-th operation, if the continuous operation time reaches 80 minutes, the operation is increased to gear 9; if the continuous operation time reaches 100 minutes, the operation is increased to gear 11 (which is already the highest gear, so it is operated at the highest gear).

[0111] In one specific embodiment, when the cooling signal is obtained for the i-1th time, the compressor is operating at gear 6 with an on-rate of 45%. Then, when the on-rate signal is obtained for the i-th time, the compressor needs to reduce its operation by 4 gears, and the target gear value is 2, which is between 1 and 11. At this time, the compressor is operating at gear 2. During the i-th operation, if the continuous operation time reaches 80 minutes, the operation is increased to gear 4; if the continuous operation time reaches 100 minutes, the operation is increased to gear 6; if the continuous operation time reaches 120 minutes, the operation is increased to gear 8; if the continuous operation time reaches 140 minutes, the operation is increased to gear 10; and if the continuous operation time reaches 160 minutes, the operation is increased to the highest gear.

[0112] The above compressor gear-duration mapping table is merely an example and does not limit the scope of protection of this application. For example, when the continuous operation time reaches 60 minutes, one gear is added; when the continuous operation time reaches 90 minutes, three gears are added to the gear after the first gear was added (the additional gears do not exceed the highest gear); when the continuous operation time reaches 150 minutes, five gears are added after the first and third gears were added (the additional gears do not exceed the highest gear).

[0113] As an optional implementation manner of the above embodiment, adjusting the operating gear of the compressor according to the gear-duration mapping relationship and the current gear of the compressor includes:

[0114] If the operating time is greater than the maximum operating time threshold, the operating gear of the compressor is adjusted to the highest gear; wherein the highest gear corresponds to the maximum operating speed of the compressor.

[0115] In this embodiment, when the operating time is greater than the maximum operating time threshold, such as 160 minutes in the above table, the compressor is adjusted to run at the highest gear to quickly cool the evaporator and quickly cool the compartment.

[0116] As an optional implementation of the above embodiment, Figure 7 As shown, in response to the first power-on signal obtained, before controlling the compressor to operate according to a preset gear to perform the first cooling, the control method further includes:

[0117] S110, in response to a power-on signal, controlling the compressor to operate according to a preset mode;

[0118] S120, controlling the compressor to exit the preset mode.

[0119] In this embodiment, after receiving a power-on signal, the compressor operates according to a preset mode. This serves both to test the compressor and to lower the evaporator temperature to a suitable temperature, preventing the direct-cooling refrigerator from entering operating mode and protecting the compressor and refrigerant system. After the compressor operates according to the preset mode, a shutdown signal is generated by the mechanical thermostat's power-on signal, allowing the compressor to resume normal cooling mode.

[0120] In some embodiments, in a preset mode, the compressor operates at at least two operating frequencies (operating speeds) for a first preset duration and a second preset duration, respectively. For example, the compressor operates at 45 Hz (2700 rpm) for 30 minutes, then increases to 55 Hz (3300 rpm) for 30 minutes, then increases to 72 Hz (4320 rpm), and continues to operate at this speed until a shutdown condition is met, then exits the initial power-on mode. This continues until the mechanical thermostat inputs the first power-on signal to the variable frequency drive board, at which point the compressor begins operating at the preset gear.

[0121] In some embodiments, the power-on signal may be the first power-on of the refrigerator to the user side, or the power-on of the refrigerator after a power outage.

[0122] In order to better implement the control method of the direct cooling refrigerator in the embodiment of the present application, based on the control method of the direct cooling refrigerator, the embodiment of the present application further provides a variable frequency drive board, such as Figure 8 As shown, the variable frequency drive board includes:

[0123] An acquisition module 10 is configured to acquire a power-on signal and a power-off signal; and in response to the i-th acquired power-on signal, acquire the power-on rate of the compressor during the i-1th cooling operation and the last gear position of the compressor during the i-1th shutdown operation; wherein i is an integer greater than or equal to 2;

[0124] The control module 20 is configured to control the compressor to operate at a preset gear in response to the first power-on signal obtained, so as to perform a first cooling operation; wherein the energy efficiency ratio of the compressor when operating at the preset gear is close to the maximum value of the direct cooling refrigerator;

[0125] a determination module 30, configured to determine an operating gear of the compressor during the i-th cooling operation according to the startup rate and the previous gear;

[0126] The control module is configured to control the compressor to operate according to the operating gear to perform the i-th cooling operation;

[0127] The control module is further configured to control the compressor to stop in response to a shutdown signal.

[0128] An embodiment of the present application also proposes a control system for a direct cooling refrigerator, comprising: one or more processors; a memory; and one or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the processor to implement the control method of the direct cooling refrigerator as described above.

[0129] Generally speaking, usually, the control system of the direct cooling refrigerator includes: at least one processor, at least one memory, and a control program of the control system of the direct cooling refrigerator stored in the memory and executable on the processor. The control program of the control system of the direct cooling refrigerator is configured to implement the steps of the previous control method.

[0130] The processor may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor may be implemented in at least one of the following hardware forms: a DSP (Digital Signal Processing), an FPGA (Field-Programmable Gate Array), or a PLA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content required to be displayed on the display screen. The processor may also include an AI (Artificial Intelligence) processor, which is used to process the control method operations related to the direct cooling refrigerator control system, so that the control method model of the direct cooling refrigerator control system can be autonomously trained and learned to improve efficiency and accuracy.

[0131] The memory may include one or more computer-readable storage media, which may be non-transitory. The memory may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory is used to store at least one instruction, which is used to be executed by the processor to implement the control method of the direct cooling refrigerator provided in the method embodiment of the present application.

[0132] In response to the first power-on signal obtained, the compressor is controlled to operate at a preset gear to perform a first cooling operation; wherein the energy efficiency ratio of the compressor when operating at the preset gear is close to the maximum value of the direct cooling refrigerator;

[0133] In response to the startup signal obtained for the i-th time, acquiring the startup rate of the compressor during the i-1-th cooling operation and the last gear position of the compressor during the i-1-th shutdown operation; wherein i is an integer greater than or equal to 2;

[0134] determining an operating gear of the compressor during the i-th cooling operation according to the on-time rate and the previous gear; wherein the on-time rate is positively correlated with an operating frequency or an operating speed corresponding to the operating gear;

[0135] Controlling the compressor to operate according to the operating gear to perform the i-th refrigeration;

[0136] In response to a shutdown signal, the compressor is controlled to stop.

[0137] Optionally, before obtaining the startup rate of the compressor during the (i-1)th cooling operation, the control method further includes:

[0138] In response to the power-on signal obtained for the i-th time, obtaining the power-on time of the compressor during the i-1-th cooling operation;

[0139] Obtain the downtime of the compressor from the time it stops after the (i-1)th cooling to the time it starts cooling for the i-th time;

[0140] According to the startup time and the shutdown time, the startup rate of the compressor during the i-1th cooling time is determined; wherein the startup rate during the i-1th cooling time is defined as t ％(i-1) The power-on time of the i-1th cooling is defined as t (i-1)开 The downtime t from the shutdown after the i-1th cooling to the start of cooling at the i-th time (i-1)停 ; Wherein, the startup rate during the i-1th cooling is determined in the following manner:

[0141]

[0142] Optionally, determining the operating gear of the compressor during the i-th cooling operation according to the startup rate and the previous gear includes:

[0143] Obtaining a gear position-on rate mapping relationship; wherein the gear position-on rate mapping relationship includes a mapping relationship between the range of the on rate and the variable gear position;

[0144] Determining a gear change value according to the on-rate and the gear-on-rate mapping relationship;

[0145] The operating gear is determined according to the gear change value and the previous gear.

[0146] Optionally, the compressor includes N gears; wherein N is a positive integer greater than 1; each gear corresponds to a different operating speed and operating frequency, and the operating speed and the operating frequency increase or decrease in sequence;

[0147] Determining the operating gear according to the gear change value and the previous gear includes:

[0148] determining a target gear position according to the gear position change value and the previous gear position;

[0149] If the gear value corresponding to the target gear is greater than N, then the operating gear is determined to be the Nth gear;

[0150] If the gear value corresponding to the target gear is less than 1, the operating gear is determined to be the first gear;

[0151] If the gear position corresponding to the target gear is between 1 and N, the operating gear is determined to be the target gear.

[0152] Optionally, the control method further includes:

[0153] When the compressor is started, obtaining the running time of the compressor;

[0154] The operating gear of the compressor is adjusted according to the gear-duration mapping relationship and the current gear of the compressor; wherein the operating duration is positively correlated with the operating speed corresponding to the operating gear.

[0155] The compressor is controlled to continue operating according to the adjusted operating gear.

[0156] Optionally, adjusting the operating gear of the compressor according to the gear-duration mapping relationship and the current gear of the compressor includes:

[0157] If the operating time is greater than the maximum operating time threshold, the operating gear of the compressor is adjusted to the highest gear; wherein the highest gear corresponds to the maximum operating speed of the compressor.

[0158] Optionally, before controlling the compressor to operate at a preset gear in response to the first power-on signal obtained to perform the first cooling, the control method further includes:

[0159] In response to a power-on signal, controlling the compressor to operate according to a preset mode;

[0160] The compressor is controlled to exit the preset mode.

[0161] The above is a detailed introduction to a direct cooling refrigerator and its variable frequency drive board, control method and computer-readable storage medium provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A control method for a direct cooling refrigerator, characterized in that: The direct cooling refrigerator includes an evaporator, a mechanical thermostat, a variable frequency drive board, and a compressor; the mechanical thermostat is used to output a power-on signal or a power-off signal according to the temperature of the evaporator; the variable frequency drive board is used to control the compressor to start up according to the power-on signal or to control the compressor to shut down according to the power-off signal; the control method includes: In response to the first power-on signal obtained, controlling the compressor to operate at a preset gear to perform a first cooling operation; wherein the energy efficiency ratio of the compressor when operating at the preset gear is close to the maximum value of the direct cooling refrigerator and meets the freezing performance test requirements of the direct cooling refrigerator; In response to the startup signal obtained for the i-th time, acquiring the startup rate of the compressor during the i-1-th cooling operation and the last gear position of the compressor during the i-1-th shutdown operation; wherein i is an integer greater than or equal to 2; determining an operating gear of the compressor during the i-th cooling operation according to the on-time rate and the previous gear; wherein the on-time rate is positively correlated with an operating frequency or an operating speed corresponding to the operating gear; Controlling the compressor to operate according to the operating gear to perform the i-th refrigeration; In response to a shutdown signal, the compressor is controlled to stop.

2. The control method according to claim 1, wherein: Before obtaining the startup rate of the compressor during the (i-1)th cooling operation, the control method further includes: In response to the power-on signal obtained for the i-th time, obtaining the power-on time of the compressor during the i-1-th cooling operation; Obtain the downtime of the compressor from the time it stops after the (i-1)th cooling to the time it starts cooling for the i-th time; According to the startup time and the shutdown time, the startup rate of the compressor during the i-1th cooling time is determined; wherein the startup rate during the i-1th cooling time is defined as t ％(i-1) The power-on time of the i-1th cooling is defined as t (i-1)开 The downtime t from the shutdown after the i-1th cooling to the start of cooling at the i-th time (i-1)停 ; Wherein, the startup rate during the i-1th cooling is determined in the following manner:

3. The control method according to claim 1 or 2, characterized in that: Determining the operating gear of the compressor during the i-th cooling operation according to the startup rate and the previous gear includes: Obtaining a gear position-on rate mapping relationship; wherein the gear position-on rate mapping relationship includes a mapping relationship between the range of the on rate and the variable gear position; Determining a gear change value according to the on-rate and the gear-on-rate mapping relationship; The operating gear is determined according to the gear change value and the previous gear.

4. The control method according to claim 3, wherein: The compressor includes N gears; wherein N is a positive integer greater than 1; each gear corresponds to a different operating speed and operating frequency, and the operating speed and the operating frequency increase or decrease in sequence; Determining the operating gear according to the gear change value and the previous gear includes: determining a target gear position according to the gear position change value and the previous gear position; If the gear value corresponding to the target gear is greater than N, then the operating gear is determined to be the Nth gear; If the gear value corresponding to the target gear is less than 1, the operating gear is determined to be the first gear; If the gear position corresponding to the target gear is between 1 and N, the operating gear is determined to be the target gear.

5. The control method according to claim 1, wherein: The control method further includes: When the compressor is started, obtaining the running time of the compressor; Adjusting the operating gear of the compressor according to the gear-duration mapping relationship and the current gear of the compressor; wherein the operating duration is positively correlated with the operating speed corresponding to the operating gear; The compressor is controlled to continue operating according to the adjusted operating gear.

6. The control method according to claim 5, wherein: Adjusting the operating gear of the compressor according to the gear-duration mapping relationship and the current gear of the compressor includes: If the operating time is greater than the maximum operating time threshold, the operating gear of the compressor is adjusted to the highest gear; wherein the highest gear corresponds to the maximum operating speed of the compressor.

7. The control method according to claim 1, wherein: Before controlling the compressor to operate according to a preset gear in response to the first acquired power-on signal to perform the first cooling, the control method further includes: In response to a power-on signal, controlling the compressor to operate according to a preset mode; The compressor is controlled to exit the preset mode.

8. A variable frequency drive board for a direct cooling refrigerator, characterized in that: The direct cooling refrigerator includes an evaporator, a mechanical thermostat, and a compressor; the mechanical thermostat is used to output a power-on signal or a power-off signal according to the temperature of the evaporator; the variable frequency drive board is used to control the compressor to start according to the power-on signal or to control the compressor to stop according to the power-off signal; The variable frequency drive board includes: an acquisition module, configured to acquire a power-on signal and a power-off signal; and in response to the i-th acquired power-on signal, acquire the power-on rate of the compressor during the i-1th cooling operation and the last gear position of the compressor during the i-1th shutdown operation; wherein i is an integer greater than or equal to 2; a control module, configured to, in response to the first power-on signal obtained, control the compressor to operate at a preset gear to perform a first cooling operation; wherein the energy efficiency ratio of the compressor when operating at the preset gear is close to the maximum value of the direct cooling refrigerator; a determination module, configured to determine an operating gear of the compressor during the i-th cooling operation according to the startup rate and the previous gear; The control module is configured to control the compressor to operate according to the operating gear to perform the i-th cooling operation; The control module is further configured to control the compressor to stop in response to a shutdown signal.

9. A direct cooling refrigerator, characterized in that: The direct cooling refrigerator includes an evaporator, a mechanical thermostat, a variable frequency drive board and a compressor; the mechanical thermostat is used to output a power-on signal or a power-off signal according to the temperature of the evaporator; the variable frequency drive board is used to control the compressor to start up according to the power-on signal or to control the compressor to shut down according to the power-off signal; the variable frequency drive board is configured to execute the steps in the control method of the direct cooling refrigerator described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that A computer program is stored thereon, and the computer program is loaded by a processor to execute the steps in the control method of the direct cooling refrigerator according to any one of claims 1 to 7.

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