Methods, devices and refrigeration systems for speed step control of variable frequency compressors

Abstract

This invention discloses a speed step size control method, device, and refrigeration system for a variable frequency compressor. The variable frequency compressor is applied to environmental testing equipment. The speed step size control method includes: acquiring the current temperature of the inner chamber of the environmental testing equipment and the temperature at a preset time prior to the current time; determining the rate of change of the current temperature and the temperature at the preset time based on the current temperature and the temperature at the preset time; and controlling the speed step size of the variable frequency compressor based on the rate of change, a preset speed step size control deviation, and a preset step size correction value. The speed step size control method, device, and refrigeration system for a variable frequency compressor provided by this invention can reduce energy consumption and improve energy-saving effects.

Description

Technical Field

[0001] The embodiments of the present invention relate to compressor control technology, and more particularly to a method, device and refrigeration system for controlling the speed step size of a variable frequency compressor. Background Technology

[0002] Refrigeration systems are indispensable for items, equipment, or spaces that require cooling. The compressor, as the heart of the refrigeration system, is also an essential component. Inverter compressors, for example, adjust their speed according to actual needs, achieving speed adjustment through step-by-step control.

[0003] Currently, existing variable frequency compressor speed step size control methods often suffer from low reliability when adjusting the speed step size, such as increasing the speed step size. This results in higher energy consumption for the variable frequency compressor and affects its energy-saving effect. Summary of the Invention

[0004] This invention provides a method, device, and refrigeration system for controlling the speed step size of a variable frequency compressor, in order to reduce energy consumption and improve energy-saving effect.

[0005] In a first aspect, embodiments of the present invention provide a speed step control method for a variable frequency compressor, wherein the variable frequency compressor is applied to environmental testing equipment, and the speed step control method includes:

[0006] Obtain the current temperature of the inner chamber of the environmental testing equipment and the temperature at a preset time before the current time;

[0007] Determine the rate of change of the current temperature and the temperature at the preset time based on the current temperature and the temperature at the preset time.

[0008] The speed step size of the variable frequency compressor is controlled based on the rate of change, the preset speed step size control deviation, and the preset step size correction value.

[0009] Optionally, based on the current temperature and the temperature at a preset time, determine the rate of change of the current temperature and the temperature at the preset time, including:

[0010] Based on the current temperature and the temperature at the preset time, determine the difference between the current temperature and the temperature at the preset time, as well as the time difference between the current time and the preset time;

[0011] The ratio of the difference to the time difference is used as the rate of change.

[0012] Optionally, the preset step size correction values ​​include a preset fourth step size correction value and a preset fifth step size correction value;

[0013] The speed step size of the variable frequency compressor is controlled based on the rate of change, the preset speed step size control deviation, and the preset step size correction value, including:

[0014] If the rate of change is greater than or equal to the preset speed step size control deviation, the preset minimum adjustment value of the speed step size is adjusted to the product of the preset fourth step size correction value and the absolute value of the rate of change (rounded to two decimal places), plus the preset fifth step size correction value.

[0015] Adjust the speed step size of the variable frequency compressor according to the preset minimum adjustment value of the speed step size.

[0016] Optionally, the speed step size of the variable frequency compressor can be adjusted according to a preset minimum adjustment value, including:

[0017] If the preset minimum adjustment value of the speed step size is less than or equal to the preset minimum speed change step size, then the preset minimum adjustment value will be adjusted to the preset minimum speed change step size.

[0018] If the preset minimum adjustment value of the speed step is less than or equal to the preset maximum speed change step, then the preset minimum adjustment value at this time will be used as the speed step of the variable frequency compressor.

[0019] Optionally, the speed step size of the variable frequency compressor can be adjusted according to a preset minimum adjustment value, including:

[0020] If the preset minimum adjustment value of the speed step is greater than the preset minimum speed change step and less than or equal to the preset maximum speed change step, then the preset minimum adjustment value at this time will be used as the speed step of the variable frequency compressor.

[0021] If the preset minimum adjustment value of the speed step size is greater than the preset maximum value of the speed change step size, then the preset maximum value of the speed change step size will be used as the speed step size of the variable frequency compressor.

[0022] Optionally, both the preset minimum and maximum speed change step sizes are the values ​​corresponding to the increase in step size.

[0023] Secondly, embodiments of the present invention also provide a speed step control device for a variable frequency compressor, wherein the variable frequency compressor is applied to environmental testing equipment, and the speed step control device includes:

[0024] The temperature acquisition module is used to acquire the current temperature of the inner chamber of the environmental testing equipment and the temperature at a preset time before the current time.

[0025] The rate determination module is used to determine the rate of change of the current temperature and the temperature at the preset time based on the current temperature and the temperature at the preset time.

[0026] The step size control module is used to control the speed step size of the variable frequency compressor based on the rate of change, the preset speed step size control deviation, and the preset step size correction value.

[0027] Optionally, the rate determination module includes:

[0028] The difference determination unit is used to determine the difference between the current temperature and the temperature at the preset time, as well as the time difference between the current time and the preset time, based on the current temperature and the temperature at the preset time.

[0029] The rate determination unit is used to determine the rate of change by taking the ratio of the difference to the time difference.

[0030] Thirdly, embodiments of the present invention also provide a refrigeration system, including a controller, a variable frequency compressor, a condenser, and an evaporator. The controller is electrically connected to the variable frequency compressor. The condenser is connected to the evaporator and the variable frequency compressor via pipelines. The evaporator is connected to the variable frequency compressor via pipelines. The speed step control device as described in the second aspect is integrated into the controller.

[0031] Optionally, the refrigeration system may also include an electronic expansion valve, which is located in the passage connecting the evaporator and the inverter compressor.

[0032] The present invention provides a method, apparatus, and refrigeration system for controlling the speed step size of a variable frequency compressor. The variable frequency compressor is applied to an environmental testing device. The method acquires the current temperature of the inner chamber of the environmental testing device and the temperature at a preset time prior to the current time. Based on the current temperature and the temperature at the preset time, the rate of change of the current temperature and the temperature at the preset time are determined. Based on the rate of change, a preset speed step size control deviation, and a preset step size correction value, the speed step size of the variable frequency compressor is controlled. The method, apparatus, and refrigeration system provided by the present invention, by controlling the speed step size of the variable frequency compressor based on the determined rate of change of the current temperature and the temperature at the preset time, a preset speed step size control deviation, and a preset step size correction value, can improve the reliability of the speed step size control of the variable frequency compressor, thereby saving energy and improving energy-saving effects. Attached Figure Description

[0033] Figure 1 This is a flowchart of a speed step control method for a variable frequency compressor provided in Embodiment 1 of the present invention;

[0034] Figure 2 This is a structural block diagram of a refrigeration system provided in Embodiment 1 of the present invention;

[0035] Figure 3 This is a flowchart of a speed step control method for a variable frequency compressor provided in Embodiment 2 of the present invention;

[0036] Figure 4This is a structural block diagram of a refrigeration system provided in Embodiment 2 of the present invention;

[0037] Figure 5 This is a flowchart of another speed step control method for a variable frequency compressor provided in Embodiment 2 of the present invention;

[0038] Figure 6 This is a structural block diagram of a speed step control device for a variable frequency compressor provided in Embodiment 3 of the present invention. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0040] Example 1

[0041] Figure 1 This is a flowchart of a speed step size control method for a variable frequency compressor provided in Embodiment 1 of the present invention. This embodiment is applicable to situations where the speed step size of the variable frequency compressor is increased. The variable frequency compressor is used in environmental testing equipment. This method can be executed by a speed step size control device for the variable frequency compressor. This device can be implemented by software and / or hardware. The device can be integrated into the controller of the refrigeration system. The method specifically includes the following steps:

[0042] Step 110: Obtain the current temperature of the inner chamber of the environmental testing equipment and the temperature at a preset time before the current time.

[0043] The current temperature and the temperature at a preset time before the current time can be collected in real time by a temperature sensor installed inside the environmental test equipment. The speed step control device is electrically connected to the temperature sensor to obtain the current temperature and the temperature at a preset time before the current time inside the environmental test equipment.

[0044] Step 120: Determine the rate of change of the current temperature and the temperature at the preset time based on the current temperature and the temperature at the preset time.

[0045] Specifically, the rate of change of the current temperature TPV(n) and the preset temperature TPV(nx) is [TPV(n)-TPV(nx)] / [t(n)-t(nx)], where t(n) is the current time and t(nx) is the preset time.

[0046] Step 130: Control the speed step of the variable frequency compressor according to the rate of change, the preset speed step control deviation, and the preset step correction value.

[0047] For example, Figure 2 This is a schematic diagram of a refrigeration system provided in Embodiment 1 of the present invention. (Reference) Figure 2 The refrigeration system includes a controller 10, a variable frequency compressor 20, a condenser, and an evaporator 30. The controller 10 is electrically connected to the variable frequency compressor 20. The condenser is connected to the evaporator 30 and the variable frequency compressor 20 via pipelines. The evaporator 30 is also connected to the variable frequency compressor 20 via pipelines. The speed step size control device, as described in any embodiment of the present invention, is integrated into the controller 10. The controller 10 can control the magnitude of the speed step size increase of the variable frequency compressor 20. For example, when the rate of change is greater than or equal to the preset speed step size control deviation, the preset minimum adjustment value of the speed step size is adjusted. If the preset minimum adjustment value is less than or equal to the preset maximum speed change step size, the preset minimum adjustment value at this time is used as the speed step size of the variable frequency compressor.

[0048] It should be noted that each preset value in this embodiment can be set according to the actual speed step size control requirements, and is not limited here.

[0049] The variable frequency compressor speed step size control method provided in this embodiment obtains the current temperature of the inner chamber of the environmental test equipment and the temperature at a preset time before the current time; determines the rate of change of the current temperature and the temperature at the preset time based on the current temperature and the temperature at the preset time; and controls the speed step size of the variable frequency compressor based on the rate of change, the preset speed step size control deviation, and the preset step size correction value. This variable frequency compressor speed step size control method, by controlling the speed step size of the variable frequency compressor based on the determined rate of change of the current temperature and the temperature at the preset time, the preset speed step size control deviation, and the preset step size correction value, can improve the reliability of the speed step size control of the variable frequency compressor, thereby saving energy and improving energy-saving effect.

[0050] Example 2

[0051] Figure 3 This is a flowchart of a speed step size control method for a variable frequency compressor provided in Embodiment 2 of the present invention. This embodiment is applicable to situations where the speed step size of the variable frequency compressor is increased. The variable frequency compressor is used in environmental testing equipment. This method can be executed by a speed step size control device for the variable frequency compressor. This device can be implemented by software and / or hardware. The device can be integrated into the controller of the refrigeration system. The method specifically includes the following steps:

[0052] Step 210: Obtain the current temperature of the inner chamber of the environmental testing equipment and the temperature at a preset time before the current time.

[0053] Step 220: Based on the current temperature and the temperature at the preset time, determine the difference between the current temperature and the temperature at the preset time, as well as the time difference between the current time and the preset time.

[0054] Step 230: Use the ratio of the difference to the time difference as the rate of change.

[0055] Step 240: If the rate of change is greater than or equal to the preset speed step size control deviation, then the preset minimum adjustment value of the speed step size is adjusted to the value obtained by multiplying the preset fourth step size correction value and the absolute value of the rate of change (rounded to two decimal places) by the preset fifth step size correction value.

[0056] The preset step size correction value includes a preset fourth step size correction value and a preset fifth step size correction value.

[0057] Step 250: If the preset minimum adjustment value of the speed step is less than or equal to the preset minimum speed change step, then adjust the preset minimum adjustment value to the preset minimum speed change step.

[0058] Step 260: If the preset minimum adjustment value of the speed step is less than or equal to the preset maximum speed change step, then the preset minimum adjustment value at this time shall be used as the speed step of the variable frequency compressor.

[0059] Step 270: If the preset minimum adjustment value of the speed step is greater than the preset minimum speed change step and less than or equal to the preset maximum speed change step, then the preset minimum adjustment value at this time shall be used as the speed step of the variable frequency compressor.

[0060] Step 280: If the preset minimum adjustment value of the speed step is greater than the preset maximum value of the speed change step, then the preset maximum value of the speed change step is used as the speed step of the variable frequency compressor.

[0061] Among them, the preset minimum speed change step size and the preset maximum speed change step size are the values ​​corresponding to the increase of the step size.

[0062] For example, Figure 4 This is a schematic diagram of a refrigeration system provided in Embodiment 2 of the present invention. The controller 10 in the refrigeration system controls the speed step size of the variable frequency compressor 20, such as controlling the speed step size of the variable frequency compressor 20 to be △rpm_step_increase_max, where △rpm_step_increase_max is a preset maximum value of the speed change step size.

[0063] Figure 5 This is a flowchart of another speed step control method for a variable frequency compressor provided in Embodiment 2 of the present invention. (See reference) Figure 5 The method includes the following steps:

[0064] Step 1: Obtain the current temperature TPV(n) of the inner chamber of the environmental testing equipment and the temperature TPV(nx) at a preset time before the current time.

[0065] Step 2: Determine the rate of change of the current temperature and the temperature at the preset time as dTPV_t_diff as [TPV(n)-TPV(nx)] / [t(n)-t(nx)].

[0066] Where t(n) is the current time and t(nx) is the preset time.

[0067] Step 3: Determine whether [TPV(n)-TPV(nx)] / [t(n)-t(nx)] is greater than or equal to dTPV_t_diff_con_in; if yes, proceed to step 4; otherwise, end.

[0068] Wherein, dTPV_t_diff_con_in is the preset speed step size control deviation.

[0069] Step 4: Adjust the speed step size △rpm_step of the variable frequency compressor to f(a,b,c,...)_2 as INT(TPV_rpm_step_change_corr_4*ROUND(ABS(dTPV_t_diff),2)+TPV_rpm_step_change_corr_5).

[0070] Where f(a,b,c,...)_2 is the preset minimum adjustment value of the speed step Δrpm_step, and TPV_rpm_step_change_corr_4 and TPV_rpm_step_change_corr_5 are the preset fourth step correction value and the preset fifth step correction value, respectively.

[0071] Step 5: Determine whether f(a,b,c,...)_2 is less than or equal to Δrpm_step_increase_min; if yes, proceed to step 6; if no, proceed to step 7.

[0072] Wherein, △rpm_step_increase_min is the preset minimum step size for speed change.

[0073] Step 6: Adjust f(a,b,c,...)_2 to △rpm_step_increase_min.

[0074] Step 7: Determine whether f(a,b,c,...)_2 is less than or equal to Δrpm_step_increase_max; if yes, proceed to step 8; if no, proceed to step 9.

[0075] Step 8: Use f(a,b,c,...)_2 at this time as the speed step size Δrpm_step of the variable frequency compressor.

[0076] Step 9: Use △rpm_step_increase_max as the speed step size △rpm_step of the variable frequency compressor.

[0077] It should be noted that each preset value in this embodiment can be set according to the actual speed step size control requirements, and is not limited here.

[0078] The variable frequency compressor speed step size control method provided in this embodiment controls the speed step size of the variable frequency compressor based on the determined current temperature and the temperature change rate at a preset time, the preset speed step size control deviation, and the preset step size correction value. This can improve the reliability of the speed step size control of the variable frequency compressor, thereby saving energy and improving energy-saving effect.

[0079] Example 3

[0080] Figure 6 This is a structural block diagram of a speed step control device for a variable frequency compressor provided in Embodiment 3 of the present invention. The variable frequency compressor is applied to an environmental testing equipment. The speed step control device includes: a temperature acquisition module 310, a rate determination module 320, and a step control module 330; wherein, the temperature acquisition module 310 is used to acquire the current temperature of the inner chamber of the environmental testing equipment and the temperature at a preset time before the current time; the rate determination module 320 is used to determine the rate of change of the current temperature and the temperature at the preset time based on the current temperature and the temperature at the preset time; the step control module 330 is used to control the speed step of the variable frequency compressor based on the rate of change, a preset speed step control deviation, and a preset step correction value.

[0081] Optionally, the rate determination module 320 includes: a difference determination unit and a rate determination unit; wherein, the difference determination unit is used to determine the difference between the current temperature and the temperature at the preset time, as well as the time difference between the current time and the preset time, based on the current temperature and the temperature at the preset time; the rate determination unit is used to use the ratio of the difference to the time difference as the rate of change.

[0082] In one embodiment, the preset step size correction value includes a preset fourth step size correction value and a preset fifth step size correction value; the step size control module 330 includes: a first adjustment unit and a second adjustment unit; wherein, the first adjustment unit is used to adjust the preset minimum adjustment value of the speed step size to the value obtained by multiplying the preset fourth step size correction value and the absolute value of the change rate (rounded to two decimal places) plus the preset fifth step size correction value if the rate of change is greater than or equal to the preset speed step size control deviation; the second adjustment unit is used to adjust the speed step size of the variable frequency compressor according to the preset minimum adjustment value of the speed step size.

[0083] Optionally, the second adjustment unit includes: a first adjustment subunit and a second adjustment subunit; wherein, the first adjustment subunit is used to adjust the preset minimum adjustment value to the preset minimum speed change step if the preset minimum adjustment value of the speed step is less than or equal to the preset minimum speed change step; the second adjustment subunit is used to use the preset minimum adjustment value at this time as the speed step of the variable frequency compressor if the preset minimum adjustment value of the speed step is less than or equal to the preset maximum speed change step.

[0084] Optionally, the second adjustment unit includes a third adjustment subunit and a fourth adjustment subunit; wherein, the third adjustment subunit is used to take the preset minimum adjustment value of the speed step as the speed step of the variable frequency compressor if the preset minimum adjustment value of the speed step is greater than the preset minimum speed change step and less than or equal to the preset maximum speed change step; the fourth adjustment subunit is used to take the preset maximum speed change step as the speed step of the variable frequency compressor if the preset minimum adjustment value of the speed step is greater than the preset maximum speed change step.

[0085] The speed step control device for the variable frequency compressor provided in this embodiment belongs to the same inventive concept as the speed step control method for the variable frequency compressor provided in any embodiment of the present invention, and has corresponding beneficial effects. For technical details not detailed in this embodiment, please refer to the speed step control method for the variable frequency compressor provided in any embodiment of the present invention.

[0086] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for controlling the speed step size of a variable frequency compressor, characterized in that, The variable frequency compressor is used in environmental testing equipment, and the speed step control method includes: Obtain the current temperature of the inner chamber of the environmental testing equipment and the temperature at a preset time before the current time; Based on the current temperature and the temperature at the preset time, determine the rate of change of the current temperature and the temperature at the preset time; The speed step of the variable frequency compressor is controlled according to the rate of change, the preset speed step control deviation, and the preset step correction value. The preset step size correction value includes a preset fourth step size correction value and a preset fifth step size correction value; The step of controlling the speed step of the variable frequency compressor based on the rate of change, the preset speed step control deviation, and the preset step correction value includes: If the rate of change is greater than or equal to the preset speed step size control deviation, then the preset minimum adjustment value of the speed step size is adjusted to the value obtained by multiplying the preset fourth step size correction value and the absolute value of the rate of change by two decimal places, plus the preset fifth step size correction value. The speed step size of the variable frequency compressor is adjusted according to the preset minimum adjustment value of the speed step size; The step of adjusting the speed step of the variable frequency compressor according to the preset minimum adjustment value of the speed step includes: If the preset minimum adjustment value of the speed step size is less than or equal to the preset minimum speed change step size, then the preset minimum adjustment value is adjusted to the preset minimum speed change step size. If the preset minimum adjustment value of the speed step is less than or equal to the preset maximum speed change step, then the preset minimum adjustment value at this time is taken as the speed step of the variable frequency compressor. The step of adjusting the speed step size of the variable frequency compressor according to the preset minimum adjustment value includes: If the preset minimum adjustment value of the speed step is greater than the preset minimum speed change step and less than or equal to the preset maximum speed change step, then the preset minimum adjustment value at this time is taken as the speed step of the variable frequency compressor. If the preset minimum adjustment value of the speed step is greater than the preset maximum value of the speed change step, then the preset maximum value of the speed change step is used as the speed step of the variable frequency compressor.

2. The speed step size control method according to claim 1, characterized in that, The step of determining the rate of change of the current temperature and the temperature at the preset time based on the current temperature and the temperature at the preset time includes: Based on the current temperature and the temperature at the preset time, determine the difference between the current temperature and the temperature at the preset time, as well as the time difference between the current time and the preset time; The ratio of the difference to the time difference is taken as the rate of change.

3. The speed step size control method according to claim 1, characterized in that, The preset minimum step size for speed change and the preset maximum step size for speed change are both values ​​corresponding to increasing the step size.

4. A speed step control device for a variable frequency compressor, characterized in that, The variable frequency compressor is used in environmental testing equipment, and the speed step control method as described in any one of claims 1-3 is applied to the variable frequency compressor, wherein the speed step control device includes: The temperature acquisition module is used to acquire the current temperature of the inner chamber of the environmental testing equipment and the temperature at a preset time before the current time. A rate determination module is used to determine the rate of change of the current temperature and the temperature at the preset time based on the current temperature and the temperature at the preset time. The step size control module is used to control the speed step size of the variable frequency compressor based on the rate of change, the preset speed step size control deviation, and the preset step size correction value.

5. The speed step size control device according to claim 4, characterized in that, The rate determination module includes: The difference determination unit is used to determine the difference between the current temperature and the temperature at the preset time, as well as the time difference between the current time and the preset time, based on the current temperature and the temperature at the preset time. A rate determination unit is used to take the ratio of the difference to the time difference as the rate of change.

6. A refrigeration system, characterized in that, The device includes a controller, a variable frequency compressor, a condenser, and an evaporator. The controller is electrically connected to the variable frequency compressor. The condenser is connected to the evaporator and the variable frequency compressor via a pipeline. The evaporator is connected to the variable frequency compressor via a pipeline. The speed step control device as described in any one of claims 4-5 is integrated into the controller.

7. The refrigeration system according to claim 6, characterized in that, It also includes an electronic expansion valve, which is disposed in the passage connecting the evaporator and the variable frequency compressor.

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