A control method and system for a variable frequency compressor

Abstract

This application provides a control method and system for a variable frequency compressor, comprising: acquiring the real-time temperature of each storage compartment of a refrigerator; acquiring the set target temperature of each storage compartment of the refrigerator; calculating the weighted temperature control error of the refrigerator based on the real-time temperature and the set target temperature of each storage compartment; acquiring the current operating frequency of the variable frequency compressor, and calculating the target operating frequency of the variable frequency compressor based on the weighted temperature control error of the refrigerator; if the target operating frequency of the variable frequency compressor is not less than the lower limit of the operating frequency of the variable frequency compressor under the current ambient temperature and not greater than the upper limit of the operating frequency of the variable frequency compressor under the current ambient temperature, then controlling the variable frequency compressor to operate at the target operating frequency until the variable frequency compressor stops; thereby solving the problem that the current variable frequency compressor control system cannot effectively detect temperature changes and cannot adjust the operating frequency of the variable frequency compressor in a timely manner, resulting in increased refrigerator energy consumption and reduced refrigerator performance.

Description

Technical Field

[0001] This application relates to the field of variable frequency compressor technology, and in particular to a control method and system for a variable frequency compressor. Background Technology

[0002] Currently, inverter compressors are widely used in refrigerators. These compressors typically have multiple operating frequencies, with different settings to accommodate varying ambient temperatures and cooling demands. In actual operation, the operating frequency of the inverter compressor is controlled based on the user-set temperature, the current ambient temperature, and the desired cooling performance.

[0003] The temperature of each compartment inside the refrigerator is typically detected and controlled using negative temperature coefficient sensors. When the temperature of a compartment rises to the set start-up temperature, the refrigeration system starts cooling that compartment; when the temperature of a compartment drops to the set stop-off temperature, the refrigeration system stops cooling that compartment. The control system for the inverter compressor adjusts its operating frequency based on the actual temperature values ​​received from the sensors. When the temperature sensor in a compartment detects a temperature significantly higher than the user-set temperature range, the control system increases the inverter compressor's operating frequency; when the temperature of any compartment has reached or fallen below the user-set temperature, the control system reduces the inverter compressor's operating frequency, thereby reducing energy consumption and noise.

[0004] Negative temperature coefficient (NTC) thermistors are typically used in refrigerators and other home appliances to create sensors. Their temperature accuracy is only 0.5–1°C. Refrigerators use small refrigeration systems, and their internal heating or cooling rates are generally slow. For example, in the freezer compartment, even after more than 15 minutes of cooling with a large amount of food stored, the temperature sensor may not drop more than 0.5°C. When the temperature rise or fall in the storage compartment is less than the accuracy of the temperature sensor, the control system cannot effectively detect the temperature change and cannot adjust the operating frequency of the inverter compressor in time. It can only handle situations with large temperature differences. Furthermore, once the inverter compressor's operating frequency increases, it maintains a high operating frequency for a prolonged period, resulting in increased energy consumption and significantly increased compressor noise, thus reducing the refrigerator's performance. Summary of the Invention

[0005] This application provides a control method and system for a variable frequency compressor to solve the technical problems of existing variable frequency compressor control systems being unable to effectively detect temperature changes, unable to adjust the operating frequency of the variable frequency compressor in a timely manner, only able to cope with situations with large temperature differences, and maintaining a high operating frequency for a long time once the operating frequency of the variable frequency compressor increases, which not only increases the energy consumption of the refrigerator, but also significantly increases the operating noise of the variable frequency compressor, and reduces the performance of the refrigerator.

[0006] This application provides a control method for a variable frequency compressor, including:

[0007] Obtain the real-time temperature of each storage compartment in the refrigerator;

[0008] Obtain the set target temperature for each storage compartment of the refrigerator;

[0009] Based on the real-time temperature of each storage compartment of the refrigerator and the set target temperature, the weighted temperature control error of the refrigerator is calculated.

[0010] Obtain the current operating frequency of the inverter compressor, and calculate the target operating frequency of the inverter compressor based on the weighted temperature control error of the refrigerator;

[0011] Obtain the ambient temperature of the refrigerator;

[0012] Based on the ambient temperature of the refrigerator, obtain the upper and lower limits of the operating frequency of the inverter compressor under the current ambient temperature;

[0013] The target operating frequency of the variable frequency compressor, the lower limit of the operating frequency of the variable frequency compressor under the current ambient temperature, and the upper limit of the operating frequency of the variable frequency compressor under the current ambient temperature are compared. If the target operating frequency of the variable frequency compressor is not less than the lower limit of the operating frequency of the variable frequency compressor under the current ambient temperature and not greater than the upper limit of the operating frequency of the variable frequency compressor under the current ambient temperature, then the variable frequency compressor is controlled to run at the target operating frequency until the variable frequency compressor stops. The stopping condition of the variable frequency compressor is that the real-time temperature of each storage compartment of the refrigerator is lower than or equal to the set target temperature; or the refrigerator receives a defrost command.

[0014] In some embodiments, after comparing the target operating frequency of the variable frequency compressor, the lower limit of the operating frequency of the variable frequency compressor under the current ambient temperature, and the upper limit of the operating frequency of the variable frequency compressor under the current ambient temperature, the method further includes:

[0015] If the target operating frequency of the variable frequency compressor is less than the lower limit of the compressor operating frequency under the current ambient temperature, then the variable frequency compressor is controlled to operate at the lower limit of the compressor operating frequency under the current ambient temperature until the variable frequency compressor stops.

[0016] If the target operating frequency of the variable frequency compressor is greater than the upper limit of the compressor operating frequency under the current ambient temperature, then the variable frequency compressor is controlled to operate at the upper limit of the compressor operating frequency under the current ambient temperature until the variable frequency compressor stops.

[0017] In some embodiments, prior to obtaining the real-time temperature of each storage compartment of the refrigerator, the following steps are included:

[0018] Obtain the status of the inverter compressor; if the inverter compressor is in the initial start-up state, obtain the ambient temperature of the refrigerator.

[0019] Based on the ambient temperature of the refrigerator, the lower limit of the operating frequency of the variable frequency compressor under the current ambient temperature is obtained, and the variable frequency compressor is controlled to operate at the lower limit of the compressor operating frequency under the current ambient temperature.

[0020] In some embodiments, the method further includes:

[0021] If the variable frequency compressor stops running, the operating frequency parameters of the variable frequency compressor before it stopped running are stored.

[0022] When the variable frequency compressor starts running, it is controlled to operate at the stored operating frequency parameters before the variable frequency compressor stopped running.

[0023] In some embodiments, obtaining the set target temperature for each storage compartment of the refrigerator includes:

[0024] Obtain the cooling start temperature and cooling stop temperature of each storage compartment in the refrigerator;

[0025] Based on the cooling start temperature and cooling stop temperature of each storage compartment of the refrigerator, the set target temperature of each storage compartment of the refrigerator is calculated.

[0026] In some embodiments, the weighted temperature control error of the refrigerator is:

[0027]

[0028] In the formula, T i (j) represents the real-time temperature of each storage compartment in the refrigerator, i represents the refrigerator storage compartment ID, ranging from 1 to n, n represents the total number of storage compartments in the refrigerator with independent temperature control, and j represents the inverter compressor start-up time sequence, starting from 1 and incrementing by 1 every Δt; T Ci The target temperature set for each storage compartment of the refrigerator; Z i This refers to the temperature error adjustment coefficient for each storage compartment of the refrigerator; where,

[0029] The second aspect of this application provides a control system for a variable frequency compressor, implementing the control method for a variable frequency compressor as described in any one of the first aspects, applied to a refrigerator, the refrigerator comprising: a variable frequency compressor disposed within the refrigerator body; at least one storage compartment; including:

[0030] An NTC temperature sensor is installed inside the storage chamber to obtain the temperature of the storage chamber.

[0031] An environmental sensor is installed outside the refrigerator body to obtain the ambient temperature of the refrigerator and, based on the ambient temperature of the refrigerator, to obtain the upper and lower limits of the operating frequency of the inverter compressor at the current ambient temperature.

[0032] The control module is communicatively connected to the NTC temperature sensor, the environmental sensor, and the variable frequency compressor. It compares the target operating frequency of the variable frequency compressor with the lower limit of the operating frequency under the current ambient temperature and the upper limit of the operating frequency under the current ambient temperature. If the target operating frequency of the variable frequency compressor is not less than the lower limit and not greater than the upper limit, the variable frequency compressor is controlled to operate at the target operating frequency until it stops. The shutdown condition for the variable frequency compressor is that the real-time temperature of each storage compartment of the refrigerator is lower than or equal to the set target temperature; or the refrigerator receives a defrost command.

[0033] In some embodiments, the control module is further configured to control the variable frequency compressor to operate at the lower limit of the compressor operating frequency under the current ambient temperature when the target operating frequency of the variable frequency compressor is less than the lower limit of the compressor operating frequency under the current ambient temperature, until the variable frequency compressor stops.

[0034] When the target operating frequency of the variable frequency compressor is greater than the upper limit of the compressor operating frequency under the current ambient temperature, the variable frequency compressor is controlled to operate at the upper limit of the compressor operating frequency under the current ambient temperature until the variable frequency compressor stops.

[0035] In some embodiments, the control module is further configured to acquire the status of the variable frequency compressor; if the variable frequency compressor is in the initial start-up state, it acquires the ambient temperature of the refrigerator obtained by the environmental sensor, and based on the ambient temperature of the refrigerator, acquires the lower limit parameter of the operating frequency of the variable frequency compressor under the current ambient temperature.

[0036] Based on the lower limit parameter of the variable frequency compressor operating frequency under the current ambient temperature, the variable frequency compressor is controlled to operate at the lower limit of the compressor operating frequency under the current ambient temperature.

[0037] In some embodiments, the control system of the variable frequency compressor further includes:

[0038] The storage module is communicatively connected to the control module and is used to store the operating frequency parameters of the variable frequency compressor before it stops running when the variable frequency compressor stops running; and to control the variable frequency compressor to run at the stored operating frequency parameters before it stops running when the variable frequency compressor starts running.

[0039] This application provides a control method and system for a variable frequency compressor, including: acquiring the real-time temperature of each storage compartment of a refrigerator; acquiring the set target temperature of each storage compartment of the refrigerator; calculating the weighted temperature control error of the refrigerator based on the real-time temperature and the set target temperature of each storage compartment; acquiring the current operating frequency of the variable frequency compressor, and calculating the target operating frequency of the variable frequency compressor based on the weighted temperature control error of the refrigerator; acquiring the ambient temperature of the refrigerator; acquiring the upper and lower limits of the operating frequency of the variable frequency compressor under the current ambient temperature based on the ambient temperature of the refrigerator; comparing the target operating frequency of the variable frequency compressor, the lower limit of the operating frequency of the variable frequency compressor under the current ambient temperature, and the upper limit of the operating frequency of the variable frequency compressor under the current ambient temperature; if the target operating frequency of the variable frequency compressor is not small... If the variable frequency compressor operates at the lower limit of the operating frequency under the current ambient temperature and is not greater than the upper limit of the operating frequency under the current ambient temperature, then the variable frequency compressor is controlled to operate at the target operating frequency until it stops. The shutdown condition of the variable frequency compressor is that the real-time temperature of each storage compartment of the refrigerator is lower than or equal to the set target temperature; or the refrigerator receives a defrost command. This addresses the problem that current variable frequency compressor control systems cannot effectively detect temperature changes and cannot adjust the operating frequency of the variable frequency compressor in a timely manner. They can only cope with situations with large temperature differences. Moreover, once the operating frequency of the variable frequency compressor increases, it will maintain a high operating frequency for a long time, which not only increases the energy consumption of the refrigerator but also significantly increases the operating noise of the variable frequency compressor, thus reducing the performance of the refrigerator. Attached Figure Description

[0040] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the control method for the variable frequency compressor in this application;

[0042] Figure 2 This is a schematic diagram of the control system of the variable frequency compressor in this application.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1-NTC temperature sensor; 2-Ambient sensor; 3-Control module; 4-Storage module. Detailed Implementation

[0045] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0046] Because some technologies fail to effectively detect temperature changes and adjust the compressor's operating frequency in a timely manner, they can only handle situations with large temperature differences. Furthermore, once the compressor's operating frequency increases, it maintains a high frequency for an extended period, leading to increased energy consumption and significantly higher operating noise, thus reducing the refrigerator's performance. To address this problem, this application provides a control method and system for a variable frequency compressor, which are described below:

[0047] Depend on Figure 1 As can be seen, this application provides a control method for a variable frequency compressor, including:

[0048] The real-time temperature of each storage compartment of the refrigerator is obtained using an NTC temperature sensor with an accuracy of 0.1℃ installed in each storage compartment. The temperature of each storage compartment is collected at the end of the j-th Δt time period. Before obtaining the real-time temperature of each storage compartment, the following steps are taken: The status of the inverter compressor is obtained; if the inverter compressor is in its initial startup state, the ambient temperature of the refrigerator is obtained; based on the ambient temperature, the lower limit of the inverter compressor's operating frequency under the current ambient temperature is obtained, and the inverter compressor is controlled to operate at the lower limit of the compressor's operating frequency under the current ambient temperature. If the refrigerator is in its initial startup state, the ambient temperature of the refrigerator is first obtained using an environmental sensor, and the lower limit of the inverter compressor's operating frequency under the current ambient temperature is also obtained, causing the refrigerator to operate at the lower limit of the inverter compressor's operating frequency under the current ambient temperature. After running for two Δt time periods, the inverter compressor's operating frequency is recalculated, and the calculated inverter compressor operating frequency is compared with the upper and lower limits of the inverter compressor's operating frequency under the current ambient temperature to determine the target operating frequency and control the inverter compressor to operate.

[0049] Obtain the set target temperature for each storage compartment of the refrigerator; obtaining the set target temperature for each storage compartment of the refrigerator includes: obtaining the cooling start temperature T of each storage compartment of the refrigerator. i_on and the cooling stop temperature T i_off The cooling start temperature is the temperature at which the refrigerator needs to start cooling when the temperature of the storage compartment exceeds or reaches the cooling start temperature; the cooling start setpoint is the temperature at which the refrigerator stops cooling when the temperature of the storage compartment falls below or reaches the cooling stop temperature; the cooling stop setpoint is the temperature at which the refrigerator stops cooling based on the cooling start temperature and cooling stop temperature of each storage compartment. The set target temperature of each storage compartment is: T ci =(T i_on +T i_off ) / 2; Based on the real-time temperature of each storage compartment of the refrigerator and the set target temperature, calculate the weighted temperature control error of the refrigerator; The weighted temperature control error of the refrigerator is:

[0050]

[0051] In the formula, T i (j) represents the real-time temperature of each storage compartment in the refrigerator, i represents the refrigerator storage compartment ID, ranging from 1 to n, n represents the total number of storage compartments in the refrigerator with independent temperature control, and j represents the inverter compressor start-up time sequence, starting from 1 and incrementing by 1 every Δt; T Ci The target temperature set for each storage compartment of the refrigerator; Z i This refers to the temperature error adjustment coefficient for each storage compartment of the refrigerator;

[0052] in,

[0053] Obtain the current operating frequency of the inverter compressor. Based on the weighted temperature control error of the refrigerator, calculate the target operating frequency of the inverter compressor. When the refrigerator reaches the end of the j-th Δt time interval, calculate the compressor operating frequency for the next Δt time interval; S(j+1)=S(j)+K p ·[e(j)-e(j-1)]+K i ·e(j)+K d ·[e(j)-2·e(j-1)+e(j-2)] is the target operating frequency of the variable frequency compressor; where K p K is the proportional adjustment factor. i K is the integral adjustment factor. dThe above adjustment coefficient is a differential adjustment coefficient, which is adjusted by the refrigerator designer. By adjusting the above adjustment coefficient, the variable frequency compressor can more accurately regulate the cooling temperature of the refrigerator; S(j) is the operating frequency of the variable frequency compressor in a certain time period Δt. The calculation result is rounded to an integer, where S(j) is the operating frequency of the variable frequency compressor in the previous time period Δt. Based on the adjustment process when the refrigerator is first started, the operating frequency of the variable frequency compressor in the previous time period Δt is a known quantity.

[0054] Obtain the ambient temperature T of the refrigerator amb The ambient temperature of the refrigerator is obtained through environmental sensors; based on the ambient temperature of the refrigerator, the upper limit S of the operating frequency S of the inverter compressor under the current ambient temperature is obtained. H and lower limit S L The system compares the target operating frequency of the inverter compressor, the lower limit of the inverter compressor's operating frequency under the current ambient temperature, and the upper limit of the inverter compressor's operating frequency under the current ambient temperature. If the target operating frequency of the inverter compressor is not less than the lower limit of the inverter compressor's operating frequency under the current ambient temperature and not greater than the upper limit of the inverter compressor's operating frequency under the current ambient temperature, then the inverter compressor is controlled to operate at the target operating frequency until it stops. The shutdown condition for the inverter compressor is that the real-time temperature of each storage compartment of the refrigerator is lower than or equal to the set target temperature; or the refrigerator receives a defrost command. That is, S L (T amb )≤S(j+1)≤S H (T amb During the next Δt time period, the variable frequency compressor operates at S(j+1); the refrigerator obtains the defrost command when the refrigerator's defrost control program determines that the refrigerator needs to defrost the finned evaporator inside the refrigerator, sends the defrost command to the defrost element inside the refrigerator, the defrost element starts, the variable frequency compressor stops, and after the frost inside the refrigerator is removed, the variable frequency compressor starts and operates at the operating frequency parameters before stopping.

[0055] After comparing the target operating frequency of the variable frequency compressor, the lower limit of the operating frequency of the variable frequency compressor under the current ambient temperature, and the upper limit of the operating frequency of the variable frequency compressor under the current ambient temperature, the method further includes:

[0056] If the target operating frequency of the variable frequency compressor is less than the lower limit of the compressor operating frequency under the current ambient temperature, then the variable frequency compressor is controlled to operate at the lower limit of the compressor operating frequency under the current ambient temperature until the variable frequency compressor stops; that is, S(j+1) < S L (T amb Then, in the next Δt time period, the variable frequency compressor will operate at S... L (T amb) Operation;

[0057] If the target operating frequency of the variable frequency compressor is greater than the upper limit of the compressor operating frequency under the current ambient temperature, then the variable frequency compressor is controlled to operate at the upper limit of the compressor operating frequency under the current ambient temperature until the variable frequency compressor stops; that is, S(j+1)>S H (T amb If the variable frequency compressor operates at S during the next Δt time interval, then... H (T amb (Operation)

[0058] The method further includes: if the variable frequency compressor stops running, storing the operating frequency parameters of the variable frequency compressor before it stops running; if the variable frequency compressor stops running due to a power outage or other emergency, recording and storing the operating frequency parameters of the variable frequency compressor before it stops running; and when the variable frequency compressor starts running, controlling the variable frequency compressor to run at the stored operating frequency parameters of the variable frequency compressor before it stops running.

[0059] It is understood that an embodiment of the variable frequency compressor control method provided in this application is as follows: When the refrigerator is in the initial start-up state, the ambient temperature of the refrigerator is obtained; based on the ambient temperature of the refrigerator, the lower limit of the variable frequency compressor operating frequency under the current ambient temperature is obtained, and the variable frequency compressor is controlled to operate at the lower limit of the compressor operating frequency under the current ambient temperature. After running for two Δt times, the real-time temperature of each storage compartment of the refrigerator and the set target temperature of each storage compartment are obtained; based on the real-time temperature and set target temperature of each storage compartment of the refrigerator, the weighted temperature control error of the refrigerator is calculated; the current operating frequency of the variable frequency compressor is obtained, and the target operating frequency of the variable frequency compressor is calculated based on the weighted temperature control error of the refrigerator; the ambient temperature of the refrigerator is obtained; based on the ambient temperature of the refrigerator, the upper and lower limits of the variable frequency compressor operating frequency under the current ambient temperature are obtained; and the variable frequency compressor is controlled to operate at the lower limit of the compressor operating frequency under the current ambient temperature. The compressor's target operating frequency, the lower limit of the inverter compressor's operating frequency under the current ambient temperature, and the upper limit of the inverter compressor's operating frequency under the current ambient temperature are compared. If the target operating frequency of the inverter compressor is not less than the lower limit and not greater than the upper limit of the inverter compressor's operating frequency under the current ambient temperature, the inverter compressor is controlled to operate at the target operating frequency. If the target operating frequency of the inverter compressor is less than the lower limit of the compressor's operating frequency under the current ambient temperature, the inverter compressor is controlled to operate at the lower limit of the compressor's operating frequency under the current ambient temperature. If the target operating frequency of the inverter compressor is greater than the upper limit of the compressor's operating frequency under the current ambient temperature, the inverter compressor is controlled to operate at the upper limit of the compressor's operating frequency under the current ambient temperature until the inverter compressor stops. The compressor's operating frequency needs to be recalculated every Δt time interval, according to the above operating frequency control standard, so that the refrigerator can always maintain a low operating frequency, reducing energy consumption and noise.

[0060] The variable frequency compressor control method provided in this application has the following beneficial effects: it improves the temperature control accuracy of each storage compartment of the refrigerator from 0.5-1℃ to 0.1℃, enabling the refrigerator to achieve more precise temperature control; it can respond more sensitively to changes in heat load and air temperature in each storage compartment of the refrigerator, thereby adjusting the operating frequency of the variable frequency compressor and quickly restoring the temperature of each storage compartment to the target set temperature, significantly reducing the disturbance to the internal storage temperature of the refrigerator caused by user use; it enables the operating frequency of the variable frequency compressor to more accurately adapt to the environment and internal load of the refrigerator. When the temperature of each storage compartment reaches the user-set temperature, the operating frequency of the variable frequency compressor will quickly decrease to the adaptive operating frequency, thereby reducing energy consumption and operating noise.

[0061] Depend on Figure 2As can be seen, the second aspect of this application provides a control system for a variable frequency compressor, implementing a control method for a variable frequency compressor as described in any of the above embodiments, applied to a refrigerator. The refrigerator includes: a variable frequency compressor disposed within the refrigerator body; at least one storage compartment; including: an NTC temperature sensor 1 disposed within the storage compartment for acquiring the temperature of the storage compartment; an environmental sensor 2 disposed outside the refrigerator body for acquiring the ambient temperature of the refrigerator, and based on the ambient temperature of the refrigerator, acquiring the upper and lower limits of the operating frequency of the variable frequency compressor under the current ambient temperature; and a control module 3, the control module 3 being connected to the NTC compressor... Temperature sensor 1, environmental sensor 2, and the variable frequency compressor are communicatively connected. The system compares the target operating frequency of the variable frequency compressor with the lower limit of its operating frequency under the current ambient temperature and the upper limit of its operating frequency under the same ambient temperature. If the target operating frequency of the variable frequency compressor is not less than the lower limit and not greater than the upper limit, the system controls the variable frequency compressor to operate at the target operating frequency until it stops. The stopping condition for the variable frequency compressor is that the real-time temperature of each storage compartment of the refrigerator is lower than or equal to the set target temperature, or the refrigerator receives a defrost command. The effects of each part of the system when executing the above method can be found in the above method embodiments, and will not be repeated here.

[0062] In this embodiment, the control module 3 is further configured to control the variable frequency compressor to operate at the lower limit of the compressor operating frequency under the current ambient temperature until the variable frequency compressor stops when the target operating frequency of the variable frequency compressor is less than the lower limit of the compressor operating frequency under the current ambient temperature; and to control the variable frequency compressor to operate at the upper limit of the compressor operating frequency under the current ambient temperature until the variable frequency compressor stops when the target operating frequency of the variable frequency compressor is greater than the upper limit of the compressor operating frequency under the current ambient temperature. The effects of each part of the system when executing the above method can be found in the above method embodiment, and will not be repeated here.

[0063] In this embodiment, the control module 3 is further configured to acquire the status of the variable frequency compressor. If the variable frequency compressor is in its initial startup state, it acquires the ambient temperature of the refrigerator obtained by the environmental sensor 2. Based on the ambient temperature of the refrigerator, it acquires the lower limit parameter of the variable frequency compressor's operating frequency under the current ambient temperature. Based on the lower limit parameter of the variable frequency compressor's operating frequency under the current ambient temperature, it controls the variable frequency compressor to operate at the lower limit of the compressor's operating frequency under the current ambient temperature. The effects of each part of the above system when executing the above method can be found in the above method embodiment, and will not be repeated here.

[0064] Depend on Figure 2 As can be seen, the control system for the variable frequency compressor further includes: a storage module 4, which is communicatively connected to the control module 3. The storage module 4 stores the operating frequency parameters of the variable frequency compressor before it stops running, and controls the variable frequency compressor to operate at the stored operating frequency parameters before it stops running, when the variable frequency compressor starts running. The effects of each part of the system when executing the above method can be found in the above method embodiments, and will not be repeated here.

[0065] This application provides a control method and system for a variable frequency compressor, embodiment one:

[0066] If this solution is used for a single-temperature freezer with only one storage compartment, it employs a single NTC temperature sensor with an accuracy of 0.1℃. The refrigeration system uses an inverter compressor, and the main control board integrates user-display temperature adjustment, inverter, and ambient temperature sensor modules. Since the refrigerator has only one storage compartment, n=1, K p K i and K d The value is an integer, determined by the manufacturer based on the shortest time it takes for a single-temperature freezer to return to constant low speed operation after being subjected to a heat load. The value is generally between 10 and 2000. The operating frequency judgment cycle of the variable frequency compressor is 5 to 20 minutes.

[0067] Example 2:

[0068] If this solution is used for a frost-free refrigerator, the refrigerator has at least one refrigerator compartment and one freezer compartment. Each compartment uses an NTC temperature sensor with an accuracy of 0.1℃. The refrigeration system uses an inverter compressor and has a finned evaporator. When the evaporator is working, the refrigeration fan blows the cooled airflow from the evaporator into each compartment for cooling. The flow rate is controlled by the air duct and damper. The inverter and display control board can be connected independently to the refrigerator's main control board or integrated into it. If the refrigerator has two or more independent compartments, then n≥2. Generally, the freezer compartment Z1≥0.5, the refrigerator compartment Z2≥0.2, and the values ​​for other compartments must satisfy the following formula: K p K i and K d The value is an integer, determined by the manufacturer based on the shortest time it takes for each compartment of the refrigerator to return to constant low speed operation after being subjected to a heat load. The value is generally between 10 and 2000. The operating frequency judgment cycle of the inverter compressor is 5 to 20 minutes.

[0069] Example 3:

[0070] If this solution is used for a frost-free refrigerator, the refrigerator has at least one refrigerator compartment and one freezer compartment. Each compartment uses an NTC temperature sensor with an accuracy of 0.1℃. The refrigeration system uses an inverter compressor, has two or more evaporators and the same number of capillary tubes. Electric valves (or solenoid valves) control the flow of refrigerant through different capillary tubes and evaporators, thereby achieving cooling and temperature control for each compartment. The inverter and display control board can be connected independently to the refrigerator's main control board or integrated into it. If the refrigerator has two or more independent compartments, then n≥2. Generally, the freezer compartment Z1≥0.5, the refrigerator compartment Z2≥0.2, and the values ​​for other compartments must satisfy the following formula: K p K i and K d The value is an integer, determined by the manufacturer based on the shortest time it takes for each storage compartment of the refrigerator to return to constant low speed operation after being subjected to a heat load. The value is generally between 10 and 2000, and the compressor operation frequency judgment cycle is 5 to 20 minutes.

[0071] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A control method of a variable frequency compressor, characterized by, The method comprises: acquiring real-time temperatures of each storage compartment of the refrigerator; acquiring set target temperatures of each storage compartment of the refrigerator; calculating a weighted temperature control error of the refrigerator based on the real-time temperatures and the set target temperatures of each storage compartment of the refrigerator; acquiring a current operating frequency of the variable-frequency compressor, and calculating a target operating frequency of the variable-frequency compressor based on the weighted temperature control error of the refrigerator; acquiring an ambient temperature of the refrigerator; acquiring an upper limit and a lower limit of the operating frequency of the variable-frequency compressor at the current ambient temperature based on the ambient temperature of the refrigerator; comparing the target operating frequency of the variable-frequency compressor, the lower limit of the operating frequency of the variable-frequency compressor at the current ambient temperature, and the upper limit of the operating frequency of the variable-frequency compressor at the current ambient temperature, and if the target operating frequency of the variable-frequency compressor is not less than the lower limit of the operating frequency of the variable-frequency compressor at the current ambient temperature and not greater than the upper limit of the operating frequency of the variable-frequency compressor at the current ambient temperature, controlling the variable-frequency compressor to operate at the target operating frequency until the variable-frequency compressor stops; or the refrigerator acquires a defrosting instruction; after the comparison of the target operating frequency of the variable-frequency compressor, the lower limit of the operating frequency of the variable-frequency compressor at the current ambient temperature, and the upper limit of the operating frequency of the variable-frequency compressor at the current ambient temperature, the method further comprises: if the target operating frequency of the variable-frequency compressor is less than the lower limit of the operating frequency of the variable-frequency compressor at the current ambient temperature, controlling the variable-frequency compressor to operate at the lower limit of the operating frequency of the variable-frequency compressor at the current ambient temperature until the variable-frequency compressor stops; if the target operating frequency of the variable-frequency compressor is greater than the upper limit of the operating frequency of the variable-frequency compressor at the current ambient temperature, controlling the variable-frequency compressor to operate at the upper limit of the operating frequency of the variable-frequency compressor at the current ambient temperature until the variable-frequency compressor stops; the weighted temperature control error of the refrigerator is: In the formula, T i (j) is the real-time temperature of each storage compartment of the refrigerator, i is the refrigerator storage compartment ID, and n is the total number of storage compartments of the refrigerator with independent temperature control, j is the variable frequency compressor start time period sequence, starting from 1 and increasing by 1 every Δt; T Ci is the set target temperature of each storage compartment of the refrigerator; Z i is the temperature error adjustment coefficient of each storage compartment of the refrigerator; wherein, 2. The control method of a variable frequency compressor according to claim 1, wherein, before the acquisition of the real-time temperatures of each storage compartment of the refrigerator, the method comprises: acquiring a state of the variable-frequency compressor, and if the variable-frequency compressor is in a first start state, acquiring an ambient temperature of the refrigerator; based on the ambient temperature of the refrigerator, acquiring a lower limit of the operating frequency of the variable-frequency compressor at the current ambient temperature, and controlling the variable-frequency compressor to operate at the lower limit of the operating frequency of the variable-frequency compressor at the current ambient temperature.

3. The control method of a variable frequency compressor according to claim 1, wherein, The method further comprises: if the variable-frequency compressor stops operating, storing an operating frequency parameter of the variable-frequency compressor before the variable-frequency compressor stops operating; when the variable-frequency compressor starts operating, controlling the variable-frequency compressor to operate at the stored operating frequency parameter of the variable-frequency compressor before the variable-frequency compressor stops operating.

4. The control method of a variable frequency compressor according to claim 1, wherein, The acquisition of the set target temperatures of each storage compartment of the refrigerator comprises: acquiring refrigeration start temperatures and refrigeration stop temperatures of each storage compartment of the refrigerator; calculating the set target temperatures of each storage compartment of the refrigerator based on the refrigeration start temperatures and the refrigeration stop temperatures of each storage compartment of the refrigerator.

5. A control system of a variable frequency compressor, implementing the control method of any one of claims 1 to 4, applied to a refrigerator, the refrigerator comprising: The variable-frequency compressor is arranged in the refrigerator body; at least one storage compartment; characterized in that, comprising: An NTC temperature sensor (1) is arranged in the storage compartment to obtain the temperature of the storage compartment; An environment sensor (2) is arranged outside the refrigerator body to obtain the ambient temperature of the refrigerator, and based on the ambient temperature of the refrigerator, the upper and lower limits of the operating frequency of the variable frequency compressor at the current ambient temperature are obtained; A control module (3) is in communication connection with the NTC temperature sensor (1), the environment sensor (2) and the variable frequency compressor, and is used to compare the target operating frequency of the variable frequency compressor, the lower limit of the operating frequency of the variable frequency compressor at the current ambient temperature and the upper limit of the operating frequency of the variable frequency compressor at the current ambient temperature. If the target operating frequency of the variable frequency compressor is not less than the lower limit of the operating frequency of the variable frequency compressor at the current ambient temperature and not greater than the upper limit of the operating frequency of the variable frequency compressor at the current ambient temperature, the variable frequency compressor is controlled to operate at the target operating frequency until the variable frequency compressor stops; the stop condition of the variable frequency compressor is that the real-time temperature of each storage compartment of the refrigerator is lower than or equal to the set target temperature; or the refrigerator obtains defrosting instruction.

6. The control system of a variable frequency compressor according to claim 5, wherein, The control module (3) is also used to control the variable frequency compressor to operate at the lower limit of the operating frequency of the compressor at the current ambient temperature when the target operating frequency of the variable frequency compressor is less than the lower limit of the operating frequency of the compressor at the current ambient temperature, until the variable frequency compressor stops; When the target operating frequency of the variable frequency compressor is greater than the upper limit of the operating frequency of the compressor at the current ambient temperature, the variable frequency compressor is controlled to operate at the upper limit of the operating frequency of the compressor at the current ambient temperature until the variable frequency compressor stops.

7. The control system of a variable frequency compressor according to claim 5, wherein, The control module (3) is also used to obtain the state of the variable frequency compressor, and if the variable frequency compressor is in the initial start state, the ambient temperature of the refrigerator obtained by the environment sensor (2) is obtained, and based on the ambient temperature of the refrigerator, the lower limit parameter of the operating frequency of the variable frequency compressor at the current ambient temperature is obtained, Based on the lower limit parameter of the operating frequency of the variable frequency compressor at the current ambient temperature, the variable frequency compressor is controlled to operate at the lower limit of the operating frequency of the compressor at the current ambient temperature.

8. The control system of a variable frequency compressor according to claim 5, wherein, Further comprising: A storage module (4) is in communication connection with the control module (3), and is used to store the operating frequency parameter before the variable frequency compressor stops operating when the variable frequency compressor stops operating; when the variable frequency compressor starts operating, the variable frequency compressor is controlled to operate at the stored operating frequency parameter before the variable frequency compressor stops operating.

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