Refrigerator and control method therefor

Abstract

Provided are a refrigerator and a control method therefor. The refrigerator at least comprises a variable frequency controller (8), and the variable frequency controller (8) is used for: controlling a compressor (1) to operate to a target rotational speed level; and when the compressor (1) is operating at the target rotational speed level, adjusting the carrier frequency of the variable frequency controller (8) to the next carrier frequency level step by step until the current energy consumption of the variable frequency controller (8) is greater than or equal to the previous energy consumption of the variable frequency controller (8), stopping step-by-step adjustment, and adjusting the carrier frequency of the variable frequency controller (8) to the previous carrier frequency level.

Description

Refrigerator and control method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202410254090.0, filed on March 6, 2024, entitled “A refrigerator and its compressor speed control method”; and priority to Chinese patent application number 202410444352.X, filed on April 12, 2024, entitled “A refrigerator and its control method”; and priority to Chinese patent application number 202411116981.6, filed on August 14, 2024, entitled “A refrigerator and its control method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of electrical equipment, and in particular to a refrigerator and a control method thereof. Background Art

[0004] Refrigerators have gradually become an indispensable household appliance in people's lives. With the improvement of living standards and the development of technology, people's requirements for refrigerators are getting higher and higher, such as energy saving, heat dissipation, and compatibility with home circuits. Summary of the Invention

[0005] The present application provides a refrigerator and a control method thereof to meet user requirements for refrigerator performance.

[0006] In a first aspect, some embodiments of the present application provide a refrigerator, comprising:

[0007] A box body, having at least one storage compartment therein;

[0008] A box door is provided at the opening of the storage chamber;

[0009] A compressor is arranged in the box;

[0010] The variable frequency controller is configured as:

[0011] Controlling the compressor to run to a target speed gear;

[0012] When the compressor is at the target speed gear, gradually adjust the carrier frequency of the frequency conversion controller to the next carrier frequency gear until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, stop the gradual adjustment, and adjust the carrier frequency of the frequency conversion controller to the previous carrier frequency gear;

[0013] The current energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the current carrier frequency gear; the previous energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the previous carrier frequency gear.

[0014] In a second aspect, some embodiments of the present application further provide a method for controlling a refrigerator, the refrigerator comprising at least a compressor and a frequency conversion controller, the method comprising:

[0015] Controlling the compressor to run to a target speed gear;

[0016] When the compressor is at the target speed gear, gradually adjust the carrier frequency of the frequency conversion controller to the next carrier frequency gear until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, stop the gradual adjustment, and adjust the carrier frequency of the frequency conversion controller to the previous carrier frequency gear;

[0017] The current energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the current carrier frequency gear; the previous energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the previous carrier frequency gear.

[0018] The first and second aspects of the present application provide a refrigerator and a control method thereof, which realizes variable carrier frequency control, improves energy-saving effects (i.e., reduces energy consumption), and meets energy-saving requirements by gradually adjusting the carrier frequency of the frequency conversion controller to the next carrier frequency gear while controlling the compressor to be at a target speed gear, until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, stops the gradual adjustment, and adjusts the carrier frequency of the frequency conversion controller to the previous carrier frequency gear.

[0019] In a third aspect, some embodiments of the present application further provide a refrigerator, comprising:

[0020] a box body, in which at least one storage chamber is formed;

[0021] A box door is provided at the opening of the storage chamber;

[0022] A compressor is arranged in the box;

[0023] A frequency conversion controller is provided in the housing. The frequency conversion controller is provided with a PID controller. The frequency conversion controller is configured as follows:

[0024] Obtaining electrical parameters of the motor in the frequency conversion controller, and calculating output power based on the electrical parameters and preset frequency conversion characteristic parameters;

[0025] When the output power does not match the preset target power, the output power is used as the input of the PID controller, and a reference speed is output to the compressor through PID regulation, so that the compressor operates at the reference speed.

[0026] In a fourth aspect, some embodiments of the present application further provide a refrigerator control method, which is applied to a refrigerator, wherein the refrigerator includes a frequency conversion controller, a compressor, and a PID controller, and the method includes:

[0027] Obtaining electrical parameters of the motor in the frequency conversion controller, and calculating the output power based on the electrical parameters and preset frequency conversion characteristic parameters;

[0028] When the output power does not match the preset target power, the output power is used as the input of the PID controller, and a reference speed is output to the compressor through PID regulation, so that the compressor operates at the reference speed.

[0029] The refrigerator and the compressor speed control method disclosed in the third and fourth aspects add a PID control link in the frequency conversion controller. Without adding heat dissipation devices, the PID control method is used to realize the heat dissipation process of the frequency conversion controller. The control accuracy is high and the deviation is small, which can avoid the phenomenon of ultra-high temperature failure of the power devices on the frequency conversion controller.

[0030] In a fifth aspect, some embodiments of the present application further provide a refrigerator, comprising:

[0031] a box body, in which at least one storage chamber is formed;

[0032] A box door is provided at the opening of the storage chamber;

[0033] A compressor is arranged in the box;

[0034] a sampling circuit, disposed in the box, configured to sample leakage current at a power input terminal of the refrigerator;

[0035] A frequency conversion controller is provided in the box, and the frequency conversion controller is configured as follows:

[0036] Obtaining a leakage current at a power input terminal of the refrigerator collected by the sampling circuit;

[0037] When the value of the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold;

[0038] The carrier frequency increase amount of the frequency conversion controller is determined according to the current difference, and the carrier frequency of the frequency conversion controller is adjusted according to the carrier frequency increase amount.

[0039] In a sixth aspect, the present application further provides a refrigerator control method, which is applied to a refrigerator, wherein the refrigerator includes a sampling circuit configured to sample a leakage current at a power input terminal of the refrigerator, the method comprising:

[0040] Obtaining a leakage current at a power input terminal of the refrigerator collected by the sampling circuit;

[0041] When the value of the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold;

[0042] A carrier frequency increase amount of a frequency conversion controller in the refrigerator is determined according to the current difference, and the carrier frequency of the frequency conversion controller is adjusted according to the carrier frequency increase amount.

[0043] The refrigerator and refrigerator control method provided in the fifth and sixth aspects can increase the carrier frequency (switching power device frequency) of the frequency conversion controller, effectively adjust the output carrier frequency of the frequency conversion controller to achieve compatibility with GFCI, increase the PWM carrier frequency of the frequency conversion controller, and effectively curb tripping.

[0044] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0046] FIG1 is a schematic structural diagram of a refrigerator according to some embodiments;

[0047] FIG2 is a schematic structural diagram of a refrigeration system in a refrigerator according to some embodiments;

[0048] FIG3 is a schematic structural diagram of circuit connections of a refrigerator according to some embodiments;

[0049] FIG4 is a flowchart of a frequency conversion controller according to some embodiments;

[0050] FIG5 is another schematic structural diagram of circuit connections of a refrigerator according to some embodiments;

[0051] FIG6 is another working flow diagram of a variable frequency controller according to some embodiments;

[0052] FIG7 is a schematic structural diagram of a current sampling device according to some embodiments;

[0053] FIG8 is a schematic structural diagram of a voltage sampling device according to some embodiments;

[0054] FIG9 is another schematic structural diagram of a voltage sampling device according to some embodiments;

[0055] FIG10 is a flow chart of a method for controlling a refrigerator according to some embodiments;

[0056] FIG11 is a schematic diagram of the external structure of a refrigerator according to some embodiments;

[0057] FIG12 is a schematic diagram of the internal structure of a refrigerator according to some embodiments;

[0058] FIG13 is a schematic structural diagram of a refrigeration system in a refrigerator according to some embodiments;

[0059] FIG14 is a schematic structural diagram of a compressor cabin according to some embodiments;

[0060] FIG15 is a schematic diagram showing the connection between a variable frequency controller and a compressor according to some embodiments;

[0061] FIG16 is another working flow diagram of a frequency conversion controller in a refrigerator according to some embodiments;

[0062] FIG17 is a schematic diagram of a PID control link according to some embodiments;

[0063] FIG18 is another working flow diagram of a frequency conversion controller in a refrigerator according to some embodiments;

[0064] FIG19 is a schematic diagram of an FOC framework of a motor in a variable frequency controller according to some embodiments;

[0065] FIG20 is a flow chart of a method for controlling a compressor speed of a refrigerator according to some embodiments;

[0066] FIG21 is another working flow diagram of a frequency conversion controller in a refrigerator according to some embodiments;

[0067] FIG22 is another working flow diagram of a frequency conversion controller in a refrigerator according to some embodiments;

[0068] FIG23 is a schematic diagram showing connections among a sampling circuit, a variable frequency controller, and a compressor according to some embodiments;

[0069] FIG24 is a circuit diagram of a sampling circuit according to some embodiments;

[0070] FIG25 is a flow chart of a refrigerator control method according to some embodiments. DETAILED DESCRIPTION

[0071] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0072] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0073] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0074] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply 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 a limitation on this application.

[0075] Refrigerators are essential household appliances. To overcome the noise and poor freshness-keeping issues of fixed-frequency refrigerators, inverter refrigerators have emerged. However, inverter refrigerators operate at a single carrier frequency and cannot effectively meet energy-saving requirements.

[0076] Based on this, some embodiments of the present application provide a refrigerator.

[0077] FIG1 is a schematic structural diagram of a refrigerator provided according to some embodiments of the present application. Referring to FIG1 , the refrigerator has an approximately rectangular parallelepiped shape and includes a housing 100 defining a storage space and a door 200 provided at the opening of the housing 100. The door 200 includes a door outer shell and a door liner. When the door 200 is closed, the door outer shell is located on the outside of the housing 100 and the door liner is located on the inside of the housing 100. The door 200 also includes an upper end cover and a lower end cover, as well as an insulating layer located between the door outer shell, the door liner, the upper end cover, and the lower end cover. Typically, the insulating layer is filled with foam. The housing 100 is provided with a chamber, wherein the chamber includes a component storage chamber for placing components in the refrigerator, such as a compressor compartment, etc., and also includes a storage space for storing food, etc. The compressor can provide power for the refrigeration cycle of the refrigerator. The storage space can be divided into at least one storage room. Depending on the purpose, the storage room can be configured as a refrigerator, a freezer, a temperature-changing room (also known as a fresh-keeping room). It can also include a vacuum drawer, a moisturizing drawer, etc. Each storage room corresponds to one or more doors. For example, in Figure 1, the upper storage room is provided with two doors. The door can be pivotally arranged at the opening of the box body, or it can be opened in a drawer-like manner to achieve drawer-type storage. In some embodiments, the door of the refrigerator is also provided with a display screen, which is configured to display prompt information and receive user touch operations.

[0078] Referring to FIG. 2 , FIG. 2 is a schematic diagram of the structure of a refrigerator refrigeration system according to some embodiments of the present application. The refrigeration system includes a compressor 1, a condenser 2, an anti-condensation tube 3, a drying filter 4, a capillary tube 5, an evaporator 6, and a gas-liquid separator 7. The operating process of the refrigeration system includes a compression process, a condensation process, a throttling process, and an evaporation process.

[0079] The compression process is as follows: When the refrigerator is plugged in and the thermostat contacts are connected, compressor 1 begins operating. Low-temperature, low-pressure refrigerant is drawn into compressor 1, compressed within the compressor cylinder into high-temperature, high-pressure superheated gas, and then discharged into condenser 2. The condensation process is as follows: The high-temperature, high-pressure refrigerant gas dissipates heat through condenser 2, gradually cooling to a saturated vapor at room temperature and high pressure. It then cools further to a saturated liquid, where the temperature stops falling. This temperature is called the condensation temperature. The refrigerant pressure remains virtually unchanged throughout the condensation process. The throttling process is as follows: The condensed saturated refrigerant liquid passes through filter drier 4 to remove moisture and impurities, then flows into capillary tube 5, where it undergoes throttling and pressure reduction, turning the refrigerant into a wet vapor at room temperature and low pressure. The evaporation process is as follows: the wet steam at room temperature and low pressure begins to absorb heat and vaporize in the evaporator 6, which not only reduces the temperature of the evaporator 6 and its surroundings, but also turns the refrigerant into a low-temperature, low-pressure gas. The refrigerant coming out of the evaporator 6 passes through the gas-liquid separator 7 and returns to the compressor 1 again. The above process is repeated to transfer the heat in the refrigerator to the air outside the box, thereby achieving the purpose of refrigeration.

[0080] The fan allows air to continuously enter the fins of the evaporator 6 for heat exchange, and at the same time sends the air that has cooled after the evaporator 6 releases heat to the refrigeration room and the freezer through the air duct. In this way, the air in the storage room continuously circulates to achieve the purpose of lowering the temperature.

[0081] 3 , the refrigerator provided in some embodiments of the present application further includes a frequency conversion controller 8 connected to the compressor 1 and configured as follows:

[0082] Controlling the compressor 1 to run to a target speed gear;

[0083] When the compressor 1 is at the target speed gear, gradually adjust the carrier frequency of the frequency conversion controller 8 to the next carrier frequency gear until the current energy consumption of the frequency conversion controller 8 is greater than or equal to the previous energy consumption of the frequency conversion controller 8, stop the gradual adjustment, and adjust the carrier frequency of the frequency conversion controller 8 to the previous carrier frequency gear;

[0084] The current energy consumption of the frequency conversion controller 8 is the energy consumption when the frequency conversion controller 8 is in the current carrier frequency gear; the previous energy consumption of the frequency conversion controller 8 is the energy consumption when the frequency conversion controller 8 is in the previous carrier frequency gear.

[0085] In some embodiments, the speed of the compressor 1 is divided into multiple speed levels according to the speed level, and the target speed level is one of the multiple speed levels. For example, the target speed level may be the speed level corresponding to the user's cooling demand. In another example, the target speed level may be the speed level corresponding to the received speed level command.

[0086] The carrier frequency corresponding to each speed gear of the compressor is divided into multiple carrier frequency gears according to the size of the carrier frequency. "Gradually adjusting" the carrier frequency gear of the frequency conversion controller 8 means adjusting the carrier frequency to each carrier frequency gear in sequence according to the order of the carrier frequency gears. For example, when the target speed gear corresponds to n carrier frequency gears from 1 to n, "gradually adjusting" the carrier frequency of the frequency conversion controller 8 to the next carrier frequency gear means first adjusting from the first carrier frequency gear to the second carrier frequency gear, then adjusting from the second carrier frequency gear to the third carrier frequency gear, and so on, until the current energy consumption of the frequency conversion controller 8 is greater than or equal to the previous energy consumption of the frequency conversion controller 8. In other words, by "gradually adjusting" the carrier frequency gear, the carrier frequency with the lowest energy consumption is selected, so that the frequency conversion controller 8 operates at the carrier frequency with the lowest energy consumption.

[0087] In some embodiments of the present application, the compressor 1 is first controlled to run to the target speed gear. For example, the compressor 1 can be controlled to run to the target speed gear according to the refrigeration demand or the received speed gear instruction. Then, when the compressor 1 is at the target speed gear, the carrier frequency of the frequency conversion controller 8 is gradually adjusted to the next carrier frequency gear until the current energy consumption of the frequency conversion controller 8 is greater than or equal to the previous energy consumption of the frequency conversion controller 8, and the gradual adjustment is stopped. Finally, the carrier frequency of the frequency conversion controller 8 is adjusted to the previous carrier frequency gear. The adjustment here includes increasing or decreasing. By gradually increasing or decreasing the carrier frequency of the frequency conversion controller, the optimized learning of the carrier frequency is realized, and then the variable carrier frequency control is realized to improve the energy saving effect.

[0088] For example, when the compressor 1 is in the target speed gear, the carrier frequency of the frequency conversion controller 8 is gradually increased, and the energy consumption of the frequency conversion controller 8 is monitored at the same time, until the current energy consumption of the frequency conversion controller 8 is greater than or equal to the previous energy consumption of the frequency conversion controller 8, the increase is stopped, and the carrier frequency of the frequency conversion controller 8 is controlled to return to the previous carrier frequency.

[0089] Among them, the current energy consumption of the frequency conversion controller 8 is the energy consumption when the frequency conversion controller 8 is in the current carrier frequency gear, that is, when the compressor 1 is in the target speed gear and the carrier frequency of the frequency conversion controller 8 is the current carrier frequency gear, the energy consumption of the frequency conversion controller 8; the previous energy consumption of the frequency conversion controller 8 is the energy consumption when the frequency conversion controller 8 is in the previous carrier frequency gear, that is, when the compressor 1 is in the target speed gear and the carrier frequency of the frequency conversion controller 8 is the previous carrier frequency gear, the energy consumption of the frequency conversion controller 8.

[0090] The control object involved in the embodiment of the present application is the carrier frequency in the variable frequency drive (the fundamental frequency for generating alternating current), which is the output control of the variable frequency controller. Different carrier frequencies can be distributed for each target speed gear. By calculating the energy consumption at the target speed gear, the carrier frequency is adjusted with the minimum energy consumption as a reference to achieve improved drive efficiency and harmonic performance, optimize system control, improve system efficiency, and enhance energy saving effects. In the embodiment of the present application, the carrier frequency switches with the speed to achieve energy saving and consumption reduction, reduce the energy consumption of the refrigerator at low speed, improve the energy efficiency ratio, and better improve performance at high speed to meet application requirements.

[0091] For example, refer to FIG4 , which is a workflow diagram of the frequency conversion controller 8 provided in some embodiments of the present application. The frequency conversion controller 8 is configured to execute steps S11 to S16 .

[0092] S11, controlling the compressor 1 to run to the target speed gear;

[0093] S12, adjusting the carrier frequency of the frequency conversion controller 8 to fn, and calculating the energy consumption Qn when the carrier frequency is fn, wherein n is a positive integer greater than or equal to 1, and fn can be understood as the carrier frequency value of the nth carrier frequency gear;

[0094] S13, adjusting the carrier frequency of the frequency conversion controller 8 to fn+1, and calculating the energy consumption Qn+1 when the carrier frequency is fn+1;

[0095] S14, determining whether the energy consumption Qn+1 is greater than or equal to the energy consumption Qn;

[0096] S15, if yes, adjust the carrier frequency of the frequency conversion controller 8 to fn;

[0097] S16. If not, add 1 to the value of n, that is, n in the above step becomes n+1, and return to step S13.

[0098] In some embodiments, as shown in FIG. 5 , the refrigerator further includes a voltage acquisition device 9 , which is connected to the frequency conversion controller 8 and is configured to acquire a current input voltage of the frequency conversion controller 8 .

[0099] The refrigerator further includes a current collecting device 10 , which is connected to the frequency conversion controller 8 and is configured to collect the current output current of the frequency conversion controller 8 .

[0100] The frequency conversion controller 8 is further configured to:

[0101] Acquire the current input voltage of the frequency conversion controller 8 collected by the voltage collection device 9;

[0102] Acquire the current output current of the frequency conversion controller 8 collected by the current collection device 10;

[0103] The current energy consumption of the frequency conversion controller 8 is calculated according to the current input voltage and the current output current.

[0104] It is understood that the energy consumption of the frequency conversion controller 8 can be calculated by collecting the input current and output voltage of the frequency conversion controller 8. In the embodiment of the present application, the refrigerator further includes a voltage collection device 9 and a current collection device 10, which are respectively configured to collect the input voltage and output current of the frequency conversion controller 8 and calculate the energy consumption of the frequency conversion controller 8 based on the input voltage and output current. The calculation method of the previous energy consumption of the frequency conversion controller 8 is similar to the calculation method of the current energy consumption of the frequency conversion controller 8 and will not be repeated here.

[0105] For example, see FIG6 , which is a flowchart of a frequency conversion controller 8 provided in some embodiments of the present application. The frequency conversion controller 8 is configured to execute steps S21 to S23:

[0106] S21, obtaining the current input voltage of the frequency conversion controller 8 collected by the voltage collection device 9;

[0107] S22, obtaining the current output current of the frequency conversion controller 8 collected by the current collection device 10;

[0108] S23. Calculate the current energy consumption of the frequency conversion controller 8 according to the current input voltage and the current output current.

[0109] In some embodiments, the frequency conversion controller 8 is configured to calculate the current energy consumption of the frequency conversion controller 8 according to the following formula: Q = ∫U*Idt+K1*f+K2*I+Q0

[0110] Among them, U is the current input voltage of the frequency converter, I is the current output current of the frequency converter, K1 is the preset switching loss coefficient, K2 is the preset operating power consumption coefficient, f is the carrier frequency when the frequency converter is in the current carrier frequency gear at the target speed gear, and Q0 is the preset static power consumption of the frequency converter 8.

[0111] In some embodiments of the present application, the energy consumption of the frequency conversion controller 8 is calculated using the formula Q=∫U*Idt+K1*f+K2*I+Q0, thereby achieving accurate calculation of the power consumption 8 of the frequency conversion controller within an error range of 5%.

[0112] In some embodiments, referring to FIG7 , the current collection device 10 includes:

[0113] A current amplifier circuit 101, wherein a first input terminal of the current amplifier circuit 101 is configured to receive a power device current IBUS, a second input terminal of the current amplifier circuit 101 is respectively connected to a first terminal of a first resistor R1 and a first terminal of a bias circuit 102, and an output terminal of the current amplifier circuit 101 is respectively connected to a second terminal of the bias circuit 102 and a first terminal of a second resistor R2;

[0114] The first resistor R1, a second end of the first resistor R1 is grounded;

[0115] The bias circuit 102;

[0116] the second resistor R2, wherein the second end of the second resistor R2 is connected to the first end of the first capacitor C1; and

[0117] The first capacitor C1 has a first end connected to the first sampling pin of the frequency conversion controller 8 , and a second end of the first capacitor C1 is grounded.

[0118] In one example, as shown in FIG7 , the current amplification circuit 101 includes an amplifier OA, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The first end of the third resistor R3 is connected to the first end of the fourth resistor R4, and the second end of the third resistor R3 is connected to the second end of the first resistor R1. The first end of the third resistor R3 is also configured to receive the power device current IBUS, and the second end of the third resistor R3 is also grounded. The second end of the fourth resistor R4 is respectively connected to the first input terminal OA_P of the amplifier OA, the first end of the fifth resistor R5, and the first end of the sixth resistor R6. The second end of the fifth resistor R5 is used to receive a voltage, such as a 5V voltage. The second end of the sixth resistor R6 is grounded. The bias unit 102 includes a seventh resistor R7 and an eighth resistor R8. The first end of the seventh resistor R7 and the first end of the eighth resistor R8 are both connected to the second input terminal OA_N of the amplifier OA, and the second end of the seventh resistor R7 and the second end of the eighth resistor R8 are both connected to the output terminal OA_OUT of the amplifier OA.

[0119] In some embodiments of the present application, current collection is performed by providing a current collection device including a first resistor R1, a second resistor R2, the third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, an amplifier OA, and a first capacitor C1. IBUS is the confluence point of the power device currents.

[0120] In some embodiments, as shown in FIG8 , the voltage acquisition device 9 includes:

[0121] a resistance unit 901 , wherein a first end of the resistance unit 901 is configured to be connected to a voltage VBUS, and a second end of the resistance unit 901 is connected to a first end of a ninth resistor R9 ;

[0122] a ninth resistor R9, wherein a first end of the ninth resistor R9 is further connected to the first end of the second capacitor C2, and a second end of the ninth resistor R9 is grounded;

[0123] The second capacitor C2, the first end of the second capacitor C2 is also connected to the second sampling pin AD_Vbus of the frequency conversion controller 8, and the second end of the second capacitor C2 is grounded.

[0124] In some embodiments of the present application, voltage acquisition is performed by providing a voltage acquisition device including a resistor unit, a ninth resistor R9 and a second capacitor C2. The voltage VBUS received by the voltage acquisition device 9 may be a bus voltage after rectification and filtering.

[0125] In some embodiments, as shown in FIG9 , the resistance unit includes a tenth resistor R10 , an eleventh resistor R11 , and a twelfth resistor R12 connected in sequence.

[0126] In a refrigerator provided by some embodiments of the present application, a frequency conversion controller gradually adjusts the carrier frequency of the frequency conversion controller to a next carrier frequency gear while controlling the compressor to be at a target speed gear, until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, stops the gradual adjustment, and adjusts the carrier frequency of the frequency conversion controller to the previous carrier frequency gear, thereby realizing variable carrier frequency control and improving energy-saving effects.

[0127] In addition, referring to FIG10 , FIG10 is a flow chart of a refrigerator control method provided by an embodiment of the present application. The refrigerator includes at least a compressor and a frequency conversion controller. The refrigerator control method includes:

[0128] S1, controlling the compressor to run to a target speed gear;

[0129] S2. When the compressor is at the target speed gear, gradually adjust the carrier frequency of the frequency conversion controller to the next carrier frequency gear until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, stop the gradual adjustment, and adjust the carrier frequency of the frequency conversion controller to the previous carrier frequency gear;

[0130] The current energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the current carrier frequency gear; the previous energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the previous carrier frequency gear.

[0131] In some embodiments of the present application, the compressor is first controlled to run to the target speed gear. For example, the compressor can be controlled to run to the target speed gear according to the cooling demand or the received speed gear instruction. Then, when the compressor is at the target speed gear, the carrier frequency of the frequency conversion controller is gradually adjusted to the next carrier frequency gear until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, and the gradual adjustment is stopped. Finally, the carrier frequency of the frequency conversion controller is adjusted to the previous carrier frequency gear. The adjustment here includes increasing or decreasing; by gradually increasing or decreasing the carrier frequency of the frequency conversion controller, the optimized learning of the carrier frequency is realized, and then the variable carrier frequency control is realized to improve the energy saving effect.

[0132] For example, when the compressor is at the target speed gear, the carrier frequency of the frequency conversion controller is gradually increased, and the energy consumption of the frequency conversion controller is monitored at the same time, until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, the carrier frequency is stopped from being increased, and the carrier frequency of the frequency conversion controller is controlled to return to the previous carrier frequency.

[0133] Among them, the current energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the current carrier frequency gear, that is, the energy consumption of the frequency conversion controller when the compressor is in the target speed gear and the carrier frequency of the frequency conversion controller is the current carrier frequency gear; the previous energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the previous carrier frequency gear, that is, the energy consumption of the frequency conversion controller when the compressor is in the target speed gear and the carrier frequency of the frequency conversion controller is the previous carrier frequency gear.

[0134] In some embodiments of the present application, the control object involved is the carrier frequency (the fundamental frequency for generating alternating current) in the variable frequency drive, which is the output control of the variable frequency controller. Different carrier frequencies can be distributed for each target speed gear. By calculating the energy consumption at the target speed gear, the carrier frequency is adjusted with the minimum energy consumption as a reference to achieve improved drive efficiency and harmonic performance, optimize system control, improve system efficiency, and enhance energy saving effects. In some embodiments of the present application, the carrier frequency switches with the speed to achieve energy saving and consumption reduction, reduce the energy consumption of the refrigerator at low speeds, improve the energy efficiency ratio, and better improve performance at high speeds to meet application requirements.

[0135] In some embodiments, the refrigerator further includes a voltage acquisition device, which is connected to the frequency conversion controller and is configured to acquire a current input voltage of the frequency conversion controller.

[0136] The refrigerator further comprises a current collecting device, which is connected to the frequency conversion controller and is used to collect the current output current of the frequency conversion controller.

[0137] The refrigerator control method further includes:

[0138] Acquiring the current input voltage collected by the voltage collection device;

[0139] Acquiring the current output current collected by the current collection device;

[0140] The current energy consumption of the frequency conversion controller is calculated according to the current input voltage and the current output current.

[0141] It is understood that the energy consumption of the frequency converter can be calculated by collecting the input current and output voltage of the frequency converter. In some embodiments of the present application, the refrigerator further includes a voltage collection device and a current collection device, each configured to collect the input voltage and output current of the frequency converter, and calculate the energy consumption of the frequency converter based on the input voltage and output current. The calculation method for the previous energy consumption of the frequency converter is similar to the calculation method for the current energy consumption of the frequency converter, and will not be repeated here.

[0142] In some embodiments, the refrigerator control method further includes:

[0143] The current energy consumption of the frequency conversion controller is calculated according to the following formula: Q = ∫U*Idt+K1*f+K2*I+Q0

[0144] Among them, U is the current input voltage of the frequency converter, I is the current output current of the frequency converter, K1 is the preset switching loss coefficient, K2 is the preset operating power consumption coefficient, f is the carrier frequency when the frequency converter is in the current carrier frequency gear at the target speed gear, and Q0 is the preset static power consumption of the frequency converter.

[0145] In some embodiments of the present application, a preset formula is provided to calculate the energy consumption of the frequency converter. Using the formula Q = ∫U*Idt+K1*f+K2*I+Q0, the energy consumption of the frequency converter is calculated, improving the accuracy of the frequency converter power consumption calculation to within a 5% error range.

[0146] In some embodiments, as shown in FIG7 , the current collection device includes:

[0147] a current amplifying circuit, wherein a first input end of the current discharging circuit is configured to receive the current of the power device, a second input end of the current amplifying circuit is respectively connected to a first end of the first resistor and a first end of the bias circuit, and an output end of the current amplifying circuit is respectively connected to a second end of the bias circuit and a first end of the second resistor;

[0148] The second end of the first resistor is grounded;

[0149] the bias circuit;

[0150] The second resistor, a second end of which is connected to the first end of the first capacitor;

[0151] The first capacitor has a first end connected to the first sampling pin of the frequency conversion controller, and a second end of the first capacitor is grounded.

[0152] In one example, as shown in FIG8 , the current amplification unit includes an amplifier OA, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The first end of the third resistor R3 is connected to the first end of the fourth resistor R4, and the second end of the third resistor R3 is connected to the second end of the first resistor R1. The first end of the third resistor R3 is also configured to receive the power device current IBUS, and the second end of the third resistor R3 is also configured to be grounded. The second end of the fourth resistor R4 is respectively connected to the first input terminal OA_P of the amplifier OA, the first end of the fifth resistor R5, and the first end of the sixth resistor R6. The second end of the fifth resistor R5 is configured to receive a voltage, for example, a 5V voltage. The second end of the sixth resistor R6 is grounded. The bias circuit includes a seventh resistor R7 and an eighth resistor R8. The first end of the seventh resistor R7 and the first end of the eighth resistor R8 are both connected to the second input terminal OA_N of the amplifier OA, and the second end of the seventh resistor R7 and the second end of the eighth resistor R8 are both connected to the output terminal OA_OUT of the amplifier OA.

[0153] In some embodiments of the present application, current collection is performed by providing a current collection device including a first resistor R1, a second resistor R2, the third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, an amplifier OA, and a first capacitor C1. IBUS is the confluence point of the power device currents.

[0154] In some embodiments, as shown in FIG9 , the voltage acquisition device includes:

[0155] a resistance unit, wherein a first end of the resistance unit is configured to be connected to a voltage, and a second end of the resistance unit is connected to a first end of a ninth resistor;

[0156] the ninth resistor, wherein a first end of the ninth resistor is further connected to the first end of the second capacitor, and a second end of the ninth resistor is grounded;

[0157] The second capacitor has a first end connected to the second sampling pin of the frequency conversion controller, and a second end connected to the ground.

[0158] As shown in Figure 8 , in some embodiments of the present application, voltage acquisition is performed by providing a voltage acquisition device including a resistor unit, a ninth resistor R9, and a second capacitor C2. The input voltage VBUS can be a rectified and filtered bus voltage. In some embodiments, as shown in Figure 10 , the resistor unit includes a tenth resistor R10, an eleventh resistor R11, and a twelfth resistor R12 connected in sequence.

[0159] Some embodiments of the present application provide a refrigerator control method, in which a frequency conversion controller gradually adjusts the carrier frequency of the frequency conversion controller to a next carrier frequency gear while controlling the compressor to be at a target speed gear, until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, stops the gradual adjustment, and adjusts the carrier frequency of the frequency conversion controller to the previous carrier frequency gear, thereby realizing variable carrier frequency control and improving energy saving effects.

[0160] Household refrigerators and freezers may also be used in high-temperature and embedded environments. In these scenarios, the system's heat exchange efficiency is low and the heat dissipation space is limited. To meet cooling requirements, the compressor must run for extended periods, causing the temperature of the compressor and inverter board to rise. Power devices like IGBTs (Insulated Gate Bipolar Transistors) can reach their temperature limits and fail. Temperature control of the inverter board is crucial during design to address the issue of temperature rise affecting heat dissipation performance. For example, after a VFD controller reaches a certain power output, the temperature of the power devices on the controller will increase over time. If the temperature exceeds the limit, the power devices will be damaged. Related technologies typically install NTC (Negative Temperature Coefficient) thermistors on the VFD to sample the power device temperature. The compressor speed is then reduced before the temperature reaches the limit. However, this approach rarely achieves the desired effect, primarily because the temperature increase of the VFD power device and the speed are not linearly related. Simply adjusting the compressor speed results in poor cooling performance.

[0161] Based on this, some embodiments of the present application also provide a refrigerator that uses PID control to achieve the heat dissipation process of the frequency conversion controller without adding heat dissipation devices. The control accuracy is high and the deviation is small, which can avoid the phenomenon of ultra-high temperature failure of power devices on the frequency conversion controller.

[0162] Figure 11 is a schematic diagram of the external structure of a refrigerator 100 provided in some embodiments, Figure 12 is a schematic diagram of the internal structure of a refrigerator 100 provided in some embodiments, and Figure 13 is a schematic diagram of the structure of the refrigeration system in the refrigerator in some embodiments. For an introduction to the refrigerator structure and the operation of the refrigeration system, please refer to the previous embodiments and will not be repeated here.

[0163] 14 is a schematic diagram of the structure of a compressor compartment 11 in a refrigerator according to some embodiments of the present application. A compressor 1 and a condenser 2 are disposed in the compressor compartment 11.

[0164] In some embodiments, an evaporating dish 12 is further disposed within the compressor compartment 11. The evaporating dish 12 is configured to receive defrost water (i.e., water formed by melting frost in the refrigerator). Exemplarily, the evaporating dish 13 is configured to receive defrost water from the freezer compartment and / or defrost water from the evaporator 6. The evaporating dish 13 is secured to the bottom wall of the compressor compartment 11 and is a box-like structure with an open top. The evaporating dish 12 comprises a horizontally disposed bottom plate and side panels extending upward from the edges of the bottom plate. Together, the bottom plate and side panels form a box-like structure with an open top.

[0165] The condenser 2 is arranged vertically, with its top end abutting against the top surface of the compressor compartment 11. This allows the condenser 2 to fit within the compressor compartment 11 while minimizing the height of the compressor compartment 11, thereby increasing the storage compartment's volume. The condenser 2 and compressor 1 are spaced apart in the horizontal direction. The bottom plate of the evaporating dish 12 is formed with protruding fixing posts, to which the bottom end of the condenser 2 is secured, either directly or via connectors, securing the condenser 2 within the evaporating dish 12 and ensuring that the bottom end of the condenser 2 is above the defrost water level within the evaporating dish 12.

[0166] The refrigerator 100 is also provided with a fan 13 for heat dissipation. A through hole (not shown) is provided on the side of the compressor compartment 11 facing the fan 13. The refrigerator 100 is provided with an exhaust vent corresponding to the outlet of the fan 13. In some embodiments, the fan 13 is a centrifugal fan, with the left and right sides of the centrifugal fan respectively attached to the compressor compartment 11. The inlet of the centrifugal fan is provided in the through hole of the compressor compartment 11, so that the air in the compressor compartment 11 is discharged from the compressor compartment 11 through the inlet of the centrifugal fan.

[0167] 15 , which is a schematic diagram illustrating a connection between a frequency conversion controller 8 and a compressor 1 according to some embodiments of the present application, wherein the frequency conversion controller 8 is provided with a main controller 14 and a PID controller 15. In some embodiments, the main controller 14 may be a microcontroller unit (MCU).

[0168] The main controller 14 is configured to collect the operating parameters of the compressor 1, such as real-time speed, electrical parameters, etc. Based on these operating parameters, the operating status of the compressor 1 can be monitored, and timely warnings can be given when the compressor fails. In addition, the main controller 14 can control the start and stop of the compressor 1. The main controller 14 can also process and calculate the collected data, such as calculating the output power based on the electrical parameters of the motor in the frequency conversion controller 8. The main controller 14 inputs the calculated and processed data into the PID controller 15 for PID control. Since the temperature of the power device (such as MCU) on the frequency conversion controller 8 will increase over time after reaching a certain output power, if the limit temperature is exceeded, the power device will be damaged. In order to prevent the temperature from rising, when the frequency conversion controller 8 works to a certain output power, the frequency conversion controller 8 is output at a constant power through the PID control link to avoid the problem of rising power device temperature. In addition, the preset power reference value (the corresponding value after each frequency conversion controller hardware is determined) is used as the target power, and the target power is compared with the output power obtained by actual calculation. The PID adjustment method is used to adjust the speed of the compressor to improve the accuracy of speed control.

[0169] In some embodiments, the frequency conversion controller is configured to: obtain the electrical parameters of the motor in the frequency conversion controller, and calculate the output power based on the electrical parameters and preset frequency conversion characteristic parameters; when the output power does not match the preset target power, the output power is used as the input of the PID controller, and through PID adjustment, a reference speed is output to the compressor so that the compressor operates according to the reference speed.

[0170] For example, see Figure 16, which is a flowchart of a frequency conversion controller in a refrigerator according to some embodiments of the present application. The frequency conversion controller is configured to execute steps S161 to S166.

[0171] S161. Determine whether the compressor is started; if so, execute step S162; if not, continue to execute step S161.

[0172] S162: After the compressor is started, the frequency conversion controller begins to obtain electrical parameters of the motor in the frequency conversion controller.

[0173] S163. Calculate the output power of the frequency conversion controller based on the electrical parameters and preset frequency conversion characteristic parameters.

[0174] The frequency conversion characteristic parameter is a preset value and can be pre-set according to the model of different frequency conversion controllers.

[0175] S164: Determine whether the calculated output power of the frequency conversion controller matches the target power. If not, proceed to step S165; if so, return to step S162.

[0176] Since each frequency conversion controller pre-stores a corresponding target power, the output power can be compared with the target power.

[0177] S165: Using the output power as the input of a PID controller, and outputting a reference speed through PID regulation.

[0178] If the calculated output power does not match the target power, the output power is input into the PID controller for proportional, integral, and differential control to ensure that the output power of the variable frequency controller matches the target power. When the output power matches the target power, a reference speed is output based on the output power so that the compressor operates at the reference speed.

[0179] S166: The compressor operates at the reference speed.

[0180] Exemplarily, the electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value. Referring to Figure 17, Figure 17 is a schematic diagram of a PID control link provided in some embodiments of the present application. After power calculation is performed based on the q-axis current measurement value Iq, the q-axis voltage measurement value Uq, the d-axis current measurement value Id, and the d-axis voltage measurement value Ud, the output power P of the frequency conversion controller is obtained, and then this output power P is compared with the target power Pmax. When the output power P is inconsistent with the target power Pmax, the output power P is input into the PID controller for PID control so that the output power of the frequency conversion controller matches the target power. When the output power matches the target power, the reference speed is output based on this output power so that the compressor operates at the reference speed.

[0181] In some embodiments, the PID controller parameters are set based on the ambient temperature. For example, when the ambient temperature is 25°C, the PID controller parameters are set as follows: Kp = 1.2, Ti = 0.5, and Td = 0.1. At this point, the compressor speed stabilizes at 2000 ± 50 rpm, and the variable frequency controller temperature stabilizes at 65 ± 2°C. This ensures that the variable frequency controller temperature does not exceed the maximum temperature of the power devices, reducing the risk of damage to the power devices due to overheating.

[0182] It's worth noting that in the early development of motor drive speed control systems, DC drives enabled stepless speed regulation to achieve optimal motor performance. To achieve this same effect with AC speed control drives, frequency converters emerged. Frequency converter designers shifted the electric drive of three-phase asynchronous motors to that of DC motors, achieving this through "decoupling" the d-axis and q-axis. Typically, DC motor drive controls its rotor current and field current. In frequency converter AC speed control systems, the "q-axis" corresponds to the DC motor's rotor electrical specifications, and the "d-axis" corresponds to the DC motor's field electrical specifications. The q-axis and d-axis are not motor axes, but rather mathematical coordinate axes. These coordinates rotate synchronously with rotor rotation, effectively establishing a coordinate system on the motor rotor. This allows the motor's mathematical model to be converted to this coordinate system, with the rotor magnetic field oriented along the d-axis and the direction perpendicular to the rotor magnetic field along the q-axis.

[0183] In some embodiments, the output power is calculated based on the electrical parameters and the preset frequency conversion characteristic parameters, including: calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power; calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power; calculating the sum of the q-axis power and the d-axis power and the product of the frequency conversion characteristic parameters to obtain the output power.

[0184] For example, see FIG18 , which is another workflow diagram of the frequency conversion controller in the refrigerator provided in some embodiments of the present application, wherein step S163 includes steps S1631 to S1633 .

[0185] S1631. Calculate the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power.

[0186] S1632: Calculate the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain d-axis power.

[0187] S1633 . Calculate the product of the sum of the q-axis power and the d-axis power and the frequency conversion characteristic parameter to obtain the output power.

[0188] In some embodiments, the output power is calculated according to the following formula: P=K*(Iq*Uq+Id*Ud);

[0189] Among them, P is the output power; K is the frequency conversion characteristic parameter, which is a preset value and can be pre-set according to the model of different frequency conversion controllers; Iq is the q-axis current measurement value; Uq is the q-axis voltage measurement value; Id is the d-axis current measurement value; Ud is the d-axis voltage measurement value.

[0190] In some embodiments, the variable frequency controller is further configured to calculate the back electromotive force of the motor and perform field weakening control on the motor when the back electromotive force generated by the motor is greater than a preset value. In some embodiments, the preset value may be the bus voltage, or the product of the bus voltage and a preset coefficient k, where k is less than 1, for example, a value range of k is 0.95-0.97.

[0191] Weak magnetic control of a motor means that when the motor speed increases and the back electromotive force approaches or exceeds a preset value (for example, the preset value can be the product of the bus voltage value and a preset coefficient k, where k<1, for example, the value range of K can be 0.95 to 0.97), the motor current or magnetic field strength is adjusted to make the motor's magnetic field strength lower than its rated value, that is, the back electromotive force is reduced by actively reducing the motor's magnetic field strength.

[0192] For example, in some motor control methods, the motor magnetic field strength will always be maintained at a high level, which will cause energy waste and increase the motor temperature, and will also reduce the motor's accuracy and life. The weak magnetic control algorithm can allow the motor to operate in a low magnetic field, reduce energy loss and motor temperature, and improve the efficiency and accuracy of the motor. By adjusting the motor's current and magnetic field strength, the motor can still maintain a stable speed and load carrying capacity under a low magnetic field. In some embodiments, the weak magnetic control algorithm can monitor the motor's magnetic field strength in real time by estimating the motor's back electromotive force value, flux observer, predictive control, and model reference adaptive control, and adjust the motor's current and magnetic field strength in time. In this way, the motor can maintain stable operation under a low magnetic field, thereby achieving energy saving and consumption reduction, improving accuracy and extending the motor's life. The frequency conversion controller monitors the motor speed in real time. When the back electromotive force generated by the motor speed is greater than the bus voltage, the rotor magnetic field is weakened to obtain a higher speed.

[0193] See Figure 19, which is a schematic diagram of the FOC (Field-Oriented Control) framework of the motor in the variable frequency controller provided in some embodiments of the present application. FOC, or field-oriented control or vector control, is a control technology in the field of motor control and one of the more advanced motor control methods currently available. The working principle of FOC is to control the current vector of the motor in the direction of the motor's stator electromagnetic field so that the direction of the motor's torque is consistent with the direction of the rotor magnetic field, thereby ensuring that the rotational torque output by the motor is maximized, thereby ensuring operating efficiency and performance. The FOC control method regards the rotor's magnetic field as a rotating vector and controls the motor's magnetic field by counter-rotating a fixed vector of the same frequency, thereby achieving control of the motor.

[0194] For example, after the PID controller 15 outputs the reference speed, PI control is performed on the q-axis electrical parameters, and field weakening control is performed on the d-axis electrical parameters. PI control requires the addition of a q-axis reference current Iqref, while field weakening control requires the addition of a d-axis reference current Idref. After PI control, a q-axis voltage Uq is output, and after field weakening control, a d-axis voltage Ud is output. Then, an inverse Park transform is performed on the q-axis voltage Uq and the d-axis voltage Ud. Among them, in the FOC framework, Park transform is the process of converting variables in the α, β coordinate system (two-phase stationary coordinate system) into variables in the d, q coordinate system (two-phase rotating coordinate system); inverse Park transform is the process of converting variables in the d, q coordinate system into the α, β coordinate system; Clark transform is the process of converting variables in the a, b, c coordinate system (three-phase stationary coordinate system) into the α, β coordinate system. The existence of the α-axis and the β-axis allows the three-phase current (Ia, Ib, Ic) to be represented by two variables (Iα, Iβ), and the three-phase voltage (Ua, Ub, Uc) to be represented by two variables (Vα, Vβ). Without one variable, α and β are vertical and orthogonal, but Iα and Iβ are still sinusoidal, so it is still difficult to use PID control. Then we continue to transform them into linear quantities. This is the work to be completed by the Park transform and inverse Park transform. Inverse Park transform converts Ud and Uq to Vα and Vβ after PI control. Park transform converts Iα and Iβ to Id and Iq after acquiring the motor current and passing it to the PI controller. The FOC diagram shows that Park and Inverse Park exist for PI control.

[0195] In some embodiments, referring to FIG19 , the variable frequency controller further includes a three-phase bridge, which is connected to the PID controller and the compressor. The three-phase bridge comprises a bridge circuit composed of several insulated gate bipolar transistors (IGBTs). R represents a sampling resistor, which can sample Ia, Ib, and Ic. In some embodiments, the three-phase bridge comprises a bridge circuit composed of six insulated gate bipolar transistors (IGBTs).

[0196] For example, the electrical parameters are subjected to inverse Park transformation and then SVW modulation before being input into the three-phase bridge. SVPWM (Space Vector Pulse Width Modulation), also known as space vector pulse width modulation, is abbreviated as SVW. SVPWM is a pulse width modulation wave generated by a specific switching mode composed of six power switching elements of a three-phase power inverter, which can make the output current waveform as close to the ideal sinusoidal waveform as possible. Space voltage vector PWM is different from traditional sinusoidal PWM. It starts from the overall effect of the three-phase output voltage and focuses on how to make the motor obtain an ideal circular magnetic flux trajectory. Compared with SPWM, SVPWM technology has a smaller harmonic component in the winding current waveform, which reduces the motor torque pulsation and makes the rotating magnetic field closer to a circle. It also greatly improves the utilization rate of the DC bus voltage and is easier to digitize.

[0197] The refrigerator disclosed in some embodiments of the present application adds a PID control link in the frequency conversion controller. Without adding heat dissipation devices, the PID control method is used to realize the heat dissipation process of the frequency conversion controller. The control accuracy is high and the deviation is small, which can avoid the phenomenon of excessive high temperature failure of the power devices on the frequency conversion controller.

[0198] Refer to Figure 20, which is a flowchart of a compressor speed control method for a refrigerator provided in some embodiments of the present application. The compressor speed control method is executed by a frequency conversion controller in the refrigerator, and the compressor speed control method includes the following steps.

[0199] S201, obtaining electrical parameters of a motor in a frequency conversion controller, and calculating output power based on the electrical parameters and preset frequency conversion characteristic parameters;

[0200] S202. When the output power does not match the preset target power, the output power is used as the input of the PID controller, and a reference speed is output to the compressor through PID regulation, so that the compressor operates at the reference speed.

[0201] In some embodiments, the electrical parameters include a q-axis current measurement, a q-axis voltage measurement, a d-axis current measurement, and a d-axis voltage measurement.

[0202] In some embodiments, the output power is calculated based on the electrical parameters and the preset frequency conversion characteristic parameters, including: calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power; calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power; calculating the power sum of the q-axis power and the d-axis power and the product of the frequency conversion characteristic parameters to obtain the output power.

[0203] In some embodiments, the method further includes: calculating the back electromotive force of the motor; and performing magnetic weakening control on the motor when the back electromotive force generated by the motor is greater than a preset value.

[0204] In some embodiments, the preset value is a bus voltage value, or a product of the bus voltage value and a preset coefficient, wherein the preset coefficient is less than 1, for example, the preset coefficient is 0.95-0.97.

[0205] It is worth noting that the specific working process of the refrigerator compressor speed control method described in some embodiments of the present application can refer to the working process of the controller described in the above embodiments, and will not be repeated here.

[0206] Some embodiments of the present application disclose a refrigerator compressor speed control method, which adds a PID control link in the frequency conversion controller. Without adding heat dissipation devices, the PID control method is used to realize the heat dissipation process of the frequency conversion controller. The control accuracy is high and the deviation is small, which can avoid the phenomenon of excessive high temperature failure of the power devices on the frequency conversion controller.

[0207] The compressor drive power supply for inverter refrigerators and freezers utilizes a variable frequency circuit to enhance performance, offering advantages such as faster cooling, minimal temperature fluctuation, low energy consumption, and low-frequency startup and quiet operation. However, during operation, the switching of power devices in the inverter circuit generates significant electromagnetic interference. If a user's home is equipped with a GFCI (Ground Fault Circuit Interrupter) outlet, the inverter refrigerator, powered by such an outlet, may trip the GFCI due to non-power-frequency leakage current. The carrier frequency of inverter controllers currently ranges from 4 to 6 kHz. The noise interference caused by the switching power devices in this frequency range falls within the high-frequency sensitive region of GFCI operation. Combined with grid interference, this can easily cause the GFCI to falsely trigger, resulting in malfunction of inverter refrigerators and freezers in this frequency range, leading to customer complaints or product returns.

[0208] Based on this, some embodiments of the present application also provide a refrigerator that can increase the carrier frequency (switching power device frequency) of the frequency conversion controller, adjust the output carrier frequency of the frequency conversion controller, make the refrigerator compatible with GFCI, and increase the PWM (Pulse Width Modulation) carrier frequency of the frequency conversion controller, which can effectively curb the tripping phenomenon.

[0209] For example, the structure of the refrigerator is shown in Figures 1 and 2, and can also be shown in Figures 11 to 13. The structure of the refrigerator and the working principle of the refrigeration system can be referred to the previous embodiments and will not be repeated here.

[0210] In some embodiments, the inverter controller 8 of the refrigerator is configured to: obtain leakage current from the power input terminal of the refrigerator, as detected by a sampling circuit; when the leakage current is greater than a preset current threshold, calculate the current difference between the leakage current and the current threshold; determine a carrier frequency boost amount for the inverter controller based on the current difference, and adjust the carrier frequency of the inverter controller based on the carrier frequency boost amount. Increasing the carrier frequency of the inverter controller based on the carrier frequency boost amount can effectively prevent tripping, making the refrigerator compatible with GFCI.

[0211] For example, see Figure 21, which is a workflow diagram of the frequency conversion controller in the refrigerator provided in an embodiment of the present application, and the frequency conversion control is configured to execute steps S211 to S215.

[0212] S211. Confirm whether the refrigerator is turned on. If so, execute step S212; if not, continue to execute step S211.

[0213] S212: After the refrigerator is started, the frequency conversion controller starts to obtain the leakage current of the power input terminal collected by the sampling circuit.

[0214] The power input end is the L (live wire) and N (neutral wire) wires of the power input.

[0215] S213: After obtaining the leakage current, compare the leakage current value with a preset current threshold to determine whether the leakage current value is greater than the preset current threshold. If so, proceed to step S214; if not, proceed to step S212.

[0216] If the leakage current value is less than or equal to the current threshold, it indicates that the leakage current is very low or does not exist, the GFCI will not trip or the risk of tripping is very low, and the frequency converter maintains the original operating mode. If the leakage current value is greater than the current threshold, it indicates that the leakage current is high and the risk of GFCI tripping is very high, and step S214 is executed.

[0217] S214: Calculate a current difference between the leakage current value and the current threshold.

[0218] S215 . Determine a carrier frequency increase amount of the frequency conversion controller according to the current difference, and adjust the carrier frequency of the frequency conversion controller according to the carrier frequency increase amount.

[0219] In some embodiments, a correspondence between the current difference and the carrier frequency boost is pre-set in the frequency conversion controller. Therefore, after obtaining the current difference, the carrier frequency boost can be determined according to the correspondence, and then the carrier frequency boost is increased on the basis of the current carrier frequency to obtain the adjusted carrier frequency boost.

[0220] It is understandable that since the current carrier frequency of the variable frequency controller is usually 4-6 kHz, the noise interference caused by the switching power devices in this frequency range is exactly in the high-frequency sensitive area of ​​GFCI operation. In this way, combined with the interference of the power grid, the GFCI can easily be falsely triggered, causing tripping, resulting in the variable frequency refrigerator or freezer in this frequency range not being able to be used normally. However, for the frequency range above 7 kHz, the trigger current will become larger and larger, that is, it is insensitive. Increasing the PWM carrier frequency of the variable frequency controller can effectively prevent tripping. Therefore, when the leakage current is greater than the current threshold, the carrier frequency of the variable frequency controller needs to be increased. At this time, the carrier frequency increase amount of the variable frequency controller is determined based on the current difference. The carrier frequency increase amount indicates how much the frequency needs to be increased. The larger the current difference, the higher the carrier frequency increase amount.

[0221] In some embodiments, the current threshold can be pre-set, such as determined in a laboratory based on refrigerator operating parameters (gear position, compressor frequency, ambient temperature, etc.). After obtaining the leakage current, the real-time operating parameters of the refrigerator are also obtained and then matched with pre-stored data to obtain a current threshold that matches the current refrigerator operating parameters. This matched current threshold is then compared with the leakage current.

[0222] In some embodiments, the adjusted carrier frequency of the variable frequency controller is in the range of 7-20 kHz. A carrier frequency of the variable frequency controller in the range of 7-20 kHz can solve the CFCI tripping problem.

[0223] For example, a GFCI is very sensitive to high frequencies of 4-6 kHz, but for frequencies above 7 kHz, the trigger current becomes increasingly larger, meaning it becomes less sensitive. Increasing the PWM carrier frequency of the frequency converter controller can effectively prevent tripping. Using an 8-9 kHz carrier frequency for the frequency converter controller in this application can partially resolve the tripping issue, with 10-20 kHz providing even better results. For 8-9 kHz power devices, IGBTs can be used, while for 10-20 kHz power devices, MOSFETs or GaN FETs can be used.

[0224] In some embodiments, the variable frequency controller is provided with a PID controller 15. Referring again to the connection diagram of the variable frequency controller 8 and the compressor 1 shown in FIG15 , the variable frequency controller 8 is provided with a main controller 14 and a PID controller 15. The main controller 14 is configured to obtain the leakage current sent by the sampling circuit and also to collect the operating parameters of the compressor. Based on these operating parameters, the operating status of the compressor 1 can be monitored, providing timely warnings when a compressor failure occurs. The main controller 14 can also control the startup and shutdown of the compressor 1.

[0225] In some embodiments, after adjusting the carrier frequency of the variable frequency controller according to the carrier frequency boost amount, the method includes: using the target operating frequency of the compressor as the input of the PID controller 22, and outputting a PWM carrier frequency through PID regulation.

[0226] For example, see Figure 22, which is a workflow diagram of the frequency conversion controller in the refrigerator provided in other embodiments of the present application. After executing step S215, the frequency conversion controller is also configured to execute step S216: using the target operating frequency of the compressor as the input of the PID controller, and outputting the PWM carrier frequency through PID adjustment.

[0227] The actual operating frequency of the frequency conversion controller is adjusted through the PID link (the actual operating frequency collected in real time is compared with the target operating frequency, and the PWM carrier frequency is dynamically adjusted through the PID algorithm), and the appropriate PWM carrier frequency is output, and then the motor of the compressor is driven based on this PWM carrier frequency.

[0228] Referring to Figure 23, Figure 23 is a schematic diagram illustrating the connections between a sampling circuit, a frequency conversion controller, and a compressor provided in some embodiments of the present application. The sampling circuit 16 includes an operational amplifier U1 and a current transformer U2. One end of the current transformer U2 is connected to the power input terminals (L, N), and the other end is connected to the positive and negative input terminals of the operational amplifier U1, respectively. The output of the operational amplifier U1 is connected to the frequency conversion controller 8.

[0229] For example, the combined current on the L and N lines, as the load operates and external interference signals overlap, will form power frequency and high-frequency bias currents (this current is equal in magnitude to the leakage current on the ground line, but opposite in direction). This current is collected by the current transformer U2 and input into the operational amplifier U1 for signal processing. The specific working process of the operational amplifier U1 can be referred to in the prior art and will not be described in detail in this application. The data processed by the operational amplifier U1 is input into the main controller 14, which can perform a Fourier operation on this data to obtain the equivalent current of each frequency band. This equivalent current is the leakage current. By comparing the leakage current with the current threshold, the variable frequency carrier frequency and load size are adjusted to meet the GFCI's non-tripping requirement.

[0230] Referring to FIG. 24 , FIG. 24 is a circuit diagram of a sampling circuit 16 provided in some embodiments of the present application. The sampling circuit 16 further includes a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, and a sixteenth resistor R16. The positive input terminal OA0_P of the operational amplifier U1 is connected to the current transformer U2 (and then to the L line) via the thirteenth resistor R13 and the fifteenth resistor R15, while the negative input terminal OA0_L of the operational amplifier U1 is connected to the current transformer U2 (and then to the N line) via the fourteenth resistor R14 and the sixteenth resistor R16.

[0231] Exemplarily, U1 is an operational amplifier, which is the core component of the sampling unit; U2 is a current transformer, which samples the composite current of L (live wire) and N (neutral wire); the thirteenth resistor R13 and the fifteenth resistor R15 constitute the positive end input of the operational amplifier circuit, and the fourteenth resistor R14 and the sixteenth resistor R16 constitute the negative end input of the operational amplifier circuit.

[0232] In some embodiments, the sampling circuit 16 further includes a third capacitor C3 and a fourth capacitor C4. The first end of the third capacitor C3 is connected to the thirteenth resistor R13 and the fifteenth resistor R15, respectively, and the second end of the third capacitor C3 is connected to the fourteenth resistor R14 and the sixteenth resistor R16, respectively. The first end of the fourth capacitor C4 is connected to the fourteenth resistor R14 and the sixteenth resistor R16, respectively, and the second end of the fourth capacitor C4 is grounded. Exemplarily, the third capacitor C3 and the fourth capacitor C4 are filter capacitors that perform a filtering function, filtering the currents of the L and N lines collected by the current transformer U2 and then inputting them into the operational amplifier U1.

[0233] In some embodiments, the sampling circuit 16 further includes a seventeenth resistor R17. A first end of the seventeenth resistor R17 is connected to a power supply terminal Vref, and a second end of the seventeenth resistor R17 is connected to a positive input terminal OA0_P of the operational amplifier U1. Exemplarily, the power supply terminal Vref is used to input a DC voltage to the positive input terminal OA0_P of the operational amplifier U1, and R17 is a reference terminal resistor.

[0234] In some embodiments, the sampling circuit 16 further includes an eighteenth resistor R18 and a fifth capacitor C5. A first end of the eighteenth resistor R18 is connected to the negative input terminal OA0_N of the operational amplifier U1, and a second end of the eighteenth resistor R18 is connected to the output terminal OA0_OUT of the operational amplifier U1. A first end of the third capacitor C3 is connected to the negative input terminal OA0_N of the operational amplifier U1, and a second end of the fifth capacitor C5 is connected to the output terminal OA0_OUT of the operational amplifier U1. Exemplarily, the eighteenth resistor R18 and the fifth capacitor C5 form a feedback loop.

[0235] In some embodiments, the sampling circuit 16 further includes a nineteenth resistor R19 and a sixth capacitor C6. A first end of the nineteenth resistor R19 is connected to the output terminal of the operational amplifier U1, and a second end of the nineteenth resistor R19 is connected to the frequency conversion controller 8. A first end of the sixth capacitor C6 is connected to the second end of the nineteenth resistor R19, and a second end of the sixth capacitor C6 is grounded. Exemplarily, the amplified output signal output by the operational amplifier U1 is filtered by the nineteenth resistor R19 and the sixth capacitor C6, then output from the output terminal OUT_MCU of the sampling circuit and finally input to the main controller 14 for processing.

[0236] In some embodiments of the present application, a refrigerator is provided with a sampling circuit for collecting leakage current from the power input terminal. The frequency conversion controller obtains the leakage current collected by the sampling circuit in real time. When the leakage current value is greater than a preset current threshold, the current difference between the leakage current and the current threshold is calculated. The carrier frequency increase amount of the frequency conversion controller is then determined based on the current difference, and the carrier frequency of the frequency conversion controller is adjusted based on the carrier frequency increase amount. In this way, the carrier frequency (switching power device frequency) of the frequency conversion controller can be increased, effectively adjusting the output carrier frequency of the frequency conversion controller to achieve compatibility with GFCI. Increasing the PWM carrier frequency of the frequency conversion controller can effectively prevent tripping.

[0237] Referring to FIG. 25 , FIG. 25 is a flow chart of a refrigerator control method provided in some embodiments of the present application. The refrigerator includes a sampling circuit for sampling leakage current at a power input terminal of the refrigerator. The method includes:

[0238] S251, obtaining the leakage current collected by the sampling circuit;

[0239] S252: When the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold;

[0240] S253: Determine a carrier frequency increase amount of the frequency conversion controller in the refrigerator according to the current difference, and adjust the carrier frequency of the frequency conversion controller according to the carrier frequency increase amount.

[0241] In some embodiments, a PID controller is provided in the frequency conversion controller. After adjusting the carrier frequency of the frequency conversion controller according to the carrier frequency increase amount, the method includes: using the target operating frequency of the compressor as the input of the PID controller, and outputting a PWM carrier frequency through PID regulation.

[0242] In some embodiments, the adjusted carrier frequency of the variable frequency controller is greater than or equal to 7 kHz.

[0243] In some embodiments, the sampling circuit includes an operational amplifier and a current transformer. One end of the current transformer is provided at the power input end, and the other end is connected to the positive input end and the negative input end of the operational amplifier, respectively. The output end of the operational amplifier is connected to the frequency conversion controller.

[0244] In some embodiments, the sampling circuit further includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a sixteenth resistor. The positive input terminal of the operational amplifier is connected to the current transformer through the thirteenth resistor and the fifteenth resistor, and the negative input terminal of the operational amplifier is connected to the current transformer through the fourteenth resistor and the sixteenth resistor.

[0245] In some embodiments, the sampling circuit further includes a third capacitor and a fourth capacitor. A first end of the third capacitor is connected to the thirteenth resistor and the fifteenth resistor, respectively, and a second end of the third capacitor is connected to the fourteenth resistor and the sixteenth resistor, respectively; a first end of the fourth capacitor is connected to the fourteenth resistor and the sixteenth resistor, respectively, and a second end of the fourth capacitor is grounded.

[0246] In some embodiments, the sampling circuit further includes a seventeenth resistor, wherein a first end of the seventeenth resistor is connected to a power supply terminal, and a second end of the seventeenth resistor is connected to a positive input terminal of the operational amplifier.

[0247] In some embodiments, the sampling circuit further includes an eighteenth resistor and a fifth capacitor C5. A first end of the eighteenth resistor is connected to the negative input terminal of the operational amplifier, and a second end of the eighteenth resistor is connected to the output terminal of the operational amplifier; a first end of the fifth capacitor is connected to the negative input terminal of the operational amplifier, and a second end of the fifth capacitor is connected to the output terminal of the operational amplifier.

[0248] In some embodiments, the sampling circuit further includes a nineteenth resistor and a sixth capacitor. A first end of the nineteenth resistor is connected to the output end of the operational amplifier, and a second end of the nineteenth resistor is connected to the frequency conversion controller; a first end of the sixth capacitor is connected to the second end of the nineteenth resistor, and a second end of the sixth capacitor is grounded.

[0249] It is worth noting that the detailed working process of the refrigerator control method described in this embodiment can refer to the working process of the frequency conversion controller in the refrigerator described in the above embodiment, and will not be repeated here.

[0250] In some embodiments of the present application, a refrigerator control method is disclosed. A sampling circuit for collecting leakage current from a power input terminal is provided in the refrigerator. A frequency conversion controller acquires the leakage current collected by the sampling circuit in real time. When the leakage current is greater than a preset current threshold, the current difference between the leakage current and the current threshold is calculated. The frequency conversion controller's carrier frequency increase is then determined based on the current difference, and the frequency conversion controller's carrier frequency is adjusted based on the carrier frequency increase. This increases the frequency conversion controller's carrier frequency (the switching power device frequency), effectively regulating the frequency conversion controller's output carrier frequency to achieve compatibility with GFCIs. This increases the frequency conversion controller's PWM carrier frequency, effectively preventing tripping.

[0251] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0252] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A refrigerator comprising: A box body, having at least one storage compartment therein; A box door is provided at the opening of the storage chamber; A compressor is arranged in the box; The variable frequency controller is configured as: Controlling the compressor to run to a target speed gear; When the compressor is at the target speed gear, gradually adjust the carrier frequency of the frequency conversion controller to the next carrier frequency gear until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, stop the gradual adjustment, and adjust the carrier frequency of the frequency conversion controller to the previous carrier frequency gear; The current energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the current carrier frequency gear; the previous energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the previous carrier frequency gear.

2. The refrigerator according to claim 1, wherein The refrigerator further comprises: A voltage acquisition device, connected to the frequency conversion controller and configured to acquire a current input voltage of the frequency conversion controller; A current acquisition device, connected to the frequency conversion controller and configured to acquire the current output current of the frequency conversion controller; The frequency conversion controller is further configured to: Acquiring the current input voltage of the frequency conversion controller collected by the voltage collection device; Acquiring the current output current of the frequency conversion controller collected by the current collection device; The current energy consumption of the frequency conversion controller is calculated according to the current input voltage and the current output current.

3. The refrigerator according to claim 2, wherein: The frequency conversion controller is further configured to: The current energy consumption of the frequency converter is calculated according to the following formula: Q=∫U*Idt+K1*f+K2*I+Q0 Among them, U is the current input voltage of the frequency converter, I is the current output current of the frequency converter, K1 is the preset switching loss coefficient, K2 is the preset operating power consumption coefficient, f is the carrier frequency when the frequency converter is in the current carrier frequency gear at the target speed gear, and Q0 is the preset static power consumption of the frequency converter.

4. The refrigerator according to claim 2 or 3, wherein: The current acquisition device includes a current amplifying circuit, a first resistor, a bias circuit, a second resistor and a first capacitor: a current amplifying circuit, wherein a first input terminal of the current amplifying circuit is configured to receive a current of the power device, a second input terminal of the current amplifying circuit is respectively connected to a first terminal of the first resistor and a first terminal of the bias circuit, and an output terminal of the current amplifying circuit is respectively connected to a second terminal of the bias circuit and a first terminal of the second resistor; The second end of the first resistor is grounded; The second end of the second resistor is connected to the first end of the first capacitor; The first end of the first capacitor is also connected to the first sampling pin of the frequency conversion controller, and the second end of the first capacitor is grounded.

5. The refrigerator according to any one of claims 2 to 4, wherein: The voltage acquisition device comprises: a resistance unit, wherein a first end of the resistance unit is connected to a voltage, and a second end of the resistance unit is connected to a first end of a ninth resistor; the ninth resistor, wherein a first end of the ninth resistor is further connected to the first end of the second capacitor, and a second end of the ninth resistor is grounded; The second capacitor has a first end connected to the second sampling pin of the frequency conversion controller, and a second end connected to the ground.

6. A method for controlling a refrigerator, the refrigerator comprising at least a compressor and a frequency conversion controller, the method comprising: Controlling the compressor to run to a target speed gear; When the compressor is at the target speed gear, gradually adjust the carrier frequency of the frequency conversion controller to the next carrier frequency gear until the current energy consumption of the frequency conversion controller is greater than or equal to the previous energy consumption of the frequency conversion controller, stop the gradual adjustment, and adjust the carrier frequency of the frequency conversion controller to the previous carrier frequency gear; The current energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the current carrier frequency gear; the previous energy consumption of the frequency conversion controller is the energy consumption when the frequency conversion controller is in the previous carrier frequency gear.

7. The refrigerator control method according to claim 6, wherein: The refrigerator further comprises: a voltage acquisition device, connected to the frequency conversion controller and configured to acquire the current input voltage of the frequency conversion controller; a current acquisition device, connected to the frequency conversion controller and configured to acquire the current output current of the frequency conversion controller; The refrigerator control method further includes: Acquiring the current input voltage collected by the voltage collection device; Acquiring the current output current collected by the current collection device; The current energy consumption of the frequency conversion controller is calculated according to the current input voltage and the current output current.

8. The refrigerator control method according to claim 7, wherein: The refrigerator control method further includes: The current energy consumption of the frequency converter is calculated according to the following formula: Q=∫U*Idt+K1*f+K2*I+Q0 Among them, U is the current input voltage of the frequency converter, I is the current output current of the frequency converter, K1 is the preset switching loss coefficient, K2 is the preset operating power consumption coefficient, f is the carrier frequency when the frequency converter is in the current carrier frequency gear at the target speed gear, and Q0 is the preset static power consumption of the frequency converter.

9. A refrigerator comprising: a box body, in which at least one storage chamber is formed; A box door is provided at the opening of the storage chamber; A compressor is arranged in the box; A frequency conversion controller is provided in the box, wherein a PID controller is provided in the frequency conversion controller, and the frequency conversion controller is configured as follows: Obtaining electrical parameters of the motor in the frequency conversion controller, and calculating output power based on the electrical parameters and preset frequency conversion characteristic parameters; When the output power does not match the preset target power, the output power is used as the input of the PID controller, and a reference speed is output to the compressor through PID regulation, so that the compressor operates at the reference speed.

10. The refrigerator according to claim 9, wherein The electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value.

11. The refrigerator according to claim 10, wherein: The calculating the output power according to the electrical parameters and the preset frequency conversion characteristic parameters includes: Calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power; Calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power; The output power is obtained by calculating the product of the power sum of the q-axis power and the d-axis power and the frequency conversion characteristic parameter.

12. The refrigerator according to claim 9, wherein The frequency conversion controller is further configured to: calculating the back electromotive force of the motor; When the back electromotive force generated by the motor is greater than the bus voltage, the motor is subjected to flux weakening control.

13. The refrigerator according to claim 9, wherein The variable frequency controller is further provided with a three-phase bridge, which is respectively connected to the PID controller and the compressor. The three-phase bridge includes a bridge circuit composed of a plurality of insulated gate bipolar transistors.

14. A refrigerator control method, applied to a refrigerator, wherein the refrigerator includes a frequency conversion controller, a compressor, and a PID controller, the method comprising: Obtaining electrical parameters of the motor in the frequency conversion controller, and calculating the output power based on the electrical parameters and preset frequency conversion characteristic parameters; When the output power does not match the preset target power, the output power is used as the input of the PID controller, and a reference speed is output to the compressor through PID regulation, so that the compressor operates at the reference speed.

15. The refrigerator control method according to claim 14, wherein: The electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value.

16. The refrigerator control method according to claim 15, wherein: The calculating the output power according to the electrical parameters and the preset frequency conversion characteristic parameters includes: Calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power; Calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power; The output power is obtained by calculating the product of the power sum of the q-axis power and the d-axis power and the frequency conversion characteristic parameter.

17. The refrigerator control method according to claim 14, wherein: The method further comprises: calculating the back electromotive force of the motor; When the back electromotive force generated by the motor is greater than the bus voltage, the motor is subjected to flux weakening control.

18. A refrigerator comprising: a box body, in which at least one storage chamber is formed; A box door is provided at the opening of the storage chamber; A compressor is arranged in the box; a sampling circuit, disposed in the box, configured to sample leakage current at a power input terminal of the refrigerator; A frequency conversion controller is provided in the box, and the frequency conversion controller is configured as follows: Obtaining the leakage current collected by the sampling circuit; When the value of the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold; The carrier frequency increase amount of the frequency conversion controller is determined according to the current difference, and the carrier frequency of the frequency conversion controller is adjusted according to the carrier frequency increase amount.

19. The refrigerator according to claim 18, wherein The frequency conversion controller is provided with a PID controller. After adjusting the carrier frequency of the frequency conversion controller according to the carrier frequency boost amount, the frequency conversion controller is further configured as follows: The target operating frequency of the compressor is used as the input of the PID controller, and the PWM carrier frequency is output through PID regulation.

20. The refrigerator according to claim 18, wherein The adjusted carrier frequency range of the frequency conversion control is 7-20KHz.

21. The refrigerator according to claim 18, wherein The sampling circuit includes an operational amplifier and a current transformer; wherein one end of the current transformer is arranged at the power input end, and the other end is respectively connected to the positive input end and the negative input end of the operational amplifier, and the output end of the operational amplifier is connected to the frequency conversion controller.

22. The refrigerator according to claim 21, wherein The sampling circuit further includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a sixteenth resistor; wherein the positive input terminal of the operational amplifier is connected to the current transformer through the thirteenth resistor and the fifteenth resistor, and the negative input terminal of the operational amplifier is connected to the current transformer through the fourteenth resistor and the sixteenth resistor.

23. The refrigerator according to claim 22, wherein The sampling circuit further includes a third capacitor and a fourth capacitor; wherein a first end of the third capacitor is connected to the thirteenth resistor and the fifteenth resistor, respectively, and a second end of the third capacitor is connected to the fourteenth resistor and the sixteenth resistor, respectively; a first end of the fourth capacitor is connected to the fourteenth resistor and the sixteenth resistor, respectively, and a second end of the fourth capacitor is grounded.

24. The refrigerator according to claim 21, wherein The sampling circuit further includes a seventeenth resistor; wherein a first end of the seventeenth resistor is connected to a power supply end, and a second end of the seventeenth resistor is connected to a positive input end of the operational amplifier.

25. The refrigerator according to claim 21, wherein The sampling circuit also includes an eighteenth resistor and a fifth capacitor; wherein, a first end of the eighteenth resistor is connected to the negative input terminal of the operational amplifier, and a second end of the eighteenth resistor is connected to the output terminal of the operational amplifier; a first end of the fifth capacitor is connected to the negative input terminal of the operational amplifier, and a second end of the fifth capacitor is connected to the output terminal of the operational amplifier.

26. The refrigerator according to claim 21, wherein The sampling circuit also includes a nineteenth resistor and a sixth capacitor; wherein a first end of the nineteenth resistor is connected to the output end of the operational amplifier, and a second end of the nineteenth resistor is connected to the frequency conversion controller; a first end of the sixth capacitor is connected to the second end of the nineteenth resistor, and a second end of the sixth capacitor is grounded.

27. A refrigerator control method, applied to a refrigerator, the refrigerator comprising a sampling circuit configured to sample leakage current at a power input terminal of the refrigerator, the method comprising: Obtaining a leakage current at a power input terminal of the refrigerator collected by the sampling circuit; When the value of the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold; A carrier frequency increase amount of a frequency conversion controller in the refrigerator is determined according to the current difference, and the carrier frequency of the frequency conversion controller is adjusted according to the carrier frequency increase amount.

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