Refrigerator and control method thereof

Abstract

The invention discloses a refrigerator and a control method thereof.The refrigerator is internally provided with a sampling circuit used for collecting the leakage current of a power input end, a frequency conversion controller obtains the leakage current collected by the sampling circuit in real time, when the leakage current is larger than a preset current threshold value, the current difference value between the leakage current and the current threshold value is calculated, and the current difference value is calculated according to the current difference value. And then determining the frequency load increase amount of the variable frequency controller according to the current difference value, and obtaining the target operation frequency of the variable frequency controller according to the frequency load increase amount. By adopting the embodiment of the invention, the carrier frequency (switching power device frequency) of the variable-frequency controller can be improved, the output carrier frequency of the variable-frequency controller can be effectively adjusted, compatible use with GFCI is achieved, the PWM carrier frequency of the variable-frequency controller is improved, and the tripping phenomenon can be effectively restrained.

Description

Technical Field

[0001] The present invention relates to the field of refrigerators, and in particular to a refrigerator and a control method thereof. Background Art

[0002] 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 powered by a GFCI (Ground Fault Circuit Interrupter)-equipped outlet, the inverter refrigerator may trip due to non-power-frequency leakage current. The carrier frequency of the inverter controller currently operates between 4 and 6 kHz. The noise interference caused by the switching power devices in this frequency range falls within the GFCI's sensitive high-frequency operating range. Combined with grid interference, this can easily cause the GFCI to trip, resulting in malfunction of the inverter refrigerator or freezer in this frequency range, leading to customer complaints or product returns. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a refrigerator and a control method thereof, which 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.

[0004] To achieve the above object, an embodiment of the present invention provides a refrigerator, comprising:

[0005] a box body, in which at least one storage chamber is formed;

[0006] A door is provided at the opening of the storage chamber and is used to open and close the storage chamber;

[0007] a compressor, disposed within the housing, for providing power for a refrigeration cycle of the refrigerator;

[0008] A sampling circuit is provided in the box and is used to sample the leakage current of the power input terminal of the refrigerator;

[0009] A frequency conversion controller is provided in the box, and the frequency conversion controller is configured as follows:

[0010] Obtaining the leakage current collected by the sampling circuit;

[0011] When the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold;

[0012] The frequency load increase amount of the frequency conversion controller is determined according to the current difference, and the target operating frequency of the frequency conversion controller is obtained according to the frequency load increase amount.

[0013] As an improvement to the above solution, the frequency conversion controller is provided with a PID module. After obtaining the target operating frequency of the frequency conversion controller according to the frequency load increase, the frequency conversion controller is further configured as follows:

[0014] The target operating frequency is used as the input of the PID module, and the PWM carrier frequency is output through PID regulation.

[0015] As an improvement to the above solution, the target operating frequency is greater than or equal to 7 KHz and less than or equal to 20 KHz.

[0016] As an improvement to the above scheme, 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.

[0017] As an improvement to the above solution, the sampling circuit further includes a first resistor, a second resistor, a third resistor and a fourth resistor; wherein the positive input terminal of the operational amplifier is connected to the current transformer through the first resistor and the third resistor, and the negative input terminal of the operational amplifier is connected to the current transformer through the second resistor and the fourth resistor.

[0018] As an improvement to the above solution, the sampling circuit further includes a first capacitor and a second capacitor; wherein, the first end of the first capacitor is respectively connected to the first resistor and the third resistor, and the second end of the first capacitor is respectively connected to the second resistor and the fourth resistor; the first end of the second capacitor is respectively connected to the second resistor and the fourth resistor, and the second end of the second capacitor is grounded.

[0019] As an improvement to the above solution, the sampling circuit further includes a fifth resistor; wherein a first end of the fifth resistor is connected to a power supply end, and a second end of the fifth resistor is connected to a positive input end of the operational amplifier.

[0020] As an improvement to the above solution, the sampling circuit further includes a sixth resistor and a third capacitor; wherein, the first end of the sixth resistor is connected to the negative input terminal of the operational amplifier, and the second end of the sixth resistor is connected to the output terminal of the operational amplifier; the first end of the third capacitor is connected to the negative input terminal of the operational amplifier, and the second end of the third capacitor is connected to the output terminal of the operational amplifier.

[0021] As an improvement to the above solution, the sampling circuit further includes a seventh resistor and a fourth capacitor; wherein, the first end of the seventh resistor is connected to the output end of the operational amplifier, and the second end of the seventh resistor is connected to the frequency conversion controller; the first end of the fourth capacitor is connected to the second end of the seventh resistor, and the second end of the fourth capacitor is grounded.

[0022] To achieve the above-mentioned object, an embodiment of the present invention further provides a refrigerator control method, wherein the refrigerator includes a sampling circuit for sampling a leakage current at a power input terminal of the refrigerator. The method includes:

[0023] Obtaining the leakage current collected by the sampling circuit;

[0024] When the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold;

[0025] The frequency load increase amount of the frequency conversion controller is determined according to the current difference, and the target operating frequency of the frequency conversion controller is obtained according to the frequency load increase amount.

[0026] Compared to the prior art, the refrigerator and control method disclosed in the present invention are equipped 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 is greater than a preset current threshold, the current difference between the leakage current and the current threshold is calculated. The frequency-load increase amount of the frequency conversion controller is then determined based on the current difference, and the target operating frequency of the frequency conversion controller is obtained based on the frequency-load increase amount. By adopting the embodiment of the present invention, the carrier frequency (switching power device frequency) of the frequency conversion controller can be increased, and the output carrier frequency of the frequency conversion controller can be effectively adjusted to achieve compatibility with GFCI. The PWM carrier frequency of the frequency conversion controller is increased, which can effectively prevent tripping. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 1 is a schematic diagram of the external structure of a refrigerator provided by an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the internal structure of a refrigerator provided by an embodiment of the present invention;

[0029] Figure 3 1 is a schematic structural diagram of a refrigeration system in a refrigerator provided by an embodiment of the present invention;

[0030] Figure 4 1 is a schematic structural diagram of a compressor cabin provided by an embodiment of the present invention;

[0031] Figure 5 This is a first working flow diagram of a frequency conversion controller in a refrigerator provided by an embodiment of the present invention;

[0032] Figure 6 Schematic diagram of a PID control link provided by an embodiment of the present invention;

[0033] Figure 7 This is a second working flow diagram of the frequency conversion controller in the refrigerator provided by an embodiment of the present invention;

[0034] Figure 8 This is a connection diagram of a sampling circuit, a frequency conversion controller, and a compressor provided by an embodiment of the present invention;

[0035] Figure 9 is a circuit diagram of a sampling circuit provided by an embodiment of the present invention;

[0036] Figure 10 This is a flow chart of a refrigerator control method provided by an embodiment of the present invention.

[0037] Among them, 100, refrigerator; 10, frequency conversion controller; 10A, compressor cabin; 1, compressor; 2, evaporator; 3, capillary tube; 4, condenser; 5, bottom cooling fan; 6, evaporating dish. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do 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.

[0040] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features specified as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0041] 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 broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication 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.

[0042] See also Figure 1 , Figure 1 The figure below is a schematic diagram of the external structure of a refrigerator 100 provided in an embodiment of the present invention. The refrigerator 100 of this embodiment is approximately rectangular in shape and includes a housing defining a storage space and multiple doors disposed at the housing opening. The doors include a door shell located on the outside of the housing, a door liner located on the inside of the housing, an upper end cover, a lower end cover, and an insulation layer located between the door shell, the door liner, the upper end cover, and the lower end cover. Typically, the insulation layer is filled with foam. The housing is provided with a chamber, which includes a component storage cavity for accommodating refrigerator components, such as a compressor compartment, and storage space for food and the like.

[0043] See also Figure 2 , Figure 2 This is a schematic diagram of the internal structure of a refrigerator provided by an embodiment of the present invention. The storage space can be divided into multiple storage rooms. The storage rooms can be configured as refrigerators and freezers according to different uses. They can also include variable temperature rooms, vacuum drawers, moisturizing drawers, etc. Each storage room corresponds to one or more doors, such as Figure 2 The upper storage compartment has a double-door body. The door can be pivotally mounted at the opening of the refrigerator body and can also be opened in a drawer-like manner to achieve drawer-style storage. The refrigerator door is equipped with a display screen for displaying prompt information and receiving user touch operations.

[0044] See also Figure 3 , Figure 3The structural diagram of the refrigeration system in the refrigerator provided by the embodiment of the present invention, the refrigeration system includes a compressor 1, an evaporator 2, a drying filter (not shown in the figure), a capillary tube 3, a condenser 4 and a gas-liquid separator (not shown in the figure). The working process of the refrigeration system includes a compression process, a condensation process, a throttling process and an evaporation process. The compression process is: plug in the power cord of the refrigerator, when the contacts of the thermostat are connected, the compressor 1 starts to work, the low-temperature, low-pressure refrigerant is sucked into the compressor 1, and is compressed into a high-temperature, high-pressure superheated gas in the cylinder of the compressor 1 and then discharged into the condenser 4; the condensation process is: the high-temperature, high-pressure refrigerant gas dissipates heat through the condenser 4, the temperature continues to drop, and is gradually cooled to a saturated vapor of normal temperature and high pressure, and is further cooled to a saturated liquid, and the temperature no longer drops. The temperature at this time is called the condensation temperature, and the pressure of the refrigerant remains almost unchanged during the entire condensation process; The flow process is as follows: the saturated refrigerant liquid after condensation is filtered out of moisture and impurities by the drying filter and then flows into the capillary tube 3, through which the refrigerant is throttled and depressurized to become wet steam 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 2, which not only reduces the temperature of the evaporator 2 and its surroundings, but also turns the refrigerant into a low-temperature and low-pressure gas. The refrigerant coming out of the evaporator 2 passes through the gas-liquid separator and returns to the compressor 1 again, repeating the above process to transfer the heat in the refrigerator to the air outside the box, thereby achieving the purpose of refrigeration.

[0045] See also Figure 4 , Figure 4The diagram is a schematic diagram of the structure of a compressor compartment 10A according to an embodiment of the present invention. The compressor compartment 10A is equipped with a compressor 1, a condenser 4, a bottom cooling fan 5, and an evaporation dish 6. The evaporation dish 6 is used to receive defrost water. Specifically, the evaporation dish 6 receives defrost water from the freezer compartment and / or from the evaporator 2 during defrost. The evaporation dish 6 is fixed to the bottom wall of the compressor compartment 10A and is a box-like structure with an open top. The evaporation dish 6 comprises a horizontal bottom plate and side panels extending upward from the edges of the bottom plate. The side panels are arranged around the perimeter and interlock with each other, and the bottom plate is enclosed by the edges of the side panels, forming a box-like structure with an open top. The condenser 4 is arranged vertically, with its top end abutting the top surface of the compressor compartment 10A. This ensures that the condenser 4 can be installed within the compressor compartment 10A while minimizing the height of the compressor compartment 10A and thus increasing the storage compartment volume. The condenser 4 and the compressor 1 are spaced apart in the left-right direction. The bottom plate of the evaporating dish 6 is formed with protruding fixing posts, and the bottom end of the condenser 4 is fixed to the fixing posts directly or via connectors, so that the condenser 4 is fixed within the evaporating dish 6 and the bottom end of the condenser 4 is higher than the level of the defrost water in the evaporating dish 6. The refrigerator 100 is also equipped with a bottom cooling fan 5 for heat dissipation. A through hole (not shown) is provided on the side of the compressor compartment 10A facing the bottom cooling fan 5. The refrigerator 100 is provided with an exhaust vent for the outlet of the bottom cooling fan 5. In this embodiment, the bottom cooling fan 5 is a centrifugal fan. The left and right sides of the centrifugal fan are respectively attached to the compressor compartment 10A. The centrifugal fan inlet is provided in the through hole of the compressor compartment 10A, so that air in the compressor compartment 10A is discharged from the compressor compartment 10A through the centrifugal fan inlet.

[0046] Specifically, the frequency conversion controller of the refrigerator is configured to: obtain the leakage current collected by the 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 the frequency load increase of the frequency conversion controller based on the current difference, and obtain the target operating frequency of the frequency conversion controller based on the frequency load increase.

[0047] For example, see Figure 5 , Figure 5This is a first workflow diagram of a frequency conversion controller in a refrigerator provided by an embodiment of the present invention, wherein the frequency conversion controller is configured to execute steps S11 to S15. After the refrigerator is started, the frequency conversion controller begins to obtain leakage current from the power input terminal, which is collected by a sampling circuit. The power input terminal is the L (live) and N (neutral) wires of the power input. After obtaining the leakage current, the leakage current is compared with a preset current threshold. If the leakage current is less than or equal to the current threshold, it indicates that the leakage current is very low or non-existent, and the GFCI will not trip or the risk of tripping is very low. At this time, the frequency conversion controller maintains the original operating mode. If the leakage current is greater than the current threshold, it indicates a high leakage current and a high risk of GFCI tripping. The difference between the leakage current and the current threshold is calculated, and the compressor's operating frequency is then determined based on the current difference. As can be understood, since the current carrier frequency of the variable frequency controller is currently normally between 4 and 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, causing it to trip, rendering the variable frequency refrigerator or freezer in this frequency range inoperable. However, for frequencies above 7 kHz, the triggering current increases, making it less sensitive. 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 compressor's operating frequency needs to be increased. The frequency carrier boost amount of the variable frequency controller is determined based on the current difference. The frequency carrier boost amount indicates the amount by which the frequency needs to be increased. A larger current difference results in a higher frequency carrier boost amount, corresponding to a higher target operating frequency.

[0048] Furthermore, the current threshold can be pre-set, such as determined in a laboratory based on refrigerator operating parameters (gear, compressor frequency, ambient temperature, etc.). After obtaining the leakage current, the real-time operating parameters of the refrigerator are obtained at the same time, and then matched with the pre-stored data to obtain a current threshold that meets the current refrigerator operating parameters, and then the matched current threshold is compared with the leakage current.

[0049] Specifically, the target operating frequency is greater than or equal to 7 KHz and less than or equal to 20 KHz.

[0050] For example, a GFCI is very sensitive to high frequencies of 4-6 kHz, but at frequencies above 7 kHz, the trigger current increases, becoming less sensitive. Increasing the PWM carrier frequency of the variable frequency controller can effectively prevent tripping. The present invention can partially address the tripping issue by using 8-9 kHz, with even greater results at 10-20 kHz. For 8-9 kHz power devices, IGBTs can be used, while for 10-20 kHz power devices, MOSFETs or GaN FETs can be used.

[0051] Specifically, the frequency conversion controller is provided with a PID module, see Figure 6 , Figure 6 This is a connection diagram of the frequency conversion controller 20 and the compressor 1 provided in an embodiment of the present invention. The frequency conversion controller 20 is provided with a main control module MCU21 and a PID module 22. The MCU21 is used to collect the leakage current sent by the sampling circuit and can also collect the operating parameters of the compressor. According to these operating parameters, the operating status of the compressor 1 can be monitored, and timely warning can be given when the compressor fails. In addition, the MCU21 can control the start and stop of the compressor 1.

[0052] Specifically, after obtaining the target operating frequency of the frequency conversion controller according to the frequency carrier boost amount, the method includes: using the target operating frequency as the input of the PID module 22, and outputting a PWM carrier frequency through PID regulation.

[0053] For example, see Figure 7 , Figure 7 This is a second workflow diagram of the variable frequency controller for a refrigerator provided by an embodiment of the present invention. After executing step S15, the variable frequency controller is further configured to execute step S16. The actual operating frequency of the variable frequency control is adjusted through a PID process (the actual operating frequency acquired in real time is compared with the target operating frequency), an appropriate PWM carrier frequency is output, and the compressor motor is then driven based on this PWM carrier frequency.

[0054] See also Figure 8 , Figure 8 This is a connection diagram of a sampling circuit, a frequency conversion controller, and a compressor provided in an embodiment of the present invention. The sampling circuit includes an operational amplifier UI and a current transformer U2; wherein, one end of the current transformer U2 is provided at the power input end (L, N), and the other end is respectively connected to the positive input end and the negative input end of the operational amplifier U1, and the output end of the operational amplifier U1 is connected to the frequency conversion controller 20.

[0055] 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 the prior art and will not be described in detail in this invention. The data processed by the operational amplifier U1 is input into the MCU21, 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.

[0056] See also Figure 9 , Figure 9 is a circuit diagram of a sampling circuit 10 provided in an embodiment of the present invention. The sampling circuit 10 further includes a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The positive input terminal OA0_P of the operational amplifier U1 is connected to the current transformer U2 (further connected to the L line) through the first resistor R1 and the third resistor R3, and the negative input terminal OA0_L of the operational amplifier U1 is connected to the current transformer U2 (further connected to the N line) through the second resistor R2 and the fourth resistor R4.

[0057] 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 first resistor R1 and the third resistor R3 constitute the positive input of the operational amplifier circuit, and the second resistor R2 and the fourth resistor R4 constitute the negative input of the operational amplifier circuit.

[0058] Specifically, the sampling circuit 10 further includes a first capacitor C1 and a second capacitor C2; wherein the first end of the first capacitor C1 is connected to the first resistor R1 and the third resistor R3, respectively, and the second end of the first capacitor C1 is connected to the second resistor R2 and the fourth resistor R4, respectively; the first end of the second capacitor C2 is connected to the second resistor R2 and the fourth resistor R4, respectively, and the second end of the second capacitor C2 is grounded. Exemplarily, the first capacitor C1 and the second capacitor C2 are filter capacitors that perform a filtering function, filtering the currents of the L and N lines collected by the current transformer U2 before inputting them into the operational amplifier U1.

[0059] Specifically, the sampling circuit 10 further includes a fifth resistor R5; wherein a first end of the fifth resistor R5 is connected to the power supply terminal Vref, and a second end of the fifth resistor R5 is connected to the 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 R5 is a reference terminal resistor.

[0060] Specifically, the sampling circuit 10 further includes a sixth resistor R6 and a third capacitor C3; wherein a first end of the sixth resistor R6 is connected to the negative input terminal OA0_N of the operational amplifier U1, and a second end of the sixth resistor R6 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 third capacitor C3 is connected to the output terminal OA0_OUT of the operational amplifier U1. Exemplarily, the sixth resistor R6 and the third capacitor C3 form a feedback loop.

[0061] Specifically, the sampling circuit 10 further includes a seventh resistor R7 and a fourth capacitor C4; wherein a first end of the seventh resistor R7 is connected to the output end of the operational amplifier U1, and a second end of the seventh resistor R7 is connected to the frequency conversion controller 20; a first end of the fourth capacitor C4 is connected to the second end of the seventh resistor R7, and a second end of the fourth capacitor C4 is grounded. Exemplarily, the amplified output signal output by the operational amplifier U1 is filtered by the seventh resistor R7 and the fourth capacitor C4, then output from the output end OUT_MCU of the sampling circuit and finally input to the MCU 21 for processing.

[0062] Compared to the prior art, the refrigerator disclosed in the present invention is equipped 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 is greater than a preset current threshold, the current difference between the leakage current and the current threshold is calculated. The frequency-carrier increase amount of the frequency conversion controller is then determined based on the current difference, and the target operating frequency of the frequency conversion controller is obtained based on the frequency-carrier increase amount. By adopting the embodiment of the present invention, the carrier frequency (switching power device frequency) of the frequency conversion controller can be increased, and the output carrier frequency of the frequency conversion controller can be effectively adjusted to achieve compatibility with GFCI. The PWM carrier frequency of the frequency conversion controller is increased, which can effectively prevent tripping.

[0063] See also Figure 10 , Figure 10 is a flow chart of a refrigerator control method provided by an embodiment of the present invention. The refrigerator includes a sampling circuit for sampling leakage current at a power input terminal of the refrigerator. The method includes:

[0064] S1. Obtaining the leakage current collected by the sampling circuit;

[0065] S2. When the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold;

[0066] S3. Determine a frequency load increase of the frequency conversion controller in the refrigerator according to the current difference, and obtain a target operating frequency of the frequency conversion controller according to the frequency load increase.

[0067] Specifically, a PID module is provided in the frequency conversion controller. After obtaining the target operating frequency of the frequency conversion controller according to the frequency-carrying increase amount, the method includes: using the target operating frequency as the input of the PID module, and outputting the PWM carrier frequency through PID regulation.

[0068] Specifically, the target operating frequency is greater than or equal to 7KHz.

[0069] Specifically, 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.

[0070] Specifically, the sampling circuit also includes a first resistor, a second resistor, a third resistor and a fourth resistor; wherein the positive input terminal of the operational amplifier is connected to the current transformer through the first resistor and the third resistor, and the negative input terminal of the operational amplifier is connected to the current transformer through the second resistor and the fourth resistor.

[0071] Specifically, the sampling circuit also includes a first capacitor and a second capacitor; wherein the first end of the first capacitor is respectively connected to the first resistor and the third resistor, and the second end of the first capacitor is respectively connected to the second resistor and the fourth resistor; the first end of the second capacitor is respectively connected to the second resistor and the fourth resistor, and the second end of the second capacitor is grounded.

[0072] Specifically, the sampling circuit further includes a fifth resistor; wherein a first end of the fifth resistor is connected to a power supply end, and a second end of the fifth resistor is connected to a positive input end of the operational amplifier.

[0073] Specifically, the sampling circuit also includes a sixth resistor and a third capacitor; wherein, the first end of the sixth resistor is connected to the negative input terminal of the operational amplifier, and the second end of the sixth resistor is connected to the output terminal of the operational amplifier; the first end of the third capacitor is connected to the negative input terminal of the operational amplifier, and the second end of the third capacitor is connected to the output terminal of the operational amplifier.

[0074] Specifically, the sampling circuit also includes a seventh resistor and a fourth capacitor; wherein the first end of the seventh resistor is connected to the output end of the operational amplifier, and the second end of the seventh resistor is connected to the frequency conversion controller; the first end of the fourth capacitor is connected to the second end of the seventh resistor, and the second end of the fourth capacitor is grounded.

[0075] It is worth noting that the detailed working process of the refrigerator control method described in the embodiment of the present invention 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.

[0076] Compared to the prior art, the refrigerator control method disclosed in the present invention 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 is greater than a preset current threshold, the current difference between the leakage current and the current threshold is calculated. The frequency-load increase amount of the frequency conversion controller is then determined based on the current difference, and the target operating frequency of the frequency conversion controller is obtained based on the frequency-load increase amount. By adopting the embodiment of the present invention, the carrier frequency (switching power device frequency) of the frequency conversion controller can be increased, and the output carrier frequency of the frequency conversion controller can be effectively adjusted to achieve compatibility with GFCI. The PWM carrier frequency of the frequency conversion controller is increased, which can effectively prevent tripping.

[0077] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A refrigerator, characterized in that: include: a box body, in which at least one storage chamber is formed; A door is provided at the opening of the storage chamber and is used to open and close the storage chamber; a compressor, disposed within the housing, for providing power for a refrigeration cycle of the refrigerator; A sampling circuit is provided in the box and is used to sample the leakage current of the 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 leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold; The frequency load increase amount of the frequency conversion controller is determined according to the current difference, and the target operating frequency of the frequency conversion controller is obtained according to the frequency load increase amount.

2. The refrigerator according to claim 1, wherein The frequency conversion controller is provided with a PID module. After obtaining the target operating frequency of the frequency conversion controller according to the frequency load increase, the frequency conversion controller is further configured to: The target operating frequency is used as the input of the PID module, and the PWM carrier frequency is output through PID regulation.

3. The refrigerator according to claim 1 is characterized in that The target operating frequency is greater than or equal to 7 KHz and less than or equal to 20 KHz.

4. The refrigerator according to claim 1, 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.

5. The refrigerator according to claim 4, wherein: The sampling circuit further includes a first resistor, a second resistor, a third resistor, and a fourth resistor; wherein the positive input terminal of the operational amplifier is connected to the current transformer through the first resistor and the third resistor, and the negative input terminal of the operational amplifier is connected to the current transformer through the second resistor and the fourth resistor.

6. The refrigerator according to claim 5, wherein The sampling circuit also includes a first capacitor and a second capacitor; wherein the first end of the first capacitor is connected to the first resistor and the third resistor respectively, and the second end of the first capacitor is connected to the second resistor and the fourth resistor respectively; the first end of the second capacitor is connected to the second resistor and the fourth resistor respectively, and the second end of the second capacitor is grounded.

7. The refrigerator according to claim 4, wherein: The sampling circuit further includes a fifth resistor; wherein a first end of the fifth resistor is connected to a power supply end, and a second end of the fifth resistor is connected to a positive input end of the operational amplifier.

8. The refrigerator according to claim 4, wherein: The sampling circuit also includes a sixth resistor and a third capacitor; wherein, the first end of the sixth resistor is connected to the negative input terminal of the operational amplifier, and the second end of the sixth resistor is connected to the output terminal of the operational amplifier; the first end of the third capacitor is connected to the negative input terminal of the operational amplifier, and the second end of the third capacitor is connected to the output terminal of the operational amplifier.

9. The refrigerator according to claim 4, wherein: The sampling circuit also includes a seventh resistor and a fourth capacitor; wherein a first end of the seventh resistor is connected to the output end of the operational amplifier, and a second end of the seventh resistor is connected to the frequency conversion controller; a first end of the fourth capacitor is connected to the second end of the seventh resistor, and a second end of the fourth capacitor is grounded.

10. A refrigerator control method, characterized in that: The refrigerator includes a sampling circuit for sampling leakage current at a power input terminal of the refrigerator. Then, the method includes: Obtaining the leakage current collected by the sampling circuit; When the leakage current is greater than a preset current threshold, calculating a current difference between the leakage current and the current threshold; The frequency load increase amount of the frequency conversion controller in the refrigerator is determined according to the current difference, and the target operating frequency of the frequency conversion controller is obtained according to the frequency load increase amount.

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