CN114234520B - Refrigerator and defrosting control method thereof - Google Patents

Abstract

The invention discloses a refrigerator and a defrosting control method thereof, wherein the correlation between the frosting of the surface of an evaporator and the first input voltage of a first fan can be utilized to establish the corresponding relation between the frosting quantity of the evaporator and the first input voltage of the fan under a specific rotating speed. When the first fan actually operates, the frost amount of the evaporator is indirectly judged by detecting the stable operation voltage of the first fan, and defrosting is timely started. The defrosting device can accurately identify the frosting degree of the evaporator, the defrosting heating pipe is started at a better time to defrost the evaporator, energy waste caused by premature defrosting is avoided, deterioration of the refrigeration performance of the refrigerator caused by untimely defrosting is avoided, and defrosting according to needs is realized in the actual use process.

Description

Refrigerator and defrost control method thereof

Technical field

The present invention relates to the technical field of refrigerator control, and in particular to a refrigerator and a defrost control method thereof.

Background technique

Defrost energy consumption accounts for 10% to 20% of the operating energy consumption of air-cooled refrigerators. Optimizing refrigerator defrost control can significantly improve the energy efficiency index of the entire machine. At present, the defrost judgment condition commonly used in refrigerator products is to use the cumulative running time of the whole machine or compressor, which is also called the variable frost cycle control method. That is: set a minimum defrost time tmi n and a maximum defrost time tmax. In more detail, the defrost intervals for different ambient temperatures/humidities, setting gears, and door opening and closing times are set based on experience. When the programmed defrost time is reached, the defrost heater is started for defrosting, and the frost is judged. After the stratification is exhausted, it stops, resumes cooling, and the cycle begins again.

This defrosting method with time as the control parameter cannot accurately capture the actual amount of frost on the evaporator surface under different working conditions, and there are problems such as premature defrost and untimely defrost. For example, when the user is actually using it, putting food with high water content or frequently opening and closing the door will accelerate the frosting of the evaporator. When the programmed defrost time interval is not reached, the frost layer on the evaporator surface has accumulated excessively and affected normal replacement. heat, the refrigeration efficiency decreases; when the user does not put food in or open the door for a long time, there is less frost on the evaporator, and when the defrost time interval has met the program setting, the heat exchange performance does not decrease significantly, and premature defrost occurs. This leads to problems such as increased energy consumption of the refrigerator, frequent defrosting and temperature rise affecting food quality.

Contents of the invention

The purpose of the embodiments of the present invention is to provide a refrigerator and a defrost control method thereof that can accurately identify the degree of frost on the evaporator, turn on the defrost heating pipe at a better time to defrost the evaporator, and avoid premature defrosting causing energy It also avoids waste and avoids the deterioration of the refrigeration performance of the refrigerator caused by delayed defrosting, and enables on-demand defrosting during actual use.

To achieve the above objects, embodiments of the present invention provide a refrigerator, including:

The cold air circulation system includes an evaporator and a first fan. The evaporator is located between the air duct of the box and the inner tank. The first fan is located at the upper part of the evaporator. The first fan circulates the air to circulate the cold air. The cold energy of the evaporator is transferred to the room;

The controller is configured as:

When detecting that the first fan enters a stable operating state, obtain the first input voltage of the first fan;

When the first input voltage is less than the preset first voltage threshold, perform a defrost operation after the refrigerator is shut down;

During the execution of the defrost operation, obtain the defrost temperature of the evaporator;

When the defrost temperature reaches the preset defrost exit temperature, defrost is stopped.

As an improvement to the above solution, the controller is also configured to:

Input a preset starting voltage to start the first fan, and detect the real-time rotation speed of the first fan;

Adjust the starting voltage to adjust the real-time speed;

When the real-time rotation speed is equal to the preset rated rotation speed, it is determined that the first fan is in a stable operating state.

As an improvement to the above solution, the refrigerator also includes:

The heat dissipation system includes a condenser and a second fan, the second fan is located on one side of the condenser;

The controller is also configured to:

When detecting that the second fan enters a stable operating state, obtain the second input voltage of the second fan;

When the second input voltage is less than the preset second voltage threshold, a prompt message that the condenser needs to be cleaned is sent.

As an improvement to the above solution, the first voltage threshold satisfies the following formula:

Uh=U0-ηΔU;

η=(U0-UX)/(U0-UN);

Wherein, Uh is the first voltage threshold; U0 is the input voltage collected after the first fan runs smoothly without frost on the evaporator surface or after a single defrost is completed; ΔU is the evaporator The difference between the input voltage of the first fan in the two states of no frost and complete frost; eta is the frost coefficient; UN is the input voltage of the first fan when the evaporator is full of frost; UX is the power consumption in the cooling cycle The input voltage UX of the first fan corresponds to the turning point of the change in power consumption.

In order to achieve the above object, an embodiment of the present invention also provides a refrigerator defrost control method, including:

When it is detected that the first fan in the refrigerator enters a stable operating state, the first input voltage of the first fan is obtained; wherein the first fan is located on the upper part of the evaporator in the refrigerator;

When the first input voltage is less than the preset first voltage threshold, perform a defrost operation after the refrigerator is shut down;

During the execution of the defrost operation, obtain the defrost temperature of the evaporator;

When the defrost temperature reaches the preset defrost exit temperature, defrost is stopped.

As an improvement of the above solution, the method also includes:

Input a preset starting voltage to start the first fan, and detect the real-time rotation speed of the first fan;

Adjust the starting voltage to adjust the real-time speed;

When the real-time speed is equal to the preset rated speed, it is determined that the first fan is in a stable operating state.

As an improvement of the above solution, the method also includes:

When it is detected that the second fan enters a stable operating state, the second input voltage of the second fan is obtained; wherein the second fan is located on one side of the condenser in the refrigerator;

When the second input voltage is less than the preset second voltage threshold, a prompt message that the condenser needs to be cleaned is sent.

As an improvement to the above solution, the first voltage threshold satisfies the following formula:

Uh=U0-ηΔU;

η=(U0-UX)/(U0-UN);

Wherein, Uh is the first voltage threshold; U0 is the input voltage collected after the first fan runs smoothly without frost on the evaporator surface or after a single defrost is completed; ΔU is the evaporator The difference between the input voltage of the first fan in the two states of no frost and complete frost; eta is the frost coefficient; UN is the input voltage of the first fan when the evaporator is full of frost; UX is the power consumption in the cooling cycle The input voltage UX of the first fan corresponds to the turning point of the change in power consumption.

Compared with the prior art, the refrigerator and its defrost control method disclosed in the present invention utilize the correlation between the frost on the evaporator surface and the first input voltage of the first fan to establish the evaporator junction at a specific rotation speed. The corresponding relationship between the amount of frost and the first input voltage of the first fan. When the first fan is actually running, by detecting the stable operating voltage of the first fan, the evaporator frost amount is indirectly determined, and defrost is started in a timely manner. It can accurately identify the degree of frost on the evaporator and turn on the defrost heating pipe at the optimal time to defrost the evaporator, thereby avoiding energy waste caused by premature defrost and avoiding the deterioration of the refrigerator's refrigeration performance caused by untimely defrost. During actual use Achieve defrosting on demand. In addition, by utilizing the correlation between the input voltage of the second fan and the amount of dust accumulated in the condenser, at a specific rotation speed, a corresponding relationship between the amount of dust accumulated in the condenser and the second input voltage can be established, which can promptly remind the user to clean the condenser.

Description of the drawings

Figure 1 is a schematic structural diagram of a refrigerator provided by an embodiment of the present invention;

Figure 2 is another structural schematic diagram of a refrigerator provided by an embodiment of the present invention;

Figure 3 is a work flow chart of the controller provided by the embodiment of the present invention;

Figure 4 is a flow chart of a refrigerator defrost control method provided by an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

Referring to Figure 1, Figure 1 is a structural representation of a refrigerator provided by an embodiment of the present invention. The refrigerator includes:

The cold air circulation system 10 includes an evaporator and a first fan. The evaporator is located between the air duct of the box and the inner tank. The first fan is located at the upper part of the evaporator. The first fan circulates the air through the air. The cooling capacity of the evaporator is transferred to the room;

Controller 20 is configured as:

When detecting that the first fan enters a stable operating state, obtain the first input voltage of the first fan;

When the first input voltage is less than the preset first voltage threshold, perform a defrost operation after the refrigerator is shut down;

During the execution of the defrost operation, obtain the defrost temperature of the evaporator;

When the defrost temperature reaches the preset defrost exit temperature, defrost is stopped.

For example, the existing air-cooled refrigerator mainly includes a refrigeration system composed of a compressor, a condenser, a capillary tube, and an evaporator, a cold air circulation system composed of an evaporator, a first fan, an air duct, and a compartment. The compressor compartment cooling system composed of the second fan and compressor, and the control system. Among them, the evaporator is arranged between the air duct of the box and the inner tank, and the first fan is located on the upper part of the evaporator. When the first fan is running, the cold energy of the evaporator is transferred to the compartment through air circulation to realize the cooling and cooling process. . In addition, there is a defrost heating tube at the bottom of the evaporator. When a defrost command is received, the defrost heating tube is energized and heated to melt the ice condensed on the evaporator. The condenser is located upstream of the second fan, and the compressor is located downstream of the second fan. The rear cover of the compressor is provided with heat dissipation holes to facilitate air circulation. When the second fan is running, The pressure difference between the front and rear of the second fan drives the air around the box into the compressor compartment through the heat dissipation hole on the right side, passes through the bottom condenser, the second fan, and the compressor in sequence, and is finally discharged through the heat dissipation hole on the left side. In the process, The circulating air removes heat from the condenser and compressor.

Referring to FIG. 2 , the refrigerator also includes a signal acquisition module 40 , a defrost module 50 , a fan driving module 60 and a display module 70 . The fan drive module 60 is connected to the controller 20 through connecting wires and is divided into a motor drive circuit 61 and a rotation speed detection circuit 62. The motor drive circuit 61 receives the drive signal output by the controller 20 and drives the motor to drive the fan. The blades rotate; the rotation speed detection circuit 62 is composed of a Hall element and is used to detect the actual rotation speed of the first fan and the second fan, which is received by the signal acquisition module 40 and then transmitted to the controller 20 . The defrost module 50 includes a defrost heating circuit 51 and an evaporator temperature sensor 52 . The controller 20 controls the on and off of the defrost heating circuit 51 . The evaporator temperature sensor 52 feeds back signals to the signal acquisition module 40 . In addition, the signal acquisition module 40 reads the first input voltage and the second input voltage of the motor and transmits them to the controller 20 . The display module 70 is used to display prompt information, for example, the prompt information is information prompting the user to clean the condenser.

Optionally, the controller 20 is also configured to:

Input a preset starting voltage to start the first fan, and detect the real-time rotation speed of the first fan;

Adjust the starting voltage to adjust the real-time speed;

When the real-time rotation speed is equal to the preset rated rotation speed, it is determined that the first fan is in a stable operating state.

Referring to Fig. 3, Fig. 3 shows the working process of the controller 20. The first fan operates at a program-preset starting voltage U, and the real-time rotation speed f of the first fan is detected. When the real-time speed f is higher than the rated speed f0, the starting voltage U is reduced. When the real-time speed f is lower than the rated speed f0, the starting voltage U is increased. Finally, the first fan speed reaches f0 and runs smoothly. After the first fan runs smoothly, the first input voltage U of the first fan is detected, and the first input voltage U is compared with the preset first voltage threshold Uh. If U<Uh, perform defrost operation, otherwise continue to run; when performing defrost, the evaporator defrost temperature Th is collected in real time. When the defrost temperature Th reaches the preset defrost exit temperature Tend, the defrost is stopped.

Optionally, the first voltage threshold satisfies the following formula:

Uh=U0-ηΔU;

η=(U0-UX)/(U0-UN);

Wherein, Uh is the first voltage threshold; U0 is the input voltage collected after the first fan runs smoothly without frost on the evaporator surface or after a single defrost is completed; ΔU is the evaporator The difference between the input voltage of the first fan in the two states of no frost and complete frost; eta is the frost coefficient; UN is the input voltage of the first fan when the evaporator is full of frost; UX is the power consumption in the cooling cycle The input voltage UX of the first fan corresponds to the turning point of the change in power consumption.

For example, in order to further improve the defrosting efficiency, an automatic correction method of the preset defrost voltage Uh is added. This method is based on the actual operating status of the fan to determine the amount of frost, which can avoid the amount of frost caused by the user's different food storage amounts and food stacking methods, as well as the fluctuations in duct assembly, motor parameters, and controller hardware parameters in mass production. judgment error, thereby improving the accuracy of judgment.

When there is no frost on the evaporator surface or after a single defrost is completed, the controller starts the first fan to run smoothly and collects the first input voltage U0. Thereafter, when the first fan is running stably in each refrigeration cycle, the first input voltage U of the first fan is collected, and U is compared with U0-ηΔU. When U<U0-ΔU, defrost is executed. ΔU and eta are determined by prototype test tests. For example, when the refrigerator starts running, ensure that there is no frost on the evaporator. When the first fan is running stably in each refrigeration cycle, collect the first input voltage of the first fan until the evaporator is full of frost, and record the first The input voltage is [U0, U1,...UN] in sequence. At the same time, the power consumption of each cooling cycle is calculated. The power consumption will inevitably show a trend of being unchanged at first and then slowly increasing. Find the first input voltage UX of the fan corresponding to the turning point of the change in power consumption, then η = (U0-UX)/(U0-UN).

Furthermore, the refrigerator also includes:

The heat dissipation system 30 includes a condenser and a second fan, the second fan is located on one side of the condenser;

The controller 20 is also configured to:

When detecting that the second fan enters a stable operating state, obtain the second input voltage of the second fan;

When the second input voltage is less than the preset second voltage threshold, a prompt message that the condenser needs to be cleaned is sent.

For example, when dust accumulates in the condenser, the air circulation area and air flow rate in the compressor chamber decrease, and the operating load and input and output electrical signals of the second fan will also change accordingly. For example, when the surface of the condenser is covered with dust and fluff, the air circulation flow rate decreases, and the second input voltage (power) of the second fan at the same rotation speed decreases accordingly. Using this characteristic, at a specific rotation speed, the corresponding relationship between the amount of dust accumulated in the condenser and the second input voltage of the fan can be established. By detecting the stable operating voltage of the fan, the degree of dust accumulation in the condenser can be indirectly determined and the user can be reminded to remove dust in time. The second voltage threshold can be obtained through laboratory measurement. When the second fan is running, the second input voltage U of the second fan is detected in real time, and the second input voltage U is compared with the preset second voltage threshold Ub. If U<Ub, send a reminder command to the display panel, otherwise continue running.

Compared with the prior art, the refrigerator disclosed in the embodiment of the present invention utilizes the correlation between the frost on the evaporator surface and the first input voltage of the first fan. At a specific rotation speed, it is possible to establish the relationship between the amount of frost on the evaporator and the first input voltage of the first fan. The corresponding relationship between the first input voltage of a fan. When the first fan is actually running, by detecting the stable operating voltage of the first fan, the evaporator frost amount is indirectly determined, and defrost is started in a timely manner. It can accurately identify the degree of frost on the evaporator and turn on the defrost heating pipe at the optimal time to defrost the evaporator, thereby avoiding energy waste caused by premature defrost and avoiding the deterioration of the refrigerator's refrigeration performance caused by untimely defrost. During actual use Achieve defrosting on demand. In addition, by utilizing the correlation between the input voltage of the second fan and the amount of dust accumulated in the condenser, at a specific rotation speed, a corresponding relationship between the amount of dust accumulated in the condenser and the second input voltage can be established, which can promptly remind the user to clean the condenser.

Referring to Figure 4, Figure 4 is a flow chart of a refrigerator defrost control method provided by an embodiment of the present invention. The refrigerator defrost control method includes:

S1. When it is detected that the first fan in the refrigerator enters a stable operating state, obtain the first input voltage of the first fan;

S2. When the first input voltage is less than the preset first voltage threshold, perform a defrost operation after the refrigerator is shut down;

S3. During the defrost operation, obtain the defrost temperature of the evaporator;

S4. When the defrost temperature reaches the preset defrost exit temperature, stop defrost.

For example, the existing air-cooled refrigerator mainly includes a refrigeration system composed of a compressor, a condenser, a capillary tube, and an evaporator, a cold air circulation system composed of an evaporator, a first fan, an air duct, and a compartment, and a condenser. , the second fan, the compressor compartment cooling system, and the control system. Among them, the evaporator is arranged between the air duct of the box and the inner tank, and the first fan is located on the upper part of the evaporator. When the first fan is running, the cold energy of the evaporator is transferred to the compartment through air circulation to realize the cooling and cooling process. . In addition, there is a defrost heating tube at the bottom of the evaporator. When a defrost command is received, the defrost heating tube is energized and heated to melt the ice condensed on the evaporator. The condenser is located upstream of the second fan, and the compressor is located downstream of the second fan. The rear cover of the compressor is provided with heat dissipation holes to facilitate air circulation. When the second fan is running, The pressure difference between the front and rear of the second fan drives the air around the box into the compressor compartment through the heat dissipation hole on the right side, passes through the bottom condenser, the second fan, and the compressor in sequence, and is finally discharged through the heat dissipation hole on the left side. In this process, The circulating air removes heat from the condenser and compressor.

Optionally, the refrigerator defrost control method also includes:

Input a preset starting voltage to start the first fan, and detect the real-time rotation speed of the first fan;

Adjust the starting voltage to adjust the real-time speed;

When the real-time rotation speed is equal to the preset rated rotation speed, it is determined that the first fan is in a stable operating state.

Exemplarily, the first fan operates with a program-preset starting voltage U, and the real-time rotation speed f of the first fan is detected. When the real-time speed f is higher than the rated speed f0, the starting voltage U is reduced. When the real-time speed f is lower than the rated speed f0, the starting voltage U is increased. Finally, the first fan speed reaches f0 and runs smoothly. After the first fan runs smoothly, the first input voltage U of the first fan is detected, and the first input voltage U is compared with the preset first voltage threshold Uh. If U<Uh, perform defrost operation, otherwise continue to run; when performing defrost, the evaporator defrost temperature Th is collected in real time. When the defrost temperature Th reaches the preset defrost exit temperature Tend, the defrost is stopped.

Optionally, the first voltage threshold satisfies the following formula:

Uh=U0-ηΔU;

η=(U0-UX)/(U0-UN);

Wherein, Uh is the first voltage threshold; U0 is the input voltage collected after the first fan runs smoothly without frost on the evaporator surface or after a single defrost is completed; ΔU is the evaporator The difference between the input voltage of the first fan in the two states of no frost and complete frost; eta is the frost coefficient; UN is the input voltage of the first fan when the evaporator is full of frost; UX is the power consumption in the cooling cycle The input voltage UX of the first fan corresponds to the turning point of change in power consumption.

For example, in order to further improve the defrosting efficiency, an automatic correction method of the preset defrost voltage Uh is added. This method is based on the actual operating status of the fan to determine the amount of frost, which can avoid the amount of frost caused by the user's different food storage amounts and food stacking methods, as well as the fluctuations in duct assembly, motor parameters, and controller hardware parameters in mass production. judgment error, thereby improving the accuracy of judgment.

When there is no frost on the evaporator surface or after a single defrost is completed, the controller starts the first fan to run smoothly and collects the first input voltage U0. Thereafter, when the first fan is running stably in each refrigeration cycle, the first input voltage U of the first fan is collected, and U is compared with U0-ηΔU. When U<U0-ΔU, defrost is executed. ΔU and eta are determined by prototype test testing. For example, when the refrigerator starts running, ensure that there is no frost on the evaporator. When the first fan is running stably in each refrigeration cycle, collect the first input voltage of the first fan until the evaporator is full of frost, and record the The first input voltage is [U0, U1,...UN] in sequence, and at the same time, the power consumption of each cooling cycle is calculated. The power consumption will inevitably show a trend of being unchanged at first and then slowly increasing. Find the first input voltage UX corresponding to the turning point of the change in power consumption, then eta = (U0-UX)/(U0-UN).

Furthermore, the refrigerator defrost control method also includes:

When detecting that the second fan enters a stable operating state, obtain the second input voltage of the second fan;

When the second input voltage is less than the preset second voltage threshold, a prompt message that the condenser needs to be cleaned is issued.

For example, when dust accumulates in the condenser, the air circulation area and air flow rate in the compressor chamber decrease, and the operating load and input and output electrical signals of the second fan will also change accordingly. For example, when the surface of the condenser is covered with dust and fluff, the air circulation flow rate decreases, and the second input voltage (power) of the second fan at the same rotation speed decreases accordingly. Utilizing this characteristic, at a specific rotation speed, a corresponding relationship between the amount of dust accumulated in the condenser and the second input voltage of the second fan can be established. By detecting the stable operating voltage of the fan, the degree of dust accumulation in the condenser can be indirectly determined and the user can be reminded to remove dust in time. The second voltage threshold can be obtained through laboratory measurement. When the fan is running, the second input voltage U' of the fan is detected in real time, and the second input voltage U' is compared with the preset second voltage threshold Ub. If U'<Ub, send a reminder command to the display panel, otherwise continue running.

Compared with the prior art, the refrigerator defrost control method disclosed in the embodiment of the present invention utilizes the correlation between the frost on the evaporator surface and the first input voltage of the first fan to establish the evaporator frost at a specific rotation speed. The corresponding relationship between the amount of frost and the first input voltage of the first fan. When the first fan is actually running, by detecting the stable operating voltage of the first fan, the evaporator frost amount is indirectly determined, and defrost is started in a timely manner. It can accurately identify the degree of frost on the evaporator and turn on the defrost heating pipe at the optimal time to defrost the evaporator, thereby avoiding energy waste caused by premature defrost and avoiding the deterioration of the refrigerator's refrigeration performance caused by untimely defrost. During actual use Achieve defrosting on demand. In addition, by utilizing the correlation between the input voltage of the second fan and the amount of dust accumulated in the condenser, at a specific rotation speed, a corresponding relationship between the amount of dust accumulated in the condenser and the second input voltage can be established, which can promptly remind the user to clean the condenser.

The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also regarded as It is the protection scope of the present invention.

Claims (4)

1. A refrigerator, comprising:

the cold air circulation system comprises an evaporator and a first fan, the evaporator is arranged between the air duct of the box body and the inner container, the first fan is positioned at the upper part of the evaporator, and the first fan transfers the cold energy of the evaporator into the room through air circulation;

the defrosting heating pipe is arranged at the bottom of the evaporator and is electrified to heat so as to melt the frost condensed on the evaporator;

the controller is configured to:

when the first fan is detected to enter a stable running state, acquiring a first input voltage of the first fan;

when the first input voltage is smaller than a preset first voltage threshold value, defrosting operation is executed after the refrigerator is stopped;

acquiring a defrosting temperature of the evaporator in the process of executing the defrosting operation;

stopping defrosting when the defrosting temperature reaches a preset defrosting exit temperature;

the controller is further configured to:

inputting a preset starting voltage to start the first fan, and detecting the real-time rotating speed of the first fan;

adjusting the starting voltage to adjust the real-time rotation speed;

when the real-time rotating speed is equal to a preset rated rotating speed, judging that the first fan is in a stable running state;

the first voltage threshold satisfies the following formula:

Uh＝U0-ηΔU；

η＝(U0-UX)/(U0-UN)；

wherein Uh is the first voltage threshold; u0 is input voltage acquired after the first fan runs stably after no frost is formed on the surface of the evaporator or after single defrosting is finished; Δu is the difference between the input voltages of the first fan when the evaporator is in the frost-free state and the frost-free state; η is the frost coefficient; UN is the input voltage of the first fan when the evaporator is full of frost; and UX is the input voltage UX of the first fan corresponding to the turning point of the power consumption change in the power consumption of the refrigeration cycle.

2. The refrigerator of claim 1, further comprising:

the heat dissipation system comprises a condenser and a second fan, wherein the second fan is arranged on one side of the condenser;

the controller is further configured to:

when the second fan is detected to enter a stable running state, acquiring a second input voltage of the second fan;

and when the second input voltage is smaller than a preset second voltage threshold value, sending out prompt information for cleaning the condenser.

3. A defrosting control method for a refrigerator, comprising:

when a first fan in a refrigerator is detected to enter a stable running state, acquiring a first input voltage of the first fan; wherein the first fan is arranged at the upper part of an evaporator in the refrigerator;

when the first input voltage is smaller than a preset first voltage threshold value, defrosting operation is executed after the refrigerator is stopped;

acquiring a defrosting temperature of the evaporator in the process of executing the defrosting operation;

stopping defrosting when the defrosting temperature reaches a preset defrosting exit temperature;

the method further comprises the steps of:

inputting a preset starting voltage to start the first fan, and detecting the real-time rotating speed of the first fan;

adjusting the starting voltage to adjust the real-time rotation speed;

when the real-time rotating speed is equal to a preset rated rotating speed, judging that the first fan is in a stable running state;

the first voltage threshold satisfies the following formula:

Uh＝U0-ηΔU；

η＝(U0-UX)/(U0-UN)；

wherein Uh is the first voltage threshold; u0 is input voltage acquired after the first fan runs stably after no frost is formed on the surface of the evaporator or after single defrosting is finished; Δu is the difference between the input voltages of the first fan when the evaporator is in the frost-free state and the frost-free state; η is the frost coefficient; UN is the input voltage of the first fan when the evaporator is full of frost; and UX is the input voltage UX of the first fan corresponding to the turning point of the power consumption change in the power consumption of the refrigeration cycle.

4. The refrigerator defrosting control method of claim 3, wherein the method further comprises:

when the second fan is detected to enter a stable running state, acquiring a second input voltage of the second fan; wherein the second fan is arranged at one side of a condenser in the refrigerator;

and when the second input voltage is smaller than a preset second voltage threshold value, sending out prompt information for cleaning the condenser.