A variable frequency refrigerator rotation speed control method

Abstract

The application provides a variable frequency refrigerator rotating speed control method, comprising: determining the initial rotating speed of the compressor according to the ambient temperature; obtaining the difference between the current temperature of the refrigeration chamber and the start-up point temperature at a preset judgment time; when the maximum temperature difference is greater than a first threshold value and the speed-up condition is met for at least two times in succession, increasing the compressor by a first preset gear; obtaining the continuous running time of the compressor, increasing the second preset gear when the first preset time threshold value is reached, and setting the highest speed limit when the second preset time threshold value is reached; comparing the rotating speed obtained based on the temperature difference speed-up and the rotating speed obtained based on the running time speed-up with the highest speed limit, and taking the smaller value as the final running rotating speed. The method solves the problems of rotating speed fluctuation caused by single judgment speed-up, lack of effective control during continuous running, and conflict of defrosting and noise reduction modes.

Description

Technical Field

[0001] This invention relates to the field of refrigerator control technology, and in particular to a method for controlling the rotation speed of a variable frequency refrigerator. Background Technology

[0002] Inverter refrigerators, with their comprehensive advantages in energy saving, food preservation, and low noise, have gradually replaced traditional fixed-frequency refrigerators as the mainstream product in the market. Their core lies in the use of an inverter compressor, which dynamically adjusts its speed according to the actual cooling needs inside the refrigerator, thus achieving an optimal balance between energy saving, maintaining food freshness, and suppressing operating noise. Compared to the constant speed operation of a fixed-frequency compressor, the inverter compressor can flexibly adjust its output power based on real-time temperature changes in each compartment, such as the refrigerator and freezer, effectively avoiding the energy waste and temperature fluctuations caused by the frequent start-stop of a fixed-frequency compressor.

[0003] The speed control of the inverter compressor is closely related to the temperature status of each compartment in the refrigerator. When the temperature of the refrigerator or freezer compartment rises due to factors such as frequent opening and closing of the door by the user, placing a large amount of room temperature food at one time, or a significant increase in the ambient temperature, the control system needs to promptly increase the compressor speed to enhance the refrigeration cycle and cause the compartment temperature to quickly drop back to the set range. Conversely, when the compartment temperature is close to or has reached the target value, the system should reduce the compressor speed to a lower level to minimize energy consumption while maintaining temperature stability.

[0004] Currently, the most widely adopted speed control strategy for inverter refrigerators in the industry is the "preset speed - temperature difference feedback" mode. This mode typically pre-sets a set of basic speed values ​​under typical laboratory conditions. Then, during actual refrigerator operation, it relies on the temperature deviation detected by the compartment temperature sensor (i.e., the difference between the measured temperature and the set temperature) as a feedback signal to correct and adjust the compressor speed. However, this real-time feedback mechanism based on a single temperature difference threshold has revealed several technical shortcomings in practical applications: Firstly, temperature difference feedback often triggers speed increase / decrease commands based on only a single temperature sampling result. Due to factors such as airflow disturbances inside the refrigerator, defrosting cycles, and door seal leaks, instantaneous temperature fluctuations can easily occur. This single judgment can easily lead to frequent and irregular jumps in compressor speed, which not only aggravates the wear and tear on mechanical parts and shortens the compressor's lifespan, but also undermines the stability and reliability of the entire machine's operation.

[0005] Secondly, existing control schemes generally lack effective speed-increasing strategies for scenarios where the compressor operates continuously under high load for extended periods. When the refrigerator is in extreme conditions such as high temperature environment, continuous intrusion of large heat load, or the refrigeration system running continuously without stopping, relying solely on conventional temperature difference feedback for fine-tuning often fails to provide sufficient cooling capacity in time. This results in slow cooling rate of the compartments, with the compressor running at high speed for extended periods without stopping, thereby affecting the preservation effect and increasing unnecessary energy consumption. Summary of the Invention

[0006] This application provides a variable frequency refrigerator speed control method to solve the problems in the prior art, such as speed fluctuation caused by single judgment and speed increase, lack of effective control in continuous operation, and conflict between defrosting and noise reduction modes and conventional control.

[0007] The method includes: The initial speed of the compressor is determined based on the ambient temperature; At a preset judgment time, the current temperature of at least one cooling room and the temperature difference between the current temperature and the start-up temperature corresponding to the current temperature are obtained, and the maximum temperature difference among all the temperature differences is used as the judgment basis; when the maximum temperature difference is greater than the first temperature difference threshold and the speed-up condition is met at least twice in a row, the compressor is increased from the initial speed by a first preset number of gears. The continuous operating time of the compressor is obtained; when the continuous operating time reaches a first preset time threshold, the speed of the compressor is increased from the current speed by a second preset number of gears; when the continuous operating time reaches the second preset time threshold, the speed of the compressor is set to the maximum speed limit; the second preset time threshold is greater than the first preset time threshold. The speed determined by the acceleration based on the room temperature difference and the speed determined by the acceleration based on the continuous running time are compared with the maximum speed limit, and the smaller value is taken as the final operating speed of the compressor.

[0008] In some implementations, the preset judgment time includes the time when the compressor starts, the time when any of the refrigeration rooms issues a refrigeration request, and the time every third preset time threshold during the operation of the compressor.

[0009] In some implementations, when any of the refrigerated compartments is in defrost mode, the temperature difference of that compartment is not calculated, and the rate-up rule based on the temperature difference of that compartment is not executed.

[0010] In some embodiments, the method further includes intelligent noise reduction mode processing, including: When the inverter refrigerator is operating in intelligent noise reduction mode, the maximum operating speed of the compressor is limited to be lower than the maximum speed limit; and within the fourth preset time threshold after exiting the intelligent noise reduction mode, the step of judging the room temperature difference acceleration is not executed.

[0011] In some implementations, when the compressor is in intelligent noise reduction mode, the recording of the compressor's continuous operating time is paused, and the timing is restarted after exiting the intelligent noise reduction mode.

[0012] In some implementations, the first temperature difference threshold is 4°C, the first preset time threshold is 90 minutes, and the second preset time threshold is 120 minutes.

[0013] In some embodiments, determining the initial compressor speed based on the ambient temperature includes: Obtain the ambient temperature of the environment where the inverter refrigerator is located; The initial speed is obtained by querying the ambient temperature-speed mapping table and the ambient temperature; different ambient temperature ranges correspond to different initial speed gears.

[0014] In some embodiments, the method further includes speed gear conversion, including: Multiple speed gears are preset, and the speed value corresponding to each gear is calculated by multiplying the difference between the base speed and the gear number minus one by a preset coefficient; the maximum speed limit corresponds to the speed value of a non-integer gear.

[0015] In some embodiments, the refrigeration compartment includes at least a refrigerator compartment and a freezer compartment; the larger of the temperature difference between the refrigerator compartment and the freezer compartment is used as the maximum temperature difference in the process of determining the rate of temperature difference rise.

[0016] In some implementations, the temperature difference is the difference between the current temperature of the corresponding room and its start-up temperature when the current temperature of the refrigeration room is greater than or equal to its start-up temperature.

[0017] As described above, this application provides a method for controlling the speed of a variable frequency refrigerator. The method includes determining the initial speed of the compressor based on the ambient temperature; at a preset judgment time, acquiring the temperature difference between the current temperature of at least one refrigeration compartment and the start-up temperature corresponding to the current temperature, and using the maximum temperature difference among all the temperature differences as the judgment basis; when the maximum temperature difference is greater than a first temperature difference threshold and the speed-up condition is met at least twice consecutively, increasing the compressor speed from the initial speed by a first preset number of gears; acquiring the continuous running time of the compressor; when the continuous running time reaches a first preset time threshold, increasing the current speed of the compressor by a second preset number of gears; when the continuous running time reaches a second preset time threshold, setting the current speed of the compressor to the maximum speed limit; the second preset time threshold is greater than the first preset time threshold; comparing the speed determined based on the room temperature difference and the speed determined based on the continuous running time with the maximum speed limit, and taking the smaller value as the final operating speed of the compressor. This application solves the problems in the prior art caused by speed fluctuations due to single-judgment-based speed increase, lack of effective control during continuous operation, and conflict between defrosting and noise reduction modes and conventional control by using the above method. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a variable frequency refrigerator speed control method according to this application; Figure 2 This is a flowchart of the intelligent noise reduction mode processing in a variable frequency refrigerator speed control method according to this application; Figure 3 This is a flowchart illustrating the speed range conversion in a variable frequency refrigerator speed control method according to this application. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0022] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0023] See Figure 1 As can be seen, this embodiment provides a method for controlling the rotational speed of a variable frequency refrigerator, the method comprising: S11 determines the initial speed of the compressor based on the ambient temperature.

[0024] Specifically, in this embodiment, the initial speed of the compressor in the refrigerator is first set according to the temperature of the environment in which the inverter refrigerator is located, and then the subsequent speed adjustment is carried out.

[0025] The specific method for obtaining the initial rotational speed includes obtaining the ambient temperature of the environment where the inverter refrigerator is located; querying the ambient temperature-rotational speed mapping table and the ambient temperature to obtain the initial rotational speed; different ambient temperature ranges correspond to different initial rotational speed levels.

[0026] The method further includes: S12, at a preset judgment time, obtain the temperature difference between the current temperature of at least one refrigeration room and the start-up temperature corresponding to the current temperature, and use the maximum temperature difference among all the temperature differences as the judgment basis; when the maximum temperature difference is greater than the first temperature difference threshold and the speed-up condition is met at least twice consecutively, increase the compressor from the initial speed to the first preset number of gears.

[0027] Specifically, in this embodiment, after setting the initial speed, at each preset judgment time, the temperature difference between the current temperature of the refrigerator compartment and / or the freezer compartment and the start-up temperature corresponding to the current temperature is obtained. In the case of multiple compartments, the maximum temperature difference is used as the judgment basis, and a judgment is made based on the maximum temperature, thereby obtaining the temperature-based adjustment scheme of the compressor.

[0028] The temperature difference is the difference between the current temperature of the corresponding room and its start-up temperature when the current temperature of the refrigeration room is greater than or equal to its start-up temperature.

[0029] The preset judgment time includes the time when the compressor starts, the time when any of the refrigeration rooms issues a refrigeration request, and the time every third preset time threshold during the operation of the compressor.

[0030] The three specific times for performing temperature difference judgment cover various scenarios such as compressor start-up and shutdown, sudden load changes (such as opening the door or putting in hot food), and periodic inspections, ensuring the timeliness and comprehensiveness of the control logic and enabling it to quickly respond to changes in various cooling demands.

[0031] It should be noted that when any of the aforementioned refrigeration compartments is in defrost mode, the temperature difference of that compartment is not calculated, and the speed-up rule based on that compartment's temperature difference is not executed. During defrost, the compartment temperature may rise abnormally. If temperature difference judgment is still performed at this time, it is very easy to trigger unnecessary speed-up, resulting in energy waste and excessive compressor operation. This logic avoids ineffective speed-up, improving control accuracy and energy-saving effect.

[0032] The method further includes: S13, obtain the continuous running time of the compressor; when the continuous running time reaches a first preset time threshold, increase the speed of the compressor from the current speed to a second preset level; when the continuous running time reaches a second preset time threshold, set the speed of the compressor to the maximum speed limit; the second preset time threshold is greater than the first preset time threshold.

[0033] Specifically, in this embodiment, after the temperature-based speed adjustment is completed, the continuous running time of the compressor is obtained, and a speed adjustment scheme based on the continuous running time and preset different time thresholds is determined.

[0034] The method further includes: S14, compare the speed determined by the room temperature difference and the speed determined by the continuous running time with the maximum speed limit, and take the smaller value as the final operating speed of the compressor.

[0035] Specifically, this embodiment integrates three mechanisms: initial setting based on ambient temperature, dynamic fine-tuning based on real-time load (temperature difference), and forced speed-up to cope with continuous high load (continuous running time). Through the speed-up logic of "meeting the condition twice consecutively," malfunctions caused by instantaneous temperature fluctuations are effectively suppressed, ensuring the stable operation of the compressor. Simultaneously, the "continuous running time speed-up" mechanism solves the problems of slow cooling and prolonged compressor shutdown in traditional solutions under high load conditions, thus improving refrigeration efficiency.

[0036] Wherein, the first temperature difference threshold is 4℃, the first preset time threshold is 90 minutes, and the second preset time threshold is 120 minutes.

[0037] Wherein, when the refrigeration compartment includes a refrigerator compartment and a freezer compartment; in the process of determining the rate of increase of the temperature difference between the compartments, the larger of the temperature difference between the refrigerator compartment and the freezer compartment is taken as the maximum temperature difference.

[0038] See Figure 2 Furthermore, in some embodiments, the method further includes intelligent noise reduction mode processing, including: S21, when the inverter refrigerator is running in intelligent noise reduction mode, the maximum operating speed of the compressor is limited to be lower than the maximum speed limit; and within the fourth preset time threshold after exiting the intelligent noise reduction mode, the step of judging the room temperature difference increase is not executed.

[0039] Specifically, in this embodiment, on the one hand, the maximum speed is directly limited in noise reduction mode to fundamentally ensure low-noise operation. On the other hand, a "quiet period" is set after exiting the noise reduction mode to shield the speed increase due to temperature difference, preventing an abrupt change in noise caused by an immediate increase in speed due to temperature rise after the noise reduction mode ends, which greatly improves the user's comfort before and after noise reduction mode.

[0040] It should be noted that because the compressor speed is manually limited in intelligent noise reduction mode, its operating characteristics differ from those in normal mode. Excluding the running time in this mode allows for a more accurate reflection of the compressor's actual continuous working time under high load conditions, making the judgment of "continuous running time speed-up" more scientific and reasonable, and avoiding incorrect speed-up timing due to interference from the noise reduction mode.

[0041] See Figure 3 Furthermore, in some embodiments, the method further includes speed gear conversion, including: S31, multiple speed gears are preset, and the speed value corresponding to each gear is calculated by multiplying the difference between the base speed and the gear number minus one by a preset coefficient; the maximum speed limit corresponds to the speed value of a non-integer gear.

[0042] Specifically, in this embodiment, the speed gear is calculated in a specific way, which makes the speed adjustment more quantitative and precise; in particular, setting the maximum speed limit to a non-integer gear value can better control noise and vibration while approaching the performance limit, reflecting the trade-off between performance and comfort.

[0043] Example 1: In this embodiment, the speed range of the inverter compressor is 1200rpm~4500rpm; the speed settings are divided into 1 to 12, with each setting corresponding to a speed of 1200 + (N-1) × 300rpm (N = 1, 2, ... 12), where setting 1 corresponds to 1200rpm and setting 12 corresponds to 4500rpm. To ensure that refrigerator noise does not affect consumer complaints, the maximum speed Smax is limited to 4320rpm; the start-up points for each compartment are set according to conventional refrigerator control logic, with a typical start-up point of 6℃ for the refrigerator compartment and -18℃ for the freezer compartment.

[0044] Determine the initial rotational speed: When the refrigerator is first powered on, the control board determines the initial speed setting based on the ambient temperature detected by the ambient temperature sensor, referring to a table. The ambient temperature-speed correspondence in this embodiment is shown in Table 1. Table 1. Ambient Temperature-Speed ​​Rotation Ratio

[0045] Detect the temperature of each room and calculate the temperature difference: The current temperature of the refrigerator compartment (Tr_current) is detected by a refrigerator temperature sensor, and the current temperature of the freezer compartment (Tf_current) is detected by a freezer temperature sensor. The temperature difference between the refrigerator and freezer compartments is ΔTr = Tr_current - Tr_on (Tr_on is the refrigerator compartment's start-up temperature, which is 6℃ in this embodiment). The temperature difference between the refrigerator and freezer compartments is ΔTf = Tf_current - Tf_on (Tf_on is the freezer compartment's start-up temperature, which is -18℃ in this embodiment). ΔTr is only valid when Tr_current ≥ Tr_on, and ΔTf is only valid when Tf_current ≥ Tf_on.

[0046] Determining the rate of temperature increase in a refrigerator: The rate of temperature increase is determined at the following times: Moment 1: Compressor start-up time; Time 2: When the refrigerator or freezer compartment requests cooling (i.e., the temperature in either compartment reaches the start-up point); Time 3: Every 9 minutes while the compressor is running.

[0047] First, determine if the refrigerator compartment is defrosting: if yes, do not use ΔTr for judgment; if no, determine if ΔTr > 4℃. Simultaneously, determine if the freezer compartment is defrosting: if yes, do not use ΔTf for judgment; if no, determine if ΔTf > 4℃.

[0048] Take the maximum value ΔTmax among all effective temperature differences.

[0049] If ΔTmax≤4℃, maintain the current rotational speed.

[0050] If ΔTmax > 4℃, record that the acceleration condition is met this time; When ΔTmax > 4℃ is satisfied twice consecutively (two adjacent judgment times), the speed is increased by 2 gears based on the initial speed gear.

[0051] For example, if the current ambient temperature is 25℃ and the initial speed is 5 (2400rpm), it will increase to 7 (3000rpm) after acceleration. Since the speed corresponding to 7 (3000rpm) is less than Smax (4320rpm), it will run in 7 (speed 7). It should be noted that if the intelligent noise reduction mode has just exited (less than 30 minutes ago), the temperature difference acceleration rule will not be executed this time.

[0052] Continuous running time acceleration determination: The continuous running time is accumulated in real time during compressor operation. It should be noted that if the compressor is currently in intelligent noise reduction mode, the running time in this mode is not included in the continuous running time; the timer will restart after exiting noise reduction mode.

[0053] When the continuous running time is ≥90 minutes and <120 minutes, shift up 2 gears based on the current speed and gear.

[0054] Example A: The current ambient temperature is 25℃, the initial speed is 5 (2400rpm), and there is no speed increase request due to room temperature rise during the cooling process. After speed increase, it becomes 7 (3000rpm). Example B: The current ambient temperature is 25℃, and the initial speed is 5 (2400rpm). The cooling process has already caused a speed increase due to the rise in room temperature. Therefore, the speed will be increased to 9 (3600rpm) on the basis of the speed increase of 7 (3000rpm), provided that it does not exceed the highest speed.

[0055] Example C: When the continuous running time is ≥120 minutes, the speed is adjusted to the highest level 12. Due to the limitation of Smax (4320rpm), the variable frequency compressor ultimately runs at 4320rpm.

[0056] Example 2: In summer, when a user uses the refrigerator, the ambient temperature in their home is 35°C. After purchasing a large amount of food, they put it into the refrigerator compartment all at once. At this time, the temperature difference ΔTr in the refrigerator compartment rises rapidly to more than 6°C. Two consecutive tests show that the conditions for speed increase are met, and the compressor speed increases from the initial level 7 (3000rpm) to level 9 (3600rpm), accelerating the cooling. If a large amount of food is put in, the compressor will continue to run and increase its speed for 90 minutes. However, due to the Smax limit, the refrigerator will eventually cool down to 4320rpm and then stop.

[0057] When the ambient temperature drops at night, the refrigerator's load decreases. The compressor operates at its initial speed or a lower speed, and the temperature difference ΔTmax does not exceed 4℃, thus avoiding speed increase and achieving energy-saving operation.

[0058] If the user activates the intelligent noise reduction mode at night, the compressor's maximum speed will be limited. The noise reduction mode will exit after 1 hour, and even if the temperature difference exceeds 4°C within 30 minutes after exiting, the compressor will not accelerate due to temperature difference to avoid sudden noise changes affecting the user's sleep.

[0059] The advantages of this embodiment include: 1. This embodiment uses two adjustment mechanisms, namely temperature difference acceleration and continuous running time acceleration, to dynamically adjust the compressor speed according to the real-time cooling load, thus overcoming the limitations of single-dimensional control.

[0060] 2. By using the judgment logic that the speed increase is only executed after the condition is met twice in a row, the speed increase caused by instantaneous fluctuations in the temperature sensor is avoided, thus ensuring the smoothness of speed adjustment.

[0061] 3. During defrosting, the temperature difference rate increase rule for the corresponding compartment is not implemented, thus avoiding energy waste caused by ineffective rate increase.

[0062] 4. The temperature difference acceleration rule will not be executed within 30 minutes after the noise cancellation mode is exited, to prevent sudden noise changes caused by immediate acceleration after the noise cancellation mode ends, thus improving the user experience.

[0063] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the discussion in some embodiments is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the contents of this disclosure, thereby enabling those skilled in the art to better utilize the embodiments.

Claims

1. A method for controlling the rotational speed of a variable frequency refrigerator, characterized in that, The method includes: The initial speed of the compressor is determined based on the ambient temperature; At a preset judgment time, the current temperature of at least one cooling room and the temperature difference between the current temperature and the start-up temperature corresponding to the current temperature are obtained, and the maximum temperature difference among all the temperature differences is used as the judgment basis; when the maximum temperature difference is greater than the first temperature difference threshold and the speed-up condition is met at least twice in a row, the compressor is increased from the initial speed by a first preset number of gears. The continuous operating time of the compressor is obtained; when the continuous operating time reaches a first preset time threshold, the speed of the compressor is increased from the current speed by a second preset number of gears; when the continuous operating time reaches the second preset time threshold, the speed of the compressor is set to the maximum speed limit; the second preset time threshold is greater than the first preset time threshold. The speed determined by the acceleration based on the room temperature difference and the speed determined by the acceleration based on the continuous running time are compared with the maximum speed limit, and the smaller value is taken as the final operating speed of the compressor.

2. The variable frequency refrigerator speed control method according to claim 1, characterized in that, The preset judgment time includes the time when the compressor starts, the time when any of the refrigeration rooms issues a refrigeration request, and the time every third preset time threshold when the compressor is running.

3. The variable frequency refrigerator speed control method according to claim 1, characterized in that, When any of the aforementioned cooling compartments is in defrost mode, the temperature difference of that compartment is not calculated, and the rate-up rule based on the temperature difference of that compartment is not executed.

4. The variable frequency refrigerator speed control method according to claim 1, characterized in that, The method also includes intelligent noise reduction mode processing, including: When the inverter refrigerator is operating in intelligent noise reduction mode, the maximum operating speed of the compressor is limited to be lower than the maximum speed limit; and within the fourth preset time threshold after exiting the intelligent noise reduction mode, the step of judging the room temperature difference acceleration is not executed.

5. The variable frequency refrigerator speed control method according to claim 4, characterized in that, When the compressor is in intelligent noise reduction mode, the recording of the compressor's continuous running time is paused, and the timing is restarted after exiting the intelligent noise reduction mode.

6. The variable frequency refrigerator speed control method according to claim 1, characterized in that, The first temperature difference threshold is 4℃, the first preset time threshold is 90 minutes, and the second preset time threshold is 120 minutes.

7. The variable frequency refrigerator speed control method according to claim 1, characterized in that, The process of determining the initial compressor speed based on ambient temperature includes: Obtain the ambient temperature of the environment where the inverter refrigerator is located; The initial speed is obtained by querying the ambient temperature-speed mapping table and the ambient temperature; different ambient temperature ranges correspond to different initial speed gears.

8. The variable frequency refrigerator speed control method according to claim 1, characterized in that, The method also includes speed gear conversion, including: Multiple speed gears are preset, and the speed value corresponding to each gear is calculated by multiplying the difference between the base speed and the gear number minus one by a preset coefficient; the maximum speed limit corresponds to the speed value of a non-integer gear.

9. The variable frequency refrigerator speed control method according to claim 1, characterized in that, The refrigeration compartment includes at least a refrigerator compartment and a freezer compartment; in the process of determining the rate of increase of the room temperature difference, the larger of the temperature difference of the refrigerator compartment and the temperature difference of the freezer compartment is taken as the maximum temperature difference.

10. A method for controlling the rotational speed of a variable frequency refrigerator according to claim 1, characterized in that, The temperature difference is the difference between the current temperature of the corresponding room and its start-up temperature when the current temperature of the refrigeration room is greater than or equal to its start-up temperature.

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