Frequency control method of air conditioner and air conditioner

Abstract

The application discloses a frequency control method of an air conditioner and the air conditioner, and relates to the technical field of air conditioners. The method comprises the following steps: acquiring a current frequency and a current low-pressure temperature during operation of the air conditioner in a frequency increasing state; determining a low-pressure temperature corresponding to the current frequency when the air conditioner operates in a first preset stable state, and marking the low-pressure temperature as a first low-pressure temperature; determining a low-pressure temperature corresponding to the current frequency when the air conditioner operates in a preset rated state, and marking the low-pressure temperature as a rated low-pressure temperature; judging whether the frequency increasing rate of the air conditioner is reasonable based on the first low-pressure temperature, the rated low-pressure temperature and the current low-pressure temperature; and if not, modifying the frequency of the compressor so that the frequency increasing rate of the air conditioner is within a reasonable range. The application can realize optimal starting frequency control, avoid protection shutdown caused by frequency fluctuation, improve the stability of air conditioner operation and improve user experience by adaptively modifying the frequency of the compressor when the frequency increasing rate is unreasonable, i.e. when the frequency increasing rate is too fast or too slow.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and more specifically, to a frequency control method for an air conditioner and an air conditioner. Background Technology

[0002] Multi-split air conditioners typically have complex systems and stringent control requirements. Therefore, precise control of compressor frequency upswing and downswing is crucial for stable air conditioner operation. Current compressor frequency control technology results in a rapid increase in compressor frequency after startup, which can lead to significant frequency fluctuations. In high-temperature environments, rapid cooling startup may cause excessive frequency rises and falls, leading to overshoot and protective shutdowns, thus reducing the stability of the air conditioner and negatively impacting the user experience. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a frequency control method and an air conditioner that can adaptively correct the compressor frequency when the frequency ramp-up rate is too fast or too slow. This enables optimal start-up frequency control, avoids frequency fluctuations that could lead to protective shutdowns, improves the stability of the air conditioner's operation, and enhances the user experience.

[0004] According to an embodiment of the present invention, a frequency control method for an air conditioner is provided, comprising: acquiring a current frequency and a current low-pressure temperature during operation of the air conditioner in a frequency-increasing state; determining the low-pressure temperature corresponding to the current frequency when the air conditioner is operating in a first preset stable state, and recording it as a first low-pressure temperature; determining the low-pressure temperature corresponding to the current frequency when the air conditioner is operating in a preset rated state, and recording it as a rated low-pressure temperature; determining whether the frequency increase rate of the air conditioner is reasonable based on the first low-pressure temperature, the rated low-pressure temperature, and the current low-pressure temperature; if not, correcting the compressor frequency to make the frequency increase rate of the air conditioner within a reasonable range.

[0005] By adopting the above technical solution, during the frequency increase process of the air conditioner, by calculating the first low-pressure temperature corresponding to the air conditioner under stable operation and the rated low-pressure temperature corresponding to the rated state, it is possible to accurately determine whether the air conditioner has a problem with an excessively fast frequency increase rate based on the current low-pressure temperature, the first low-pressure temperature, and the rated low-pressure temperature. By adaptively correcting the compressor frequency when the frequency increase rate of the air conditioner is unreasonable, that is, when the frequency increase rate is too fast or too slow, optimal start-up frequency control can be achieved, avoiding frequency fluctuations that lead to protection shutdown, improving the stability of air conditioner operation, and enhancing the user experience.

[0006] Preferably, the step of determining the low-pressure temperature corresponding to the current frequency when the air conditioner is operating in a preset stable state, and denoting it as the first low-pressure temperature, includes:

[0007] The low-pressure temperature corresponding to each compressor frequency of the air conditioner during operation in the first preset stable state is obtained; wherein, when the difference between the maximum and minimum low-pressure temperatures within a first preset time period is less than a first preset temperature difference, the air conditioner is determined to be in the first preset stable state; a function is fitted to each compressor frequency and the low-pressure temperature corresponding to the compressor frequency to obtain a functional relationship between the compressor frequency and the low-pressure temperature during operation in the first preset stable state, denoted as the first relationship; the first low-pressure temperature corresponding to the current frequency is determined based on the first relationship.

[0008] By adopting the above technical solution, a function fitting is performed on the compressor frequency and the low-pressure temperature corresponding to the compressor frequency under stable air condition operation. The relationship between frequency and low-pressure temperature when the compressor frequency does not fluctuate can be accurately obtained. By calculating the low-pressure temperature corresponding to the current frequency based on this relationship, accurate data can be provided for judging the current low-pressure temperature, thus improving the accuracy of compressor frequency control.

[0009] Preferably, the step of determining the low-pressure temperature corresponding to the current frequency of the air conditioner under a preset rated state, and denoting it as the rated low-pressure temperature, includes: obtaining a functional relationship between the rated compressor frequency of the air conditioner and the low-pressure temperature, denoted as the first rated relationship; and determining the rated low-pressure temperature corresponding to the current frequency based on the first rated relationship.

[0010] By adopting the above technical solution, the rated low-pressure temperature corresponding to the current frequency can be determined based on the rated factory default data, which can provide another accurate data basis for judging the current low-pressure temperature and improve the accuracy of low-pressure temperature judgment.

[0011] Preferably, the step of determining whether the frequency ramp-up rate of the air conditioner is reasonable based on the first low-pressure temperature, the rated low-pressure temperature, and the current low-pressure temperature, and correcting the compressor frequency if not, so that the frequency ramp-up rate of the air conditioner is within a reasonable range, includes: when the absolute value of the difference between the first low-pressure temperature and the rated low-pressure temperature is greater than the first temperature, and the current low-pressure temperature is greater than the first low-pressure temperature, controlling the compressor frequency to k1*f3; where 1 < k1, f3 is the functional relationship between the rated compressor frequency of the air conditioner and the low-pressure temperature, f3 = a3*Ps 2 +b3*Ps+c3, where a3, b3, and c3 are all constants, and Ps is the low-pressure temperature; when the absolute value of the difference between the first low-pressure temperature and the rated low-pressure temperature is greater than the first temperature, and the current low-pressure temperature is less than the first low-pressure temperature, the compressor frequency is controlled to be k2*f3; where 0 < k2 < 1.

[0012] By adopting the above technical solutions, when the current low-pressure temperature is too high, controlling the compressor frequency to k1*f3 can increase the compressor's frequency ramp-up rate, prevent the compressor from overheating and damaging the internal components, and improve the safety and stability of the compressor operation; when the low-pressure temperature is too low, controlling the compressor frequency to k2*f3 can reduce the compressor's frequency ramp-up rate, increase the low-pressure, prevent frost from forming on the condenser surface, and improve the cooling capacity.

[0013] Preferably, the frequency control method of the air conditioner further includes: when the absolute value of the difference between the first low-pressure temperature and the rated low-pressure temperature is less than the first temperature, and the absolute value of the difference between the current low-pressure temperature and the first low-pressure temperature is less than the first temperature, controlling the compressor frequency to f3.

[0014] By adopting the above technical solution, when the low-pressure temperature and the rated low-pressure temperature are close to the first low-pressure temperature, the compressor is controlled to maintain the current frequency ramp-up rate to ensure that the compressor frequency ramp-up rate is not too fast or too slow, thereby improving the reliability of compressor frequency control.

[0015] Preferably, the frequency control method for the air conditioner further includes: acquiring the current frequency and the current high-pressure temperature during the operation of the air conditioner in a frequency reduction state; determining the high-pressure temperature corresponding to the current frequency when the air conditioner is operating in a second preset stable state, and recording it as the first high-pressure temperature; determining the high-pressure temperature corresponding to the current frequency when the air conditioner is operating in a preset rated state, and recording it as the rated high-pressure temperature; judging whether the frequency reduction rate of the air conditioner is reasonable based on the first high-pressure temperature, the rated high-pressure temperature, and the current high-pressure temperature; if not, correcting the compressor frequency so that the frequency reduction rate of the air conditioner is within a reasonable range.

[0016] By adopting the above technical solution, monitoring the high-pressure temperature, and controlling the compressor frequency according to the high-pressure temperature during the compressor frequency reduction process, it can be ensured that the compressor operates within a safe and effective operating range.

[0017] Preferably, the step of determining the high-pressure temperature corresponding to the current frequency when the air conditioner is operating in a second preset stable state, denoted as the first high-pressure temperature, includes: obtaining the high-pressure temperature corresponding to each compressor frequency when the air conditioner is operating in the second preset stable state; wherein, when the difference between the maximum and minimum high-pressure temperatures within a second preset time period is less than a second preset temperature difference, the air conditioner is determined to be in the second preset stable state; performing function fitting on each compressor frequency and the high-pressure temperature corresponding to the compressor frequency to obtain a functional relationship between the compressor frequency and the high-pressure temperature when the air conditioner is operating in the second preset stable state, denoted as the second relationship; and determining the first high-pressure temperature corresponding to the current frequency based on the second relationship.

[0018] By adopting the above technical solution, a function fitting is performed on the compressor frequency and the high-pressure temperature corresponding to the compressor frequency under stable air condition operation. The relationship between frequency and high-pressure temperature when the compressor frequency does not fluctuate can be accurately obtained. By calculating the high-pressure temperature corresponding to the current frequency based on this relationship, accurate data can be provided for judging the current high-pressure temperature, thereby improving the accuracy of compressor frequency control.

[0019] Preferably, the step of determining the high-pressure temperature corresponding to the current frequency of the air conditioner under a preset rated state, and denoting it as the rated high-pressure temperature, includes: obtaining the functional relationship between the rated compressor frequency of the air conditioner and the high-pressure temperature, denoted as the second rated relationship; and determining the rated high-pressure temperature corresponding to the current frequency based on the second rated relationship.

[0020] By adopting the above technical solution, the rated high-voltage temperature corresponding to the current frequency can be determined based on the rated factory default data, which can provide another accurate data basis for judging the current high-voltage temperature and improve the accuracy of high-voltage temperature judgment.

[0021] Preferably, the step of determining whether the frequency reduction rate of the air conditioner is reasonable based on the first high-pressure temperature, the rated high-pressure temperature, and the current high-pressure temperature, and correcting the compressor frequency if not, so that the frequency reduction rate of the air conditioner is within a reasonable range, includes: when the absolute value of the difference between the first high-pressure temperature and the rated high-pressure temperature is greater than a second temperature, and the current high-pressure temperature is greater than the first high-pressure temperature, controlling the compressor frequency to k3*f4; where 1 < k3, f4 is the functional relationship between the rated compressor frequency of the air conditioner and the high-pressure temperature, f4 = a4*Pd 2+b4*Pd+c4, where a4, b4, and c4 are constants, and Pd is the high-pressure temperature; when the absolute value of the difference between the first high-pressure temperature and the rated high-pressure temperature is greater than the second temperature, and the current high-pressure temperature is less than the first high-pressure temperature, the compressor frequency is controlled to be k4*f4; where 0 < k4 < 1; when the absolute value of the difference between the first high-pressure temperature and the rated high-pressure temperature is less than the second temperature, and the absolute value of the difference between the current high-pressure temperature and the first high-pressure temperature is less than the second temperature, the compressor frequency is controlled to be f4.

[0022] By adopting the above technical solutions, when the current high-pressure temperature is too high, controlling the compressor frequency to k3*f4 can increase the compressor's frequency ramp-up rate, avoid compressor overload causing temperature rise, reduce the compressor's operating load, and improve the safety and stability of compressor operation. When the high-pressure pressure is too low, controlling the compressor frequency to k4*f4 can reduce the compressor's frequency ramp-up rate, increase the high-pressure pressure, improve the air conditioner's cooling capacity, and enhance the user experience. When the high-pressure temperature and the rated high-pressure temperature are close to the first high-pressure temperature, controlling the compressor to maintain the current frequency ramp-down rate ensures that the compressor's frequency ramp-down rate is not too fast or too slow, improving the reliability of compressor frequency control.

[0023] According to an embodiment of the present invention, another aspect provides an air conditioner including a computer-readable storage medium storing a computer program and a processor, the computer program being read and executed by the processor to implement the method as described in any of the first aspects.

[0024] The present invention has the following beneficial effects: By calculating the first low-pressure temperature corresponding to the air conditioner under stable operation and the rated low-pressure temperature corresponding to the rated state during the frequency increase process of the air conditioner, it is possible to accurately determine whether the air conditioner has a problem of excessive frequency increase rate based on the current low-pressure temperature, the first low-pressure temperature and the rated low-pressure temperature. By adaptively correcting the compressor frequency when the frequency increase rate of the air conditioner is unreasonable, that is, when the frequency increase rate is too fast or too slow, the optimal start-up frequency control can be achieved, avoiding frequency fluctuations that lead to protection shutdown, improving the stability of air conditioner operation and enhancing user experience. Attached Figure Description

[0025] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0026] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0027] Figure 1 A flowchart of a frequency control method for an air conditioner provided by the present invention. Detailed Implementation

[0028] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] This embodiment provides a frequency control method for an air conditioner, which can be applied to air conditioners, see below. Figure 1 The flowchart of the frequency control method for the air conditioner shown mainly includes the following steps S102 to S108:

[0031] Step S102: During the operation of the air conditioner in frequency up mode, obtain the current frequency and the current low-pressure temperature.

[0032] The air conditioner mentioned above can be a multi-split air conditioner. When the air conditioner is a multi-split air conditioner, the load rate of the multi-split air conditioner is 100%. The load rate is the ratio of the total horsepower of the indoor units to the total horsepower of the outdoor units. A load rate of 100% means that all indoor units are running.

[0033] When the air conditioner is operating in a frequency-increasing state, such as when the air conditioner starts up and the compressor frequency gradually increases, the air conditioner is operating in a frequency-increasing state. Based on the temperature sensor, the low-pressure temperature is detected in real time, and the current frequency and current low-pressure temperature of the compressor are obtained in real time or periodically.

[0034] Step S104: Determine the low-pressure temperature corresponding to the current frequency when the air conditioner is running in the first preset stable state, and record it as the first low-pressure temperature.

[0035] The aforementioned first preset stable state refers to the air conditioner operating at a stable frequency increase. In this state, the low-pressure temperature will not fluctuate, and consequently, the compressor frequency will not fluctuate drastically. By obtaining the functional relationship between the compressor frequency and the low-pressure temperature when the air conditioner is operating in this first preset stable state, and outputting this functional relationship with the obtained current compressor frequency, the corresponding low-pressure temperature when the air conditioner is operating in this first preset stable state can be obtained, denoted as the first low-pressure temperature.

[0036] Step S106: Determine the low-pressure temperature corresponding to the current frequency of the air conditioner under the preset rated state, and record it as the rated low-pressure temperature.

[0037] The above-mentioned preset rated state is the relationship between the compressor's rated frequency and low-pressure temperature as defaulted to the factory settings of the air conditioner. The low-pressure temperature corresponding to the rated frequency that is equal to the current frequency of the compressor is taken as the rated low-pressure temperature corresponding to the air conditioner when it is running in the rated state.

[0038] Step S108: Based on the first low-pressure temperature, the rated low-pressure temperature and the current low-pressure temperature, determine whether the frequency increase rate of the air conditioner is reasonable. If not, correct the compressor frequency so that the frequency increase rate of the air conditioner is within a reasonable range.

[0039] The inventors discovered that when the low-pressure temperature is too low, it may lead to excessive cooling or excessive refrigerant entering the compressor, increasing the compressor's load. To avoid this, the compressor may reduce its operating frequency to control the low-pressure temperature. When the air conditioner is first started, the high-pressure temperature does not rise rapidly; it is a gradual heating process. By detecting the low-pressure temperature during the compressor's frequency increase and controlling the compressor frequency accordingly, it can be ensured that the compressor load is not excessive.

[0040] Compare the current low-pressure temperature with the rated low-pressure temperature and the first low-pressure temperature. If the current low-pressure temperature is too low, it indicates that the compressor's frequency ramp-up rate is too fast, which may cause frost to form on the condenser surface, resulting in lower cooling capacity. Reduce the compressor's frequency ramp-up rate. If the actual detected current low-pressure temperature is too high, it indicates that the compressor's frequency ramp-up rate is too slow, which may cause the compressor to overheat and damage internal compressor components. Control the compressor's frequency ramp-up rate to increase in order to avoid damaging the compressor.

[0041] The frequency control method for air conditioners provided in this embodiment calculates the first low-pressure temperature and the rated low-pressure temperature under stable operation and rated conditions during the frequency ramp-up process. Based on the current low-pressure temperature, the first low-pressure temperature, and the rated low-pressure temperature, it can accurately determine whether the air conditioner has an excessively fast frequency ramp-up rate. By adaptively correcting the compressor frequency when the frequency ramp-up rate is unreasonable (i.e., too fast or too slow), optimal start-up frequency control can be achieved, avoiding frequency fluctuations that could lead to protection shutdown, thus improving the stability of air conditioner operation and enhancing the user experience.

[0042] In one embodiment, this embodiment provides an implementation method for determining the low-pressure temperature corresponding to the current frequency when the air conditioner is running in a preset stable state, denoted as the first low-pressure temperature. The specific steps are as follows:

[0043] Step (1): Obtain the low-pressure temperature corresponding to each compressor frequency when the air conditioner is running in the first preset stable state.

[0044] In one specific implementation, when the difference between the maximum and minimum low-pressure temperatures within a first preset time period is less than a first preset temperature difference, the air conditioner is determined to be in a first preset stable state. The first preset time period can range from 5 to 15 minutes, with a preferred value of 10 minutes. The first preset temperature difference can range from 0 to 2°C, with a preferred value of 1°C.

[0045] When the air conditioner is in stable operation, the compressor frequency and its corresponding low-pressure temperature are sampled to obtain multiple sets of coordinates, namely, the compressor frequency and the low-pressure temperature corresponding to each compressor frequency. For example, if the air conditioner is running at frequency f1, and the change in low-pressure temperature Ps over 10 consecutive minutes is |Psmax-Psmin|=△Ts<1℃, it is considered to be in stable operation. Assuming the compressor frequency increases from 0Hz to 100Hz, the sampling interval of the compressor frequency can be set to 5, that is, the increase in frequency is controlled at 5Hz each time (5Hz, 10Hz, 15Hz, 20Hz...), thus obtaining multiple sets of coordinate values.

[0046] Step (2): Perform function fitting on each compressor frequency and the low-pressure temperature corresponding to the compressor frequency to obtain the functional relationship between the compressor frequency and the low-pressure temperature when the air conditioner is running in the first preset stable state, which is denoted as the first relationship.

[0047] When the air conditioner is running stably, the load changes little, and there is an approximately linear relationship between the compressor frequency and the low-pressure temperature. Therefore, based on the coordinate values ​​formed by multiple sets of compressor frequencies and the corresponding low-pressure temperatures, a linear function is fitted to obtain the functional relationship between the compressor frequency and the low-pressure temperature, which is denoted as the first relationship.

[0048] In one specific implementation, the aforementioned first relationship can be a linear function, such as f1 = a1 * Ps + b1. a1 and b1 are constants, f1 is the compressor frequency, and Ps is the low-pressure temperature.

[0049] Step (3): Determine the first low-pressure temperature corresponding to the current frequency based on the first relational formula.

[0050] By inputting the compressor's current frequency into the first relational formula in real time or periodically, the first low-pressure temperature Ps1 corresponding to the current frequency can be obtained, which is the low-pressure temperature value that the compressor frequency should correspond to when the air conditioner is running in a stable state.

[0051] By fitting a function to the compressor frequency and the corresponding low-pressure temperature under stable air conditioning operation, the relationship between frequency and low-pressure temperature when the compressor frequency does not fluctuate can be accurately obtained. By calculating the low-pressure temperature corresponding to the current frequency based on this relationship, accurate data can be provided for judging the current low-pressure temperature, thus improving the accuracy of compressor frequency control.

[0052] In one embodiment, this embodiment provides a specific implementation method for determining the low-pressure temperature corresponding to the current frequency of an air conditioner under a preset rated state, denoted as the rated low-pressure temperature: obtaining the functional relationship between the rated compressor frequency and the low-pressure temperature of the air conditioner, denoted as the first rated relationship; and determining the rated low-pressure temperature corresponding to the current frequency based on the first rated relationship.

[0053] Obtain the actual factory default operating data of the air conditioner, that is, obtain the functional relationship between the compressor frequency and the low-pressure temperature recorded in the air conditioner's rated parameter information when the air conditioner is turned on or when the frequency is increased due to protection control. This is denoted as the first rated relationship. Input the current frequency of the compressor into the above first rated relationship to calculate the low-pressure temperature corresponding to the current frequency, which is denoted as the rated low-pressure temperature Ps2.

[0054] In one specific implementation, the compressor frequency in the air conditioner's default factory data can have an approximate quadratic function relationship with the low-pressure temperature. The aforementioned first rated relationship can be: f3 = a3 * Ps 2 +b3*Ps+c3, where a3, b3, and c3 are all constants, and Ps is the low-pressure temperature.

[0055] By determining the rated low-pressure temperature corresponding to the current frequency based on the rated factory default data, another accurate data basis can be provided for judging the current low-pressure temperature, thus improving the accuracy of low-pressure temperature judgment.

[0056] In one embodiment, this embodiment provides an implementation manner for judging whether the frequency increase rate of the air conditioner is reasonable based on the first low-pressure temperature, the rated low-pressure temperature, and the current low-pressure temperature. If not, the compressor frequency is corrected to make the frequency increase rate of the air conditioner within a reasonable range. The specific steps can be executed as follows:

[0057] Step 1): When the absolute value of the difference between the first low-pressure temperature Ps1 and the rated low-pressure temperature Ps2 is greater than the first temperature, and the current low-pressure temperature Ps is greater than the first low-pressure temperature, control the compressor frequency to be k1*f3;

[0058] Where, 1 < k1, and f3 is the functional relationship between the rated compressor frequency of the air conditioner and the low-pressure temperature, f3 = a3*Ps 2 + b3*Ps + c3, where a3, b3, and c3 are all constants, and Ps is the low-pressure temperature.

[0059] The value range of the above first temperature d1 can be 1 to 4°C. If |Ps2 - Ps1| > d1, it indicates that the current factory default frequency increase rate is inappropriate, and the air conditioner cannot operate stably at this factory default frequency increase rate, and the relationship between the compressor frequency and the low-pressure temperature needs to be corrected.

[0060] When the air conditioner is operating at an increasing frequency, it usually controls the frequency increase rate of the compressor according to the relationship between the factory default compressor frequency and the low-pressure temperature f3 = a3*Ps 2 + b3*Ps + c3. When Ps > Ps1, it indicates that the current low-pressure temperature is too high. Control the compressor frequency to be f3' = k1*f3, that is, increase the frequency increase rate of the compressor, and use f3' as the default frequency increase rate until the frequency increase rate of the air conditioner is within a reasonable range, that is, until |Ps2 - Ps1| < d1 is satisfied.

[0061] When Ps > Ps1, it indicates that the current low-pressure temperature is too high and the frequency increase rate is too slow, and the residence time of the refrigerant on the low-pressure side increases. By controlling the compressor frequency to be k1*f3 when the current low-pressure temperature is too high, the frequency increase rate of the compressor can be increased, avoiding overheating of the compressor during operation and damaging the internal components of the compressor, and improving the safety and stability of the compressor operation.

[0062] Step 2): When the absolute value of the difference between the first low-pressure temperature and the rated low-pressure temperature is greater than the first temperature, and the current low-pressure temperature is less than the first low-pressure temperature, control the compressor frequency to be k2*f3; where, 0 < k2 < 1.

[0063] If |Ps2 - Ps1| > d1, and Ps < Ps1, it indicates that the current factory default frequency increase rate is inappropriate, and the air conditioner cannot operate stably at this factory default frequency increase rate, and the relationship between the compressor frequency and the low-pressure temperature needs to be corrected.

[0064] When Ps < Ps1, it indicates that the current low-pressure temperature is too low. Control the frequency of the compressor as f3’ = k2 * f3, that is, reduce the frequency increase rate of the compressor, and use f3’ as the default frequency increase rate until the frequency increase rate of the air conditioner is within a reasonable range, that is, until |Ps2 - Ps1| < d1 is satisfied.

[0065] When Ps < Ps1, it indicates that the current low-pressure temperature is too low and the frequency increase rate of the compressor is too fast. The residence time of the refrigerant on the low-pressure side is reduced, the low-pressure pressure and temperature drop. The low-pressure temperature is closely related to the pressure of the refrigerant, which may cause frosting on the surface of the condenser and result in low refrigeration capacity. By controlling the compressor frequency to k2 * f3 when the low-pressure pressure is too low, the frequency increase rate of the compressor can be reduced, the low-pressure pressure can be increased, frosting on the surface of the condenser can be avoided, and the refrigeration capacity can be improved.

[0066] Step 3): When the absolute value of the difference between the first low-pressure temperature and the rated low-pressure temperature is less than the first temperature, and the absolute value of the difference between the current low-pressure temperature and the first low-pressure temperature is less than the first temperature, control the compressor frequency as f3.

[0067] If |Ps2 - Ps1| < d1 and |Ps - Ps1| < d1, it indicates that the actual frequency increase rate is relatively close to the frequency increase rate under the stable operation state and the factory default. The factory default frequency increase rate is more appropriate. Control the compressor frequency based on the factory default frequency increase rate f3, that is, maintain the relational expression between the factory default compressor frequency and the low-pressure temperature.

[0068] By controlling the compressor to maintain the current frequency increase rate when the low-pressure temperature and the rated low-pressure temperature are close to the first low-pressure temperature, it is ensured that the frequency increase rate of the compressor will not be too fast or too slow, and the reliability of the compressor frequency control is improved.

[0069] In one embodiment, to prevent the compressor frequency decrease rate from being too fast or too slow, the method provided in this embodiment further includes the following steps:

[0070] Step a, during the operation of the air conditioner in the frequency decrease state, obtain the current frequency and the current high-pressure temperature.

[0071] During the operation of the air conditioner in the frequency decrease state, the high-pressure temperature is detected in real time based on the temperature sensor, or the high-pressure saturation temperature is determined according to the high-pressure pressure, and the current frequency and the current high-pressure temperature of the compressor are obtained in real time or periodically.

[0072] Step b, determine the high-pressure temperature corresponding to the current frequency when the air conditioner is operating in the second preset stable state, and denote it as the first high-pressure temperature.

[0073] The second preset stable state is when the air conditioner is in a stable reduced-frequency operation state, in which the high-pressure temperature will not fluctuate, and thus the compressor frequency will not fluctuate drastically.

[0074] In one specific implementation, the high-pressure temperature corresponding to each compressor frequency during the operation of the air conditioner in a second preset stable state is obtained; wherein, when the difference between the maximum and minimum high-pressure temperatures within a second preset time period is less than the second preset temperature difference, the air conditioner is determined to be in the second preset stable state; the first preset time period can be in the range of 5 to 15 minutes, preferably 10 minutes. The second preset temperature difference can be in the range of 0 to 2°C, preferably 1°C.

[0075] By fitting a function to each compressor frequency and the high-pressure temperature corresponding to the compressor frequency, the functional relationship between the compressor frequency and the high-pressure temperature when the air conditioner is running in the second preset stable state is obtained, which is denoted as the second relationship.

[0076] The first high-pressure temperature corresponding to the current frequency is determined based on the second relation.

[0077] When the air conditioner is in stable operation, the compressor frequency and its corresponding high-pressure temperature are sampled to obtain multiple sets of coordinates, namely, the compressor frequency and the high-pressure temperature corresponding to each compressor frequency. For example, if the compressor frequency decreases from 100Hz to 0Hz, the sampling interval of the compressor frequency can be set to 5, that is, each decrease is controlled at 5Hz (100Hz, 95Hz, 90Hz, 85Hz, etc.), thereby obtaining multiple sets of coordinate values.

[0078] When the air conditioner is running stably, the load changes little, and there is an approximately linear relationship between the compressor frequency and the high-pressure temperature. Therefore, a linear function is fitted based on the coordinate values ​​formed by multiple sets of compressor frequencies and the high-pressure temperatures corresponding to the compressor frequencies to obtain the functional relationship between the compressor frequency and the high-pressure temperature, which is denoted as the second relationship.

[0079] In one specific implementation, the second relationship described above can be a linear function, such as f2 = a2 * Pd + b2. a2 and b2 are constants, f2 is the compressor frequency, and Pd is the high-pressure temperature.

[0080] By inputting the current frequency of the compressor, which is obtained in real time or periodically, into the second relational expression mentioned above, the first high-pressure temperature Pd1 corresponding to the current frequency can be obtained. That is, when the air conditioner is running in a stable state, the high-pressure temperature value that the compressor frequency should correspond to at this time can be obtained.

[0081] By fitting a function to the compressor frequency and the corresponding high-pressure temperature under stable air conditioning operation, the relationship between frequency and high-pressure temperature when the compressor frequency is stable can be accurately obtained. By calculating the high-pressure temperature corresponding to the current frequency based on this relationship, accurate data can be provided for judging the current high-pressure temperature, thus improving the accuracy of compressor frequency control.

[0082] Step c: Determine the high-pressure temperature corresponding to the current frequency of the air conditioner under preset rated conditions, and record it as the rated high-pressure temperature.

[0083] In one specific implementation, the functional relationship between the rated compressor frequency and the high-pressure temperature of the air conditioner is obtained and denoted as the second rated relationship; the rated high-pressure temperature corresponding to the current frequency is determined based on the second rated relationship.

[0084] Obtain the actual factory default operating data of the air conditioner, that is, obtain the functional relationship between the compressor frequency and high-pressure temperature recorded in the air conditioner's rated parameter information when the air conditioner is reducing its frequency, denoted as the second rated relationship. Input the current frequency of the compressor into the above second rated relationship to calculate the high-pressure temperature corresponding to the current frequency, denoted as the rated high-pressure temperature Pd2.

[0085] In one specific implementation, the compressor frequency in the air conditioner's default factory data can have an approximate quadratic function relationship with the high-pressure temperature. The aforementioned second rated relationship can be: f4=a4*Pd 2 +b4*Pd+c4, where a4, b4, and c4 are all constants, and Pd is the high-pressure temperature.

[0086] By determining the rated high-voltage temperature corresponding to the current frequency based on the factory default data, another accurate data basis can be provided for judging the current high-voltage temperature, thus improving the accuracy of high-voltage temperature judgment.

[0087] Step d: Based on the first high-pressure temperature, the rated high-pressure temperature, and the current high-pressure temperature, determine whether the frequency reduction rate of the air conditioner is reasonable. If not, correct the compressor frequency so that the frequency reduction rate of the air conditioner is within a reasonable range.

[0088] Compare the current high-pressure temperature with the rated high-pressure temperature and the first high-pressure temperature. If the current high-pressure temperature is too low, it indicates that the compressor's frequency ramp-up rate is too fast, resulting in a significant decrease in cooling capacity. Control the compressor's frequency ramp-up rate to decrease. If the actual detected current high-pressure temperature is too high, it indicates that the compressor's frequency ramp-up rate is too slow, which may cause the compressor to overload and run at high load due to rising compressor temperature. Control the compressor's frequency ramp-up rate to increase to avoid damaging the compressor.

[0089] In a specific embodiment, when the absolute value of the difference between the first high-pressure temperature Pd1 and the rated high-pressure temperature Pd2 is greater than the second temperature, and the current high-pressure temperature is greater than the first high-pressure temperature, the compressor frequency is controlled to be k3*f4; where 1 < k3, and f4 is the functional relationship between the rated compressor frequency of the air conditioner and the high-pressure temperature, f4 = a4*Pd 2 +b4*Pd + c4, where a4, b4, and c4 are all constants, and Pd is the high-pressure temperature;

[0090] The value range of the above-mentioned second temperature d2 can be 3 to 7°C. If |Pd2 - Pd1| > d2, it indicates that the current factory default frequency reduction rate is inappropriate, and the air conditioner cannot operate stably at this factory default frequency reduction rate, and the relationship between the compressor frequency and the high-pressure temperature needs to be corrected.

[0091] When the air conditioner operates at a reduced frequency, it usually controls the frequency reduction rate of the compressor according to the relationship between the factory default compressor frequency and the high-pressure temperature f4 = a4*Pd 2 +b4*Pd + c4. If the current high-pressure temperature Pd > Pd1, it indicates that the current high-pressure temperature is too high, and the compressor frequency is controlled to be f4' = k3*f4, that is, the frequency increase rate of the compressor is increased, and f4' is used as the default frequency reduction rate until the frequency reduction rate of the air conditioner is within a reasonable range, that is, until |Pd2 - Pd1| < d2 is satisfied.

[0092] When Pd > Pd1, it indicates that the current high-pressure temperature is too high and the frequency increase rate is too slow, which is likely to cause the compressor to operate overloaded. By controlling the compressor frequency to be k3*f4 when the current high-pressure temperature is too high, the frequency increase rate of the compressor can be increased, avoiding the temperature rise caused by the compressor operating overloaded, reducing the operating load of the compressor, and improving the safety and stability of the compressor operation.

[0093] When the absolute value of the difference between the first high-pressure temperature and the rated high-pressure temperature is greater than the second temperature, and the current high-pressure temperature is less than the first high-pressure temperature, the compressor frequency is controlled to be k4*f4; where 0 < k4 < 1;

[0094] If |Pd2 - Pd1| > d2 and Pd < Pd1, it indicates that the current factory default frequency reduction rate is inappropriate, and the air conditioner cannot operate stably at this factory default frequency reduction rate, and the relationship between the compressor frequency and the high-pressure temperature needs to be corrected.

[0095] When Pd < Pd1, it indicates that the current high-pressure temperature is too low, and the compressor frequency is controlled to be f4' = k4*f4, that is, the frequency reduction rate of the compressor is reduced, and f4' is used as the default frequency reduction rate until the frequency reduction rate of the air conditioner is within a reasonable range, that is, until |Pd2 - Pd1| < d2 is satisfied.

[0096] When Pd < Pd1, it indicates that the current high-pressure temperature is too low, the frequency increase rate of the compressor is too fast, and the refrigeration capacity decreases significantly. By controlling the compressor frequency to k4*f4 when the high-pressure is too low, the frequency increase rate of the compressor can be reduced, the high-pressure is increased, the refrigeration capacity of the air conditioner is improved, and the user experience is enhanced.

[0097] When the absolute value of the difference between the first high-pressure temperature and the rated high-pressure temperature is less than the second temperature, and the absolute value of the difference between the current high-pressure temperature and the first high-pressure temperature is less than the second temperature, control the compressor frequency to f4.

[0098] If |Pd2 - Pd1| < d2 and |Pd - Pd1| < d2, it indicates that the actual frequency decrease rate is relatively close to the frequency decrease rate in the stable operation state and the factory default, and the factory default frequency decrease rate is appropriate. Control the compressor frequency based on the factory default frequency decrease rate f4, that is, maintain the relational expression between the factory default compressor frequency and the high-pressure temperature.

[0099] By controlling the compressor to maintain the current frequency decrease rate when the high-pressure temperature and the rated high-pressure temperature are close to the first high-pressure temperature, it is ensured that the frequency decrease rate of the compressor is neither too fast nor too slow, and the reliability of the compressor frequency control is improved.

[0100] The inventor's research found that when the compressor frequency decreases, its exhaust pressure decreases, and the corresponding high-pressure temperature decreases. The high-pressure temperature is a parameter directly related to the compressor performance. If the high-pressure temperature (i.e., the high-pressure saturation temperature) is too high, it may cause the compressor to overheat and be damaged, while too low high-pressure temperature may affect its refrigeration effect. By monitoring the high-pressure temperature and controlling the compressor frequency according to the high-pressure temperature during the compressor frequency decrease process, it can be ensured that the compressor operates within a safe and effective working range.

[0101] The frequency control method of the air conditioner provided in this embodiment can solve the problem of over-adjustment of the compressor frequency and improve the reliability of the compressor frequency control by controlling the frequency increase rate of the compressor according to the low-pressure temperature and controlling the frequency decrease rate of the compressor according to the high-pressure temperature.

[0102] Corresponding to the frequency control method of the air conditioner provided in the above embodiment, the embodiment of the present invention provides an example of controlling the frequency of the air conditioner compressor by applying the above frequency control method of the air conditioner. The specific steps can be executed as follows:

[0103] Step 1, obtain the stable operation data of the air conditioner;

[0104] For a given air conditioner, assuming a fixed total amount of refrigerant in the system, and under a defined frequency and ambient temperature, the load rate is constant (this example considers a 100% load rate), and the high-pressure and low-pressure temperatures are also constant. That is, the frequency f is related to the low-pressure temperature Ps and the high-pressure temperature Pd. When the air conditioner's load changes little and its operation is relatively stable, the compressor frequency has an approximately linear relationship with both the high-pressure and low-pressure temperatures.

[0105] 1) When the air conditioner is running stably under normal environmental conditions, during the compressor frequency f1 (0→fm) frequency increase process, the corresponding low-pressure temperature Ps1 is obtained. By collecting the low-pressure temperature corresponding to each compressor frequency under stable operating conditions, the relationship between frequency and low-pressure temperature is obtained as: f1=a1*Ps1+b1 (a1 and b1 are constants).

[0106] When the low-pressure temperature is too low, it may cause excessive cooling or excessive refrigerant to enter the compressor, increasing the compressor load. To avoid this, the compressor may reduce its operating frequency to control the low-pressure temperature. When the air conditioner starts, the high-pressure temperature rises slowly, which is a gradual heating process. By detecting the low-pressure temperature during the frequency increase process, it can be ensured that the compressor load is not too high.

[0107] Determining whether an air conditioner is operating stably: When the air conditioner is running at frequency f1, if the change in low-pressure temperature Ps over a continuous 10-minute period is |Psmax-Psmin|=△Ps<1℃, then the air conditioner is considered to be operating stably.

[0108] If the compressor frequency increases from 0Hz to 100Hz, the sampling interval of the compressor frequency can be set to 5, that is, the speed-up is controlled at 5Hz each time (5Hz, 10Hz, 15Hz, 20Hz...), thus obtaining multiple sets of coordinate values.

[0109] 2) When the air conditioner operates stably under normal environmental conditions, during the compressor frequency reduction process f2 (fm→0), the corresponding high-pressure temperature Pd1 is obtained. By collecting the high-pressure temperature corresponding to each compressor frequency under stable operating conditions, the relationship between frequency and high-pressure temperature is derived: f2=a2*Pd1+b2 (a2 and b2 are constants).

[0110] When the compressor reduces its frequency, the discharge pressure decreases, and the corresponding high-pressure temperature also decreases. High-pressure temperature is directly related to compressor performance; by monitoring and controlling it, we can ensure the compressor operates within a safe and efficient range. Excessively high high-pressure temperature may cause the compressor to overheat and be damaged, while excessively low high-pressure temperature may affect cooling performance.

[0111] Set the compressor frequency to decrease from 100 Hz to 0 Hz, and the sampling interval of the compressor frequency can be set to 5, that is, the speed reduction each time is controlled at 5 Hz (100 Hz, 95 Hz, 90 Hz, 85 Hz...), so as to obtain multiple groups of coordinate values.

[0112] Step 2, obtain the actual factory default operating data

[0113] During the process of the air conditioner starting up or triggering protection control to reduce frequency, there is approximately a quadratic relationship between the compressor frequency, the high-pressure temperature, and the low-pressure temperature.

[0114] 1) The air conditioner operates at a rising frequency freely when starting up at the ambient temperature Tao, with the operating frequency f3 (0 → fm), corresponding to the low-pressure temperature Ps2. Obtain the instantaneous low-pressure temperature at the moment when the actual operating frequency reaches f3, and obtain the relationship between the frequency and the low-pressure temperature: f3 = a3 * Ps2 2 + b3 * Ps2 + c3, where a3, b3, and c3 are constants.

[0115] For example, when f3 reaches 60 Hz, record the low-pressure temperature corresponding to 60 Hz, which is denoted as the rated low-pressure temperature.

[0116] 2) After the air conditioner reaches fm at the ambient temperature Tao, it operates at a decreasing frequency, with the operating frequency f4 (fm → 0). Obtain the instantaneous low-pressure temperature at the moment when the actual operating frequency reaches f3, corresponding to the high-pressure temperature Pd2, and obtain the relationship between the frequency and the high-pressure temperature: f4 = a4 * Pd2 2 + b4 * Pd2 + c4, where a4, b4, and c4 are constants.

[0117] For example, when f4 reaches 70 Hz, record the high-pressure temperature corresponding to 70 Hz, which is denoted as the rated high-pressure temperature.

[0118] Step 3, during the process of the air conditioner operating at a rising frequency, detect the current low-pressure temperature and the current frequency of the compressor;

[0119] Input the current frequency into f1 and f3 respectively, and obtain the first low-pressure temperature Ps1 corresponding to the current frequency in f1, and the rated low-pressure temperature Ps2 corresponding to the current frequency in f3.

[0120] If |Ps2 - Ps1| < d1 and |Ps - Ps1| < d1, it indicates that the actual rising frequency rate is relatively close to the rising frequency rate in the stable operating state and the factory default, and the factory default rising frequency rate is more appropriate. Continue to control the compressor frequency based on the factory default rising frequency rate f3, that is, maintain the relationship between the factory default compressor frequency and the low-pressure temperature.

[0121] If |Ps2 - Ps1| > d1, it indicates that the current factory default rising frequency rate is not appropriate, and the relationship between the compressor frequency and the low-pressure temperature needs to be corrected.

[0122] If |Ps2 - Ps1| > d1 and Ps > Ps1, it indicates that the low-pressure temperature is too high and the frequency increase rate is too slow during the actual operation. The residence time of the refrigerant on the low-pressure side increases, and there is more heat exchange, which will cause the compressor to operate overheat and damage the internal components of the compressor. The relationship between the corrected compressor frequency and the low-pressure temperature is: f3’ = k1 * f3, where 1 < k1 < 2, that is, the frequency increase rate is increased, and f3’ is used as the default frequency increase rate until |Ps2 - Ps1| < d1.

[0123] If |Ps2 - Ps1| > d1 and Ps < Ps1, it indicates that the low-pressure temperature is too low and the frequency increase rate is too fast during the actual operation. The residence time of the refrigerant on the low-pressure side decreases, and the low-pressure pressure and temperature will drop. Since the low-pressure temperature is closely related to the pressure of the refrigerant, it may cause frosting on the surface of the condenser, resulting in lower refrigeration capacity. The relationship between the corrected compressor frequency and the low-pressure temperature is: f3’ = k2 * f3, where 0 < k2 < 1, that is, the frequency increase rate is decreased, and f3’ is used as the default frequency increase rate until |Ps2 - Ps1| < d1.

[0124] Step 4, during the frequency reduction operation of the air conditioner, detect the current high-pressure temperature and the current frequency of the compressor.

[0125] Input the current frequency into f2 and f4 respectively above to obtain the first high-pressure temperature Pd1 corresponding to the current frequency in f2 and the rated high-pressure temperature Pd2 corresponding to the current frequency in f4.

[0126] If |Pd2 - Pd1| < d2 and |Pd - Pd1| < d2, it indicates that the actual frequency reduction rate is relatively close to the frequency reduction rate under the stable operation state and the factory default. The factory default frequency reduction rate is more appropriate. Control the compressor frequency based on the factory default frequency reduction rate f4, that is, maintain the relationship formula between the factory default compressor frequency and the high-pressure temperature.

[0127] If |Pd2 - Pd1| > d2, it indicates that the current factory default frequency reduction rate is inappropriate and the relationship between the compressor frequency and the high-pressure temperature needs to be corrected.

[0128] If |Pd2 - Pd1| > d2 and Pd > Pd1, it indicates that the high-pressure temperature is too high and the frequency increase rate is too slow during the actual operation, which will cause the compressor to be overloaded, increase the compressor temperature, and operate at a high load. The relationship between the corrected compressor frequency and the high-pressure temperature is: f4’ = k3 * f4, where 1 < k3 < 2, that is, the frequency reduction rate is increased, and f4’ is used as the default frequency reduction rate until |Pd2 - Pd1| < d2.

[0129] If |Pd2 - Pd1| > d2 and Pd < Pd1, it indicates that the high-pressure temperature is too low and the frequency reduction rate is too fast during the actual operation process, which will lead to a significant decrease in refrigeration capacity. The relationship between the corrected compressor frequency and the high-pressure temperature is: f4’ = k4 * f4, where 0 < k4 < 1; that is, the frequency reduction rate is reduced, and f4’ is used as the default frequency reduction rate until |Pd2 - Pd1| < d2.

[0130] Corresponding to the frequency control method of the air conditioner provided in the above embodiment, this embodiment provides an air conditioner, which includes a computer-readable storage medium storing a computer program and a processor. When the computer program is read and run by the processor, the frequency control method of the air conditioner provided in the above embodiment is implemented.

[0131] This embodiment also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by the processor, each process of the frequency control method embodiment of the above air conditioner is implemented, and the same technical effects can be achieved. To avoid repetition, it will not be elaborated here. Among them, the computer-readable storage medium, such as a Read-Only Memory (ROM for short), a Random Access Memory (RAM for short), a magnetic disk or an optical disc, etc.

[0132] Of course, those skilled in the art can understand that all or part of the processes in the method of the above embodiment can be completed by a computer program instructing a control device. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of each method embodiment as described above. Among them, the storage medium can be a memory, a magnetic disk, an optical disc, etc.

[0133] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

[0134] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0135] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the air conditioner disclosed in the embodiments, since it corresponds to the frequency control method of the air conditioner disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0136] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0137] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A frequency control method for an air conditioner, characterized in that, include: During the operation of the air conditioner in frequency-up mode, obtain the current frequency and current low-pressure temperature; The low-pressure temperature corresponding to the current frequency when the air conditioner is running in a first preset stable state is determined to be the first low-pressure temperature; wherein, when the difference between the maximum low-pressure temperature and the minimum low-pressure temperature within a first preset time period is less than the first preset temperature difference, the air conditioner is determined to be in the first preset stable state. The low-pressure temperature corresponding to the current frequency of the air conditioner under preset rated conditions is determined and denoted as the rated low-pressure temperature; Based on the first low-pressure temperature, the rated low-pressure temperature, and the current low-pressure temperature, determine whether the frequency increase rate of the air conditioner is reasonable. If not, correct the compressor frequency so that the frequency increase rate of the air conditioner is within a reasonable range. The step of determining whether the frequency increase rate of the air conditioner is reasonable based on the first low-pressure temperature, the rated low-pressure temperature, and the current low-pressure temperature, and correcting the compressor frequency if not, so that the frequency increase rate of the air conditioner is within a reasonable range, includes: when the absolute value of the difference between the first low-pressure temperature and the rated low-pressure temperature is greater than the first temperature, and the current low-pressure temperature is greater than the first low-pressure temperature, controlling the compressor frequency to k1*f3; where 1 < k1, f3 is the functional relationship between the rated compressor frequency of the air conditioner and the current low-pressure temperature, f3 = a3*Ps 2 +b3*Ps+c3, where a3, b3, and c3 are all constants, and Ps is the current low-pressure temperature; when the absolute value of the difference between the first low-pressure temperature and the rated low-pressure temperature is greater than the first temperature, and the current low-pressure temperature is less than the first low-pressure temperature, the compressor frequency is controlled to be k2*f3; where 0 < k2 < 1.

2. The frequency control method as described in claim 1, characterized in that, The step of determining the low-pressure temperature corresponding to the current frequency when the air conditioner is operating in a preset stable state, and denoting it as the first low-pressure temperature, includes: Obtain the low-pressure temperature corresponding to each compressor frequency when the air conditioner is running in the first preset stable state; By performing function fitting on each compressor frequency and the low-pressure temperature corresponding to the compressor frequency, a functional relationship between the compressor frequency and the low-pressure temperature is obtained when the air conditioner is running in the first preset stable state, which is denoted as the first relationship. The first low-pressure temperature corresponding to the current frequency is determined based on the first relationship.

3. The frequency control method as described in claim 1, characterized in that, The step of determining the low-pressure temperature corresponding to the current frequency of the air conditioner under preset rated conditions, and denoting it as the rated low-pressure temperature, includes: Obtain the functional relationship between the rated compressor frequency of the air conditioner and the low-pressure temperature, and denote it as the first rated relationship; The rated low-pressure temperature corresponding to the current frequency is determined based on the first rated relationship.

4. The frequency control method as described in claim 1, characterized in that, Also includes: When the absolute value of the difference between the first low-pressure temperature and the rated low-pressure temperature is less than the first temperature, and the absolute value of the difference between the current low-pressure temperature and the first low-pressure temperature is less than the first temperature, the compressor frequency is controlled to be f3.

5. The frequency control method according to any one of claims 1-4, characterized in that, Also includes: While the air conditioner is operating in frequency reduction mode, obtain the current frequency and current high-pressure temperature; The high-pressure temperature corresponding to the current frequency when the air conditioner is running in a second preset stable state is determined and recorded as the first high-pressure temperature. Determine the high-pressure temperature corresponding to the current frequency of the air conditioner under preset rated conditions, and record it as the rated high-pressure temperature; Based on the first high-pressure temperature, the rated high-pressure temperature, and the current high-pressure temperature, determine whether the frequency reduction rate of the air conditioner is reasonable. If not, correct the compressor frequency so that the frequency reduction rate of the air conditioner is within a reasonable range. The step of determining whether the frequency reduction rate of the air conditioner is reasonable based on the first high-pressure temperature, the rated high-pressure temperature, and the current high-pressure temperature, and if not, correcting the compressor frequency to bring the frequency reduction rate of the air conditioner within a reasonable range, includes: When the absolute value of the difference between the first high-pressure temperature and the rated high-pressure temperature is greater than the second temperature, and the current high-pressure temperature is greater than the first high-pressure temperature, the compressor frequency is controlled to be k3*f4; where 1 < k3, f4 is the functional relationship between the rated compressor frequency of the air conditioner and the current high-pressure temperature, f4 = a4*Pd 2 +b4*Pd+c4, where a4, b4, and c4 are all constants, and Pd is the current high-pressure temperature; When the absolute value of the difference between the first high-pressure temperature and the rated high-pressure temperature is greater than the second temperature, and the current high-pressure temperature is less than the first high-pressure temperature, the compressor frequency is controlled to be k4*f4; where 0 < k4 < 1. When the absolute value of the difference between the first high-pressure temperature and the rated high-pressure temperature is less than the second temperature, and the absolute value of the difference between the current high-pressure temperature and the first high-pressure temperature is less than the second temperature, the compressor frequency is controlled to be f4.

6. The frequency control method as described in claim 5, characterized in that, The step of determining the high-pressure temperature corresponding to the current frequency when the air conditioner is operating in a second preset stable state, and denoting it as the first high-pressure temperature, includes: The high-pressure temperature corresponding to each compressor frequency of the air conditioner is obtained when the air conditioner is running in the second preset stable state; wherein, when the difference between the maximum high-pressure temperature and the minimum high-pressure temperature within the second preset time period is less than the second preset temperature difference, the air conditioner is determined to be in the second preset stable state. By performing function fitting on each compressor frequency and the high-pressure temperature corresponding to the compressor frequency, a functional relationship between the compressor frequency and the high-pressure temperature is obtained when the air conditioner is running in the second preset stable state, which is denoted as the second relationship. The first high-pressure temperature corresponding to the current frequency is determined based on the second relationship.

7. The frequency control method as described in claim 5, characterized in that, The step of determining the high-pressure temperature corresponding to the current frequency of the air conditioner under preset rated conditions, and denoting it as the rated high-pressure temperature, includes: Obtain the functional relationship between the rated compressor frequency of the air conditioner and the high-pressure temperature, and denote it as the second rated relationship; The rated high-voltage temperature corresponding to the current frequency is determined based on the second rated relationship.

8. An air conditioner, characterized in that, The method includes a computer-readable storage medium storing a computer program, which is read and executed by the processor to implement the method as described in any one of claims 1-7.

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