A control method of an air conditioner

Abstract

The application discloses a control method of an air conditioner, and the control method comprises the following steps: receiving a starting heating instruction, and entering a heating mode; acquiring an indoor air temperature, an outdoor air temperature and a set temperature, and determining a heat exchange pipe temperature target value of a first heat exchanger according to the indoor air temperature, the outdoor air temperature and the set temperature; detecting a current heat exchange pipe temperature of the first heat exchanger, and increasing a frequency of a compressor and / or reducing a rotating speed of a fan when the current heat exchange pipe temperature is less than the heat exchange pipe temperature target value. The application aims at solving the technical problem that the existing air conditioner outputs cold air in the heating mode, thereby causing the user to feel cold.

Description

Technical Field

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

[0002] Current air conditioners often output excessively hot or cold air in heating mode, resulting in poor comfort and a poor user experience. For example:

[0003] (1) When the indoor temperature is already high, the air temperature output by the indoor unit of the air conditioner is still very high, and users are prone to feeling hot and dry.

[0004] (2) When the air conditioner is first turned on for heating, the amount of heat delivered from the outdoor unit to the indoor unit is small, resulting in the indoor unit outputting cold air.

[0005] (3) When the air conditioner is heating in extremely low outdoor temperatures, the temperature of the air output by the indoor unit is usually low and does not reach a comfortable temperature.

[0006] (4) When heating is turned on, when the hot air from the heating system blows back onto the temperature sensor used to detect the indoor temperature, the system will assume that the indoor temperature has reached the set temperature and reduce the heating power, resulting in a decrease in the supply air temperature and making the body feel colder. Summary of the Invention

[0007] The main objective of this invention is to provide a control method for an air conditioner, which aims to solve the technical problem that existing air conditioners output cold air in heating mode, causing users to feel too cold.

[0008] A control method for an air conditioner, the air conditioner comprising a first heat exchanger for exchanging heat with indoor air, a fan for driving airflow through the first heat exchanger, a second heat exchanger for exchanging heat with outdoor air, and a compressor for driving refrigerant to circulate between the first heat exchanger and the second heat exchanger.

[0009] The control method includes:

[0010] Receives the command to start heating and enters heating mode;

[0011] The system acquires the indoor air temperature, outdoor air temperature, and set temperature, and determines the target value of the heat exchange tube temperature of the first heat exchanger based on these values.

[0012] The current heat exchange tube temperature of the first heat exchanger is detected. If the current heat exchange tube temperature is less than the target value of the heat exchange tube temperature, the compressor frequency is increased and / or the fan speed is reduced.

[0013] In one illustrative embodiment, the target temperature value of the heat exchange tube ranges from 39.5 to 54°C.

[0014] In one illustrative embodiment, the target temperature value of the heat exchanger tubes of the first heat exchanger is calculated according to the following formula:

[0015] T2s=a×T1+b×Ts+c×T4+d

[0016] Wherein, T2s is the target temperature value of the heat exchange tube of the first heat exchanger;

[0017] T1 represents the indoor temperature;

[0018] 'a' is the weighting coefficient for indoor temperature, and its value ranges from -0.3 to 0.1.

[0019] Ts is the set temperature;

[0020] b is the weighting coefficient for the set temperature, and its value ranges from 0.1 to 0.3;

[0021] T4 represents the outdoor temperature;

[0022] c is the weighting coefficient for outdoor temperature, and its value ranges from -0.1 to 0.1;

[0023] d is a correction factor, and its value ranges from 40 to 54.

[0024] In one illustrative embodiment, the fan speed is reduced when the current heat exchange tube temperature is lower than the target value of the heat exchange tube temperature and the operating frequency of the compressor is already limited;

[0025] When the current heat exchange tube temperature is less than the target value of the heat exchange tube temperature and the compressor operating frequency is not restricted, the compressor operating frequency is increased.

[0026] In one illustrative embodiment, the condition for limiting the compressor's operating frequency is that the compressor's outlet temperature is less than a temperature threshold and the compressor's current is less than a current threshold.

[0027] In one illustrative embodiment, the temperature threshold ranges from 90 to 100°C, and the current threshold ranges from 12 to 18A.

[0028] In one illustrative embodiment, a step is also included after detecting the current heat exchanger tube temperature:

[0029] When the current heat exchange tube temperature is equal to the target value of the heat exchange tube temperature, the fan speed and the compressor operating frequency remain unchanged.

[0030] In one illustrative embodiment, a step is also included after detecting the current heat exchanger tube temperature:

[0031] When the current heat exchange tube temperature is equal to the target value of the heat exchange tube temperature, if defrosting is required, the system will enter defrosting mode to perform defrosting.

[0032] In one illustrative embodiment, the system re-enters heating mode after defrosting is complete.

[0033] In one illustrative embodiment, a step is also included after detecting the current heat exchanger tube temperature:

[0034] Increase the fan speed when the current heat exchange tube temperature is greater than the target value of the heat exchange tube temperature.

[0035] In this invention, the target temperature of the heat exchanger tube of the first heat exchanger is determined based on the indoor air temperature, outdoor air temperature, and a set temperature. When the current heat exchanger tube temperature is lower than its target temperature, the temperature of the airflow output from the air conditioner's outlet is low. This can be addressed by increasing the compressor frequency, thereby accelerating the heat exchange rate between the second heat exchanger and the outdoor air, as well as the heat transfer rate between the second and first heat exchangers. This increases the temperature of the heat exchanger tube of the first heat exchanger, bringing it closer to the target temperature. Furthermore, as the heat exchanger tube temperature increases, the temperature of the airflow output from the air conditioner's outlet also rises accordingly.

[0036] When the current heat exchanger tube temperature of the first heat exchanger is lower than its target temperature, the airflow temperature output from the air conditioner's outlet is low. The flow rate of the airflow exchanging heat with the first heat exchanger can be reduced by decreasing the fan speed, thus increasing the temperature of the heat exchanger tubes and bringing the temperature closer to the target value. Consequently, the temperature of the airflow output from the air conditioner's outlet also increases due to the increased heat exchanger tube temperature. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0038] Figure 1 This is a flowchart of a control method for an air conditioner according to an embodiment of this application;

[0039] Figure 2 This is a flowchart of a control method for an air conditioner according to an embodiment of this application.

[0040] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0041] 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 a part of the embodiments of the present invention, and not all of the 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.

[0042] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0043] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0044] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0046] This invention proposes a control method for an air conditioner. The air conditioner includes an indoor unit, an outdoor unit, and a control device.

[0047] Indoor units are typically installed inside a building. An indoor unit includes a casing, a first temperature sensor, a second temperature sensor, a fan, and a first heat exchanger. The casing has an air inlet and an air outlet, and an airflow duct is located inside the casing. The two ends of the airflow duct are connected to the air inlet and the air outlet, respectively. The fan and the first heat exchanger are both located within the air inlet duct. When the fan is running, it draws indoor air into the airflow duct through the air inlet and then exits the indoor unit through the air outlet. The airflow exchanges heat with the first heat exchanger as it flows through it. In heating mode, the first heat exchanger transfers heat to the airflow so that hot air can be output from the air outlet. In cooling mode, the first heat exchanger transfers cold air to the airflow so that cold air can be output from the air outlet. The first temperature sensor measures the indoor air temperature. The second temperature sensor measures the temperature of the heat exchange tubes of the first heat exchanger.

[0048] The outdoor unit is typically installed on the outside of a building. It includes an inverter, a second heat exchanger, and a third temperature sensor. The second heat exchanger exchanges heat with the outdoor air. The inverter, the first heat exchanger, and the second heat exchanger are connected in a loop via refrigerant piping. The inverter drives the refrigerant to circulate between the first and second heat exchangers. In heating mode, the outdoor air exchanges heat with the refrigerant in the second heat exchanger, transferring heat to the refrigerant. The refrigerant then carries the heat to the first heat exchanger and transfers it to the airflow passing through it. The third temperature sensor detects the outdoor air temperature.

[0049] The control device is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor, the fan, and the frequency converter.

[0050] like Figure 1 As shown, this embodiment also proposes a control method for an air conditioner. This control method is implemented based on the aforementioned air conditioner and includes:

[0051] Step S1: Receive the heating start command and proceed to step S2;

[0052] The command to start heating can be sent by the user to the air conditioner via the air conditioner's remote control or a mobile device, such as a mobile phone, tablet, or smart speaker.

[0053] The "Start Heating" command is used to instruct the air conditioner to enter heating mode for heating.

[0054] Step S2: The air conditioner enters heating mode, proceed to step S3;

[0055] After receiving the command to start heating, the air conditioner enters heating mode. Once in heating mode, the control unit starts the compressor to provide heating.

[0056] Step S3: Obtain the indoor temperature, outdoor temperature, and set temperature, and determine the target temperature value of the heat exchange tube of the first heat exchanger based on the indoor temperature, outdoor temperature, and set temperature, then proceed to step S4;

[0057] The control device measures the indoor temperature using a first temperature sensor. The control device measures the outdoor temperature using a third temperature sensor.

[0058] The set temperature is the temperature that the user expects the air conditioner to reach when heating. The set temperature is a preset temperature, which can be set by the user or it can be a default temperature, such as the temperature set in the last heating mode.

[0059] The target temperature of the heat exchange tube of the first heat exchanger is the expected value of the heat exchange tube temperature of the first heat exchanger. The air conditioner can adjust the heat exchange tube temperature of the first heat exchanger to the target value by controlling the fan and compressor.

[0060] The control device determines the target temperature value of the heat exchange tube of the first heat exchanger based on the indoor temperature, outdoor temperature, and set temperature.

[0061] Step S4: Detect the current heat exchange tube temperature of the first heat exchanger;

[0062] If the current heat exchange tube temperature of the first heat exchanger is less than the target value of the heat exchange tube temperature of the first heat exchanger, then increase the frequency of the compressor and / or reduce the speed of the fan.

[0063] If the current heat exchange tube temperature of the first heat exchanger is equal to the target value of the heat exchange tube temperature of the first heat exchanger, then keep the fan speed and the compressor frequency unchanged.

[0064] If the current heat exchange tube temperature of the first heat exchanger is greater than the target value of the heat exchange tube temperature of the first heat exchanger, then increase the fan speed.

[0065] The control device measures the current heat exchange tube temperature of the first heat exchanger using a second temperature sensor.

[0066] When the current heat exchanger tube temperature of the first heat exchanger is lower than its target temperature, the air temperature output from the air conditioner's outlet is low. This can be addressed by increasing the compressor frequency, which accelerates the heat exchange between the second heat exchanger and the outdoor air, as well as the heat transfer between the second and first heat exchangers. This increases the temperature of the first heat exchanger tube, bringing it closer to its target temperature. Consequently, the increased temperature of the first heat exchanger tube leads to a corresponding increase in the temperature of the air output from the air conditioner's outlet.

[0067] When the current heat exchanger tube temperature of the first heat exchanger is lower than its target temperature, the airflow temperature output from the air conditioner's outlet is low. The flow rate of the airflow exchanging heat with the first heat exchanger can be reduced by decreasing the fan speed, thus increasing the temperature of the heat exchanger tubes and bringing the temperature closer to the target value. Consequently, the temperature of the airflow output from the air conditioner's outlet also increases due to the increased heat exchanger tube temperature.

[0068] Of course, when the current heat exchange tube temperature of the first heat exchanger is lower than its target heat exchange tube temperature, the temperature of the airflow output from the air outlet of the air conditioner is low. The compressor frequency can be increased while the fan speed is reduced to quickly raise the heat exchange tube temperature of the first heat exchanger, thereby increasing the temperature of the airflow output from the air outlet of the air conditioner accordingly.

[0069] When the current heat exchange tube temperature of the first heat exchanger is equal to its target heat exchange tube temperature, the temperature of the airflow output from the air conditioner's outlet is appropriate. Therefore, it is not necessary to change the heat exchange tube temperature of the first heat exchanger, and the compressor frequency and fan speed remain unchanged.

[0070] When the current heat exchange tube temperature of the first heat exchanger is greater than its target heat exchange tube temperature, the temperature of the airflow output from the air conditioner's outlet is higher. Increasing the fan speed can increase the speed of the airflow passing through the first heat exchanger, thereby lowering the airflow temperature and consequently lowering the temperature of the airflow output from the air conditioner's outlet.

[0071] In some embodiments, the target temperature value of the heat exchange tube of the first heat exchanger ranges from 39.5 to 54°C.

[0072] When the temperature of the heat exchange tubes in the first heat exchanger is between 39.5 and 54°C, the temperature of the air supplied from the outlet is relatively comfortable.

[0073] In some embodiments, in step S3, the target temperature value of the heat exchange tube of the first heat exchanger can be calculated according to the following formula:

[0074] T2s=a×T1+b×Ts+c×T4+d

[0075] Wherein, T2s is the target temperature value of the heat exchange tube of the first heat exchanger, in °C;

[0076] T1 is the indoor temperature, in °C;

[0077] 'a' is the weighting coefficient for indoor temperature, and its value ranges from -0.3 to 0.1.

[0078] Ts is the set temperature, in °C;

[0079] b is the weighting coefficient for the set temperature, and its value ranges from 0.1 to 0.3;

[0080] T4 represents the outdoor temperature, in °C.

[0081] c is the weighting coefficient for outdoor temperature, and its value ranges from -0.1 to 0.1;

[0082] d is a correction factor, and its value ranges from 40 to 54;

[0083] Among them, a, b, c, and d can be calibrated according to actual working conditions to ensure that the target temperature value T2s of the heat exchange tube is within a reasonable range, thereby making the air outlet temperature of the air conditioner comfortable.

[0084] In some embodiments, when the indoor temperature T1 is greater than 25°C and the outdoor temperature T4 is greater than 11°C, a = -0.1, b = 0.1, c = -0.05, d = 40, and T2s = 0.1Ts - 0.1T1 - 0.05T4 + 40.

[0085] When the indoor temperature T1 is less than or equal to 25℃ and greater than 20℃, and the outdoor temperature T4 is greater than 11℃, a = -0.1, b = 0.1, c = -0.1, d = 45, and T2s = 0.1Ts - 0.1T1 - 0.1T4 + 45.

[0086] When the indoor temperature T1 is less than or equal to 20℃ and greater than 10℃, and the outdoor temperature T4 is greater than 11℃, a = -0.1, b = 0.1, c = -0.1, d = 50, and T2s = 0.1Ts - 0.1T1 - 0.1T4 + 50.

[0087] When the indoor temperature T1 is less than 10℃ and the outdoor temperature T4 is greater than 11℃, a = 0, b = 0, c = 0, d = 54, and T2s = 54.

[0088] When the indoor temperature T1 is greater than 25℃ and the outdoor temperature T4 is less than or equal to 11℃ and greater than 6℃, a = -0.1, b = 0.1, c = -0.1, d = 45, and T2s = 0.1Ts - 0.1T1 - 0.1T4 + 45.

[0089] When the indoor temperature T1 is less than or equal to 25℃ and greater than 20℃, and the outdoor temperature T4 is less than or equal to 11℃ and greater than 6℃, a = -0.2, b = 0.2, c = -0.1, d = 45, and T2s = 0.2Ts - 0.2T1 - 0.1T4 + 45.

[0090] When the indoor temperature T1 is less than or equal to 20℃ and the outdoor temperature T4 is less than or equal to 11℃ and greater than 6℃, a = 0, b = 0, c = 0, d = 54, and T2s = 54.

[0091] When the indoor temperature T1 is greater than 25℃ and the outdoor temperature T4 is greater than 0℃ and less than or equal to 6℃, a = -0.2, b = 0.2, c = -0.1, d = 45, and T2s = 0.2Ts - 0.2T1 - 0.1T4 + 45.

[0092] When the indoor temperature T1 is less than or equal to 25℃ and greater than 20℃, and the outdoor temperature T4 is greater than 0℃ and less than or equal to 6℃, a = -0.3, b = 0.3, c = -0.05, d = 45, and T2s = 0.3Ts - 0.3T1 - 0.05T4 + 45.

[0093] When the indoor temperature T1 is less than or equal to 20℃ and the outdoor temperature T4 is greater than 0℃ and less than or equal to 6℃, a = 0, b = 0, c = 0, d = 54, and T2s = 54.

[0094] When the indoor temperature T1 is greater than 25℃ and the outdoor temperature T4 is less than or equal to 0℃ and greater than -6℃, a = -0.2, b = 0.25, c = -0.1, d = 45, and T2s = 0.25Ts - 0.2T1 - 0.1T4 + 45.

[0095] When the indoor temperature T1 is less than or equal to 25℃ and greater than 20℃, and the outdoor temperature T4 is less than or equal to 0℃ and greater than -6℃, a = -0.2, b = 0.25, c = -0.1, d = 45, and T2s = 0.25Ts - 0.2T1 - 0.1T4 + 45.

[0096] When the indoor temperature T1 is less than or equal to 20℃ and greater than 10℃, and the outdoor temperature T4 is less than or equal to 0℃ and greater than -6℃, a = 0, b = 0, c = 0, d = 54, and T2s = 54.

[0097] When the indoor temperature T1 is less than or equal to 10℃ and the outdoor temperature T4 is less than or equal to 0℃ and greater than -6℃, a = 0.1, b = 0.1, c = 0.05, d = 46, and T2s = 0.1Ts + 0.1T1 + 0.05T4 + 46.

[0098] When the indoor temperature T1 is greater than 25℃ and the outdoor temperature T4 is less than or equal to -6℃ and greater than -15℃, a = -0.2, b = 0.3, c = -0.05, d = 45, and T2s = 0.3Ts - 0.2T1 - 0.05T4 + 45.

[0099] When the indoor temperature T1 is less than or equal to 25℃ and greater than 20℃, and the outdoor temperature T4 is less than or equal to -6℃ and greater than -15℃, a = -0.2, b = 0.3, c = -0.1, d = 47, and T2s = 0.3Ts - 0.2T1 - 0.1T4 + 47.

[0100] When the indoor temperature T1 is less than or equal to 20℃ and greater than 10℃, and the outdoor temperature T4 is less than or equal to -6℃ and greater than -15℃, a = 0.1, b = 0.1, c = 0.05, d = 44, and T2s = 0.1Ts + 0.1T1 + 0.05T4 + 44.

[0101] When the indoor temperature T1 is less than or equal to 10℃ and the outdoor temperature T4 is less than or equal to -6℃ and greater than -15℃, a = 0.1, b = 0.1, c = 0.05, d = 43, and T2s = 0.1Ts + 0.1T1 + 0.05T4 + 43.

[0102] When the indoor temperature T1 is greater than 25℃ and the outdoor temperature T4 is less than or equal to -15℃, a = -0.1, b = 0.1, c = 0.025, d = 51, and T2s = 0.1Ts - 0.1T1 + 0.025T4 + 51.

[0103] When the indoor temperature T1 is less than or equal to 25℃ and greater than 20℃, and the outdoor temperature T4 is less than or equal to -15℃, a = 0.1, b = 0.1, c = 0.05, d = 42, and T2s = 0.1Ts + 0.1T1 + 0.05T4 + 43.

[0104] When the indoor temperature T1 is less than or equal to 20℃ and greater than 10℃, and the outdoor temperature T4 is less than or equal to -15℃, a = 0.1, b = 0.1, c = 0.05, d = 41, and T2s = 0.1Ts + 0.1T1 + 0.05T4 + 41.

[0105] When the indoor temperature T1 is less than or equal to 10℃ and the outdoor temperature T4 is less than or equal to -15℃, a = 0.1, b = 0.1, c = 0.05, d = 40, and T2s = 0.1Ts + 0.1T1 + 0.05T4 + 40.

[0106] When the air conditioner is in heating mode, using the above parameter configuration ensures that the target temperature of the heat exchanger tube is always maintained within the optimal range. Reaching this target temperature on the heat exchanger tubes of the first heat exchanger allows the air conditioner to output air at a comfortable temperature, improving the user experience. Simultaneously, when the indoor temperature is low, the target temperature of the heat exchanger tube will be raised to its maximum. This prevents short-circuiting of the return air caused by hot air recirculation and allows the air conditioner to output hot air at the highest possible power.

[0107] In one illustrative embodiment, such as Figure 2 As shown, step S2 includes steps S21 to S23.

[0108] Step S21: Drive the compressor to run for heating, proceed to step S22;

[0109] The control device drives the compressor to run after receiving the start heating command.

[0110] Step S22: Obtain the current operating frequency of the compressor, proceed to step S23;

[0111] After the control device drives the compressor to start, the compressor's operating frequency gradually increases. The control device can obtain the compressor's current operating frequency.

[0112] Step S23: Determine whether the current operating frequency has reached the target frequency. If yes, proceed to step S3; otherwise, proceed to step S22.

[0113] The target frequency of the compressor is the frequency that the compressor is to achieve, and the initial target frequency can be a preset value.

[0114] The control device compares the current operating frequency with the target frequency each time it acquires the information. After the current operating frequency reaches the target frequency, the compressor is maintained at the target frequency and then the process proceeds to step S3.

[0115] In one illustrative embodiment, step S4 includes steps S41 to S45.

[0116] Step S41: Detect the current heat exchange tube temperature of the first heat exchanger;

[0117] The control device uses a second temperature sensor to detect the current temperature of the heat exchange tubes of the first heat exchanger.

[0118] Step S42: Determine whether the current heat exchange tube temperature of the first heat exchanger is less than the target value of the heat exchange tube temperature of the first heat exchanger. If so, proceed to step S43.

[0119] Step S43: Determine whether the compressor's operating frequency is already limited. If so, proceed to step S44; otherwise, proceed to step S45.

[0120] Compressor operating frequency limiting refers to setting a threshold for the compressor's operating frequency to prevent it from exceeding that threshold. Under extreme operating conditions, the compressor's operating frequency is limited to below a certain threshold to prevent damage.

[0121] Step S44: Reduce the fan speed and proceed to step S3;

[0122] When the compressor's operating frequency is limited, the air conditioner cannot increase the temperature of the air coming out of the vent by increasing the compressor's operating frequency. In this case, the temperature of the air coming out of the vent is increased by reducing the fan speed.

[0123] Step S45: Increase the target frequency of the compressor and proceed to step S22.

[0124] In this step, after increasing the target frequency of the compressor, the operating frequency of the compressor can be increased to the target frequency in steps S22 and S23, thus realizing the increase of the operating frequency of the compressor by increasing the target frequency of the compressor.

[0125] When the compressor frequency is not limited, the air conditioner can increase the temperature of the air outlet by increasing the compressor frequency. In this case, the air outlet temperature is increased by increasing the compressor frequency first, so as to increase the air outlet temperature without reducing the air volume at the outlet.

[0126] In one illustrative embodiment, step S43 includes steps S431 to S432.

[0127] Step S431: Determine whether the compressor outlet temperature is lower than the temperature threshold. If yes, proceed to step S432; otherwise, proceed to step S45.

[0128] Step S432: Determine whether the compressor current is less than the current threshold. If yes, proceed to step S44; otherwise, proceed to step S45.

[0129] In this embodiment, when the compressor outlet temperature is less than the temperature threshold and the compressor current is less than the current threshold, the compressor operating frequency is limited, and the fan speed is reduced.

[0130] Both the temperature threshold and the current threshold are preset values ​​and can be selected according to the actual operating conditions of the compressor. In this embodiment, the temperature threshold ranges from 90 to 100°C, and the current threshold ranges from 12 to 18A.

[0131] When the compressor's outlet temperature is greater than or equal to the temperature threshold or when the compressor's current is greater than or equal to the current threshold, the compressor's operating frequency is not limited. In this case, the compressor's operating frequency is increased by using the compressor's target frequency.

[0132] In one illustrative embodiment, step S4 further includes steps S46 to S49.

[0133] In step S42, if the current heat exchange tube temperature of the first heat exchanger is not less than the target value of the heat exchange tube temperature of the first heat exchanger, then proceed to step S46.

[0134] Step S46: Determine if the current heat exchange tube temperature of the first heat exchanger is equal to the target value of the heat exchange tube temperature of the first heat exchanger. If so, proceed to step S47.

[0135] Step S47: Maintain the fan speed and the compressor target frequency unchanged;

[0136] When the current heat exchange tube temperature of the first heat exchanger is equal to the target value of the heat exchange tube temperature of the first heat exchanger, the outlet air temperature is moderate, and there is no need to adjust the fan speed and the compressor operating frequency.

[0137] Step S48: Determine whether defrosting is needed. If yes, proceed to step S49; otherwise, proceed to step S21.

[0138] When an air conditioner is in heating mode during winter, the temperature of the heat exchange tubes in the second heat exchanger may drop below zero. Frost may form on the surface of the second heat exchanger, and a thick layer of frost can obstruct airflow, affecting the heating capacity of the air conditioner.

[0139] After the air conditioner detects frost on the surface of the second heat exchanger, it needs to enter defrost mode to remove the frost from the surface of the second heat exchanger.

[0140] Whether the second heat exchanger of an air conditioner is frosted can be determined by detecting the temperature of the heat exchange tubes. When the temperature of the heat exchange tubes is lower than a first preset threshold, the second heat exchanger is considered to be frosted. This first preset threshold can be measured in advance in an experimental environment.

[0141] The air conditioner can also detect whether frost has formed on the second heat exchanger by detecting the temperature of the heat exchanger tubes of the first heat exchanger and the indoor air temperature after the compressor has accumulated more than a preset running time. This allows the system to determine whether the temperature difference between the heat exchanger tubes of the first heat exchanger and the indoor air temperature is less than a second preset threshold. This first preset threshold can be measured in advance under experimental conditions.

[0142] When the air conditioner needs to defrost, a defrost indicator is set in the control device. When entering this step, the control device reads the defrost indicator and controls the air conditioner to enter the defrost mode to defrost.

[0143] Step S49: Enter defrost mode to defrost, and after defrosting is complete, proceed to step S21;

[0144] When the air conditioner is defrosting, the indoor unit's fan stops rotating, the air conditioner heats the outdoor unit, and the second heat exchanger releases heat to melt the frost that has condensed on the second heat exchanger.

[0145] After the air conditioner finishes defrosting, it will re-enter heating mode to heat.

[0146] In one illustrative embodiment, step S4 further includes step S50.

[0147] If the current heat exchange tube temperature of the first heat exchanger is not equal to the target value of the heat exchange tube temperature of the first heat exchanger in step S46, then proceed to step S50.

[0148] Since the current heat exchange tube temperature of the first heat exchanger is neither less than nor equal to the target temperature value of the first heat exchanger, the current heat exchange tube temperature of the first heat exchanger can only be greater than the target temperature value of the first heat exchanger.

[0149] Because the current heat exchange tube temperature of the first heat exchanger is higher than the target value of the heat exchange tube temperature, the temperature of the air outlet is relatively high.

[0150] Step S50: Increase the fan speed and proceed to step S3.

[0151] The control device increases the fan speed to speed up the time it takes for the airflow to pass through the first heat exchanger, thereby reducing the outlet air temperature, increasing the outlet air volume, and also cooling the first heat exchanger.

[0152] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A control method for an air conditioner, characterized in that, The air conditioner includes a first heat exchanger for exchanging heat with indoor air, a fan for driving airflow through the first heat exchanger, a second heat exchanger for exchanging heat with outdoor air, and a compressor for driving refrigerant to circulate between the first heat exchanger and the second heat exchanger. The control method includes: Receives the command to start heating and enters heating mode; The system acquires the indoor air temperature, outdoor air temperature, and set temperature, and determines the target value of the heat exchange tube temperature of the first heat exchanger based on these values. The current heat exchange tube temperature of the first heat exchanger is detected. If the current heat exchange tube temperature is lower than the target value of the heat exchange tube temperature, the compressor frequency is increased or the fan speed is reduced. The step of determining the target temperature value of the heat exchange tube of the first heat exchanger based on the indoor temperature, outdoor temperature and set temperature includes: determining the target temperature value of the heat exchange tube of the first heat exchanger based on the indoor temperature, the weighting coefficient of the indoor temperature, the set temperature, the weighting coefficient of the set temperature, the outdoor temperature, the weighting coefficient of the outdoor temperature and a correction coefficient. The target temperature value of the heat exchanger tubes of the first heat exchanger is calculated using the following formula: T2s = a × T1 + b × Ts + c × T4 + d Wherein, T2s is the target temperature value of the heat exchange tube of the first heat exchanger; T1 represents the indoor temperature; 'a' is the weighting coefficient for indoor temperature, and its value ranges from -0.3 to 0.

1. Ts is the set temperature; b is the weighting coefficient for the set temperature, and its value ranges from 0.1 to 0.3; T4 represents the outdoor temperature; c is the weighting coefficient for outdoor temperature, and its value ranges from -0.1 to 0.1; d is a correction factor, and its value ranges from 40 to 54; The step of increasing the compressor frequency or decreasing the fan speed when the current heat exchange tube temperature is lower than the target value of the heat exchange tube temperature includes: When the current heat exchange tube temperature is lower than the target value of the heat exchange tube temperature and the compressor operating frequency is already limited, reduce the fan speed; When the current heat exchange tube temperature is less than the target value of the heat exchange tube temperature and the compressor operating frequency is not restricted, increase the compressor operating frequency. The conditions for determining that the compressor's operating frequency is limited are that the compressor's outlet temperature is less than the temperature threshold and the compressor's current is less than the current threshold.

2. The control method according to claim 1, characterized in that, The target temperature value of the heat exchange tube is in the range of 39.5~54℃.

3. The control method according to claim 1, characterized in that, The temperature threshold ranges from 90 to 100°C, and the current threshold ranges from 12 to 18A.

4. The control method according to any one of claims 1 to 2, characterized in that, Also includes: When the current heat exchange tube temperature is equal to the target value of the heat exchange tube temperature, the fan speed and the compressor operating frequency remain unchanged.

5. The control method according to claim 4, characterized in that, Also includes: When the current heat exchange tube temperature is equal to the target value of the heat exchange tube temperature, if the second heat exchanger needs to defrost, it will enter the defrosting mode to defrost.

6. The control method according to claim 5, characterized in that, After defrosting is complete, it will re-enter heating mode.

7. The control method according to any one of claims 1 to 2, characterized in that, Also includes: Increase the fan speed when the current heat exchange tube temperature is greater than the target value of the heat exchange tube temperature.

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