Air conditioning system and control method for starting an external fan against the wind

Abstract

The application discloses an air conditioner system and a control method for starting an external fan against wind, and belongs to the technical field of air conditioner systems. The air conditioner system comprises an external fan and a condenser, and further comprises a wind blocking structure arranged between the external fan and the condenser. The wind blocking structure has at least two assembly states, i.e. parallel to the plane where the external fan is located and perpendicular to the plane where the external fan is located. Compared with the prior art, the wind blocking structure is added behind the external fan, and the wind blocking structure is perpendicular to the plane where the external fan is located when the air conditioner system is powered off. Therefore, the reverse rotating speed of the external fan can be reduced when the air conditioner system is powered off, and the loss caused by the reverse rotation of the external fan can be reduced.

Description

Technical Field

[0001] This invention relates to the field of refrigeration, and in particular to an air conditioning system and a control method for starting an outdoor fan against the wind. Background Technology

[0002] Air conditioning systems are common refrigeration equipment widely used in daily life and various fields. The outdoor fans of air conditioning systems often operate in harsh environments, such as high temperatures, low temperatures, strong winds, and humidity. Therefore, overcoming harsh environments and maintaining the normal operation and performance of air conditioning systems is crucial.

[0003] In windy environments, when the air conditioning system is powered off and not running, the outdoor fan of the air conditioning system is prone to reverse rotation, which will increase the losses caused by the outdoor fan reversing when the air conditioning system is started.

[0004] Therefore, how to design a control method for the reverse start of an air conditioning system and its outdoor fan to solve the problem of the outdoor fan reversing when the air conditioning system is in a power outage state is a technical problem that the industry urgently needs to solve. Summary of the Invention

[0005] In view of the problem that the outdoor fan of the air conditioning system is prone to reverse rotation when the power is off in the existing technology, the present invention proposes a control method for the air conditioning system and the outdoor fan to start in reverse.

[0006] The technical solution of the present invention is to propose an air conditioning system, including an outdoor fan and a condenser, and further including a windbreak structure disposed between the outdoor fan and the condenser;

[0007] The windbreak structure has at least two assembly states: parallel to the plane where the external fan is located, and perpendicular to the plane where the external fan is located.

[0008] Furthermore, the windbreak structure includes multiple louver blades and a motor for controlling the rotation of all the louver blades;

[0009] The motor can control the arrangement direction of the louvers to be parallel or perpendicular to the plane where the external fan is located, and when the air conditioning system is in a power-off state, the motor controls the arrangement direction of the louvers to be parallel to the plane where the external fan is located.

[0010] This invention also proposes a control method for the reverse-wind start-up of an outdoor fan in an air conditioning system, comprising:

[0011] Step S1: Detect the rotation direction of the external fan. When the rotation direction of the external fan is positive, proceed to step S2.

[0012] Step S2: Adjust the angle between the louver blades in the windbreak structure and the plane where the external fan is located, as well as the control duty cycle of the external fan, so that the speed of the external fan reaches the first preset speed range;

[0013] Step S3: Using the control duty cycle and the rotational speed of the external fan as inputs, perform closed-loop control on the external fan;

[0014] Step S4: Detect the speed of the outdoor fan. When the speed of the outdoor fan reaches the second preset speed range, turn on the compressor in the air conditioning system.

[0015] Furthermore, step S1 also includes:

[0016] Step S11: When the rotation direction of the external fan is reversed, increase the control duty cycle of the external fan;

[0017] Step S12: Detect whether the reverse rotation speed of the external fan has decreased. If yes, proceed to step S13; otherwise, return to step S11.

[0018] Step S13: Maintain the control duty cycle of the external fan. When the rotation direction of the external fan changes to forward or stops, proceed to step S2.

[0019] Furthermore, in step S11, the control duty cycle of the external fan satisfies the calculation model:

[0020]

[0021] Wherein, D1 is the control duty cycle of the external fan in step S1, D0 is the reference duty cycle, t1 is the control cycle, and n is the total judgment cycle;

[0022] The external fan increases its control duty cycle by increasing the total judgment period.

[0023] Furthermore, the adjustment model for the angle between the louver blades in the windbreak structure and the plane where the external fan is located in step S2 is as follows:

[0024]

[0025] Wherein, α is the angle between the louver blades in the windbreak structure and the plane where the external fan is located, k is the total number of stages of the external fan starting against the wind, and k1 is the current stage of the external fan starting against the wind.

[0026] Furthermore, the adjustment model for the control duty cycle of the external fan in step S2 is as follows:

[0027]

[0028] Wherein, D is the control duty cycle of the external fan in step S2, and D1 is the control duty cycle of the external fan in step S1. target k is the set duty cycle of the external fan in the current gear position, k is the total number of stages of the external fan starting against the wind, and k1 is the current stage of the external fan starting against the wind.

[0029] Furthermore, step S2 also includes:

[0030] Step S21: When the current stage number of the outdoor fan starting against the wind is equal to the total number of stages of the outdoor fan starting against the wind, detect the current speed of the outdoor fan;

[0031] Step S22: Determine whether the current speed of the external fan has reached the first preset speed range. If yes, proceed to step S3; otherwise, proceed to step S23.

[0032] Step S23: Continue to increase the control duty cycle of the external fan in step S2, and each increase in duty cycle is the reference duty cycle in step S1, and return to step S22.

[0033] Furthermore, the closed-loop control strategy in step S3 is a PID control strategy.

[0034] Furthermore, the first preset speed range is (0.8n) target ,∞), the second preset speed range is (0.95n target 1.05n target ), where n target The target rotational speed of the external fan.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] 1. The present invention adds a windbreak structure between the outdoor fan and the condenser. When the air conditioning system is in a power-off state, the windbreak structure can control the arrangement direction of the louvers in the windbreak structure to be parallel to the plane where the outdoor fan is located. In this arrangement, the windbreak structure can block the external air intake, thereby reducing the reverse rotation speed of the outdoor fan when the air conditioning system is in a power-off state.

[0037] 2. This invention proposes a control method for starting an external fan against the wind, which can gradually adjust the operating resistance of the external fan, thereby realizing a soft start of the external fan against the wind. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, 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 these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram showing the assembly position of the louver blades in this invention;

[0040] Figure 2 This is a plan view of the external fan side in this invention;

[0041] Figure 3 This is a top view of the louver blades in this invention when their arrangement direction is parallel to the plane of the external fan.

[0042] Figure 4 This is a top view of the louver blades in this invention when their arrangement direction is perpendicular to the plane of the external fan.

[0043] Figure 5 This is the overall control logic of the control method for starting the external wind turbine against the wind in this invention;

[0044] Figure 6 This is a schematic diagram illustrating the specific process of the control method for starting Chinese and foreign wind turbines against the wind in this invention;

[0045] Among them, 1 is the external fan, 2 is the condenser, and 3 is the louver blade. Detailed Implementation

[0046] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0047] Therefore, a feature pointed out in this specification is used to describe one feature of one embodiment of the invention, and does not imply that every embodiment of the invention must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0048] The principles and structure of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0049] In windy environments, when the air conditioning system is powered off, the outdoor fan 1 of the air conditioning system is prone to reverse rotation due to the influence of external environmental factors. At this time, the air conditioning system will suffer losses due to the reverse rotation of the outdoor fan 1.

[0050] Based on the above issues, please refer to Figures 1 to 4 The present invention proposes an air conditioning system, which includes an outdoor fan 1 and a condenser 2, and also includes a windbreak structure disposed between the outdoor fan 1 and the condenser 3;

[0051] The windbreak structure has at least two assembly states: parallel to the plane where the external fan 1 is located, and perpendicular to the plane where the external fan 1 is located.

[0052] Here it is assumed that when the external environment is exposed to air, the air direction is towards the plane where the external fan 1 is located. When the plane where the windbreak structure is located is parallel to the plane where the external fan 1 is located, the windbreak structure can completely block the air from entering the external environment, thereby avoiding the problem of the external fan 1 reversing.

[0053] As for the case where the windbreak structure is perpendicular to the plane where the outdoor fan 1 is located, it is used for the process of the outdoor fan 1 supplying air after the air conditioning system is started.

[0054] As can be seen from the above settings, the windbreak structure in this invention can avoid the impact of external air intake on the external fan 1 and reduce the reverse rotation speed of the external fan 1 when the air conditioning system is powered off.

[0055] Please see Figure 1 and Figure 2 In this invention, the windbreak structure consists of multiple louver blades 3 and a motor that controls the rotation of all louver blades 3.

[0056] The motor can control the arrangement direction of the louver blades 3 to be parallel or perpendicular to the plane where the external fan 1 is located. When the air conditioning system is in a power-off state, the motor controls the arrangement direction of the louver blades 3 to be parallel to the plane where the external fan 1 is located.

[0057] Please see Figure 3 In this case, the louver blades 3 are arranged in a direction parallel to the plane where the external fan 1 is located. At this time, the louver blades 3 can completely block the external air intake, thus avoiding the influence of the external environment on the external fan 1 and preventing it from reversing.

[0058] Please see Figure 4 In this case, the arrangement direction of the louver blades 3 is perpendicular to the plane where the external fan 1 is located. (From this attachment...) Figure 4 It is quite obvious that the louver blades 3 cannot block the wind at this time. In this case, it is necessary to apply it to the situation where the outdoor fan 1 needs to ventilate normally, that is, when the air conditioning system is running normally and the outdoor fan 1 is supplying air normally.

[0059] The motor is in the above-mentioned attachment Figure 3 and appendix Figure 4 Not shown in the figure, it can be executed by a stepper motor, and the encoder feeds back the current rotation speed and rotation direction of the external fan 1 to the main board;

[0060] Appendix Figure 3 and attached Figure 4 The settings in the text are the two assembly states of the windbreak structure mentioned above. However, in actual applications, since the louver blade 3 is rotated by a motor, each angle corresponds to an assembly state. Therefore, the louver blade 3 actually has countless assembly states.

[0061] The windbreak structure in this invention has two assembly states: parallel to the plane where the external fan 1 is located, and perpendicular to the plane where the external fan 1 is located. This satisfies the above-mentioned windbreak requirements. The louver blade 3 is configured as in a preferred embodiment of this invention. In fact, as long as it has the above two assembly states, it should be within the protection scope of this invention.

[0062] The present invention employs a configuration of louver blades 3 and a stepper motor to achieve the two assembly states described above, avoiding the problem of the outdoor fan 1 reversing when the air conditioning system is powered off. Furthermore, when the outdoor fan 1 is started against the wind, the operating resistance of the outdoor fan 1 needs to be gradually adjusted. The present invention, through the setting of the stepper motor, can gradually adjust the angle of the louver blades 3, thereby adjusting the amount of external air intake and achieving the effect of gradually adjusting the operating resistance of the outdoor fan 1.

[0063] Based on the above-described air conditioning system setup, this invention also proposes a control method for starting the outdoor fan against the wind. Please refer to [link / reference needed]. Figure 5 It includes:

[0064] Step S1: Detect the rotation direction of the external fan 1. When the rotation direction of the external fan 1 is positive, proceed to step S2.

[0065] Step S2: Adjust the angle between the louver blades 3 and the plane where the external fan 1 is located in the windbreak structure, and the control duty cycle of the external fan 1, so that the speed of the external fan 1 reaches the first preset speed range.

[0066] Step S3: Using the control duty cycle of the external fan 1 and the speed of the external fan 1 as inputs, perform closed-loop control on the external fan 1;

[0067] Step S4: Detect the speed of the outdoor fan 1. When the speed of the outdoor fan 1 reaches the second preset speed range, turn on the compressor in the air conditioning system.

[0068] The control method for starting the external fan against the wind proposed in this invention combines the angle between the louver blades 3 and the plane where the external fan 1 is located, as well as the control duty cycle of the external fan 1, when adjusting the speed of the external fan 1. This allows for gradual adjustment of the operating speed of the external fan 1, thereby achieving soft start of the external fan 1 against the wind.

[0069] As can be seen from step S1 above, the prerequisite for entering step S3 under this step is that the rotation direction of the external fan 1 is positive. However, in actual application, even with the obstruction of the louver blades 3, the external fan 1 may still reverse. In this invention, step S2 is based on the external fan 1 already being in forward rotation or stopped. Therefore, step S1 proposed in this invention also needs to perform corresponding steps to be implemented when the external fan 1 is in reverse rotation, so that the external fan 1 returns to the forward rotation state or the stopped state.

[0070] To achieve the above objectives, step S1 in this invention further includes:

[0071] Step S11: When the rotation direction of the external fan 1 is reversed, increase the control duty cycle of the external fan 1;

[0072] Step S12: Detect whether the reverse rotation speed of the external fan 1 has decreased. If yes, proceed to step S13; otherwise, return to step S11.

[0073] Step S13: Maintain the control duty cycle of the external fan 1. When the rotation direction of the external fan 1 changes to forward or stops, proceed to step S2.

[0074] From step S11 to step S13, it can be seen that this part of the steps is a cyclic judgment process. If the reverse rotation speed of the external fan 1 does not decrease, the control duty cycle of the external fan 1 will be increased until the reverse rotation speed of the external fan 1 is detected to decrease.

[0075] Here, the control duty cycle of the external fan 1 is related to the speed supplied to the external fan 1 for forward rotation. Generally speaking, the higher the control duty cycle of the external fan 1, the higher the speed supplied to the external fan 1 for forward rotation. Therefore, by gradually increasing the control duty cycle of the external fan 1, the speed supplied to the external fan 1 for forward rotation will eventually be greater than the speed for reverse rotation, thereby reducing the speed of the external fan 1 for reverse rotation.

[0076] The reason for maintaining the control duty cycle of the external fan 1 by using the decrease in the reverse rotation speed as a sign, rather than using the occurrence of forward rotation or stoppage of the external fan 1, is that when the reverse rotation speed of the external fan 1 decreases, the actual speed supplied to the external fan 1 for forward rotation is already greater than the reverse rotation speed. At this time, the reverse rotation speed will gradually decrease and eventually put the external fan 1 into a forward rotation or stoppage state. If the control duty cycle of the external fan 1 is further increased, it will make the control duty cycle of the external fan 1 too large, affecting its normal use.

[0077] In other words, through the above-mentioned settings, the present invention enables the external fan 1 to enter step S2 in either forward or stopped state, thus ensuring the normal execution of the control process of the external fan 1.

[0078] Furthermore, in step S11, the control duty cycle of the external fan 1 satisfies the calculation model:

[0079]

[0080] Where D1 is the control duty cycle of the external fan 1 in step S1, D0 is the reference duty cycle, t1 is the control cycle, and n is the total judgment cycle;

[0081] The external fan 1 increases its control duty cycle by increasing the total judgment cycle.

[0082] Based on this calculation model, the adjustment process of the control duty cycle of the external wind turbine 1 in this invention can be specifically as follows:

[0083] At second 0, the current external fan 1 is in reverse rotation, n = t1, and at this time, D1 = D0. At second t1, if the current external fan 1 is still in reverse rotation and the speed has not decreased compared to the reverse rotation speed at second 0, then let n = t1 + t1, D1 = 2 * D0.

[0084] At the 2*t1 second, the reverse rotation speed decreases compared to the t1 second, so n does not increase and remains n = t1 + t1;

[0085] At the 3*t1 second, the reverse rotation speed has not decreased compared to the 2*t1 second, so n=t1+t1+t1, D1=3*D0, and so on, until the external fan 1 turns forward or stops.

[0086] Among them, the control duty cycle of the external fan 1 is the control quantity of the main board for the external fan 1. In a windy environment, the external fan 1 needs to overcome the reverse rotation caused by the external wind, so the duty cycle needs to be increased to achieve forward rotation. Based on the above calculation model, the present invention can gradually increase the control duty cycle of the external fan 1, so that the duty cycle reaches a suitable amount, and ultimately enables the external fan 1 to overcome the reverse rotation caused by the external wind.

[0087] As mentioned above, the adjustment of the rotational speed of the external fan 1 in step S2 of this invention is based on the angle between the louver blades 3 and the plane where the external fan 1 is located, and the control duty cycle of the external fan 1. To achieve the control of the above two parameters, this invention provides two adjustment models. The adjustment model for the angle between the louver blades 3 and the plane where the external fan 1 is located in the windbreak structure in step S2 is as follows:

[0088]

[0089] Where α is the angle between the louver blade 3 in the windbreak structure and the plane where the external fan 1 is located, k is the total number of stages of the external fan 1 starting against the wind, and k1 is the current stage of the external fan 1 starting against the wind.

[0090] The adjustment model for the control duty cycle of the external fan 1 in step S2 is as follows:

[0091]

[0092] Where D is the control duty cycle of the external fan 1 in step S2, and D1 is the control duty cycle of the external fan 1 in step S1. target k is the set duty cycle of the external fan 1 in the current gear, k is the total number of stages of the external fan 1 starting against the wind, and k1 is the current stage of the external fan 1 starting against the wind.

[0093] Based on the two adjustment models mentioned above, the control method for starting the external fan 1 against the wind proposed in this invention combines the angle between the louver blades 3 and the plane where the external fan 1 is located, as well as the control duty cycle of the external fan 1, when adjusting the speed of the external fan 1. This allows for gradual adjustment of the operating speed of the external fan 1, thereby achieving soft start of the external fan 1 against the wind.

[0094] As mentioned earlier, when adjusting the control duty cycle of the external fan 1 in step S2, the duty cycle at this time is related to the control duty cycle of the external fan 1 finally adjusted in step S1. Theoretically, when the current stage number of the external fan 1 starting against the wind reaches the total number of stages, D = D1 + D target At this point, the control duty cycle obtained through step S2 is greater than the first preset duty cycle. However, in practical applications, the wind speed in the external environment changes in real time and is not a fixed wind speed. Therefore, after completing the above adjustment process, the speed of the external fan 1 may still not reach the first preset speed range, and the control adjustment to step S3 is not satisfied. Based on this situation, step S2 provided by the present invention further includes:

[0095] Step S21: When the current stage number of the outdoor fan 1 starting against the wind is equal to the total number of stages of the outdoor fan starting against the wind, detect the current speed of the outdoor fan 1;

[0096] Step S22: Determine whether the current speed of the external fan 1 has reached the first preset speed range. If yes, proceed to step S3; otherwise, proceed to step S23.

[0097] Step S23: Continue to increase the control duty cycle of the external fan 1 in step S2, and each increase in duty cycle 1 is the reference duty cycle in step S1, and return to step S22.

[0098] By executing this part of the steps, the present invention can further improve the control duty cycle of the external fan 1 and ultimately make the speed of the external fan 1 reach the first preset speed, thereby ensuring the execution of step S3.

[0099] In this invention, the first preset rotational speed range is (0.8n). target ,∞), the second preset speed range is (0.95n target 1.05n target ), where n target The target speed of external fan 1.

[0100] Here, the first preset speed range is greater than 0.8 times the target speed of the external fan. At this time, the external fan 1 has been running relatively stably. Since the ultimate goal of this invention is to achieve the target speed, a more precise control strategy is required. Therefore, when the first preset speed range is reached, the invention is adjusted to a closed-loop control strategy, which has higher control precision. Here, the second preset range is the target speed range that needs to be controlled. In this invention, a 5% control error is set.

[0101] In other words, by setting the first preset speed range and the second preset speed range, the present invention divides the control stage of the present invention into two control stages. When the first preset speed range is reached, a closed-loop control strategy is adopted, which can improve the final control accuracy of the present invention and enable the external fan 1 to finally run within the target speed range.

[0102] Furthermore, in this invention, the closed-loop control strategy in step S3 is a PID control strategy.

[0103] Compared with traditional control strategies, PID control strategy has higher control accuracy and can make the speed of external fan 1 reach the target speed range.

[0104] Under its PID control strategy, the target speed of external fan 1 can be set to n. target The actual rotational speed is n, and the deviation value is Δn = n traget -n, the control duty cycle of external fan 1 is D, the reference duty cycle is D0, the control interval period is t3, and then the PID control strategy is executed with the following control model:

[0105] D=D0+Kp*Δn+Ki*△n*t3+Kd*(△n-△n0) / t3;

[0106] Based on the PID control strategy, this invention enables the external fan 1 to reach the target speed range.

[0107] Please see Figure 6 The specific control process for the external fan 1 in this invention is as follows:

[0108] When the air conditioning system is not started, the initial angle between the control louver blades 3 and the plane where the outdoor fan 1 is located is 0°, that is, they are set in parallel.

[0109] When the air conditioning system is started, that is, when the air conditioning remote control is selected in cooling mode and the power button is pressed;

[0110] Then, it begins to check whether the current rotation direction of the external fan 1 is reversed;

[0111] If so, let n = t1, and enter the control of step S1, using the PWM wave duty cycle on the motherboard to control the speed of the external fan 1;

[0112] After multiple cycles of adjustment, until the current speed of the external fan is either forward or stopped, the process of adjusting the angle between the louver blades 3 and the plane of the external fan 1, as well as the control duty cycle of the external fan 1, will begin. (If the current rotation direction of the external fan 1 is detected as forward, this step will be directly entered.)

[0113] After the adjustment process, it is determined whether the current speed has reached the first preset speed range. If not, the control duty cycle of the external fan 1 is increased. Otherwise, the speed of the external fan 1 is controlled by closed-loop PID.

[0114] The compressor is turned on when the current speed of the external fan 1 is within the second preset speed range.

[0115] In summary, based on the above-mentioned settings, the present invention has at least the following beneficial effects compared with the prior art:

[0116] 1. The present invention adds a windbreak structure between the outdoor fan and the condenser. When the air conditioning system is in a power-off state, the windbreak structure can control the arrangement direction of the louvers in the windbreak structure to be parallel to the plane where the outdoor fan is located. In this arrangement, the windbreak structure can block the external air intake, thereby reducing the reverse rotation speed of the outdoor fan when the air conditioning system is in a power-off state.

[0117] 2. This invention proposes a control method for starting an external fan against the wind, which can gradually adjust the operating resistance of the external fan, thereby realizing a soft start of the external fan against the wind.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for starting the outdoor fan of an air conditioning system against the wind, characterized in that, include: Step S1: Detect the rotation direction of the external fan. When the rotation direction of the external fan is positive, proceed to step S2. Step S2: Adjust the angle between the louver blades in the windbreak structure and the plane where the external fan is located, as well as the control duty cycle of the external fan, so that the speed of the external fan reaches the first preset speed range; Step S3: Using the control duty cycle and the rotational speed of the external fan as inputs, perform closed-loop control on the external fan; Step S4: Detect the speed of the outdoor fan. When the speed of the outdoor fan reaches the second preset speed range, turn on the compressor in the air conditioning system. Step S1 further includes: Step S11: When the rotation direction of the external fan is reversed, increase the control duty cycle of the external fan; Step S12: Detect whether the reverse rotation speed of the external fan has decreased. If yes, proceed to step S13; otherwise, return to step S11. Step S13: Maintain the control duty cycle of the external fan. When the rotation direction of the external fan changes to forward or stops, proceed to step S2. The closed-loop control strategy in step S3 is a PID control strategy, and the calculation model of the PID control strategy is: D=D0+Kp*Δn+Ki*Δn*t3+Kd*(Δn-Δn0) / t3; Wherein, D is the control duty cycle of the external fan, D0 is the reference duty cycle of the external fan, Δn is the deviation between the target speed and the actual speed of the external fan, and t3 is the control interval period; The windbreak structure is located between the external fan and the condenser.

2. The control method for starting the external fan against the wind according to claim 1, characterized in that, In step S11, the control duty cycle of the external fan satisfies the calculation model: ； Wherein, D1 is the control duty cycle of the external fan in step S1, D0 is the reference duty cycle, t1 is the control cycle, and n is the total judgment cycle; The external fan increases its control duty cycle by increasing the total judgment cycle. The method for increasing the total judgment period is as follows: set the initial value of the total judgment period to t1, and after each t1, determine whether the reverse rotation speed of the external fan has decreased. If so, maintain the total judgment period unchanged; otherwise, increase the total judgment period by t1.

3. The control method for starting the external fan against the wind according to claim 1, characterized in that, The adjustment model for the angle between the louver blades in the windbreak structure and the plane where the external fan is located in step S2 is as follows: ； in, The angle between the louver blades in the windbreak structure and the plane where the external fan is located, k is the total number of stages of the external fan starting against the wind, and k1 is the current stage of the external fan starting against the wind.

4. The control method for starting the external fan against the wind according to claim 2, characterized in that, The adjustment model for the control duty cycle of the external fan in step S2 is as follows: ； Wherein, D is the control duty cycle of the external fan in step S2, and D1 is the control duty cycle of the external fan in step S1. k is the set duty cycle of the external fan in the current gear, k is the total number of stages of the external fan starting against the wind, and k1 is the current stage of the external fan starting against the wind.

5. The control method for starting the external fan against the wind according to claim 4, characterized in that, Step S2 further includes: Step S21: When the current stage number of the outdoor fan starting against the wind is equal to the total number of stages of the outdoor fan starting against the wind, detect the current speed of the outdoor fan; Step S22: Determine whether the current speed of the external fan has reached the first preset speed range. If yes, proceed to step S3; otherwise, proceed to step S23. Step S23: Continue to increase the control duty cycle of the external fan in step S2, and each increase in duty cycle is the reference duty cycle in step S1, and return to step S22.

6. The control method for starting the external fan against the wind according to claim 1, characterized in that, The first preset speed range is (0.8n). target ,∞), the second preset speed range is (0.95n target 1.05n target ), where n target The target rotational speed of the external fan.

7. An air conditioning system employing the control method as described in any one of claims 1 to 6, comprising an outdoor fan and a condenser, characterized in that, The windbreak structure has at least two assembly states: parallel to the plane where the external fan is located, and perpendicular to the plane where the external fan is located.

8. The air conditioning system according to claim 7, characterized in that, The windbreak structure includes multiple louver blades and a motor that controls the rotation of all the louver blades; The motor can control the arrangement direction of the louvers to be parallel or perpendicular to the plane where the external fan is located, and when the air conditioning system is in a power-off state, the motor controls the arrangement direction of the louvers to be parallel to the plane where the external fan is located.

Images