Fan starting control method and fan system

Abstract

The application discloses a fan starting control method and a fan system, wherein the fan system has a first starting stage from power-on to executing a starting instruction and a second starting stage from executing the starting instruction to stable operation; the fan starting control method comprises the following steps: detecting an electrical parameter of the fan when the fan is in the first starting stage; judging whether the interference current of the fan meets a starting condition according to the electrical parameter; and controlling the fan to start when it is judged that the interference current meets the starting condition. Compared with the prior art, the application can judge whether there is a large interference current in the fan, and control whether the fan starts according to the judgment result, thereby avoiding the false starting or shutdown of the fan caused by the interference current.

Description

Technical Field

[0001] This invention relates to the field of wind turbine control, and in particular to a wind turbine start-up control method and wind turbine system. Background Technology

[0002] With the increasing demand for energy conservation and emission reduction, energy-efficient air conditioners have become a major design focus. Their fan systems and compressors typically use an integrated drive board for control, sharing a controller. The compressor's startup process involves three stages: from standstill to open-loop operation and finally to closed-loop operation. During open-loop operation, the compressor current is uncontrolled, resulting in significant current fluctuations during startup under heavy load conditions. Furthermore, due to factors such as the controller installation environment, power supply voltage fluctuations, and wiring interference, pulse interference currents with the same frequency as the compressor's operation may be generated in the fan windings. Under certain operating conditions, this interference current can have a high amplitude, easily causing the fan to misinterpret an overcurrent fault during the initial startup phase, leading to fan shutdown and the need for restarting, thus affecting the system's stability and efficiency.

[0003] Existing wind turbine start-up control methods typically employ fixed start-up strategies or simple current threshold judgment methods, lacking mechanisms for identifying and responding to interference currents. This results in a low start-up success rate for wind turbines under complex operating conditions, affecting the overall system reliability.

[0004] Therefore, how to design a fan start-up control method and fan system that can avoid the fan from starting incorrectly or failing to start due to excessive interference current is a technical problem that the industry urgently needs to solve. Summary of the Invention

[0005] In view of the problem that large interference current in the existing technology causes the fan to start falsely or fail to start, the present invention proposes a fan start control method and a fan system.

[0006] The technical solution of this invention is to propose a fan start-up control method for driving a fan system controlled by an integrated board. The fan has a first start-up stage and a second start-up stage. The fan start-up control method includes:

[0007] When the fan is in the first start-up phase, the electrical parameters of the fan are detected;

[0008] Determine whether the interference current of the fan meets the starting conditions based on the electrical parameters.

[0009] When the determination is yes, control the fan to start.

[0010] Furthermore, the fan start-up control method also includes:

[0011] When the fan is in the second start-up phase, it is determined whether the compressor in the fan system is operating in a closed loop;

[0012] If so, the fan is controlled to enter a closed-loop control mode with frequency feedback regulation;

[0013] If not, the fan is controlled to enter an open-loop control mode with uncontrolled frequency regulation.

[0014] Furthermore, the electrical parameters are the maximum phase current and minimum phase current of the fan;

[0015] Determining whether the interference current of the fan meets the starting conditions based on the electrical parameters includes:

[0016] Calculate the absolute value of the maximum phase current and the absolute value of the minimum phase current;

[0017] Determine whether the absolute value of the maximum phase current and the absolute value of the minimum phase current are both greater than the threshold current.

[0018] If not, then the fan is determined to meet the start-up conditions.

[0019] Furthermore, before determining that the fan meets the start-up conditions, the process also includes:

[0020] The duration during which the absolute value of the maximum phase current and the absolute value of the minimum phase current are not both greater than the threshold current;

[0021] Determine whether the duration is greater than a threshold time;

[0022] If so, the fan is determined to meet the start-up conditions.

[0023] Furthermore, when the wind turbine enters the closed-loop control mode, the wind turbine start-up control method includes:

[0024] Detect the current operating frequency of the fan;

[0025] Calculate the difference between the current operating frequency and the target operating frequency;

[0026] The current operating frequency of the fan is adjusted based on the difference.

[0027] Furthermore, adjusting the current operating frequency of the fan based on the difference includes:

[0028] When the difference is greater than zero, the current operating frequency of the fan is reduced;

[0029] When the difference is less than zero, the current operating frequency of the fan is increased.

[0030] Furthermore, when the wind turbine enters the open-loop control mode, the wind turbine start-up control method includes:

[0031] The operating frequency of the fan is uncontrolled, and the operating current of the fan is adjusted according to the reference current of the fan in the first start-up stage and the maximum phase current of the fan.

[0032] Furthermore, the adjustment model for adjusting the operating current of the fan based on the maximum phase current of the fan is as follows:

[0033] i = IEFmax - k * Imax;

[0034] Where i is the operating current of the wind turbine, IREFmax is the maximum reference current of the wind turbine in the first startup phase, Imax is the maximum phase current, and k is an adjustment coefficient greater than 1.

[0035] Furthermore, adjusting the operating current of the fan according to the maximum phase current of the fan also includes:

[0036] Determine whether the operating current of the fan is less than the minimum reference current of the fan during the first startup phase;

[0037] If so, the operating current of the fan is controlled to be the minimum value of the reference current;

[0038] If not, the operating current of the fan is adjusted using the aforementioned adjustment model.

[0039] The present invention also proposes a fan system employing the above-described fan start-up control method, wherein the fan system has a controller for simultaneously controlling the fan and the compressor;

[0040] When the fan is in the first startup phase, the controller can detect the electrical parameters of the fan and control whether the fan starts based on the electrical parameters;

[0041] When the fan is in the second start-up phase, the controller can switch the fan to either closed-loop control mode or open-loop control mode depending on whether the compressor is operating in a closed loop.

[0042] Compared with the prior art, the present invention has at least the following beneficial effects:

[0043] 1. This invention can determine whether there is a large interference current based on the electrical parameters of the fan, and control whether the fan starts based on the determination result, thus avoiding the fan from starting or stopping due to interference current.

[0044] 2. The present invention has an open-loop operation mode when the fan just starts and enters the second start-up stage, which can adapt to the dynamic changes of the compressor during the start-up process;

[0045] 3. After the compressor enters closed-loop operation, the present invention has a closed-loop operation mode, which can realize normal speed regulation and control of the fan. Attached Figure Description

[0046] 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.

[0047] Figure 1 This is a control flowchart of the first startup phase of the present invention;

[0048] Figure 2 This is a control flowchart of the second startup phase of the present invention;

[0049] Figure 3 This is a flowchart illustrating the process of determining whether a large interference current exists during the first startup phase of the present invention.

[0050] Figure 4 This is a specific control flow in a preferred embodiment of the present invention. Detailed Implementation

[0051] 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.

[0052] 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.

[0053] The principles and structure of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0054] With the increasing demand for energy conservation and emission reduction, energy-efficient air conditioners have become a major design focus. Their fan systems and compressors typically use an integrated drive board for control, sharing a controller. The compressor's startup process involves three stages: from standstill to open-loop operation and finally to closed-loop operation. During open-loop operation, the compressor current is uncontrolled, resulting in significant current fluctuations during startup under heavy load conditions. Furthermore, due to factors such as the controller installation environment, power supply voltage fluctuations, and wiring interference, pulse interference currents with the same frequency as the compressor's operation may be generated in the fan windings. Under certain operating conditions, this interference current can have a high amplitude, easily causing the fan to misinterpret an overcurrent fault during the initial startup phase, leading to fan shutdown and the need for restarting, thus affecting the system's stability and efficiency.

[0055] To address the aforementioned problems, the design concept of this invention is to determine whether there is a large interference current in the fan by detecting the electrical parameters of the fan, and then start the fan when it is determined that there is no large interference current in the fan, thereby avoiding the fan from being started or stopped due to interference current.

[0056] Please see Figure 1 Based on the above design concept, this invention proposes a fan start-up control method, which includes:

[0057] When the fan is in the first startup phase, the fan's electrical parameters are checked;

[0058] Determine whether the fan's interference current meets the starting conditions based on electrical parameters;

[0059] When the determination is yes, the control fan is started.

[0060] It should be noted that the wind turbine startup process in this invention is divided into two stages: the first startup stage and the second startup stage. The first startup stage is the stage from when the wind turbine is powered on to when it executes the startup command, and the second startup stage is the stage from when the wind turbine executes the startup command to when it is running stably.

[0061] The aforementioned wind turbine has a large interference current, which can cause the wind turbine to stop and need to be restarted. This mainly occurs in the first startup stage. Therefore, in this invention, the detection of electrical parameters is set in the first startup stage to determine whether the interference current of the wind turbine meets the startup conditions.

[0062] Whether the interference current of the fan meets the starting conditions, that is, whether there is an interference current in the fan that would cause the fan to stop, is determined by the present invention through electrical parameters. Only when the determination is yes will the fan be controlled to start. This ensures that there is no large interference current that would cause the fan to stop when it starts.

[0063] Accordingly, the present invention can achieve the beneficial effects described above:

[0064] This invention can determine whether there is a large interference current based on the electrical parameters of the fan, and control whether the fan starts based on the judgment result, thus avoiding the fan from starting or stopping due to interference current.

[0065] As mentioned above, this invention divides the fan startup process into two stages. In the first startup stage, the aforementioned strategy can prevent the fan from starting or stopping incorrectly due to interference current. In the second startup stage, since the fan has just started, there will be significant current fluctuations. If the current is not controlled, the fan may stop due to excessive current. To avoid this problem, please refer to [link to relevant documentation]. Figure 2 The wind turbine start-up control method proposed in this invention also includes:

[0066] When the fan is in the second startup phase, determine whether the compressor in the fan system is operating in a closed loop.

[0067] If so, the fan will be controlled to enter a closed-loop control mode with frequency feedback regulation;

[0068] If not, the fan will be controlled to enter an open-loop control mode with uncontrolled frequency regulation.

[0069] Among them, the closed-loop control mode refers to the control mode that adjusts the operating frequency of the fan based on the current operating frequency of the fan. This closed-loop control mode is mainly used to achieve precise control of the fan. This is because whether it is a compressor or a fan, the ultimate goal of control is to accurately control the operating frequency. Therefore, the fan eventually needs to return to this closed-loop control mode.

[0070] Open-loop control mode does not control the operating frequency of the fan, but only controls the operating current of the fan. It is mainly used to avoid the problem of excessive current in the fan causing shutdown.

[0071] As mentioned above, the fan system used in this invention is a fan system controlled by an integrated drive board. Its compressor and fan share the same controller. Before entering closed-loop control, the compressor current is uncontrolled and there will be large current fluctuations in the open-loop control mode. Therefore, in this process, it is necessary to avoid the large current fluctuations affecting the operation of the fan and causing the fan to stop. At this time, the open-loop control mode is entered, which mainly controls the operating current of the fan to avoid the fan stopping.

[0072] After the compressor enters closed-loop control, the compressor current is controllable and the entire system operates relatively stably. Since the ultimate goal of control is to precisely control the operating frequency of the fan, after determining that the compressor has entered closed-loop control, it is necessary to control the fan to enter closed-loop control mode.

[0073] Based on this configuration, the present invention can adapt to the dynamic changes of the compressor during the startup process when the fan just starts and enters the second startup stage, avoiding the problem of the fan stopping due to large current. At the same time, it can achieve normal speed regulation control of the fan after the compressor enters closed-loop operation.

[0074] The above describes the overall control logic for the fan in the first and second startup stages of this invention. The specific steps for each stage are described in detail below:

[0075] Please see Figure 3 For the first startup phase, the above electrical parameters are the maximum and minimum phase currents of the fan.

[0076] Determine whether the fan's interference current meets the starting conditions based on electrical parameters, including:

[0077] Calculate the absolute values ​​of the maximum and minimum phase currents;

[0078] Determine whether the absolute values ​​of the maximum and minimum phase currents are simultaneously greater than the threshold current.

[0079] If not, then the fan is deemed to meet the start-up conditions.

[0080] The reason for using absolute values ​​for comparison here is that, for the phase current of a motor, the maximum phase current is generally positive and the minimum phase current is generally negative. However, the sign of the phase current generally only reflects the direction of the current and does not reflect the magnitude of the current intensity. Therefore, it is necessary to use absolute values ​​for comparison.

[0081] The reason for using "whether the absolute value of the maximum phase current and the absolute value of the minimum phase current are simultaneously greater than the threshold current" in this invention is that when there is interference current in the fan, it will be superimposed on the normal fan current. The superposition amplitude of interference current on the maximum phase current and the minimum phase current is the same. Therefore, the situation may occur where the absolute value of the maximum phase current and the absolute value of the minimum phase current are simultaneously greater than the threshold current.

[0082] The threshold current is set here to avoid the influence of the maximum and minimum phase current of the fan itself on the judgment result. If the threshold current is set too small, the maximum and minimum phase current of the fan itself may exceed the threshold current when there is no interference current in the fan, which may lead to a false judgment that there is interference current in the fan.

[0083] Furthermore, in some embodiments, if the interference current is small and will not affect the operation of the fan, the interference current can be ignored. Therefore, the threshold current setting can be set according to the actual requirements for the interference current. For example, if the fan will only stop when the interference current is too large, the current threshold can be set based on the large interference current.

[0084] The above steps are also the control strategy in the first startup stage of this invention. Through this part of the scheme, this invention can ensure that there is no large interference current when the wind turbine starts up, thereby avoiding the problem of wind turbine misstart or shutdown caused by interference current.

[0085] Furthermore, during the fan startup process, there may be instantaneous current fluctuations, which could lead to the fan being deemed to meet the startup conditions based on the aforementioned judgment logic, even though interference current exists in the actual fan. If the fan is started at this time, it may shut down due to the interference current. To avoid this situation, the present invention further includes, before determining whether the fan meets the startup conditions:

[0086] The duration during which the absolute values ​​of the maximum and minimum phase currents are not simultaneously greater than the threshold current;

[0087] Determine if the duration exceeds the threshold time;

[0088] If so, the fan is deemed to meet the startup conditions;

[0089] As mentioned above, the determination of whether the wind turbine meets the starting conditions is based on whether the absolute value of the maximum phase current and the absolute value of the minimum phase current are simultaneously greater than the threshold current. If the determination is no, the starting conditions are considered to be met. That is, the wind turbine meets the starting conditions when the absolute value of the maximum phase current and the absolute value of the minimum phase current are not simultaneously greater than the threshold current.

[0090] Therefore, in this step of the present invention, by detecting the duration during which "the absolute values ​​of the maximum phase current and the minimum phase current are not simultaneously greater than the threshold current", the duration during which the fan meets the starting conditions can be determined. For the instantaneous current fluctuations that occur during the fan startup process, the duration is generally short and will not allow the fan to meet the starting conditions for a long time. Therefore, by detecting the duration during which the absolute values ​​of the maximum phase current and the minimum phase current are not simultaneously greater than the threshold current, and then determining whether the duration is greater than the threshold time, the present invention can further determine whether the fan meets the starting conditions, thus avoiding misjudgments caused by instantaneous current fluctuations.

[0091] In other words, through the above-mentioned judgment logic, the present invention can avoid the occurrence of misjudgment problems, ensure that there is no large interference current when the fan starts, and avoid the fan starting or stopping due to interference current.

[0092] As mentioned above, for the second startup phase, this invention switches the fan to either a closed-loop control mode or an open-loop control mode based on whether the compressor is operating in a closed loop. The closed-loop control mode is executed after the compressor has entered closed-loop operation, while the open-loop control mode is executed before the compressor has entered closed-loop operation. These two modes are explained below:

[0093] When the wind turbine enters closed-loop control mode, the wind turbine start-up control methods include:

[0094] Detect the current operating frequency of the fan;

[0095] Calculate the difference between the current operating frequency and the target operating frequency;

[0096] Adjust the current operating frequency of the fan based on the difference.

[0097] This part of the control is to precisely control the operating frequency of the fan. As mentioned earlier, whether it is a compressor or a fan, the ultimate goal of the control is to achieve precise control of the operating frequency, thereby adjusting the operating state of the fan, such as the fan speed.

[0098] This closed-loop control mode compares the current operating frequency with the target operating frequency, obtains corresponding feedback, and then adjusts the current operating frequency before repeating the cycle. Because this control method involves a continuous closed-loop adjustment process, it ensures control accuracy. Furthermore, this control mode has strong anti-interference capabilities; even if the current operating frequency fluctuates, it can promptly adjust based on the difference between the current and target operating frequencies, thereby achieving precise control of the wind turbine's operation.

[0099] Based on this control mode, the present invention can achieve precise speed control of the fan.

[0100] In the aforementioned closed-loop control mode, adjusting the current operating frequency of the fan based on the difference includes:

[0101] When the difference is greater than zero, reduce the current operating frequency of the fan;

[0102] When the difference is less than zero, increase the current operating frequency of the fan.

[0103] Here, when the difference between the current operating frequency and the target operating frequency is greater than zero, it indicates that the current operating frequency is higher than the target operating frequency. In this case, the current operating frequency needs to be reduced in order for the wind turbine to operate at the target operating frequency.

[0104] Similarly, when the difference between the current operating frequency and the target operating frequency is less than zero, it indicates that the current operating frequency is lower than the target operating frequency. In this case, the current operating frequency needs to be increased in order for the fan to operate at the target operating frequency.

[0105] This part of the control is an important part of the closed-loop control mode. It continuously adjusts the current operating frequency by using the difference between the current operating frequency and the target operating frequency, so that the entire control process forms a closed loop. This ensures that the current operating frequency of the fan is eventually at the target operating frequency. Moreover, because this control process involves multiple closed-loop adjustments, its control accuracy is higher and its anti-interference capability is stronger.

[0106] Furthermore, when the wind turbine enters open-loop control mode, the wind turbine start-up control method includes:

[0107] The operating frequency of the fan is uncontrolled, and the operating current of the fan is adjusted according to the reference current and the maximum phase current of the fan during the first start-up phase.

[0108] The reason for adopting uncontrolled operation of the fan frequency here is that when the fan is first started, the operating frequency is low and the operating current is small but fluctuates greatly. Conventional control algorithms cannot accurately control and detect the fan speed based on the operating frequency. At the same time, due to the large current fluctuation and the fact that the compressor has not entered closed-loop operation, the operation of the fan will be affected. Therefore, the key to control at this time is to avoid the fan operating current being too large, which would cause the fan to shut down.

[0109] The reason for adjusting the operating current of the fan based on the reference current and the maximum phase current of the fan during the first startup phase is that when there is interference current in the fan, it will be superimposed on the maximum phase current. Therefore, when adjusting the operating current of the fan, this interference current needs to be subtracted from the reference current.

[0110] Since the maximum phase current is detected before the fan starts, the maximum phase current of the fan is actually the interference current. Therefore, this interference current needs to be subtracted from the reference current to control the operating current.

[0111] In other words, based on this control method, the present invention can adjust the operating current of the fan according to the actual interference of the fan, so that the fan can maintain a stable and controllable operating state with an appropriate current during the first start-up stage of the compressor, and avoid shutdown due to excessive current.

[0112] Specifically, the adjustment model for regulating the operating current of the fan based on the maximum phase current of the fan is as follows:

[0113] i = IEFmax - k * Imax;

[0114] Where i is the operating current of the wind turbine, IREFmax is the maximum reference current of the wind turbine in the first startup stage, Imax is the maximum phase current, and k is an adjustment coefficient greater than 1.

[0115] When interference current exists, it will be superimposed on the normal fan current. Therefore, by adjusting it using the above formula, the larger the maximum phase current value, the larger the corresponding interference current value, and the smaller the corresponding operating current will be. This ensures that the operating current of the fan will not exceed the overcurrent protection value of the fan after the interference current is superimposed.

[0116] In other words, by adjusting the operating current of the fan based on the above adjustment model, the problem of the fan shutting down due to interference current can be avoided.

[0117] Furthermore, the above adjustment process, which adjusts the operating current of the fan according to the maximum phase current of the fan, also includes:

[0118] Determine whether the operating current of the fan is less than the minimum reference current of the fan in the first startup phase;

[0119] If so, the operating current of the control fan is set to the minimum reference current.

[0120] If not, adjust the operating current of the fan by adjusting the model.

[0121] Setting this minimum reference current value here ensures that the operating current is within a suitable range, thereby guaranteeing that the fan can start and operate normally.

[0122] The following is in conjunction with the appendix Figure 4 The body control process of the present invention will be described, and its specific steps are as follows:

[0123] Fan start-up;

[0124] Detect the phase current of the fan and calculate |Imax| and |Imin|; here, Imxa is the maximum phase current of the fan, Imin is the minimum phase current of the fan, |Imax| is the absolute value of the maximum phase current of the fan, and |Imin| is the absolute value of the minimum phase current of the fan. This part is equivalent to the steps in the previous text to calculate the absolute values ​​of the maximum and minimum phase currents.

[0125] |Imax|>a and |Imin|>a? Here, a is the threshold current mentioned above. This part is equivalent to the step in the previous text to determine whether the absolute value of the maximum phase current and the absolute value of the minimum phase current are simultaneously greater than the threshold current. If the determination is yes, it indicates that there is a large interference current in the fan, and it is necessary to return to the fan start-up step. If the determination is no, it enters the step of preventing false judgment.

[0126] Timing t; This part is equivalent to the duration during which the absolute values ​​of the maximum and minimum phase currents are not simultaneously greater than the threshold current, as mentioned earlier. Here, t is this duration.

[0127] t>T? This part is equivalent to the step in the previous text that determines whether the duration is greater than the threshold time, where T is the threshold time.

[0128] Fan start-up;

[0129] Set the fan operating current i = IREFmax - k * Imax; this part is equivalent to the steps in the previous text to adjust the model control operating current when the fan is in open-loop control mode;

[0130] Is the compressor entering closed-loop operation? This part is equivalent to the step in the previous text to determine whether the compressor is operating in closed-loop mode. If the determination is no, the fan will continue to run in open-loop mode; otherwise, the fan will be controlled to enter closed-loop control mode.

[0131] The fan enters closed-loop control mode; this part means controlling the fan to enter closed-loop control mode when the compressor is running in closed loop.

[0132] Based on the above control process, the present invention has at least the following beneficial effects:

[0133] 1. This invention can determine whether there is a large interference current based on the electrical parameters of the fan, and control whether the fan starts based on the determination result, thus avoiding the fan from starting or stopping due to interference current.

[0134] 2. The present invention has an open-loop operation mode when the fan just starts and enters the second start-up stage, which can adapt to the dynamic changes of the compressor during the start-up process;

[0135] 3. After the compressor enters closed-loop operation, the present invention has a closed-loop operation mode, which can realize normal speed regulation and control of the fan.

[0136] The present invention also proposes a fan system employing the above-described fan start-up control method, wherein the fan system has a controller for simultaneously controlling the fan and the compressor;

[0137] During the first startup phase of the fan, the controller can detect the fan's electrical parameters and control whether the fan starts based on these parameters.

[0138] When the fan is in the second startup phase, the controller can switch the fan to either closed-loop control mode or open-loop control mode depending on whether the compressor is operating in a closed loop.

[0139] The above are merely preferred embodiments of the present invention and are 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 fan start-up control method for driving an integrated board controlled fan system, the fan system having a first start-up phase from power-up to execution of a start-up instruction, and a second start-up phase from execution of the start-up instruction to stable operation, characterized by, The fan starting control method comprises: detecting an electrical parameter of the fan when the fan is in the first starting stage; judging whether the interference current of the fan meets a starting condition according to the electrical parameter; controlling the fan to start when it is judged that the interference current of the fan meets the starting condition; the electrical parameter is a maximum phase current and a minimum phase current of the fan; judging whether the interference current of the fan meets a starting condition according to the electrical parameter comprises: calculating an absolute value of the maximum phase current and an absolute value of the minimum phase current; judging whether the absolute value of the maximum phase current and the absolute value of the minimum phase current are both greater than a threshold current; if not, it is judged that the fan meets the starting condition.

2. The fan start-up control method according to claim 1, characterized by, The fan starting control method further comprises: judging whether a compressor in the fan system is in closed-loop operation when the fan is in the second starting stage; if yes, controlling the fan to enter a closed-loop control mode of frequency feedback regulation; if not, controlling the fan to enter an open-loop control mode of frequency non-control regulation.

3. The fan start-up control method according to claim 1, characterized by, Before it is judged that the fan meets the starting condition, the method further comprises: detecting a duration that the absolute value of the maximum phase current and the absolute value of the minimum phase current are not greater than the threshold current; judging whether the duration is greater than a threshold time; if yes, it is judged that the fan meets the starting condition.

4. The fan start-up control method according to claim 2, characterized by, When the fan enters the closed-loop control mode, the fan starting control method comprises: detecting a current operating frequency of the fan; calculating a difference between the current operating frequency and a target operating frequency; adjusting the current operating frequency of the fan according to the difference.

5. The fan start-up control method according to claim 4, characterized by, Adjusting the current operating frequency of the fan according to the difference comprises: when the difference is greater than zero, decreasing the current operating frequency of the fan; when the difference is less than zero, increasing the current operating frequency of the fan.

6. The fan start-up control method according to claim 2, characterized by When the fan enters the open-loop control mode, the fan starting control method comprises: adopting non-control operation for the operating frequency of the fan, and adjusting the operating current of the fan according to a reference current of the fan in the first starting stage and the maximum phase current of the fan.

7. The fan start-up control method according to claim 6, characterized by, The adjustment model for adjusting the operating current of the fan according to the maximum phase current of the fan is: i = IREFmax - k * Imax; wherein i is the operating current of the fan, IREFmax is the maximum value of the reference current of the fan in the first starting stage, Imax is the maximum phase current, and k is an adjustment coefficient greater than 1.

8. The fan start-up control method according to claim 7, characterized by, Adjusting the operating current of the fan according to the maximum phase current of the fan further comprises: judging whether the operating current of the fan is less than a minimum value of the reference current of the fan in the first starting stage; if yes, controlling the operating current of the fan to be the minimum value of the reference current; if not, adjusting the operating current of the fan by the adjustment model.

9. A blower system employing the blower start-up control method according to any one of claims 1 to 8, characterized by The fan system has a controller for simultaneously controlling the fan and the compressor; when the fan is in the first starting stage, the controller can detect an electrical parameter of the fan, and control whether the fan starts according to the electrical parameter; When the fan is in the second starting stage, the controller can switch the fan into a closed-loop control mode or an open-loop control mode according to whether the compressor is running in a closed loop.

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