Control device and method for upwind starting of speed sensorless EC fan

Abstract

The invention relates to the technical field of fans, in particular to a control device and method for upwind starting of a speed sensorless EC fan, and the device comprises an observer module which collects fan data; the rotating speed detection module is used for comparing the rotating speed of the fan with a preset rotating speed threshold value and sending a braking signal when the threshold value is exceeded; the wind direction judgment module judges the initial rotating direction of a wind wheel, and when it is judged that the current rotating direction of the fan is reverse rotation, a braking signal is sent; the braking module is fixed on the outer shell and is used for braking the fan rotating shaft when receiving the braking signals from the rotating speed detection module and the wind direction judgment module at the same time; and the control module is used for receiving signals from the rotating speed detection module and the wind direction judgment module and correcting the observer module by dynamically adjusting the driving frequency. Reliable reversal protection can be achieved without increasing hardware cost, the failure risk of a physical sensor in a dense building environment is avoided, and meanwhile the structural damage risk caused by passive reversal overspeed due to strong headwind to equipment is eliminated.

Description

Technical Field

[0001] This invention relates to the field of wind turbine technology, and in particular to a control device and method for starting an EC wind turbine against the wind without a speed sensor. Background Technology

[0002] In densely built-up urban environments, complex wind field structures pose significant challenges to wind turbine operation. The canyon effect between buildings can significantly accelerate local wind speeds, while strong eddies and gusts with changing directions are easily generated at building corners and in open spaces. When a wind turbine encounters a sudden, strong reverse airflow, it may experience passive reversal, causing its rotational speed to exceed the safety threshold of its mechanical structure or electrical system within a very short time, directly threatening system reliability.

[0003] In this scenario, passive reverse rotation and overspeeding of wind turbines has become a core safety hazard. Traditional monitoring methods face significant limitations: equipment is densely distributed in the roof space, and mechanical anemometers or photoelectric encoders are easily affected by physical obstructions and mechanical vibrations, especially in harsh conditions such as rain, snow, and dust, making it difficult to accurately detect the reverse rotation state in real time. Physical encoders also pose a double risk: they may be damaged by mechanical impact during reverse rotation and overspeeding, or the braking command may be delayed due to signal transmission delays, further amplifying the probability of failure.

[0004] To ensure the long-term stable operation of fresh air systems in high-density urban building complexes and improve maintenance efficiency, it is urgent to develop a fan safety protection system based on speed-sensorless technology that integrates real-time monitoring of headwind conditions and intelligent braking control functions. This system aims to eliminate the risk of structural damage to equipment caused by passive reverse overspeed due to strong headwinds. Summary of the Invention

[0005] The purpose of this invention is to provide a control device and method for starting an EC wind turbine against the wind without a speed sensor, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A control device for starting an EC fan without a speed sensor against the wind includes:

[0008] The observer module is used to collect wind turbine data; wherein, the wind turbine data includes: wind turbine speed, angle, and back electromotive force;

[0009] The speed detection module is used to compare the fan speed with a preset speed threshold, and send a braking signal when the preset speed threshold is exceeded.

[0010] The wind direction determination module is used to determine the initial rotation of the wind turbine. When it is determined that the wind turbine is currently rotating in the opposite direction, a braking signal is sent.

[0011] The braking module, fixed on the outer housing, is used to receive braking signals from the speed detection module and the wind direction judgment module. When braking signals are received from both modules at the same time, the fan shaft is braked.

[0012] The control module receives signals from the speed detection module and the wind direction judgment module, and corrects the observer module by dynamically adjusting the drive frequency.

[0013] Optionally, the observer module employs an adaptive sliding mode observer, constructing a dynamic equation for the sliding surface based on the motor stator current and voltage signals. It ensures system stability by designing a Lyapunov function with the stator current error as the sliding surface and uses an adaptive algorithm to dynamically adjust the observer switching gain online. Simultaneously, a saturation function is introduced to replace the sign function for smoothing and filtering the observer output. Combined with the PWM drive frequency parameters transmitted by the control module, real-time high-precision estimation of rotor speed and position information is performed, and the optimized estimation results are transmitted to the speed detection module.

[0014] Optionally, the observer module includes:

[0015] The back electromotive force observation unit is used to acquire the back electromotive force according to the current error equation;

[0016] The sliding surface unit generates the sliding surface state through real-time integration of the current error, and its output is used to control the gain of the observer module and the calculation of the back electromotive force.

[0017] The parameter adaptive unit, based on the sliding surface state, uses Lyapunov functions and dynamically adjusts the gain of the observer module by setting stability conditions and parameter update laws.

[0018] Optionally, the wind direction determination module injects a high-frequency square wave pulse of preset amplitude into the stator winding, collects the three-phase current response signal and decouples it into dq-axis components through coordinate transformation, determines the initial direction of the wind turbine based on the phase characteristic difference of the d-axis current ripple amplitude, and sends a braking signal to the braking module when a reverse rotation feature is detected.

[0019] Optionally, the braking module includes: an electromagnet, a spring assembly, and a brake pad; wherein the brake pad is located on both sides of the fan shaft, the electromagnet is fixed on the side of the brake pad away from the fan shaft, one end of the spring assembly is connected to the side of the brake pad away from the fan shaft, and the other end is fixed to the outer housing;

[0020] When not braking, the spring assembly separates the brake pads from the rotating shaft;

[0021] When braking, the electromagnet is energized to generate an electromagnetic attraction force, which overcomes the elastic force of the spring assembly and presses the brake pads against the rotating shaft.

[0022] The brake pads have heat dissipation grooves on their surface, and a temperature alarm is installed inside the brake pads. When continuous braking causes the temperature to exceed the preset temperature, the power is automatically cut off for protection.

[0023] Optionally, the control module dynamically adjusts the PWM duty cycle and frequency output by the inverter according to the wind direction, phase deviation angle and torque compensation command, and feeds back the real-time drive frequency to the observer module to correct the rotor position observation model; wherein, the wind direction includes: downwind and headwind.

[0024] During the headwind start-up phase, the control module first applies a low-frequency, small-amplitude voltage vector and locks the rotor's initial position through the observer module. Then, based on the phase deviation angle, the q-axis current setpoint is dynamically corrected to ensure that the electromagnetic torque and aerodynamic torque are in the same direction. A progressive torque compensation strategy is then adopted to gradually increase the speed and suppress the influence of the back electromotive force on the system stability until the system leaves the headwind critical zone.

[0025] A control method for starting a sensorless EC wind turbine against wind, used to implement the control device for starting a sensorless EC wind turbine against wind as described above, the method comprising:

[0026] After the wind direction determination module is powered on and initialized, a pulse signal is injected to determine the wind direction.

[0027] The observer module monitors whether the fan speed exceeds the threshold.

[0028] The braking module is activated when the fan is detected to be reversing and the speed exceeds the threshold.

[0029] The observer module estimates the fan speed in real time;

[0030] When the detected rotational speed is below the safety threshold, the fan starts in the forward direction.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention proposes a control device for sensorless EC wind turbine start-up against wind, comprising: collecting wind turbine data using an observer module; detecting wind turbine speed using a speed detection module, and sending a braking signal when the speed exceeds a preset threshold; determining the initial rotation direction of the turbine using a wind direction judgment module, and sending a braking signal when the turbine is determined to be rotating in the opposite direction; receiving braking signals from the speed detection module and the wind direction judgment module using a braking module, and braking the turbine when both braking signals are received simultaneously; and receiving braking signals from the speed detection module and the wind direction judgment module using a control module, and correcting the observer module's frequency parameters via PWM drive. This implementation achieves reliable reverse rotation protection without increasing hardware costs, avoids the failure risk of physical sensors in dense building environments, and eliminates the risk of structural damage to equipment caused by passive reverse rotation and overspeed due to strong headwinds. Attached Figure Description

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a simplified diagram of a control device for starting an EC fan without a speed sensor against the wind, according to an embodiment of the present invention.

[0035] Figure 2 This is a simplified diagram of the reverse wind start-up braking module according to an embodiment of the present invention;

[0036] Figure 3 This is a diagram showing the signal transmission connection between the modules of the reverse wind start-up device according to an embodiment of the present invention;

[0037] Figure 4 This is a flowchart of the headwind start-up control method according to an embodiment of the present invention;

[0038] Figure 5 This is a system structure diagram of the observer module of the headwind start-up device according to an embodiment of the present invention;

[0039] The components include: 1. Observer module; 2. Rotation speed detection module; 3. Wind direction judgment module; 4. Control module; 5. Braking module; 5-1. Electromagnet; 5-2. Spring assembly; 5-3. Brake pad; 5-4. Heat dissipation groove; 6. Fan blade; 7. Fan shaft; 8. Motor; 9. Controller. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] This embodiment proposes a control device for starting an EC fan without a speed sensor against the wind, including:

[0043] Observer module 1 is used to collect wind turbine data, including wind turbine speed, angle, and back electromotive force.

[0044] The speed detection module 2 is used to detect the fan speed and send a braking signal when the speed exceeds the preset speed threshold.

[0045] Wind direction determination module 3 is used to determine the initial rotation of the wind turbine. When it is determined that the wind turbine is currently rotating in the opposite direction, a braking signal is sent.

[0046] Braking module 5 is used to receive braking signals from speed detection module 2 and wind direction judgment module 3. When braking signals are received from both modules at the same time, the fan is braked.

[0047] The control module 4 is used to receive signals from the speed detection module 2 and the wind direction judgment module 3, and to correct the observer module by dynamically adjusting the drive frequency.

[0048] like Figure 3 As shown in this embodiment, a control device for starting a wind turbine without a speed sensor against the wind includes: an observer module 1, a wind direction judgment module 2, a speed detection module 3, a braking module 5, and a control module 4.

[0049] The observer module 1 is connected to the speed detection module 2 and the control module 4. The observer module 1 predicts the wind turbine speed through the adaptive sliding mode observer model and transmits the predicted speed, angle and back electromotive force to the speed detection module 2.

[0050] The speed detection module 2 is connected to the observer module 1, the control module 4 and the braking module 5. It compares the estimated speed of the fan with the set speed threshold. When the speed exceeds the threshold, it sends a braking trigger signal to the braking module 5. It processes the signal transmitted by the observer module 1 and transmits the final speed value, speed error estimate and speed change rate to the control module 4.

[0051] The wind direction judgment module 3 is connected to the control module 4 and the braking module 5. The wind direction judgment module 3 determines the initial direction of the wind turbine by injecting high-frequency square wave pulses into the stator winding. When it is determined that the wind turbine is currently rotating in the opposite direction, a braking signal is sent to the braking module 5.

[0052] like Figure 2 As shown, the braking module 5 is fixed to the outer casing and brakes the fan when the braking conditions are met. The braking module 5 receives signals from the speed detection module 2 and the wind direction judgment module 3. When it simultaneously receives a fan reversal signal from the wind direction judgment module 3 and a speed exceeding the threshold signal from the speed detection module 2, the controller 9 of the braking module 5 is energized, causing the electromagnet 5-1 to generate magnetic force, which quickly presses the brake pad 5-3 against the fan shaft 7 for braking. The fan shaft 7 is connected to the fan blades 6. Figure 1 As shown.

[0053] Control module 4 is connected to wind direction judgment module 3, speed detection module 2, and observer module 1. Based on feedback results, it dynamically adjusts the control signal to improve the dynamic response of motor 8. Control module 4 receives signals from speed detection module 2 and wind direction judgment module 3, dynamically adjusts the PWM duty cycle and frequency of the inverter output, and feeds back the real-time drive frequency to observer module 1 to correct the rotor position observation model.

[0054] This embodiment achieves reliable reverse protection without increasing hardware costs, while eliminating the risk of structural damage to the equipment caused by passive reverse overspeed.

[0055] Furthermore, the observer module 1 employs an adaptive sliding mode observer, constructing a dynamic equation for the sliding surface based on the motor stator current and voltage signals. It ensures system stability by designing a Lyapunov function with the stator current error as the sliding surface, and uses an adaptive algorithm to dynamically adjust the observer switching gain online. Simultaneously, a saturation function is introduced to replace the sign function for smoothing and filtering the observer output. Combined with the PWM drive frequency parameters transmitted from the control module, it performs real-time, high-precision estimation of rotor speed and position information, and transmits the optimized estimation results to the speed detection module 2.

[0056] Furthermore, observer module 1 includes:

[0057] The back electromotive force observation unit is used to collect back electromotive force according to the current error equation.

[0058] The sliding surface unit is used to generate the sliding surface state through real-time integration of current error, and its output is used to control the gain of the observer module and the calculation of back electromotive force.

[0059] The parameter adaptive unit is used to automatically adjust the parameters of the observer module by setting stability conditions and parameter update laws using Lyapunov functions.

[0060] Specifically, in this embodiment, the observer module 1 includes: a back electromotive force observation unit, a sliding mode surface unit, and a parameter adaptive unit.

[0061] Back EMF observation unit: Constructing the current error equation: ,in This is the actual current. Observe the current;

[0062] Sliding surface elements include:

[0063] Sliding surface design: , ;

[0064] Sliding mode control law: using a saturation function Instead of symbolic functions, Boundary layer thickness;

[0065] Control input: , where K is the adaptive adjustment coefficient;

[0066] Equivalent control items: ;

[0067] Parameter adaptive unit: Lyapunov function designed as , , For adaptive rate coefficients;

[0068] Differentiating gives ;

[0069] Stability conditions: through design Ensure , The convergence parameter and ;

[0070] Parameter update law: , As a correction factor and .

[0071] The sliding surface defines the control objective of the system; the dynamic equation describes the process of the system moving toward the control objective; the sliding control law generates control inputs based on the dynamic equations to actively and robustly achieve the control objective; the control inputs are the signals that realize the control actions, including parts for driving and information extraction; the equivalent control term is the solution of the sliding surface dynamic equations under ideal sliding conditions, and the back electromotive force information can be obtained after filtering.

[0072] By employing the aforementioned observer module 1, traditional mechanical sensors are replaced, thus preventing external environmental issues from affecting the normal startup of the wind turbine. The system structure of the observer module 1 for the reverse wind start-up device is as follows: Figure 5 As shown.

[0073] Furthermore, the speed detection module 2 compares the speed estimate output by the observer module 1 with the preset reverse wind start safety threshold to detect whether there is an overspeed risk; when the fan speed is detected to exceed the threshold, it sends a torque compensation command to the control module 4 and a braking trigger signal to the braking module 5 at the same time.

[0074] Furthermore, the wind direction determination module 3 injects high-frequency square wave pulses with an amplitude less than 5% of the rated current into the stator windings, collects the three-phase current response signals, and decouples them into dq-axis components through coordinate transformation. Based on the phase characteristic difference of the d-axis current ripple amplitude, it determines the initial direction of rotation of the wind turbine. When reverse rotation is detected, it sends a braking trigger signal to the braking module 5. When the wind direction determination module 3 detects that the high-frequency response ripple amplitude of the d-axis current is significantly higher than the reference value during forward rotation, it determines that the wind turbine is rotating in reverse and takes braking measures.

[0075] Furthermore, the braking module 5 includes: an electromagnet 5-1, a spring assembly 5-2, and a brake pad 5-3; wherein, the brake pad 5-3 is located on both sides of the fan shaft 7, the electromagnet 5-1 is fixed on the side of the brake pad 5-3 away from the fan shaft 7, and one end of the spring assembly 5-2 is connected to the side of the brake pad 5-3 away from the fan shaft 7, and the other end is fixed to the outer housing.

[0076] When not braking, spring assembly 5-2 separates brake pad 5-3 from shaft 7;

[0077] During braking, the electromagnet 5-1 is energized to generate electromagnetic attraction, which overcomes the elastic force of the spring assembly 5-2 and presses the brake pad 5-3 against the rotating shaft 7.

[0078] The brake pad 5-3 has heat dissipation grooves 5-4 on its surface, and a temperature alarm is also installed inside the brake pad 5-3. When continuous braking causes the temperature to exceed the preset temperature, it will automatically cut off the power for protection.

[0079] When electromagnet 5-1 is energized, it generates an electromagnetic attraction force. Driven by electromagnetic attraction, the brake pads 5-3 on both sides overcome the elastic force of the spring group 5-2 and move synchronously toward the center of the rotating shaft 7. The brake pads 5-3 are in close contact with the surface of the rotating shaft 7, generating huge sliding friction and static friction at the moment of contact and during the continuous contact.

[0080] The electromagnetic attraction generated by electromagnet 5-1 during braking process This ensures that brake pads 5-3 apply a constant normal clamping force to the rotating shaft 7. The clamping force continuously generates braking torque between the brake pads 5-3 and the rotating shaft 7. Braking torque The force acts on the fan shaft 7 in the opposite direction to the rotation direction, rapidly consuming the kinetic energy of the shaft 7 and slowing it down until it is below the preset safety threshold.

[0081] Braking torque during braking This is determined by the frictional force generated between the brake pads 5-3 and the rotating shaft 7. The braking friction coefficient is... For the effective friction radius, The number of brake pads 5-3 that participate in generating friction. It must be greater than the driving torque that the fan shaft 7 may generate under the maximum backwind load, and a certain safety factor must be reserved.

[0082] During braking, electromagnet 5-1 needs to generate sufficient attraction to provide clamping force. And overcome the tension of spring assembly 5-2. The resulting electromagnetic attraction... ,in From the target braking torque By reverse deduction, This refers to the force exerted by spring assembly 5-2 when brake pad 5-3 is in the clamped position. This is the clamping force transmission efficiency coefficient.

[0083] Furthermore, the control module 4 dynamically adjusts the PWM duty cycle and frequency of the inverter output according to the wind direction, phase deviation angle, and torque compensation command, and feeds back the real-time drive frequency to the observer module 1 to correct the rotor position observation model. The wind direction includes: downwind and upwind. The rotor position observation model refers to the model of the adaptive sliding mode observer used by the observer module. The main corrections are made to the stator inductance Ls of the back EMF observation unit, the integral gain k of the sliding mode unit, and the adaptive coefficients of the parameter adaptive unit.

[0084] During the headwind start-up phase, control module 4 first applies a low-frequency, small-amplitude voltage vector and locks the rotor's initial position through observer module 1. Then, based on the phase deviation angle, it dynamically corrects the q-axis current setpoint to ensure that the electromagnetic torque and aerodynamic torque are in the same direction. It also adopts a progressive torque compensation strategy to gradually increase the speed and suppress the influence of back electromotive force on system stability until it leaves the headwind critical zone.

[0085] Specifically, control module 4 adopts a vector control strategy based on rotor field orientation to form a composite closed-loop control architecture. The core modules are the torque current component calculation unit and the observer module 1.

[0086] The outer loop of the composite closed-loop control architecture is the speed tracking control loop, with the input speed error... , This is a reference value for motor speed. The actual value of the motor speed is given; controller 9 is a PI regulator with anti-saturation compensation. ,in For proportional gain, The integral time constant is the anti-saturation gain. , for Q-axis current limit value, output q-axis current command .

[0087] The inner loop of the composite closed-loop control architecture is centered on controller 9. By estimating the motor status in real time and feeding it back to the outer loop control, sensorless high-precision control is achieved.

[0088] Furthermore, such as Figure 4 As shown, this embodiment also proposes a control method for starting an EC wind turbine against the wind without a speed sensor, including:

[0089] Step 1: After the wind direction determination module is powered on and initialized, a pulse signal is injected to determine the wind direction;

[0090] Step 2: The observer module monitors whether the fan speed exceeds the threshold.

[0091] Step 3: When the fan is detected to be reversing and the speed exceeds the threshold, the braking module is activated;

[0092] Step 4: The observer module estimates the wind turbine speed in real time;

[0093] Step 5: When the speed is detected to be lower than the safety threshold, the fan starts in the forward direction.

[0094] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A control device for starting an EC fan against the wind without a speed sensor, characterized in that, include: The observer module is used to collect wind turbine data; wherein, the wind turbine data includes: wind turbine speed, angle, and back electromotive force; The speed detection module is used to compare the fan speed with a preset speed threshold, and send a braking signal when the preset speed threshold is exceeded. The wind direction determination module is used to determine the initial rotation of the wind turbine. When it is determined that the wind turbine is currently rotating in the opposite direction, a braking signal is sent. The braking module, fixed on the outer housing, is used to receive braking signals from the speed detection module and the wind direction judgment module. When braking signals are received from both modules at the same time, the fan shaft is braked. The control module receives signals from the speed detection module and the wind direction judgment module, and corrects the observer module by dynamically adjusting the drive frequency.

2. The control device for starting an EC fan without speed sensor against wind as described in claim 1, characterized in that, The observer module employs an adaptive sliding mode observer, constructing a dynamic equation for the sliding surface based on the motor stator current and voltage signals. It ensures system stability by designing a Lyapunov function with the stator current error as the sliding surface and uses an adaptive algorithm to dynamically adjust the observer switching gain online. Simultaneously, a saturation function is introduced to replace the sign function for smoothing and filtering the observer output. Combined with the PWM drive frequency parameters transmitted from the control module, it performs real-time, high-precision estimation of rotor speed and position information, and transmits the optimized estimation results to the speed detection module.

3. The control device for starting an EC fan without speed sensor against wind as described in claim 1, characterized in that, The observer module includes: The back electromotive force observation unit is used to acquire the back electromotive force according to the current error equation; The sliding surface unit generates the sliding surface state through real-time integration of the current error, and its output is used to control the gain of the observer module and the calculation of the back electromotive force. The parameter adaptive unit, based on the sliding surface state, uses Lyapunov functions and dynamically adjusts the gain of the observer module by setting stability conditions and parameter update laws.

4. The control device for starting an EC fan without speed sensor against wind as described in claim 1, characterized in that, The wind direction determination module injects a high-frequency square wave pulse of preset amplitude into the stator winding, collects the three-phase current response signal, and decouples it into dq-axis components through coordinate transformation. Based on the phase characteristic difference of the d-axis current ripple amplitude, it determines the initial direction of the wind turbine. When a reverse rotation feature is detected, it sends a braking signal to the braking module.

5. The control device for starting an EC fan without speed sensor against wind according to claim 1, characterized in that, The braking module includes: an electromagnet, a spring assembly, and a brake pad; wherein, the brake pad is located on both sides of the fan shaft, the electromagnet is fixed on the side of the brake pad away from the fan shaft, one end of the spring assembly is connected to the side of the brake pad away from the fan shaft, and the other end is fixed to the outer housing. When not braking, the spring assembly separates the brake pads from the rotating shaft; When braking, the electromagnet is energized to generate an electromagnetic attraction force, which overcomes the elastic force of the spring assembly and presses the brake pads against the rotating shaft. The brake pads have heat dissipation grooves on their surface, and a temperature alarm is installed inside the brake pads. When continuous braking causes the temperature to exceed the preset temperature, the power is automatically cut off for protection.

6. The control device for starting an EC fan without speed sensor against wind as described in claim 1, characterized in that: The control module dynamically adjusts the PWM duty cycle and frequency output by the inverter according to the wind direction, phase deviation angle and torque compensation command, and feeds back the real-time drive frequency to the observer module to correct the rotor position observation model; wherein, the wind direction includes: downwind state and upwind state; During the headwind start-up phase, the control module first applies a low-frequency, small-amplitude voltage vector and locks the rotor's initial position through the observer module. Then, based on the phase deviation angle, the q-axis current setpoint is dynamically corrected to ensure that the electromagnetic torque and aerodynamic torque are in the same direction. A progressive torque compensation strategy is then adopted to gradually increase the speed and suppress the influence of the back electromotive force on the system stability until the system leaves the headwind critical zone.

7. A control method for starting a sensorless EC fan against wind, characterized in that, For implementing the control device for reverse wind start-up of a sensorless EC wind turbine as described in any one of claims 1-6, the method comprises: After the wind direction determination module is powered on and initialized, a pulse signal is injected to determine the wind direction. The observer module monitors whether the fan speed exceeds the threshold. The braking module is activated when the fan is detected to be reversing and the speed exceeds the threshold. The observer module estimates the fan speed in real time; When the detected rotational speed is below the safety threshold, the fan starts in the forward direction.

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