An ultra-high altitude wind turbine yaw electromagnetic braking system and method

Abstract

This invention discloses a yaw electromagnetic braking system and method for ultra-high altitude wind turbines, overcoming the problem of high cost associated with hydraulic braking methods when wind turbine nacelles slip during high winds. The system includes: a wind measurement device for assessing wind conditions during wind turbine operation and sending the assessment results to the main control system; a yaw system, including several yaw motors, for transmitting winding temperature signals back to a soft starter and the main control system PLC module; a yaw monitoring device for monitoring whether slippage occurs in the wind turbine and providing a basis for judgment to the main control system PLC module; the main control system PLC module for determining the current operating condition and deciding whether to perform electromagnetic braking; and a soft starter for receiving braking commands from the main control system, braking the yaw motors, and simultaneously monitoring the winding temperature of the yaw motors. This provides a low-cost solution to the problem of wind turbine nacelle slippage during high winds, improving power generation efficiency.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, and in particular to a yaw electromagnetic braking system and method for ultra-high altitude wind turbines. Background Technology

[0002] Wind power generation is a crucial component of the current development of new energy sources. Wind turbine generators are the main equipment for converting wind energy into electricity, and the yaw system within the unit plays a vital role in aligning with the wind. Inaccurate alignment will severely impact power generation efficiency; therefore, wind alignment accuracy has always been a key focus of research for wind turbine generators. Current wind turbine generators are becoming increasingly larger in capacity and longer in blades, resulting in smaller design margins. While the braking force of the yaw system may meet the needs under most operating conditions, it can lead to nacelle slippage in special wind conditions with strong turbulence. Slippage causes inaccurate alignment, severely reduces power generation efficiency, and results in lost revenue. It also accelerates the wear and tear on the yaw motor brake pads, leading to frequent yaw motor maintenance and turbine shutdowns—all detrimental to production.

[0003] The above problems can be solved by adding yaw motors and hydraulic clamps. More yaw motors and hydraulic clamps mean greater braking force, which can prevent the nacelle from sliding under conditions of excessive turbulence. For example, the Chinese Patent Office published an invention entitled "A Wind Turbine Yaw Control Method, Device, and Wind Turbine Unit" on August 23, 2019, with publication number CN110159483A. This invention's wind turbine yaw control method includes determining whether the wind turbine unit meets the yaw conditions; when the wind turbine unit meets the yaw conditions, controlling the release of the hydraulic brake; and within a first preset time after the release of the hydraulic brake, if the pressure of the hydraulic brake drops below a first preset yaw pressure, then activating the yaw drive unit. Using the control method of this embodiment, the yaw drive unit can be activated when the pressure of the hydraulic brake drops below the first preset yaw pressure. By setting a reasonable first preset yaw pressure, the problem of overloading the yaw drive unit when the hydraulic braking force is large can be improved; it can also improve the problem of the wind turbine drifting due to the yaw drive unit not opening for a long time after the braking force drops to a low level. However, the hydraulic braking method is more expensive. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem of slippage of the nacelle of wind turbine generator units during strong winds in the prior art, and the high cost of hydraulic braking. This invention provides a yaw electromagnetic braking system and method for ultra-high altitude wind turbine generator units, which solves the problem of slippage of the nacelle of wind turbine generator units during strong winds with a low-cost solution and improves power generation efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An electromagnetic braking system for yaw of an ultra-high altitude wind turbine includes:

[0007] Wind measurement equipment is used to assess wind conditions when the wind turbine is operating and send the assessment results to the main control system.

[0008] The yaw system is used to transmit the winding temperature signal back to the soft starter and the main control system PLC module, and includes several yaw motors;

[0009] Yaw monitoring device is used to monitor whether the wind turbine is slipping, and provides a basis for judgment for the main control system PLC module;

[0010] The main control system PLC module is used to determine the current operating condition and decide whether to perform electromagnetic braking.

[0011] The soft starter is used to receive braking commands from the main control system, brake the yaw motor, and monitor the winding temperature of the yaw motor.

[0012] High-altitude areas experience high wind speeds year-round. Furthermore, to ensure the insulation and withstand voltage of the power distribution system, a step-down design is implemented, using a main distribution voltage of 400VAC. In contrast, the main distribution voltage of traditional turbines is 690VAC. Therefore, this invention utilizes a soft starter, the rated voltage of which is 400VAC. Thus, applying this invention to wind turbines in high-altitude areas not only demonstrates strong technical relevance but also offers excellent cost-effectiveness. This invention monitors the speed of the cooling fan blades of the yaw motor using a yaw monitoring device, transmitting the data to the main control system PLC module. The PLC module determines when nacelle slippage occurs during generator operation and, based on the current operating status of the generator, issues a braking command to the soft starter for rapid braking. This keeps the nacelle in its original generator position, reducing the number of yaws and power generation losses. It features strong braking force, good effect, adaptability, and rapid response. Once the yaw motor reaches its rated torque, it effectively doubles the braking force, resulting in very strong braking capability. Furthermore, it offers high cost-effectiveness, as the selected components are not special products, are easy to procure, have low cost, and are easy to install without major modifications to the original generator design. Even existing generator sets can be easily upgraded using this invention to enhance wind resistance during high-wind power generation.

[0013] Preferably, the main control system includes a high-speed counting module for receiving signals from the wind measuring device and the yaw monitoring device. The wind speed signal measured by the wind measuring device is connected to the high-speed counting module of the main control system PLC. Since the return signal from the wind measuring device used in this invention is a frequency signal, it is connected to the high-speed counting module.

[0014] Preferably, the yaw monitoring device includes a capacitive proximity switch for monitoring the blade speed of the yaw motor cooling fan and determining the motor speed. To determine if the unit is slipping, it is necessary to monitor the yaw slip angle. Traditionally, an encoder can be used, but encoders are expensive. Therefore, this invention uses a capacitive proximity switch to monitor the blade speed of the yaw motor cooling fan. Since the fan blades and motor bearings are integrated, the blade speed is the motor speed. Thus, the faster the nacelle slips, the greater the thrust of the turbulent wind, and the higher the rotor speed of the yaw motor, the greater the induced rotor flux, and the greater the braking force. Therefore, DC braking has a certain degree of adaptability when used in wind turbine braking. The relationship between the nacelle slip angular velocity and the motor speed is as follows:

[0015] The yaw motor blade speed is calculated as follows: nacelle angular velocity × number of yaw bearing teeth ÷ number of yaw drive teeth × yaw drive transmission ratio ÷ 360° × number of yaw motor blades; the unit of the yaw motor blade speed is Hertz.

[0016] Preferably, two capacitive proximity switches are installed on the same circumference with the yaw motor shaft center as the center point. The distance between the two capacitive proximity switches is half the distance between the measuring points on the yaw motor blades. To prevent repeated activation of the capacitive proximity switches due to vibration or other unexpected reasons, which could lead to the PLC module misinterpreting it as nacelle slippage and activating the electromagnetic brake, this invention installs two capacitive proximity switches on the same motor. When the two capacitive proximity switches measure similar motor speeds, it is considered that nacelle slippage has occurred.

[0017] Preferably, the wind measuring device includes:

[0018] An anemometer is used to measure wind speed, determine whether turbulent weather is present, and transmit the measured wind speed signal to the main control system PLC module. The anemometer used in this invention returns a frequency signal.

[0019] Preferably, the yaw motor is equipped with a thermistor, which is used to collect the temperature data of the yaw motor windings. The thermistor is preferably a PT100 or PTC, and the PT100 or PTC temperature signal of the yaw motor is connected to the soft starter and the main control system PLC module, respectively. In a wind turbine generator set, there are several or more yaw motors. The temperature signal of one yaw motor can be connected to the soft starter, and the temperature signals of the remaining yaw motors can be connected to the thermistor module of the main control system to monitor the temperature of the yaw motor stator windings.

[0020] A method for yaw electromagnetic braking of ultra-high altitude wind turbines includes the following steps:

[0021] S1: Determine whether it is necessary to connect to the electromagnetic braking system. If yes, proceed to step S2. If not, re-determine.

[0022] S2: Connect the soft starter to the yaw motor power distribution circuit;

[0023] S3: Determine whether to perform electromagnetic braking. If yes, proceed to step S4; otherwise, re-determine.

[0024] S4: The soft starter brakes the yaw motor and monitors the temperature of the yaw motor windings.

[0025] During braking, the kinetic energy of external components is converted into heat energy in the motor windings. Excessive braking current and excessive braking time may cause the motor windings to overheat severely or even burn out. To prevent unnecessary damage to the motor, it is necessary to monitor the temperature of the yaw motor windings.

[0026] Preferably, in step S1, the condition for determining whether it is necessary to connect to the electromagnetic braking system is:

[0027] S1.1: Determine whether the wind turbine is in normal grid-connected power generation state. If yes, proceed to step S1.2. If not, disconnect the soft starter from the yaw motor power distribution circuit and re-determine.

[0028] S1.2: Determine whether the average wind speed is greater than the preset value. If yes, proceed to step S1.3. If not, disconnect the soft starter from the yaw motor power distribution circuit and return to step S1.1.

[0029] S1.3: Determine whether the wind turbine is in a non-active yaw state. If yes, proceed to step S2. If not, disconnect the soft starter from the yaw motor power distribution circuit and return to step S1.1.

[0030] Specifically, there are three conditions for determining whether to execute electromagnetic braking: 1. The unit is in normal grid-connected power generation; 2. The average wind speed is greater than the preset value; 3. The unit is not in active yaw mode. When the above three conditions are met, the soft starter used for electromagnetic braking is connected to the yaw motor power distribution circuit. When 1 and 2 are not met, it is not necessary to connect to the electromagnetic braking system, because this function is not required, and the yaw motor brake pads and hydraulic clamps can fully meet the braking requirements; when 3 is not met, the electromagnetic braking function cannot be used. Active yaw and electromagnetic braking are completely opposite functions, so the software and hardware design should include interlock protection. At the same time, these three conditions have the highest interruption level in this function. When any condition is not met, the soft starter should be disconnected from the yaw motor power distribution circuit.

[0031] Preferably, in step S3, the condition for determining whether to perform electromagnetic braking is:

[0032] S3.1: Determine if the yaw motor winding temperature is within acceptable limits. If yes, proceed to step S3.2; otherwise, re-determine.

[0033] S3.2: Determine whether the speed measured by the capacitor proximity switch is overspeeding. If so, apply electromagnetic braking. If not, return to step S3.1.

[0034] Electromagnetic braking will only be performed when the yaw motor winding temperature is normal and the speed measured by the capacitor proximity switch is normal.

[0035] Preferably, step S4 further includes: when performing electromagnetic braking, if the yaw motor winding temperature exceeds a preset value or the braking time reaches a preset value, the electromagnetic braking is immediately disengaged. Excessive braking current and excessively long braking time may cause the motor windings to overheat severely or even burn out. To prevent the yaw motor from overheating and causing unnecessary damage, it is necessary to preset braking time thresholds and winding temperature thresholds.

[0036] Therefore, the present invention has the following beneficial effects:

[0037] 1. Compared with existing yaw braking systems, the cost of this invention is only a fraction of that of existing systems, resulting in a significant cost reduction; 2. The faster the nacelle slides, the greater the torque generated during braking, enabling rapid and powerful braking with remarkable effectiveness; 3. The components are easy to install, requiring no major modifications to the original aircraft design, exhibiting high adaptability and rapid response. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the architecture of the yaw electromagnetic braking system in this invention;

[0039] Figure 2 This is a schematic diagram of the installation of the capacitor proximity switch in the yaw electromagnetic braking system of the present invention;

[0040] Figure 3 This is a schematic diagram of the yaw motor power distribution circuit of the yaw electromagnetic braking system in this invention;

[0041] Figure 4 This is a schematic diagram of the control loop of the yaw electromagnetic braking system in this invention;

[0042] Figure 5 This is a flowchart of the yaw electromagnetic braking method in this invention.

[0043] In the diagram: 1. Anemometer; 2. Main control system PLC module; 3. Soft starter; 4. Yaw monitoring device; 5. Yaw motor; 6. First proximity switch; 7. Second proximity switch; 8. Fan blade. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0045] Example 1:

[0046] This embodiment describes a yaw electromagnetic braking system for ultra-high altitude wind turbines, such as... Figure 1 As shown, it includes: a wind gauge 1, a main control system PLC module 2, a yaw monitoring device 4, a soft starter 3, and a yaw motor 5. The main control system PLC module includes a high-speed counting module and a thermistor module. The yaw motor also includes a thermistor. The yaw monitoring device includes a capacitive proximity switch. In this embodiment, the thermistor is PT100 or PTC.

[0047] The anemometer is mainly used to measure wind speed and can also determine whether turbulent weather is present. It transmits the measured wind speed signal to the main control system PLC module. Because the anemometer's return signal is a frequency signal, it is connected to the high-speed counting module of the main control system PLC module. The main control system PLC module is the data processing center used to determine the current operating condition and decide whether to activate electromagnetic braking. The PT100 or PTC temperature signal of the yaw motor is connected to the soft starter and the main control system module, respectively. In a wind turbine generator set, there are several yaw motors; the temperature signal of one yaw motor can be connected to the soft starter. The temperature signals of the remaining yaw motors are connected to the RTD module of the main control system to monitor the temperature of the yaw motor stator windings; the capacitive proximity switch is used to measure the speed of the yaw motor, providing necessary judgment data to the PLC of the main control system; the soft starter is the actuator for implementing DC braking, and its control input interface is connected to the control output interface of the main control system, receiving commands from the PLC module of the main control system and braking the yaw motor, while monitoring the winding temperature of the yaw motor; the yaw motor is the monitored and controlled object, and it also sends back temperature signals to the soft starter and the PLC module of the main control system.

[0048] Specifically, to determine whether the unit is slipping, it is necessary to monitor the yaw slip angle. Traditionally, encoders can be used, but they are expensive. Therefore, this invention uses a capacitive proximity switch to monitor the blade speed of the yaw motor cooling fan. Since the fan blades and motor bearings are integrated, the fan blade speed is the motor speed. Thus, the faster the nacelle slips, the greater the thrust of the turbulent airflow. Simultaneously, the higher the rotor speed of the yaw motor, the greater the induced rotor flux, and the greater the braking force. Therefore, DC braking in wind turbine braking has a certain degree of adaptability. The relationship between the nacelle slip angular velocity and the motor speed is as follows:

[0049] The yaw motor blade speed is calculated as follows: nacelle angular velocity × number of yaw bearing teeth ÷ number of yaw drive teeth × yaw drive transmission ratio ÷ 360° × number of yaw motor blades; the unit of the yaw motor blade speed is Hertz.

[0050] Assuming the nacelle angular velocity is 0.25° / s, the yaw bearing has 180 teeth, the yaw actuator has 16 teeth, the yaw actuator gear ratio is 2933.4, and the yaw motor has 5 blades, then the yaw motor speed is 114.58 Hz, equivalent to 1375 rpm. This shows that even a small nacelle sliding speed will result in a relatively high yaw motor speed. Therefore, the applied braking current does not need to be too high; the specific amount can be determined through on-site testing. The preferred initial setting for the soft starter braking current is 10-20% of the rated current.

[0051] The basic principle used in this invention is DC braking. According to the principles of motor theory, the electromagnetic torque of a motor is: τ=kBr×Bs;

[0052] Where τ is the electromagnetic torque, Bs is the stator flux, and Br is the rotor flux. If a direct current is applied to the stator, it can be seen that the higher the applied voltage, the greater the current and the greater the stator flux. The flux on the rotor is the induced flux. Therefore, the higher the rotor speed, the stronger the induced flux, and the greater the electromagnetic torque and braking force.

[0053] However, during braking, the kinetic energy of external components will be converted into heat energy of the yaw motor windings. Excessive braking current and excessive braking time may cause the yaw motor windings to overheat severely or even burn out. To prevent unnecessary damage to the yaw motor, it is necessary to control the setting of braking current and braking time.

[0054] To protect the yaw motor, the thermistors PT100 or PTC used to monitor the temperature of the yaw motor windings need to be connected to the main control system PLC control module and soft starter for monitoring. Once the winding temperature exceeds the limit, braking must be stopped.

[0055] This invention monitors the speed of the cooling fan blades of the yaw motor using a capacitive proximity switch, transmitting the data to the main control system PLC. The PLC determines that nacelle slippage has occurred during generator operation and, based on the current operating status of the generator, issues a braking command to the soft starter for rapid braking. This keeps the nacelle in its original generator position, reducing the number of yaws and power generation losses. It features strong braking force, good effect, adaptability, and rapid response. Once the yaw motor reaches its rated torque, it is equivalent to doubling the braking force, resulting in very strong braking capability. It also offers high cost-effectiveness, as the selected components are not special products, are easy to procure, and are simple to install without major modifications to the original generator design. Even existing generator sets can be easily upgraded using this invention to enhance their wind resistance during high-wind power generation.

[0056] The capacitive proximity switch is installed on the housing of the yaw motor to detect the rotational speed of the yaw motor rotor. The signal measured by the capacitive proximity switch is connected to the high-speed counting module of the main control system PLC.

[0057] To prevent repeated activation of the capacitive proximity switch due to vibration or other unexpected causes, which could lead to the PLC misinterpreting it as engine compartment slippage and activating the electromagnetic brake, this embodiment installs two capacitive proximity switches on the same motor. Figure 2 As shown, two capacitive proximity switches are installed on the same circumference with the yaw motor shaft as the center point, and the distance between them is half the distance between the measuring points of the yaw motor blades 8. When the two capacitive proximity switches measure similar motor speeds, it is considered that the nacelle has slipped. Furthermore, the two capacitive proximity switches must be installed staggered. When the first proximity switch 6 detects the yaw motor blades, the second proximity switch 7 should be positioned between the two blades to ensure that the states of the two capacitive proximity switches cannot be simultaneously set to 1. The main purpose is to prevent the capacitive proximity switches from repeatedly being set to 1 due to slight vibrations caused by a blade being extremely close to the switch, thus mistakenly interpreting the nacelle as slipping and activating the electromagnetic braking function. Only when the speeds measured by the two capacitive proximity switches are extremely close and exceed the preset overspeed value can it be considered that the nacelle has slipped.

[0058] like Figure 3As shown, in this embodiment, the yaw motor power distribution circuit of the yaw electromagnetic braking system includes circuit breakers Q01, Q02, Q03, Q04, Q05, and Q06, contactors KM01, KM02, and KM03, and yaw motors M1, M2, M3, and M4. Circuit breakers Q01, Q02, Q03, Q04, and Q05, contactors KM01 and KM02, and yaw motors M1, M2, M3, and M4 belong to the yaw system. First, the 400VAC power supply busbars L1, L2, and L3 are connected to terminals 1, 3, and 5 of the yaw main circuit breaker Q01, respectively. Terminals 2, 4, and 6 of circuit breaker Q01 are connected to terminals 1, 3, and 5 of contactor KM01 and terminals 5, 3, and 1 of contactor KM02, respectively. When connecting to contactor KM02, phase reversal was performed because the yaw motor needs to rotate in both directions. After connecting terminals 2, 4, and 6 of contactors KM01, KM02, and KM03 in parallel, they are connected together to the incoming terminals 1, 3, and 5 of circuit breakers Q02, Q03, Q04, and Q05. The outgoing terminals 2, 4, and 6 of circuit breakers Q02, Q03, Q04, and Q05 are connected to the power supply terminals U1, V1, and W1 of yaw motors M1, M2, M3, and M4, respectively. The incoming terminals 1, 3, and 5 of contactor KM03 are connected to the outgoing terminals 2T1, 4T2, and 6T3 of the soft starter. The power supply terminals 1L1, 3L2, and 5L3 of the soft starter are connected to the outgoing terminals 2, 4, and 6 of circuit breaker Q06. The incoming terminals 1, 3, and 5 of circuit breaker Q06 are connected to the 400VAC power supply bus L1, L2, and L3 respectively. The working power supply used by the soft starter is 230VAC. Power supply terminal 1 is connected to terminal 6 of circuit breaker Q06, and power supply terminal 2 is connected to bus N.

[0059] To generate electricity more effectively, wind turbines need to be aligned with the wind direction frequently. The system that performs this alignment is the yaw system. In this embodiment, the yaw system has four motors to drive the wind turbine's body to rotate left and right. When contactor KM01 is engaged, the motor rotates to the right (clockwise when viewed from the rear of the motor). When contactor KM02 is engaged, the motor rotates to the left. The wiring sequence of phases A and C of contactor KM02 was adjusted during wiring, allowing the motor to rotate in both directions, thus achieving left and right yaw. Because yaw and braking are opposite actions, an interlock design was implemented in the hardware to ensure that when contactor KM01 or KM02 is engaged, contactor KM03 is not engaged, and vice versa. Once the wind turbine is aligned with the wind direction, it needs to remain stationary. During this time, contactors KM01 and KM02 must remain disconnected. Under these conditions, the PLC module can issue a command to engage contactor KM03, connecting the soft starter to the yaw motor power distribution circuit. At the same time, due to the hardware interlock design, contactors KM01 and KM02 cannot engage, ensuring the safety of the power distribution line.

[0060] like Figure 4As shown, in this embodiment, in the control circuit of the yaw electromagnetic braking system, the temperature input terminals 25, 26, and 27 of the soft starter are connected to the PT100 temperature sensor of the yaw motor M1, and the start command receiving terminal 13, stop command receiving terminal 14, and brake command receiving terminal 15 (which needs to be set to receive control commands using this terminal when setting the soft starter parameters) are respectively connected to the digital output terminals DO1, DO2, and DO3 of the main control system PLC module. The control circuit connected to the soft starter needs to be interlocked with the yaw system control circuit. Therefore, the digital output terminal DO4 of the main control system PLC module is connected to the auxiliary terminal 11 of contactor KM03, the auxiliary terminal 12 of contactor KM03 is connected to the control coil terminal A1 of contactor KM01, the digital output terminal DO5 is connected to the auxiliary terminal 21 of contactor KM03, the auxiliary terminal 22 of contactor KM03 is connected to the control coil terminal A1 of contactor KM02, the digital output terminal DO6 is connected to the auxiliary terminal 11 of contactor KM01, the auxiliary terminal 12 of contactor KM01 is connected to the auxiliary terminal 11 of contactor KM02, the auxiliary terminal 12 of contactor KM02 is connected to the control coil terminal A1 of contactor KM03, and finally, the control coil terminals A2 of the three contactors KM01, KM02, and KM03 are connected together to the GND terminal of the main control system PLC module. The speed signals returned by capacitive proximity switches S01 and S02 are connected to the high-speed counting channels GS01 and GS02 terminals. The capacitive proximity switches are powered by 24VDC, which can be connected to the 24VDC power interface provided by the main control system PLC module. The frequency signal returned by the anemometer is connected to the high-speed counting channel GS03 of the PLC module. The PT100 temperature sensors of the yaw motors M2, M3, and M4 are connected to the AI ​​input channel terminals 1, 2, 3, 4, 5, 6, 7, 8, and 9 of the PLC module, respectively.

[0061] After the soft starter is connected, Figure 4 The motor speeds 01 and 02, measured by capacitive proximity switches, provide the main control system PLC module with motor speed data for judgment. Motor temperatures M01, M02, M03, and M04 are the winding temperature sensors inside the four yaw motors, providing motor temperature information to the main control system PLC module for determining if the motors are overheating. When the wind turbine's fuselage experiences unwanted slippage due to excessive air turbulence—that is, when the fuselage undergoes unexpected involuntary yaw, deviating from its original windward direction—the motor speed measured by the capacitive proximity switches will rapidly increase. Simultaneously, if the program determines that other conditions meet the braking requirements, the main control PLC issues commands through DO1 and DO3. Upon receiving the command, the soft starter outputs a DC current of appropriate intensity according to preset parameter values ​​to brake, preventing unexpected slippage and maintaining the fuselage's alignment with the wind.

[0062] When the wind direction changes and the unit needs to realign with the wind, contactor KM03 must be turned off, i.e., the electromagnetic brake must be disengaged. Only then can contactor KM01 or contactor KM02 be engaged to allow the wind turbine to yaw left or right and actively realign with the wind.

[0063] Example 2:

[0064] This embodiment describes a yaw electromagnetic braking method for ultra-high altitude wind turbines, such as... Figure 5 As shown, the process includes the following steps: After the main control system PLC module is working normally:

[0065] Step 1: Determine the current status of the unit.

[0066] If the unit is in a normal grid-connected power generation state, proceed to the second step. If it is not in a grid-connected power generation state, set the digital output terminal DO6 to zero, that is, disconnect the contactor KM03, and the electromagnetic braking system exits the electrical circuit. In other words, disconnect the soft starter from the yaw motor power distribution circuit and re-evaluate.

[0067] Step 2: Determine if the current wind speed is within the preset range and if it is turbulent weather. If the conditions are met, proceed to Step 3. If not, the electromagnetic braking system exits the electrical circuit, that is, the soft starter is disconnected from the yaw motor power distribution circuit, and the process returns to Step 1 to start the judgment again.

[0068] Step 3: After the wind speed meets the conditions, determine whether the unit is in a non-yaw state. If it does not actively yaw, set the digital output terminal DO6 to 1, that is, make the contactor KM03 energize and connect the electromagnetic braking system to the electrical circuit. If not, the electromagnetic braking system is disconnected from the electrical circuit, that is, the soft starter is disconnected from the yaw motor power distribution circuit, and return to step 1 to start the judgment again.

[0069] The three judgment processes in steps one, two, and three have the highest interruption level. If any one of these three conditions is not met at any time, the electromagnetic braking system should be immediately disconnected from the electrical circuit. After the electromagnetic braking system is connected to the electrical circuit, i.e., after the soft starter is connected to the yaw motor power distribution circuit, the main control system PLC module continues to make judgments.

[0070] Step 4: Determine if the yaw motor winding temperature is normal. If it is normal, proceed to step 5. If not, and the three conditions mentioned in steps 1, 2, and 3 are still met, continue monitoring the yaw motor temperature until it returns to normal.

[0071] Step 5: Determine the speed of the capacitor proximity switches. If the speeds of the two capacitor proximity switches are close and both exceed the preset value, the output channels DO1 and DO3 of the main control system PLC module will output simultaneously, and the soft starter will brake. After the preset time is reached, the braking is completed, DO1 and DO3 stop outputting, and DO2 outputs to notify the soft starter to stop. The braking process is complete. If the speed does not reach the preset value, the yaw motor winding temperature and the speed returned by the capacitor proximity switches will be continuously monitored.

[0072] Compared with existing yaw braking systems, the cost of the technical solution of this invention is only a fraction of that of existing systems, resulting in a significant cost reduction. Furthermore, the faster the cabin slides, the greater the torque generated during braking, enabling rapid and powerful braking with remarkable effectiveness.

[0073] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications may be made without departing from the technical solutions described in the claims.

Claims

1. A yaw electromagnetic braking system for ultra-high altitude wind turbines, characterized in that, include: Wind measurement equipment is used to assess wind conditions when the wind turbine is operating and send the assessment results to the main control system PLC module. The yaw system is used to simultaneously transmit winding temperature signals to the soft starter and the main control system PLC module. It includes several yaw motors. The temperature signal of one yaw motor is connected to the soft starter, and the temperature signals of the other yaw motors are connected to the thermal resistance module of the main control system. The yaw monitoring device includes two capacitive proximity switches, which are installed in a staggered manner. When one of the capacitive proximity switches detects the yaw motor blades, the other capacitive proximity switch is positioned in the middle of the two blades. This device is used to monitor whether the wind turbine is slipping and provides a basis for judgment for the main control system PLC module. The main control system PLC module is used to determine the current operating condition and decide whether to perform electromagnetic braking. The soft starter is used to receive braking commands from the main control system, output DC current of corresponding intensity according to preset parameter values, brake the yaw motor, and monitor the winding temperature of the yaw motor at the same time. The control loop connected to the soft starter is interlocked with the yaw system control loop.

2. The yaw electromagnetic braking system for ultra-high altitude wind turbines according to claim 1, characterized in that, The main control system includes a high-speed counting module for receiving signals from the wind measurement equipment and the yaw monitoring device.

3. A yaw electromagnetic braking system for ultra-high altitude wind turbines according to claim 1 or 2, characterized in that, The yaw monitoring device includes a capacitive proximity switch, used to monitor the speed of the yaw motor cooling fan blades and determine the motor speed.

4. The yaw electromagnetic braking system for ultra-high altitude wind turbines according to claim 3, characterized in that, There are two capacitive proximity switches, which are installed on the same circumference with the yaw motor shaft as the center. The distance between the two capacitive proximity switches is half the distance between the measuring points of the yaw motor blades being measured.

5. A yaw electromagnetic braking system for ultra-high altitude wind turbines according to claim 1 or 2, characterized in that, The aforementioned wind measurement equipment includes: An anemometer is used to measure wind speed, determine the current weather, and transmit the measured wind speed signal to the main control system PLC module.

6. A yaw electromagnetic braking system for ultra-high altitude wind turbines according to claim 1 or 2, characterized in that, The yaw motor is equipped with a thermistor, which is used to collect the temperature data of the yaw motor windings.

7. A yaw electromagnetic braking method for ultra-high altitude wind turbines, applied to the yaw electromagnetic braking system for ultra-high altitude wind turbines as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Determine whether it is necessary to connect to the electromagnetic braking system. If yes, proceed to step S2. If not, re-determine. S2: Connect the soft starter to the yaw motor power distribution circuit; S3: Determine whether to perform electromagnetic braking. If yes, proceed to step S4; otherwise, re-determine. S4: The soft starter brakes the yaw motor and monitors the temperature of the yaw motor windings.

8. The yaw electromagnetic braking method for ultra-high altitude wind turbines according to claim 7, characterized in that, In step S1, the condition for determining whether it is necessary to connect to the electromagnetic braking system is: S1.1: Determine whether the wind turbine is in normal grid-connected power generation state. If yes, proceed to step S1.

2. If not, disconnect the soft starter from the yaw motor power distribution circuit and re-determine. S1.2: Determine whether the average wind speed is greater than the preset value. If yes, proceed to step S1.

3. If not, disconnect the soft starter from the yaw motor power distribution circuit and return to step S1.

1. S1.3: Determine whether the wind turbine is in a non-active yaw state. If yes, proceed to step S2. If not, disconnect the soft starter from the yaw motor power distribution circuit and return to step S1.

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9. A method for yaw electromagnetic braking of an ultra-high altitude wind turbine according to claim 7 or 8, characterized in that, In step S3, the condition for determining whether to perform electromagnetic braking is as follows: S3.1: Determine if the temperature of the yaw motor winding is normal. If yes, proceed to step S3.

2. If not, re-determine. S3.2: Determine whether the speed measured by the capacitor proximity switch is overspeeding. If so, apply electromagnetic braking. If not, return to step S3.

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10. A method for yaw electromagnetic braking of an ultra-high altitude wind turbine according to claim 7, characterized in that, Step S4 further includes: when performing electromagnetic braking, if the temperature of the yaw motor winding exceeds a preset value or the braking time reaches a preset value, the electromagnetic braking is immediately disengaged.

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