Variable pitch control system, method and equipment

Abstract

The invention provides a variable pitch control system, method and equipment, and belongs to the technical field of wind power generation. The system comprises a power grid system, a fan master control system, three variable pitch control cabinets and a back-up power source, the power grid system is electrically connected with the fan master control system, the fan master control system is in communication and electrical connection with the first variable pitch control cabinet, the three variable pitch control cabinets are in communication and electrical connection, and the back-up power source is electrically connected with the three variable pitch control cabinets. And each variable pitch control cabinet is connected with a variable pitch motor. And when a fault occurs, a backup power supply supplies power. The fan master control sends a blade angle regulation and control instruction, and the three variable-pitch control cabinets control the variable-pitch motor according to the instruction to adjust the corresponding blade angle. Reliability is guaranteed through redundant power supply, accurate and efficient adjustment of the paddle angle is achieved through hierarchical regulation and control, meanwhile, the stability and coordination of the system are improved through communication cooperation, and therefore the power generation efficiency is improved, and shutdown loss is reduced.

Description

Technical Field

[0001] The present invention relates to the field of wind power generation, and in particular to a variable pitch control system, a control method of the variable pitch control system and an electronic device. Background Art

[0002] In today's world, energy demand is increasing day by day, while traditional fossil energy reserves are decreasing day by day, and the shadow of energy crisis is gradually covering the world. At the same time, the environmental pollution problems caused by the extensive use of fossil energy, such as greenhouse gas emissions and acid rain, have caused considerable damage to the ecological environment and seriously threatened the sustainable development of mankind. Against this background, finding clean and sustainable energy has become a major issue faced by countries around the world. Wind power generation, as an inexhaustible and clean energy, has become an important choice for coping with energy crises and environmental challenges due to its outstanding advantages such as renewable and pollution-free. However, with the rapid development of the wind power industry, wind turbines face many difficulties in operation. Especially in the complex and changeable natural environment, ensuring the stable operation of wind turbines and maintaining reliable power generation efficiency has become a key issue that needs to be solved urgently.

[0003] At present, the variable pitch control system plays a vital role as the core component of wind turbines. It is like the "smart brain" of wind turbines. It can accurately control the speed and power output of the unit by precisely changing the pitch angle of the blades. When the wind speed is low, the system can adjust the pitch angle so that the blades can capture as much wind energy as possible, thereby improving the power generation efficiency; when the wind speed is too high, the pitch angle can be adjusted in time to avoid damage to the unit due to overload, ensuring the safe and stable operation of the unit. In recent years, the domestic wind power industry has developed rapidly, and the technical level has been continuously improved. The mainstream units have successfully moved from the 3.XMW platform to the 6.XMW platform. This leap reflects my country's remarkable achievements in wind power technology innovation and also provides strong technical support for solving energy problems.

[0004] However, with the continuous upgrading of the power level of the unit, the existing variable pitch control system is unable to control the wind turbine to improve the power generation efficiency and maintain the stability of power generation under variable wind speed, wind direction and different geographical and climatic conditions. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a pitch control system, method and device to solve the above problems.

[0006] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a pitch control system, including: a power grid system, a wind turbine main control system, a first pitch control cabinet, a second pitch control cabinet, a third pitch control cabinet and a backup power supply, the power grid system is electrically connected to the wind turbine main control system, the wind turbine main control system is respectively communicated and electrically connected to the first pitch control cabinet, the first pitch control cabinet is respectively communicated and electrically connected to the second pitch control cabinet, the first pitch control cabinet is also electrically connected to the third pitch control cabinet, the second pitch control cabinet is also communicated and electrically connected to the third pitch control cabinet, the backup power supply is respectively electrically connected to the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet, and the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet are all electrically connected to the pitch motor; A power grid system, used to supply power to the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet; A backup power supply is used to supply power to the first variable pitch control cabinet, the second variable pitch control cabinet and the third variable pitch control cabinet when the power grid system fails; The wind turbine main control system is used to send the first blade angle control instruction, the second blade angle control instruction and the third blade angle control instruction to the first variable pitch control cabinet, the second variable pitch control cabinet and the third variable pitch control cabinet respectively; The first variable pitch control cabinet is used to control the corresponding variable pitch motor to perform corresponding actions according to the first blade angle control instruction to adjust the angle of the corresponding blade; The second variable pitch control cabinet is used to control the corresponding variable pitch motor to perform corresponding actions according to the second blade angle control instruction to adjust the angle of the corresponding blade; The third pitch control cabinet is used to control the corresponding pitch motor to perform corresponding actions according to the third blade angle control instruction to adjust the angle of the corresponding blade.

[0007] Optionally, the pitch control system further includes: a braking resistor, a limit switch and a proximity switch; A braking circuit is provided in the pitch control cabinet, the braking resistor is electrically connected to the braking circuit, the signal output end of the limit switch and the signal output end of the proximity switch are electrically connected to the signal input end of the pitch control cabinet respectively, the limit switch is set at the extreme position of the blade, and the proximity switch is set at the warning position of the blade; The external braking resistor is used to discharge the feedback energy generated when the pitch motor is in the braking state; The limit switch is used to send a signal to the pitch control cabinet to stop the pitch motor when the blade reaches the limit position of the blade; The proximity switch is used to send a blade angle calibration signal to the pitch control cabinet when the blade reaches the preset position; The pitch control cabinet is also used to control the pitch motor to stop running according to the pitch motor stop running signal; The pitch control cabinet is also used to check the signal according to the blade angle and control the pitch motor to decelerate.

[0008] Optionally, the energy storage capacity of the backup power supply is calculated as follows: Obtaining normal operating energy and fault operating energy of blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet; Calculate the sum of the normal operating energies of the blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet to obtain the total normal operating energy of the blades; Calculate the sum of the fault operation energies of the blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet to obtain the total fault operation energy of the blades; The sum of the total energy of the blade's normal operation and the total energy of the blade's fault operation is calculated, and the product of the sum and the preset safety factor is calculated to obtain the blade's guaranteed feathering energy; Based on the blade feathering energy and the voltage range in which the backup power supply can operate, the energy storage capacity of the backup power supply is obtained.

[0009] Optionally, the pitch control system further includes: a first safety position relay, a second safety position relay, a third safety position relay, a first EFC relay, a second EFC relay and a third EFC relay; The first output end of the first pitch control cabinet is connected to the first end of the coil of the first safety position relay, the second end of the coil of the first safety position relay is connected to the first negative terminal of the first pitch control cabinet, the second output end of the first pitch control cabinet is connected to the first end of the first normally open contact of the first safety position relay, the first end of the first normally open contact of the first safety position relay is connected to the second end of the first normally open contact of the first safety position relay, the second end of the first normally open contact of the first safety position relay is connected to the first end of the first normally open contact of the second safety position relay, the first end of the first normally open contact of the second safety position relay is connected to the second end of the first normally open contact of the second safety position relay, the second end of the first normally open contact of the second safety position relay is connected to the first end of the first normally open contact of the third safety position relay, the first end of the first normally open contact of the third safety position relay is connected to the second end of the first normally open contact of the third safety position relay, and the The second end of the first normally open contact of the position relay is respectively connected to the first end of the coil of the first EFC relay, the first end of the coil of the second EFC relay, and the first end of the coil of the third EFC relay, the second negative terminal of the first pitch control cabinet is respectively connected to the second end of the coil of the first EFC relay, the second end of the coil of the second EFC relay, and the second end of the coil of the third EFC relay, the third negative terminal of the first pitch control cabinet is connected to the first negative terminal of the second pitch control cabinet, the first output terminal of the second pitch control cabinet is connected to the first end of the coil of the second safety position relay, the second end of the coil of the second safety position relay is connected to the second negative terminal of the second pitch control cabinet, the third negative terminal of the second pitch control cabinet is connected to the first negative terminal of the third pitch control cabinet, the first output terminal of the third pitch control cabinet is connected to the first end of the coil of the third safety position relay, and the second end of the coil of the third safety position relay is connected to the second negative terminal of the third pitch control cabinet.

[0010] Optionally, the first input end of the first pitch control cabinet is connected to the first end of the normally open contact of the first EFC relay, the first end of the normally open contact of the first EFC relay is connected to the second end of the normally open contact of the first EFC relay, and the second end of the normally open contact of the first EFC relay is connected to the first positive terminal of the first pitch control cabinet, the first input end of the second pitch control cabinet is connected to the first end of the normally open contact of the second EFC relay, the first end of the normally open contact of the second EFC relay is connected to the second end of the normally open contact of the second EFC relay, and the second end of the normally open contact of the second EFC relay is connected to the first positive terminal of the second pitch control cabinet, the first input end of the third pitch control cabinet is connected to the first end of the normally open contact of the third EFC relay, the first end of the normally open contact of the third EFC relay is connected to the second end of the normally open contact of the third EFC relay, and the second end of the normally open contact of the third EFC relay is connected to the first positive terminal of the third pitch control cabinet.

[0011] Optionally, the EFC signal output end of the fan master control system is respectively connected to the first end of the coil of the first EFC relay, the first end of the coil of the second EFC relay, and the first end of the coil of the third EFC relay, and the negative end of the fan master control system is respectively connected to the second end of the coil of the first EFC relay, the second end of the coil of the second EFC relay, and the second end of the coil of the third EFC relay.

[0012] Optionally, the input end of the fan main control system is connected to the first end of the second normally open contact of the third safety position relay, the first end of the second normally open contact of the third safety position relay is connected to the second end of the second normally open contact of the third safety position relay, the second end of the second normally open contact of the third safety position relay is connected to the first end of the second normally open contact of the second safety position relay, the first end of the second normally open contact of the second safety position relay is connected to the second end of the second normally open contact of the second safety position relay, the second end of the second normally open contact of the second safety position relay is connected to the first end of the second normally open contact of the first safety position relay, and the first end of the second normally open contact of the first safety position relay is connected to the positive terminal of the fan main control system.

[0013] Optionally, the pitch control system further includes: a first charging selection relay, a second charging selection relay, and a third charging selection relay; The third output end of the first pitch control cabinet is connected to the first end of the coil of the first charging selection relay, the second end of the coil of the first charging selection relay is connected to the fourth negative end of the first pitch control cabinet, the second output end of the second pitch control cabinet is connected to the first end of the coil of the second charging selection relay, the second end of the coil of the second charging selection relay is connected to the fourth negative end of the second pitch control cabinet, the second output end of the third pitch control cabinet is connected to the first end of the coil of the third charging selection relay, the second end of the coil of the third charging selection relay is connected to the third negative end of the third pitch control cabinet, the second positive end of the first pitch control cabinet is connected to the first end of the first normally closed contact of the second charging selection relay, the first end of the first normally closed contact of the second charging selection relay is connected to the second end of the first normally closed contact of the second charging selection relay, the second end of the first normally closed contact of the second charging selection relay is connected to the first end of the first normally closed contact of the third charging selection relay, the first end of the first normally closed contact of the third charging selection relay is connected to the second end of the first normally closed contact of the third charging selection relay, and the second end of the first normally closed contact of the third charging selection relay is connected to the second input end of the first pitch control cabinet; The second positive terminal of the second pitch control cabinet is connected to the first end of the first normally closed contact of the first charging selection relay, the first end of the first normally closed contact of the first charging selection relay is connected to the second end of the first normally closed contact of the first charging selection relay, the second end of the first normally closed contact of the first charging selection relay is connected to the first end of the second normally closed contact of the third charging selection relay, the first end of the second normally closed contact of the third charging selection relay is connected to the second end of the second normally closed contact of the third charging selection relay, and the second end of the second normally closed contact of the third charging selection relay is connected to the second input terminal of the second pitch control cabinet; The second positive terminal of the third pitch control cabinet is connected to the first end of the second normally closed contact of the first charging selection relay, the first end of the second normally closed contact of the first charging selection relay is connected to the second end of the second normally closed contact of the first charging selection relay, the second end of the second normally closed contact of the first charging selection relay is connected to the first end of the second normally closed contact of the second charging selection relay, the first end of the second normally closed contact of the second charging selection relay is connected to the second end of the second normally closed contact of the second charging selection relay, and the second end of the second normally closed contact of the second charging selection relay is connected to the second input terminal of the third pitch control cabinet; The positive poles of the charging outputs of the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet are respectively connected to the positive pole of the backup power supply, and the negative poles of the charging outputs of the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet are respectively connected to the negative pole of the backup power supply.

[0014] In a second aspect of an embodiment of the present invention, a control method of a pitch control system is provided, which is implemented based on the pitch control system described above and includes: When it is monitored that the blade angles corresponding to the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet are all greater than the preset blade angle, the first end of the first normally open contact of the first safety position relay is connected to the second output end of the first pitch control cabinet, the second end of the first normally open contact of the first safety position relay is connected to the first end of the first normally open contact of the second safety position relay, the second end of the first normally open contact of the second safety position relay is connected to the first end of the first normally open contact of the third safety position relay, and the second end of the first normally open contact of the third safety position relay is connected to the first end of the coil of the first EFC relay, the first end of the coil of the second EFC relay and the first end of the coil of the third EFC relay; A high-level signal is generated through the second output end of the first pitch control cabinet, so that the coils of the first EFC relay, the second EFC relay and the third EFC relay are energized, so that the high-level signal generated at the first positive terminal of the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet is transmitted to the first input end of the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet through the normally open contact of the first EFC relay, the normally open contact of the second EFC relay and the normally open contact of the third EFC relay.

[0015] In a third aspect of the embodiments of the present invention, an electronic device is provided, including: a processor and a memory, the memory storing machine-readable instructions executable by the processor, and the machine-readable instructions, when executed by the processor, execute the control method of the pitch control system.

[0016] In an embodiment of the present invention, the pitch control system improves the power supply reliability through the redundant power supply design of the power grid system and the backup power supply. When the power grid is normal, the power grid is used to supply power. In case of a failure, the backup power supply takes over, thereby reducing downtime losses. The wind turbine main control system uniformly sends blade angle control instructions, which are independently executed by each pitch control cabinet to achieve efficient and precise adjustment of the blade angle and improve power generation efficiency. The perfect communication connection between the pitch control cabinets ensures the coordinated work of the system, facilitates management and troubleshooting, and improves the coordination and stability of the system as a whole.

[0017] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 is a schematic structural diagram of a pitch control system provided by an embodiment of the present invention; Figure 2 1 is a schematic diagram of a circuit structure of a pitch control system provided by an embodiment of the present invention; Figure 3 It is a circuit structure diagram of a pitch control system provided by another embodiment of the present invention.

[0019] Description of Reference Numerals 1-power grid system; 2-wind turbine main control system; 3-first variable pitch control cabinet; 4-second variable pitch control cabinet; 5-third variable pitch control cabinet; 6-backup power supply; 7-first safety position relay; 8-second safety position relay; 9-third safety position relay; 10-first EFC relay; 11- second EFC relay; 12- third EFC relay; 13-first charging selection relay; 14-second charging selection relay; 15-Third charge selection relay. DETAILED DESCRIPTION

[0020] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0022] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0023] Embodiment 1 Please refer to Figure 1 , Figure 11 is a schematic diagram of the structure of a pitch control system provided by an embodiment of the present invention, the pitch control system comprising: a power grid system 1, a wind turbine main control system 2, a first pitch control cabinet 3, a second pitch control cabinet 4, a third pitch control cabinet 5 and a backup power supply 6, the power grid system 1 is electrically connected to the wind turbine main control system 2, the wind turbine main control system 2 is respectively communicated and electrically connected to the first pitch control cabinet 3, the first pitch control cabinet 3 is respectively communicated and electrically connected to the second pitch control cabinet 4, the first pitch control cabinet 3 is also electrically connected to the third pitch control cabinet 5, the second pitch control cabinet 4 is also communicated and electrically connected to the third pitch control cabinet 5, the backup power supply 6 is respectively electrically connected to the first pitch control cabinet 3, the second pitch control cabinet 4 and the third pitch control cabinet 5, the first pitch control cabinet 3, the second pitch control cabinet 4 and the third pitch control cabinet 5 are all electrically connected to a pitch motor; the power grid system 1 is used to supply power to the first pitch control cabinet 3, the second pitch control cabinet 4 and the third pitch control cabinet 5. The control cabinet 4 and the third pitch control cabinet 5 are powered; the backup power supply 6 is used to supply power to the first pitch control cabinet 3, the second pitch control cabinet 4 and the third pitch control cabinet 5 when the power grid system 1 fails; the wind turbine main control system 2 is used to send the first blade angle control instruction, the second blade angle control instruction and the third blade angle control instruction to the first pitch control cabinet 3, the second pitch control cabinet 4 and the third pitch control cabinet 5 respectively; the first pitch control cabinet 3 is used to control the corresponding pitch motor to perform corresponding actions according to the first blade angle control instruction to adjust the angle of the corresponding blade; the second pitch control cabinet 4 is used to control the corresponding pitch motor to perform corresponding actions according to the second blade angle control instruction to adjust the angle of the corresponding blade; the third pitch control cabinet 5 is used to control the corresponding pitch motor to perform corresponding actions according to the third blade angle control instruction to adjust the angle of the corresponding blade.

[0024] The power grid system 1 is a huge and complex power network, which is composed of multiple links such as power generation, transmission, transformation, distribution and power consumption. It transmits the electric energy generated by different types of power plants (such as thermal power plants, hydropower plants, wind farms, photovoltaic power plants, etc.) over long distances through high-voltage transmission lines, and then distributes it to various user ends after the voltage is reduced after transformation at the substation to meet the power demand of social production and life.

[0025] The wind turbine master control system 2 is the core control unit of the wind turbine generator set, which is responsible for monitoring, controlling and adjusting the overall operating status of the wind turbine. By receiving real-time data from various components of the wind turbine (such as anemometers, wind vanes, pitch sensors, speed sensors, etc.), the master control system can accurately control key operations such as starting, stopping, pitch changing, yaw, and power regulation of the wind turbine according to preset control strategies and algorithms.

[0026] The pitch control cabinet (3, 4 and 5) is an important part of the pitch control system of the wind turbine. Each wind turbine usually has three blades, and each blade corresponds to a pitch control cabinet. The pitch control cabinet is mainly responsible for controlling the pitch angle of the blades. By adjusting the pitch angle, the angle between the blades and the wind direction is changed, thereby achieving power regulation and safety protection of the wind turbine. It receives instructions from the wind turbine main control system, drives the pitch motor to operate, and accurately controls the rotation angle of the blades.

[0027] The backup power supply 6 is a power supply device that can provide temporary power support for key equipment or systems when the main power supply fails or the power goes out. In the power grid system and wind turbine generator set, the backup power supply usually takes the form of supercapacitor modules, battery packs, uninterruptible power supplies (UPS), etc. It is usually in a charging standby state, and when an abnormality of the main power supply is detected, it can quickly switch and supply power to the load.

[0028] The pitch motor is a key actuator in the wind turbine pitch system and is mainly used to accurately adjust the pitch angle of the wind turbine blades.

[0029] Specifically, under normal working conditions, the power grid system 1 is responsible for supplying power to the first pitch control cabinet 3, the second pitch control cabinet 4 and the third pitch control cabinet 5, and providing power support for the entire pitch control system. As the control core, the wind turbine main control system 2 generates the first blade angle control instruction, the second blade angle control instruction and the third blade angle control instruction according to the actual operation requirements, and sends these instructions to the first pitch control cabinet 3. After receiving the instruction from the wind turbine main control system 2, the first pitch control cabinet 3 controls the pitch motor electrically connected thereto to perform the corresponding action according to the first blade angle control instruction, thereby adjusting the corresponding blade angle. The second pitch control cabinet 4 receives the instruction from the wind turbine main control system 2, controls the corresponding pitch motor action according to the second blade angle control instruction, and adjusts the angle of the corresponding blade. After receiving the third blade angle control instruction from the wind turbine main control system 2, the third pitch control cabinet 5 controls the corresponding pitch motor to perform the corresponding action, and finally completes the adjustment of the corresponding blade angle. When the power grid system 1 fails, the power supply task is taken over by the backup power supply 6. The backup power supply 6 is electrically connected to the first pitch control cabinet 3, the second pitch control cabinet 4 and the third pitch control cabinet 5. At this time, it supplies power to these three pitch control cabinets to ensure that the pitch control system can still work normally in the event of a power grid failure and maintain the blade angle regulation function.

[0030] In one embodiment, the pitch control system also includes: a braking resistor, a limit switch and a proximity switch; a braking circuit is arranged in the pitch control cabinet, the braking resistor is electrically connected to the braking circuit, the signal output end of the limit switch and the signal output end of the proximity switch are respectively electrically connected to the signal input end of the pitch control cabinet, the limit switch is set at the extreme position of the blade, and the proximity switch is set at the warning position of the blade; the external braking resistor is used to discharge the feedback energy generated when the pitch motor is in a braking state; the limit switch is used to send a pitch motor stop operation signal to the pitch control cabinet when the blade reaches the extreme position of the blade; the proximity switch is used to send a blade angle verification signal to the pitch control cabinet when the blade reaches a preset position; the pitch control cabinet is also used to control the pitch motor to stop running according to the pitch motor stop running signal; the pitch control cabinet is also used to control the pitch motor to decelerate according to the blade angle verification signal.

[0031] The braking resistor is mainly used to discharge the feedback energy generated when the pitch motor is in the braking state. When the pitch motor is braking, according to the law of conservation of energy, the kinetic energy of the motor will be converted into electrical energy. If this part of the electrical energy is not handled in time, it will have an adverse effect on the circuit of the entire system, such as causing excessive voltage and damaging circuit components. The braking resistor plays a key role in this process. It can dissipate the excess electrical energy generated by the pitch motor during braking in the form of heat energy, thereby maintaining the energy balance and electrical stability of the system. By electrically connecting the braking resistor to the braking circuit, a path for energy release is formed. When the motor brakes, the feedback electrical energy will pass through the braking resistor and be consumed in the form of heat, protecting the normal operation of the system.

[0032] The limit switch is set at the extreme position of the blade. In the entire pitch control system, the main task of the limit switch is to accurately monitor the position of the blade. When the blade reaches the extreme position, the limit switch will immediately send a signal to the pitch control cabinet to stop the pitch motor. This signal is very important, because once the blade reaches the extreme position, if the motor continues to run, it may cause damage to the mechanical parts, such as collision between the blade and other structures and other serious consequences.

[0033] The proximity switch is set at the blade angle calibration position. When the blade reaches this calibration position, the proximity switch will send a blade angle calibration signal to the pitch control cabinet. The function of this signal is to let the pitch control cabinet confirm whether there is a deviation between the actual mechanical position and the calculated position to avoid slippage of the blade root bearing gear and the motor bearing.

[0034] In one embodiment, the energy storage capacity of the backup power supply 6 is calculated in the following manner: Obtaining normal operating energy and fault operating energy of blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet; Calculate the sum of the normal operating energies of the blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet to obtain the total normal operating energy of the blades; Calculate the sum of the fault operation energies of the blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet to obtain the total fault operation energy of the blades; The sum of the total energy of the blade's normal operation and the total energy of the blade's fault operation is calculated, and the product of the sum and the preset safety factor is calculated to obtain the blade's guaranteed feathering energy; Based on the blade feathering energy and the voltage range in which the backup power supply can operate, the energy storage capacity of the backup power supply is obtained.

[0035] Specifically, based on the blade-guaranteed propeller-feathering energy and the voltage range in which the backup power supply can operate, the energy storage capacity of the backup power supply is obtained. This is a conventional technical means in the field and will not be described in detail here.

[0036] For example: when the grid voltage is normal, the maximum total energy required for the three blades to operate normally within 3s is 343kJ; after a grid failure, the maximum total energy required for the three blades to complete the propeller adjustment is 894kJ; therefore, if the safety factor is 1.3, the total energy required for the backup power supply of the pitch system is 1505.2kJ.

[0037] In this embodiment, the normal and faulty operating energies of the blades corresponding to the three pitch control cabinets are obtained, and their sums are calculated to obtain the total normal and faulty operating energies. The sum of the two is then multiplied by a preset safety factor to obtain the blade guaranteed operating energy, thereby providing a basis for selecting a suitable backup power supply and ensuring that the system can achieve emergency propeller alignment when the power grid system cannot operate normally.

[0038] In this embodiment, each pitch control cabinet is equipped with a safety position relay, which adopts a double-contact design; the first normally open contact of each safety position relay is connected in series and connected in series with the EFC self-test DO point of the integrated driver in the pitch control cabinet; the second normally open contact of each safety position relay is connected in series and fed back to the wind turbine master control. Specifically, Figure 2As shown, the pitch control system also includes: a first safety position relay 7, a second safety position relay 8, a third safety position relay 9, a first EFC relay 10, a second EFC relay 11 and a third EFC relay 12; a first output end of the first pitch control cabinet 3 is connected to a first end of the coil of the first safety position relay 7, a second end of the coil of the first safety position relay 7 is connected to a first negative terminal of the first pitch control cabinet 3, a second output end of the first pitch control cabinet 3 is connected to a first end of a first normally open contact of the first safety position relay 7, a first end of the first normally open contact of the first safety position relay 7 is connected to a second end of the first normally open contact of the first safety position relay 7, a second end of the first normally open contact of the first safety position relay 7 is connected to a first end of a first normally open contact of the second safety position relay 8, a first end of the first normally open contact of the second safety position relay 8 is connected to a second end of the first normally open contact of the second safety position relay 8, a second end of the first normally open contact of the second safety position relay 8 is connected to a first end of a first normally open contact of the third safety position relay 9, and a first normally open contact of the third safety position relay 9 is connected to a The first end of the point is connected to the second end of the first normally open contact of the third safety position relay 9, the second end of the first normally open contact of the third safety position relay 9 is respectively connected to the first end of the coil of the first EFC relay 10, the first end of the coil of the second EFC relay 11 and the first end of the coil of the third EFC relay 12, the second negative terminal of the first pitch control cabinet 3 is respectively connected to the second end of the coil of the first EFC relay 10, the second end of the coil of the second EFC relay 11 and the second end of the coil of the third EFC relay 12, the third negative terminal of the first pitch control cabinet 3 is connected to the first negative terminal of the second pitch control cabinet 4, the first output terminal of the second pitch control cabinet 4 is connected to the first end of the coil of the second safety position relay 8, the second end of the coil of the second safety position relay 8 is connected to the second negative terminal of the second pitch control cabinet 4, the third negative terminal of the second pitch control cabinet 4 is connected to the first negative terminal of the third pitch control cabinet 5, the first output terminal of the third pitch control cabinet 5 is connected to the first end of the coil of the third safety position relay 9, and the second end of the coil of the third safety position relay 9 is connected to the second negative terminal of the third pitch control cabinet 5.

[0039] like Figure 2As shown, the first input end of the first pitch control cabinet 3 is connected to the first end of the normally open contact of the first EFC relay 10, the first end of the normally open contact of the first EFC relay 10 is connected to the second end of the normally open contact of the first EFC relay 10, and the second end of the normally open contact of the first EFC relay 10 is connected to the first positive terminal of the first pitch control cabinet 3, the first input end of the second pitch control cabinet 4 is connected to the first end of the normally open contact of the second EFC relay 11, the first end of the normally open contact of the second EFC relay 11 is connected to the second end of the normally open contact of the second EFC relay 11, and the second end of the normally open contact of the second EFC relay 11 is connected to the first positive terminal of the second pitch control cabinet 4, the first input end of the third pitch control cabinet 5 is connected to the first end of the normally open contact of the third EFC relay 12, the first end of the normally open contact of the third EFC relay 12 is connected to the second end of the normally open contact of the third EFC relay 12, and the second end of the normally open contact of the third EFC relay 12 is connected to the first positive terminal of the third pitch control cabinet 5.

[0040] like Figure 2 As shown, the EFC signal output end of the fan master control system 2 is respectively connected to the first end of the coil of the first EFC relay 10, the first end of the coil of the second EFC relay 11 and the first end of the coil of the third EFC relay 12, and the negative terminal of the fan master control system 2 is respectively connected to the second end of the coil of the first EFC relay 10, the second end of the coil of the second EFC relay 11 and the second end of the coil of the third EFC relay 12.

[0041] The EFC signals input by each pitch control cabinet are connected in parallel and can be controlled by the wind turbine master control and pitch control cabinet. When the blade angle corresponding to each pitch control cabinet is greater than 85 degrees, the safety position relay contacts are energized, and the system EFC signal self-check can be performed through the DO point of the pitch control cabinet.

[0042] The specific working principle is: when the blade angle corresponding to each pitch control cabinet is greater than 85 degrees, the blade will trigger the proximity switch, and generate a high-level signal through the proximity switch to the first output end of the corresponding pitch control cabinet (the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet), so that the coils of the corresponding safety position relays (the first safety position relay, the second safety position relay and the third safety position relay) are energized, thereby closing the first normally open contact of the first safety position relay, the first normally open contact of the second safety position relay and the first normally open contact of the third safety position relay, thereby energizing the coils of the first EFC relay, the second EFC relay and the third EFC relay, and then The normally open contact of the first EFC relay is closed, the normally open contact of the second EFC relay is closed, and the normally open contact of the third EFC relay is closed. After the normally open contact of the first EFC relay is closed, the high-level signal generated by the first positive terminal of the first pitch control cabinet is sent to the first input terminal of the first pitch control cabinet through the closed normally open contact. After the normally open contact of the second EFC relay is closed, the high-level signal generated by the first positive terminal of the second pitch control cabinet is sent to the first input terminal of the second pitch control cabinet through the closed normally open contact. After the normally open contact of the third EFC relay is closed, the high-level signal generated by the first positive terminal of the third pitch control cabinet is sent to the first input terminal of the third pitch control cabinet through the closed normally open contact.

[0043] At the same time, during the operation of the blades, the wind turbine main control system of the present application can also perform self-inspection on the EFC relay circuit by sending a self-inspection signal. Specifically, when the blades are operating normally, the first normally open contacts of the first safety position relay, the second safety position relay and the third safety position relay are all in a disconnected state, and the coils of the first EFC relay, the second EFC relay and the third EFC relay are all in a de-energized state. During self-inspection, the EFC end of the wind turbine main control system generates a high-level signal, so that the circuit formed by the coils of the first EFC relay, the second EFC relay and the third EFC relay and the second negative terminal of the first pitch control cabinet is turned on, the coils of the first EFC relay, the second EFC relay and the third EFC relay are energized, and the normally open contacts of the first EFC relay, the second EFC relay and the third EFC relay are closed. If the input end of any pitch control cabinet does not receive the corresponding high-level signal, it indicates that the EFC relay circuit of the pitch control cabinet is abnormal, thereby realizing EFC self-inspection.

[0044] In one implementation, if Figure 2As shown, the input end of the fan main control system 2 is connected to the first end of the second normally open contact of the third safety position relay 9, the first end of the second normally open contact of the third safety position relay 9 is connected to the second end of the second normally open contact of the third safety position relay 9, the second end of the second normally open contact of the third safety position relay 9 is connected to the first end of the second normally open contact of the second safety position relay 8, the first end of the second normally open contact of the second safety position relay 8 is connected to the second end of the second normally open contact of the second safety position relay 8, the second end of the second normally open contact of the second safety position relay 8 is connected to the first end of the second normally open contact of the first safety position relay 7, and the first end of the second normally open contact of the first safety position relay 7 is connected to the positive terminal of the fan main control system 2.

[0045] In one embodiment, the pitch control system also includes: a first charging selection relay 13, a second charging selection relay 14 and a third charging selection relay 15; the third output end of the first pitch control cabinet 3 is connected to the first end of the coil of the first charging selection relay 13, the second end of the coil of the first charging selection relay 13 is connected to the fourth negative terminal of the first pitch control cabinet 3, the second output end of the second pitch control cabinet 4 is connected to the first end of the coil of the second charging selection relay 14, the second end of the coil of the second charging selection relay 14 is connected to the fourth negative terminal of the second pitch control cabinet 4, the second output end of the third pitch control cabinet 5 is connected to the line of the third charging selection relay 15 The first end of the coil of the third charging selection relay 15 is connected, the second end of the coil of the third charging selection relay 15 is connected to the third negative terminal of the third pitch control cabinet 5; the second positive terminal of the first pitch control cabinet 3 is connected to the first end of the first normally closed contact of the second charging selection relay 14, the first end of the first normally closed contact of the second charging selection relay 14 is connected to the second end of the first normally closed contact of the second charging selection relay 14, the second end of the first normally closed contact of the second charging selection relay 14 is connected to the first end of the first normally closed contact of the third charging selection relay 15, the first end of the first normally closed contact of the third charging selection relay 15 is connected to the second end of the first normally closed contact of the third charging selection relay 15 The second end of the first normally closed contact of the third charging selection relay 15 is connected to the second input end of the first pitch control cabinet 3, the second positive terminal of the second pitch control cabinet 4 is connected to the first end of the first normally closed contact of the first charging selection relay 13, the first end of the first normally closed contact of the first charging selection relay 13 is connected to the second end of the first normally closed contact of the first charging selection relay 13, the second end of the first normally closed contact of the first charging selection relay 13 is connected to the first end of the second normally closed contact of the third charging selection relay 15, the first end of the second normally closed contact of the third charging selection relay 15 is connected to the second end of the second normally closed contact of the third charging selection relay 15. Connection; the second end of the second normally closed contact of the third charging selection relay 15 is connected to the second input end of the second pitch control cabinet 4, the second positive terminal of the third pitch control cabinet 5 is connected to the first end of the second normally closed contact of the first charging selection relay 13, the first end of the second normally closed contact of the first charging selection relay 13 is connected to the second end of the second normally closed contact of the first charging selection relay 13, the second end of the second normally closed contact of the first charging selection relay 13 is connected to the first end of the second normally closed contact of the second charging selection relay 14, and the first end of the second normally closed contact of the second charging selection relay 14 is connected to the second end of the second normally closed contact of the second charging selection relay 14;The second end of the second normally closed contact of the second charging selection relay 14 is connected to the second input end of the third pitch control cabinet 5, the positive poles of the charging outputs of the first pitch control cabinet 3, the second pitch control cabinet 4, and the third pitch control cabinet 5 are respectively connected to the positive pole of the backup power supply 6, and the negative poles of the charging outputs of the first pitch control cabinet 3, the second pitch control cabinet 4, and the third pitch control cabinet 5 are respectively connected to the negative pole of the backup power supply 6. ;

[0046] The integrated driver in each variable pitch control cabinet can charge the backup power supply cabinet 6, and only one integrated driver is allowed to perform the charging function at the same time. The variable pitch control cabinet is equipped with a charging selection relay, which adopts a double-contact design. The normally closed contacts of the second charging selection relay 14 and the third charging selection relay 15 are connected in series and fed back to the DI point of the integrated drive of the third variable pitch control cabinet 5; the normally closed contacts of the first charging selection relay 13 and the third charging selection relay 15 are connected in series and fed back to the DI point of the integrated drive of the second variable pitch control cabinet 4; the normally closed contact of the second charging selection relay 14 and the normally closed contact of the first charging selection relay are connected in series and fed back to the DI point of the integrated drive of the first variable pitch control cabinet 3. When the charging function in this control cabinet is not selected, the normally closed contact of the relay remains energized, and the DI point detection is a high level; when the charging function is selected, the relay is energized, the normally closed contact is disconnected, and the DI point detection is a low level.

[0047] Each variable pitch control cabinet can enable or disable the backup power supply step-by-step charging function of the integrated drive according to the communication instructions of the wind turbine master control; when the integrated drive detects that the blade is in the parking position and the charging selection relay feedback DI signal is high, the step-by-step charging function can be enabled; when the variable pitch system is in the grid-connected operation state, it will not receive the wind turbine master control to enable or disable the step-by-step charging function.

[0048] The backup power supply of the variable pitch system is charged in two stages: In stage 1, if the rated input voltage Un is 400V and the undervoltage state is 320V (0.8Un) or below, the integrated drive performs 465V floating charge; In stage 2, if the input voltage is above 320V, it is further determined whether the backup power supply voltage is above 460V (the dead zone voltage U1 is 5V). If so, 480V to 500V cyclic charging is performed.

[0049] Specifically, the working principle is: when the first pitch control cabinet is selected for charging, the second output terminal of the first pitch control cabinet generates a high-level signal, so that the first normally closed contact of the first charging selection relay and the second normally closed contact of the first charging selection relay are disconnected, so that the second input points of the second pitch control cabinet and the third pitch control cabinet are low-level, and it is known that the charging function of the first pitch control cabinet has been enabled, and the charging function is prohibited in this pitch control cabinet. And so on for the second and third pitch control cabinets.

[0050] In one or more of the above embodiments, the positive terminal of each pitch control cabinet and the wind turbine main control system is 24V, and the negative terminal of each pitch control cabinet and the wind turbine main control system is 0V.

[0051] In an embodiment of the present invention, the pitch control system improves the power supply reliability through the redundant power supply design of the power grid system and the backup power supply. When the power grid is normal, the power grid is used to supply power. In case of a failure, the backup power supply takes over, thereby reducing downtime losses. The wind turbine main control system uniformly sends blade angle control instructions, which are independently executed by each pitch control cabinet to achieve efficient and precise adjustment of the blade angle and improve power generation efficiency. The perfect communication connection between the pitch control cabinets ensures the coordinated work of the system, facilitates management and troubleshooting, and improves the coordination and stability of the system as a whole.

[0052] Embodiment 2 Based on the same inventive concept, an embodiment of the present invention further provides a control method for a pitch control system, the method comprising the following steps: S100, when it is monitored that the blade angles corresponding to the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet are all greater than the preset blade angle, the first end of the first normally open contact of the first safety position relay is connected to the second output end of the first pitch control cabinet, the second end of the first normally open contact of the first safety position relay is connected to the first end of the first normally open contact of the second safety position relay, the second end of the first normally open contact of the second safety position relay is connected to the first end of the first normally open contact of the third safety position relay, and the second end of the first normally open contact of the third safety position relay is connected to the first end of the coil of the first EFC relay, the first end of the coil of the second EFC relay and the first end of the coil of the third EFC relay; S200, a high-level signal is generated through the second output end of the first pitch control cabinet, so that the coils of the first EFC relay, the second EFC relay and the third EFC relay are energized, so that the high-level signal generated by the first positive terminal of the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet is transmitted to the first input end of the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet through the normally open contact of the first EFC relay, the normally open contact of the second EFC relay and the normally open contact of the third EFC relay.

[0053] It should be understood that the method corresponds to the above control system embodiment, and the specific functions of the method can be referred to in the above description. To avoid repetition, the detailed description is appropriately omitted here. The device includes at least one software function module that can be stored in a memory in the form of software or firmware or solidified in the operating system (OS) of the device.

[0054] Embodiment 3 Based on the same inventive concept, an embodiment of the present invention further provides an electronic device, including: a processor and a memory, the memory storing machine-readable instructions executable by the processor, and the machine-readable instructions executing the above-mentioned control method of the pitch control system when executed by the processor.

[0055] In a typical configuration, an electronic device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0056] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0057] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0058] Embodiment 4 Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium storing computer instructions. When the computer instructions are executed on a computer, the computer executes the control method of the pitch control system described above.

[0059] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0060] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0061] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0062] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0063] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0064] In addition, the functional modules in each embodiment of the present application can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0065] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0066] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A variable pitch control system, characterized in that: include: A power grid system (1), a wind turbine main control system (2), a first pitch control cabinet (3), a second pitch control cabinet (4), a third pitch control cabinet (5) and a backup power supply (6); the power grid system (1) is electrically connected to the wind turbine main control system (2); the wind turbine main control system (2) is respectively connected to the first pitch control cabinet (3) in communication and in electrical connection; the first pitch control cabinet (3) is respectively connected to the second pitch control cabinet (4) in communication and in electrical connection; the first pitch control cabinet (3) is also electrically connected to the third pitch control cabinet (5); the second pitch control cabinet (4) is also connected to the third pitch control cabinet (5) in communication; the backup power supply (6) is respectively electrically connected to the first pitch control cabinet (3), the second pitch control cabinet (4) and the third pitch control cabinet (5); the first pitch control cabinet (3), the second pitch control cabinet (4) and the third pitch control cabinet (5) are all electrically connected to a pitch motor; A power grid system (1) for supplying power to a first pitch control cabinet (3), a second pitch control cabinet (4) and a third pitch control cabinet (5); A backup power supply (6) is used to supply power to the first variable pitch control cabinet (3), the second variable pitch control cabinet (4) and the third variable pitch control cabinet (5) when the power grid system (1) fails; A wind turbine main control system (2) is used to send a first blade angle control instruction, a second blade angle control instruction and a third blade angle control instruction to a first variable pitch control cabinet (3), a second variable pitch control cabinet (4) and a third variable pitch control cabinet (5) respectively; The first variable pitch control cabinet (3) is used to control the corresponding variable pitch motor to perform corresponding actions according to the first blade angle control instruction, so as to adjust the angle of the corresponding blade; The second variable pitch control cabinet (4) is used to control the corresponding variable pitch motor to perform corresponding actions according to the second blade angle control instruction, so as to adjust the angle of the corresponding blade; The third variable pitch control cabinet (5) is used to control the corresponding variable pitch motor to perform corresponding actions according to the third blade angle control instruction, so as to adjust the angle of the corresponding blade.

2. The pitch control system according to claim 1, characterized in that: The system also includes: a braking resistor, a limit switch and a proximity switch; A braking circuit is provided in the pitch control cabinet, the braking resistor is electrically connected to the braking circuit, the signal output end of the limit switch and the signal output end of the proximity switch are electrically connected to the signal input end of the pitch control cabinet respectively, the limit switch is set at the extreme position of the blade, and the proximity switch is set at the warning position of the blade; The external braking resistor is used to discharge the feedback energy generated when the pitch motor is in the braking state; The limit switch is used to send a signal to the pitch control cabinet to stop the pitch motor when the blade reaches the limit position of the blade; The proximity switch is used to send a blade angle calibration signal to the pitch control cabinet when the blade reaches the preset position; The pitch control cabinet is also used to control the pitch motor to stop running according to the pitch motor stop running signal; The pitch control cabinet is also used to check the signal according to the blade angle and control the pitch motor to decelerate.

3. The pitch control system according to claim 1, characterized in that: The energy storage capacity of the backup power supply (6) is calculated as follows: Obtaining normal operating energy and fault operating energy of blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet; Calculate the sum of the normal operating energies of the blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet to obtain the total normal operating energy of the blades; Calculate the sum of the fault operation energies of the blades corresponding to the first pitch control cabinet, the second pitch control cabinet, and the third pitch control cabinet to obtain the total fault operation energy of the blades; The sum of the total energy of the blade's normal operation and the total energy of the blade's fault operation is calculated, and the product of the sum and the preset safety factor is calculated to obtain the blade's guaranteed feathering energy; Based on the blade feathering energy and the voltage range in which the backup power supply can operate, the energy storage capacity of the backup power supply is obtained.

4. The pitch control system according to claim 1, characterized in that: The system further comprises: a first safety position relay (7), a second safety position relay (8), a third safety position relay (9), a first EFC relay (10), a second EFC relay (11) and a third EFC relay (12); The first output end of the first pitch control cabinet (3) is connected to the first end of the coil of the first safety position relay (7), the second end of the coil of the first safety position relay (7) is connected to the first negative terminal of the first pitch control cabinet (3), the second output end of the first pitch control cabinet (3) is connected to the first end of the first normally open contact of the first safety position relay (7), the first end of the first normally open contact of the first safety position relay (7) is connected to the second end of the first normally open contact of the first safety position relay (7), the second end of the first normally open contact of the first safety position relay (7) is connected to the first end of the first normally open contact of the second safety position relay (8), the first end of the first normally open contact of the second safety position relay (8) is connected to the second end of the first normally open contact of the second safety position relay (8), the second end of the first normally open contact of the second safety position relay (8) is connected to the first end of the first normally open contact of the third safety position relay (9), the first end of the first normally open contact of the third safety position relay (9) is connected to the second end of the first normally open contact of the third safety position relay (9), and the The second end of the first normally open contact is respectively connected to the first end of the coil of the first EFC relay (10), the first end of the coil of the second EFC relay (11), and the first end of the coil of the third EFC relay (12); the second negative terminal of the first pitch control cabinet (3) is respectively connected to the second end of the coil of the first EFC relay (10), the second end of the coil of the second EFC relay (11), and the second end of the coil of the third EFC relay (12); the third negative terminal of the first pitch control cabinet (3) is connected to the first negative terminal of the second pitch control cabinet (4); The first output end of the second pitch control cabinet (4) is connected to the first end of the coil of the second safety position relay (8), the second end of the coil of the second safety position relay (8) is connected to the second negative terminal of the second pitch control cabinet (4), the third negative terminal of the second pitch control cabinet (4) is connected to the first negative terminal of the third pitch control cabinet (5), the first output end of the third pitch control cabinet (5) is connected to the first end of the coil of the third safety position relay (9), and the second end of the coil of the third safety position relay (9) is connected to the second negative terminal of the third pitch control cabinet (5).

5. The pitch control system according to claim 4, characterized in that: The first input end of the first pitch control cabinet (3) is connected to the first end of the normally open contact of the first EFC relay (10), the first end of the normally open contact of the first EFC relay (10) is connected to the second end of the normally open contact of the first EFC relay (10), the second end of the normally open contact of the first EFC relay (10) is connected to the first positive terminal of the first pitch control cabinet (3), the first input end of the second pitch control cabinet (4) is connected to the first end of the normally open contact of the second EFC relay (11), the first end of the normally open contact of the second EFC relay (11) is connected to the first positive terminal of the first pitch control cabinet (3), The second end of the normally open contact of the second EFC relay (11) is connected, the second end of the normally open contact of the second EFC relay (11) is connected to the first positive terminal of the second pitch control cabinet (4), the first input end of the third pitch control cabinet (5) is connected to the first end of the normally open contact of the third EFC relay (12), the first end of the normally open contact of the third EFC relay (12) is connected to the second end of the normally open contact of the third EFC relay (12), and the second end of the normally open contact of the third EFC relay (12) is connected to the first positive terminal of the third pitch control cabinet (5).

6. The pitch control system according to claim 4, characterized in that: The EFC signal output end of the fan main control system (2) is respectively connected to the first end of the coil of the first EFC relay (10), the first end of the coil of the second EFC relay (11), and the first end of the coil of the third EFC relay (12), and the negative terminal of the fan main control system (2) is respectively connected to the second end of the coil of the first EFC relay (10), the second end of the coil of the second EFC relay (11), and the second end of the coil of the third EFC relay (12).

7. The pitch control system according to claim 4, characterized in that: The input end of the fan main control system (2) is connected to the first end of the second normally open contact of the third safety position relay (9), the first end of the second normally open contact of the third safety position relay (9) is connected to the second end of the second normally open contact of the third safety position relay (9), the second end of the second normally open contact of the third safety position relay (9) is connected to the first end of the second normally open contact of the second safety position relay (8), the first end of the second normally open contact of the second safety position relay (8) is connected to the second end of the second normally open contact of the second safety position relay (8), the second end of the second normally open contact of the second safety position relay (8) is connected to the first end of the second normally open contact of the first safety position relay (7), and the first end of the second normally open contact of the first safety position relay (7) is connected to the positive terminal of the fan main control system (2).

8. The pitch control system according to claim 4, characterized in that: The system further comprises: a first charging selection relay (13), a second charging selection relay (14) and a third charging selection relay (15); The third output end of the first pitch control cabinet (3) is connected to the first end of the coil of the first charging selection relay (13), the second end of the coil of the first charging selection relay (13) is connected to the fourth negative terminal of the first pitch control cabinet (3), the second output end of the second pitch control cabinet (4) is connected to the first end of the coil of the second charging selection relay (14), the second end of the coil of the second charging selection relay (14) is connected to the fourth negative terminal of the second pitch control cabinet (4), the second output end of the third pitch control cabinet (5) is connected to the first end of the coil of the third charging selection relay (15), and the second end of the coil of the third charging selection relay (15) is connected to the third negative terminal of the third pitch control cabinet (5); The second positive terminal of the first pitch control cabinet (3) is connected to the first end of the first normally closed contact of the second charging selection relay (14), the first end of the first normally closed contact of the second charging selection relay (14) is connected to the second end of the first normally closed contact of the second charging selection relay (14), the second end of the first normally closed contact of the second charging selection relay (14) is connected to the first end of the first normally closed contact of the third charging selection relay (15), and the first end of the first normally closed contact of the third charging selection relay (15) is connected to the second end of the first normally closed contact of the third charging selection relay (15); The second end of the first normally closed contact of the third charging selection relay (15) is connected to the second input end of the first pitch control cabinet (3), the second positive terminal of the second pitch control cabinet (4) is connected to the first end of the first normally closed contact of the first charging selection relay (13), the first end of the first normally closed contact of the first charging selection relay (13) is connected to the second end of the first normally closed contact of the first charging selection relay (13), the second end of the first normally closed contact of the first charging selection relay (13) is connected to the first end of the second normally closed contact of the third charging selection relay (15), and the first end of the second normally closed contact of the third charging selection relay (15) is connected to the second end of the second normally closed contact of the third charging selection relay (15); The second end of the second normally closed contact of the third charging selection relay (15) is connected to the second input end of the second pitch control cabinet (4), the second positive terminal of the third pitch control cabinet (5) is connected to the first end of the second normally closed contact of the first charging selection relay (13), the first end of the second normally closed contact of the first charging selection relay (13) is connected to the second end of the second normally closed contact of the first charging selection relay (13), the second end of the second normally closed contact of the first charging selection relay (13) is connected to the first end of the second normally closed contact of the second charging selection relay (14), and the first end of the second normally closed contact of the second charging selection relay (14) is connected to the second end of the second normally closed contact of the second charging selection relay (14); The second end of the second normally closed contact of the second charging selection relay (14) is connected to the second input end of the third pitch control cabinet (5); the positive poles of the charging outputs of the first pitch control cabinet (3), the second pitch control cabinet (4), and the third pitch control cabinet (5) are respectively connected to the positive pole of the backup power supply (6); and the negative poles of the charging outputs of the first pitch control cabinet (3), the second pitch control cabinet (4), and the third pitch control cabinet (5) are respectively connected to the negative pole of the backup power supply (6).

9. A control method for a pitch control system, implemented based on the pitch control system according to any one of claims 4 to 7, characterized in that: include: When it is monitored that the blade angles corresponding to the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet are all greater than the preset blade angle, the first end of the first normally open contact of the first safety position relay is connected to the second output end of the first pitch control cabinet, the second end of the first normally open contact of the first safety position relay is connected to the first end of the first normally open contact of the second safety position relay, the second end of the first normally open contact of the second safety position relay is connected to the first end of the first normally open contact of the third safety position relay, and the second end of the first normally open contact of the third safety position relay is connected to the first end of the coil of the first EFC relay, the first end of the coil of the second EFC relay and the first end of the coil of the third EFC relay; A high-level signal is generated through the second output end of the first pitch control cabinet, so that the coils of the first EFC relay, the second EFC relay and the third EFC relay are energized, so that the high-level signal generated at the first positive terminal of the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet is transmitted to the first input end of the first pitch control cabinet, the second pitch control cabinet and the third pitch control cabinet through the normally open contact of the first EFC relay, the normally open contact of the second EFC relay and the normally open contact of the third EFC relay.

10. An electronic device, characterized in that: include: A processor and a memory, wherein the memory stores machine-readable instructions executable by the processor, and when the machine-readable instructions are executed by the processor, the control method of the pitch control system according to claim 9 is executed.

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