A safe shutdown control method and system for an offshore floating wind turbine

Abstract

The present invention discloses a safe shutdown control method and system for an offshore floating wind turbine, comprising: 1) collecting the platform inclination angle of the floating wind turbine and performing data processing to obtain the platform pitch effective inclination angle and the platform lateral effective inclination angle of the floating wind turbine; 2) calculating the additional pitch variable pitch rate based on the platform pitch effective inclination angle, which is used to suppress the pitch movement of the floating wind turbine during the shutdown process; calculating the additional lateral variable pitch rate based on the platform lateral effective inclination angle, which is used to suppress the lateral movement of the floating wind turbine during the shutdown process; 3) superimposing the additional pitch variable pitch rate, the additional lateral variable pitch rate and the shutdown variable pitch rate, performing integral operation to obtain the final variable pitch command and sending it to the variable pitch system to execute the shutdown. The present invention realizes the safe shutdown of the unit by adding auxiliary variable pitch control during the shutdown process, actively controlling the pitch movement and lateral movement of the floating wind turbine during the shutdown process.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine control, and in particular to a safe shutdown control method, system, storage medium and computing device for an offshore floating wind turbine. Background Art

[0002] With the development of wind power technology, offshore wind power has gradually matured and is advancing towards the deep sea. For offshore and shallow waters, the foundation of wind turbines mainly adopts fixed foundations, such as monopile foundations and pipe frame foundations; for deep sea and offshore, since the cost of using fixed foundations will increase sharply, floating foundations will be the best solution. The potential of wind resources in the deep sea is huge, so floating offshore wind power will occupy a dominant position in future wind power development. For floating wind turbines, since their foundations float on the water surface rather than being fixed, under the combined action of wind, waves and currents, the foundation platform of the floating wind turbine will move or tilt relative to the water surface. When a fault or extreme sea conditions occur, the wind turbine needs to be shut down immediately. The traditional shutdown logic is that the blades are feathered at a fixed rate. However, for offshore floating wind turbines, the wind rotor thrust is unloaded during the shutdown process, causing the floating wind turbine to shake violently back and forth or even capsize; and the wind rotor speed decreases rapidly, generating a huge rollover inertia moment. When the lateral stability of the foundation platform of the floating wind turbine is insufficient, it is easy to cause the unit to roll over. Summary of the invention

[0003] The first purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and provide a safe shutdown control method for an offshore floating wind turbine set. By adding auxiliary pitch control during the shutdown process, the pitch movement and lateral movement of the floating wind turbine set are actively controlled during the shutdown process to achieve safe shutdown of the set.

[0004] A second object of the present invention is to provide a safe shutdown control system for an offshore floating wind turbine.

[0005] A third object of the present invention is to provide a storage medium.

[0006] A fourth object of the present invention is to provide a computing device.

[0007] The first object of the present invention is achieved by the following technical solution: A safe shutdown control method for an offshore floating wind turbine, performing the following operations:

[0008] 1) Collecting the platform inclination angle of the floating wind turbine and performing data processing to obtain the platform pitch effective inclination angle and platform lateral effective inclination angle of the floating wind turbine;

[0009] 2) Based on the effective pitch angle of the platform of the floating wind turbine, the additional pitch variable pitch rate is calculated to suppress the pitch movement of the floating wind turbine during the shutdown process; based on the effective lateral tilt angle of the platform of the floating wind turbine, the additional lateral variable pitch rate is calculated to suppress the lateral movement of the floating wind turbine during the shutdown process;

[0010] 3) The pitch additional pitch rate, the lateral additional pitch rate and the shutdown pitch rate are superimposed, and the final pitch command is obtained by integration operation and sent to the pitch system to execute shutdown.

[0011] Further, in step 1), the platform inclination of the floating wind turbine is collected by an inclination sensor, the inclination sensor is installed on the floating platform of the floating wind turbine, moves together with the floating platform, and collects the pitch inclination and lateral inclination of the floating platform in real time. A plurality of inclination sensors can be installed on the floating platform, and redundant inclination sensors can increase the reliability of the platform inclination measurement. If a plurality of inclination sensors are used, the platform inclination can be obtained by weighting the plurality of inclination measurement values;

[0012] The specific formula for the platform pitch angle is as follows:

[0013]

[0014] In the above formula, Indicates the platform pitch angle; θ fa,1 represents the pitch angle measured by the tilt sensor 1; η fa,1 Represents the weighting coefficient of the tilt sensor 1; θ fa,2 represents the pitch angle measured by the tilt sensor 2; η fa,2 represents the weighting coefficient of the tilt sensor 2; θ fa,n represents the pitch angle measured by the tilt sensor n; η fa,n Represents the weighting coefficient of the tilt sensor n; weighting coefficient η fa,1 , η fa,2 to η fa,n The value range is between 0 and 1. The sensor with high precision selects a large weighting coefficient and satisfies the sum of the weighting coefficients η fa,1 +η fa,2 +…+η fa,n is equal to 1;

[0015] The specific formula for the platform lateral inclination angle is as follows:

[0016]

[0017] In the above formula, Indicates the lateral inclination angle of the platform; θ ss,1 represents the lateral tilt angle measured by the tilt sensor 1; η ss,1Represents the weighting coefficient of the tilt sensor 1; θ ss,2 represents the lateral tilt angle measured by the tilt sensor 2; η ss,2 represents the weighting coefficient of the tilt sensor 2; θ ss,n represents the lateral tilt angle measured by the tilt sensor n; η ss,n Represents the weighting coefficient of the tilt sensor n; weighting coefficient η ss,1 , η ss,2 to η ss,n The value range is between 0 and 1. The sensor with high precision selects a large weighting coefficient and satisfies the sum of the weighting coefficients η ss,1 +η ss,2 +…+η ss,n is equal to 1;

[0018] In order to avoid interference of high-frequency noise, transmission chain frequency and 3P frequency on the measurement data, necessary filtering is performed on the platform pitch inclination angle and the platform lateral inclination angle. The filter includes low-pass filtering and band-stop filtering to attenuate the high-frequency components in the platform inclination angle data. The filtered platform pitch inclination angle is called the platform pitch effective inclination angle, and the filtered platform lateral inclination angle is called the platform lateral effective inclination angle. The specific formula is as follows:

[0019]

[0020] In the above formula, θ fa,F Indicates the effective pitch angle of the platform; F fa (s) represents the platform pitch angle filter; Indicates the platform pitch angle; θ ss,F Indicates the effective lateral inclination angle of the platform; F ss (s) represents the platform lateral tilt filter; Indicates the lateral inclination angle of the platform.

[0021] Further, in step 2), the additional pitch rate can generate additional thrust on the rotor side of the floating wind turbine, which is opposite to the pitch motion speed of the platform, thereby suppressing the pitch motion of the platform;

[0022] The effective pitch angle of the platform is differentially calculated and then proportionally controlled to obtain the additional pitch rate. The specific formula is as follows:

[0023]

[0024] In the above formula, δ fa,1 represents the additional pitch rate of blade 1; δ fa,2 represents the additional pitch rate of blade 2; δ fa,3 A represents the additional pitch rate of blade 3; fa represents the pitch motion suppression proportional gain; θ fa,FIndicates the effective pitch angle of the platform; dθ fa,F / dt represents the rate of change of the effective pitch angle of the platform.

[0025] Further, in step 2), the lateral additional pitch rate can generate lateral thrust on the rotor side of the floating wind turbine, which is opposite to the lateral movement speed of the platform, thereby suppressing the lateral movement of the platform;

[0026] The platform's lateral effective inclination angle is subjected to differential calculation and then to proportional control, and then a sine function is introduced to obtain the lateral additional pitch rate. The specific formula is as follows:

[0027]

[0028] In the above formula, δ ss,1 represents the lateral additional pitch rate of blade 1; δ ss,2 represents the lateral additional pitch rate of blade 2; δ ss,3 A represents the lateral additional pitch rate of blade 3; ss represents the lateral motion suppression proportional gain; θ ss,F Indicates the effective lateral inclination angle of the platform; dθ ss,F / dt represents the rate of change of the effective lateral tilt angle of the platform; represents the azimuth angle of blade 1; represents the azimuth angle of blade 2; represents the azimuth angle of blade 3; ω r Indicates the measured speed of the wind rotor; τ indicates the time delay of the pitch control system.

[0029] Further, in step 3), the pitch additional pitch rate, the lateral additional pitch rate and the shutdown pitch rate of the three blades are respectively superimposed and integrated to obtain the final pitch command. The specific formula is as follows:

[0030]

[0031] In the above formula, β1 represents the blade 1 stop pitch angle command; β2 represents the blade 2 stop pitch angle command; β3 represents the blade 3 stop pitch angle command; δ fa,1 represents the additional pitch rate of blade 1; δ fa,2 represents the additional pitch rate of blade 2; δ fa,3 represents the additional pitch rate of blade 3; δ ss,1 represents the lateral additional pitch rate of blade 1; δ ss,2 represents the lateral additional pitch rate of blade 2; δ ss,3 represents the lateral additional pitch rate of blade 3; δ c,1 Indicates the blade 1 stop pitch rate output by the pitch controller; δ c,2Indicates the blade 2 stop pitch rate output by the pitch controller; δ c,3 represents the blade 3 stop pitch rate output by the pitch controller; ∫dt represents the integral of time; β max Indicates the maximum pitch angle when the engine is stopped; min{} indicates the minimum value is taken when comparing the two.

[0032] The second object of the present invention is achieved by the following technical solution: a safe shutdown control system for an offshore floating wind turbine, used to implement the above-mentioned safe shutdown control method for an offshore floating wind turbine, comprising:

[0033] The platform inclination angle measurement module is used to collect the platform inclination angle of the floating wind turbine and perform data processing to obtain the platform pitch effective inclination angle and platform lateral effective inclination angle of the floating wind turbine;

[0034] The pitch motion suppression module calculates the additional pitch rate based on the effective pitch angle of the platform of the floating wind turbine, which is used to suppress the pitch motion of the floating wind turbine during the shutdown process;

[0035] The lateral motion suppression module calculates the lateral additional pitch rate based on the lateral effective inclination angle of the platform of the floating wind turbine, which is used to suppress the lateral motion of the floating wind turbine during the shutdown process;

[0036] The pitch command superposition module is used to superimpose the pitch additional pitch rate, the lateral additional pitch rate and the shutdown pitch rate, obtain the final pitch command through integral operation and send it to the pitch system to execute shutdown.

[0037] The third object of the present invention is achieved through the following technical solution: a storage medium stores a program, and when the program is executed by a processor, the above-mentioned safe shutdown control method of the offshore floating wind turbine is implemented.

[0038] The fourth objective of the present invention is achieved through the following technical solution: a computing device, comprising a processor and a memory for storing a program executable by the processor, wherein when the processor executes the program stored in the memory, the above-mentioned safe shutdown control method of the offshore floating wind turbine is implemented.

[0039] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0040] 1. The pitch additional pitch rate calculated and output in the solution of the present invention can generate a pitch thrust during the shutdown of the floating wind turbine, which is opposite to the pitch motion speed of the turbine platform, thereby suppressing the pitch motion of the platform.

[0041] 2. The lateral additional pitch rate calculated and output in the solution of the present invention can generate lateral thrust during the shutdown of the floating wind turbine, which is opposite to the lateral movement speed of the turbine platform, thereby suppressing the pitch movement of the platform.

[0042] 3. The scheme of the present invention adopts the inclination sensor of the floating platform and adopts the variable pitch rate during the shutdown process to suppress the pitch and lateral movement of the platform, thereby realizing a safe and stable shutdown control process of the unit without increasing the hardware cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the system of the present invention.

[0044] Figure 2 It is a logic block diagram of the system of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0046] Example 1

[0047] This embodiment discloses a safe shutdown control method for an offshore floating wind turbine, which performs the following operations:

[0048] 1) The platform inclination angle of the floating wind turbine is collected by an inclination sensor and data is processed to obtain the platform pitch effective inclination angle and the platform lateral effective inclination angle of the floating wind turbine;

[0049] The inclination sensor is installed on the floating platform of the floating wind turbine generator set, moves together with the floating platform, and collects the pitch inclination and lateral inclination of the floating platform in real time. Multiple inclination sensors can be installed on the floating platform. Redundant inclination sensors can increase the reliability of the platform inclination measurement. If multiple inclination sensors are used, multiple inclination measurement values ​​can be used to obtain the platform inclination in a weighted manner.

[0050] The specific formula for the platform pitch angle is as follows:

[0051]

[0052] In the above formula, Indicates the platform pitch angle; θ fa,1 represents the pitch angle measured by the tilt sensor 1; η fa,1 Represents the weighting coefficient of the tilt sensor 1; θ fa,2 represents the pitch angle measured by the tilt sensor 2; η fa,2 represents the weighting coefficient of the tilt sensor 2; θ fa,n represents the pitch angle measured by the tilt sensor n; η fa,nRepresents the weighting coefficient of the tilt sensor n; weighting coefficient η fa,1 , η fa,2 to η fa,n The value range is between 0 and 1. The sensor with high precision selects a large weighting coefficient and satisfies the sum of the weighting coefficients η fa,1 +η fa,2 +…+η fa,n is equal to 1;

[0053] The specific formula for the platform lateral inclination angle is as follows:

[0054]

[0055] In the above formula, Indicates the lateral inclination angle of the platform; θ ss,1 represents the lateral tilt angle measured by the tilt sensor 1; η ss,1 Represents the weighting coefficient of the tilt sensor 1; θ ss,2 represents the lateral tilt angle measured by the tilt sensor 2; η ss,2 represents the weighting coefficient of the tilt sensor 2; θ ss,n represents the lateral tilt angle measured by the tilt sensor n; η ss,n Represents the weighting coefficient of the tilt sensor n; weighting coefficient η ss,1 , η ss,2 to η ss,n The value range is between 0 and 1. The sensor with high precision selects a large weighting coefficient and satisfies the sum of the weighting coefficients η ss,1 +η ss,2 +…+η ss,n is equal to 1;

[0056] In order to avoid interference of high-frequency noise, transmission chain frequency and 3P frequency on the measurement data, necessary filtering is performed on the platform pitch inclination angle and the platform lateral inclination angle. The filter includes low-pass filtering and band-stop filtering to attenuate the high-frequency components in the platform inclination angle data. The filtered platform pitch inclination angle is called the platform pitch effective inclination angle, and the filtered platform lateral inclination angle is called the platform lateral effective inclination angle. The specific formula is as follows:

[0057]

[0058] In the above formula, θ fa,F Indicates the effective pitch angle of the platform; F fa (s) represents the platform pitch angle filter; Indicates the platform pitch angle; θ ss,F Indicates the effective lateral inclination angle of the platform; F ss (s) represents the platform lateral tilt filter; Indicates the lateral inclination angle of the platform.

[0059] 2) Based on the effective pitch angle of the platform of the floating wind turbine, the additional pitch rate is calculated to suppress the pitch motion of the floating wind turbine during the shutdown process;

[0060] When the unit enters the shutdown logic, the pitch controller outputs a fixed shutdown pitch rate command. At the fixed pitch rate, the thrust of the wind rotor drops sharply, and the floating wind turbine unit shakes violently back and forth, threatening the safety of the unit. Therefore, during the unit shutdown process, the additional pitch pitch rate is calculated according to the effective pitch angle of the platform. This additional pitch pitch rate can generate additional thrust on the rotor side of the floating wind turbine unit, which is opposite to the pitch motion speed of the platform, thereby suppressing the pitch motion of the platform.

[0061] The effective pitch angle of the platform is differentially calculated and then proportionally controlled to obtain the additional pitch rate. The specific formula is as follows:

[0062]

[0063] In the above formula, δ fa,1 represents the additional pitch rate of blade 1; δ fa,2 represents the additional pitch rate of blade 2; δ fa,3 A represents the additional pitch rate of blade 3; fa represents the pitch motion suppression proportional gain; θ fa,F Indicates the effective pitch angle of the platform; dθ fa,F / dt represents the rate of change of the effective pitch angle of the platform.

[0064] Based on the lateral effective inclination angle of the platform of the floating wind turbine, the lateral additional pitch rate is calculated to suppress the lateral movement of the floating wind turbine during the shutdown process.

[0065] When the unit enters the shutdown logic, the pitch controller outputs a fixed shutdown pitch rate command. At the fixed pitch rate, the rotation speed of the wind rotor drops sharply. Due to the huge inertia moment generated by the wind rotor, the floating wind turbine unit experiences violent lateral shaking, threatening the safety of the unit. Therefore, during the unit shutdown process, the lateral additional pitch rate is calculated according to the effective lateral inclination angle of the platform through independent pitch change. This lateral additional pitch rate can generate lateral thrust on the rotor side of the floating wind turbine unit, which is opposite to the lateral movement speed of the platform, thereby suppressing the lateral movement of the platform.

[0066] The platform's lateral effective inclination angle is subjected to differential calculation and then to proportional control, and then a sine function is introduced to obtain the lateral additional pitch rate. The specific formula is as follows:

[0067]

[0068] In the above formula, δss,1 represents the lateral additional pitch rate of blade 1; δ ss,2 represents the lateral additional pitch rate of blade 2; δ ss,3 A represents the lateral additional pitch rate of blade 3; ss represents the lateral motion suppression proportional gain; θ ss,F Indicates the effective lateral inclination angle of the platform; dθ ss,F / dt represents the rate of change of the effective lateral tilt angle of the platform; represents the azimuth angle of blade 1; represents the azimuth angle of blade 2; represents the azimuth angle of blade 3; ω r Indicates the measured speed of the wind rotor; τ indicates the time delay of the pitch control system.

[0069] 3) The pitch additional pitch rate, lateral additional pitch rate and shutdown pitch rate of the three blades are superimposed respectively, and the final pitch command is obtained by integration operation and sent to the pitch system to execute shutdown. The specific formula is as follows:

[0070]

[0071] In the above formula, β1 represents the blade 1 stop pitch angle command; β2 represents the blade 2 stop pitch angle command; β3 represents the blade 3 stop pitch angle command; δ fa,1 represents the additional pitch rate of blade 1; δ fa,2 represents the additional pitch rate of blade 2; δ fa,3 represents the additional pitch rate of blade 3; δ ss,1 represents the lateral additional pitch rate of blade 1; δ ss,2 represents the lateral additional pitch rate of blade 2; δ ss,3 represents the lateral additional pitch rate of blade 3; δ c,1 Indicates the blade 1 stop pitch rate output by the pitch controller; δ c,2 Indicates the blade 2 stop pitch rate output by the pitch controller; δ c,3 represents the blade 3 stop pitch rate output by the pitch controller; ∫dt represents the integral of time; β max Indicates the maximum pitch angle when the engine is stopped; min{} indicates the minimum value is taken when comparing the two.

[0072] Example 2

[0073] This embodiment discloses a safe shutdown control system for an offshore floating wind turbine, which is used to implement the safe shutdown control method for an offshore floating wind turbine described in Example 1. Figure 1 and Figure 2 As shown, the system includes the following functional modules:

[0074] The platform inclination angle measurement module is used to collect the platform inclination angle of the floating wind turbine and perform data processing to obtain the platform pitch effective inclination angle and platform lateral effective inclination angle of the floating wind turbine;

[0075] The pitch motion suppression module calculates the additional pitch rate based on the effective pitch angle of the platform of the floating wind turbine, which is used to suppress the pitch motion of the floating wind turbine during the shutdown process;

[0076] The lateral motion suppression module calculates the lateral additional pitch rate based on the lateral effective inclination angle of the platform of the floating wind turbine, which is used to suppress the lateral motion of the floating wind turbine during the shutdown process;

[0077] The pitch command superposition module is used to superimpose the pitch additional pitch rate, the lateral additional pitch rate and the shutdown pitch rate, obtain the final pitch command through integral operation and send it to the pitch system to execute shutdown.

[0078] Example 3

[0079] This embodiment discloses a storage medium storing a program. When the program is executed by a processor, the safe shutdown control method for an offshore floating wind turbine set described in Embodiment 1 is implemented.

[0080] The storage medium in this embodiment can be a disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a USB flash drive, a mobile hard disk, or other media.

[0081] Example 4

[0082] This embodiment discloses a computing device, including a processor and a memory for storing a program executable by the processor. When the processor executes the program stored in the memory, the safe shutdown control method for the offshore floating wind turbine set described in Example 1 is implemented.

[0083] The computing device described in this embodiment may be a desktop computer, a laptop computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal devices with a processor function.

[0084] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A safe shutdown control method for an offshore floating wind turbine, characterized in that: Do the following: 1) Collecting the platform inclination angle of the floating wind turbine and performing data processing to obtain the platform pitch effective inclination angle and platform lateral effective inclination angle of the floating wind turbine; The platform inclination of the floating wind turbine is collected by an inclination sensor. The inclination sensor is installed on the floating platform of the floating wind turbine and moves together with the floating platform to collect the pitch inclination and lateral inclination of the floating platform in real time. Multiple inclination sensors can be installed on the floating platform. Redundant inclination sensors can increase the reliability of platform inclination measurement. If multiple inclination sensors are used, multiple inclination measurement values ​​can be used to obtain the platform inclination in a weighted manner. The specific formula for the platform pitch angle is as follows: In the above formula, Indicates the platform pitch angle; θ fa,1 represents the pitch angle measured by the tilt sensor 1; η fa,1 Represents the weighting coefficient of the tilt sensor 1; θ fa,2 represents the pitch angle measured by the tilt sensor 2; η fa,2 represents the weighting coefficient of the tilt sensor 2; θ fa,n represents the pitch angle measured by the tilt sensor n; η fa,n Represents the weighting coefficient of the tilt sensor n; weighting coefficient η fa,1 , η fa,2 to η fa,n The value range is between 0 and 1. The sensor with high precision selects a large weighting coefficient and satisfies the sum of the weighting coefficients η fa,1 +η fa,2 +…+η fa,n is equal to 1; The specific formula for the platform lateral inclination angle is as follows: In the above formula, Indicates the lateral inclination angle of the platform; θ ss,1 represents the lateral tilt angle measured by the tilt sensor 1; η ss,1 Represents the weighting coefficient of the tilt sensor 1; θ ss,2 represents the lateral tilt angle measured by the tilt sensor 2; η ss,2 represents the weighting coefficient of the tilt sensor 2; θ ss,n represents the lateral tilt angle measured by the tilt sensor n; η ss,n Represents the weighting coefficient of the tilt sensor n; weighting coefficient η ss,1 , η ss,2 to η ss,n The value range is between 0 and 1. The sensor with high precision selects a large weighting coefficient and satisfies the sum of the weighting coefficients η ss,1 +η ss,2 +…+η ss,n is equal to 1; In order to avoid interference of high-frequency noise, transmission chain frequency and 3P frequency on the measurement data, necessary filtering is performed on the platform pitch inclination angle and the platform lateral inclination angle. The filter includes low-pass filtering and band-stop filtering to attenuate the high-frequency components in the platform inclination angle data. The filtered platform pitch inclination angle is called the platform pitch effective inclination angle, and the filtered platform lateral inclination angle is called the platform lateral effective inclination angle. The specific formula is as follows: In the above formula, θ fa,F Indicates the effective pitch angle of the platform; F fa (s) represents the platform pitch angle filter; Indicates the platform pitch angle; θ ss,F Indicates the effective lateral inclination angle of the platform; F ss (s) represents the platform lateral tilt filter; Indicates the lateral inclination angle of the platform; 2) Based on the effective pitch angle of the platform of the floating wind turbine, the additional pitch variable pitch rate is calculated to suppress the pitch movement of the floating wind turbine during the shutdown process; based on the effective lateral tilt angle of the platform of the floating wind turbine, the additional lateral variable pitch rate is calculated to suppress the lateral movement of the floating wind turbine during the shutdown process; 3) The pitch additional pitch rate, the lateral additional pitch rate and the shutdown pitch rate are superimposed, and the final pitch command is obtained by integration operation and sent to the pitch system to execute shutdown.

2. A safe shutdown control method for an offshore floating wind turbine according to claim 1, characterized in that: In step 2), the additional pitch rate can generate additional thrust on the rotor side of the floating wind turbine, which is opposite to the pitch motion speed of the platform, thereby suppressing the pitch motion of the platform; The effective pitch angle of the platform is differentially calculated and then proportionally controlled to obtain the additional pitch rate. The specific formula is as follows: In the above formula, δ fa,1 represents the additional pitch rate of blade 1; δ fa,2 represents the additional pitch rate of blade 2; δ fa,3 A represents the additional pitch rate of blade 3; fa represents the pitch motion suppression proportional gain; θ fa,F Indicates the effective pitch angle of the platform; dθ fa,F / dt represents the rate of change of the effective pitch angle of the platform.

3. A safe shutdown control method for an offshore floating wind turbine according to claim 2, characterized in that: In step 2), the lateral additional pitch rate can generate lateral thrust on the rotor side of the floating wind turbine, which is opposite to the lateral movement speed of the platform, thereby suppressing the lateral movement of the platform; The platform's lateral effective inclination angle is subjected to differential calculation and then to proportional control, and then a sine function is introduced to obtain the lateral additional pitch rate. The specific formula is as follows: In the above formula, δ ss,1 represents the lateral additional pitch rate of blade 1; δ ss,2 represents the lateral additional pitch rate of blade 2; δ ss,3 A represents the lateral additional pitch rate of blade 3; ss represents the lateral motion suppression proportional gain; θ ss,F Indicates the effective lateral inclination angle of the platform; dθ ss,F / dt represents the rate of change of the platform's lateral effective tilt angle; represents the azimuth angle of blade 1; represents the azimuth angle of blade 2; represents the azimuth angle of blade 3; ω r Indicates the measured speed of the wind rotor; τ indicates the time delay of the pitch control system.

4. A safe shutdown control method for an offshore floating wind turbine according to claim 3, characterized in that: In step 3), the pitch additional pitch rate, the lateral additional pitch rate and the shutdown pitch rate of the three blades are respectively superimposed and integrated to obtain the final pitch command. The specific formula is as follows: In the above formula, β1 represents the blade 1 stop pitch angle command; β2 represents the blade 2 stop pitch angle command; β3 represents the blade 3 stop pitch angle command; δ fa,1 represents the additional pitch rate of blade 1; δ fa,2 represents the additional pitch rate of blade 2; δ fa,3 represents the additional pitch rate of blade 3; δ ss,1 represents the lateral additional pitch rate of blade 1; δ ss,2 represents the lateral additional pitch rate of blade 2; δ ss,3 represents the lateral additional pitch rate of blade 3; δ c,1 Indicates the blade 1 stop pitch rate output by the pitch controller; δ c,2 Indicates the blade 2 stop pitch rate output by the pitch controller; δ c,3 represents the blade 3 stop pitch rate output by the pitch controller; ∫dt represents the integral of time; β max Indicates the maximum pitch angle when the engine is stopped; min{} means comparing the two and taking the minimum value.

5. A safe shutdown control system for an offshore floating wind turbine, characterized in that: A safe shutdown control method for an offshore floating wind turbine generator system according to any one of claims 1 to 4, comprising: The platform inclination angle measurement module is used to collect the platform inclination angle of the floating wind turbine and perform data processing to obtain the platform pitch effective inclination angle and platform lateral effective inclination angle of the floating wind turbine; The pitch motion suppression module calculates the additional pitch rate based on the effective pitch angle of the platform of the floating wind turbine, which is used to suppress the pitch motion of the floating wind turbine during the shutdown process; The lateral motion suppression module calculates the lateral additional pitch rate based on the lateral effective inclination angle of the platform of the floating wind turbine, which is used to suppress the lateral motion of the floating wind turbine during the shutdown process; The pitch command superposition module is used to superimpose the pitch additional pitch rate, the lateral additional pitch rate and the shutdown pitch rate, obtain the final pitch command through integral operation and send it to the pitch system to execute shutdown.

6. A storage medium storing a program, characterized in that: When the program is executed by the processor, the safe shutdown control method of the offshore floating wind turbine set according to any one of claims 1 to 4 is implemented.

7. A computer device comprising a processor and a memory for storing a program executable by the processor, characterized in that: When the processor executes the program stored in the memory, the safe shutdown control method for the offshore floating wind turbine set according to any one of claims 1 to 4 is implemented.

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