Coupling simulation calculation method and system for floating offshore wind turbine

Abstract

The application discloses a kind of coupling synergic simulation calculation method and system of floating offshore wind turbine, and the application relates to wind power generation technical field, comprising the following steps: fatigue damage characteristic parameter of drive chain and mooring chain is collected in real time, the current cumulative damage value of each other is calculated;The damage ratio of both is calculated and compared with preset equalization threshold interval, the difference of damage speed is judged;If damage ratio is higher than upper limit, generator torque and variable pitch angle are optimized according to environmental wind speed;If lower than lower limit, then additional compensation quantity proportional to platform pitch speed is attached to variable pitch controller, and the remaining life is predicted according to greater cumulative damage value and its change trend, and maintenance warning is sent when any cumulative damage reaches failure threshold;The method effectively improves the operation safety and maintenance efficiency of wind turbine.

Claims

1. A coupled co-simulation calculation method for a floating offshore wind turbine, characterized in that, The specific steps include: Step 1: Collect fatigue damage characteristic parameters of the drive chain and mooring chain of the floating offshore wind turbine in real time, and calculate the current cumulative damage value of the drive chain and the current cumulative damage value of the mooring chain respectively. Step 2: Calculate the ratio of the current cumulative damage value of the drive chain to the current cumulative damage value of the mooring chain to obtain the damage ratio used to characterize the degree of imbalance in the life consumption of the two subsystems, and compare the damage ratio with a preset balance threshold range. Step 3: If the damage ratio is higher than the upper limit of the equilibrium threshold range, it is determined that the damage speed of the drive chain is greater than that of the mooring chain. At this time, the first optimization logic is executed, which specifically includes determining the optimization object based on the ambient wind speed. The optimization object includes the generator torque and the independent pitch angle. The optimization object is adjusted until the damage ratio falls back to the equilibrium threshold range. Step 4: If the damage ratio is lower than the lower limit of the equilibrium threshold range, it is determined that the damage speed of the mooring chain is greater than that of the drive chain. At this time, the second optimization logic is executed, which is to add a pitch angle compensation amount proportional to the platform pitch speed to the pitch controller of the wind turbine until the damage ratio rises back to the equilibrium threshold range. Step 5: Based on the larger of the current cumulative damage values ​​of the drive chain and mooring chain, and the trend of the cumulative damage value, predict the cooperative remaining life of the floating offshore wind turbine, and issue a maintenance warning when either cumulative damage value reaches a preset failure threshold.

2. The coupled co-simulation calculation method for a floating offshore wind turbine according to claim 1, characterized in that: The fatigue damage characteristic parameters of the transmission chain specifically include the main shaft torque and effective value of high-frequency vibration of the floating offshore wind turbine, and the fatigue damage characteristic parameters of the mooring chain include the dynamic tension value and tension change rate of the mooring chain. The logic for calculating the current cumulative damage value of the drive train and mooring chain is as follows: Based on the reference fatigue damage characteristic parameters, the instantaneous damage increment at the current moment is calculated. The Miner linear accumulation algorithm is used to determine the current cumulative damage value of the drive train and mooring chain based on the instantaneous damage increment, which is specifically expressed as the sum of the instantaneous damage increment at the current moment and the cumulative damage value at the previous moment.

3. The coupled co-simulation calculation method for a floating offshore wind turbine according to claim 2, characterized in that, The specific method for calculating the instantaneous damage increment of the transmission chain at the current moment is as follows: For the current moment, calculate the ratio of the main shaft torque of the transmission chain to the reference fatigue torque of the transmission chain. Use this ratio as the base and the torque damage index as the exponent. Use the quotient of the calculated value and the reference cycle number of the transmission chain as the first damage increment. Calculate the ratio of the effective value of high-frequency vibration of the transmission chain to the reference fatigue value of high-frequency vibration of the transmission chain. Use this ratio as the base and the vibration damage index as the exponent. Use the quotient of the calculated value and the reference number of vibration cycles of the transmission chain as the second damage increment. The sum of the first damage increment and the second damage increment is taken as the instantaneous damage increment of the transmission chain at the current moment. The specific method for calculating the instantaneous damage increment of the mooring chain at the current moment is as follows: Obtain the dynamic tension value of the mooring chain at the current moment, and determine the tension change rate of the mooring chain at the current moment based on the dynamic tension value of the mooring chain at the current moment. Take the absolute value of the tension change rate, calculate the ratio of the absolute value of the tension change rate to the reference tension change rate, use this ratio as the base, use the tension change rate damage index as the exponent, and use the quotient of the calculated value and the number of cycles with the mooring chain as the reference as the first damage item. Calculate the ratio of the dynamic tension value of the mooring chain at the current moment to the reference average tension, use this ratio as the base and the tension change rate damage index as the exponent, and calculate the second damage term. The product of the first damage term and the second damage term is used as the instantaneous damage increment of the mooring chain at the current moment.

4. The coupled co-simulation calculation method for a floating offshore wind turbine according to claim 3, characterized in that, The damage ratio is specifically expressed as follows: Preset a non-negative positive number, use the sum of the number and the current cumulative damage value of the mooring chain as the denominator, and use the current cumulative damage value of the drive chain as the numerator. The resulting ratio is the damage ratio. If the damage ratio falls within the preset equilibrium threshold range, the current control strategy of the wind turbine will remain unchanged, and it will operate in rated power tracking mode. If the instantaneous damage increment of the mooring chain at the current moment is not less than the preset damage increment, and the instantaneous damage increment of the drive chain at the current moment is less than the preset damage increment threshold, then the second optimization logic is executed based on the instantaneous damage increment of the mooring chain at the current moment. If the instantaneous damage increment of the drive chain at the current moment is not less than the preset damage increment threshold, and the instantaneous damage increment of the mooring chain at the current moment is less than the preset damage increment threshold, then the first optimization logic is executed based on the instantaneous damage increment of the drive chain at the current moment. If the instantaneous damage increment of both the drive chain and the mooring chain is less than the preset damage increment threshold, or is not less than the preset damage increment threshold, then the optimization logic to be executed is determined based on the damage ratio.

5. The coupled co-simulation calculation method for a floating offshore wind turbine according to claim 4, characterized in that, The specific logic upon which the first optimization logic is based is as follows: The ambient wind speed within a preset time window measured by the cabin anemometer is retrieved. The end point of the preset time window is specifically set as follows: the average wind speed within the preset time window is calculated based on the current time, and the optimization target is determined based on the average wind speed. If the average wind speed within the preset time window is not greater than the preset rated wind speed, the upper limit of the generator torque will be gradually reduced, and the reduction step size will be proportional to the degree to which the current damage ratio exceeds the upper limit. If the average wind speed within the preset time window is greater than the preset rated wind speed, the flapping moment at the root of any wind turbine blade is collected, and an independent pitch component is added to the wind turbine blade based on the flapping moment.

6. The coupled co-simulation calculation method for a floating offshore wind turbine according to claim 5, characterized in that, The calculation of the reduction step size is specifically expressed as follows: calculate the difference between the current damage ratio and the upper limit of the equilibrium threshold interval, and use the product of this difference, the rated torque of the generator and the first proportional coefficient as the first candidate step size; If the first optimization logic is executed based on the instantaneous damage increment of the transmission chain at the current moment, the difference between the instantaneous damage increment of the transmission chain at the current moment and the damage increment threshold is calculated, and the product of this difference, the rated torque of the generator and the first proportional coefficient is used as the first candidate step size. The product of the second proportional coefficient and the rated torque of the generator is used as the second candidate step size, and the second proportional coefficient is not less than the first proportional coefficient. The minimum value between the first candidate step size and the second candidate step size is selected as the reduction step size; The generator torque upper limit is gradually reduced by decreasing the step size. Specifically, based on the set sampling interval, the difference between the generator torque upper limit and the decreasing step size is used as the new generator torque upper limit at each sampling time, and the damage ratio at the next sampling time is monitored. The calculation of the independent pitch components specifically includes: For any blade, based on its mechanical structure, determine the maximum additional angle to be applied, obtain the flapping moment at the root of the blade, and normalize the flapping moment at the root of the blade by the average value of the bending moments of all blades of the current wind turbine to obtain the first additional term; Calculate the difference between the current damage ratio and the upper limit of the equilibrium threshold range, and calculate the ratio of this difference to the preset offset constant. Select the minimum value between the constant 1 and this ratio as the second additional item. If the first optimization logic is executed based on the instantaneous damage increment of the transmission chain at the current moment, the difference between the instantaneous damage increment of the transmission chain at the current moment and the damage increment threshold is calculated, the ratio of the difference to the preset offset constant is calculated, and the minimum value between the constant 1 and the ratio is selected as the second additional item. The product of the maximum additional angle, the first additional term, and the second additional term is taken as the independent pitch component added to the blade. The damage ratio is recalculated at each sampling time. If the damage ratio falls within the equilibrium threshold range for three consecutive sampling times, the upper limit of generator torque is gradually restored or the additional independent pitch component is reduced to 0.

7. The coupled co-simulation calculation method for a floating offshore wind turbine according to claim 6, characterized in that, The specific logic underlying the execution of the second optimization logic is as follows: extract the platform pitch angle of the floating offshore wind turbine at the current moment, calculate the instantaneous dominant frequency through short-time Fourier transform, compare the instantaneous dominant frequency with the platform pitch natural frequency, and if the absolute difference between the instantaneous dominant frequency and the platform pitch natural frequency is not greater than the preset resonance frequency threshold, then it is determined that the current state is resonance, and in-phase compensation is performed. Otherwise, it is determined to be a non-resonance state, and phase lag compensation is performed; For in-frequency and in-phase compensation, the calculation of the pitch angle compensation specifically includes: Obtain the platform's maximum pitch angle, take the absolute value of the current platform's pitch angular velocity, and use the ratio of this absolute value to the reference pitch angular velocity as the first compensation term; Calculate the difference between the lower limit of the equilibrium threshold interval and the current damage ratio, and use the ratio of this difference to the preset offset constant as the second compensation term; If the second optimization logic is executed based on the instantaneous damage increment of the mooring chain at the current moment, the difference between the instantaneous damage increment of the mooring chain at the current moment and the damage increment threshold is calculated, and the ratio of the difference to the preset offset constant is used as the second compensation term. The product of the maximum pitch angle, the first compensation term, and the second compensation term is used as the current pitch angle compensation amount for in-frequency and in-phase compensation. For phase lag compensation, the calculation of the pitch angle compensation specifically includes: Extract the current platform pitch angle and use the ratio of the platform pitch angle to the reference pitch angle as the third compensation term; The product of the maximum pitch angle, the third compensation term, and the second compensation term is used as the current pitch angle compensation amount for phase lag compensation.

8. The coupled co-simulation calculation method for a floating offshore wind turbine according to claim 7, characterized in that, The logic underlying the prediction of the cooperative remaining life of a floating offshore wind turbine is as follows: The larger of the cumulative damage value of the drivetrain and the cumulative damage value of the mooring chain is taken as the current dominant damage. For this current dominant damage, the average increment of the current dominant damage is obtained. Based on the current dominant damage, the average increment of the current dominant damage, and the rate of change of the damage ratio, the cooperative remaining life is predicted, specifically expressed as follows: If the current damage ratio is higher than the upper limit of the equilibrium threshold range, calculate the difference between the preset failure threshold and the current dominant damage, and calculate the ratio of this difference to the average increment of the current dominant damage, as the first collaborative life term. Calculate the product of the preset adjustment ratio constant and the maximum value between the damage ratio change rate and the constant 0, and use the difference between this product and the constant 1 as the second synergistic life term; The product of the first and second collaborative lifetime terms is used as the predicted collaborative remaining lifetime of the floating offshore wind turbine. If the current damage ratio is lower than the lower limit of the equilibrium threshold range, calculate the product of the preset adjustment ratio constant and the minimum value between the damage ratio change rate and the constant 0, and use the sum of this product and the constant 1 as the second collaborative life term; The product of the first and second collaborative lifetime terms is used as the predicted collaborative remaining lifetime of the floating offshore wind turbine.

9. A coupled co-simulation calculation system for a floating offshore wind turbine, used to execute the coupled co-simulation calculation method for a floating offshore wind turbine as described in any one of claims 1-8, characterized in that, include: The data acquisition module is used to collect fatigue damage characteristic parameters of the drive chain and mooring chain of the floating offshore wind turbine in real time, and calculate the current cumulative damage value of the drive chain and the current cumulative damage value of the mooring chain, respectively. The damage comparison module is used to calculate the ratio of the current cumulative damage value of the drive chain to the current cumulative damage value of the mooring chain, to obtain a damage ratio that characterizes the degree of imbalance in the life consumption of the two subsystems, and to compare the damage ratio with a preset balance threshold range. The drive chain adjustment module is used to determine that the damage rate of the drive chain is greater than that of the mooring chain if the damage ratio is higher than the upper limit of the equilibrium threshold range. At this time, the first optimization logic is executed, which specifically includes determining the optimization object based on the ambient wind speed. The optimization object includes the generator torque and the independent pitch angle. The optimization object is adjusted until the damage ratio falls back to the equilibrium threshold range. The mooring chain adjustment module is used to determine that the damage speed of the mooring chain is greater than that of the drive chain if the damage ratio is lower than the lower limit of the equilibrium threshold range. At this time, the second optimization logic is executed, specifically, an additional pitch angle compensation amount proportional to the platform pitch speed is added to the pitch controller until the damage ratio rises back to the equilibrium threshold range. The life prediction module is used to predict the cooperative remaining life of the floating offshore wind turbine based on the larger of the current cumulative damage values ​​of the drive chain and the mooring chain, as well as the trend of the cumulative damage values, and to issue a maintenance warning when either cumulative damage value reaches a preset failure threshold.

Images