| At present,energy development of the world will be from fossil fuel to low carbon energy system.The era of renewable energy has become the ultimate goal of energy transformation.Thus,wind energy has become one of the hottest clean energy sources.With the rapid development of wind power industry,variable pitch wind turbine have become the most widely used wind turbines.The function of the pitch system is to change the pitch angle of the blade and make the wind energy utilization and output power as high as possible.Due to the frequent faults of hydraulic pitch system,the most reasonable and effective solution must be chosen,otherwise catastrophic accidents will occur.Therefore,the research on fault diagnosis of pitch control system is of great significance to the long-term stable operation of wind turbines and the reduction of operation cost of wind turbines.Firstly,through the simplification of the complex wind turbine,the system mathematical model is established for each key component of the wind turbine.Then the multi-innovation identification algorithm is used to identify the parameters of the system.By the analysis and comparison of the parameters,the fault of the hydraulic pitch system is judged.Aiming at the fault diagnosis problem of wind turbine pitch system affected by state-delay,firstly,the complex system is transformed into state space model,and the system identification model is established.At the same time,the fault model of pitch actuator is established,and the parameters of wind turbine pitch system with state-delay are estimated.Using the multi-innovation algorithm fault diagnosis method in the paper,considering the state-delay of the wind turbine pitch system model,the simulation program is written in MATLAB to verify the effectiveness of the diagnosis method.In order to diagnosis state and parameter estimation faults of state space systems with two state-delays,a multi-innovation identification algorithm is proposed by using dimension expansion method.For this complicated double state-delays system,the idea of state and parameter interactive estimation is used to form a joint estimation method of state and parameter.The parameter estimation error is introduced and the relationship between the norm of system parameter difference and parameter estimation error is used to judge whether there is a fault.The wind turbine benchmark model is used to simulate the system to verify the effectiveness of the fault diagnosis method. |
