The asymmetric or periodically varying blade loads resulted by wind shear become more significant as the blade length is increased to capture more wind power.Additionally,compared with the onshore wind turbines,their ...The asymmetric or periodically varying blade loads resulted by wind shear become more significant as the blade length is increased to capture more wind power.Additionally,compared with the onshore wind turbines,their offshore counterparts are subjected to additional wave loadings in addition to wind loadings within their lifetime.Therefore,vibration control and fatigue load mitigation are crucial for safe operation of large-scale offshore wind turbines.In view of this,a multi-body model of an offshore bottom-fixed wind turbine including a detailed drivetrain is established in this paper.Then,an individual pitch controller(IPC)is designed using disturbance accommodating control.State feedback is used to add damping in flexible modes of concern,and a state estimator is designed to predict unmeasured signals.Continued,a coupled aero-hydro-servo-elastic model is constructed.Based on this coupled model,the load reduction effect of IPC and the dynamic responses of the drivetrain are investigated.The results showed that the designed IPC can effectively reduce the structural loads of the wind turbine while stabilizing the turbine power out-put.Moreover,it is found that the drivetrain dynamic responses are improved under IPC.展开更多
Collective pitch control and individual pitch control algorithms were present for straight-bladed vertical axis wind turbine to improve the self-starting capacity.Comparative analysis of straight-bladed vertical axis ...Collective pitch control and individual pitch control algorithms were present for straight-bladed vertical axis wind turbine to improve the self-starting capacity.Comparative analysis of straight-bladed vertical axis wind turbine(SB-VAWT) with or without pitch control was conducted from the aspects of aerodynamic force,flow structure and power coefficient.The computational fluid dynamics(CFD) prediction results show a significant increase in power coefficient for SB-VAWT with pitch control.According to the aerodynamic forces and total torque coefficient obtained at various tip speed ratios(TSRs),the results indicate that the blade pitch method can increase the power output and decrease the deformation of blade;especially,the total torque coefficient of blade pitch control at TSR 1.5 is about 2.5 times larger than that of fixed pitch case.Furthermore,experiment was carried out to verify the feasibility of pitch control methods.The results show that the present collective pitch control and individual pitch control methods can improve the self-starting capacity of SB-VAWT,and the former is much better and its proper operating TSRs ranges from 0.4 to 0.6.展开更多
Wind turbines undergo degradation due to various factors which induce stress, thereby leading to fatigue damage to various wind turbine components. In addition, the current increase in demand for electrical power has ...Wind turbines undergo degradation due to various factors which induce stress, thereby leading to fatigue damage to various wind turbine components. In addition, the current increase in demand for electrical power has led to the development of large wind turbines, which result in increased structural loads, therefore, increasing the possibility of early failure due to fatigue load. This paper proposes a proportional integral observer (PI-Observer) based disturbance accommodation controller (DAC) with individual pitch control (IPC) for load mitigation to reduce components’ damage and ensure the wind turbine is operational for the expected lifetime. The results indicate a reduction in blades’ bending moments with a standard deviation of 15.9%, which positively impacts several other wind turbine subsystems. Therefore, the lifetime control strategy demonstrates effective structural load mitigation without compromise on power generation, thus, achieving a nominal lifetime control to inhibit premature failure.展开更多
基金This paper is financially supported by the Scientific Research Foundation of Chongqing University of Technology(Grant Nos.2020ZDZ023 and 2019ZD124)the Project of Science and Technology Research Program of Chongqing Education Commission of China(Grant No.KJQN202101133)the National Natural Science Foundation Cultivation Program of Chongqing University of Technology(Grant No.2021PYZ14).
文摘The asymmetric or periodically varying blade loads resulted by wind shear become more significant as the blade length is increased to capture more wind power.Additionally,compared with the onshore wind turbines,their offshore counterparts are subjected to additional wave loadings in addition to wind loadings within their lifetime.Therefore,vibration control and fatigue load mitigation are crucial for safe operation of large-scale offshore wind turbines.In view of this,a multi-body model of an offshore bottom-fixed wind turbine including a detailed drivetrain is established in this paper.Then,an individual pitch controller(IPC)is designed using disturbance accommodating control.State feedback is used to add damping in flexible modes of concern,and a state estimator is designed to predict unmeasured signals.Continued,a coupled aero-hydro-servo-elastic model is constructed.Based on this coupled model,the load reduction effect of IPC and the dynamic responses of the drivetrain are investigated.The results showed that the designed IPC can effectively reduce the structural loads of the wind turbine while stabilizing the turbine power out-put.Moreover,it is found that the drivetrain dynamic responses are improved under IPC.
基金Project (E201216) supported by Heilongjiang Provincial Natural Science Foundation,China
文摘Collective pitch control and individual pitch control algorithms were present for straight-bladed vertical axis wind turbine to improve the self-starting capacity.Comparative analysis of straight-bladed vertical axis wind turbine(SB-VAWT) with or without pitch control was conducted from the aspects of aerodynamic force,flow structure and power coefficient.The computational fluid dynamics(CFD) prediction results show a significant increase in power coefficient for SB-VAWT with pitch control.According to the aerodynamic forces and total torque coefficient obtained at various tip speed ratios(TSRs),the results indicate that the blade pitch method can increase the power output and decrease the deformation of blade;especially,the total torque coefficient of blade pitch control at TSR 1.5 is about 2.5 times larger than that of fixed pitch case.Furthermore,experiment was carried out to verify the feasibility of pitch control methods.The results show that the present collective pitch control and individual pitch control methods can improve the self-starting capacity of SB-VAWT,and the former is much better and its proper operating TSRs ranges from 0.4 to 0.6.
文摘Wind turbines undergo degradation due to various factors which induce stress, thereby leading to fatigue damage to various wind turbine components. In addition, the current increase in demand for electrical power has led to the development of large wind turbines, which result in increased structural loads, therefore, increasing the possibility of early failure due to fatigue load. This paper proposes a proportional integral observer (PI-Observer) based disturbance accommodation controller (DAC) with individual pitch control (IPC) for load mitigation to reduce components’ damage and ensure the wind turbine is operational for the expected lifetime. The results indicate a reduction in blades’ bending moments with a standard deviation of 15.9%, which positively impacts several other wind turbine subsystems. Therefore, the lifetime control strategy demonstrates effective structural load mitigation without compromise on power generation, thus, achieving a nominal lifetime control to inhibit premature failure.
