Na Wang - Academia.edu (original) (raw)

Papers by Na Wang

2016 American Control Conference (ACC), 2016

Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) alg... more Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) algorithm are designed for the three-bladed Controls Advanced Research Turbine to regulate rotor speed and to mitigate blade root flapwise bending loads in above-rated wind speed. One of the DAC-based IPCs is designed based on a transformed symmetrical-asymmetrical (TSA) turbine model, with wind disturbances being modeled as a collective horizontal component and an asymmetrical linear shear component. Another DACbased IPC is designed based on a multiblade coordinate (MBC) transformed turbine model, with a horizontal component and a vertical shear component being modeled as step waveform disturbance. Both of the DAC-based IPCs are found via a regulation equation solved by Kronecker product. Actuator dynamics are considered in the design processes to compensate for actuator phase delay. The simulation study shows the effectiveness of the proposed DAC-based IPCs compared to a proportional-integral (PI) collective pitch controller (CPC). Improvement on rotor speed regulation and once-per-revolution and twice-per-revolution load reductions has been observed in the proposed IPC designs. NOMENCLATURE v 1,2,3 Wind speeds at blade 1,2,3. β 1,2,3 Blade 1,2,3 pitch angles. Ω Rotor speed. x,x State vector and transformed state vector. F, Θ Wind disturbance model matrices. A, B, B v , C, D, D v Turbine state space model matrices. T m , T β , T v , T y Linear transformation matrices. T mbc MBC transformation matrix. G x , G v DAC controller gains.

Journal of Dynamic Systems, Measurement, and Control, 2017

In this paper, solvability conditions for disturbance accommodating control (DAC) have been discu... more In this paper, solvability conditions for disturbance accommodating control (DAC) have been discussed and applied on wind turbine controller design in above-rated wind speed to regulate rotor speed and to mitigate turbine structural loads. An asymptotically stabilizing DAC controller with disturbance impact on the wind turbine being totally canceled out can be found if certain conditions are fulfilled. Designing a rotor speed regulation controller without steady-state error is important for applying linear control methodology such as DAC on wind turbines. Therefore, solvability conditions of DAC without steady-state error are attractive and can be taken as examples when designing a multitask turbine controller. DAC controllers solved via Moore–Penrose Pseudoinverse and the Kronecker product are discussed, and solvability conditions of using them are given. Additionally, a new solvability condition based on inverting the feed-through D term is proposed for the sake of reducing comput...

In this paper, solvability conditions for disturbance accommodating control (DAC) have been discu... more In this paper, solvability conditions for disturbance accommodating control (DAC) have been discussed and applied on wind turbine controller design in above-rated wind speed to regulate rotor speed and to mitigate turbine structural loads. An asymptotically stabilizing DAC controller with disturbance impact on the wind turbine being totally canceled out can be found if certain conditions are fulfilled. Designing a rotor speed regulation controller without steady-state error is important for applying linear control methodology such as DAC on wind turbines. Therefore, solvability conditions of DAC without steady-state error are attractive and can be taken as examples when designing a multitask turbine controller. DAC controllers solved via Moore-Penrose Pseudoinverse and the Kronecker product are discussed, and solvability conditions of using them are given. Additionally, a new solvability condition based on inverting the feed-through D term is proposed for the sake of reducing computational burden in the Kronecker product. Applications of designing collective pitch and independent pitch controllers based on DAC are presented. Recommendations of designing a DAC-based wind turbine controller are given. A DAC controller motivated by the proposed solvability condition that utilizes the inverse of feed-through D term is developed to mitigate the blade flapwise once-per-revolution bending moment together with a standard proportional integral controller in the control loop to assist rotor speed regulation. Simulation studies verify the discussed solvability conditions of DAC and show the effectiveness of the proposed DAC control design methodology. 1 Introduction Disturbance accommodating control (DAC) enables dynamic modeling of uncertain disturbances that act on the system and synthesizes both the feedback and feedforward controllers to minimize the effects of such disturbances on the system output [1]. The unknown persistent disturbances will drastically reduce the benefits of active structure control unless the controller can be designed to counteract such disturbances [2, 3]. A predefined waveform generator as the internal model is incorporated to the system state-space model, and the DAC design algorithms automatically produce integral or notch-filter controllers for the assumed disturbance rejection. The multivariable state-space optimal control strategies can be extended in the DAC to get an asymptotically stable feedback controller and a feedforward controller resolved by the DAC algorithms and are able to accommodate multivariable disturbances. Such control structure requires an observer in the control loop to estimate the unmeasured turbine and disturbance states.

2016 American Control Conference (ACC), 2016

Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) alg... more Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) algorithm are designed for the three-bladed Controls Advanced Research Turbine to regulate rotor speed and to mitigate blade root flapwise bending loads in above-rated wind speed. One of the DAC-based IPCs is designed based on a transformed symmetrical-asymmetrical (TSA) turbine model, with wind disturbances being modeled as a collective horizontal component and an asymmetrical linear shear component. Another DACbased IPC is designed based on a multiblade coordinate (MBC) transformed turbine model, with a horizontal component and a vertical shear component being modeled as step waveform disturbance. Both of the DAC-based IPCs are found via a regulation equation solved by Kronecker product. Actuator dynamics are considered in the design processes to compensate for actuator phase delay. The simulation study shows the effectiveness of the proposed DAC-based IPCs compared to a proportional-integral (PI) collective pitch controller (CPC). Improvement on rotor speed regulation and once-per-revolution and twice-per-revolution load reductions has been observed in the proposed IPC designs. NOMENCLATURE v 1,2,3 Wind speeds at blade 1,2,3. β 1,2,3 Blade 1,2,3 pitch angles. Ω Rotor speed. x,x State vector and transformed state vector. F, Θ Wind disturbance model matrices. A, B, B v , C, D, D v Turbine state space model matrices. T m , T β , T v , T y Linear transformation matrices. T mbc MBC transformation matrix. G x , G v DAC controller gains.

Journal of Dynamic Systems, Measurement, and Control, 2017

In this paper, solvability conditions for disturbance accommodating control (DAC) have been discu... more In this paper, solvability conditions for disturbance accommodating control (DAC) have been discussed and applied on wind turbine controller design in above-rated wind speed to regulate rotor speed and to mitigate turbine structural loads. An asymptotically stabilizing DAC controller with disturbance impact on the wind turbine being totally canceled out can be found if certain conditions are fulfilled. Designing a rotor speed regulation controller without steady-state error is important for applying linear control methodology such as DAC on wind turbines. Therefore, solvability conditions of DAC without steady-state error are attractive and can be taken as examples when designing a multitask turbine controller. DAC controllers solved via Moore–Penrose Pseudoinverse and the Kronecker product are discussed, and solvability conditions of using them are given. Additionally, a new solvability condition based on inverting the feed-through D term is proposed for the sake of reducing comput...

In this paper, solvability conditions for disturbance accommodating control (DAC) have been discu... more In this paper, solvability conditions for disturbance accommodating control (DAC) have been discussed and applied on wind turbine controller design in above-rated wind speed to regulate rotor speed and to mitigate turbine structural loads. An asymptotically stabilizing DAC controller with disturbance impact on the wind turbine being totally canceled out can be found if certain conditions are fulfilled. Designing a rotor speed regulation controller without steady-state error is important for applying linear control methodology such as DAC on wind turbines. Therefore, solvability conditions of DAC without steady-state error are attractive and can be taken as examples when designing a multitask turbine controller. DAC controllers solved via Moore-Penrose Pseudoinverse and the Kronecker product are discussed, and solvability conditions of using them are given. Additionally, a new solvability condition based on inverting the feed-through D term is proposed for the sake of reducing computational burden in the Kronecker product. Applications of designing collective pitch and independent pitch controllers based on DAC are presented. Recommendations of designing a DAC-based wind turbine controller are given. A DAC controller motivated by the proposed solvability condition that utilizes the inverse of feed-through D term is developed to mitigate the blade flapwise once-per-revolution bending moment together with a standard proportional integral controller in the control loop to assist rotor speed regulation. Simulation studies verify the discussed solvability conditions of DAC and show the effectiveness of the proposed DAC control design methodology. 1 Introduction Disturbance accommodating control (DAC) enables dynamic modeling of uncertain disturbances that act on the system and synthesizes both the feedback and feedforward controllers to minimize the effects of such disturbances on the system output [1]. The unknown persistent disturbances will drastically reduce the benefits of active structure control unless the controller can be designed to counteract such disturbances [2, 3]. A predefined waveform generator as the internal model is incorporated to the system state-space model, and the DAC design algorithms automatically produce integral or notch-filter controllers for the assumed disturbance rejection. The multivariable state-space optimal control strategies can be extended in the DAC to get an asymptotically stable feedback controller and a feedforward controller resolved by the DAC algorithms and are able to accommodate multivariable disturbances. Such control structure requires an observer in the control loop to estimate the unmeasured turbine and disturbance states.