External disturbances can induce torsional oscillation with weak damping in the shaft system of permanent magnet synchronous generators(PMSGs)based wind generation system,thereby inducing low-frequency oscillations.Ho...External disturbances can induce torsional oscillation with weak damping in the shaft system of permanent magnet synchronous generators(PMSGs)based wind generation system,thereby inducing low-frequency oscillations.However,the influence of electromagnetic torque on the shaft system damping and corresponding parameter laws have been scarcely explored.We define the electrical damping coefficient as a quantitative measure for the influence of electromagnetic torque on the shaft system damping.The torsional oscillation damping characteristics of the shaft system under vector control are analyzed,and the transfer function for electromagnetic torque and speed is derived.Additionally,we elucidate the mechanism by which the electromagnetic torque influences the shaft system damping.Simultaneously,laws describing the influence of wind speed,system parameters,and control parameters on the torsional oscillation damping are analyzed.Accordingly,the optimal damping angle of the shaft system a torsional oscillation suppression strategy is proposed to compensate for with uncertainty in the parameters affecting damping.The studied system is modeled using MATLAB/Simulink,and the simulation results validate the effectiveness of the theoretical analysis and proposed torsional oscillation suppression strategy.展开更多
The design of reliable controllers for wind energy conversion systems(WECSs)requires a dynamic model and accurate parameters of the wind generator.In this paper,a dynamic model and the parameter measurement and contro...The design of reliable controllers for wind energy conversion systems(WECSs)requires a dynamic model and accurate parameters of the wind generator.In this paper,a dynamic model and the parameter measurement and control of a direct-drive variable-speed WECS with a permanent magnet synchronous generator(PMSG)are presented.An experimental method is developed for measuring the key parameters of the PMSG.The measured parameters are used in the design of the controllers.The generator-side converter is controlled using a vector control scheme that maximizes the power extraction under varying wind speeds.A model predictive controller(MPC)is designed for the grid-side voltage source converter(VSC)to regulate the active and reactive power flows to the power grid by controlling the d-and q-axis currents in the synchronous reference frame.The MPC predicts the future values of the control variables and takes control actions based on the minimum value of the cost functions.To comply with the grid code requirement,a modified design approach for an LCL filter is presented and incorporated into the system.The design process is simple and incorporates significant filter parameters while avoiding iterative calculations.The comparative analysis of the designed filter with conventional L,LC,and iterative LCL filters demonstrates the effectiveness of the modified design approach.The proposed wind energy system with MPC and LCL filter is simulated in MATLAB/Simulink and experimentally implemented in the laboratory using the dSpace digital signal processor(DSP)system.The simulation and experimental results validate the efficacy of the designed controllers using the measured parameters and show dynamic and steady-state performance under varying wind speeds.展开更多
基金supported in part by the National Key R&D Program of China(No.2022YFE0105200)in part by State Grid Zhejiang Electric Power Company Science and Technology Program(No.5211JX230004).
文摘External disturbances can induce torsional oscillation with weak damping in the shaft system of permanent magnet synchronous generators(PMSGs)based wind generation system,thereby inducing low-frequency oscillations.However,the influence of electromagnetic torque on the shaft system damping and corresponding parameter laws have been scarcely explored.We define the electrical damping coefficient as a quantitative measure for the influence of electromagnetic torque on the shaft system damping.The torsional oscillation damping characteristics of the shaft system under vector control are analyzed,and the transfer function for electromagnetic torque and speed is derived.Additionally,we elucidate the mechanism by which the electromagnetic torque influences the shaft system damping.Simultaneously,laws describing the influence of wind speed,system parameters,and control parameters on the torsional oscillation damping are analyzed.Accordingly,the optimal damping angle of the shaft system a torsional oscillation suppression strategy is proposed to compensate for with uncertainty in the parameters affecting damping.The studied system is modeled using MATLAB/Simulink,and the simulation results validate the effectiveness of the theoretical analysis and proposed torsional oscillation suppression strategy.
文摘The design of reliable controllers for wind energy conversion systems(WECSs)requires a dynamic model and accurate parameters of the wind generator.In this paper,a dynamic model and the parameter measurement and control of a direct-drive variable-speed WECS with a permanent magnet synchronous generator(PMSG)are presented.An experimental method is developed for measuring the key parameters of the PMSG.The measured parameters are used in the design of the controllers.The generator-side converter is controlled using a vector control scheme that maximizes the power extraction under varying wind speeds.A model predictive controller(MPC)is designed for the grid-side voltage source converter(VSC)to regulate the active and reactive power flows to the power grid by controlling the d-and q-axis currents in the synchronous reference frame.The MPC predicts the future values of the control variables and takes control actions based on the minimum value of the cost functions.To comply with the grid code requirement,a modified design approach for an LCL filter is presented and incorporated into the system.The design process is simple and incorporates significant filter parameters while avoiding iterative calculations.The comparative analysis of the designed filter with conventional L,LC,and iterative LCL filters demonstrates the effectiveness of the modified design approach.The proposed wind energy system with MPC and LCL filter is simulated in MATLAB/Simulink and experimentally implemented in the laboratory using the dSpace digital signal processor(DSP)system.The simulation and experimental results validate the efficacy of the designed controllers using the measured parameters and show dynamic and steady-state performance under varying wind speeds.
