An extension of L_1 adaptive control is proposed for the unmatched uncertain nonlinear system with the nonlinear reference system that defines the performance specifications. The control law adapts fast and tracks the...An extension of L_1 adaptive control is proposed for the unmatched uncertain nonlinear system with the nonlinear reference system that defines the performance specifications. The control law adapts fast and tracks the reference system with the guaranteed robustness and transient performance in the presence of unmatched uncertainties. The interval analysis is used to build the quasi-linear parameter-varying model of unmatched nonlinear system, and the robust stability of the proposed controller is addressed by sum of squares programming. The transient performance analysis shows that within the limit of hardware a large adaption gain can improve the asymptotic tracking performance. Simulation results are provided to demonstrate the theoretical findings of the proposed controller.展开更多
PV （photovoltaic） systems need MPPT （maximum power point tracking） techniques to hamess maximum power from PV arrays. P＆O （perturb ＆ observe）, and incremental conductance methods are two basic MPPT algorithms ...PV （photovoltaic） systems need MPPT （maximum power point tracking） techniques to hamess maximum power from PV arrays. P＆O （perturb ＆ observe）, and incremental conductance methods are two basic MPPT algorithms applied to PV systems with fixed and variable step sizes. However, the existing variable step MPPT method exhibits complications which occur in the algorithm due to sudden, large irradiance changes which result in dips in power extraction. This paper proposes a modification to the existing variable step MPPT method to avoid such complications and hence improve the tracking accuracy under irradiance transients. The proposed technique is experimentally verified under sudden irradiance disturbances using a solar array. The results are compared with the existing variable step method. The superiority of the proposed technique is demonstrated through a laboratory prototype.展开更多
In this paper, based on the analysis of the mathematical model in a common synchronous reference frame of the brushless doubly-fed generator （BDFG）, the grid connection strategy and maximum energy extraction control...In this paper, based on the analysis of the mathematical model in a common synchronous reference frame of the brushless doubly-fed generator （BDFG）, the grid connection strategy and maximum energy extraction control were both analyzed. Besides, the transient simula- tion of no-load model and generation model of the BDFG have been developed on the MATLAB/Simulink platform. The test results during cutting-in grid confirmed the good dynamic performance of grid synchronization and effective power control approach for the BDFG-based variable speed wind turbines.展开更多
文摘An extension of L_1 adaptive control is proposed for the unmatched uncertain nonlinear system with the nonlinear reference system that defines the performance specifications. The control law adapts fast and tracks the reference system with the guaranteed robustness and transient performance in the presence of unmatched uncertainties. The interval analysis is used to build the quasi-linear parameter-varying model of unmatched nonlinear system, and the robust stability of the proposed controller is addressed by sum of squares programming. The transient performance analysis shows that within the limit of hardware a large adaption gain can improve the asymptotic tracking performance. Simulation results are provided to demonstrate the theoretical findings of the proposed controller.
文摘PV （photovoltaic） systems need MPPT （maximum power point tracking） techniques to hamess maximum power from PV arrays. P＆O （perturb ＆ observe）, and incremental conductance methods are two basic MPPT algorithms applied to PV systems with fixed and variable step sizes. However, the existing variable step MPPT method exhibits complications which occur in the algorithm due to sudden, large irradiance changes which result in dips in power extraction. This paper proposes a modification to the existing variable step MPPT method to avoid such complications and hence improve the tracking accuracy under irradiance transients. The proposed technique is experimentally verified under sudden irradiance disturbances using a solar array. The results are compared with the existing variable step method. The superiority of the proposed technique is demonstrated through a laboratory prototype.
文摘In this paper, based on the analysis of the mathematical model in a common synchronous reference frame of the brushless doubly-fed generator （BDFG）, the grid connection strategy and maximum energy extraction control were both analyzed. Besides, the transient simula- tion of no-load model and generation model of the BDFG have been developed on the MATLAB/Simulink platform. The test results during cutting-in grid confirmed the good dynamic performance of grid synchronization and effective power control approach for the BDFG-based variable speed wind turbines.
