基于On-off和H_∞状态反馈的风能转换系统的双频环优化控制

Two-frequency-loop optimal control for wind energy conversion system based on on-off and H_∞ state feedback

根据风速的多时间尺度特性,在风能转换系统非线性机理模型的基础上,基于频率分离原理建立风能转换系统的双频环模型.在优化控制理论指导下,以额定风速以下的风能最大捕获为目标,针对低频环模型和高频环模型分别设计优化控制器,其中低频环采用On-off稳态优化控制方法,高频环采用H∞状态反馈优化控制方法,从而建立了风能转换系统的双频环优化控制结构.仿真结果表明:基于On-off和H∞状态反馈的风能转换系统的双频环优化控制方法是有效的,且相对于单纯的On-off控制具有更高的控制精度和更好的鲁棒性能,可以实现在额定风速以下的风能捕获功率最大化.

According to the multi-time scale of wind speed,a two-frequency model is established for wind energy conversion system(WECS) based on the nonlinear mechanical model and the frequency separation principle.Under the guidance of optimal control theory,the maximum captured wind energy below the rated wind speed is taken as control objective,then the low and high frequency optimal controllers are designed.On-off optimal control is used in the low-frequency loop,while H∞ state feedback optimal control is introduced in the high-frequency loop.Thus,the optimal control structure for WECS is established.Simulation results demonstrate the feasibility of the proposed two-frequency-loop optimal control,and moreover,it has much better robustness and control accuracy than on-off control.The generator can be controlled to maximize the efficiency of captured wind energy below the rated wind speed.