风能转换系统双频环滑模控制

为了实现额定风速以下风能转换系统风能捕获率的最大化,根据风速的多时间尺度特性,基于频率分离原理建立风能转换系统的双频环模型.在最优控制理论的指导下,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PI控制;高频环采用加权积分型增益滑模控制.仿真结果表明,采用基于滑模控制的风能转换系统双频环优化控制方法,风能捕获率和叶尖速比相对于单纯的PI控制具有更好的控制效果,且当系统稳定运行时,风能捕获率可以保持在最优值0.475附近,叶尖速比也可以维持在最优值7 附近,可以实现额定风速以下的风能捕获率最大化.

Two-frequency-loop control for wind energy conversion system based on sliding-mode control

In order to maximize the wind energy capture ratio below the rated wind speed,a two-frequency model was established for wind energy conversion system (WECS) based on multi-time-scale of wind speed and the frequency separation principle. The low and high frequency optimal controllers were designed using optimal control theory. PI optimal control was used in the low-frequency-loop,while the sliding-mode control with weighed integral gain was introduced in the high-frequency-loop. The simulation results indicate that the wind energy capture ratio and the tip speed ratio comparing with the PI control are improved by the proposed control method. Moreover,once the system is in steady-state regime,the wind energy capture ratio can be maintained around its optimal value (0.475) and the tip speed ratio around its optimal value (7) ,So it is feasible to maximize the wind energy capture ratio below the rated wind speed.