变速恒频双馈风力发电机并网的复合控制

针对变速恒频风力发电机并网系统,提出了一种基于终端滑模和扩张状态观测器的转子电流复合控制方法.终端滑模控制不仅可以使得系统状态在有限时间内到达滑模面,而且使得状态在有限时间内沿着滑模面收敛到平衡点,使得发电机转子的d轴电流、q轴电流在有限时间内到达参考值,实现快速收敛和更好的跟踪精度.采用扩张状态观测器观测出系统扰动并进行前馈补偿,这有利于减小终端滑模控制所需要的切换增益而削弱可能的抖振现象,使系统得到更平滑的定子电压波形.仿真结果表明,该复合控制策略对参数摄动和扰动具有更强的鲁棒性,并网系统具有优良的动态性能.

Composite control for cutting-in control of variable speed constant frequency doubly fed wind power generator

This paper proposes a rotor current composite control method based on the terminal sliding mode control(TSM) and extended state observer(ESO) for cutting-in system of variable speed constant frequency doubly-fed induction generator(DFIG).TSM can make the states not only reach the manifold in finite time,but also converge along the sliding surface to the equilibria in finite time.Thus,the generator d-axis current and the q-axis current are drived to the reference values in finite time,obtaining a faster convergence and a better tracking precision.Moreover,the ESO is introduced to estimate system disturbances.The estimated value is employed for feed forward compensation against disturbances.This helps to reduce the required value of switching gain for the terminal sliding mode control method,which can reduce the chattering phenomenon of system and obtain a smooth stator voltage waveform.The simulation results show that the composite control strategy produces a better robustness against varying parameters and disturbances,the cutting-in control system has a better dynamic performance.