双馈感应发电机参与电网一次调频的改进限转矩控制方法

Improved Torque Limit Control Method for Doubly Fed Induction Generator Participating in Primary Frequency Regulation of Power Grid

大规模风电并网,将导致电力系统惯性及相对备用容量降低,给电网频率控制带来困难.因此,如何对风机输出进行调整,使其参与电网调频成为亟待解决的问题.本文对此展开研究,首先,描述了风力发电机的传统限转矩控制原理,并对其参与电网一次调频进行了效果分析;其次,针对传统限转矩控制导致的风机转轴所受应力过大及频率二次跌落的问题,提出改进的限转矩控制方法,通过改进限转矩控制器的设计进行风机动能提取过程的优化,以减小频率二次跌落;最后,通过与传统限转矩控制、传统虚拟惯性控制和风机不参与调频3种方式的仿真对比分析,验证了所提方法的可行性和有效性.

Large scale wind power integration will lead to the reduction of inertia and relative reserve capacity in power system,which will bring about the difficulties of frequency control.Therefore,it has become an urgent problem which is how to adjust the wind turbine output and make it participate in frequency regulation in power grid.Firstly,the principle of the traditional torque limit control for wind turbine is described,and the effect of its participation in primary frequency regulation is analyzed.Secondly,an improved torque limit control method is proposed in order to solve the problems of excessive stress on the wind turbine shaft and frequency secondary drop caused by the traditional torque limit control.Moreover,the process of power extraction is optimized and the frequency secondary drop is reduced by improving the design of the torque limit controller.Finally,the feasibility and effectiveness of the proposed method are verified by comparing with traditional torque limit control,traditional virtual inertia control and wind turbine not participating in frequency modulation.