双馈风力发电机空载并网控制策略对比分析

Comparative analysis and strategy review of doubly-fed wind power generator with no-load grid connection

以双馈式风力发电机空载数学模型为基础,分析现有双馈风力发电机并网控制策略原理,并从响应速度、控制精度及控制稳定性等方面对其进行综合对比。然后基于PSCAD/EMTDC仿真,对理论分析结果进行验证.仿真表明基于滞环比较电压开环控制,响应速度快,但精度较差;SPWM电压开环控制策略,精度较好;电压闭环控制策略稳定性好,响应速度较慢;滞环比较电压闭环控制在保持精度的基础上响应速度更快,与分析结果一致。最后通过不同初始运行转速的双馈风力发电机自动并网仿真,证明在超同步、亚同步以及同步状态下,以上4种控制策略均能实现双馈风机的顺利并网,且基本没有冲击电流.

Based on the noload mathematical model of doubly-fed wind power generator,this paper analyzes the grid-connected control strategy and the control process of present doubly-fed wind power generator.Then it compares the response velocity,the accuracy and stability of the control.It verifies the correctness of the theory and comparative analysis,based on the simulation experiment of PSCAD/EMTDC.Some conclusions are drawn as follows.Voltage open-loop control strategy based on hysteresis comparison has fast response but with poor accuracy.Voltage open-loop control strategy based on SPWM has a better accuracy.Voltage closed-loop control strategy has a better stability but its response speed is slow.Voltage closed-loop control strategy based on hysteresis comparison has a faster response speed on the basis of maintaining high accuracy.Finally,the authors simulate the characteristics of automatically grid-connected doubly-fed wind power generator,with different initial running speed.Meanwhile,under the hypersynchronous,subsynchronous and synchronous conditions,the double-fed wind generators under the above four control strategies can all achieve a smooth grid connection;there is no impact current basically.