电网非理想情况下的双馈风电机组锁相控制

Control of Phase Locked Loop for Wind Power Generation Under Non-Ideal Grid Conditions

随着风力发电规模的不断增加,电网非理想情况下的风电机组并网运行性能成为研究的重点。为保证双馈风电机组在电网非理想情况时能够准确、快速地跟踪电网的相位和频率,提出了一种基于abc坐标系延时算法的dq锁相方法。该方法在传统的软件锁相方法基础上,利用延时信号算法来消除由电压不对称所引入的锁相环路二次波动量,通过合理设计环路滤波器来增加锁相环路对电网5、7次谐波量的衰减系数。仿真和实验结果表明,该锁相方法不仅能很好地抑制电网三相不对称和畸变所引起的锁相环相位波动,同时也获得了较好的动态性能,能够在电网发生故障时快速地跟踪电网相位和频率,可为电网非理想情况下双馈风电机组的可靠运行提供准确的电网频率和相位信息。

With increase of installed wind power capacity,the operation performance of wind power system under non-ideal grid conditions has become a research emphasis.In order to track phase and从 frequency of grid accurately and quickly,this paper presents a new phase locked loop（PLL） method by using delay signal cancellation in the abc coordinate system.Based on the traditional method of software PLL,the delay signal cancellation algorithm is used to eliminate the second fluctuation of the control loop under unbalanced grid condition.A design method for the PLL loop controller is also developed in order to increase the attenuation coefficient of 5th and 7th harmonics.Simulation and experimental results show that the proposed PLL system not only effectively attenuates the loop fluctuation which is caused by non-ideal grid,but also obtain good dynamic performance.The PLL system can provide accurate phase and frequency information for safe and reliable operation of wind turbines under grid faults.