基于广义旋转角的三相锁相环

Three-phase PLL Based on Generalized Rotation Angle

锁相环技术是新能源并网发电、电能质量分析与控制等领域的关键技术之一。针对传统SRF-PLL锁相环易受电压幅值波动影响且需同步旋转坐标变换的问题,提出一种基于αβ静止坐标系广义旋转角的三相锁相环。通过三角函数变换,研究了该广义旋转角与电压锁相角之间的关系,提出基于该广义旋转角的三相锁相环,可直接应用于其他电压等级而无须重新整定控制参数。应用延时法提取基波电压正序分量,有效克服了谐波与电压暂降等电能质量扰动对锁相结果的影响。仿真结果表明所提出的锁相环具有较强的鲁棒性,动态特性好,能够在各种扰动下实现电压的快速精确锁相。

Phase-looked loop(PLL)is one of the key technologies in the fields of grid-connected new energy and the analysis and control of power quality.Considering that for the conventional synchronous reference frame(SRF)-PLL technology,PLL is vulnerable to fluctuations in voltage amplitude and it needs to coordinate with SRF,a three-phase PLL based on generalized rotation angle(GRA)in anαβstationary reference frame is proposed in this paper.The relationship between GRA and grid phase angle is studied through trigonometric function transformations,and a threephase PLL is formulated on the basis of GRA,which can be applied to other voltage grades directly without retuning the control parameters.A generalized delayed signal cancellation(GDSC)method is used to extract the fundamental-frequency positive-sequence(FFPS)component of voltage,eliminating the effect of power quality disturbances(e.g.,harmonic and voltage sag)on the phase lock result.Simulation results show that the proposed PLL has stronger robustness and better dynamic characteristics,and it can realize a fast and accurate phase lock under different disturbances.