Tao Zhang, Dezhi Dong
Research Center for Photovoltaic System Engineering of Ministry of Education, Hefei University of Technology, Hefei, 230009, China.
Dongguan Jishi Electric Co., Ltd, Dongguan, 523808, China.
Sci Rep. 2024 May 28;14(1):12169. doi: 10.1038/s41598-024-62702-y.
Aiming at the common problems of frequency variations and harmonics in complex power grids, an improved inverse Park transform phase locked loop (IPT-PLL) technology for single-phase converters suitable for micro grid systems is proposed. Firstly, in the phase detection of PLL, the α component of Park transformation is selected as the reference voltage, and its orthogonal component is constructed using a 1/4 fundamental period delay method. Secondly, Lagrange interpolation polynomials are introduced to approximate fractional delay to solve the problem of delay calculation errors caused by frequency changes. Thirdly, in order to compensate for the poor ability of traditional proportional integral (PI) regulators, multi resonant controllers are superimposed to suppress low order harmonic disturbances. Finally, the design method and system performance of the PI regulator and each resonant controller are analyzed theoretically. The experimental results show that the proposed improved IPT-PLL method has strong adaptability to complex power grids. It can significantly improve the tracking performance of power grid frequency, suppress the interference of low order harmonics and DC bias. And it has good dynamic and static performance.
针对复杂电网中频率变化和谐波等常见问题，提出了一种适用于微电网系统单相变流器的改进型逆Park变换锁相环（IPT-PLL）技术。首先，在锁相环的相位检测中，选择Park变换的α分量作为参考电压，并采用1/4基波周期延迟法构建其正交分量。其次，引入拉格朗日插值多项式来逼近分数延迟，以解决频率变化引起的延迟计算误差问题。第三，为了弥补传统比例积分（PI）调节器能力不足的问题，叠加多谐振控制器以抑制低阶谐波干扰。最后，从理论上分析了PI调节器和各谐振控制器的设计方法及系统性能。实验结果表明，所提出的改进型IPT-PLL方法对复杂电网具有很强的适应性。它能显著提高电网频率跟踪性能，抑制低阶谐波和直流偏置的干扰，且具有良好的动静态性能。
