一种基于磁链估算的单相CHB变流器无锁相环控制策略  

PLL-less Control for Single-phase CHB Converter Based on Flux Observer

作　　者：刘金宝 杨达亮[1,2] 邵大帅 彭祖文 李政 LIU Jinbao;YANG Daliang;SHAO Dashuai;PENG Zuwen;LI Zheng(Guangxi Key Laboratory of Power System Optimization and Energy Technology(Guangxi University),Nanning 530004,Guangxi Zhuang Atutonomous Region,China;College of Electrical Engineering,Guangxi University,Nanning 530004,Guangxi Zhuang Autonomous Region,China)

机构地区：[1]广西电力系统最优化与节能技术重点实验室(广西大学),广西壮族自治区南宁市530004 [2]广西大学电气工程学院,广西壮族自治区南宁市530004

出　　处：《电网技术》2022年第10期4030-4038,共9页Power System Technology

基　　金：国家自然科学基金项目(61861003)。

摘　　要：为提高并网变流器的控制性能,提出一种新型的无锁相环控制方法,可有效避免锁相环(phase-locked loop,PLL)对动态性能的影响,控制结构得到简化。基于单相级联H桥(cascaded H-bridge,CHB)多电平变流器,首先引入一种增强的观测器,可准确估算出正弦的磁链基波信号;其次,推导了无锁相环控制的实现过程,并给出指令电流的计算公式。然后,针对电网电压谐波干扰的问题,通过建立阻抗模型,分析了系统的谐波抑制能力;并提出一种改进的电流控制器,实现了并网电流无谐波和快速动态响应的控制目标。此外,平衡控制方法使变流器直流侧电压保持稳定。最后,仿真和实验验证结果表明了所提方法的有效性。In order to improve the control performance of grid connected converter,a new method of the phase-locked loopless(PLL-less)control is proposed in this paper.This method will effectively eliminate the influence of phase-locked loop(PLL)on its dynamic performance and simplify its control system.Firstly,based on the single-phase cascaded H-bridge(CHB)multilevel converter,an enhanced observer is introduced to accurately calculate the fundamental component of grid flux.Secondly,the realization process of PLL-less control is deduced in detail,and the expression of current reference is given.Then,aiming at the problem of harmonic interference in the grid voltage,the system harmonic suppression ability is analyzed through the impedance modeling.Therefore,a modified current controller is proposed,realizing the control targets of the sinusoidal output current and the fast dynamic response.In addition,the balancing control is adopted to maintain the stability of the DC-link voltages.Finally,the proposed method is verified by simulation and experiment.

关 键 词：级联H桥变流器 无锁相环控制 磁链估算 无网压传感器 畸变电网电压 

分 类 号：TM721[电气工程—电力系统及自动化]