不平衡电网下电流源型PWM整流器改进型无差拍控制  

Improved Deadbeat Control of Current-source PWM Rectifier under Unbalanced Grid

作　　者：肖蕙蕙[1] 何黎鹏 郭强[1] 黄勇军 胡前云 张越飞 XIAO Huihui;HE Lipeng;GUO Qiang;HUANG Yongjun;HU Qianyun;ZHANG Yuefei(Chongqing Engineering Technology Research Center of Energy Internet,Chongqing University of Technology,Chongqing 400054)

机构地区：[1]重庆理工大学重庆市能源互联网工程技术研究中心,重庆400054

出　　处：《电气工程学报》2024年第2期119-127,共9页Journal of Electrical Engineering

摘　　要：三相电流源型PWM整流器运行在电网电压不平衡情况下,引起直流侧及网侧电流存在大量低次谐波,势必对后级变换器供电稳定性、安全性等存在不利影响。针对该问题,首先建立整流器数学模型,推导出不平衡电网下直流侧电压和网侧电流表达式,揭示出系统直流侧和网侧电流产生低次谐波的机理。其次,根据瞬时功率理论设计内环电流参考指令,并利用无差拍控制实现网侧电流对参考电流的跟踪。然而传统无差拍控制存在延时问题,将影响网侧电流的跟随性能,造成电能质量下降。为解决该问题,提出了网侧电流内环改进型无差拍控制,利用两步预测法补偿系统延时。最后,基于Matlab/Simulink平台搭建仿真模型,验证所提控制策略的正确性与有效性。结果表明,所提方法能有效抑制直流侧和网侧电流低次谐波,实现网侧电流正弦化和直流侧电压稳定输出。Three-phase current source PWM rectifier runs under the unbalanced grid voltage,which causes a large number of low-order harmonics in DC side and grid side current,which is bound to have adverse effects on the power supply stability and safety of the later converter.To address this problem,firstly,a mathematical model of rectifier is established,and the expressions of DC-side voltage and grid-side current under unbalanced power grid are derived,revealing the mechanism of low-order harmonics generated by DC-side and grid-side current of the system.Secondly,the inner-loop current reference command is designed based on the instantaneous power theory,and the deadbeat control is used to realize the tracking of the grid-side current to the reference current.However,the traditional deadbeat control has a delay problem,which will affect the following performance of grid-side current and cause the power quality to decline.In order to solve this problem,an improved deadbeat control based on inner loop of grid-side current is proposed,and the system delay is compensated by two-step prediction method.Finally,a simulation model is built based on Matlab/Simulink platform to verify the correctness and effectiveness of the proposed control strategy.The results show that the proposed method can effectively suppress the low-order harmonics of DC side and grid side current,and realize sinusoidal grid side current and stable DC side voltage output.

关 键 词：电流源型PWM整流器 不平衡电网电压 改进无差拍控制 谐波分析 

分 类 号：TM461[电气工程—电器]