并网逆变器中数字控制延时对系统稳定性影响与其优化设计-邹常跃.pdfVIP

35 2 Vol.35 No.2 Jan.20, 2015 2015 1 20 Proceedings of the CSEE ©2015 Chin.Soc.for Elec.Eng. 411 DOI 10.13334/j.0258-8013.pcsee.2015.02.020 0258-8013 (2015) 02-0411-07 TM 46 (() 430074) Influence of Delay on System Stability and its Optimization in Grid-connected Inverters ZOU Changyue, LIU Bangyin, DUAN Shanxu, LI Rui (State Key Laboratory of Advanced Electromagnetic Engineering and Technology (Huazhong University of Science Technology), Wuhan 430074, Hubei Province, China) ABSTRACT: Delay is inevitable in digital-controlled systems 0 and the delay element changes system phase-frequency characteristics, thus affects system stability. The system stability of the inductor-capacitor-inductor (LCL)-type Grid- [1](pulse connected inverter with single-loop control based on the width modulationPWM) converter-side current is analyzed both in the continuous L domain and the discrete domain. The influence of delay time --(inductor-capacitor-inductor LCL) on system stability is systematically studied, and the delay time [2-3] range to keep system stable is further analyzed. A delay time control method, which is capable of adjusting delay time is [4-5]LCL proposed to improve system stability. The experiment results conducted in a single-phase gird-connected inverter verify the LCL analysis result and the proposed method. [1-14] KEY WORDS: inductor-capacitor-inductor (LCL) filter; grid- [6] connected