中文摘要：

数字控制系统中不可避免地存在延时,而延时环节会改变系统的相位特性,影响系统稳定性。文中以逆变侧电感单电流环控制为例,在模拟域和数字域下分析了系统的稳定性,系统地研究了数字控制系统中的延时时间对稳定性的影响,在此基础上,详细分析了保持系统稳定的延时时间范围。并从改善系统稳定性的角度,提出了一种数字控制延时的优化设计与延时调整方法。在一台并网逆变器上进行实验,试验结果验证了分析的正确性和所提出方法的有效性。

英文摘要：

Delay is inevitable in digital-controlled systems and the delay element changes system phase-frequency characteristics, thus affects system stability. The system stability of the inductor-capacitor-inductor（LCL）-type Gridconnected inverter with single-loop control based on the converter-side current is analyzed both in the continuous domain and the discrete domain. The influence of delay time on system stability is systematically studied, and the delay time range to keep system stable is further analyzed. A delay time control method, which is capable of adjusting delay time is proposed to improve system stability. The experiment results conducted in a single-phase gird-connected inverter verify the analysis result and the proposed method.