一种改进的阻抗比判据

Improved Impedance Criterion

在直流分布式电源系统中,按单独工作模式设计的子系统之间的相互作用将导致电源系统动态性能下降甚至不稳定。M idd lebrook判据是分析分布式电源系统稳定性的经典方法,但不能保证系统的绝对稳定性及各子系统原有的动态性能。本文基于分布式电源系统小信号模型,研究了子系统之间的相互作用问题,给出一种改进的阻抗比判据,该判据能保证各子系统原有的稳定性和动态性能。分析实例与实验结果证明理论分析的正确性,从而为源变换器的优化设计提供了理论依据。

A DC distributed power system is physically made up of many sources and load converters. Usually each subsystem is designed based on its own stand-along operation. After system integrating the interaction between subsystems can cause performance degradated or even instable. Middlebrook criterion is a classical method for examining small signal stability of the DC distributed power system. However, it cannot absolutely guarantee the stability and the primary dynamic performance of the subsystems. Based on a small signal model, this paper defines the impedance specification for the stable DC distributed power system. To improve the Middlebrook criterion, an improved impedance specification for the source converter is proposed. When the improved impedance specification is satisfied, the source converter has the same stability and dynamic performance. Theoretical analysis verfied by the simulation and experimental results show that the impedance specification is sufficient to guarantee the stability and the dynamic performance of the source converter. It provides a theoretical basis for the optimized design.