The influence of internal current loop on transient response performance of I-V droop controlled paralleled DC-DC converters

The external droop control loop of I-V droop control is designed as a voltage loop with embedded virtual impedance, so the internal current loop plays a major role in the system bandwidth. Thus, in this paper, the influence of internal current loop on transient response performance of I-V droop controlled paralleled dc-dc converters is analyzed, which is guided and significant for its industry application. The model which is used for dynamic analysis is built, and the root locus method is used based on the model to analyze the dynamic response of the system by shifting different control parameters. Analysis results show that any converter's inner current loop can influence all converters' dynamic responses in the system and the one with larger Virtual Resistance (VR) has greater effect. Increasing the proportional terms can decrease the fluctuations of current and voltage, and key parts of errors can be reduced more rapidly during dynamical process, but adverse effect on completely eliminating errors can be caused; increasing integral terms can enlarge current fluctuations during dynamical process, but the errors can be eliminated more rapidly. The experiments are performed to verify the analysis.