An Alternative Realization of Droop Control and Virtual Impedance for Paralleled Converters in DC Microgrid

Abstract

In this paper, an alternative realization method of droop control and virtual impedance for paralleled converters in DC microgrids is proposed as complement to the existing method. The major feature of the proposed realization is that the virtual impedance behavior is realized by using current reference together with a properly designed low-pass filter. Therefore, it will inherently get rid of the noise problem in real-world measurement, which is critical when realizing inductive virtual components. In addition to that, the impact of low-pass filter used in the proposed method on the dynamic performance is also comparatively studied. To validate the proposed method, simulations and experiments are carried out. The results show that the proposed method can be fully compatible with existing methods. Moreover, the low-pass filter is proven to be optional, however, with a specially designed low-pass filter, the transient response of the system can be modified significantly.