Interaction Mechanism for Multiple Active Power Filters in DC Distribution Networks

Abstract

DC distribution network is the main development direction of the power distribution system. Due to the influence of electronic equipment and other factors, the system is very easy to produce second harmonics, which seriously affects the stability of the system and the safety of electrical equipment. Multi-filter collaborative filtering in DC distribution network has become one of the methods to control the second harmonic. However, due to the coupling interference between the filters, the filtering effect is affected by multiple factors. This paper establishes a Norton equivalent grid-connected model of multiple filters and proposes a method for analyzing the interaction mechanism of multiple filters based on the relative gain matrix theory. This method establishes the matrix relationship between the change in the output current of the filter and the change in the harmonic source current and analyzes the influence of the grid parameters and controller parameters in the multi-filter grid-connected system on the filtering effect of the filter, and proposes a reasonable parameter selection method. Finally, this paper establishes a DC distribution network model with multiple DC filters in PSCAD/EMTDC, and simulates the parameters affecting the filtering effect and verifies the rationality of the analysis in the scenario of multiple harmonic sources. In addition, it builds a semi-physical simulation model in RT-LAB to further verify the effectiveness of the method.

Keywords

• dc distribution network
• second harmonic
• dc active filter
• relative gain matrix
• interaction mechanism