System interactions and design considerations for distributed power systems

Abstract

Methods of analysis and important design considerations for distributed power systems (DPS) are addressed. A generalized analysis of subsystem interaction is presented. Emphasis is placed on absolute stability and eigenvalue location of the integrated system. Terminal properties of the decoupled subsystems are used in determining the stability criteria. Either analytical models or empirical data may be used in the interaction analysis.

Design of EMI filters for a two-stage DPS is comprehensively discussed. A detailed analysis of the effects of input filters on current-mode controlled single-module regulators is given. It is shown that the criteria used to minimize filter interaction for voltage-mode and current-mode controlled regulators are identical. The results of the single-module regulator input filter interaction analysis are extended to the multi-module DPS case. Both line input filters and intermediate bus filters are designed for stability and to minimize interaction with the regulator modules. Implications of non-minimal dimensional subsystems are discussed. The eigenvalues due to parallel interaction are described, and it is shown how appropriate damping can be used to insure their stability. Straight-forward design guidelines are provided for the filters.

Interaction of a non-ideal generator source with the DPS is described. This provides a useful application of the general subsystem interaction analysis. Stability is determined from different points in the system, and subsystem impedances are used to qualitatively describe the integrated system eigenvalue location.