Wide bandwidth system identification of MVDC distribution system by applying perturbations to an existing converter

Abstract

This paper presents a digital network analyzer technique to actively monitor the proposed MVDC distribution system for the US Navy's all-electric ship by using the existing power electronic converters to make wideband measurements of small-signal transfer functions and system impedances. The converters themselves become the excitation source and analysis tool for detecting changes in converter dynamics and impedances. This information can be used for fault detection and localization, stability and performance improvement using adaptive control, and for distributed control. The correlation-based analysis is examined in its application for obtaining several converter-level and system-level terminal characteristics. A scheme for an adaptive control platform is described that is able to correct for multiple converter system changes using the information-rich frequency response data obtained through the identification procedure. Simulation results are provided for several realistic scenarios, in which targeted control adaptation prevents system instability and improves performance.