Small-signal methods for electric ship power systems

Abstract

This paper presents an overview of small-signal analysis methods applicable to shipboard power systems that use ac as the primary form of power distribution. Future electric ship power systems will arguably be power electronic systems due to wide-spread use of power electronic circuits and control. The inherent nonlinear behavior of switching power converters coupled with the time-varying operation trajectory of ac power systems represents a major difficulty for small-signal analysis of such systems, namely, traditional small-signal linearization techniques cannot be directly applied to develop linear, time-invariant system models. Possible solutions to this problem include modeling using dynamic phasors, transformation into a rotating (dq) reference frame, reduced-order modeling, and harmonic linearization. This paper provides an overview of these methods and discusses their utilities as well as limitations for shipboard power system stability and power quality analysis.