Harmonic/State Model-Order Reduction of Nonlinear Networks

This paper presents a practical approach to obtain reduced-order models for electric networks expressed in the dynamic harmonic domain (DHD). The proposed method reduces the DHD system of ordinary differential equations first in the harmonic sense via a voltage-based frequency-scan procedure and subsequently in the state sense via truncated balanced realizations. The harmonic-selection and truncation stage substantially reduces the original full-size system. The state-reduction process is applied to the already harmonic-reduced system, achieving further reduction. Two networks are used as case studies to demonstrate the reduction properties of the proposed model-order reduction methodology.