Reduced-order extended harmonic domain modeling of switched networks

This paper presents an extended harmonic domain (EHD) reduced-order modeling technique of switched networks based on dominant frequencies. The technique is readily applicable to power electronic converters involved in photovoltaic (PV) and wind generation systems. Generally, the instantaneous product between switching function and voltage/current variable is represented in the EHD as a product of a (theoretically infinite) Toeplitz-type matrix of the former and a harmonic domain (HD) vector of the latter. The proposed approach consists in two simple, yet effective, basic actions. Firstly, the harmonic spectrum of the involved switching function is considered for the harmonic dominancy characterization. Secondly, the commonly used arrangement of the Toeplitz-type matrix is modified in this paper to consider interaction between dominant frequencies only. The obtained reduced-order models provide computational savings while keeping accuracy. Two case studies, involving PV and wind turbine generation systems, are presented to validate the proposed methodology.