AC Power Theory From Poynting Theorem: Identification of the Power Components of Magnetic Saturating and Hysteretic Circuits

This paper is the continuation of an earlier work on narrowing the theoretical gap with power theory (or “power definitions”) for nonlinear circuits. The underlying idea is to compute the active and reactive powers of a general single-phase circuit from only the knowledge of the instantaneous voltage and current at the circuit terminals. This is done to shed light on the long-standing controversy on the physical meaning of the various types of powers defined for nonsinusoidal waveforms. Previously, only the power components of nonlinear switching circuits consisting of constant resistive and inductive elements were properly identified. The method is now extended to be suitable for the identification of the power components of general single-phase nonlinear circuits including magnetic nonlinear components with saturation and hysteresis. The Poynting Theorem is applied to correctly identify the energy consumed in electrical elements (Joule losses) as well as the energy stored/restored and consumed in the hysteresis loop of magnetic elements. Numerous examples are presented for illustration and validation of the method.