Examination for a symmetric-flux ferrite core for three-phase converter applications

For galvanic isolation of a three-phase power supply, the common choice for cost and volume is the three-legged core. Unfortunately this type of core has an inherent power flux asymmetry attributable to the core geometry. This work focuses on a singular geometrical symmetric-flux core, which naturally solve asymmetry problem due to equal mutual impedances between phases. Magnetic circuit theory, finite-element analysis (FEA), and metric analysis of symmetric and three-legged core are used to illustrate the use and extent of the analytical results.