A Refined Analytical Approach for Precise Estimation of Parasitic Capacitance in Current Sensors with Powder Cores

Powder magnetic cores substantially enhance Rogowski current sensors by improving sensitivity, signal quality, and form factor; however, they introduce problematic parasitic capacitance effects that compromise performance. Accurate modeling of these parasitic effects remains crucial for optimizing sensor design. This paper examines powder core electromagnetic characteristics, detailing the complex relationship between material properties, physical dimensions, and resulting electromagnetic field distributions. We extend conventional analytical frameworks by developing correction factors that account for previously neglected non-linear electric field coupling phenomena. These factors, derived through systematic finite element method (FEM) simulations, enable significantly improved parasitic capacitance prediction. Experimental validation using six distinct prototype configurations demonstrates the superior accuracy of our approach compared to traditional methods, particularly as geometric complexity increases.