Parasitic Capacitance Modeling of Inductors Without Using the Floating Voltage Potential of Core

Abstract

The analytical modeling of parasitic capacitances in inductors is commonly based on the energy-conservation law. Yet, in order to calculated the equivalent capacitances of inductors, the floating voltage potential of magnetic core is required to be pre-known in all previous modeling methods. This letter proposes an analytical method for calculating the parasitic capacitances of the inductors with low-resistivity cores, which does not require any prior knowledge of the floating core potential. The proposed modeling method can be extended to the transformers as well as multi-terminal magnetic devices. The experimental results verify the effectiveness of the proposed method.

Rethinking Basic Assumptions for Modeling Parasitic Capacitance in Inductors

“…The energy conservation method has also been used for calculating the explicit expressions of parasitic capacitance in inductors [12]- [15], [19]- [21], using a different assumption compared to the lumped capacitor network method.…”

“…Generally, there are two state-of-the-art physics-based modeling methods that can provide the explicit equations of the equivalent capacitance at the first resonant frequency: a) the lumped capacitor network method [11], [16]- [18] and b) energy conservation method [12]- [15], [19]- [21]. Both methods represent the inductors with an equivalent circuit constructed from multiple inductors and capacitors, with resistance usually neglected.…”

“…In the lumped capacitor network method [11], [16]- [18], the original equivalent circuit is simplified to a purely capacitive network, where elementary inductors are completely neglected since this method assumes that the impedance of elementary inductors is negligibly high at the first resonant frequency. In the energy-conservation based method [12]- [15], [19]- [21], the effects of elementary inductors are considered by the voltage drop between turns, where the voltage drop is assumed to be distributed linearly at each turn. Then, the equivalent capacitance between the two terminals of inductors is calculated by deriving the total energy in the electric field between the turns and matching it to the energy stored in the equivalent capacitance.…”

Rethinking Basic Assumptions for Modeling Parasitic Capacitance in Inductors

“…Generally, there are two state-of-the-art physics-based modeling methods that can provide the explicit equations of the equivalent capacitance at the first resonant frequency: a) the lumped capacitor network method [14], [19]- [21] and b) energy conservation method [15]- [18], [22]- [24]. Both methods represent the inductors with an equivalent circuit constructed from multiple inductors and capacitors, with resistance usually neglected.…”

“…In the lumped capacitor network method [14], [19]- [21], the original equivalent circuit is simplified to a purely capacitive network, where elementary inductors are completely neglected since this method assumes that the impedance of elementary inductors is negligibly high at the first resonant frequency. In the energy-conservation based method [15]- [18], [22]- [24], the effects of elementary inductors are considered by the voltage drop between turns, where the voltage drop is assumed to be distributed linearly at each turn. Then, the equivalent capacitance between the two terminals of inductors is calculated by deriving the total energy in the electric field between the turns and matching it to the energy stored in the equivalent capacitance.…”