High-Frequency Electromagnetic Analysis and Parasitic Capacitance Derivation of Single-Layer NiZn Toroidal Cores With Different Winding Techniques

In the high-frequency (HF) region, NiZn toroidal cores demonstrate enhanced efficiency due to their low core losses and stable permeability. However, the parasitic capacitance generated at HF can seriously affect the performance of cores. Thus, accurate modeling the parasitic capacitance of NiZn toroidal cores is essential due to the widespread application in the HF domain. This paper examines the actual electromagnetic behavior of NiZn toroidal cores, which are treated as dielectrics, diverging from previous models that often relied on the perfect electric conductor (PEC) hypothesis. Then, the impact of various winding methods on core capacitance is also explored. Based on the electromagnetic analysis, a new distributed capacitance network for NiZn toroidal cores with different winding method is proposed. Moreover, this paper presents a new method for capacitance derivation based on 2D FEM simulation, which demonstrates considerable accuracy and reduces computational resources. The paper also offers a detailed explanation of the physical significance underlying the proposed model. Comparative analysis of both models is presented, and the efficacy of the suggested model is substantiated through simulations and experimental validations in six distinct scenarios.