Efficiency analysis of induction heating systems with respect to electromagnetic shielding film's properties

Abstract

Enhancing induction heating efficiency requires precise material selection and optimal structural design, including consideration of electromagnetic shielding materials. This study explores the impact of material properties on high-frequency resistance (Rs), inductance (Ls), and energy consumption. Metal powder-filled composites and ferrites typically exhibit lower relative permeability (μr) compared to nanocrystals, with an increase in μr leading to enhanced Ls, Rs, and heating efficiency. However, nanocrystalline shielding films show a unique trend where heating efficiency initially rises and then declines for multi-layered films, with a critical point at μr = 1500. Magnetic fragmentation induced imperfections in nanocrystalline films disrupt eddy current paths, reducing energy loss and improving heating efficiency as μr decreases. The notion of “relative conductivity (σ')” is introduced to demonstrate that a reduction in the fragmentation extent leads to the expansion of eddy current pathways as μr increases. This augmentation enhances both σ' and the imaginary permeability (μ''), leading to increased eddy current losses that affect overall efficiency. In evaluating energy efficiency for nanocrystals, it is crucial to consider μ', μ'', and σ' in conjunction, as there is a positive correlation between μ'' and σ'. Finite element analysis (FAE) confirms these observations, showing how film properties impact efficiency. Comprehending shielding mechanisms not only optimizes induction heating but also benefits applications such as wireless charging for electric vehicles and mobile communication devices.