Magneto-inductive waves in metamaterial-based wireless power transfer systems

• Ano de defesa: 2023
• Autor(a) principal: Freitas, Felipe Machado de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Centro Federal de Educação Tecnológica de Minas Gerais / Universidade Federal de São João del-Rei; Programa de Pós-Graduação em Engenharia Elétrica; Brasil; CEFET-MG / UFSJ
• Palavras-chave em Português: Circuitos eletrônicos – Modelos; Materiais eletrônicos; Materiais magnéticos; Transmissão de energia sem fio
• Link de acesso: https://repositorio.cefetmg.br//handle/123456789/1015

This work proposes a method of analysis of printed Magnetic Coupled Wireless Power Transfer (MCWPT) systems operating in a few MHz based on Circuit Model (CM). Initially, the effect of resonant surfaces on wireless energy transmission and the advantages of their use are discussed. Therefore, the resulting increase in efficiency is discussed based on the Magneto-Inductive Waves (MIW) theory. Furthermore, the feasibility of using metasurfaces in Wireless Power Transfer (WPT) systems where the transmitter and receiver are misaligned or are coplanar is analyzed. Finally, possibilities for optimizing the impedance of WPT systems to increase transmission efficiency are also presented. An analytical model is proposed to calculate the self-inductance of printed inductors, their characteristic resistance, and the mutual inductance between coils. The presented formulation for calculating the mutual inductance between inductors is based on Neumann’s formula. Due to the generality of this approach, it can also be applied to more complex structures, such as metasurfaces. In the analysis of the MCWPT CM, it is considered that the unknown current along the microstrip is considered as a single value distributed in each modeled coil. First, computational aspects related to model implementation are discussed. Then, the calculated results are compared step by step with commercial software based on electromagnetic methods in the frequency domain. Then, the microstrip model is experimentally validated with measurements of transmission coefficients from an MCWPT printed in FR4, operating at 24. A new design based on printed square coils is also proposed, but now with reduced size and working at 13.56 . A frequency domain analysis on how the frequency and receiver position on the metasurface affect efficiency is done. Then, the variation of the input impedance and the current distribution on the surface of the metamaterial are analyzed in relation to the variations in the position of the receiver and in the charge rate on the resonant surface. For this, the MIW theory is used in a specific application: Passive Position Tracking in Dynamic MCWPT Systems. Finally, it discusses the importance of knowing the current distribution and impedance optimization parameters for an MCWPT system. The results show that the proposed method is valid for modeling printed inductors. In addition, the model proved to be computationally more efficient for the analysis of large systems when compared to commercial full-wave simulation software, and the practical results point to conformity.