The magnetic resonant wireless power transfer (WPT) system with a class E inverter has wide application in mid-range power transmission, especially for several megahertz scenario. However, it is cumbersome for the existing modeling and analysis methods to obtain the analytical solution to the system variables, which limits the evaluation of system characteristic. This paper proposes a nonlinear mathematical model for the WPT system with a class E inverter. The equivalent small parameter method (ESPM) is first adopted to solve the proposed six-order nonlinear model, and symbolic-form steady-state periodic solutions are yielded. During the whole solving process, only three iteration steps are needed for the proposed method. Compared with other existing modeling and analysis methods, the symbolic periodic results acquired by the ESPM exhibit sufficient accuracy by virtue of the combination of more higher harmonics. Meanwhile, the calculation complexity is simplified remarkably. Simulation and available experiments validate the effectiveness and accuracy of the proposed method.

中文翻译：

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基于等效小参数法的磁共振WPT系统非线性建模与谐波分析

带有E类逆变器的磁谐振无线电力传输（WPT）系统在中距离电力传输中具有广泛的应用，特别是对于几兆赫兹的场景。然而，现有的建模和分析方法获取系统变量的解析解较为繁琐，限制了对系统特性的评价。本文提出了具有 E 类逆变器的 WPT 系统的非线性数学模型。首先采用等效小参数法（ESPM）求解所提出的六阶非线性模型，得到符号形式的稳态周期解。在整个求解过程中，所提出的方法只需要三个迭代步骤。与现有的其他建模和分析方法相比，由于更多高次谐波的组合，ESPM 获得的符号周期结果表现出足够的准确性。同时，显着简化了计算复杂度。仿真和可用实验验证了所提出方法的有效性和准确性。