The CCS Graduate School of Green Transportation, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34051, Korea.
Radio and Satellite Research Division, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea.
Int J Environ Res Public Health. 2021 Dec 21;19(1):44. doi: 10.3390/ijerph19010044.
The concept of a coupling factor was introduced in International Electrotechnical Commission (IEC) 62311 and 62233 to provide a product safety assessment that considers the localized exposure when an electromagnetic field (EMF) source is close to the human body. To calculate the coupling factors between the human body and EMF source, a numerical calculation should be carried out to calculate the internal quantities of the human body models. However, at frequencies below 10 MHz, the computed current density or internal electric field has computational artifacts from segmentation or discretization errors. Specifically, coupling factors are calculated based on the maximum values, which may include computational artifacts due to abnormal peaks. In this study, we propose an improved calculation method to remove computational artifacts by applying the 99.99th percentile in calculating the coupling factors without underestimation. The performance of the proposed method is verified through a comparison based on various human body models with wireless power transfer (WPT) systems and compliance with the reference levels and basic restrictions. The results indicate that the proposed method can provide uniform coupling factors by reducing the computational errors by up to 65.3% compared to a conventional method.
IEC 62311 和 62233 引入了耦合因子的概念，以提供产品安全评估，考虑到电磁场 (EMF) 源接近人体时的局部暴露。为了计算人体与 EMF 源之间的耦合因子，应进行数值计算以计算人体模型的内部量。然而，在 10 MHz 以下的频率下，计算出的电流密度或内部电场会因分段或离散化误差而产生计算伪影。具体来说，耦合因子是基于最大值计算的，其中可能包括由于异常峰值引起的计算伪影。在本研究中，我们提出了一种改进的计算方法，通过应用 99.99%分位数来计算耦合因子，而不会低估，从而消除计算伪影。通过与具有无线功率传输 (WPT) 系统的各种人体模型进行比较，并符合参考水平和基本限制，验证了所提出方法的性能。结果表明，与传统方法相比，所提出的方法可以通过将计算误差降低多达 65.3%，提供均匀的耦合因子。
