No abstract

Purpose Magneto-quasi-static fields emanated by inductive charging systems can be potentially harmful to the human body. Recent projects, such as TALAKO and MILAS, use the technique of wireless power transfer (WPT) to charge batteries of electrically powered vehicles. To ensure the safety of passengers, the exposing magnetic flux density needs to be measured in situ and compared to reference limit values. However, in the design phase of these systems, numerical simulations of the emanated magnetic flux density are inevitable. This study aims to present a tool along with a workflow, based on the Scaled-Frequency Finite Difference Time-Domain and Co-Simulation Scalar Potential Finite Difference schemes, to determine body-internal magnetic flux densities, electric field strengths and induced voltages into cardiac pacemakers. The simulations should be time efficient, with lower computational costs and minimal human workload. Design/methodology/approach The numerical assessment of the human exposure to magneto-quasi-static fields is computationally expensive, especially when considering high-resolution discretization models of vehicles and WPT systems. Incorporating human body models into the simulation further enhances the number of mesh cells by multiple millions. Hence, the number of simulations including all components and human models needs to be limited while efficient numerical schemes need to be applied. Findings This work presents and compares four exposure scenarios using the presented numerical methods. By efficiently combining numerical methods, the simulation time can be reduced by a factor of 3.5 and the required storage space by almost a factor of 4. Originality/value This work presents and discusses an efficient way to determine the exposure of human beings in the vicinity of wireless power transfer systems that saves computer simulation resources and human workload.

No abstract

Functionally graded materials (FGM) are applied in HVDC gas insulated lines (GIL) to control the electric field within the DC insulation system. In HVDC GIL, FGM with a spatial distribution of the electric conductivity (𝝈-FGM) is applied to control the electric field under DC steady state condition. However, besides DC steady state, different DC conditions occur, e.g. DC-on process, polarity reversal and lightning impulse. Under these conditions 𝝈-FGM is not sufficient to control the electric field, since these conditions result in transient capacitive fields, where the permittivity is decisive for the electric field. In this paper, we suggest combining 𝝈-FGM and a spatial distribution of permittivity (𝜺-FGM) in the spacer material to control the electric field around DC-GIL spacer for various DC-conditions, considering nonlinear material models for the insulating gas and the epoxy spacer. A variation of the spatial distribution of permittivity and conductivity in the spacer is investigated in this paper for an effective field reduction. The results show a reduction of the electric field intensity up to 65.8 %, when 𝝈/𝜺-FGM is applied.