# Chassis Influence on the Exposure Assessment of a Compact EV during WPT Recharging Operations

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## Abstract

**:**

## 1. Introduction

_{2}emissions [1]. Thus, the usage of compact electric vehicles (EVs), together with the development of new mobility services, is the most sustainable solution, at least in urban areas. However, despite having a wide appeal, EV deployment on a global scale is still hampered by the battery technology and charging infrastructure [2]. These drawbacks can be resolved through static or dynamic wireless power transfer (WPT) systems and their widespread applications in an improved charging infrastructure for EVs [3].

## 2. Materials and Methods

#### 2.1. Car Modeling

#### 2.2. WPT System Configuration

#### 2.3. Exposure Scenarios for Numerical Dosimetry

#### 2.4. Magnetic Field Evaluation

**B**-field) is then evaluated in a post-processing stage inside the box regions embedding the anatomical models (see Figure 3a), which are not considered in this stage since they do not perturb the magnetic field at such frequencies, as demonstrated in [22].

#### 2.5. LF Dosimetry

**B**-field at discrete points in a bounded hexahedral grid, and Equation (5) is then used to get the

**A**-field at the same points. This

**A**-field distribution is interpolated on the human model, and eventually, the electric scalar potential is obtained by solving Equation (4). It is worth stressing that Figure 5 is purely descriptive, and more points were used in the actual simulations. The relative error introduced in the solution is shown to be negligible for a discretization of the bounded volume in the order of centimeters [14].

## 3. Numerical Dosimetry Results

#### 3.1. RL Numerical Dosimetry

#### 3.2. BR Numerical Dosimetry

## 4. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 1.**Commercial CAD model of a FIAT 500 (

**a**), simplified CAD model for electromagnetic simulations (

**b**), and the surface mesh used in this paper (

**c**).

**Figure 4.**Convergence of the GMRES solver when the coils are perfectly aligned in the case of a car body made of aluminum (blue) or carbon fiber (red).

**Figure 5.**The human model is bounded in a hexahedral grid. Knowing the $\mathbf{B}$-field at the blue points, it is possible to define a compatible $\mathbf{A}$-field that, after interpolation, is used as the source term in Equation (4).

**Figure 6.**$\mathbf{B}$-field distributions for the aligned (

**a**) and misaligned (

**b**) coil positions with the Al chassis.

**Figure 7.**$\mathbf{B}$-field distributions for the aligned (

**a**) and misaligned (

**b**) coil positions with the carbon fiber (CF) chassis.

**Figure 8.**Induced electric field distributions inside Ella (left) and Duke (right) for the aligned (

**a**) and misaligned (

**b**) coil positions in the Al chassis and for the aligned (

**c**) and misaligned (

**d**) coil positions in the CF chassis. ${E}_{norm}$ is the logarithmic electric field normalized to the peak value. ${E}_{lim}$ is the basic restriction (BR) = $11.48\phantom{\rule{3.33333pt}{0ex}}\mathrm{V}/\mathrm{m}$ (the red area is the portion where the BR is exceeded).

Exposure | Chassis | ${\mathit{E}}_{\mathbf{max}}$ | ${\mathit{E}}_{99.9}$ | ${\mathit{E}}_{99}$ | Overexposure |
---|---|---|---|---|---|

Scenario | Material | (V/m) | (V/m) | (V/m) | (dB) |

Ella–Aligned | aluminum | 8.26 | 1.84 | 0.71 | −18.48 |

Ella–Misaligned | 7.69 | 1.36 | 0.57 | −19.22 | |

Duke–Aligned | 0.27 | 0.11 | 0.07 | −44.11 | |

Duke–Misaligned | 0.53 | 0.25 | 0.12 | −39.56 | |

Ella–Aligned | carbon fiber | 19.21 | 5.86 | 1.71 | −16.48 |

Ella–Misaligned | 24.00 | 6.94 | 1.76 | −16.23 | |

Duke–Aligned | 0.76 | 0.36 | 0.14 | −38.11 | |

Duke–Misaligned | 0.90 | 0.44 | 0.17 | −36.45 |

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**MDPI and ACS Style**

De Santis, V.; Giaccone, L.; Freschi, F.
Chassis Influence on the Exposure Assessment of a Compact EV during WPT Recharging Operations. *Magnetochemistry* **2021**, *7*, 25.
https://doi.org/10.3390/magnetochemistry7020025

**AMA Style**

De Santis V, Giaccone L, Freschi F.
Chassis Influence on the Exposure Assessment of a Compact EV during WPT Recharging Operations. *Magnetochemistry*. 2021; 7(2):25.
https://doi.org/10.3390/magnetochemistry7020025

**Chicago/Turabian Style**

De Santis, Valerio, Luca Giaccone, and Fabio Freschi.
2021. "Chassis Influence on the Exposure Assessment of a Compact EV during WPT Recharging Operations" *Magnetochemistry* 7, no. 2: 25.
https://doi.org/10.3390/magnetochemistry7020025