This paper presents a thermal investigation of lightweight on-board receiver modules of wireless power transfer systems for electric vehicles. The studied modules are capable of receiving up to 11 kW at a resonance frequency of 85 kHz over a distance of 110–160 mm. The receiver modules were built as sandwich and space–frame concept to design stiff and lightweight structures. The high transmission power of automotive wireless power transfer systems combined with the multi-part assembly of receiver modules led to challenges in heat management. To address this, the physical behaviour of the proposed lightweight concepts were studied on component and system level using a hardware-in-the-loop testing facility for wireless power transfer systems. Special emphasis was laid on the validation of a thermal simulation model, which uses analytical calculated power losses taking into account their temperature dependency. The proposed simulation model is consistent with the experimental validation of the critical active components. The performed systematic studies build the basis for a more sophisticated thermal dimensioning of various constructions for wireless power transfer modules.

The thermal management of vehicular wireless power transfer modules featuring a high volumetric power density is a major challenge. Taking into account the interaction of the electromagnetic and thermal field leads to extensive computational effort for a simulative prediction of the thermal behavior. One approach for reducing the required computational effort is the use of one-way coupled simulations. In this context, the presented paper addresses the quantitatively comparison of one-way and two-way coupled electromagnetic-thermal simulation models to predict the thermal behavior of an exemplary vehicular wireless power transfer module. The performed studies show a good consistency of the two-way coupled simulation results compared to the experimental validation, whereas the one-way coupled model predicts overall too low temperatures. Thus, two-way coupled simulation models are therefore recommended for the electromagnetic-thermal dimensioning of wireless power transfer modules for electric vehicles.

The dimensioning of wireless power transfer systems requires compliance with safety standards for human exposure and electromagnetic compatibility. For this reason, shielding is conventionally carried out with heavy and costly plates. In order to evaluate a lightweight and low-cost alternative, this paper presents a comprehensive investigation of the shielding effectiveness of metal meshes in magnetic fields of wireless power transfer systems, including analytical modeling and experimental validation. Special emphasis is laid on the validation of novel analytical approximation approaches to model the anisotropic electrical conductivity of metal meshes. The proposed approaches show good consistency of the mean value taking into account warp and weft direction, whereas the modeling of the anisotropic behavior is not sufficiently accurately represented. Using the calculated electrical conductivity, the analytical modeling of the maximum shielding effectiveness based on a literature-known approach is very consistent for the experimental validation. Thus, the performed studies provide a significant contribution to the dimensioning of metal meshes as shielding for wireless power transfer systems.

The functional and spatial integration of a wireless power transfer system (WPTS) into electric vehicles is a challenging task, due to complex multiphysical interactions and strict constraints such as installation space limitations or shielding requirements. This paper presents an electromagnetic–thermal investigation of a novel design approach for an ultrathin onboard receiver unit for a WPTS, comprising the spatial and functional integration of the receiver coil, ferromagnetic sheet and metal mesh wire into a vehicular underbody cover. To supplement the complex design process, two-way coupled electromagnetic–thermal simulation models were developed. This included the systematic and consecutive modelling, as well as experimental validation of the temperature- and frequency-dependent material properties at the component, module and system level. The proposed integral design combined with external power electronics resulted in a module height of only $15\mathrm{mm}$. The module achieved a power of up to 7.2 kW at a transmission frequency of $f_0=85\mathrm{kHz}$ with a maximum efficiency of 92% over a transmission distance of $110\mathrm{mm}$ to $160\mathrm{mm}$. The proposed simulations showed very good consistency with the experimental validation on all levels. Thus, the performed studies provide a significant contribution to coupled electromagnetic and thermal design wireless power transfer systems.

The thermal management of the vehicular module is key to the design of efficient wireless power transfer systems. In order to predict the thermal behavior by simulation, the mutual interaction of the electromagnetic and thermal fields must be taken into account. This multiphysical coupling leads to extensive computational effort. One approach to reduce the complexity by limiting the interdependencies between the domains is one-way coupling. This paper examined the applicability of one-way and two-way coupling for the prediction of the thermal management of an exemplary vehicular wireless power transfer module. The electromagnetic–thermal behavior of the proposed module was systematically studied by experiments and simulations on the component and module level. The performed studies showed that both simulation approaches accurately capture the transient thermal behavior of the coil and ferrites on the component level, whereas the one-way coupled simulation underpredicts the power losses caused by shielding by more than 20%, leading to a steady-state temperature difference of 15 K. As a result, on the module level, the two-way coupled simulation model provides a more accurate representation of the electromagnetic–thermal behavior of the proposed car pad module. Therefore, the authors recommend using a two-way coupling approach for the thermal dimensioning of wireless power transfer modules for electric vehicles.

This paper presents a systematic design approach to the development of functionally integrated mechanical-electrical lightweight systems. The development of these systems requires the end-to-end consideration of all product domains involved, aspects of lightweight design and their mutual interdependencies. To manage this complexity, a specialized approach is developed, which extends the V-model of VDI 2206 problem-specific and purpose-oriented. In line with the proposed approach, this work presents the conception and evaluation of three functionally integrated on-board receiver units of automotive wireless power transfer systems for electric vehicles. These concepts provide a significant reduction of the vertical dimensions, which significantly increases the applicability and transferability of wireless power transfer systems.