Electro-thermal analysis of inductively coupled power transfer in pavement for electric vehicle charging

Inductively coupled power transfer (ICPT) system provides a promising alternative for wireless charging of electric vehicles (EVs). This study aims to develop an integrated electro-thermal analysis approach for analyzing power transmission and heat transfer of ICPT embedded in the pavement. Laboratory experiments were first conducted to evaluate wireless power transfer efficiency of ICPT system with the interference of pavement material. An integrated electro-thermal model was established to analyze transmission efficiency and temperature variation when ICPT system is embedded at various pavement depths of pavement structure subject to different vehicle offsets. The results revealed that traditional cement concrete pavement material with a typical water to cement ratio of 0.48 has negligible impact on power transfer efficiency under standard charging levels. However, the efficiency dropped from 95.4 % to 85.9 % as embedment depth increased from 4 cm to 16 cm, and it further decreased to 84.6 % with a 15 cm one-side offset at a 4 cm installation depth. The power loss results in significant changes of temperature. The maximum temperature variations were found to be impacted by incremental state of charge, charging power, and transmission efficiency, in addition to thermal properties of ICPT components. Under the most unfavorable case, those temperature changes of the ICPT system and pavement can be up to 112 °C and 76 °C, respectively.