Development of Wireless Power Transmission System for Transfer Cart with Shortened Track

In this study, a wireless power transmission (WPT) system for high power was developed to supply the wirelessly powered transfer cart for a clean environment (such as liquid crystal display (LCD), semiconductor, and flat panel display (FPD) device industries) to improve the cleanliness of related industrial production lines and save energy. The power transmission method of WPT and the core design were optimized, and a shortened track was fabricated to enable WPT via short power lines for diverse applications in a small space-constrained workshop. In realizing the shortened Litz wire system, the amount of heat generated increased due to the increased resistance in the system, and efforts were made to improve the thermal performance. A simple approach was also proposed to estimate the skin depth caused by the skin effects in a cable made up of multiple strands of multiple wires, validated through thermal analysis by using ANSYS software in terms of heat generation by an electric field. Structure designs were implemented to improve the heat transfer performance, and the experimental results of WPT systems at a power level of 21.54 kW demonstrate that the power transfer distance of WPT was above 15 mm with a charging efficiency above 83.24%.