Design of Wireless Power Supply System for Trackless Trolley Car

In this paper, a new method to design a wireless power supply system for trackless trolley car is proposed. Electric field resonant Wireless power transfer (WPT) technology is a method for WPT, which releases a high-frequency electric field in the air. Any conductor, with the same resonant frequency as the frequency of electric field, would receive power with the highest efficiency. For one emitting device, electric field released by the device is centrally symmetric in the air. Based on that, a wireless power supply system is designed for movable devices such as trackless trolley car. Working principle of the system is studied in this paper including analysis of lumped parameter circuit and electromagnetic field model. Two Tesla coils are made for system design and experimented. As a result, this system can transfer power as 18W with efficiency of 15% within a radius of 1.2m. There are some more extra experiment such as quasi-single-wire power transfer and detection of electric field in the air.