Static and Dynamic Analysis of Wireless Power Transfer for Battery-Electric Locomotives

Wireless power transfer (WPT), particularly inductive power transfer (IPT), has been extensively researched in the electric vehicle (EV) domain due to its ability to enable automatic charging without manual intervention and its potential for charging while in motion. However, its implementation in battery-electric locomotives has not garnered sufficient attention, especially concerning the dynamic aspect. This study proposes a multi-transmitter single-receiver (MTSR) WPT system tailored for railway applications, employing a parallel synchronous multi-LCL-s compensation topology and a W-I-shaped coupler. The dynamic charging process of this system is analyzed, and methods for calculating the coupling coefficient and output during dynamic charging are derived. A prototype with one receiver and three transmitters is constructed. Static testing utilizing a single-transmitter and single-receiver (STSR) setup reveals that the system maintains a DC-DC efficiency of over 92% with an input DC voltage ranging from 200 to 500 V and an output load from 15.5 to 34 Ω. Notably, at an input power of 3.1 kW, voltage of 705V, and load resistance of 21 Ω, the system achieves a maximum efficiency of 94.73%. Dynamic testing results demonstrate that with an input power of 3 kW, voltage of 500V, and load resistance of 15 Ω, the highest dynamic efficiency reaches around 89% and remains stable at this level. Furthermore, the testing results validate the consistency between the system’s output characteristics and the calculated results, thereby verifying the rationale of the calculation methods.