The Characteristics of the Long Length Primary Loop and the Power Supply for the SCMaglev’s DWPT System

Superconducting Maglev (SCMaglev) operates at 500 km/h, and the commercial line is currently under construction. The SCMaglev adopted a dynamic wireless power transfer (DWPT) system to supply power to on-board. The current DWPT system has been under operation in the Yamanashi Maglev Line since 2014. The DWPT system has distinctive features, long length primary loop (coil) extending over a few kilometers and a relatively lower working frequency 9.8 kHz. This paper describes the configuration of the DWPT system and compares it to other DWPT systems. Simplified methods are proposed to calculate inductance, stray capacitance, and impedance-frequency characteristics, considering both lumped and distributed circuit of the long-length loop. The calculated values are close to the measured values. The impedance changes even during power supply, and field verification clarified these changes. The reactance of the primary loop is adjusted to accommodate these changes. These theoretical and experimental verifications were conducted using actual primary loop and SCMaglev’s vehicle during the operations supplying 300 kW and running at 500 km/h.