Consideration of RMS Envelope Control for Wireless Power Transfer System

Wireless power transfer system used in Superconducting Maglev employs power control based on the envelopes of root mean square (RMS) values. The control aims to stabilize the power supply between the ground and on-board systems. To evaluate stability under various conditions, mathematical models are required. In particular, representing approximate RMS envelope with a transfer function is challenging. This paper we propose a simplified method to derive a transfer function with complex coefficients and certain modifications. As a result, the calculated transient response of the circuit to a step voltage input closely matches the measured response. Additionally, stability criteria based on the complex coefficient transfer function are introduced.