Segmented IPT Coil Design for Continuous Multiple Charging of an Electrified Monorail System

Abstract

Inductive power transfer (IPT) systems based on segmented transmitter (Tx) coils are newly proposed in this article. These IPT systems can deliver wireless power to multiple transport robots in an electrified monorail system (EMS) for continuous transportation missions. Considering the one-dimensional long-line driving characteristics of the transport robots having receiver (Rx) systems, a segmented Tx coil structure is introduced so that flexible Tx installation, easily Tx coil fabrication, and insensitive IPT characteristics are possible. In this case, in order to remove the magnetic dead-zones at the adjacent sections between the adjacent Tx coils, folded Tx coils, and an optimally sized Rx coil are applied to the proposed IPT system in this article. Thus, continuous wireless powering to multiple transport robots in the EMS and flexible extending of the Tx length are possible by the proposed IPT systems. For the soft-switching operations of the proposed IPT systems, a gyrator-based static circuit modeling is presented in order to select an appropriate resonant capacitance. By the proposed gyrator-based circuit analysis, it is found that high efficiency Tx circuit operation can be achieved, regardless of the number of Rx and the load conditions. The proposed segmented multiple Tx systems and the 30 W Rx systems for the transport robots were fabricated and verified by experiments for various operating scenarios. Compared with the conventional 2-m-long Tx coil having 69.1% dc power efficiency, the two-segmented 1-m-long Tx coil systems have no powering dead zone and achieved 74.2% dc power efficiency for one 30 W Rx system. As a result, the proposed two segmented 1-m-long Tx systems have 5.1% higher dc efficiency than the conventional 2-m-long Tx coil under the 2-m-long driving route in EMS application.