Toward an Inductively Powered Wearable Heater using Conductive Thread Coil

In this paper, inductive power transmission (IPT) system with wearable heater is proposed to improve convenience for users. The conductive thread which has high electrical resistance is utilized for a receiver (Rx) coil in a clothing to generate high temperature with low current. We introduced series-none (SN) topology to eliminate a resonant capacitor in the wearable heater. The proposed wearable heaters are totally washable thanks to its non-metallic materials other than conductive threads on the clothing. Single resonant capacitor in a transmitter (Tx) is implemented for resonating both Tx and Rx, resulted in the increased power delivered to the load (PDL) while maintaining a high-power transfer efficiency (PTE) comparable with a conventional series-series (SS) topology. When supply voltage of power amplifier, VDD, is 7 V, while the PTE of SS mode and SN mode was 85.2% and 75.8% respectively, the PDL of SS mode and SN mode was 2.74 W and 4.6 W respectively.