Tethered and contactless power transfer systems for mobile devices with high reliability

Abstract

Safety-related electronics require continuous power supply even in harsh environments such as high ambient temperature, because they must operate reliably at all times. Among them, mobile devices that perform missions on the move are more difficult to be powered because of their distance from the power source. As examples of mobile devices with high reliability, this paper introduces drones to perform environmental monitoring and sliding doors of vehicles. In Chapter 1, new tethered aerial robots including roaming tethered aerial robots (RTARs) for radioactive material sampling and stationary tethered aerial robots (STARs) for environment monitoring are proposed. The load power, power type, operating frequency, and flight attitude of the RTAR and STAR were 180 W, AC 100 kHz, 20 m and 300 W, AC 100 kHz as well as DC, 80 m, respectively. In Chapter 2, a sliding EE transformer (SEET) rail, which has a strong and independent magnetic coupling to the gap variation between the transmitter (Tx) line and receiver (Rx) coil for powering the sliding door, is newly proposed. Through detailed coil designs based on electric and magnetic circuit analyses, design constraints on voltage, output power, flux density, and zero voltage switching are proposed with a closed form solution of output voltage and theoretical maximum output power. The SEET rail is successfully designed and optimized to provide a maximum load power of 200 W for the sliding door within an ambient temperature range from -40℃ to 125℃ by following design constraints. The proof-of-concept prototype shows a strong magnetic coupling , κ = 0.76 at 20℃. The maximum power transfer efficiency excluding the regulator was 85% at a nominal load power of 100 W, and the efficiency at the maximum load power of 200 W was measured as 82% with a 3%P variation by the temperature variation.