Reduction in Human Interaction with Magnetic Resonant Coupling WPT Systems with Grounded Loop

Abstract

Wireless power transfer (WPT) systems have attracted considerable attention in relation to providing a reliable and convenient power supply. Among the challenges in this area are maintaining the performance of the WPT system with the presence of a human body and minimizing the induced physical quantities in the human body. This study proposes a magnetic resonant coupling WPT (MRC-WPT) system that utilizes a resonator with a grounded loop to mitigate its interaction with a human body and achieve a high-efficiency power transfer at a short range. Our proposed system is based on a grounded loop to reduce the leakage of the electric field, resulting in less interaction with the human body. As a result, a transmission efficiency higher than 70% is achieved at a transmission distance of approximately 25 cm. Under the maximum-efficiency conditions of the WPT system, the use of a resonator with a grounded loop reduces the induced electric field, the peak spatial-average specific absorption rate (psSAR), and the whole-body averaged SAR by 43.6%, 69.7%, and 65.6%, respectively. The maximum permissible input power values for the proposed WPT systems are 40 and 33.5 kW, as prescribed in the International Commission of Non-Ionizing Radiation Protection (ICNIRP) guidelines to comply with the limits for local and whole-body average SAR.

Mutual and Self-Inductance Variation in Misaligned Coupler of Inductive Power Transfer System: Mechanism, Influence, and Solutions

“…Inductive power transfer (IPT) technology is a relatively mature form of wireless power transfer, which has significant advantages in terms of safety, convenience, and economy compared with traditional contact power transmission. It has been heavily researched and applied in electric vehicle charging [1][2][3], intelligent household appliances [4], implantable devices [5,6], and railway transportation [7]. However, in practical usage scenarios, the inevitable misalignment of the couplers of IPT systems introduces serious problems, such as increased switching losses of the inverters and fluctuations of the system output, which severely affect the safety and stability of power transmission.…”