Optimal Coupling to Achieve Maximum Output Power in a WPT System

• Published in: IEEE transactions on power electronics Vol. 31; no. 6; pp. 3994 - 3998
• Main Authors: Seo, Dong-Wook, Lee, Jae-Ho, Lee, Hyung-Soo
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-06-2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Coils; Contactless power; Coupling coefficients; Couplings; critical coupling; Electric power; Energy efficiency; Impedance; inductive power transfer; Input output; Joining; Mathematical analysis; Mathematical model; Optimization; Power amplifiers; Power generation; Power transfer; Proposals; Resonant frequency; Resonators; Simulation; system energy efficiency; Wireless networks; wireless power; Contactless power; inductive power transfer; wireless power; system energy efficiency; critical coupling
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2015.2504625

In the wireless power transfer systems, a coupling coefficient is one of the measures of performance. In particular, the coupling coefficient at critical coupling does not ensure maximum system energy efficiency but guarantee maximum output power to the load. As the coupling coefficient goes beyond the critical-coupled state, output power begins to decline. In this letter, we propose a method to maximize output power even in an overcoupled state as in the critical-coupled state by adjusting the capacitance of the resonator. Our proposal is verified by comparing the calculations and simulations with measurements, and they are in good agreement.