Frequency Decrease Analysis of Resonant Wireless Power Transfer

• Published in: IEEE transactions on power electronics Vol. 29; no. 3; pp. 1058 - 1063
• Main Authors: Zhang, Yiming, Zhao, Zhengming, Chen, Kainan
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Capacitors; Coils; Comparative analysis; Decreasing frequency; Electrical engineering. Electrical power engineering; Electrical power engineering; Energy efficiency; Equivalent circuits; Exact sciences and technology; Frequencies; Inductance; magnetic resonance; Power networks and lines; Power supply; Q-factor; quality factor; Resistance; Resonant frequency; transfer efficiency; Users connections and in door installation; wireless power transfer; Q factor; Magnetic resonance; Power transmission; Wireless electricity; Transfer coefficient; Experimental study; transfer efficiency; quality factor; Resonance frequency; High efficiency; Frequency analysis; Transfer factor; Decreasing frequency; wireless power transfer; Mathematical simulation; Energy transfer; Comparative study
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2013.2277783

Recent years have witnessed the booming development of resonant wireless power transfer (RWPT). Compared with conventional inductive power transfer, the frequency of RWPT is usually much higher. To reduce the resonant frequency while maintaining the transfer efficiency constant at the same transfer distances, two solutions are proposed and realized in this letter. Two fundamental structures for RWPT are analyzed and the expressions of the transfer efficiency are deduced. It is pointed out that the transfer quality factor and the load matching factor are two important factors of achieving high transfer efficiency. The larger the transfer quality factor, the higher the transfer efficiency. There is an optimal load matching factor to reach the highest transfer efficiency. The transfer efficiency can remain constant at the same distances if the transfer quality factor is kept at the same level and the load is matched. Theoretical calculations and experimental results provide a sound basis for decreasing frequency.