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1. Background

Maxwell’s equations explain how electric and magnetic fields are generated and altered by each other. The equations form a foundation of today’s wireless communication technologies. Compared to the signal energy in communication, a much large amount of energy can be propagated in space actually base on a same physics, i.e. the wireless power transfer (WPT). In recent years, due to a dramatic need in charging of various electronic devices (e.g. cellphones, laptop computers, tablets, medical implant devices, etc), it is obviously desired by users to have a ubiquitous access to both information and electrical power through air. For the devices and systems that require large power, such as robots and electric vehicles, WPT not only provides a convenient and safe non-contacting charging, but also opens a new direction in on-board energy and power management. Besides, it is especially significant that WPT provides a viable solution without the need of dramatic improvements in battery technology.

Despite various technologies, all the WPT systems share a similar configuration including a power source, a coupling system, a rectifying circuit, a power regulating, and charging management circuit (such as a dc-dc converter) and a load. For such a system, besides an optimized design of each circuit, a system-level analysis and optimization is important that serves as a basis for the following design and control efforts. 
2. Interests (please refer to our publications for details)

  • Conponent- and system-level design, optimization, and control for high performance WPT systems
  • Modeling, analysis, and compensation for multiple-receiver WPT systems 
  • Autonomous and intelligent power distribution in wireless networked energy systems

3. Platforms

  • 13.56-MHz WPT system for optimal load tracking (Fig. 1)
  • High efficiency 6.78-MHz WPT system using a Class E rectifier (Fig. 2)
  • Multiple-receiver 6.78-MHz WPT system (Fig. 3)

Fig. 1. The experimental 13.56-MHz WPT system for optimal load tracking. (a) Overall system. (b) Relative position of coils. (c) Power sensor. (d) I/V sampling board. (e) Cascaded DC/DC converter.


Fig. 2. A high-efficiency 6.78-MHz WPT system using a Class E current-driven rectifier (84% dc-dc efficiency under a 20 W power level and a loosed coupling, mutual inductance coefficient k=0.1327).

Fig. 3. A multiple-receiver 6.78-MHz WPT system for investigating the modeling and the decentralized power distribution among multiple receivers.