Wireless Power Transmission and Drives Based on Maxwell's Displacement Current Schematic of Portable, Wearable Electronic Devices
Energy is the foundation of today's society and an important indicator of the quality of human life.Electric power is always transmitted efficiently, safely and accurately through metal wires / cables since the first use of electricity.As a fuel for fossil fuels, nuclear energy, hydro power , The electromagnetic induction power generation technology relies on the flow of Lorentz force-driven free electrons in the metal wire.In order to meet the energy requirements of mobile electronic products, Internet of things and sensor networks, it is very important to realize the wireless transmission of electric energy, Especially for implantable medical devices, security, radio frequency identification, etc. At present, wireless power transmission technology is usually based on induction coils and / or antennas.Wireless charging technology is widely used in wireless devices and systems Adaptability and mobility is very important.Although there are three electromagnetic induction, magnetic resonance and radio waves wireless charging technology model, but these technologies are still quite complex and inefficient.
In 1861, the British scientist Maxwell proposed the Maxwell's equations, the first system of equations in physics, and introduced the notion of displacement current boldly and innovatively in the system of equations. Maxwell's displacement current is different from the conventionally observed free-electron-conducting currents, Is due to the time-varying electric field coupled with the minute movement of the atom-bound charge and the dielectric polarization in the material over time.The first term of the displacement current unifies the electric and magnetic fields and predicts the presence of electromagnetic waves and establishes a wireless communication Of the physical basis.The second displacement current was found to be the fundamental theoretical basis and source of nano-generator, has important potential applications in wireless power supply.The theoretical origin of nano-generator and the traditional electromagnetic generator is essentially different from the electromagnetic The generator uses a changing magnetic field to generate electric current and adopts the mechanism of resistive free electron conduction driven by Lorentz force. The nanogenerator uses the change of polarization field caused by surface polarized charge to generate electricity, adopts the mechanism of capacitive displacement current The nano-generator is Maxwell's displacement current following the theory and technology of electromagnetic waves Another major application of energy and sensing will affect the future development of technologies such as the Internet of Things, sensor networks, blue energy and big data.
Recently, Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing Institute of Nano Energy and Systems, Chief Scientist Wang Zhonglin, Beijing Institute of Nano Energy - Beijing University of Science and Technology professor Cao Xia double hiring, and Beijing University of Science and Technology Wang Ning research team, carried out based on Maxwell displacement current from Driven wireless power transmission research.The team has long been engaged in micro and nano energy and nano-generator research work, thanks to the accumulation of research work, combined with the phenomenon of frictional electrification observed in life, the first proposed Maxwell displacement current applied to The idea of wireless power transmission is further designed with a contact-sliding rotating generator with a grid structure and a flexible wearable generator. The external mechanical driving / stimulation causes the polarization charge distribution and the spatial electric displacement field to change periodically with time , Resulting in displacement current.These generators wirelessly collect the mechanical energy in the surrounding environment by the principle of displacement current and can sustainably supply various portable and wearable electronic devices.The wireless power transmission technology is a low frequency<5Hz) 下的能量传输提供了更有效的方法. 相关研究成果发表在Advanced Materials上.
