The Research On Wireless Power Transmission System Based On Magnetically Coupled Resonance

Wireless power transmission technique is a technology that we can supply our electronic device without the charing cable. The power obtained from the power grid is converted to a high-frequency AC power by the signal generating circuit. And the high-frequency electrical energy radiate electromagnetic energy to the space via the antenna in the form of electromagnetic waves, the receiving terminal match with the transmission side receives electromagnetic energy in space with of the receiving antenna and convert it to electricity to a power supply for the electrical equipment.Magnetically coupled resonance technology is a type of wireless energy transmission technology, and it is proposed by a physical MIT research team in2007. It has a further transmission distance and a higher efficiency compared with the traditional electromagnetic inductive power transfer technology.We firstly study the mechanism of wireless power transmission system based on the coupled mode theory and the classical circuit model, of the transmission. A simulation using Matlab programming is established to verify the correctness of the mathematical model and come to the key point of high efficient transmission. Then we design a planar spiral coil using electromagnetic simulation software FEKO. We get the maximum radiation electric field which is about50KV/m at the frequency of18.8MHz in a distance of50cm based on the simulation of the near-field radiation electric field. A magnetically coupled wireless power transmission system is built. We measure the voltage of the50Ω load of the receive side, the peak to peak voltage is about40.5V in a distance of25cm and the voltage of transmission side is about58.7V. Calculation shows that transmission power is about8.6W and receive power is about4.2W. This shows the system can transfer about4W power t a distance of25cm with a efficiency of about50%. The frequency characteristic, distance characteristics, load characteristics, and the angle characteristics of the system is obtained by the comparative analysis method. At the end of the paper, the article summarizes the experiment concluded, and made the inadequacies of the system, and the direction of future research.