Efficiency analysis of 13.56MHz flexible wearable electronic Magnetically coupled resonance wireless energy transfer

Looking for a new growth point for the improvement of the efficiency of the 13.56MHz magnetic coupling resonance wireless energy transmission system, this paper takes the energy transmitting part, the coupling system, the energy receiving part and the load as the research objects, and analyzes the transmission efficiency of each part. The efficiency expression of each part is obtained by deduction, and finally the efficiency expression of the whole system is obtained. By analyzing the expression of the entire transmission efficiency, the factors that affect the system transmission efficiency are obtained, including load impedance, system frequency, coil diameter, coil radius, number of coil turns, coil position, transmission distance, coil coupling efficiency, Coil quality factor, load matching, etc. The effects of the coupling coefficient (k) of the coupling coil and the load on the system efficiency are analyzed emphatically. Through the analysis, it can be obtained: (a) under the condition of a certain load, the system efficiency increases with the coupling factor, and tends to be stable finally, and the stable value of the system efficiency increases with the increase of load; (b)when the k is small (<=0.15), the system efficiency increases rapidly at first and then decreases slowly with the increase of the load, and the magnitude of the decrease gradually tends to moderate as the coupled system increases. When the k exceeds 0.15, the system efficiency first rapidly increases and then tends to be stable with the increase of the load. According to the various influencing factors obtained from the theoretical analysis, the effect of these factors on the efficiency is verified by simulation software, so as to optimize the relevant parameters, which provides a theoretical basis for improving the efficiency of the magnetic field resonance coupling wireless energy transmission system.