| Wireless power transmission is an energy transmission method that can load energy onto electromagnetic fields,electromagnetic waves,or mechanical waves to achieve non-contact propagation in space.Compared with the traditional cable power transmission mode,wireless power transmission has the characteristics of flexibility,convenience,and strong applicability,and has become a research hotspot in the field of energy transmission.At present,there are three main transmission methods for wireless power transmission: magnetic induction coupling,magnetic coupling resonance,and microwave radiation.Among them,magnetic coupling resonance wireless power transmission has the advantages of high transmission power,long transmission distance,and safe and no radiation.An important development direction in the field of wireless energy transmission in the future.Magnetically coupled resonant wireless power transmission is largely dependent on the magnetic flux connection between the transceiver coils.At the same time,The distance,deflection angle and offset distance between the coils will directly affect the magnetic field distribution between the transceiver coils.In some cases,the magnitude of the load resistance also affects the degree of magnetic field coupling.Therefore,the transmission power of the magnetic coupling resonance wireless power transmission fluctuates greatly when the above parameters change,and stable transmission of power cannot be achieved.Based on the above background,this thesis starts from the basic principles and structure of magnetically coupled resonant wireless power transmission,and studies its transmission power performance.The main work content and innovations of this article are as follows:(1)Taking the dual-coil system as the starting point,this thesis mathematically analyzes and models the mutual inductance coupling phenomenon between the two coils,and derives the concept of reflection impedance.At the same time,the characteristics of three kinds of resonant circuits are analyzed and compared,and the series resonant circuit is selected as the resonant circuit of the system design.Finally,the dual-coil system and the series resonance circuit are combined into a magnetically coupled resonant wireless energy transmission system,and the conditions for maximizing the transmission efficiency of the system and the factors affecting the transmission power are deduced.A stable transmission using a transformer array to transform the reflection is proposed.Power scheme.(2)This thesis briefly analyzes the advantages and disadvantages of three kinds of common transmission coils,and combined with the characteristics of magnetic coupling resonance wireless energy transmission system,selects a vertical spiral coil as the transceiver coil.Then according to the theoretical analysis,the relationship between the self-inductance and loss resistance of the vertical spiral coil and the coil parameters such as the length,radius,number of turns and winding wire diameter of the coil is mainly studied.The necessity of the coil size being limited is proposed.The condition of maximizing efficiency is to design the transceiver coil in this thesis.(3)Design a peripheral auxiliary circuit with power detection,information processing and control feedback functions,so that it has the ability to automatically stabilize the transmission power in real time when the transmission power of the system changes.The standard deviation of the transmission power in the power stable area was reduced from 3.14 to 0.66,and the standard deviation of the transmission power under load changes was reduced from 3.90 to 1.18.In the end,this article performs physical processing on the above design and completes the experiment.The actual data measured the standard deviation of the transmission power of the system designed by this article under the change of transmission parameters and the change of load impedance to about one-third of the original.This result proves The correctness and feasibility of this article’s design ideas are presented. |
