| MCR-WPT technology has been developed quickly in recent years because of its high transmission efficiency,low environmental and safety hazards,and medium transmission distance,which shows that there is a great potential for wireless power transmission technology in the future.Although many scholars had made a lot of related research and acquired a series of fruitful results,the most basic and critical problems of the whole system have not been solved or even rarely mentioned,that is the power-efficiency synchronization of system.Author's research group is dedicated to studying the maximum power of system with the maximum efficiency,i.e.the power-efficiency synchronization.In order to realize the optimal transmission of WPT system,including the overall output power and efficiency of the magnetic coupling transmission subsystem and its high frequency power supply system reach the maximum synchronously.To deal with the thorny problem,this paper firstly analyzed the SS topology system by using the mutual inductance theory of concentrated parameters,and proposed the concept of power-efficiency synchronization factor,and summarized its realization prerequsites.In the case of efficiency synchronization factor ?=1 and ??1,the relationship between transmission efficiency and power versus load is analyzed by Math CAD simulation software,and the probability of system synchronization state is verified.In addition,the synchronization theory is also suitable for the non-pure resistive load.Research results of SS show that this system can make efficiency and load power raising simultaneously,but the power-efficiency synchronous load and its effective load are small and not to fit with the larger load.In order to improve the synchronous load and its effective load of the system,then the SP structure is researched.It is found that the system parameters satisfies ?C2RL=1 can greatly simplify the system analysis process during the process of modeling and analysis.The effect of synchronous load and effective load are improved by comparing with the SS system,but its transmission efficiency and power is reduced.Considering that the intermediate coil can effectively improve the transmission efficiency of the two-coil structure system,the performance of the single intermediate coil system is analyzed.The results show that the system can also achieve the same effect,and the transmission efficiency and power of the system are improved.Therefore,this system are more suitable for larger loads.In addition,through the analysis of the factors affecting the optimal frequency of system synchronization,the effectiveness of related theory is further certified.In order to make the system get higher transmission efficiency and power,the Class-E power amplifier is finally selected as the system power source by comparing different power amplifiers.Finally,the synchronization theory of SS structure and single intermediate coil system were experimentally verified.Research results indicate that the SS system realized synchronization when the working frequency is 1.312 MHz,the efficiency is up to 86.7% and the power is 4.01 W.The transmission efficiency of the single intermediate coil system is about 89.5%,the power is 4.31 W,and the synchronization load is about 64.8 ?. |
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