| The extensive application of electric power has greatly promoted the development of human society and unprecedentedly improved the living environment of human beings.With the progress of science and technology,the electric equipment is diversifying.The traditional wired transmission system is weak to meet the needs of some emerging fields.Magnetic coupling resonance(MCR)wireless power transfer(WPT)has a good application prospect and important research significance as possessing the advantages of high output power,high transmission efficiency,strong penetration,moderate transmission distance and high security,and has become a research hotspot.In practical application,the transmission distance may need to change in many occasions,which will have great impact on the transmission power and efficiency of the system.To solve this problem,this paper proposes a transmission efficiency improvement method,and on this basis,proposes a power efficiency simultaneous improvement method.The main work of this paper is as follows:Firstly,the mathematical model of four-coil MCR WPT system are analyzed based on the theory of mutual inductance coupling.The main factors affecting transmission efficiency and output power of the system are analyzed by using control variable method.It is found that when system parameters and coil structure are selected,the distance between excitation coil and launch coil,and the distance between receiving coil and loading coil are the decisive factors affecting output power and transmission efficiency of the system.Their optimal setting are extremely important.Then,a transmission efficiency improvement method based on Pigeon Inspired Optimization(PIO)algorithm is proposed.When the transmission distance changes,PIO algorithm is used to optimize the distance between excitation coil and launch coil,and the distance between receiving coil and loading coil.Results show that when the transmission distance changes to different values,the transmission efficiency of the system optimized by this method is significantly improved than before.The results are verified by the four-coil MCR WPT system simulation model.Besides,it is found that the output power is very low at the optimal transmission efficiency and vice versa,that is,the peak of the output power and the transmission efficiency are inconsistent.To solve this problem,a PIO output power and transmission efficiency simultaneous improvement method based on Pareto optimal is proposed.Applying this method to optimize the distances between coils,the simulation results show that no matter how the transmission distance changes in the allowable range,the output power and transmission efficiency of the system can be improved simultaneously,which greatly improves the transmission performance of the four-coil MCR WPT system.Finally,based on the experimental platform of MCR WPT system,the influence of the distance between coils on output power and transmission efficiency of the system and the two methods proposed in this paper are verified experimentally.The comprehensive verification results are well trend consistent with the theoretical analysis,which verifies the correctness and effectiveness of the methods proposed in this paper. |
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