| Wireless power transfer(WPT)technology can realize the wireless transmission of electric energy without the shackles of wires and cables,which has become the direction of research and exploration in the new century.Magnetic coupling resonance wireless power transmission(MCR-WPT)has been widely concerned because it can achieve high power transmission efficiency(PTE)in short and medium distance transmission.However,the change of transmission distance or load leads to the mismatch between the input impedance and the RF internal resistance,which will lead to the sharp decline of power transmission efficiency,and even unable to meet the normal operation requirements of some electrical equipment.In order to improve the transmission efficiency of the system,it is necessary to make the system work under the impedance of the optimal efficiency.Therefore,the efficiency is required to adapt to different distances and loads,and impedance matching is a potential research direction.In order to solve the above problems,this paper studies the traditional impedance matching method of magnetic coupling resonance wireless power transmission.The impedance matching network is designed,and an effective impedance matching control method is proposed to improve the system power and transmission efficiency.Based on the in-depth understanding of the magnetic coupling resonance wireless transmission system,the impedance matching network(IMN)of the system is mainly designed in four aspects: matching effectiveness,matching accuracy,matching speed and matching stability,so as to ensure that the whole system can be in an efficient and real-time operation state.In this paper,the traditional impedance matching method of wireless power transmission is analyzed by taking the match network of Г-type as an example.An improved match method of Г-type impedance based on Smith’s circle chart theory is proposed.The network structure of the matching method is simple,which avoids the complicated calculation process,and solves the problem of matching forbidden zone existing in Г-type impedance matching.It can effectively improve the power transmission efficiency of the system.In view of the demand of real-time regulation of the system,an adaptive impedance matching method of wireless power transmission system based on Genetic Algorithm Optimized BP neural network is proposed.Aiming at the problem of matching performance degradation caused by the inherent shortcomings of geneticalgorithm and BP neural network algorithm,the two algorithms are combined to optimize the matching network,which can achieve fast and accurate matching of wireless transmission system.Finally,a simulation platform is built in Matlab/Simulink,which is compared with a variety of existing impedance matching methods to verify the feasibility and superiority of the proposed method.Finally,the experimental platform is built to verify the designed matching method and simulation results.The experimental results show that the simulation and experimental results have good consistency.The designed impedance matching method can achieve stable and efficient power transmission of the magnetic coupling resonance wireless power transmission system,and verify the rationality of the improved adaptive matching algorithm. |
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