| Wireless power transfer(WPT)technology is a technology based on Faraday principle to realize non-contact radio energy transmission.It has excellent characteristics of safety,reliability,green and environmental protection,and is widely used in consumer electronic products,household intelligent appliances,biomedical electricity,electric vehicle industry and other related fields.At present,in the research of inductive Wireless power transfer(WPT)technology,a systematic and in-depth study has been carried out based on the constant resistance load.But in the application of wireless power transfer system,the load may be resistive,resistive and inductive,or resistive and capacitive.For a designed and assembled wireless power transfer system,the change of load may lead to the change of resonant frequency of the system,the difference of resonant frequency on both sides of the system,the change of the best matching load of the system,and the decrease of the transmission characteristics of the system.In this paper,the effects of different load types on the transmission characteristics of basic topology and compound topology wireless power transfer systems carried on research,and put forward the method of improving transmission performance.The main research work and innovations of this article are as follows:(1)Influence of resistance load variation on transmission characteristics.The expressions of resonant frequency,transmission power and transmission efficiency of wireless power transfer system with basic topology and compound topology are derived,and the influence of resistance load change on the transmission characteristics of the system is analyzed by simulation.(2)Influence of resistive and resistive capacitance load changes on transmission characteristics.The expressions of resonant frequency,transmitted power and transmission efficiency of basic topology and compound topology wireless power transfer systems are derived when resistive inductance and resistive capacity load are varied,and the influence of resistive inductance and resistive capacity load on transmission characteristics is simulated and analyzed.(3)Optimization design of resonant network parameters for wireless power transfer system based on genetic algorithm.The NSGA-Ⅱalgorithm based on target can model the LCC radio energy transmission system,selects transmission power and transmission efficiency as objective function.It also gave the limit function and the parameters and their range to realize the optimal design of resonant network parameters.(4)Resonant network tuning method of wireless power transmission system based on phase-controlled switched capacitors.In order to improve the transmission power and transmission efficiency,the phase-controlled capacitor tuning method is adopted to adjust the compensation capacitor according to the load changes,so that the resonant frequencies on both sides of the system are the same and the working frequency is close to the resonant frequency of the system when the load changes.(5)An experimental prototype of the wireless power transmission system LCC topology with the rated power of 200 W was built,and the proposed system parameters are optimized and the transmission characteristics of the system are verified by simulation and experiment.The results show that the research method proposed in this paper is correct. |
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