Research On Efficiency Optimization Method And Key Technology Of Magnetically Coupled Resonant Wireless Power Transfer System

With the continuous development of science and technology,people have higher and higher requirements for power transmission systems.In many applications,traditional contact power transfer technology cannot solve the practical problems.For example,in the field of equipment logistics support such as the Internet of Things and embedded sensing,how to continuously supply power to a large number of distributed sensor nodes is still a major problem.In recent years,magnetically coupled resonant wireless power transfer(WPT)technology has developed rapidly,which provides a new way to solve the above problems.However,in order to realize the further promotion and application of this technology,there are still a lot of basic problems to be solved in the analysis,design and optimization of the WPT system.This paper focuses on the key theoretical and technical issues faced in the practical applications of the magnetically coupled resonant WPT technology.The main research contents include:(1)A modeling method combining the lumped parameter circuit and the two-port network is proposed to model the WPT system: Firstly,the WPT system is divided into several sub-parts to be modeled separately,and then the models of each sub-part are combined to get the model of the entire WPT system.This model has simple form and good applicability,and can provide an effective analysis tool for the characteristic analysis,parameter design and efficiency optimization control of the WPT system.(2)The transmission characteristics of the magnetically coupled resonant WPT system are deeply analyzed.Its resonance and impedance matching mechanism are revealed.The conditions for achieving the maximum transmission efficiency and the maximum power gain are obtained.The frequency splitting phenomenon of the WPT system is analyzed,and the theoretical calculation formula and existence condition of the split resonance frequencies are derived,which has important guiding significance for the analysis and optimization design of WPT system.(3)The uncertain optimization design method of the magnetically coupled resonant WPT system is studied in depth: Firstly,the influences of uncertain parameter changes on the transmission efficiency and the power gain of the WPT system are analyzed.Then an uncertain optimization method based on the interval number optimization theory is proposed to obtain the optimal solution of the design vector of the WPT system.Finally,experiments are carried out to verify the proposed uncertain optimization method of the WPT system.The experimental results show that the proposed method can significantly enhance the transmission performance and robustness of the WPT system under uncertain parameter variations.Therefore,the proposed method has important theoretical and engineering application value.(4)Two adaptive impedance matching methods for the magnetically coupled resonant WPT system are proposed,including dual-side impedance-transforming method,and frequency-tracking and impedance-transforming combined method.The working principle,impedance matching algorithm and system design scheme of two adaptive impedance matching methods are deeply studied.Finally,experiments were carried out to verify the proposed adaptive impedance matching methods.The experimental results show that the dual-side impedance-transforming method can make the WPT system maintain the highest power gain when the parameters change.The frequency-tracking and impedance-transforming combined method can make the WPT system maintain high power gain when the parameters change,and at the same time,the structure of the receiving circuit of the WPT system can be simplified.Therefore,the proposed adaptive impedance matching methods have important practical value.In summary,this paper focuses on the key theoretical and technical issues that urgently need to be solved in the practical applications of the magnetically coupled resonant WPT technology.The modeling method and transmission characteristics of the WPT system are further studied.The influences of the uncertain parameter changes on the WPT system are analyzed.Then,the uncertain optimization design method and the adaptive impedance matching methods are proposed to overcome the influence of uncertain parameter changes on the WPT system.Through the proposed methods,the transmission performance and anti-interference ability of WPT system are significantly improved.These research results can provide theoretical basis and technical support for the further application of the magnetically coupled resonant WPT technology.