Design Of Automatic Impedance Matching System Based On BP Neural Network

Wireless power transfer(WPT)technology frees the electrical equipment from the restraint of the electric wire.Its flexible,efficient and convenient characteristics make it a powerful complement to the traditional electrical transmission,and has received extensive attention in many application fields.Among them,the wireless power transfer via coupled magnetic resonance technology can realize high-efficiency power transmission at a long distance and has strong anti-misalignment ability,so it has a wide range of application prospects in the fields of implantable medical equipment,wireless sensor network,electric vehicle,and etc.In practice,WPT system has the problem of power degradation when the coils are close to each other,and the cause of this problem is the system input impedance mismatch,which can be effectively solved by impedance matching.Moreover,there are uncertain factors such as random variation of transfer distance,coaxial misalignment and load impedance change,which puts high demands on the matching accuracy and speed of the impedance matching system.Therefore,this paper proposes an automatic impedance matching method based on BP neural network,which solves the dynamic impedance mismatch problem of the WPT system.Firstly,based on the circuit theory,the characteristics of the WPT system are analyzed in depth.Then,the different matching topologies are analyzed and compared,and the ?-type matching topology is finally performed.To verify the proposed method,an automatic impedance matching prototype is built.Secondly,in order to overcome the problem of slow matching speed of traditional algorithms,an automatic impedance matching algorithm based on BP neural network is proposed,and the parameters of BP neural network are optimized for accuracy and generalization ability.Furthermore,to improve the generalization ability of the algorithm,this paper also proposes an automatic impedance matching method based on adaptive network-based fuzzy inference system,which achieves a wider matching range under the premise of less influence on matching speed.To verify the proposed method,a simulation model of a WPT automatic impedance matching system based on Simulink was built.Finally,based on the simulation and prototype experiment,the effectiveness,rapidity and dynamic matching performance of the proposed algorithm are verified and compared.The results show that the simulation and experimental results were basically consistent,which proved the validity of the novel method.