Research On Compensation Topology And Parameter Optimization Design Of Electric Vehicle Wireless Charging System

With the increasing energy shortage and environmental pollution problems,the popularity of electric vehicles is on the agenda,and due to its advantages of safety and convenience,the electric vehicle wireless charging technology has been eagerly concerned.The magnetic induction coupled wireless charging system for electric vehicles uses electromagnetic induction to achieve non-contact transmission of electrical energy.However,due to the small coupling coefficient of its energy transmission key structure(loosely coupled transformer),the system power transmission capacity and system efficiency are low,and it is necessary to build a compensation network to improve system performance.In addition,the load changes during the operation of the wireless charging system,and the misregistration of the magnetic coupling structure may also bring about changes in the coupling coefficient,which makes it difficult to fully realize the soft switching of the inverter circuit,and further reduces the system efficiency.In view of the above problems,this paper mainly studies the compensation topology and parameter design method of the wireless charging system,and optimizes design of the compensation component parameters to achieve the inverter soft switching under a wide range of changes in load and coupling coefficient,thereby improving system efficiency.In this paper,based on the study of the basic working principle of the compensation network,by analyzing and comparing the system performance of each compensation topology,the dual LCC compensation topology with better comprehensive performance is selected to design the wireless charging system,and the parameter design method is studied.Based on the design of the loosely coupled transformer structure and resonance conditions,this paper establishes the efficiency model of the compensation network,analyzes the influence of the coupling coefficient,output voltage and compensation inductance parameters on the efficiency of the compensation network,and designs the compensation inductance parameters accordingly.In view of the problem of soft switching implementation,this paper analyzes the soft switching mode and implementation conditions of the full-bridge inverter,and analyzes the impact of the compensation component parameter changes on the system performance,and on this basis,an optimal design method of compensation capacitance parameters based on inverter soft switching is proposed.Finally,on the basis of completing the above work,this paper designs and builds a 3.3k W wireless charging system prototype,and experimental verification of the parameter design scheme.The experimental results show that using the above parameter design method,the output performance of the system basically meets the design requirements,and the system always achieves inverter soft switching under a wide range of load and coupling coefficient,and the efficiency reaches 95.2% at rated power,and when the load and coupling coefficient are reduced by half,the efficiency is still above 93%,the rationali ty and beneficial effects of parameter design are verified,and the system efficiency is improved to a certain extent.