三相LCL/P补偿无线充电系统设计与建模分析

Design and modeling analysis of three-phase LCL/P compensated wireless charging system

针对无线充电系统磁耦合机构补偿元件的谐振电压高、谐振环流大以及磁感应强度高的问题,该文研制一种基于三相逆变器和三相LCL/P补偿的无线充电系统。首先通过仿真对比分析传统单相无线充电系统和三相无线充电系统的特性,在此基础上推出三相逆变器的开关周期平均理论模型,提出电路的闭环控制策略。理论与仿真分析表明:与单相补偿结构的无线充电系统相比,该文研制的三相无线充电系统补偿元件电压、电流是同样功率等级单相电路的1/3~1/2,原边线圈的磁感应强度是同样功率等级单相电路的1/3以下;在负载相同的条件下,三相逆变器每个开关管承受的电流相当于单相全桥逆变器开关管承受电流的2/3,电流路径中开关管导通电压下降1/3;将两级控制系统简化为单级闭环控制系统,可提高电路的稳定性和可靠性。最后,根据上述原理搭建2 kW无线充电系统样机,从直流电源到负载的传输效率达到95%,通过实验可证明该文所述电路结构与原理分析的有效性与准确性。

Aiming at the problems of high resonant voltage,large resonant circulation and high magnetic induction intensity of the compensation element of the magnetic coupling mechanism of the wireless charging system,a novel wireless charging system based on three-phase inverter and three-phase LCL/P compensation is developed in this paper.Firstly,the characteristics of traditional single-phase wireless charging system and three-phase wireless charging system are compared and analyzed through simulation.On this basis,the switching period average theoretical model of three-phase inverter is deduced,and the closed-loop control strategy of the circuit is proposed.The theory and simulation analysis show that compared with the wireless charging system with single-phase compensation structure,the voltage and current of the compensation element of the three-phase wireless charging system developed in this paper are 1/3-1/2 of the single-phase circuit with the same power level,and the magnetic induction intensity of the primary coil is less than 1/3 of the single-phase circuit with the same power level.Under the condition of the same load,the current borne by each switch tube of the three-phase inverter is equivalent to 2/3 of the current borne by the switch tube of the single-phase full bridge inverter,and the on voltage of the switch tube in the current path decreases by 1/3.The two-stage control system is simplified into a single-stage closed-loop control system,which improves the stability and reliability of the circuit.Finally,according to the above principle,a 2 kW wireless charging system prototype is built,and the transmission efficiency from DC power supply to load reaches 95%.Experiments show the effectiveness and correctness of the circuit structure and principle analysis described in this paper.