电动汽车无线充电的启动阶段控制策略

Start-up control strategy of electric vehicle wireless charging

针对电动汽车无线充电系统启动充电时会出现过流的异常情况,为实现系统正常启动充电,文中提出了一种新的启动阶段控制策略。该策略首先基于LC补偿结构的数学模型,分析系统在自谐振频率偏移、位置偏移及电池等效电阻变化情况下出现的过流问题;分析了系统工作频率与逆变器输出相角的关系,并基于MATLAB数值仿真得到系统的最佳工作频率范围与初始启动电压,进而设计了启动过程的PID控制器。该控制器在保证系统实现零电压切换的同时还能抑制系统启动阶段过流。开发了实验室原型机系统,并通过在一组72 V的铅酸蓄电池上的充电实验,验证了所设计控制策略的可用性及优越性。

In view of the abnormal situation that may occur over-current problems when the wireless charging system of electric vehicles start-up,in order to realize the normal start-up,a new start-up stage control strategy is proposed in this paper.Firstly,based on the mathematical model of LC compensation structure,this strategy analyzed the over-current problems of the system in the case of self-resonant frequency offset,position offset and battery equivalent change;Then,the relationship between the operating frequency of the system and the output phase angle of the inverter was deduced,and the optimal operating frequency range and initial start-up voltage of the system were obtained based on MATLAB numerical simulation,and then,the PID controller of the starting process was designed.The controller not only guarantees the system to realize zero voltage switching,but also suppresses the over-current in the start-up stage.Finally,the laboratory prototype system was developed,and the availability and superiority of the designed control strategy are verified through charging experiments on a 72V lead-acid battery.