摘要
针对汽车向用户供电(V2H)时,由于负载不平衡引起的母线电压振荡、电流不平衡等问题,设计适用于工作在V2H模式下的车载三相四线双向充电器。采用分裂电容并结合中线桥臂作为负载不平衡时中线电流的回路,以抑制因负载不平衡引起的分裂电容两端电压振荡问题。首先分析不平衡负载下分裂电容两端电压振荡的根本原因,给出不同的不平衡负载下分裂电容容值的选择依据,并通过仿真验证了理论分析的正确性。在此基础上,结合中线桥臂与拓扑电路的等效模型,提出与其他三相完全解耦的中线控制方法,保证了不平衡负载下分裂电容端电压及三相输出电压的稳定。同时给出在V2H模式下系统启动过程中的隐患,提出通过调节PWM死区时间的方法实现了系统软启动,进一步提高系统的可靠性。最终采用双有源桥与三相四线逆变器级联完成了10kW的V2H样机,不平衡负载由切换纯电阻负载模拟完成,实验数据与仿真值匹配,验证了所提方案的有效性。
In view of the oscillated bus voltage and imbalanced current distribution caused by imbalanced load condition at vehicle to home(V2H)mode,this paper proposed a 3-phase 4-wire on-board bidirectional charger operating at V2H mode.Split DC-link capacitor is utilized with a neutral leg which provides a path for the zero-sequence current.Switches of the neutral leg are controlled to solve the problem of DC-link voltage oscillation.Firstly,the fundamental reason of the DC-link voltage oscillation under imbalance load is analyzed,and the selection guidance of DC-link capacitance for different imbalance loads is provided.A simulation model is introduced to verify the theoretical analysis.Based on the neutral leg and equivalent model of topology,a control method that is decoupled from others three phases is proposed to ensure the stability of output voltage and suppress voltage oscillation of DC-link capacitor.Meanwhile,this paper indicates the risks of system starting under V2H mode and introduces soft starting method by adjusting PWM dead time to enhance reliability of the system.Finally,the dual active bridge(DAB)is connected with 3-phase 4-wire inverter to deliver a 10 kW V2H prototype.Imbalanced loads are simulated by switching resistance loads.The experimental results match the simulation results,which verifies the effectiveness of the proposed scheme.
作者
付永升
李静
胡文婷
雷鸣
Fu Yongsheng;Li Jing;Hu Wenting;Lei Ming(School of Electronic Information Engineering Xi’an Technological University,Xi’an 710021 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2019年第24期5176-5188,共13页
Transactions of China Electrotechnical Society
关键词
双向充电器
V2H
三相四线逆变器
分裂电容
中线桥臂
双有源桥
死区时间
Bidirectional charger
V2H
3-phase 4-wire inverter
split DC-link capacitor
neutral leg
dual active bridge
dead-band
