一种考虑电池自身特性的电流源型充电系统

A Current-Source Charging System Considering the Characteristics of Battery

基于三相电流源型整流器(CSR)提出一种考虑电池内部特性的快速充电系统,包括变恒流(VCC)与恒压(CV)两种充电模式。针对VCC模式,引入电池二阶Thevenin电路模型,并根据实验数据构建电池在不同充电电流下的极化电压与SOC的关系曲线;将极化电压及其变化率作为输入量,利用模糊控制器推导出下一时刻的参考充电电流;当电池电压升至截止电压时,系统转为CV模式。针对两种控制模式,基于电压定向建立具有功率因数延迟角自调节能力的间接电流控制策略。在频域内,借助Matlab/SISO设计工具,对电流内环、电压外环控制器参数进行优化配置。最后,通过仿真与实验验证了所提方法的正确性与可行性。

A novel fast-charging strategy considering the battery inner features is developed based on a three-phase current-source rectifier （CSR）, including a variable constant current control scheme and a constant voltage control scheme. Regarding the VCC mode, a second-order Thevenin equivalent circuit is used to model the dynamics of LiFePO4 battery. Subsequently, according to the experimental data, the polarization voltage curves versus the states of charge （SOC） are established at different charging currents. On this basis, the polarization voltage and its change rate are considered as the input variables of the fuzzy control algorithm, so the reference charging current in the next instant can be deduced. Then, the VCC mode is switched into the CV mode once the cut-off voltage is reached. For the two modes above, a voltage-oriented CSR indirect current control strategy is proposed, in which a delay-angle of power factor is introduced into modulation signal. By using Matlab/SISO design tool in frequency domain, the parameters of current inner-loop and voltage outer-loop controllers are optimized. Finally, simulation and experimental results verify the correctness and availability of the proposed strategy.