电动汽车复合电源的能量控制系统研究

摘要

电动汽车的动力电源要同时具备高能量密度和高功率密度的特点,单一的动力电源很难满足要求,蓄电池比能量大的特点和超级电容比功率大的特点具有很强的互补性.该文通过双向半桥DC/DC变换器将蓄电池和超级电容连接到直流母线上构成电动汽车复合电源系统.利用超级电容能瞬时大电流充放电的特点,研究了以负载功率的变化速率为判断依据的功率分配方法.这样将减小蓄电池的瞬时充放电电流,有效抑制负载变化时对直流母线造成的冲击,实现复合电源能量的最优分配.通过Matlab/Simulink仿真验证了系统控制策略的有效性.%The power supply of electric vehicles should have the characteristics of high energy density and high power density.It is very difficult for a single power supply to meet those requirements.Fortunately,the characteristics of high energy density of battery and high power density of ultra-capacitor are highly complementary.In this paper,the battery and ultra-capacitor are connected to the DC bus of composite power system of electric vehicle through the bidirectional half bridge DC/DC converter.Utilizing the large instantaneous current characteristic of ultra-capacitor in charging and discharging,a new power allocation method according to the rate of change of the load power is proposed.It is foreseeable that the instantaneous charging and discharging current of the battery will be reduced and the impact of the load on the DC bus will be suppressed if the proposed power allocation method is implemented.Finally,the effectiveness of the proposed control strategy is verified by Matlab/Simulink simulation.