基于模糊逻辑的电动汽车双源混合储能系统能量管理策略

Energy management strategy of a dual-source hybrid energy storage system for electric vehicles based on fuzzy logic

针对电动汽车行驶过程中电池放电电流过大导致的电池容量衰减问题,构建了由锂离子动力电池、超级电容和多端口DC/DC变换器构成的全主动式混合储能系统,其中电流环控制器和电压环控制器分别控制输出电流和直流母线电压。结合超级电容SOC、整车需求功率和车速情况,根据建立的45条模糊控制规则,模糊逻辑控制器调节锂离子动力电池和超级电容的充放电功率,在车辆峰值功率需求较高时避免了高频电流波动对动力电池寿命的影响。同时在功率需求较低时,动力电池给超级电容充电。在HWFET工况下的实验结果表明所提出的全主动式双能量源混合储能系统和基于模糊逻辑的能量管理策略能够有效保护锂离子动力电池免受大电流波动影响,从而达到延长电池寿命的作用。

Capacity attenuation of power battery is a problem caused by excessively high discharge current during electric vehicle driving.Thus a fully active hybrid energy storage system composed of a lithium-ion power battery,a supercapacitor and multi-port DC/DC converter is constructed,where the current and voltage loop controllers are responsible for the controlling of output current and DC bus voltage,respectively.Then taking the supercapacitor SOC,vehicle demand power and vehicle speed as input variables,and lithium-ion power battery output power as the output variable,a fuzzy logic-based energy management strategy for an energy storage system is proposed by constructing 45 fuzzy rules.The charge and discharge power of the lithium-ion battery and supercapacitor are adjusted by the fuzzy logic controller,which ensures the peak power demand of the vehicle during starting and acceleration,and avoids the impact of high-frequency current fluctuations on the life attenuation of the power battery.When the power demand is low,the power battery charges the ultracapacitor.Experimental results under HWFET show that the proposed fully active dual-energy source hybrid energy storage system and the energy management strategy based on fuzzy logic can effectively protect lithium-ion power battery from large current fluctuations,thereby extending lithium-ion power battery life.