纯电动汽车低压电气系统效率研究

In order to reduce the energy consumption and extend the driving range of battery electric vehicles, the cause of the poor efficiency of low-voltage electric system is systematically investigated for improving its energy management strategy. Firstly, the efficiency model of the low-voltage system, adapted to longtime fast operation is built by using forward simulation method, in which, the efficiency model of DC/DC converter consists of a first-order inertia loop and an efficiency-interpolation function, while the system control model covers two strategies for floating control and rule control. Then, test bench is constructed to measure the performances of the components and system with model parameters extracted. Finally, both simulation and test are conducted to study the influences of load power, converter efficiency, ambient temperature, battery types, and control strategies on system efficiency. The results show that the system efficiency will fall with the reduction of mean power, the reduction of converter efficiency and the increase of battery inner resistance, and will rise with the shortening of idle period, the improvement of control strategies and the change of battery types, and in light load condition, using rule control can enhance the efficiency of low-voltage electric system by 10%.