锂离子电池放电起动瞬间电压陡降以及放电停止后电压回升使开路电压和实时电压关系难以确定,进而导致常规方法无法准确估算荷电状态(State of Charge,SOC)。从能量角度提出一种应用于电池放电过程中估算SOC的新方法。首先构造带有非线...锂离子电池放电起动瞬间电压陡降以及放电停止后电压回升使开路电压和实时电压关系难以确定,进而导致常规方法无法准确估算荷电状态(State of Charge,SOC)。从能量角度提出一种应用于电池放电过程中估算SOC的新方法。首先构造带有非线性受控源的双电源模型,然后根据电池电量特性进行模型参数辨识。通过对锂离子电池进行恒流、变流和模拟工况放电过程中的SOC预测,对比模型预测和实测SOC可看出,该方法能够准确模拟电池电量特性,精准估算电池SOC。展开更多
Based on the extended application of COMSOL multiphysics, a novel dual heat source model for pulsed laser-gas tungsten arc （GTA） hybrid welding was established. This model successfully solved the problem of simulati...Based on the extended application of COMSOL multiphysics, a novel dual heat source model for pulsed laser-gas tungsten arc （GTA） hybrid welding was established. This model successfully solved the problem of simulation inaccuracy caused by energy superposition effect between laser and arc due to their different physical characteristics. Numerical simulation for pulsed laser-GTA hybrid welding of magnesium alloy process was conducted, and the simulation indicated good agree- ments with the measured thermal cycle curve and the shape of weld beads. Effects of pulse laser parameters （laser-excited current, pulse duration, and pulse frequency） on the temperature field and weld pool morphology were investigated. The experimental and simulation results suggest that when the laser pulse energy keeps constant, welding efficiency of the hybrid heat source is increased by increasing laser current or decreasing pulse duration due to the increased ratio of the weld bead depth to width. With large laser currents, severe spatters tend to occur. For optimized welding process, the laser current should be controlled in the range of 150-175 A, the pulse duration should be longer than 1 ms, and the pulse frequency should be equal to or slightly greater than 20 Hz.展开更多
文摘锂离子电池放电起动瞬间电压陡降以及放电停止后电压回升使开路电压和实时电压关系难以确定,进而导致常规方法无法准确估算荷电状态(State of Charge,SOC)。从能量角度提出一种应用于电池放电过程中估算SOC的新方法。首先构造带有非线性受控源的双电源模型,然后根据电池电量特性进行模型参数辨识。通过对锂离子电池进行恒流、变流和模拟工况放电过程中的SOC预测,对比模型预测和实测SOC可看出,该方法能够准确模拟电池电量特性,精准估算电池SOC。
基金This work was supported by the Natural Science Foundation of Liaoning Province of China （Grant Nos. 201602391 and 20170540460）.
文摘Based on the extended application of COMSOL multiphysics, a novel dual heat source model for pulsed laser-gas tungsten arc （GTA） hybrid welding was established. This model successfully solved the problem of simulation inaccuracy caused by energy superposition effect between laser and arc due to their different physical characteristics. Numerical simulation for pulsed laser-GTA hybrid welding of magnesium alloy process was conducted, and the simulation indicated good agree- ments with the measured thermal cycle curve and the shape of weld beads. Effects of pulse laser parameters （laser-excited current, pulse duration, and pulse frequency） on the temperature field and weld pool morphology were investigated. The experimental and simulation results suggest that when the laser pulse energy keeps constant, welding efficiency of the hybrid heat source is increased by increasing laser current or decreasing pulse duration due to the increased ratio of the weld bead depth to width. With large laser currents, severe spatters tend to occur. For optimized welding process, the laser current should be controlled in the range of 150-175 A, the pulse duration should be longer than 1 ms, and the pulse frequency should be equal to or slightly greater than 20 Hz.
