Multimode Shift Control Strategy Without Power Interruption of Dual-Motor 4WD Electric Vehicle With Two-Speed Transmission

The two-speed transmission can effectively improve the power and economy of electric vehicles but can also bring the problem of power interruption. Therefore, it is important to adopt the gear-shift control without power interruption, which can ensure the drivability and acceleration performance of the vehicle. At present, a variety of shift modes without power interruption have been proposed. Among them, the traditional multiroute power compensation shift mode has the problems of large energy loss, while the multisource power compensation mode control mode cannot guarantee the vehicle acceleration performance under the condition of high torque demand. Therefore, a multimode shift control strategy is proposed for dual-motor four-wheel drive (4WD) electric vehicles with a two-speed transmission. First, different shift modes are analyzed and compared, so as to clarify their respective applicable driving conditions. Next, a Transition Mode is further proposed, and then, based on the traditional shift lines, the shift area maps are drawn and divided innovatively to clarify the working interval of different shift modes. Simulation results show that the control strategy can effectively avoid the energy slip loss in the process of shifting and can give priority to the acceleration performance in conditions of high torque demand.