Abstract
This paper proposes a new drive system for a large EV that achieves low cost, large power, and low power consumption by the combination of conventional motors and a simple gearbox. This system is structured to run with one motor in the low-speed range and two motors in the high-speed range, and can switch between the two modes smoothly. Bench tests confirmed that this structure expanded the high-efficiency area of the system. In addition, motor drive systems often have issues with the motor and inverter when the vehicle is stopped on an uphill gradient by accelerator operation only. Hill-stop bench tests confirmed the advantage of the lowest-speed mode of this system. Results found that the thermal load of the inverter is reduced in the lowest-speed mode compared to the one-motor mode, which is equivalent to a single-motor system.
