Overcurrent suppression scheme for DC bus current at sudden load change of interior permanent magnet synchronous motor

Electric vehicle (EV) runs on various surface condition roads. When the road surface condition is changing instantaneously, ex. a vehicle is running from a normal condition road to an icy surface such as an icy maintenance hatch or snow-covered road, output torque of a traction motor has to be controlled according to the road surface condition. Under the condition, if a slip of a driving wheel arises, there are possibilities that the large current ripple breaks the components, especially switching device, or rising rate of velocity of the vehicle suddenly increase just after recovery of a load. As a solution of these problems, a novel control scheme was proposed, and the effectiveness of the control scheme was verified through experiments of a drive system for EV.