| 摘要 |
PURPOSE:To reduce an adverse effect on a battery by a rush current of the battery at the time of an over discharge and to prolong an operating time of an electric car by limiting the amount of change of a chopper conduction ratio in accordance with a residual capacity detected by a residual capacity detecting means for the battery. CONSTITUTION:When a forward-backward switch FR is turned ON, the residual capacity of a battery at this time point calculated by a residual capacity computing processing 30 is read in a microcomputer 17. When the residual capacity is judged to be a prescribed amount or above, the amount of change of a chopper conduction ratio is set at an ordinary value by a motor control processing 29 for running. When the residual capacity is judged to be the prescribed amount or below, on the other hand, the amount of change of the chopper conduction ratio is set to be smaller than the ordinary value. Accordingly, a sudden fluctuation of the torque of a motor is limited at the time, for instance, when an electric car loaded with goods or the like is to be made to depart when the battery is in the state of an over discharge. Thereby a sharp voltage fall of the battery can be prevented. |
