Patent ID: 6647325
Filing Date: 2003-11-11
Classification: B60L,Y02T

Abstract:
A control system for an electric motor for driving an electric vehicle while an output of said electric motor is controlled on an accelerator opening degree corresponding to a displacement quantity of an accelerator operation member, said control system comprising an acceleration sensor to output an acceleration signal having a magnitude corresponding to said accelerator opening degree by detecting said accelerator opening degree; rotational speed detection means to detect a rotational speed of said electric motor; steady-state-time drive current control means to control a drive current of said electric motor in accordance with said acceleration signal; lock state judgment means to judge that said electric motor is in the lock state when the state where said rotational speed detected by said rotational speed detection means is equal to or less than a set lock start rotational speed while said accelerator opening degree detected from said acceleration signal is equal to or more than a set lock judgment opening degree continues during a set lock start judgment time and to judge that said lock state is released when the state where said accelerator opening degree is less than said lock judgment opening degree or the state where said rotational speed is equal to or more than a lock release rotational speed set at a value higher than said lock start rotational speed continues for a set lock release judgment time; and lock-time drive current control means to perform a drive current limit control in which said drive current is reduced from a value determined by said steady-state-time drive current control means to a lock-time limit value so as to limit the maximum value of said drive current to a value equal to or less than the lock-time limit value when it is judged by said lock state judgment means that the electric motor is in the lock state and to release said drive current limit control whereby said drive current is increased from said value equal to or less than said lock-time limit value to said value determined by said steady-state-time drive current control means when it is judged that said lock state is released.