STACK DETECTOR OF ELECTRIC MOTOR TYPE FOUR-WHEEL DRIVE VEHICLE AND MOTOR DRIVE CONTROLLER AT THE TIME OF STACKING

摘要

PROBLEM TO BE SOLVED: To provide a stack detector which can detect escape from stack state even in case of extremely low speed, and to provide a motor torque controller at the time of stacking arranged such that the motor torque does not exceed an allowable upper limit motor torque determined by the allowable maximum torque of an electric motor and a reduction gear provided between the driving wheels of the electric motor depending on the detection results.

SOLUTION: A decision is made at S21 that the drive slip ΔVf of an engine drive wheel (front wheel) is 3 km/h or above (occurrent of drive slip), a decision is made at S22 that the r. p. m. Nm of a motor is lower than a stack judgment r. p. m. (stack state), a decision is made at S23 that the stack state sustains over a set time Δt or longer, and escape from stack state is tried at S24 by performing the following motor drive control at the time of stacking. At S24, motor torque Tm is searched from the conduction amount of a motor, field voltage of the motor and the motor temperature based on a predetermined map, and the motor torque is feedback controlled such that a motor torque estimation value Tm increases while following up a motor torque command value having a time series variation determined not to exceed an allowable upper limit value of motor torque corresponding to the allowable maximum torque of a reduction gear provided between the motor and the motor drive wheel (rear wheel).

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