CONTROL METHOD OF MOTOR FOR MOTOR VEHICLE

摘要

PURPOSE:To provide a controller for induction motor wherein the induction motor is protected against breakdown due to overrotation. CONSTITUTION:An induction motor 3 is driven through an inverter 2 which is fed with DC power from a battery 1. A driving circuit 8 drives the inverter 2. A slip frequency calculating circuit 4 sets a target torque to be produced from the motor 3 based on an acceleration signal and a brake signal while a sensor 5 detects actual rotational speed of the motor 3 and a slip frequency is determined based on the actual rotational speed and the target torque. A current command value calculating circuit 6 determines a primary current command value of the motor 3 based on the slip frequency fed from the slip frequency calculating circuit 4 and then controls the driving circuit 8 such that the command current will be equal to an actual primary current of the motor 3 detected through current detecting sensors 7a, 7b. When the actual rotational speed exceeds a preset rotational speed, slip frequency determined through the slip frequency calculating circuit 4 is modified to a value being set such that appropriate torque is produced in reverse direction from the induction motor.