Motor energization control method

Abstract

The invention provides a motor energization control method capable of continuing to drive a motor to cross a dead point even if a phase failure occurs. When a phase failure has occurred, if the electrical angle is located at a predetermined angle earlier than a torque dead point at which the output torque is zero, and if the rotational speed and steering torque of the electric motor (15) satisfy predetermined conditions, the electrical angle is returned, a phase current is passed in the opposite direction until the first electrical angle ([theta] 4) is reached, and the electric motor (15) is rotated in the opposite direction. Then, a phase current is passed in the forward direction, the electric motor (15) is rotated forward until a second electrical angle (theta5) is reached, and controlis performed so as to straddle the torque dead center by maintaining a sufficient angular velocity.

Description

technical field [0001] The present invention relates to a motor energization control method used, for example, in an electric power steering device or the like. Background technique [0002] In recent years, in electric power steering devices, there has been an increasing demand for continuing to drive (assist) the electric motor through the remaining two normal phases without stopping the motor control when an abnormality occurs in one phase of the three-phase electric motor. . In such a phase failure, around the electrical angle corresponding to the failure, the motor torque decreases, creating a region where the steering wheel cannot be turned. Therefore, until now, it has been a problem to improve the steering feeling by going over the motor torque reduction region at the time of a phase failure. [0003] For example, Patent Document 1 discloses an electric power steering device that, when driven by a two-phase motor, when the sum of the steering torque and the steerin...

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Problems solved by technology

[0006] As another technique, there has been proposed a configuration in which the electric current command value is increased and corrected to accelerate the rotation of the motor when the electrical angle is in the acceleration range, thereby overriding the range where the motor torque decreases. However, when the vehicle speed is low such as when the vehicle is stopped , there is the problem that it is difficult to cross the region of reduced motor torque by simply accelerating

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