Motor control device and electric power steering device

Abstract

A motor control device includes control calculation means formed by an open loop control unit and a dq-axis / 3-phase conversion unit. The open loop control unit obtains voltage instruction values vd, vq on the d-axis and q-axis according to current instruction values id*, iq* on the d-axis and q-axis, the armature winding interlinking magnetic flux quantity f, and the rotor angular velocity omega e in the motor. The dq-axis / 3-phase conversion unit converts the voltage instruction values vd, vq into phase voltage instruction values Vu, Vv, Vw. On the other hand, a data acquisition unit acquires angle-dependency data indicating dependency on the electric angle indicated by a secondary higher harmonic component concerning the electric angle of the d-axis or the q-axis component of the motor current according to the current detection value ia and the electric angle theta. A correction coefficient decision unit decides a correction coefficient for correcting the phase voltage instruction value so as to reduce the dependency according to the angle-dependency data. A correction execution unit corrects the phase voltage instruction values Vu, Vv, Vw obtained by the dq-axis / 3-phase conversion unit, according to the decided correction coefficient.

Description

technical field [0001] The present invention relates to a motor control device for driving a brushless motor and an electric power steering device having such a motor control device. Background technique [0002] Conventionally, an electric power steering apparatus is used in which an electric motor is driven in accordance with a steering torque applied by a driver to a handle (steering wheel) to impart steering assist force to a steering mechanism of a vehicle. Conventionally, brushed motors have been widely used as electric motors for electric power steering devices, but in recent years, brushless motors have also been used from the viewpoint of improvement in reliability and durability, reduction in inertia, and the like. [0003] In general, a motor control device detects a current flowing through the motor in order to control torque generated in the motor, and performs PI control (proportional-integral control) based on the difference between the current to be supplied ...

AI Technical Summary

Problems solved by technology

[0015] However, if the wiring pattern is formed so as to sufficiently reduce the torque ripple, the circuit pattern in the above-mentioned motor drive circuit board becomes complicated, and the space for forming the circuit pattern increases.

That is, in the motor drive circuit board, although the wiring pattern can be designed so that the wiring resistance of the path from the power supply terminal to the ground terminal is consistent between phases, it is difficult to achieve a sufficient reduction in the wiring resistance so that it does not affect the motor drive. degree, the switching elements constituting the motor drive circuit are arranged symmetrically

Therefore, if the resistance component from the power supply terminal to the output terminal of the motor drive circuit (hereinafter referred to as "upper arm resistance") and the resistance component from the output terminal to the ground terminal (hereinafter referred to as "lower arm resistance") are identical, When the wiring pattern is formed in this way, the circuit pattern becomes complicated, and a large space is required for forming the circuit pattern, and the size of the substrate increases.

As a result, in the electric power steering device, the area occupied by the board in the ECU becomes large, which violates the above-mentioned request for miniaturization, etc.

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