Motor control device and electric power steering device

Abstract

An open loop control unit obtains voltage instruction values v d and v q on dq-axes based on current instruction values i d * and i q * on the dq-axes, an armature winding interlinking magnetic flux number ¦, and the angular velocity É e of a rotor in a motor, and a dq-axis / 3-phase conversion unit converts the voltage instruction values v d , and v q into phase voltage instruction values V u , V v , and V w . On the other hand, a data acquisition unit acquires angle-dependent data showing the dependency of a secondary harmonic component concerning the electric angle of the d-axis or q-axis component of the motor current on the electric angle, based on the current detection value i a and the electric angle ¸, and a correction coefficient determination unit determines correction coefficients for correcting the phase voltage instruction values so as to reduce the dependency based on the angle-dependent data. A correction execution unit corrects the phase voltage instruction values V u , V v , and V w obtained by the dq-axis / 3-phase conversion unit, based on the determined correction coefficients.

Description

[0001] This application is a divisional application of the PCT application with the application number 200980102108.9, the date of entering the Chinese national phase is July 13, 2010, and the title of the invention is "motor control device and electric power steering device". technical field [0002] 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 [0003] Conventionally, an electric power steering apparatus is used that drives an electric motor in response to 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, ...

AI Technical Summary

Problems solved by technology

[0016] 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") is the same as the resistance component from the output terminal to the ground terminal (hereinafter referred to as "lower arm resistance") 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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