Kabushiki Kaisha Yaskawa Denki

Noriaki Sueyoshi

Ryuichi Oguro

Masanobu Inazumi

Masanori Kawatani

In sensorless vector control performed through use of a rotation speed of a synchronous motor 6 and the position of a rotor, a positive current is caused to flow to a &#x3b3; axis on the assumption that a 'd' axis serving as a true magnetic axis is out of phase with the &#x3b3; axis by only an angle of load &#x3b8;e, whereby torque which is proportional to i&#x3b3; sin &#x3b8;e and directed toward the &#x3b3; axis arises in the magnetic axis. Accordingly, a deviation between a d-q axis serving as a true magnetic axis and a &#x3b3;-&#x3b4; axis serving as a control axis is eliminated. Even if load is exerted on the motor, the &#x3b3; axis serving as a control axis is constantly aligned with the 'd' axis serving as the magnetic axis of the synchronous motor, thereby enabling excellent vector control.

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Fukuoka, Japan

Noriaki Sueyoshi