Patent Number: 7,825,620

Title: Controller and constant measuring apparatus for AC motor

Abstract: A controller and a constant measuring apparatus have a means for supplying a synthesized current, resulting from superimposing an AC current to a DC current, from an inverter and for changing the DC current component of the synthesized current continuously or discontinuously. Accordingly, the controller and constant measuring apparatus can measure inductances, which are electric constants of the AC motor, with high accuracy and can use the measured inductances for control.

Inventors: Nakatsugawa; Junnosuke (Hitachi, JP), Iwaji; Yoshitaka (Hitachinaka, JP), Tobari; Kazuaki (Hitachiota, JP)

Assignee: Hitachi, Ltd.

International Classification: H02P 27/04 (20060101)

Expiration Date: 2019-11-02 0:00:00