The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 08, 1997
Filed:
Aug. 18, 1995
Yoshiaki Doyama, Hirakata, JP;
Keizo Matsui, Kobe, JP;
Yoshiteru Ito, Ibaraki, JP;
Kaneharu Yoshioka, Katano, JP;
Hideo Ogata, Yao, JP;
Izumi Yoshida, Nara-ken, JP;
Shusaku Watakabe, Nara, JP;
Matsushita Electric Industrial Co.,Ltd., Osaka-fu, JP;
Matsushita Refrigeration Company, Osaka-fu, JP;
Abstract
An inverter control apparatus for controlling a command frequency and a command voltage which are supplied to an inverter which then supplies AC power of a desired frequency, accordingly, to an induction motor. The inverter control apparatus receives a requested rotational speed of the motor and an actual rotational speed of the motor is obtained by detecting a frequency of a fluctuation component of a drive current supplied from the inverter to the induction motor. The difference between the requested rotational speed and the actual rotational speed represents a slip amount, which is added to the requested rotational speed to produce a command frequency. The command voltage is set to a voltage acquired when the monitored drive current is at a minimum value. Thus, the inverter control apparatus is able to maintain power consumption at the lowest possible level in response to changes in the operating environment without requiring a motor constant input or a motor speed detector, while compensating the slip ratio of the induction motor to maintain the motor speed at a target level.