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:
Jan. 09, 2024
Filed:
Jun. 13, 2018
Hitachi Industrial Equipment Systems Co., Ltd., Tokyo, JP;
Hiroshi Watanabe, Tokyo, JP;
Masataka Sasaki, Tokyo, JP;
Masahiro Hiraga, Tokyo, JP;
Yusuke Arao, Tokyo, JP;
Atsuhiko Nakamura, Tokyo, JP;
Hiroyuki Tomita, Tokyo, JP;
Kazushige Hotta, Tokyo, JP;
Yusaku Onuma, Tokyo, JP;
Hitachi Industrial Equipment Systems Co., Ltd., Tokyo, JP;
Abstract
The purpose of the present invention is to provide a speed detection method for maintaining a fine time axis resolution and a power conversion device that uses the method. This power conversion device comprises an inverter for converting DC voltage into AC voltage and supplying the same to a motor, a motor speed calculation unit for calculating the speed of the motor from output pulses obtained from an encoder connected to the motor, and a control unit for receiving the motor speed from the motor speed calculation unit and controlling the inverter. In the power conversion device, the motor speed calculation unit measures the duty cycle of the output pulses, calculates the speed using the half cycles of the output pulses if the duty cycle is within a prescribed range from 50%, and calculates the speed using the full cycles of the output pulses if the duty ratio is outside of the prescribed range from 50%.