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:
May. 25, 1993
Filed:
Dec. 16, 1991
Eiichi Sugishima, Aichi, JP;
Taro Ando, Aichi, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus and method for detecting a ground fault occurring on an output side of an inverter circuit, which includes a converter circuit for rectifying an alternating current into a direct current, a capacitor for smoothing the direct current, an inverter circuit for converting the smoothed direct current into a predetermined frequency and voltage through the on/off operation of switching elements connected in parallel with diodes, and a PWM signal generator for controlling the on/off of the switching elements. The ground fault detector includes current detectors for detecting current flowing in the switching elements, a device for detecting an overcurrent flowing from one of the switching elements and for outputting an overcurrent signal when the output of any of the current detectors exceeds a predetermined value, a device for detecting a zero vector signal transmitted by the PWM signal generator, and a ground fault detector circuit for detecting a ground fault condition in accordance with the overcurrent signal and the zero vector detection signal.