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:
Nov. 24, 2009
Filed:
Apr. 19, 2007
Yoichi Morishima, Houston, TX (US);
Takashi Morishita, Houston, TX (US);
Yoichi Morishima, Houston, TX (US);
Takashi Morishita, Houston, TX (US);
Toshiba International Corporation, Houston, TX (US);
Abstract
An uninterruptible power supply having a controllable leakage current is disclosed. The leakage current is controlled by adjusting a switching speed (i.e., dV/dt rate) of switches in the output inverter (i.e. DC-AC converter stage). Leakage current can be reduced by reducing the switching speed (dV/dt rate) of the output inverter switches. In one embodiment, leakage current is held constant or moderated as output power decreases by reducing the switching speed (responsive to leakage current) as output power decreases. The switching speed can be adjusted by adjusting the gate resistance or gate voltage. Increasing the gate resistance or decreasing the gate voltage will cause a reduction in the switching speed, and increase in leakage current. Conversely, reducing the gate resistance, or decreasing the gate voltage will cause an increase in switching speed, and increase in leakage current. The present invention is applicable to any uninterruptible power supply having output inverter switches.