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:
Mar. 27, 2001
Filed:
Feb. 04, 1999
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
Current sense voltages (V,˜V,), which are the detected values of n (≧2) IGBTs connected in parallel, are converted into digital form, and thereafter, are subjected to an operation processing. After the current sense voltages (V,˜V,) are converted into collector currents (I,˜I,) by use of constants (G,˜G,and V,˜V,)(step 103), current deviations (&Dgr;I,˜&Dgr;I,) respectively defined as differences of the collector currents (I,˜I,) from the average (I,) thereof are calculated (step 104, 105). Drive control voltages (V,˜V,) are renewed by changes (&Dgr;V,˜&Dgr;V,) which are respectively obtained by multiplying the current deviations (&Dgr;I,˜&Dgr;I,) by factors (K,)(step 106, 107). The drive control voltage (V,˜V,) are converted into analogue form, and thereafter, supplied to n IGBTs as their gate voltages (V,). The constants (G,˜G,, V,˜V,, and K,) are prepared individually for respective n switching elements. As a result, current imbalance of plural switching elements connected in parallel is eliminated in high precision.