Detecting hidden faults in reliable power systems

• US 6,157,308 A
• Filed: 06/10/1999
• Issued: 12/05/2000
• Est. Priority Date: 06/10/1999
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Byers, Charles Calvin
• Primary Examiner(s): Lieu, Julie
• Application Number:
  US09/329,687
• Time in Patent Office: 544 Days
• Field of Search: 340/635, 340/645, 340/650, 340/651, 340/652, 340/660, 340/661, 324/512, 324/522, 324/523
• US Class Current: 340/635
• CPC Class Codes: G01R 31/2632 for testing diodes
• CPC Class Codes: G01R 31/40 Testing power supplies testing photovoltaic devices H02S50/10

Abstract

A method and apparatus for detecting silent faults in feeding diodes of redundant DC power supplies. The voltages on both sides of the feeding diodes are measured. Arrangements are then made to ensure that if corresponding feeding diodes are both operative, that current flows through a particular one of these diodes. The measurements of voltage under the various conditions will reveal any open or shorted feeding diodes. The voltage across a diode can be altered by heating the diode through the process of heating a power resistor that is in thermal contact with that diode. Alternatively, a controllable rectifier of a power source can be controlled to reduce the voltage of that power source, and thereby drive current through the diode connected to the other power source. Advantageously, this arrangement allows silent faults in these diodes to be detected without substantial risk of causing the failure in the powered system.

Claims

1. Apparatus for providing a reliable power supply, comprising:

a pair of DC power sources and diodes connecting each of said power sources to a power converter;

characterized in that said system further comprises access means and processor means for measuring the voltage on both sides of each of said diodes;

wherein the measured voltages are analyzed by said processor means in order to detect open or shorted diodes;

further comprising;

a plurality of power resistors, each in close proximity and in thermal contact with one of said diodes; and

means for applying power selectively to each of said power resistors;

wherein said processor means further analyzes the changes in voltage across said diodes when power is applied to a power resistor in close proximity to one of said plurality of diodes;

wherein the voltage measurements across said diodes further reveal information about incipient or actual diode failures.

2. The apparatus of claim 1, further comprising power good and power alarm outputs whose states are determined by the results of the diode voltage drop measurements.