Distributed diode fault check
First Claim
1. A fault test method for use in a system comprising one or more system units, wherein each system unit comprises at least two isolation devices and is powered by a plurality of redundant power supplies, each isolation device requires a forward biasing voltage at least equal to a respective forward bias voltage value to be operable in a normal conductive state and is electrically connected with a respective one of said power supplies such that each power supply has associated with it a set of one or more isolation devices, and an output of each isolation device is connected to a common load of the corresponding system unit, the method being performed by a testing system and comprising:
- selecting as a subject for a test procedure, the set of isolation devices associated with a corresponding one of said power supplies;
controlling the power supplies during the test procedure to marginally vary an output voltage of at least one power supply such that a differential voltage is applied between an output of the power supply associated with the selected set of isolation devices and outputs of the remaining power supplies for selectively changing the conductive state of at least one isolation device by reducing the forward voltage thereof to less than said respective forward bias voltage;
measuring the current through each isolation device in said selected set of isolation devices; and
determining whether each measured current is consistent with the existence of a fault condition in the respective isolation device.
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Accused Products
Abstract
A method and apparatus for testing for latent faults in the isolation devices of a system including redundant power supplies which supply power to one or more system units. A system controller is operable to perform a test cycle to perform the fault checks, which may including checks for short circuits and/or open circuits. The checks may be performed within a test cycle in which each of the isolation devices in the system is tested. The test cycle may be performed at regular intervals, the interval between each cycle being determinable by user input. In the event that a fault in one of the isolation devices is detected, the system controller may be operable to report the fault to an alarm system.
19 Citations
31 Claims
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1. A fault test method for use in a system comprising one or more system units, wherein each system unit comprises at least two isolation devices and is powered by a plurality of redundant power supplies, each isolation device requires a forward biasing voltage at least equal to a respective forward bias voltage value to be operable in a normal conductive state and is electrically connected with a respective one of said power supplies such that each power supply has associated with it a set of one or more isolation devices, and an output of each isolation device is connected to a common load of the corresponding system unit, the method being performed by a testing system and comprising:
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selecting as a subject for a test procedure, the set of isolation devices associated with a corresponding one of said power supplies;
controlling the power supplies during the test procedure to marginally vary an output voltage of at least one power supply such that a differential voltage is applied between an output of the power supply associated with the selected set of isolation devices and outputs of the remaining power supplies for selectively changing the conductive state of at least one isolation device by reducing the forward voltage thereof to less than said respective forward bias voltage;
measuring the current through each isolation device in said selected set of isolation devices; and
determining whether each measured current is consistent with the existence of a fault condition in the respective isolation device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A carrier medium carrying processor implementable instructions for instructing a processor of a testing system to perform a fault test method for use in a system comprising one or more system units, wherein each system unit comprises at least two isolation devices and is powered by a plurality of redundant power supplies, each isolation device requires a forward biasing voltage at least equal to a respective forward bias voltage value to be operable in a normal conductive state and is electrically connected with a respective one of said power supplies such that each power supply has associated with it a set of one or more isolation devices, and an output of each isolation device is connected to a common load of the corresponding system unit, the method comprising:
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selecting as a subject for a test procedure, the set of isolation devices associated with a corresponding one of said power supplies;
controlling the power supplies during the test procedure to marginally vary an output voltage of at least one power supply such that a differential voltage is applied between an output of the power supply associated with the selected set of isolation devices and outputs of the remaining power supplies for selectively changing the conductive state of at least one isolation device by reducing the forward voltage thereof to less than said respective forward bias voltage;
measuring the current through each isolation device in said selected set of isolation devices; and
determining whether each measured current is consistent with the existence of a fault condition in the respective isolation device.
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19. A system comprising:
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one or more system units, each system unit comprising at least two isolation devices, and measuring circuitry for measuring the current through isolation devices, each isolation device requiring a forward biasing voltage at least equal to a respective forward bias voltage value to be operable in a normal conductive state and having an output connected to a common load of the respective system unit;
a plurality of redundant power supplies, each supplying power for at least one system unit via an isolation device of the respective system unit such that each power supply has associated with it a set of one or more isolation devices, each power supply comprising control circuitry operable to control an output voltage of that power supply; and
a system controller, operable; to select as a subject for a test procedure, the set of isolation devices being associated with a corresponding one of said power supplies;
to cause at least one power supply to marginally vary an output voltage thereof such that a differential voltage is applied between an output of the power supply associated with a selected set of isolation devices and outputs of the remaining power supplies for selectively changing the conductive state of at least one isolation device by reducing the forward voltage thereof to less than said respective forward bias voltage, andto determine whether the current measured by said measuring circuitry through each isolation device in said selected set of isolation devices is consistent with the existence of a fault condition in the respective isolation device. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification