METHOD AND APPARATUS FOR PRE-CHARGING POWER CONVERTERS AND DIAGNOSING PRE-CHARGE FAULTS
First Claim
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1. A power converter, comprising:
- an input to receive AC electrical input power;
an output to provide DC electrical output power;
a rectifier operatively coupled with the input and the output and operative to convert the input power to provide DC electrical power at the output;
a pre-charge circuit, comprising;
a resistor coupled between the rectifier and the output, anda switching device coupled between the rectifier and the output and being operable in a first mode to allow current to flow from the rectifier to the output through the resistor and in a second mode to bypass the resistor;
a feedback system operative to measure a DC voltage associated with the output and to provide a feedback signal indicative of the measured DC voltage; and
a controller receiving the feedback signal from the feedback system and providing a pre-charge control signal to the switching device to selectively operate the pre-charge circuit in a pre-charge mode with the switching device operated in a first mode during startup of the converter; and
a pre-charge diagnosis system operatively coupled with the controller to selectively detect at least one converter fault based at least partially on the feedback signal during startup and to selectively discontinue application of power to the input and place the converter in a fault state based on detected faults.
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Abstract
Power conversion systems and diagnostic techniques are presented for detecting suspected converter faults when a pre-charge circuit is engaged during system startup, in which known or estimated system characteristics are used to derive expected converter voltage values or rate of change values and the levels are measured during startup to ascertain whether the pre-charge circuit or other converter components are faulted.
62 Citations
19 Claims
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1. A power converter, comprising:
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an input to receive AC electrical input power; an output to provide DC electrical output power; a rectifier operatively coupled with the input and the output and operative to convert the input power to provide DC electrical power at the output; a pre-charge circuit, comprising; a resistor coupled between the rectifier and the output, and a switching device coupled between the rectifier and the output and being operable in a first mode to allow current to flow from the rectifier to the output through the resistor and in a second mode to bypass the resistor; a feedback system operative to measure a DC voltage associated with the output and to provide a feedback signal indicative of the measured DC voltage; and a controller receiving the feedback signal from the feedback system and providing a pre-charge control signal to the switching device to selectively operate the pre-charge circuit in a pre-charge mode with the switching device operated in a first mode during startup of the converter; and a pre-charge diagnosis system operatively coupled with the controller to selectively detect at least one converter fault based at least partially on the feedback signal during startup and to selectively discontinue application of power to the input and place the converter in a fault state based on detected faults. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for detecting power converter faults during startup, the method comprising:
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activating a pre-charge circuit connected to an output of a rectifier; measuring an initial converter DC voltage; determining an expected range of DC voltages or DC voltage change rates based at least partially on the initial converter DC voltage; applying AC electrical input power to the rectifier; again measuring the converter DC voltage after application of the input power during startup of the converter; and determining whether a fault is suspected in the converter during startup based at least partially on the measured DC voltage. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A computer readable medium having computer executable instructions for performing the steps of:
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activating a pre-charge circuit connected to an output of a rectifier; measuring an initial converter DC voltage; determining an expected range of DC voltages or DC voltage change rates based at least partially on the initial converter DC voltage; applying AC electrical input power to the rectifier; again measuring the converter DC voltage after application of the input power during startup of the converter; and determining whether a fault is suspected in the converter during startup based at least partially on the measured DC voltage.
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Specification