US 6,724,643 B1Granted

Control system and method employing active temperature balance for controlling rectifier bridge

AssigneeEaton Corporation

InventorIrving A. Gibbs

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Abstract

A method for controlling a parallel array of rectifier bridges includes outputting control signals to repetitively fire bridge elements; skipping repetitive firing of the elements for one out of plural counts; sensing temperatures of the elements; averaging some of the sensed temperatures to provide a corresponding average temperature for each of the parallel bridge elements; comparing one of the sensed temperatures to the corresponding average temperature; increasing the counts when the sensed temperature of one of the elements is less than the corresponding average temperature, or decreasing the counts when the sensed temperature of the one of the elements is greater than the corresponding average temperature; and setting the counts to a first predetermined value when the sensed temperature of the one of the elements is greater than a second predetermined value above the corresponding average temperature.

Claims26

Dependent claims

A control system comprising:

a firing control circuit outputting a plurality of firing commands;
a parallel array of a plurality of rectifier bridges, each of said rectifier bridges converting a plurality of alternating current voltages from a plurality of alternating current phases to a voltage, each of said rectifier bridges comprising a plurality of segments, each of said segments having an element, each of the elements of one of said rectifier bridges having a temperature and being electrically interconnected in parallel with at least a corresponding one of the elements of the other of said rectifier bridges;
a plurality of temperature sensors, each of said temperature sensors sensing the temperature of a corresponding one of said elements;
a plurality of bridge control circuits, each of said bridge control circuits inputting one of the firing commands, outputting a plurality of control signals responsive to said one of the firing commands to repetitively fire at least some of said elements of a corresponding one of said rectifier bridges, and inputting the sensed temperatures of said elements of the corresponding one of said rectifier bridges;
a communication channel communicating the input sensed temperatures from the bridge control circuits to the firing control circuit, and communicating the firing commands from the firing control circuit to the bridge control circuits;
and
an output having said voltage,
wherein said firing control circuit includes means for averaging some of the input sensed temperatures to provide a corresponding average temperature for each of the parallel elements of said rectifier bridges, for comparing one of the input sensed temperatures to the corresponding average temperature, for skipping repetitive firing of at least one of said elements for one out of a plurality of counts, for increasing said counts when the input sensed temperature of one of said at least one of said elements is less than the corresponding average temperature or for decreasing said counts when the input sensed temperature of said one of said at least one of said elements is greater than the corresponding average temperature, and for setting said counts to a first predetermined value when the input sensed temperature of said one of said at least one of said elements is greater than a second predetermined value above said corresponding average temperature.

5 more elements

A method for controlling a parallel array of a plurality of rectifier bridges, each of said rectifier bridges converting a plurality of alternating current voltages from a plurality of alternating current phases to a voltage, each of said rectifier bridges comprising a plurality of segments, each of said segments having an element, each of the elements of one of said rectifier bridges having a temperature, being electrically interconnected in parallel with at least a corresponding one of the elements of the other of said rectifier bridges, and being responsive to a control signal, said method comprising:

outputting the control signals to repetitively fire said elements;
skipping repetitive firing of at least one of said elements for one out of a plurality of counts;
sensing the temperatures of said elements;
averaging some of the sensed temperatures to provide a corresponding average temperature for each of the parallel elements of said rectifier bridges;
comparing one of the sensed temperatures to the corresponding average temperature;
increasing said counts when the sensed temperature of one of said at least one of said elements is less than the corresponding average temperature, or decreasing said counts when the sensed temperature of said one of said at least one of said elements is greater than the corresponding average temperature;
and
setting said counts to a first predetermined value when the sensed temperature of said one of said at least one of said elements is greater than a second predetermined value;
above the corresponding average temperature.

6 more elements

Dependencies are inferred from the claim text.