Motor disconnect arrangement for a variable speed drive
First Claim
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1. A drive system for a plurality of motors comprising:
- a variable speed drive, the variable speed drive comprising;
a converter stage to convert an input AC voltage to a DC voltage, the converter stage being configured to be electrically connectable to an AC power source;
a DC link stage to filter and store energy from the converter stage, the DC link stage being electrically connected to the converter stage;
an inverter stage comprising a plurality of inverters electrically connected in parallel to the DC link stage, each inverter of the plurality of inverters being configured to convert a DC voltage to an output AC voltage to power a corresponding motor of a plurality of motors, and each inverter of the plurality of inverters being configured to operate substantially independently of other inverters of the plurality of inverters; and
wherein the converter stage is configured to provide a boosted DC voltage to the DC link stage and each inverter of the plurality of inverters is configured to provide an output AC voltage greater than the input AC voltage; and
a plurality of connecting mechanisms, each connecting mechanism of the plurality of connecting mechanisms being connected in series between an inverter of the plurality of inverters and a corresponding motor of the plurality of motors, and wherein each connecting mechanism being configured to disconnect an inverter from a corresponding motor in response to receiving a control signal.
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Abstract
A motor disconnect arrangement is provided for a variable speed drive having a plurality of inverters electrically connected in parallel to a DC link to power a plurality of motors. The disconnect arrangement includes a contactor or other disconnect device connected in series between each inverter output of the variable speed drive and its corresponding motor. The contactor operates to disconnect, isolate or remove the motor from the variable speed drive in the event of a failure of the motor. By removing a failed motor from the variable speed drive, the other motors connected to the variable speed drive can continue to operate normally.
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Citations
24 Claims
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1. A drive system for a plurality of motors comprising:
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a variable speed drive, the variable speed drive comprising; a converter stage to convert an input AC voltage to a DC voltage, the converter stage being configured to be electrically connectable to an AC power source; a DC link stage to filter and store energy from the converter stage, the DC link stage being electrically connected to the converter stage; an inverter stage comprising a plurality of inverters electrically connected in parallel to the DC link stage, each inverter of the plurality of inverters being configured to convert a DC voltage to an output AC voltage to power a corresponding motor of a plurality of motors, and each inverter of the plurality of inverters being configured to operate substantially independently of other inverters of the plurality of inverters; and wherein the converter stage is configured to provide a boosted DC voltage to the DC link stage and each inverter of the plurality of inverters is configured to provide an output AC voltage greater than the input AC voltage; and a plurality of connecting mechanisms, each connecting mechanism of the plurality of connecting mechanisms being connected in series between an inverter of the plurality of inverters and a corresponding motor of the plurality of motors, and wherein each connecting mechanism being configured to disconnect an inverter from a corresponding motor in response to receiving a control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A chiller system comprising:
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a plurality of compressors, each compressor of the plurality of compressors being driven by a corresponding motor, the plurality of compressors being incorporated into at least one refrigerant circuit, each refrigerant circuit comprising at least one compressor of the plurality of compressors, a condenser arrangement and an evaporator arrangement connected in a closed refrigerant loop; a variable speed drive to power the corresponding motors of the plurality of compressors, the variable speed drive being configured to provide an output voltage greater than the input voltage to the variable speed drive, the variable speed drive comprising a converter stage, a DC link stage and an inverter stage, the inverter stage having a plurality of inverters each electrically connected in parallel to the DC link stage and each powering a corresponding motor of a compressor of the plurality of compressors; a plurality of contactors, each contactor of the plurality of contactors being connected in series between an inverter of the plurality of inverters and a corresponding motor of a compressor of the plurality of compressors, and wherein each contactor being configured to enable or disable a connection between the inverter and the corresponding motor of a compressor of the plurality of compressors in response to receiving a control signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A drive system for a multiple compressor chiller system having a plurality of motors, the drive system comprising:
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a variable speed drive, the variable speed drive comprising; a converter stage to convert an input AC voltage to a DC voltage, the converter stage being configured to be electrically connectable to an AC power source; a DC link stage to filter and store energy from the converter stage, the DC link stage being electrically connected to the converter stage; an inverter stage comprising a plurality of inverters electrically connected in parallel to the DC link stage, each inverter of the plurality of inverters being configured to convert a DC voltage to an output AC voltage to power a corresponding motor of a plurality of motors, and each inverter of the plurality of inverters being configured to operate substantially independently of other inverters of the plurality of inverters; and wherein the converter stage is configured to provide a boosted DC voltage to the DC link stage and each inverter of the plurality of inverters is configured to provide an output AC voltage greater than the input AC voltage;
andmeans for isolating a motor of the plurality of motors from other motors of the plurality of motors in response to detecting a fault condition in the motor of the plurality of motors. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification