Variable speed drive control for chiller coast-through
First Claim
1. A chiller system comprising:
- a compressor, a condenser and an evaporator in fluid communication;
a motor connected to the compressor to drive the compressor;
a variable speed drive for powering the motor; and
a control panel configured to;
deactivate the variable speed drive in response to sensing that an input power to the chiller system is less than a predetermined threshold;
determine that the input power has been restored in response to sensing that the input power is greater than or equal to the predetermined threshold;
determine a motor rotation and motor rotational speed; and
in response to determining that the input power is restored and the motor is rotating in a forward direction, reactivate the variable speed drive.
3 Assignments
0 Petitions
Accused Products
Abstract
A chiller system includes a compressor, a condenser and an evaporator in fluid communication. A motor drives the compressor. A variable speed drive powers the motor. An oil heater and pump system circulate heated lubricating oil in the compressor. A control panel is arranged to determine whether an input parameter is greater than or equal to a threshold parameter; deactivate the VSD in response to sensing that the input parameter is less than the threshold parameter; determine at least one chiller capacity control parameter at a point when the VSD is deactivated, and maintain the at least one chiller capacity control parameter while the VSD is deactivated; determine that the input parameter has been restored; determine a motor rotation and motor rotational speed; and in response to determining that the input parameter is restored and the motor is rotating in a forward direction, reactivate the VSD.
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Citations
16 Claims
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1. A chiller system comprising:
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a compressor, a condenser and an evaporator in fluid communication; a motor connected to the compressor to drive the compressor; a variable speed drive for powering the motor; and a control panel configured to; deactivate the variable speed drive in response to sensing that an input power to the chiller system is less than a predetermined threshold; determine that the input power has been restored in response to sensing that the input power is greater than or equal to the predetermined threshold; determine a motor rotation and motor rotational speed; and in response to determining that the input power is restored and the motor is rotating in a forward direction, reactivate the variable speed drive. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 14)
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11. A control system for a chiller system comprising:
a control panel, the control panel configured to; deactivate a variable speed drive in response to sensing that an input power to the chiller system is less than a predetermined threshold; determine that the input power is restored when the input power is greater than or equal to the predetermined threshold; determine a motor rotation and motor rotational speed; and in response to determining that the input power is restored and the motor is rotating in the forward direction; set an output frequency of the variable speed drive to approximately equal the motor rotational speed; and increase the output frequency of the variable speed drive and the motor rotational speed to approximately equal a predetermined motor rotational speed. - View Dependent Claims (12, 13)
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15. A centrifugal chiller system comprising:
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a motor configured to drive a centrifugal compressor of the centrifugal chiller system; a variable speed drive coupled to terminals of the motor and configured to supply power to the motor; and a control panel configured to; measure an input power to the centrifugal chiller system; in response to determining that the input power is less than a predetermined threshold, signal the variable speed drive to deactivate the motor by removing a first current supplied to the terminals of the motor; in response to determining that the input power has been restored to greater than or equal to the predetermined threshold, measure a voltage and a phase of a second current at the terminals of the motor and determine a motor rotational direction; and in response to determining a forward motor rotational direction when the input power has been restored, signal the variable speed drive to apply a third current having the measured voltage and the measured phase to the terminals of the motor to reactivate the motor. - View Dependent Claims (16)
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Specification