Back to results
US 2014/0271232 A1Published application
System and method for controlling compressor motor voltage
AssigneeJohnson Controls Technology Company
InventorWilliam L. KOPKO
Life of this patent
Estimating the term…
Abstract
A variable speed drive (VSD) can be used to vary the voltage-to-frequency ratio (V/f) supplied to a compressor motor of a heating, ventilation, air conditioning or refrigeration (HVAC&R) system to compensate for varying conditions in the HVAC&R system.
Claims20
A method for controlling compressor motor voltage, the method comprising:
- calculating a motor current based on an operating frequency of a compressor motor operating at a predetermined volts/frequency ratio;
- calculating a first current/volts ratio based on the calculated motor current, the operating frequency and the predetermined volts/frequency ratio;
- calculating a second current/volts ratio based on a measured motor current, the operating frequency and the predetermined volts/frequency ratio;
- comparing the calculated first current/volts ratio to the calculated second current/volts ratio;
- and
- adjusting a voltage provided to the compressor motor by a variable speed drive in response to the calculated first current/volts ratio being unequal to the calculated second current/volts ratio.
3 more elements
A system comprising:
- a compressor, a condenser, an expansion device and an evaporator connected in a closed refrigerant circuit;
- a motor connected to the compressor to power the compressor;
- a variable speed drive connected to the motor to power the motor, the variable speed drive being operable to provide a variable voltage to the motor and a variable frequency to the motor;
- a control panel to control operation of the variable speed drive and one or more components of the system;
- a sensor to measure a current for the motor, the sensor communicating the measured motor current to the control panel;
- and
- the control panel executing a control algorithm with the measured motor current as an input to adjust a voltage provided to the motor by the variable speed drive in order to operate the motor at a current/volts ratio stored in a memory device.
4 more elements
Dependencies are inferred from the claim text.