Variable speed drive for a HVACandR system
Embodiments of the present disclosure relate to a heating, ventilating, air conditioning, and refrigeration (HVAC&R) system that includes a variable speed drive configured to provide power to a motor that drives a compressor of the HVAC&R system and a silicon carbide transistor of the variable speed drive, where the silicon carbide transistor is configured to adjust a voltage, or a frequency, or both of power flowing through the variable speed drive.
1. A heating, ventilating, air conditioning, and refrigeration (HVAC&R) system, comprising:
a variable speed drive configured to provide power to a motor configured to drive a compressor of the HVAC&R system; and
a silicon carbide transistor of the variable speed drive, wherein the silicon carbide transistor is configured to adjust a voltage, or a frequency, or both, of power flowing through the variable speed drive; and
a controller coupled to the silicon carbide transistor and configured to adjust a state of the silicon carbide transistor based on a discharge pressure of the compressor.
2. The system of claim 1 , wherein the variable speed drive comprises:
a rectifier configured to receive alternating current (AC) power from an AC power source and convert the AC power to direct current (DC) power, wherein the AC power comprises a constant voltage and a constant frequency;
a DC bus configured to receive the DC power from the rectifier; and
an inverter configured to receive the DC power from the DC bus and to convert the DC power to AC power having a variable voltage and a variable frequency.
3. The system of claim 1 , wherein the silicon carbide transistor is disposed in the rectifier, or the inverter, or both.
4. The system of claim 2 , wherein the AC power received from the AC power source is three-phase AC power.
5. The system of claim 1 , wherein the silicon carbide transistor is a metal-oxide-semiconductor field-effect transistor (MOSFET).
6. The system of claim 1 , comprising:
the compressor configured to circulate a refrigerant through a refrigerant loop of the HVAC&R system; and
a heat exchanger configured to place the refrigerant in thermal communication with a cooling fluid.
7. The system of claim 6 , comprising an expansion device configured to reduce a pressure of the refrigerant flowing through the refrigerant loop of the HVAC&R system.
8. The system of claim 1 , wherein the controller is configured to adjust the state of the silicon carbide transistor based on the discharge pressure of the compressor and a speed of the motor.
9. A system, comprising:
a compressor of a heating, ventilating, air conditioning, and refrigeration (HVAC&R) system configured to circulate a refrigerant through a refrigerant loop;
a motor configured to drive the compressor of the HVAC&R system;
a variable speed drive configured to provide power to the motor, wherein the variable speed drive comprises a rectifier, a direct current (DC) bus, and an inverter;
a silicon carbide transistor disposed in the rectifier, or the inverter, or both, wherein the silicon carbide transistor is configured to adjust a voltage, or a frequency, or both of alternating current (AC) power in the variable speed drive; and
a controller coupled to the silicon carbide transistor and configured to adjust a state of the silicon carbide transistor based on a discharge pressure of the compressor.
10. The system of claim 9 , wherein the rectifier is configured to receive three-phase alternating current (AC) power from an AC power source and to convert the three-phase AC power to DC power, wherein the AC power is constant voltage and constant frequency.
11. The system of claim 10 , wherein the DC bus is configured to receive the
DC power from the rectifier and to filter or stabilize the DC power.
12. The system of claim 9 , wherein the inverter is configured to receive the DC power from the DC bus and to convert the DC power to AC power having a variable voltage and a variable frequency.
13. The system of claim 9 , wherein the silicon carbide transistor is a metal-oxide-semiconductor field-effect transistor (MOSFET).
14. A method of operating a heating, ventilating, air conditioning, and refrigeration (HVAC&R) system, comprising:
circulating a refrigerant through a refrigerant loop with a compressor;
supplying power to a motor with a variable speed drive, wherein the motor is configured to drive the compressor, and wherein the variable speed drive comprises a silicon carbide transistor; and
adjusting a frequency, or a voltage, or both of power in the variable speed drive using the silicon carbide transistor and based on a discharge pressure of the compressor.
15. The method of claim 14 , comprising adjusting the frequency, or the voltage, or both of the power in the variable speed drive using the silicon carbide transistor and based on the discharge pressure of the compressor and a speed of the motor.