Variable speed drive with secondary windings

Patent metadata

Field	Value
Publication number	US-11512885-B2
Application number	US-201716338974-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Oct 5, 2016
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

Embodiments of the present disclosure relate to a refrigeration system that includes a compressor configured to circulate refrigerant along a refrigerant loop, a motor configured to drive the compressor, and a variable speed drive coupled to the motor and configured to supply power to the motor. The variable speed drive includes a primary winding of a step down transformer coupled to an alternating current (AC) power source, a first secondary winding of the step down transformer, where the first secondary winding is configured to supply power at a variable supplied voltage to the motor when the motor operates below a threshold voltage, and a second secondary winding of the step down transformer, where the second secondary winding is configured to supply power at a fixed supplied voltage when the motor operates at or above the threshold voltage.

First claim

The invention claimed is:

1. A refrigeration system, comprising:
a compressor configured to circulate refrigerant through a refrigerant loop;
a motor configured to drive the compressor; and
a variable speed drive coupled to the motor and configured to supply power to the motor, wherein the variable speed drive comprises:
a primary winding of a step down transformer coupled to an alternating current (AC) power source;
a first secondary winding of the step down transformer, wherein the first secondary winding is configured to supply power to the motor at a variable supplied voltage to operate the motor below a threshold voltage; and
a second secondary winding of the step down transformer, wherein the second secondary winding is configured to supply power to the motor at a fixed supplied voltage to operate the motor at or above the threshold voltage.

2. The refrigeration system of claim 1 , wherein the variable speed drive comprises:
a rectifier coupled to the first secondary winding, wherein the rectifier is configured to convert a fixed voltage from the AC power source into direct current (DC) power;
a DC link coupled to the first secondary winding, wherein the DC link is configured to filter the DC power from the rectifier, or store the DC power from the rectifier, or both; and
an inverter coupled to the first secondary winding, wherein the inverter is configured to convert the DC power from the DC link into variable voltage AC power and supply the variable voltage AC power to the motor.

3. The refrigeration system of claim 1 , wherein the second secondary winding is rated for a fixed speed mains voltage rating of the motor.

4. The refrigeration system of claim 1 , wherein the primary winding is rated for up to 15,000 Volts (V).

5. The refrigeration system of claim 1 , comprising:
a condenser disposed along the refrigerant loop, wherein the condenser is configured to receive refrigerant from the compressor and place the refrigerant in a first heat exchange relationship with a cooling fluid, such that the refrigerant condenses to a liquid refrigerant; and
an evaporator disposed along the refrigerant loop, wherein the evaporator is configured to receive the liquid refrigerant from the condenser and place the liquid refrigerant in a second heat exchange relationship with a heating fluid, such that the liquid refrigerant evaporates into a vapor refrigerant.

6. The refrigeration system of claim 1 , wherein the primary winding is coupled to a three-phase AC power source.

7. The refrigeration system of claim 6 , wherein the three-phase AC power source supplies power having up to 15 kilovolts (kV) and a frequency between 50 Hertz (Hz) and 60 Hz.

8. The refrigeration system of claim 1 , comprising:
a first circuit comprising the first secondary winding, the motor, and a first switch;
a second circuit comprising the second secondary winding, the motor, and a second switch; and
a controller communicatively coupled to the first switch of the first circuit and the second switch of the second circuit.

9. The refrigeration system of claim 8 , wherein the controller is configured to close the first switch and open the second switch when the motor operates below the threshold voltage, and wherein the controller is configured to open the first switch and close the second switch when the motor operates at or above the threshold voltage.

10. A system, comprising:
a variable speed drive coupled to a motor and configured to supply power to the motor, wherein the variable speed drive comprises:
a primary winding of a step down transformer coupled to an alternating current (AC) power source;
a first secondary winding of the step down transformer, wherein the first secondary winding is configured to supply power to the motor at a variable supplied voltage to operate the motor below a threshold voltage; and
a second secondary winding of the step down transformer, wherein the second secondary winding is configured to supply power to the motor at a fixed supplied voltage to operate the motor at or above the threshold voltage; and

a controller configured to selectively establish electrical communication between the motor and the first secondary winding and between the motor and the second secondary winding based on a measured voltage of the motor.

11. The system of claim 10 , wherein the variable speed drive comprises:
a rectifier coupled to the first secondary winding, wherein the rectifier is configured to convert a fixed voltage from the AC power source into direct current (DC) power;
a DC link coupled to the first secondary winding, wherein the DC link is configured to filter the DC power from the rectifier, store the DC power from the rectifier, or a combination thereof; and
an inverter coupled to the first secondary winding, wherein the inverter is configured to convert the DC power from the DC link into variable voltage AC power and supply the variable voltage AC power to the motor.

12. The system of claim 11 , comprising:
a first circuit comprising the first secondary winding, the rectifier, the DC link, the inverter, the motor, and a first switch; and
a second circuit comprising the second secondary winding, the motor, and a second switch.

13. The system of claim 12 , wherein the controller is electrically coupled to the first switch of the first circuit and the second switch of the second circuit, wherein the controller is configured to close the first switch and open the second switch when the measured voltage of the motor is below the threshold voltage, and wherein the controller is configured to open the first switch and close the second switch when the measured voltage of the motor is at or above the threshold voltage.

14. The system of claim 10 , comprising the motor and an additional motor, wherein the variable speed drive is coupled to the additional motor and is configured to supply power to the additional motor.

15. The system of claim 14 , wherein the controller is configured to establish an electrical connection between the additional motor and the first secondary winding when an electrical connection between the motor and the second secondary winding is established.

16. The system of claim 10 , wherein the second secondary winding is rated for 4160 Volts (V).

17. A method, comprising:
monitoring a voltage demand of a motor, wherein a variable speed drive is coupled to the motor and configured to supply power to the motor;
supplying a first power to the motor from a first secondary winding of the variable speed drive to operate the motor based on the voltage demand of the motor being below a threshold, wherein the first power comprises a variable voltage; and
supplying a second power to the motor from a second secondary winding of the variable speed drive to operate the motor based on the voltage demand of the motor being at or above the threshold, wherein the second power comprises a constant voltage, and wherein the second secondary winding is integral with the variable speed drive.

18. The method of claim 17 , comprising switching from the first power to the second power when the voltage demand of the motor reaches the threshold.

19. The method of claim 18 , wherein switching from the first power to the second power comprises opening a first switch of a first circuit and closing a second switch of a second circuit when the voltage demand of the motor reaches the threshold, wherein the first circuit comprises the first secondary winding, the motor, and the first switch, and wherein the second circuit comprise

Assignees

• Johnson Controls Tech Co
• Johnson Controls Tyco IP Holdings LLP

Inventors

• Saylor David F

Classifications

• H02P27/04

  using variable-frequency supply voltage, e.g. inverter or converter supply voltage · CPC title

• F04D15/0066

  by changing the speed, e.g. of the driving engine · CPC title

• F04D27/0261

  by varying driving speed · CPC title

• F04B49/20

  by changing the driving speed · CPC title

• F04B49/02

  Stopping, starting, unloading or idling control · CPC title