HVAC motor load balancing

Patent metadata

Field	Value
Publication number	US-9528718-B2
Application number	US-201214237946-A
Country	US
Kind code	B2
Filing date	Aug 6, 2012
Priority date	Aug 10, 2011
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A method of motor operation includes monitoring a voltage of a power bus supplying power to the motor, determining if a power failure is occurring or has occurred based on the monitoring, and lowering an operational capacity of the motor in response to the determining.

First claim

The invention claimed is:

1. A method of motor operation, comprising:
monitoring a voltage of a power bus supplying power to the motor;
determining if a power failure is occurring or has occurred based on the monitoring;
determining an existing voltage of the power bus in response to the determining if the power failure is occurring or has occurred based on the monitoring; and
lowering an operational capacity of the motor to a lowered operational capacity in response to the determining the existing voltage, wherein the lowered operational capacity of the motor is based upon the existing voltage.

2. The method of claim 1 , wherein the lowered operational capacity of the motor is based upon predetermined discharge rates of the motor under a power failure.

3. The method of claim 1 , further comprising determining if power has been restored, and, if power is restored, increasing the operational capacity of the motor.

4. The method of claim 3 , wherein increasing the operational capacity of the motor includes increasing the operational capacity of the motor to one of a standard steady-state operational capacity or a reduced steady-state operational capacity.

5. The method of claim 1 , further comprising determining if the existing voltage of the power bus is below a predetermined threshold, and, if the existing voltage of the power bus is below the predetermined threshold, shutting down the motor.

6. The method of claim 1 , further comprising determining if the existing voltage of the power bus is below a predetermined threshold, and, if the existing voltage of the power bus is not below the predetermined threshold, continually reducing the operational capacity of the motor at regular intervals until the existing voltage of the power bus is below the predetermined threshold.

7. The method of claim 1 , further comprising determining if the existing voltage of the power bus is below a predetermined threshold, and, if the existing voltage of the power bus is not below the predetermined threshold, maintaining the reduced operational capacity of the motor until the existing voltage of the power bus is below the predetermined threshold.

8. The method of claim 1 , wherein determining if a power failure is occurring or has occurred includes determining if the voltage of the power bus has decreased below a nominal powered level.

9. The method of claim 1 , wherein the motor is a component of a HVAC system.

10. A system, comprising:
a system controller;
a variable frequency drive (VFD) in communication with the system controller; and
a motor in communication with the VFD;
wherein the VFD is configured to monitor a voltage of a power bus arranged therein to determine if a power failure has occurred or is occurring, and wherein the VFD is configured to reduce a speed of the motor in response to the determining, wherein the reduced speed of the motor is based upon the voltage of the power bus.

11. The system of claim 10 , wherein the VFD is further configured to determine if power to the system has been restored, and, if power is restored, the VFD is configured to increase the speed of the motor.

12. The system of claim 10 , wherein the VFD is further configured to determine if the voltage of the power bus is below a predetermined threshold, and, if the voltage of the power bus is below the predetermined threshold, the VFD is configured to direct the system controller to shut down the motor or system.

13. The system of claim 10 wherein the VFD is further configured to determine if the voltage of the power bus is below a predetermined threshold, and, if the voltage of the power bus is not below the predetermined threshold, the VFD is configured to continually reduce the speed of the motor until the voltage of the power bus is below the predetermined threshold.

14. A heating, ventilation, and air conditioning (HVAC) system, comprising:
an HVAC system controller;
a variable frequency drive (VFD) in communication with the HVAC system controller; and
a motor in communication with the VFD;
wherein the HVAC system controller is configured to monitor a voltage of a power bus arranged within the VFD to determine if a power failure has occurred or is occurring, and wherein the VFD is configured to reduce a speed of the motor in response to the determining by the HVAC controller, wherein the reduced speed of the motor is based upon the voltage of the power bus.

15. The system of claim 14 , wherein the HVAC system controller is further configured to determine if power to the HVAC system has been restored, and, if power is restored, the HVAC system controller is configured to direct the VFD to increase the speed of the motor.

16. The system of claim 14 , wherein the HVAC system controller is further configured to determine if the voltage of the power bus is below a predetermined threshold, and, if the voltage of the power bus is below the predetermined threshold, the HVAC system controller is configured shut down the HVAC system.

17. The system of claim 14 , wherein the HVAC system controller is further configured to determine if the voltage of the power bus is below a predetermined threshold, and, if the voltage of the power bus is not below the predetermined threshold, the HVAC system controller is configured to direct the VFD to continually reduce the speed of the motor until the voltage of the power bus is below the predetermined threshold.

Assignees

• De Tathagata
• Carrier Corp

Inventors

• De Tathagata

Classifications

• F24F11/37 Primary

  Resuming operation, e.g. after power outages; Emergency starting · CPC title

• F24F11/30 Primary

  for purposes related to the operation of the system, e.g. for safety or monitoring · CPC title

• H02P29/025

  the fault being a power interruption · CPC title

• H02P27/04 Primary

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

• H02P29/026

  the fault being a power fluctuation · CPC title