Air conditioner

Patent metadata

Field	Value
Publication number	US-10989433-B2
Application number	US-201415529115-A
Country	US
Kind code	B2
Filing date	Nov 26, 2014
Priority date	Nov 26, 2014
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

An air conditioner 1 includes: an outdoor heat exchanger 14 ; an outdoor fan 12 for blowing air to the outdoor heat exchanger; an outdoor fan motor 20 that drives the outdoor fan; an outdoor fan inverter 21 that drives the outdoor fan motor; and a control unit 31 that generates a rotation-speed command voltage for controlling the rotation number of the outdoor fan motor. In addition, the control unit starts a defrost operation of the outdoor heat exchanger, based on the rotation-speed command voltage. In this manner, it is possible to achieve an outdoor device of an air conditioner in which there is no need to provide a current detecting sensor, and it is possible to detect frost formation over the heat exchanger during a heating operation and to perform a defrost operation at low costs.

First claim

The invention claimed is:

1. An air conditioner comprising:
an outdoor heat exchanger;
an outdoor fan for blowing air to the outdoor heat exchanger;
an outdoor fan motor that drives the outdoor fan;
an outdoor fan inverter that drives the outdoor fan motor; and
a controller, connected to the fan inverter, that generates a rotation-speed command voltage for controlling a rotation number of the outdoor fan motor to be constant,
wherein an actual rotation number of the outdoor fan is subject to feedback to the fan inverter and the fan inverter transmits the actual rotation number to the controller,
wherein the controller compares the actual rotation number to a target rotation number of the outdoor fan and adjusts the rotation-speed command voltage by increasing or decreasing the rotation-speed command voltage based on the comparison of the actual rotation number and the target rotation number,
wherein the adjusted rotation-speed command voltage is output from the controller to the fan inverter and the fan inverter converts the adjusted rotation-speed command voltage and a DC voltage into AC voltage and the inverter outputs the AC voltage to the outdoor fan, and
wherein the controller, upon determining the adjusted rotation-speed command voltage is greater than a predetermined threshold, starts a defrost operation of the outdoor heat exchanger.

2. The air conditioner according to claim 1 ,
wherein, as the target rotation number of the outdoor fan increases, or as the rotation-speed command voltage with respect to the target rotation number of the outdoor fan increases, the predetermined value increases.

3. The air conditioner according to claim 1 ,
wherein the fan motor of the outdoor fan is provided with the outdoor fan inverter.

4. The air conditioner according to claim 1 ,
wherein a first reference value (A 1 base) and a second reference value (A 2 base) that is smaller than the first reference value are set as rotation-speed command voltages of a no-frost-formation state, corresponding to a first target rotation number (f 1 ) and a second target rotation number (f 2 ) that is smaller than the first target rotation number of the outdoor fan motor, respectively,
wherein a first defrost determination value (A 1 def) that is larger than the first reference value is set as a rotation-speed command voltage of a frost-formation state, corresponding to the first target rotation number of the outdoor fan motor, and further a second defrost determination value (A 2 def) that is larger than the second reference value and smaller than the first defrost determination value is set as a rotation-speed command voltage of a frost-formation state, corresponding to the second target rotation number of the outdoor fan motor, and
wherein the controller starts the defrost operation of the outdoor heat exchanger when the rotation number of the outdoor fan motor is equal to the first target rotation number during a heating operation and the rotation-speed command voltage is larger than or equal to the first defrost determination value, and the controller starts the defrost operation of the outdoor heat exchanger when the rotation number of the outdoor fan motor is equal to the second target rotation number and the rotation-speed command voltage is larger than or equal to the second defrost determination value.

5. The air conditioner according to claim 4 , further comprising:
a memory of the controller that stores the first and second target rotation numbers, the first and second reference values, and the first and second defrost determination values,
wherein a reference value of a rotation-speed command voltage of a no-frost-formation state and a defrost determination value of a rotation-speed command voltage of a frost-formation state, which corresponds to target rotation numbers other than the target rotation number stored in the storage unit, are calculated, based on the target rotation numbers, the reference values, and the defrost determination values stored in the memory.

6. An air conditioner comprising:
an outdoor heat exchanger;
an outdoor fan for blowing air to the outdoor heat exchanger;
an outdoor fan motor that drives the outdoor fan;
an outdoor fan inverter that drives the outdoor fan motor; and
a controller, connected to the fan inverter, that generates a rotation-speed command voltage for controlling a rotation number of the outdoor fan motor to be constant,
wherein an actual rotation number of the outdoor fan is subject to feedback to the fan inverter and the fan inverter transmits the actual rotation number to the controller,
wherein the controller compares to the actual rotation number to a target rotation number of the outdoor fan and adjusts the rotation-speed command voltage by increasing or decreasing the rotation-speed command voltage based on the comparison of the actual number and the target rotation number
wherein the adjusted rotation-speed command voltage is output from the controller to the fan inverter and the fan inverter converts the adjusted rotation-speed command voltage and a DC voltage into AC voltage and the inverter outputs the AC voltage to the outdoor fan, and
wherein the controller, upon determining a duty ratio for generating the rotation-speed command voltage is greater than a predetermined threshold, starts the defrost operation of the outdoor heat exchanger.

7. The air conditioner according to claim 6 ,
wherein a first reference value (C 1 base or D 1 base) and a second reference value (C 2 base or D 2 base) that is smaller than the first reference value are set as duty ratios or respective increase rates of a duty ratio of a no-frost-formation state, corresponding to a first target rotation number (m 1 or n 1 ) and a second target rotation number (m 2 or n 2 ) that is smaller than the first target rotation number of the outdoor fan motor, respectively,
wherein a first defrost determination value (C 1 def or D 1 def) that is larger than the first reference value is set as a duty ratio or an increase rate of a duty ratio of a frost-formation state, corresponding to the first target rotation number of the outdoor fan motor, and further a second defrost determination value (C 2 def or D 2 def) that is larger than the second reference value and smaller than the first defrost determination value is set as a duty ratio or an increase rate of a duty ratio of a frost-formation state, corresponding to the second target rotation number of the outdoor fan motor, and
wherein the controller starts the defrost operation of the outdoor heat exchanger when the rotation number of the outdoor fan motor is equal to the first target rotation number during a heating operation and the duty ratio or the increase rate of the duty ratio is larger than or equal to the first defrost determination value in the frost-formation state, and the controller starts the defrost operation of the outdoor heat exchanger when the rotation number of the outdoor fan motor is equal to the second target rotation number and the duty ratio or the increase rate of the duty ratio is larger than or equal to the second defrost determination value in the frost-formation state.

8. The air conditioner according to claim 7 , further comprising:
a memory of the controller that stores the first and second target rotation numbers, the first and second reference values, and the first and second defrost determination values,
wherein a reference value of a duty ratio or an increase rate of a duty ratio of a no-frost-formation state and a defrost determination value of a duty ratio or an increase rate of a duty ratio of a frost-formation state, which corresponds to target rotation numbers other than the target rotation number stored in the memory, are calculated

Assignees

• Johnson Controls Hitachi Air Conditioning Tech Hong Kong Limited
• Hitachi Johnson Controls Air Conditioning Inc

Inventors

• Suzuki Natsuko
• Naito Koji
• Matsumura Kenji
• Urata Kazumoto

Classifications

• F25B2700/173

  of the evaporator fan · CPC title

• F24F11/30

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

• F25B2313/0294

  related to the outdoor fan, e.g. controlling speed · CPC title

• F24F11/65

  for selecting an operating mode · CPC title

• F24F11/89 Primary

  Arrangement or mounting of control or safety devices · CPC title