Compressor driving apparatus and home appliance including the same

• US 10,641,533 B2
• Filed: 09/24/2018
• Issued: 05/05/2020
• Est. Priority Date: 09/26/2017
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Cho, Duseok, Kim, Jangsik, Kim, Jaedong
• Primary Examiner(s): Masih, Karen
• Application Number:
  US16/139,316
• Publication Number:
  US 20190093932A1
• Time in Patent Office: Days
• CPC Class Codes: F04B 2203/0201 Current
• CPC Class Codes: F04B 2203/0202 Voltage
• CPC Class Codes: F04B 2203/0209 Rotational speed
• CPC Class Codes: F04B 49/06 Control using electricity regulating by means of floats actuating electric switches F04B49/04
• CPC Class Codes: F04B 49/20 by changing the driving speed
• CPC Class Codes: F25B 2600/021 Inverters therefor
• CPC Class Codes: F25B 2600/112 of evaporator fans
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 2700/2104 of an indoor room or compartment
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: F25B 49/022 Compressor control arrangements
• CPC Class Codes: F25B 49/025 Motor control arrangements
• CPC Class Codes: F25B 5/02 arranged in parallel
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02P 29/0016 Control of angular speed of one shaft without controlling the prime mover
• CPC Class Codes: H02P 29/40 Regulating or controlling the amount of current drawn or delivered by the motor for controlling the mechanical load
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A compressor driving apparatus, or a home appliance including the same, includes a DC terminal capacitor to store a charge, an inverter to convert direct current associated with the charge of the DC terminal capacitor into an alternating current and output the alternating current to a motor, an output current detection unit to detect an output current flowing in the motor, and an inverter controller to increase a motor speed by starting the motor, and controlling a speed increase of the motor to change based on an increasing slope of a change in an output current detected by the output current detection unit during the speed increase of the motor.

Claims

1. A compressor drive of a home appliance having a mechanical expansion valve and a compressor, the compressor drive comprising:

a capacitor that stores a charge;

an inverter that converts direct current associated with the stored charge of the capacitor into alternating current based on a switching control signal, and outputs the alternating current toward a motor;

output current detection circuitry that generates an output current based on the alternating current flowing between the inverter and the motor; and

an inverter controller that generates the switching control signal to;

start the motor, and

control a speed increase of the started motor based on a slope associated with a change in the output current from the output current detection circuitry during the speed increase of the motor,

wherein the inverter controller manages the switching control signal such that a slope associated with the speed increase of the motor is decreased as a difference between a valve-on time of the mechanical expansion valve and a refrigerant discharge time of the compressor increases.

3. The compressor drive of claim 1, wherein the inverter controller manages the switching control signal such that a slope associated with the speed increase of the motor is sequentially decreased based on the slope associated with the change in the output current from the output current detection circuitry when the output current is equal to or greater than a reference value during the speed increase of the motor.

4. The compressor drive of claim 1, wherein the inverter controller manages the switching control signal such that:

a slope associated with the speed increase of the motor is sequentially decreased as the slope associated with the change in the output current from the output current detection circuitry increases, and

a change of the slope associated with the speed increase becomes smaller.

5. The compressor drive of claim 1, wherein the inverter controller manages the switching control signal such that:

a slope associated with the speed increase of the motor switches from a first slope to a second slope that is higher than the first slope during a first interval, and switches to a third slope that is less than the second slope during a second interval after the first interval, when a level of the output current from the output current detection circuitry is equal to or greater than a reference value during the speed increase of the motor.

6. The compressor drive of claim 1, wherein the inverter controller manages the switching control signal such that:

the slope associated with the change in the output current switches from a first slope to a second slope that is less than the first slope during a first interval, and switches to a third slope that is less than the second slope during a second interval after the first interval, when a level of the output current from the output current detection circuitry is equal to or greater than a reference value during the speed increase of the motor.

7. The compressor drive of claim 1, further comprising a DC terminal voltage detection circuitry that detects a DC terminal voltage associated with the capacitor,

wherein the inverter controller calculates a first period in which the output current reaches a tolerance value based on the DC terminal voltage detected by the DC terminal voltage detection circuitry and a rotor position of the motor, and calculates the slope associated with a speed increase of the motor based on the calculated first period.

8. The compressor drive of claim 7, wherein the first period in which the output current reaches the tolerance value becomes longer as the slope associated with the speed increase of the motor is decreased.

9. The compressor drive of claim 7, wherein the inverter controller includes:

a timing calculator to calculate the first period in which the output current reaches the tolerance value based on the DC terminal voltage detected by the DC terminal voltage detection circuitry and the rotor position of the motor; and

a speed slope calculator to calculate the slope of the speed increase of the motor based on the calculated first period.

10. The compressor drive of claim 9, wherein the inverter controller includes:

a current command generator to generate a current command value based on the calculated slope of the speed increase of the motor and a speed command value;

a voltage command generator to generate a voltage command value based on the generated current command value; and

a switching control signal output unit to output the switching control signal to the inverter based on the voltage command value.

11. The compressor drive of claim 9, wherein the speed slope calculator decreases the slope associated with the speed increase of the motor as the calculated first period decreases.

12. The compressor drive of claim 9, wherein the speed slope calculator decreases the slope associated with the speed increase of the motor as the calculated first period decreases.

13. The compressor drive of claim 9, wherein the speed slope calculator decreases the slope associated with the speed increase of the motor from a first slope to a second slope, which is less than the first slope, during a first interval, and from the second slope to a third slope, which is less than the second slope, during a second interval after the first interval.

14. The compressor drive of claim 1, wherein the inverter controller manages the switching control signal such that a slope associated with the speed increase of the motor is increased when a weak field control is performed during the speed increase of the motor.

2. Circuitry to drive a compressor in a home appliance, the circuitry comprising:

a direct current source that provides a direct current;

an inverter that converts the direct current into alternating current based on a switching control signal, and outputs the alternating current to a motor of the compressor;

output current detection circuitry that generates an output current based on the alternating current between the inverter and the motor; and

an inverter controller that generates the switching control signal to start the motor and to control a speed increase of the motor based on a rate of a change over time associated with the output current from the output current detection circuitry during the speed increase of the motor,

wherein the inverter controller manages the switching control signal such that a rate of change over time associated with the speed increase of the motor is decreased based on the rate of change over time associated with the output current from the output current detection circuitry when the output current is equal to or greater than a reference value during the speed increase of the motor.

21. The circuitry of claim 2, wherein the direct current source includes:

a rectifier to rectify alternating current from a voltage source; and

a capacitor to smooth the rectified alternating current to form the direct current provided to the inverter.

15. A home appliance comprising:

a mechanical expansion valve;

a compressor; and

a compressor drive that includes;

a capacitor that stores a charge;

an inverter that converts direct current associated with the stored charge of the capacitor into alternating current based on a switching control signal, and outputs the alternating current toward a motor;

output current detection circuitry that generates an output current based on the alternating current flowing between the inverter and the motor; and

an inverter controller that generates the switching control signal to;

start the motor, and

control a speed increase of the started motor based on a slope associated with a change in the output current from the output current detection circuitry during the speed increase of the motor,

wherein the inverter controller manages the switching control signal such that a slope associated with the speed increase of the motor is decreased as a difference between a valve-on time of the mechanical expansion valve and a refrigerant discharge time of the compressor increases.

16. The home appliance of claim 15, wherein the inverter controller manages the switching control signal such that a slope associated with the speed increase of the motor is decreased based on the slope associated with the change in the output current from the output current detection circuitry when the output current is equal to or greater than a reference value during the speed increase of the motor.

17. The home appliance of claim 15, wherein the inverter controller manages the switching control signal such that:

a slope associated with the speed increase of the motor is sequentially decreased as the slope associated with the change in the output current from the output current detection circuitry increases, and

a change of the slope associated with the speed increase becomes smaller.

18. The home appliance of claim 15, wherein the inverter controller manages the switching control signal such that:

a slope associated with the speed increase of the motor switches from a first slope to a second slope that is higher than the first slope during a first interval, and switches to a third slope that is less than the second slope during a second interval after the first interval, when a level of the output current from the output current detection circuitry is equal to or greater than a reference value during the speed increase of the motor.

19. The home appliance of claim 15, wherein the inverter controller manages the switching control signal such that:

the slope associated with the change in the output current switches from a first slope to a second slope that is less than the first slope during a first interval, and switches to a third slope that is less than the second slope during a second interval after the first interval, when a level of the output current from the output current detection circuitry is equal to or greater than a reference value during the speed increase of the motor.

20. The home appliance of claim 15, wherein the compressor drive further includes a DC terminal voltage detection circuitry that detects a DC terminal voltage associated with the capacitor,

wherein the inverter controller calculates a first period in which the output current reaches a tolerance value based on the DC terminal voltage detected by the DC terminal voltage detection circuitry and a rotor position of the motor, and calculates a slope associated with the speed increase of the motor based on the calculated first period.