Motor driving device and air conditioner including the same

• US 9,625,190 B2
• Filed: 06/08/2015
• Issued: 04/18/2017
• Est. Priority Date: 06/09/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Jongwan, Park, Gwigeun, Kim, Eungho
• Primary Examiner(s): Ismail, Shawki S
• Assistant Examiner(s): Islam, Muhammad S
• Application Number:
  US14/733,601
• Publication Number:
  US 20150354870A1
• Time in Patent Office: 680 Days
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/32 Responding to malfunctions or emergencies
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/005 Outdoor unit expansion valves
• CPC Class Codes: F25B 2313/006 two pipes connecting the outdoor side to the indoor side with multiple indoor units
• CPC Class Codes: F25B 2313/02741 using one four-way valve
• CPC Class Codes: F25B 2600/021 Inverters therefor
• CPC Class Codes: F25B 2700/151 of the compressor motor
• CPC Class Codes: F25B 31/02 of motor-compressor units
• CPC Class Codes: F25B 49/025 Motor control arrangements
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H02P 5/74 controlling two or more ac dynamo-electric motors H02P5/46, H02P5/60 take precedence
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A motor driving device and an air conditioner including the same are disclosed. The motor driving device includes a rectifier to rectify input AC power, a boost converter for boosting the rectified power from the rectifier, a first capacitor to store a pulsating voltage from the boost converter, a first inverter for outputting, to a compressor motor, AC power transformed using a voltage across the first capacitor, a second capacitor to store the rectified power from the rectifier, a second inverter for outputting, to a first fan motor, AC power transformed using a voltage across the second capacitor, and a voltage dropper to drop the voltage across the second capacitor, and to output the dropped voltage. In accordance with this configuration, the compressor motor and fan motor can be driven, using the same input AC power, even though the motor driving device uses a low-capacitance capacitor.

Claims

1. A motor driving device comprising:

a rectifier to rectify input alternate current (AC) power;

a boost converter to boost the rectified power from the rectifier, and to provide boosted power;

a first capacitor to store a pulsating voltage from the boost converter;

a first inverter that includes a plurality of switching elements, the first inverter to provide, to a compressor motor, AC power transformed using the pulsating voltage across the first capacitor;

a second capacitor to store voltage from the rectifier, wherein a capacitance of the first capacitor is less than a capacitance of the second capacitor;

a second inverter that includes a plurality of switching elements, the second inverter to provide, to a first fan motor, AC power transformed using a voltage across the second capacitor; and

a voltage dropper to drop the voltage across the second capacitor, and to provide the dropped voltage as operating voltages of the first inverter and the second inverter,

wherein the boost converter outputs the pulsating voltage having a first voltage level and a peak voltage level of the input AC power.

2. The motor driving device according to claim 1, further comprising:

a fan switching element between a power source of the input AC power and the rectifier, wherein a second fan motor is driven based on operation of the fan switching element.

3. The motor driving device according to claim 1, wherein a voltage in the first capacitor is higher than a voltage in the second capacitor.

4. The motor driving device according to claim 1, wherein the first capacitor is a film capacitor.

5. The motor driving device according to claim 1, wherein the boost converter includes:

an inductor and a diode connected in series between the rectifier and a node of the first capacitor; and

a switching element connected to a node between the inductor and the diode.

6. The motor driving device according to claim 1, further comprising:

an input current detector to detect input current from the input AC power;

an input voltage detector to detect input voltage from the input AC power; and

a converter controller to provide, based on the detected input current and the detected input voltage, a converter control signal to control a switching element of the boost converter.

7. The motor driving device according to claim 1, further comprising:

a direct current (DC) link voltage detector, between the boost converter and the first inverter, to detect a first DC link voltage;

an output current detector to detect an output current flowing to the compressor motor; and

an inverter controller to control the first inverter, based on the detected DC link voltage and the detected output current.

8. The motor driving device according to claim 6, wherein the converter controller includes:

an input current command generator to provide, based on the detected input voltage, an input current command value; and

a current controller to provide a first switching control signal, based on the detected input current and the input current command value.

9. The motor driving device according to claim 8, wherein:

the converter controller further includes a feed-forward compensator to provide a second switching control signal; and

the converter controller provides the converter switching control signal, based on the first switching control signal and the second switching control signal.

10. An air conditioner comprising:

a compressor to compress refrigerant;

a heat exchanger to perform heat exchange using the compressed refrigerant; and

a compressor motor driving device to drive a compressor motor,

wherein the compressor motor driving device includes;

a rectifier to receive alternate current (AC) power;

a boost converter to boost power from the rectifier, and to provide the boosted power;

a first capacitor to store a pulsating voltage from the boost converter;

a first inverter to receive the pulsating voltage from the first capacitor, and to provide transformed AC power to the compressor motor;

a second capacitor to store power from the rectifier, wherein a capacitance of the first capacitor is less than a capacitance of the second capacitor;

a second inverter to receive voltage from the second capacitor, and to provide transformed AC power to a first fan motor; and

a voltage dropper to drop the voltage across the second capacitor, and to provide the dropped voltage as operating voltages of the first inverter and the second inverter,

wherein the boost converter outputs the pulsating voltage having a first voltage level and a peak voltage level of the input AC power.

11. The air conditioner according to claim 10, wherein the compressor motor driving device further includes:

a fan switching element between a power source of the input AC power and the rectifier, wherein the fan switching element to control operation of a second fan motor.

12. The air conditioner according to claim 10, wherein a voltage in the first capacitor is higher than a voltage in the second capacitor.

13. The air conditioner according to claim 10, wherein the first capacitor is a film capacitor.

14. The air conditioner according to claim 10, wherein the boost converter includes:

an inductor and a diode connected in series between the rectifier and a node of the first capacitor; and

a switching element connected to a node between the inductor and the diode.

15. The air conditioner according to claim 10, wherein the compressor motor driving device further includes:

an input current detector to detect input current from the received AC power;

an input voltage detector to detect input voltage from the received AC power; and

a converter controller to provide a converter control signal to control a switching element of the boost converter, based on the detected input current and the detected input voltage.

16. The air conditioner according to claim 10, wherein the compressor motor driving device further includes:

a direct current (DC) link voltage detector, between the boost converter and the first inverter, to detect a first DC link voltage between the boost converter and the first inverter;

an output current detector to detect an output current to the compressor motor; and

an inverter controller to control the first inverter, based on the detected DC link voltage and the detected output current.

17. The air conditioner according to claim 15, wherein the converter controller includes:

an input current command generator to provide, based on the detected input voltage, an input current command value; and

a current controller to provide a first switching control signal, based on the detected input current and the input current command value.

18. The air conditioner according to claim 17, wherein:

the converter controller further includes a feed-forward compensator to provide a second switching control signal; and

the converter controller provides the converter switching control signal, based on the first switching control signal and the second switching control signal.