Motor driving device and air conditioner including the same

Patent metadata

Field	Value
Publication number	US-9625190-B2
Application number	US-201514733601-A
Country	US
Kind code	B2
Filing date	Jun 8, 2015
Priority date	Jun 9, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

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.

First claim

What is claimed is:

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.

Assignees

• Lg Electronics Inc

Inventors

• Lee Jongwan
• Park Gwigeun
• Kim Eungho

Classifications

• F24F11/32

  Responding to malfunctions or emergencies · CPC title

• F25B49/025

  Motor control arrangements · CPC title

• F25B31/02 Primary

  of motor-compressor units · CPC title

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• H02M1/4225

  using a non-isolated boost converter · CPC title