Motor driving apparatus

• US 20050012490A1
• Filed: 07/15/2004
• Published: 01/20/2005
• Est. Priority Date: 07/18/2003
• Status: Active Grant

• Current Assignee: III Holdings 10, LLC (Intellectual Ventures LLC)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakata, Hideki, Ueda, Mitsuo
• Granted Patent: US 7,330,011 B2
• Time in Patent Office: Days
• US Class Current: 318/807
• CPC Class Codes: B41J 19/202 Drive control means for carriage movement
• CPC Class Codes: H02P 25/03 with brushless excitation
• CPC Class Codes: H02P 27/048 using AC supply for only the rotor circuit or only the stator circuit
• CPC Class Codes: H02P 27/08 with pulse width modulation
• CPC Class Codes: H02P 29/50 Reduction of harmonics
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Abstract

A motor driving apparatus includes an inverter circuit for converting an output of a rectifier circuit connected to a single-phase AC power supply into a driving voltage, and outputting the driving voltage to a brushless motor, and an inverter control unit for controlling the amplitude value of the voltage outputted from the inverter to the brushless motor so as to minimize a difference between a command rpm indicated by an external command signal and an actual rpm derived from an estimated phase of the rotor, wherein the command rpm is set to an rpm outside a predetermined range of rpms.

Claims

1. A motor driving apparatus for driving a brushless motor, comprising:

a power conversion circuit for converting an output voltage of an AC power supply into a driving voltage, and outputting the driving voltage to the brushless motor; and

a control unit for controlling the power conversion circuit so that the frequency of an output current of the power conversion circuit is not fixed to a specific frequency.

2. A motor driving apparatus as defined in claim 1 wherein

said AC power supply comprises a single-phase AC power supply, and a rectifier circuit having an input connected to the single-phase AC power supply;

said power conversion circuit has an inverter circuit for converting an output voltage of the rectifier circuit into a driving voltage, and outputting the driving voltage to the brushless motor; and

said control unit is an inverter control unit for controlling the inverter circuit so that the frequency of an output current of the inverter circuit is not fixed to a specific frequency.

3. A motor driving apparatus as defined in claim 2 wherein said specific frequency includes a frequency that is an integral multiple of the frequency of the AC power supply and its vicinity.

4. A motor driving apparatus as defined in claim 2 wherein

said brushless motor is a three-phase brushless motor;

and

said specific frequency is an integral multiple of a frequency that is obtained by multiplying the frequency of the AC power supply by ⅙

.

5. A motor driving apparatus as defined in claim 2 wherein said inverter control unit controls the inverter circuit so that the frequency of the output current of the inverter circuit continuously varies.

6. A motor driving apparatus as defined in claim 5 wherein the frequency of the output current of the inverter circuit varies at random.

7. A motor driving apparatus as defined in claim 2 wherein said power conversion circuit includes a capacitor for charging a regenerative current from the brushless motor, said capacitor being placed upstream from the inverter circuit.

8. A motor driving apparatus as defined in claim 2 wherein said power conversion circuit includes an inductor for cutting noise that occurs in the inverter circuit, said inductor being connected between the inverter circuit and the AC power supply.

9. A motor driving apparatus as defined in claim 1 wherein

said AC power supply comprises a three-phase AC power supply and a three-phase rectifier circuit having an input connected to the three-phase AC power supply;

said voltage conversion circuit has an inverter circuit for converting an output voltage of the three-phase rectifier circuit into a driving voltage, and outputting the driving voltage to the brushless motor; and

said control unit is an inverter controller for controlling the inverter circuit so that the frequency of an output current from the inverter circuit is not fixed to a specific frequency.

10. A motor driving apparatus as defined in claim 1 wherein

said AC power supply is a single-phase AC power supply;

said power conversion circuit is a cycloconverter circuit for converting an output voltage of the single-phase AC power supply into a driving voltage, and outputting the driving voltage to the brushless motor; and

said control unit is a cycloconverter control unit for controlling the cycloconverter circuit so that the frequency of an output current of the cycloconverter circuit is not fixed to a specific frequency.

11. A compressor having a brushless motor, and a motor driving apparatus for driving the brushless motor,

said motor driving apparatus being a motor driving apparatus as defined in claim 1.

12. An air conditioner having a compressor including a brushless motor, and a motor driving apparatus for driving the brushless motor,

said motor driving apparatus being a motor driving apparatus as defined in claim 1.

13. A refrigerator having a compressor including a brushless motor, and a motor driving apparatus for driving the brushless motor,

said motor driving apparatus being a motor driving apparatus as defined in claim 1.

14. An electric washing machine having a brushless motor, and a motor driving apparatus for driving the brushless motor,

said motor driving apparatus being a motor driving apparatus as defined in claim 1.

15. An air blower having a brushless motor, and a motor driving apparatus for driving the brushless motor,

said motor driving apparatus being a motor driving apparatus as defined in claim 1.

16. An electric vacuum cleaner having a brushless motor, and a motor driving apparatus for driving the brushless motor,

said motor driving apparatus being a motor driving apparatus as defined in claim 1.

17. An electric dryer having a compressor including a brushless motor, and a motor driving apparatus for driving the brushless motor,

said motor driving apparatus being a motor driving apparatus as defined in claim 1.

18. A heat pump type hot-water supply unit having a compressor including a brushless motor, and a motor driving apparatus for driving the brushless motor,

said motor driving apparatus being a motor driving apparatus as defined in claim 1.