POWER CONVERTER

• US 20140232309A1
• Filed: 09/28/2012
• Published: 08/21/2014
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Maeda, Toshiyuki, Zhou, Yueqiang
• Granted Patent: US 9,287,815 B2
• Time in Patent Office: Days
• US Class Current: 318/400.02
• CPC Class Codes: H02P 21/05 specially adapted for damping motor oscillations, e.g. for reducing hunting
• CPC Class Codes: H02P 21/06 Rotor flux based control involving the use of rotor position or rotor speed sensors
• CPC Class Codes: H02P 27/08 with pulse width modulation

Abstract

In a power converter, vibration and noise of a motor due to pulsation of a direct current link voltage are reduced. An inverter circuit is provided, which is configured to convert a direct current link voltage having a pulsating component to an alternating current to output the alternating current to a permanent magnet synchronous motor. A controller is provided, which is configured to control the inverter circuit by vector control and which, in a control state in which fundamental voltage vectors do not include a zero vector (voltage vector for which a motor terminal voltage is zero), performs such control that the phase of a resultant voltage vector of a d-axis voltage vector and a q-axis voltage vector of the permanent magnet synchronous motor varies depending on pulsation.

Claims

1-10. -10. (canceled)

11. A power converter comprising:

an inverter circuit configured to convert, by switching, a direct current link voltage having a pulsating component to an alternating current output having a predetermined frequency and a predetermined voltage to output the alternating current output to a permanent magnet synchronous motor; and

a controller configured to

control the inverter circuit by vector control for combining fundamental voltage vectors to control the switching, and

in a control state in which the fundamental voltage vectors do not include a zero vector which is a voltage vector for which a motor terminal voltage is zero, perform such control that a phase of a resultant voltage vector from a q-axis varies depending on the pulsating component, the resultant voltage vector being a resultant voltage vector of a d-axis voltage vector and a q-axis voltage vector of the permanent magnet synchronous motor.

12. The power converter of claim 11, wherein

the controller adjusts a phase of a wave with the varying phase of the resultant voltage vector from the q-axis depending on one or both of a reference correlating a torque of the permanent magnet synchronous motor and a rotational speed of the permanent magnet synchronous motor.

13. The power converter of claim 11, wherein

the controller controls the inverter circuit to output a three-phase alternating current whose continuous conduction interval corresponds to a phase of 180 degrees.

14. The power converter of claim 11, wherein

when the controller controls the inverter circuit to output a phase voltage whose conduction interval corresponds to a phase of 180 degrees, the controller controls the inverter circuit to output a pulse voltage with a carrier cycle to reduce or prevent a voltage error occurring at phase voltage switching timing every 180 degrees of the phase.

15. The power converter of claim 11, wherein

the controller changes a phase of a fundamental wave component such that an effective value for output current of the inverter circuit decreases.

16. The power converter of claim 11, wherein

the controller changes a phase of a fundamental wave component such that an effective value for fundamental wave component of an output current of the inverter circuit decreases.

17. The power converter of claim 11, wherein

the controller changes a phase of a fundamental wave component such that a peak value for output current of the inverter circuit decreases.

18. The power converter of claim 11, wherein

the controller changes a phase of a fundamental wave component such that a change in obtained torque of the permanent magnet synchronous motor decreases.

19. The power converter of claim 11, wherein

the controller changes a phase of a fundamental wave component such that a power factor of the permanent magnet synchronous motor is improved.

20. The power converter of claim 11, further comprising:

a direct current supply configured to convert an input alternating current to a pulsating direct current to supply the direct current to the inverter circuit,

wherein the controller changes a phase of a fundamental wave component such that an amplitude of a harmonic of the current input to the direct current supply decreases.

21. The power converter of claim 12, wherein

the controller controls the inverter circuit to output a three-phase alternating current whose continuous conduction interval corresponds to a phase of 180 degrees.

22. The power converter of claim 12, wherein

the controller changes a phase of a fundamental wave component such that an effective value for output current of the inverter circuit decreases.

23. The power converter of claim 21, wherein

the controller changes a phase of a fundamental wave component such that an effective value for output current of the inverter circuit decreases.

24. The power converter of claim 13, wherein

the controller changes a phase of a fundamental wave component such that an effective value for output current of the inverter circuit decreases.

25. The power converter of claim 14, wherein

the controller changes a phase of a fundamental wave component such that an effective value for output current of the inverter circuit decreases.

26. The power converter of claim 12, wherein

the controller changes a phase of a fundamental wave component such that an effective value for fundamental wave component of an output current of the inverter circuit decreases.

27. The power converter of claim 21, wherein

the controller changes a phase of a fundamental wave component such that an effective value for fundamental wave component of an output current of the inverter circuit decreases.

28. The power converter of claim 13, wherein

the controller changes a phase of a fundamental wave component such that an effective value for fundamental wave component of an output current of the inverter circuit decreases.

29. The power converter of claim 14, wherein

the controller changes a phase of a fundamental wave component such that an effective value for fundamental wave component of an output current of the inverter circuit decreases.

30. The power converter of claim 12, wherein

the controller changes a phase of a fundamental wave component such that a peak value for output current of the inverter circuit decreases.