Power conversion device, motor driving device including power conversion device, blower and compressor including motor driving device, and air conditioner, refrigerator, and freezer including blower and compressor

Patent metadata

Field	Value
Publication number	US-9780717-B2
Application number	US-201315027735-A
Country	US
Kind code	B2
Filing date	Dec 3, 2013
Priority date	Dec 3, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A power conversion device includes an inverter configured by arms including phase upper-arm switching elements and phase lower-arm switching elements, a power-supply shunt resistor, lower-arm shunt resistors, and a control unit that generates drive signals corresponding to the phase upper-arm switching elements and the phase lower-arm switching elements from detection values of the voltage detectors. The power conversion device changes a ratio of time in which all of the upper-arm switching elements are in an ON state and time in which all of the lower-arm switching elements are in the ON state in one cycle of switching of the inverter according to a modulation ratio.

First claim

The invention claimed is:

1. A power conversion device that converts DC power supplied from a DC power supply into AC power, the power conversion device comprising:
an inverter configured by connecting, in parallel, arms including phase upper-arm switching elements and phase lower-arm switching elements;
a power-supply shunt resistor provided between a negative voltage side of the DC power supply and the inverter;
lower-arm shunt resistors respectively provided between the phase lower-arm switching elements for at least two phases and the power-supply shunt resistor;
a voltage detector that detects voltages between connection points of the phase lower-arm switching elements and the lower-arm shunt resistors and the negative voltage side of the DC power supply; and
a control unit that generates drive signals corresponding to the phase upper-arm switching elements and the phase lower-arm switching elements from detection values of the voltage detector, wherein
the power conversion device changes a ratio of time in which all of the upper-arm switching elements are in an ON state and time in which all of the lower-arm switching elements are in the ON state in one cycle of switching of the inverter according to a modulation ratio.

2. The power conversion device according to claim 1 , wherein the power conversion device changes the ratio to set the time in which all of the lower-arm switching elements are in the ON state to be longer than the time in which all of the upper-arm switching elements are in the ON state in one cycle of the switching of the inverter.

3. The power conversion device according to claim 1 , wherein the power conversion device changes the ratio to set the time in which all of the upper-arm switching elements are in the ON state in one cycle of the switching of the inverter to zero.

4. The power conversion device according to claim 1 , wherein the power conversion device changes the ratio according to an operation state of the inverter.

5. The power conversion device according to claim 1 , wherein the operation state is a modulation rate of the inverter.

6. The power conversion device according to claim 1 , wherein the power conversion device selects the ratio according to the modulation ratio on the basis of a table associated with the modulation ratio.

7. The power conversion device according to claim 1 , wherein the control unit calculates, from the detection values of the voltage detector, phase currents flowing to a load device and generates the drive signals on the basis of the phase currents.

8. The power conversion device according to claim 1 , wherein the control unit sets, as a detection period for the detection values of the voltage detector, a period in which at least one of the phase lower-arm switching elements is in an ON state.

9. The power conversion device according to claim 1 , wherein a wide-band gap semiconductor element is used in at least one of the upper-arm switching elements and the lower-arm switching elements.

10. A motor driving device comprising the power conversion device according to claim 1 .

11. A blower comprising the motor driving device according to claim 10 .

12. An air conditioner comprising the blower according to claim 11 .

13. A refrigerator comprising the blower according to claim 11 .

14. A freezer comprising the blower according to claim 11 .

15. A compressor comprising the motor driving device according to claim 10 .

16. An air conditioner comprising the compressor according to claim 15 .

17. A refrigerator comprising the compressor according to claim 15 .

18. A freezer comprising the compressor according to claim 15 .

Assignees

• Mitsubishi Electric Corp

Inventors

• Uemura Keisuke
• Shimomugi Takuya
• Arisawa Koichi
• Shinomoto Yosuke
• Umehara Shigeo
• Ura Shinichiro
• Tanikawa Makoto

Classifications

• F24F1/0018

  characterised by fans (with secondary air induced by injector action of the primary air F24F1/01) · CPC title

• H02M7/537

  using semiconductor devices only, e.g. single switched pulse inverters · CPC title

• F24F7/007

  with forced flow (using ducting systems F24F7/06) · CPC title

• F24F7/06

  with forced air circulation, e.g. by fan {positioning of a ventilator in or against a conduit} · CPC title

• H02M2001/0009

  Electricity · mapped topic