Heat pump device, heat pump system, and method for controlling inverter

Patent metadata

Field	Value
Publication number	US-9829226-B2
Application number	US-201113993384-A
Country	US
Kind code	B2
Filing date	Apr 28, 2011
Priority date	Apr 28, 2011
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

An object of the present invention is to maintain a heating amount constant when a compressor is heated at the time of shutdown of the compressor, regardless of the influences of production tolerance and environment variations. An inverter control unit causes an inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to a motor is zero between a section in which the voltage is positive and a section in which the voltage is negative. At this time, the inverter control unit detects a value of a current flowing to the inverter in a detection section residing from immediately before a start of the de-energized section to immediately after an end of the de-energized section, and causes the inverter to generate a high-frequency AC voltage adjusted according to the detected current value.

First claim

The invention claimed is:

1. A heat pump device comprising:
a compressor having a compression mechanism for compressing a refrigerant;
a motor that actuates the compression mechanism provided in the compressor;
an inverter that applies a predetermined voltage to the motor; and
an inverter controller electrically connected to the inverter, which causes the inverter to generate a high-frequency AC voltage having a de-energized section in which the voltage applied from the inverter to the motor is zero between a section in which the voltage is positive and a section in which the voltage is negative, wherein
the inverter controller includes:
a current-value detection unit that detects a value of a current flowing to the inverter; and
a high-frequency-voltage generation unit that causes the inverter to generate a high-frequency AC voltage according to a current value detected by the current-value detection unit.

2. The heat pump device according to claim 1 , wherein the current-value detection unit detects a current flowing from the inverter to the motor in the detection section.

3. The heat pump device according to claim 1 , wherein the current-value detection unit detects a DC current flowing to the inverter at at least any one of timing immediately before the start of the de-energized section and timing immediately after the end of the de-energized section, of the detection section.

4. The heat pump device according to claim 1 , wherein
the inverter has a serial connection part in which two switching elements are serially connected, and
the current-value detection unit detects a current flowing to the serial connection part of the inverter, at at least any one of timing immediately after the end of the de-energized section and timing from immediately before the start of the de-energized section until the end of the de-energized section, of the detection section.

5. The heat pump device according to claim 4 , wherein the current-value detection unit detects a current flowing to a portion on a negative voltage side of the switching element on the negative voltage side, of the two switching elements in the serial connection part.

6. The heat pump device according to claim 1 , wherein
the inverter is a three-phase inverter configured to parallely connect three serial connection parts each having two switching elements, and
the de-energized section is a section in which, of switching elements on a positive voltage side and switching elements on the negative voltage side of the three-phase inverter, all the switching elements on one side are on and all the switching elements on the other side are off.

7. The heat pump device according to claim 1 , wherein the high-frequency-voltage generation unit causes the inverter to generate a high-frequency AC voltage with an amplitude being adjusted so that the current value becomes a predetermined value.

8. The heat pump device according to claim 1 , wherein the high-frequency-voltage generation unit causes the inverter to generate a high-frequency AC voltage adjusted to have an energization phase of the high-frequency AC voltage to the motor in which the current value is the largest, of a plurality of energization phases that are set beforehand.

9. The heat pump device according to claim 1 , wherein
the current-value detection unit detects a positive current value when the current value is positive and a negative current value when the current value is negative, at a predetermined timing, and
the high-frequency-voltage generation unit causes the inverter to generate a high-frequency AC voltage adjusted so that a mean value of the positive current value and the negative current value approaches zero.

10. The heat pump device according to claim 1 , wherein the inverter controller further includes a determination unit that estimates a winding temperature of the motor based on the current value, and when the estimated winding temperature is higher than a predetermined temperature threshold, stops the high-frequency-voltage generation unit from causing the inverter to generate a high-frequency AC voltage.

11. The heat pump device according to claim 1 , wherein the inverter is constructed of a switching element that is formed from a wide bandgap semiconductor or a MOSFET having a super junction structure.

12. A heat pump system comprising:
a heat pump device including a refrigerant circuit in which a compressor having a compression mechanism that compresses a refrigerant, a first heat exchanger, an expansion mechanism, and a second heat exchanger are sequentially connected by piping; and a fluid utilization device that utilizes fluid heat-exchanged with the refrigerant by the first heat exchanger connected to the refrigerant circuit, wherein
the heat pump device further includes:
a motor that actuates the compression mechanism provided in the compressor;
an inverter that applies a predetermined voltage to the motor; and
an inverter controller electrically connected to the inverter, which causes the inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to the motor is zero between a positive section in which the voltage is positive and a negative section in which the voltage is negative, and

the inverter controller includes:
a current-value detection unit that detects a value of a current flowing to the inverter; and
a high-frequency-voltage generation unit that causes the inverter to generate a high-frequency AC voltage according to a current value detected by the current-value detection unit.

13. A method for controlling an inverter in a heat pump device including:
a compressor having a compression mechanism that compresses a refrigerant;
a motor that actuates the compression mechanism provided in the compressor; and
an inverter that applies a predetermined voltage to the motor,
the method comprising:
a high-frequency-voltage generating step of causing the inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to the motor is zero, between a positive section in which the voltage is positive and a negative section in which the voltage is negative; and
a current-value detecting step of detecting a value of a current flowing to the inverter,

wherein at the high-frequency-voltage generating step, the inverter is caused to generate a high-frequency AC voltage according to a current value detected by the current-value detecting step.

14. The heat pump device according to claim 1 , wherein
the inverter is configured based on a serial connection circuit having two switching elements provided on a positive voltage side and a negative voltage side, respectively.

15. The heat pump device according to claim 1 , wherein
the current-value detection unit detects a value of a current flowing to the inverter in a detection section from immediately before a start of the de-energized section to immediately after an end of the de-energized section.

Assignees

• Hatakeyama Kazunori
• Shimomugi Takuya
• Matsushita Shinya
• Kusube Shinsaku
• Makino Tsutomu
• Mitsubishi Electric Corp

Inventors

• Hatakeyama Kazunori
• Shimomugi Takuya
• Matsushita Shinya
• Kusube Shinsaku
• Makino Tsutomu

Classifications

• F25B2700/151

  of the compressor motor · CPC title

• F25B49/025

  Motor control arrangements · CPC title

• F25B2400/13

  Economisers · CPC title

• F25B2600/021

  Inverters therefor · CPC title

• H02M7/53875 Primary

  with analogue control of three-phase output · CPC title