Heat pump device, heat pump system, and method for controlling three-phase inverter

Patent metadata

Field	Value
Publication number	US-9543887-B2
Application number	US-201013876450-A
Country	US
Kind code	B2
Filing date	Oct 15, 2010
Priority date	Oct 15, 2010
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

A selection unit switches between a phase θp and a phase θn different from the phase θp substantially by 180 degrees, and outputs one of them in synchronization with a carrier signal. A voltage-command generation unit generates and outputs three-phase voltage command values Vu*, Vv* and Vw* based on the phase outputted by the selection unit. A PWM-signal generation unit generates three-phase voltage command values Vu*′, Vv*′ and Vw*′ by correcting the three-phase voltage command values Vu*, Vv* and Vw* outputted by the voltage-command generation unit according to a predetermined method, and generates six drive signals corresponding to switching elements of the inverter based on the three-phase voltage command values Vu*′, Vv*′ and Vw*′ and the carrier signal. The PWM-signal generation unit outputs the generated drive signals to the corresponding switching elements of the three-phase inverter, to cause the inverter to generate a high-frequency AC voltage.

First claim

The invention claimed is:

1. A heat pump device comprising:
a compressor that compresses a refrigerant;
a motor that actuates the compressor;
an inverter that applies a predetermined voltage to the motor; and
an inverter controller that controls the inverter, wherein
the inverter controller includes:
a phase switching unit that changes and outputs a phase of a voltage command value of the inverter in synchronization with a reference signal having a frequency higher than an operation frequency at the time of a compression operation of the motor;
an amplitude output unit that outputs an amplitude of the voltage command value;
a voltage-command generator that generates and outputs the voltage command value based on the phase outputted by the phase switching unit and the output amplitude of the amplitude output unit;
a voltage-command calculator that corrects the voltage command value so that a DC current flowing in the motor becomes substantially zero; and
a drive-signal generator that generates a drive signal of the inverter based on the output of the voltage-command calculator.

2. 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.

3. The heat pump device according to claim 1 , wherein
the phase switching unit switches between a phase θp and a phase θn different from the phase θp substantially by 180 degrees and outputs one of them, in synchronization with the reference signal.

4. The heat pump device according to claim 1 , wherein
the inverter is a three-phase inverter configured to parallel-connect three serial connection circuits for three phases,
the drive-signal generator corrects the three-phase voltage command values to generate the corrected voltage command values so that a time during which one of the switching elements on a positive voltage side of the three-phase inverter is on and the other two switching elements are off and a time during which two switching elements on the positive voltage side are on and the other one switching element is off become equal in length to each other in one cycle of the reference signal.

5. The heat pump device according to claim 1 , wherein
the inverter is a three-phase inverter configured to parallel-connect three serial connection circuits for three phases,
the drive-signal generator corrects the three-phase voltage command values to generate the corrected voltage command values so that a time during which all the switching elements on a positive voltage side of the three-phase inverter are on and a time during which all the switching elements on the positive voltage side are off become equal in length to each other in one cycle of the reference signal.

6. The heat pump device according to claim 3 , wherein
the reference signal is a signal whose top and valley can be identified,
the phase switching unit switches between the phase θp and the phase θn at timings of a top and a bottom of the reference signal, and
the voltage-command calculator corrects the three-phase voltage command values to generate the corrected voltage command values so that a time during which one of the switching elements on the positive voltage side is on and the other two switching elements are off in a period from a top to a bottom of the reference signal and a time during which two switching elements on the positive voltage side are on and the other one switching element is off in a period from a bottom to a top of the reference signal become equal in length to each other, or so that a time during which two switching elements on the positive voltage side are on and the other one switching element is off in the period from a top to a bottom of the reference signal and a time during which one of the switching elements on the positive voltage side is on and the other two switching elements are off in the period from a bottom to a top of the reference signal become equal in length to each other.

7. The heat pump device according to claim 3 , wherein
the reference signal is a signal whose top and valley can be identified,
the phase switching unit switches between the phase θp and the phase θn at timings of a top and a bottom of the reference signal, and
the voltage-command calculator corrects the three-phase voltage command values to generate the corrected voltage command values so that a time during which all the switching elements on the positive voltage side are on in a period from a top to a bottom of the reference signal and a time during which all the switching elements on the positive voltage side are off in a period from a bottom to a top of the reference signal become equal in length to each other, or so that a time during which all the switching elements on the positive voltage side are off in the period from a top to a bottom of the reference signal and a time during which all the switching elements on the positive voltage side are on in the period from a bottom to a top of the reference signal become equal in length to each other.

8. The heat pump device according to claim 3 , wherein the phase switching unit switches between the phase θp and the phase θn and outputs one of them in synchronization with the reference signal, while changing the phase θp for each predetermined time, and changing the phase θn to a phase different from the phase θp substantially by 180 degrees in accordance with the change of the phase θp.

9. The heat pump device according to claim 1 , wherein
the drive-signal generator outputs a drive signal for switching on one switching element of the two switching elements and switching off the other in each serial connection part of the three-phase inverter, and
outputs a drive signal having a switching pattern for switching on any one or two of the switching elements on the positive voltage side of the three-phase inverter, on the basis of one pattern for a half cycle of the reference signal.

10. The heat pump device according to claim 1 , wherein
the inverter controller further includes a detector that detects a state where an outside air temperature rises by a predetermined temperature or more as compared to an outside air temperature a predetermined time prior thereto, and
the voltage-command generator outputs a voltage command value when the detector detects the state.

11. The heat pump device according to claim 1 , wherein
the inverter controller further includes a detector that detects that a state where the temperature of the compressor is lower than an outside air temperature has continued for a predetermined time, and
the voltage-command generator outputs a voltage command value when the detector detects the state.

12. The heat pump device according to claim 1 , wherein the voltage-command generator outputs a voltage command value every time a predetermined time has passed since shutdown of the compressor.

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

14. A heat pump system comprising:
a heat pump device including a refrigerant circuit in which a compressor 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 compres

Assignees

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

Inventors

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

Classifications

• Y02B30/741

  Cross-Sectional Technologies · mapped topic

• F25B2600/021

  Inverters therefor · CPC title

• F25B49/025

  Motor control arrangements · CPC title

• H02M7/53875

  with analogue control of three-phase output · CPC title

• F04B39/06

  Cooling; Heating; Prevention of freezing · CPC title