Heat pump device, heat pump system, and a control method of three-phase inverter

Patent metadata

Field	Value
Publication number	US-9651289-B2
Application number	US-201013818132-A
Country	US
Kind code	B2
Filing date	Aug 30, 2010
Priority date	Aug 30, 2010
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

An adder adds a phase θplus, which is n times a size of 60 degrees, to a phase output from a phase switching unit and outputs the phase as a voltage command phase θ. A voltage generation unit generates voltage command value based on the voltage command phase output by the adder and outputs the command value. A drive-signal generation unit, based on an output from the voltage generation unit generates drive signals corresponding to respective switching elements of an inverter, and outputs respective generated drive signals to the corresponding switching elements of the inverter, and generates a high-frequency AC voltage in the inverter.

First claim

The invention claimed is:

1. A heat pump device comprising:
a compressor having a compression mechanism that compresses a refrigerant;
a motor that includes a rotor and operates the compression mechanism provided in the compressor;
an inverter that applies a voltage to the motor; and
an inverter control unit that controls the inverter, wherein
the inverter control unit includes
a phase switching unit that alternately switches between two fixed phases and respectively outputs one of the fixed phases as a fixed phase,
an addition unit that changes a value n, which is an integer equal to or larger than 0, for every predetermined time, and outputs a phase θ 3 obtained by adding a phase θplus, which is a value of n times 60 degrees that does not depend on a position of the rotor, to the fixed phase output from the phase switching unit,
a voltage generation unit that, when the compressor is stopped and when the rotor is correspondingly stopped, generates a voltage command value based on the phase θ 3 output by the addition unit and outputs the voltage command value, and
a drive-signal generation unit that, based on an output from the voltage generation unit, generates drive signals corresponding to respective switching elements of the inverter, outputs respective generated drive signals to the corresponding switching elements of the inverter, and generates a high-frequency AC voltage in the inverter.

2. The heat pump device according to claim 1 , wherein
the phase switching unit alternately switches a phase θ 1 and a phase θ 2 different from the phase θ 1 by 180 degrees and outputs the fixed phase, synchronously with a reference signal having a predetermined frequency.

3. The heat pump device according to claim 1 , wherein
the inverter is a three-phase inverter,
the drive-signal generation unit outputs a drive signal that turns on one of two switching elements in each series-connected circuit of the three-phase inverter and turns off the other, and
outputs a drive signal having a switching pattern in which one or two switching elements, among switching elements on a positive voltage side of the three-phase inverter, are turned on, in such a manner that only one pattern is output in a half-cycle period of the reference signal.

4. The heat pump device according to claim 1 , further comprising:
an amplitude output unit that outputs an amplitude A having a predetermined width, in such a manner that when the addition unit changes the value n, the amplitude A is decreased, and after the addition unit has changed the value n, the amplitude A is gradually increased to return to the original predetermined width, wherein
the voltage generation unit generates the voltage command value based on the phase θ 3 output from the addition unit and the amplitude A output from the amplitude output unit.

5. The heat pump device according to claim 1 , further comprising:
a drive circuit that drives the switching elements in the series-connected circuit of the inverter, wherein
the drive circuit includes
a negative-voltage-side drive circuit driven by a voltage of a switching power source to drive the switching element on a negative voltage side of the inverter, and
a positive-voltage-side drive circuit driven by a voltage of a capacitor charged by driving the negative-voltage-side drive circuit to drive the switching element on a positive voltage side of the inverter, and
the inverter control unit drives the negative-voltage-side drive circuit when the addition unit changes the value n and charges the capacitor with the voltage.

6. The heat pump device according to claim 1 , wherein
the voltage generation unit outputs an AC voltage command value having a frequency higher than an operating frequency at a time of a compression operation of the motor.

7. The heat pump device according to claim 1 , wherein
the phase switching unit switches the fixed phase at timings of at least any of tops and bottoms of the reference signal.

8. The heat pump device according to claim 1 , wherein
a rotor of the motor has an IPM (Interior Permanent Magnet) structure.

9. The heat pump device according to claim 1 , wherein
the inverter control unit further includes a detection unit that detects a state where an outside air temperature has risen by more than a predetermined temperature, as compared to a temperature before a predetermined time, and
when the detection unit has detected the state, the voltage generation unit outputs the voltage command value.

10. The heat pump device according to claim 1 , further comprising
a detection unit that detects that a state where a temperature of the compressor is lower than the outside air temperature continues for a predetermined time, wherein
when the detection unit has detected the state, the voltage generation unit outputs the voltage command value.

11. The heat pump device according to claim 1 , wherein
the voltage generation unit outputs the voltage command value, every time the predetermined time has passed since shutting down the compressor.

12. The heat pump device according to claim 1 , wherein
the switching elements constituting the inverter are wide gap semiconductors.

13. The heat pump device according to claim 12 , wherein
the wide gap semiconductors are made of any one of SiC, GaN, or diamond.

14. The heat pump device according to claim 1 , wherein
the switching elements constituting the inverter are MOSFETs having a super junction structure.

15. A heat pump system comprising: a heat pump device including a refrigerant circuit in which a compressor, a first heat exchanger, an expansion mechanism, and a second heat exchanger are sequentially connected by a pipe; and a fluid using device that uses a fluid heat-exchanged with a refrigerant in the first heat exchanger connected to the refrigerant circuit, wherein
the heat pump device includes
the compressor having a compression mechanism that compresses the refrigerant,
a motor that includes a rotor and operates the compression mechanism provided in the compressor,
an inverter that applies a voltage to the motor, and
an inverter control unit that controls the inverter, wherein
the inverter control unit includes
a phase switching unit that alternately switches a phase θ 1 and a phase θ 2 different from the phase θ 1 by 180 degrees and outputs the phase, synchronously with a reference signal having a predetermined frequency,
an addition unit that changes a value n, which is an integer equal to or larger than 0, for every predetermined time, and outputs a phase θ 3 obtained by adding a phase θplus, which is a value of n times 60 degrees that does not depend on a position of the rotor, to the phase output from the phase switching unit,
a voltage generation unit that, when the compressor is stopped and when the rotor is correspondingly stopped, generates a voltage command value based on the phase θ 3 output by the addition unit and outputs the voltage command value, and
a drive-signal generation unit that compares the voltage command value output from the voltage generation unit with the reference signal to generate drive signals corresponding to respective switching elements of the inverter, outputs respective generated drive signals to the corresponding switching elements of the inverter, and generates a high-frequency AC voltage in the inverter.

16. A control method for an inverter in a heat pump device that includes
a compressor having a compression mechanism for compressing a refrigerant,
a motor that includes a rotor and operates the compression mechanism provided in

Assignees

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

Inventors

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

Classifications

• F25B30/02

  of the compression type · CPC title

• H02P6/14

  Electronic commutators · CPC title

• H02P6/15

  Controlling commutation time · CPC title

• F25B49/025 Primary

  Motor control arrangements · CPC title

• H02M7/53875

  with analogue control of three-phase output · CPC title