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Air conditioner

A technology of air conditioner and inverter, which is applied in the direction of high-efficiency regulation technology, climate sustainability, irreversible cycle compressors, etc.

Active Publication Date: 2012-05-23
MITSUBISHI ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] This phenomenon is called so-called liquefaction of the refrigerant. As a result of the liquefaction of the refrigerant, the liquid refrigerant dilutes the oil in the oil storage tank, or dissolves into the oil storage tank when the compressor is restarted. The liquid refrigerant in the oil in the oil becomes a bubble and dissolves to cause a foaming phenomenon (foaming phenomenon), or the compression element directly absorbs the liquid refrigerant to cause liquid compression, which becomes the cause of the failure of the compressor

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0028] figure 1 It is a block diagram of the air conditioner in Embodiment 1.

[0029] exist figure 1 Among them, 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is an expansion valve, and 5 is an indoor heat exchanger, and these components are installed so that the refrigerant circulates through the refrigerant pipe 8 .

[0030] Also, inside the compressor 1 are provided a compression mechanism 11 for compressing refrigerant and a motor 12 for operating it. 6 is a PWM inverter, which is electrically connected to the motor 12 and supplies voltage to the motor 12 . 7 is a control unit, which is electrically connected to the PWM inverter 6 and outputs signals for controlling the PWM inverter.

[0031] The control unit 7 is provided with: a liquefaction detection unit 74 which detects the liquefaction of the refrigerant in the compressor 1; a first PWM signal generation unit 72 which generates an inverter control signal for rotating the motor 12; and...

Embodiment approach 2

[0057] In Embodiment 1, only a high-frequency voltage is applied, and the rotor of the motor 12 is not described. However, the rotor of the motor 12 may be a magnet-embedded type.

[0058] In this case, the surface of the rotor where the high-frequency magnetic flux is interlinked also becomes a heat generating part, so the contact surface of the refrigerant increases, and rapid heating can be performed to the compression mechanism, so there is an effect that the refrigerant can be heated efficiently. On the other hand, There is a problem that liquid refrigerant cannot be heated stably due to changes in inductance due to the rotor structure of the embedded magnet type synchronous motor.

[0059] In this embodiment, a method for solving this problem is provided.

[0060] Figure 8 It is a diagram showing the rotor structure and inductance change of an embedded magnet type synchronous motor. exist Figure 8 Among them, 121 denotes an iron core, and 122 denotes a magnet. In s...

Embodiment approach 3

[0066] In the above-mentioned embodiments, the structure for obtaining the high-frequency heating effect of the motor has been described, but during high-frequency heating, there are problems that the switching loss of the inverter increases and the noise represented by the noise terminal voltage increases.

[0067] In Embodiment 3, inverter losses during high-frequency heating are reduced by using MOS-FETs instead of IGBTs that are generally used as switching elements of inverters.

[0068] Figure 10 It is a figure which shows the inverter output voltage / current waveform at the time of high-frequency heating.

[0069] The motor winding during high-frequency heating roughly becomes an inductive load, so Figure 10 As shown in , the current becomes a waveform with a phase delay of approximately 90 degrees (power factor zero) with respect to the voltage. The ratio of regeneration time is about 1 / 2, which is greatly increased than that during operation. In addition, since the...

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Abstract

Disclosed is an air conditioner wherein a liquid refrigerant can be preheated without generating vibrations or noises. The air conditioner is comprised of a refrigerant circuit obtained by sequentially connecting a compressor (1), an indoor heat exchanger (5), an expansion valve (4), and an outdoor heat exchanger (3), a motor (12) for operating a compression mechanism (11) provided within the compressor (1), an inverter (6) for driving the motor (12), and a control means (7) for controlling the inverter (6). The control means (7) is comprised of a dormant state detecting means (74) for detecting the dormant state of a refrigerant in the compressor (1), a first PWM signal generating means (72) for generating an inverter controlling signal for driving the motor (12), a second PWM signal generating means (73) for generating an inverter controlling signal for causing the motor (12) to perform a preheating operation, and a switching means (71) which switches so as to cause the first PWM signal generating means (72) or the second PWM signal generating means (73) to output a control signal to the inverter (6).

Description

technical field [0001] The present invention relates to an air conditioner using a compressor, and particularly relates to preheating of a liquid refrigerant (liquid coolant) at the start of operation. Background technique [0002] Generally, in an air conditioner in which the indoor and outdoor heat exchangers are connected to the compressor by refrigerant piping, when the operation of the compressor is stopped, the refrigerant may migrate to the coldest part of the refrigeration cycle and condense. tendency. [0003] For example, when the heating operation is stopped at night, the temperature of the compressor and the outdoor heat exchanger is lower than that of the indoor heat exchanger, so the refrigerant in the indoor heat exchanger moves to the compressor and the outdoor heat exchanger. . In addition, if the outdoor air temperature rises in the morning, the heat capacity of the outdoor heat exchanger is smaller than that of the compressor, and the temperature of the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F25B1/00
CPCF25B2500/13Y02B30/741F25B2500/26F25B49/025F25B2600/021F25B49/005F25B2400/01F25B2500/31Y02B30/70
Inventor 坂廼边和宪畠山和德松下真也楠部真作牧野勉
Owner MITSUBISHI ELECTRIC CORP