JPH09113039A - Heater device for compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat a compressor and eliminate a useless consumption of electrical power only when refrigerant is being liquified by a method wherein a state of refrigerant is estimated in response to a discharging temperature and a discharging pressure of a compressor, a chopping wave-form is outputted in response to the estimated output and an output of a frequency instruction part of the compressor so as to drive the compressor. SOLUTION: Each of an output of a discharging pipe temperature sensor 11 for use in sensing a discharging temperature of a compressor 1 and an output of a pressure sensor 12 for use in sensing a discharging pipe pressure is inputted to a refrigerant state estimating means 13. The refrigerant stateestimating means 13 outputs ON indicating that the refrigerant is liquified in the case that the discharging pipe pressure is A1 and a discharging pipe temperature T1 at that time is lower than a saturation temperature Tα of the refrigerant. If the temperature is lower than the saturation temperature Tα, it may output ON indicating that the refrigerant is liquified. In addition, if the temperature is higher than the saturation temperature Tα, it is estimated that all the refrigerants are in gas state so as to output OFF. A control circuit 6 has as its input, an ON output fed from the refrigerant state estimating means 13 and an output of the frequency instruction part 14 for outputting a frequency driving the compressor 1, outputs a chopping wave-form to a frequency variable setting device 5 so as to heat the compressor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner provided with means for freely changing the rotation of a compressor, and more particularly to a heating device for the compressor.

[0002]

2. Description of the Related Art Generally, when the ambient temperature is low in a compressor, in order to prevent the compressor from being damaged due to the liquid compression state, the compressor is preheated so that liquid compression does not occur at the time of starting the compressor. For example, the one described in JP-A-61-14487 is known. FIG. 6 shows the structure of a conventional compressor heating device. The compressor 1 is a three-phase motor unit 1.
It is composed of a and a compressor section 1b, and the indoor heat exchanger 2, the decompression device 3, and the outdoor heat exchanger 4 are sequentially connected by piping. The output from the frequency converter 5 is supplied to the three-phase electric motor unit 1a, and it is driven at a variable speed. The frequency converter 5 is controlled by the control circuit 6. The control circuit 6 receives the room temperature signal from the room temperature detector 7 and the set temperature signal of the operation unit 8.

The operation of the compressor heating apparatus having the above-described structure will be described below. When the compressor 1 is heated, a heating signal is sent from the control circuit 6 to the frequency converter 5. The frequency converter 5 gives an output to only two phases among three-phase outputs by this heating signal.

As shown in FIG. 7, only two of the three phases U, V and W are energized. And energization period (t _{ON in the} figure)
Inside is properly chopped to adjust the current so that the winding does not burn out. This intermittent energization heats the windings and heats the compressor 1.

In this way, the compressor 1
By energizing only the phases, the compressor 1 can generate heat without rotating.

[0006]

However, the above-mentioned conventional configuration has a problem that the compressor 1 is heated even when the refrigerant is vaporized in the compressor 1, so that unnecessary power is consumed.

The present invention solves the conventional problems, and an object thereof is to realize an efficient compressor heating device, which can heat the compressor 1 only when the refrigerant is liquefied.

[0008]

According to the present invention, a compressor, a temperature detector for detecting the discharge temperature of the compressor, a pressure detector for detecting the discharge pressure, and an output of the temperature detector and the pressure detector are used. Refrigerant state estimating means for estimating the state of the refrigerant, a frequency command section for instructing the drive frequency of the compressor, a control circuit for outputting a chopping waveform by the output of the frequency command section and the output of the refrigerant state estimating means, and the control circuit It is composed of a frequency variable device which drives the compressor by the output.

Thus, by estimating the state of the refrigerant from the temperature and pressure of the compressor discharge pipe, the compressor can be heated only when necessary.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is a compressor, a temperature detector for detecting the discharge temperature of the compressor, a pressure detector for detecting the discharge pressure, and the discharge pressure. Refrigerant state estimating means for estimating the state of the refrigerant from a signal from a temperature detector and the output of the temperature detector, a frequency command section for instructing a drive frequency of the compressor, an output of the frequency command section and the refrigerant state estimation. A control circuit that outputs a chopping waveform by the output of the means, and is composed of a frequency variator that drives the compressor by the output of the control circuit, the state of the refrigerant is estimated from the temperature and pressure of the refrigerant,
By heating the compressor only when the refrigerant is liquefied and not heating it when the refrigerant is vaporized, the compressor can be efficiently heated.

According to a second aspect of the present invention, a compressor, a temperature detector for detecting a discharge temperature of the compressor, a discharge temperature comparing means for comparing an output of the discharge temperature with a certain value, and the compressor. , A control circuit for outputting a chopping waveform from the output of the frequency command section and the output of the discharge temperature comparison means, and a frequency variator for driving the compressor by the output of the control circuit. According to the first aspect of the invention, the accuracy is worse, but there is an effect that there is a cost merit.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. The same components as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

(Embodiment 1) FIG. 1 is a schematic configuration diagram showing the configuration of the present invention, FIG. 2 is a chopping waveform generation flowchart of the control circuit 6, and FIG. 3 is a graph of saturation temperature characteristics with respect to refrigerant pressure. Reference numeral 11 is a discharge pipe temperature detector that detects the discharge pipe temperature of the compressor 1, and 12 is a pressure detector that detects the discharge pipe pressure. The outputs of the temperature detector 11 and the pressure detector 12 are connected to the refrigerant state estimating means 13, respectively.

From FIG. 3, the refrigerant state estimating means 13 judges that the output T1 of the temperature detector 11 is lower than the saturation temperature Tα of the refrigerant when the output A1 of the pressure detector 12 is liquefied. Outputs ON. If it is higher than the saturation temperature Tα, it is estimated that the refrigerant exists only as a gas, and OFF is output.

The frequency command unit 14 outputs a frequency for driving the compressor 1. The control circuit 6 uses the refrigerant state estimating means 13
And the output of the frequency command unit 14 are input to the frequency variator 5.

The operation of the heating device for the compressor configured as described above will be described with reference to FIG.

In FIG. 2, first, in step 1, the control circuit 6 determines whether the signal from the frequency command unit 14 is 0 Hz. If it is not 0 Hz, the process proceeds to step 2 and 0H.
If z, go to step 3.

At step 2, the control circuit 6 outputs a chopping waveform for normal operation. Control circuit 6 at step 3
Determines whether the output of the refrigerant state estimating means 13 is ON or OFF. If the output of the refrigerant state estimating means 13 is ON, the process proceeds to step 4, and if not, the process proceeds to step 5.

At step 4, the control circuit 6 outputs the chopping waveform of FIG. 7 to the frequency variable device 5.

At step 5, the chopping waveform is not output to the frequency variable device 5. Although the temperature detector 11 and the pressure detector 12 are set to the temperature and pressure of the discharge pipe of the compressor 1 in the above description, the same applies to the temperature and pressure of the suction pipe of the compressor 1.

(Embodiment 2) FIG. 4 is a schematic configuration diagram of a compressor heating apparatus in the second embodiment, and FIG. 5 is a control circuit 6
3 is a chopping waveform generation flowchart of FIG.

In FIG. 4, reference numeral 15 is a temperature comparing means, which is turned on when the output of the temperature detector 11 is lower than the reference temperature.
Is output, and if it is higher than the reference temperature, OFF is output.

In FIG. 5, in step 1, the control circuit 6
Determines whether the signal from the frequency command unit 14 is 0 Hz, and if not 0 Hz, proceeds to step 2, and if 0 Hz, proceeds to step 3.

At step 2, the control circuit 6 outputs a chopping waveform for normal operation. Control circuit 6 at step 3
Determines whether the output of the temperature comparison means 15 is ON or OFF. If the output of the temperature comparison means 15 is ON, step
4. If it is OFF, proceed to step 5.

At step 4, the control circuit 6 outputs the chopping waveform of FIG. 7 to the frequency variable device 5.

At step 5, the chopping waveform is not output to the frequency variable device 5. In the above description, the temperature detector 11 is set to the temperature of the discharge pipe of the compressor 1.
The same applies to the temperature of the suction pipe.

[0027]

As described above, according to the present invention, since the heating is performed only when it is necessary to heat the compressor, it is possible to efficiently heat the compressor.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a heating device for a compressor according to a first embodiment of the present invention.

FIG. 2 is a chopping waveform generation flowchart of the control circuit 6 according to the first embodiment of the present invention.

FIG. 3 is a diagram showing saturation temperature characteristics with respect to refrigerant pressure.

FIG. 4 is a schematic configuration diagram of a compressor heating device according to a second embodiment of the present invention.

FIG. 5 is a chopping waveform generation flowchart of the control circuit 6 according to the second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a conventional compressor heating device.

FIG. 7 is a conventional chopping waveform generation pattern diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 5 Frequency variable device 6 Control circuit 11 Temperature detector 12 Pressure detector 13 Refrigerant state estimation means 14 Frequency command part 15 Temperature comparison means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Izumi ▼ Izumi Tadashi 4-5 Takaida Hondori, Higashi-Osaka City, Osaka Prefecture Matsushita Refrigerator Co., Ltd. (72) Inventor Yoshiro Tsuchiyama 1006 Kadoma, Kadoma, Osaka Prefecture Address Matsushita Electric Industrial Co., Ltd. (72) Inventor Keizo Matsui 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshiteru Ito 1006 Kadoma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. 72) Inventor, Tsutsuharu Yoshioka, 1006 Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A compressor, a temperature detector for detecting a discharge temperature of the compressor, and a pressure detector for detecting a discharge pressure,
Refrigerant state estimating means for estimating the state of the refrigerant from the outputs of the temperature detector and the pressure detector, a frequency command section for instructing a drive frequency of the compressor, an output of the frequency command section and the refrigerant state estimating means. A heating device for a compressor, which comprises a control circuit that outputs a chopping waveform according to the output of 1. and a frequency changer that drives the compressor according to the output of the control circuit. 2. A compressor, a temperature detector for detecting a discharge temperature of the compressor, a discharge temperature comparing means for comparing an output of the discharge temperature with a certain value, and a frequency for instructing a drive frequency of the compressor. A compressor comprising a command unit, a control circuit that outputs a chopping waveform from the output of the frequency command unit and the output of the discharge temperature comparison unit, and a frequency variator that drives the compressor according to the output of the control circuit. Heating device.