JPS6191445A - Compressor drive device of air conditioner - Google Patents

Abstract

PURPOSE:To heat the compressor itself from the inside thereof so that the inside temperature of the compressor is prevented from lowering less than a predetermined value, by generating an AC voltage having a frequency higher than the ordinary operation frequency by power converting means in a case where, at the low temperature time, changeover means is set is at an ON state. CONSTITUTION:An operation instructing device 22 outputs a target operation rotational speed signal, and an inverter drive signal generator 21 outputs a base drive signal to transistor 2-7 via driver circuits 15-20, and a three-phase AC voltage is applied between respective terminals of a stator winding 14, and the compressor is operated at a predetermined rotational speed. While the compressor is in stop, when the atmospheric pressure is lowered, it is detected by a temperature detector 23. Further, when the changeover device 24 is set in an ON state, a stand-by operation instruction is outputted by the operation instructing device 22, and an inverter drive signal generator 21 outputs a base drive signal to transistors 2-7 via driver circuits 15-20, and an AC voltage is applied between respective terminals of the stator winding 14. The frequency of the AC power source upon this occasion is higher than the ordinary operation frequency and uses a single-phase AC power source of approximately 25kHz.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a compressor O drive device in an air conditioner, in which heating start-up time 'fFJ) particularly at low temperatures is determined.
, intoxication, and the protection of compressors.

Disadvantages of the +1°ζ configuration of the conventional example As is generally known, when an air conditioner is operated for heating at low temperatures, the refrigerant dissolves into the lubricating oil in the compressor, causing the compressor to Even if the refrigerant circulation amount is increased, the amount of refrigerant circulated does not increase easily, and the start-up time of heating becomes longer.Furthermore, the lubricating action is inhibited, which may have an adverse effect on the valves and the like that control the flow of the refrigerant.

For this reason, in the past, the only way to avoid the above problems was to use pressure! ? 3
A separate heater was installed near the machine, and when the temperature was low, this heater was energized to heat the compressor from the outside and control the internal temperature of the compressor so that it did not fall below a certain value.

As described above, conventional compressors require a separate heater to cope with low temperatures, and furthermore, the compressor is heated from the outside, which has the disadvantage of poor efficiency and large input.

OBJECT OF THE INVENTION An object of the present invention is to provide a compressor drive device for an air conditioner driven by an inverter that efficiently heats the compressor itself from within at low temperatures without providing any special heating means. .

In order to achieve the above object, the present invention provides a means for generating a direct current voltage, a power supply converting means for converting the direct current voltage into a variable voltage and variable frequency alternating current power supply, and an alternating current power source driven by the , a compression means for circulating the refrigerant of the air conditioner, and a means for detecting the ambient temperature of the air conditioner;
It consists of a switching means that can be set to 0T manually or off at will,
When the temperature is low and the switching means is set to the ON state, the power converting means generates an AC current with a frequency higher than the normal operating frequency, heats the compressor itself from within, and lowers the internal temperature of the compressor. This is to prevent the value from falling below a certain value.

Description of examples An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is a DC power supply, 2.3.4 is a transistor whose core is connected to the positive terminal of DC power supply 1, and 5.6.7 is a transistor whose emitter is connected to the negative terminal of DC power supply 1. The connected transistors each constitute an a-phase bridge. 89.10, 11.1, and 2.13 are flywheel diodes, which are connected to the transistors 2 to 2, respectively.
7 is connected in parallel. 14 is a stator winding of a three-phase motor that drives an air-conditioning compressor; 15.16.
17.18.19.7!0 are transistors 2.3.
4.5.6.7 driver circuit, 21 is an inverter drive signal generator, 22 is an operation command device, 23 is a thermistor installed near the air conditioner (not shown),
This is a temperature detection device such as a bimetal switch, and a switching device that allows the user to turn on and off at will.

The normal driving pattern is as follows. First, the operation command device 22 outputs a target operating rotation speed signal according to the air conditioning load, and the inverter jUK #J signal generator 21
outputs a base drive signal to the transistors 2 to 7 via driver circuits 15 to 2o so that the compressor is operated at the target rotation speed.

This drive signal is shown in FIG. In the figure, UH represents the ○N10FF state of the transistor 15, and similarly, vHlWHlULlv.

WL represents the 0N10FF state of transistors 16, 17, 18, 1920, respectively, and the time T1 is about 7-33 m
It is 5ec. And H level is ONN state level is O
Indicates FF state.

As a result, when such a drive signal is applied, three current AC voltages as shown in FIG. drive with Since this control technique itself is well known, detailed explanation will be omitted.

On the other hand, if the compressor is stopped and the ambient temperature drops,
When the temperature detection device 23 detects a low temperature state and the switching device 24 is set to the on state, the operation command device 22 outputs a standby operation command, and the inverter 1
．． The drive signal generator 21 outputs base drive signals to the transistors 2 to 7 via the driver circuits 15 to 20.

This ml (fortune-telling is shown in Figure 3. In the same figure,
UH represents the 0N10FF state of the transistor 15, and similarly, V H, W HlU L, VLW
L is 0 of transistor 16, 17, 18, 1920 respectively
Indicates N10FF state, time T2 is approximately 10 μsec
One hour T3 is approximately 40 μsec. The H level represents an ON state, and the L level represents an OFF state.

As a result, when such a drive signal is applied, an alternating current voltage as shown in FIG. 3 is applied between each terminal of the stator winding 14. What requires attention here is the selection of the frequency of the AC power supply at this time. If a frequency failure below a certain level is selected, vibrations and noise will be generated, or the input will be larger than necessary, leading to an excessive temperature rise, and in some cases, problems such as the compressor starting to rotate will occur.

In this embodiment, in order to overcome the above-mentioned problems, as shown in Fig. 3, the same wave 1 (approximately 30 to 150 Hz) is
We use an AC power supply with a voltage of about 25 -m, which has a much higher frequency than normal waves.At such high and N waves, no noise is generated as they are out of the 11i range, and also due to the resonant wave number of the compressor. Since the gap is large, vibration generation can also be suppressed.

Furthermore, due to the influence of the inductance of the stator winding 14, the motor current flowing through the stator winding 14 becomes smaller, and as a result, the input power is also kept low, and the excessive temperature J:
Ga.

In addition to being rainproof, the rotating part of the pressure rock does not rotate.The reason why we adopted a single-phase AC power supply is that the device can be easily rotated in one direction, and the input power can be reduced. It is.

Furthermore, the reason for providing the switching device 24 is to allow the user to use this standby function as needed, and to avoid unnecessary power consumption when the air conditioner is not operated for a long period of time. It is something to hold down.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention provides a configuration in which a compressor in an air conditioner is driven by an inverter device at a variable voltage and a variable frequency AC power source. It supplies AC power with a higher solid wave frequency than the normal operating frequency from a commercial AC power source, and it does not require any special heating means, generates no vibration noise, and rotates the rotating part of the compressor. It is possible to heat the compressor from inside without heating and increase the heat insulation effect of the compressor with small electric power.With one simple F, it shortens the warm-up time at low temperatures and improves the lubrication inside the compressor. This has the effect of smoothing the action and protecting the valve, etc.

[Brief explanation of drawings]

Fig. 1 is a schematic circuit diagram of a driving device for a compressor in an air conditioner showing an embodiment of the present invention, and Fig. 2 shows the conduction state of transistors, etc. during normal operation in the same driving device, and the voltage applied to the motor. A time chart showing waveforms. FIG. 3 is a time chart showing the transistor conduction state at low temperature in the drive device and the voltage waveform applied to the motor. 1...DC power supply, 2-7...Transistor, 8-1
3...Diode, 14...Stator winding (compressor), 21...Impact drive UJ signal generator 1, 23...Temperature detection device, 24... ...Switching device. Name of agent: Patent attorney Kazuo Nakao and 1 other person 2nd
Figure 3

Claims (1)

[Claims] means for generating a direct current voltage, a power supply converting means for converting the direct current voltage into a variable voltage and variable frequency alternating current power supply, a compression means driven by the alternating current power supply and circulating a refrigerant for the air conditioner, and the air conditioner. It is composed of a temperature detection means for detecting the ambient temperature of the machine, and a switching means that can be set to be turned on or off at will, and when the switching means is set to the on state and the temperature detection means detects a low temperature state. When I did,
A compressor drive device for an air conditioner that supplies an AC voltage of a higher frequency to the compression means than during normal operation.