JPS6229867A - Refrigeration cycle device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a refrigeration cycle apparatus having variable capacity compression.

[Technical background of the invention and its problems]

In general, an air conditioner equipped with a heat pump refrigeration cycle that sequentially connects a variable capacity (variable rotation speed) compressor, a four-way valve, an outdoor heat exchanger, a pressure reduction device, an indoor heat exchanger, etc. For example, at the start of heating operation, in order to speed up the rise of heating capacity, the operating frequency F of the compressor is reduced to the maximum operating frequency Fmax in a short period of time, as shown in Figure 6.
It is desirable to raise the temperature to .

However, simply increasing the rate of increase in the operating frequency F will cause a forming phenomenon in the lubricating oil in the compressor when the concentration of the compressor is low, and the refrigeration cycle will become unstable, causing fluid leakage to the compressor. The back is increased, and problems such as valve breakage due to liquid compression are likely to occur in the compressor. Moreover, when the forming phenomenon occurs, the lubricating oil is not distributed to the shaft and bearings of the compressor motor (insufficient oil supply), which may cause large contact wear and damage to the mechanical parts.

To prevent such problems, when starting heating operation,
As shown in the figure, there is a compressor in which the operating frequency F of the compressor is kept at a predetermined frequency for a certain period of time t during its rise. However, in this case, it takes time for the operating frequency F to reach the maximum operating frequency Fmax, resulting in a delay in the rise of the heating capacity.

[Purpose of the invention]

This invention was made in view of the above circumstances,
The purpose is to provide a highly reliable refrigeration cycle device that can quickly ramp up capacity without causing liquid compression or oil supply shortages in the compressor at the start of operation.

[Requirements for invention]

According to the present invention, at the start of operation, the rate of increase in the operating frequency of the variable capacity compressor is variably controlled depending on the situation.

[Embodiments of the invention]

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

As shown in FIG. 2, a variable capacity compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a pressure reducing device such as an expansion valve 4, and an indoor heat exchanger 5 are connected in sequence, and a bomb type refrigeration circuit is constructed. It is configured.

That is, during cooling operation, the refrigerant flows in the direction of the solid arrow shown in the figure (cooling cycle), and the outdoor heat exchanger 3 acts as a condenser, and the indoor heat exchanger 5 acts as an evaporator. In addition, during single-cell operation, the four-way valve 2 switches to cause the refrigerant to flow in the direction of the dashed arrow in the figure (@cell), and the outdoor heat exchanger 3 acts as an evaporator.
Indoor heat exchanger 5 acts as a condenser.

An outdoor fan 6 is provided near the outdoor heat exchanger 3, and an indoor fan 7 is provided near the indoor heat exchanger 5. Further, a case temperature sensor (thermistor) 8 is attached to the pressure mfM1 to detect the case temperature of the pressure 41.

FIG. 1 shows the control circuit.

Reference numeral 10 denotes a control section, which includes a microcomputer and its peripheral circuits. The control unit 10 includes a driving operation unit 11, an indoor temperature sensor 12, and an outside temperature sensor 13.
, the case temperature sensor 8, the city fan drive circuit 14,
A relay driver 15 and the like are connected. Here, the indoor fan drive circuit 14 drives the indoor fan motor 7M according to commands from the control section 10. The relay driver 15 drives the fan relay 16 and the four-way valve relay 17 in accordance with commands from the control unit 1o. The fan relay 16 is connected to the outdoor fan motor 6M.
It opens and closes the energizing path for the The four-way valve relay 17 opens and closes the current supply path to the four-way valve 2.

Roughly speaking, an inverter drive circuit 18 is connected to the control section 10. This inverter drive circuit 18 includes a control unit 1
The switching element of the inverter circuit 19 is turned on in response to the frequency setting command from 0.

It is driven off. The inverter circuit 19 once rectifies the output voltage of the commercial power supply #i20, converts it into AC power of a predetermined frequency (and voltage) by switching, and supplies the AC power to the compressor motor 1M.

Next, the operation of the above configuration will be explained with reference to FIG.

In the driving operation section 11, press [! Along with setting Jibo driving,
Set the desired indoor temperature Ts and turn on the operation switch. Then, the control unit 10 detects the indoor temperature Ta using the indoor temperature sensor 12, and if the indoor temperature Ta is lower than the above-mentioned indoor set temperature Ts, the control unit 10 drives the inverter circuit 19 and starts the compressor motor 1M based on its output. do.

At this startup, the control unit 10 controls the case temperature Tcp of the compressor 1 detected by the case temperature sensor 8 and the outside air temperature sensor 1.
The case temperature T is compared with the outside air temperature To detected in step 3.
If ap is higher than outside temperature To, inverter circuit 1
The output frequency, that is, the operating frequency F, is rapidly increased toward the maximum operating frequency Fmax, as shown by the solid line in FIG. Therefore, the capacity of the compressor 1 increases rapidly, and heating can be started more quickly.

In this case, since the case temperature Tcp of the pressure wA machine 1 is sufficiently high, even if the operating frequency F is suddenly increased, no forming phenomenon will occur in the lubricating oil in the compression seam 1, and the liquid back-up to the compression seam 1 will not occur. is not increased. Therefore, liquid compression does not occur in the compressor 1, and valve breakage and the like can be prevented. Moreover, since no forming phenomenon occurs, sufficient oil can be supplied to the shaft and bearings of the compressor motor 1M, and damage to the mechanical parts can be prevented.

In this way, when the startup is completed, the control unit 10 controls the indoor temperature T.
The operating frequency F is controlled according to the difference between a and the indoor set temperature TS, that is, the air conditioning load, and normal operation is performed.

On the other hand, at startup, the case temperature Tap is the outside temperature T.

If the operating frequency F is lower than the maximum operating frequency Fmax, the control unit 10 increases the protection speed toward the maximum operating frequency Fmax, as shown by the broken line in FIG. Here, the protection speed is a slow speed at which there is no risk of liquid compression or oil supply shortage occurring in the compressor 1. Therefore, although the capacity of the compressor 1 does not increase quickly, the start-up of heating is faster than in the conventional system where the increase in the operating frequency F is temporarily suppressed midway through.

In addition, in the above embodiment, compression! 11 case temperature Tcp
The rate of increase in the operating frequency F is changed according to the comparison result between the temperature and the outside air temperature TO. However, if the compressor 1 has a preheating function, the rate of increase in the operating frequency F varies depending on the presence or absence of preheating as shown in Fig. 5. The rate of increase in the operating frequency F may be changed. In other words, as a preheating means, there is a winding heating method in which a small amount of current is passed from the inverter circuit 19 to the windings of the compressor motor 1M. stores it and rapidly increases the operating frequency F upon startup. Furthermore, if preheating is not performed, the protection speed of the operating frequency F is increased upon startup.

Further, in the above embodiment, the application to an air conditioner was described, but the present invention can be similarly applied to other equipment as long as it uses a refrigeration cycle.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a highly reliable refrigeration cycle device that can quickly ramp up capacity without causing liquid compression or oil supply shortages in the compressor at the start of operation.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of a control circuit in one embodiment of the present invention, Fig. 2 is a diagram showing the configuration of a refrigeration cycle and its surroundings in the same embodiment, and Fig. 3 explains the operation of the same embodiment. FIG. 4 is a diagram for explaining the rate of increase in the operating frequency F in the same embodiment. FIG. 5 is a flow chart for explaining a modification of the same embodiment.
FIGS. 6 and 7 are diagrams for explaining the rate of increase in the operating frequency F in the prior art, respectively. DESCRIPTION OF SYMBOLS 1... Variable capacity compressor, 2... Four-way valve, 3... Seedling pot heat exchanger, 4... Expansion valve (pressure reducing device), 5... Indoor heat exchanger, 8... Case temperature sensor, 10... Control unit, 13... Outside air temperature sensor, 19... Inverter circuit.

Claims (2)

[Claims] (1) In a refrigeration cycle device comprising a refrigeration cycle in which a variable capacity compressor, a condenser, a pressure reducing device, an evaporator, etc. are connected in sequence, the operating frequency of the variable capacity compressor is controlled according to the load. A refrigeration cycle apparatus characterized by comprising means for variably controlling the rate of increase in the operating frequency of the variable capacity compressor at the time of start. (2) The refrigeration cycle apparatus according to claim 1, wherein the means variably controls the upper limit speed of the operating frequency according to a comparison result between the temperature of the variable capacity compressor and the outside air temperature. .