KR0127317B1 - Refrigerator flow control method and apparatus of inverter room aircondition - Google Patents

Abstract

The present invention relates to a method and apparatus for controlling a refrigerant flow rate of an inverter room air conditioner, which is configured to proportionally change a refrigerant flow rate according to a load variation and a frequency of a refrigeration cycle to maintain an optimal refrigeration cycle and high efficiency, and to control an electronic expansion valve. It is to widen to keep stable state without error. The present invention as described above is a process of obtaining a correction amount by estimating the pressure loss of the heat exchange means in accordance with the operating frequency of the control target and the current input and exit temperature obtained from the predicted correction amount and the heat exchange means and the target overheating obtained from the user Calculating the degree of opening degree of the control object for controlling the flow rate of the refrigerant by calculating the degree, and controlling the degree of opening of the control object according to the increase of the sensible degree of opening obtained above and the previous value of the opening degree. This is achieved by the process of adjusting the inflow rate.

Description

Refrigerant flow control method and device for inverter room air conditioner

1 is a configuration diagram of a refrigeration cycle of a conventional inverter room air conditioner.

2 is a refrigerant cycle diagram of the inverter room air conditioner of the present invention.

3 is a view showing in more detail the second expansion electron expansion edge.

4 is a flow characteristic curve diagram according to the application of the voltage of the second expansion electron expansion valve.

5 is a flow characteristic curve according to the number of pulses of the second expansion electron expansion valve.

6 is a diagram showing the pressure loss correction amount of the outdoor heat exchanger according to the operating frequency of FIG.

7 is a signal flow diagram for the description of FIG.

* Explanation of symbols for main parts of the drawings

200: compression means 201: four-way opening and closing member

202: first heat exchange means 203, 204: first and second temperature sensing member

205: electronic expansion member 206: micom

207: capillary 208: second heat exchange means

The present invention relates to an inverter room air conditioner, and in particular, the refrigerant flow rate is finely changed according to the set cycle temperature and the frequency change to maintain the optimum refrigeration cycle and high efficiency, as well as the control range of the electronic expansion valve regardless of the load cycle of the refrigeration cycle. The present invention relates to a method and apparatus for controlling a refrigerant flow rate of an inverter room air conditioner so as to maintain a stable state. In general, the inverter room air conditioner is composed of a compression unit, a condensation unit, and an evaporation unit to compress a refrigerant, and condensate, expand, and evaporate the compressed gaseous refrigerant into a liquid refrigerant to obtain a cooling effect of the room continuously. . Such a conventional inverter room air conditioner has a compressor 100 for compressing a refrigerant and changing the gas into a gas state of high temperature and high pressure, as shown in FIG. 1, and a gas of high temperature and high pressure compressed by the compressor 100. A condenser 101 for condensing the refrigerant in a state to a liquid state at a high temperature and a high temperature, a capillary tube 102 for converting the liquid condensed state condensed in the condenser 101 into a low temperature low pressure liquid refrigerant, and the capillary tube ( It is composed of an evaporator 103 which cools the indoor air to a low temperature and supplies the gas refrigerant to the compressor 100 again while exchanging the low temperature and low pressure liquid refrigerant with indoor air to convert it into a gas refrigerant. .

In the conventional inverter room air conditioner, the low-temperature low-pressure gas refrigerant from the compressor 100 is changed to high-temperature high-pressure, and the gaseous refrigerant supplied by the condenser 101 receives heat that is absorbed in the high-temperature, high-pressure gas refrigerant. The liquid refrigerant at room temperature and high pressure is converted into a liquid refrigerant at room temperature and high pressure, and is converted into a liquid refrigerant at low temperature and low pressure while passing through the capillary tube 102 and supplied to the evaporator 103.

The evaporator 103 changes the liquid refrigerant of low temperature and low pressure through the capillary tube 102 into a gas refrigerant while performing heat exchange with the air in the room, thereby changing the air in the room to a low temperature, and the refrigerant changed into the gas phase is again converted into a compressor ( 100), the refrigerant is compressed, condensed, expanded, and evaporated continuously and repeatedly to give a cooling effect to the room.

In the case where the inverter room air conditioner is used both indoor and outdoor, it is possible to operate the refrigerant cycle in the opposite manner to the above.

At this time, the condenser 101 is operated as an evaporator, and the evaporator 103 acts as a condenser to provide a cooling effect indoors and outdoors.

However, in such a conventional inverter room air conditioner, since a refrigeration cycle is formed without using an electronic expansion valve, there are many time delays in system stability due to frequency change and load fluctuation, and also for low speed operation and high speed operation of the compressor by frequency. Due to the large change in the refrigerant flow rate, it is difficult to maintain an optimal refrigeration cycle, and there is a problem in that an error such as a decrease in loss of the cycle mechanism is generated.

Accordingly, an object of the present invention, in view of such a conventional problem, to maintain the optimum refrigeration cycle and high efficiency by proportionally varying the refrigerant flow rate in accordance with the load variation and frequency of the refrigeration cycle, and the control range of the electronic expansion valve The present invention provides a method and apparatus for controlling a refrigerant flow rate of an inverter room air conditioner so as to maintain a stable state without error.

As a method for achieving the object of the present invention, the process of obtaining a correction amount by estimating the pressure loss of the heat exchange means according to the operating frequency of the control target, and the current inlet and outlet sides obtained from the predicted correction amount and the heat exchange means Calculating the opening degree increase of the control object controlling the flow rate of the refrigerant by calculating the target superheat degree set by the temperature and the user, and according to the increase of the current opening degree and the previous opening degree value obtained above. It is achieved by controlling the opening degree to adjust the refrigerant flow into the heat exchange means.

As another means for achieving the object of the present invention, the refrigerant obtained by the compression from the compression means to condense or evaporate to heat exchange with the outside air. An electronic expansion member installed between the inlet and outlet of the second heat exchange means to adjust the flow of the refrigerant, and a first installed at the inlet and outlet sides of the first and second heat exchange means to sense the inlet and outlet temperatures The microcomputer controls the opening degree of the electronic expansion member by calculating and processing the second temperature sensing member, the temperature detected by the first and second temperature sensing members, the operating frequency of the expansion valve, and the target superheat degree set by the user. The present invention will be described below in detail with reference to the accompanying drawings.

2 is a refrigerant cycle system diagram of the inverter room air conditioner of the present invention. As shown therein, a compression means (200) for compressing a refrigerant to change into a gaseous state of high temperature and high pressure, and a high temperature and high pressure compressed by the compression means (200) Four-way opening and closing member 201 for supplying and cutting off the gaseous refrigerant according to the cooling option of the indoor and outdoor sides, and a high-temperature, high-pressure gaseous refrigerant supplied through the four-way opening and closing member 201. Heat exchanged with the cold air of the outdoor to change the liquid state of the room temperature and high pressure while heating the outdoor air to a hot temperature and the first heat exchange means 202 is installed at the inlet side of the first heat exchange means 202 to The opening and closing degree is changed according to the first temperature sensing member 203 for sensing, the second temperature sensing member 204 installed at the outlet side of the first heat exchange means 202, and the external control signal for sensing the temperature. The first An electronic expansion member 205 for controlling and supplying a flow rate of the refrigerant in the liquid state condensed by the exchange means 202, an operating frequency of the electronic expansion member 205, and the first and second temperature sensing members 203 ( The microcomputer 206 for controlling the opening degree of the electronic expansion member 205 by calculating and processing the temperature T1 and T2 of the inlet and outlet sides detected by the 204 and the target superheat degree SHo set by the user. And a low temperature low pressure liquid refrigerant through the capillary tube 207 and the low temperature low pressure liquid refrigerant through the capillary tube 207 to convert the liquid refrigerant controlled by the electronic expansion member 205 into a low temperature low pressure liquid refrigerant. It consists of a second heat exchange means 208 for cooling the air in the room to a low temperature while converting it into a refrigerant and supplying the gas refrigerant to the compression means 200 again, wherein the first and second heat exchange means 202 ( 208 is between the refrigerant supplied from the compression means 200 Depending on the direction and operates in the heating, cooling or cooling and heating modes, and also uses the electric expansion member 205 is a stepping motor (step motor), a wide control range.

That is, the electronic expansion member 205 is a rotor 205b and a motor rotating in stages by the magnetic field of the stator coil 205a according to the control pulse output from the microcomputer 206 as shown in FIG. A step motor 205c formed of a shaft (not shown) and an inlet pipe of the first and second heat exchange means 202 and 208 fixed to the shaft of the stem motor 205c to move up and down stepwise. 205e) and a valve shaft 205d for controlling the amount of refrigerant introduced by adjusting the opening degree of the outlet pipe 205f.

FIG. 7 is a flow chart of the microcomputer control signal for the description of FIG. 2, and as shown therein, the pressure loss of the first heat exchange means 202 is estimated according to the operating frequency of the electronic expansion valve 205 and the correction amount ΔT1 is shown. The first step (ST1) to obtain the saturation temperature by subtracting the predicted correction amount (ΔT1) and the current inlet side temperature (T1) obtained from the first temperature sensing member 203 from the first heat exchange means (202) A second step ST2 for obtaining a value Te, a saturation temperature value Te obtained in the second step, and a current outlet obtained by the second temperature sensing member 204 from the first heat exchange means 202 The third step ST3 of subtracting the side temperature T2 to obtain the superheat degree SH, and the deviation (ep) between the superheat degree SH obtained in the third step and the target superheat degree SH set by the user. The opening degree increase Δp of the electronic expansion member 205 is obtained with the fourth step ST4 and the deviation ep obtained in the fourth step. The fifth step ST5, the increment of the opening degree P of the electronic expansion member 205 obtained in the fifth step Δp and the opening degree value of the previous electronic expansion member 205 are added to finally open. The sixth step (ST6) of controlling the opening degree of the electronic expansion member 205 by the precision operation amount (P ') to adjust the amount of refrigerant introduced into the first and second heat exchange means (202) (208).

If described in detail with reference to Figures 2 to 7 the effects of the present invention configured as described above.

First, the first heat exchanging means 202 is in heating mode or cooling mode, and the second heat exchanging means 208 is in accordance with the refrigerant cycle direction according to the opening / closing direction selection of the four-way opening and closing member 201. In contrast to), it operates in cooling mode or heating mode.

That is, when the four-way opening and closing member 201 supplies the high temperature and high pressure gas refrigerant compressed from the compression means 200 to the first heat exchange means 202, the first heat exchange means 202 operates in the heating mode. The second heat exchange means 208 is operated in the cooling mode, on the contrary, when the four-way opening and closing member 201 supplies the high temperature and high pressure gas refrigerant compressed from the compression means 200 to the second heat exchange means 202. The second heat exchange means 208 operates in the heating mode and the first heat exchange means 202 operates in the cooling mode.

When the four-way opening and closing member 201 is opened toward the first heat exchange means 202 as described above, the low-temperature, low-pressure gas refrigerant from the compression means 200 is converted into a high-temperature, high-pressure gas state, and thus the four-way opening and closing member 201. Is supplied to the first heat exchange means (202).

The first heat exchange means 202 is heated by dissipating heat that is absorbed in the high-temperature, high-pressure gaseous refrigerant of the compression means 200 supplied through the four-way opening and closing member 201 and the electronic expansion member ( 205 changes the opening and closing degree according to the maximum opening degree operation amount P 'according to the target superheat degree SHo of the user input from the microcomputer 206 to adjust the amount of refrigerant in the liquid phase at room temperature and high pressure to control the capillary tube 207. Is supplied to the second heat exchange means 208, wherein the first, second temperature sensing member 203 is provided in the inlet pipe (202a) and the outlet pipe (202b) of the first heat exchange means (202) ( 204 detects the inlet side temperature T1 and the outlet side temperature T2 of the first heat exchange means 202 and inputs them to the microcomputer 206 described above.

Accordingly, as described in FIG. 6, the microcomputer 206 is operated according to the operating frequency of the electronic expansion member 205 (this is a frequency known by itself as the operation control is performed) (f = Hz). The correction amount ΔT in anticipation of the pressure loss in one heat exchange means 202 is obtained (ST1).

That is, the correction amount [Delta] T is obtained in proportion to the operating frequency of the electronic expansion member 205 as shown in FIG.

When the correction amount ΔT is obtained as described above, the saturation temperature value Te is obtained by the difference between the inlet side temperature T1 and the correction amount ΔT of the first heat exchange means 202 detected by the first temperature sensing member 203. (ST2) Then, the superheat degree SH is determined by the difference between the saturation temperature value Te and the outlet temperature T2 of the first heat exchange means 202 detected by the second temperature sensing member 204 (ST3). ).

When the superheat degree SH is obtained as described above, the microcomputer 206 detects the target superheat degree SHo set by the user and the first and second temperature sensing members 203 and 204. Subtract (SH) to obtain the deviation value ep (ST4).

That is, the deviation value ep is obtained as SH-SHo, and the increment ΔT of the opening degree P of the electronic expansion member 205 is obtained from the deviation value ep (ST5).

In the above, the opening degree increment ΔT of the electronic expansion member 205 can be obtained as shown in Equation 1 below.

ΔP = A {ep (t) −eP (t−1)} + ts {ep (t) + ep (t−1)} / 2T... … … … … … … … (Equation 1)

In Equation (1), ts is a sampling time, A is a proportionality constant, T is an integration time, and ep (t) is a deviation between the superheat degree SH and the target superheat degree SHo.

In this way, when the opening degree increment ΔT of the electronic expansion member 205 is obtained, the increment ΔT and the opening degree P (t-1) of the previous electronic expansion member 205 are added to the electronic expansion member ( The final opening degree manipulated value P '(t) of 205 is obtained (ST6).

That is, the final opening degree manipulated value P '(t) of the electronic expansion member 205 is obtained by the following equation (2).

P '(t) = R (t-1) + ΔP... … … … … … … … (2)

When the final opening degree operation amount P (t) is obtained as described above, it is supplied as a pulse to the electronic expansion member 205. The pendulum expansion member 205 is composed of a stem motor 205c as shown in FIG.

The stem motor 205c of the electromagnetic expansion member 205 generates a magnetic field in the stator coil 205a according to the pulse output from the microcomputer 206 so that the rotor 205b rotates step by step. When the electron 205b rotates in stages, the shaft of the stem motor 205c rotates clockwise or counterclockwise according to the rotation direction of the rotor 205b, and the valve shaft 205d fixed to the shaft As the shaft of the step motor 205c rotates, the opening and closing of the inlet and outlet pipes 205e and 205f are finely adjusted by performing fine linear up and down reciprocation.

Here, as shown in FIG. 4, the opening degree is changed according to the pulse signal output from the microcomputer 206 to adjust the flow rate.

That is, as shown in FIG. 4, the flow rate decreases as the valve shaft 205d of the electromagnetic expansion member 205 is fully closed and the coil applied current (mA) increases.

As a result, the electronic expansion member 205 is completely open when the applied voltage is 0V, and is closed when the applied voltage is 1V.

In addition, the coil's applied current is 0mA and 300mA, respectively.

Referring to FIG. 5, the step motor 205c of the electronic expansion member 205 is operated in 240 steps until it is fully opened in a fully closed state.

Therefore, when 130 pulses are input from the microcomputer 206, the degree of opening rapidly changes in the vicinity thereof, and the flow rate is about five times the flow rate in the vicinity of 130 pulses at the fully open position, and the electron expansion is performed at 130 or less. The opening degree of the member 205 is gradually changed so that the flow of the refrigerant is precisely stepped to control the degree of superheat of the outlet of the first heat exchange means 202.

Meanwhile, at room temperature and high pressure supplied through the outlet pipe 202b of the first heat exchange means 202, the liquid refrigerant at room temperature and high pressure supplied through the outlet pipe 202b of the first heat exchange means 202 may be As described above, the amount of flow is adjusted through the inlet and outlet tubes 205e and 205f of the electronic expansion member 205 according to the pulse signal of the final opening degree operation amount P '(t) of the microcomputer 206. Supplied to the capillary 207.

The liquid refrigerant of room temperature and high pressure whose amount is controlled through the electronic expansion member 205 is changed into a liquid refrigerant of low temperature and low pressure while passing through the capillary tube 207 and is supplied to the second heat exchange means 208.

The second heat exchange means 208 is a low-temperature low-pressure liquid refrigerant through the capillary tube 207 is converted into a gas refrigerant while making a heat exchange with the air in the room to change the air in the room to a low temperature, the refrigerant changed into the gas phase Again supplied to the compression means (200).

In addition, when the four-side opening and closing member 201 is opened toward the second heat exchange means 208, the second heat exchange means 208 acts as a condenser to heat, and the first heat exchange means 202 acts as an evaporator. Cool down.

As described in detail above, according to the exemplary embodiment of the present invention, the electronic expansion member is finely controlled according to the load variation and the frequency of the refrigeration cycle, so that the stable state can be maintained regardless of the load variation on the refrigeration cycle. There is an effect that the refrigeration cycle is stabilized by proportionally adjusting the refrigerant flow rate.

Claims (6)

Predicting the pressure loss of the heat exchange means according to the operating frequency of the control target to cut off the refrigerant supply, and obtaining a correction amount ΔT1, and saturating with the difference between the inlet side temperature T1 and the correction amount ΔT1 obtained from the heat exchange means. Obtaining the temperature value Te, calculating the superheat degree SH by the difference between the temperature value Te and the outlet temperature T2 obtained from the heat exchange means, the obtained superheat degree SH and the user's target superheat degree Deriving the deviation (ep) by subtracting (SHo) and calculating the opening degree increase (ΔP) of the control object to cut off the refrigerant supply using the deviation (ep), and the current opening degree increase and the previous opening obtained above. Refrigerant flow rate control method of the inverter room air conditioner, characterized in that the step of adjusting the refrigerant flow into the heat exchange means by obtaining the final opening degree operation amount (P ') of the control target according to the accuracy value. The method of controlling a refrigerant flow rate of an inverter room air conditioner according to claim 1, wherein a final opening degree operation amount is obtained by adding an increase in opening degree and a previous opening degree value. The method for controlling the refrigerant flow rate of an inverter room air conditioner according to claim 1, wherein the opening degree steam content ΔP is obtained by the following equation. ΔP = A {ep (t) -ep (t-1)} + ts {ep (t) + ep (t-1)} / 2T Where ts is the sampling time, A is the proportional constant, T is the integral time, and ep (t) is the deviation between superheat SH and target superheat SH. Among the first and second heat exchange means and the electronic expansion member which is installed between the inlet and outlet of the first and second heat exchange means for condensing or evaporating the refrigerant obtained by the compression means to exchange heat with the outside air. Means for obtaining a correction amount ΔT1 for estimating the pressure loss of the heat exchange means according to the operating frequency of the first and second temperature sensing members and the electromagnetic expansion members which are installed at any one of the inlet and outlet sides and sense the inlet and outlet temperature. And a means for subtracting the obtained correction amount and the inlet side temperature T2 of the heat exchange means obtained from the first temperature sensing member to obtain a saturation temperature value Te, and the obtained saturation temperature value and the second temperature reducing member. Means for obtaining the superheat degree SH by subtracting the outlet side temperature T2 of the heat exchange means, and means for subtracting the obtained superheat degree and the target superheat degree of the user to obtain a deviation ep. An adjustment means for obtaining the opening degree increment ΔP of the electronic expansion member by using a difference, and the final opening degree operation amount by adding the increase obtained by the adjustment means and the previous opening degree P (tl) of the electronic expansion member. Refrigerant flow rate control device of the inverter room air conditioner, characterized in that consisting of means for controlling the opening of the electronic expansion member step by step. 5. The apparatus of claim 4, wherein the electromagnetic expansion member is formed of a depth motor. 6. The refrigerant flow control apparatus of an inverter room air conditioner according to claim 5, wherein the electromagnetic expansion member is configured to open and close the inlet and outlet pipes by converting the stem rotational motion of the stem motor into a vertical straight step motion.