KR20210094409A - Air conditioner and method for controlling for the same - Google Patents

Abstract

The present invention relates to an air conditioner and a method for controlling the same, which calculates the intensity of oscillation in response to a change in cycle or a change in room temperature in controlling the flow rate of a refrigerant and calculates a compensation value for the operating frequency, performs compensation control for the compressor at the final operating frequency to which the compensation value is applied, thereby solving cycle instability during flow control of the refrigerant, and stably controlling the indoor temperature to provide a comfortable indoor environment.

Description

Air conditioner and method for controlling the same

The present invention relates to an air conditioner and a control method therefor, and more particularly, to an air conditioner and a control method thereof for minimizing a change in indoor temperature while controlling a flow rate.

The air conditioner includes an indoor unit configured as a heat exchanger and an outdoor unit configured as a compressor and a heat exchanger. The outdoor unit and the indoor unit are connected through a refrigerant pipe, and the refrigerant compressed from the compressor of the outdoor unit is supplied to the heat exchanger of the indoor unit through the refrigerant pipe, and the refrigerant exchanged in the heat exchanger of the indoor unit is again introduced into the compressor of the outdoor unit through the refrigerant pipe.

The indoor unit performs heat exchange between the indoor air and the refrigerant through a pressure change of the refrigerant supplied to the heat exchanger. Accordingly, the indoor unit discharges cold and hot air into the room through heat exchange using the refrigerant.

The flow rate of the refrigerant supplied from the outdoor unit to the indoor unit is controlled by a compressor.

In the air conditioner, when controlling the flow rate of refrigerant through the compressor, when controlling the compressor with gain, oscillation occurs in the cycle as the indoor thermal load situation (partial load) or the length of the pipe becomes longer. There is a problem that arises.

This oscillation phenomenon has a problem in that it gives discomfort to a user located in an indoor space as the indoor temperature is changed.

In addition, due to the oscillation phenomenon, as the refrigerant flow rate is excessively fluctuated, the possibility of wet compression increases and the life of the compressor may decrease.

In Korean Patent Laid-Open Patent Publication No. 10-2017-0016727, a compensation value is applied to reduce the operating frequency of the compressor according to the indoor load while the air conditioner is changed to the settlement control after the start control.

Such a conventional air conditioner compensates according to an indoor load and an indoor temperature, but there is a problem in that it is limited to a time point when the air conditioner is switched to normal control after starting. In addition, the conventional air conditioner is configured to collectively compensate for the gain, so there is a limitation in that the compensation is collectively performed regardless of the change amount of the cycle, and there is a problem that a separate control for cycle safety is required.

Therefore, there is a need for a method for minimizing oscillation and stably controlling the cycle in the control of the refrigerant flow rate using the compressor.

Republic of Korea Patent Publication 10-2017-0016727

An object of the present invention is to provide an air conditioner for stably controlling an indoor temperature in controlling the flow rate of a refrigerant and a control method therefor.

An object of the present invention is to provide an air conditioner that minimizes oscillation of a cycle that occurs while controlling a flow rate of a refrigerant, and a control method therefor.

An object of the present invention is to solve the instability of the cycle caused by the increase in the length of the indoor load and the refrigerant pipe.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, an air conditioner and a control method thereof according to an embodiment of the present invention provide compensation control for a compressor in response to a change in cycle or a change in room temperature in controlling the flow rate of a refrigerant. characterized in that

The present invention is characterized in that the compressor is controlled in response to the cycle change amount by setting a compensation value for the compressor in response to the cycle change.

The present invention is characterized in that the compensation is proportionally determined according to the change width of the cycle.

The present invention is characterized in that the intensity of oscillation is calculated by measuring and quantifying the change in the cycle, and the oscillation according to the change in the cycle is reduced by applying it to the frequency control of the compressor.

The present invention is characterized in that the flow rate of the refrigerant is controlled in response to the error between the target control value and the present value of the compressor, and the rate of change of the error.

The present invention is characterized in that the indoor temperature is controlled by setting the target pressure of the compressor using the difference between the desired temperature and the indoor temperature, and setting the operating frequency corresponding to the target pressure.

The present invention is characterized in that when oscillation occurs, a response speed according to a pressure change is calculated and a compensation value is set proportionally in response to the response speed to reduce the generated oscillation.

The air conditioner of the present invention includes a compressor; a sensor unit including a plurality of sensors to detect temperature and refrigerant pressure; a compressor driving unit for driving the compressor to operate at a set operating frequency; It is determined whether oscillation occurs in response to a change in room temperature or the operating frequency of the compressor, and when the oscillation occurs, a compensation value corresponding to the intensity of the oscillation is calculated, and the final operation to which the compensation value is applied and a control unit for performing compensation control on the compressor so that the compressor operates at a frequency.

The control unit may calculate the intensity of the oscillation based on a response speed to a pressure change based on the pressure of the refrigerant sensed through the sensor unit.

The control unit may calculate the response speed from the time it takes for the pressure to change in a section in which the pressure increases and a section in which the pressure decreases within a predetermined pressure range based on the target pressure.

The control unit is configured to adjust the pressure of the refrigerant from the third pressure to the first pressure with respect to a first pressure lower than the target pressure and a third pressure higher than the target pressure based on a second pressure that is the target pressure. It is characterized in that the response speed is calculated from a first time required to reach the first time and a second time required for the pressure of the refrigerant to reach the third pressure from the first pressure.

The control unit calculates a final increment for the operating frequency as the compensation value by multiplying the intensity of the oscillation by the increase in the operating frequency, and sets the final operating frequency by adding the compensation value and the operating frequency do.

The control method of the air conditioner according to the present invention includes the steps of setting an operating frequency according to the operation setting and operating the compressor; determining whether oscillation has occurred according to a change amount of room temperature or an operating frequency of a compressor; when oscillation occurs, calculating a compensation value corresponding to the strength of the oscillation; calculating a final operating frequency to which the compensation value is applied; and controlling the compressor according to the final operating frequency to perform compensation control.

The air conditioner and its control method of the present invention have an effect of stabilizing the indoor temperature through compensation control for cycle changes that occur when controlling the flow rate of a refrigerant.

The present invention can stabilize the cycle by determining the compensation proportionally according to the change width of the cycle.

The present invention can prevent the wet compression phenomenon due to oscillation of the cycle.

The present invention has the effect of preventing damage to the compressor due to cycle oscillation and extending the lifespan.

The present invention can provide a comfortable indoor environment to the user by stably controlling the indoor temperature.

According to the present invention, even when cycle oscillation occurs, oscillation can be reduced through compensation control proportional to the time of oscillation change.

According to the present invention, even when cycle oscillation occurs, the oscillation can be reduced within a short time by controlling the compressor according to the intensity of the oscillation.

1 is a schematic diagram of an outdoor unit and an indoor unit of an air conditioner according to an embodiment of the present invention.
2 is a diagram illustrating an air conditioner including a plurality of outdoor units and indoor units according to an embodiment of the present invention.
3 is a block diagram schematically illustrating a control configuration of an air conditioner according to an embodiment of the present invention.
4 is a diagram referenced to explain a method for measuring oscillation of an air conditioner according to an embodiment of the present invention.
5 is a diagram referenced for explaining a cycle change of the air conditioner according to an embodiment of the present invention.
6 is a diagram referenced for explaining a temperature change of the air conditioner according to an embodiment of the present invention.
7 is a diagram referenced to explain compensation control of the air conditioner according to an embodiment of the present invention.
8 is a diagram referenced to explain a method for controlling an air conditioner according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout. The control configuration of the present invention may consist of at least one processor.

1 is a schematic diagram of an outdoor unit and an indoor unit of an air conditioner according to an embodiment of the present invention.

As shown in FIG. 1 , the air conditioner according to the present invention may include an indoor unit 20 and an outdoor unit 10 connected to the indoor unit 20 .

The indoor unit 20 of the air conditioner may be any one of a stand-type air conditioner, a wall-mounted air conditioner, and a ceiling type air conditioner.

At this time, the outdoor unit 10 supplies the compressed refrigerant to the connected indoor unit 20 .

The indoor unit 20 receives refrigerant from the outdoor unit 10 and discharges cold and hot air into the room.

The outdoor unit (10) includes a compressor (102) serving to compress a refrigerant, a compressor electric motor (102b) for driving the compressor, an outdoor heat exchanger (104) serving to radiate heat from the compressed refrigerant; An outdoor blower 105 comprising an outdoor fan 105a disposed on one side of the heat exchanger 104 to promote heat dissipation of the refrigerant and an electric motor 105b rotating the outdoor fan 105a, and expansion to expand the condensed refrigerant The mechanism 106, the cooling/heating switching valve 111 for changing the flow path of the compressed refrigerant, and the accumulator 103 for temporarily storing the vaporized refrigerant to remove moisture and foreign substances and then supplying the refrigerant at a constant pressure to the compressor etc. At least one of an inverter compressor and a constant speed compressor may be used as the compressor 102 .

In addition, the outdoor unit 10 includes at least one pressure sensor (not shown) for measuring pressure, at least one temperature sensor (not shown) for measuring temperature, and a control for controlling the operation of the outdoor unit and communicating with other units. configuration may be included. The outdoor unit 10 may further include a plurality of sensors, valves, supercoolers, and the like, but a description thereof will be omitted below.

The indoor unit 20 includes an indoor heat exchanger 108 disposed indoors to perform a cooling/heating function, an indoor fan 109a disposed at one side of the indoor heat exchanger 108 to promote heat dissipation of the refrigerant, and an indoor unit. and an indoor blower 109 including an electric motor 109b that rotates the fan 109a.

In addition, the indoor unit 20 includes a discharge port 13 for discharging heat-exchanged air, and a wind direction control means (not shown) for opening and closing the discharge port and controlling the direction of the discharged air is provided. The indoor unit controls the intake air and the discharged air by controlling the rotation speed of the indoor unit fan, and adjusts the air volume. The indoor units 1 and 2 may further include an input/output unit 18 for displaying the operation state and setting information of the indoor unit and inputting setting data.

At least one indoor heat exchanger 108 may be installed.

In addition, the air conditioner may be configured as an air conditioner for cooling the room, or may be configured as a heat pump for cooling or heating the room.

2 is a diagram illustrating an air conditioner including an outdoor unit and an indoor unit according to an embodiment of the present invention.

Referring to FIG. 2 , the air conditioner includes at least one outdoor unit 10 and at least one indoor unit 20 . In addition, the air conditioner may include a controller (not shown) or remote controllers 31 and 32, and may further include a terminal (not shown) that operates as a controller by accessing it through an external network such as the Internet.

In addition to the indoor unit and the outdoor unit, the air conditioner is composed of a system and may include a ventilation device, an air purifier, a humidifier, a heater, and the like, and may further include units such as a chiller, an air conditioning unit, and a cooling tower depending on the scale. The air conditioner may operate in conjunction with the operation of the indoor unit and the outdoor unit by connecting each unit to each other. In addition, the air conditioner may operate in connection with a building, a mobile device, a security device, an alarm device, and the like.

The air conditioner may transmit/receive data to each other in a wired communication method or a wireless communication method. The outdoor unit and the indoor unit may be connected to a controller (not shown) by wire or wirelessly to operate under the control of the controller.

The remote controllers 31 and 32 are connected to the indoor unit through a wired or wireless communication method to input a user command to the indoor unit, and receive and output data from the indoor unit. The remote controller may transmit a user command to the indoor unit and perform one-way communication in which data from the indoor unit is not received, or perform two-way communication in which data is transmitted/received between the indoor unit and the indoor unit according to a connection method with the indoor unit.

The controller controls the operation of the indoor unit 20 and the outdoor unit 10 in response to an input user command, periodically receives and stores data on the operation state of the indoor unit and the outdoor unit corresponding thereto, and stores the operation state through the monitoring screen. can be printed out. The controller may perform operation setting, lock setting, schedule control, group control, peak control for power use, demand control, and the like for the indoor unit 20 .

The terminal (not shown) operates as a second controller connected from the outside of the air conditioner network. The terminal may be a mobile terminal that communicates through a mobile communication network, and a PDA, PC, tablet PC, smartphone, control terminal, etc. may be used, and any terminal capable of installing a program for controlling the air conditioner may be used. can

The outdoor unit 10 is connected to the indoor unit 20 through a refrigerant pipe, respectively, and supplies the refrigerant to the indoor unit 20 . In addition, the outdoor unit 10 periodically communicates with the plurality of indoor units 20 to transmit/receive data to and from each other, and change the operation according to the operation setting changed from the indoor unit.

Meanwhile, when a plurality of outdoor units are connected, each outdoor unit may be connected to a plurality of indoor units, and the air conditioner may further include a distributor (not shown) to supply refrigerant to the plurality of indoor units.

The first outdoor unit or the indoor unit 20 may be connected to a controller, and the first to second indoor units may be connected to the remote controllers 31 and 32, respectively.

The controller displays data information of the indoor unit 20, data information of the outdoor unit 10, valve information of a pipe connecting the indoor unit 20 and the outdoor unit 10, etc. can do. The controller may check the operating state of the indoor unit 20 or the outdoor unit 10 in real time.

Also, the air conditioner may transmit/receive data to and from another air conditioner through a network connection such as the Internet. The air conditioner may connect to an external service center (not shown), a management server (not shown), a database (not shown), etc. through the controller, and may communicate with an external terminal connected through a network.

3 is a block diagram schematically illustrating a control configuration of an air conditioner according to an embodiment of the present invention.

As shown in FIG. 3 , the outdoor unit 10 of the air conditioner includes a sensor unit 140 , a power supply unit 130 , a compressor driving unit 161 , a fan driving unit 162 , a valve control unit 163 , and an input/output unit 190 . ), a memory 120 , a communication unit 150 , and a control unit 110 for controlling overall operations.

Each unit including the control unit 110 may be composed of one or a plurality of microprocessors. In addition to the control unit, each unit of the sensor unit, power supply unit, compressor driving unit, fan driving unit, valve control unit, input/output unit, memory, and communication unit may each include at least one microprocessor. Each unit including the control unit may be connected in a bus (BUS) format to transmit/receive data.

The compressor driving unit 161 , the fan driving unit 162 , and the valve control unit 163 may be configured as one driving unit, and as described above, may be configured independently of each other.

The indoor unit may also include a sensor unit, a power supply unit, a fan driving unit, a valve control unit, an input/output unit, a memory, a communication unit, and a control unit.

The power supply unit 130 supplies operating power to the main body of the outdoor unit. The power supply unit 130 rectifies and smooths the connected commercial power to generate and supply voltages required by each unit. The power supply unit 130 prevents inrush current and generates a constant voltage. Also, the power supply unit 130 may supply operating power to the indoor unit (not shown).

The input/output unit 190 includes at least one of a button, a switch, and a touch input means, an input means (not shown) for inputting a user command or predetermined data, and a display means (not shown) such as LCD, LED, OLED, etc. is configured, and the touch pad may include a layered touch screen. The display means displays the driving setting or operation information in a combination of at least one of a character, an image, a special character, a symbol, an emoticon, and an icon.

In addition, the input/output unit 190 includes an audio output unit (not shown) including a buzzer or speaker for outputting voice guidance, a predetermined warning sound, and an effect sound, and an audio input unit (not shown) including a microphone for receiving a predetermined sound. may include

The display means and the audio output section are output sections.

The memory 120 includes control data for controlling an operation, data on an operation mode, data sensed by the sensor unit 140 , data transmitted/received through the communication unit 150 , input data by the input/output unit 190 , and output Data and data for determining whether an operation is abnormal are stored. The memory 120 stores data that can be read by a microprocessor, ROM, RAM, EPROM, EEPOM, flash memory, HDD (Hard Disk Drive), SSD (Solid State Disk), SDD (Silicon) A storage device such as a disk drive) may be included.

The communication unit 150 includes at least one communication module to transmit and receive data in a wired or wireless communication method.

The communication unit 150 transmits/receives data to and from another device, for example, an indoor unit, another outdoor unit, or a controller. In addition, the communication unit 150 may be connected to a predetermined network to communicate with an external server or terminal. The communication unit 150 transmits and receives data including communication modules such as Wi-Fi and WiBro, as well as short-distance wireless communication such as Zigbee, Bluetooth, and infrared.

The sensor unit 140 includes a plurality of sensors, and the measured data is input to the control unit 110 . The sensor unit 140 includes a temperature sensor (not shown), a pressure sensor (not shown), a humidity sensor (not shown), a current sensor (not shown), and a voltage sensor (not shown).

The temperature sensor is installed in the refrigerant pipe to measure the temperature of the refrigerant pipe, and is installed in the heat exchanger to sense the outdoor temperature and the heat exchanger temperature, respectively.

The pressure sensor is installed in the refrigerant pipe to sense the pressure of the refrigerant flowing through the refrigerant pipe. The pressure sensor is installed in the refrigerant inlet and outlet of the compressor 171, respectively, and is also installed in the heat exchanger.

The compressor driving unit 161 operates the compressors 171 and 102 according to the control command of the control unit 110 . At this time, the compressor driving unit 160 supplies operating power to the motor 102b of the compressor so that the compressor 171 operates at a specific operating frequency. Accordingly, when the low-temperature and low-pressure refrigerant flows in, the compressor 171 compresses it and discharges it as a high-temperature and high-pressure refrigerant.

The fan driving unit 162 controls the driving of the motor 105b provided in the fans 172 and 105 in response to the control command of the controller 110, thereby causing the fan 105a to rotate. The fan driving unit 162 supplies operating power to the fan 172 and controls the fan to rotate at a set rotation speed of the fan 172 . The fan 172 is provided in the outdoor heat exchanger, and the refrigerant supplied from the compressor 171 flows into the heat exchanger to suck in and supply outdoor air to exchange heat with the outdoor air, and discharge the heat-exchanged air to the outdoors. In this case, the fan 172 may be an inverter fan capable of adjusting the rotation speed. The fan 172 includes a motor and a fan, and the fan rotates as the motor operates under the control of the fan driving unit 162 .

The valve control unit 163 may control opening/closing of the plurality of valves 173 provided in the outdoor unit 21 in response to a control command from the control unit 110 , or adjust an opening rate, and may change the flow path of the refrigerant. In this case, the valve control unit 163 may be provided in each of the plurality of valves 173 .

The controller 110 applies a control command to the compressor driving unit 161 to operate the compressor 171 in response to data received from the indoor unit 31 or the controller, and transmits the control command to the fan 172 to the fan driving unit ( 162) is approved. In addition, the control unit 110 applies a control command to the valve control unit 163 to control the opening and closing of each of the plurality of valves 173 to change the flow path and flow rate of the refrigerant according to the operation mode.

The control unit 110 determines the states of the compressor 171 , the refrigerant, and the fan 172 in response to data input from a plurality of sensors of the sensor unit 140 , and generates a control command in response thereto and applies it to each driving unit do.

The controller 110 communicates with the indoor unit 20 at predetermined time intervals through the communication unit 150 to receive data of each indoor unit, and also transmits data of the outdoor unit to the indoor unit 20 .

In addition, the control unit 110 determines whether the operation state of each unit is normal based on the data sensed by the sensor unit 140 and the data stored in the memory 120 , and generates an error. The controller 110 may output an error code for the generated error.

When it is determined that there is an error, the control unit 110 determines whether driving is possible.

In addition, the control unit 110 outputs an error when the operation is impossible due to an error or when the restricted operation is stopped. The control unit 110 transmits error data to the indoor unit through the communication unit so that an error and a notification of operation termination are output through the indoor unit. The indoor unit 20 outputs an operation state, a notification, or an error message according to data received from the outdoor unit 10 .

In addition, the control unit 110 may detect an abnormality with respect to the operating power supplied through the power supply unit 130 , and when an overcurrent or a short circuit is detected, the power may be cut off. The control unit 110 may determine the operating power as a leakage current, an overcurrent, or a normal state through the input signal.

The control unit 110 controls the flow rate of the refrigerant through compensation control for the compressor.

The controller 110 controls the operating frequencies of the compressors 171 and 102 in response to an indoor load and a temperature value during flow rate control. The control unit 110 applies a control command to the compressor driving unit 161, and accordingly, the compressor driving unit 161 applies operating power to the compressor. As the compressor is driven, the refrigerant is supplied from the outdoor unit to the indoor unit and circulated.

The control unit 110 sets a target pressure using the difference between the desired temperature and the room temperature, calculates an operating frequency for achieving the target pressure, and applies a control command to the compressor driving unit 161 .

When cycle oscillation occurs, the controller 110 measures the intensity of the oscillation, sets a compensation value for the compressor in response thereto, and performs compensation control on the compressor.

The controller 110 controls the compressor to reduce the oscillation by measuring the change time of the current value compared to the target for the generated oscillation, and setting a compensation value according to the ratio.

The air conditioner may control the change in the indoor temperature by controlling the discharge temperature of the indoor unit according to the reduction of oscillation of the cycle.

4 is a diagram referenced to explain a method for measuring oscillation of an air conditioner according to an embodiment of the present invention.

The air conditioner may reduce or prevent the oscillation from occurring through compensation control for the oscillation phenomenon.

As shown in FIG. 4 , when oscillation occurs, the controller 110 measures the intensity of the oscillation and performs compensation control according to the measured intensity.

During operation of the compressor, the sensor unit 140 may sense the pressure of the refrigerant discharged from the compressor. When oscillation occurs, the pressure of the refrigerant also changes.

The control unit 110 calculates the intensity of the oscillation in response to the pressure value sensed by the sensor unit 140 .

The control unit 110 measures the time it takes for the pressure to change within a range of a predetermined pressure value, that is, within the range of the first pressure H1 and the third pressure H3 based on the second pressure H2, which is the target pressure. Thus, the intensity (magnitude) of the oscillation can be calculated. The first pressure is less than the second pressure, and the third pressure is greater than the second pressure.

The controller 110 may derive the target pressure by using the difference between the desired temperature and the current indoor temperature.

The control unit 110 is based on a point at which the first pressure and the third pressure H3 are measured based on the second pressure H2, but the pressure is changed in the section in which the pressure decreases and the section in which the pressure is increased, respectively. time can be measured.

For example, the controller 110 may include a second point P2 and a third point P3 at which the first pressure H1 is measured, and a first point P1 and a second point P1 at which the third pressure H3 is measured. The strength (magnitude) of the oscillation can be measured based on the 4 points (P4).

The control unit 110 measures the section in which the pressure of the refrigerant decreases from the third pressure H3 to the first pressure H1, that is, the 21st time T21 from the first point P1 to the second point. do.

Since the first point P1 is the eleventh time T11 and the second point P2 is the twelfth time T12, respectively, the specified pressure is measured, so the twenty-first time T21 is the eleventh time T11 and the second point P2. It becomes an interval of 12 hours (T12).

In addition, the control unit 110 is a section in which the pressure of the refrigerant increases from the first pressure (H1) to the third pressure (H3), that is, the 22nd time from the third point (P3) to the fourth point (P4). (T22) is measured.

Since the third point P3 is the thirteenth time T13 and the fourth point P4 is the fourteenth time T14, the 22nd time T22 is the thirteenth time T13 and the 14th time T14. becomes an interval.

The control unit 110 may calculate the intensity (magnitude) of the oscillation, that is, K, as shown in Equation 1 below.

The intensity of the oscillation (K) is a value obtained by multiplying the absolute value of the 21st time (T21) by the absolute value of the 22nd time (T22) multiplied by -0.7, which is a specified first constant, and then 1 is added as a second constant can be calculated as The strength of the oscillation may indicate the strength of the oscillation.

That is, the controller calculates the intensity of the oscillation as a value obtained by subtracting 70% of a value obtained by dividing the 21st time by the 22nd time.

The controller 110 calculates the operating frequency of the compressor for forming the target pressure with respect to the set target pressure H2 using the difference between the desired temperature and the current indoor temperature.

The control unit 110 controls the compressor driving unit 161 by setting the calculated operating frequency, and the compressor 171 operates at the set operating frequency by the compressor driving unit.

The refrigerant discharges a high-temperature and high-pressure refrigerant by the operation of the compressor 171 , and the refrigerant flows into the indoor unit and heat exchanges, thereby discharging cold and hot air into the room. As the discharged heat-exchanged air is discharged into the indoor space, the indoor temperature may change to reach a desired temperature.

The controller 110 determines that oscillation has occurred when oscillation occurs, that is, when the operating frequency of the compressor changes as shown in FIG. 6 to be described later while controlling the compressor with the set operating frequency. Also, the controller 110 may determine that oscillation has occurred when the discharge temperature repeatedly increases and decreases within a specified time, that is, when it changes as shown in FIG. 5 to be described later.

When oscillation occurs, the control unit 110 calculates the strength (K) of the oscillation based on Equation 1 as above, and applies it to the increment of the operating frequency to perform compensation control for the compressor.

The control unit 110 calculates a final increase in the operating frequency by multiplying the increase in the operating frequency by the strength (K) of the oscillation.

The control unit 110 sets the final operating frequency by adding up the current operating frequency and the final increment. The control unit 110 applies the final operating frequency to the compressor driving unit 161, and the compressor driving unit controls the compressor to the final operating frequency.

Accordingly, the compressor 171 discharges a high-temperature and high-pressure refrigerant, and the refrigerant having a target pressure is discharged and introduced into the indoor unit.

5 is a diagram referenced to explain a cycle change of the air conditioner according to an embodiment of the present invention, and FIG. 6 is a diagram referenced to explain a temperature change of the air conditioner according to an embodiment of the present invention.

When the air conditioner performs flow rate control using a compressor, as shown in FIGS. 5 and 6 , oscillation may occur in a cycle. In contrast, the controller 110 may reduce the oscillation by calculating the intensity of the oscillation and performing compensation control for the operating frequency of the compressor as described above.

The first graph (S1) is the average temperature according to the compensation control, the second graph (S2) is the average temperature when oscillation occurs, the third graph (S3) is the operating frequency of the compressor according to the compensation control, 4 The graph S4 shows the operating frequency when oscillation occurs.

The control unit 110 controls the main flow rate according to the error between the control target value and the current value and the error change rate through the compressor. At this time, when controlling the main flow rate, the gain of the compressor is determined according to the response speed in the standard region. As shown in the second graph S2 and the fourth graph S4 of FIG. 6 , oscillations may occur in temperature and operating frequency.

When the control of the flow rate of the refrigerant is started, even if the operating frequency of the compressor is set constant, when the control fails depending on the pipe length and the size of the indoor load (partial load), the compressor operating frequency increases and decreases rather than maintains the set value. Oscillation occurs repeatedly.

When the control fails during flow rate control, as shown in the fourth graph (S4), an oscillation occurs in which the operating frequency of the compressor repeatedly increases and decreases within the 10th to 40th Hz range.

In addition, when the control fails according to the flow control of the compressor, as described above, the room temperature also changes as oscillation occurs in the operating frequency of the compressor. As shown in the second graph, the range of change in the indoor temperature is greatly increased. The indoor temperature does not maintain the target temperature of 24 degrees, but increases or decreases within the range of 24 to 26 degrees to maintain an unstable state. In particular, frequent temperature changes can occur within a short period of time.

Such oscillation may cause instability of the room temperature, and may cause damage to the compressor and consequently reduced lifespan.

The oscillation phenomenon may occur depending on the indoor load of the air conditioner, that is, the number of operating indoor units, the target temperature, and the length of the refrigerant pipe, and the degree of the oscillation may be different.

When oscillation occurs, the control unit 110 calculates the strength (K) of the oscillation and reflects it in the increment with respect to the operating frequency of the compressor, thereby performing compensation control.

In the compensation control, as shown in the third graph (S3), the operating frequency of the compressor is about 30 Hz after initial startup, and it can be seen that a constant value is maintained within a predetermined error range.

In addition, as shown in the first graph S1 , through the compensation control, the indoor temperature (average) is reduced to a target temperature according to the cooling operation, and can be maintained at about 24 degrees within a predetermined error range.

The oscillation phenomenon may occur depending on the indoor load of the air conditioner, that is, the number of operating indoor units, the target temperature, and the length of the refrigerant pipe, and the degree of the oscillation may be different.

7 is a diagram referenced to explain compensation control of the air conditioner according to an embodiment of the present invention.

As shown in FIG. 7 , the control unit 110 performs compensation control for the operating frequency of the compressor with respect to the oscillation phenomenon.

The control unit 110 calculates the difference based on the input desired temperature T1 and the indoor temperature T2 measured through the sensor unit 140, and in response to the temperature difference, the target pressure (H) for the refrigerant to calculate In this case, the indoor temperature T2 may be received from the indoor unit 20 .

The control unit 110 calculates an operating frequency O1 for forming a target pressure H for the refrigerant discharged from the compressor.

The control unit 110 applies the operating frequency O1 to the compressor driving unit 161, and the compressor operates according to the set operating frequency O1.

On the other hand, when oscillation occurs, the control unit 110 calculates a response speed T3, which is a time required for a change in pressure, and calculates an oscillation strength K in response to the response speed T3. The response speed is the time until a specific pressure is reached, and is calculated based on the time measured in the section where the pressure increases and the section where the pressure decreases. For example, in FIG. 4 described above, the twenty-first time T21 from the first point P1 to the second point P2 and the twenty-second time T21 from the third point P3 to the fourth point P4 ( T22).

The controller 110 multiplies the increment of the operating frequency by the intensity K of the oscillation and calculates the final increment as the compensation value C1.

The control unit 110 calculates the final operating frequency O2 by summing the compensation value C1 with the operating frequency O1.

The control unit 110 applies the final operating frequency O2 to the compressor driving unit 161, and accordingly the compressor 171 operates to supply the refrigerant to the indoor unit.

The control unit 110 may reduce oscillation by repeatedly performing such compensation control.

8 is a diagram referenced to explain a method for controlling an air conditioner according to an embodiment of the present invention.

As shown in FIG. 8 , the operation setting of the air conditioner is input from the indoor unit 20 or the remote controllers 31 and 32, and accordingly, the air conditioner starts to operate by cooling or heating.

When inputting the operation setting, the desired temperature is input (S310). The indoor unit 20 senses the indoor temperature and transmits it to the outdoor unit 10 (S320). The indoor unit and the outdoor unit may periodically communicate using a wired or wireless communication method.

The control unit 110 of the outdoor unit 10 applies a control command to the compressor driving unit 161 to operate the compressor 171 according to the operation setting.

The controller 110 calculates a difference value between the desired temperature and the indoor temperature, and sets the operating frequency of the compressor in response to the temperature difference. The compressor driving unit 161 operates the compressor 171 according to the set operating frequency. In addition, the compressor driving unit 161 controls the flow rate of the refrigerant in response to the indoor load (S340).

The control unit 110 determines whether oscillation occurs according to the amount of change in the room temperature or the operating frequency of the compressor (S350). 5 and 6 as described above, when the indoor temperature is changed within a short time or the operating frequency is repeatedly increased and decreased, the controller 110 may determine that oscillation has occurred.

The control unit 110 calculates a response speed according to time when the pressure is changed, and calculates the intensity of oscillation in response to the response speed T3. Also, the control unit 110 calculates a compensation value C1 for the compressor operating frequency in response to the intensity of the oscillation (S360).

The response speed T3 may be calculated from the times T21 and T22 required for the pressure to reach a specified value in the section in which the pressure increases and the section in which the pressure decreases. The strength (K) of the oscillation can be calculated according to the response speed from Equation 1 described above. In addition, the compensation value C1 may be calculated as a final increment by multiplying the intensity of oscillation by the increment of the operating frequency.

The control unit 110 calculates a final operating frequency, which is a control value for the compressor, by summing the current operating frequency and the compensation value C1 (S370).

The controller 110 applies the final operating frequency to the compressor driving unit 161, and the compressor driving unit 161 controls the compressor 171 to operate according to the final operating frequency (S380).

Accordingly, the air conditioner can reduce the generated oscillation and stabilize the indoor temperature.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

10: indoor unit 20: outdoor unit
50: controller
110: control unit 140: sensor unit
160: compressor driving unit 102, 171: compressor

Claims (19)

compressor;
a sensor unit including a plurality of sensors to detect temperature and refrigerant pressure;
a compressor driving unit for driving the compressor to operate at a set operating frequency;
It is determined whether oscillation occurs in response to a change in room temperature or the operating frequency of the compressor, and when the oscillation occurs, a compensation value corresponding to the intensity of the oscillation is calculated, and the final operation to which the compensation value is applied An air conditioner comprising a; a control unit for performing compensation control for the compressor so that the compressor operates at a frequency. The method of claim 1,
The control unit determines that oscillation has occurred when the indoor temperature received from the indoor unit repeats increasing and decreasing within a predetermined time. The method of claim 1,
The control unit determines that oscillation has occurred when the operating frequency of the compressor repeatedly increases and decreases to a value out of the operating frequency. The method of claim 1,
The control unit controls the main flow rate of the refrigerant in response to the error between the control target value and the present value for the compressor and the error change rate, and determines whether oscillation occurs when the main flow rate is controlled. Air harmonizer. The method of claim 1,
and the control unit calculates the intensity of the oscillation based on a response speed to a pressure change based on the pressure of the refrigerant sensed through the sensor unit. The method of claim 1,
The controller is configured to calculate a final increase in the operating frequency as the compensation value by multiplying the intensity of the oscillation by the increase in the operating frequency. The method of claim 1,
The controller is configured to add the compensation value and the operating frequency to set the final operating frequency to perform the compensation control. 6. The method of claim 5,
The control unit calculates the response speed from the time it takes for the pressure to change in a section in which the pressure increases and the section in which the pressure decreases within a predetermined pressure range based on the target pressure. 9. The method of claim 8,
The control unit, based on the second pressure, which is the target pressure, with respect to a first pressure lower than the target pressure and a third pressure higher than the target pressure,
The response speed from a first time required for the pressure of the refrigerant to reach the first pressure from the third pressure and a second time required for the pressure of the refrigerant to reach the third pressure from the first pressure Air conditioner, characterized in that to calculate. 10. The method of claim 9,
The controller is configured to calculate the intensity of the oscillation by multiplying a value obtained by dividing the first time by the second time by a specified first constant and then summing the second constant. 10. The method of claim 9,
The control unit calculates the intensity of the oscillation according to the following equation,

However, K _A is the oscillation strength, T21 is the first time it takes for the pressure to change in the section where the pressure decreases, T22 is the second time it takes for the pressure to change in the section where the pressure increases, and the first constant is - 0.7, the second constant is an air conditioner, characterized in that 1. The method of claim 1,
The control unit sets the target pressure by using the difference between the desired temperature and the current indoor temperature,
Air conditioner, characterized in that for setting the operating frequency for forming the target pressure. operating the compressor by setting the operating frequency according to the operation setting;
determining whether oscillation has occurred according to an amount of change in the room temperature or the operating frequency of the compressor;
when oscillation occurs, calculating a compensation value corresponding to the strength of the oscillation;
calculating a final operating frequency to which the compensation value is applied; and
and controlling the compressor according to the final operating frequency to perform compensation control. 14. The method of claim 13,
calculating a difference between a desired temperature and a room temperature, and setting the operating frequency of the compressor in response to the temperature difference; A control method of an air conditioner comprising a. 14. The method of claim 13,
The air conditioner further comprising the step of determining that the oscillation has occurred in any one of the case where the indoor temperature varies within a short time or the operating frequency of the compressor repeats increasing and decreasing to a value out of the operating frequency control method. 14. The method of claim 13,
Calculating the compensation value includes:
calculating a response speed according to time when the pressure of the refrigerant changes;
calculating the intensity of the oscillation in response to the response speed; and
and calculating a final increment calculated by multiplying the intensity of the oscillation by an increment of an operating frequency as the compensation value. 17. The method of claim 16,
Calculating the response speed from the first time required for the pressure to reach the specified value in the section where the pressure of the refrigerant is decreased and the second time required for the pressure to reach the specified value in the section where the pressure of the refrigerant is increased A control method of an air conditioner characterized in that. 18. The method of claim 17,
Based on a second pressure that is a target pressure, the control method of an air conditioner, characterized in that the response speed is calculated for a pressure section for a first pressure lower than the target pressure and a third pressure higher than the target pressure . 14. The method of claim 13,
The control method of the air conditioner, characterized in that by summing the current operating frequency and the compensation value to calculate the final operating frequency, which is a control value for the compressor.

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