KR19990010065A - Compressor Control Device and Method of Air Conditioner - Google Patents

Abstract

The present invention relates to a compressor control apparatus and a method of an air conditioner, the compressor starting at an operating frequency determined according to the outdoor conditions and the indoor unit instructions, the band heater for preheating the compressor, the power of the band heater constant An air conditioner having a thermostat for controlling on / off according to temperature, comprising: a compressor temperature sensing means for sensing a surface temperature of the compressor, an outdoor temperature sensing means for sensing an outdoor temperature, and the compressor temperature sensing means; Control means for waiting the start of the compressor in accordance with the detected surface temperature of the compressor, and controlling the start waiting time of the compressor in accordance with the outdoor temperature detected by the outdoor temperature sensing means, for a long time the compressor at low temperature below zero When operating the air conditioner after it has been left unattended or the compressor is disconnected due to disconnection of the band heater. If there is not enough preheating, a waiting time is provided to protect the compressor from starting, thus preventing cylinder wear due to lack of lubrication.

Description

Compressor Control Device and Method of Air Conditioner

The present invention relates to an inverter air conditioner for driving a compressor by varying a frequency, and more particularly, to a compressor control apparatus and a method of an air conditioner for improving the reliability of a compressor during winter use of an air conditioner.

In general, the conventional air conditioner, as shown in Fig. 1, the converter unit 3 for converting the AC input power supplied from the AC power source stage 1 to the DC power, and the DC converted in the converter unit 3 A power supply unit 5 and a DC voltage output from the power supply unit 5 to convert the power to a predetermined DC voltage (DC 5V microcomputer driving power supply, DC 12V load driving power supply) required for driving the air conditioner Controller 7 for initializing the air conditioner and determining the operating frequency of the compressor 11 according to the outdoor condition and the indoor unit to output the inverter driving signal, and the operating frequency determined by the controller 7. According to the drive signal output from the control unit 7 to rotate the compressor 11 according to the alternately turn-on or turn-off operation of the power transistor shown in the output from the converter unit 3 It is composed of the drive unit 9, which converts the DC power into three-phase AC power.

In the air conditioner for both heating and cooling as configured above, when the AC input power is supplied, the AC input power is converted into the DC power in the converter unit 3, and the converted DC power is input to the power supply unit 5 to provide air conditioning. It is converted into a microcomputer driving power supply of DC 5V and a load driving power supply of DC 12V necessary for driving of the machine, and is supplied to the control unit 7 and the inverter unit 11.

Therefore, the control unit 7 receives the DC voltage (microcomputer drive power) output from the power supply unit 5 to initialize the air conditioner.

At this time, when the user operates the key operation unit provided on the control panel of the remote controller or the indoor unit, inputs the desired operation mode and the set temperature, and turns on the operation key, the controller 7 controls the compressor according to the outdoor condition and the indoor unit. A driving frequency of 11) is determined and an inverter driving signal is output to the inverter unit 9.

Accordingly, the inverter unit 9 alternately turns on or off the six power transistors (not shown) according to the driving signal output from the control unit 7 to thereby output the DC power output from the converter unit 3 to 3. When converted into phase AC power and outputted, the compressor 11 is started by three-phase (u-phase, v-phase, w-phase) AC power output from the inverter unit 9.

That is, the inverter unit 9 supplies the operating frequency of the compressor 11 and the corresponding voltage to the compressor 11 in response to the cooling or heating capacity required for the operation of the air conditioner to supply the compressor 11 at a desired operating frequency. Drive it.

When the compressor 11 is driven, the refrigerant is heated at the time of heating, as shown by the dotted line (-) in FIG. 2, the compressor 11 → the four-way valve 15 → the indoor heat exchanger 17 → the expansion valve 19. ), Forming a refrigeration cycle circulated in the order of heating expansion valve (21) → outdoor heat exchanger (23) → four-way valve (15) → compressor (11).

On the other hand, during cooling, as the refrigerant is shown by the solid line (→) in FIG. 2, the compressor 11 → the four-way valve 15 → the outdoor heat exchanger 23 → the one-way valve 25 → the expansion valve 19 → A refrigeration cycle circulated in the order of an indoor heat exchanger (17) → a four-way valve (15) → a compressor (11) is formed.

There is no problem in the cooling operation according to the operation of the compressor 11, but in the case of heating operation, in particular, when the operation is started after leaving the air conditioner for a long time at a temperature below zero, the purpose of lubrication of the compressor 11 is achieved. There was a problem that the lubricating oil did not circulate the freezing cycle quickly so as not to properly lubricate the compressor 11 for a predetermined time.

Therefore, in the conventional air conditioner, as shown in FIG. 3, the band heater 12 for preheating the compressor 11 is fixed to the outer side of the lower side of the compressor 11, and the The thermostat 13 for controlling the power was fixed to the upper surface of the compressor 11 to control the power of the band heater 12 on / off according to a predetermined temperature.

By the way, in the conventional compressor 11 preheating system, when the power is always applied, and when the band heater 12 is normal, the compressor 11 is preheated, but it is left at a low temperature for a long time with the power off. When the temperature of the compressor 11 is lowered, when the compressor 11 is started at this time, the compressor 11 is not instantaneously preheated and is rotated to a low temperature state (about -5 ° C or less).

When the compressor 11 is rotated in a low temperature state, the lubricating oil inside the compressor 11 is separated from the refrigerant and is located at the upper end of the refrigerant. Therefore, the lubricating oil is discharged to the outside of the compressor 11 due to the structural characteristics of the compressor 11. (11) There was a problem that cylinder wear was large due to lack of lubrication of the cylinder.

Accordingly, the present invention has been made to solve the above problems, the power is not applied when operating the air conditioner after leaving the compressor for a long time at a low temperature below zero or less, or the compressor preheating is not enough due to the disconnection of the band heater. If there is a failure to protect the compressor operation by providing a waiting time to provide a compressor control device and method of the air conditioner to prevent the cylinder wear due to lack of lubrication.

In order to achieve the above object, a compressor control apparatus for an air conditioner according to the present invention includes a compressor for starting at an operating frequency determined according to outdoor conditions and an indoor unit, a band heater for preheating the compressor, and a power source of the band heater. An air conditioner having a thermostat for on / off control according to a predetermined temperature, comprising: compressor temperature sensing means for sensing the surface temperature of the compressor, outdoor temperature sensing means for sensing the outdoor temperature, and the compressor temperature sensing means. And a control means for waiting the start of the compressor according to the detected compressor surface temperature, and controlling the start waiting time of the compressor according to the outdoor temperature detected by the outdoor temperature sensing means.

In addition, the compressor control method of the air conditioner according to the present invention is a preheating step of preheating the inside and outside of the compressor to a predetermined temperature by controlling the power applied to the band heater while the thermostat is turned on / off according to the upper temperature of the compressor, Compressor temperature sensing step for detecting the surface temperature of the compressor, the start determination step for determining whether to start the compressor according to the compressor surface temperature detected in the compressor temperature sensing step, and the outdoor temperature for detecting the compressor start standby time A time setting step of setting a startup waiting time of the compressor according to an outdoor temperature sensing step, an outdoor temperature detected by the outdoor temperature sensing step, and starting the compressor when the compressor starting waiting time set in the time setting step has elapsed. Characterized in that the operation step of performing a heating operation.

1 is a compressor control block diagram of a conventional air conditioner;

2 is a cooling and heating cycle of a general air conditioner,

3 is a structural diagram of a conventional compressor;

4 is a structural diagram of a compressor according to the present invention;

5 is a control block diagram of a compressor control apparatus of an air conditioner according to an embodiment of the present invention;

6 is a driving circuit diagram of a compressor according to the present invention;

7 is a detailed circuit diagram of a compressor temperature sensing means applied to the present invention;

8A and 8B are flowcharts showing the operation sequence of the compressor control of the air conditioner according to the present invention.

Explanation of symbols for main parts of the drawings

30 converter means 31 compressor

32: band heater 33: thermostat

34: temperature sensor 35: power supply means

40 control means 45 inverter drive means

50: inverter means 55: compressor temperature detection means

60: outdoor temperature detection means

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 4, a band heater 32 for preheating the compressor 31 is provided outside the lower side of the compressor 31, and one upper surface of the compressor 31 is turned on / off according to a predetermined temperature. A thermostat 33 is attached to control the power applied to the band heater 32 to be turned off, and a temperature sensor 34 for sensing the upper surface temperature of the compressor 31 on the other upper surface of the compressor 31. ) Is attached.

On the other hand, reference numeral 29 is a connector for connecting the heater power.

A circuit block diagram for driving the compressor 31 configured as described above will be described with reference to FIG.

As shown in Figs. 5 to 7, the converter means 30 rectifies and smoothes the AC input power supplied from the AC power source 1 to convert it into DC power, and the power supply means 35 converts the converter means 30. SMPS (Switching Mode Power Supply) converts and outputs the DC power converted by the power supply to the predetermined DC voltage (DC 5V microcomputer driving power supply, DC 12V load driving power supply) required for driving the air conditioner.

The control unit 40 receives the DC voltage output from the power source unit 35 to initialize the air conditioner, and operates the optimum compressor 31 based on the outdoor unit and the frequency or indoor unit state instructing the indoor unit. A microcomputer that outputs an inverter drive PWM signal by determining a frequency, and the inverter drive means 45 from the control means 40 to rotate the compressor 31 in accordance with the operation frequency determined by the control means 40. This is a power-transistor driver circuit (PTR DRIVER) that amplifies the output PWM signals PWM1 to PWM6 as inverter drive signals.

In addition, the inverter means 50 alternately turns on or turns off the six power transistors TR1 to TR6 according to a drive signal output from the inverter driving means 45 and is output from the converter means 30. The DC power is converted into a three-phase (u-phase, v-phase, w-phase) AC power having a variable frequency and a variable voltage corresponding to the operating frequency of the compressor 31, and outputted to the compressor 31.

In addition, the compressor temperature sensing means 55 senses the upper surface temperature of the compressor 31 when the compressor 31 is started, and the compressor temperature sensing means 55 is shown in FIG. A temperature sensor 34 whose resistance value changes in accordance with the surface temperature of 31, a resistor R1 for dividing the resistance value changed by the temperature sensor 34, the temperature sensor 34 and a resistor R1; And a capacitor (C1) for filtering the noise component included in the voltage signal divided by the), the outdoor temperature detecting means 60 is a temperature sensor for detecting the outdoor temperature when the compressor (31) is started.

Hereinafter, the effect of the compressor control apparatus and method of the air conditioner configured as described above will be described.

8A and 8B are flowcharts showing the operation procedure of the compressor control of the air conditioner according to the present invention, in which S denotes a step (STEP) in FIGS. 8A and 8B.

First, when power is applied to the air conditioner, the AC input power supplied from the AC power source 1 is rectified and smoothed by the converter means 30 to convert into DC power, and the DC power converted by the converter means 30. Is converted into a microcomputer driving power supply of DC 5V and DC 12V load driving power required for driving the air conditioner and outputted to the control means 40 and the inverter driving means 45.

Therefore, in step S1, a DC voltage (microcomputer drive power source) output from the power source means 35 is received from the control means 40 to initialize the air conditioner.

When power is supplied to the air conditioner, the thermostat 33 mounted on the upper surface of the compressor 31 is turned on in step S2 when the temperature of the upper part of the compressor 31 is lower than a predetermined temperature, thereby turning on the band heater 32. Since the power is applied, the band heater 32 generates heat.

As the band heater 32 generates heat, the inside and outside of the compressor 31 are preheated to transfer heat to the upper portion. When the temperature of the upper portion of the compressor 31 is higher than a predetermined temperature by the transferred heat, the thermostat 33 is turned off. Since the power applied to the band heater 32 is cut off, the band heater 32 is turned off.

When the band heater 32 is turned off and the temperature of the upper part of the compressor 31 is lowered again, the thermostat 33 is turned on, and the operation of applying power to the band heater 32 is repeated. Since it is preheated to a constant temperature, the internal lubricating oil of the compressor 31 maintains a constant temperature and is kept mixed with the refrigerant.

At this time, when the user inputs the desired operation mode and the set temperature by operating the key operation unit provided on the control panel of the remote controller or the indoor unit, and turns on the operation key, it is determined in step S3 whether the start signal of the compressor 31 is input. When the compressor 31 start signal is not input (NO), the flow returns to step S2 and the operation of step S2 or less is repeated while preheating the compressor 31.

As a result of the discrimination in step S3, when the compressor 31 start signal is input (YES), the process proceeds to step S4 and the temperature sensor 34 detects a resistance value which changes according to the surface temperature of the compressor 31. .

The resistance value sensed by the temperature sensor 34 is divided by the resistor R1 and input to the input terminal A / D of the control means 40, and the control means 40 receives the input terminal A /. The analog data of the voltage input through D) is converted into digital to sense the surface temperature Tc of the compressor 31.

Therefore, in step S5, the surface temperature Tc of the compressor 31 sensed by the temperature sensor 34 is determined by the predetermined temperature T1 set in the control means 40; Or higher), and when the surface temperature Tc of the compressor 31 is lower than or equal to the predetermined temperature T1 (NO), the surface temperature Tc of the compressor 31 is maintained at a low temperature. Since the lubricating oil is separated from the refrigerant and positioned above the refrigerant, the flow proceeds to step S6 to detect the outdoor temperature To at the time when the compressor 31 is started by the outdoor temperature detecting means 60.

Accordingly, in step S7, it is determined whether the outdoor temperature To detected by the outdoor temperature detecting means 60 is equal to or greater than a predetermined temperature T2 (about -23 ° C.) set in the control means 40, and the outdoor temperature ( If To) is equal to or less than the predetermined temperature T2 (NO), the flow advances to step S8 to set the compressor 31 starting waiting time to 3 hours 30 minutes.

As a result of the discrimination in step S7, when the outdoor temperature To is equal to or higher than the predetermined temperature T2 (YES), the process proceeds to step S9, where the outdoor temperature To is set to the control means 40 by the predetermined temperature T3; -18 deg. C) or more, and when the outdoor temperature To is equal to or less than the predetermined temperature T3 (NO), the flow advances to step S10 to set the compressor 31 starting waiting time to 3 hours.

As a result of the determination in step S9, when the outdoor temperature To is equal to or higher than the predetermined temperature T3 (YES), the process proceeds to step S11, where the outdoor temperature To is set to the control means 40 by the predetermined temperature T4; -13 [deg.] C.) or more, and when the outdoor temperature To is equal to or less than the predetermined temperature T4 (NO), the flow advances to step S12 to set the compressor 31 starting waiting time to two hours.

As a result of the discrimination in step S11, when the outdoor temperature To is equal to or higher than the predetermined temperature T4 (YES), the flow advances to step S13, where the outdoor temperature To is set to the control means 40 by the predetermined temperature T5; -8 DEG C) or more, and when the outdoor temperature To is equal to or less than the predetermined temperature T5 (NO), the flow advances to step S14 to set the compressor 31 starting waiting time to 30 minutes.

As a result of the determination in step S13, when the outdoor temperature To is equal to or higher than the predetermined temperature T5 (YES), the process goes to step S15 and the compressor 31 starts waiting time is set to 40 minutes, and in step S16 the compressor ( 31) The start waiting time is counted by a timer built in the control means 40.

Therefore, in step S17, it is determined whether the countered waiting time has elapsed respectively according to the outdoor temperature To. If the waiting time has not elapsed (NO), the process returns to step S16 to start the compressor 31. The operation of step S16 or less is repeated while counting a waiting time continuously.

As a result of the discrimination in step S17, when the waiting time has elapsed (YES), it is determined that the compressor 31 is preheated, and the flow advances to step S18, whereby the control means 40 indicates the frequency of the outdoor unit and the indoor unit or the indoor unit. The inverter driving PWM signal is output to the inverter driving means 45 so as to rotate the compressor 31 by determining the operating frequency of the compressor 31 based on the state.

Accordingly, the inverter driving means 45 amplifies the PWM signal output from the control means 40 to alternately turn on or turn off the six power transistors TR1 to TR6 of the inverter means 50 to convert the converter. When the DC power output from the means 30 is converted into three-phase AC power and outputted, the compressor 31 is started by the three-phase (u-phase, v-phase, w-phase) AC power output from the inverter means 50. End the operation while performing the heating operation.

On the other hand, when the determination result in the step S5 indicates that the compressor 31 surface temperature Tc is higher than or equal to the predetermined temperature T1 (YES), the compressor 31 is not in a low temperature state, and thus the compressor (step S18) proceeds to the compressor ( Start operation 31) normally to finish heating operation.

According to the compressor control apparatus and method of the air conditioner according to the present invention as described above, when the air conditioner is operated after leaving the compressor at a low temperature below zero for a long time, power is not applied or disconnection of the band heater. Therefore, if the compressor is not preheated enough, there is an effect of preventing cylinder wear due to lack of lubrication because it protects the compressor operation by waiting time.

Claims (3)

An air conditioner having a compressor starting at an operating frequency determined according to outdoor conditions and an indoor unit, a band heater for preheating the compressor, and a thermostat for controlling the power supply of the band heater on / off according to a predetermined temperature. , Compressor temperature sensing means for sensing the surface temperature of the compressor; Outdoor temperature sensing means for detecting the outdoor temperature, And control means for waiting for the start of the compressor according to the compressor surface temperature sensed by the compressor temperature sensing means, and controlling the start waiting time of the compressor according to the outdoor temperature sensed by the outdoor temperature sensing means. Compressor control device of air conditioner. The method of claim 1, And the control means starts the compressor when the compressor surface temperature sensed by the compressor temperature sensing means is -5 ° C or higher. A preheating step of preheating the inside and outside of the compressor to a predetermined temperature by controlling the power applied to the band heater while the thermostat is turned on / off according to the upper temperature of the compressor, A compressor temperature sensing step of sensing a surface temperature of the compressor; A start discrimination step of determining whether to start the compressor or not according to the compressor surface temperature detected by the compressor temperature detection step; An outdoor temperature sensing step of detecting an outdoor temperature at the start of the compressor, A time setting step of setting a startup waiting time of the compressor according to the outdoor temperature detected by the outdoor temperature sensing step; And an operation step of starting the compressor to perform a heating operation when the compressor start waiting time set in the time setting step elapses.