KR100239532B1 - Compressor control apparatus and method for air conditioner - Google Patents

Abstract

The present invention relates to a compressor control apparatus and a method of an air conditioner, comprising a compressor for operating at an operating frequency determined according to outdoor conditions and instructions of an indoor unit, and an inverter means for switching to vary the operating frequency of the compressor. In the air conditioner, the carrier frequency range is set according to the cooling or heating operation mode at the start of the compressor, and the control unit is further provided to change the carrier frequency according to the change of the operating frequency of the compressor. The compressor is operated by differently setting the appropriate carrier frequency range according to the cooling or heating operation mode, and the compressor is driven at the optimum carrier frequency by varying the carrier frequency according to the change of the operating frequency of the compressor, thereby reducing the occurrence of leakage current.

Description

Compressor controller and method for air conditioner

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 an method of an air conditioner for reducing an increase in leakage current due to a carrier frequency of an inverter when a compressor is started.

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 for receiving power and converting it into a predetermined DC voltage required for driving the air conditioner (the microcomputer driving power supply of DC 5V and the load driving power supply of DC 12V) and the DC power output from the power supply unit 5; The controller 7 not only initializes the air conditioner by applying a voltage, but also determines an operating frequency of the compressor 11 according to outdoor conditions and instructions of an indoor unit, and outputs an inverter driving signal, and the operation determined by the controller 7. According to a drive signal output from the controller 7 to rotate the compressor 11 in accordance with the frequency, a power transistor, not shown, is alternately turned on or turned off and 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 configured as described above, when the AC input power is supplied, the AC input power is converted into the DC power from the converter unit 3, and the converted DC power is input to the power supply unit 5 to drive the air conditioner. Is converted into a microcomputer driving power supply of DC 5V and a load driving power supply of DC 12V and supplied to the control unit 7.

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 inputs the desired operation mode and set temperature by operating the key operation unit provided on the control panel of the remote controller or the indoor unit, and then turns on the operation key, the control unit 7 controls the carrier frequency for the operation of the compressor 11. (carrier frequency) is generated, and the driving frequency of the compressor 11 corresponding to the carrier frequency is determined according to the outdoor condition and the indoor unit's instructions, and the 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. At this time, even if the operating frequency of the compressor 11 rises (the compressor rotation speed increases), the carrier frequency is kept constant at 101 KHz, as shown in FIG.

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

In the conventional air conditioner, however, the carrier frequency controlled by the control unit 7 is constantly controlled from the start, as shown in FIG. 3, regardless of the operating frequency of the compressor 11. Since the high leakage current is generated at the start of the compressor 11 and, in particular, the number of times of switching of the power transistor occurs in the low operating frequency region, there is a problem that the leakage current increases in proportion to the increase in switching.

Accordingly, the present invention has been made to solve the above-mentioned problems, and operates the compressor by setting the appropriate carrier frequency range differently according to the cooling or heating operation mode at the time of startup of the compressor, according to the change in the operating frequency of the compressor It is an object of the present invention to provide a compressor control apparatus and a method of an air conditioner that reduces the generation of leakage current since the compressor is driven at an optimal carrier frequency by varying the carrier frequency.

In order to achieve the above object, a compressor control apparatus of an air conditioner according to the present invention includes a compressor for operating at an operating frequency determined according to outdoor conditions and an indoor unit, and an inverter means for switching to vary the operating frequency of the compressor. In the equipped air conditioner, the carrier frequency range is set according to the cooling or heating operation mode when the compressor is started, and further comprising a control means for varying the carrier frequency in accordance with the change in the operating frequency of the compressor. It is done.

In addition, the compressor control method of the air conditioner according to the present invention, the operation mode determination step of determining the cooling or heating operation mode of the air conditioner, and the carrier frequency in accordance with the cooling or heating operation mode determined in the operation mode determination step Compressor operation step of setting a region to operate the compressor, and a frequency variable step of switching the inverter means by varying the carrier frequency in accordance with the operating frequency changes during the operation of the compressor.

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

2 is a cooling / heating cycle diagram of a general air conditioner.

3 is a carrier frequency pattern diagram of a conventional compressor.

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

5 is a driving circuit diagram of a compressor applied to the present invention.

Figure 6 is a pattern of the carrier frequency according to the operating frequency of the compressor during the cooling operation of the present invention.

7 is a pattern of the carrier frequency according to the operating frequency of the compressor during the heating operation of the present invention.

8 is a flowchart showing an operation procedure of the compressor control of the air conditioner according to the present invention.

<Explanation of symbols for main parts of drawing>

15: converter means 20: power supply means

25 control means 26 control unit

27: inverter drive unit 30: inverter means

31 compressor 35 temperature sensing means

50: outdoor fan drive means 60: communication means

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

As shown in Figs. 4 and 5, the converter means 15 rectifies and smoothes the AC input power supplied from the AC power supply stage 1 to convert it into DC power, and the power supply means 20 converts the converter means 15 into the DC power supply. Is a SMPS (Switching Mode Power Supply) which converts and outputs a DC power converted by the &lt; RTI ID = 0.0 &gt; 1) &lt; / RTI &gt;

The control unit 25 receives the DC voltage output from the power supply unit 20 to initialize the air conditioner, and determines the operation frequency of the compressor 31 according to the outdoor condition and the indoor unit to determine the inverter driving signal. As a microcomputer for outputting, the control means 25 determines the optimum compressor 31 operating frequency based on the outdoor unit situation and the frequency or indoor unit state indicated by the indoor unit, and outputs inverter drive PWM signals PWM1 to PWMM6. And a power-transistor driver circuit which amplifies the PWM signal output from the controller 26 into an inverter driving signal so as to rotate the compressor 31 according to the operating frequency determined by the controller 26. The inverter drive part 27 is comprised.

In addition, the inverter means 30 alternately turns on or turns off the six power transistors TR1 to TR6 in accordance with a drive signal output from the inverter driver 27 of the control means 25 to convert the converter means ( 15 is converted into a three-phase (u-phase, v-phase, w-phase) AC power of a variable frequency and a variable voltage corresponding to the operating frequency of the compressor 31 and supplied to the compressor 31, The temperature sensing means 35 is a thermistor for sensing the outdoor temperature, the discharge part temperature of the compressor 31, and the temperature of the outdoor heat exchanger 23.

The outdoor fan driving means 50 receives the control signal output from the control means 25 to control the outdoor fan on / off, as well as to control the speed (speed), and the communication means 60 is connected to the indoor unit. It is a communication cable that transmits and receives data with each other during outdoor period.

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

FIG. 8 is a flowchart showing a compressor control operation procedure of the air conditioner according to the present invention, in which S denotes a step.

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 15 to convert into DC power, and the DC power converted by the converter means 15. Is converted into a microcomputer driving power supply of DC 5V and a DC 12V load driving power required for driving the air conditioner and outputted to the control means 25 and the inverter driver 27.

Therefore, in step S1, the DC conditioner (microcomputer drive power supply) output from the power supply means 20 is received by the control means 25 to initialize the air conditioner.

At this time, if the user inputs the desired operation mode (cooling or heating) by operating the key operation unit provided on the control panel of the remote controller or the indoor unit, and then turns on the operation key, it is determined whether the operation condition of the compressor 31 is in step S2. When the compressor 31 is not in the operating condition (NO), the operation of step S2 or less is repeated while the air conditioner is kept in the operating standby state.

As a result of the discrimination in step S2, in the case of the operating condition of the compressor 31 (YES), the flow goes to step S3, and the control means 25 determines the compressor ( The operating frequency of 31 is determined by the control unit 26 and outputs an inverter driving PWM signal to the inverter driving unit 27 to rotate the compressor 31.

Accordingly, the inverter driver 27 amplifies the PWM signal output from the controller 26 and outputs an inverter driving signal for controlling the switching frequency of the inverter means 30.

At this time, in step S4, the control means 25 determines whether the operation mode of the air conditioner is cooling, and in the case of the cooling mode (YES), proceeds to step S5 while determining the optimum carrier frequency suitable for the cooling mode. In the means 30, the six power transistors TR1 to TR6 are alternately turned on or off in accordance with the drive signal output from the inverter driver 27 so that the DC power output from the converter means 15 can be adjusted to the desired frequency. When converted into three-phase AC power and outputted, the compressor 31 is driven by three-phase (u-phase, v-phase, w-phase) AC power output from the inverter means 30.

When the compressor 31 is operated, at step S6, the operation frequency of the compressor 31 is checked to determine whether it is 30 Hz or less. If it is 30 Hz or less (YES), the process proceeds to step S61 to show the carrier frequency fc. As shown in the figure, switching to 1100 Hz is made.

As a result of the determination in step S6, if it is not less than 30Hz (NO), the process proceeds to step S7 to determine whether the operating frequency of the compressor 31 is increased to 51Hz or less than 30Hz, and is less than 51Hz (YES). In step S71, the carrier frequency fc is lowered to 800 Hz as shown in Fig. 6, and operation is performed.

As a result of the determination in step S7, if it is not less than 51 Hz (NO), the process proceeds to step S8 to determine whether the operating frequency of the compressor 31 is increased to 65 Hz or less than 51 Hz, and if it is 65 Hz or less (YES). In step S81, the carrier frequency fc is increased to 900 Hz to operate as shown in FIG.

As a result of the discrimination in step S8, when the frequency is not less than 65 Hz (NO), the operating frequency of the compressor 31 is increased to be 65 Hz or more, and the flow proceeds to step S9 to show the carrier frequency fc as shown in FIG. While increasing to 1100 Hz, the process returns to the step S4 to repeat the operation of the step S4 or less.

On the other hand, when the determination result in the step S4, in the heating mode (NO), proceed to step S10 while determining the optimal carrier frequency suitable for the heating mode, the drive output from the inverter drive unit 27 in the inverter means (30) When the six power transistors TR1 to TR6 are alternately turned on or off in accordance with the signal to convert the DC power output from the converter means 15 into a three-phase AC power source having a desired frequency, the inverter means 30 The compressor 31 is operated by three-phase (u-phase, v-phase, w-phase) AC power output from

When the compressor 31 is operated, in step S11, the operation frequency of the compressor 31 is checked to determine whether it is 30 Hz or less. If it is 30 Hz or less (YES), the process proceeds to step S111 and the carrier frequency fc is shown in FIG. As shown in the figure, switching to 1100 Hz is made.

As a result of the determination in step S11, if it is not less than 30Hz (NO), the process proceeds to step S12 to determine whether the operating frequency of the compressor 31 is increased to 51Hz or less than 30Hz, and if it is 51Hz or less (YES). In step S121, the carrier frequency fc is reduced to 700 Hz to operate as shown in FIG.

If the determination result in step S12 is not 51 Hz or less (NO), the process proceeds to step S13 to determine whether the operating frequency of the compressor 31 is increased to 65 Hz or less than 5 Hz and is 65 Hz or less (YES). In step S131, the carrier frequency fc is increased to 800 Hz to operate as shown in FIG.

As a result of the discrimination in step S13, if it is not less than 65 Hz (NO), the operating frequency of the compressor 31 is increased to be 65 Hz or more, so the flow advances to step S14 to show the carrier frequency fc as shown in FIG. While increasing to 1100 Hz, the process returns to the step S4 to repeat the operation of the step S4 or less.

According to the compressor control apparatus and method of the air conditioner according to the present invention as described above, the compressor is operated by differently setting the appropriate carrier frequency range in accordance with the cooling or heating operation mode at the start of the compressor, The carrier frequency is varied according to the change of operating frequency to drive the compressor at the optimum carrier frequency, thereby reducing the leakage current.

Claims (2)

An air conditioner having a compressor for operating at an operating frequency determined according to outdoor conditions and an indoor unit and an inverter means for switching the operating frequency of the compressor to be variable, the air conditioner being adapted to a cooling or heating operation mode when the compressor is started. And a control means for setting a carrier frequency range and for varying the carrier frequency in accordance with a change in operating frequency of the compressor. An operation mode discrimination step for determining a cooling or heating operation mode of an air conditioner, a compressor operation step for operating a compressor by setting a carrier frequency region in accordance with the cooling or heating operation mode determined in the operation mode discrimination step, and the compressor Compressor control method of an air conditioner, characterized in that consisting of a frequency variable step of switching the inverter means by varying the carrier frequency in accordance with the operating frequency changes during operation of.

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