KR100321244B1 - Harmonic Suppression Device of Air Conditioner and Its Suppression Method - Google Patents

Abstract

The present invention relates to a harmonic suppression apparatus of the air conditioner and a suppression method thereof, comprising: converter means for converting an AC input power source of a power input stage into a DC power source; and a three-phase AC power source having a desired frequency for the DC power converted by the converter means. An air conditioner comprising: an inverter means for converting the voltage into an inverter; and a compressor rotating by a three-phase alternating current power output from the inverter means, the air conditioner detecting means for detecting a zero potential point of an input voltage input from the power input terminal; An outdoor temperature sensing means for sensing an outdoor temperature, a control means for determining whether the outdoor temperature sensed by the outdoor temperature sensing means is an overload or a normal load condition and increasing harmonic suppression time than the normal load condition if the overload condition; The compressor in synchronization with the zero potential point of the input voltage input from the zero potential detecting means. It is composed of harmonic suppression means that short-circuits power line, and it detects outdoor temperature to determine whether it is an overload condition.In case of overload, it increases harmonic suppression time more effectively than normal load and effectively suppresses harmonic components. It can satisfy the criteria of limiting standard (EN55022).

Description

Harmonic Suppression Device of Air Conditioner and Its Suppression Method

The present invention relates to an inverter air conditioner that varies the operating frequency of a compressor according to cooling or heating capacity, and in particular, a harmonic suppression apparatus of an air conditioner that effectively removes harmonic components generated during overload operation of an air conditioner, and a suppression method thereof. It is about.

In general, as shown in FIG. 1, the inverter device includes a converter unit 3 for converting AC input power input from the power input terminal 1 into DC power, and a compressor 9 according to outdoor conditions and instructions of an indoor unit. The controller 5 outputs an inverter driving signal by determining an operating frequency of the controller, and the driving signal output from the controller 5 to rotate the compressor 9 according to the operating frequency determined by the controller 5. It consists of an inverter section 7 which alternately turns on or off the power-transistor, not shown, to convert the DC power output from the converter section 3 into three-phase AC power.

The converter unit 3 filters the ripple component included in the bridge rectifier 11 for full-wave rectifying the AC input power at a predetermined DC voltage, and the ripple component included in the DC voltage full-wave rectified by the bridge rectifier 11. And a smoothing capacitor C1 connected to the output terminal of the bridge rectifier 11 to charge the full-wave rectified DC voltage.

In the inverter device configured as described above, when AC input power is applied from the power input terminal 1, the AC input power is rectified to a predetermined DC power through the bridge rectifier 11 of the converter unit 3, and the bridge rectifier ( The ripple component included in the DC power source rectified by 11) is filtered through the smoothing capacitor C1.

In this case, the inverter unit 7 alternately turns on or off the six power transistors (not shown) according to the driving signal output from the controller 5 to generate three-phase DC power output from the converter unit 3. u-phase, v-phase, w-phase) The compressor 9 is driven by switching to AC power.

As described above, the converter unit 3 for converting the AC input power to the DC power source uses a relatively large capacity smoothing capacitor C1 to obtain DC having a small ripple, but the input current is affected by the smoothing capacitor C1. Is distorted into non-sinusoidal waveforms, which leads to an increase in power harmonics, which causes an increase in reactive power, an operation failure of a power capacitor, and a breaker.

Therefore, in Europe and other countries, the Harmonic Power Harmonic Standard (EN55022) has been enacted through the International Electronical Commission (IEC) to prevent the export of products that do not satisfy these requirements. .

Therefore, the design of the air conditioner should be designed to satisfy the harmonic standard (EN55022). Especially, when the inverter unit 7 switches to drive the compressor 9, the harmonic component is significantly increased. Harmonic suppressors have been developed and used for suppression.

As shown in FIG. 2, the conventional harmonic suppressing apparatus of the conventional air conditioner includes a zero potential detecting unit 13 and a harmonic suppressing unit 15 in a general inverter device.

The zero potential detection unit 13 detects a zero potential point of the AC input voltage input from the power input terminal 1 and inputs a pulse signal to the controller 3 at the zero potential point, and the harmonic suppressing unit 15 receives the zero potential point. On the falling edge of the pulse signal input from the upper sensing unit 13, the + power line and the-power line connecting the converter unit 3 and the inverter unit 7 are short-circuited during the harmonic suppression time set in the controller 3. Current to flow.

In the harmonic suppression apparatus of the air conditioner configured as described above, when AC input power is applied from the power input terminal 1, the AC input power is converted into DC power through the converter unit 3, and the inverter unit 7 In accordance with the drive signal output from the control section 5, six power-transistors (not shown) are alternately turned on or off to operate the DC power output from the converter section 3 in three phases (u phase, v phase, w phase). The compressor 9 is driven by converting into AC power.

When the compressor 9 is driven, the current waveform b falls behind the voltage in proportion to the current consumption of the load (compressor). As shown in FIG. 4, the current waveform b and the voltage waveform a The phase difference of is generated and the harmonic component increases.

Therefore, in order to remove the harmonic components, the zero potential point of the AC input voltage input from the power input terminal 1 is detected by the zero potential sensing unit 13, and as shown in FIG. 3, the voltage waveform a is zero. The pulse signal c is inputted to the control part 5 when it is a point.

The control unit 5 drives the harmonic suppressing unit 15 for a predetermined harmonic suppression time at the falling edge of the pulse signal c input from the zero potential detecting unit 13 to convert the converter unit 3 and the inverter unit 7. Since the + power supply line and-power supply line are connected to each other, the current waveform is arbitrarily created in a short time, and as shown in FIG. 5, the phase difference between the current waveform (b) and the voltage waveform (a) is reduced, thereby suppressing harmonic components. Done.

On the other hand, when the compressor 9 is operated at a low operating frequency, the current consumption is also low, so the phase difference between the voltage waveform a and the current waveform b is small, and when the compressor 9 is operated at a high operating frequency, the current consumption is also high. Since the phase difference between the voltage waveform a and the current waveform b increases, the control section 5 sets the harmonic suppression time in proportion to the operating frequency of the compressor 9.

Accordingly, the harmonic suppression unit 15 is turned off when the harmonic suppression time set in the control unit 5 according to the operating frequency of the compressor 9 elapses.

By the way, in such a conventional harmonic suppression apparatus, even when the compressor 9 is operated at the same operating frequency, as shown in Fig. 6, the phase difference between the voltage waveform a and the current waveform b 'at the time of overload is normal. Since the harmonic suppression unit 15 is driven during the harmonic suppression time set in proportion to the operating frequency of the compressor 9 without considering the phase difference between the voltage waveform (a) and the current waveform (b) below, There is a problem that does not effectively suppress harmonic components.

Therefore, the present invention was devised to solve the above-mentioned problems, and it is determined whether the overload condition by sensing the outdoor temperature, and when the overload increases the harmonic suppression time to suppress the harmonic components more effectively than the normal load, the load fluctuations It is an object of the present invention to provide a harmonic suppression apparatus and an suppression method of an air conditioner capable of satisfying the criteria of the specification (EN55022) that limits the harmonic current regardless.

Harmonic suppression apparatus of the air conditioner according to the present invention for achieving the above object, the converter means for converting the AC input power of the power input terminal into a DC power source, and the three-phase AC of the desired frequency to the DC power converted by the converter means An air conditioner having an inverter means for converting into a power source and a compressor rotating by a three-phase AC power output from the inverter means, comprising: a zero potential detecting means for detecting a zero potential point of an input voltage input from the power input terminal; An outdoor temperature sensing means for sensing an outdoor temperature, a control means for determining whether the outdoor temperature sensed by the outdoor temperature sensing means is an overload or a normal load condition and increasing the harmonic suppression time than the normal load condition if it is an overload condition; In synchronization with the zero potential point of the input voltage input from the zero potential detecting means; Characterized in that the harmonic suppressing means for shorting the power line of the compressor.

In addition, the harmonic suppression method of the air conditioner according to the present invention, in the air conditioner for operating the compressor by converting the AC power at the power input terminal to a direct current, converting the converted DC power to a three-phase AC power of the desired frequency A time setting step of setting a driving time of the harmonic suppressing means proportional to an operating frequency of the compressor, a zero potential sensing step of detecting a zero potential point of an input voltage input from the power input terminal, and an outdoor temperature by sensing an outdoor temperature An overload judging step for determining whether is an overload or normal load condition, and an overload for shorting the power supply line of the compressor for an increased time period than the driving time of the harmonic suppressing means set in the time setting step if the overload condition occurs in the overload judging step. Harmonic suppression step and the time setting stage if the normal load condition in the overload determination step During the driving time of the harmonic suppression means is set at the top you like to short circuit the power supply line of the compressor is characterized in that consisting of a harmonic suppression stage.

1 is a circuit diagram of a typical inverter device;

2 is a block diagram of a conventional harmonic suppression apparatus;

3 is a pulse waveform diagram output from the zero potential point of the input power supply voltage,

4 is a waveform diagram of voltage and current before driving the harmonic suppressing unit of FIG. 2;

5 is a waveform diagram of voltage and current when the harmonic suppressing unit of FIG. 2 is driven;

6 is a voltage and current waveform diagram of a conventional overload and normal load,

7 is a block diagram of a harmonic suppressing apparatus of an air conditioner according to an embodiment of the present invention;

8 is a detailed circuit diagram of a harmonic suppressing apparatus of an air conditioner according to an embodiment of the present invention;

9 is a flowchart showing a harmonic suppression operation procedure of the air conditioner according to the present invention;

10 is a voltage and current waveform diagram of overload and normal load according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100: converter means 110: zero potential detection means

120: outdoor temperature detection means 130: control means

140: harmonic suppressing means 150: inverter means

160: Compressor

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

7 is a block diagram of a harmonic suppression apparatus of an air conditioner according to an embodiment of the present invention, and FIG. 8 is a detailed circuit diagram of a harmonic suppression apparatus of an air conditioner according to an embodiment of the present invention.

As shown in FIG. 7 and FIG. 8, the converter means 100 rectifies and smoothes the AC input power input from the power input terminal 1 to the DC power, and the zero potential detecting means 110 is the power input terminal. Detecting the zero potential point of the AC input power input from (1), the zero potential detection means 110 is the filter unit 112, photocoupler 114, the first switching unit 116 and the second switching unit It consists of 118.

The filter unit 112 is composed of resistors R1 and R2 and capacitors C1 and C2 to remove power noise components of AC input power input from the power input terminal 1, and the photocoupler 114 is The filter unit 112 receives the AC input power from which the power noise is removed and operates on at the zero potential point of the AC input voltage.

The first switching unit 116 is composed of a resistor (R3 ~ R6), a transistor (TR1) and a capacitor (C3) to turn on by receiving a voltage (Vcc1) applied from the outside when the photocoupler 114 is turned on. The second switching unit 118 receives the voltage Vcc1 applied from the outside during the turn-on operation of the first switching unit 116 to turn on the resistors R7 to R10, the transistor TR2, and the capacitor. It consists of (C4).

In addition, the outdoor temperature detecting means 120 detects an outdoor temperature that changes during the operation of the air conditioner, and the outdoor temperature detecting means 120 changes the resistance value according to the outdoor temperature. ) And a resistor R15 for dividing the resistance value changed by the outdoor temperature sensor 122, and filtering noise components included in the voltage signal divided by the outdoor temperature sensor 122 and the resistor R15. The capacitor C9 and a resistor R16 for inputting a voltage signal from which the noise component is filtered by the capacitor C9 to the control means described later.

In addition, the control means 130 is a phase of the input current input from the power input terminal 1 in synchronization with the zero potential point signal (pulse signal) of the AC input voltage input from the zero potential detecting means 110 As a microcomputer that outputs a control signal to approach a phase, and outputs an inverter drive signal by determining an operating frequency of the compressor 160 according to outdoor conditions and instructions of an indoor unit, the control means 130 is the compressor 160. And stores the basic control value (harmonic suppression time) which changes in proportion to the operating frequency of the ROM table on the ROM table, and determines whether the outdoor temperature detected by the outdoor temperature detecting means 120 is an overload condition or a normal load condition. To variably control the harmonic suppression time stored on the ROM table.

In addition, the harmonic suppressing means 140 receives the switching signal output from the control means 130 to suppress the harmonic components by bringing the phase of the input current closer to the phase of the input voltage. Is composed of a third switching unit 142, a hybrid integrated circuit device 144 (hereinafter referred to as a hybrid device), and a power switching unit 146.

The third switching unit 142 is a capacitor (C5 ~ C8) to supply a current to the hybrid element 144 according to a high level control signal output from the control means 140. Comprising resistors R11 to R13, transistor TR3, and diode D1, the hybrid element 144 receives a current from the third switching unit 142 and outputs a high level voltage signal.

The power switching unit 146 short-circuits the + power line and the -power line that connects the converter means 100 and the inverter means to be described later according to a high level voltage signal input from the hybrid element 144, and current flows. And a resistor R14, a transistor TR4, a diode D2, and choke transformers L1 and L2 for removing power supply noise.

In addition, in the drawing, the inverter means 150 alternately turns on or off the six power-transistors (not shown) according to the driving signal output from the control means 130 and is output from the converter means 100. 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 operation frequency of the compressor 160, and is supplied to the compressor 160.

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

When AC input power is applied from the power input terminal 1, the AC input power is converted into DC power through the converter means 100, and the inverter means 150 is not shown in accordance with the drive signal output from the control means 130. The six power transistors are alternately turned on or off to convert the DC power output from the converter means 100 into three-phase (u-phase, v-phase, w-phase) AC power to drive the compressor 160. .

When the compressor 160 is driven, the current waveform b lags behind the voltage in proportion to the current consumption of the load (compressor). As shown in FIG. 4, the current waveform b and the voltage waveform a The phase difference of is generated and the harmonic component increases.

Accordingly, in the present invention, the zero potential detecting means 100, the outdoor temperature detecting means 120, the control means 130 and the harmonic suppressing means 140 are constituted so that the phase of the current is close to the phase of the voltage. As you do, control.

FIG. 9 is a flowchart showing the harmonic suppression operation procedure of the air conditioner according to the present invention, in which S denotes a step.

First, in step S1, the control means 130 displays the basic data (driving time) of the harmonic suppressing means 140 for increasing or decreasing the harmonic suppressing time t according to the operating frequency of the compressor 160 on the ROM table. Set it.

The basic data value of the harmonic suppressing means 140 is that when the operating frequency of the compressor 160 decreases, the current consumption is also lowered, so that the phase difference between the voltage waveform and the current waveform becomes smaller, so that the driving time of the harmonic suppressing means 140 is shortened. As the operating frequency of 160 increases, the current consumption increases, and the phase difference between the voltage waveform and the current waveform increases, so that the driving time of the harmonic suppressing means 140 is lengthened to control the harmonic suppression time t.

Subsequently, in step S2, the control means 130 determines the operating frequency of the compressor 160 according to the outdoor condition and the instruction of the indoor unit.

When the power noise component of the AC input power input from the power input terminal 1 is removed through the filter unit 112 and applied to the photo coupler 114 of the zero potential detecting unit 110, the photo coupler 114 is applied. It operates on at the zero potential of the AC input voltage.

When the photocoupler 114 is turned on, the transistors TR1 and TR2 of the first and second switching units 116 and 118 are turned on to synchronize the zero potential point of the AC input voltage from the zero potential detecting means 110. The pulse signal c is input to the control means 130, as shown in FIG.

Therefore, in step S3, it is determined whether the zero potential pulse signal c has been inputted to the control means 130, and the zero potential pulse signal c when the zero potential pulse signal c is not input (NO). The operation of step S3 or less is repeated until) is input.

As a result of the discrimination in step S3, when the zero potential pulse signal c is input (YES), the process proceeds to step S4 and the outdoor temperature sensor 122 detects a resistance value that changes according to the outdoor temperature. The resistance value sensed by the temperature sensor 122 is divided by the resistor R15 and input to the control means 130.

Accordingly, in step S5, the control means 130 converts the analog data of the voltage input from the outdoor temperature sensing means 120 into digital to determine whether the outdoor temperature is an overload or normal load condition.

The overload or normal load condition is appropriately determined according to the type of the air conditioner and the installation position of the air conditioner. For example, in the case of cooling operation, if the outdoor temperature is 40 ° C. or more, the overload condition is determined. Judging by normal load conditions.

Moreover, overload conditions can be subdivided as needed. For example, at the time of cooling operation, 40 degreeC-450 degreeC is subdivided into a 1st overload condition and 45 degreeC or more into a 2nd overload condition.

As a result of the discrimination in step S5, if the outdoor temperature is an overload condition (YES), the control means 130 proceeds to step S6 and the control means 130 sets the basic data value of the harmonic suppressing means 140 set on the ROM table in step S1. In t), the driving time of the harmonic suppressing means 140 is increased by? t, that is, as the current consumption increases.

On the other hand, if the determination result in step S5 indicates that the outdoor temperature is a normal load condition (NO), the process proceeds to step S7 and the control means 130 corresponds to the operating frequency of the compressor 160 from the ROM table set in step S1. The driving time t of the harmonic suppressing means 140 is determined.

As described above, when it is determined whether the overload or the normal load condition according to the outdoor temperature determines the driving time of the harmonic suppressing means 140, the control means 130 is inputted from the zero potential detecting means 110 to step S8 The high level control signal for driving the harmonic suppression means 140 is output to the harmonic suppression means 140 during the harmonic suppression time determined according to the outdoor temperature at the falling edge of the pulse signal c.

Accordingly, in the harmonic suppressing means 140, the transistor TR3 of the third switching unit 142 is turned on according to a high level control signal output from the control means 130 to supply current to the hybrid element 144. Therefore, the + power line and the-power line connecting the converter means 100 and the inverter means 150 are shorted.

When the + power supply line and the-power supply line are short-circuited, a current waveform is arbitrarily made in a short time, so that the phase difference between the current waveform b and the voltage waveform a becomes small to suppress harmonic components as shown in FIG. 10. Done.

At the same time, even when the compressor 160 is operated at the same operating frequency, the phase difference between the voltage waveform (a) and the current waveform (b ') under overload becomes larger than the phase difference between the voltage waveform (a) and the current waveform (b) under normal load. In consideration of the above, the harmonic suppression time is increased during an overload condition to reduce the phase difference between the voltage waveform (a) and the current waveform (b ') even under overload.

Therefore, it effectively suppresses harmonic components regardless of load fluctuations, so that the control operation that satisfies the current harmonic regulation of EN55022 can be made possible and can be used for harmonic devices in all electronic devices using the inverter method.

As described above, according to the harmonic suppression apparatus and method of the air conditioner according to the present invention, the outdoor temperature is sensed to determine whether it is an overload condition. The effective suppression has the effect of satisfying the standard of EN55022, which limits the harmonic current regardless of load variation.

Claims (6)

Converter means for converting AC input power at the power input stage into DC power, inverter means for converting the DC power converted by the converter means into three-phase AC power of a desired frequency, and three-phase AC power output from the inverter means. In an air conditioner having a compressor that rotates by Zero potential detecting means for detecting a zero potential point of an input voltage input from the power input terminal; Outdoor temperature sensing means for detecting the outdoor temperature, A control means for determining whether the outdoor temperature sensed by the outdoor temperature sensing means is an overload or a normal load condition and increasing the harmonic suppression time than the normal load condition if the overload condition; Harmonic suppression apparatus of the air conditioner, characterized in that the harmonic suppressing means for shorting the power supply line of the compressor in synchronization with the zero potential point of the input voltage input from the zero potential detecting means. The method of claim 1, And the harmonic suppressing means short-circuits the + power line and the -power line connecting the converter means and the inverter means during the harmonic suppression time determined by the control means. The method according to claim 1 or 2, The control means stores a basic control value for proportionally controlling the driving time of the harmonic suppressing means according to the operating frequency of the compressor, and changing the basic control value according to the outdoor temperature detected by the outdoor temperature sensing means. Harmonic suppression apparatus of the air conditioner characterized in that. Converter means for converting AC input power at the power input stage into DC power, inverter means for converting the DC power converted by the converter means into three-phase AC power of a desired frequency, and three-phase AC power output from the inverter means. In an air conditioner having a compressor that rotates by An apparatus for suppressing harmonic components by reducing a phase difference between an input current and an input voltage includes: zero potential sensing means for sensing a zero potential point of an input voltage input from the power input terminal, outdoor temperature sensing means for sensing an outdoor temperature, and Control means for outputting a control signal for bringing the phase of the input current closer to the phase of the input voltage in synchronization with the zero potential point of the input voltage input from the zero potential detecting means, and the input current according to the control signal output from the control means. And a harmonic suppressing means for shorting the power supply line of the compressor so that the phase of the phase approaches the phase of the input voltage. The control means determines whether the outdoor temperature sensed by the outdoor temperature sensing means is an overload or a normal load condition, and if the overload condition increases the driving time of the harmonic suppressing means than the normal load condition. Harmonic Suppressor. In the air conditioner for operating the compressor by converting the AC power at the power input stage to DC, and converting the converted DC power to a three-phase AC power of the desired frequency, A time setting step of setting a driving time of the harmonic suppressing means proportional to an operating frequency of the compressor; A zero potential sensing step of detecting a zero potential point of an input voltage input from the power input terminal; An overload determination step of detecting the outdoor temperature to determine whether the outdoor temperature is an overload or normal load condition; An overload harmonic suppression step of shorting the power supply line of the compressor for an increased time than the driving time of the harmonic suppression means set in the time setting step if the overload condition is in the overload determination step; And a harmonic suppression step of a normal load at the time of normal load condition that short-circuits the power supply line of the compressor during the driving time of the harmonic suppression means set in the time setting step if the normal load condition in the overload discrimination step. The method of claim 5, The harmonic suppression step of the overload and the normal load is a harmonic suppression method of the air conditioner, characterized in that for shorting the power supply line of the compressor in synchronization with the zero potential point of the input voltage detected in the zero potential detection step.