KR20100003580A - Motor controller of air conditioner - Google Patents

Motor controller of air conditioner Download PDF

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Publication number
KR20100003580A
KR20100003580A KR1020080063551A KR20080063551A KR20100003580A KR 20100003580 A KR20100003580 A KR 20100003580A KR 1020080063551 A KR1020080063551 A KR 1020080063551A KR 20080063551 A KR20080063551 A KR 20080063551A KR 20100003580 A KR20100003580 A KR 20100003580A
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KR
South Korea
Prior art keywords
inverter
converter
power
command value
switching
Prior art date
Application number
KR1020080063551A
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Korean (ko)
Inventor
김광만
Original Assignee
엘지전자 주식회사
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Publication date
Application filed by 엘지전자 주식회사 filed Critical 엘지전자 주식회사
Priority to KR1020080063551A priority Critical patent/KR20100003580A/en
Publication of KR20100003580A publication Critical patent/KR20100003580A/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F25B49/025—Motor control arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/021—Inverters therefor

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Inverter Devices (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

PURPOSE: A motor control device for an air-conditioner is provided to guarantee the stability of the converter device by connecting the first and the second converters in parallel and reducing the current flowing in the converter. CONSTITUTION: A motor control device(200) for an air-conditioner comprises first and second inverters(220,225). The inverter converts inputted DC power into AC power through switching and drives a motor(250). The second inverter connects to the first inverter in parallel. The second inverter converts the DC power into the AC power through switching, so as to drive the motor.

Description

Motor controller of air conditioner {Motor controller of air conditioner}

The present invention relates to an electric motor control apparatus of an air conditioner, and more particularly, to an electric motor control apparatus of an air conditioner capable of ensuring the safety of circuit elements in the control apparatus.

An air conditioner is a device that is disposed in a room, a living room, an office, or a business store to adjust a temperature, humidity, cleanliness, and airflow of an air to maintain a comfortable indoor environment.

Air conditioners are generally divided into one-piece and separate types. The integrated type and the separate type are functionally the same, but the integrated type integrates the functions of cooling and heat dissipation to install a hole in the wall of the house or hang the device on the window, and the separate type installs an indoor unit that performs cooling / heating on the indoor side and outdoor. On the side, an outdoor unit that performs heat dissipation and compression functions was installed, and two separate devices were connected by refrigerant pipes.

In the air conditioner, an electric motor is used for a compressor, a fan, and the like, and an electric motor control device for driving the air conditioner is used. The motor controller of the air conditioner receives a commercial AC power and converts it into a DC voltage, converts the DC voltage into a commercial AC power with a predetermined frequency, and supplies the motor to the motor to control a motor such as a compressor or a fan.

On the other hand, the motor control apparatus of the air conditioner drives the motor using a high voltage and a high current, thereby increasing the possibility of damage to most circuit elements in the motor control apparatus, various methods have been proposed to protect this.

An object of the present invention is to provide an electric motor control apparatus for an air conditioner that can ensure the safety of circuit elements in the control apparatus.

The motor control apparatus of the air conditioner according to the embodiment of the present invention for solving the above-mentioned problems and other problems, the first inverter for converting the input DC power to AC power by switching operation to drive the motor; And a second inverter connected in parallel to the first inverter and converting the DC power into AC power by a switching operation to drive the motor.

The motor control apparatus of the air conditioner according to the embodiment of the present invention for solving the above-mentioned problems and other problems, the first converter for converting the commercial AC power input to the DC power by a switching operation, and the first converter And a second converter connected in parallel to the commercial AC power and converting the commercial AC power into DC power by a switching operation.

As described above, the motor control apparatus of the air conditioner according to the embodiment of the present invention can reduce the current flowing through each inverter by connecting the first inverter and the second inverter in parallel, so that the stability of the inverter element is, of course, Therefore, it is possible to ensure the safety of the entire circuit elements in the control device. Furthermore, a relatively inexpensive inverter can be used, thereby reducing manufacturing costs.

In addition, when converting to a DC power source using a three-phase AC power supply, by connecting the first converter and the second converter in parallel, the current flowing through each converter can be reduced, so that not only the stability of the converter element but also the control device It is possible to ensure the safety of the entire circuit elements. In addition, manufacturing cost is reduced.

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

1 is a schematic diagram of an air conditioner according to the present invention.

Referring to the drawings, the air conditioner 40 is largely divided into an indoor unit (I) and an outdoor unit (O).

The outdoor unit O includes a compressor 2 serving to compress the refrigerant, a compressor electric motor 2b for driving the compressor, an outdoor side heat exchanger 4 serving to radiate the compressed refrigerant, and an outdoor unit. An outdoor blower 4 disposed on one side of the heat exchanger 4 and including an outdoor fan 4a for promoting heat dissipation of the refrigerant and an electric motor 4b for rotating the outdoor fan 4a, and an expansion for expanding the condensed refrigerant; A mechanism (4), a cooling / heating switching valve (10) for changing the flow path of the compressed refrigerant, and an accumulator (4) for temporarily storing gasified refrigerant to remove moisture and foreign matter and then supplying a refrigerant of a constant pressure to the compressor. And the like.

The indoor unit (I) is disposed in the room to perform the cooling / heating function of the indoor side heat exchanger (5), and the indoor fan (9a) and the room arranged on one side of the indoor side heat exchanger (5) to promote heat dissipation of the refrigerant. And an indoor blower 9 made of an electric motor 9b for rotating the fan 9a.

At least one indoor side heat exchanger (5) may be installed. The compressor 2 may be at least one of an inverter compressor and a constant speed compressor.

In addition, the air conditioner 40 may be configured as a cooler for cooling the room, or may be configured as a heat pump for cooling or heating the room.

On the other hand, the electric motor in the motor control apparatus of the air conditioner according to an embodiment of the present invention may be each electric motor (2b, 5b, 9b) to operate the outdoor fan, compressor or indoor fan shown in the figure.

2 is a circuit diagram illustrating a motor control apparatus of an air conditioner according to an embodiment of the present invention.

Referring to the drawings, the motor control apparatus 200 of the air conditioner of FIG. 2 includes a converter 210, a first inverter 220, a second inverter 225, and a microcomputer 230. In addition, the motor control apparatus 200 of the air conditioner of FIG. 2 may further include a reactor L, a smoothing capacitor C, an output current detecting means E, and the like.

The reactor L is disposed between the commercial AC power supply and the converter 210 to perform power factor correction or boost operation. In addition, the reactor L may perform a function of limiting harmonic currents due to the fast switching of the converter 210.

The converter 210 converts the commercial AC power passed through the reactor L into DC power and outputs the DC power. In the figure, a commercial AC power source is shown as a single-phase AC power source, but may be a three-phase AC power source. The internal structure of the converter 210 also varies according to the type of commercial AC power. For example, in the case of a single phase AC power supply, a half bridge type converter in which two switching elements and four diodes are connected may be used, and in the case of a three phase AC power supply, six switching elements and six diodes may be used.

The converter 210 includes a plurality of switching elements and performs a boosting operation, power factor improvement, and DC power conversion by a switching operation. On the other hand, the converter 210 may be made of a diode or the like to perform rectification without a separate switching operation.

The smoothing capacitor C is connected to the output terminal of the converter 210. The converted DC power output from the converter 210 is smoothed. Hereinafter, the output terminal of the converter 210 is referred to as a dc terminal or a dc link terminal. The DC voltage smoothed at the dc stage is applied to the inverter 220.

The first inverter 220 includes a plurality of inverter switching elements, converts a smoothed DC power source into a commercial AC power source having a predetermined frequency by on / off operation of the switching element, and outputs the same to the three-phase electric motor 250.

The second inverter 225 is connected in parallel with the first inverter 220, includes a plurality of inverter switching elements, and converts a DC power source smoothed by on / off operation of the switching element into a commercial AC power source having a predetermined frequency. It converts and outputs to the three-phase electric motor 250.

In the first inverter 220 and the second inverter 225, the upper arm switching element and the lower arm switching element connected to each other in series are paired, and a total of three pairs of upper and lower arm switching elements are parallel to each other (Sa & S'a, Sb & S). 'b, Sc & S'c). Each switching device has a diode in anti-parallel connection.

The switching elements in the first inverter 220 and the second inverter 225 perform on / off operations of the respective switching elements based on a common inverter switching control signal Sic from the microcomputer 230. As a result, the three-phase AC power supply having the predetermined frequency is output to the three-phase electric motor 250.

As such, by using the first inverter 220 and the second inverter 225 connected in parallel with each other, the current flowing through each inverter can be reduced, so that not only the stability of the inverter element but also the safety of the entire circuit elements in the control device are obtained. Can be secured. Furthermore, a relatively inexpensive inverter can be used, thereby reducing manufacturing costs.

Three-phase electric motor 250 is provided with a stator and a rotor, each phase AC power of a predetermined frequency is applied to the coil of each stator, the rotor is rotated. The type of the motor 250 may be various forms such as a BLDC motor, synRM motor.

The three-phase electric motor 250 may be used as a fan motor or a compressor motor in an outdoor unit of an air conditioner, and may also be used as a fan motor in an indoor unit of an air conditioner.

On the other hand, the microcomputer 230 controls the first inverter 220 and the second inverter 225. That is, in order to control the switching operation of the first inverter 220 and the second inverter 225, a common inverter switching control signal Sic is output to the first inverter 220 and the second inverter 225. The common inverter switching control signal Sic is a PWM switching control signal and is generated and output based on the detected output current i o . Detailed operations of the microcomputer 230 will be described later with reference to FIG. 5.

The output current detecting means E detects the output current of the output terminal of the first inverter 220 or the second inverter 225, that is, the current flowing through the motor 250. The output current detecting means E may be located between the first inverter 220 or the second inverter 225 and the motor 250, and for detecting current, a current sensor, a current trnasformer, a shunt resistor, or the like. This can be used.

The output current detecting means E may be a shunt resistor having one end connected to three lower arm switching elements of the first inverter 220 or the second inverter 225, respectively. The detected output current i o is applied to the microcomputer 230, and an inverter switching control signal Sic is generated based on the detected output current i o .

Meanwhile, when the converter 210 includes a switching element to perform a switching operation, the microcomputer 230 may control the converter. For this purpose, the microcomputer 230 may further include an input current detecting unit and a dc terminal voltage detecting unit. .

In the drawing, the microcomputer 230 outputs a common inverter switching control signal Sic for controlling the first inverter 220 and the second inverter 225 in common, but is not limited thereto. Each inverter switching control signal may be output from the common micom 230, and each inverter switching control signal may be output from a separate micom.

FIG. 3 is an internal block diagram of the microcomputer of FIG. 2.

Referring to the drawings, the microcomputer 230 includes an estimator 305, a current command generator 310, a voltage command generator 320, and a switching control signal output unit 330.

The estimating unit 305 estimates the position and speed v of the rotor of the electric motor based on the output current i o detected by the output current detecting means E. FIG.

The current command generator 310 generates a d, q-axis current command value i * d , i * q through a PI controller or the like based on the estimated speed v and the speed command value v * .

The voltage command generation unit 320 generates a d, q-axis voltage command value (v * d) through a PI controller or the like based on the d, q-axis current command value (i * d , i * q ) and the detected output current (i o ). , v * q )

The switching control signal output unit 330 switches the common inverter to drive the switching elements in the first inverter 220 and the second inverter 225 based on the d, q-axis voltage command values v * d and v * q . The control signal Sic is output to the microcomputer 230.

4 is a circuit diagram illustrating a motor control apparatus of an air conditioner according to an embodiment of the present invention.

Referring to the drawings, the motor control apparatus 400 of the air conditioner of FIG. 4 includes a first converter 410, a second converter 415, an inverter 420, and a microcomputer 430. In addition, the motor control apparatus 400 of the air conditioner of FIG. 6 may further include a reactor 405, a smoothing capacitor C, an input current detecting means A, a dc terminal voltage detecting means D, and the like. .

The electric motor control device 400 of the air conditioner of FIG. 4 is compared to the electric motor control device 200 of the air conditioner of FIG. 2, instead of the first inverter 220 and the second inverter 225 of FIG. 2. The difference is that the first converter 410 and the second converter 415 are used. Accordingly, there is a difference in the operation of the microcomputer 430, the operation of the input current detection means (A) and the dc terminal voltage detection means (D). The following description focuses on these differences.

The first converter 410 includes a plurality of converter switching elements, and converts the commercial AC power that has passed through the reactor L into DC power by outputting the on / off operation of the switching element.

The second converter 415 is connected in parallel with the first converter, includes a plurality of converter switching elements, and converts commercial AC power passed through the reactor L into DC power by an on / off operation of the switching elements. To print.

In the drawings, a commercial AC power source is shown as a three-phase AC power source, but may be a single-phase AC power source.

The first converter 410 and the second converter 415 each have a pair of upper arm switching elements and lower arm switching elements connected in series with each other, and a total of three pairs of upper and lower arm switching elements are parallel to each other (Sa & S'a, Sb & S). 'b, Sc & S'c). Each switching device has a diode in anti-parallel connection.

The switching elements in the first converter 410 and the second converter 415 perform on / off operations of the respective switching elements based on a common converter switching control signal Scc from the microcomputer 430. As a result, the converted DC power is output to the dc terminal.

As such, by using the first converter 410 and the second converter 415 connected in parallel with each other, the current flowing through each converter can be reduced, so that not only the stability of the converter element but also the safety of the entire circuit elements in the control device are obtained. Can be secured. Furthermore, a relatively inexpensive converter can be used, which reduces manufacturing costs.

The microcomputer 430 controls the first converter 410 and the second converter 415. That is, in order to control the switching operation of the first converter 410 and the second converter 415, a common converter switching control signal Scc is output to the first converter 410 and the second converter 415. The common converter switching control signal Scc is a PWM switching control signal and is generated and output based on the detected dc terminal voltage Vdc and the input current i i . Detailed operations of the microcomputer 430 will be described later with reference to FIG. 5.

The input current detecting means A detects an input current i i input from a commercial AC power supply. To this end, a current sensor, a CT (current trnasformer), a shunt resistor, or the like may be used as the input current detecting means A. FIG. The detected input current i i is input to the microcomputer 430 to generate a common converter switching control signal Scc.

The dc end voltage detection means D detects the dc end voltage Vdc which is both ends of the smoothing capacitor C. To this end, the dc end voltage detection means (D) includes a resistor or the like. The detected dc terminal voltage Vdc is input to the microcomputer 430 to generate a common converter switching control signal Scc.

On the other hand, it is also possible to further include an output current detecting means for detecting (i o), the output current for the generation of the inverter switching control signal (Sic) of the inverter 420.

In the drawing, the microcomputer 430 outputs a common converter switching control signal Scc for controlling the first converter 410 and the second converter 415 in common, but is not limited thereto. Each converter switching control signal may be output from the common micom 430, and each converter switching control signal may be output from a separate micom.

FIG. 5 is an internal block diagram of the microcomputer of FIG. 4.

Referring to the drawings, the microcomputer 430 includes a current command generator 510, a voltage command generator 520, and a switching control signal output unit 530.

The current command generator 510 generates a d, q-axis current command value (i * d , i * q ) through a PI controller or the like based on the detected dc end voltage (Vdc) and the dc end voltage command value (V * dc). Create

The voltage command generation unit 520 performs the d, q-axis voltage command value (v * d) through the PI controller or the like based on the d, q-axis current command value (i * d , i * q ) and the detected input current (i i ). , v * q )

The switching control signal output unit 530 switches the common converter to drive the switching elements in the first converter 410 and the second converter 415 based on the d, q-axis voltage command values v * d and v * q . The control signal Scc is output to the microcomputer 430.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1 is a schematic diagram of an air conditioner according to the present invention.

2 is a circuit diagram illustrating a motor control apparatus of an air conditioner according to an embodiment of the present invention.

FIG. 3 is an internal block diagram of the microcomputer of FIG. 2.

4 is a circuit diagram illustrating a motor control apparatus of an air conditioner according to an embodiment of the present invention.

FIG. 5 is an internal block diagram of the microcomputer of FIG. 4.

<Explanation of symbols on main parts of the drawings>

210: converter 220: first inverter

225: second inverter 230, 430: microcomputer

410: first converter 415: second converter

420: inverter

Claims (8)

A first inverter converting the input DC power into AC power by a switching operation to drive an electric motor; And And a second inverter connected in parallel to the first inverter and converting the DC power into AC power by a switching operation to drive the electric motor. The method of claim 1, And a microcomputer for controlling the first inverter and the second inverter in common. The method of claim 2, The microcomputer, An estimator estimating a speed based on the detected output current flowing in the motor; A current command generation unit that generates a current command value based on the estimated speed and the speed command value; A voltage command generator for generating a voltage command value based on the current command value and the output current; And And a switching control signal output unit for generating and outputting a common inverter switching control signal based on the voltage command value. The method of claim 1, And a converter for converting commercial AC power into the DC power supply. A first converter for converting the input commercial AC power into DC power by a switching operation; And And a second converter connected in parallel to the first converter and converting the commercial AC power into the DC power by a switching operation. The method of claim 5, And a microcomputer for controlling the first converter and the second converter in common. The method of claim 6, The microcomputer, A current command generator which generates a current command value based on the detected dc terminal voltage which is the output terminal voltage of the first and second converters; A voltage command generation unit that generates a voltage command value based on the current command value and an input current from the commercial AC power supply; And And a switching control signal output unit for generating and outputting a common converter switching control signal based on the voltage command value. The method of claim 1, And an inverter for converting the DC power into an AC power by a switching operation to drive the electric motor.
KR1020080063551A 2008-07-01 2008-07-01 Motor controller of air conditioner KR20100003580A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101331954B1 (en) * 2011-12-12 2013-11-22 엘지전자 주식회사 Air conditioner and controlling apparatus of the same
CN104052274A (en) * 2013-03-13 2014-09-17 Lg电子株式会社 Power converter and air conditioner having the same
CN105783202A (en) * 2016-04-28 2016-07-20 武汉阿帕科技有限公司 Electric power energy-saving management system, method and device
KR20180079821A (en) * 2017-01-02 2018-07-11 엘지전자 주식회사 Chiller

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101331954B1 (en) * 2011-12-12 2013-11-22 엘지전자 주식회사 Air conditioner and controlling apparatus of the same
CN104052274A (en) * 2013-03-13 2014-09-17 Lg电子株式会社 Power converter and air conditioner having the same
EP2779406A3 (en) * 2013-03-13 2015-08-26 LG Electronics, Inc. Power converter and air conditioner having the same
US9742336B2 (en) 2013-03-13 2017-08-22 Lg Electronics Inc. Air conditioner with variable power converter
CN104052274B (en) * 2013-03-13 2017-11-28 Lg电子株式会社 Power-converting device and the air conditioner for possessing the power-converting device
CN105783202A (en) * 2016-04-28 2016-07-20 武汉阿帕科技有限公司 Electric power energy-saving management system, method and device
KR20180079821A (en) * 2017-01-02 2018-07-11 엘지전자 주식회사 Chiller

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