KR20120087733A - Apparatus for controlling motor and air conditioner having the apparatus - Google Patents

Abstract

PURPOSE: A motor controlling device and an air-conditioner having the same are provided to diminish high frequency noise and to improve commutation voltage the stability of a system because a noise diminishing unit is connected to between a common ground of an inverter and high frequency switching converter and a radiation panel. CONSTITUTION: A motor controlling device comprises a control circuit unit, a control unit, and a radiation panel(400). The control circuit unit comprises a converter(210), a smoothing capacitor, and an inverter(230). The converter comprises a switching element for the converter becoming switched by converter controlling signals. The converter commutates the AC voltage of a common power source, thereby outputting commutation voltage. The smoothing capacitor makes the commutation voltage smooth to DC voltage. The inverter comprises a switching element for the inverter becoming switched by inverter controlling signals. The inverter converts the DC voltage into motor driving voltage. The control unit generates the converter controlling signals and inverter controlling signals, thereby respectively driving the converter and the inverter. The radiation panel is fixed to a frame of a body. The radiation panel reduces heat generated by switching the switching element for the converter and the switching element for the inverter. The radiation panel is connected to a ground of the control circuit unit. The radiation panel reduces switching noise caused by switching the switching elements.

Description

A motor control device and an air conditioner having the same {APPARATUS FOR CONTROLLING MOTOR AND AIR CONDITIONER HAVING THE APPARATUS}

The present invention relates to a motor control apparatus and an air conditioner capable of reducing switching noise caused by high frequency switching of switching elements in driving a compressor motor of an air conditioner.

A general air conditioner includes a multi-air conditioner system having a plurality of multi-air conditioners and a central control device for controlling the same, a ventilation system, a general load system, and the like. The multi-air conditioner system may be configured to centrally control a plurality of multi-air conditioners and a plurality of multi-air conditioners including an outdoor unit that controls distribution and circulation of refrigerant and an indoor unit that is shared with the outdoor unit and discharges air into each chamber. It is composed of a central control unit.

Conventional air conditioners are grounded by separating the motor control device into a portion using a relatively high voltage and a portion using a low voltage. Here, the portion using the high voltage may be defined as the analog signal controller, and the portion using the low voltage may be defined as the digital signal controller.

In addition, a conventional motor control apparatus and an air conditioner having the same are separated from the analog signal controller and the digital signal controller by using insulation means such as a relatively expensive photo coupler. In addition, in the related art, the ground connected to the Y-CAP of the noise filter is grounded to the air conditioner frame, and in the case of the control board, the digital signal controller such as microcomputer, sensor, SMPS, IPM, DC Link, etc. The ground planes of the analog signal controllers are controlled in common or separately. Recently, in order to reduce costs, a common ground is applied to an inverter and a converter which performs high frequency switching.

However, in the motor control apparatus and the air conditioner having the same according to the related art, switching noise occurs due to the switching between the inverter and the converter even when the inverter and the converter of the high frequency switching are commonly grounded. The size of the is increased, there is a problem that the reliability of the product is lowered.

The present invention is to solve the problems of the prior art, an object of the present invention is to provide a motor control device for reducing switching noise by grounding the control ground of the serial link capacitor, the heat sink and an air conditioner having the same.

Another object of the present invention is to provide a motor control device for reducing high frequency noise by connecting a common ground of an inverter and a high frequency switching converter, a heat sink, and connecting a noise reduction unit therebetween, and an air conditioner having the same.

Motor control apparatus according to the present invention for achieving the above object is provided with a converter switching element that is switched in accordance with the converter control signal, a converter for rectifying the AC voltage of the commercial power supply to output a rectified voltage, and the rectified voltage DC A control circuit section including a smoothing capacitor for smoothing the voltage, an inverter switching element switched according to an inverter control signal, and an inverter for converting the DC voltage into a motor driving voltage, and the converter control signal and the inverter control signal. And a heat dissipation plate which is generated and is fixed to a frame of the main body, respectively, and which drives the converter and the inverter, and reduces heat generated by the switching of the converter switching element or the inverter switching element. Is connected to the ground of the control circuit unit Switching noise caused by switching of the switching element for converter or the switching element for inverter is reduced.

The motor control apparatus according to the present invention further comprises a noise reduction unit connected between the ground of the control circuit unit and the heat sink and configured to attenuate the switching noise.

In the motor control apparatus according to the present invention, the heat sink is characterized in that the ground to the frame. Here, the noise reduction unit prevents ground short with the heat sink.

The motor control apparatus according to the present invention further comprises a noise filter connected to the control circuit part and grounded to the frame and preventing the switching noise from being output to the outside. In addition, the noise filter is connected between the commercial power supply and the converter to further prevent input noise input together with the commercial power supply.

The motor control apparatus according to the present invention further includes an insulation member provided between the converter switching element or the inverter switching element, and the heat sink, and a connection member connecting the heat sink and the frame.

In the motor control apparatus according to the present invention, the converter switching element is driven at a switching frequency of 40 KHz or higher.

An air conditioner according to the present invention for achieving the above objects, one or more indoor units for performing air conditioning, a compressor for compressing the refrigerant to a high temperature, high pressure, a motor for driving the compressor, and a motor for controlling the driving of the motor And an outdoor unit connected to the at least one indoor unit through a pipe and driving the indoor unit, wherein the motor control unit includes a plurality of switching elements and is switched according to a control signal to drive the motor. And a heat sink connected to a control circuit unit, a ground connected to the ground of the control circuit unit, heat generated by switching of the plurality of switching elements, and a switching noise.

In the air conditioner according to the present invention, the outdoor unit, an evaporator for heat dissipating the refrigerant compressed by the compressor with air, an expansion valve for expanding the refrigerant radiated from the evaporator to low temperature, low pressure, and And a refrigerant switching valve provided at the outlet of the compressor to heat-exchange the low-temperature and low-pressure refrigerant with water, and guide the refrigerant compressed by the compressor to the evaporator or the condenser.

In the air conditioner according to the present invention, the control circuit unit is provided with a converter switching element that is switched in accordance with the converter control signal, the converter for rectifying the AC voltage of the commercial power supply to output a rectified voltage, and the rectified voltage DC voltage And an inverter including a smoothing capacitor to be smoothed and an inverter switching element switched according to an inverter control signal, and converting the DC voltage into a motor driving voltage, thereby forming a common ground.

The present invention reduces the temperature of the switching elements while reducing the switching noise by grounding the control ground of the series link capacitor and the heat sink.

The present invention attenuates high frequency noise by connecting a common ground of an inverter and a high frequency switching converter, a heat sink, and a noise damping unit therebetween, and improves the stability of the system.

The present invention can reduce the noise and reduce the cost by reducing the size of the noise filter by using relatively inexpensive elements, and by not using elements such as photo couplers.

1 is a view schematically showing a configuration of an example of an air conditioner with a motor control device according to the present invention;
2 schematically shows an example of a circuit board of a motor control apparatus mounted on a frame;
3 and 4 show a connection relationship between the control circuit unit and the heat sink according to the present invention;
5 schematically shows the configuration of a motor control apparatus according to the present invention;
6 and 7 are block diagrams showing the configuration of a motor control apparatus according to embodiments of the present invention;
8 is a block diagram schematically showing the configuration of the noise filter in FIGS. 5 and 7;
9 is a circuit diagram illustrating an example of a noise filter in FIG. 8.

Hereinafter, a motor control apparatus and an air conditioner having the same according to the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the air conditioner according to the present invention includes one or more indoor units 20 for performing air conditioning, a compressor 12 for compressing a refrigerant to high temperature and high pressure, a motor for driving the compressor, and It includes a motor control device for controlling the driving of the motor, the outdoor unit 10 is connected to the at least one indoor unit through a pipe to drive the indoor unit. Here, the motor control device, as shown in Figure 2, is provided with a plurality of switching elements, is connected in accordance with a control signal to the control circuit unit 200 for driving the motor, and the ground of the control circuit unit, It is configured to include a heat sink 400 to reduce the heat generated by the switching of the plurality of switching elements and the switching noise.

The outdoor unit 10 includes an evaporator 13 for exchanging heat by heat exchange of the refrigerant compressed by the compressor with air, an expansion valve 14 for expanding the refrigerant radiated from the evaporator at low temperature and low pressure, and the A condenser 15 for exchanging low temperature and low pressure refrigerant with water and a refrigerant provided at an outlet of the compressor 12 to guide the refrigerant compressed by the compressor to the evaporator 13 or the condenser 15. It further comprises a switching valve (17).

Referring to FIG. 1, in the outdoor unit 10, a refrigeration cycle including a compressor 12, an evaporator 13, an expansion valve 14, and a condenser 15 is installed in the case 11. A plurality of intake fans 16 are installed on the top or side surfaces of the 11 to allow the outside air to be exchanged with the evaporator 13, and the condenser 15 supplies cold water or hot water to the indoor units 20. Medium circulation pipe 30 for connecting is connected. At the outlet of the compressor 12, a refrigerant switching valve 17 for converting the refrigerant compressed by the compressor 12 in the evaporator direction or the condenser direction according to the operating conditions is installed. The refrigerant switching valve 17 is usually composed of a four-way valve. The outdoor unit 10 as described above is operated by switching to a heater in winter while operating as a cooler in summer. For example, in the summer, the refrigerant is compressed at high temperature and high pressure in the compressor 12, the refrigerant switching valve is guided to the evaporator 13, the heat exchanged with the air in the evaporator 13, heat dissipation, and the low temperature, After making low pressure and heat exchange with the water in the condenser 15, the heat exchanged water is supplied to the indoor units 20 used as a cooling heat source. Meanwhile, in winter, the refrigerant switching valve 17 guides the refrigerant toward the condenser so that the high temperature and high pressure refrigerant exchanges heat with the water in the condenser 15 to the indoor units 20 using the heat exchanged water as a heating heat source. Supply.

Referring to FIG. 5, the control circuit unit 200 includes a converter 210 having a converter switching element switched according to a converter control signal, rectifying an AC voltage of a commercial power supply, and outputting a rectified voltage, and the rectified voltage. A smoothing capacitor (220) for smoothing the voltage to a DC voltage, and an inverter (230) having an inverter switching element switched according to an inverter control signal and converting the DC voltage into a motor driving voltage, and forming a common ground. .

Referring to FIG. 6, the motor control apparatus according to the present invention includes a converter 210 having a converter switching element switched according to a converter control signal, rectifying an AC voltage of a commercial power supply, and outputting a rectified voltage. A control circuit 200 including a smoothing capacitor 220 for smoothing a voltage to a DC voltage, an inverter switching element switched according to an inverter control signal, and an inverter 230 for converting the DC voltage into a motor driving voltage. And a control unit 250 for driving the converter and the inverter by generating the converter control signal and the inverter control signal, respectively, and fixed to the frame FRAME of the main body, the switching element for the converter or the switching for the inverter. And a heat sink 400 for reducing heat generated by switching of the device, wherein the heat sink 400 is a ground of the control circuit part. It is associated with and reducing the switching noise due to the switching of the switching device or the switching device for the drive for the converter.

The converter 210 rectifies the AC voltage of the commercial power supply 100 using a diode rectifier or the like. That is, the converter 210 converts a commercial AC voltage into a DC voltage in the form of a pulse. In addition, the converter 210 further includes a switching element for a converter such as an insulated gate bipolar transistor (IGBT), a MOSFET, or the like, and according to a converter control signal from the control unit 250. The input voltage can be stepped up or down. In this case, the converter control signal is generally a PWM signal that controls the pulse width modulation (PWM) voltage duty of the converter 210. The converter switching element is driven at a switching frequency of 40 KHz or higher and at a high frequency.

The smoothing capacitor 220, the DC link capacitor (DC Link Capacitor), is composed of a single capacitor or a simple circuit including the same, smoothing the rectified voltage output from the converter 210 to output and store a DC voltage. The ground of the smoothing capacitor 220 forms a common ground with the converter and the inverter and is connected to the heat sink.

The inverter 230 includes a plurality of switching elements, and transmits a motor driving voltage and a motor driving current to the motor 300 of the compressor according to an inverter control signal generated from the control unit 250, for example, a PWM driving signal. Is authorized.

The motor control apparatus may further include a DC link current detection unit connected to the DC link capacitor 220 and detecting a current output from the smoothing capacitor 220, or a DC link voltage detection unit detecting a voltage thereof. have. The motor control apparatus may further include an output current detection unit connected between the inverter and the motor to detect the motor driving current. Here, the output current detection unit may be a current transducer, the current transducer detects the motor driving current and converts it to a voltage signal and outputs it to the control unit 250, pulse width modulation The motor driving current may be detected in all sections of the motor. In addition, the output current detection unit may be a shunt resistor connected to the lower arm of the inverter. The motor control device may further include a detection unit that detects a current or voltage input from a commercial power source.

The control unit 250 detects a state of the motor 300 and supplies an inverter control signal to the inverter 230 based on the motor operation state to supply DC power through the inverter 230 to a motor driving voltage and Convert it to current. Here, the inverter control signal is generally a PWM signal that controls the PWM voltage duty of the inverter 230.

In addition, the control unit 250 may be connected to a central controller (not shown) for driving an air conditioner or included in the central controller, and may be driven in conjunction with an air conditioner operation. For example, an inverter control signal for increasing the capacity of the compressor motor 300 may be supplied to the inverter to increase cooling.

The heat sink 400 reduces heat generated by switching of a switching element of a converter or an inverter. 3 or 4, the heat sink is insulated with an insulating member 410 between the converter switching element or the inverter switching element. In this case, the insulating member 410 is formed thin like an insulation paper. In addition, the heat sink is connected to the frame through the connection member 420. In this case, the connection member 420 is made of a non-insulating material so that the heat sink 400 is used as a conductor, and the heat sink 400 is connected to the frame through the connection member 420 and grounded at the same time. Can be.

6 or 7, the motor control apparatus further includes a noise attenuation unit 500 connected between the ground of the control circuit unit 200 and the heat dissipation plate to attenuate the switching noise. . When connected as shown in FIG. 4, the heat sink 400 may be grounded to the frame, and the noise attenuation unit 500 prevents ground short with the heat sink.

4 to 7, the noise reduction unit 500 is connected between the control circuit unit and the heat sink and grounded. Accordingly, the noise attenuation unit 500 attenuates high frequency noise generated by high frequency switching of the switching elements of the inverter and the converter. The noise attenuation unit 500 may be a capacitor that is connected between the common ground of the control circuit unit and the heat sink, and attenuates switching noise. The common ground of the control circuit part is a ground connected in common between the high frequency switching converter and the inverter, and is a ground of a smoothing capacitor, that is, a DC link capacitor. In this case, when the motor 300 operates at a high frequency of a specific frequency or more, an impedance due to a capacitor is reduced, thereby reducing noise due to switching of the motor.

Referring to FIG. 7, the motor control device may further include a noise filter 700 connected to the control circuit part and grounded to the frame, and preventing the switching noise from being output to the outside. In addition, the noise filter 700 is further connected between the commercial power supply and the converter to further prevent input noise input together with the commercial power supply.

Referring to FIG. 8, the noise filter 700 may include a first power storage unit 710 connected between two power lines of the commercial power supply 100 and the first power storage unit, and the common mode of the power line. A first choke 720 for attenuating noise and a second power storage unit 730 connected to the first choke and attenuating the common mode noise together with the first choke are configured. Here, the first choke 720 includes two coils 721 and 722 wound in opposite directions. The noise filter further includes a second choke 740 connected between the first choke 720 and the second power storage unit 730 to attenuate the differential mode noise of the power supply line. .

The first power storage unit 710 may perform a function of a matching capacitor for matching impedance of a circuit.

On the other hand, the first power storage unit 710 is also referred to as an X capacitor (X-CAP), the X capacitor is used to suppress the differential mode noise (Differential Mode Noise). Differential mode noise is caused by the differential mode current component and is noise present between the power lines for the input power source. The X capacitor forms a short path to the differential mode noise, preventing the differential mode noise from leaving the device.

In addition, the first power storage unit 710 may be used together with the second choke 740 to remove the differential mode noise. In the case where the first power storage unit 710 is used for differential mode noise, a capacitor having a sufficient capacity can be used because the capacity is not limited. This is effective for attenuating differential mode noise.

The second choke 740 includes differential mode coils 741 and 742, and suppresses the differential mode high frequency introduced from both power lines through counter electromotive force, and the first power storage unit 710 includes two differential mode coils. Absorb high frequencies caused by an imbalance in the frequencies output from 741 and 742. This attenuates the differential mode noise that is fed back into the input supply.

The second power storage unit 730 and the first choke 720 are used to attenuate common mode noise.

The second power storage unit 730 is referred to as a Y capacitor (Y-CAP), a first capacitor 731 connected between one end of the first choke 720 and the ground 600, and the ground 600. And a second capacitor 732 connected between and the other end of the first choke 720. Since the second power storage unit 730 is connected between the ground 600 and the power supply, the leakage current increases as the capacity increases. Therefore, it is necessary to limit the capacity of the second power storage unit 730, so that it is used together with the first choke 720 to remove common mode noise. The ground 600 to which the second power storage unit 730 is connected may be a ground of a circuit board, or may be a frame or ground ground to stably absorb high frequency waves.

The first choke 720 has an impedance with respect to common mode noise and is composed of common mode coils 721 and 722 which attenuate common mode noise. In addition, the noise filter including the first choke 720 prevents switching noise due to the motor driving from being transmitted to the input power. That is, the inflow of the common mode high frequency generated by the motor 300 is blocked by using the counter electromotive force.

The first choke 720 includes common mode coils 721 and 722, and the common mode coils 721 and 722 are wound in opposite directions as shown in FIG. 9. That is, the common mode coils 721 and 722 are rotated 90 degrees so that the polarity of the upper and lower sides is different.

As shown in Fig. 9, the dots indicating the polarities of the mutually coupled coils follow the dot convention. That is, when the reference direction of the current is directed to the dot display terminal of the coil, the reference polarity of the voltage induced in the other coil is positive in the dot display terminal. On the other hand, when the reference direction of the current is outside the dot display terminal of the coil, the reference polarity of the voltage induced in the other coil is negative in the dot display terminal.

As described above, by winding the wirings of the common mode coils 721 and 722 in opposite directions, and adjusting the capacitance and the pattern of the second power storage unit 730, the second choke 740, that is, the differential mode coils are completely removed. You can configure the noise filter with or without reduction. In other words, by winding the wiring of the common mode coils 721 and 722 in opposite directions as described above, parasitic noise can be eliminated and the attenuation characteristics can be improved, and the common mode choke can replace the function of the differential mode choke. have.

The common mode coil may be a coil capable of being formed as a waste including a toroidal coil, a U-shaped coil, an SQ coil, and the like to block the inflow of the common mode high frequency wave. In addition, the core of the common mode coil may be a ferrite magnetic material capable of receiving high frequency absorption.

As described above, the motor control apparatus and the air conditioner including the same according to the present invention, by reducing the temperature of the switching elements while reducing the temperature of the switching elements by grounding the control ground and the heat sink of the smoothing capacitor, the inverter and the high frequency switching The high frequency noise is attenuated by grounding the common ground of the converter and the heat sink and connecting a noise attenuation capacitor therebetween.

100: commercial power supply 200: control circuit
300: motor 400: heat sink
500: noise reduction unit 600: ground
700: noise filter

Claims (19)

A converter having a converter switching element switched according to a converter control signal and rectifying an AC voltage of a commercial power supply to output a rectified voltage, a smoothing capacitor for smoothing the rectified voltage to a DC voltage, and switched according to an inverter control signal A control circuit unit having an inverter switching element and having an inverter which converts the DC voltage into a motor driving voltage;
A control unit generating the converter control signal and the inverter control signal to drive the converter and the inverter, respectively; And
And a heat sink fixed to a frame of the main body, the heat sink configured to reduce heat generated by the switching of the converter switching element or the inverter switching element.
The heat sink is connected to the ground of the control circuit portion motor control device, characterized in that for reducing the switching noise caused by the switching of the switching element for the converter or the switching element for the inverter. The method according to claim 1,
And a noise attenuation unit connected between the ground of the control circuit unit and the heat sink and configured to attenuate the switching noise. The method of claim 2,
And the heat sink is grounded to the frame. The method of claim 3,
The noise reduction unit prevents ground short with the heat sink. 5. The method according to any one of claims 1 to 4,
And a noise filter connected to the control circuit part and grounded to the frame and preventing the switching noise from being output to the outside. 6. The method of claim 5,
The noise filter is connected between the commercial power supply and the converter, characterized in that to further prevent input noise input with the commercial power. The method of claim 5, wherein the noise filter,
A first power storage unit connected between two power lines of the commercial power source;
A first choke connected to the first power storage unit and attenuating common mode noise of the power supply line; And
And a second power storage unit connected to the first choke and attenuating the common mode noise together with the first choke.
And the first choke comprises two coils wound in opposite directions. The method of claim 6, wherein the second power storage unit,
Including two capacitors,
And a ground to the frame is formed between the capacitors. The method of claim 6, wherein the noise filter,
And a second choke connected between the first choke and the second power storage unit to attenuate the differential mode noise of the power supply line. The method of claim 9, wherein the second choke,
Motor control device characterized in that the configuration is formed by winding the conductor wire on the two bar cores. The method according to claim 1,
An insulating member provided between the converter switching element or the inverter switching element and the heat sink; And
And a connection member connecting the heat sink and the frame. 5. The method according to any one of claims 1 to 4,
The converter switching element is driven at a switching frequency of 40 KHz or more. One or more indoor units to perform air conditioning; And
An outdoor unit having a compressor for compressing a refrigerant at a high temperature and a high pressure, a motor for driving the compressor, and a motor control device for controlling the driving of the motor, the outdoor unit being connected through at least one indoor unit and a pipe to drive the indoor unit; Including,
The motor control device includes:
A control circuit unit having a plurality of switching elements and switched according to a control signal to drive a motor; And
And a heat sink connected to the ground of the control circuit unit and configured to reduce heat generated by switching of the plurality of switching elements and switching noise. The method of claim 13, wherein the outdoor unit,
An evaporator for heat dissipating the refrigerant compressed by the compressor by heat exchange with air;
An expansion valve for expanding the refrigerant radiated from the evaporator to low temperature and low pressure;
A condenser for exchanging heat of the low temperature and low pressure refrigerant with water; And
And a refrigerant switching valve provided at an outlet of the compressor to guide the refrigerant compressed by the compressor to the evaporator or the condenser. The method according to claim 13 or 14, wherein the control circuit unit,
A converter having a converter switching element switched according to a converter control signal and rectifying an AC voltage of a commercial power supply to output a rectified voltage;
A smoothing capacitor that smoothes the rectified voltage to a direct current voltage; And
And an inverter having a switching element for inverter switched according to an inverter control signal and converting the DC voltage into a motor driving voltage.
An air conditioner, which forms a common ground. The method of claim 15, wherein the motor control device,
And a noise attenuation unit connected between the ground of the control circuit unit and the heat sink and configured to attenuate the switching noise. 17. The method of claim 16,
And the heat sink is grounded to the frame. The method of claim 17,
And the noise attenuation capacitor prevents ground short with the heat sink. The motor control device according to claim 13 or 14,
And a noise filter connected to the control circuit part and grounded to the frame and preventing the switching noise from being output to the outside.

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