KR102346445B1 - Power transforming apparatus and air conditioner including the same - Google Patents

Abstract

In order to achieve the object of the present invention, a power conversion device according to an embodiment of the present invention includes a reactor connected to power supplied to the power conversion device, a converter to which an output voltage of the reactor unit is applied, and an output terminal of the reactor unit It is characterized in that it comprises a core for winding the side conductor.

Description

POWER TRANSFORMING APPARATUS AND AIR CONDITIONER INCLUDING THE SAME

The present invention relates to a power conversion device, and more particularly, to a method of protecting a power conversion device provided in an air conditioner.

In general, an air conditioner includes an indoor unit configured as a heat exchanger and installed indoors, and an outdoor unit configured as a compressor and a heat exchanger and supplying refrigerant to the indoor unit.

Such an air conditioner is controlled by being separated into an indoor unit composed of a heat exchanger and an outdoor unit composed of a compressor and a heat exchanger. That is, the air conditioner drives the indoor unit and the outdoor unit by controlling the power supplied to the compressor or the heat exchanger.

Meanwhile, the air conditioner includes a power conversion device for supplying AC power to the motor of the compressor. For example, the power conversion device provided in the air conditioner may include a rectifying unit, a power factor control unit, and an inverter unit.

The AC commercial voltage output from the commercial power supply is rectified by the rectifying unit. The voltage rectified by the rectifying unit is supplied to a power conversion unit such as an inverter. In this case, the power converter generates AC power for driving the motor by using the voltage output from the rectifier.

In some cases, a DC-DC converter for improving the power factor may be provided between the rectifying unit and the inverter.

On the other hand, in order to remove common mode noise generated by the converter, it is common to include a noise removing core that winds the conducting wire constituting the power conversion device.

The conventional power conversion device removes common mode noise by winding both the input end-side conducting wire and the output end-side conducting wire of the reactor on a single noise canceling core.

When the power conversion device includes a plurality of reactors, a noise removing core having an increased size is required to wind all the conductive wires, and in this case, there is a problem in that the manufacturing cost of the power conversion device is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power conversion device that minimizes the size of a noise removing core for removing common mode noise, and an air conditioner including the same.

In addition, the technical problem of the present invention is to reduce the manufacturing cost of the power conversion device by reducing the size of the noise removal core.

In order to solve the above problems, the power conversion device according to an embodiment of the present invention is connected to a reactor connected to power supplied to the power conversion device, a converter receiving the output voltage of the reactor unit, and the reactor unit, , characterized in that it includes a noise canceling core for removing common mode noise.

In an embodiment, the reactor unit includes a first reactor and a second reactor, the first reactor and the second reactor are connected in parallel, and the noise removal core includes an output end-side conductive wire of the first reactor, It is characterized in that the winding of the output terminal side of the second reactor.

In an embodiment, the output terminal-side conductive wire of the first reactor and the output terminal-side conductive wire of the second reactor are wound around the noise removal core in opposite directions to each other.

In an embodiment, the first reactor and the second reactor are disposed between an external power source and the converter, and the noise removal core connects the converter-side conductor of the first reactor and the converter-side conductor of the second reactor. It is characterized by winding.

In an embodiment, the first magnetic flux generated by the converter-side conductor of the first reactor wound around the noise removal core and the second magnetic flux generated by the converter-side conductor of the second reactor wound around the noise removing core The two magnetic fluxes are formed in the same direction in the noise canceling core formed as a ring.

In an embodiment, the noise removal core winds up a first conductor that is any one of the conductors connected to both ends of the first reactor and a second conductor that is any one of the conductors connected to both ends of the second reactor, and the noise is removed Currents flowing through the two conductors wound around the core are in the same direction with respect to the reactor unit.

In another embodiment of the power conversion device according to the present invention, it is connected to both ends of the reactor unit, characterized in that it comprises a first noise removing core and a second noise removing core for removing common mode noise.

In one embodiment, the first noise removing core is characterized in that the winding of the output end-side conducting wire of the first reactor and the input end-side conducting line of the second reactor.

In one embodiment, the second noise removal core is characterized in that the winding of the input end-side conducting wire of the first reactor and the output end-side conducting line of the second reactor.

In an embodiment, the output end-side conducting wire of the first reactor and the input end-side conducting wire of the second reactor are wound around the first noise removing core in the same direction.

In an embodiment, the output end-side conducting wire of the second reactor and the input end-side conducting line of the first reactor are wound around the second noise removing core in the same direction.

Effects of the power conversion device and the air conditioner including the same according to the present invention will be described as follows.

According to at least one of the embodiments of the present invention, since it is not necessary to wind all the conductors connected to both ends of the reactor, there is an advantage in that the size of the noise removal core can be reduced.

In addition, since the size of the noise removal core is reduced, an effect of reducing the manufacturing cost of the power conversion device and the air conditioner including the same is derived.

1 is a block diagram illustrating a power conversion device.
2 is a conceptual diagram for explaining a noise canceling core that removes common mode noise.
3 is a conceptual diagram illustrating a method of winding all the conductors connected to both ends of the reactor by the conventional noise canceling core.
4 is a conceptual diagram illustrating a method of winding all the conductors connected to both ends of the reactor by the conventional noise canceling core.
5 is a conceptual diagram illustrating a method in which a noise canceling core winds a portion of a conductor connected to a reactor according to an embodiment proposed by the present invention.
6 is a conceptual diagram illustrating a method in which a noise canceling core winds a portion of a conductor connected to a reactor according to an embodiment proposed by the present invention.
7 is a conceptual diagram illustrating a method in which a noise canceling core winds a portion of a conductor connected to a reactor according to another embodiment proposed by the present invention.
8 is a conceptual diagram illustrating a method in which a noise canceling core winds a portion of a conductor connected to a reactor according to another embodiment proposed by the present invention.

Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but the same or similar components are assigned the same reference numbers regardless of reference numerals, and redundant description thereof will be omitted. The suffixes "module" and "part" for components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have distinct meanings or roles by themselves. In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical idea disclosed herein is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present invention , should be understood to include equivalents or substitutes.

1 is a block diagram illustrating a power conversion device according to the present invention.

Referring to FIG. 1, the power conversion device 1000 includes a rectifier 1100 for rectifying an AC power source 100, a converter unit 1200 for step-up/step-down of the DC voltage rectified by the rectifier 1100 or for controlling the power factor 1200, and a converter control unit 1300 for controlling the converter unit 1200 . In addition, the power conversion apparatus 1000 may further include an inverter unit 1400 outputting a three-phase alternating current and an inverter control unit 1500 controlling the inverter unit 1400 .

The inverter unit 1400 outputs a three-phase alternating current, and this output current is supplied to the motor 2000 . Meanwhile, the power conversion device 1000 may include an inverter controller 1500 for controlling the inverter unit 1400 , and a DC terminal capacitor C between the converter unit 1200 and the inverter unit 1400 .

Here, the motor 2000 may be a compressor motor that drives the air conditioner. Hereinafter, the motor 2000 may be a compressor motor driving the air conditioner, and the power conversion device 1000 may be a motor driving device driving the compressor motor.

The inverter unit 1400 outputs a three-phase alternating current, and this output current is supplied to the motor 2000 . Here, the motor 2000 may be a compressor motor that drives the air conditioner. Hereinafter, it will be described that the motor 2000 is a compressor motor that drives the air conditioner, and the power conversion device 1000 is a motor driving device that drives the compressor motor as an example.

However, the motor 2000 is not limited to the compressor motor, and may be used in various application products using a frequency-variable AC voltage, for example, AC motors such as refrigerators, washing machines, electric vehicles, automobiles, and vacuum cleaners.

Meanwhile, the power conversion device 1000 may further include a DC terminal voltage detector (B), an input voltage detector (A), an input current detector (D), and an output current detector (E) to drive the compressor motor. have.

The power conversion device 1000 receives AC power from the system, converts the power, and supplies the converted power to the motor 2000 .

The converter unit 1200 converts the input AC power supply 100 into a DC power supply. The converter unit 1200 may use a DC-DC converter operating as a power factor control unit (PFC). In addition, the DC-DC converter may use a boost converter. In some cases, the converter unit 1200 may be a concept including the rectifying unit 1100 . Hereinafter, the converter unit 1200 will be described as an example using a step-up converter.

The rectifying unit 1100 receives and rectifies the single-phase AC power supply 100 , and outputs the rectified power to the converter unit 1200 side. To this end, the rectifier 1100 may use a full-wave rectification circuit using a bridge diode.

In this way, the converter unit 1200 may perform a power factor improvement operation in the process of boosting and smoothing the voltage rectified by the rectifying unit 1100 .

The converter unit 1200 includes an inductor L1 connected to the rectifying unit 1100, a switching element Q1 connected to the inductor L1, a capacitor C connected in parallel with the switching element Q1, and a diode D1 connected between the switching element Q1 and the capacitor C.

The converter unit 1200 is a step-up converter capable of obtaining an output voltage higher than the input voltage. When the switching element Q1 is turned on, the diode D1 is cut off and energy is stored in the inductor L1, and energy is stored in the capacitor C. As the stored charge is discharged, an output voltage is generated at the output terminal.

In addition, when the switching element Q1 is cut off, the energy stored in the inductor L1 is added when the switching element Q1 is turned on and transferred to the output terminal.

Here, the switching element Q1 may perform a switching operation according to a separate pulse width modulation (PWM) signal.

That is, the PWM signal transmitted from the converter control unit 130 is transmitted to the converter driving unit 1600 , and the converter driving unit 1600 is connected to a base (or gate) terminal of the switching element Q1 , and this PWM signal Thus, the switching operation of the switching element Q1 may be driven.

For example, the switching element Q1 of the converter unit 1200 may have a gate terminal connected to the converter driver 1600 and an emitter terminal connected to a node between the converter driver 1600 and the device protection unit 1800 . .

The switching element Q1 may use a power transistor, for example, an insulated gate bipolar mode transistor (IGBT).

The IGBT is a switching device having a structure of a power MOSFET (metal oxide semi-conductor field effect transistor) and a bipolar transistor, and is a device capable of low driving power, high-speed switching, high withstand voltage, and high current density.

In this way, the converter control unit 1300 may control the turn-on timing of the switching element Q1 in the converter unit 1200 . Accordingly, the converter control signal Sc for the turn-on timing of the switching element Q1 may be output.

To this end, the converter control unit 1300 may receive the input voltage Vs and the input current Is from the input voltage detection unit A and the input current detection unit B, respectively.

In addition, the output voltage passing through the rectifying unit 1100 may be charged in the DC terminal capacitor C or drive the inverter unit 1400 .

The input voltage detection unit A may detect an input voltage Vs from the input AC power source 100 . For example, it may be located in front of the rectifying unit 1100 .

The input voltage detection unit A may include a resistance element, an OP AMP, and the like for voltage detection. The detected input voltage Vs is a discrete signal in the form of a pulse, and may be applied to the converter control unit 1300 to generate the converter control signal Sc.

Next, the input current detection unit D may detect the input current Is from the input AC power source 100 . Specifically, it may be located in front of the rectifying unit 1100 .

The input current detection unit D may include a current sensor, a current transformer (CT), a shunt resistor, and the like for current detection. The detected input voltage Is is a discrete signal in the form of a pulse, and may be applied to the converter control unit 1300 to generate the converter control signal Sc.

The DC voltage detection unit B detects the pulsating voltage Vdc of the DC stage capacitor C. For this power detection, a resistance element, an OP AMP, etc. may be used. The detected voltage (Vdc) of the DC terminal capacitor (C) is a discrete signal in the form of a pulse, and may be applied to the inverter control unit 1500, and is applied to the DC voltage (Vdc) of the DC terminal capacitor (C). Based on the inverter control signal Si may be generated.

Meanwhile, unlike the drawing, the detected DC voltage may be applied to the converter control unit 1300 and used to generate the converter control signal Sc.

On the other hand, the power conversion device according to the present invention can reduce the electrical noise by adjusting the zero vector ratio of the output signal by PWM control. In this regard, in order to drive the motor 2000 through the inverter unit 1400, the present invention uses the Space Vector PWM modulation method. Meanwhile, in the Space Vector PWM modulation method, electrical noise is generated at a frequency twice as high as the corresponding frequency according to the switching frequency. In this case, the corresponding noise may be generated within an audible frequency by switching on/off at a frequency of 4 to 7 kHz, and thus may cause discomfort to consumers when the surrounding noise is small. In order to solve this problem, the present invention proposes a method of reducing a noise peak component by continuously changing the ratio of a zero vector section in which no current flows in the SV-PMW method in order to reduce electrical noise.

In this regard, the inverter unit 1400 according to the present invention converts DC power into three-phase AC power of a predetermined frequency by on/off operation of a plurality of inverter switching elements.

The inverter unit 1400 includes a plurality of inverter switching elements Qa, Qb, Qc, Qa', Qb', and Qc', and provides a predetermined DC power supply (Vdc) smoothed by on/off operation of the switching elements. The frequency may be converted into three-phase AC power and output to the three-phase motor 2000 .

Specifically, the inverter unit 1400 includes a pair of upper switching elements Qa, Qb, Qc and lower switching elements Qa', Qb', Qc' connected in series with each other, and a total of three pairs of upper and lower The switching elements may be connected in parallel to each other.

Like the converter unit 1200, the switching elements Qa, Qb, Qc, Qa', Qb', and Qc' of the inverter unit 1400 may use a power transistor, for example, an insulated gate bipolar transistor ( An insulated gate bipolar mode transistor (IGBT) can be used.

The inverter control unit 1500 may output an inverter control signal Si to the inverter unit 1400 to control the switching operation of the inverter unit 1400 . The inverter control signal Si is a pulse width modulation (PWM) switching control signal, and is generated based on the output current io flowing through the motor 2000 and the DC terminal voltage Vdc at both ends of the DC terminal capacitor C can be printed out. At this time, the output current io may be detected from the output current detection unit E, and the DC terminal voltage Vdc may be detected from the DC terminal voltage detection unit B.

The output current detection unit E may detect the output current io flowing between the inverter unit 1400 and the motor 2000 . That is, the current flowing through the motor 2000 is detected. The output current detection unit E may detect all of the output currents ia, ib, and ic of each phase, or may detect the output currents of the two phases using three-phase balance. The output current detection unit E may be positioned between the inverter unit 1400 and the motor unit 2000 , and a current transformer (CT), a shunt resistor, or the like may be used to detect the current.

On the other hand, in the present invention, the output current (ia, ib, ic) or the corresponding output voltage (Va, Vb, Vc) at the point where the inverter unit 1400 and the motor 2000 are connected to the first and third outputs It can be referred to as a signal.

According to the present invention, it is possible to dynamically control the electric noise by the first to third output signals output from the inverter unit 1400 to the motor 2000 by the PWM control signal.

Meanwhile, referring to FIG. 1 , a noise filter unit 1700 is disposed between the input power source and the converter unit. An apparatus for performing a noise filter may be implemented in various forms, but the noise filter 1700 proposed in the present invention includes the reactors 1700a and 1700b and the reactors 1700a and 1700b in order to remove common mode noise. ) and at least one ring-shaped noise removing core for removing the common mode noise by winding some of the conductors provided in the power conversion device.

2 shows a noise canceling core for removing common mode noise.

As shown in FIG. 2 , when the magnetic flux generated by the first conductor 301 and the second conductor 302 wound around the noise canceling core is formed in the same direction in the noise canceling core, common mode noise is is removed

Also, referring to FIG. 3 , the power conversion device according to the present invention may include a first reactor 1700a and a second reactor 1700b. The first reactor 1700a and the second reactor 1700b may be connected to each other in parallel.

When the two reactors 1700a and 1700b are provided as described above, there are four conductors that can be wound. That is, the first conductive wire 301 and the second conductive wire 302 connected to both ends of the first reactor and the third conductive wire 303 and the fourth conductive wire 304 connected to both ends of the second reactor are to be wound around the noise removing core. can

Hereinafter, for convenience of explanation, the conductors 301 and 303 connected to the power source among both ends of each of the reactors 1700a and 1700b are defined as the input end conductors, and the conductors connected to the converter among both ends of each of the reactors 1700a and 1700b. (302, 304) is defined as the output conductor.

In order to implement the common mode noise removal method shown in FIG. 2 , with reference to FIGS. 3 and 4 , a method of winding a conducting wire around the noise removing core C1 in a conventional power conversion device will be described.

Referring to FIG. 3 , in the case of a conventional power conversion device, all the conductors 301 , 302 , 303 , and 304 connected to the first and second reactors are wound around one noise removal core C1 in the same direction.

In order to wind all the conducting wires in this way, the noise removing core C1 must be formed to have a sufficient size, and there is a problem in that a relatively expensive core is used to manufacture the power conversion device.

Hereinafter, referring to FIGS. 5 and 6 , in order to solve the above-described problem, a first noise removing core C2 that winds some of the plurality of conductive wires connected to both ends of the reactor unit, and a second noise removing core C2 that winds the rest A power conversion device including a core C3 is proposed.

5 and 6 , the first noise removing core C2 may wind the output end-side conducting wire of the first reactor 1700a and the input end-side conducting wire of the second reactor 1700b.

That is, the first noise removing core C2 may wind the second conductive wire 302 and the third conductive wire 303 in the same direction.

In addition, according to the embodiment shown in FIGS. 5 and 6 , the second noise removing core C3 may wind the input end-side conducting wire of the first reactor 1700a and the output end-side conducting wire of the second reactor 1700b. have.

That is, the second noise removing core C3 may wind the first conductive wire 301 and the fourth conductive wire 304 in the same direction.

5 and 6 , when the first noise canceling core C2 and the second noise canceling core C3 are used, the number of cores increases, but the size of each core decreases .

Since the unit price of the two cores having the size reduced in this way is cheaper than the unit price of the core having a larger size, according to the embodiments shown in FIGS. 5 and 6 , it is possible to reduce the manufacturing cost of the power conversion device.

Another embodiment of the present invention is described in FIGS. 7 and 8 .

Referring to FIGS. 7 and 8 , the power conversion device according to another embodiment of the present invention may include a noise removal core C4 that winds a conductive wire on the output end side of the reactor unit.

Specifically, the noise removal core C4 may wind the output terminal-side conductive wire 302 of the first reactor 1700a and the output terminal-side conductive wire 304 of the second reactor 1700b.

That is, the noise removing core C4 may wind the second conductive wire 302 and the fourth conductive wire 304 .

In particular, the output terminal-side conductive wire 302 of the first reactor 1700a and the output terminal-side conductive wire 304 of the second reactor 1700b may be wound around the noise removing core C4 in opposite directions.

In other words, the first reactor 1700a and the second reactor 1700b are disposed between an external power source and the converter, and the noise canceling core C4 includes a converter-side conductor 302 of the first reactor 1700a, and The converter-side conductive wire 304 of the second reactor 1700b may be wound in opposite directions.

On the other hand, the first magnetic flux (not shown) generated by the converter-side conductor 302 of the first reactor 1700a wound around the core C4 and the converter-side conductor of the second reactor 1700b wound around the core ( The second magnetic flux (not shown) generated by the 304 may be formed in the same direction in the noise canceling core C4 formed as a ring.

In another embodiment, the noise removal core C4 according to the present invention may wind any one of the conductive wires connected to both ends of the first reactor 1700a and the conductive wire connected to both ends of the second reactor 1700b. have. At this time, the currents flowing through the two conductors wound around the noise removing core C4 are in the same direction with respect to the reactor unit.

Features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

Claims (8)

delete delete delete delete delete a reactor unit connected to the power supplied to the power conversion device;
a converter to which the output voltage of the reactor unit is applied; and
It is connected to both ends of the reactor and includes a first noise removing core and a second noise removing core for removing common mode noise,
The reactor unit includes a first reactor and a second reactor,
The first reactor and the second reactor are connected in parallel,
The first noise removal core winds the output end-side conducting wire of the first reactor and the input end-side conducting line of the second reactor,
The second noise removal core is a power conversion device, characterized in that for winding the input end-side conducting wire of the first reactor and the output end-side conducting line of the second reactor. 7. The method of claim 6,
The power conversion device, characterized in that the output end-side conducting wire of the first reactor and the input end-side conducting line of the second reactor are wound around the first noise removing core in the same direction. 7. The method of claim 6,
The power conversion device, characterized in that the output end-side conducting wire of the second reactor and the input end-side conducting line of the first reactor are wound around the second noise removing core in the same direction.

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