KR20180101857A - Power transforming apparatus and air conditioner including the same - Google Patents

Abstract

The present invention relates to a power conversion apparatus, and more particularly, to a power conversion apparatus with an overvoltage protection function and an air conditioner including the same. The power conversion apparatus of the present invention comprises: a rectifying unit rectifying an alternative current (AC) voltage input from an AC power source; a power factor control unit including a switching device to perform a power factor improving operation on the voltage rectified by the rectifying unit; a direct current (DC)-link capacitor storing an output voltage of the power factor control unit; an inverter module generating an AC signal for driving a motor by using the voltage stored in the DC-link capacitor; a driving unit driving the power factor control unit; a control unit transmitting a driving signal to the driving unit and the inverter module; and an overvoltage protection unit sensing a charge voltage stored in the DC-link capacitor, and transmitting a drive cutoff signal to at least one of the driving unit and the control unit according to a charge voltage value.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion apparatus and an air conditioner including the same,

The present invention relates to a power conversion apparatus, and more particularly, to a power conversion apparatus including an overvoltage protection function and an air conditioner including the same.

Generally, a compressor of an air conditioner uses a motor as a driving source. These motors are supplied with AC power from a power conversion device.

Such a power conversion apparatus is generally known to include a rectifying section, a power factor control section, and an inverter.

First, the commercial voltage of the AC output from the commercial power source is rectified by the rectifying part. The rectified voltage at this rectifying part is supplied to the inverter. At this time, the inverter generates AC power for driving the motor by using the voltage outputted from the rectifying section.

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

Further, a DC-link capacitor in which a DC voltage is charged may be placed between the inverter and the converter.

When the voltage of the DC-link capacitor gradually rises to reach the overvoltage for various reasons during the operation of the power conversion apparatus, it is possible to stop driving of the inverter and the converter by sensing it in a micom constituting the control unit.

However, as described above, the microcomputer senses the overvoltage and takes a long time to operate. Thus, the voltage of the DC-link capacitor can be continuously increased until the command for shutting off the drive is transmitted. Therefore, there is a risk that the parts may be burned out.

Therefore, there is a need for a method for effectively preventing such a phenomenon.

SUMMARY OF THE INVENTION An aspect of the present invention is to provide a power conversion apparatus and an air conditioner including the same that can effectively protect at least one of a converter and an inverter module from an overvoltage.

According to a first aspect of the present invention, there is provided a rectifying device comprising: a rectifying part for rectifying an AC voltage input from an AC power source; A power factor control unit including a switching device for performing a power factor improving operation on a voltage rectified by the rectifying unit; A DC-link capacitor for storing an output voltage of the power factor control unit; An inverter module for generating an AC signal for driving the motor using the voltage stored in the DC-link capacitor; A driving unit for driving the power factor control unit; A controller for transmitting driving signals to the driving unit and the inverter module; And an overvoltage protection unit for sensing a charging voltage stored in the DC-link capacitor and transmitting a driving cutoff signal to at least one of the driving unit and the control unit according to the charging voltage value.

Here, the overvoltage protection unit may include: a sensing unit that senses a charging voltage stored in the DC-link capacitor; And a comparator for outputting a driving cutoff signal to at least one of the driving unit and the control unit according to an output of the sensing unit.

At this time, the sensing unit may include a distribution resistor connected in parallel to the DC-link capacitor.

The output of the comparator may be transmitted to a blocking signal input terminal of the power factor control unit and a blocking signal input terminal of the inverter module configured in the control unit.

At this time, the output of the comparator may be bypassed to the control unit before reaching the driving unit and the inverter module.

Here, the overvoltage protection unit may include: a sensing unit that senses a charging voltage stored in the DC-link capacitor; A comparator for outputting a high or a low signal according to an output of the sensing unit; And a drive switching unit for applying a low signal to an output terminal of the driving signal of the control unit according to the output of the comparator.

The driving switching unit may include a transistor having a base connected to the comparator and an emitter connected to an output terminal of the driving signal of the control unit.

Here, the DC-link capacitors may be connected in parallel at two places, and the power factor control unit may include two switching devices to drive the two DC-link capacitors.

Here, the inverter module may include a plurality of switching devices directly driven by the control unit.

According to a second aspect of the present invention, there is provided an air conditioner including the power conversion device.

The present invention has the following effects.

First, it can be quickly judged by the hardware configuration such as the distribution resistance and the comparator when determining the overvoltage.

In addition, when the overvoltage is applied, the operation of the converter and the inverter module is stopped to prevent the burnout of the converter and the inverter module.

1 is a circuit diagram showing a power conversion apparatus according to a first embodiment of the present invention.
2 is a circuit diagram showing a power conversion apparatus according to a second embodiment of the present invention.

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

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

1 is a circuit diagram showing a power conversion apparatus according to a first embodiment of the present invention.

1, the power conversion apparatus 100 includes a rectifier 110 for rectifying an AC power source 10, a converter 120 for controlling the power factor of the DC voltage rectified by the rectifier 110, An inverter module 140 for outputting a three-phase alternating current for driving the inverter 200 and a DC-link capacitor C1 disposed between the converter 120 and the inverter module 140 have.

The AC power source 10 may be connected to the rectifying unit 110 through a noise filter (N / Filter) 20.

The inverter module 140 outputs a three-phase alternating current, and the output current is supplied to the motor 200. Here, the motor 200 may be a compressor motor for driving the air conditioner. Hereinafter, the motor 200 is a compressor motor that drives the air conditioner, and the power inverter 100 is a motor driving device that drives such a compressor motor.

However, the motor 200 is not limited to a compressor motor and can be used in various applications using frequency-varying alternating voltages, for example, AC motors such as refrigerators, washing machines, electric trains, automobiles, and vacuum cleaners.

The motor drive apparatus 100 receives the AC power from the system, converts the power, and supplies the converted power to the motor 200.

The converter 120 converts the input AC power supply 10 into a DC power supply. The converter 120 may use a DC-DC converter operating as a power factor control (PFC) unit. In addition, such a DC-DC converter can use a boost converter. Optionally, the converter 120 may be a concept that includes the rectifier 110. Hereinafter, the converter 120 will be described by way of example using a step-up converter.

The rectifying unit 110 receives and rectifies the single-phase AC power supply 10 and outputs the rectified power to the converter 120 side. For this purpose, the rectifying part 110 can use a full-wave rectifying circuit using a bridge diode.

In this way, the converter 120 can perform the power factor improving operation in the process of stepping up and smoothing the voltage rectified by the rectifier 110.

The converter 120 includes an inductor L1 connected to the rectifying section 110, a switching element Q1 connected to the inductor L1, and a switching element Q1 connected between the switching element Q1 and the DC-link capacitor C1. And a diode D1.

The boost converter 120 is a converter that can obtain an output voltage higher than the input voltage. When the switching device Q1 is turned on, energy is stored in the inductor L1 while the diode D1 is shut off, and the DC- ) Discharges and generates an output voltage at the output terminal.

Further, when the switching element Q1 is interrupted, the energy stored in the inductor L1 at the time of the switching element Q1 is added and is transferred to the output terminal.

On the other hand, a plurality of DC-link capacitors may be connected to each other in parallel. For example, as shown in FIG. 1, two DC-link capacitors C1 and C2 may be provided.

The converter 120 capable of performing the power factor improving operation while charging the two DC-link capacitors C1 and C2 is composed of two inductors L1 and L2, a pair of inductors L1 and L2, Two diodes D1 and D2 connected to the inductors L1 and L2 and two switching elements Q1 and Q2 connected to the inductors L1 and L2.

This configuration may represent two converters 120 capable of performing a power factor improving operation while charging two DC-link capacitors C1 and C2. These two converters 120 can operate independently by driving the two switching elements Q1 and Q2. Therefore, hereinafter, one switching element Q1 and related operation will be mainly described. In addition, the remaining switching elements Q1 and associated operations may be the same as these switching elements Q1 and related operations.

Here, the switching device Q1 may perform a switching operation by a separate pulse width modulation (PWM) signal. That is, the PWM signal PWM1_conv transferred from the driving unit 151 for driving the converter 120 is connected to the gate (or base) terminal of the switching element Q1, so that the switching element Q1 outputs the PWM signal PWM1_conv The switching operation can be performed. Similarly, the switching element Q2 can perform the switching operation by the PWM signal PWM2_conv.

The driving unit 151 receives the converter driving signals PWM1 and PWM2 from the controller 150 and outputs the PWM signals PWM1_conv and PWM2_conv to the switching elements Q1 and Q2.

On the other hand, 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 metal oxide semi-conductor field effect transistor (MOSFET) and a bipolar transistor. The IGBT has a small driving power and is capable of high-speed switching, high-voltage conversion, and high current density.

In this way, the driving unit 151 can control the turn-on timing of the switching element Q1 in the converter 120 under the control of the controller 150. [ Thus, the converter driving signal for the turn-on timing of the switching element Q1 can be outputted.

Optionally, such a converter 120 may be omitted. That is, the output voltage through the rectifying unit 110 can be charged to the DC-link capacitor C1 without passing through the converter 120, or the inverter 140 can be driven.

On the other hand, the inverter module 140 includes a plurality of inverter switching elements Qa, Qb, Qc, Qa ', Qb', and Qc ', and controls the on / off operation of the switching element Q1 of the converter 120 Phase AC power supply of a predetermined frequency, and output the converted three-phase AC power to the three-phase motor 200.

More specifically, the inverter module 140 includes a pair of upper switching elements Qa, Qb, and Qc and lower switching elements Qa ', Qb', and Qc 'that are connected in series with each other, The switching elements can be connected to each other in parallel.

The switching elements Qa, Qb, Qc, Qa ', Qb', and Qc 'of the inverter module 140 may use power transistors and may be formed of insulated gate bipolar transistors gate bipolar mode transistor (IGBT).

The controller 150 may output the inverter driving signals PWM_u, PWM_v, PWM_w, PWM_x, PWM_y and PWM_z to the inverter module 140 in order to control the switching operation of the inverter module 140. [ The drive signals PWM_u, PWM_v, PWM_w, PWM_x, PWM_y and PWM_z of the inverter module 140 are used as switching control signals for the pulse width modulation method PWM to control the output current flowing through the motor 200 and the DC- C1) and can be generated and output based on the DC-link voltage.

That is, the inverter module 140 may include a gate driver (not shown) for driving the switching elements Qa, Qb, Qc, Qa ', Qb', and Qc '. For example, the inverter module 140 can be directly driven by the inverter driving signals PWM_u, PWM_v, PWM_w, PWM_x, PWM_y, and PWM_z output from the controller 150.

On the other hand, the charging voltage stored in the DC-link capacitor C1 is detected in the DC-link capacitors C1 and / or C2 (hereinafter referred to as C1) and the driving unit 151 and the control unit 150 and the overvoltage protection unit 160 for transferring the drive cut-off signal Fo_conv, Fo_inv to at least one of the plurality of switches.

The overvoltage protection unit 160 includes a sensing unit 162 for sensing the charging voltage stored in the DC-link capacitor C1 and at least one of the driving unit 151 and the control unit 150 according to the output of the sensing unit 162. [ And a comparator 163 for outputting a drive cut-off signal to any one of them.

At this time, the sensing unit 162 may include distribution resistors R1, R2, and R3 connected in parallel to the DC-link capacitor C1. That is, the voltage charged in the DC-link capacitor C1 can be input to the comparator 163 at an appropriate level by using the distribution resistors R1, R2, and R3.

The voltage distributed through the distribution resistors R1, R2 and R3 constituting the sensing part 162 is inputted to the negative terminal of the comparator 163 and the reference voltage is inputted to the positive terminal of the comparator 163, (+) Terminal.

The output of the comparator 163 may be transmitted to the input terminal of the shutoff signal Fo_conv of the power factor control unit (converter) 120 and the shutoff signal (Fo_inv) of the inverter module 140 configured in the controller 150.

The comparator 163 includes an operational amplifier 163a and setting resistors R4 and R5 and outputs a high signal or a low signal according to the magnitude of the voltage input from the sensing unit 162 .

At this time, the output of the comparator 163 may be bypassed to the controller 150 before reaching the driving unit 151 and the inverter module 140.

1, the output of the comparator 163 is supplied to the control unit 150 through a part connected to the input terminal of the shutoff signal Fo_conv of the controller 150 positioned immediately before the driving unit 151 Fo_conv) input stage. The output of the comparator 163 is connected to the cutoff signal Fo_inv of the controller 150 through a connection part 164 connected to an input terminal of the cutoff signal Fo_inv of the controller 150 positioned immediately before the inverter module 140, Lt; / RTI >

2 is a circuit diagram showing a power conversion apparatus according to a second embodiment of the present invention.

2, the power conversion apparatus 100 includes a rectifier 110 for rectifying an AC power source 10, a converter 120 for controlling the power factor of the DC voltage rectified by the rectifier 110, An inverter module 140 for outputting a three-phase alternating current for driving the inverter 200 and a DC-link capacitor C1 disposed between the converter 120 and the inverter module 140 have.

The driving unit 151 receives the converter driving signals PWM1 and PWM2 from the controller 150 and outputs the PWM signals PWM1_conv and PWM2_conv to the switching elements Q1 and Q2.

The controller 150 may output the inverter driving signals PWM_u, PWM_v, PWM_w, PWM_x, PWM_y and PWM_z to the inverter module 140 in order to control the switching operation of the inverter module 140. [ The drive signals PWM_u, PWM_v, PWM_w, PWM_x, PWM_y and PWM_z of the inverter module 140 are used as switching control signals for the pulse width modulation method PWM to control the output current flowing through the motor 200 and the DC- C1) and can be generated and output based on the DC-link voltage.

The rectifier 110, the converter 120, the inverter module 140, the DC-link capacitor C1, the driving unit 151, the control unit 150, and the like, which constitute the power conversion apparatus 100, The above description can be applied as described above. Therefore, redundant description is omitted.

Here, the overvoltage protection unit 160 may have a configuration different from that of the embodiment shown in FIG. 1. Hereinafter, the overvoltage protection unit 161 according to this other embodiment will be mainly described.

The overvoltage protection unit 161 according to the present embodiment includes a sensing unit 162 for sensing a charging voltage stored in the DC-link capacitor C1, a high- and a drive switching unit 165 for applying a low signal to the output terminal PWM_stop of the driving signal of the control unit 150 according to the output of the comparator 163 can do.

At this time, the sensing unit 162 may include distribution resistors R1, R2, and R3 connected in parallel to the DC-link capacitor C1. That is, the voltage charged in the DC-link capacitor C1 can be input to the comparator 163 at an appropriate level by using the distribution resistors R1, R2, and R3.

The voltage distributed through the distribution resistors R1, R2 and R3 constituting the sensing unit 162 is input to the positive (+) terminal of the comparator 163, and the reference voltage is input to the cathode of the comparator 163 (-) terminal.

The drive switching unit 165 includes a transistor Q3 whose base end is connected to the comparator 163 and whose emitter end is connected to the output terminal PWM_stop of the driving signal of the controller 150 through the blocking connection unit 166, . ≪ / RTI >

That is, the output signal of the transistor Q3 may be connected to the output terminal PWM_stop of the driving signal of the controller 150 through the blocking connection portion 166. [

Here, the DC-link capacitor C1 is connected in two places in parallel, as described above, and the power factor control unit (converter) 120 is connected to two switching elements C1, C2 to drive these two DC- And may include elements Q1 and Q2. A duplicate description thereof will be omitted.

Hereinafter, the operation of the first embodiment and the second embodiment of the present invention will be described with reference to Figs. 1 and 2, respectively.

First, the operation of the first embodiment will be described with reference to FIG.

The voltage applied to the comparator 163 through the sensing unit 162 is less than 3.88 V when the voltage of the DC-link capacitor C1 is a constant voltage that is determined to be an overvoltage, for example, less than 450 V.

At this time, the output of the comparator 163 becomes a high signal, and this high signal is inputted to the input terminal of the cutoff signal (Fo_conv) of the power factor control unit (converter) 120 and the cutoff signal Fo_inv of the inverter module 140, Lt; / RTI >

Accordingly, the converter 120 and the inverter module 140 perform normal operation. That is, when a high signal is applied to the input terminal of the shutoff signal (Fo_conv) of the power factor control unit (converter) 120 of the controller 150 and the input terminal of the shutoff signal (Fo_inv) of the inverter module 140, .

On the other hand, when the voltage of the DC-link capacitor C1 is equal to or higher than a predetermined voltage, for example, 450 V, which is determined to be an overvoltage, the voltage applied to the comparator 163 through the sensing unit 162 becomes 3.88 V or more .

At this time, the output of the comparator 163 becomes a low signal, and this low signal is inputted to the input terminal of the shutoff signal Fo_conv of the power factor control unit (converter) 120 and the shutoff signal Fo_inv of the inverter module 140, Lt; / RTI >

In this way, a low signal is applied to the input terminal of the cut-off signal (Fo_conv) of the power factor control unit (converter) 120 of the control unit 150 and the input terminal of the cutoff signal (Fo_inv) of the inverter module 140, It stops.

Accordingly, when the overvoltage is applied, the operation of the converter 120 and the inverter module 140 is stopped to prevent the converter 120 and the inverter module 140 from being burned.

Next, operation of the second embodiment will be described with reference to Fig.

The voltage applied to the comparator 163 through the sensing unit 162 is less than 3.88 V when the voltage of the DC-link capacitor C1 is a constant voltage that is determined to be an overvoltage, for example, less than 450 V.

At this time, a low signal is outputted from the comparator 163 and applied to the base end of the transistor Q3 constituting the drive switching unit 165. [

Therefore, the transistor Q3 does not operate, and the controller 150 performs a normal driving process.

On the other hand, when the voltage of the DC-link capacitor C1 is equal to or higher than a predetermined voltage, for example, 450 V, which is determined to be an overvoltage, the voltage applied to the comparator 163 through the sensing unit 162 becomes 3.88 V or more .

Then, a high signal is outputted from the comparator 163 and is applied to the base end of the transistor Q3 constituting the drive switching unit 165. [

At this time, the output signal of the transistor Q3 is applied to the output terminal PWM_stop of the driving signal of the control unit 150 through the blocking connection unit 166. [

Then, a low signal is applied to the output terminal (PWM_stop) of the driving signal of the controller 150 through the blocking connection unit 166, and the controller 150 stops the driving operation.

Accordingly, when the overvoltage is applied, the operation of the converter 120 and the inverter module 140 is stopped to prevent the converter 120 and the inverter module 140 from being burned.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100: power converter 110: rectifying part
120: Converter 140: Inverter module
150: control unit 151:
160, 161: Overvoltage prevention unit 162:
163: comparator 164: connection
165: drive switching unit 166:
200: motor

Claims (10)

A rectifying unit for rectifying an AC voltage input from an AC power source;
A power factor control unit including a switching device for performing a power factor improving operation on a voltage rectified by the rectifying unit;
A DC-link capacitor for storing an output voltage of the power factor control unit;
An inverter module for generating an AC signal for driving the motor using the voltage stored in the DC-link capacitor;
A driving unit for driving the power factor control unit;
A controller for transmitting driving signals to the driving unit and the inverter module; And
And an overvoltage protection unit for sensing a charging voltage stored in the DC-link capacitor and transmitting a driving cutoff signal to at least one of the driving unit and the control unit according to the charging voltage value. 2. The overvoltage protection circuit according to claim 1,
A sensing unit sensing a charging voltage stored in the DC-link capacitor; And
And a comparator for outputting a drive cutoff signal to at least one of the driving unit and the control unit according to the output of the sensing unit. 3. The apparatus of claim 2, wherein the sensing unit comprises a distribution resistor connected in parallel to the DC-link capacitor. 3. The method of claim 2, wherein the output of the comparator
The blocking signal input terminal of the power factor control unit and the blocking signal input terminal of the inverter module configured in the control unit. 5. The power conversion apparatus of claim 4, wherein the output of the comparator is bypassed to the control unit before reaching the driving unit and the inverter module. 2. The overvoltage protection circuit according to claim 1,
A sensing unit sensing a charging voltage stored in the DC-link capacitor;
A comparator for outputting a high or a low signal according to an output of the sensing unit; And
And a drive switching unit for applying a low signal to an output terminal of the driving signal of the control unit according to the output of the comparator. The power conversion device of claim 6, wherein the drive switching unit includes a transistor having a base end connected to the comparator and an emitter end connected to an output terminal of the driving signal of the control unit. The power conversion apparatus of claim 1, wherein the DC-link capacitors are connected in parallel at two points, and the power factor control unit includes two switching elements to drive the two DC-link capacitors. The power conversion apparatus according to claim 1, wherein the inverter module includes a plurality of switching elements directly driven by the control unit. An air conditioner comprising the power conversion device according to any one of claims 1 to 9.

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