KR20180092696A - Power transforming apparatus and air conditioner including the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion apparatus, and more particularly, to a power conversion apparatus having an arm-short prevention function of an inverter and an air conditioner including the power conversion apparatus. The present invention provides a power conversion apparatus comprising: an inverter including a plurality of switching elements corresponding to three phases; A gate driver for driving a switching element of the inverter; And a short prevention unit connected between an upper arm and a lower arm side of at least one phase of an input end side of the gate driving unit and blocking the driving of the gate driving unit when a high signal is simultaneously inputted to the upper arm side and the lower arm side .

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,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion apparatus, and more particularly, to a power conversion apparatus having an arm-short prevention function of an inverter and an air conditioner including the power conversion apparatus.

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.

On the other hand, the inverter may generate an arm-short due to foreign substances such as insects, moisture, or other abnormal conditions. If an overcurrent occurs due to a short circuit, a drive signal cutoff signal may be output from a sense resistor such as a control unit or a shunt resistor to stop the drive of the inverter.

However, when a malfunction of a control unit implemented by a micom or the like occurs, the error signal may not be sensed, which may lead to burn-out of the inverter.

Also, due to a sense of a sense resistor such as a shunt resistor, an overcurrent can not be detected. In such a case, the inverter may be damaged.

Therefore, even if a malfunction of the control unit or an erroneous detection of the sense resistor occurs as described above, there is a need for a method capable of preventing burnout of the inverter from a short circuit.

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 prevent burnout of an inverter when a short circuit occurs in an inverter.

According to a first aspect of the present invention, there is provided a power conversion apparatus comprising: an inverter including a plurality of switching elements corresponding to three phases; A gate driver for driving a switching element of the inverter; And a short prevention unit connected between an upper arm and a lower arm side of at least one phase of an input end side of the gate driving unit and blocking the driving of the gate driving unit when a high signal is simultaneously inputted to the upper arm side and the lower arm side .

Here, the shot preventing portion may be an AND gate connected between the upper rock side and the lower rock side of the at least one phase.

At this time, the AND gate may input a high signal to the drive signal cutoff terminal of the gate driver when a high signal is simultaneously input to the upper and lower arms.

The AND gate includes: a first AND gate connected between the upper arm side and the lower arm side of the U phase in the three phases; A second AND gate connected between the upper arm side and the lower arm side of the V phase of the three phases; And a third AND gate connected between the upper arm side and the lower arm side of the W phase of the three phases.

In this case, the first AND gate, the second AND gate and the third AND gate are connected in parallel to each other, and the output ends of the first AND gate, the second AND gate, and the third AND gate are connected to the lower- And may be connected to a gate driving unit for driving.

Here, it may further include an RC circuit located at the front end of the gate driving unit to remove noise.

At this time, the shot preventing portion may be connected between the RC circuit and the gate driving portion.

Here, the short-circuit prevention unit may be connected to a gate driver for driving the lower-arm-side switching element of the inverter.

According to a second aspect of the present invention, there is provided a power conversion apparatus comprising: an inverter including a plurality of switching elements corresponding to three phases; A gate driver for driving a switching element of the inverter; And a gate driving unit connected between an upper arm and a lower arm of each phase of the input side of the gate driving unit and driving a lower arm side switching element of the inverter when a high signal is input to the upper arm and the lower arm simultaneously And a short-circuit preventing part for cutting off the driving.

According to a third aspect of the present invention, there is provided an air conditioner including a power conversion device having the above-described configuration.

The present invention has the following effects.

According to the configuration of the shot preventing unit implemented by the AND gate of the present invention, when a short circuit occurs, even when no error due to congestion of the control unit is detected, the short prevention unit operates and a high signal is input to the drive signal cutoff terminal of the gate driving unit do.

Therefore, the drive signal is interrupted, and an error signal is output, thereby preventing the inverter (or the inverter module) from being damaged due to a short circuit.

The short-circuit prevention unit of such a hardware configuration can protect the inverter even if a fault is not detected due to congestion of the control unit or a false detection condition of the shunt resistor occurs.

1 is a block diagram showing a power conversion apparatus according to an embodiment of the present invention.
2 is a circuit diagram showing a power conversion apparatus according to an embodiment of the present invention.
3 is a circuit diagram showing a detailed configuration of a power conversion apparatus according to an embodiment of the present invention.
4 is a circuit diagram showing an example of an inverter and a gate driver.
5 is a signal diagram showing the operation of the lower gate driver.

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.

FIG. 1 is a block diagram showing a power conversion apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a power conversion apparatus according to an embodiment of the present invention.

1 and 2, the power inverter 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, A converter control unit 130 for controlling the converter 120, an inverter 140 for outputting a three-phase AC current, an inverter control unit 150 for controlling the inverter 140 and a converter 120 and an inverter 140, And a DC-link capacitor C between the DC-link capacitors.

This inverter 140 outputs a three-phase alternating current, and this 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 driving apparatus 100 may further include a DC voltage detection unit B, an input voltage detection unit A, an input current detection unit D, and an output current detection unit E.

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 device Q1 connected to the inductor L1, a capacitor C connected in parallel with the switching device Q1, And a diode D1 connected between the switching element Q1 and the DC-link capacitor C. [

The boost converter 120 can obtain an output voltage higher than the input voltage. When the switching device Q1 is turned on, the diode D1 is cut off and energy is stored in the inductor L1, and the DC-link capacitor C ) 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.

Here, the switching device Q1 may perform a switching operation by a separate pulse width modulation (PWM) signal. That is, the PWM signal transmitted from the converter control unit 130 is connected to the base (or gate) terminal of the switching element Q1, and the switching operation can be performed by the PWM signal.

The converter control unit 130 may include a gate driver for transmitting a PWM signal to a gate terminal of the switching element Q1 and a controller for transmitting a driving signal to the gate driver.

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 is a device capable of small driving power, high speed switching, high voltage conversion and high current density.

In this manner, the converter control unit 130 can control the turn-on timing of the switching element Q1 in the converter 120. [ Thus, the converter control signal Sc for the turn-on timing of the switching element Q1 can be output.

The converter controller 130 may receive the input voltage Vs and the input current Is from the input voltage detector A and the input current detector D, respectively.

Optionally, such converter 120 and converter control 130 may be omitted. That is, the output voltage through the rectifying unit 110 can be charged to the DC-link capacitor C without passing through the converter 120, or the inverter 140 can be driven.

The input voltage detecting section A can detect the input voltage Vs from the input AC power supply 10. [ For example, at the front end of the rectifying part 110. [

The input voltage detecting section A may include a resistance element, an OP AMP, or the like for voltage detection. The detected input voltage Vs can be applied to the converter control unit 130 to generate a converter control signal Sc as a discrete signal in the form of a pulse.

Next, the input current detection unit D can detect the input current Is from the input AC power supply 10. [ Specifically, it may be located at the front end of the rectifying section 110. [

The input current detection unit D may include a current sensor, a current transformer (CT), a shunt resistor, or the like, for current detection. The detected input voltage Is may be applied to the converter control unit 130 to generate the converter control signal Sc as a discrete signal in the form of a pulse.

The DC voltage detecting section B detects the pulsating voltage Vdc of the DC-link capacitor C. For such power detection, a resistance element, OP AMP, or the like can be used. The voltage Vdc of the detected DC-link capacitor C may be applied to the inverter control unit 150 as a discrete signal in the form of a pulse, and the DC voltage Vdc of the DC-link capacitor C The inverter control signal Si can be generated.

On the other hand, unlike the drawing, the detected DC voltage is applied to the converter control unit 130 and may be used for generating the converter control signal Sc.

The inverter 140 includes a plurality of inverter switching elements Qa, Qb, Qc, Qa ', Qb' and Qc ', and supplies the smoothed DC power source Vdc to a predetermined frequency Phase AC power supply of the three-phase motor 200, and outputs the three-phase AC power to the three-phase motor 200.

Specifically, the inverter 140 is a pair of the upper arc-side switching elements Qa, Qb, and Qc and the lower arm switching elements Qa ', Qb', and Qc 'that are connected in series to each other. And the lower arm side switching elements can be connected to each other in parallel.

As with the converter 120, the switching elements Qa, Qb, Qc, Qa ', Qb', Qc 'of the inverter can use power transistors, for example, an insulated gate bipolar mode transistor ; IGBT) can be used.

The inverter control unit 150 can output the inverter control signal Si to the inverter 140 in order to control the switching operation of the inverter 140. [ The inverter control signal Si is a switching control signal of the pulse width modulation method PWM and is based on the output current io flowing through the motor 200 and the DC- link voltage Vdc across the DC- Can be generated and output. The output current io at this time can be detected from the output current detecting portion E and the DC-link voltage Vdc can be detected from the DC-link voltage detecting portion B.

Between the inverter control unit 150 and the inverter 140 is provided a short prevention unit (AND gate) 160 for cutting off the output of the switching control signal when an arm-short occurs in the inverter 140 have. The short-circuit prevention unit 160 can prevent a malfunction due to a short circuit due to a short-circuit caused by a malfunction in the inverter control unit 150 or a sense resistor (shunt resistor) It can be prevented at the source. This will be described in detail later.

The output current detection section E can detect the output current io flowing between the inverter 140 and the motor 200. [ That is, the current flowing in the motor 200 is detected. The output current detection unit E can detect all of the output currents ia, ib, ic of each phase or can detect the output currents of two phases using the three-phase balance.

The output current detection unit E may be located between the inverter 140 and the motor 200. For current detection, a current transformer (CT), a shunt resistor, or the like may be used.

2, the inverter controller 150 includes a gate driver (not shown) for transmitting a PWM signal to the gate terminals of the switching elements Qa, Qb, Qc, Qa ', Qb' and Qc 'included in the inverter 140, a gate driver 155, and a control unit 156 for transmitting a driving signal to the gate driver 155.

At this time, the short-circuit prevention unit 160 is connected between the control unit 156 and the gate driver 155.

That is, the shot preventing portion 160 is connected between the upper arm side and the lower arm side of at least one phase of the input end side of the gate driving portion 155. The short prevention unit 160 transmits a signal for shutting off the driving of the gate driver 155 when a high signal is simultaneously input to the upper and lower arms.

3 is a circuit diagram showing a detailed configuration of a power conversion apparatus according to an embodiment of the present invention.

Referring to FIG. 3, the configuration between the DC-link capacitor C and the inverter 140 in the power inverter is mainly shown.

3 includes an inverter 140 including a plurality of switching elements Qa, Qb, Qc, Qa ', Qb', and Qc 'corresponding to three phases, A gate driver 155 for driving the switching elements Qa, Qb, Qc, Qa ', Qb', Qc ', and a gate connected between the upper arm and the lower arm on at least one of the input ends of the gate driver 155, (AND gate) 160. As shown in FIG.

The short-circuit prevention unit 160 may be configured to apply a high signal to the gate driver 155 to the gate driver 155 when the high- (CIN).

As described above, the short-prevention unit 160 may be implemented with an AND gate connected between the upper arm side and the lower arm side in at least one phase.

3, the AND gate includes a first AND gate 161 connected between the upper arm side IN_UH and the lower arm side IN_UL of the three phases, a first AND gate 161 connected to the upper arm phase IN_VH and the lower arm side And a third AND gate 163 connected between the upper arm side IN_WH and the lower arm side IN_WL of the W phase of the three phases.

At this time, the first AND gate 161, the second AND gate 162, and the third AND gate 163 are connected in parallel to each other. The first AND gate 161, the second AND gate 162, 3 The output terminal of the AND gate 163 may be connected to a gate driver (fourth driver) 154 for driving the lower arm side switching element of the inverter 140.

That is, the gate driving unit 155 includes a first driving unit 151 for driving the switching element Qa of the U-phase upper arm side IN_UH, a second driving unit 151 for driving the switching element Qb of the V-phase upper arm side IN_VH, A third driving unit 151 for driving the switching element Qc of the W phase upper arm side IN_WH and a lower driving unit 151 for switching the U phase, V phase and W phase lower arm IN_UL, IN_VL, IN_WL switching elements Qa ' , Qb ', and Qc').

With such a configuration, when a high signal is simultaneously input to the upper and lower arms of at least one of the U, V, and W phases, the AND gate 160 drives the fourth driver 154 The driving signal can be stopped by inputting a high signal to the signal blocking terminal CIN.

Here, the RC circuit 141 may be provided at the front end of the gate driver 155 to remove noise.

The RC circuit 141 connects the resistor and the capacitor to each end of the three phases to prevent the switching elements Qa, Qb, Qc, Qa ', Qb', and Qc 'from operating due to noise other than the PWM signal have.

At this time, the short-circuit prevention unit 160 may be connected between the RC circuit 141 and the gate driver 155. That is, the short-circuit prevention unit 160 implemented by the AND gate may be connected to the front end of the inverter 140.

Terminals IN_WH, IN_VH, IN_UH, IN_UL, IN_VL, and IN_WL, which receive signals from the control unit 156, may be positioned on the input side of the RC circuit 141. [ That is, the control signal input from the control unit 156 may be transmitted to the gate driver 155 after passing through the RC circuit 141. [

FIG. 4 is a circuit diagram showing an example of an inverter and a gate driving unit, and FIG. 5 is a signal diagram showing an operation of a lower gate driving unit. 5 shows the operation of the gate driving unit (fourth driving unit) 154 on the lower arm side.

A control signal (lower arms control input) on the lower arm side is input to the fourth driving unit 154 through the control unit 156. [

Usually, the inverter 140 may be subjected to a short circuit due to foreign matter such as insects, moisture, or other abnormal conditions. If an overcurrent occurs due to a short circuit, a high signal is input to the drive signal cutoff terminal CIN (CSC) of the gate driver 155 from the control unit 156 or a sense resistor such as a shunt resistor.

Then, the error signal (Fault Out Signal) changes from a high state to a low state to output an error state.

Then, the output current is cut off (c8), and the output (PWM output) of the gate driver 155 is cut off.

However, when the malfunction of the control unit 156 implemented by a micom or the like occurs, the error signal may not be sensed and the inverter 140 may be damaged.

Also, due to a sense of a sense resistor such as a shunt resistor, an overcurrent can not be detected. In such a case, the inverter 140 may be damaged.

However, according to the configuration of the short-circuit prevention unit 160 implemented by the AND gate of the present invention as described above, even when a short circuit occurs, even when an error is not detected due to congestion of the control unit 156, And the high signal is input to the drive signal cutoff terminal CIN (CSC) of the gate driver 155. [

Accordingly, the drive signal is interrupted, and an error signal is output, thereby preventing damage to the inverter 140 (or the inverter module) due to the arm short circuit.

The short-circuit prevention unit 160 having such a hardware configuration can protect the inverter 140 even when an error is detected due to congestion of the control unit 156 or a false sense of shunt resistance occurs.

Table 1 below shows the condition under which a cancer short occurs and its operation.

INPUT OUTPUT CIN Remarks IN_UH IN_UL IN_ VH IN_ VL IN_ WH IN_ WL AND GATE1 AND GATE2 AND GATE3 H H - - - - H H PWM interruption, Error occurrence, IPM  protect - - H H - - H H PWM interruption, Error occurrence, IPM  protect - - - - H H H H PWM interruption, Error occurrence, IPM  protect

Referring to Table 1, according to the present invention, when both the upper and lower arms of the respective phases are H signals, it is determined that a cancer short has occurred and an operation similar to the remarks can be performed.

That is, for example, when the high-side signal IN_UH and the low-side signal IN_UL of the U phase are both high on the input side INPUT, the first AND of the AND gate 160 on the output side OUTPUT The gate 161 is activated and a high signal H is input to the CIN terminal of the gate driver (fourth driver) 154.

Therefore, the PWM signal of the gate driving unit 154 is interrupted, and an error occurrence is noticed, whereby the inverter module IPM can be protected.

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 130: converter control unit
140: inverter 150: inverter controller
155: gate driver 156:
160: short-circuit prevention unit 161: first AND gate
162: second AND gate 163: third AND gate
200: motor

Claims (10)

An inverter including a plurality of switching elements corresponding to three phases;
A gate driver for driving a switching element of the inverter; And
And a short prevention unit connected between an upper arm and a lower arm side of at least one phase of an input end of the gate driving unit and interrupting the driving of the gate driving unit when a high signal is simultaneously input to the upper arm and the lower arm side And the power conversion device. The power conversion apparatus according to claim 1, wherein the short-circuit prevention unit is an AND gate connected between the upper arm side and the lower arm side of the at least one phase. 3. The apparatus of claim 2, wherein the AND gate inputs a high signal to the drive signal cutoff terminal of the gate driver when a high signal is simultaneously input to the upper and lower arms. Conversion device. 3. The semiconductor memory device according to claim 2,
A first AND gate connected between the upper arm side and the lower arm side of the U phase in the three phases;
A second AND gate connected between the upper arm side and the lower arm side of the V phase of the three phases; And
And a third AND gate connected between the upper arm side and the lower arm side of the W phase of the three phases. 5. The method of claim 4, wherein the first AND gate, the second AND gate and the third AND gate are connected in parallel with each other, and the output ends of the first AND gate, the second AND gate, Side switching element is connected to a gate driving part for driving the switching element. 2. The power conversion device of claim 1, further comprising an RC circuit located at a front end of the gate driver to remove noise. The power conversion apparatus according to claim 6, wherein the short-circuit prevention unit is connected between the RC circuit and the gate driver. The power conversion apparatus according to claim 1, wherein the short-circuit prevention unit is connected to a gate driver for driving a lower-arm-side switching element of the inverter. An inverter including a plurality of switching elements corresponding to three phases;
A gate driver for driving a switching element of the inverter; And
And a gate driver connected between the upper arm and the lower arm for inputting a high signal to the upper arm and the lower arm at the same time for driving the lower arm switching element of the inverter, And a short-circuit prevention unit for blocking the short-circuit current. An air conditioner comprising the power conversion device according to any one of claims 1 to 9.

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